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• To understand the basic concepts associated with thedesign and functioning and applications of Robots
• To study about the drives and sensors used in Robots
• To learn about analyzing robot kinematics and robotprogramming
Unit I : Fundamentals of Robot
Unit II : Robot Drive Systems & End Effectors
Unit III : Sensors & Machine Vision
Unit IV : Robot Kinematics & Robot Programming
Unit V : Implementation & Robot Economics
Groover.M.P. “Industrial Robotics, technology, programming and application” Mc‐Graw Hill book and co.
Fu.K.S , Gonzalac R.C ,Lee C.S.G, “Robotics Control, sensing ,vision and intelligence”, Mc‐ Graw Hill book co 2011.
Yoram Koren , “Robotics”, McGraw Hill 2006
Janakiraman P.A. “Robotics and Image Processing”, Tata McGraw Hill, 2002
“Robotic Engineering: An Integrated Approach”, Richard D. Klafter
Fixed Automation ‐ Automotive
Programmable Automation (Robot)
Flexible Automation (FMS)
1922 Czech author Karel Capek wrote a story called Rossum’s Universal Robots and introduced the word “Rabota”(meaning worker)
1954 George Devol ‐ first programmable Robot.
1962 Unimation was formed, first industrial Robots appeared.
1973 Cincinnati Milacron ‐ T3 model robot, which became very popular in industry.
As defined by Robotics Industry Association (RIA)
A re‐programmable, multifunctional manipulator designed to move material, parts, tools or specialized devices through variable programmed motion for a variety of tasks
As defined by ISO 8373An automatically controlled, reprogrammable,multipurpose manipulator programmable inthree or more axes, which may be either fixed inplace or mobile for use in industrial automationapplications.
A robot may not injure a human being, or , through inaction, allow a human to be harmed
A robot must obey orders given by humans except when that conflicts with the First Law.
A robot must protect its own existence unless that conflicts with the First or Second Laws
According to Robotics Institute of America (RIA)
Variable‐Sequence Robot : A device that performs the successive stages of a task according to a predetermined method easy to modify
Playback Robot : A human operator performs the task manually by leading the Robot
Numerical Control Robot : The operator supplies the movement program rather than teaching it the task manually.
Intelligent Robot : A robot with the means to understand its environment and the ability to successfully complete a task despite changes to the environment.
Manipulator : Main body of the Robot & consists of links, joints and structural elements.
End Effector : part that generally handles objects, makes connection to other machines, or performs the required tasks.
Physical construction of Body, Arm & Wrist
Base – Fixed to the floor or mobile base
Body – Attached to the base
Arm ‐ Attached to the body
Wrist ‐ At the end of the arm
Actuators : muscles of the manipulators : servomotors, stepper motors, pneumatic, hydraulic cylinders etc.
Sensors : collect information about the internal state of the robot or to communicate with the outside environment : vision system, touch and tactile sensors etc
Controller : controls the motions of the actuator and coordinates these motions with the sensory feedback information.
End Effector : Hand (not part of anatomy)
Based on,Type of system
Point – to – Point robot systemContinuous – path robot system
Type of control loopsOpen loop control systemClosed loop control system
Type of coordinate system
Each axis moves from one point to next as fast as it can i.e. path is not controlledRobot is stationary during executionTime for the longest axial motion is calculated (t)Velocities of other axes is based on ‘t’‘t’ is same for all axesMotion in all axes terminated simultaneouslyThe trajectory is arbitraryEg. spot welding
All axes move simultaneously, each at different velocityVelocities are coordinated under computer controlTime of motion ‘t’ is different for each axisEg. spray painting, arc welding
Control is given to the individual axisNo feed back is obtainedUsed for loading / unloading applications
Control is given to the individual axisFeed back is obtained through sensorsCorrective signals are sent by control unit
Cartesian Coordinate Robot 3 Linear axes (LLL) – prismatic or slidingRectangular work volumeManipulator H/W & control program similar to CNC
AdvantagesSimple algorithmsEqual & constant spatial resolution
DisadvantagesLacks mechanical flexibilityCannot reach objects on the floorSpeed of operation in horizontal plane isslower than with robots of rotary base
Cylindrical Coordinate (R2P): 2 prismatic joints and one revolute joint.
Results in a larger work envelope than a rectangular robot
Suited for pick‐and‐place operations
Vertical structure conserves floor space.Deep horizontal reach is useful for far‐reaching operations.
Capacity is capable of carrying large payloads
Overall mechanical rigidity is lower than that of the rectilinear robots because their rotary axis must overcome inertia.
Repeatability and accuracy are also lower in the direction of rotary motion.
Configuration requires a more sophisticated control system than the rectangular robots.
Cylindrical Coordinate (R2P): 2 prismatic joints and one revolute joint.
Spherical joint (2RP): 2 rotary & 1 prismatic joint
Provides a larger work envelope than the rectilinear or cylindrical robot.
Design gives weight lifting capabilities.
Advantages and disadvantages same as cylindrical‐coordinated robot.
Spherical joint (2RP): 2 rotary & 1 prismatic joint
Articulated/Jointed Arm (3R) : all revolute, similar to a human’s arm.
AdvantagesFlexible & VersatileCan easily go up & downCan reach its base & Floor
DisadvantagesSpatial resolution depends entirely on the arm position
Selective Compliance Assembly Robot Arm (SCARA) (2R1P): two revolute joints that are parallel to move in a horizontal plane, prismatic joint that moves vertically
POM is the measure of performancePrecision – function of three factors:
Spatial ResolutionAccuracyRepeatability
Definition applies:At robot’s wrist end with no hand attachedTo the worst case condition – arm fully extendedContext of point‐to‐point robot
SR – smallest increment of movement into which the robot can divide its work volume
SR depends on:System’s control resolution (CR)Robot’s mechanical inaccuracies
CR – controller’s ability to divide the total range of movement for a particular joint into individual increments (addressable points) that can be addressed in the controllerNumber of increments =
n = number of bits in the controller memoryEg. 8 bit storage
No. of increments = = 256 discrete points
Control resolution =
1 DOF robot – sliding joint – range 1 m. 12 bit storageNo. of increments = = 4096Total range is divided into 4096 increments.
Each position separated by =
= 0.000244m Control resolution = 0.244mm
Steel Rule of length 300 mm
No. of divisions = 30Resolution =
No of divisions = 300Resolution =
No of divisions = 600Resolution =
Elastic deflection in structural members
Gear backlash
Stretching of pulley cards
Leakage of hydraulic fluids
Ability to position its wrist end at a desired target point within the work volume
Ignoring mechanical inaccuracies;
Accuracy =
Accuracy varies within work volume; worse when the arm is fully extended
Heavier work loads results in lower accuracy
Ability to position its wrist or an end effector attached to the wrist at a point in space that had previously been taught to the robot.
In 3D space, it is small sphere surrounding the programmed point ‘p’
Size of the sphere is larger when the arm/EE is farther away from the center of the robot
TravelX – ‐ 150 mmY – ‐ 225 mmZ – ‐ 180 mm
VelocityX ‐ 600mm/secY ‐ 700mm/secZ ‐ 140mm/sec
ResolutionX ‐ 2.5µmY ‐ 2.5µmZ ‐ 0.5µm
RepeatabilityX ‐ 16µmY ‐ 15µmZ ‐ 10µm
Payload ‐ 6Kgs
ReachHorizontal ‐ 549mmVertical ‐ 501mmWaist Rotation ‐ 270˚
SpeedHorizontal ‐ 500mm/secVertical ‐ 500mm/secWaist ‐ 180˚/sec
Payload ‐ 2kg
Repeatability ‐
Resolution ‐ 0.075mm
Horizontal Reach – 700mm
Motion RangeJoint 1 ‐Joint 2 ‐Joint 3 ‐ +206˚ ‐ 110˚
Motion SpeedJoint 1 ‐ 180˚/secJoint 2 ‐ 400˚/secJoint 3 ‐ 280˚/sec
Repeatability ‐
Payload – 6 Kg
To move its body, arm and wrist through a series of motions and positions.Individual joint motions are referred as Degrees of Freedom (DOF)4 – 6 DOFOpening & closing of gripper is not DOF
Motions accomplished by means of powered joints3 Joints – Arm & Body2 – 3 Joints ‐ wristLink – rigid members connecting jointsLinks connected to form – Serial / Parallel chainIndustrial manipulators – serial chain
Relative motion of the adjoining links , either linear or rotational
Sliding or translational motion of connecting links:Piston – cylinder mechanism Telescoping mechanismRack and pinion
Rotational ‘R’ : axis of rotation is perpendicular to the axes of the two connecting links
Twisting ‘T’ : Axis of rotation is parallel to the axes of links
Revolving ‘V’ : I/P link is parallel to axis of rotation; o/p link perpendicular to the axis of motion.
To orient the end effector
Roll : Rotation of wrist mechanism about arm axisPitch: with Roll in center position, up and down rotation of the wristYaw: with Roll in center position, right or lift rotation of the wrist
Die casting
Dip coating
Forging
Glass handling
Heat treating
Injection molding
Machine tool handling
Material transfer
Press loading
Stacking
AutomationRobotics - HistoryRobot DefinitionThree laws by AsimovTypes of RobotRobot – Main PartsRobot AnatomyRobot ‐ AccessoriesClassification of RobotsPoint‐to‐Point (PTP) systemContinuous path systemOpen loop control system
Closed loop control systemRobot ConfigurationsCartesian RobotCylindrical Robot Spherical RobotJointed Arm RobotSpatial ResolutionAccuracyRepeatabilitySpecifications of Cartesian RobotSpecifications of Cylindrical RobotSpecifications of Articulated Robot
• has at least two "legs" (or "arms"). Most of its joints are not actuated, and many of these passive joints have several degrees-of- freedom (DOFs)
• Telescoping-leg hexapod used in most motion simulators (often called "motion platforms")
• Delta robot, generally used for rapid pick-and-place.
