| Die forging hammer is the most widely used and most applicable forging equipment in the forging industry.It has the advantages of fast strike speed,good formability and good metal fluidity of forgings,and is widely used in the mechanical manufacturing industry.The traditional hydraulic system of forging hammer is complex,the circuit connection is inconvenient,and it contains a strike valve.The system has high heating,high energy consumption and low efficiency.In this paper,direct-drive electro-hydraulic servo drive technology is applied to die forging hammer.The positioning,speed adjustment and energy setting of the hammer are all carried out by servo motor,which has excellent controllability and improves the energy efficiency and life of the hammer.Firstly,the hydraulic system schematic diagram of direct drive electro-hydraulic servo control die forging hammer is designed,and its working principle and advantages are analyzed.By studying the energy control principle of new die forging hammer,the indirect energy storage conversion control method and conversion principle are proposed.Then the power matching of the system and the calculation and selection of the main component parameters are carried out.On the basis of the analysis of the direct drive electro-hydraulic servo die forging hammer system,the impact energy of the hammer is modeled by analytical method,and the simulation model is established by Simulink.The energy simulation relationship between the impact energy and the motor speed is obtained intuitively,and the more accurate energy control is realized.The mathematical models of AC servo motor and pump-controlled cylinder system are established.Based on the two models,the mathematical models of direct drive electro-hydraulic servo die forging hammer control system are established.The simulation model of the system is built on Simulink platform.The dynamic characteristics of the system are simulated and analyzed.The relative stability of the system is proved by the amplitude margin and phase margin in Bode diagram.It can be seen from the curve that the dynamic response time of the pump control system can meet the working condition of the die forging hammer.The simulation results verify the feasibility of the control system.The AC servo motor model and hydraulic system model are established onAMESim.The whole process of hammer striking and lifting is simulated and analyzed.The system performance curve,pump output flow curve and servo motor speed curve are obtained.From the simulation results,it can be seen that the servo motor can effectively control the flow rate and realize the speed control by controlling the servo motor.Finally,a wavelet neural network PID control algorithm is proposed to realize closed-loop control of pressure and speed of direct-drive electro-hydraulic servo die forging hammer.A joint simulation model of AMESim and Simulink is built.The hardware-in-the-loop simulation experiment of the control system is designed.The cSPACE system based on the DSP control card is used as the control prototype.The simulation and experimental results verify the correctness of the scheme. |
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