Cooperative Control of Autonomous Mobile Robots in Unknown Terrain

This paper presents a distributed control framework for groups of wheeled mobile robots with significant (non-negligible) vehicle dynamics driving on terrain with variable performance characteristics. A dynamic model of a high-speed robot is developed with attention to representation of wheel-terrain performance characteristics. Using this model, aspects of distributed, cooperative control on unknown terrain are investigated. A potential function path planning and cooperative control algorithm is combined with a local slip controller on each robot to provide high-speed control of vehicle formation. Local slip control is shown to reduce sensitivity of the distributed path planning and control method to tire-terrain performance variation and its resulting effect on dynamic behavior of the robots. Computationally efficient methods for real-time assessment of force-slip characteristics are presented to provide slip setpoints for this control architecture.