Research On Shearer Roller’s Position Adjustment System That Based On Electro-hydraulic Proportional Control

Coal mining machine as one of the main equipment in a fully mechanized coal faces, its roller’s automatically lifting is one of the key technologies to realize the coal mining’s intelligentialize, and has the vital significance to improve the coal production, improve production efficiency, prolongs equipment life, improve the reliability of equipment and protect the workers’safety.In a traditional coal mining machine, the roller lifting system uses a switch valve to control the hydraulic system. In the actual production, the accuracy of this control is poor, it’s hard to meet the requirements, in order to improve the existing lifting system, this paper made the following research:With the double rollers electric traction coal mining machine as an example, this paper analyzed its lifting mechanism and characteristics, the relationship between the roller’s height change of the coal mining machine and the displacement of the piston rod of the hydraulic cylinder, and analyzed the load that the roller of the coal mining machine bears deeply, then established the functional relationship between the load and the quality of the roller rocker convert to the hydraulic cylinder piston rod.This paper analyzed the hydraulic lifting mechanism system of the coal mining machine and its working characteristics, combined with the conclusions above, the mathematical model of the roller’s hydraulic lifting system was built.Simulation analysis based on the typical lifting system above were carried out by using Matlab, the results show that there is not only a big overshoot in the existing switch valve control system, and in the process of raising the switch valve needs action for many times, which reduced the service life, and it is difficult to eliminate the steady-state error of the system at the same time.In order to improve the performance of the coal mining machine’s lifting system, this paper used the electro-hydraulic proportional directional valve to replace the switch reversing valve to rebuild the lifting system. Each link of the electro-hydraulic proportional control system were analyzed, the analysis shows that the performance of the modified control system was improved. Then conducted simulation analysis in Matlab, and analyze the simulation results, it proved that control system’s dynamic performance has improved.This paper applied PID link to revise the system, and found that the PID link can get further correction as the parameters in the original system were no longer changed, which has guide meanings for the control performance’s improvement of other coal mining machine’s lifting system.Analyzed the characteristics of the fuzzy control technology, combined with nonlinear characteristics through the whole process, this paper thought that the fuzzy controller can solve the contradiction problems between the control performance and its implementation, and then built the mathematical model of the roller lifting’s fuzzy controller, using Matlab to conduct the simulation, and the results were basically the same with the analysis above.On the basis of the theory and the simulation analysis, the physical mechanisms of the coal mining machine’s lifting system were simplified, using switch valve lifting system as an example, and the prototype model of coal mining machine was built based on single chip processor as the controller hardware, fuzzy control algorithm as software, and experiments of the coal mining machine’s lifting system were conducted to verify parts of analysis of the designed control system.