Abstract
For high speed positioning of pneumatic cylinders, rapid and stable acceleration and deceleration are needed. However, it has been difficult to get satisfactory response because of compressibility of air and low damping ratio of the system. Since the piston and the load are driven by the force which is produced by pressure difference between two chambers of the cylinder, higher performance can be expected by applying the control scheme based on pressure control.
In this paper, a new velocity control scheme for rapid motion of pneumatic cylinders is proposed. In many application of pneumatic cylinders, reference positions are known previously and the proper velocity pattern to reach the reference position can be designed. Thus we derive the reference pressure pattern from the velocity pattern, and construct the pressure control system such that the pressure in the cylinder chambers can follow this pressure reference. PD control scheme was adopted for the pressure control system. And the compensation for the effect of the piston motion to the pressure change was considered.
The validity of this control scheme was confirmed by the experiment in which rapid and stable acceleration and deceleration were achieved.
