Position Tracking Control of Four-wheel Independently Driven Mobile Platforms Using Longitudinal Tire Force Control Algorithms

In recent years, more and more mobile platforms are applied to transporting goods, tour guiding, patrolling, etc. Kinematic controllers are widely used in differential-drive mobile platforms for their simple structures; however, as the speed of the mobile platform increases, the performance of the kinematic controller deteriorates because of the non-negligible effects of vehicle dynamics and violation of the rolling-without-slipping assumption on the wheels. This paper proposes a hierarchical control structure that consists of an upper controller for dealing with vehicle dynamics, a tire force distribution algorithm that makes optimal use of tire forces, and a lower controller that considers the tire dynamics to track the desired longitudinal tire force. Experiments are conducted based on a four-wheel independently driven mobile platform. The results show that the proposed controller can track the reference trajectory more accurately than the kinematic controller, especially for the high-speed motion.