Theoretical analysis of surplus torque in electro-hydraulic load simulator

There is mutual interference between force system and steering gear system when the electro-hydraulic load simulator is working. This interference causes large surplus torque in the loading system, which affects the loading accuracy and the dynamic performance greatly. In this paper, in-depth theoretical analysis of the electro-hydraulic load simulator has been presented, the mathematical model of surplus torque has been built up, all kinds of factors which affect the surplus torque have been discussed, simulation and experiments have been made to testify the results. It can be concluded that the velocity disturbance from steering gear acting on the loading system is the key factor which brings about the surplus torque. Proper selection of load system's structural parameters, such as load stiffness, motor displacement and effective volume, is crucial to the high performance electro-hydraulic load simulator's implementation.