Subject: ROBOTICS ENGINEERING AND APPLICATIONSSubject Code: ME 0002

Department of Mechanical EngineeringYear & Semester : III YEAR I SEMESTERNote : Consider this PPT as reference only

Subject: ROBOTICS ENGINEERING AND APPLICATIONSSubject Code: ME 0002

Department of Mechanical EngineeringYear & Semester : III YEAR I SEMESTERNote : Consider this PPT as reference only

I. INTRODUCTIONBasic concepts of robotics (Laws of Robotics, Robotic system), RIA Definition.History of Robotics, Automation and roboticsRobot anatomy (Robot Configuration, Robot motions, Joint Notation scheme)Robot Manipulators Kinematics.Kinematics: Forward and inverse kinematics, Problems on kinematicsPrecision movement (Spatial resolution, accuracy, repeatability)Robot specifications and Work volume,Types of Robot drives, Electric drives, Hydraulic, Pneumatic drives.Basic robot motions - Point to point control, continuous path control.

2. END EFFECTORSEnd effectors Introduction Classification.Classification

Mechanical Grippers,Magnetic Grippers,Vacuum Grippers andAdhesive Gripper

Gripper force analysis and design.Problems on gripper design and force calculation.Robot control - unit control system concept.Servo and non-servo control of robot jointsAdaptive and optimal control.

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I. INTRODUCTIONBasic concepts of robotics (Laws of Robotics, Robotic system), RIA Definition.History of Robotics, Automation and roboticsRobot anatomy (Robot Configuration, Robot motions, Joint Notation scheme)Robot Manipulators Kinematics.Kinematics: Forward and inverse kinematics, Problems on kinematicsPrecision movement (Spatial resolution, accuracy, repeatability)Robot specifications and Work volume,Types of Robot drives, Electric drives, Hydraulic, Pneumatic drives.Basic robot motions - Point to point control, continuous path control.

2. END EFFECTORSEnd effectors Introduction Classification.Classification

Mechanical Grippers,Magnetic Grippers,Vacuum Grippers andAdhesive Gripper

Gripper force analysis and design.Problems on gripper design and force calculation.Robot control - unit control system concept.Servo and non-servo control of robot jointsAdaptive and optimal control.

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Out line of the end effector1. Introduction of End effectors

a. Grippersb. Tools

2. Mechanical Grippers3. Type of Gripper Mechanism

Linkage actuation Gear and rack actuation Cam actuation Screw actuation Rope and pulley actuation Miscellaneous.

4. Other Grippers1.Vacuum cups( Suction cups)2.Magnetic grippers

a. Electromagnet grippersb. Permanent magnetic grippers

3.Adhesive grippers4.Hooks scoops and other miscellaneous devices

5.Factors to be considered while selecting the end effector6.Difference Grippers and Tools7.Case Study 1: Design and development of Robotic Hand

Out line of the end effector1. Introduction of End effectors

a. Grippersb. Tools

2. Mechanical Grippers3. Type of Gripper Mechanism

Linkage actuation Gear and rack actuation Cam actuation Screw actuation Rope and pulley actuation Miscellaneous.

4. Other Grippers1.Vacuum cups( Suction cups)2.Magnetic grippers

a. Electromagnet grippersb. Permanent magnetic grippers

3.Adhesive grippers4.Hooks scoops and other miscellaneous devices

5.Factors to be considered while selecting the end effector6.Difference Grippers and Tools7.Case Study 1: Design and development of Robotic Hand

An end effector is a device that attached to the wrist of the robot arm and enablesthe general purpose robot to perform a specific task.> It is some times referred as the robots hand.> The end effector is a part of that special purpose tooling for a robot.> It is the gripper or end-of-arm toolingmounted on the wrist.

Usually end effectors must be custom engineered for the particular task which is tobe performed. This can be accomplished either by designing and fabricating the devicefrom scratch or by purchasing a commercially available device and adapting it to theapplication.> Most of robot manufacturers have special engineering groups whose function is todesign end effector and provide consultation services to their customers.> Cost of end-of-arm tooling can account for 20% of the total cost of the robot

Two Functions:1. Hold the part while work is being performed2. Hold tool which is performing work on the part.

Two types of end effectors:1. Grippers To grasp and manipulate objects (e.g., parts) during work cycle2. Tools To perform a process, e.g., spot welding, spray painting

INTRODUCTIONAn end effector is a device that attached to the wrist of the robot arm and enables

the general purpose robot to perform a specific task.> It is some times referred as the robots hand.> The end effector is a part of that special purpose tooling for a robot.> It is the gripper or end-of-arm toolingmounted on the wrist.

Usually end effectors must be custom engineered for the particular task which is tobe performed. This can be accomplished either by designing and fabricating the devicefrom scratch or by purchasing a commercially available device and adapting it to theapplication.> Most of robot manufacturers have special engineering groups whose function is todesign end effector and provide consultation services to their customers.> Cost of end-of-arm tooling can account for 20% of the total cost of the robot

Two Functions:1. Hold the part while work is being performed2. Hold tool which is performing work on the part.

Two types of end effectors:1. Grippers To grasp and manipulate objects (e.g., parts) during work cycle2. Tools To perform a process, e.g., spot welding, spray painting

Shaft

For Small diameters Fitted to the diameter Fitted to the length

Flat

Fig: Robot End effector for different manufacturing applications

Magnet lifter Vacuum Double Gripper Vacuum Gripper

For Large Objects Vacuum gripper for Parts

Box

Contour Surface Box

Vacuum Grippercorrugated surface Vacuum GripperCurved surface Balloon lifter, Bottles

Fig: Robot End effector for different manufacturing applications

Grippers are end effectors used to grasp and hold objects. The objects aregenerally work part that are to moved by the robot.Ex: Part handling applicationsAccording to mechanical grasping grippers can be classified as

1. Single grippers- Only one grasping device is mounted.- Consumes valuable time in production cycle

2. Double grippers+ It has two gripping devices attached to the wrist.+ It is used to handle two separate object.+ These gripping devices actuated independently+ these are subset of multiple grippers.

ex: Machining loading and unloading.According to whether the part is grasped on its exterior surface or its internal surface

1. External surface2. Internal surface

1. Grippers

Grippers are end effectors used to grasp and hold objects. The objects aregenerally work part that are to moved by the robot.Ex: Part handling applicationsAccording to mechanical grasping grippers can be classified as

1. Single grippers- Only one grasping device is mounted.- Consumes valuable time in production cycle

2. Double grippers+ It has two gripping devices attached to the wrist.+ It is used to handle two separate object.+ These gripping devices actuated independently+ these are subset of multiple grippers.

ex: Machining loading and unloading.According to whether the part is grasped on its exterior surface or its internal surface

1. External surface2. Internal surface

Fig: Single grippers

Fig: Double grippers

Multiple end effector (Angular Robot Gripper) Special Purpose Gripper :Palletizing

Fig: Multiple gripper

Fig: Internal & External grippers(a) Internal gripper(b) External gripper

2. ToolsThese are designed to perform work on the part rather than to merely grasp it.

By the definition the tool type end effector is attached to the robots wrist end.ex: Spot welding, Spray painting, etc

The grippers are sometimes used to hold tools rather than work part.The reason for using a gripper instead of attaching the tool directly the robot wrist is typicallybecause the job requires several tools to be manipulated by the robot during the work cycle.

ex: Deburring process

2. ToolsThese are designed to perform work on the part rather than to merely grasp it.

By the definition the tool type end effector is attached to the robots wrist end.ex: Spot welding, Spray painting, etc

The grippers are sometimes used to hold tools rather than work part.The reason for using a gripper instead of attaching the tool directly the robot wrist is typicallybecause the job requires several tools to be manipulated by the robot during the work cycle.

ex: Deburring process

Fig: Tool gripper as a machine cutter

Advantage Robot Tooling Consistency Repeatability No fatigue Shorter cycle time Fewer scrapped parts Fewer injuries

Fig: Robot end effector as tool in Spot welding (automobile) application

Fig: Robot end effector as tool in GMAW welding (automobile, construction) application

Fig: Robot end effector as tool in Spray painting application

Deburring Process:It is usually an unwanted piece of material and when removed with a deburring

tool in a process called 'deburring'.. Burrs are most commonly created after machining operations, such as grinding,

drilling, milling, engraving or turning.

Fig: The tools used in Deburring process

Mechanical grippersA mechanical gripper is an end effector that uses mechanical fingers actuated by a

mechanism to grasp an object.The fingers, some times called jaws, are the appendages of the gripper that actually

make contact with the object.The grippers are either attached to the mechanism or are an integral part of the

mechanism.The fingers are attachable type, then they can be detached and replaced. The use of

replaceable allows wear and interchangeability.The function of the gripper mechanism is to translate same of power input into the

grasping action of the fingers against the part.The power input is supplied from, the robot and can be pneumatic, electric,

mechanical or hydraulic.The mechanism must be able to open and close the fingers and exert sufficient force

against the part when closed to hold it securely.There are two ways of constraining the part in the gripper .

1. By physical constriction of the part with in the fingers.2.Holding the part is by friction between the fingers and the work part.

A mechanical gripper is an end effector that uses mechanical fingers actuated by amechanism to grasp an object.

The fingers, some times called jaws, are the appendages of the gripper that actuallymake contact with the object.

The grippers are either attached to the mechanism or are an integral part of themechanism.

The fingers are attachable type, then they can be detached and replaced. The use ofreplaceable allows wear and interchangeability.

The function of the gripper mechanism is to translate same of power input into thegrasping action of the fingers against the part.

The power input is supplied from, the robot and can be pneumatic, electric,mechanical or hydraulic.

The mechanism must be able to open and close the fingers and exert sufficient forceagainst the part when closed to hold it securely.There are two ways of constraining the part in the gripper .

1. By physical constriction of the part with in the fingers.2.Holding the part is by friction between the fingers and the work part.

2.Holding the part is by friction between the fingers and the work part.With this approach, the fingers must apply a force that is sufficient for friction to

retain the part against gravity, acceleration, and any other force that might rise during theholding portion of the work cycle.

The fingers, or the pads attached to the fingers which makes contact with the part, aregenerally fabricated out of a material that is relatively soft.

This tends to increase the coefficient of friction between the part and the contactfingers surface. It also serves to protect the part surface from scratching or the damage.

The friction method of holding the part results in a less complicated and thereforeless expensive gripper design, and it tends to be reality adaptable to a greater variety of workpart.

How ever there is problem with the friction method that is avoided with the physicalconstriction method.

If a force of sufficient magnitude is applied against the part in a directional parallel tothe friction surfaces of the fingers as a shown in below figure (a) the part might slip out of thegripper.

To resist slippage the gripper must be designed to exert a force that depends on theweight of the part, the coefficient of friction between the part surface and finger surface, theacceleration ( or deacceleration) of the part, and the orientation between the direction of motionduring acceleration and direction of the fingers.

2.Holding the part is by friction between the fingers and the work part.With this approach, the fingers must apply a force that is sufficient for friction to

retain the part against gravity, acceleration, and any other force that might rise during theholding portion of the work cycle.

The fingers, or the pads attached to the fingers which makes contact with the part, aregenerally fabricated out of a material that is relatively soft.

This tends to increase the coefficient of friction between the part and the contactfingers surface. It also serves to protect the part surface from scratching or the damage.

The friction method of holding the part results in a less complicated and thereforeless expensive gripper design, and it tends to be reality adaptable to a greater variety of workpart.

How ever there is problem with the friction method that is avoided with the physicalconstriction method.

If a force of sufficient magnitude is applied against the part in a directional parallel tothe friction surfaces of the fingers as a shown in below figure (a) the part might slip out of thegripper.

To resist slippage the gripper must be designed to exert a force that depends on theweight of the part, the coefficient of friction between the part surface and finger surface, theacceleration ( or deacceleration) of the part, and the orientation between the direction of motionduring acceleration and direction of the fingers.

Fig: Mechanical gripper with interchangeable fingers/ physical constriction of the part

Type of Gripper MechanismThere are various ways of classifying mechanical grippers and their actuating mechanism.The grippers can actuate the opening and closing of the finger by one of the following :1. Pivot movement ( to open and close)

The motion is usually accomplished by some kind of linkage mechanism.2. Linear or translational movement

In the linear movement, the finger open and close by moving in parallel toeach other. This is accomplished by means of guide rails so that each finger base slidesalong a guide rail during actuation.

This movement also accomplished by linkage mechanism.Mechanical grippers can also be according to the type of mechanical device

used to actuate the finger movement. In thins classification we have the following type:1. Linkage actuation2. Gear and rack actuation3. Cam actuation4. Screw actuation5. Rope and pulley actuation6. Miscellaneous.

There are various ways of classifying mechanical grippers and their actuating mechanism.The grippers can actuate the opening and closing of the finger by one of the following :1. Pivot movement ( to open and close)

The motion is usually accomplished by some kind of linkage mechanism.2. Linear or translational movement

In the linear movement, the finger open and close by moving in parallel toeach other. This is accomplished by means of guide rails so that each finger base slidesalong a guide rail during actuation.

This movement also accomplished by linkage mechanism.Mechanical grippers can also be according to the type of mechanical device

used to actuate the finger movement. In thins classification we have the following type:1. Linkage actuation2. Gear and rack actuation3. Cam actuation4. Screw actuation5. Rope and pulley actuation6. Miscellaneous.

Mechanical Finger GrippersLinkage Grippers:

There is no cam, screw, gear.There is movement only because of links attached to input and output.There must be perfect design of mechanism such that input actuators motion is

transformed into the gripping action at the output.

Fig :Linkage Grippers

Gear and Rack Grippers:Movement of input due to gear motion which makes connecting links to go in motion

to make gripping action at the output link.

Fig: Gear and Rack Grippers

Cam-actuated Grippers:Reciprocating motion of the cam imparts motion to the follower, thus causing

fingers to produce a grabbing action.A variety of cam profiles can be employed- constant velocity, circular arcs, harmonic

curves etc.

Fig :Cam-actuated Grippers

Screw-driven Grippers:Operated by turning screw, in turn giving motion to connecting links and thus giving

griping motion to output.Screw motion can be controlled by motor attached.

Screw connected Motor

Fig : Screw-driven Grippers

Rope & Pulley Grippers:Motor attached to the pulley makes the winding and unwinding motion of

rope in turn it set gripper action into motion via connecting link.

Fig : Rope & Pulley Grippers

Pulley

Rope

Soft Grippers:Consists of multi-links and a series of pulleys actuated by a pair of wires.The soft gripper can actively conform to the periphery of objects of any shape and

hold them with uniform pressure.

Multi Links

Fig: Soft Grippers

Three Fingered Grippers:The clamping movement of two-fingered type normally executes

(a)beat movement(b)bite movement(c)parallel movement of the jaw.

They are capable only of grasping or releasing movement.

Fig : Three Fingered Grippers

Other types of grippersIn addition to mechanical gripper there are a variety of other devices that can be

designed to lift and hold objects.Includes among these other types of grippers are the following types.

1.Vacuum cups( Suction cups)2.Magnetic grippers3.Adhesive grippers4.Hooks scoops and other miscellaneous devices

Vacuum cup grippers:For non-ferrous components with flat and smooth surfaces, grippers can be built using

standard vacuum cups or pads made of rubber-like materials.

Initial costs are lowNot suitable for components with curved surfaces or with holes.

Fig: Vacuum Gripper (a) Ventury device for flat surface gripping(b) gripper for contoured surface

The suction cups used in this type of robot grippers are typically made of elasticmaterial such as rubber or soft plastic.

An exception would be when the object to be handled is composed of a softmaterial. In this case, the suction cup would be made of a hard substance.

The vacuum pump is piston operated or vane driven device powered by anelectric motor. It is capable of creating a relatively high vacuum.

The venture is a simpler device as pictured in above fig and it can be driven bymeans of shop air pressure. Its initial cost is less than that of a vacuum pump and itsrelatively reliable because of its simplicity.

However the overall reliability of the vacuum system is dependent on the sourceof air pressure.

The lift capacity of the suction cup depends on the effective area of the cup andthe negative air pressure between the cup and the object.

The relation can be summarized in the following equation.F= PA

Where,F= the force or lift capacity , lbP=the negative pressure , lb/in2A= the total effective area of the suction cup(s) used to create the vacuum.

The suction cups used in this type of robot grippers are typically made of elasticmaterial such as rubber or soft plastic.

An exception would be when the object to be handled is composed of a softmaterial. In this case, the suction cup would be made of a hard substance.

The vacuum pump is piston operated or vane driven device powered by anelectric motor. It is capable of creating a relatively high vacuum.

The venture is a simpler device as pictured in above fig and it can be driven bymeans of shop air pressure. Its initial cost is less than that of a vacuum pump and itsrelatively reliable because of its simplicity.

However the overall reliability of the vacuum system is dependent on the sourceof air pressure.

The lift capacity of the suction cup depends on the effective area of the cup andthe negative air pressure between the cup and the object.

The relation can be summarized in the following equation.F= PA

Where,F= the force or lift capacity , lbP=the negative pressure , lb/in2A= the total effective area of the suction cup(s) used to create the vacuum.

Fig: Vacuum Cups grippers

Fig: Vacuum Cups grippers with material handling applicationFig: Vacuum Cups grippers with material handling application

Fig: Use of Vacuum grippers in packing applications

Magnetic Gripper:Used to grip ferrous materials (sheet or plate form).The S.S would not be an appropriate application for magnetic gripper because 18-8 steel

is not attracted by a magnet.Magnetic gripper uses a magnetic head to attract ferrous materials like steel plates.The magnetic head is simply constructed with a ferromagnetic core and conducting coils.

Fig: Magnetic Gripper with application

Magnetic Gripers can be divided into two categories1. Electromagnet grippers

These are easier to control but requires source of dc power and an appropriatecontroller unit.

As with any other robotic gripping device, the pan must be released at the end of thehandling cycle. This is easier to accomplish with an electromagnet than with a permanentmagnet.

When the part is to be released, the controller unit reverses the polarity at a reducedpower level before switching off the electromagnet. This procedure acts to cancel the residualmagnetism in the workpiece and ensure a positive release of the part.

2. Permanent magnetic grippersThese do not require an external power source to operate the magnet.Stripper device is used to detach the part at the end off cycle.These are often considered for handling tasks in hazardous environments requiringexplosion proof apparatus.

Magnetic Gripers can be divided into two categories1. Electromagnet grippers

These are easier to control but requires source of dc power and an appropriatecontroller unit.

As with any other robotic gripping device, the pan must be released at the end of thehandling cycle. This is easier to accomplish with an electromagnet than with a permanentmagnet.

When the part is to be released, the controller unit reverses the polarity at a reducedpower level before switching off the electromagnet. This procedure acts to cancel the residualmagnetism in the workpiece and ensure a positive release of the part.

2. Permanent magnetic grippersThese do not require an external power source to operate the magnet.Stripper device is used to detach the part at the end off cycle.These are often considered for handling tasks in hazardous environments requiringexplosion proof apparatus.

Continue. Magnetic GrippersAdvantages: Pick up time are very fast Variation in part size can be tolerated. The gripper does not have to be designed for one particular work part. They have the ability to handle metal parts with holes. They require only one of surface for gripping. Decreased air cost Grasps odd or non-uniform parts Outlasts most vacuum parts Wont drop materials during power outage or air loss Low maintenance costDisadvantages

These includes the residual magnetism remaining in the workpiece. Whichmay cause a problem in subsequent handling, possible side slippage and othererrors which limit the precision of this mean of handling.Problem of picking only one sheet from a stack.The magnetic attraction tends to penetrate beyond the top sheet in thestack, resulting the possibility that more than a single sheet will be lifted by themagnet.

Advantages: Pick up time are very fast Variation in part size can be tolerated. The gripper does not have to be designed for one particular work part. They have the ability to handle metal parts with holes. They require only one of surface for gripping. Decreased air cost Grasps odd or non-uniform parts Outlasts most vacuum parts Wont drop materials during power outage or air loss Low maintenance costDisadvantages

These includes the residual magnetism remaining in the workpiece. Whichmay cause a problem in subsequent handling, possible side slippage and othererrors which limit the precision of this mean of handling.Problem of picking only one sheet from a stack.The magnetic attraction tends to penetrate beyond the top sheet in thestack, resulting the possibility that more than a single sheet will be lifted by themagnet.

Adhesive GripperGripper design in which an adhesive substance performs the grasping action can be

used to handle fabrics and other light weight materials.The requirements on the items to be handled are that they must be gripped on one

side only and that other forms of grasping such as a vacuum or magnet are not appropriate.

Miscellaneous GrippersHooks can be used as end effectors to handle containers of parts and to load and

unload parts hanging from overhead conveyor.Scoops and Ladles can be used to handle certain materials in liquid or powder

form ( chemical industries).ex: chemical sin liquid or powder form, food materials, granular

substances, and molten metals etc.Inflatable devices in which an inflatable bladder or diaphragm is expanded to

grasp the object.The inflatable bladder is fabricated out of rubber or other elastic material which

makes it appropriate for gripping fragile objects. The gripper applies a uniform graspingpressure against the surface of the object rather than a concentrated force typical of amechanical gripper.

Inflatable grippers- used for picking up irregular and fragile objects withoutconcentrated loading.

Universal Gripper capable of grasping and handling a variety of objects with differinggeometries.

Miscellaneous GrippersHooks can be used as end effectors to handle containers of parts and to load and

unload parts hanging from overhead conveyor.Scoops and Ladles can be used to handle certain materials in liquid or powder

form ( chemical industries).ex: chemical sin liquid or powder form, food materials, granular

substances, and molten metals etc.Inflatable devices in which an inflatable bladder or diaphragm is expanded to

grasp the object.The inflatable bladder is fabricated out of rubber or other elastic material which

makes it appropriate for gripping fragile objects. The gripper applies a uniform graspingpressure against the surface of the object rather than a concentrated force typical of amechanical gripper.

Inflatable grippers- used for picking up irregular and fragile objects withoutconcentrated loading.

Universal Gripper capable of grasping and handling a variety of objects with differinggeometries.

Scoop gripper Inflatable gripper

Fig: Miscellaneous Grippers

Inflatable gripperFig: Expandable bladder used to grasp inside of a bottle

Quattro robot in Food Packing applications

Factors to be considered while selecting the end effector Application Effector properties

Width of strokeWeightMelting temperatureGripping force

Interfacing with robot Sensors required Quality standards

ISO-14001 Environmental Management System StandardUnderwriters Laboratory (UL)National Electric Manufacturers Association (NEMA)

Frequency of part replacement

Application Effector properties

Width of strokeWeightMelting temperatureGripping force

Interfacing with robot Sensors required Quality standards

ISO-14001 Environmental Management System StandardUnderwriters Laboratory (UL)National Electric Manufacturers Association (NEMA)

Frequency of part replacement

Difference Grippers and Tools

Type of Control SystemRobots may use one of two control systems

1. Non-servo control systems2. Servo control systems

The earliest type of robot was non-servo, which is considered a non-intelligent robot.The second classification is the servo robot.These robots are classified as either intelligent or highlyintelligent.

The primary difference between an intelligent and highly intelligent robot is the level ofawareness of its environment.Non-Servo Robots

Non-servo robots are the simplest robots and are often referred to as limitedsequence, pick-and-place, or fixed-stop robots.The non-servo robot is an open-loop system.In an open-loop system, no feedback mechanism is used to compare programmed positions toactual positions.A good example of an open-loop system is the operating cycle of a washing Machine.

Type of Control SystemRobots may use one of two control systems

1. Non-servo control systems2. Servo control systems

The earliest type of robot was non-servo, which is considered a non-intelligent robot.The second classification is the servo robot.These robots are classified as either intelligent or highlyintelligent.

The primary difference between an intelligent and highly intelligent robot is the level ofawareness of its environment.Non-Servo Robots

Non-servo robots are the simplest robots and are often referred to as limitedsequence, pick-and-place, or fixed-stop robots.The non-servo robot is an open-loop system.In an open-loop system, no feedback mechanism is used to compare programmed positions toactual positions.A good example of an open-loop system is the operating cycle of a washing Machine.

Example:

Fig: Non-servo controlled Robots

Characteristics of non-servo robots: Relatively inexpensive compared to servo robots. Simple to understand and operate. Precise and reliable. Simple to maintain. Capable of fairly high speeds of operation. Small in size. Limited to relatively simple programs.

Servo robotThe servo robot is a closed-loop system because it allows for feedback.In a closed-loop system, the feedback signal sent to the servo amplifier affects the outputof the system.A servo amplifier translates signals from the controller into motor voltage and currentsignals. Servo amplifiers are used in motion control systems where precise control ofposition or velocity is necessary. In a sense, a servomechanism is a type of control systemthat detects and corrects for errors.

Characteristics of servo robots: Relatively expensive to purchase, operate, and maintain. Use a sophisticated, closed-loop controller. Wide range of capabilities. Can transfer objects from one point to another, as well as along acontrolled, continuous path. Respond to very sophisticated programming. Use a manipulator arm that can be programmed to avoid obstructions

Servo robotThe servo robot is a closed-loop system because it allows for feedback.In a closed-loop system, the feedback signal sent to the servo amplifier affects the outputof the system.A servo amplifier translates signals from the controller into motor voltage and currentsignals. Servo amplifiers are used in motion control systems where precise control ofposition or velocity is necessary. In a sense, a servomechanism is a type of control systemthat detects and corrects for errors.

Characteristics of servo robots: Relatively expensive to purchase, operate, and maintain. Use a sophisticated, closed-loop controller. Wide range of capabilities. Can transfer objects from one point to another, as well as along acontrolled, continuous path. Respond to very sophisticated programming. Use a manipulator arm that can be programmed to avoid obstructions

Fig: Servo controlled robots

Case Study 1:Design and development of Robotic End effector (Gripper)

Fig : The gripper dealing with 2 different objects.

Fig: Kinematic structure (a)and mechanical design(b)of Marviss

Fig: First proto type of the new hand.

Fig: Sketch of a robotic finger based on compliantmechanisms(a)and its actual implementation.