Modeling and Control of Robot Manipulators

Jianbo Su

Department of Automation

Email: jbsu@sjtu.edu.cn

Tel: 34204276

Lecture 1: Introduction

Robotics Robotics （机器人学）（机器人学）

Industrial Robot Industrial Robot （工业机器人）（工业机器人）

Modeling and Control of Robot Manipulators Modeling and Control of Robot Manipulators

（机器人操作手的建模与控制）（机器人操作手的建模与控制）

Robotics

History of RoboticsHistory of Robotics

General Framework of RoboticsGeneral Framework of Robotics

Classification of RobotClassification of Robot

History of Robotics

The word "Robot" comes from the 1921 play "The word "Robot" comes from the 1921 play "

R.U.R." by the Czech writer Karel Capek (pronR.U.R." by the Czech writer Karel Capek (pron

ounced "chop'ek").  "Robot" comes from the Czounced "chop'ek").  "Robot" comes from the Cz

ech word "robota", meaning "forced labor." ech word "robota", meaning "forced labor." 

The word "robotics" also comes from science fThe word "robotics" also comes from science f

iction - "Runaround" (1942) by Isaac Asimov. iction - "Runaround" (1942) by Isaac Asimov. 

Three Laws of Robotics:Three Laws of Robotics: * Law Zero: A robot may not injure humanity, or, through * Law Zero: A robot may not injure humanity, or, through inaction, allow humanity to come to harm. inaction, allow humanity to come to harm. * Law One: A robot may not injure a human being, or, through * Law One: A robot may not injure a human being, or, through inaction, allow a human being to come to harm, unless this inaction, allow a human being to come to harm, unless this would violate a higher order law. would violate a higher order law. * Law Two: A robot must obey orders given it by human beings, * Law Two: A robot must obey orders given it by human beings, except where such orders would conflict with a higher order law. except where such orders would conflict with a higher order law. * Law Three: A robot must protect its own existence as long as * Law Three: A robot must protect its own existence as long as such protection does not conflict with a higher order law.such protection does not conflict with a higher order law.

History of Robotics

History of Robotics

early robots (1940's - 50's) Grey Walter's "Elsie the tortoise"

"Shakey" Stanford Research Institute in the 1960s. 

The General Electric Walking Truck the first legged vehicle with a computer-brain, by Ralph Moser at General Electric Corp. in the 1960s. 

History of Robotics

The first modern industrial rThe first modern industrial robots were probably the "Uobots were probably the "Unimates", created by Georgnimates", created by George Devol and Joe Engleberge Devol and Joe Engleberger in the 1950's and 60's.  Eer in the 1950's and 60's.  Engleberger started the first rngleberger started the first robotics company, called "Uobotics company, called "Unimation", and has been calnimation", and has been called the "father of robotics."led the "father of robotics."

Isaac Asimov and Joe Engleberger (image from Robotics Society of America web site)

History of Robotics

History of Robotics

EXPLORATION EXPLORATION

  People are interested in places that are People are interested in places that are sometimes full of danger, like outer sometimes full of danger, like outer space, or the deep ocean.  But when they space, or the deep ocean.  But when they can not go there themselves, they make can not go there themselves, they make robots that can go there.  The robots are robots that can go there.  The robots are able to carry cameras and other able to carry cameras and other instruments so that they can collect instruments so that they can collect information and send it back to their information and send it back to their human operatorshuman operators

History of Robotics

INDUSTRY INDUSTRY

When doing a job, robots can do When doing a job, robots can do many things faster than humans.  many things faster than humans.  Robots do not need to be paid, eRobots do not need to be paid, eat, drink, or go to the bathroom liat, drink, or go to the bathroom like people.  They can do repeatatike people.  They can do repeatative work that is absolutely boring tve work that is absolutely boring to people and they will not stop, slo people and they will not stop, slow down, or fall to sleep like a huow down, or fall to sleep like a human.man.

History of Robotics

MEDICINEMEDICINE Sometimes when operating, Sometimes when operating, doctors have to use a robot doctors have to use a robot instead.  A human would not be instead.  A human would not be able to make a hole exactly one able to make a hole exactly one 100th of a inch wide and long.  100th of a inch wide and long.  When making medicines, robots When making medicines, robots can do the job much faster and can do the job much faster and more accurately than a human more accurately than a human can.  Also, a robot can be more can.  Also, a robot can be more delicate than a human.delicate than a human.

History of Robotics

MEDICINEMEDICINE

Some doctors and engineers are also developing prosthetic (bionic) Some doctors and engineers are also developing prosthetic (bionic) limbs that use robotic mechanisms. limbs that use robotic mechanisms. 

History of Robotics

MILITARY and POLICEMILITARY and POLICE Police need certain types of robots for Police need certain types of robots for bomb-disposal and for bringing video bomb-disposal and for bringing video cameras and microphones into dangerous cameras and microphones into dangerous areas, where a human policeman might areas, where a human policeman might get hurt or killed.  The military also uses get hurt or killed.  The military also uses robots for (1) locating and destroying robots for (1) locating and destroying mines on land and in water, (2) entering mines on land and in water, (2) entering enemy bases to gather information, and enemy bases to gather information, and (3) spying on enemy troops.(3) spying on enemy troops.

TOYS TOYS

The new robot technology is making intereThe new robot technology is making interesting types of toys that children will like to sting types of toys that children will like to play with.  One is the "LEGO MINDSTORplay with.  One is the "LEGO MINDSTORMS" robot construction kit.  These kits, whiMS" robot construction kit.  These kits, which were developed by the LEGO company ch were developed by the LEGO company with M.I.T. scientists, let kids create and prwith M.I.T. scientists, let kids create and program their own robots.  Another is "Aibo" ogram their own robots.  Another is "Aibo" - Sony Corporation's robotic dog.- Sony Corporation's robotic dog.

History of Robotics

General Framework of Robotics

RoboticsRobotics is the science studying the is the science studying the intelligent connecintelligent connectiontion of of perceptionperception to to actionaction

• Action: Action: mechanical systemmechanical system (locomotion & manipulation) (locomotion & manipulation)

• Perception: Perception: sensory systemsensory system (proprioceptive & heteroceptive) (proprioceptive & heteroceptive)

• Connection: Connection: control systemcontrol system

Robotics is an Robotics is an interdisciplinaryinterdisciplinary subject concerning subject concerning mechanics, elmechanics, electronics, information theory, automation theory.ectronics, information theory, automation theory.

Classification of Robotics

Advanced RobotsAdvanced Robots

autonomousautonomous execution of missions in execution of missions in unstructured or unstructured or

scarcely unstructuredscarcely unstructured environment environment

Industrial RobotIndustrial Robot

• Class 1: Manual Handling DeviceClass 1: Manual Handling Device

• • Class2: Fixed-Sequence RobotClass2: Fixed-Sequence Robot

• • *Class3: Variable Sequence Robot*Class3: Variable Sequence Robot

• • Class4: Playback RobotClass4: Playback Robot

• • Class5: Numerical Control RobotClass5: Numerical Control Robot

• • *Class6: Intelligent Robot*Class6: Intelligent Robot

JIRA:Japanese Industrial Robot Association RIA: The Robotics Institute of America

Classification of Robotics

• • Type A: Handling Devices with manual controlType A: Handling Devices with manual control

• • Type B: Automatic Handling Devices with predeterminedType B: Automatic Handling Devices with predetermined

cyclescycles

• • Type C: Programmable, servo controlled robotsType C: Programmable, servo controlled robots

• • Type D: Type C with interactive with the environmentType D: Type C with interactive with the environment

AFR: The Association Francaise de Robotique

Classification of Robotics

Industrial Robot

Automation & RobotAutomation & Robot

Definition of Industrial RobotDefinition of Industrial Robot

Application of Industrial RobotApplication of Industrial Robot

Components of Industrial RobotComponents of Industrial Robot

Rigid ( or Fixed ) Automation

• • High initial investment for custom-engineered High initial investment for custom-engineered

equipmentequipment

• • High production ratesHigh production rates

• • Relatively inflexible in accommodating productRelatively inflexible in accommodating product

varietyvariety

Types of Automated Manufacturing Systems

Types of Automated Manufacturing Systems

Programmable AutomationProgrammable Automation

• • High investment in general purpose equipmentHigh investment in general purpose equipment

• • Lower production rates than fixed automationLower production rates than fixed automation

• • Flexibility to deal with variations and changes inFlexibility to deal with variations and changes in

product configurationproduct configuration

• • Most suitable for batch productionMost suitable for batch production

Flexible AutomationFlexible Automation• • High investment for a custom-engineered systemHigh investment for a custom-engineered system

• • Continuous production of variable mixtures ofContinuous production of variable mixtures of

productsproducts

• • Medium Production RatesMedium Production Rates

• • Flexibility to deal with product design variationsFlexibility to deal with product design variations

Types of Automated Manufacturing Systems

Automation Application

Hierarchical Structure of Automation

Definition of an Industrial Robot

A robot is a A robot is a re-programmable multifunctionalre-programmable multifunctional manipulator designed to move material, manipulator designed to move material, parts, tools, or specialized devices through parts, tools, or specialized devices through variable programmed motions for the variable programmed motions for the performance of a variety of tasks.performance of a variety of tasks.

Robot Institute of America

(Group within Society of Manufacturing Engineers)

Industrial Robot Examples

World Supply of RobotsWorld Supply of Robots

World Supply of RobotsWorld Supply of Robots

Material handlingMaterial handling

ManipulationManipulation

MeasurementMeasurement

Typical ApplicationsTypical Applications

Advantages of Robots

• Robotics and automation can, in many situation, increase productivity, safety, efficiency, quality, and consistency of products

• Robots can work in hazardous environments

• Robots need no environmental comfort

• Robots work continuously without any humanity needs and illnesses

• Robots have repeatable precision at all times

• Robots can be much more accurate than humans, they may have mili or micro inch accuracy.

• Robots and their sensors can have capabilities beyond that of humans

• Robots can process multiple stimuli or tasks simultaneously, humans can only one.

• Robots replace human workers who can create economic problems

Current Industrial Robots

are not creative or innovative, are not creative or innovative, no capability to think independently, no capability to think independently, cannot make complicated decisions, cannot make complicated decisions, do not learn from mistakes do not learn from mistakes cannot adapt quickly to changes in their cannot adapt quickly to changes in their

surroundings surroundings

We must depend on real people for these We must depend on real people for these abilities! abilities!

Components of Industrial Robot

Mechanical structure or manipulator Mechanical structure or manipulator （（机构机构 ------ 骨骼，关节）骨骼，关节）

Actuator Actuator （驱动器（驱动器 ------ 肌肉）肌肉） Sensors Sensors （传感器（传感器 ------ 眼睛，皮肤眼睛，皮肤…………）） Control systemControl system （控制系统（控制系统 ------ 大脑）大脑）

Manipulator Structures

Mechanical components Mechanical components

Mechanical configurationsMechanical configurations

Mechanical Components

Robots are serial “chain” mechanisms made up of Robots are serial “chain” mechanisms made up of • ““links”links”（连杆）（连杆） (generally considered to be rigid) (generally considered to be rigid) • ““joints” joints” （关节）（关节） (where relative motion takes place(where relative motion takes place

) ) Joints connect two links Joints connect two links

“Degrees of Freedom”（自由度）

Degrees of freedom (DoF) is the number of iDegrees of freedom (DoF) is the number of independent movements the robot is capablndependent movements the robot is capable of e of

Ideally, each joint has exactly one degree of Ideally, each joint has exactly one degree of freedom freedom • degrees of freedom = number of jointsdegrees of freedom = number of joints

Industrial robots typically have 6 DoF, but 3, Industrial robots typically have 6 DoF, but 3, 4, 5, and 7 are also common 4, 5, and 7 are also common

Types of Joints

Although there are a few other types, mAlthough there are a few other types, most current industrial robots use one of tost current industrial robots use one of two types of joints: wo types of joints: • Prismatic or Translational (also called LinePrismatic or Translational (also called Line

ar)ar)（平动关节）（平动关节） • Revolute or RotationalRevolute or Rotational （旋转关节）（旋转关节）

Prismatic Joints

Prismatic (Translational, Linear, Prismatic (Translational, Linear, Rectilinear) joints allow motion along a Rectilinear) joints allow motion along a straight line between two linksstraight line between two links

Link 1

Link 2

Revolute Joints

Revolute (Rotational) joints allow motion Revolute (Rotational) joints allow motion along a circular arc between two linksalong a circular arc between two links

Link 1Link 2

Relative Motion provided by Revolute Joint

Mechanical Configurations

Industrial robots are categorized by the first three joint types

Five different robot configurations: • Cartesian (or Rectangular)（直角坐标）• Cylindrical, （圆柱坐标）• Spherical (or Polar),（球坐标 ) • Jointed (or Revolute), and • SCARA

Cartesian Configuration

All three joints are All three joints are prismatic (PPP) prismatic (PPP) Commonly used for Commonly used for positioning tools, positioning tools, such as dispensers, such as dispensers, cutters, drivers, and cutters, drivers, and routersrouters

Cartesian Configuration

Often highly customizable, Often highly customizable, with options for X, Y, Z lenwith options for X, Y, Z lengths gths

Payloads and speeds vary Payloads and speeds vary based on axis length and based on axis length and support structures support structures

Simple kinematic equationSimple kinematic equationss

Robot Workspace（工作空间）

Workspace is the volume of space reachable by the end-effector（末端执行器）

Everywhere a robot reaches must be within this space

Tool orientation and size also important!

Cartesian Workspace

Easiest workspace to compute and visualizeEasiest workspace to compute and visualize Generally a simple “box” with width (X travel), Generally a simple “box” with width (X travel),

depth (Y travel), and height (Z travel) depth (Y travel), and height (Z travel)

Gantry Robot

A gantry robot is a special type of A gantry robot is a special type of Cartesian robotCartesian robot

X

Y

Z

Gantry Robot

Vary widely in size, workspaces from “bVary widely in size, workspaces from “breadloaf” size to several cubic metersreadloaf” size to several cubic meters

Characteristics of Cartesian Robots

• Advantages:Advantages: easy to visualize easy to visualize have better inherent have better inherent

accuracy than most accuracy than most other types other types

easy to program off-easy to program off-line line

highly configurable - highly configurable - get the size needed get the size needed

• Disadvantages:Disadvantages: not space efficient not space efficient external frame can be external frame can be

massive massive Z axis “post” frequently Z axis “post” frequently

in the way in the way Axes hard to seal Axes hard to seal Can only reach in front Can only reach in front

of itselfof itself

Cylindrical Configuration

First joint is revolute First joint is revolute (rotation) Next two (rotation) Next two joints are prismatic joints are prismatic (RPP) (RPP)

Cylindrical Configuration

Vertical Z axis is located Vertical Z axis is located inside the base inside the base

Compact end-of-arm Compact end-of-arm design that allows the design that allows the robot to "reach" into tight robot to "reach" into tight work envelopes without work envelopes without sacrificing speed or sacrificing speed or repeatabilityrepeatability

Cylindrical Design Robot

Cylindrical Workspace

Another “easy” workspace to compute Another “easy” workspace to compute and visualizeand visualize

Characteristics of Cylindrical Robots

• Advantages:Advantages: large workspace for large workspace for

size size easily computed easily computed

kinematics kinematics can reach all around can reach all around

itself itself reach and height reach and height

axes rigid axes rigid

• Disadvantages:Disadvantages: cannot reach above cannot reach above

itself itself horizontal axis horizontal axis

frequently in the way frequently in the way largely fallen “out of largely fallen “out of

favor” and not favor” and not common in new common in new designsdesigns

Spherical Configuration

First two joints are First two joints are revolute (rotation) revolute (rotation) Last joint is prismatic Last joint is prismatic (RRP) (RRP)

One of the earliest commoOne of the earliest common robot designs (original Un robot designs (original UniMate) niMate)

Used in a variety of industrUsed in a variety of industrial tasks such as welding ial tasks such as welding and material handlingand material handling

Spherical Configuration

Spherical Design Robots

Spherical Workspace

Workspace Workspace shaped like shaped like parts of parts of “orange peel” “orange peel”

Harder to Harder to compute and compute and visualizevisualize

Spherical Workspace

Characteristics of Spherical Robots

• Advantages:Advantages: large workspace for large workspace for

size size easily computed easily computed

kinematics kinematics

• Disadvantages:Disadvantages: has short vertical has short vertical

reach reach horizontal axis horizontal axis

frequently in the way frequently in the way also fallen “out of also fallen “out of

favor” and not favor” and not common in new common in new designsdesigns

Anthropomorphic Configuration

First three joints are First three joints are revolute or revolute or rotational (RRR)rotational (RRR)

Easily the most Easily the most common type of common type of modern robotmodern robot

Anthropomorphic Configuration

Suitable for a wide Suitable for a wide variety of industrial variety of industrial tasks, ranging from tasks, ranging from welding to assemblywelding to assembly

Often called an Often called an anthropomorphic arm anthropomorphic arm because it resembles a because it resembles a human arm human arm

Anthropomorphic Configuration

Anthropomorphic association extends to Anthropomorphic association extends to names of the links & jointsnames of the links & joints

Joint 1 - “Waist”

Joint 2 - “Shoulder”

Joint 3 - “Elbow”

Anthropomorphic association extends to Anthropomorphic association extends to names of the links & jointsnames of the links & joints

Link 1 - “Trunk”

Link 2 - “Upper Arm”

Link 3 - “Forearm”

Anthropomorphic Configuration

Very hard to compute and visualizeVery hard to compute and visualize

Anthropomorphic Configuration

Characteristics of Anthropomorphic Robots

• AdvantagesAdvantages:: excellent reach for sizeexcellent reach for size can reach above or can reach above or

below obstacles below obstacles characteristics similar characteristics similar to human arm to human arm

large workspace for large workspace for size size

• Disadvantages:Disadvantages: complicated kinematics complicated kinematics difficult to program off-lindifficult to program off-lin

ee

workspace difficult to visworkspace difficult to visualize & compute ualize & compute

small errors in first few josmall errors in first few joints are amplified at end-ints are amplified at end-effectoreffector

Kuka KR6/2

Payload: 13 lb (6 kg)Payload: 13 lb (6 kg) Max Reach: 62 in Max Reach: 62 in

(1570 mm)(1570 mm) Repeatability: Repeatability:

<± 0.004 in <± 0.004 in (<± 0.1 mm)(<± 0.1 mm)

Weight: 450 lb (205 Weight: 450 lb (205 kg)kg)

SCARA Configuration

First two links are First two links are revolute, last link is revolute, last link is prismatic (RRP)prismatic (RRP)

SCARA stands for SCARA stands for Selective Compliance Selective Compliance Assembly Robot ArmAssembly Robot Arm

SCARA Configuration

Rigid in the vertical Rigid in the vertical direction direction

Compliant in the Compliant in the horizontal direction horizontal direction

Used for assembly in Used for assembly in a vertical direction a vertical direction • circuit board circuit board

component insertion component insertion

SCARA Workspace

Workspace shaped Workspace shaped somewhat like a somewhat like a donut donut

maximum outer maximum outer radius radius

minimum inner minimum inner radius radius

uniform height uniform height

Nimbl Junior 500

Payload: 11 lb (5 kg)Payload: 11 lb (5 kg) Max Reach: 20 in (500 Max Reach: 20 in (500

mm) mm) Repeatability:Repeatability:

<± 0.001 in <± 0.001 in (<± 0.025 mm)(<± 0.025 mm)

Weight: ??? lb (?? kg)Weight: ??? lb (?? kg)

Characteristics of SCARA Robots

• Advantages:Advantages: fast cycle times fast cycle times excellent repeatability excellent repeatability

good payload capacity good payload capacity large workspace large workspace height axis is rigidheight axis is rigid

• DisadvantagesDisadvantages:: hard to program off-linehard to program off-line often limited to planar often limited to planar

surfaces surfaces typically small with relatively typically small with relatively

low load capacity low load capacity two ways to reach same two ways to reach same

pointpoint

Robot Arms & Wrists

Most robot arms have 3 “degrees of freedom” Most robot arms have 3 “degrees of freedom” • can position the end of the arm at “any” point in 3-can position the end of the arm at “any” point in 3-

D space D space

Robot “wrists” also have 3 “degrees of freedoRobot “wrists” also have 3 “degrees of freedom” m” • usually all revolute / rotational joints usually all revolute / rotational joints • used to provide the final orientation to the “gripper” used to provide the final orientation to the “gripper”

or “end-effector”or “end-effector”

Roll - Pitch - Roll Wrist

Can have problems when the first “roll” axis aligns with the last “roll” axis

Three main degrees of freedom

Wrist

Yaw - Pitch - Roll Wrist

Modeling and Control of Manipulators

ModelingModeling

• KinematicsKinematics （运动学）（运动学）• Differential kinematicsDifferential kinematics （微分运动学）（微分运动学）• Dynamics Dynamics （动力学）（动力学）

Modeling and Control of Manipulators

ControlControl

• Trajectory planning （轨迹规划）

• Motion control（运动控制）

• Hardware/software architecture

MATLAB Robot Toolbox

http://www.cat.csiro.au/cmst/staff/pic/robot

http://www.petercorke.com/Robotics

%20Toolbox.html

Class problems

Determine the D.O.F and joint types of each robot

Use the web to research the different Use the web to research the different

manufacturers and types of industrial robots manufacturers and types of industrial robots

available. available.

Download the robot toolbox for MATLABDownload the robot toolbox for MATLAB

Review linear algebra and mechanicsReview linear algebra and mechanics

Assignment