汽车悬架振动系统的多目标优化设计

本文首先分析了多目标优化方法,接下来对悬架模型建立及仿真进行分析,最后对遗传算法的多目标优化作具体阐述,同时介绍了多目标优化方案,希望给行业内人士以借鉴和启发。

汽车悬架振动系统的若干控制技术和方法

汽车悬架振动系统在汽车制造装配中的应用对于保障汽车行驶过程中的平顺性与各项操作实施的稳定性具有非常积极的作用,同时其对于汽车行驶过程中的行驶速度亦有非常密切的影响作用。加强对汽车悬架振动系统的有效研究,同时加强对诸多新技术、新材料的研发和应用,使得汽车悬架振动系统在汽车的装配制造过程中其振动控制水平能够越来越低,对于促进汽车各项性能的进步具有非常积极的作用。基于此,本文将针对当前汽车悬架振动系统的主要类型进行总结阐述,同时以此为基础针对汽车悬架振动系统的控制技术与控制方法进行探讨总结。

Semi-active control for vibration attenuation of vehicle suspension with symmetric MR damper

A semi-active force tracking PI controller is formulated and analyzed for a magnetorheological (MR) fluid-based damper in conjunction with a quarter-vehicle model. Two different models of the MR-damper are integrated into the closed-loop system model, which includes: a model based upon the mean force-velocity (f-v) behaviour; and a model synthesis comprising inherent nonsmooth hysteretic force and the force limiting properties of the MR damper. The vehicle models are analyzed to study the vibration attenuation performance of the MR-damper using the semi-active force tracking PI control algorithm. The simulation results are also presented to demonstrate the influence of the damper nonlinearity, specifically the hysteresis, on the suspension performance. The results show that the proposed control strategy can yield superior vibration attenuation performance of the vehicle suspension actuated by the controllable MR-damper not only in the sprung mass resonance and the ride zones, but also in the vicinity of the wheel-hop. The results further show that the presence of damper hystersis deteriorates the suspension performance.

Reliability-based robust multi-obj ective optimization of a 5-DOF vehicle vibration model subjected to random road profiles

Ride and handling are two paramount factors in design and development of vehicle suspension systems. Conflicting trends in ride and handling characteristics propel engineers toward employing multi-objective optimization methods capable of providing the best trade-off designs compromising both criteria simultaneously. Although many studies have been performed on multi-objective optimization of vehicle suspension system, only a few of them have used probabilistic approaches considering effects of uncertainties in the design. However, it has been proved that optimum point obtained from deterministic optimization without taking into account the effects of uncertainties may lead to high-risk points instead of optimum ones. In this work, reliability-based robust multi-objective optimization of a 5 degree of freedom （5-DOF） vehicle suspension system is performed using method of non-dominated sorting genetic algorithm-II （NSGA-II） in conjunction with Monte Carlo simulation （MCS） to obtain best designs considering both comfort and handling. Road profile is modeled as a random function using power spectral density （PSD） which is in better accordance with reality. To accommodate the robust approach, the variance of all objective functions is also considered to be minimized. Also, to take into account the reliability criterion, a reliability-based constraint is considered in the optimization. A deterministic optimization has also been performed to compare the results with probabilistic study and some other deterministic studies in the literature. In addition, sensitivity analysis has been performed to reveal the effects of different design variables on objective functions. To introduce the best trade-off points from the obtained Pareto fronts, TOPSIS method has been employed. Results show that optimum design point obtained from probabilistic optimization in this work provides better performance while demonstrating very good reliability and robustness. However, other optimum points from deterministic optimizations violate the regarded constraints in the presence of uncertainties.

Semi-active control of a vehicle suspension using magneto-rheological damper

A semi-active magneto-rheological （MR） damper was experimentally investigated and compared to an original equipment manufacturer （OEM） damper for a passenger vehicle, by using a quarter car models. A full-scale two-degree-of-freedom quarter car experimental set-up was constructed to study the vehicle suspension. On-off skyhook controller and Fuzzy-Lyapunov skyhook controller （FLSC） were employed to control the input current for MR damper so as to achieve the desired damping force. Tests were done to evaluate the ability of MR damper for controlling vehicle vibration. Test results show that the semi-active MR vehicle suspension vibration control system is feasible. In comparison with OEM damper, on-off and FLSC controlled MR dampers can effectively reduce the acceleration of vehicle sprtmg mass by about 15% and 24%, respectively.