Due to the dynamic response delay (DRD) of the lower motion simulator in the system, the HIL contact simulation becomes divergent. In this chapter, a distortion compensation control method for the simulation divergence caused by the dynamic response delay of the lower motion simulator is proposed. In some cases, the dynamic response of the lower motion simulator is time-varying and unknown. This motivates to develop the model-free compensation method. It compensates the contact force from the real-time response error of the lower motion simulator and the real-time identified contact stiffness and damping. Simulations and experiments are used to verify the effectiveness of the proposed distortion compensation control method.