| With the development of modern automobile structure lightweight and the improvement of road conditions,consumers’ expectation of vehicle comfort is rising,and they are more and more concerned about the vibration problems of automobile engines.Compared with passive mounts,magnetorheological semi-active mounts have received special attention from researchers at home and abroad because of their typical characteristics of continuously adjustable damping and suitable control strategies to improve their vibration isolation performance.In order to investigate the effectiveness of magnetorheological mounts,this dissertation designed the overall control scheme of magnetorheological mounts,completed the study of their dynamic characteristics,established the simulation model of two-degree-of-freedom automotive engine mounts vibration damping system,and compared and analyzed the vibration damping effects of passive control,traditional PID control strategy and the self-anti-disturbance control strategy based on whale optimization algorithm.The main research contents were:1.The overall control scheme of the magnetorheological suspension system was studied.The basic theory of Magnetorheological fluid was discussed,including the rheological properties,working mode and design criteria.The composition structure and working principle of extrusion mode magnetorheological mounts were discussed.The overall control scheme of the magnetorheological semi-active suspension damping system for two-degree-of-freedom automobile engines based on quarter models was designed.A forward and inverse model of the Coulomb damping force was derived.2.The dynamic characteristics of the magnetorheological suspension were simulated.A magnetorheological structure based on squeeze mode rheological suspension was designed based on electromagnetic field theory.Verified the reasonableness by Maxwell FEA.The variation law of the magnetic induction intensity response current was introduced.Established a magnetorheological suspension dynamic model.The performance curves of magnetorheological suspension output damping force and the performance curves of dynamic stiffness and hysteresis angle were obtained by using MATLAB/Simulink simulation analysis at different currents and different excitation frequencies.3.The damping control system of the magnetorheological suspension for automotive engines has been modeled.Using passive mounts as an entry point,a simulation model of a two-degree-of-freedom engine mounts control system with a four-cylinder engine as the vibration source was established.Static and dynamic analyses of the control system were carried out.Verified its stability and energy control observability.The transient response of the control system was also tested with a step signal as input.4.WOA-ADRC control method has been studied for the magnetorheological suspension system of automotive engines.The basic principles of self-anti-disturbance control strategy and whale optimization algorithm were demonstrated.Designed of a self-turbulence controller based on a two-degree-of-freedom magnetorheological suspension damping control system.The whale optimization algorithm was adopted to optimally tune the parameters.The damping effect of conventional PID control and passive control was compared and analyzed with the body vibration acceleration as the evaluation index.The results showed that the self-turbulence controller based on the whale optimization algorithm can give full utilization to the vibration isolation performance of the suspension system.5.Experiments were conducted on the dynamic characteristics of magnetorheological mounts.The dynamic characteristics have been experimentally studied using the MTS comprehensive test stand.The experimental results of dynamic characteristics were basically consistent with the simulation results.It showed that magnetorheological suspension has a good controllable range,which provided a theoretical basis for magnetorheological suspension control system. |
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