Formation control of multiple nonholonomic mobile robots

Abstract

AbstractTracking control problem of multiple mobile robots is considered. Our system is composed of a reference and follower robots of unicycle type. The robots are assumed to satisfy pure rolling and nonslipping conditions, which lead to nonholonomic constraints. The purpose is to control the followers so that the reference is tracked with arbitrary desired clearance and also to avoid interrobot collisions. To accomplish this goal, we first introduced a virtual robot (VR) tracking control to establish and maintain the formation when no collision is detected. VR is an ideal robot fixed with each follower and helps in simplifying the control, as the tracking error becomes zero in the final stage. During the process, if the possibility of collision is detected, a collision avoidance technique (l−ψ or l−l control) will be applied to the lower priority robot. The result of this control gives a monotonic convergence in an internal shape of distance variables, which enables us to predict the movement of the robots during this control and leads to collision‐free movement. These processes are repeated until the desired motion is accomplished. Simulation results prove the efficiency of our control techniques. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(3): 81–88, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20192 Copyright © 2006 Wiley Periodicals, Inc.