Infinite Impulse Response Filter Techniques for Sway Control of a Lab-Scaled Rotary Crane System

This paper presents investigations into the implementation of infinite impulse response (IIR) filter techniques in hybrid control schemes of a rotary crane system. A lab-scaled rotary crane is considered and the dynamic model of the system is derived using Euler-Lagrange formulation. To study the effectiveness of the controllers, initially a linear quadratic regulator (LQR) control is developed for horizontal angle position control of rotary crane. This is then extended to incorporate filtering techniques for anti-swaying control of the system. The Butterworth IIR low-pass and band-stop filter with different orders respectively were designed based on the properties of the system. Implementation results of the response of the rotary crane with the controllers are presented in time and frequency domains. The performances of IIR filters in hybrid control schemes are examined in terms of level of input tracking capability, swing angle reduction, and time response specifications. Finally a comparative assessment of the control techniques is discussed and presented.