RoboticsIntroduction and terminology

Dipartimento di Elettronica, Informazione e Bioingegneria

@ G. Gini 2015

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summary

1. Our course2. Robots: definitions and market3. From robots to robotics4. Robot as a system

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organization

• 50 hours (30 + 20)Wednesday 13:15-15:15 in EG3(lessonclass)

Giuseppina GiniThursday13:15-15:15 in D11(exercise class)

Marcello Restelli

Course site: http://home.deib.polimi.it/gini/robot

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syllabus• 1. THE ROBOT AS A SYSTEM

Functional model of a robot. From robot to robotics.Structural and functional components of a robot (links, joints, actuators, sensors, …). Role of the operator (telecontrolled, programmed, autonomous robot)

• 2. REPRESENTING SPACEHomogeneous transformations and coordinate frames coordinates. Eulerangles.Configuration space vs Cartesian space.

• 3. DESCRIBING MOVEMENT Degrees of mobility and of freedom.Classification and description of mechanical structures (chains, wheels, legs)From Cartesian space to actuation space and back: kinematic models, Denavitt-Hartemberg notation, direct and inverse kinematics of manipulators and wheeled robots.

• 4. SENSING AND PERCEPTIONTypes of sensors and their role as eteroceptive or proprioceptive sensors.triangulation and position estimationImage acquisition and basic image analysis.From computer vision to robot vision.

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syllabus• 5. CONTROLLING THE ROBOT

Actuators for robotics.Robot control based on kinematic model and on trajectory computationNon holonomic constraints and the control of mobile robots.Integration of external sensors (force, vision).

• 6. ROBOT PROGRAMMING Languages in joint and in Cartesiam space.Simulators, virtual reality, and middleware for robotics.The user interface.

• 7. MAPS AND PATH PLANNING Maps and C-space maps.Geometric approaches to path planning and terrain covering.Localization and guidance systems.

• 8. TASK EXECUTIONTelecontrol and semi-autonomous teleoperation .Collision avoidance.Architectures for autonomous robots: reactive, behavior based, deliberative.Robots as physical agents. AI architectures and learning.

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Suggested booksG. Gini, V. Caglioti, "Robotica", Zanichelli 2003 - only in

Italian

J. J. Craig, "Introduction to Robotics: Mechanics and Control", 3nd edition, Addison-Wesley, 2005 - withMatlab exercises

M. W. Spong, S. Hutchinson, M. Vidyasagar “Robot Dynamics and Control” - Second Edition, 2004

R Siegwart and Illah R. Nourbakhsh, "Introduction to autonomous mobile robots", MIT Press, Cambridge (Mass.), 2004

Download – for a short time - from the course page

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Other booksG. A. Bekey, "Autonomous Robots - From

Biological Inspiration to Implementation and Control”, MIT Press, Cambridge (Mass), 2005.

H. Choset et al. “Principles of robot motion”, MIT Press, Cambridge (Mass), 2005.

G. Dudek, M. Jenkin, "Computational Principles of Mobile Robotics", Cambridge University Press, New York 2000.

R. L. Paul, “Robot manipulators: mathematics, programming, and control, The MIT Press, Cambridge (Mass), 1981.

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examinations

• Written – closed booksMarks: 33

+• Oral examination

questionsorstudent presentation

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In our lab: Hand eye

Maximum One (2003)

Eracle (2010)PEMGO (2011)

poliMANUS (2010)

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In our lab: legs and whegs• Ulisse (1994)• LARP (2003)• WARUGADAR(2008) • Voltron (2010)• LionHell (2012)

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In our lab: fish• ZOIDBERG (2008) - EAP• ZOIDBERG II (2010) - SMA

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summary

1. Our course2. Robots: definitions and market3. From robots to robotics4. Robot as a system

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Steps in robot history

• Mechanical: 1700 automata, karakuri-ningyo

• Fiction: 1920, “robot”• cybernetics: 1940,

turtle…• telemanipulation: 1940,

telerobot• automation: 1960,

industrial robot • Information: intelligence,

autonomy, cooperation

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Human arm• 2 coordinated arms• Each has more than 25 gdl• Integrated with vision

• Reaching• Grasping• Manipulatingkarakuri-ningyo, ~1700

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The first robots

• 1961 - "UNIMATE, the first industrial robot, began work at General Motors. Obeying step-by-step commands stored on a magnetic drum, the 4,000-pound arm sequenced and stacked hot pieces of die-cast metal.

• 1968 - Marvin Minsky developed theTentacle Arm, which moved like an octopus. It had twelve joints designed to reach around obstacles. A PDP-6 computer controlled the arm, powered by hydraulic fluids. Mounted on a wall, it could lift the weight of a person.

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Industrial robots today

•Iso - ROBOT = •automatically controlled, reprogrammable, multipurposemanipulator programmable in three or more axes. May befixed or move on wheels or rails

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Classification - manipulators

Mobilityfixedmoving on

railswheelslegscingoli

Architecturecartesianicilindricalspherical“scara”articulated3 dof, 4 dof, 5 dof, 6 dofmore than 6 dofcomplex (humanoid, etc)

Typology,parallelserialhybridmodular

Performancehigh precision and high repeatability(Cartesian, parallel- electronics, ..)medium precisione (generalmanipulation and assembly)low precisione (packaging, painting,...)

Velocityslow robot to work with high precisionfast robot ( packaging) with PTP control

Trajectorystop to stoppoint to pointcontrolledcontinuous

Controlopen loopclosed loopadaptive control

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Classification - applications

• Industrialsolderingpaintingassemblymanipulationpackaging material transfermoldingfoundrylaser 3d cuttingquality controlcombinatorial chemistrymedical analysis lab

• Specialsurgerymedical assistancerehabilitationspace applicationsmarine applicationsnuclearwararcheologicalmine removalbuilding and construction

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Telecontrolled robots

• Tele-student

• Tele-grand son

• Tele-nurse• Bomb disposal

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Human robot interface

• Telecontrol• Teleprogramming• Autonomous and proactive behavior

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Where ?

• “My guess is that in five years, there will be 10 times the number of robots deployed in hospitals that there are today,” said Donald Jones, a managing director at DraperTriangle Ventures (d. December 15, 2012), who is backingprivately held robotics company Aethon Inc. “We are just not going to have enough human hands to do all the work.”

• “Fewer than 1,000 of these blue-collar robots currentlyroam about hospitals, but those numbers are expected togrow quickly,” reports the Wall Street Journal’s Timothy Hay.

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Autonomous robot

wheregamessurveillancehomeexplorationwar

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Autonomous vehiclesThere are about 33 000 traffic deathsannually in the United Statesand 39 000 in European Union countries.

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Evolutive - modular - nanorobots

Xerox, Xerox, ParcParc

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Medical robots

surgery

exoskeleton

prosthesis implants

rehabilitation

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Space robots

Exploration, building

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IFR report 2013

MarketRobot sales in 2012 - 159,346 unitsAbout 70% to Japan, China, USA, Korea and Germany.Worldwide Japan is the first market In Europe Germany is the firstmarket

Robot density396 robot/10000 manufacturing workers in Korea273robots/1000 in Germany

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In industrial applications

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Number of robots - forecasting

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Service robots

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Service robots

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Personal robots

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This is the robot age.In the future the robots will be us”-- R. Brooks

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summary

1. Our course2. Robots: definitions and market3. From robots to robotics4. Robot as a system

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Which one is the robot?

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Imitating nature

Shape and behavior

from animals

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avatar

In the movie Avatar, humans could control giant genetically engineeredhuman-alien hybrids.

• DARPA, the U.S. Defense Advanced Research Projects Agency wantsthis kind of system to be real, just replace "giant genetically engineeredhuman-alien hybrids" with "robots."

• In its 2012 budget, DARPA has decided to pour US $7 million intothe "Avatar Project," whose goal is the following: "develop interfacesand algorithms to enable a soldier to effectively partner with a semi-autonomous bi-pedal machine and allow it to act as the soldier’s surrogate.”

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Continuum shape-action

“morphological computation”= the task are distributed between shape and material (body), control

(brain), environment

“Why do plants not have brains? The answer is actually quite simple: they don’t have to move.”Lewis Wolpert

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Sensory motor control

reflexes

Reflexes act in a way similarto neural networks

Frontal lobs

Frontal lobs act in a way similar to symbolic architectures

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Morphological computation

Tumble weedsno actuationmove with the wind

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Morphological computation in spider

8 eyes, 4 layers of cells each, sensible to different wave lenghts

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First lesson

• A robot is more than the sum of its parts

• More than mechatronicsmodularitylearninginteraction

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Robot vs robotics

Robotics = to coordinate perception and action toreach a goal

motion planning perceptiontrajectory interpretationcontrol data

to the world from the world

MO

TOR

SE

NS

ING

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Robots in ICTDisappearing computer • interfaceEmbedded system, embodied intelligence• Skills, learningInternet of thingsCognitive science• models –neuroscience

The trouble with computers is that they do what you

tell them, not what you want.

-- D. Cohen

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summary

1. Our course2. Robots: definitions and market3. From robots to robotics4. Robot as a system

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Robot as a system

subsystem MECHANICS

(arm, wheels, …)

subsystem ACTUATORS

(motors, artificial muscles, …)

subsystem CONTROL

(control loop, transformations,

subsystem PROCESS

(task, environment)

subsystem SENSORS

(internal and external)

subsystem PLANNING

(path, grasps, trajectories)

OPERATOR

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Telerobot, industrial robot, autonomous robot

control

remote environment

display sensors

actuators

remote environment

sensors

actuators C1 C2

display

control

- C2 robot controller- C1 user interface controller

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movement

internal sensor

Motor

arm

hand

base

wheel leg

joint

Link

Absolute

Reference

system

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Control unit

Controller unit

comunication action planner

perception trajectory planner

sensor interfaces controller of the movement

Teach Box

Host

Computer

Vision system

Tactile sensors

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Tele- programming and simulation

Inte

rnet

Robot

Robot controller

Server

camera

Image Server

Site 1

Site 2

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Actuators subsystem

subsystem MECHANICS

(arm, wheels, …)

subsystem ACTUATORS

(motors, artificial muscles, …)

subsystem CONTROL

(control loop, transformations,

subsystem PROCESS

(task, environment)

subsystem SENSORS

(internal and external)

subsystem PLANNING

(path, grasps, trajectories)

OPERATOR

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• traditional actuators are very rigid (stiff)•pro (precision, stability, …

•contro ( heavy, friction, more inerzia, rumore,etc)

• wanted characteristics•Elastic, compliant

•High ratio force/mass

actuators

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Rigid or flexible

• StifnessImproves positioning precision and stability, reduces errors due to external distourbance

• Stifness has a cost: electric motors have to run at high velocity to get the needed power; gears are necessary to reduce velocity.

• Gears introduce friction, are noisy, Gears have been eliminated in direct drive motors for industrial robots. However direct drive motors do not produce enough force density for mobile robots

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McKibben actuators

• Some properties of the realmuscles

• Pro: high rate force/wheight (10 newton/20 grams)

• Control: need high pressure air

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Sensors subsystem

subsystem MECHANICS

(arm, wheels, …)

subsystem ACTUATORS

(motors, artificial muscles, …)

subsystem CONTROL

(control loop, transformations,

subsystem PROCESS

(task, environment)

subsystem SENSORS

(internal and external)

subsystem PLANNING

(path, grasps, trajectories)

OPERATOR

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sensors

MANY USES:• To measure the robot parameters• To find objects• To check for collision• To monitor the environment• To inspect the result of a process

transductorSignaltransf

Signal processing

Physical entity

computer

perception

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Levels of sensorial processing

• Perceptive levelState of the worldConsequences of action

• Model levelConstruction ofgeometric levelSensorial fusion

• Measure levelSignal conversion

• Physical leveltransductor

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Sensors in biological systems

• Proprioceptive and eteroceptiveProprioceptive: muscle stress, equilibrium, …Eteroceptive: 5 senses

• More sensors act togetherMechanism of attention

• Strictly integrated in behavioursimitation

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Control subsystem

subsystem MECHANICS

(arm, wheels, …)

subsystem ACTUATORS

(motors, artificial muscles, …)

subsystem CONTROL

(control loop, transformations,

subsystem PROCESS

(task, environment)

subsystem SENSORS

(internal and external)

subsystem PLANNING

(path, grasps, trajectories)

OPERATOR

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Position and force control

• To get a precise movement, position control is used (industrial robots)

• To adapt to externalforces: force control(autonomous robots) isneeded

• In biological systems, the sensory-motor controlintegrates position and force control

Red: motor path, from brain to musclesYellow: sensing path, from receptors to brain

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Planning/programming subsystem

subsystem MECHANICS

(arm, wheels, …)

subsystem ACTUATORS

(motors, artificial muscles, …)

subsystem CONTROL

(control loop, transformations,

subsystem PROCESS

(task, environment)

subsystem SENSORS

(internal and external)

subsystem PLANNING

(path, grasps, trajectories)

OPERATOR

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Robot as a physical agent (AI)

Has sensors to build a modelof the world (objects, events, places)Builds plans to reach goalsUses learning to performbetter

AI does not explain howtoautonomously develop itsgoals

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Innate and added-on behaviours and skills

• Sensor motor actions can be “wired” – reflexes, ..• More are added after experience• From nature

No need of a hierarchical systenNo need of a central memoryNo need of symbolic reasoning

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programming

• In industrial robotics: a program completely specifiesactions and sensig activities

• In autonomous robot: some auto-programming, guided through GUI, voice commands, …

• The future: imitation learning ?