多支路油气悬架刚度阻尼耦合特性及控制方法研究

Interconnected hydro-pneumatic suspension is implemented at heavy multi-axle vehicles increasingly by its superior characteristics, such as damping, anti-roll, balancing axle load and so on. However, as for multi-branch hydro-pneumatic suspension, the stiffness and damping are coupled each other strongly, Which has become the key obstacle for developing suspension control technology and improving suspension performance. Aiming at the stiffness-damping coupling, this project will mainly focus on the research of stiffness-damping coupling mechanism and control algorithm in terms of multi-branch hydro-pneumatic suspension.The characteristics of hydro-pneumatic suspension not only related to magnitude of force, but also related to temperature variation and action time of force, which are accord with the characteristics of viscoelastic material. In view of that, the hydro-pneumatic suspension can be treated as viscoelastic system. Besides, fractional order has the advantages of describing the memory characteristics and evolution process of a physical change. The fractional order mathematical model of multi-branch interconnected hydro-pneumatic suspension is developed based on fractional order theory. Then, based on the model, the mechanism and factors of stiffness-damping coupling of multi-branch hydro-pneumatic suspension are deeply studied in the field of displacement, velocity and acceleration. And that will be tested and certified based on the hydro-pneumatic suspension test platform. In view of stiffness-damping coupling, based on theory of fractional order, the combination of local and overall control algorithm is proposed for multi-branch hydro-pneumatic suspension. This research work will provide the theoretic and technical foundation for the control algorithm research of multi-branch hydro-pneumatic suspension， moreover，it will be of great significance to development of suspension technology.

互连式油气悬架以优异的减振、抗侧倾、平衡轴荷等性能越来越多的在重型多轴车辆上应用，但是，其刚度阻尼耦合成为制约悬架控制技术发展与悬架性能提升的关键问题。针对刚度阻尼耦合的核心问题，项目将着重开展多支路油气悬架刚度阻尼耦合机理及控制算法研究。油气悬架特性不仅和外力大小有关，还和温度的改变、力的作用时间及加载历史都有关系，这些十分符合粘弹性物质的特点，而分数阶具有描述一个物理变化的记忆特性和衍变过程的优点，因此，将油气悬架系统整体等效为粘弹性系统，建立分数阶油气悬架模型。在位移、速度、加速度域内对刚度阻尼耦合机理及影响因素进行深入研究，并利用油气悬架测试平台进行试验验证，保证仿真分析的正确性。考虑到刚度阻尼耦合的特点，将输出力作为控制对象，基于分数阶理论，提出局部与整体相结合的分层控制算法，并进行仿真分析。本研究将为多支路油气悬架控制算法研究提供理论基础，对悬架技术的发展具有重要意义。

针对多支路油气悬架，基于分数阶理论，建立了非线性数学模型；基于模型，从活塞位移、速度域内对多支路油气悬架系统刚度阻尼耦合特性进行深入研究，并对各支路阀系参数、各蓄能器参数等相关影响因素进行分析，揭示了多支路油气悬架刚度阻尼是耦合的机理；通过多支路油气悬架台架试验，验证了刚度阻尼耦合特性理论分析的正确性；考虑到多支路油气悬架系统刚度阻尼耦合特性，采用局部PID与整体最优相结合的分层控制方法，并进行了平顺性仿真分析，验证了控制方法的有效性。