Introduction to Robotics
Course
Semester 6
Code
AIT304
Completed
Difficulty
Syllabus
⭐⭐
Introduction to robotics – Degrees of freedom, Robot types- ManipulatorsAnatomy of a robotic manipulator-links, joints, actuators, sensors, controllers.
Robot configurations-PPP, RPP, RRP, RRR. Mobile robots- wheeled, legged, aerial
robots, underwater robots, surface water robots . Dynamic characteristics- speed
of motion, load carrying capacity & speed of response. Introduction to End
effectors - mechanical grippers, special tools, Magnetic grippers, Vacuum
grippers, adhesive grippers, Active and Passive grippers. Ethics in robotics - 3
laws - applications of robots.
Notes
Subject
NOTE by
Kingstan
Created
by
Email
Robotics and Intelligent System
The only module which was somewhat easy for me in this subject. I am pretty sure
if you study this modules you will forget 90% during the exam. So understand this
subject, and learn the subject as it is with curiosity. Every module is interconnected
and interesting. Best of luck
😉
T Allwin Kingstan
tallwinkingstan@gmail.com
Definition
Types of Robots
Degree of Freedom
Manipulators
Robot Anatomy
Link
Joint
Manipulator
Wrist
End-effectors
Actuators
Sensors
Controller
Robot Configuration
Articulated Configuration (RRR)
Spherical Configuration (RRP)
SCARA (RRP)
Cylindrical Configuration (RPP)
Cartesian Configuration (PPP)
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Mobile Robots
Keys issues of Locomotion
Legged Mobile Robots
Leg configuration and Stability
Wheeled Robots
Four basic wheel types
Areal Robots
Underwater Robots
Surface water Robots
Dynamic Characteristics of Robot
Speed of Motion
Load Carrying Capacity
Speed of Response
Repeatability
Control Resolution
Spatial Resolution
Mechanical Errors
Accuracy
Stability
End-Effectors
Grippers
Classification of Grippers
Mechanical Grippers
Magnetics Grippers
Pneumatic or Vacuum Grippers
Adhesive Grippers
Special tools
Hooks
Scoops
Other Miscellaneous Devices
Active and Passive Grippers
Active Grippers
Passive Grippers
Application of Robots
Industrial Applications:
State-of-the-Art Applications
Ethics in Robotics
The Three Laws of Robotics
Implications and Applications of Three Laws
Definition
The term “robot” was derived from the English translation of fantasy play written in Czechoslovakia
around 1920.
A Robot carries out the task done by a human being. A robot may do assembly work where some
sort of intelligence or decision making capability is expected.
Robotics is the science of designing and building robots suitable for real life application in
automated manufacturing non-manufacturing environment.
Types of Robots
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Manipulators (Robotics Arms)
Mobile Robots
Arial Robots
Wheeled Robots’
Legged Robots
Underwater Robots
Surface-water Robots
Degree of Freedom
Degree of Freedom (DOF) refers to the number of independent way a rigid body can move relative
to a fixed reference point.
Imagine a point on a gird - it can only move up/down and right/left, for a total of 2 degree of
freedom.
⚠️ Model Question
What do you mean by degrees of freedom? How many degrees of freedom are
required for a drone to achieve any position in 3D space? And how many more
DOF required for achieving any orientation as well.
For a drone to achieve any position in 3D space, it require 3 degree of freedom:
X-axis translation : This allow to move left or right
Y-axis translation: forward or backward
Z-axis translation: up or down
To achieve any orientation, the drone will require 3 more degree of freedom:
Roll: This allows the drone to rotate along x-axis, tilting it left or right.
Pitch: This allows the drone to rotate along y-axis, titling it up or down.
Yaw: This allows the drone to rotate along its z-axis, spinning it clockwise or
counterclockwise.
There for total degree of motion we need 6 degrees of motion.
Manipulators
A robotic arm is a type of mechanical arm, usually programmable, with similar functions to a human
arm; the arm may be the sum total of the mechanism or may be part of a more complex robot. The
links of such a manipulator are connected by joints allowing either rotational motion (such as in an
articulated robot) or translational (linear) displacement. The links of the manipulator can be
considered to form a kinematic chain. The terminus of the kinematic chain of the manipulator is
called the end effector and it is analogous to the human hand.
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Robot Anatomy
A robot as a system consists of a manipulator or rover, a wrist, an end-effector, actuators, sensors,
controllers, processors and software.
Link
A robot arm or robot link is a rigid member that may have relative motion with respect to other links.
Joint
Two links are connected using joints where their relative motion can take place.
There are mainly two types of joints:
1. Revolute (rotary): is like a hinge and allows relative rotation between links.
2. Prismatic (translatory): allows a translation of relative motion between link
Relative rotation & relative translation of connected links occurs about a line called axis of joint.
There are also two more types of joints:
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Active joints: The coordinating of the active joints are controlled by an actuators. Active joints
are usually prismatic or revolute.
Passive joints: has no actuators. Passive joints are also called inactive or free joints.
Manipulator
The main body of a robot which consisting of the links, joints and other structural elements is know
as the manipulator.
A manipulator becomes a robot when wrist and grippers are attached.
Wrist
The joints in between the forearm and end-effector are referred to as the wrist.
We may design a wrist having one, two ore three DOF depending on the application.
End-effectors
The end-effector is the part mounted on the last link to do the required job of the robot. The
simplest end-effector is a gripper, which is usually capable of only two actions: opening and
closing.
The wrist and end-effector assembly is called a hand.
Actuators
Actuators are drivers that move the joints in robots to change their configuration.
The actuators provide the mechanical power to act against gravity, inertia and other external force.
The actuators can be electric, hydraulic or pneumatic type and have to be controlled.
Sensors
The sensors are elements used in robots for detecting and collecting information about the internal
condition of robot and its surrounding environment.
Controller
The controller or control unit of the robot include processor and software. It has three roles.
1. Information roles which consists of collecting and processing the information provided by the
sensor of the robot.
2. Decision roles, which consists of planning the geometric motion of the robot structure.
3. Communication roles, which consists of organizing the information between the robot and its
environment.
Robot Configuration
Most industrial manipulators at the present have six or fewer DOF. These manipulators are usually
classified kinematically on the basis of first three points of the arms, with the wrist being described
separately.
Articulated Configuration (RRR)
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The articulated configuration is also called revolute or anthropomorphic manipulator.
The revolute configuration provides for relative large freedom of movement in a compact space.
e.g. Motoman SK16
Spherical Configuration (RRP)
It is formed by replacing the third joint in articulated configuration with prismatic joint.
Also the coordinated defined by the three joints is same as the spherical coordinate system.
e.g. Stanford arm
SCARA (RRP)
SCARA (Selective Compliant Articulated Robot for Assembly) is tailored for assembly operation.
Although the SCARA has an RRP structure the difference is that RRP structure has 3 axes x0 , z1 , z2 
​
​
​
mutually perpendicular but SCARA has it parallel.
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e.g. EPSON E2L653S
Cylindrical Configuration (RPP)
The first joint is revolute, which produced the rotation about the base.
While the second and third joints are prismatic.
The coordinated produced by this configuration is cylindrical in shape (hence the name).
e.g. Seiko RT3300
Cartesian Configuration (PPP)
A manipulator whose firs three joints are prismatic is known as a cartesian manipulator. The
coordinates of the three joints are the same as the Cartesian coordination system.
The kinematic description of this manipulator is the simplest of all configuration.
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e.g. EPSON-Seiko
Mobile Robots
A mobile robot need locomotion mechanism that enable it to move unbounded throughout its
environment.
In general, legged locomotion require higher degrees of freedom and therefore greater mechanical
than wheeled locomotion. Wheels, in addition to being simple, are extremely well suited to flat
ground.
Keys issues of Locomotion
Stability
Characteristics of contacts
Types of environment
Legged Mobile Robots
Legged locomotion is characterized by a series of point contacts between the robot and the
ground.
Key advantages include adaptability and maneuverability in rough terrain.
Disadvantage of legged locomotion is power and mechanical complexity. Additionally, high
maneuverability will only be achieved if the legs have a sufficient degree of freedom to impart
forces in a number of different directions.
Leg configuration and Stability
⚠️ Model Question
Explain how leg configuration affects the stability of mobile robot.
A robot with three legs can exhibit static, stable pose provided that it can ensure that its center of
gravity is within the tripod of ground contact.
In order to achieve static walking, a robot must have at least four legs, moving one of it at a time.
For six legs, it is possible to design a gait in which a a statically stable tripod of legs is in contact
with the ground at all times.
Then number of possible gaits depends on the number of legs.
For a mobile robot with k legs, the total number of distinct even sequences N for a walking
machine is:
N = (2k − 1)!
💡
Gait is the sequence of lift and release events for the individual legs.
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In the case of legged mobile robots, a minimum of two degree of freedom is generally required to
more a leg forward by lifting the leg and swinging it forward.
Wheeled Robots
Wheeled robots that navigate around the ground using motorized wheels to propel themselves.
This design is simpler than using treads or legs and by using wheels they are easier to design,
build, and program for movement in flat, not-so-rugged terrain.
They are also more well controlled than other types of robots.
Disadvantages of wheeled robots are that they can not navigate well over obstacles, such as rocky
terrain, sharp declines, or areas with low friction.
Wheeled robots are most popular among the consumer market, their differential steering provides
low cost and simplicity.
Robots can have any number of wheels, but three wheels are sufficient for static and dynamic
balance. Additional wheels can add to balance; however, additional mechanisms will be required to
keep all the wheels in the ground, when the terrain is not flat.
Four basic wheel types
The four basic wheel types. (a) Standard wheel: two degrees of freedom; rotation around the (motorized) wheel axle
and the contact point.(b) castor wheel: two degrees of freedom; rotation around an offset steering joint. (c) Swedish
wheel: three degrees of freedom; rotation around the (motorized) wheel axle, around the rollers, and around the
contact point. (d) Ball or spherical wheel: realization technically difficult.
1. Standard Wheel:
Highly directional with a primary axis of rotation.
Allows for precise steering along a vertical axis without side effects since the center of
rotation passes through the contact patch with the ground.
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Suitable for applications requiring straightforward directional control, such as indoor
navigation, smooth surfaces, or vehicles traveling along predetermined paths.
2. Castor Wheel:
Shares characteristics with the standard wheel in terms of being directional with a primary
axis of rotation.
Differs in that it rotates around an offset axis during steering, which can impart lateral forces
on the robot chassis.
Provides enhanced maneuverability and agility but may introduce instability or drag forces
during movement, especially at higher speeds or on uneven terrain.
3. Swedish Wheel:
Functions akin to a standard wheel but offers reduced resistance in multiple directions,
enabling versatile movement.
Equipped with small passive rollers around its circumference, allowing for minimal friction
movement along various trajectories.
Powered solely along its primary axis, typically through the axle, yet capable of
kinematically moving in various directions with minimal resistance, such as the Swedish 90
or Swedish 45 configurations.
4. Spherical Wheel:
Represents a truly omnidirectional wheel, facilitating movement in any direction without the
need for steering.
Typically designed with active mechanisms to spin along any desired direction, offering
exceptional maneuverability and agility.
Implementation often involves powered rollers resting against the top surface of a sphere,
akin to the mechanism found in computer mice, enabling rotation and movement in any
direction with minimal friction.
⚠️ Model Questions
Explain the general features of wheeled, legged and aerial robots. (9 marks)
You wish to build a dynamically stable robot with a single wheel only. For each of the
four basic wheel types, explain whether or not it may be used for such a robot.
(Course outcome question)
In addition to these types of wheels, it's highlighted that for robots designed for all-terrain
environments or those with more than three wheels, a suspension system is often necessary to
maintain wheel contact with the ground. While some solutions may involve incorporating flexibility
directly into the wheel design, more dynamic suspension systems may be required for significantly
non-flat terrains or applications demanding higher levels of stability and adaptability.
Areal Robots
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Aerial robots, also known as Unmanned Aerial Vehicles (UAVs) or drones, are flying machines that
operate without a human pilot on board. They are a rapidly developing field of robotics with a vast
range of applications.
There are two main types of aerial robots: fixed-wing UAVs that resemble miniature airplanes and
rotary-wing UAVs, the most common type, which are multirotor with multiple rotors for lift and
maneuverability. These are ideal for tasks requiring hovering or precise positioning.
A UAV is just one part of a larger system called an Unmanned Aircraft System (UAS). A typical UAS
includes the UAV itself, a Ground Control Station (GCS) for controlling the UAV, and a
communication link between them.
UAVs can operate with varying degrees of autonomy, from being entirely remote-controlled by a
human pilot to following pre-programmed waypoints or even flying autonomously using onboard
sensors and algorithms.
The applications of aerial robots are numerous and span various sectors. They are used in search
and rescue, aerial photography, infrastructure inspection, agriculture, delivery services, and even
traffic monitoring. Military applications include reconnaissance, surveillance, and combat support.
Underwater Robots
Venturing beneath the waves, underwater robots offer another exciting frontier in robotics. These
submersible machines come in various shapes and sizes, aiding humans in exploring and
understanding the vast underwater world. There are two main categories:
Remotely Operated Vehicles (ROVs): Tethered to a surface vessel by a cable, these robots
receive power, control signals, and transmit data. Piloted by human operators on the ship, ROVs
offer high precision maneuvering for tasks requiring real-time control and human intervention,
such as underwater inspections, maintenance, and scientific research.
Autonomous Underwater Vehicles (AUVs): Unlike ROVs, AUVs operate on their own without a
physical tether. Pre-programmed with a mission plan, they navigate using onboard sensors,
GPS, and sophisticated algorithms. AUVs excel at autonomously collecting data over large
areas, performing repetitive tasks, and exploring dangerous or remote environments. They are
used for oceanographic research, mapping the seabed, and underwater exploration.
Surface water Robots
The robotic realm extends beyond the depths. Surface water robots navigate the interface between
water and air, providing unique capabilities. These robots can be further categorized:
Autonomous Surface Vehicles (ASVs): Similar to AUVs, ASVs are self-propelled robots that
operate on the water's surface without a human crew. They are used for various tasks,
including hydrographic surveying, water quality monitoring, and search and rescue operations
in open water.
Unmanned Surface Vessels (USVs): These robots can be remotely controlled or operate with
varying degrees of autonomy. USVs find applications in coastal security patrols, environmental
monitoring, and defense applications.
Together, aerial robots, underwater robots, and surface water robots play a vital role in various
fields. They extend human reach, allowing us to explore challenging environments, gather vital
data, and perform tasks that would be difficult or dangerous for humans to undertake directly.
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Aspect
Wheel-Based Robots
Legged Robots
Aerial Robots
Terrain
Flat and even surfaces
Diverse terrains
including rough,
uneven, or obstaclefilled environments
Not constrained by
terrain; can access
remote or hard-toreach areas
Mobility
Efficient on smooth
surfaces; generally
faster
Superior mobility in
complex terrains
Rapid coverage of
large areas; aerial
navigation
Adaptability
Limited adaptability to
uneven or rough
terrains
Can adapt to changing
environments and
overcome obstacles
Not constrained by
terrain obstacles;
versatile in aerial
navigation
Control Complexity
Relatively simple
mechanics; easier to
control
Requires sophisticated
control algorithms due
to complexity of legged
locomotion
Requires stabilization
and maneuvering
algorithms for flight
Energy Efficiency
Generally more energyefficient on appropriate
surfaces
May have higher
energy consumption
due to complexity of
legged locomotion
Limited by flight
endurance and battery
capacity
Maintenance
Easier to maintain due
to simpler mechanics
May require more
maintenance due to
complexity of
mechanical systems
Maintenance
requirements depend
on drone complexity
and usage
Applications
Suitable for indoor
floors, roads, and flat
outdoor areas
Ideal for forests,
disaster sites, rocky
terrain, and rough
environments
Valuable for aerial
surveillance,
photography,
agriculture, search and
rescue, etc.
Limitations
Struggles with uneven
or rough terrains and
obstacles
Limited payload
capacity and
endurance compared
to ground-based
counterparts
Susceptible to weather
conditions, airspace
regulations, and battery
limitations
Dynamic Characteristics of Robot
Speed of Motion
This characteristic shows how fast a robot can move from one place to another. It depends on how
the robot is made, what makes it move (like wheels or legs), and the environment it's in. The speed
can change depending on things like the ground it's moving on, stuff in its way, and what it needs
to do. It's super important for jobs where the robot needs to move quickly, like delivering things fast
or responding to emergencies.
Load Carrying Capacity
The load carrying capacity denotes the maximum weight a robot can handle while maintaining
stability and operational efficacy. This attribute is influenced by factors including structural
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robustness, actuation mechanisms, and balance. Load capacity is pivotal for tasks involving
material handling, transportation, and payload delivery, varying significantly based on the robot's
size and construction.
Speed of Response
Reflecting how promptly a robot can react to changes in its environment or user inputs, the speed
of response encompasses elements like acceleration, deceleration, and agility. It plays a vital role
in tasks requiring dynamic movement, obstacle avoidance, and interaction with the environment.
Factors impacting response time encompass distance to be traversed, object weight, and accuracy
requirements.
Repeatability
Repeatability measures a robot's ability to position an object precisely at a previously taught point
within its work envelope. This characteristic is critical for tasks necessitating accurate positioning
and assembly. It is influenced by factors such as control resolution, mechanical errors, and the
precision of the robot's motion.
Control Resolution
Control resolution pertains to the system's capability to divide the range of total movement into
closely spaced points. This attribute determines the minimum noticeable movement achievable by
the robot and is affected by the precision of the control system and the resolution of feedback
sensors.
Spatial Resolution
Spatial resolution amalgamates the control resolution of all motions and considers mechanical
errors in the points and associated links. It provides an overall measure of the robot's positional
accuracy and is influenced by factors including control resolution, mechanical errors, and the
accuracy of the robot's motion.
Mechanical Errors
Mechanical errors stem from various sources such as backlash in gears, hysteresis, deflection of
links, or hydraulic leaks. These errors impact the robot's accuracy, repeatability, and spatial
resolution and can be mitigated through proper maintenance, calibration, and design
considerations.
Accuracy
Accuracy signifies the robot's ability to position the end of its wrist precisely at the desired location
within its work envelope. This characteristic is crucial for tasks requiring precise manipulation and
placement of objects and is influenced by control resolution, mechanical errors, and the stability of
the robot's motion.
Stability
Stability denotes the amount of overshoot and oscillations in the robot's motion as it approaches a
designated location. It profoundly affects the robot's performance and safety, especially during
high-speed or dynamic movements. Enhanced stability can be achieved through robust control
algorithms, feedback systems, and meticulous mechanical design.
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⚠️ Model Questions
Briefly explain the dynamic characteristics of robots. (9 marks)
End-Effectors
Definition: An end-effector is a device attached to the wrist of a robot arm, enabling it to
perform specific tasks.
Purpose: Most production machines require specialized fixtures and tools designed for
particular operations, and robots are no exception. The end-effector serves as part of the
special-purpose tooling for a robot.
Design: Robot manufacturers often have dedicated engineering groups to design end-effectors.
Also Known As: End-effectors are commonly referred to as grippers, and there are various
types designed to perform different work functions.
Features: End-effectors can be designed with multiple fingers, joints, and degrees of freedom
to suit various tasks.
Grippers
Definition: Grippers are end-effectors used for grasping and holding objects, such as work
parts to be moved by the robot.
Applications: Grippers are commonly used in part-handling tasks, including machine loading
and unloading, picking parts from conveyors, and arranging parts into pallets.
Specialized Tasks: Grippers can also hold tools like welding guns, spray painting guns, or
deburring tools, and may include specialized devices like Remote Centre Compliance (RCC) for
specific insertion tasks.
Classification of Grippers
1. Mechanical Grippers: Utilize mechanical mechanisms for grasping and holding objects.
2. Magnetic Grippers: Employ magnetic forces to grasp ferrous objects.
3. Pneumatic or Vacuum Grippers: Utilize pneumatic or vacuum systems to create suction for
grasping objects.
4. Adhesive Grippers: Use adhesive materials to adhere to and hold objects.
5. Special tools: Include various other types of grippers designed for specific applications.
Mechanical Grippers
Definition: A mechanical gripper is an end-effector designed to grasp objects using mechanical
fingers actuated by a mechanism.
Operation: The fingers of the gripper make direct contact with the object to secure it firmly.
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Integration: The fingers may be either attached to the mechanism or be an integral part of it,
depending on the design and functionality requirements.
Interchangeability: Applications often utilize interchangeable mechanisms, allowing for wear
and tear. Different sets of fingers can be designed for use with the same gripper mechanism,
accommodating various types or sizes of objects.
Key Features and Functions:
1. Mechanical Finger Design: The fingers of a mechanical gripper are typically designed to
provide a secure grip on objects. They may have specialized surfaces or textures to enhance
friction and grip strength.
2. Actuation Mechanism: The mechanism responsible for opening and closing the gripper fingers
can vary in complexity. It may utilize pneumatic, hydraulic, or electric actuators, depending on
the application requirements.
3. Contact with Objects: Unlike some other types of grippers, mechanical grippers directly make
contact with the object being grasped. This direct contact ensures a strong and reliable grip,
particularly suitable for handling sturdy or irregularly shaped objects.
4. Interchangeable Fingers: The ability to swap out different sets of fingers allows for versatility in
gripping various objects. This adaptability is beneficial in applications where the gripper needs
to handle a range of part sizes or shapes without requiring a complete gripper replacement.
5. Wear and Tear Considerations: Mechanical grippers may experience wear over time due to
repeated use. Utilizing interchangeable fingers and mechanisms can help mitigate this issue by
allowing worn components to be easily replaced or serviced.
Advantages:
1. Strong and Secure Grip: Mechanical grippers provide a robust and reliable grip on objects,
making them suitable for handling sturdy or irregularly shaped items.
2. Direct Contact: Unlike some other types of grippers, mechanical grippers make direct contact
with the object being grasped, ensuring a secure hold without slippage.
3. Versatility: Interchangeable fingers and mechanisms allow for versatility in handling various
types and sizes of objects, offering flexibility in application.
4. Customization: The design of mechanical grippers can be customized to meet specific
application requirements, including grip strength, finger size, and material compatibility.
5. Ease of Maintenance: Components of mechanical grippers, such as fingers and mechanisms,
can be easily replaced or serviced as needed, minimizing downtime and maintenance costs.
Disadvantages:
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1. Limited Dexterity: Compared to grippers with more complex designs, mechanical grippers may
have limited dexterity and adaptability, especially when handling delicate or complex objects.
2. Potential for Damage: Depending on the gripping force and surface texture of the fingers,
mechanical grippers may exert excessive pressure on delicate objects, leading to damage or
deformation.
3. Less Efficient for Certain Shapes: Mechanical grippers may struggle to grasp objects with
irregular shapes or complex geometries, requiring additional customization or specialized
tooling.
4. Limited Range of Motion: The range of motion of mechanical grippers may be restricted
compared to other types of grippers, limiting their suitability for tasks requiring intricate
manipulation or multi-axis movement.
5. Complexity of Design: Designing and optimizing mechanical grippers for specific applications
may require expertise in mechanical engineering, leading to potentially higher development
costs and longer lead times.
Applications and Considerations:
Manufacturing and Assembly: Mechanical grippers are commonly used in manufacturing and
assembly processes for tasks such as picking and placing parts, loading and unloading
machines, and assembling components.
Industrial Automation: In industrial automation settings, mechanical grippers play a crucial role
in automating repetitive tasks, improving efficiency, and reducing labor costs.
Material Handling: These grippers are suitable for handling a wide range of materials, including
metal components, plastic parts, and packaged goods.
Customization: The design of mechanical grippers can be customized to meet specific
application requirements, including the type of object being handled, the desired grip strength,
and environmental conditions.
Magnetics Grippers
Usage: Magnetic grippers are primarily utilized for handling ferrous materials due to their
magnetic properties.
Challenges: Residual magnetism in the workpiece can pose challenges, potentially causing
problems such as unintended attraction or lifting of multiple sheets.
Advantages:
1. Variability in Part Size: Magnetic grippers can tolerate variations in part size, making them
versatile for handling objects of different dimensions.
2. Fast Pickup Times: These grippers offer rapid pickup times, contributing to increased
efficiency in material handling processes.
3. Handling of Metal Parts with Holes: Magnetic grippers have the capability to handle metal
parts with holes, enhancing their applicability in various industrial scenarios.
4. Single Surface Grip: Only one surface is required for gripping, simplifying the setup process
and reducing the complexity of handling operations.
Disadvantages:
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1. Difficulty in Single Sheet Pickup: It can be challenging to pick up a single sheet at a time from
a stack due to the magnetic attraction extending beyond the top sheet.
2. Potential for Workpiece Characteristics Alteration: There's a risk of changes in the
characteristics of the workpiece due to magnetic interaction, which may affect its properties or
integrity.
Types of Magnetic Grippers:
Electromagnetic Grippers: These grippers utilize an electromagnetic field to generate magnetic
attraction, offering controllability and flexibility in operation.
Permanent Magnet Grippers: Permanent magnet grippers feature fixed magnets that provide
consistent magnetic force without the need for external power, offering simplicity and reliability
in gripping operations.
Pneumatic or Vacuum Grippers
Overview: Pneumatic or vacuum grippers, often referred to as suction cups, are utilized for
handling specific types of objects, particularly those with flat, smooth, and clean surfaces.
Object Handling: Vacuum grippers are designed to handle objects that meet certain criteria,
such as being flat, smooth, and free of debris, to ensure a satisfactory vacuum seal between
the object and the suction cup.
Material Composition: The suction cup of a vacuum gripper is typically made of elastic
materials like rubber or soft plastic, allowing for flexibility and adaptability to different surface
contours.
Vacuum Creation Mechanism: In vacuum gripper design, methods for removing air between
the suction cup and the object surface are employed to create a vacuum. Common devices
used for this purpose include vacuum pumps and venturi systems.
Vacuum Pump: Vacuum pumps are piston-operated devices powered by electric motors. They
are capable of creating relatively high vacuum levels, ensuring strong suction force for secure
object gripping.
Venturi System: Venturi systems operate using shop air pressure. They offer a cost-effective
alternative to vacuum pumps and are relatively reliable due to their simplicity in design and
operation.
Advantages:
1. Versatile Handling: Vacuum grippers are suitable for a wide range of applications involving flat,
smooth objects, offering versatility in handling various materials and shapes.
2. Ease of Use: Suction cups are straightforward to install and operate, requiring minimal setup
and maintenance compared to more complex gripper systems.
3. Gentle Handling: Vacuum grippers provide gentle handling of delicate objects, minimizing the
risk of damage during gripping and release.
4. Cost-Effectiveness: Venturi systems offer a cost-effective solution for creating vacuum
pressure, making them an economical choice for certain applications.
Disadvantages:
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1. Limited Compatibility: Vacuum grippers are only suitable for objects with flat, smooth surfaces,
limiting their applicability in handling irregular or textured objects.
2. Dependency on Surface Condition: The effectiveness of vacuum grippers relies heavily on the
cleanliness and condition of the object surface, requiring meticulous surface preparation for
optimal grip performance.
3. Vacuum Loss: Vacuum grippers may experience vacuum loss over time due to factors such as
leaks or insufficient seal integrity, potentially affecting grip stability and reliability.
4. Limited Grip Force: Compared to other gripper types, vacuum grippers may have limited grip
force capabilities, particularly for heavy or bulky objects requiring strong holding force.
Adhesive Grippers
Introduction: Adhesive grippers utilize an adhesive substance for grasping objects, offering an
alternative gripping solution for specific applications.
Handling Capability: These grippers are suitable for handling fabrics and other lightweight
materials, providing a secure grip without damaging the object's surface.
Single-Sided Gripping: Adhesive grippers are designed to grip objects on one side only,
making them ideal for scenarios where other forms of grasping, such as vacuum or magnetic
gripping, are not suitable or feasible.
Limitations:
Reliability: One of the main limitations of adhesive grippers is the loss of reliability with each
successive operation. Over time, the adhesive material may lose its effectiveness, leading to
reduced grip strength and potential dropping of the object.
Mitigation Strategies:
Continuous Ribbon Feeding Mechanism: To overcome the limitation of reliability loss, adhesive
materials can be loaded in the form of a continuous ribbon in a feeding mechanism. This
ensures a constant supply of fresh adhesive material, maintaining grip strength and reliability
during multiple operations.
Advantages:
1. Gentle Handling: Adhesive grippers provide gentle handling of delicate materials, minimizing
the risk of damage or distortion during gripping and release.
2. Versatility: These grippers offer versatility in handling a wide range of lightweight materials,
including fabrics, films, and foils, making them suitable for various industrial applications.
3. Single-Sided Gripping: The ability to grip objects on one side only allows for unique handling
capabilities, particularly useful for scenarios where other gripping methods are not viable.
4. Compact Design: Adhesive grippers typically feature a compact and lightweight design,
making them suitable for integration into robotic systems with limited space or payload
capacity.
Disadvantages:
1. Reliability Loss: The main disadvantage of adhesive grippers is the loss of reliability over time,
as the adhesive material may degrade with repeated use, requiring frequent maintenance or
replacement.
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Applications:
Packaging and Assembly: Adhesive grippers are commonly used in packaging and assembly
operations for handling lightweight materials such as films, foils, and paper.
Textile Industry: These grippers find applications in the textile industry for handling fabrics and
garments during production and handling processes.
Electronics Assembly: Adhesive grippers are used in electronics assembly for picking and
placing small components onto circuit boards or assemblies.
Special tools
Hooks
Hooks serve as end effectors for handling containers and loading or unloading parts suspended
from overhead conveyors.
Objects handled by hooks must have a suitable handle or attachment point for gripping.
Scoops
Ladles and scoops are employed to handle materials in liquid or powder form.
Ladles and scoops facilitate the transfer of materials from one location to another, particularly
in manufacturing or processing environments.
Limitations:
Control of Material Amount: One limitation of scoops is the difficulty in controlling the amount
of material being scooped by the robot. This can lead to inconsistencies in handling tasks,
particularly with powders or granular materials.
Other Miscellaneous Devices
Apart from hooks and scoops, other types of grippers include inflatable devices, where
inflatable bladders are expanded to grasp objects.
These inflatable bladders are fabricated from elastic materials like rubber, making them suitable
for gripping fragile objects without causing damage.
Advantages and Applications:
Versatility: Hooks, scoops, and inflatable devices offer versatility in handling various types of
objects, from containers to powders and fragile items.
Specialized Applications: These devices are often used in specialized applications where
conventional grippers may not be suitable, such as handling objects with irregular shapes or
delicate surfaces.
Efficiency: Hooks and scoops streamline material handling processes, improving efficiency and
reducing the need for manual intervention in tasks like loading and unloading.
Considerations:
Compatibility: The design and selection of hooks, scoops, and inflatable devices should
consider the compatibility with the objects being handled, ensuring a secure grip without
causing damage.
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Control: For scoops, maintaining control over the amount of material being transferred is crucial
to prevent spillage or wastage.
Maintenance: Regular maintenance and inspection of these devices are essential to ensure
optimal performance and safety in industrial environments.
Active and Passive Grippers
Active Grippers
Definition: Active grippers are end-effectors that use powered mechanisms to grasp and
manipulate objects.
Operation: These grippers typically utilize motors, pneumatics, hydraulics, or other actuators to
actively control the gripping action.
Features: Active grippers offer precise control over gripping force, speed, and position,
allowing for versatile handling of a wide range of objects.
Applications: They are commonly used in industrial automation, robotics, and manufacturing
processes where precise and dynamic object manipulation is required.
Advantages: Active grippers provide flexibility, adaptability, and efficient handling of objects,
enhancing productivity and reducing manual labor.
Passive Grippers
Definition: Passive grippers are end-effectors that do not require external power sources for
operation.
Operation: These grippers rely on mechanical or material properties, such as springs, elasticity,
or adhesion, to grasp and hold objects.
Features: Passive grippers are typically simpler in design and operation compared to active
grippers, offering reliability and ease of use.
Applications: They are suitable for tasks where power sources are limited or where simplicity
and robustness are prioritized over dynamic control.
Advantages: Passive grippers are cost-effective, low-maintenance, and suitable for handling a
wide range of objects without the need for complex control systems.
Comparison:
Control: Active grippers offer precise control over gripping parameters, while passive grippers
rely on mechanical properties for gripping without active control.
Complexity: Active grippers are often more complex in design and operation compared to
passive grippers, which are typically simpler and more robust.
Applications: Active grippers are preferred for tasks requiring dynamic and precise
manipulation, while passive grippers excel in applications where simplicity and reliability are
paramount.
Considerations:
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Task Requirements: The choice between active and passive grippers depends on the specific
requirements of the task, including object characteristics, handling speed, precision, and
environmental conditions.
Cost: Active grippers may incur higher initial costs due to their complexity and power
requirements, while passive grippers offer cost-effective solutions with lower maintenance
requirements.
Integration: Both types of grippers can be integrated into robotic systems, with active grippers
requiring additional control interfaces and power sources.
Application of Robots
A robot is a versatile, reprogrammable machine designed to manipulate materials, parts, tools,
or specialized devices through programmed motions for various tasks.
Industrial robots, comprising 90% of all robots used, are primarily found in factories, though
they are also being deployed in warehouses, laboratories, research facilities, power plants,
hospitals, undersea environments, and outer space.
Key advantages of robots in industrial applications include their ability to work continuously
without the need for rest, their suitability for hazardous tasks, and their capability to perform
repetitive work without boredom.
Industrial Applications:
1. Material Handling:
The transfer of workpieces between stations accounts for a significant portion of
manufacturing time.
Robots are used for loading and unloading machine tools, with applications ranging from
tending a single machine to serving multiple machines.
Various types of robots, from lightweight pneumatic to massive hydraulic manipulators, are
employed based on the weight and nature of the items being handled.
Point-to-point control is essential for material handling applications, necessitating
controllers capable of storing numerous points and facilitating easy programming.
2. Welding:
Welding operations performed by robots involve thermal processes where metals are joined
by melting or fusing their contacting surfaces.
Two main types of welding operations are spot welding and arc welding, each requiring
different equipment and control systems for the robot arm.
3. Spray Painting:
Robots are extensively used in spray painting applications, offering advantages in terms of
efficiency and worker safety.
Spray painting robots feature characteristics such as continuous path capability, high
dexterity, and compact wrists to navigate painting environments effectively.
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Unlike other robot applications, repeatability and resolution requirements are less stringent
in spray painting, where precise end-point location is not critical.
4. Assembling:
Robotic assembly systems provide cost-effective solutions for assembling small products,
such as electrical switches and small motors.
Tactile or optical sensors may be integrated into assembly robots to handle more complex
assembly tasks efficiently.
Some assembly tasks may require multiple robots, and selective compliance-assembly
robot-arm (SCARA) type robots are often used for vertical assembly motions.
5. Machining:
While robots are primarily used for drilling operations in machining, they are also employed
for deburring metal parts.
Deburring involves the removal of burrs, rough edges, or ridges left on machined surfaces,
which can be efficiently performed by robots.
State-of-the-Art Applications
1. Medical:
Surgical robots serve as versatile tools that extend surgeons' capabilities, offering benefits
such as reduced casualty rates and shortened operative times.
Surgical assistant robots, controlled directly by surgeons, augment the surgeon's ability to
manipulate surgical instruments during procedures.
These systems must be compatible with operating theatre requirements, providing
sufficient strength, accuracy, and dexterity while allowing access by clinical staff.
2. Mining:
Robots are used in mining operations to enhance productivity, access unworkable mineral
seams, and reduce human exposure to hazardous environments.
Laser range scanners are employed to model the environment and compute the robot's
position accurately in highly constrained mining environments.
3. Space:
Robotic systems play essential roles in space exploration, including space manipulation,
surface mobility for planetary exploration, and robotic colonies for scientific experiments.
Robots used in space missions must exhibit compactness, lightness, robustness, versatility,
and adaptability to succeed in challenging environments.
4. Underwater:
Underwater robots are employed for prospecting minerals, salvaging sunken vessels, and
repairing ships.
These robots exhibit versatile mobility, utilizing vacuum and magnetic feet for gripping
ships' sides and performing scrubbing actions with rotating brushes.
5. Defense:
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Defense applications of robots include mobile fire fighters equipped with infrared sensors
for emergency response.
Other applications include surveillance, mine sweeping, and artillery-loading devices,
enhancing defense capabilities in hazardous environments.
Ethics in Robotics
Ethical considerations are paramount in the development and deployment of robotics technology.
To address ethical concerns and ensure the responsible use of robots, Isaac Asimov proposed the
"Three Laws of Robotics" in his science fiction works. These laws serve as a framework for guiding
the behavior of intelligent machines and protecting human interests.
The Three Laws of Robotics
1. First Law:
"A robot may not injure a human being, or through inaction, allow a human
being to come to harm."
This law emphasizes the primacy of human safety and well-being above all else.
It mandates that robots prioritize the protection of human life and prevent harm to humans
at all costs.
Robots must act to avoid causing physical or psychological harm to humans, whether
directly or indirectly.
This law underscores the ethical imperative of ensuring that robots do not pose threats to
human safety.
2. Second Law:
"A robot must obey the orders given it by human beings, except where
such orders would conflict with the First Law."
The second law emphasizes the importance of obedience and compliance with human
commands.
It establishes human authority over robots and requires robots to follow instructions issued
by humans.
However, this obedience is conditional, as robots must prioritize the First Law's mandate to
prevent harm to humans.
If following human orders would result in harm to humans, robots are obligated to disobey
those orders to uphold the First Law.
3. Third Law:
"A robot must protect its own existence as long as such protection does
not conflict with the First or Second Law."
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The third law addresses self-preservation and the preservation of robotic existence.
While robots are required to prioritize human safety, they are also allowed to protect
themselves from harm.
However, this self-preservation instinct must not supersede the obligations outlined in the
First and Second Laws.
Robots must balance their own survival with the imperative to prevent harm to humans and
obey human commands.
Implications and Applications of Three Laws
The Three Laws of Robotics serve as a foundational ethical framework for guiding the
development and deployment of robotic systems.
They inform the design and programming of robots to ensure that they behave ethically and
responsibly in human environments.
These laws are relevant in various fields, including robotics research, autonomous vehicles,
healthcare robotics, and military robotics.
Compliance with these laws is essential to build trust between humans and robots and foster
the ethical use of robotics technology.
As robotics technology advances, ongoing discussions and revisions may be necessary to
address new ethical challenges and complexities.
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