Improvement of Bending Movements in a Pneumatically Actuated Smart Robotic Muscle Using Shape Memory Alloy

Soft robots are usable devices in special applications such as clinical instruments in endoscopy, colonoscopy, catheters or a part of a soft gripper. Nonetheless, accurate control of soft robotic modules is a significant difficulty that researchers in this field have been addressed. Using compressed air to actuate soft robots may be the most accessible and cost-effective method. This quick and potent energy source tends to a short response time. But the air compressibility and flexibility of soft robots provide significant challenges in precise position control. Shape Memory Alloys (SMAs) are another type of actuator with unique properties such as simple actuation, light weight, and a high power-to-weight ratio, among a longer response time and cooling difficulties. The main objective of this paper is to apply shape memory alloy to improve the bending movements of a pneumatically actuated soft robotic module. A soft fiber-reinforced silicone rubber of a robotic muscle with a half-circle cross-section is manufactured. In outer body of the module a shape memory alloy spring is mounted to provide fine motions in the module. An empirical feedback controller is used in conjunction with a camera to measure angular displacement in the vertical plane (XZ) to control the robot's orientation in its workspace. According to the acquired results, it has been demonstrated that combining air pressure actuation and shape memory alloy springs, tends to more precise position control in the XZ plane.

Keywords:

Soft Robots , Actuator , Compressed Air , Shape Memory Alloys.