Real-Time Hybrid PID/ILC Control of Two-Link Flexible Manipulators

This paper investigates the development of a hybrid proportional-integral-derivative (PID) with iterative learning control (ILC) for input tracking and vibration control of a two-link flexible manipulator (TLFM). The TLFM was modelled using Lagrange's formalism and assumed mode method (AMM). Three part apparatus was designed and implemented: FLEXISIM - TLFM mathematical model; FLEXIBOT: a real-world TLFM; and FLEXICON software: applications of PID control and hybrid PID with ILC schemes to the real-world TLFM. Each of the control schemes was investigated for tracking of sinusoidal waves and vibration suppression. It was found that the PID-based controller was incapable of acceptable control of the FLEXIBOT. The PID-ILC control scheme achieved acceptable tracking, with the former demonstrating better stability and energy efficiency. The effect of payload variations on the performance of the proposed controller is also studied. Experimental results show the effectiveness and robustness of the proposed controller.