| As heavy mining trucks run for a long time and work in harsh environment,they are required to run reliably and stably,so the vibration damping performance of vehicles is required to be higher.The suspension system is an important part of the vehicle,which plays a key role in the vibration damping performance of the whole vehicle.The traditional hydro-pneumatic suspension system is difficult to provide better ride comfort.Therefore,based on the 220-ton mining dump truck,a semi-active hydropneumatic suspension based on fuzzy PID control is proposed in this thesis,and the mathematical model of the semi-active hydro-pneumatic suspension is established and the characteristics are analyzed.Then the multi-body dynamics model and fuzzy PID controller of mine dump truck are established.Finally,the ride comfort simulation analysis on different complex road surfaces is carried out.The main research contents of this thesis are as follows:(1)On the basis of the analysis of the working principle and characteristics of the hydro-pneumatic suspension,the mathematical models of the damping force and the elastic force of the mining dump truck suspension in the compression stroke and the tensile stroke are derived.The simulation model of stiffness and damping characteristics was established by Simulink software,and the curve of stiffness and damping characteristics was drawn by the simulation data.The detailed influence of the diameter of the damping hole on the damping characteristics was discussed,and the diameter of the damping hole of the front and rear suspension was selected as 9mm.The influence of the current of the solenoid proportional valve with the damping hole size of 9mm on the suspension characteristics is analyzed.Through analysis,it can be seen that there is a positive correlation between damping force and current.The natural frequency and equivalent damping ratio of suspension are calculated to ensure that the design parameters meet the requirements.(2)Firstly,the three-dimensional model of each system of the 220-ton mining dump truck is built to simplify it reasonably.Then the 3D model is imported into ADAMS,and corresponding constraints and drives are given,and the whole vehicle dynamics model of the mining dump truck is established.Class D and Class E random pavement spectra were established by MATLAB and imported into ADAMS to form a3 D pavement model.Finally,the multi-body dynamics model of mining dump truck was established.(3)Based on the structural principle,advantages and disadvantages of PID control and fuzzy control,the framework and parameters of fuzzy PID control are studied,and the fuzzy PID control system model is set up with the help of MATLAB.The Simulink simulation model of mining dump truck is built,and the performance of fuzzy PID controller is tested under the excitation of random road surface and step road surface,so as to ensure that the vibration reduction performance meets the requirements.(4)Combined with ADAMS physical model and MATLAB control system model,the co-simulation was carried out,and the root-mean-square value of the total weighted acceleration at the seat of the mining dump truck was taken as the evaluation index of ride comfort.The ride comfort simulation analysis of fuzzy and fuzzy PID semi-active hydro-pneumatic suspension on class D random road surface and class E random road surface as well as under no-load and full-load conditions is carried out.The simulation results show that the ride comfort of mining dump truck varies greatly with different vehicle speeds,and the ride comfort of no-load and full-load conditions are very different.The damping performance of semi-active suspension is better than that of passive suspension.Compared with fuzzy semi-active hydro-pneumatic suspension,the mine dump truck with fuzzy PID semi-active hydro-pneumatic suspension has better ride comfort.The thesis has 53 figures,24 tables,and 110 references. |
PDF Full Text Request