Nullspace Adaptive Velocity Controller for Ground Vehicles: Theory and Experimental Evaluation

We report a novel stable Model-Based Adaptive Velocity Tracking Controller (AVTC) for ground vehicles capable of asymptotically exactly tracking longitudinal and yaw reference velocities and simultaneously adaptively identifying unknown plant parameters and actuator parameters. The reported AVTC is developed for velocity control of the commonly accepted three degree-of-freedom second-order dynamic “bicycle” model for ground vehicles. A Lyapunov analysis shows asymptotic stability of the velocity tracking error in longitudinal and yaw velocities, boundedness of all signals, and convergence of the adaptive parameter estimates. A performance evaluation of the proposed AVTC is reported including numerical simulation evaluation and experimental evaluation that corroborates the analytical predictions of stability and tracking, and compares its performance to its non-adaptive counterpart and two alternative controllers. AVTC only requires body-frame velocities and control input signals, and robustly detects, quantitatively identifies, and compensates dynamically in real-time for faults arising from changes to plant, actuator, and environmental parameters during operations.