Design of Linear Parameter Varying Controller for Hydrostatic Transmission System (HST)

Hydrostatic Transmission system (HST), is extensively used in mobile working machines, off-road vehicles, agricultural and construction machines such as loaders and tractors. In this system, important parameters such as hydromotor and hydropump speeds and their angles, and also pressure difference are constantly changing with time. Therefore, the issue of regulation and control of these parameters has become an important issue among researchers in this field. In this paper, first, the nonlinear system model is converted to polytopic LPV form and then a linear parameter varying feedback controller based on Lyapunov method is designed using LMI techniques. Finally, after finding the appropriate feedback controller gain, the controller is applied on the nonlinear system. The simulation results show the effectiveness of this proposed method in controlling system states.