Robotics Chapter 1 - Introduction

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31 Οκτ 2013 (πριν από 3 χρόνια και 5 μήνες)

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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


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

MSU

Mobile

Manipulator

Research

Platform

(R2
-
D2)

Stanford’s Stanley

(First winner of DARPA Grand Challenge)

MSU

Micro

Crawler

Sony’s

QRIO

Space

Canada Arm

On International

Space Station

Sojourner

-
First Mars

Rover

(1998)

JPL’s

Pioneer

Space Probe

ISRO’s

Chandrayaan
-
1

Robot


Mechanical Structure

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 Desired

Position

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

Drives

Mechanical

Structure

Configuration

Sensor

World space

Output

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)