Trajectory planning based on minimum input energy for the electro-hydraulic cable shovel

This paper deals with the work trajectory planning of a novel electric-hydraulic compound cable shovel. As the high-efficient mechanical equipment, the cable shovel has been widely used in the open pit mine. The excavating process of the shovel is completed by the simultaneous operation of its crowd system and hoist system. Compared with the gear or wire rope transmission, the hydraulic transmission can provide greater crowd force and more convenient overload protection. The excavating process has been modeled using shovel kinematics and dynamics, including the dynamic shovel payload and excavating resistance. On this foundation, the energy-minimum trajectory planning method by utilizing the crowd and hoist speeds described by segmental cubic polynomials, is put forward to minimize the energy consumption per unit mass. To verify the validity of the proposed method, three types of material piles with different pile angles (35°, 40°, and 45°) are compared with respect to the digging performance. Results show that the larger the pile angle is, the smaller the total energy consumption will be. The energy-minimum trajectory planning method can significantly save excavation energy as well as meet the productivity requirements.