【作者】 汪洪波；

【导师】 方敏；

【作者基本信息】 合肥工业大学 ， 控制理论与控制工程， 2006， 硕士

【摘要】 随着汽车主动悬架系统控制研究的不断深入,采用最优控制、鲁棒控制等现代控制理论方法,能获得较好控制性能的主动悬架系统。但是由于汽车本身的复杂性,所设计出的控制器的阶数往往较高,这将影响系统的可靠性、实时性,给控制器的工程实现带来困难。 汽车主动悬架和电动助力转向系统是汽车的两个重要的子系统。对两者分别进行控制后,简单组成的系统的性能往往不令人满意。通过集成控制综合提高系统性能是重要的研究方向。 针对以上两个问题,本文做了以下工作: 1.在建立七自由度主动悬架系统的14阶状态空间模型的基础上,设计了H_∞控制器,应用Hankel范数最优降阶方法研究了主动悬架高阶H_∞控制器的降阶问题。采用Hankel范数最优降阶方法,能够较大程度地降低控制器的阶数且闭环控制性能损失较小。通过与模态截取法、均衡截取法相比较,Hankel范数最优降阶法具有更好的降阶效果。 2.本文分别采用基于模型误差最小和基于闭环性能指标最优的频率加权方法,研究了降阶控制器的设计问题。通过选取适当的加权传递函数,可保证降阶闭环系统的稳定性。采用频率加权互质分解的控制器降阶方法,不仅很大程度地降低了主动悬架高阶控制器的阶数,而且降阶控制器能获得与全阶控制器十分相近的闭环控制性能。 3.研究了主动悬架和电动助力转向的集成控制问题。设计了主动悬架和转向集成系统的鲁棒控制器,将降阶主动悬架H_∞控制系统与电动助力转向PID控制系统构成的集成控制系统与全阶集成控制系统的性能进行了比较。降阶集成控制系统能取得与全阶集成控制系统十分相近的控制性能。 4.对主动悬架和电动助力转向集成控制系统进行了实车道路试验,使用汇编语言和C51语言编写P87C591单片机程序实现集成控制算法。主动悬架和电动助力转向集成控制系统能有效地提高车辆操纵轻便性、行驶平顺性。更多还原

【Abstract】 In order to improve the performance of active suspension system, control of active suspension has attracted researchers’ interest. The performance of the active suspension system can be significantly improved, but the designed controller is often of high-order derived by the modern control theory, such as optimal control and robust control. The high-order controller will bring bad influences in the control system, for example its reliability will be worse and engineering implementation will be harder.The active suspension system and the electric power steering system are two important subsystems of the vehicle. After applying control to the two systems, the performances of the integrated system by simply combination of them are often unsatisfactory. The integrated control is an important direction.This thesis has carried out the following work for the above two problems.1. The model of a 7 degree-of-freedom active suspension system is firstly built, which has a minimal state-space realization with 14-order. Then an H_∞ controller is designed based on the model. The order-reduction problem of the high-order controller is studied by utilizing optimal Hankel-norm reduction method(OHNR). The controller-order can be largely reduced, and the closed-loop control performances are not degraded much. By compared with the modal truncation method and balanced truncation method, OHNR can obtain the best reduction effect.2. By utilizing model approximation minimization based and closed-loop performance optimum based methods respectively, the lower-order controller design problem is studied. By choosing appropriate weighted transfer functions, the stability of reduced-order closed-loop system could be maintained. By utilizing frequency-weighted coprime factorization based controller method, the order of active suspension controller can not only be considerably reduced, but also the lower-order controller could obtain the very similar closed-loop control performance with the full-order one.3. The integrated control of the active suspension system and electric power steering system is studied. Robust controller of active suspension and steeringintegrated system is designed. The performances are compared between the lower-order integrated control system consisting of the lower-order active suspension Hx control system and electric power steering PID control system and full-order one. The lower-order integrated control system could obtain the very similar control performances with the full one.4. The active suspension and electric power steering integrated control system for road test is designed. The assembly language and C51 language is utilized to compile P87C591 single-chip computer programme to realize the integrated control algorithm. The active suspension and electric power steering integrated control system indeed improves the vehicle handling and ride comfort.更多还原