| Tractors have an important position in the field of agricultural mechanization.In recent years,China has vigorously supported the development of agricultural mechanization,and the number of tractors has also increased rapidly every year.With the improvement of people’s working and living standards,the comfort level of existing tractors has fallen behind the needs of drivers,and the uncomfortable vibration of tractors has caused harm to the driver’s body and mind and work efficiency.In this paper,by analyzing the feasible methods to improve the driver’s comfort of vibration damping,it is found that a reasonable design of the seat suspension damping mechanism is currently the best solution to reduce the driver’s vibration discomfort.The semi-active seat vibration damping suspension system that adjusts the damping force of the suspension can adapt to the vibration excitation in a complex operating environment.Through its own regulation and control,it can still achieve a good vibration reduction effect for the driver under the changing vibration conditions.The main research contents are as follows:(1)Complete the construction of the semi-active seat suspension platform.Considering the use of strength conditions,a suitable scissor suspension mechanism was designed and processed,and a modal analysis was conducted.According to the requirements of regulation and control,suitable control hardware was selected to build a semi-active seat suspension control system.(2)Analyze and establish the relevant model of semi-active seat suspension.Including the establishment and simulation of the road roughness model to obtain the characteristics of random road surface excitation displacement under different speeds and different levels of road surface;the establishment of a three-degree-of-freedom 1/4 seat suspension mathematical model,which is converted into a spatial state equation according to Newton’s law.(3)A quantitative test for the vibration damping performance of the suspension mechanism and a vibration data acquisition test for the chassis of the tractor cab were carried out.The input current corresponding to the magneto-rheological damper when the vibration damping effect of the seat suspension is the best under three typical vibration conditions is obtained,which is used as the basis for the design of the control system;the vibration acceleration data of the chassis of the tractor cab is collected and analyzed to obtain the seat The amplitude range of the chair suspension subjected to vibration excitation in the field is mainly concentrated in 3-20 mm.(4)Research on seat suspension current control algorithm based on fuzzy adaptive PID.A fuzzy adaptive PID algorithm combining PID control and fuzzy control features is designed to regulate the working current of the seat suspension.Use MATLAB’s Simulink platform to debug and simulate the fuzzy adaptive PID controller.The simulation response curve shows that the fuzzy adaptive PID controller has faster response,shorter adjustment time and more stability than the conventional PID controller,which fully meets the needs of tractor seat suspension.(5)In the bench test experiment of the semi-active seat suspension designed and researched in this paper,the input of the seat suspension was 3mm,5mm,and 8mm,and the amplitude was reduced to 0.5 after damping the suspension.mm,1.5mm,2.5mm.The results show that the seat suspension can adjust the output damping force in real time,which meets the needs of tractor drivers for vibration reduction comfort in complex operating environments. |
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