Servo-hydraulic positioning system for the ALPINE MINER

The structural elasticity and the oil compliance cannot be neglected in servo-hydraulic systems, which are subjected to heavy loads, for example, the cutting boom of a mining machine. If a conventional P, PD or PT1 controller is used for position control, this has the effect of decreasing the natural damping of the system. An increased tendency for oscillations will occur with the attempt to get the optimal position accuracy. As a solution, an acceleration feedback loop may be used to achieve a better controller performance. An analysis of the acceleration feedback method is presented which can be used to design the controller. Further, a practical application to the servo-hydraulic adjustment system of a mining machine is shown. The machine was equipped with a hydraulic positioning system for the vertical pivoting motion. One aim of the project was to develop an active stabilization system for the cutting boom to improve the cutting process.