Scarecrow: An Implementation of Behavioral Control on a Mobile Robot

Abstract

Traditional planning and programming techniques for mobile robot control do not do well in unknown and unstructured environments. The successful implementation of a control strategy for an autonomous mobile robot is presented where the motion of the vehicle is strictly based upon the integrated response of multiple uncoupled primitive reflexive behaviors which incorporate no planning. We previously demonstrated the resulting motion of a robot based upon this approach by using computer simulation. Those results show that such a robot is capable of performing many relatively complex tasks in unknown environments, with only a limited set of such primitive behaviors. In this paper, the hardware and software implementation issues required to bring these concepts into reality on an actual machine are discussed. These issues include range sensor interfacing, communications between multiple on board processors, real time control within an object-oriented environment, robot safety, and robustness in the presence of sensor error. The resulting motion of an actual mobile robot, Scarecrow, is then compared with the simulation results for a number of different higher level behaviors. The observed behavior was found to be similar to that predicted by simulation, despite significant sensor limitations.