Mechanization and Automation. Path Planning of Wheel Loader for Piled Ore Loading Operation.

A wheel loader is one of the major loading machine in surface mines. This paper describes the path planning which is a part of the research on automatic loading operation by a wheel loader. At loading operation, loader moves on V-shape path from scooping point to dumping point. A wheel loader has the articulated structure and steering is controlled by change of articulate angle. The path planning method for V-shape is proposed.Major contents of this paper are as follows;1) Kinematics of the articulate steering mechanism is analyzed. The relation between the steering angle and the curvature of path is almost liner.(2) V-shape can be composed of two straight lines and the turn path which is a combination of four pseudo clothoid paths. For given position and direction of loader at scooping point and dumping point, length of the straight lines and the shape of turn path are determined by the proposed method. Example of V-shape generation for piled ore model is shown.(3) For tracking control, the proposed control system includes the reference values generator. In path planning, control values are represented by function of moving distance. During tracking control, the reference values at each time are generated based on measured moving distance, and issued to the controller.