Research On Dynamic Characteristics And Control Strategy Of Large-scale Liquid-air Hammer

Aiming at the big vibration shocking and the difficulty to control accurately of the largeforging equipment, and taking the liquid-air hammer system as the research object, the dynamicsperformance, the control strategy and the control technology of the large forging equipment arestudied.By analyzing the original liquid-air hammer system and the working conditions, the methodof controlling the sucking and exhausting oil process by taking the three-stage cartridge valve oflarge flow level as the actuator is proposed, and the quick response of the liquid-air hammercontrol is obtained. A hydraulic control loop system by fixed hanging weight, activecompensation for divulging is designed, the random stroke hammering of the liquid-air hammeris realized and the working safety is guaranteed. The PLC control strategy based on hammeringdata sample and fuzzy self-adaptive controller is designed, the effective hammering time of thehammer is put forward and the automatic control is realized.According to the structure of the liquid-air hammer system, the working principle and theworking conditions, the dynamics system of the liquid-air hammer system is divided into threesubsystems: the mechanical system(including the pneumatic system), the hydraulic system andthe control system. Based on the different working conditions, the dynamics performances ofeach subsystem and the parts within it are studied, the dynamics models of each subsystem fordifferent working conditions are established, the dynamics model of the total liquid-air hammersystem is set up, and the parameter determination and calculation of the models are researched.The numerical simulation of the dynamics performance of the system is studied, thedynamics performances of the mechanical system, the hydraulic system, the cartridge valve oflarge flow level and the response performance of the major parts of the control system aresimulated. The dynamics performance model of the liquid-air hammer system is set up andsimulated according to the simulation data of the subsystems and the design parameter of theliquid-air hammer system. The elements influencing the system performance are researched, andthe validity of the theoretical analysis is proved by comparing the simulation results and theactual experiment results.The control theory and method based on the fuzzy neural networks of the liquid-air hammeris studied, the conceptions of the effective hammering, the effective hammering time, the controllability and controllable field are put forward. The effective hammering samples fordifferent hammering conditions are established by the actual experiment. The transferringfunction of the control system is derived, the fuzzy neural network control laws are established.The network structure is trained by using the data of the samples, and the control laws of thefuzzy controller are determined by simulation. By the experiment, the control method is provedto be of good dynamic response performance and good stability.The research mentioned above is employed in the technical upgrade of the40t.m liquid-airhammer system, and the system turns to formal running after one-month trial production. Thesystem has been running20months so far, the working effect of the system is good, and theerror is controlled to be within0.03s, which verifies the validity of the theory research.