基于靶能量传递的多维耦合汽车摆振非线性能量转迁减振策略研究

Multi-dimensional dynamic coupling can be found between steering system, suspension, tire, and et al., which can make considerable influence on the dynamic behavior of vehicle shimmy system. As a result, vehicle shimmy system with consideration of vertical and lateral dynamic coupling is employed as research object, and in-depth analysis of its multi-dimensional coupled nonlinear dynamic behavior and energy transfer mechanism is carried out. Based on these efforts, the strategy of nonlinear energy transfer and vibration attenuation of vehicle shimmy based on targeted energy transfer(TET) is discussed. It is helpful to attenuate the vehicle shimmy, and also provide a potential method for energy harvesting of vehicle, especially for new energy vehicles. The multi-dimensional dynamic coupling mechanism between sprung weight displacement, deformation of suspension and dynamic load, lateral force of tire will be analyzed, and the nonlinear dynamic model of vehicle shimmy system with consideration of vertical and lateral dynamic coupling will be established. Based on the model mentioned above, increment harmonic balance method(IHB) will be applied to investigate the dynamic stability and bifurcation characters of the system. Dynamic response of vehicle shimmy system will be analyzed based on numerical analysis, and evolution law of its dynamic behavior exposed to various disturb excitations will be investigated. Initial value characters and global dynamic behavior of vehicle shimmy system will be analyzed based on cell mapping method. Nonlinear normal modes of the system will be analyzed. The feasibility and technological approaches for nonlinear energy transfer and vibration attenuation of vehicle shimmy system will be discussed with frequency-energy relation diagram and nonlinear modal trace. Based on the efforts mentioned above, nonlinear vibration absorber based on TET will be designed for nonlinear energy transfer and vibration attenuation of vehicle shimmy, and experimental evaluation of the proposed method will be carried out with retrofitted model car.

汽车转向系与行驶系之间存在多维动力学耦合，对其摆振系统动力学行为产生重要影响。为此，以考虑垂向/侧向动力学耦合的汽车摆振系统为研究对象，深入分析其耦合非线性动力学行为及系统的能量传递转换机理，并探讨基于靶能量传递（TET）的汽车摆振非线性能量转迁减振策略，减小摆振的同时可为振动能量高效收集利用提供新的思路。重点分析簧载质量、悬架与轮胎等之间的多维动力学耦合机制，构建垂向/侧向动力学耦合的汽车摆振系统非线性动力学模型。应用增量谐波平衡法（IHB）等考察系统的动力学稳定性及分岔特性，基于数值分析考察摆振系统的动力学响应，明确系统动力学行为的演变规律，并应用胞映射法分析系统的初值特性和全局动力学行为。计算分析系统的非线性模态，利用频能关系图和非线性模态迹线分析非线性模态能量交换需满足的条件，探讨基于TET的非线性吸振器设计方案，尝试对汽车摆振进行非线性能量转迁减振，并通过样车试验验证其有效性。

车辆转向系与轮胎和悬架系统之间存在多维运动学和动力学耦合，由此会对车辆摆振系统的动力学行为产生重要影响。本项目以考虑垂向/侧向动力学耦合的车辆摆振系统为研究对象，面向多维耦合动力学建模分析需要，对轮胎动力学特性及其参数辨识等进行了探讨，分析了簧载质量、悬架与轮胎等之间的多维运动学和动力学耦合机制，构建了垂向/侧向动力学耦合的汽车摆振系统非线性动力学模型。对车辆摆振系统的耦合非线性动力学行为进行了深入探讨，分析了摆振系统在不同工况干扰激励下的动力学行为及其演变规律。对车辆摆振系统的能量传递转换规律进行了分析，提出了采用靶向能量传递对车辆摆振进行非线性能量转迁减振策略，通过仿真算例验证了采用NES抑制车辆摆振的可行性，并通过实车道路试验对相关结论进行了验证。项目重要研究结论如下：.1）垂/侧向耦合对摆振系统动态响应的影响不容忽视，增加转向系阻尼和悬架阻尼、减小悬架刚度和主销后倾角、减小整车质量和簧载质量质心到其侧倾轴的距离均是抑制车辆摆振的有效措施。.2）共振车速工况下，转向系和悬架系统之间几乎不进行能量传递转换；在自激摆振发生车速区间内，能量在各子系统之间进行着传递转换，增大转向系和悬架阻尼均可达到抑制汽车摆振的目的。.3）车辆摆振系统的两个平衡点在整个车速区间均是不稳定的，而另一个零平衡点存在一个失稳的车速区间。.4）轮胎非线性约束通常不会改变摆振系统失稳车速区间及运动形态，但会对摆振幅值产生影响。考虑路面激励影响时，轮胎动载荷对松弛长度和接地印迹长度的影响需要引起关注，轮胎非线性约束对汽车摆振的影响更加明显。.5）揭示了车辆多自由度耦合摆振系统的能量传递转移机制，提出了能量迁移调控的抑振策略，通过数值算例验证了NES抑制车辆摆振的可行性。.项目研究成果进一步丰富和完善了车辆摆振系统动力学理论体系，并对底盘系统的匹配设计优化和进一步改善整车操纵性能提供了理论依据。