50 Design and Simulation on State Observer for Crane-Load System

In order to resolve the challenge that the load's swing angle and swing angle-velocity of overhead crane or gantry crane were hard to be measured directly in engineering practice, the state observer was designed by using trolley's position information, and estimate the load's swing angle and angle-velocity. The difference value between the state observer's output and the trolley-load system's output was introduced and adjusted by the observer's gain vector, then sent to the observer's input terminal. After the observer's poles were placed on complex plane, the system can estimate the swing angle and swing angle-velocity stably and quickly. Simulation study shows that the method of obtaining load's swing angle information based on state estimation is practicable, and state observer can be available online in 2s, which has strong robust property; along with rising of the pole number, state observer can be adaptive more widely in the changing of load mass and rope length; however, estimation error will change roughly when the pole number is too big; observer is more sensitive to rope length than to load mass.