Development of low-cost wire type linear potentiometer for flexible spherical actuator

The rehabilitation devices help the elderly who was injured temporally to recover their physical ability for keeping Quality of Life (QOL). This study aims at developing a potable rehabilitation device which can be safe to use while holding it with human hands. In the previous study, the novel flexible pneumatic cylinder that can be used even if it is deformed has been developed. The flexible spherical actuator using two ring-shaped flexible pneumatic cylinders was proposed and tested as a portable rehabilitation device. The attitude control system using a tiny embedded controller, four small-sized quasi-servo valves and two accelerometers was also proposed and constructed. In the next step, it is necessary to recognize the relative position between both stages to prevent both hands to contact each other for safety. In this paper, two types of flexible displacement sensors were proposed and tested. One is a flexible pneumatic cylinder with wire-type linear encoder. Another is the cylinder with a wire-type linear potentiometer. In both sensors, the compact sealing mechanism in the cylinder was also proposed. In addition, the measuring system for the linear encoder and the position control system using the flexible pneumatic cylinder with built-in flexible displacement sensor using embedded controllers were proposed and tested. As a result, it is confirmed that the tested sensor can measure the displacement of the flexible cylinder and the position control using the cylinder with built-in sensor can be realized.