Underactuated Control of Multiple Soft Pneumatic Actuators via Stable Inversion

Soft grippers, with their inherent compliance and adaptability, provide advantages for handling delicate and versatile manipulation tasks in robotics. This article presents a novel approach to the underactuated control of multiple soft actuators, focusing specifically on coordinating the soft fingers within a soft gripper and experimentally verifying the effects of actuator uncertainties. By employing a single syringe pump as the actuation mechanism, we address the challenge of coordinating multiple degrees of freedom in a compliant system. Our theoretical framework applies stable inversion theory, adapted to the unique dynamics of the underactuated soft gripper. Through meticulous mechatronic system design and controller synthesis, we demonstrate the effectiveness of this approach in achieving precise and coordinated manipulation tasks, both in simulation and experimental settings. In addition, several experiments are conducted to explore the impact of parameter-varying uncertainties in soft actuators. Our findings advance the field of soft robot control and provide practical insights into the design and control of underactuated systems, enhancing their applicability to real-world scenarios.