Improvement of Low-cost Wearable Servo Valve Using Buckled Tube

In wearable pneumatic driving system, the small-sized and lightweight control valve and wearable actuator are important. Mostly, the total cost of control system depends on the cost of valves, because an industrial servo valve is very complex and expensive compared with a wearable actuator. The purpose of our study is to develop a small-sized and low-cost control valve that can be safe enough to mount on the human body. In our previous study, the low-cost servo valve using buckled tube was proposed and tested. However, the valve has relatively larger hysteresis in a relation between the motor rational angle and output flow rate. In this paper, the improved servo valve with less hysteresis characteristics of output flow rate will be proposed and tested. In addition, the configuration of the buckled tube on the valve is redesigned in order to reduce overlap of the valve. As a result, the position control performance of the rubber artificial muscle using the valve could be improved.