Development of Bucket Scooping Mechanism for Analysis of Reaction Force Against Rock Piles

A bucket control mechanism is developed for the simulation of rock pile scooping by wheel loaders. By measuring the reaction forces from the scooped rock pile by a six axis force sensor installed into this mechanism, the reaction force model can be obtained and its parameters are identified. By using the obtained model for controlling actual wheel loaders, efficient scooping can be expected. In this paper, the kinematic and static characteristics of the bell-crank mechanism are analyzed and an experimental system is designed and built up using the analysis results. Then, a high gain servo control system is designed by using disturbance observers. The acquisition of the accurate rock pile model is tried by several experiments. Then some control algorithms based on feedback signals from the force sensor are proposed and their control performances are evaluated.