Smith-Predictor-Based Torque Control of a Rolling Diaphragm Hydrostatic Transmission

Rolling Diaphragm Hydrostatic Transmissions (RDHT) are high-performance low-cost solutions to delocalize heavy actuators away from the joints of robotic systems. Exploiting a pressure-based sensing technique, we propose here Smith-predictor-based joint torque control an RDHT-based actuation system. We also use load-cell sensor for ground truth validation. The developed feedback controller is conveniently tuned based on arbitrary pre-specified closed-loop natural frequency and damping ratio. This preserves open-loop bandwidth while removing intrinsic oscillations lightly damped highly transparent plant. Experimental tests validate proposed strategy, both in stand-alone setpoint configuration series Human-Robot-Interaction confirming significant advantages architecture.