Experimental and Numerical Validation on a Continuous Modulated Wave-Form Command Shaping Control Considering the Effect of Hoisting

A large body of research has been dedicated to input-shaping control techniques. Most of the research assumes constant cable length, due to the complexity of the dynamics associated with changing cable length (hoisting). Current techniques tend to split maneuvers into three consecutive stages, raising the payload from an initial point, then moving it horizontally using input-shaping, and finally lowering it to a final location. These techniques are effective, however, they involve significant time penalties. In this work, a new modulated wave-form command shaping technique is proposed to enable concurrent hoisting and travel maneuvers. The time varying ordinary differential equation of motion is derived and used to determine the parameters and frequency of the proposed shaped-command. Assuming linear hoisting, the equation is solved analytically by assuming small changes in the time varying terms. This approach results in some error which can be corrected by using pattern search optimization technique. It is shown that, the proposed method is capable of eliminating the travel and residual oscillations for different maneuvers involving linear hoisting. Performance is simulated numerically and validated experimentally on a scaled model of an overhead crane.© 2013 ASME