Robotic Deformable Object Cutting From Simulation to Experimentation - PowerPoint PPT Presentation

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Robotic Deformable Object Cutting From Simulation to Experimentation Philip Long, Wisama Khalil and Philippe Martinet IRCCyN ´ Ecole Centrale de Nantes March 20, 2014

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Overview Goal Simulation and experimental validation of a force/vision controller to separate soft materials

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Overview Robotic Cell Behavior Introduction 1 Graphical Results Summary Experiments Motivation 5 Objectives Simulation 2 Robot Control Objectives Cell Modeling Experimental Results 6 Robot Behavior Cutting Strategy Graphical Results Control Scheme 3 Global Control Scheme Future Work 7 Robot Control Force Image Control Simulator Results Questions 4

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Motivation Meat processing industry is the largest sector of food industry in France [1] Hazardous, strenuous and uncomfortable working conditions leading to a high rate of musculoskeletal injuries Robotization of meat separation process has been shown to increase both hygiene and accuracy in the manufacturing environment [2] Robotic cutting has so far been limited to highly repeatable separation scenarios

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work ARMS Project ARMS: A multi arms robotic system for muscle separation ANR ARPEGE funded project contributing to the robotization of the meat processing industry A multi-arm system that can separate variable beef muscles arms.irccyn.ec-nantes.fr

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Contents Robotic Cell Behavior Introduction 1 Graphical Results Summary Experiments Motivation 5 Objectives Simulation 2 Robot Control Objectives Cell Modeling Experimental Results 6 Robot Behavior Cutting Strategy Graphical Results Control Scheme 3 Global Control Scheme Future Work 7 Robot Control Force Image Control Simulator Results Questions 4

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Objectives 1. Modeling Design of a robotic cell simulator that accurately represents the interactions and challenges of the meat cutting environment Simulator can be used to optimize robot and cell position, test redundancy resolution and simulation of control schemes 2. Control Propose a control scheme that is able to complete separation task Control scheme uses force and vision sensor to cope with online changes

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Summary Modeling & Control of Robotic Meat Cutting Cell Global control of robotic cell in order to separate meat muscle Force vision strategies to cope with object deformation

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Simulator Global View Simulink Controller Force Trajectory Controller Generator Visual Position Deviation Controller Force Feedback Joint Velocities Visual Feedback Position Feedback Mode Shapes FEM Dynamic Simulator

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Deformable Object Modeling I Specifications: 3D scan of beef shoulder Cutting surface is extracted Muscles rebuilt using FEM

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Deformable Object Modeling II Description: Beef Muscle 1 Beef Muscle 2 3 deformable models are created[3] Aponeurosis Muscles are meshed using FEM Aponeurosis (tendons that link the muscles) are modeled using Cutting FEM FEM Path spring damper Spring-Damper systems System

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Cutting Strategy Cutting Relations p c must be below the virtual spring-damper, z c ≤ min ( z 1 , z 2 ) p c must lie within the bounding box ( b 1 . . . b 4) The projection of p c must lie on the line segment | a 1 a 2 | b.1 b.2 b.3 b.4

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Visual Information Vision Extraction: Vision data is obtained from attachment points’ position The data is used to reconstruct an interpolated surface from which a trajectory can be obtained

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Contents Robotic Cell Behavior Introduction 1 Graphical Results Summary Experiments Motivation 5 Objectives Simulation 2 Robot Control Objectives Cell Modeling Experimental Results 6 Robot Behavior Cutting Strategy Graphical Results Control Scheme 3 Global Control Scheme Future Work 7 Robot Control Force Image Control Simulator Results Questions 4

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Robotic Cell Controller Feature Guide Line Extraction Local Update Trajectory Position Generator Controller t Cutting Robot Vision Pulling Robot System Trajectory Impedance Generator Controller Optimize FOV Vision Robot

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Cutting Robot Initial State On-line Deformation Description: For each passage a curve is fitted to the surface Local Update 5 degree polynomial x d and trajectory gives x d ,˙ X x d ¨ Y A local update is used to compensate for online deformation/poor τ i = A i w + H approximation y ∗ d ( t ) = y d ( t ) + ∆ y ∆ y = y g − y c

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Pulling Robot Description: Impedance controlled around a defined set point A desired force is given in the pulling direction As the Aponeurosis are severed the h p meat opens gradually x d = ¨ x ) + K p (∆ x ) − K f (∆ h )) − ˙ ¨ x + λ ( K d (∆˙ J i ˙ q

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Vision Robot Description: Controlled to optimize field of view Field of View Robot moves to avoid occlusions x d = − λ L + ˙ s ( s d − s im )

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Contents Robotic Cell Behavior Introduction 1 Graphical Results Summary Experiments Motivation 5 Objectives Simulation 2 Robot Control Objectives Cell Modeling Experimental Results 6 Robot Behavior Cutting Strategy Graphical Results Control Scheme 3 Global Control Scheme Future Work 7 Robot Control Force Image Control Simulator Results Questions 4

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Control of a Meat Cutting Robot Simulator

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Redundancy Resolution of Robotic Cell Redundancy Resolution of multi-arm system

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Cutting Results- Cutting Trajectory Passage 4 0.075 0.07 0.065 0.06 0.055 y(m) 0.05 Interpolation(t0) 0.045 Surface(t0) Surface(t) 0.04 Robot(t) 0.035 0.03 0.4 0.45 0.5 0.55 0.6 0.65 0.7 x(m)

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Cutting Results- Pulling Force Time (s)

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Contents Robotic Cell Behavior Introduction 1 Graphical Results Summary Experiments Motivation 5 Objectives Simulation 2 Robot Control Objectives Cell Modeling Experimental Results 6 Robot Behavior Cutting Strategy Graphical Results Control Scheme 3 Global Control Scheme Future Work 7 Robot Control Force Image Control Simulator Results Questions 4

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Review of Dynamic Simulator Advantages Simulation of complex dynamic control schemes Contact simulation with realistic flexible objects Visualization of resulting behavior Disadvatages 1 Separation is carried out in intermediate region between objects → no force feedback on knife 2 Simulation of idealistic vision system limited to spring attachment points

Introduction Simulation Control Scheme Simulator Results Experiments Experimental Results Future Work Experimental Setup Motivation 1 Validate controller using local update by vision 2 Use sensed forces to control cutting tool Setup