油圧ショベルのブーム,アーム系の高精度軌跡制御

概要

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In the control of a hydraulic excavator using hydraulic actuators, it is difficult to obtain desired trajectory or response due to its nonlinearity, for instance, variation of the moment of inertia, the unsymmetrical effect of single rod cylinders, interference between axes and unknown external forces caused by excavating resistance. In this study, to begin with, we construct a servo system as a first step for realizing autonomous control of hydraulic excavators. We propose applying a disturbance compensation robust control system using a disturbance observer for the system to which several disturbances including parameter change are added. Using this control method, we realize improvement of robustness of a system without increasing loop gain by compensating its nonlinearity. For experiments, a Hitachi Mini Excavator EX40 is reconstructed so that the boom and the arm are driven by servovalves. Circular trajectory of the end of the arm in addition to step response of the boom and the arm are experimentally obtained. Also, the results obtained using a disturbance observer are compared with those obtained using only position feedback. As a result, it is experimentally shown that this control method can improve positioning accuracy and trajectory tracking performance required in surface excavating operation.
社団法人日本機械学会の論文
1996-01-25