Model-Based Nonlinear Trajectory Control of a Drive Chain with Hydrostatic Transmission

This paper presents an innovative nonlinear trajectory control scheme for drive chains based on a hydrostatic transmission, which are commonly used in working machines. Control-oriented modelling results in a system of four nonlinear differential equations including the actuator dynamics. It is shown that the differential pressure of the hydrostatic transmission and the angular velocity of the hydraulic motor as controlled variables represent flat control outputs. Therefore, the differential flatness of the system is exploited in combination with Ljapunov techniques to stabilize the error dynamics. Additionally, model uncertainties in the equation of motion like nonlinear friction are counteracted by an observer-based disturbance compensation. Simulation results show an excellent control performance.