Adaptive inverse dynamics control for a hydrostatic transmission with actuator uncertainties

Commercially used controllers for drive chains based on a hydrostatic transmission cannot guarantee acceptable tracking performance in the presence of uncertainty in the system dynamics, e.g., in the case of only imperfectly known actuator parameters. Hence, in this paper, an adaptive inverse dynamics control is presented that addresses this problem. The nonlinear controller consists of two main parts: an inverse dynamics controller to stabilize the tracking of desired trajectories for the difference pressure and the motor angular velocity, and an adaptation law to determine the actuator parameters online. An unknown disturbance torque is estimated using a reduced-order disturbance observer. Simulation results show that with the proposed adaptive control structure an accurate trajectory tracking is achieved despite uncertainty in the system dynamics.