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TeleRoboticsTeleRoboticsbyby

Amaren P DasAmaren P DasSO-E, DRHR, BARCSO-E, DRHR, BARC

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What is teleroboticsWhat is telerobotics

Use of robots or Active devices to do Use of robots or Active devices to do teleopertionteleopertion

Teleoperation : Ability to manipulate Teleoperation : Ability to manipulate objects remotely.objects remotely.• Poking hot coal in chulhaPoking hot coal in chulha

Telerobotics augments TeleoperationTelerobotics augments Teleoperation

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Teleoperation: Why?Teleoperation: Why?

Which of these things will you like to Which of these things will you like to do with your hand directly.do with your hand directly.

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Tele-roboticsTele-robotics

SetupSetup• Master Side Master Side

Human operator Human operator Controller interface Controller interface

• robot/joystick etcrobot/joystick etc

• Slave SideSlave Side Industrial robotIndustrial robot Remote EnvironmentRemote Environment

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Telerobotics: FeaturesTelerobotics: Features

Separation in space Separation in space • Master and Slave may be separated by Master and Slave may be separated by

large distancelarge distance

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Telerobotics: FeaturesTelerobotics: Features

Difference in Scale Difference in Scale • Works space may be differentWorks space may be different• Actuator capacity differentActuator capacity different

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Telerobotics: FeaturesTelerobotics: Features

Kinematic dissimilarityKinematic dissimilarity• Different dofsDifferent dofs• Different structureDifferent structure

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Tele-robotics augments Tele-robotics augments teleoperationteleoperation

Capability to handle large loads over Capability to handle large loads over large distance –using small master-Less large distance –using small master-Less human fatigue /efforthuman fatigue /effort

Hand tremor reduction for micro Hand tremor reduction for micro manipulation as in micro surgerymanipulation as in micro surgery

Motion guidance to human operator on Motion guidance to human operator on known trajectories, for accurate known trajectories, for accurate assembly.assembly.

Ability to switch between program mode Ability to switch between program mode and teleportation depending on taskand teleportation depending on task

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Why robots need human help!Why robots need human help!

Artificial intelligence and Artificial intelligence and computation power not mature computation power not mature enough to handleenough to handle• If remote environment isIf remote environment is

Unknown / unstructuredUnknown / unstructured Continuously varyingContinuously varying

Programmed robot can’t work ifProgrammed robot can’t work if Task not well definedTask not well defined Non repetitive taskNon repetitive taskTelerobotics is to stay till artificial intelligence supersede human intelligence

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Welcome to the world of Welcome to the world of teleoperationteleoperation

Types of teleoperation Types of teleoperation • Unilateral Unilateral

Slave follows master’s position and/or Slave follows master’s position and/or velocityvelocity

No feedback to the masterNo feedback to the master No actuator on master interfaceNo actuator on master interface Easy to designEasy to design Non intuitive as no force feedbackNon intuitive as no force feedback Using Joystick to control a toy car.Using Joystick to control a toy car.

• BilateralBilateral

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Bilateral teleoperationBilateral teleoperation

Feeling of touch is important in Feeling of touch is important in manipulating thingsmanipulating things• Try assembling a peg in a hole: Don’t we use Try assembling a peg in a hole: Don’t we use

force feedback to align the pegforce feedback to align the peg In bilateral teleoperation In bilateral teleoperation

• Force Fedback to MasterForce Fedback to Master Master-Master- speed/position speed/position slave slave Slave Slave force force Master Master

Adv: Better control over manipulationAdv: Better control over manipulation

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Bilateral teleoperationBilateral teleoperation

Mechanically coupled Master slave Mechanically coupled Master slave systems are inherently bilateralsystems are inherently bilateral

Rugged duty manipulator (RDM): DRHR,Bhabha Atomic Research Center,Mumbai

Disadvantage:

•Uses Principal of Leaver action

•Photo of leave action.

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Current developmentsCurrent developments SlaveSlave

• Industrial Robot KUKA Industrial Robot KUKA (KR-6)(KR-6)

MasterMaster• Omni Phantom (From Omni Phantom (From

Sensable Sensable Techonologies)Techonologies)

• 6-DOF6-DOF• Force reflection on 3 Force reflection on 3

axisaxis• Light and Smaller Light and Smaller

workspaceworkspace• IEEE-1394 Fire-wire IEEE-1394 Fire-wire

interface interface

•Nominal Resolution Nominal Resolution ~0.055~0.055

•Max Exertable force Max Exertable force 3.3N3.3N

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Another DevelopmentAnother Development bilateral teleoperation bilateral teleoperation

Similar configuration robots on both Similar configuration robots on both master and slave sidemaster and slave side

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Development of Laperoscopic Development of Laperoscopic camera manipulation camera manipulation

Unilateral Unilateral operationoperation

BenefitBenefit• Tremor reductionTremor reduction• No drift No drift • Control with the Control with the

main surgeonmain surgeon

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Overview of Kuka-Omni interface Overview of Kuka-Omni interface for bilateral teleoperation for bilateral teleoperation

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Description of Kuka Description of Kuka ManipulatorManipulator

• 6dof manipulator6dof manipulator• Max speed of 2m/s with rated load Max speed of 2m/s with rated load • Repeatability of 20micronsRepeatability of 20microns• Actuators 6AC servo motors from Actuators 6AC servo motors from

SiemensSiemens• Incremental Encoder on each AxisIncremental Encoder on each Axis

EndeffectorEndeffector• Parallel jaw gripperParallel jaw gripper• Pneumatically actuatedPneumatically actuated

TeachPendent TeachPendent (KukaControlPannel)(KukaControlPannel)• Programming InterfaceProgramming Interface

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Safety aspectsSafety aspects• Emergency switch on Teach-pendent (Local) Emergency switch on Teach-pendent (Local)

and access door (External)and access door (External)• Dead-man’s/ Enable switch on teach-pendentDead-man’s/ Enable switch on teach-pendent• 3-Types of braking3-Types of braking

Ramp-Down-stop key pressed, Enable releasedRamp-Down-stop key pressed, Enable released Path-oriented braking-emergency switch pressPath-oriented braking-emergency switch press Short-circuit braking- Encoder fault/Power Short-circuit braking- Encoder fault/Power

failure/power offfailure/power off• Reduced speed teach mode (Total 4 modes)Reduced speed teach mode (Total 4 modes)

Program testingProgram testing• Mechanical and S/w Limit switchesMechanical and S/w Limit switches• Controller has battery back up for save close Controller has battery back up for save close

downdown

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Introduction of kuka robots CSIntroduction of kuka robots CS

Coordinate systemsCoordinate systems• User definedUser defined

Tool Tool BaseBase WorldWorld

• pre-definedpre-defined Robot-RootRobot-Root Tool[0]Tool[0] Base[0]Base[0]

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ProgrammingProgramming

ProgrammingProgramming• Sequential flowSequential flow• No multi threadingNo multi threading• LoopsLoops• SubprogramsSubprograms

Motion programmingMotion programming• PTPPTP• LINLIN• CircCirc• Spline ?Spline ?

Absolute and relative Absolute and relative

Interrupt Interrupt programmingprogramming• Actuates on external Actuates on external

InputsInputs• Can stop robot Can stop robot

prgramaticaly mid way prgramaticaly mid way of its pathof its path

• Modify path after Modify path after stopping the robotstopping the robot

Note: Each motion command is completed before any other motion command is loaded.

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Eyes and Ears of KukaEyes and Ears of Kuka I/O are implemented on Controller PC using field bus cardsI/O are implemented on Controller PC using field bus cards Digital IODigital IO

• 4096 digital Inputs4096 digital Inputs• 4096 digital Outputs4096 digital Outputs

Analog I/OAnalog I/O• 32 Analog inputs and 32 Analog outputs32 Analog inputs and 32 Analog outputs• Range -10V to +10V Range -10V to +10V -1.0 to +1.0 -1.0 to +1.0

EthernetEthernet• OPC Server (non real time)OPC Server (non real time)• Robot Sensor Interface or RSI (real time ,12ms cycle time) Robot Sensor Interface or RSI (real time ,12ms cycle time)

Serial portSerial port• Non real timeNon real time• BlockingBlocking

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The controller KRCThe controller KRC Consists of Consists of

• Standard Pentium PCStandard Pentium PC• Motor driversMotor drivers• Multifunctional cardMultifunctional card• IO device net or any field bus cardIO device net or any field bus card• Power supply Power supply

PC runs VxWorks and Windows Simataniously on PC runs VxWorks and Windows Simataniously on the same processorthe same processor• Kuka scheduler keeps between the 2 OSKuka scheduler keeps between the 2 OS• VxWorks: Runs Control Algos & motor Driver VxWorks: Runs Control Algos & motor Driver

communicationcommunication• Windows is used for user interface for KCPWindows is used for user interface for KCP• VxWorks and Windows communicate using Virtual VxWorks and Windows communicate using Virtual

Network Network

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Bilateral Teleoperation architectureBilateral Teleoperation architecture

Force Torque sensor

Host PC

Omni

Force

position

FF

X

Kuka ArmKuka Controller

Note: Force torque sensor measures the Environmental interaction force/Toruques. It is mounted on the tool / Flang of the robot.

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Desired performance for bilateral-Desired performance for bilateral-teleoperationteleoperation

TransparencyTransparency• Operator should not feel there is any thing Operator should not feel there is any thing

between him and the (remote) Environment.between him and the (remote) Environment.• The tele-operation system should be The tele-operation system should be

transparent non existent to himtransparent non existent to him Stability of the systemStability of the system

• For any meaningful manipulation the slave For any meaningful manipulation the slave should be stable and accurateshould be stable and accurate

• Since master has actuators to reflect force, its Since master has actuators to reflect force, its stability is very important as it may harm the stability is very important as it may harm the operatoroperator

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ChallengesChallenges

Design of natural Interface for the operatorDesign of natural Interface for the operator• Example ExoskeletonExample Exoskeleton

Mapping issues for Kinematical different Mapping issues for Kinematical different master and slavemaster and slave

Time delay due to communication delay or Time delay due to communication delay or computational inefficiency causecomputational inefficiency cause• Lose of Intuitive manipulationLose of Intuitive manipulation• Creates stability related issuesCreates stability related issues

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Thank youThank you