Development of a Poppet-Type Pneumatic Servo Valve

Abstract

In pneumatic positioning and force-control systems, spool-type servo valves are widely used for obtaining quick responses and precise control. However, air leakage from these valves results in increased energy consumption. To address this problem, we developed a three-port poppet-type servo valve to reduce air leakage. The developed valve consists of a camshaft, two orifices, two metal balls, and a housing with two flow channels. The metal ball is pushed by fluid, and spring force closes the orifice. The port opens when the cam rotates and pushes the ball. The cam shape and orifice size were designed to provide the desired flow rate. The specifications of the DC motor for rotating the camshaft were determined considering the fluid force on the ball. Static and dynamic characteristics of the valve were measured. We experimentally confirmed that air leakage was 0.1 L/min or less. The ratio of air leakage to maximum flow rate was only 0.37%. Dynamic characteristic measurements showed that the valve had a bandwidth of 30 Hz. The effectiveness of the valve was demonstrated through experiments involving pressure and position control.

Improving Energy Efficiency of Flexible Pneumatic Systems

“…An important advantage of PWM control is lower consumption of compressed air. The air leakage reduction for improving the energy efficiency of the pneumatic system is proposed in [24,25]. Additionally, a number of authors have worked on improving the energy efficiency of pneumatic actuators utilizing circuits that were more complex, for example, a dual pressure supply [26] and air expansion energy [27].…”

Reuse of Exhausted Air from Multi-Actuator Pneumatic Control Systems

“…In most factories, only one part of the total compressed air is efficiently used [1][2][3][4]. This creates the need to pay close attention to its proper use and increase the energy efficiency of compressed air systems [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. In reference [6], three possible ways to improve the energy efficiency of a compressed air system were identified: preventing energy losses [8], decreasing energy consumption [5], and reducing energy waste [9].…”

Special Feature on Advanced Mobile Robotics

“…Sun et al [61] designed a novel robot to assist human astronauts in a space station, and demonstrated its walking, rolling and sliding motion. For pneumatic positioning and force-control systems, Kanno et al [62] proposed a three-port poppet-type servo valve to reduce air leakage of the spool-type servo valves. It is effective even in experiments with pressure and position control.…”