Time-Optimal Control of Construction Transport Systems with Suspended Loads

The paper describes time-optimal control of construction transport systems with suspended loads, for example gantry type robots. Permissible oscillations of the loads are restricted because of safety requirements while transporting, especially at the end point. A mathematical model of such systems is presented as a pendulum attached by a suspension to a rigid robot body. The time-optimal control consists of transferring the system from an arbitrary initial state to a final state without oscillations of the loads. A control function is velocity of the body. This velocity is bounded. The length of the suspension can be changed while transporting of the load. The optimal motion modes are described. The theoretical switch lines and their approximations are obtained. An implementation of the control system for the start with stopping oscillations, motion without oscillations and the braking with stopping oscillation at the set end point is presented. Simulation results are discussed.