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LRF

Laser Range Finder (LRF)

• Laser Range Finder is used to help the robot avoid hitting barriers.
• Our robot uses "SICK LMS200" LRF
  • The Laser Rangefinder is connected to serial port 1 on the robot's P4 computer (visionmcp).
  • After login, start "player" with the laser config file. Run command: "player laser.cfg &"
  The player reads the LRF data, and makes them available via network.
  • The config file contains hardware type, resolution information.

    driver
    (
      name "sicklms200"
      provides ["laser:0"]
      port "/dev/ttyS1" #serial port 1
      resolution 50   # angle resolution 0.5 degree
      range_res 1      # Range resolution 1 mm (maximumrange 8.192m)
    )
    
  • Bring up the player client -- "playerv", which read the data from network, and display it graphically. Run command: "playerv &"
  • From the "playerv" menu, subcribe to laser, you will see the range information in a picture.
• Sample pictures:
  • Photo 1: a chair on the left side.
  • Photo 2: Moved the chair to the right side and closer to the LRF.
• Player client code to read laser input:

#include <iostream>
#include <libplayerc++/playerc++.h>

/*
 g++ -o try_laser `pkg-config --cflags playerc++` try_laser.cpp `pkg-config --libs playerc++`

*/

int
main(int argc, char *argv[])
 {
  using namespace PlayerCc;
  double r1, r2, r3;

  PlayerClient    robot("localhost");
 //  SonarProxy      sp(&robot,0);
 //  Position2dProxy pp(&robot,0);
  LaserProxy lsp(&robot,0);

  for(;;)
  {
    // read from the proxies
    robot.Read();
    r1 = lsp.GetRange(100);
    r2 = lsp.GetRange(200);
    r3 = lsp.GetRange(300);
    // print out data
    std::cout << r1 << " " << r2 << " " << r3 << std::endl;
  }
 }

• References:
  • Player/Stage/Gazebo Homepage: http://playerstage.sourceforge.net/