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Robotics Chapter 1 - Introduction. Dr. Amit Goradia. Topics. Introduction – 2 hrs Coordinate transformations – 6 hrs Forward Kinematics - 6 hrs Inverse Kinematics -6 hrs Velocity Kinematics - 2 hrs Trajectory Planning - 6 hrs Robot Dynamics (Introduction) - 2 hrs - PowerPoint PPT Presentation
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RoboticsChapter 1 - Introduction
Dr. Amit Goradia
Topics
• Introduction – 2 hrs• Coordinate transformations – 6 hrs• Forward Kinematics - 6 hrs• Inverse Kinematics - 6 hrs• Velocity Kinematics - 2 hrs• Trajectory Planning - 6 hrs• Robot Dynamics (Introduction) - 2 hrs• Force Control (Introduction) - 1 hrs• Task Planning - 6 hrs
Introduction
• Definition (Robot Institute of America):– A robot is a programmable
multifunction manipulator designed to move material, parts, tools, or specialized devices through variable programmed motions for the performance of a variety of tasks.
Puma 560 Robot used for inspection
Types of Robots
• Stationary
• Mobile – Ground– Wheeled– Tracks– Legs
• Mobile – Underwater
• Mobile – Aerial
• Microgravity (Space)Honda ASIMO
Robot Types - Stationary
Puma 560 Arm
ABB Arm
MSU Microbot
Mobile
MSUMobileManipulatorResearch Platform (R2-D2) Stanford’s Stanley
(First winner of DARPA Grand Challenge)
MSUMicro Crawler
Sony’sQRIO
Space
Canada ArmOn InternationalSpace Station
Sojourner-First Mars Rover (1998)
JPL’sPioneerSpace Probe
ISRO’sChandrayaan -1
Brief History• 1921 – Word robot derived from a Czech play• 1940s – Teleoperator developed at Oak Ridge national
Labs• 1954 – George Devol, Programmed articular transfer
device• 1956 – Joe Engelberg, Unimation (first robotics
company)• 1961 – First robot installed on assembly line in GM• 1968 – Japan, Kawasaki makes robots• 1969 – GE makes first walking robot• 1974 – First Hydraulic drive robot, Cinciniti Milacron• 1978 – First Puma Robot (Programmable Universal
Machine for Assembly)
Accuracy, Repeatability and Resolution
• Accuracy:– A measure of how close a
manipulator can come to a given point within its workspace
• Repeatability: – A measure of how close a
manipulator can return to a previously taught point
• Resolution (Precision): – The smallest increment of
motion that can be sensed (executed). It is a function of distance traveled and the number of bits of encoder accuracy.
A B
Resolution
Actual DesiredPosition
Accuracy
Robot Specifications• Joint Variable (joint):
– Relative displacement between adjacent links. Can be revolute or prismatic.
• End effector:– Gripper or tool used to perform the robots tasks.
• Degree of freedom (DOF)– Number of joints (DOF > 6 implies redundant robot)
• Configuration:– Determines the location of every point on the manipulator (not just the
end effector).• Configuration Space
– The set of all possible configurations• Workspace (work envelope):
– Total volume spread out by the end effector as the manipulator executes all possible motions
• Accuracy, Repeatability and Resolution• Speed and Acceleration (min and max)• Payload Capacity
Typical Robot Specifications
• Hydraulic or Electric• Payload capacity
– 50 – 100 Kgs (Hydraulic)– 1 – 25 Kgs (Electric)
• Degrees of freedom: 4 to 7 based on application• Repeatablity
– ± 1 mm – 1.5mm (Hydraulic)– ± 0.05mm – 0.01mm (Electric)
• Cost– $80,000 - $200,000 (Hydraulic)– $40,000 – $100,000 (Electric)
Robotic System Architecture
• Components– Mechanical structure– Drives
• Electric• Hydraulic• Pneumatic
– Computing and Control– Sensors
• Encoders• Force• Vision• many more
– Communication• CAN, ethernet, Wireless,
Serial link (RS232), USB, analog link, PROFIBus, GPIB, and many more
Environment Sensors
Planner
Controller DrivesMechanicalStructure
ConfigurationSensor
World spaceOutput
Computer
Common Robot Configurations
• Joint types– Revolute– Prismatic
• Revolute joints (R)– Compact– Increased dexterity – easier to
maneuver around obstacles– Large kinematic and dynamic
coupling between links– Larger error accumulation – Difficult control problem
• Prismatic joints (P)– Increased accuracy– Higher payload– Difficult to integrate– Require more volume
Cartesian Configuration
• PPP– First three joints are
prismatic
• Features– High resolution– High accuracy– High payload capacity– More volume needed for
motion– Difficult to integrate with
other machines– Uniform resolution
Epson Cartesian Arm
Reachable Workspace
Cylindrical Configuration
• RPP– One revolute joint– Two linear joints
• Joint coordinates map to cylindrical coordinates– r, θ, z
• Non-uniform precision– Horizontal precision highest
along inside edge of work envelope
Reachable Workspace
Denso Cylindrical arm
Spherical Configuration
• RRP– Two revolute joints– One prismatic joint
• Joint variables directly correspond to spherical coordinates– φ – θ – r
Reachable Workspace
Articulated Configuration
• RRR– Three revolute joints
• Features– Light payload capacity– Lower accuracy– Easy to integrate with
other manipulators
SCARA Configuration
• Selective Compliant Articulated Robot for Assembly (SCARA)
• RRP– Two revolute– One prismatic
• Introduced in 1979• Revolutionized
manufacturing of small electronics
Reachable Workspace
Basic Research Issues
• Effectors and Mobility– Autonomous Flight– Fish Robots– Legged Motion– Artificial Muscles– Drives
• Sensors– Vision– Force / Haptic– Communication– Encoder
• Control Systems– Behaviour control– Networked control– Active vibration control– Hyper redundant
robotic systems
• Task Planning– Understanding the real
world– Failsafe planning to
work in the real world
Robot Programming
• Motion based– RCCL– RAPID– VAL++
• Task / Goal based– Behavior Language– PRS (Procedural Reasoning
System)
• Intermediate level– Combines aspects of low level
motion based and high level task based
– FRP (Functional Reactive Programming)
– FROB (Functional Robotics)