Transient response investigation for open and regenerative connections of a pneumatic cylinder

Abstract

Pneumatic actuation systems have long been a topic of debate in the fields of automation and control. These systems rely on pressurized vessels as their primary energy source, and the dimensions of these vessels are critical to specific applications. Notably, the regenerative cycle (a pneumatic configuration that interconnects dual-action cylinder chambers) offers a means to reduce gas consumption from the reservoir when compared to the open cycle. However, it is essential to recognize that this efficiency gain comes at the cost of altered cylinder response characteristics. In this paper, an analytical model for simulating the transient response of a pneumatic cylinder during expansion for both open and regenerative cycles was presented. A MATLAB Simulink model was developed based on fundamental mathematical equations, incorporating relevant assumptions. Specifically, non-linear effects in the cylinder dynamics, working gas properties, and frictional behavior were explained. Additionally, an experimental test rig was constructed to validate the mathematical model. The results showed a strong correlation between the simulation and experimental data. For a supply pressure of 2 bar, the piston’s expansion stroke time is 94.6 ms for the regenerative cycle and 32.6 ms for the open cycle, indicating that the regenerative cycle slows the response by 65.5% compared to the open cycle.