| Both the tire and suspension system are important parts of vehicle chassis system,and directly affect dynamic performances of vehicles.Traditional pneumatic tires have shortcomings such as easy puncture,easy burst,and easy abrasion,which is not in conformity with the development trend of"more comfortable,safer,and more energy-saving"vehicles in the future.The non-pneumatic tire,introduced into passenger-vehicles to replace the role of traditional pneumatic tires,can effectively overcome the drawback.Compared with traditional pneumatic tires,non-pneumatic tires have significantly increased radial stiffness and tire quality.As a result,it has a negative impact on the vehicle dynamics performances,which brings difficulties to its application in passenger-vehicles.In order to solve the above issues,supported by the National Natural Science Foundation of China（Project No.51975253）,the 1/4 suspension system was chosen as the research object in this paper.And the mathematical model of vertical mechanical characteristics has been established.Then,the linear motor electromagnetic active suspension was introduced to form a novel vibration reduction system with the non-pneumatic tire,and a PSO（Particle swarm optimization）-H∞/H2 robust control method built on gain switching was proposed to improve the vehicle dynamic performances.The main research contributions of this paper are as follows:Firstly,a novel vibration reduction system dynamic model of the non-pneumatic tire-electromagnetic active suspension was construed.Through the product test analysis method,the vertical mechanical characteristics of the non-pneumatic tire were obtained,and the mathematical model of its radial stiffness was constructed by the piecewise polynomial fitting method.Then,the novel vibration reduction system vertical dynamic model was constructed combined with the dynamic model of the 1/4 suspension system.Secondly,the vertical vibration negative effects of the non-pneumatic tire-electromagnetic active suspension and its formation mechanism were revealed.Through the study on the influence mechanism of tire stiffness and mass changes on the vibration response of the suspension system,the formation mechanism of negative effects of the non-pneumatic tire on the novel vibration reduction system was revealed;the system response difference between the traditional pneumatic tire-passive suspension system and the non-pneumatic tire-passive suspension system have been compared and analyzed in the time domain and frequency domain respectively to summarize the specific content of the negative effects.Then,the robust control of the novel vibration reduction system was conducted.Based on the system performance requirements and control requirements,a multi-objective robust control method was designed.On this basis,piecewise linearization was utilized to deal with the non-linear tire stiffness problem,and the improved particle swarm optimization algorithm was used to optimize the control parameter.The Kalman state observer was applied to estimate the unmeasurable state signals.And a PSO-H∞/H2 robust control method based on gain switching was proposed.Finally,the feasibility and effectiveness of the designed control method were verified.In the simulation analysis,the PSO-H∞/H2 robust control effects based on control gain switching under different classes of random roads were analyzed,and the performance of the designed state observer was also verified.At the same time,a hardware-in-the-loop test was designed,and the test result was consistent with the simulation result.Both the simulation and test showed that the designed control method can not only effectively suppress negative effects but also significantly improve the suspension system dynamic response. |
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