Human Biodynamic Responses to Whole-Body Vehicular Vibration and Vibration Control

拟建的研究涉及与粘弹性座椅相结合的人体矢状面全身振动（WBV）反应的表征和建模，以及通过控制振动来预防潜在的振动损伤。在资源、建筑和工业领域使用的越野车表现出复杂的平顺振动和有限的方向稳定性。流行病学研究已经证实，除了降低工作效率外，许多工作车辆的振动幅度与驾驶员受伤报告之间存在很强的相关性。由于对更高负载能力和速度的需求不断增加，预计未来车辆将表现出更严格的WBV和不利的稳定性限制。考虑到人体对振动能量的吸收，生物动力学的表征对于振动控制系统（即二级和一级悬架）的设计至关重要，并有助于以人为本的未来工作车辆设计。因此，正在继续作出相当大的努力来确定生物动力学措施的特征，以便得出：(i)用于评估暴露风险的频率加权；（ii）应用于座椅设计和振动控制装置的生物动力学模型；（三）人体动力学模型，用于座椅的有效评估。然而，报告的响应总是在车身与刚性座椅和理想振动耦合的情况下获得的，这并不能代表车辆中普遍存在的条件。具有弹性阀座的本体联轴器实质上改变了其机械性能，从而影响了振动吸收。因此，迄今为止，报道的生物动力学反应和模型的应用取得了有限的成功。这主要是由于缺乏与弹性座椅和适当的测量系统的身体相互作用。此外，由于悬架对车辆稳定性的不利影响，通过悬架设计来控制平顺振动不能孤立地进行。因此，主要目标包括：(i)人体矢状面生物动力学响应的实验表征和建模与弹性座椅耦合，暴露于垂直和前后WBV；（ii）通过集成驾驶、操纵和稳定性的车辆模型设计创新的悬架。电阻式压力传感网格将用于测量身体-座位界面力和对WBV的生物动力学响应。在最近的一项研究中建立的测量系统的频率响应将用于补偿其有限的带宽。由于对身体质量、背部支撑和座椅弹性的依赖性较强，本研究将纳入三个范围内、座椅弹性性能不同的受试者。目标生物动力学反应将被定义为人体质量和座椅弹性的函数。从刚性座椅获得的响应将用于校准三种质量的多体生物动力学模型。校正后的模型将与座椅的有限元模型相结合，以表征机体与弹性座椅耦合时的生物动力学响应。通过悬架座椅的实验和仿真，验证了该模型在典型的垂直和前后车辆WBV下可靠地表示座员-乘员响应的可行性。该研究随后将集中在涉及轴间耦合液压-气动支柱的主悬架的创新设计上。结合转向杆的运动动力学、液压连接悬架的不同布局以及相关的轮胎-地形相互作用，将开发框架转向车辆的综合乘坐和操纵模型。

Proposed study concerns characterization and modeling of seated human responses to whole-body vibration (WBV) in the sagittal plane when coupled with visco-elastic seats and prevention of potential vibration injuries through control of vibration. Off-road vehicles employed in the resource, construction and industrial sectors exhibit complex ride vibration and limited directional stability. Epidemiological studies have established strong correlations between magnitudes of vibration of many work vehicles and reported injuries among drivers, in addition to reduced work efficiency. Owing to increasing demand for higher load capacity and speeds, future vehicles are expected to exhibit more severe WBV and adverse stability limits. Considering the absorption of vibration energy by the body, characterization of biodynamics is vital for design of vibration control systems, namely secondary and primary suspensions, and to contribute to human-centered future work vehicles designs. Considerable efforts are thus continuing to characterize biodynamic measures for deriving: (i) frequency-weighting for assessing exposure risks; (ii) biodynamic models for applications in seating design and vibration control devices; and (iii) anthropodynamic manikins for efficient assessments of seats. The reported responses, however, have been invariably obtained with body coupled with rigid seats and idealized vibration, which are not representative of conditions that prevail in vehicles. The body coupling with an elastic seat substantially alters its mechanical properties and thereby affects the vibration absorption. Consequently, applications of reported biodynamic responses and models have met limited success thus far. This is mostly attributed to lack of body interactions with elastic seats and adequate measurement systems. Furthermore, the control of ride vibration through suspension designs cannot be conducted in an isolated manner due to adverse effects of suspension on vehicle stability. The primary objectives thus include: (i) experimental characterization and modeling of sagittal plane biodynamic responses of human body coupled with elastic seats and exposed to vertical and fore-aftl WBV; and (ii) designs of innovative suspensions through integrated ride, handling and stability vehicle models. The resistive pressure sensing grids will be used to measure body-seat interface forces and biodynamic responses to WBV. The frequency response of the measurement system, established in a recent study, will be applied to compensate for its limited bandwidth. Owing to strong dependence on body mass, back support and seat elasticity, the study will include subjects with body mass within three ranges and varying seat elastic property. The target biodynamic responses will be defined as functions of body mass and seat elasticity. The responses, obtained for a rigid seat, will be used to calibrate multi-body biodynamic models of the body of three masses. The calibrated models will be integrated with a finite element model of the seat so as to characterize the biodynamic responses of the body coupled with elastic seat. The feasibility of the models to reliably represent the seat-occupant response under typical vertical and fore-aft vehicle WBV will be established through experiments and simulations with suspension seats. The study will subsequently focus on innovative designs in primary suspensions involving inter-axle coupled hydro-pneumatic struts. An integrated ride and handling model of a frame-steer vehicle will be developed incorporating kineto-dynamics of the steering struts, different layouts of hydra-connected suspension and correlated tire-terrain interactions.