Research On Anti-swing Control Of Overhead Crane Based On Linear Time Varying System Theory

Overhead cranes are widely used as an efficient means of moving heavy objects in factories, warehouses, and shipping yards. However, as its unique structure, it unavoidably causes swaying as working. At the present, most cranes are controlled manually by skilled operators. Load swing of overhead crane is controlled based on crane operator's experience using slowing the hoisting speed of overhead cranes, or waiting damping of load swing to a certain extent. The operation not only cut down the efficiency but also make against safety. So, how to reduce the swaying promptly is a representative question studied in control field home and abroad.In this thesis we consider a linearized parameter-varying model of a planar crane. Firstly, we designed a controller using the recently developed parallel differential (PD) eigenvalue assignment methodology in the invariable rope length condition. Using this theory, classical results for LTI control design carry over to the time-varying case. The main achievement of this thesis is the first implementation of a controller designed using the PD eigenevalue theory in anti-swing control of overhead cranes. And the simulation results show the validity of this method by contrast with other methods.Secondly, we consider a parameter-varying model of a planar crane in the variable rope length condition and show how a controller can be designed. That is, following the state-feedback stabilization procedure for time-varying systems proposed by Wolovich, a stabilizing state-feedback gain matrix can be computed, which make a closed-loop system equivalent, via a Lyapunov transformation, to a stable time-invariant system of assigned eigenvalues. Since Lyapunov transformation can preserve the state stability, the time-varying system is stable as well. The performance of the closed-loop system depends on the choice of the eigenvalues of the time-invariant equivalent system. The simulation results also have supported the theoretical results and have shown the proposed control method guarantees both accurate position control and prompt damping of load swing for the overhead crane, which have proved the validity of this method for anti-swing control.