主动汽车悬架的非线性控制

本文采用１／４车模型对天棚阻尼器和主动悬架的动力学性能进行分析，针对执行器的非线性特性，探讨了微分几何法和反馈法线必互法在主动悬架控制中的应用，在系统控制设计中采用了离散滑模法，仿真结果显示非线性控制律能有效地改善主动悬架的隔振特性。     

汽车主动悬架的自校正控制

主动悬系统能使车辆的乘坐舒适性和操纵稳定性同时得到改善，其中执行机构和控制算法的优劣决定了该系统的性能。     

Active Control of Non-stationary Response of Vehicles with Nonlinear Suspensions

Active control of non-stationary response of a single degree of freedom vehicle model with nonlinear passive suspension elements is considered in this paper. The method of equivalent linearization is used to derive the equivalent linear model and the optimal control laws are obtained by using stochastic optimal control theory based on full state information. Velocity squared quadratic damping and hysteresis type of stiffness nonlinearities are considered. The effect of the nonlinearities on the active system performance is studied. The performance of active suspensions with nonlinear passive elements is found to be superior to the corresponding passive suspension systems.     

Active Control of Non-stationary Response of Vehicles with Nonlinear Suspensions

SUMMARY

Active control of non-stationary response of a single degree of freedom vehicle model with nonlinear passive suspension elements is considered in this paper. The method of equivalent linearization is used to derive the equivalent linear model and the optimal control laws are obtained by using stochastic optimal control theory based on full state information. Velocity squared quadratic damping and hysteresis type of stiffness nonlinearities are considered. The effect of the nonlinearities on the active system performance is studied. The performance of active suspensions with nonlinear passive elements is found to be superior to the corresponding passive suspension systems.     

The Application of Linear Optimal Control Theory to the Design of Active Automotive Suspensions

SUMMARY

Some linear stochastic control theory relevant to the design of active suspension systems subject to integrated or filtered white noise excitation is reviewed, and application of the theory to a particular problem is considered. The problem considered is the well known quarter car problem in which a control law which minimises a performance function representing passenger discomfort, suspension working space, and tyre load fluctuations is required. With full state feedback, the requirement for a formulation of the problem which leads to the system under consideration being observable and controllable is referred to, and it is shown how a well known coordinate transformation enables this requirement to be satisfied. With limited state (or output) feedback, problem formulations which will avoid potential numerical problems in deriving the optimal control are described. Example solutions are included in order to illustrate the methods.     

The Response of Active and Semi-active Suspensions to Realistic Feedback Signals

A simple vehicle model is presented incorporating passive, active, and semi-active suspensions. When the desired feedback variables are ideally available, the system response is well understood and excellent sprung mass isolation results. More often than not, the measured variables must be signal processed in some manner prior to their use in some control algorithm. This paper presents the expected response of a simple vehicle with an active and/or semi-active suspension, subject to non-ideal feedback information.     

The Response of Active and Semi-active Suspensions to Realistic Feedback Signals

SUMMARY

A simple vehicle model is presented incorporating passive, active, and semi-active suspensions. When the desired feedback variables are ideally available, the system response is well understood and excellent sprung mass isolation results. More often than not, the measured variables must be signal processed in some manner prior to their use in some control algorithm. This paper presents the expected response of a simple vehicle with an active and/or semi-active suspension, subject to non-ideal feedback information.     

A Low-Cost Transfer Function Identification Technique for Automotive Suspensions

An alternative technique for identifying the transfer function of automotive suspension systems is presented in this paper. The method establishes a frequency response from which the transfer function can be determined by using a low cost test rig developed for the purpose. This results in a transfer function matrix which can include asymmetry in the suspension, tyre stiffness and damping. The technique is validated by comparing results for a two-wheeled trailer with those obtained on a conventional hydraulic test rig. Results from this procedure may be used to evaluate passive or active suspension systems or to feed into a suspension modelling process for such purposes as active suspension control strategy development.     

Railway Vehicle Active Suspensions

This paper reviews the state-of-the-art of active suspensions for use on railway vehicles. The primary focus of the paper is on ride quality control, both vertical and lateral, and on lateral stability control.

The section on theoretical considerations summarizes the results of a one-degree of freedom optimization and then investigates analytically the use of active suspensions for lateral ride and stability augmentation. It is shown that separate control structures using different measurements and actuator actions are very effective in controlling both ride quality and stability.

A section on a survey ofcurrent activities reviews published research on active railway suspension work around the world.

Finally a concluding section indicates future trends in active suspension applications.     

Anti-Roll and Active Roll Suspensions

Full car roll model is used to show an anti-roll control like that in Citroen's Xantia Activa and the proposed active roll with an in-series active suspension. Computed responses to pulse-shaped anti-phase road unevenness as well as to lateral acceleration in comparison with passive suspension are given in the paper. Also stability values for all parameters can be found.     

Anti-Roll and Active Roll Suspensions

Full car roll model is used to show an anti-roll control like that in Citroen's Xantia Activa and the proposed active roll with an in-series active suspension. Computed responses to pulse-shaped anti-phase road unevenness as well as to lateral acceleration in comparison with passive suspension are given in the paper. Also stability values for all parameters can be found.     

采用电流变阻尼器汽车悬架的半主动控制研究

采用电流变阻尼器作为汽车悬架系统的减振器,应用最优控制策略,设计了汽车悬架的半主动控制系统。大量仿真实验表明,采用电流变阻尼器的半主动控制悬架系统有效地改善了汽车驾驶平顺性和乘坐舒适性。     

Optimal Adaptive Active Suspensions for a Full Car Model

In order to present a useful method for designing active suspension of a vehicle, a linear full-car model is used in this investigation. In this model, the dampers of passive system are totally replaced by actuators. The actuators are controlled with optimal full state vector feedback. After determining feedback coefficients, the responses of active and passive systems were compared and it was found that performance of active system is much superior. It is desired that, changes in vehicle parameters would not affect the system's performance and hence should not violate its optimality. In other words, the system should behave adaptively using Model Reference Adaptive Control. The optimally controlled active suspension was used as a model for the active suspension of vehicle. In this way, the suspension of vehicle is controlled in such a way that its output approaches to that of the optimal active model. Thus the suspension should behave just like the optimal one.     

Theoretical Limitations in Active Vehicle Suspensions

Vehicle suspensions in which forces are generated in response to feedback signals by active elements obviously offer increased design flexibility compared to conventional suspensions using passive elements such as springs and dampers. It is often assumed that if practical difficulties are neglected, active systems could in principle produce arbitrary ideal, behavior. It is shown, using a simple linear two degree-of-freedom suspension system, model that even using complete state feed back and in the case of in which the system is controllable in the control theory sense, there still are limitations to suspension performance in the fully active case. If the ideal suspension performance is defined based on low-pass filtering of roadway unevenness inputs, an active suspension may not offer much better performance than a partially active or adaptive passive suspension depending upon the values of certain vehicle parameters.     

橡胶元件在汽车悬架中的应用分析

介绍了橡胶元件在汽车悬架中的应用现状,分析了橡胶衬套力学特性的理论研究方法和试验技术,并对某汽车悬架橡胶衬套进行了有限元分析和试验验证。阐述了橡胶衬套对汽车平顺性、操纵稳定性及高频NVH特性的影响,并通过实例讨论了橡胶衬套对悬架运动学性能的作用和衬套刚度优化方法。指出,需进一步研究橡胶元件对汽车高频动态性能的影响。     

道路激励作用下的汽车后桥动力响应分析

结合某微型汽车后桥动力响应分析,对道路激励作用下的动力响应问题进行了深入的研究,并用大质量／大刚度法和拉格朗日乘子法计算了该汽车后桥的动力响应。     

Preview Estimation and Control for (Semi-) Active Suspensions

SUMMARY

An active suspension with preview is tested for rounded pulses and a stochastic road surface, and is compared to a passive suspension. The spectacular performance improvement obtained for a step function as road surface is not achieved but the improvement is still significant. The frequency response of the active suspension is determined for comparison with some suspension systems found in literature

An observer to reconstruct the preview information is presented. No model of the road surface is needed. From simulations, it appears that the observer reconstructs both deterministic and stochastic road surfaces satisfactory. However, the influence of measurement noise is not reduced sufficiently.     

Active Suspensions Based on Fast Load Levelers

SUMMARY

A class of active suspensions is presented which provides near optimum isolation of base motion as well as zero static deflection for force disturbances using a simple type of feedback. The load leveling effect is rapid with the system stabilized using isolated mass velocity feedback both for a semi-active damper and for the load leveler. The system can be made energy conservative and fail safe since the system reverts to a reasonable passive isolator if the load leveling effect and even if the active damping effect is switched off. The system could be incorporated in automotive vehicles with some extension of the feedback control to account for several aspects of body motion.     

Optimal Linear Active Suspensions with Integral Constraint

This paper considers the application of linear optimal control to the design of an active automobile suspension system. By inclusion of an integral constraint in the performance index it is possible to achieve zero steady state axle to body response to both static body forces and ramp road inputs. Full state feedback is achieved by reconstructing the state variables from easily measured quantities.     

Active Suspensions Based on Fast Load Levelers

A class of active suspensions is presented which provides near optimum isolation of base motion as well as zero static deflection for force disturbances using a simple type of feedback. The load leveling effect is rapid with the system stabilized using isolated mass velocity feedback both for a semi-active damper and for the load leveler. The system can be made energy conservative and fail safe since the system reverts to a reasonable passive isolator if the load leveling effect and even if the active damping effect is switched off. The system could be incorporated in automotive vehicles with some extension of the feedback control to account for several aspects of body motion.