| The feeding device is one of the key components of the steel-roll round baler,which can be used to feed the straw or forage material picked up by the pickup device into the bale chamber,It's feeding performance directly affects the working efficiency and bale density,and easy to be blocked when the feedrate is changed or the feedrate is large.Therefore,it is of great theoretical significance and practical value to study the automatic control technology of feeding mouth opening of steel-roll round baler,controling feed opening actively to prevent feeding knife roller stalling.This paper takes 9YGQ-1300 round baler as the research object.Based on the analysis of the dynamic characteristics and reliability of the feeding device,an automatic control system for the feed opening of the steel-roll round baler was designed.The main research work includes:1.Dynamic characteristics and fatigue strength analysis of feeding device when feeding: The structure and working process of the feeding machine of the round baler were analyzed.The dynamic characteristics of the knitting machine were analyzed by EDEM,the effects of feedrate,feed opening,shear modulus and length of the material on the force of the piston rod and the torque of the feed roller were studied.And then this paper analyzed the relationship between the force of the piston rod of the oil cylinder and the torque of the knife roller.The simulation results about the torque of the knife roller and the stress of the jaw plate were used as the load of the fatigue strength analysis of the feeding device based on ANSYS software,getting the allowable range of the force of the piston rod.The analysis provided the basis for the control of the cylinder piston rod.2.Design of hydraulic system for feed opening and monitoring data acquisition: The paper analyzed the jaw plate support oil circuit and changed it.Selected and installed the sensors to monitor the jaw plate support cylinder`s displacement,pressure and rotation rate of the knife roller.Constructed the hardware circuit system based on STM32 and prepared the piston rod displacement,oil pressure and rotation rate of the knife roller acquisition program.After testing,the system could control the jaw plate supporting oil cylinder action.The results showed that the transformation can meet the requirements of automatic control,and can continuously collect the displacement of oil cylinder,the oil pressure and the rotation rate of the knife roller to provide monitoring signal for automatic adjustment of the feed opening.3?The design of fuzzy controller for the automatic adjustment of the feed opening: The force and the rate of change of cylinder piston rod were regarded as the input of the fuzzy controller,the position of the cylinder piston rod was regarded as the output of the fuzzy controller.The input was divided into 7 fuzzy levels,and the output was divided into 5 fuzzy levels,and the table of fuzzy control rule was defined according to the actual working conditions.The output with different level could be got according to the table of fuzzy control rule,and automatic adjustment of feed opening could be achieved based on the position of piston rod controlled by cylinder.4?The test of load characteristics of feeding device and the automatic adjustment of the feed opening: The test and analysis of load characteristics of the feeding device was adopt under the conditions that no load and the feedrate is 2~6kg/s.The displacement of cylinder and the change rule of the oil pressure with the feedrate were got,which indicated that feeding device exists the danger clogged by straw.The test of load characteristic of feeding device and the automatic adjustment of the feed opening was implemented,which shows hydro-cylinder could achieve telescopic movement with the change of feedrate,and the fault of feeding device clogged by straw was solved.The design of automatic control system of feeding device achieved expected requirements. |
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