The traditional electro- pneumatic PWM (pulse width modulation) proportional valve driven by electro-mechanical converter of electromagnet has the disadvantages of slow response and poor control precision etc. To solve this problem, a novel piezoelectric electro- pneumatic PWM proportional valve driven by the electro-mechanical converter of piezoelectric stack was presented, where its displacement was amplified by the amplification mechanism based on flexure hinges. Then the mathematical model of PWM proportional valve was set up. On this basis, a prototype was fabricated and its related test was researched. The effect of PWM carrier frequency, proportional control coefficient and flow load on the valve performance was analyzed. And the compound control method combined with pressure feedback, P control and PWM was applied to enhance the steady precision of valve. The experiments indicate that the valve has fast response and high steady precision, with good industrial application prospect.%针对采用电磁铁为电-机械转换器的传统电-气脉宽调制(PWM)比例阀存在响应速度慢、稳态精度差等缺点,提出了一种以压电叠堆结合弹性铰链位移放大机构为电-机械转换器的新型压电式PWM比例压力阀的总体结构方案,并建立其数学模型;研制了试验样机并进行了相关的试验研究,分析了PWM载波频率、比例控制系数和流量负载对阀性能的影响;采用比例P控制+压力反馈+PWM的复合控制方法有效提高了阀压力稳态精度.试验表明,该阀具有响应速度快和稳态精度高等特点,具有良好的工业应用前景.
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