Research On Trajectory Control And Hydraulic-Electric Hybrid Energy Saving Method Of Mining Electric Shovel

As one of the indispensable key equipments in the open-pit mine continuous and semi-continuous mining technology system,mining shovel has the advantages of large capacity,wide operation scope,adaptability to environment and large vibration and impact load.It is widely used in stripping and loading of materials in various open-pit mines.However,the trajectory of the tip of the shovel has great randomness,and the most reasonable excavation trajectory can not be guaranteed only by manual experience,which will cause problems such as motor blockage,low full loading rate and working efficiency.On the other hand,the quality of working device of the electric shovel is very large,which needs to be raised and lowered frequently in the working process,and the upper body of the electric shovel needs to be turned forward and backward frequently.When the working device of the electric shovel drops and the upper body is braked in rotation,the gravitational potential energy and the kinetic energy of the upper body of the electric shovel will be transformed into the electric energy generated by the lifting motor and the swing motor.This part of the energy is often consumed by the braking resistance in the form of heat energy,which leads to a greater waste of energy and further increases the cooling cost of the system.In addition,in order to meet the instantaneous high-power demand in the mining process,motors are usually allocated according to the peak power required,which results in a large total installed power of the shovel,but the shovel works in a low-load state for most of the time,which results in a low efficiency of the shovel motor.Aiming at the above problems,with the support of NSFC-Shanxi Coal-based Low Carbon Joint Fund "Basic Research on High Energy Efficiency Operation of Large-scale Open-pit Mine Excavation Equipment"(U1510206),this paper studies the trajectory control method and energy-saving technology of mining shovel,and innovatively puts forward an energy-saving system of hydraulic-electric hybrid drive electric shovel.This study is of great significance to improve the trajectory control performance and operation energy efficiency of mining shovel,reduce the energy consumption and installed power of shovel,and promote the development of "intelligent" and "green" mining machinery.The specific research work in this paper is as follows:1.On the basis of considering the acceleration and deceleration process of the driving motor,the tooth tip trajectory equation,which is directly determined by the lifting speed and crowding speed,is established.The kinematics and static and dynamic loads of the shovel are analyzed,which lays a theoretical foundation for the optimization and planning of the trajectory control parameters of the shovel.2.Aiming at the lowest energy consumption per unit of material,trajectory control parameters are optimized for different working conditions.The results show that the larger the distance between vehicle and material,the smaller the material inclination angle and the higher the material level,the lower the energy consumption per unit mass of material corresponding to the optimal trajectory.3.In order to realize the precise control of the tip trajectory of the mining shovel,a parameter planning method of the tip trajectory control is proposed,and three common trajectories are used to verify the proposed planning method.The results show that the proposed planning method can accurately plan the control parameters of common mining trajectory.4.Based on the theoretical analysis model of electric shovel,a mining shovel assistant analysis platform with strong universality and high efficiency is established.5.The electro-mechanical co-simulation model of the whole mine shovel is built,and the working cycle of the shovel is simulated,which provides a reference for the study of the operation and energy consumption characteristics of the mine shovel.6.In order to reduce the installed power and energy consumption of the shovel,a hydraulic-electric hybrid drive energy-saving system of shovel is proposed,and a new mechanical-electro-hydraulic combined simulation model of the shovel is built for simulation analysis.The results show that compared with the traditional electric shovel,the hydraulic-electric hybrid drive hoisting system can reduce the peak power of the hoisting motor by about 36.7% and energy consumption by about 29.6%.The hydraulic-electric hybrid drive swing system can greatly reduce the peak power of the swing motor of electric shovel,and the swing energy consumption can be reduced by more than 90%.7.The influence of pressure and volume of accumulator on energy-saving system is analyzed.The results show that in a certain range,the reduction of peak power of the lifting motor is proportional to the initial pressure in the accumulator and inversely proportional to the volume of the accumulator.The peak power of the swing motor is inversely proportional to the initial pressure,pre-charging pressure and volume of the accumulator.