BERRY IV was constructed by Christian Balkenius and Lars Kopp during 1993 and was our first mobile robot to reach some level of sophistication. It was designed to interact with a remote computer through a radio link. Visually based behaviors were controlled by the remote computer while tactile avoidance and wall following were handled directly by the robot.

What Can It Do?

The following behaviors have been succesfully implemented in the robot:

  • Tactile Avoidance The four whiskers and the front bumber are used to activate avoidance behaviors. Different patterns of tactile signals are classified and a priority ordering of the applicable behaviors is used to select the appropriate avoidance behaviors.
  • Simple Visual Avoidance A simple texture recognizing algorithm has been implemented. Since the lens of the robot is adjusted to only give a sharp image at a close range, texture in the image indicates that an obstacle is present. The visual analysis is used to avoid textured obstacles.
  • Tactile Wall Following Wall following has been implemented as a competition between two behaviors. Attraction towards a wall when it is far away and avoidance of it when it is close. Wall following start when the whisker on one of the sides of the robot comes in contact with a wall (or other obstacle).

Technical Specification

  • 1 Miniboard (a HC11 based microcontroller)
  • 1 Radio Receiver
  • 1 Pulnix 526 CCD Camera on a movable head
  • 1 Bumber
  • 4 Whiskers
  • 2 Geared Motors