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

拟议的研究涉及表征和建模的人坐在全身振动（WBV）在矢状面时，再加上粘弹性座椅和预防潜在的振动损伤，通过控制振动。在资源、建筑和工业部门使用的越野车辆表现出复杂的行驶振动和有限的方向稳定性。 流行病学研究已经确定了许多工作车辆的振动幅度与驾驶员中报告的伤害之间的强相关性，以及降低的工作效率。由于对更高负载能力和速度的需求不断增加，预计未来的车辆将表现出更严重的WBV和不利的稳定性极限。考虑到人体对振动能量的吸收，生物动力学特性对于振动控制系统（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，以确定生物动力学措施的特点，以便：（一）评估接触风险的频率加权;（二）应用于座椅设计和振动控制装置的生物动力学模型;（三）有效评估座椅的生物动力学人体模型。然而，所报告的响应总是在车身与刚性座椅和理想化振动耦合的情况下获得的，这并不代表车辆中普遍存在的条件。本体与弹性座的联接显著地改变了其机械特性，从而影响振动吸收。因此，迄今为止，所报道的生物动力学响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，不能以孤立的方式通过悬架设计来控制行驶振动。因此，主要目标包括：（i）与弹性座椅耦合并暴露于垂直和前后WBV的人体矢状面生物动力学响应的实验表征和建模;以及（ii）通过集成的行驶、操纵和稳定性车辆模型设计创新悬架。电阻压力传感网格将用于测量身体-座椅界面力和对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强烈依赖性，研究将包括身体质量在三个范围内且座椅弹性性质不同的受试者。目标生物动力学响应将被定义为身体质量和座椅弹性的函数。刚性座椅获得的响应将用于校准三个质量的身体的多体生物动力学模型。将校准后的模型与座椅的有限元模型集成，以表征与弹性座椅耦合的身体的生物动力学响应。将通过悬挂座椅的实验和模拟来建立模型的可行性，以可靠地代表在典型的垂直和前后车辆WBV下的座椅-乘员响应。随后，该研究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。将开发车架转向车辆的综合行驶和操纵模型，其中包括转向支柱的运动动力学、液压连接悬架的不同布局以及相关的轮胎-地形相互作用。

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.