Distortion Compensation for a Robotic Hardware-In-The-Loop Contact Simulator

The robotic hardware-in-the-loop (HIL) simulator can effectively simulate the space contact dynamics on the ground. It is known that the HIL contact simulation is distorting due to the phase difference between the measured contact force and desired motion of the spacecraft. In this paper, the measured force is compensated by considering the force measurement delay, the position response error of the motion simulator, and the structural deformation of the upper platform. The delayed force measurement is first phase leaded. The force error caused by the response delay of the motion simulator is compensated by the response error and contact stiffness. The force error caused by the structural deformation of the upper platform is compensated by the deformation prediction and contact stiffness. Both simulations and experiments show that the approach can effectively reduce the distortion and improve the simulation accuracy.