PD-type iterative learning control for the trajectory tracking of a pneumatic X-Y table with disturbances

In this paper, a proportional-valve controlled pneumatic X-Y table system is built to perform position tracking control experiments. The pneumatic system is subjected to external loads and parameter changes during the control. ILC (Iterative Learning Control) controllers are implemented in the experiments to show their ability to reject disturbances. The P and PD-typed updating laws with delay parameters are used respectively for the repetitive trajectory tracking control of X-Y table. Pre-saved control signals for different types of disturbances are also used to compare control performances. Experimental results show that under the disturbances, the PD-typed ILC controller is superior to the P-typed one and can effectively control the system to track the given circular trajectory.