Parameter Design And Robustness Optimization Of A Nonlinear ISD Damping System For A Truck

The vehicle damping system is an important part of the car and has a great influence on the ride comfort and steering stability of the vehicle.The traditional"Spring-Damping"damping structure is difficult to adapt to complex road surfaces.And the appearance of the"Inerter-Spring-Damper"?ISD?damping structure breaks the shackles of the classical vibration isolation theory and has received extensive attention.At present,the deterministic model of the linear system is mostly used in the research of the ISD damping system.However,most of the research ignores the nonlinear characteristics of springs in actual engineering and the uncertainties in the process of machining and installation.Therefore,it is important to establish the mechanical model or physical model of the uncertain parameters,consider the hysteresis nonlinear characteristics of the spring in the automobile damping system and describe the working behavior of the damping system in a true and accurate way.In this paper,Dongfeng's damping system for a truck is the research object.Considering the nonlinearity of the suspension leaf spring and the uncertainty of the dynamic parameters,it is carried out that the parameter design and robustness optimization of the nonlinear ISD damping system.Firstly,the Bouc-Wen model is used to describe the hysteresis nonlinear characteristics of the suspension leaf spring.The static loading and unloading characteristics of the leaf spring and the dynamic loading and unloading characteristics of"equal frequency variation"and"equal amplitude conversion"are analyzed.A genetic algorithm based on the sum of the squares of the hysteresis displacements difference between the simulated data and the experimental data is constructed.And the key parameters of the Bouc-Wen model of the nonlinear leaf spring are identified.The results show that the error based on the energy dissipation ratio of the leaf spring simulation hysteresis loop and the experimental hysteresis loop under each working condition is less than 5%.Secondly,the dynamic model of the three-degree-of-freedom passive damping system model of 1/4 truck is established.The vibration analysis results show that the damping ratio of the passive damping system is too large.And parameter optimization is required to obtain the optimal damping ratio.Based on the nonlinear parameter identification results of leaf springs,four kinds of nonlinear ISD damping systems are established.Taking the vertical seat acceleration,seat working space,seat effective transmission rate,vertical body acceleration,suspension working space.Dunamic tyre load as the the objective functions,the parameters of the damping system are designed by an evolutionary many-objective optimization algorithm using reference-point-based nondominated sorting approach?NSGA-III?.The performance of the designed damping system is analyzed by combining the pseudo excitation method and the equivalent linearization method.And the structural parameters of the inerter were designed.The results show that the designed L₁ damping system can effectively reduce the system common amplitude value,and the vibration reduction effect in the 2-8Hz frequency band is significantly better than the traditional passive suspension.In addition,the vertical seat acceleration and the vertical body acceleration are increased by 20.17%and 16.28%respectively compared with the conventional passive suspension.And the seat working space and the seat effective transmission rate are increased by 4.55%and 8.80%respectively.It shows that the structure of L₁ damping system can effectively improve the ride comfort of the vehicle.Finally,a nonlinear ISD damping system model of parameter variation is established.The rapid perturbation method is used to analyze the influence of structural parameter variation of ISD damping system on vertical seat acceleration,seat working space,seat effective transmission rate,vertical bady acceleration,suspension working space and dynamic tyre load.Based on the improved e-indentation robust model,the robustness optimization design of the damping coefficient of the damper and the stiffness of the seat spring of the nonlinear ISD damping system is carried out.The results show that the quality parameters,stiffness parameters and damping parameters of the L₁ damping system have a great influence on the system response.And the inertance just has little impact on the system and can be ignored.The robustness optimization scheme of the L₁ damping system compensates for the shortcomings of the initial design.In the case where the mean value of each performance index is less than 4%,the vertical seat acceleration and the seat effective transmission rate robustness are increased by 13.74%and 13.58%.The work of this paper can not only be applied to the parameter design and robustness optimization of truck vibration damping system,but also provide reference for other similar system optimization design.At the same time,the improved e-indentation robust model proposed in this paper can also be applied to the optimization design of other systems.