Friction compensation for hydraulic load simulator based on improved LuGre friction model

In order to acquire better performance and minimize the trace error, the friction mechanism was analyzed. As a novel friction description, LuGre friction model and its parameter had a few limitations, because this model is only the friction description of a fixed position. Synthesized on lots of friction experience and the characteristic of hydraulic fin actuator, a changeable maximum dynamic and static friction model, which is based on LuGre model, was proposed and identified. Using structure invariance principle, a compensator was designed and verified. Experience results show that the control strategy designed by the new friction model not only works well for rejecting torque trace error, but reveals excellent ability against extraneous torque.