Lumped Parameter Mass Flow Rate and Pressure Control Characteristics Model for High-Speed Pneumatic PWM on/off Valve

• Published in: 东华大学学报（英文版） Vol. 31; no. 3; pp. 293 - 303
• Main Author: 向忠 胡旭东 刘昊 汝晶炜
• Format: Journal Article
• Language: English
• Published: Faculty of Mechanical Engineering & Automation, Zhejiang Sci-Tech University, Hangzhou 310018, China 30.06.2014; State Key Laboratory of Fluid Power Transmission and Control, Zhejiang University, Hangzhou 310027, China%Faculty of Mechanical Engineering & Automation, Zhejiang Sci-Tech University, Hangzhou 310018, China%State Key Laboratory of Fluid Power Transmission and Control, Zhejiang University, Hangzhou 310027, China
• Subjects: pressure characteristic; pneumatic on/off valve; mass flow rate; pulse width modulation (PWM); lumped parameter model
• ISSN: 1672-5220

Aiming at solving the problem of strong coupling characteristic of the key parameters of high-speed pneumatic pulse width modulation（ PWM） on / off valve, a general lumped parameter mathematical model based on the valves time periods was well developed. With this model,the mass flow rate and dynamic pressure characteristics of constant volumes controlled by high-speed pneumatic PWM on /off valves was well described. A variable flow rate coefficient model was proposed to substitute for the constant one used in most of the prior works to investigate PWM on /off valves＇ dynamical pressure response, and a formula for disclosing the inherent relationship among the PWM command signal,static mass flow rate,and sonic conductance of the valve was newly derived.Finally,an extensive set of analytical experimental comparisons were implemented to verify the validity of the proposed mathematica model. With the proposed model, PWM on /off valves＇ characteristics,such as mass flow rate,step pressure response of the valve control system,mean pressure and ripple amplitude,not only in the linear range,but also in the nonlinear range can be wel predicted; Good agreement between measured and calculated results was obtained,which proved that the model is helpful for designing a control strategy in a closed loop control system.