An injecting method of physical damping to haptic interfaces based on FPGA

In this paper, an injecting method of physical damping to haptic interfaces is proposed. For injecting adjustable physical damping, time-domain passivity controller is implemented in hardware level with FPGA. Noise free velocity signal can be estimated with T-method. Instead of force command from the virtual environment, directly measured current signal with Hall sensor is used for calculating more accurate energy flow. The entire time-domain passivity control scheme is implemented with several different control routines inside FPGA, and through this hardware implementation, noisy behavior of the conventional software based time-domain passivity controller can be significantly removed.