HOA1&2 - Module 3 - PREHISTORCI ARCHITECTURE OF KERALA.pptx
Introduction to Robotics
1. Course Name: Introduction to Robotics
Course Code: MC2080
Wednesday, June 23, 2021 1
Course Instructor : Dr. Princy Randhawa
Department of Mechatronics Engg.
Manipal University Jaipur
2. Course Syllabus
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Introduction to robotics, sensors, actuators, transmission and drives
used in robotic systems, power, torque, force calculations for robotic
systems, degrees of freedom (DOF), robot configuration, spatial
resolution, accuracy and repeatability, robot specifications, structure
of robotic system, robot motion analysis, robot dynamics and control,
trajectory planning, features of future robots, interactions of robots
with other technologies, characteristics of future robot tasks, robots
in construction trades, coal mining, utilities, military and fighting
operations, under sea robots, robots in space, service industry and
similar applications.
3. Course Outcome
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MC2080.1 Outline the basics of robot structure, its classification, and specification
and robot drive systems.
MC2080.2 Study of type of sensors, their construction and working principle and
their application as per industrial robotic requirement.
MC2080.3 Study of robot motion analysis. To predict the position of robotic joint,
links, gripper with desired input.
MC2080.4 Study of statics and dynamics of robotic arm, and trajectory planning
using simple mathematical equations of dynamics.
MC2080.5 Learn various applications of robots in various environments.
4. Books/References
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1. K Sun Fu, Gonzalez, Robotics- Control, Sensing, Vision, and
Intelligence, McGraw-Hill, 2nd edition, 2010.
2. Deb SR, Deb S., Robotics technology and flexible automation,
Tata McGraw-Hill Education, 1994.
Reference Books:
1. John, J. Craig, Introduction to Robotics – Mechanics and Control,
Pearson Education International, 3rd edition, 2004.
2. Yu Kozyhev, Industrial Robots Handbook, MIR Publishers, 1985.
5. Marks Scheme
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30 Marks –Sessional I & 2
30 Marks Assignment- 15 Marks- Quiz
- 15 Marks- Seminar
40 Marks –End Semester
.
6. Wednesday, June 23, 2021 6
Few Questions to be Answered
What is a Robot?
What is Robotics?
Why do we Study Robotics?
How can we Teach a Robot to perform a particular Task?
What are possible applications of robots?
Can a human being be replaced by a robot
and so on
7. What do you come up with first
when you think of Robotics
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Mechanical Machines
Companions/Friends
Pets/Toys
Helpers
Dangerous Machines
10. Wednesday, June 23, 2021 10
A brief History of Robotics
Year Event and Development
1954 First patent on manipulator by
George Devot, the father of robot
1956 Joseph Engelberger started the
first robotics company: Unimation
1962 General Motors used the
manipulator: Unimate in die-casting
application
1967 General Electric Corporation made
a 4-legged vehicle.
11. Wednesday, June 23, 2021 11
Year Event and Development
1969 SAM was built by the NASA, USA
Shakey an intelligent mobile robot, was built
by Stanford Research Institute (SRI)
1970 Victor Scheinman demonstrated a
manipulator known as Stanford Arm
Lunokhod I was built and sent to the moon
by USSR
ODEX 1 was built by Odetics
1973 Richard at CMU, USA of Chincinnati Milacron
Corporation manufactured T3 (The tomorrow
tool ) robot
1975 Raibart at CMU, USA , built a one-legged
hoping machine, the first dynamically stable
machine
1978 Unimation developed PUMA (Programmable
Universal Machine for Assembly)
12. Wednesday, June 23, 2021 12
Year Event and Development
1983 Odetics introduced a unique experimental
six-legged device
1986 ASV (Adaptive Suspension Vehicle ) was
developed at Ohio State University , USA
1997 Pathfinder and Sojourner was sent to the
Mars by the NASA, USA
2000 Asimo Humanoid Robot was developed by
Honda
2004 The Surface of the Mars was explored by Spirit
and Opportunity
2012 Curiosity was sent to the Mars by the NASA,
USA
2015 Sophia (Humanoid) was built by Hanson
Robotics, Hong Kong
15. Laws of Robotics
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Asimov proposed three “Laws of Robotics”
Law 1: A robot may not injure a human being or
through inaction, allow a human being to come to harm.
Law 2: A robot must obey orders given to it by human
beings, except where such orders would conflict with
the first law.
Law 3: A robot must protect its own existence as long
as such protection does not conflict with the first law.
16. Wednesday, June 23, 2021 16
What is the definition of Robot
To be called a robot it should do some or all of the following
- Move Around
- Sense and Manipulate the Environment
- Display Intelligent Behaviour
Is a CNC Machine a Robot?
17. Wednesday, June 23, 2021 17
Definitions
The Term: Robot has come from the Czech word :
Robota, which means forced or Slave labourer.
In 1921,Karel Capek, a Czech playright, used the
term: robot first in his drama named Rosum’s
Universal Robots (R.U.R)
According to Karl Capek, a robot is a machine look-
wise similar to a human being
18. Wednesday, June 23, 2021 18
According to Literature, Robot has been defined in various ways
According to Oxford English Dictionary
A machine capable of carrying out a complex series of actions automatically,
especially one programmable by a computer.
According to International Organization for Standardization (ISO):
An automatically controlled, reprogrammable, multipurpose manipulator
programmable in tree or more axis, which can be either fixed in place or mobile
for use in industrial automation applications.
According to Robotic Institute of America (RIA)
It is a reprogrammable multifunctional manipulator designed to move materials,
parts, tools or specialized devices through variable programmed motions for the
performance of a variety of tasks.
19. Wednesday, June 23, 2021 19
Robotics
It is a science, which deals with the issues related to
design, manufacturing, usages of robots.
In 1942, the term: Robotics was introduced by Issac
Asimov, in his story named Run-around.
In Robotics, we use the fundamentals of Physics,
Mathematics, Mechanical Engg, Electronics Engg.,
Electrical Engg, Computer Sciences, and others
20. Wednesday, June 23, 2021 20
Three generation of Robotics/ Engineering
First Generation of Robots: simple pick and place
devices wit no external sensors
Second Generation of Robots: External Sensors (vision,
tactile, etc. ) for interaction with the environment
Third Generation of Robots: Intelligence, smart
material, bio, etc.
Future Robots: bio robots, micro, nano, cybogs, aneroids
etc.
21. Wednesday, June 23, 2021 21
3 Hs in Robotics
3 Hs of human beings are copied into Robotics, such as
HAND
HEAD
HEART
22. Anatomy of Robot
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Anatomy Representation
Body Base
Chest Link
Shoulder Joint
Upper Arm Link
Elbow Joint
Fore-arm Link
Wrist Joint
23. Automation and Robotics
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Motivation
To Cope with increasing demands of a dynamic and competitive
market, modern manufacturing methods should satisfy the following
requirements:
Reduced Production Cost
Increased Productivity
Improved Product Quality
Notes
[1] Automation can help to fulfil the above requirements
[2] Automation: Either Hard or flexible automation
[3] Robotics is an example of flexible automation
24. Types of Robots
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Robots can be classified by two types
Robots by Locomotion Robots by Application
25. Types of Robots
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25
Robots
by
Locomotion
Stationary Robots
Wheeled Robots
Legged Robots
Swimming Robots
Modular Robots
Micro Robots
Rolling Robotic Balls
Snake Robots
26. Types of Robots
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26
Robots
by
Application
Industrial Robots
Domestic Robots
Medical Robots
Military Robots
Space Robots
Hobby and Competition
28. Types of Robots
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Industrial Robots
–Materials handling
–Welding
–Inspection
–Improving productivity
–Laboratory applications
29. Types of Robots
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Mobile Robots
–Robots that move around on legs, tracks or wheels.
E.g.-
In 1979 a nuclear accident in the USA caused a leak of radioactive
material which led to production of special robot –which can handle
the radioactive materials
30. Types of Robots
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Educational Robots
Robotic kits are used extensively in
education.
E.g.-Robolab, Lego and RoboCup
Soccer
Domestic Robots
Those designed to perform household
tasks and modern toys which are
programmed to do things like talking,
walking and dancing, etc.
34. Interdisciplinary areas of Robotics
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Mechanical Engineering
Kinematics: Motion of the robot arm without
considering the force/and or moments
Dynamics: Study of the force/and or moments
Sensing: Collecting information of the environment
Computer Science
Motion Planning: Planning the course of action
Artificial Intelligence: To design and develop
suitable brain for the robot
35. Interdisciplinary areas of Robotics
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Electrical/Electronics Engineering
Control Schemes and Hardware Implementations
General Sciences
Physics
Mathematics
36. Overview of Robots
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Degree of Freedom
The Reference Frames
Robot Joints
Configurations
Robot Components
Robot Specifications
Modes of Programming and Control
38. A Robotic system Components
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Base
Links and Joints
End-Effectors/
Gripper
Wrist
Driver/Actuators
Sensors
Controllers
Software and
Hardware
39. Manipulator
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Manipulator is a main body for the robot and consists of the joints,
links
and other structural elements of the robot.
• It is a collection of mechanical linkages (or link) connected by
joints and
included are gears, coupling devices, and so on.
• Generally, joints of a manipulator fall into two classes:
▫ revolute (rotary)
▫ prismatic (linear).
• Each of the joints of a robot defines a joint axis along which the
particular link either rotates or slides (translates).
• Every joint axis identifies a degree of freedom (DOF)
Degree of Freedom= No. of Joints
40. Manipulator
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• Regardless of its mechanical configuration, the manipulator
defined by the joint-link structure generally contains three main
structural elements as human parts:
the arm
the wrist
the end effector.
• Most robots are mounted on stationary base on the floor and its
connection to the first joint as called link 0. The output link of
joint 1 is link 1, and so on.
41. End Effector
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• End effector is the part that is connected to the last joint (hand) of a manipulator,
which generally handles objects, makes connection to other machines, or performs
the required tasks.
• Robot manufacturers generally do not design or sell end effectors; just supply a
simple gripper.
• This is the job of a company's engineers or outside consultants to design and install
the end effector on the robot and to make it work for the given situation/task.
• In most cases, either the action of the end effector is controlled by the robot's
controller, or the controller communicates with the end effector's controlling device
such as a PLC.
• The end effectors can include a sensor to determine if a part is present.
• The addition of a simple sensor can make a gripper a relatively intelligent device.
42. Actuators
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Actuators are used to move elements of the manipulators.
• It must have enough power to accelerate and decelerate the links and
to carry the loads, yet be light, economical, accurate, responsive, reliable,
and easy to maintain.
• Each actuator is driven by a controller.
• Common types of actuators are electric motors (servomotors and stepper
motors), pneumatic cylinders, and hydraulic cylinders.
• Electric motor especially servomotors are the most commonly used.
• Hydraulic systems were very popular for large robots in the past and
still around in many places, but are not used in new robots as often any
more.
• Pneumatic cylinders are used in robots that have on-off type joints, as
well as for insertion purposes.
43. Sensors
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Adding sensors to an industrial robot can increase the range of
tasks the robot can perform.
• It also decreases the mechanical tolerances required of both the
robot and the robot’s environment.
• Sensors can be divided into three categories:
Internal sensors: tell a robot the position of its various joints and
report other conditions such as fluid pressure and temperature.
External sensors: tell the robot what is happening outside.
Interlocks: used to protect both humans and robots. They may
possess features of both internal and external sensors.
44. Controller
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The controller receives its data from the computer,
controls the motions of the actuators, and coordinates the
motions with the sensory feedback information.
45. Teach Pendant
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The robot will move to various locations in
performing its tasks.
These locations can be determined by a
controller system whenever then robot’s
working environment is defined.
However, these locations are usually taught
to the robot controller and used by the
operator to move the robot to desire
locations.
Teach pendants sometimes can also be
used to issue other commands to the robot
or to teach a relatively simple program.
46. Robot Joints
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The Robot Joints is the important element in a robot which helps the links to travel
in different kind of movements. A joint in an industrial robot is similar to that in a
human body. It provides with a relative motion between two parts.
Different types of Joints
1. Linear- Sliding and Prismatic Joint
2. Rotary: Twisting or Revolute Joint
47. Robot Joints
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The Robot Joints is the important element in a robot which helps the links to travel
in different kind of movements. A joint in an industrial robot is similar to that in a
human body. It provides with a relative motion between two parts.
Different types of Joints
1. Linear- Sliding and Prismatic Joint
2. Rotary: Twisting or Revolute Joint
57. Degree of Freedom
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It is defined as the minimum no. of independent parameters,
variables, coordinates needed to describe a system completely
Note:
A point in 2-D:2 DOF, IN 3-D space: 3DOF
A rigid body in 3-D: 6 DOF
Spatial Manipulator:6 DOF
Planar Manipulator:6DOF
58. Redundant Manipulator
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Either a spatial manipulator with more than 6 DOF or a planar
manipulator with more than 3 DOF
Under Actuated Manipulator
Either a spatial manipulator with less than 6 DOF or a planar
manipulator with less than 3 DOF
59. Mobility / DOF of Spatial
Manipulator
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Let us consider a manipulator with n rigid moving links and m joints
Ci= Connectivity of i-th joint, i=1,2,3,…………….m
No. of Constraints put by the i-th joint=
Total no. of Constraints =
Mobility of the manipulator
It is known as Grubler’s Criterion.
60. Mobility / DOF of Planar
Manipulator
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Let us consider a manipulator with n rigid moving links and m joints
Ci= Connectivity of i-th joint, i=1,2,3,…………….m
No. of Constraints put by the i-th joint=
Total no. of Constraints =
Mobility of the manipulator
It is known as Grubler’s Criterion.
64. Robot Configurations
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Cartesian (3P) Robots
Linear movement along three different axes
Have either sliding or prismatic joint that’s
SSS or PPP
Rigid and accurate
Suitable for pick and place type of
operations
Examples: IBMs RS-1, Sigma robot
66. Advantages
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66
Cartesian/Gantry
Robots
Rigid Structure of box frame type
High Repeatability with least error
High Load carrying capability
67. Robot Configurations
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Cylindrical (2PR) Robots
Two Linear and one rotary movements
Represented as TPP, TSS
Used to handle parts/objects in
manufacturing
Cannot reach the objects lying on the floor
Poor dynamic performance
Examples: Versatran 600
68. Advantages
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68
Cylindrical
Robots
High rigidity of the manipulator
Higher Load carrying capacity
Geometrical advantage in specification
69. Robot Configurations
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Spherical (2RP ) or Polar Coordinate Robots
One Linear and 2 rotary movement
Represented as TRP, TRS
Suitable for handling parts/objects in
manufacturing
Can pick up objects lying on the floor
Poor dynamic
Performance
Examples : Unimate 2000B
71. Advantages
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71
Spherical
Robots
Higher Reach from the base
Geometric advantage in specification
Machine Loading applications need this type.
74. Robot Configurations
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Articulated/ Revolute Coordinate(3 R) Robots
Rotary Movement about three independent axes
Represented as TRR
Suitable for handling parts/components in
manufacturing system
Rigidity and accuracy may not be good enough
Examples; T3, PUMA
75. Advantages
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75
Articulated
Robots
Higher reach from the base
Useful in continues path generation, applied to spray
painting and are welding.
Reaching the conjested small openings without
interference
79. Resolution, Accuracy and
Repeatability
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Resolution: It is defined as the smallest allowable position increment of
a robot
Programming Resolution: Smallest allowable position increment in
robot programme
Basic Resolution Unit (BRU)= 0.01 inch/0.1 degree
Control Resolution: Smallest Change in position that the feedback
device can measure say 0.36 degrees per pulse
80. Resolution, Accuracy and
Repeatability
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Accuracy: It is the precision with which a computed point can be
reached
Repeatability: It is defined as the precision wit which a robot re-
position itself to a previous taught point.
81. Applications
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In manufacturing Units
Advantages of Robots
Robots can work in hazardous and dirty environment
Can increase productivity after maintaining improved quality
Direct Labour cost will be reduced
Material cost will be reduced
Repetitive tasks can be handled more effectively
Arc Welding
Spot Welding
Spray painting
Pick and Place operation
Grinding
Drilling
Milling
82. Applications
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Under Water Applications
Purposes
To explore various resources
To study under-water environment
To carry out drilling, pipe line survey, inspection and repair of ships
Note:
Robots are developed in the form of ROV(Remotely Operated
Vehicle) and AUV (Autonomous Under-Water Vehicle)
Robots are equipped with sensors, propellers/thrusters, on-board
software's and others
83. Applications
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Medical Applications
Tele-surgery
Micro-capsule multi-legged robots
Prosthetic Devices
Space Applications
For carrying out on-orbit services, assembly job and interplanetary
missions
Spacecraft deployment and retrieval , survey of outside space
shuttle, assembly, testing, maintenance of space stations, transport
of astronauts to various locations
Robo-nauts
Free-Flying Robots
Planetary exploration rovers
84. Applications
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In Agriculture
For Spraying pesticides
For spraying fertilizers in liquid form
Cleaning weeds
Sowing seeds
Inspection of plants
Other Applications
Replacement of maid-servant
Garbage Collection
Underground Coal mining
Sewage-line cleaning
Fire Fighting etc.
85. End Effectors
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An end-effector is a device attached to the wrist of a
manipulator for the purpose of holding materials, parts, tools
to perform a specific task.
Grippers: End Effector used to grasp and hold objects
Tools: End effectors designed to perform some specific
tasks
E.g. Spot Welding electrode, Spray Gun
86. Classification of Grippers
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1. Single Gripper and Double Gripper
o Single Gripper: Only one gripping device is mounted on the wrist
o Double Gripper: Two independent gripping devices are attached to
the wrist
Example: Two separate grippers mounted on the wrist for loading and
unloading applications
88. Classification of Grippers
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3. Hard Gripper and Soft Gripper
o Hard Gripper: Point contact between the finger and the object
o Soft Gripper: Area (surface) contact between the finger and the
object
89. Classification of Grippers
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3. Active Gripper and Passive Gripper
o Active Gripper: Gripper equipped with sensor
o Passive Gripper: Gripper without sensor
90. A few Robot Grippers
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1. Mechanical Gripper
o Use mechanical fingers (jaws) actuated by some mechanism
o Less versatile, less flexible and less costly
Example: i) Gripper with Linkage Actuation
91. A few Robot Grippers
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ii ) Gripper with Rotary Actuation
92. A few Robot Grippers
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ii ) Gripper with cam Actuation
93. A few Robot Grippers
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2 ) Vacuum Grippers/Suction Gripper (used for thin parts)
https://www.youtube.com/watch?v=h7MpTfmNCAo
94. A few Robot Grippers
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Suction cup is made up of elastic material like rubber or soft plastic
When the object to be handled is soft, the cup should be made of
hard substance
Two Device can be used: Either Vacuum pump or Venturi
95. A few Robot Grippers
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3. Magnetic Gripper (for magnetic materials only.
For example: various steels but not stainless steel
Can use either electromagnets or permanent magnets
Pick up time is less
Can grip parts of various sizes
Disadvantage: residual magnetism
Stripping Device: for separating the part from the permanent
magnet
For separating the part from the electro-magnet, reverse the
polarity
99. Passive Gripper
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Solution: Use Remote Centre Compliance (RCC)
RCC is inappropriate for assembly of pegs in horizontal direction
Insertion angle must less than 45 degrees
Cannot be used in chamferless insertion tasks
https://www.youtube.com/watch?v=qFTUFHGGZIg
100. Gripper Selection and Design
Requirements
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The gripper must have the ability to reach the surface of a work part.
The change in work part size must be accounted for providing accurate
positioning.
During machining operations, there will be a change in the work part size. As a
result, the gripper must be designed to hold a work part even when the size
is varied.
The gripper must not create any sort of distort and scratch in the fragile
work parts.
The gripper must hold the larger area of a work part if it has various
dimensions, which will certainly increase stability and control in positioning.
The gripper can be designed with resilient pads to provide more grasping
contacts in the work part. The replaceable fingers can also be employed for
holding different work part sizes by its interchangeability facility
101. Tips for Designing a Gripper
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-Gripper with passive finger
-Gripper with active feedback
102. Gripper with passive finger
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Choose acc. to the task to be performed and the geometry and
characteristics of parts to be grasped.
Consider the local environments, working space, conveyor
positions etc.
Determine the no. of joint links and there config. By part
geometry and task movements
Decide the material of construction based on type of duty,
corrosion resistance or heat geometry and task movements.
Select proper actuators--- hydraulic for high forces, electric
motors for best control, Pneumatic for less cost and ease etc.
103. Gripper with active feedback
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Use sensor based robots to handle heavy parts.
Use active wrist with passive fingers to handle forces
greater than 1 to 2-5 kg
106. Robot Teaching
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To provide necessary instruction to the load
Teaching Methods
Online Methods Offline Methods
Manual Teaching Lead Through Teaching
(Point to Point task)
Control Handle/Joystick
Push buttons
Teach-pendant
(Continuous path task)
Robot Simulator
Programming Language
107. Robot Teaching
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Offline Method
VAL Programming for PUMA
Task: Pick and Place Operations
VAL Program Other VAL Commands
APPRO PART, 100 SPEED 40
MOVES PART EXECUTE
CLOSEI ABORT
DEPARTS 200 EDIT Filename
APPROS BIN, 300 LISTF
MOVE BIN STORE
OPENI DELETE
DEPART, 100 LOAD Filename
108. Robotic Specification
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Control Type
Drive System
Coordinate System
Teaching/Programming Methods
Accuracy/Repeatability, Resolution
Pay-Load Capacity
Weight of the Manipulator
Range and Speed of arms and wrist
Applications
Sensor Used
109. Economic Analysis
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Let F : Capital Investment to purchase a robot which includes
its purchasing Cost and installation Cost
B: Saving in terms of Material and Labour Cost
C: Operating and Maintenance Cost
D: Depreciation of the Robot
A: Net Savings
A=B-C-D
G: Tax to be paid on the Net Savings
Pay-back period, E = (Capital Investment, F)/ (B-C-G)
110. Economic Analysis
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Let I : Modified net savings after the payment of tax
Rate of return on investment
H=(I/F)*100%
A Company decides to purchase the robot, if
Pay-back period < techno-economic life
Rate of return on investment > Rate of bank interest
111. Numerical Example
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The cost and savings associated with the robot installation are given below:
Costs of a robot including accessories : Rs. 12, 00,000
Installation Cost: Rs. 3,00,000
Maintenance and operating cost: Rs. 20 per hour
Labour Saving: Rs. 100 per hour
Material Saving : Rs. 100 per hour
The shop runs 24 hours in a day (3 shifts) and the effective workdays in a
year are 200. The tax rate of the company is 30% and techno economic life
of the robot is expected to be equal to six years .
Determine
a) pay-back period of the robot and
b) Rate of return on investment
112. Solution
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Capital investment F= Cost of the robot including accessories
+installation cost = Rs. 15,00,000
Total hours of the running of the robot per year =24*200= 4800
Saving per year B= Labour Saving + Material Saving
=100*4800+15*4800
=Rs. 5,52,000
Maintenance and Operating cost per year C = 20*4800 = Rs. 96,000
Techno–economic life of the robot = 6 years
113. Solution
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Constant Depreciation per year= Rs. 15,00,000/6 =Rs. 2,00,000
Net Savings= Savings- Operating Cost- Depreciation
= 5,52,000-96,000-2,00,000
= Rs. 2, 56,000
Tax To Be Paid To The Government by the company G=30% of A
=Rs. 76,800
Pay-back period of the robot
E= (F/B-C-G)=3.9 years < techno-economic life
114. Solution
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Net savings after the payment of the tax
I= 0.7* 2,56,000
= Rs. 1,79,200
Rate of return on investment
H= I/F*100 =11.95%> Rate of bank interest
Therefore, the purchase of the robot is justified by taking the loan
from the bank
115. Sensors
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Human beings collect information of the surroundings
using their sensors namely, eyes, ears, nose, skin, etc. in
order to perform various tasks.
A sensor is used to take measurement of physical variable.
A sensor requires calibration
Sensors are used to build intelligent robots.
116. Sensor vs Transducer
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Transducer = primary measuring element + secondary measuring
element
i.e. Transducer = Sensor + Signal conditioning circuit
117. Classification of Sensors
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Sensors
Internal Sensors
(used to operate the drive units)
Example: Position sensors
Velocity Sensors
Acceleration Sensors
Force/Moment Sensors
External Sensors
(used to collect the information
Of the environment)
Example: Temperature Sensor,
Visual Sensor, Proximity
Sensor, Acoustic Sensor
118. Classification of Sensors
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Sensors
Contact Sensors
(Physical contact between
sensor mounted on robot and
object)
Non Contact Sensors
(No Physical Contact)
Example: Visual Sensor,
Proximity Sensor, Acoustic Sensor,
Range Sensor
Touch Sensor/ Tactile
Sensor/Binary Sensor
(indicate presence or
absence of an object)
Example: Micro switch,
Limit Switch
Force Sensor/ Analog Sensor
(not only the contact is made but also the force is
measured)
Sensors using strain gauges
119. Characteristics of Sensors
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Range: Difference between maximum and minimum values of the
input that can be measured.
Response: Should be capable of responding to the changes in
minimum time.
Accuracy: Deviation from exact quantity
Sensitivity: Changes in output/change in input
Linearity: Constant Sensitivity
Repeatability: Deviation from reading to reading , when these are
taken from a number of times under identical conditions
Resolution
120. Characteristics of Sensors
Wednesday, June 23, 2021 120
Touch Sensor
Used to indicate whether contact has been made between two
objects
Does not determine the magnitude of contact force
Example: Micro switch, Limit switch
121. Sensors
Wednesday, June 23, 2021 121
Connected to Robot wrist
Micro-switches
Finger
Figure: Micro switches placed on two fingers of a robotic hand
122. 1. Position Sensor
Wednesday, June 23, 2021 122
Potentiometer
Linear Potentiometer Angular Potentiometer
Angular Potentiometer
123. Angular Potentiometer
Wednesday, June 23, 2021 123
For the known values of Vin R, Vout f (r)
By measuring Vout, r can be determined and an angular displacement θ.
Demerits
Resistance of the wire is temperature dependent
Potentiometer is temperature sensitive
124. 2. Optical Encoder
Wednesday, June 23, 2021 124
Optical Encoder
Absolute Optical Encoder Incremental Optical Encoder
Absolute Optical Encoder
It is mounted on the shaft of a
rotary device
To generate digital word
identifying actual position of
the shaft measured from zero
position
126. Incremental Optical Encoder
Wednesday, June 23, 2021 126
Consists on one coded disc and two
photo detectors
By counting the number of light and
dark zones, angular displacement can
be measured with respect to known
starting position
It can determine the direction of
rotation also.
It is construction-wise simpler, less
accurate and less simpler
127. Linear Variable Differential
Transformer (LVDT)
Wednesday, June 23, 2021 127
It consist of two parts: fixed casing
and moving magnetic core
In between the fixed casing and
magnetic core, there are one primary
and two secondary coils
Produced voltage output is
proportional to the displacement of
moving part relative to the fixed base
Ac voltage is applied to the Lp.
Ls1 and Ls2 are connected in series
Vout=LS2-LS1
129. Force/Moment Sensor
Wednesday, June 23, 2021 129
Strain gauge is connected to potentiometer circuit, whose
output voltage is proportional to the deflection and hence ,force
Three component of force (F) and moment (M) each are
determined by adding and subtracting the respective
components of force.
F=CMW
Readings of the strain
gauge
Forces/Moments
Calibration Matrix
130. Force/Moment Sensor
Wednesday, June 23, 2021 130
Precautions
Strain gauges are to be properly mounted on the deflection bars
Sensors should be operated within the elastic limit of its material
(deflection bars)
131. Range Sensor
Wednesday, June 23, 2021 131
It measures the distance between the sensor (detector) mounted
on the robots body and the object
132. Proximity Sensor
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Proximity Sensor
Inductive Sensor Hall Effect Sensor Capacitive Sensor
Inductive Sensor
It consist of a permanent magnet and a
wound coil placed next to it.
The nature of flux lines changes as the
sensor come closer to a ferro-magnetic
material
The flux lines changes, as the ferro-
magnetic object either leave or enters the
field of magnet.
Rate of change of magnetic flux is
proportional to induced current
(voltage)
133. Inductive Sensor
Wednesday, June 23, 2021 133
Voltage induced across the coil depends on the speed at which the
object either enter or leaves the magnetic field.
Polarity of the voltage depends on whether the object enters or leaves
the field.
134. Calibration Curve
Wednesday, June 23, 2021 134
The Figure shows the calibration curve corresponding to the
measured amplitude of voltage signal, the distance between the
sensor and the object can be determined
135. Hall effect Sensor
Wednesday, June 23, 2021 135
It works based on the principle of Lorentz force.
If a charge of amount q is moving with velocity in a magnetic field
strength of field , then the Lorentz force,
136. Inductive Sensor
Wednesday, June 23, 2021 136
Voltage across the
semiconductor will be reduced
Calibration curve for hall effect
sensor
137. Capacitive Sensor
Wednesday, June 23, 2021 137
When an object brought near to
the sensitive electrode , there will
be accumulation of charge and
consequently its capacitance
changes.
When the capacitance of the
sensor exceeds a predefined
threshold value, oscillation starts.
Oscillations are converted into
output voltage through PCB.
Calibration curve
139. Light Sensor
Wednesday, June 23, 2021 139
A Light sensor is used to detect light and create a voltage difference. The two main light
sensors generally used in robots are photo resistor and Photovoltaic cells.
Types of Light Sensor
VEX light sensor
LEGO light sensor
Light Sensor 1000 lux
SCI-BOX Light Detector
TAOS TSL235R Light to Frequency Converter
Parallax QTI Sensor
DFRobot Ambient Light Sensor
Arduino LilyPad light sensor
DFRobot BH1750 light sensor
CdS photoconductive cell
140. Light Sensor
Wednesday, June 23, 2021 140
A Light sensor is used to detect light and create a voltage difference. The two main light
sensors generally used in robots are photo resistor and Photovoltaic cells.
Types of Light Sensor
VEX light sensor
LEGO light sensor
Light Sensor 1000 lux
SCI-BOX Light Detector
TAOS TSL235R Light to Frequency Converter
Parallax QTI Sensor
DFRobot Ambient Light Sensor
Arduino LilyPad light sensor
DFRobot BH1750 light sensor
CdS photoconductive cell
142. Sound Sensor
Wednesday, June 23, 2021 142
This sensor (generally a microphone) detects sound and returns a voltage proportional
to the sound level. A simple robot can be designed to navigate based on the sound it
receives. Imagine a robot which turns right for one clap and turns left for two claps.
Complex robots can use the same microphone for speech and voice recognition.
143. Temperature Sensor
Wednesday, June 23, 2021 143
What if your robot has to work in a desert and transmit ambient temperature?
Simple solution is to use a temperature sensor. Tiny temperature sensor ICs
provide voltage difference for a change in temperature. Few generally used
temperature sensor IC’s are LM34, LM35, TMP35, TMP36, and TMP37.
144. Contact Sensor
Wednesday, June 23, 2021 144
Contact sensors are those which require physical contact against other objects
to trigger. A push button switch, limit switch or tactile bumper switch
are all examples of contact sensors.
145. Pressure Sensor
Wednesday, June 23, 2021 145
Pressure sensor measures pressure. Tactile pressure sensors are useful in robotics as
they are sensitive to touch, force and pressure. If you design a robot hand and need
to measure the amount of grip and pressure required to hold an object, then this is
what you would want to use.
146. Tilt Sensor
Wednesday, June 23, 2021 146
Tilt sensors measure tilt of an object. In a typical analog tilt sensor, a small amount of
mercury is suspended in a glass bulb. When mercury flows towards one end, it closes
a switch which suggests a tilt.
147. Distance (Proximity) Sensor
Wednesday, June 23, 2021 147
Most proximity sensors can also be used as distance sensors.
Type of distance sensor:
Ultrasonic Distance Sensors
Infrared Distance sensor
Laser range Sensor
Encoders
Stereo Camera
148. Distance (Proximity) Sensor
Wednesday, June 23, 2021 148
Most proximity sensors can also be used as distance sensors.
Type of distance sensor:
Ultrasonic Distance Sensors
Infrared Distance sensor
Laser range Sensor
Encoders
Stereo Camera
149. Voltage Sensor
Wednesday, June 23, 2021 149
Voltage sensors typically convert lower voltages to higher voltages,
or vice versa. One example is a general Operational- Amplifier (Op-
Amp) which accepts a low voltage, amplifies it, and generates a
higher voltage output.
150. Current Sensor
Wednesday, June 23, 2021 150
Current sensors are electronic circuits which monitor the current flow
in a circuit and output either a proportional voltage or a current.
151. IMU Sensor
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Inertial Measurement Units combine properties of two or more sensors such as
Accelerometer, Gyro, Magnetometer, etc., to measure orientation, velocity and
gravitational forces.
152. Difference between analog and Digital Sensor
Wednesday, June 23, 2021 152
An accelerometer is a device which measures acceleration and tilt.
There are two kinds of forces which can affect an accelerometer: Static
force and Dynamic Force.
153. Difference between analog and
Digital Sensor
Wednesday, June 23, 2021 153
A digital sensor can only have two
values: 1 or 0, all or nothing. An example
of a digital sensor is a button, which can
either have the value of 1 when pressed
or 0 when not pressed. On a ZUM board
or a similar one, the digital sensors will
be connected on the digital pins D0-D13.
An analogue sensor can have
multiple states and is able to
transform the quantity of light,
temperature or other physical
elements into a value between 0 and
1023.
Digital Sensor Analog Sensor
154. Wednesday, June 23, 2021 154
7 Types of Industrial Robot Sensors
2D Vision
3D Vision
Force Torque Sensor
Collision Detection Sensor
Safety Sensors
Part Detection Sensors
Others
155. Robot as a System
Wednesday, June 23, 2021 155
ROBOT
Working
environment
Commands Actions
Program
Task
Mechanical
Units
Actuation Units
Supervision
Units
Sensor Units
157. Actuator Components
Wednesday, June 23, 2021 157
Power
Supplies
Power
Amplifier
Motor
or
Servomotor
Transmission
(mechanical
gears)
Pp
Pc
Pa Pm Pu
Pda Pds Pdt
Actuator
Power Losses due to dissipation effect (friction)
Electric, Hydraulic or Pneumatic
158. Actuators
Wednesday, June 23, 2021 158
Electric Actuators: The Primary input power supply is the
electric energy from the electric distribution system.
Hydraulic Actuators: They transform hydraulic energy
stored in a reservoir into mechanical energy by means of
suitable pumps.
Pneumatic Actuators: They utilise pneumatic energy i.e.
compressed air, provided by a compressor and transform it
into mechanical energy by means of piston or turbines.
159. Electric Actuator Types
Wednesday, June 23, 2021 159
1. Servo Motor
2. DC-motors
3. Brushless DC-motors
4. Asynchronous motors
5. Synchronous motors
6. Reluctance motors
7. Stepper Motor
161. Electric Motor
Wednesday, June 23, 2021 161
Advantages
1. Good for all sizes of robots
2. Better control, good for high precision robots
3. Higher compliance than hydraulics
4. Reduction gears used to reduce inertia on the motor
5. Does not leak, good for clean room
6. Reliable, low maintenance
7. Can be spark free, good for explosive environments
Disadvantages
1. Low stiffness
2. Needs reduction gears, increased backlash, cost and weight
3. Motor needs braking device when not powered. Otherwise, the arm will fall
162. Electric Actuators
Wednesday, June 23, 2021 162
Mainly rotating but also linear ones are available
Linear movement with gear or with real linear motor
163. Pneumatic
Wednesday, June 23, 2021 163
Advantages
1. Many components are usually off the- shelf.
2. Reliable components.
3. No leaks or sparks.
4. Inexpensive and simple.
5. Low pressure compared to hydraulics.
6. Good for on-off applications and for pick and place.
7. Compliant systems.
Disadvantages
1. Noisy systems.
2. Require air pressure, filter, etc.
3. Difficult to control their linear position.
4. Deform under load constantly.
5. Very low stiffness and inaccuracy response.
6. Lowest power to weight ratio.
164. Hydraulic
Wednesday, June 23, 2021 164
Advantages
1 Good for large robots and heavy payload.
2. Highest power/weight ratio.
3. Stiff system, high accuracy, better response.
4. No reduction gear needed.
5. Can work in wide range of speeds without difficulty.
6. Can be left in position without any damage
Disadvantages
1. May leak and not fit for clean room applications.
2. Requires pump, reservoir, motor, hoses, etc.
3. Can be expensive, noisy and requires maintenance.
4. Viscosity of oil changes with temperature.
5. Very susceptible to dirt and other foreign material in oil.
6. Low compliance.
7. High torque, high
165. Stepper Motor
Wednesday, June 23, 2021 165
1. A sequence of (3 or more) poles is activated in turn, moving
the stator in small “steps”.
2. Very low speed / high angular precision is possible without
reduction gearing by using many rotor teeth.
3. Can also perform a “micro-step” by activating both coils at
once.
184. Properties of Rotation matrix
Wednesday, June 23, 2021 184
Each row/column of a rotation matrix is a unit vector
Inner(dot) product of each row of a rotation matrix with each other row
becomes equal to 0. The same is true for each column also.
Rotation matrices are not commutative in nature.
Inverse of a rotation matrix is nothing but its transpose.
Sensor: input to the system, takes the information from the environement
Actuator: output from the system
Sensor: it can detect the physical signal and convert into electrical sisgnal. Robotic sensors are used to estimate a robot's condition and environment. These signals are passed to a controller to enable appropriate behavio
Actuators can be used to generate motion. Sensors in robots are based on the functions of human sensory organs. Robots require extensive information about their environment in order to function effectively.
Robot require a drive system for moving their wrist, arm and body.
The joints are moved by actuators powered by a particular form of drive system.
A drive system can be used to determine the capacity of the robot
Drives hydraulic uses pressurises hydraulic fluid ,
pneumatic:; used air as medium and especially for small type robots which has less than 5 dof and
electrical: uses external power like battery, capable of moving robots with high power or speed, the actuation can be done using dc servo motor, dc stepper motor.
Path planning is imp. For the performance of the automation system
A bipedal walking robot is a type of humanoid robot which mimics like human being and can be programmed to perform some tasks as required. ... This bipedal robot can assist human to carry out the tasks or activities in hazardous environment. This could eliminate human's risk of injury or life casualty.
Walking robots follow nature by being able to navigate rough terrain, or even climb stairs or over obstacles in a standard household situation, which would rule out most driving robots. Robots with six or more legs have the advantage of stability.
Spider: Hexapod Robot
Exploring dangerous and / or rough areas for humans • Exploring war zones • Inspecting unstable buildings after natural disasters such as an earthquake • Defusing bombs such as land mines
The snake robot can be used for many applications such as search and rescue operations in collapsed structure and inspection of tightly packed space that people and conventional machinery cannot access
.
This is just like a robot and we are going to give them a task and it is going to perform a task just like servant.
In that drama. He introduced the term robot. there robots look was similar to human beings.
During that time there was not a single robot in the world.
.
Only linear movement, 1 connectivity, 1 dof
Wth the help of thses joint we can represent manipulator
How to determine dof for different manipulator
N (no. of moving links)=4, no. of joint=4, c1=c2=c3=c4=1
If it has one connectivity then how many constraints =(3-Ci)- 3-1=2
3*4-8= 4 dof
Mobility/dof
no. of constraints = (3-Ci)=2
No, of joints =4
2*4 =8
So this is serial redundant planar manipulator
and dof= summation of ci so its true for serial planar manipulator but not for parallel
N=7, m=9
Ci=1
end effector=1 link
One link is going to give 6 constraints 6*3=18
so its ideal parallel planar manipulator
Top plate is also considered as one link
Plate is fixed to the ground
N=13, m=18
Now we need to find how many constraints put by one leg
Universal joint has 2 dof so 6-2=4 constraints
Prismatic =6-1-5
Spherical =6-2=3 so total 5+4+3=12 constraints
So 12*6=72 constraints
Its is an ideal parallel spatial manipulator so it can have 3 translational and 3 rotational motions. This is used for trainee of pilot in ana aircraft
In telesurgery: two robots 1 is master and other is slave robot. Slave robot is going to carry out operation on patient and in master robot, doctor is going to give instructions. There is a physical distance between patient and doctor. Slave robot is equipped with knives, scissors, force and torque sensors also mounted on it. And also the will be one control panel , once the slave robot is carry out operation then slave operation has to put some force, torque, moment and these are determined with force and torque sensors and using wireless connection that signal will send to doctor.
The robot is very small and equivalent to capsule and inside it has multi legged robot and it is equipped with high speed camera and just to indentify whether any kind of tumour inside the system.in this we do-not use any motor and control the movement through outside the body of patient by using permanent magnet. Size will be larger if we use motor. Camera needs power then we use very small lithium battery along with camera.at regular
interval it will take the pictures and send to doctor and it will identify the possible position of the tumour.
3. It is used in rehabilitation robots, we take the help of different types of robots.. Orthotic devices which will help the older people in walking, these are intelligent robots.
Space: they can collect the information of planets, multi-legged, tracked, in space station, they can use robots for maintenance, repairs. Later astronauts will be replaced wit robot
e.g. two vacuum gripper that is connected to robotic wrist. The cup is nothing but vacuum gripper. Now see how it works so go back to previous diagram
We do not use any sensor.
Principle: e.g. suppose I want to develop one Printed PCB and in that there are small-small holes, and in that depending on the requirements we insert small resistors, capacitors. If this take I give it to manipulator. then we have to use special type of gripper i.e. passive gripper.
This schematic diagram shows that in steel plate there are one circular hole. Suppose we need to insert the peg into hole…and it will collide and obstructed here that is known as lateral error
To remove that error we use chamfering and try to insert that peg into hole then there is a possibility that it will be solved of lateral error but again there will be a problem of orientation that is known as angular error.
So we can solve these 2 errors by using passive gripper
Purpose: if manufacturing unit want to purchase robot but it is costly if we go for 6 dof then it will 30 lakhs, 40 lakhs then it will take a loan and accordingly take a deciosn whther to take loan from bank or not so it has to carry out some analysis
d: Falling Value Of An Asset payback period: no. of years reqd. to get the money back which had spent
Techno economic life: intersection of technical life and economic life.
10 yrs+6 rs
Due to heating effect of the wire
H=i2rt
Then heat will generated in the wire and then temp increases and as temp increase then resistance changes
For 4 concentric rings
360/16= resolution
N=1/2^N
N=10=1/2^10
Delta= pL3/3EI
P=need to bed determined (load)
L=length of the beam
E=Young modulus
I- moment of inertia
6x8 : calibration matrix
a
It produce rotational movements in the form of finite steps. Used for small and medium robots and with teaching and hobby robot
A Stepper motor is a digital actuator where input is in the form of programmed energization of stator winding and output is in the form of discrete angular position.
Rotation of rotor occurs because of magnetic interaction between rotor pole and poles of sequentially energized stator winding.
Frame transformation means it includes frame translational and frame rotation.
So first we will see translation frame first so u can see x_b is parallel to x_u
Y_b is parallel to y_U
Z_b is parallel to z_u
But there is a shifting of origin. Suppose the position of particular point wrt b is known and other translational is also known then how to find Q wrt u so that is our aim
So If I know the position wrt body coordinate frame then we can find out the position information wrt universal coordinate system
Now to find the inverse of a matrix
Rolling about X axis
Pitching about Y axis
Yawing about Z axis
3 ROTATIONS
RPY-ROLL,PITCH,YAW
Negative- clockwise
Positive-anticlockwise
If u want to find the position and orientation of an end effector then u assign the coordinate system at each joint for that we nee Denavit Hartenberg notation.