Recently, the ratio of the Japanese elderly became more than 26 % in 2020. Under these circumstances, various assisting and rehabilitation devices to help welfare work for the elderly and disabled using pneumatic soft actuators have been actively developed. A pneumatic soft actuator is useful for, not only power assisted system but also a rehabilitation device. In the previous study, the Extension type Flexible Pneumatic Actuators (we call it “EFPA” for short) that could extend 2.5 times of its original length was proposed and tested. W. Tian developed the Tetra hedral-shaped Soft Actuator (we call it “TSA” for short) for wrist rehabilitation. Usually, a pneumatic actuator was often used for wearable and rehabilitation devices because it has an advantage of compliance based on air compressibility. Especially, a pneumatic soft actuator is more suitable because it has more advantages such as lighter-weight and more compliance based on flexibility. Based on this concept, the mobile robot using six TFAs for core training and amusement was also proposed and tested. The mobile robot that consists of six TSAs was proposed and tested. The control system that consists of the tested robot and 18 on/off valves was also proposed and tested. The sequential driving pattern for moving forward and rotating in clock-wise and counter clock-wise was investigated. As a result, it can be confirmed that the tested robot can move toward six directions and rotate toward both clock-wise and counter clockwise. In the next step, to realize precise attitude control of the robot, it is necessary to develop the attitude measuring sensor to recognize bending angle and extension length of leg (TSA). In this paper, the construction and operating principle of the tested sensor that consists of a hall sensor and a ring-shaped magnet were described. As a simpli fication of the driving system for leg (TSA), the simple control system using the tested sensor, an embedded controller and 4 on/off valves was also described. As a result, the attitude control of the TSA by feedback of the tested sensor signal can be realized.
