Dynamic Control of Soft Robotic Arm: A Simulation Study

In this article, the control problem of one segment pneumatically actuated soft robotic arm is investigated in detail. To date, extensive prior work has been done in soft robotics kinematics and dynamics modeling. Proper controller designs can complement the modeling work since they are able to compensate the effects that have not been considered in the modeling, such as the model uncertainties, system parameter identification error, hysteresis, external forces, disturbances, etc. In this letter, we explored different control approaches (kinematic control, PD+feedback linearization, passivity control, adaptive passivity control) and summarized the advantages and disadvantages of each controller. We further investigated the robot control problem in the practical scenarios when the sensor noise exists, actuator velocity measurement is not available, the hysteresis effect is non-neglectable, as well as the existence of external force. Our simulation results indicated that the adaptive passivity control with sigma modification terms, along with a high-gain observer presents a better performance in comparison with other approaches. Although this paper mainly presented the simulation results of various controllers, the work here will pave the way for practical implementation of soft robot control.