Optimal Tool Point Control of Hydraulically Actuated Flexible Multibody System With an Operator-in-the-Loop

The paper is on automated tool point path and velocity control of a loader crane. A two step approach is used that combines a direct computation of the optimal cylinder velocities with a general procedure that includes the different saturation phenomena encountered in a hydraulically actuated mobile machine. The two step procedure is envoked at each sampling instant during operation and returns the desired valve control signals. The first step of the procedure involves a direct computation of the optimal cylinder velocities for all possible combinations of active and non active cylinders. Among the configurations that may produce the exact velocity reference, the one requiring the least hydraulic power is chosen. Some simulation examples of the proposed procedure are shown and dynamic simulation based on the computed control signals is applied taking into account the finit bandwith of the hydraulic control valves and the flexibility of the hydraulic fluid and the mechanical structure, respectively..