Simulating the Motion of a Nonholonomic Robot and Its Trailer

Abstract

This paper describes an algorithm for simulating the motion of a nonholonomic robot vehicle and its trailer. The algorithm assumes that both the vehicle and its trailer move along circular arcs when the incremental time step used to update position and heading is small. The purpose of the simulation is to accurately represent the motion of a Navigation Test Vehicle (NTV) so that the ability of a vehicle’s control algorithm to track an explicit path can be evaluated. An auto-tuning algorithm is currently being developed in simulation to autonomously tune the control parameters for a nonholonomic robot vehicle, and this will require an accurate representation of the kinematics of the NTV. An accurate representation of the trailer motion is necessary to develop an autonomous backing-up control algorithm and path tracking control algorithms where the control point is on the trailer. As with the NTV, the positioning subroutine of the simulation program provides the control algorithm with vehicle and trailer pose data at 10 Hz. Locally, the positioning subroutine updates this data at 0.01 second intervals. The simulation currently runs on a Silicon Graphics IRIS Crimson/VGX workstation.