Abstract
Piston cylinder is the most widely used pneumatic actuator, but its behavior is very difficult to control in rapid or precise positioning. One cause of the difficulty is the friction between piston and seal. Especially, rubber sealed cylinder has relatively high friction which makes the driving force discontinuously change. Another cause is the low response of control valves.
Recent technology makes these causes out of data, that is, labyrinth sealed cylinder and fast response proportional servo valve are available. They have low friction and rapid response respectively. This paper deals with the control performance of the servo system used by these elements. Hence the rested problems, delay and overshoot caused by the compressibility of air, are now closed up in rapid control.
To improve the performance, generalized predictive control method, which is often used as one part in the self tuning control, is adopted in this system. The method is easy to implement and it gives the control input analytically.
Controlling the system by this method and an usual feed back method respectively, it is shown that the former is effective to compensate phase lag of the system.
