ROBOTICS AND MACHINEROBOTICS AND MACHINE VISION SYSTEM VISION SYSTEM

OBJECTIVEOBJECTIVETo study the basic components of an

industrial robot and its specificationsTo derive the kinematics, dynamics and

velocities equation for different robot configurations

To manipulate the trajectory of robots and program the robot for specific applications

To learn the machine vision systems through image acquisition, processing and analysis

COURSE OUTCOMESCOURSE OUTCOMESAt the end of this course, student will be able to: Comprehend the basic components and total

functionality of an industrial robot Solve the kinematics, dynamics and velocity

equations for different configurations of the manipulators

Recognize different modes of trajectory planning and robot programming for industrial applications

Understand the role of machine vision system and image processing techniques

HISTORHISTORYY

INTRODUCTIONINTRODUCTIONThe term robot has its

origin in a Czech word “robota” meaning “forced labour”. It was first introduced by the playwright Karel Capek, in a 1920 play R.U.R(Rossum’s Universal robot.

Continued….Continued….

ROBOT INSTITUTE OF AMERICA (RIA): A robot is a reprogrammable multifunctional manipulator designed to move material, parts, tools, or specialized devices through variable programmed motions for the performance of a variety of tasksTele operators + numerically controlled milling machines = Robot

Milestones in the History of Milestones in the History of RoboticsRobotics 1947 — the first servo electric powered tele operator is

developed 1948 — a tele operator is developed incorporating force

feedback 1949 — research on numerically controlled milling machine

is initiated 1954 — George Devol designs the first programmable robot 1956 — Joseph Engelberger, a Columbia University physics

student, buys the rights to Devol’s robot and founds the Unimation Company 1961 — the first Unimate robot is installed in a Trenton,

New Jersey plant of General Motors to tend a die casting machine 1961 — the first robot incorporating force feedback is

developed

Sample of Teleoperation device

Tele operation Tele operation architecturearchitecture

Continued….Continued…. 1963 — the first robot vision system is developed 1971 — the Stanford Arm is developed at Stanford

University 1973 — the first robot programming language (WAVE) is

developed at Stanford 1974 — Cincinnati Milacron introduced the T3 robot with

computer control 1975 — Unimation Inc. registers its first financial profit 1976 — the Remote Center Compliance (RCC) device for

part insertion in assembly is developed at Draper Labs in Boston

1976 — Robot arms are used on the Viking I and II space probes and land on Mars

1978 — Unimation introduces the PUMA robot, based on designs from a General Motors study

Continued….Continued…. 1979 — the SCARA robot design is introduced in Japan 1981 — the first direct-drive robot is developed at Carnegie-

Mellon University 1982 — Fanuc of Japan and General Motors form GM Fanuc to

market robots in North America 1983 — Adept Technology is founded and successfully markets

the direct drive robot 1986 — the underwater robot, Jason, of the Woods Hole

Oceanographic Institute, explores the wreck of the Titanic, found a year earlier by Dr. Robert Barnard.

1988 — Staubli Group purchases Unimation from Westinghouse 1988 — the IEEE Robotics and Automation Society is formed 1993 — the experimental robot, ROTEX, of the German

Aerospace Agency was flown aboard the space shuttle Columbia and performed a variety of tasks under both teleoperated and sensor-based offline programming modes

Continued….Continued…. 1996 — Honda unveils its Humanoid robot; a project begun in

secret in 1986 1997 — the first robot soccer competition, RoboCup-97, is held in

Nagoya, Japan and draws 40 teams from around the world 1997 — the Sojourner mobile robot travels to Mars aboard NASA’s

Mars Path Finder mission 2001 — Sony begins to mass produce the first household robot, a

robot dog named Aibo 2001 — the Space Station Remote Manipulation System (SSRMS) is

launched in space on board the space shuttle Endeavor to facilitate continued construction of the space station

2001 — the first telesurgery is performed when surgeons in New York performed a laparoscopic gall bladder removal on a woman in Strasbourg, France

2001 — robots are used to search for victims at the World Trade Center site after the September 11th tragedy

2002 — Honda’s Humanoid Robot ASIMO rings the opening bell at the New York Stock Exchange on February 15th

Basic components of robot

Manipulator

Control unitShoulder

Elbow Arm

Wrist

1

2 3

4

5

6

6 Revolute joints= 6R robot

Motion power unit

A robot is a group of several subsystems each with its own function:Mechanical system By which the robot interacts with the surrounding environment. It usually performs one particular task. It consists of actuators, joints, wrists, tools, etc. . .Electrical system Consisting of sensors, electrical/pneumatic/hydraulic actuators, computers, etc. . Control system This system receives high level orders and translates them into commands for actuators.Sensor system It measures different physical magnitudes so that control system is able to perform the correct action.

Continued….Continued….

Robot Laws

1. A robot may not injure a human beings, or, through inaction, allow one to come to harm.

2. A robot must obey the orders given to it by human beings except where such orders would conflict with the first law.

3. A robot must protect its own existence as long as such protection does not conflict with the First or Second Laws

ROBOT LIKE DEVICESROBOT LIKE DEVICES- near relationsProstheses: make use of either

hydraulic or servo motor actuators, utilize servo control and have mechanical linkages.

To produce an action in such device originates in brain of the human being. ExoskeletoExoskeletonsnsCollection of mechanical linkages

that are made to surround either human limbs or the entire human frameAbility to amplify a humans power

Telecherics:Either hydraulic or servo motor actuatorsClosed loop by human operatorEspecially useful in dealing with hazardous substance such as radioactive waste

Locomotive mechanisms:That imitate human beings or animals by having the ability to walk on two or four legs.Human operator is required to execute the locomotive process

Why Use Robots?Why Use Robots?Why Use Robots?Why Use Robots?• Consistent performanceConsistent performance in repetitive boring tasks, such as in repetitive boring tasks, such as

machine loading and inspectionmachine loading and inspection• HazardousHazardous or uncomfortable or uncomfortable environmentsenvironments, such as those , such as those

associated with spray painting, arc welding, grinding, associated with spray painting, arc welding, grinding, deep sea diving, radioactive materials handlingdeep sea diving, radioactive materials handling

Cost reduction and increased productivity– robots can work up to 10 times faster than people in repetitive low-

skill tasks, such as spot welding, drilling and reviting– in general, robots work at about the same rate as a person, but cost

about 50% as much as a person per hour– robots can work 24 hrs/day, do not take breaks or sick leave

The benefits(advantages) of application of robots in The benefits(advantages) of application of robots in manufacturing industries can be listed as follows :manufacturing industries can be listed as follows :

1) Flexibility – essential for automation of batch production.2)Reduced change over time and cost – needed for mixed products on high volume lines.3) Better quality.4) Consistency in production rate and quality.5) Increased productivity rate and quality.6)  Reduced lead time and capital cost.7)  Increased morale of the workers.8)Reduction in overall manufacturing

cost/price or unit.

The major conditions justifiable for robot application in the industries essentially are :

a) Dull for repetition, monotony and fatigue.b) Difficult for arduousness and complexity of work and

desired precision and consistency.

c)  Dirty – nonworkable for human being.d) Dangerous – hazardous for chemicals, gas, heat,

noise, electricity, radio-activity etc. unsafe-underwater, space, mines.

a) Industry – I) Material handling applications ii) Processing operations iii) Assembly operations iv) Inspection operation i)Material Handling application.

Equipped with right type of gripper or end effectors for various applications like Part placement

Pick up part from one location and place at new location.

Basic application –pick and place. Ex. Transferring parts from one conveyor to another.

ii) Palletizing & depalletising Palletizing : stacking parts on one on top of

the other. Ex. Taking parts from an assembly line and

stacking them on a palette. Depalletising: opposite of Palletizing Ex. Taking parts from a palette and placing

them on an assembly line.

• The simple task of moving The simple task of moving a part or object from one a part or object from one location to another within location to another within the work area in one of the work area in one of the most common the most common applications for robots applications for robots today. (palletization & today. (palletization & depalletization).depalletization).

• Other important parts-Other important parts-handling applications handling applications involve the acquiring of involve the acquiring of blank or unfinished parts blank or unfinished parts and feeding them into and feeding them into some type of machine tool some type of machine tool for finishing.for finishing.

iii) Material handlingiii) Material handling

iv) Machine loading and unloading

Machine loading :press working operation. Machine unloading :bin picking,die casting,

plastic molding. Machine loading and unloading:machining

operation,heat treatment,forging. Insertion operations:

v) Processing operations Robot performs a processing operation on the

part. EX. Spot welding Continuous arc welding Spray painting Metal cutting and deburring operations Drilling,grinding,laser and water jet cutting.

Riveting. Adhesive and sealant dispensing.

The most popular applications of robots are in industrial welding.

The repeatability, uniformity quality, and speed of robotic welding are unmatched.

The two basic types of welding tasks performed by robots are spot welding and arc welding, although laser welding is done.

Another major welding task performed by robots is seam welding

Welding

Another popular and efficient use for robots is in the field of spray painting.

The consistency and repeatability of a robot’s motion have enabled neat perfect quality while at the same time wasting no paint

The spray painting done relieve humans from a hazardous, though skillful job, while at the same time increasing work quality, uniformity, and cutting costs.

Painting robots have 2 special features the capability of moving the painting head over a complex surface at a constant velocity relative to that surface, and a non spark emitting safety feature.

Painting

E.g. Assembly of printed circuit boards. Extremely accurate placement before insertion of transistors & chips is usually required.

Robots can also be used to assemble several parts of an automobile.

Assembly operations Assembly operations represents an attractive

application of robots because these jobs may be extremely tedious because of their repetitive nature.

Geometrical configuration.

• Arm moves in 3 linear axes. x,y,z axes

Cartesian3P

1.Cartesian robot

Cartesian3PCartesian Robot:

1.Cartesian robot

1.Cartesian/rectangular

Three Linear axis of motion.(3P)Left-rightForward –backwardUp-down(z)Work envelopeIs rectangular.

Advantages

1. Linear movements allow for simple controls2. High degree of mechanical rigidity ,accuracy

and repeatability 3. They can carry heavy loads because the

weight –lifting capacity does not vary at different locations in work envelope.(Independent of gravity loading)

4. Resolution-smallest possible increment same for all axis.

Disadvantages

1. Large structural framework.2. More complex mechanical design for linear

sliding motions.3.Movement is limited to one direction at a time.4.Can only reach in front of itself

Applications

1. Pick and place operation2. Adhesive applications(mostly long and straight)3. Assembly and sub assembly(mostly straight)4. Inspection5. Nuclear material handling6. General machining and loading operation.7. Water jet cutting.

Arm rotates about the base, moves in and out, and up and down

2.Cylindrical coordinates robot

Cylindrical coordinate

A cylindrical or post type co-ordinate robot has two linear motion and one rotary motion.

Radial motion ® The first co ordinate describes the angle of base rotation. Up-down(Z) Work volume is cylindrical. Reach and height axis rigid Base resolution in degrees

Cylindrical coordinate

• Advantages1.Two linear axes make the mechanical design less

complex than the Cartesian robots.2.vertical structure conserves space3.Can reach all-round itself

• Disadvantages1.Cannot reach above itself.2.Horizontal motion is circular.3.Won,t reach around obstacles.4.Base rotation axis is less rigid. 5.Repeatability and accuracy are lower due to rotary joint.

3. Polar/Spherical RobotArm rotates about the base, moves in and out, and up and

down

Spherical or polar robots

Spherical or polar robots

A spherical co-ordinate robot has one linear motion and two rotary motion.

I.e(2R-1P) The first co ordinate describes the angle of

base rotation. The second co ordinate describes the angle

Ø of elbow. Radial motion ®

Advantages1. Design is simple and gives good weight lifting

capabilities.2. Long horizontal reach.3. Configuration suited for applications where small

amount of vertical movement is adequate.

Disadvantages.1. Short vertical reach2. Less stability3. Can’t reach around obstacles.4. Repeatability and accuracy are lower due to rotary

joints.

Application

1. Press loading2. Dip coating3. Stacking and unstacking 4. Part cleaning5. Heat treatment 6. Forging.

4.Joined-arm or revolute-coordinates robot 3 axes rotational

Also called articulated robot

Most anthromorphic or human like robot.

i.e design is similar to human arm.

Rotation about base-waist(vertical axis)

Shoulder(horizontal) Elbow. (horizontal) Work envelope is circular

when viewed from top.

From side ,the envelope has circular outer surface and scalloped inner surface.

Advantages1. Can reach around obstacles.2. Large work area for least floor space.Disadvantages1. Less accuracy due to rotary joints.2. Sophisticated controller because programming

is complex.3. Less stable especially at maximum reach.

BASIC COMPONENTS OF ROBOT

Manipulator

Control unitShoulder

Elbow Arm

Wrist

1

2 3

4

5

6

6 Revolute joints= 6R robot

Motion power unit

1. Manipulator

The manipulator is a mechanical unit that provides motion similar to human arm.

The manipulator consists of a series of rigid members ,called links and are connected at joints

Its primary function is to provide the specific motion that will enable the tooling at the end to do the required work

The motion of joints are accomplished by actuator The manipulator bends, slides ,or rotates about

these joints which as referred to as degrees of freedom.

The manipulator itself may be thought of as being composed of three divisions

1. The major linkages.(Positioning)2. The minor linkages(wrist components-orientation)3. The end effector.

The Minor Linkages(wrist Assembly-orientation)

The wrist movement is designed to orient the end effector properly.

Normally wrist is provided with 3 DOF.

A typical wrist is shown The DOF are 1. Wrist roll 2. Wrist pitch3. Wrist Yaw.

1. Wrist roll:-This involves rotation of mechanism about the arm axis. Also called as wrist swivel.

2. Wrist pitch:-Given the wrist roll is in its center position ,the pitch would involve the up or down rotation of the wrist. It is sometimes called wrist bend.

3. Wrist yaw :-Given the wrist roll is in its center position ,the pitch would involve the right or left rotation of the wrist.

  End-effector's: Grippers and tools The device which is attached to the wrist of a robot to

enable it work by basically gripping and releasing parts or tools is called end-effector or simply robot hand.

These, special purpose fixture like attachments are custom engineered and procured separately by :

1) placing special order to the robot manufacturer/supplier if they have such provision.

2)  design, and build in the users’ side3) buy standard device from market and adopt it to

requirement4)   get it by contract or consultancy.  

End Effector (Gripper):

Standard handFinger actionForce multiplication

Self-aligning fingersSecure gripNo object ‘cocking’

Round object fingerGrips different sizesor different shapes

Cam-operated handLifts heavy objectsNarrow size range

Arc welding

torch

Pouringladle

Spotwelding

gun