Modelling and identification of a hydrostatic transmission hardware-in-the-loop simulator

Hardware-in-the-loop (HIL) simulators are effective research and development tools in many applications. A hydrostatic transmission HIL simulator, consisting of dynamic models of the transmission system and the hardware of a variable-displacement axial-piston pump and a fixed-displacement gear motor, was developed for supporting vehicle transmission system research. This paper reports the identification of the system models of the HIL simulator. A linear parameter-varying (LPV) approach was used to model the simulator, and a swept-sine technique was used for identifying the models in the frequency domain. The identified model could cover the entire operating range by adopting measured or estimated parameters at corresponding steady state operating points, which was verified through a series of step and frequency response tests at different operating points. An acceptable correlation between the experimental and simulation results was observed.