Determining the parameters of the trajectory of the bucket of mining quarries excavators

The bucket positioning of the excavator in three-dimensions (3-D) is the precondition of the robotic excavator starting automatized works. The electric excavator is one of the most widely used machinery in the mining industry, mainly due to its versatility and portability. Among the tasks performed by the excavator, there is a significant number of repetitive movements associated with moving the bucket to the unloading point and back to the face. Using automated functions to perform such repetitive tasks will not only significantly increase overall productivity, but also reduce energy consumption. This research is carried out to create a method of coordinate control of electric drives of the boom, dipper stick, and bucket of an electric excavator to perform accurate and efficient work. On the basis of the kinematic analysis of the excavator’s attachment system, the trajectory of the end of the working body can be determined from the point of view of the coordinated movement of the electric drives of the main mechanisms of the excavator. Thus, the complex algorithm of the excavator bucket 3-D position control can be carried out by coordinated control of the movement of three separate electric drives. This coordinate control algorithm was tested on the example of the EKG-8I excavator, and the results of the verification showed that this developed control method can satisfactorily perform the function of automatic control of the bucket position in three-dimensional space. Optimization of control will be further carried out based on the analysis of the energy efficiency of various possible trajectories.

Research on Constant Power Control Strategy of Pure Electric Excavator

Electric construction machinery can achieve zero emissions and be pollution free in the process of construction. In an electric excavator, to make full use of the output power of the power source, the output power of the electric motor (EM) should be absorbed by a hydraulic pump on the most attainable level. Therefore, constant power control is generally employed to achieve power matching between the power source and hydraulic pump. In this paper, considering the shortcomings of a single constant power point in a traditional load sensing system of electric construction machinery, combining the discharge characteristics of the li-ion battery and the overload capability of EM, a piecewise constant power control strategy is proposed to realize the organic unity of power and safety for a novel electric construction machinery power train system. The control strategy is verified by simulations and experiments. The results show that the system can not only satisfy the large power output but also ensure the normal and stable operation of the system when the electric excavator meets the heavy load through the piecewise constant power control. The proposed control strategy improves the dynamic performance of the system on the basis of ensuring the safety of the system.

The Influence of Voltage Quality on Asynchronous Motor Performance of EKG Excavator in Open Pit Mines – Vinacomin

At present, in open-pit mining, the main and most important electrical load is the electric excavator, and currently using a variety of EKG excavators. 6kV electrical network in open pit mining has the characteristics such as long outgoing lines, use high-powered equipment, multiple branches, and increasing use of power electronics on the grid, this reduces the quality of the power supplied to the excavators EKG, resulting in an increase in power losses thereby greatly affecting the performance of the excavators. Previous studies on the quality of the power supplied to the excavator often only mentioned voltage deviations, in addition to this factor, the performance of the excavator is also greatly affected by nonsinusoidal voltage waveforms of the excavator power supply. This paper analyzes the influence of the nonsinusoidal of voltage on the power loss of electric motors used in EKG electric excavators in open pit mining based on the method of electromagnetic analysis and verification on simulation software.