A method for selecting driving system parameters of a new electric shovel's excavating mechanism with three-DOF

Driving system parameters include motor parameters and transmission ratio of the reducer. In this study, a new three-degrees-of-freedom parallel excavating mechanism of electric shovel is analysed for the selection of its driving system which consists of three sub-driving parts. Based on the principle of virtual work in the form of generalized coordinates, the dynamic model of the excavating mechanism is established to calculate the external inertia loads and force (or torque) loads. For this parallel excavating mechanism which has three sub-drives, the external inertia loads cannot be fully divided into three independent parts with respect to these three sub-driving systems. Hence, the dynamic model of the system is employed to get loads characteristic of three sub-driving systems in the excavating process. Thus, the parameters' range of the motors can be obtained and then the best transmission ratio of every reducer can be obtained.