基于多端口机械网络理论的ISD悬架匹配机理与控制

Inerter-spring-damper suspension based on inertance and damping control has a distinguishing feature of constant stiffness, variable inertance and damping characteristics. Control and match between the ISD suspension and vehicle is a new topic of vehicle system dynamics. According to the similarity principle of electrical and mechanical analogy, in this project, dynamic matching problem of ISD suspension and vehicle was equated to the impedance matching problem in mechanical network. By using multi-port mechanical network theory, optimum match between ISD suspension and vehicle impedances was summarized as a class of multi-port network maximum power transmission problem of constant stiffness, variable inertance and damping. After the mathematical model of this problem was solved by using network transformation and Lagrange multiplier method, the match mechanism between ISD suspension impedance and the inner impedance of vehicle was revealed. In order to establish the mapping relationships between the inertance characteristics, damping characteristics, the suspension impedance and pipe diameter, MR excitation current respectively, work characteristics of magnetorheological inerter was researched. On this basis, dynamic tracking control strategy of the maximum power point of ISD suspension based on impedance match was proposed, and closed-loop PID control method based on impedance modification was presented, to achieve optimum match between suspension and vehicle impedances, to ensure that the suspension always absorb vibration energy at maximum power, and to improve ride comfort with taking account of handling stability. Finally, the bench test and road test were carried on. The project is to provide theory and method support for applications of ISD suspension.

惯容和阻尼联合控制的“惯容－弹簧－阻尼”（ISD）悬架具有定刚度、变惯容、变阻尼特性的特点，与整车的匹配和控制是车辆系统动力学面临的一个新课题。项目根据机电相似原理，将ISD悬架与整车匹配的动力学问题等效为机械网络中的阻抗匹配问题，运用多端口机械网络理论将阻抗最佳匹配归结为一类刚度不变、惯容和阻尼可变的多端口网络最大功率传输问题，利用网络变换及Lagrange乘数法求解其数学模型，分析悬架阻抗与整车内阻抗的匹配规律；研究磁流变惯容器工作特性，建立惯容调节管直径和MR励磁电流分别与惯容和阻尼特性、悬架阻抗之间的映射关系；在此基础上，提出基于阻抗匹配的最大功率点动态跟踪控制策略及阻抗修正的闭环PID控制方法，实现ISD悬架和整车阻抗的最佳匹配，确保悬架始终以最大功率吸收振动能量，进一步提高行驶平顺性并兼顾操纵稳定性。最后进行台架和道路试验验证。项目旨在为ISD悬架的应用提供新的理论和方法支持。

半主动控制的“惯容-弹簧-阻尼”(ISD)悬架具有定刚度、变惯容、变阻尼特性的特点,与整车的匹配和控制是车辆系统动力学面临的一个新课题。本项目在国家自然科学基金委的资助下,开展了半主动ISD悬架与整车的匹配机理及控制研究，主要研究内容包括：① 设计研制了一种惯容系数可调的新型流体惯容器装置，并进行了工作特性试验，采用系统识别的方法得到了惯容器的频域响应特性，分析惯容器的幅频和相频特性，研究伴随惯容的寄生阻尼产生机制，建立了流体惯容器非线性模型。② 针对传统悬架与车辆阻抗失配的问题，在传统悬架的结构基础上引入惯容器，提出“惯容－弹簧－阻尼”三元件并联的ISD悬架结构。基于该结构模型，根据机械网络理论，把悬架与车辆的阻抗匹配问题归结为机械网络最大功率传输问题。运用最大功率传输理论，研究阐明了悬架与整车的匹配机理，并建立传统动力学模型验证了匹配机理的正确性。③ 基于“惯容－弹簧－阻尼”悬架系统惯容与阻尼的耦合机制，提出最优控制协调控制方法；在此基础上，综合悬架各性能指标设计了最优控制器，对比分析了半主动ISD悬架的时域响应以及频域响应。随机路面激励下，在车速为20m/s时，车身加速度均方根值降幅9.49%，悬架动行程均方根值降幅35.04%，轮胎动载荷均方根值降幅0.38%，从仿真角度验证了半主动ISD悬架的性能优越性。④ 搭建基于Matlab/dSPACE 的半实物实验平台，验证了控制方法的有效性，进一步明确了ISD悬架与整车的匹配机理及其对整车动力学性能的影响规律。在随机输入激励试验中，相较于传统被动悬架，半主动ISD悬架在车速为30km/h、40km/h、50km/h时车身加速度均方根值分别减小了4.61%，3.78%，3.76%；悬架动行程均方根值分别减小了7.63%，3.89%，5.01%。试验结果与理论研究相吻合，进一步验证了半主动ISD悬架能有效改善车辆行驶的综合性能，兼顾行驶平顺性和操纵稳定性的要求。研究成果可为半主动ISD悬架的应用提供新的理论和方法支持。