a modular architecture for an interactive real-time ...c4i.gmu.edu › eventsinfo › conferences...

A Modular Architecture for an Interactive Real-Time Simulation and Training Environment for Satellite On-Orbit Servicing

Slide 1

Robin Wolff German Aerospace Center (DLR), Germany

VR-OOS > Robin Wolff > DS-RT 2011 > 06.09.2011


Outline

!  Motivation !  Physical Mock-up !  Project Goal

!  System Overview !  Servicing Tasks !  System Components

!  Distributed Simulation Architecture !  Framework Structure !  Communication Layer !  Implemented Modules

!  Summary (Servicing the Hubble Space Telescope - NASA)

Motivation

!  On-Orbit Servicing !  Analyse & Repair Failures !  Lifetime Extension

!  Remove Space Debris !  Manned Missions

!  Expensive and Risky !  Exhausting for Astronauts

!  Increased Use of Space Robots

!  Autonomous Operation !  Controlled via Tele-Operation


(Ellery et al. 2008)

(DEOS – DLR/STI)

(SPDM on Canadarm2 - MDA)

(Astronaut during EVA - DLR/ESA)

(Control for Canadarm2 - MDA)

(Space Debris - NASA)

Humanoid Service Robot

!  Light Weight Robot (LWR) !  7 Axes !  Weight: 14kg, Payload: 14kg

!  Space Justin !  49 Joints !  Sensors

!  Stereo Camera !  Laser Stripe Sensor !  41 Position Sensors !  43 Torque Sensors

!  Workspace: approx. 1.7m !  Weight: 45kg, Payload: 15kg


Bimanual Haptic Interface

!  Based on LWR !  Bimanual Control !  Magnetic Safety Linkage !  Tracking via Rotation Sensors in Joints !  Haptic Feedback via Robot’s Motors


Physical Mock-up

!  Tele-Presence Interface demonstrated at ILA 2010 in Berlin


Project Goal

!  Create an Immersive Virtual Environment for the Simulation of On-Orbit Servicing Tasks

!  Applications: !  Analysis, Training, Programming

& Tele-Operation of On-Orbit Servicing Tasks

!  Design of new serviceable Satellite Systems

!  Design of new Service Robots and Tools

!  Project Partners: !  DLR Robotics and Mechatronics !  DLR Simulation and Software Technology

!  Project Time 3 years (started Jan 2010)


Operator at Ground Control

VR Environment

Service Robot in Space

Servicing Tasks

!  Remove Multi-Layer Insulation (MLI) !  Loosen / Tighten Screws !  Plug / Unplug Cable Connectors !  Remove / Insert Modules

(using a Bayonet Handle) !  Operate Switches !  Take Measurements

(e.g. using a Voltmeter)


Virtual Satellite Mock-up

EVA Task Sheet Physical Satellite Mock-up

System Components


Requirements

!  Real-Time Requirements !  Highly Realistic Simulation !  Complexity vs. Accuracy !  Dedicated Machines


>1kHz

30-60Hz

Haptic Device

Visualization

Manager

Physics Simulation ~60Hz

GPU

Logic

Tele-Robot F

x

F x

x

x

F F

!  Shared Functionality? !  Duplicate Code? !  Shared Scene Description?

Distributed Simulation Architecture

!  Wraps Common Functionality !  Unified Scene Management !  Transparent Processing Loop !  Asynchronous Message Passing !  Modular Architecture !  Generic Structure !  Common Interface !  Easily Extensible


Server Client Client Client

Physics

Scene Simulation

Communication

Visualization

Scene Simulation

Communication

Haptics

Scene Simulation

Communication

Manager

Scene Simulation

Communication

…

Update Simulation

Step Simulation

Distribute Changes

Interpret Updates

Collect Changes

Common

Spec.

Simulation State

Read & Modify

Recv. Send.

Common Processing Loop

Communication Layer

!  Configurable Queuing Schemes !  FIFO (Default for State Changes, Commands) !  Most-Recent (Default for Updates)

!  Refresh & Distribution Lists !  Queue only relevant Nodes

!  Threshold Filter !  Send only “significant” Changes

!  Update Rate Monitor !  Caps Update Frequency if too high

!  Online Performance Monitoring !  Keeps an Eye on System Status !  Future: Automatic Reconfiguration


A A A

C B A

B B

D

D C C

Scene

C B A D changed distribute

∆x

C B A D distribute

t0 t0+T t1+T

Implemented Modules

!  Haptic Device !  Interface to HMI, Phantom Omni, Falcon

!  Collision Detection !  Based on Voxmap-PointShell,

and OpenHaptics !  Visualization

!  Based on ViSTA VR-Toolkit, and InstantReality

!  Physics !  Based on Bullet

!  Manager !  Based on Behavior Classes

(in Future: Python)


static body A

hinge joint J

Fsw αmin αmax

kinematic body C

xC

xB

xA

FH

Summary

!  Modular Architecture for a Distributed Interactive Real-Time Simulation Environment !  Provides Underlying Infrastructure

for Research Modules !  First Prototype demonstrated

!  Desktop, 3D-TV + Haptics !  VR Display (Powerwall)

!  Further Work !  Enhance Photo-realistic Rendering !  Test other Physics Engines !  GPU Implementation of VPS Algorithm !  Increase Complexity of Scenes !  Enable Distributed Collaboration


Contact

Robin Wolff [email protected]

Simulation and Software Technology, Software for Space Systems and Interactive Visualization (SC-RV)

German Aerospace Center (DLR), Lilienthalplatz 7, 38108 Braunschweig, Germany

http://www.dlr.de/sc/en


a modular architecture for an interactive real-time ...c4i.gmu.edu › eventsinfo › conferences...

Documents