P09204: Second Generation Design

Team Members:Jason JackNandini VemuriJeff HoweJohn CorletoEmily PhillipsRyan Schmitt

Build a control system to command interchangeable motor modules

Control system must be: Open-Source, Open-Architecture Modular Scalable, Programmable

Control system must be controllable by payload or Windows/Linux PC

System must be smaller than previous units

Decade size reduction Microcontroller within

control system assembly Fully documented,

seamless handoff Reusable GUI Expandable system

design Minimum 1-hour battery

life, separate supplies

Motors must be efficient, easily controlled, cheap, widely available

Battery must be smaller, lighter Power Distribution needs to be more

robust than previous teams implementation

Software Implementation must exercise all hardware capabilities

Wireless datalink must have minimum range of 100 ft.

Selection CriteriaSegmentWeight

  A     B     C                     Freescale     BDMicro     Arduino Nano  

Rating Notes Wtd Rating Notes Wtd Rating Notes WtdSpeed 5% 3 16MHz 0.15 3 16MHz 0.15 3 16MHz 0.15

Memory 20% 2 2KB 0.40 3 4KB 0.60 1 1KB 0.20Open Source 15% 1 Closed Source 0.15 3 avr-gcc 0.45 3 Open Source 0.45

IDE Flexibility 15% 1 Code Warrior 0.15 3 Use Anything 0.45 3 Use Anything 0.45Small Size 20% 1 Not Small 0.20 2 Small 0.40 3 NANO! 0.60

Existing Code Base 10% 3Expansive Libraries 0.30 3

Open Source Fully Modular Driver Base 0.30 2 Arduino Libraries 0.20

Expandable Memory 10% 3

8-bit Mem Interface 0.30 2 X-RAM Interface 0.20 1 Nothing 0.10

Experience 5% 3 CE Experience 0.15 2Easy Learning

Curve 0.10 1None have used Arduino

Architecture 0.05Total Score   1.80     2.65     2.20  

Rank   1     3     2  

  DC/Servo DC/DC Stepper/Stepper DC/StepperCost 4 2 1 3

External Circuitry 4 1 2 3

Design ComplexitySoftware 2 3 4 1Hardware 4 1 2 3

Efficiency 3 4 1 2Research Required 1 2 4 3

Scalability 3 1 4 2

Stall TorqueDrive 1 3 4 2Steer 4 4 3 4Total:  26 21 25 23Rank:  4 1 3 2

  Best WorstCell Ranks: 4 1

Microcontroller did not have the capacity to generate all necessary control signals

Stepper motor drivers had non-deterministic behavior, required excessive control signals

Crossbow Wireless had confusing, custom programming; too complex for design

Errors in PCB design post-fabrication mandated changes late in development cycle

Power Distribution – Logic and Motor Motors – DC and Servo Microcontroller – BDMicro Atmel

ATmega128 GUI – Continuous and Incremental Control Operational Software – Command Protocol PID controller – Arduino Nano Wireless – IOGear Bluetooth Serial Adapter

Single Unit: $866.50 $866.50 per unit

Lot of 10: $6021.50 $602.15 per unit

Lot of 100: $56980.37 $569.80 per unit

Lot of 1000: $558609.46 $555.61 per unit

The per unit price drops dramatically between a single unit cost and a lot of 10, however due to COTS fixed costs there is not much benefit for purchasing in larger lots than this

Merge power suppliesRedesign power supplies to use

isolated switching supplies (isolate motor spikes from logic)

Merge microcontrollersMerge DC DriversFurther research into PCB

manufacturing, reduce costsReduce cabling, merge headers

Light seeking plant carrier “Birds-eye-view” robotic Pacman game Robot “battle” competition Robot dance competition Autonomous, mobile paintball sentry

robot Software engineering project, further

GUI development Electrical engineering project, improve

electrical systems design