A Modular Architecture for an Interactive Real-Time Simulation and - - PowerPoint PPT Presentation

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

Slide 2

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)

Slide 3

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

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

(Ellery et al. 2008) (DEOS – DLR/STI) (SPDM on Canadarm2 - MDA) (Astronaut during EVA - DLR/ESA) (Control for Canadarm2 - MDA) (Space Debris - NASA)

Slide 4

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

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

Slide 5

Bimanual Haptic Interface

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

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

Slide 6

Physical Mock-up

• Tele-Presence Interface demonstrated at ILA 2010 in Berlin

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

Slide 7

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)

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

Operator

at Ground Control

VR Environment Service Robot

in Space

Slide 8

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)

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

Virtual Satellite Mock-up EVA Task Sheet Physical Satellite Mock-up

Slide 9

System Components

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

Slide 10

Requirements

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

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

>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?

Slide 11

Distributed Simulation Architecture

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

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

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

Slide 12

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

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

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

Slide 13

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)

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

static body A hinge joint J

Fsw αmin αmax

kinematic body C

xC xB xA FH

Slide 14

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

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

Slide 15

Contact

Robin Wolff robin.wolff@dlr.de 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

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