Sliding Mode Control of Hydraulic Power Shovel

We report an excavator driven by three links – an arm, a boom, and a swing – as representative of construction robots. Each link consists of an electrohydraulic servosystem. A problem with such excavators is the high degree of skill and comparatively long-term training required to operate it. To solve this problem, we equip the excavator with a trajectory control algorithm to control the front end. Note that the excavator's servosystems are influenced by disturbances and by nonlinear features such as asymmetrical piston geometry, initial shifts in the neural positions of servovalves and variations in moving parts inertia. For trajectory control, we apply sliding mode control using a disturbance observer in servosystems. The dynamic performance of this trajectory control is studied in experiments and results confirmed the validity of the applied method.