2021 年 14 巻 1 号 p. 28-34
In the pneumatic driving system for a soft mechanism, the control valve is the most heavy and expensive device. To realize a compact and inexpensive pneumatic driving system, it is necessary to reduce the size, weight, and cost of the control valve. In the previous study, low-cost and compact flow rate control type servo valves, that uses buckled tubes and a gate mechanism to control the flow rate in an analog way, were proposed and tested. However, in these valves, a drift of the overlap zone was observed owing to plastic deformation of the buckled tubes and lower stiffness of the valve frame. Ideally, the feedback control system using the fluidic parameter of the valve output is useful to solve this problem. However, there is no low-cost flow rate sensor in the market. In this paper, a low-cost pressure control type servo valve using buckled tubes and a gate mechanism, that consists of a low-cost pressure transducer and an on-board tiny-embedded controller, is proposed and tested. The construction and operating principle of both valves have been described. The pressure control performance of the tested valves has also been reported. As a result, it can be confirmed that the tested valve can control the output pressure according to the desired voltage. The dynamic performance of the valves has also been described.
