Florida Institute of Technology Lunabotics

Systems Engineering Summary

Team: Florida Tech Lunabotics Team

Team Members: Rafiuddin Ahmed , Brittany Essink , Matthew Goldstein , Michelle Little, Allison Metzger, Jennifer Mori,

Advisors: Dr. Hector Gutierrez and Dr. Ronnal Reichard

Abstract   The Florida Institute of Technology Lunabotics team implemented a systems life cycle plan to design a robot for the 2012 NASA Lunabotics Competition. The robot was designed by analyzing the goals and constraints of the game, extensive research of previous competitors’ robots, and developing a list of system requirements to meet our team’s objectives. In addition to the design process, each team member underwent machine shop certification, allowing simultaneous construction and testing of the mechanical and electrical systems.

Table  of  Contents  Abstract ........................................................................................................................................... 1  

Section 1: Introduction .................................................................................................................... 1  

System Need ................................................................................................................................ 1  

Section 2: Literature Review .......................................................................................................... 2  

Section 3: Proposed Approach ........................................................................................................ 3  

Risk Mitigation Strategy ............................................................................................................. 3  

Conceptual Design ...................................................................................................................... 4  

Creation  of  a  Skilled  Team  ....................................................................................................................  5  

Trade  Study  ..........................................................................................................................................  5  

Concept  of  Operation  ...........................................................................................................................  6  

Capabilities  Development  Document  (CDD)  ........................................................................................  6  

Funding  and  Sponsorship  .....................................................................................................................  7  

Preliminary Design ...................................................................................................................... 7  

Systems  Requirements  Document  (SRD)  .............................................................................................  8  

Preliminary  Design  Review  ...................................................................................................................  8  

Machine  Shop  Training  and  Certification  .............................................................................................  9  

Safety  Plan  ..........................................................................................................................................  10  

Detailed Design and Development ............................................................................................ 10  

Parallel  Design  Process  .......................................................................................................................  11  

Bucket  .................................................................................................................................................  11  

Chassis  ................................................................................................................................................  14  

Arm  .....................................................................................................................................................  14  

Drive  Train  ..........................................................................................................................................  15  

Electronics  ..........................................................................................................................................  16  

User  Controls  ......................................................................................................................................  17  

Coding/Programming  .........................................................................................................................  17  

Production and Construction ..................................................................................................... 18  

Design  Margins  ...................................................................................................................................  18  

Testing  ................................................................................................................................................  18  

Operation Use and System Support .......................................................................................... 19  

Retirement ................................................................................................................................. 19  

Section 4: Objectives .................................................................................................................... 19  

Section 5: Methods/Tasks ............................................................................................................. 21  

Section 6: Results .......................................................................................................................... 24  

Requirements Flowdown Checklist .......................................................................................... 24  

Section 7: Conclusions/Recommendations ................................................................................... 25  

Future Design Improvements .................................................................................................... 25  

Section 8: References .................................................................................................................... 25  

Referenced Sources ................................................................................................................... 25  

Additional Sources .................................................................................................................... 25  

Appendix: Team Member Contributions ...................................................................................... 26  

Allison Metzger ......................................................................................................................... 26  

Matthew Goldstein .................................................................................................................... 27  

Michelle Little ........................................................................................................................... 27  

Brittany Essink .......................................................................................................................... 28  

Rafiuddin Arif Ahmed .............................................................................................................. 28  

Jennifer Mori ............................................................................................................................. 29  

   

Section  1:  Introduction   The Florida Institute of Technology Lunabotics team designed, fabricated and tested our lunabot, Pandia, using a life cycle plan to ensure that the final construction met design specifications. The systems engineering process followed the standard International Council on Systems Engineering (INCOSE) methodology that involved five stages: creation of a conceptual design, preliminary design, detailed design and development, production and construction, and operational systems use and support. In addition to these phases, the team has also created a retirement strategy for this year’s competition robot, allowing improvements for upcoming Florida Tech Lunabotics teams. The systems life span for the Florida Institute of Technology Lunabotics team was a year and a half, beginning in the 2011 spring semester in the Mechanical Engineering Design Methodologies class, commonly referred to as Junior Design. During this academic course, many project concepts were presented and teams were formed. In order for a project to be developed, three basic requirements needed to be fulfilled: a letter of intent of at least four team members, the identification of potential sources of funding, and the development of a conceptual design through the development of a Capabilities Development Document. After required system capabilities were identified, a Systems Requirement Document was created and a risk mitigation strategy was formulated and implemented, completing the first milestone. During the 2011 fall semester, the preliminary design and detailed design and development phases of the system were completed through the completion of a Preliminary Design Review and a Critical Design Review. In addition to resource allocation, physical design, and design analysis tasks, the team members underwent training and certification in the Florida Institute of Technology machine shop in preparation for the production/construction phases of the design process. One additional student completed OSHA respirator training for use during particular phases of construction. After the completion of the system specifications, construction of the robot occurred during the 2012 spring semester, followed by iterative system testing and performance improvement to maximize system performance. The final robot will begin the operational use and system support phases during the 2012 Lunabotics competition after which the Florida Institute of Technology 2012 Lunabotics team will be retired.

System  Need   Florida Institute of Technology’s College of Engineering graduates are often recruited into government and government contracting engineering positions. Maintaining connections to these agencies and businesses, as well as gaining additional publicity by demonstrating the quality of the student-engineered systems, ensures the success and growth of the university. Competitions like the NASA Lunabotics competition serve as an essential platform for demonstrating the quality of the Florida Institute of Technology programs. Participation of students in competitions is necessary in order grow the school’s funding, student population, and reputation.

Section  2:  Literature  Review  The Lunabotics mining competition is designed to help NASA Space Exploration in

discovering new ways to mine Tritium from the moon. Tritium can be used to implement cold fusion, which will act as an alternative energy source. Tritium is cleaner and more efficient than coal. If NASA is able to harvest tritium from the moon’s surface, it will make this clean energy cheaper in the future. (2)

The Lunabotics Mining Competition is a feasible project to do in the time span of one year for our senior design project can be built, tested and competition ready within a one-year time span. We will be able to build, test and be ready for the competition in May 2012 due to the fact that it has been done in previous competitions. In 2010, the first Lunabotics Mining Competition took place and teams were able to successfully complete the required tasks, which include building the lunabot and entering the Lunabotics Educational Outreach Program. Additionally the FIRST Robotics Competition teams have been able to design, build, and test robots within a six week time period. (3) In order to determine how to conceptually design the robot through the definition of capabilities, the team performed a trade study on the robot designs from the 2011 NASA Lunabotics competition. The top 10 teams scores and robot designs were analyzed to determine the best-performing mining method, while the top forty teams’ excavation rates were evaluated to determine the objective capability for the Florida Institute of Technology lunar simulant excavation goal.

Team Excavated Mass (kg)

Team Excavated Mass (kg)

Laurentian 237.4 Virginia Tech 79 North Dakota 172.2 Colorado School of Mines 72 West Virginia 106.4 Alabama 63.2 Embry Riddle– Prescott 85.4 John Brown 50 Auburn 80 Southern Indiana 37.6

Two of the top three scoring teams’ robot designs were found to use a bucket method for excavation, indicating that a bucket design had a high level of performance and should be utilized in robot design. The team set a goal of placing in the top forty teams after examination of the 2011 scores. It was determined that the objective for lunar simulant excavation should be 35 kg in 10 minutes. Throughout research, the method of maneuverability has been one of the major issues of the robot. Watching videos of other teams from the 2011 Lunabotics Competition, there were two main designs utilized which either utilized wheels or track. The two drive train options were investigated to determine which type of system should be implemented. Treads were found to provide a high level of traction, however research of previous lunar vehicles concluded that wheels offered better maneuverability and the capability of being able to completely seal the moving parts of the robot. For these reasons, we chose to use a wheel based drive train.

Section  3:  Proposed  Approach   The design approach to create a robot to compete in the NASA 2012 Lunabotics competition, utilized a linear systems life cycle to develop and construct a remotely operated excavation robot to compete.

Figure 1: Linear Systems Life Cycle Diagram

The systems life cycle starts with the identification of the system need, then proceeds to the generation of a conceptual design, a preliminary design, a detailed design, a construction/production period, a system operation period, and concludes with the systems retirement. In addition to following the system life cycle, a risk mitigation strategy was implemented to increase the system functionality, while minimizing time and schedule costs.

Risk  Mitigation  Strategy   Throughout the development process of the system, there were inherent risks associated with the robot design and construction, consisting of budget, technical, schedule, and labor risks. Budgetary risks consist of spending monetary resources beyond the allotted budget. Technical risks are the complexity of a component, subsystem, or program, which leads to the production of a component falling outside allotted tolerances and/or failing to function. Schedule risks relate to delays that occur in scheduled tasks that can prevent a product from being ready on time. Labor risks are a shortage of labor-hours due to unforeseen consequences, such as a worker’s personal commitments, health issues, or other excusable absences from working during a scheduled period.

In order to minimize these risks, certain processes were incorporated into the life cycle phases of the project as part of a comprehensive risk mitigation strategy. During the conceptual design phase, funding was pursued so as to establish a working budget for the system, minimizing budgetary risks. During the preliminary design phase, the team was machine shop trained and certified and produced a safety plan to reduce technical and scheduling risks. The team was also able to review inventory of potentially usable scrap materials, reducing budgetary risks. The team’s conceptual design review formally outlined estimated needs for materials and labor processes, allowing for the development of machine shop resource allocations through preemptive scheduling, reducing schedule risk. During the detailed design and development phase, a top-down design technique was implemented to distribute budgetary, weight, and dimensional allotments to ensure each system and subsequent components were designed within available resource limitations, reducing budgetary and technical risks. These designs were then tested and validated to ensure components would perform at the required levels, minimizing technical risk. This phase’s subsystem design process was governed by a work break down structure (WBS) to schedule the timeframe and responsibilities of each subsystem design, reducing schedule risk and labor risks. After the formal development of the system capabilities, the systems requirements (SPEC A) were formulated, allowing for the definition of the subsystem requirements (SPEC B), component requirements (SPEC C), and material requirements (SPEC D) to be defined. The SPEC C and SPEC D requirements led to the formulation of a bill of materials, formally outlining what materials and components were necessary for the construction of the lunabot. Any usable scrap materials from the on campus machine shop were claimed, while the rest of the components and materials were ordered before robot construction, reducing budgetary and schedule risk. The purchased and claimed materials were ordered and reserved to allow for at least ten percent of excess material to allow for the fabrication of at least two spare parts, to minimize schedule risk, while at least two spare components were ordered, where the budget allowed.

With completed construction of the mechanical system, the lunabot’s sub-systems underwent testing to ensure the system functioned within the designated parameters. Any errors that occurred during construction were corrected, minimizing potential failure risks. During the time before competition, maintenance procedures and spare parts were fabricated to ensure the lunabot would achieve the team’s objectives during competition. During competition, the lunabot will undergo regular maintenance procedures to ensure the system performs reliably.

Conceptual  Design   After the need to design a robot to compete in the 2012 NASA Lunabotics Competition was identified, the team for the Florida Institute of Technology was formed of mechanical and aerospace engineers, each with a specific and unique skill set that encompassed the areas of: CAD, systems engineering, optimization, ANSYS, drive train design, mechatronic design, and project management. The team analyzed the Lunabotics Competition manual and performed a trade study to formulate a capabilities development document. After completion of the conceptual design and required capabilities, the team procured funding for the system’s construction.

Creation  of  a  Skilled  Team  The core Lunabotics team was formed out of a diverse group of six students, each with

unique and valuable skillsets relative to the systems development and construction. The majority of the team had experience with the FIRST Robotics Competition (FRC), which greatly familiarized the team with the 6-week period allocated for design, construction, and testing of the robotic systems. The team members had unique skill sets which allowed them to specialize in the tasks of: project leader/project management, safety planning, CAD modeling and top down design, mechatronic and electronics design, systems engineering, linear programming, and ANSYS testing. The team was supervised by Dr. Gutierrez, a mechanical engineering professor and expert in mechatronic systems, who served as an additional knowledge and technical resource. Additional technical support and labor was provided through the Florida Tech Robotics Club and the current Junior Design class.

In addition to the team’s knowledge and experience base, the team had access to a variety of design software, as well as a fully equipped machine shop. Software packages available for the system’s life cycle included: MATLAB, Pro Engineer Wildfire 5.0, ANSYS Workbench, and the Microsoft Office Suite. The on-campus machine shop is well equipped with a 3-axis CNC milling machine, TIG and MIG welding capabilities, as well as a wide assortment of traditional milling machines, lathes, power tools, hand tools, presses, taps, dies, clamps, and a variety of other equipment. The machine shop is overseen by three full-time machinists who assist and provide advice for parts manufacture.

Trade  Study   In order to determine how to conceptually design the robot through the definition of capabilities, the team performed a trade study on the robot designs from the 2011 NASA Lunabotics competition. The top 10 teams scores and robot designs were analyzed to determine the best-performing mining method, while the top forty teams’ excavation rates were evaluated to determine the objective capability for the Florida Institute of Technology lunar simulant excavation goal.

Team Excavated Mass (kg)

Team Excavated Mass (kg)

Laurentian 237.4 Virginia Tech 79 North Dakota 172.2 Colorado School of Mines 72 West Virginia 106.4 Alabama 63.2 Embry Riddle– Prescott 85.4 John Brown 50 Auburn 80 Southern Indiana 37.6

Two of the top three scoring teams’ robot designs were found to use a bucket method for excavation, indicating that a bucket design had a high level of performance and should be utilized in robot design. The team set a goal of placing in the top forty teams after examination of the 2011 scores. It was determined that the objective for lunar simulant excavation should be 35 kg in 10 minutes.

The trade study also concluded two primary methods of drive train construction: treads and wheels. The two drive train options were investigated to determine which type of system should be implemented. Treads were found to provide a high level of traction, however research of previous lunar vehicles concluded that wheels offered better maneuverability and the capability of being able to completely seal the moving parts of the robot. For these reasons, we chose to use a wheel based drive train.

Concept  of  Operation   After analyzing previous competition robots and the 2012 competition’s rules and regulations, the team formulated a concept of operation to define how the system should function on a basic level. After positioning the lunabot at a specified position on the field, the robot would power up and a preinstalled sub-routine or the system user pilot the lunabot to the excavation area and engage in its excavation procedures. After the bucket was filled to an optimal capacity with lunar simulant, the lunabot would navigate back the collection bin to dump the excavated lunar simulant into the collection bin. Determining the use of manual control over a fully autonomous robot is dependent on time allowances during construction, as well as team ability. The human operator will control all robot functions with a goal to function autonomously in the future. If the team reaches autonomy, the operator will supervise the robot’s activities as a failsafe. The mining cycle would continue until time runs out, the battery is exhausted, or a failure requires mission abortion.

Figure 2: General Concept of Operations Diagram

Capabilities  Development  Document  (CDD)   After performing a trade study and analyzing the competition rules, a series of capabilities the system were identified. The identified capabilities have two levels of satisfaction associated with them. A threshold is the minimum acceptable level that must be met, and an objective is the desired goal level of performance. If specific threshold and objective levels for a capability are not directly stated, it is assumed that the listed capability threshold is equal to the objective. The identified capabilities served as a guideline when determining the system requirements. The use of the word “should” implies that the robot will need to meet the capability to properly function, however the capability listing is not binding, due to potential alterations when specific systems designs are proposed.

Table 1: Capabilities Development Document Summary Table

1.0 The robot should conform to the construction constraints listed in the in the 2012 NASA Lunabotics Competition Manual

1.0.1 The robot should conform to the physical dimensions and weight constraints listed in the 2012 NASA Lunabotics Competition Manual

1.0.2 The robot should have an electronics system that passes inspection and is equipped with a kill switch

1.1 Threshold: The robot should be able to complete the required outlined competition objectives Objective: The robot should compete and place within the top forty teams

1.1.1 The robot should have a battery life that lasts the length of competition at a minimum 1.1.2 Threshold: The robot should be able to consistently excavate at least 10 kg of regolith in 10

minutes Objective: The robot should be able to consistently excavate at least 35 kg of regolith in 10 minutes

1.1.3 The robot should be able to transport the excavated regolith to the designated collection bin 1.1.3.1 The robot should be able to move around the arena in a time-efficient and stable manner 1.1.3.2 The robot should have the capability to transport collected regolith without significant loss 1.1.3.3 The robot should be able to quickly and effectively transport collected regolith from the

regolith excavation mechanism to the designated collection bin 1.2 The robot should be safe to operate remotely by a user and/or autonomously 1.3 The robot should be designable for construction in a 1.5 semester timeframe and within a

budget of $10,000. 1.3.1 The robot construction should maximize the use of standardized components 1.3.2 The robot construction should maximize the percentage use of ordered raw materials 1.3.3 The robot should be made to maximize the use of a modular design to simplify construction 1.4 The robot design should minimize its mass 1.5 The robot should be designed for component re-use after retirement

Funding  and  Sponsorship  Upon completion and approval of design of our lunabot from the team and our academic

advisors, a budget was created and funding was pursued. The College of Engineering at Florida Institute of Technology was a major sponsor, contributing $6000 to the team budget. Additionally, and the team also won a scholarship from the Missile Range and Space Pioneers for an additional $4000.

Preliminary  Design   The team advanced the design to a preliminary level through the successful completion of a preliminary design review (PDR). During the formulation of the PDR, formal design requirements were outlined by means of a system requirements document. A rudimentary subsystem design schedule was formulated, and construction materials were investigated. During this phase, the team prepared for the detailed design and development phase and production phase through training and certification in the on-campus machine shop. The team was prepared to proceed to preliminary design through familiarization with the constraints, production capabilities, and manufacturing tolerances of the machine shop equipment: ±.001 in. Before working in the machine shop, the team was required to submit a live safety plan that reflected proper safety procedures and practices for manufacturing and included Material Safety Data

Sheets (MSDS) for any potential materials that would be used in the robot’s construction, and safety procedures and practices.

Systems  Requirements  Document  (SRD)   Upon completion of the capabilities development document, specific requirements were documented to meet the identified capabilities. The identified requirements have two levels of satisfaction associated with them as previously stated. The identified requirements served as a guideline when determining the system specifications in the detailed design and development phase. The use of the word “will” is binding, requiring the team to meet the specified requirements however no specific method is required at this stage. The definition of requirements begins at the system level (SPEC A) wherein requirements for system functionality are defined. To meet the system function requirements, the subsystems needed to meet the system functions identified with their requirements defined (SPEC B). Sub-systems are an assemblage of purchasable components and manufactured parts. The requirements for the sub-systems have been identified and the components and parts that are needed to construct them are identified (SPEC C). Any part that is not able to be purchased must be fabricated and the materials required for fabrication is then identified (SPEC D).

Preliminary  Design  Review   The preliminary design review was conducted during the 2011 fall semester and formally summarized the progress of the system’s development. In addition to presenting the literature review, trade study, and formal design capabilities, the document began the formulation of the WBS, SPEC C, SPEC D, and required tool list, SPEC E. The basic tasks of the WBS consisted of the following:

1.   Generate system and subsystem specifications through specific designs of the: chassis, drive train, bucket, arm, electronics/power system, program structure, user controls, and video feed back system

2.   Expand subsystem design options through use of optimization routines, to minimize weight and cost, while maximizing subsystem performance

3.   Construct major structural components and parts options in Pro Engineering Wildfire 5.0 and stress tests in ANSYS

4.   Expand SPEC C and SPEC D requirements to develop a formal bill of materials (BOM) 5.   Determine required fabrication processes for system construction 6.   Determine dependent and parallel fabrication processes 7.   Organize system construction process and assign tasks by expanding WBS 8.   Determine system testing procedures and assign by expanding WBS

A summary of the SPEC C and SPEC D requirements, as well as the tool needs in sub-system fabrication processes are identified below:

Table 2: SPEC C, SPEC D, and SPEC E Summary Table

Chassis Required Materials: Aluminum tubing (1x1 or 1x2 at 1/16th or 1/8th or 1/4th

thickness) Required Tools: Band saw, chop saw, TIG welder, grinder, power drill, safety glasses, welding mask

Drive Train Required Materials: 2 gear boxes, 4 wheels, 4 wheel hubs, 4 axils and mounting assemblies, 8 bearings, 4 drive gears, 2 chains, 2 tensioner systems, lubricant, wires, safety glasses Required Tools: Hand tools, power drill, milling machine, lathe, grinder, band saw

Bucket Required Materials: Aluminum sheet (1/32nd or 1/16th or 1/8th or 1/4th thickness), unidirectional carbon fiber fabric, muli-directional polyester mat, resin Required Tools: Metal sheet roller, grinder, jig saw, power drill, hand tools, safety glasses, vacuum pump, plastic tubing, peel ply, infusion media, vacuum bag

Arm Required Materials: Aluminum tubing (1x1 or 1x2 at 1/16th or 1/8th or 1/4th thickness), large linear actuator (for arm movement), small linear actuator (bucket movement), 2 axles, 4 bearings, lubrication, actuator mounts Required Tools: Band saw, chop saw, TIG welder, grinder, power drill, safety glasses, welding mask

Electronics Required Materials: 12 V battery, wiring, micro controller, motor controllers, wireless transmitter/receiver, acrylic sheeting(for component mounting), screws, wire wrap, miscellaneous components Required Tools: Soldering iron, USB microcontroller interface, wire strippers, wire cutters, pliers, band saw, hand tools, safety glasses

User Controls Required Materials: Joystick, buttons, transmitter, kill switch Required Tools: Soldering irons, hand tools, safety glasses

Video Feedback

Required Materials: Video streaming camera, video transmitter, video receiver, monitor, cables, mounting screws Required Tools: Soldering iron, power drill, hand tools, safety glasses

Machine  Shop  Training  and  Certification   After formulating the SPEC A, B, C, and D requirements and the tools needed for system fabrication, the team went to train in the on-campus machine shop for certification and familiarization with the tools required for the building process. The certification process was a 30 hour long course which instructed in the layout of the machine shop, the safety and operating procedures for milling machines, lathes, grinders, band saws, taps, dies, calipers, micrometers, as well as an assortment of hand tools. The team was also taught to identify machining tolerances and the commercially available materials and tooling sizes, allowing the team to begin the detailed design and development phase. The team was also able to communicate with the three full-time machinists working in the shop, creating an active dialog in which component designs were improved and manufacturing processes streamlined.

Safety  Plan   The team drafted a safety plan in order to obtain approval to manufacture their system in the on-campus machine shop. The safety plan was a living document that analyzed the risks associated with every process required to fabricate the robot. It provided risk mitigation techniques to prevent user injury and minimize manufacturing errors. MSDS were also required to for every material that the team used in the construction of the robot. The safety plan’s risk mitigation was implemented in three steps:

1.   Identify the risks 2.   Identify the impact and likelihood of the risk 3.   Identify methods to minimize risks

This process is exemplified in the following excerpt: Risk III.C: Dump bucket failures can result from overloading the bucket with more weight than it is designed to handle.

A material failure will occur if the pressure on the bucket exceeds the fracture strength of the material, which can cause the bucket to fracture and/or delaminate. The probability of this type of failure is dependent on the dimensions of the bucket and fracture strength of the material that comprises it. Prevention of failure due to fracture will be to design within the material’s limit by not exceeding the fracture strength.

In addition to a safety plan, safety margins were incorporated into selection of components and the design of parts to prevent failure from fracture and/or plastic deformation from unforeseen forces acting on the robot during use. During the design of each of these sub-systems, a safety factor of 5 was incorporated to prevent system damage, and ensure to the robot will always operate in a safe and reliable manner.

Detailed  Design  and  Development   The detailed design and development phase occurred after the approval of the PDR, and lasted for the second half of the 2011 fall semester. During this phase, the team designed the robot subsystems with manufacturing specifications through various forms of documentation, as well as finalized the BOM and WBS. Several iterative and linear programming optimization procedures were used to optimize the subsystem dimensions for weight and cost assuming certain physical dimension, monetary, labor-hour, and weight constraints for each of the subsystems. Once dimensions for a part or component were completed, a stress analysis was performed using ANSYS to determine the minimum thickness that could be used safely for a part of a given material type. Materials and components were then selected by through trade off analysis, by comparing the labor hours to make the part, weight, and cost for each material option. The lunabot was designed in British Imperial system, due to the availability of tools in the on-campus machine shop. Parts for the robot were manufactured within a tolerance of ±.005 inches. The finalized specifications system and subsystem are outlined in the combined CAD rendering of the robot and the electronics diagram, while the specifications for components and raw materials were specified in the BOM. The specifications were presented for evaluation in the form of a Critical Design Review (CDR) which, after approval, led to the construction/production phase.

Since the system has a requirement to be recycled for following years’ competitions and a requirement to be easily serviceable, the design of the robot is modular, allowing the robot to be disassembled into its sub-systems and then further disassembled into its parts and components. This modular design not only allows for a highly serviceable design, but also allows for entire subsystems, like the chassis, as well as individual components to be recycled for use in later years.

Parallel  Design  Process   Each of the team members was trained in a specific area during the preliminary design phases, allowing them to specialize in certain tasks during the detailed design phase. These specializations allowed the team members to complete several design processes in parallel, expediting the design time. A top-down approach was used to determine the cost, physical dimensions, mass of each subsystem, as well as the method by which the sub-systems interfaced. Knowing the constraints an individual subsystem as well as their interfaces, the team was able to implement a parallel design process. The independent design process allowed for the bucket, drive train, programming, and electronics to be designed in parallel. After the determination of the drive train and bucket dimensions, the frame and then arm were designed. Upon completion of the drive train and electronics, the human interface was designed.

Figure 3: Sub-System Interface Diagram

Bucket   The bucket was the first subsystem designed for the robot, as its dimensions govern the dimensions of the chassis and arm systems. From evaluation of the trade study and the system requirements, it was determined that a front loading bucket design would be implemented; however, the bucket shape, physical dimensions angle of attack needed to be determined with the

goal of maximizing the robot’s excavation performance. A sponsoring professor aided in the decision of material selection for the bucket, by donating the materials and allowing the use of tools required to fabricate the bucket out of carbon fiber. The decision of material choice determined the thickness (t) of the bucket, setting it at t= .11 in. Since the bucket would be comprised a compilation of carbon fiber, matting, and resin, the material density (pmat) was taken to be an unknown constant and set at pmat = 1. The bucket shape was the first obstacle to overcome in the bucket design as there were two considerations: should the bucket be rounded or rectangular, and should the bucket’s top face be open or should the bucket be of a closed design? A design tradeoff study was performed with the following findings:

Table 3: Bucket Design Trade Study Summary Table Advantages Disadvantages Rectangular Shape

-Easy to design with simple geometry -Straightforward construction method -Larger contained volume of regolith for size

-Heavy design with at least 4 distinct sides -4-5 pieces need to be cut instead of 3 -Regolith may stick to corners -Composites have higher risk of delamination with distinct corners

Rounded Shape

-Low weight to contained volume design -Made of only three components

-Center piece must be sent off to be rolled -Smaller regolith containment for physical volume

Open Design

-Lightweight -Less work to manufacture

-Structurally weaker than closed design -Possibility of regolith loss during robot transport

Closed Design

-Structurally strong -More effective at containing regolith

-Higher weight design -More labor-hours to manufacture

Based on the findings of the tradeoff study, a rounded shape bucket with an open top was

implemented. Given the bucket shape, the bucket angle of attack, the angle at which it contacts the flat plane that represents ideal ground was determined through a literature review. It was determined that an angle of attack of six degrees provided the greatest rate of granular flow [1]. The relations between granular flow, angle of attack, robot velocity, and bucket width were determined as in the following diagram, and gave an estimate for the volumetric collection rate of the bucket design.

Figure 4: Angle of Attack Calculation Diagram

Assumptions:

§   Bucket is initially level to the surface of the regolith §   Pivot point for angular displacement is measured from surface of the regolith §   Ground surface is level

§   No resistance to granular flow from inside bucket

Volumetric Flow Rate Cross Sectional Area of Flow Depth of Penetration ∀= 𝐴 ∗ 𝑣 𝐴 = 𝑦 ∗𝑊 𝑦 =  L ∗ sin 𝜃

Table 4: Bucket Angle of Attack Variable Definitions Variable Definition Variable Definition

∀ Volumetric Flow Rate W Width of bucket A Cross sectional area of flow L Bucket length v Velocity of Bucket Ѳ Bucket angle relative to field y Depth of bucket penetration

After determination of the regolith volumetric flow rate model, the bucket dimensions

were determined through the formulation of a non-linear optimization problem solved using MATLAB. The optimization problem was designed to determine what bucket dimensions would lead to the production of a bucket design that maximized granular flow and containable regolith while minimizing mass. However, the capacity of the bucket was set at a minimum of 40 kg of regolith to meet SRD 2.1.3.3.1. The density for the collected regolith was assumed to be 93.65 lbf/ft^3.

The optimization routine was formulated to determine the length (L), width (W-2t), radius (r), as well as the granular flow constant (G), volume of regolith (V), bucket mass (M) dimensions for the pieces comprising the bucket. The formulation of the optimization routine is seen below:

Figure 5: Bucket Optimization Diagram

Table 5: Bucket Optimization Formulation

Objective Function 𝑀𝑎𝑥𝑖𝑚𝑖𝑧𝑒:      2𝑉 + 𝐺 −𝑀  Volumetric Capacity   V = .5*3.14159*(r^2)*W + .5*2*r*L*(W-(2*t))  Granular Flow Coefficient   G = (W- 2t)*L*sind(6)  Bucket Mass   M = pmat*t*(A1 +2*A2)  Area of Piece 1   A1 = L*W + (3.14159*r*(W-2*t))  Area of Piece 2   A2 = .5*3.14159*(r^2) +.5*L*2*r  Area 2 = Area 3   A2 = A3  

Table 6: Bucket Decision Variable

 

 

 

Chassis  After the determination of the bucket dimensions, the chassis was designed. The chassis

design was modeled after successful and proven FIRST robotics robot frames, wherein the frame consists of a rectangular outer frame with inner crossbeams that serve as supports for mounting and increase the robot’s rigidity. A dimensional allotment was given to the chassis of 75% of the width and length constraint to allow for a preliminary design, with adjustment made after the bucket dimensions were determined.

The frame was designed to be made of 1x2 in thick Aluminum 6061 tubing. Many FIRST robotics frames are built using this type of tubing due to its weight-to-strength and cost-to-performance ratios. Little ANSYS testing was needed to confirm that the tubing would not fail under loading, as experiences from FIRST robotics have shown that frames made of this type of material endures 120-lb robots impacting them at 12 ft/s with minimal damage. Since the NASA Lunabotics mining competition does not allow robot-to-robot contact, the only impacts that can occur happen due to robots colliding with objects in the field or robot tipping. Both forms of impact are less forceful than what is experienced in FIRST competitions and therefore the tubing selection was deemed adequate.

The frame’s dimensions are designed to lower and center the robots center of mass as much as possible to minimize tipping moments. The space allotted for the drive train places the wheels as far apart from each other as possible, while utilizing the robot’s width to minimize weight imbalances. The robot arm was designed to be positioned at the back of the frame, to distribute its weight and the loads of collected regolith, and minimize tipping moments while the arm is in motion. To prevent regolith particle buildup in the electrical and mechanical components, the frame design uses of lightweight acrylic sheets to enclose all unsealed electrical and mechanical components. The enclosure of sensitive components prevents particle build-up, which can cause electrical components to short out or overheat, and mechanical component joints to cease functioning.

Arm   Upon determination of the bucket and chassis dimensions, enough data was available proceed with designing the arm. The function of the arm is to change the height of the bucket into the four required positions; the arm must be able to allow the bucket to intersect the plane of the playing field surface at the designated AOA, raise the front edge of the bucket 0.5 meters over the collection bin while it is at 90° incline to allow it to dump excavated materials, and travel with the bucket at a height that minimizes the tipping moment when traveling with a

Volumetric Capacity Constraint   V ≥ 315 in^3  

Variable   Range   Increment  Radius of Bucket   0.125 ≤ r ≤ 7.00 (in)   0.125 in  Width of Bucket   0.125 ≤ W ≤ 24.5 (in)   0.125 in  Length of Bucket   0.125 ≤ L ≤ 15.0 (in)   0.125 in  Material Thickness   t = 0.110 (in)   n/a  Material Density   pmat   n/a  

loaded bucket. The arm also needed to be rigid enough to maintain the forces and moment generated while the bucket was excavating and while transporting a load of regolith across the field.

To minimize the technical complexity of the arm, while maximizing its strength, a three link system was chosen as the general design for the arm, where welded supports rising up from both sided of the frame served as the grounded link, the arm served as a slider, and the liner actuator served as a liner crank. All three links were connected by revolute joints; as the linear actuator moves the angle of the arm relative to the frame increases, increasing the height of the bucket relative to the playing field surface. Since the containable volume of regolith was known, the maximum load of the bucket on the arm could be determined. By analyzing the load of the bucket, it was determined that two 12 inch stroke linear actuators, each generating a force of 100 lbf, would be utilized to create a double three bar linkage system.

The next design step was to determine the design of the arm linkage itself. Two designs were considered: a one piece thick walled tube arm and a parallel two main length tube arm with cross bracing, where two of tube ran the length of the arm, and three cross braces connected them to add rigidity. To ensure the arm would be stable, the parallel two main length tube arm with cross bracing was chosen as it provided a higher level of rigidity, as well as allowed for easier mounting of the bucket and actuators. Using the dimensions of the frame and arm, and range of motion required for both, an iterative graphical solving known as dimensional synthesis was utilized to determine the length of the arm, height of its mounting, and placements of the linear actuators to move the arm and bucket respectively. Multiple runs were conducted for each placement determination, and an optimal solution was found for the respective dimensions. Once the dimensions were determined, the tubing that comprised it needed to be selected. A variety of aluminum tubing was tested in ANSYS, until the lowest weight and most cost effective tubing construction was found that would not deform. The placement of the cross braces for the arm was iteratively determined using ANSYS. Parts were created in Pro-Engineer to ensure the range of motion generated met the requirements, and then tested in ANSYS to ensure they would not plastically deform.

Drive  Train   The drive train is a subsystem with a high degree of technical risk associated with its design and construction due to the number of components and parts involved in its construction. In order to determine the type of drive train to move the lunabot, a trade study was performed, comparing the use of a wheel based drive train against that of a tread based system.

Table 6: Drive Train Trade Study Advantages Disadvantages

Tread Drive Train -Large surface area in contact with ground, creating good grip -Minimal chance of getting stuck

-High technical risk -High lost -Takes a lot time to fabricate - Unable to be fully sealed

Wheel Drive Train -Cheap compared to treads -Low level of technical risk -Less components than treads -Less labor-hours to construct than

-Less grip than treads -Potential for multiple wheels to loose grip of regolith surface

treads -All moving parts can be fully protected

It was decided that a four wheel drive train was preferable to the tread system due to the

budgetary and schedule limitations of the team. To overcome the potential problems of gripping the regolith surface of the field, 10 inch diameter solid tires were chosen as part of a four wheel drive train, that allow the robot more surface area to grip the field surface. In order to minimize drive train costs, CIM motors and Victor Motor Controllers were recycled from older senior design project, allowing funding to be directed towards other purchases. CIM motors by themselves have a high rate of revolution, but did not provide sufficient torque and horse power to power the drive train in a reliable manner. To adjust the output of the motors, gearbox systems were implemented to adjust the output to the wheels. The calculations for the gearing ratios were made using a free Excel calculation tool, to create gearing for the robot to travel at a velocity of 9 ft/s.

After the construction of the gearboxes, the drive train consisted of two CIM motors attached to the two gearboxes using a fixed joint. The gears were engaged using a revolute joint. Each gearbox interfaced with the frame by fixed joint and the gear train rotated a sprocket using a revolute joint. This turned a chain under tension which rotated two wheels affixed to the frame by revolute joints that also possessed sprockets. This independent double sided drive train is commonly known as a tank steering system, and allows the lunabot to individually rotate the two wheels on each side of the robot at different velocities and in different directions, creating the advantages of a small turning radius and high level of motion control.

Electronics   All of the mechanical sub-systems rely on the electronics system to direct and regulate the motions of the motors that power them. The electronics sub-system is the compilation of the components included on the robot that regulate the motion of the mechanical by powering and controlling them and the camera that serves as the video feedback system. The electronics are controlled by the user controls through the use of a wireless XBee transmitter and receiver. Commands received by the receiver are processed by the Arduino Mega 2560 which utilizes the motor controllers to regulate the power to the motors and linear actuators, effectively controlling their motion. As a safety measure, an emergency kill switch is positioned on the frame to immediately cut power to the robot in the event of an emergency.

Figure 6: Electronics Function Diagram

The electronics sub-system was designed to minimize the use of power and data by minimizing the use of components. The data transmission was further reduced by simplifying the complexity of the code transmitted to the robot. Costs were minimized by recycling Victor speed controllers to regulate the CIM motors. Each victor requires a 3-wire PWM input where the nominal voltage for these speed controllers is 12 Volts. The linear actuators are controlled by a VNH2SP30 high-power motor driver, which uses PWM input to control the direction of the linear actuator. These motor drivers also have the ability to send potentiometer data to the user by means of the Arduino Mega using the wireless XBee system.

User  Controls  Due to the competition rules stating the driver must remotely operate the robot from a

room away from the Lunarena competition the driver controls were developed to use Wi-Fi to serially transmit data using a set of XBee Wi-Fi modules.

The Arduino Uno functions as the microprocessor for the driver control interface. Inputs from joysticks and various buttons control the actions of the robot. The driver will have the ability to control the motion of the robot’s drive train using two joysticks, each controlling one of the two motors, mounted on opposite sides of the frame. Buttons control the adjustment of the angle of the arm and the angle of the bucket. Additional presets will be set up to move the arm and bucket to preset configurations.

Coding/Programming   The coding required to control the robot, uses two microcontroller scripts, one for the Arduino Mega and one for the Arduino Uno. Both programs are coded using Arduino code are streamlined to minimize the data transfer between the user controls and the robot. The coding on the Arduino Uno takes the user inputs and translates them into instructions which are serially transmitted across the wireless network to the Arduino Mega. The Arduino Mega’s coding

interprets the inputs sent across the network and performs an output action, allowing the robot to properly function.

Production  and  Construction   After the completion of the detailed design phase, the formal specifications for subsystems and components were outlined and materials were ordered. The tasks required to construct the subsystems, assemble the system, and test the system were identified and scheduled in order of prerequisites. Each of the tasks was assigned to a team member to evenly distribute the work load.

Design  Margins   During the construction process, the mechanical sub-systems were completed in the on campus machine shop, by first constructing required parts and modifying purchased components for the various sub-systems until a sub-assembly could be created. Part dimensions were listed in technical drawings based off CAD models. Each part and assembly had a specific drawing associated with it documenting dimensions and tolerances. The tolerances for the on campus machine shop equipment are ±.002 in, which was the basis for the tolerances of all moving mechanical components. Parts requiring welding, or parts that did not move, but were required to be of a certain minimum or maximum size were manufactured within ±.01 in. The low manufacturing tolerances for the moving parts and components ensure that the mechanical system interfaces have tighter fits, decreasing potential buildup of vibrations, which in turn increases the reliability of the of the lunabot.

Testing  Throughout the design process, ANSYS and Pro Engineer were used to verify the

adequacy of material selections and part dimensions. The majority of physical systems tests were performed during the construction/production phase of the systems life cycle. Testing was an important part of the construction/production design process, as it allowed for verification that parts and components were made within spec and that sub-systems functioned properly, which is crucial for ensuring system reliability.

Functionality of each subsystem was verified through physical testing. The bucket’s volumetric capacity was measured by filling it with known volumes of flour, also indicating any potential leaks. The proper dumping angle was then tested by measuring the angle of the bucket relative to the floor at which all the visible flour was no longer present in the bucket. After confirming the volumetric capacity and dumping angle, the bucket was affixed to the arm, where the ranges of motion of the arm and bucket were tested. The electronics were tested by manually running power to the various devices to ensure they worked, and then iteratively tested with the Arduino programming. Before installing the XBees, serial communications were tested using a tether between the two Arduinos. The communication between the robot and user electronics then was tested and fine-tuned by sending user inputs across the Wi-Fi network. After the electronics and user controls were proven functional. After the robot was assembled, the combined systems were tested to ensure the entire robot was functional.

Operation  Use  and  System  Support   Upon competition of the robot construction and testing procedures, maintenance procedures were established and practiced, to ensure to team was familiarized how to disassemble, repair, and assemble the lunabot system. Spare parts were also created out of remaining materials or purchased. The spare parts, in combination with the maintenance procedures, will ensure the reliability of the robot during competition. In addition, the robot users gained experience controlling the robot on a practice playing field to become familiar with the controls and develop strategies to maximize their performance. Factors such as excavation patterns, were tested to see what would yield the highest rate of material excavation

Retirement   After the completion of the 2012 NASA Lunabotics Competition, the system will be deactivated and placed on display in the Florida Institute of Technology Olin Engineering Complex senior design display room, until a senior design team or the Florida Institute of Technology Robotics team formalizes plans to compete in a subsequent competition. The deactivation process will consist of first cleaning the robot to remove any excess dirt, then removing the battery and locking the wheels, arm, and bucket joints in a stationary position to prevent the robot from moving. The system’s physical components, CAD drawings, and supporting documents will be given to the team to allow for parts harvesting. In addition to physical component recycling, the system’s supporting documents will allow subsequent teams to improve upon any of the robot component designs, allowing for component optimization for subsequent competitions, reducing labor and maximizing a new system’s performance.

Section  4:  Objectives  The table below summarizes the SPEC A and SPEC B requirements, which serves as the

design objectives for the senior design project

Table 7: SPEC A and SPEC B Requirements Summary Table 2.0 The robot will conform to the construction constraints listed in the in the 2012 NASA

Lunabotics Competition Manual 2.0.1 The robot will be designed to be less than or equal to the maximum allowed height,

width, length, and mass, as listed in the 2012 NASA Lunabotics Competition Manual 2.0.2 The robot will have an electronics system that passes inspection and is equipped with a

kill switch 2.1 Threshold: The robot will complete the required outlined competition objectives

Objective: The robot will complete the required objectives and place within the top forty teams

2.1.1 The robot will use one or more 12 V batteries and power distribution system that allows it to function for at least 20 minutes

2.1.2 Threshold: The robot will be able to consistently excavate at least 10 kg of regolith in 10 minutes Objective: The robot will be able to consistently excavate at least 35 kg of regolith in 10 minutes

2.1.3 The robot will be able to excavate regolith and transport it to the designated collection bin

using an arm and front loader bucket 2.1.3.1 The front loader bucket will be connected to the arm by means of revolute joints 2.1.3.2 The arm will be connected to the chassis by means of revolute joints 2.1.3.3 The bucket design will be optimized to maximize the rate of excavation 2.1.3.3.1 The bucket will be designed to contain at least 40 kg of regolith at any given time 2.1.3.4 The front loader bucket with have an adjustable an adjustable angle of attack (AOA) and

height 2.1.3.4.1 The bucket angle of attack will be adjustable by means of two linear actuators 2.1.3.4.2 The arm will adjust the height of the bucket by means of two linear actuators 2.1.3.4.3 The bucket’s height will be adjustable to allow robot to fit in startup dimension constraint 2.1.3.4.4 The bucket will be adjustable to have at least four function configurations 2.1.3.4.4.1 The bucket will have a startup configuration, so robot will fit inside start up dimension

constraints 2.1.3.4.4.2 The robot will have a configuration to excavate lunar simulant 2.1.3.4.4.3 The robot will have a configuration to transport excavated lunar simulant that minimizes

loss of material 2.1.3.4.4.4 The robot will have a configuration to dump excavated lunar simulant into the designate

collection bin 2.1.4 The robot will utilize a wheel based drive train 2.1.4.1 The drive train will allow the robot to pass over potential obstacles placed in the field 2.1.4.2 The drive train will make use of at least four wheels 2.1.4.3 The drive train will allow the robot to travel at a velocity of at least 2.13 m/s 2.1.4.4 The drive train will be mounted to the chassis 2.1.5 The robot sub-systems will be housed within a rigid chassis 2.1.5.1 The chassis will be designed to survive the force of the robot tipping on any of its sides

without failure, and prevent damage to sub-systems 2.1.5.2 The chassis will be powder coated to prevent oxidization 2.1.5.3 The chassis will be visually interesting 2.1.5.4 The arrangement of sub-systems within the chassis will be designed to minimize potential

tipping moments 2.1.5.4.1 The robot will have a center of mass that rests at a low height relative to the field 2.1.5.4.2 The robots will have a center of mass that is centralized within the robot chassis 2.2 The robot will be constructed, programmed, and controlled by means which allow it to

be operated in a safe manner 2.2.1 Threshold: The robot will be remotely operable by one or more users

Objective: The robot will have autonomous capabilities, with user overrides 2.2.2 The user will have the ability to remotely deactivate the robot at any given time 2.2.3 The robot will have its mechanical and electronic components enclosed to prevent utilize

mechanical and electronic failures from lunar simulant 2.2.4 The robot will be able to utilize a camera to relay visual information about the robot’s

position and configuration on the field to the user/s operating it, if necessary 2.2.4.1 The shielding will be minimal in weight 2.2.4.2 The shielding will be affixed to the chassis 2.3 The robot design will be feasible for construction within the allotted schedule and budget 2.3.1 The robot will be designed for construction within a 1.5 semester timeframe

2.3.1.1 The robot will maximize the use of a modular design to simplify construction 2.3.2 The robot will be constructible within a budget of no greater than $10,000 2.3.2.1 The robot construction will maximize the use of standardized components 2.3.2.2 The robot construction will maximize the percentage use of ordered raw materials 2.4 The robot design will utilize optimization techniques to maximize robot functionality and

minimize mass 2.5 The robot will have a sustainable and maintainable design 2.5.1 The robot will utilize scrap and reclaimed materials and components where applicable 2.5.2 The robot will be designed for disassembly for component reuse by future teams 2.5.3 The robot will be disassembled for maintenance after use

Section  5:  Methods/Tasks   The methods identified in the proposed approach were implemented by through the assigning of tasks to the Lunabotics team members, seen in the following tasks list:

Task  Group   Sub  Task  Start  Date   End  Date   Status   Allison  

Metzger  Jennifer  Mori  

Matthew  Goldstein  

Michelle  Little  

Rafi  Ahmed  

Brittany  Essink  

Systems  Engineering  

Paper   Paper  Outline  1/9/2012   1/13/2012   DONE  

        X              

   Locate  Systems  Engineer  to  review  documents  

1/9/2012   2/3/2012               X              

    First  Paper  Draft   1/13/2012   2/3/2012   DONE           X                   First  Paper  Review   2/6/2012   2/10/2012   DONE           X              

    Second  Paper  Review   3/5/2012   3/9/2012   DONE           X                   Third  Paper  Review   4/2/2012   4/6/2012   Done   X   X   X   X   X   X  

    Paper  Submission   4/9/2012   4/13/2012       X                      

                                           Youth  

Outreach  Program  

Contact  scout  groups  about  program  insterest  

1/13/2012   1/18/2012   DONE  

                       

   Research  Scout  badges  focusing  on  science  

1/13/2012   2/2/2012   DONE               X          

   

Create  teaching  plan  focusing  on  specific  age  groups  

1/13/2012   2/2/2012   DONE               X          

   

Creat  powerpoint  demonstrating  engineering/robotics/lunar  

1/23/2012   3/2/2012   DONE               X          

    Order  materials     2/1/2012   3/2/2012   DONE   X           X          

   Reserve  room  on  campus  for  program  

2/2/2012   2/2/2012   DONE  X           X          

   

Run  programs  for  approximately  60  4th  and  5th  grade  students  

2/25/2012   3/18/2012   Done  X   X   X   X   X   X  

    Write  summary  of  program     2/27/2012   4/1/2012   30%               X          

   Submit  PDF  of  program  and  summary  to  Lunabotics    

3/23/2012   4/23/2012      X                      

                                           

Bucket   Update  Drawings  in  CDR   1/9/2012   1/27/2012   DONE           X              

   Update  Bucket  Drawing  in  CAD  

1/9/2012   1/13/2012   DONE                   X           Order  Mounting  Bracket   1/9/2012   2/3/2012   DONE   X                      

   Cut  bucket  main  length  piece  

1/17/2012   1/19/2012   DONE           X              

   Send  off  pieces  of  bucket  to  get  rolled  

1/19/2012   1/24/2012   DONE  X                      

   

Determine  Bucket  Angle  of  Attack  to  maximize  granular  flow  

1/23/2012   1/27/2012   Done           X       X      

    Build  bucket  sides   1/24/2012   1/26/2012   DONE           X              

    Weld  Bucket   1/26/2012   1/31/2012   DONE                               Attach  Bucket  Mounts   2/2/2012   2/21/2012   70%           X           X  

    Weigh  Bucket  Assembly   2/5/2012   2/15/2012   DONE           X           X  

   make  bucket  out  of  carbon  fiber  

2/10/2012   2/12/2013   DONE                       X  

                                           Frame  Structure   Modify  CAD  Frame  Design  

1/9/2012   1/16/2012   DONE                   X      

   Measure  and  Cut  2x1  Al  Tubing  

1/17/2012   1/26/2012   DONE   X   X                  

   Drill  all  mounting  holes  for  tubing  

1/17/2012   1/27/2012   DONE   X   X                       Press  Bearings  into  frame   1/17/2012   2/24/2012   done   X   X                  

    Weld  Frame   1/24/2012   1/31/2012   DONE                                                                      

Drive  Train  Design  bracket  for  wheel  hub  

1/9/2012   2/9/2012   DONE                   X      

   Build  Gearbox  for  Drive  Train  

1/24/2012   2/21/2012   30%               X   X   X       Mount  Gearbox  to  Frame   2/9/2012   2/23/2012                   X       X  

   Manufacture  Wheel  Hub  Bracket  

2/9/2012   2/16/2012   80%                          

   

Assemble  Drive  Train  (sprockets,  chain,  wheels,  bearings,  shafts,)  

2/14/2012   2/23/2012   30%  X   X       X   X   X  

    Mount  Wheel  Hub  Bracket   2/21/2012   2/28/2012   40%               X   X      

                                           

Arm   Modify  Arm  Design  in  CAD   1/9/2012   1/17/2012   DONE                   X      

   Design  Brackets  for  Mounting  Linear  Actuator  

1/9/2012   2/9/2012   DONE           X       X      

   Measure  and  cut  Arm  structure  

1/17/2012   1/26/2012   DONE   X           X          

    Weld  arm  structure   1/24/2012   1/31/2012   DONE                          

   Press  Bearings  and  placings  Shafts  into  Arm  Structure  

2/7/2012   2/16/2012   DONE  X           X          

   Manufacture  Mounting  Brakcets  

2/9/2012   2/16/2012   DONE                          

    Mount  Linear  Actuator   2/21/2012   2/28/2012   95%   X   X   X   X   X      

                                           Electronics   Design  wiring  diagram   1/9/2012   1/16/2012   DONE                          

   Confirm  validity  of  Xbee  Wifi  

1/12/2012   1/19/2012   DONE       X                  

   Determine  total  required  current  

1/12/2012   1/27/2012   DONE       X                       Order  battery   1/12/2012   1/28/2012   DONE   X                      

    Order  parts     1/16/2012   1/29/2012   DONE   X                      

   Programming/wiring  for  nunchucks  

1/19/2012   2/26/2012   80%       X               X  

   Wire/program  speed  controllers/motor  

2/2/2012   2/26/2012   90%       X               X  

   Wire/program    linear  actuator  control  

2/2/2012   2/20/2012   DONE       X               X  

   Test  and  modify  drive  train  speed  control  

2/9/2012   3/1/2012   DONE       X               X  

   Test  and  modify  arm  controls  

2/16/2012   3/26/2012   75%       X               X       Connect  Xbee  wifi   3/1/2012   3/26/2012           X               X  

   Install  emergency  off  buttons  

3/1/2012   3/26/2012           X               X  

   Test  and  modify  wireless  connection  to  robot  

3/27/2012   4/5/2012           X               X  

   Get  feedback  from  potentiometers  

3/28/2012   4/6/2012                                   Test  Victors   2/9/2012   2/13/2012   DONE       X               X  

    Test  Motors   2/9/2012   2/13/2012   DONE       X               X                                              Powder  coating   Powder  Coating  the  robot  

2/6/2012   2/15/2012   done  X                      

                                           

Assembly   Attach  Arm  to  Frame   2/23/2012   3/8/2012   90%   X   X   X   X   X   X       Attach  Bucket  to  Arm   2/23/2012   3/8/2012   60%   X   X   X   X   X   X  

    Attach  Electronics  to  Frame   3/8/2012   3/29/2012       X   X   X   X   X   X  

                                           

Testing  Test  and  modify  whole  robot    

4/1/2012           X   X   X   X   X   X  

Section  6:  Results  

Requirements  Flowdown  Checklist    

CDD SRD Verification process 1.0 2.0 Physical model weighted and measured 1.0.1 2.0.1 1.0.2 2.0.2 Electronics system, user controls, and programming testing 1.1 2.1 Lunabot system testing 1.1.1 2.1.1 Electronics system testing 1.1.2 2.1.2 Lunabot system testing and excavation rate testing

1.1.2 1.1.3

2.1.3 Lunabot system testing, arm and bucket testing 2.1.3.1 Physical construction parameter, range of motion testing 2.1.3.2 Physical construction parameter, range of motion testing

1.1.2 1.1.3

2.1.3.3 Bucket optimization script 2.1.3.3.1 Bucket optimization script constraint 2.1.3.4 Physical construction parameter, range of motion testing 2.1.3.4.1 Bucket range of motion testing 2.1.3.4.2 Arm range of motion testing 2.1.3.4.3

Testing lunabot system preset configurations

2.1.3.4.4 2.1.3.4.4.1 2.1.3.4.4.2 2.1.3.4.4.3 2.1.3.4.4.4

1.1.2 1.1.3

2.1.4 Physical design parameter 2.1.4.1 Lunabot system testing 2.1.4.2 Physical design parameter 2.1.4.3 Drive train testing 2.1.4.4 Physical design parameter

1.1.2 1.1.3

2.1.5 2.1.5.1 ANSYS stress testing 2.1.5.2 Physical design parameter 2.1.5.3 Peer review of robot aesthetics 2.1.5.4

CAD center of mass simulation 2.1.5.4.1 2.1.5.4.2

1.0 1.2

2.2 Physical design parameters, sub-system testing 2.2.1 Electronics testing, lunabot system testing 2.2.2 2.2.3 Physical design parameters, gap testing of shielding 2.2.4 Physical design parameters, electronics testing

1.2 2.2.4.1 Physical design parameters, weight assemblage

1.4 2.2.4.2 Physical design parameters 1.2 2.3 WBS, BOM, risk mitigation strategy implementation

1.3 2.3.1 WBS 2.3.1.1 Design parameter 2.3.2 BOM

1.1.3 2.3.2.1 BOM 1.3.2 2.3.2.2 BOM 1.4 2.4 WBS

1.3.3 1.5

2.5 Physical design parameters 2.5.1 Checking machine shop scrap shed for available materials 2.5.2 Physical design parameters, maintenance procedure creation 2.5.3

Section  7:  Conclusions/Recommendations  

Future  Design  Improvements   During the system’s life cycle, the system was designed with limited time and resources, preventing all subsystems and components of the system from being optimized. While the designs provided for a robot with a high potential for performance, there are subsystems that can be improved to optimize future Lunabotics Competition robots. The following is a list of potential optimization design projects that were identified, but which were not able to be optimized within the given time frame:

§   Minimization of electrical power consumption and maximization of system response time by simplification of electrical system and streamlining of microcontroller coding

§   Optimization of arm design to improve maximum quantity of excavated regolith per trip §   Tubing path and material selection for optimized frame design §   Design of suspension for wheel based drive train to improve system’s ability to handle

obstacles

Section  8:  References  

Referenced  Sources  [1] Optimization of Bucket Design for Underground Loaders, Master’s Thesis, Jonas Helgesson, Department of Product & Production Development, Chalmers University of Technology Sweden 2010

Additional  Sources  1.   http://www.nasa.gov/offices/education/centers/kennedy/technology/lunabotics.html 2.   http://ares.jsc.nasa.gov/humanexplore/exploration/exlibrary/docs/isru/06energy.htm

3.   http://www.usfirst.org/roboticsprograms/frc/content.aspx?id=478 4.   http://ieeexplore.ieee.org.portal.lib.fit.edu/stamp/stamp.jsp?tp=&arnumber=4839304 5.   http://www.lockheedmartin.com/products/MarsGlobalSurveyor/index.html 6.   www.google.com images (Lunabotics mining competition 2010) 7.   http://ieeexplore.ieee.org.portal.lib.fit.edu/stamp/stamp.jsp?tp=&arnumber=4839303&isn

umber=4839294 8.   http://ieeexplore.ieee.org.portal.lib.fit.edu/stamp/stamp.jsp?tp=&arnumber=5354067&isn

umber=5353884F 9.   Iizuka, K.; Kunii, Y.; Kubota, T.; , "Study on wheeled forms of lunar robots for

traversing soft terrain," Intelligent Robots and Systems, 2008. IROS 2008. IEEE/RSJ International Conference on , vol., no., pp.2010-2015, 22-26 Sept. 2008 doi: 10.1109/IROS.2008.4651219 URL: http://ieeexplore.ieee.org.portal.lib.fit.edu/stamp/stamp.jsp?tp=&arnumber=4651219&isnumber=4650570

10.   Nishida, S.-I.; Wakabayashi, S.; , "A mobility system for lunar rough terrain," ICCAS-SICE, 2009 , vol., no., pp.4716-4721, 18-21 Aug. 2009 URL: http://ieeexplore.ieee.org.portal.lib.fit.edu/stamp/stamp.jsp?tp=&arnumber=5334340&isnumber=5332438

11.   http://www.newscientist.com/article/dn18001-500000-treasure-dug-up-in-lunar-soil.html 12.   http://www.teamwaldbaum.com/2009-lunar-regolith-excavator 13.   http://surreylunarrover.wordpress.com/ 14.   http://www.nasa.gov/mission_pages/phoenix/spacecraft/robotic-arm.html 15.   http://www.youtube.com/watch?v=DdPzjjFcUVo 16.   http://www.youtube.com/watch?v=ShREDN8yASA 17.   http://www.trossenrobotics.com/linear-actuators.aspx 18.   Dr. Adrian Peter’s SYS 5310 Course Lecture Slide Show Presentations from Fall of 2010

Appendix:  Team  Member  Contributions  

Allison  Metzger  Presentation and Competition Tasks -Set up weekly team meetings, kept track of team budget, and robot schedule -Helped in the brainstorming sessions for the robot basic design -Part of the teams that researched what parts to order for the robot -Order all robot parts -Pick up robot parts -Order tee shirt -Help design Senior Design Showcase poster -Submitted paper work for Lunabotics (Video, Rule 31, Outreach presentation, team roster ) -Created the power points for the Missile Space and Range and Pioneers Dinners and the National Space Coast Lunch - Presented at all Functions (Dinners, Lunch in, and Girl Scout Community Day) -Assisted in writing Senior Design Final Paper

Manufacturing Tasks frame along with various other components such as the gear box, the regolith proofing shield designs and the wheels -Machined Blocks for robot arm -Cut out robot frame with Michelle -Helped make carbon fiber bucket -Assisted in robot assembly robot assembly (for example: gear box, robot shields, and wheels) -Assisted in design meetings in order to help all components function properly -Helped trouble shoot electronics

Matthew  Goldstein   Systems Engineering and Presentation Tasks -Systems Engineering Paper -All systems engineering figures -Granular flow calculation -Systems engineering presentation -Bucket optimization routine -Testing and design section from CDR -Assisted in final report writing for Senior Design -Section 31 Report -Generated primary judge question list to practice answering questions about lunabot for Senior Design Showcase -Present at all fundraising events Design and Construction Tasks -Creation of electromagnet exercise and electromagnet design in community outreach project -Wheel hub design -Bucket design and construction -Angle of attack determination -Excavation rate calculation -Battery cage design and construction -Control box design and construction -General labor on all parts fabrication

Michelle  Little  For senior design this semester, my main tasks were manufacturing parts in the machine shop, assembling the frame along with various other components such as the gear box, the regolith proofing shield designs and the wheels. I also organized the entire outreach program which consisted of working with the Girl Scouts of Citrus Council to register the girls for the program, reserve a room on campus (which proved harder than I thought), research and develop activities for the event, prepare a “Women in Engineering” power point, purchase all the materials, and

help to create the patch that was given to the girls. This outreach project also required a five page written paper to be submitted to NASA Lunabotics. I helped to edit the systems engineering paper and went on numerous supply trips during the course of the semester. In addition to the above tasks, I also helped to create the video required as part of the rules for the competition.

 Brittany  Essink    When I joined the team this semester, the frame was made, but wasn't put together, and almost no progress on electronics had been made except for some research on how to use wii nunchucks as joysticks. For the mechanical side of things, in the beginning of the semester, I helped make the carbon fiber bucket at Dr. Reichard's composites company. Throughout the semester I also worked on whatever machining was needed at the time including cutting the steel for the bucket edges, machining hex shafts to the correct length on the lathe, and cutting and gluing acrylic dust protection pieces for the electronics. On the electronics, I worked to get the Victors, DC motors, H-bridges, and actuators all functioning individually. I then worked on the Arduino code to get them working with the microcontrollers, and once that was completed, worked on interfacing with joysticks and buttons. I helped with the serial communication program between the two Arduinos for all motor and actuator control. I got the wireless communication using XBees to work, and then proceeded to help move all the electronics over to solder boards. I assisted in moving all the electronics to the robot, and got it working in time for the senior design showcase. When the solder kept breaking on the boards, I resoldered the wires numerous times, and eventually helped move most of the electronics back to the breadboard in order to make the video. After getting the robot working again in time for the Missileers dinner, I worked to dustproof the robot, perform testing for actual use of the robot in the video, and record the video for submission. In addition to the building and coding, I also helped the team at the Girl Scout outreach event we held for the competition. For the systems engineering paper, I edited and contributed to the document, and submitted it online. I can honestly say that I am very proud of what we have accomplished and I am extremely glad that I joined this team. After finals week/graduation is over, I will continue to work on the robot to move the electronics to a more reliable wiring system for competition, switch to wifi XBees, work with proximity sensors for the obstacle section of the competition, and run the additional testing needed for the robot before the competition.

Rafiuddin  Arif  Ahmed   I was created all of the Pro/E drawings of the robot. This includes the placement of joints, calculations for the gearbox, and machinability of all parts. I made all the machine drawings for the mechanical components of the robot except for the bucket. I helped in coordinating the overall machining of the robot. I was involved with the fabrication and assembly of the mechanical components. I helped out with the community outreach event. I was involved in troubleshooting the final stages of the electronics.

Jennifer  Mori   I started by creating a basic wiring diagram which Brittany improved later. The first electronic system I worked on was the drive train controls with victors and CIM motors. Because victors act like servos in how they are controlled by Pulse Width Modulation, I was able to use a library for servos in the Arduino program. This system was controlled by the y-axis potentiometers in a PC joystick, which Larry helped me to wire. I then mapped the analog in readings from the joysticks to the analog write in the servo library which then controlled the movement of the CIM motors. Next I set up the h-bridges to control the linear actuators, with Brittany’s assistance, and the programmed the Arduino to turn on the pairs of actuators together while a button was pressed. I programmed the Arduino so that two smaller actuators are controlled by the pink buttons while the larger ones are controlled by the blue buttons. I have a plan to create two presets for the arm; one will set the arm to the starting position while the other will move it to the dumping position. The next step we took was to separate the controls from the robot’s system. To do this we used serial communication between the Arduino Pro Mini and the Arduino Mega 2560. I had no prior experience with serial communication, so a graduate student helped me to understand the process I needed to go though to make the communication work. Once the controls were successfully separated from the on-board electronics, we were able to replace the tether with Arduino shields and XBEEs for wireless communication. It took patience, but Brittany and I were successful in upgrading our Lunabot to run wirelessly. Once we knew the systems worked as we had planned, we transferred the electronics to solder boards. I worked on the board that holds the h-bridges while Brittany did the other one. We also spend about an equal amount of time fixing the solder joints that broke and stripping then crimping wires.