Input Shaping for Sway Control in Gantry Cranes

Abstract

Bridge Cranes or Gantry Cranes are an essential element in the day to day activities of a manufacturing plant. The most common operation of a gantry crane is point to point transportation of payload. The use of cables for hoisting and support of payload can lead to natural swaying. This natural sway is detrimental to safe and efficient operation. Swinging degrades the speed, accuracy, and safety of transport operations. It lowers the speed of transport operations because the payload swing must die out before the payload can be safely lowered into position. The swing makes it difficult to perform alignment, fine positioning, or other accuracy driven tasks. Swing also causes safety problems because of the potential for collisions with objects or people. Under certain conditions, the problem gets more complicated when the payloads creates a double pendulum effect. This report develops a technique for improving the control of two mode double pendulum crane called input shaping. Input shaping is a control strategy that uses a series of impulses to modify the reference command to suppress unwanted vibration in a system. This report presents a method for optimizing a robust input shaper called Specified insensitivity input shapers using the knowledge of amplitude contributions of each mode to the overall response.