Bilateral Control of Nonlinear Pneumatic Teleoperation System With Solenoid Valves

In past research on the control of pneumatic actuators, typically proportional servovalves have been used for achieving high-performance control of the mass flow rate. In this brief, we instead use fast-switching ON/OFF valves due to their distinct advantages in terms of low cost and small size. Accurate control of pneumatic actuators with ON/OFF solenoid valves is a challenge since the system dynamics is both discrete input and highly nonlinear. In this brief, we apply a hybrid control algorithm to a pneumatic actuator with ON/OFF valves. Such a control approach is developed for choosing the best control vector at each sample time to track the reference state (i.e., desired force) in the inner force control loop within a bilateral teleoperation system. Experimental results show that good teleoperation transparency is achieved despite all the obstacles such as discrete input and nonlinear behavior of the pneumatic-actuated teleoperation system.