tailieunhanh - PID control for a pneumatic servo system

This paper examines the position control ability of a pneumatic cylinder in pneumatic servo system using PID control method. A pneumatic servo system including a pneumatic cylinder and 02 proportional flow control valves is firstly proposed. | Journal of Science Technology 138 2019 012-017 PID Control for a Pneumatic Servo System Tran Xuan Bo Hanoi University of Science and Technology - No. 1 Dai Co Viet Str. Hai Ba Trung Ha Noi Viet Nam Received January 25 2019 Accepted November 28 2019 Abstract This paper examines the position control ability of a pneumatic cylinder in pneumatic servo system using PID control method. A pneumatic servo system including a pneumatic cylinder and 02 proportional flow control valves is firstly proposed. The system is then modeled by dynamic equations with consideration of the valve characteristics and of friction in the pneumatic cylinder. Proportional- Integral- Derivative controller PID is applied to control the cylinder position. Effects of the external load and the source pressure to the control ability of the PID controller are considered. Simulation and experimental results show that the PID controller gives good control performances under different operating conditions of the external load and the air source pressure. Keywords Pneumatic servo system PID control Pneumatic cylinder 1. Introduction Pneumatic servo systems are widely applied in many industrial applications because they are cheap lightweight clean easy to assemble and create a good force weight ratio. However it is very difficult to achieve high-precision position control using pneumatic cylinders due to the compressive properties of the air the nonlinearity of the servo valve or proportional valve and nonlinear friction properties existing between the contact surfaces in the pneumatic cylinders. In order to improve the position control performance of pneumatic servo systems many control methods have been proposed. In early applications controllers were developed by linearization of the system model around the mid-stroke position 1 or other operating points 2 . Richardson et al. used self-tuning control for a low-friction pneumatic actuator under the influence of gravity 3 . In early applications of .