Mobile Robotics Lab Workshop on Grasp Planning and Task Learning by - - PowerPoint PPT Presentation

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Mobile Robotics Lab Workshop on Grasp Planning and Task Learning by - - PowerPoint PPT Presentation

Mobile Robotics Lab Workshop on Grasp Planning and Task Learning by Imitation IROS 2010 Taipei, Taiwan Institute of Systems and Robotics Institute of Systems and Robitcs http://paloma.isr.uc.pt University of Coimbra Symbolic level


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University of Coimbra

Institute of Systems and Robitcs

http://paloma.isr.uc.pt

Institute of Systems and Robotics

Mobile Robotics Lab Workshop on Grasp Planning and Task Learning by Imitation

IROS 2010 – Taipei, Taiwan

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University of Coimbra

Symbolic level generalization of in-hand manipulation tasks from human demonstrations using tactile information

Ricardo Martins, Diego R. Faria and Jorge Dias

Ricardo Martins

http://www.isr.uc.pt/~rmartins/ Taipei, Taiwan 18th August 2010

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University of Coimbra

Contents

  • Introduction
  • Approach Overview
  • Contact Templates Definition
  • Contact Templates Detection
  • Conclusions
  • Future Work
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Development of robotic systems able to interact in new dynamic, unpredictable environments:

  • Domestic, healthcare, entertainment, education.
  • New challenges: Interaction Robots & Humans, Interaction Robots & Environment
  • Development of mobile robotic platforms:
  • Multimodal sensing capabilities:

+ Active vision + Audition + Multi Articulated Arms + Dexterous hands + …

  • Emergence of integration recognition, interaction and learning issues.

I - Introduction

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Evolution:

simple gripper human inspired articulated hands

  • Development of human inspired robotic hands:

Anatomy: Move from simple grippers towards human inspired articulated hands. Physiology: Introduction of sensing devices (tactile, temperature, force/torque sensors)

I - Introduction

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  • The neuroscience literature (Johansson and Flanagan, 2009) proposes a

decomposition of a typical human manipulation movement on different stages

  • reach -load -lift -hold -replace -unload

I - Introduction

Reach Load Lift Holding Replace Unload Digits contact

  • bject

Object lifts off surface Object approachs manipulation height Object contacts surface Digits release

  • bject
  • In-Hand Manipulation
  • The internal consecutive regrasping and release of the object
  • Perform object reorientation, fine positioning or more complex interaction.
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  • Representation of the general contact signatures for manipulation tasks developed
  • n some daily activities

I - Introduction

  • N. Kamakura, Te no ugoki, Te no katachi (in Japanese), Ishiyaku Publishers, Tokyo, Japan, 1989.
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  • Challenge:
  • How to learn and encode the human like skills/capabilities?
  • Develop a compact and flexible representation for:

+ task recognition + task planning + task synthesis

  • Imitation Learning à

à Task representation

I - Introduction

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II – Approach Overview

  • Generalization at a trajectory level:

Adapted from Billard et al, 2008

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University of Coimbra Adapted from Billard et al, 2008

II – Approach Overview

  • Generalization at a symbolic level:
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Overview of the global structure of the proposed system

II – Approach Overview

Environment Multifingered Robotic Hand Effector Hand Tactile Sensing Array Sensing Devices Contact State Sequence Posterior Tactile Discretization Sensory Processing Contact State Primitives Templates Pior Knowledge Task Constraints Gain/Loss Function Sensation Perception Action Decision Rule Bayesion Approach

  • The human subjects performs an in-hand manipulation task using a instrumented

glove (hand joint flexure sensors and tactile sensors)

  • Elementary primitives sequence extraction among a pre-defined primitive set.
  • Verification if the raw sequence of primitives extracted from the demonstration

respects the constraints of that class.

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III –Contact Template Definition

Primitive model definition

  • The output of the 360 tactile sensing

elements are grouped on 15 regions.

  • Each region corresponds to different areas
  • f the hand.
  • A variable Ti is assigned to each of this

regions: T = { T1, T2,…, T15}

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III –Contact Template Definition

} , , {

15 ,..., 1

HighActive LowActive NotActive Ti

i

∈ ∀ =

T1 T2 T6 T10 T14 T3 T4 T5 T7 T8 T12 T9 T13 T11 T15

Primitive model definition

  • A variable Ti is assigned to each of this

regions: T = { T1, T2,…, T15}

  • Domain definition of each variable:
  • NotActive à 0 < Ti < 25
  • LowActive à 26 < Ti< 190
  • HighActive à 190 < Ti < 255
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III –Contact Template Definition

Primitive set definition

  • The set of primitives comprises a total of 7

templates.

  • A primitive is designed by the variable E.
  • The domain definition of E is:

E ε {primitive1, primitive2, …, primitive7}

Primitive1 Primitive2 Primitive3 Primitive4 Primitive5 Primitive6

  • Primitive7 àno contact between the hand and the object.
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III –Contact Template Definition

Primitive set training

  • Estimation of the parameters T of each of

the predefined primitives E

  • Human demonstration of each of the 7 pre-

defined primitives à static contact configuration of the human hand and the

  • bject.
  • From each primitive demonstration a

probabilistic distribution is built à P(T/E)

Primitive1 Primitive2 Primitive3 Primitive4 Primitive5 Primitive6

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III – Contact Template Definition

Experimental Results

  • Estimation of the parameters T of each of the pre-defined contact state templates
  • Five demonstrations of each grasp configurations

Trial 01 Trial 02 Trial 03 Trial 04 Trial 05 T1 H H H H L T2 H H H H L T3 N N N N N T4 N N N N N T5 N N N N N T6 N N N N N T7 N N N N N T8 N N N N N T9 N N N N N T10 N N N N N T11 N N N N N T12 N N N N N T13 N N N N N T14 N N N N N T15 N N N N N

Primitive 1 trainning result

tk P(T=tk / E=primitive1) (H,H,N,N,N,N,N,N,N,N,N, N,N,N,N) 4/5 (L,L,N,N,N,N,N,N,N,N,N,N ,N,N,N) 1/5 Other

Primitive 1 - Conditional Probability Density Function N-NotActive L-LowActive H-HighActive Primitive1

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III – Contact Template Definition

Experimental Results

tk P(T=tk / E=primitive2) (N,L,H,H,L,L,H,H,L,N,N,N, N,N,H) 2/5 (N,L,H,H,L,N,L,L,N,N,N,N, N,N,H) 1/5 (N,L,H,H,N,N,L,L,N,N,N,N, N,N,H) 2/5 Other

Primitive 2 - Conditional Probability Density Function N-NotActive L-LowActive H-HighActive

tk P(T=tk / E=primitive3) (H,H,H,H,L,H,H,L,L,H,L,L, N,L,N) 3/5 (H,H,H,H,N,H,H,L,N,H,L,L, N,L,N) 2/5 Other

Primitive 3 - Conditional Probability Density Function

tk P(T=tk / E=primitive4) (H,N,H,N,N,N,L,N,N,N,N,N ,N,N,N) 2/5 (H,N,H,N,N,N,N,N,N,N,N, N,N,N,N) 3/5 Other

Primitive 4 - Conditional Probability Density Function Primitive2 Primitive3 Primitive4

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III – Contact Template Definition

Experimental Results

Primitive 5 - Conditional Probability Density Function N-NotActive L-LowActive H-HighActive

tk P(T=tk / E=primitive6) (L,L,L,L,L,H,H,H,L,N,N,N, N,N,H) 2/5 (L,L,L,L,N,H,H,H,L,N,N,N, N,N,H) 3/5 Other

Primitive 6 - Conditional Probability Density Function

tk P(T=tk / E=primitive7) (N,N,N,N,N,N,N,N,N,N,N, N,N,N,N) 1 Other

Primitive 7 - Conditional Probability Density Function Primitive5 Primitive6

tk P(T=tk / E=primitive5) (H,H,H,H,H,N,N,N,N,N,N, N,N,N,N) 1/5 (H,H,H,L,L,N,N,N,N,N,N,N ,N,N,N) 2/5 (H,H,L,N,N,N,N,N,N,N,N,N ,N,N,N) 2/5 Other

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IV – Contact Template Detection

Primitives detection on raw data input

  • The raw data input produced by the human demonstration is integrated during equal

time intervals of length t.

  • The integrated data during each time slot t à Tt
  • The primitive with the maximum likelihood is the template assigned to that timeslot.

) ( ) ( ) / ( ) / ( T T T

t t t

P E P E P E P =

From the primitives demonstration trainning session P(E)=1/7

∑ =

= = = = = = = = =

7 1 15 1 15 1 15 2 1

) ( ) / ) ,..., / ( ) ( ) / ) ,..., ( ( )) ,..., , ( / (

j j j t i i t i t

primitive E P primitive E t t P primitive E P primitive E t t P t t t primitive E P T T T

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IV – Contact Template Detection

Experimental Setup

  • Human demonstrator
  • Right handed instrumented data glove
  • Tactile sensing
  • Tactile sensing array data acquisition

rate: 500Hz

  • Cup
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IV - Contact Template Detection

Experimental Results

  • Task I – Reorientation of the mug in order to place the grasp of the mug in a

configuration suitable to be grasped by the handle by the subject.

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IV – Contact Template Detection

Experimental Results

Timeslot (ms) Trial 01 Estimation 0-500 (N,N,N,N,N,N,N,N,N,N,N,N,N,N,N) primitive7 500-1000 (N,N,N,N,N,N,N,N,N,N,N,N,N,N,N) primitive7 1000-1500 (H,H,N,N,N,N,N,N,N,N,N,N,N,N,N) primitive1 1500-2000 (N,N,N,N,N,N,N,N,N,N,N,N,N,N,N) primitive7 2000-2500 H,H,H,L,L,N,N,N,N,N,N,N,N,N,N) primitive5 2500-3000 (N,N,N,N,N,N,N,N,N,N,N,N,N,N,N) primitive7 3000-3500 H,H,L,N,N,N,N,N,N,N,N,N,N,N,N) primitive5 3500-4000 H,H,H,L,L,N,N,N,N,N,N,N,N,N,N) primitive5 4000-4500 (N,N,N,N,N,N,N,N,N,N,N,N,N,N,N) primitive7 4500-5000 H,H,L,N,N,N,N,N,N,N,N,N,N,N,N) primitive5 5000-5500 (N,N,N,N,N,N,N,N,N,N,N,N,N,N,N) primitive7 Timeslot (ms) Trial 02 Estimation 0-500 (N,N,N,N,N,N,N,N,N,N,N,N,N,N,N) primitive7 500-1000 H,H,H,H,H,N,N,N,N,N,N,N,N,N,N) primitive5 1000-1500 (N,N,N,N,N,N,N,N,N,N,N,N,N,N,N) primitive7 1500-2000 (H,H,H,H,H,N,N,N,N,N,N,N,N,N,N) primitive5 2000-2500 (N,N,N,N,N,N,N,N,N,N,N,N,N,N,N) primitive7 2500-3000 (H,H,L,N,N,N,N,N,N,N,N,N,N,N,N) primitive5 3000-3500 (N,H,N,N,N,N,N,N,N,N,N,N,N,N,N) Not recognized 3500-4000 (N,N,N,N,N,N,N,N,N,N,N,N,N,N,N) primitive7

Task I – Trial 02 Task I – Trial 01

Primitive1 Primitive5 Primitive5

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IV – Contact Template Detection

Experimental Results

  • Task II – Grasping the mug without reorientation and elevate it.
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IV – Contact Template Detection

Experimental Results

Timeslot (ms) Trial 01 Estimation 0-500 (N,N,N,N,N,N,N,N,N,N,N,N,N,N,N) primitive7 500-1000 (H,H,L,N,N,N,N,N,N,N,N,N,N,N,N) primitive5 1000-1500 (H,H,H,H,N,H,H,L,N,H,L,L,N,L,N) primitive3 1500-2000 (H,H,H,H,L,H,H,L,L,H,L,L,N,L,N) primitive3 2000-2500 (H,H,H,H,L,H,H,L,L,H,L,L,N,L,N) primitive3 Timeslot (ms) Trial 02 Estimation 0-500 (N,N,N,N,N,N,N,N,N,N,N,N,N,N,N) primitive7 500-1000 (H,H,H,H,L,H,H,L,L,H,L,L,N,L,N) primitive3 1000-1500 (H,H,H,H,L,H,H,L,L,H,L,L,N,L,N) primitive3 1500-2000 (H,H,H,H,L,H,H,L,L,H,L,L,N,L,N) primitive3

Task II – Trial 02 Task II – Trial 01

Primitive3 Primitive5 Primitive3

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V – Conclusions

  • Typically the first segments correspond to template of primitive7- no contact hand
  • bject.
  • Task I
  • Sequence of grasp and release of the object.
  • Fingers involved on the reorientation are predominantly the thumb, index and

middle fingers.

  • The magnitude of the tactile inputs and number of fingers mobilized is higher

during the initial grasp-release cycles.

  • Task II
  • The movement is decomposed in primitives that involve the participation of

high extensions of fingers surface.

  • Simple prehension movement – transport – contact signatures still the same

along the time

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VI – Future Work

  • Perform tests on additional types of tasks
  • Automatic definition of the primitive set
  • Implementation of the task primitive sequence representation constraints

extraction.

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ISR-UC End

Institute of Systems and Robitcs

http://paloma.isr.uc.pt

  • Institute of Systems and Robotics