Performance Analysis Of MISD Suspension With Displacement-dependent Mem-inerter

Memory elements are capable of remembering the entire motion history of the input variables and have the ability to automatically adjust their own parameters to changes in external operating conditions.While the application of non-linear spring and damper elements in suspension systems has been widely studied,the physical device of a non-linear mem-inerter and its application in suspensions has rarely been reported.In this paper,a new mechanical mem-inerter device is designed,a non-linear MISD(Mem-inerter-SpringDamper)suspension system with inertial coefficients that can adapt to vehicle load changes is constructed,the equivalent inertia theorem of the mem-inerter and the semi-active inerter is proved based on energy calculation methods,an equivalent semi-active model of the meminerter is established and the equivalence of the MISD suspension and the semi-active ISD suspension is confirmed.Simulations and experiments show that the introduction of the mem-inerter element can bring load adaptability to the suspension and improve the ride smoothness of the vehicle.Firstly,the general intrinsic relationship model of memory elements is derived from the three-dimensional triangular periodic table of mechanical memory elements,and the energy calculation method applicable to memory elements is proposed and the integral Lagrangian method applicable to non-self-conjugating systems containing memory elements is developed,laying the theoretical foundation for proving the equivalence between meminerter and semi-active inerter and testing the performance of MISD suspensions.Secondly,two mechanical displacement-dependent mem-inerter models with positive and negative correlation between the inertial coefficients and the relative displacement of the two ends are modelled,and the memory characteristics of the two devices are verified by simulation.The equivalence between the displacement-dependent mem-inerter and the semiactive inerter is demonstrated according to the energy calculation method,and the equivalent semi-active model of the mem-inerter is established.Again,the integral Lagrangian method is applied to establish the dynamics equations of the MISD suspension system,a multi-objective function is established based on the suspension performance evaluation index,and a genetic algorithm is used to optimize the key suspension parameters.The simulation verifies the equivalence of MISD suspensions with the semi-active ISD suspensions.The performance of the MISD suspension with positive displacement correlation and negative displacement correlation is compared.The positive correlation MISD suspension with better overall performance is compared with the conventional passive suspension and ISD suspension to study the response characteristics of the three suspensions under impulsive and random inputs.The results show that the introduction of mem-inerter component can improve the smoothness of the suspension and improve the handling stability of the vehicle.Finally,hardware-in-the-loop test platform for the semi-active ISD suspension was established based on NI Veri Stand simulation test software,and the equivalence of the two suspensions is further verified through tests,which show that the performance of the MISD suspension with mem-inerter is basically the same as that of the semi-active suspension with initial displacement control strategy.Based on the equivalence results,the performance of the semi-active ISD suspension is compared with that of the passive suspension and the ISD suspension to verify the effectiveness and feasibility of the MISD suspension.