Frequency Modulation Input Shaping Control of Double Pendulum Overhead Cranes

Abstract

Traditionally, multimode input shaping controllers are tuned to systems' frequencies. This work suggests an alternative approach. A frequencymodulation (FM) input shaping technique is developed to tune the resonant frequencies of a system to a set of frequencies that can be eliminated by a singlemode primary input shaper. Most of the current input shaping techniques can be used as primary input shapers for the FM input shaping technique. Virtual feedback is used to modulate the closedloop frequencies of a simulated doublependulum model of an overhead crane to the point where the closedloop second mode frequency becomes an oddmultiple of the closedloop first mode frequency, which is the necessary condition for a satisfactory performance of most singlemode input shapers. The primary input shaper is based on the first mode frequency of the closedloop system model. The input commands to the plant of the virtual feedback system are then used to drive the physical doublependulum. Simulations results, using primary zerovibration (ZV) and zerovibrationderivative (ZVD) input shapers, are presented. The performance is validated experimentally on a scaled model of a doublependulum overhead crane.