Automation and Robotics Week 08 Theory Notes 20ME51I.pdf

Vidya Vikas Educational Trust (R),
Vidya Vikas Polytechnic
27-128, Mysore - Bannur Road Alanahally, Alanahally Post, Mysuru, Karnataka 570028
Prepared by: Mr Thanmay J.S, H.O.D Mechanical Engineering VVETP, Mysore
WEEK08
Day 01 Session
Concepts of Industrial Robots
An industrial robot is an autonomous system of sensors, controllers, and actuators on an articulated
frame that executes specific functions and operations in a manufacturing or processing line. They operate
continuously through repetitive movement cycles as instructed by a set of commands called a program. These
machines minimize or eliminate the human factor to gain various advantages in processing speed, capacity,
and quality.
The main structure of an industrial robot is the arm. The arm is a structure made of links and joints.
Links are rigid components that move through space in the range of the robot. The joints, on the other hand,
are mechanical parts that connect two links while allowing translational (prismatic) or rotational (revolute)
movement. The configuration of these two components classifies the different types of industrial robots.
The most important part of the robot is the end-of-arm-tool (EOAT), or end effector. The EOAT is the
component that manipulates the product or process by moving or orienting. They perform special operations
such as welding, measuring, marking, drilling, cutting, painting, cleaning, and so on.
An industrial robot integrator supplies robotic systems that are made by an original equipment
manufacturer (OEM). A robot integrator, or “system” integrator, can provide a complete “turn-key” robotic
work cell with parts feeders, end effectors, and guarding to form a complete work cell. Robotic integrators
have a wider array of solutions since they can offer more products and represent more than one company for
each robot category.
Advantages of Industrial Robots
• Faster Rate of Production
• Higher Load Capacity
• Improved Safety
• Lower Operating Cost
• Better Repeatability and Precision
• High Accuracy
• Excellent Product Quality
• More Compact Production Area

Applications of Robotics
a) Product Assembly: Industrial robots are widely used as assembly machines. They are suitable for highly
repetitive but precise tasks that are tedious for a human operator. Their end effectors are usually mechanical
grippers that pick, place, and orient small or large parts in quick succession. Sensors are optional and are
typically used for recalibrating the accuracy of the robot ‘s movements.
b) Non-Conventional Machining: Common non-conventional methods of machining include waterjet
cutting, laser cutting, abrasive jet machining, electric discharge machining (EDM), and plasma cutting. These
non-contact machining processes perform material removal by using highly concentrated streams of water,
light, electric charge, or another physical entity.
c) Palletizing and Depalletizing: Palletizing is the process of combining several individual products into a
single load for more efficient product handling, storage, and distribution. On the other hand, depalletizing is
the opposite: It is the disassembly of a palletized load. Both of these processes are labor-intensive and can
quickly become process bottlenecks. Robotic palletizers are used for their better product handling and cost-
efficiency. End effectors integrated into robotic palletizers are mechanical, pneumatic, and vacuum grippers
that operate by picking, orienting, and stacking items, similar to the operation of assembly machines.
d) Welding: Robotic welding systems are commonly seen in automotive manufacturing plants, but they are
also widely used in many high-volume metal fabrication processes. Increased market competitiveness
created the need for better product quality and higher operating rates. This, in turn, requires more accurate
and precise welding processes. The main advantage of using industrial robots in welding is better control of
different parameters such as current, voltage, arc length, filler feed rate, weld rate, and arc travel speed.
e) Painting and Coating: Painting and coating is a sensitive operation that requires highly accurate and
repeatable movements to create a layer with uniform thickness. On top of the required accuracy and
precision, painting involves working with potentially hazardous chemicals. Many pigments and solvents are
poisonous, and some can even create an explosive atmosphere. All these hazards are mitigated by using
industrial robots.
f) Grinding, Polishing, and Buffing: Grinding, polishing, and buffing are common secondary fabrication
processes used to improve the product's final appearance and surface properties. These processes involve
repetitive, oscillating motions of the abrasive or polishing material. A robotic arm can easily mimic this
simple movement of the tool.
g) Deburring: Another capability of modern industrial robots is deburring. This is a process where the robot
holds a rotating tool, usually a sanding drum, wire wheel, or carbide deburr tool, and follows a pre-
programmed path to deburr and smooth parts from casting or injection molding..
h) Machine Loading and Unloading: Machine loading and unloading take advantage of robotic systems'
high load capacity and mechanical advantage. Specific machine loading and unloading applications include
transferring large metal or plastic parts from casting, moulding, and forging processes to conveyor systems,
secondary processing stations, or loading machining centres with blanks for machining.
i) Inspection: Robotic inspection systems can use measuring devices such as optical sensors, proximity
sensors, force transducers, ultrasonic probes, and even complete machine vision systems to perform
inspection tasks on parts or assemblies. These machines are typically used to precisely measure the
dimensions of a product to maintain quality and consistency.
j) Sorting: Sorting processes utilize the simple pick and place capability and high-speed monitoring of
robotic systems. Visual sensors detect variations in size, colour, or shape. Upon detection of an odd item, a
robot is used to pick and reject the item. Common industries using robotic sorting systems are
pharmaceuticals and electronics.

Types of Industrial robots
Industrial robots are classified according to their arm configuration. A robotic arm is composed of links and
joints. Varying the number and type of these two components yields robots with different configurations.
Below are the six types of industrial robots.
1) Cartesian Robot: A Cartesian robot is composed of three prismatic joints.
Thus, the tool is limited to linear motion at each axis but can still generate
circular moves through kinematic models that allow circular interpolation.
The name Cartesian is derived from the three-dimensional Cartesian
coordinate system, which consists of X, Y, and Z axes. Cartesian robots are
the simplest robotic system since their operation may only involve
translational movements. They are suitable for applications that only
require movement at right angles without the need for angular translations. Since one or two of a cartesian
robot’s prismatic joints can be supported at both ends, they can be built to handle heavier loads than other
robot types.
2) Polar Robot: Polar robots, also known as spherical robots, use the three-
dimensional polar coordinate system r, θ, and φ coordinate. Instead of having
a work envelope in the shape of a rectangular prism, polar robots have a
spherical range. Their range of motion has a radius equal to the length of the
link connecting the EOAT and the nearest revolute joint. This configuration
allows polar robots to have the farthest reach for a given arm length compared
to other robot types. The range of a polar robot can be further extended using a second link connected by a
prismatic joint. Because of their wide reach, polar robots are commonly used in machine loading applications.
3) Cylindrical Robot: As the name suggests, a cylindrical robot has a
cylindrical range of motion. This type consists of one revolute joint and two
prismatic joints. The revolute joint is located at the arm's base, allowing the
rotation of the links about the robot's axis. The two prismatic joints are used
for adjusting the radius and height of the robot’s cylindrical work envelope.
In compact designs, the prismatic joint used for adjusting the arm’s radius is
eliminated. This one revolute, one prismatic joint configuration is useful in
simple pick and place operations where the product feed is located only in one place.
4) Selective Compliant Articulated Robot Arm (SCARA): A SCARA is a
type of robot with an arm that is compliant or flexible in the horizontal or
XY-plane but rigid in the vertical direction or Z-axis. Its translational
movement on a single plane describes its “Selective Compliant”
characteristic. A SCARA has two links, two revolute joints, and a single
prismatic joint. The links and the base are connected by the revolute joints
oriented at the same axis. The prismatic joint is only for raising or lowering
the End effectors. The resulting work envelope of a SCARA is a torus. Its application is similar to that of a
cylindrical robot.

5) Delta Robot: A delta robot consists of at least three links connected to
an End effector and a common base. The End effector is connected to the
links by three undriven universal joints. On the other hand, the base is
connected by either three prismatic or revolute-driven joints. The driven
joints work together to allow the End effector to have four degrees of
freedom. For designs using prismatic joints, a fourth link or shaft is
usually connected to the End effector to enable rotation. The End effector
of a delta robot can move along all Cartesian axes and rotate around the
vertical axis, resulting in a dome-shaped work envelope. The simultaneous action of the three driven joints
makes delta robots suitable for high-speed pick and place applications.
6) Articulated Robot or Anthropomorphic Robot: Articulated robots are
the most common robots used in manufacturing processes. They perform
more complex operations such as welding, product assembly, and
machining. End effectors are mounted on articulated robots are designed to
have a full six degrees of freedom. The robot arm consists of at least three
revolute joints. A fourth revolute joint can be added to the wrist of the arm
for rotating the End effector. Its work envelope is also spherical, similar to
that of the polar robot type.
Configurations of robots
There are six major types of robot configurations: Cartesian, Cylindrical, Spherical, Selective Compliance
Articulated Robot Arm (SCARA). Articulate, and Delta (Parallel).
Robot Configuration Explanation Common Uses
Cartesian
Has the robot’s tool moving in a linear motion along
each of the Cartesian coordinates (x, y, z).
3D printers
Cylindrical
Allows its tool to rotate around a central axis. The tool
can also move towards and away from the central
axis, plus up and down the central axis.
Assembly operations, handling
of machine tools and die-cast
machines, and spot welding.
Spherical
The tool motion created by this configuration sweeps
out a workspace shaped like a sphere. It has its tool
rotate around a central axis, and the tool can also
rotate around a second axis which is placed at a 90⁰
angle on the central axis.
Die casting, injection
moulding, welding, and
material handling.
Selective Compliance
Articulated Robot
Arm (SCARA)
Uses pivot points to allow its tool to move in a
combination of the Cartesian and the cylindrical
motions.
assembly and palletizing, bio-
medical applications.
Articulated
This type of robot is the most commonly pictured
when referring to an industrial robot. As a minimum,
it needs to have at least a shoulder joint, an elbow
joint, and a wrist joint.
Assembly, arc welding,
material handling, machine
tending, and packaging.
Delta (Parallel)
Can move the robot’s tool the fastest of all of the
robot configuration types. It uses parallel linkages to
allow its tool to quickly sweep out its workspace.
A Delta can nimbly and
quickly pick and place items in
a sorting task

WEEK 8
Day 02 Session
Technical specification in Robotics
i. Accuracy: The robot's program instructs the robot to move to a specified point, it does not actually
perform as per specified. The accuracy measures such variance. That is, the distance between the
specified position that a robot is trying to achieve (programming point), and the actual X, Y and Z
resultant position of the robot end effector.
ii. Repeatability: The ability of a robot returns repeatedly to a given position. It is the ability of a robotic
system or mechanism to repeat the same motion or achieve the same position. Repeatability is is a
measure of the error or variability when repeatedly reaching for a single position. Repeatability is often
smaller than accuracy.
iii. Degree of Freedom (DOF): Each joint or axis on the robot introduces a degree of freedom. Each DOF
can be a slider, rotary, or other type of actuator. The number of DOF that a manipulator possesses thus
is the number of independent ways in which a robot arm can move. Industrial robots typically have 5
or 6 degrees of freedom.
Three of the degrees of freedom allow positioning in 3D space (X, Y, Z), while the other 2 or 3 are
used for orientation of the end effector (yaw, pitch and roll). 6 degrees of freedom are enough to allow
the robot to reach all positions and orientations in 3D space. 5 DOF requires a restriction to 2D space,
or else it limits orientations. 5 DOF robots are commonly used for handling tools such as arc welders.
iv. Resolution: The smallest increment of motion can be detected or controlled by the robotic control
system. It is a function of encoder pulses per revolution and drive (e.g. reduction gear) ratio. And it is
dependent on the distance between the tool center point and the joint axis.
v. Envelope: A three-dimensional shape, that defines the boundaries that the robot manipulator can
reach; also known as reach envelope.
vi. Reach: The maximum horizontal distance between the center of the robot base to the end of its wrist.
vii. Maximum Speed: A robot simultaneously moving with all joints in complimentary directions at full
speed with full extension. The maximum speed is the theoretical values which does not consider under
loading condition.
viii. Payload: The maximum payload is the amount of weight carried by the robot manipulator at reduced
speed while maintaining rated precision. Nominal payload is measured at maximum speed while
maintaining rated precision. These ratings are highly dependent on the size and shape of the payload
due to variation in inertia.
Wrist configuration
Roll- This is also called wrist swivel; this involves rotation of the wrist mechanism about the arm axis.
Pitch- It involves up & down rotation of the wrist. This is also called as wrist bend.
Yaw- It involves right or left rotation of the wrist.

Robot Work Volume
The work volume is determined by the following physical characteristics of the robot:
• The robot’s physical configuration (type of joints, structure of links)
• The sizes of the body, arm, and wrist components
• The limits of the robot’s joint movements
Robot Degree of Freedom
Degree of freedom basically refers to the number of ways in which an object can move. Now, simply put,
there are 2 fundamental means of movement:
1. Translation
2. Rotation
Translation can be further broken down into 3 kinds of
movements:
• Forward - Backward
• Left - Right
• Up - Down
Rotation can also be further broken down into 3 kinds of
movements:
• Pitch
• Yaw
• Roll
Total there are 6 degrees of freedom.
Joint Notation & Type of joints in robot
The Robot Joints is the important element in a robot which helps the links to travel in different kind of
movements. There are five major types of joints such as:
1) Translational motion:
▪ Linear joint (type L)
▪ Orthogonal joint (type O)
2). Rotary motion:
▪ Rotational joint (type R)
▪ Twisting joint (type T)
▪ Revolving joint (type V)
Linear Joint: Linear joint can be indicated by the letter L –Joint. This
type of joints can perform both translational and sliding movements.
These motions will be attained by several ways such as telescoping
mechanism and piston. The two links should be in parallel axes for
achieving the linear movement.

Orthogonal Joint: The O –joint is a symbol that is denoted for the
orthogonal joint. This joint is somewhat similar to the linear joint. The only
difference is that the output and input links will be moving at the right angles.
Rotational Joint: Rotational joint can also be represented as R –Joint. This
type will allow the joints to move in a rotary motion along the axis, which is
vertical to the arm axes.
Twisting Joint: Twisting joint will be referred as V –Joint. This joint
make twisting motion among the output and input link. During this process, the
output link axis will be vertical to the rotational axis. The output link rotates in
relation to the input link.
Revolving Joint: Revolving joint is generally known as V –Joint. Here, the
output link axis is perpendicular to the rotational axis, and the input link is
parallel to the rotational axes. As like twisting joint, the output link spins about
the input link.
Joint Notation Scheme
Uses the joint symbols (L, O, R, T, V) to designate joint types used to construct robot manipulator.
Separates body-and-arm assembly from wrist assembly using a colon (:)
Example: TLR: TR
Robot End Effectors
End effector are usually attached to the robot's wrist. The end effector enables the robot to accomplish a
specific task. Because of the wide variety of tasks performed by industrial robots, the end effector must usually
be custom-engineered and fabricated for each different application.
There are two categories of end effectors are grippers and tools.
1) Grippers: Grippers are end effectors used to grasp and manipulate objects during the work cycle. The
objects are usually Work parts that are moved from one location to another in the cell. Machine loading
and unloading applications fall into this category. Grippers must usually be custom designed to the variety
of part shapes, sizes, and weights. Types of grippers used in industrial robot applications include the
following:

a) mechanical grippers: consisting of two or more fingers that can be actuated by the robot controller to
open and measure to grasp the work part.
b) vacuum grippers: In these suction cups are used to hold flat objects.
c) magnetized devices: Used for holding ferrous parts.
Mechanical grippers are the most common gripper type. Some of the innovations und advances in mechanical
gripper technology includes.
i. Dual grippers, consisting of two gripper devices in one end effector, which are useful for machine
loading and unloading.
ii. interchangeable fingers that can be used on one gripper mechanism. To accommodate different parts,
different fingers are attached to the gripper.
iii. Sensory feedback in the fingers that provide the gripper with capabilities such as; sensing the presence
of the work part or applying a specified limited force to the work part during gripping.
iv. Multiple fingered grippers that possess the general anatomy of a human hand.
v. Standard gripper products that are commercially available, thus reducing the need to custom-design a
gripper for each separate robot application.
2) Tools: Tools are used in applications where the robot must perform some processing operation on the
work part. The robot therefore manipulates the tool relative to a stationary or slowly moving object (e.g., work
part or subassembly). Examples of the tools used as end effectors by robots to perform processing applications
include:
a) spot welding gun
b) arc welding tool
c) spray painting gun
d) rotating spindle for drilling, routing. grinding, and so forth
e) assembly tool (e.g., automatic screwdriver)
f) heating torch
g) water jet cutting tool.
In each case, the robot must not only control the relative position of the tool with respect to the work as a
function of time, it must also control the operation of the tool. For this purpose. the robot must be able to
transmit control signals to the tool for starting, stopping, and otherwise regulating its actions.
Factors to be considered for Selecting a Gripper

Robotic Drives- Electric Drive, Pneumatic Drive, Hydraulic Drive
Actuators drive the mechanical linkages and joints of a manipulator, which can be various types of motors
and valves. The energy for these actuators is provided by some power source such as hydraulic, pneumatic, or
electric. There are three major types of drive systems for industrial robots:
I. Hydraulic drive system
II. Pneumatic drive system
III. Electric drive system
1. Hydraulic Drive System: The most popular form of the drive system is the hydraulic drive system because
hydraulic cylinders and motors are compact and allow for high levels of force and power, together with
accurate control. These systems are driven by a fluid that is pumped through motors, cylinders, or other
hydraulic actuator mechanisms. A hydraulic actuator converts forces from high pressure hydraulic fluid into
the mechanical shaft rotation or linear motion. Hydraulic robots are preferred in environments in which the
use of electric drive robots may cause fire hazards, for example, in spray painting.
Advantages
• A hydraulic device can produce an enormous range of forces
• without the need for gears, simply by controlling the flow of fluid
• Preferred for moving heavy parts
• Preferred to be used in explosive environments
• Self-lubrication and self-cooling
• Smooth operation at low speeds
• There is need for return line
Disadvantages
• Occupy large space area
• There is a danger of oil leak to the shop floor
2. Pneumatic Drive System: Pneumatic drive systems are found in approximately 30 percent of today’s robots.
These systems use compressed air to power the robots. Because machine shops typically have compressed air
lines in their working areas, the pneumatically driven robots are very popular. These robots generally have
fewer axis of movement and can carry out simple pick-and-place material-handling operations, such as picking
up an object at one location and placing it at another location. These operations are generally simple and have
short cycle times. The pneumatic power can be used for sliding or rotational joints.
Advantages
• Less expensive than electric or hydraulic robots
• Suitable for relatively less degrees of freedom design
• Do not pollute work area with oils
• No return line required
• Pneumatic devices are faster to respond as compared to a hydraulic
• system as air is lighter than fluid
Disadvantages
• Compressibility of air limits control and accuracy aspects
• Noise pollution from exhausts
• Leakage of air can be of concern

3. Electric Drive System: Electrical drive systems are used in about 20 percent of today’s robots. These
systems are servomotors, stepping motors, and pulse motors. These motors convert electrical energy into
mechanical energy to power the robot. Compared with a hydraulic system, an electric system provides a robot
with less speed and strength. Electric drive systems are adopted for smaller robots. Electrically driven robots
are the most commonly available and used industrial robots. There are three major types of electric drive that
have been used for robots:
a) Stepper Motors: These are used mainly for simple pick and place mechanisms where cost is more
important than power or controllability.
b) DC Servos: For the early electric robots, the DC servo drive was used extensively. It gave good power
output with a high degree of control of both speed and position.
c) AC Servos: In recent years, the AC servo has taken over from the DC servo as the standard drive.
These modern motors give higher power output and are almost silent in operation. As they have no
brushes, they are very reliable and require almost no maintenance in operation.
Advantages
• Good for small and medium size robots
• Better positioning accuracy and repeatability
• Less maintenance and reliability problems
Disadvantages
• Provides less speed and strength than hydraulic robots
• Not all electric motors are suited for use as actuators in robots
• Require more sophisticated electronic controls and can fail in high temperature, wet, or dusty
environments

WEEK 8
Day 03 Session
Robot Control systems
The motions of a robot are controlled by a combination of software and hardware that is programmed by the
user. Robots are classified by control method into servo and non-servo robots.
1. Non-Servo Controlled Robots: Non-servo control is a purely mechanical system of stops and limit
switches, which are pre-programmed for specific repetitive movements. This can provide accurate control for
simple motions at low cost. The motions of non-servocontrolled robots are controlled only at their endpoints,
not throughout their paths. Non-servo robots are often referred as “endpoint,” “pick and place,” or “limited
sequence” robots. These robots are used primarily for materials transfer.
Characteristics of non-servo robots include:
• Relatively high speed possible due to smaller size of the manipulator
• These robots are low cost and simple to operate, program, and maintain
• These robots have limited flexibility in terms of program capacity and positioning capability
2. Servo Controlled Robots: Servo control system is capable of controlling the velocity, acceleration, and
path of motion, from the beginning to the end of the path. It uses complex control programs. These systems
use programmable logic controllers (PLCs) and sensors to control the motions of robots. They are more
flexible than non-servo systems, and they can control complicated motions smoothly. Sensors are used in
servo-control systems to track the position of each of the axis of motion of the manipulator. Servo controlled
robots are classified according to the method that the controller uses to guide the end-effector. These are:
• Point- to Point control Systems
• Continuous Path Control
• Intelligent control
• Controlled Path Robots
• System Control
(a) Point-to-Point Control Robot (PTP): A point-to-point robot is capable of moving from one discrete
point to another within its working envelope. During point-to-point operation the robot moves to a position,
which is numerically defined, and it stops there. The end effector performs the desired task, while the
robot is halted. When task is completed, the robot moves to the next point and the cycle is repeated. Such
robots are usually taught a series of points with a teach pendant. The points are then stored and played back.
Applications: Point-to-point robots are severely limited in their range of applications. Common applications
include:
• Component insertion
• Spot-welding
• Hole drilling
• Machine loading and unloading
• Assembly operations
(b) Continuous-path (CP) Control Robot: In a continuous-path robot, the tool performs its task, while
the robot (its axes) is in motion, like in the case of arc welding, where the welding pistol is driven along the
programmed path. All axes of continuous path robots move simultaneously, each with a different speed. The

computer co-ordinates the speeds so that the required path is followed. The robot’s path is controlled by storing
a large number of spatial points in the robot’s memory during the teach sequence. During teaching, and while
the robot is being moved, the co-ordinate points in space of each axis are continually monitored and placed
into the control system’s computer memory. These are the most advanced robots and require the most
sophisticated computer controllers and software development. Applications: Typical applications include:
• Spray painting
• Finishing
• Gluing
• Arc welding operations
• Cleaning of metal articles
• Complex assembly processes
(c) Intelligent control robots: This type of robots not only programmable motion cycle but also interact
with its environment in a way that years intelligent. It taken make logical decisions based on sensor data
receive from the operation. There robots are usually programmed using an English like symbolic language not
like a computer programming language.
(d) Controlled-Path Robot: In controlled-path robots, the control equipment can generate paths of
different geometry such as straight lines, circles, and interpolated curves with a high degree of accuracy. Good
accuracy can be obtained at any point along the specified path. Only the start and finish points and the path
definition function must be stored in the robot's control memory. It is important to mention that all controlled-
path robots have a servo capability to correct their path.
(e) System Control Robots: Control systems help to control the movements and functions of the robot.
To understand the control system first we need to understand some terminologies used in robotics.
• State- output produce by a robotic system is known as a state. Normally we denote it by x, the state
depends on its previous states, stimulus (signals) applied to the actuators, and the physics of the
environment. The state can be anything pose, speed, velocity, angular velocity, force and etc.
• Estimate- Robots cannot determine the exact state x, but they can estimate it using the sensors attached
to them. These estimations are denoted with y. It is the responsibility of the robotic engineer to select
good enough sensors or to calibrate the sensors well, such that they can produce y ~ x.
• Reference- the goal state we wish to achieve, it is denoted using r.
• Error- the difference between the reference and estimate is known as error.
• Control Signal- the stimulus produces/output by the controller is known as the control signal, it is
denoted using u.
• Dynamics- it is also called as the system plant/system model, it denotes how the system will behave
under non-static conditions. Dynamics are affected by the environment that may change or not always
linear. For example, floor type (concrete/wood), the air drags, slope and etc.
It is always the key responsibility of the engineer to build a controller, that reacts and produces control
signal u, such that e~0 & x~r.

Robotic Coordinate system using a robot
1. Joint co-ordinate system: This coordinate system determined by reference to
each moving joint. If the manipulator has six joints: J1 J2 J3 J4 J5 J6, all of which
are rotary joints. The positive rotation direction of each joint follows the right-
hand rule and the thumb points to the opposite direction of the output shaft of
each shaft motor
2. Rectangular co-ordinate system: These robots use the Cartesian
coordinate system (X, Y, and Z) for linear movements along the three axes
(forward and backward, up and down, and side to side). All three joints are
translational, which means the movement of the joint is restricted to going in
a straight line. This is why such robots are also called “linear” robots.
3. User or object or Work coordinate system: Work coordinates are
3-dimensional Cartesian coordinates defined for each operation space
of workpiece. The origin can be defined anywhere and as much as
needed. Work coordinates are expressed by the coordinate origin (X,
Y, Z) corresponding to the base coordinates and the angles of rotation
(RX, RY, RZ) around X, Y and Z axes of base coordinates. Up to
seven work coordinates can be defined and assigned work
coordinates. If work coordinates are not defined, base coordinates go
into effect.
4. Tool coordinate system: A tool mounting surface at the end of the robot arm
is called a flange. Three-dimensional Cartesian coordinates whose origin at
the center of the flange center are called mechanical interface coordinates.
The tool coordinates are 3-dimensional Cartesian coordinates whose origin
at the end of the tool mounted on the flange. Based on the origin of the
mechanical interface coordinates, the tool coordinates define the offset
distance components and axis rotation angles.

Steps to define user co-ordinate system.
• Defining X, Y, Z co-ordinate system
The user coordinate system is related to the essential points of the technological process. A robot can work
with different fixtures or working surfaces having different positions and orientations. A user coordinate
system can be defined for each fixture. If all positions are stored in object coordinates, you will not need to
reprogram if a fixture must be moved or turned. By moving (translating or turning) the user coordinate system
as much as the fixture has been translated or turned, all programmed positions will follow the fixture and no
reprogramming will be required. The user coordinate system is defined based on the world coordinate system
Verification and Validation Methods for Robotic Coordinate Systems: Verification & validation of
robotic systems is a challenging problem due to their complex and interactive architectures. Successful
operations of robots are not only depending hardware and software components but also their interaction with
the environment. Robots are systems that contains both mechanical and electronic hardware components. For
the successful interaction with the environment, robots use sensors to perceive their environment and actuators
that enable them to make changes in the environment. According to these perceptions, algorithms determine
the appropriate action and activate the actuators. All these systems; hardware, software, and interaction with
the environment should be considered for Verification & validation. Assuming all hardware units are working
as expected, at least V&V process should apply to the software component including the interaction with the
environment.
Software Engineering standards known as IEEE-STD-610 defines “Verification” as a test of a system to prove
that it meets all its specified requirements at a particular stage of its development. On the other hand,
“Validation” is defined as an activity that ensures that an end product stakeholder’s true needs and expectations
are met. Verification and validation activities are typically performed at many different stages of development
process. Early-stage focusses more on verification activities like reviews and testing to check that the system
is being developed correctly. During final stage, validation activities are often mandatory to check that the
system provides its intended services.

WEEK 08
Day 04 Session
Jogging Practice on robot with different coordinate systems
RoKiSim 1.7: Robot Kinematics Simulator
Dear Students
RoKiSim is a free multi-platform educational software tool for 3D simulation of serial six-axis
robots developed at the Control and Robotics Lab of the École de technologie supérieure (Montreal,
Canada).
The user can jog the virtual robot in either its joint space or the Cartesian space (with respect to the
tool frame, the base frame, or the world frame), show the various reference frames and visualize all possible
robot configurations (solutions of the inverse kinematics) for a given pose of the end-effector. Orientations
can be represented in any of several common Euler angle conventions (such as those used by FANUC
Robotics, KUKA Robotics, Adept Technology), as well as in unit quaternions (used by ABB Robotics).
The RoKiSim package comes with several popular industrial robot models as well as with seven end-
effector tools. It is relatively easy to add new robot models, and quite trivial to add new end-effector tools (in
ASCII STL format). The package also comes with simulations of the three types of robot singularities (wrist,
elbow and shoulder) for some of the robot models. A simulation consists of an ASCII file with a *.sim
extension, containing a sequence of numerical values for the six articular variables, and another ASCI file
with an *rks extension, specifying the robot and its tool.
The robot simulation software also comes with the ability to import object geometries and place them
in the robot environment. An object must be defined in an ASCII STL file or an SLP file (same as STL format
but allows a different color for each facet). A set consisting of a robot, an end-effector tool, objects and their
poses with respect to the robot's base frame, a simulation file, as well as the choice of language and Euler
angle convention can be saved as a station. An example of such a station is provided with the package. The
software package also comes with the possibility to jog the robot in Cartesian mode using a Wii Motion Plus
controller. Finally, RoKiSim can be interfaced with other software (e.g., Matlab) using internal socket
messaging IP address 127.0.0.1, and port 2001.
Download address:
https://www.parallemic.org/RoKiSim.html#:~:text=RoKiSim%20is%20a%20free%20multi,sup%C3%A9rie
ure%20(Montreal%2C%20Canada).
With Regards
THANMAY J S

User Screen Controls
Once you have selected your preferred robot model, Euler angle convention, menu language, and, optionally,
an end-effector, objects and a simulation, you can save them as default by selecting the option "Save as default
station" in the File menu.
Changing the view orientation
• Rotate: press the left mouse button while dragging the mouse.
• Pan: press Ctrl + the left mouse button while dragging the mouse.
• Zoom: press Shift + the left mouse button while dragging the mouse or use the mouse wheel button.
Playing simulations
To load a simulation, press Ctrl+D. Then, use the simulation panel at the bottom of the RoKiSim window (the
visibility of this panel can be toggled by pressing F4) or the following shortcuts:
• ↓: starts the simulation that has already been loaded.
• ↑: stops the simulation and brings the robot to its home configuration.
• →: stops the simulation and advances one step forward.
• ←: stops the simulation and advances one step backward.
Screen Panel Control
F2 for the Robot control panel, F3 for the Objects panel, and F4 for the Simulation panel

Simple Steps to Jog the Robot
Step 01: Select any Robot and Select Front View for Initial Position
Step 02: Slect Either Joint Jog or Cartician Jog for Setting the Tool to the required position
Step 03: Change to Left or Right-side view and use Joint Jog or Cartician Jog for Setting the Tool to the
required position

WEEK 08
Day :05 Session
Developmental Weekly Assessment + Industry Assignment
WEEK 08
Day 06 Session
Industry Class on interfacing of Robots with peripheral devices + Industry Assignment

Automation and Robotics Week 08 Theory Notes 20ME51I.pdf

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