Development of A New Soft Robotic Module Using Compressed Air and Shape Memory Alloys

摘要

Soft robots are attractive devices for medical tools. Rehabilitation actuators, endoscopy or colonoscopy devices and noninvasive catheters are the candidates which could be more effective as a soft robot. One of the most straightforward and inexpensive way to actuate soft robots is using compressed air. This light and powerful energy source supports a good response time. However, air compressibility and flexibility of soft robots tends to significant challenges in the precise position control of the robot. Shape memory alloys (SMAs) are other types of actuators with unique characteristics. Simple actuation, being lightweight and high force-to-weight ratio are suitable properties of SMA for such application. In this paper, a fiber-reinforced prototype of a soft robotic module made of silicone rubber with a semicircular cross-section is developed. By employing shape memory alloy springs on the body of the soft robotic module, precise control of bending in the vertical plane is achieved. In addition, the degree of freedom in the horizontal surplus plane is increased. For position control of the robot in the workspace, a simple closed loop controller is used along with a couple of cameras to measure the angular displacement of the robot in both vertical and horizontal planes. Based on the obtained results, it has been demonstrated that more accurate controllability and a larger workspace are provided using the shape memory alloy springs.