Multiple Robot Simulation MRS system

1
Multiple Robot Simulation (MRS) system

• Robotics Laboratory
• Lab routine presentation
• Sylvia Cheong
• March 07, 2002

2
Outline

• Brief introduction
• Previous work on IRIS project
• Current project status on IRIS project
• New robot models and enhancement of MRS
• Future work

3
Introduction

• MRS is a 3D graphical robotic simulation tool,
  written in C.
• Using MRS to simulate robot kinematic behaviour
• Unix version rendering using Open Inventor on
  the IRIX 6.5 platform
• PC version rendering using OpenGL on the Win32
  platform

4
Introduction (contd)

• MRS features listed
• Forward and inverse kinematics
• Workcell planning
• Trajectory planning
• Grasping
• Remote control
• Collision detection

5
Previous Work

• An external remote controller was implemented,
  called as nettest
• Written in C
• Using TCP/IP protocol and Workcell Control
  Protocol (WCP)
• Remote control to change base position and
  orientation of the robots and/or objects

6
Current Project Status

• The final integration of IRIS Flexible
  Fixtureless Assembly (FFA) workcell
• A more well-defined Common Object Request Broker
  Architecture (CORBA) interface
• supports a full functional client-server
  communication between the FFA supervisor and MRS
  system
• allows various platform type of clients to
  interact with MRS system

7
MRS Remote Control Interface

• Use Case
• The Remote Control (RC) System acts as a bridge
  between FFA Supervisor and the MRS system.
• For example, information is sent from FFA
  Supervisor to MRS for simulation and
  visualization, so that the user may monitor the
  Robot(s) behaviour in MRS virtual workcell

8
MRS Remote Control Interface
9
MRS Remote Control Interface

• CORBA and CorbaScript versions
• CORBA ORBacus (version 4.0)
• Naming service
• Concurrency model single-thread model
• Server side, by default set to reactive model
• Client side, by default set to blocking model
• Creating thread, using JTCThread if necessary
• is a Java-like Threads for C
• CorbaScript (version 1.3.3)

10
MRS Remote Control Interface

• Both server and client are written in C
• Requires good understanding of C and CORBA
• RC provides service for remote controlling the
  workcell elements in MRS
• Changing robot joint angles

11
MRS Remote Control Interface

• OMG IDL descriptions extracted from the Interface
  Repository and are made directly available to
  scripts
• no OMG IDL stub or skeleton needs to be generated
• a much more user-friendly interface for the user
• retrieving usefully data from the server side for
  information update and error checking

12
MRS Remote Control Interface

• Server side
• More interface functions
• Fundamental communication interfaces
• Used to have 4 interface functions only
  setipName ( ), selectWorkcellid ( ), selectMode (
  ) and setVar ( )
• More interfaces have been added to current design
  for updating workcell element information and
  error checking from the client side including
  getBaseMode ( ), getBaseVar ( ), getTrajTime ( )
  getTrajectoryDelay ( ) and other get function
  interfaces
• Controlling delay time and trajectory iterations
• Numerical calculation functions support for the
  client, e.g., inverse kinematics

13
MRS Remote Control Interface

• FFA workcell consists of 3 FanucS400 robots
• Using JTCThread to provide the thread features
• plan trajectory for 3 robot workcell elements
  simultaneously
• send starting and ending values for 3 robots
• server takes care of the threading work, to spawn
  and send appropriate data to MRS
• using JTCThread, rather than receiving 3 thread
  requests from 3 different clients
• Eliminate the delaying execution of client
  request

14
MRS Remote Control Interface

• Client side
• CorbaScript eliminates re-compilation to add new
  processes
• no ffa_Client.exe executable file is generated
• CorbaScript provides a dynamic binding to OMG IDL
  descriptions
• The client CorbaScript Interpreter interprets the
  client script to set and get the workcell element
  data from the server

15
MRS Remote Control Interface Implementation
16
MRS Remote Control Interface Implementation

• Interface Definition Language (IDL) both server
  and client share the same idl file
• Constructor/destructor only used by the server
  itself
• Connection sets up the connection between FFA
  server and MRS system

17
MRS Remote Control Interface Implementation

• Calculation presents the adaptor functions for
  pre-processing input data from the client, sent
  to MRS
• Data export used for data transferring
• All the data, including joint variables of the
  workcell element (robot) and the Cartesian
  (base/end-effector) frame of the robot is
  required to invoke these functions

18
MRS Remote Control Interface Setup

• MRS server
• Start MRS by double clicking on the MRS icon, and
  load the FFA workcell
• Naming server
• Interface repository server
• FFA RC server
• FFA RC client

19
MRS Remote Control Interface

• Finalized the IRIS FFA workcell
• Verified robotics simulation and planned
  trajectories for FFA workcell
• Export trajectory data to CorbaScript data format
• Improved graphical interface (3-button mouse
  control)
• Documented the software

20
MRS robot models
MRS robot models from left to right, back row
Puma 760 and FanucS400 Front row CRSF3, Puma 560
and Redisetro (Red1).
21
MRS robot models
22
Future works IRIS FFA and MRS

• MRS User manual
• MRS RC Interface User manual