表面质地在触觉传感中的编码模式

To bridge the surface quality of fabric and the evoked neural responses of tactile mechanoreceptors, this project develops a hybrid method of mathematical modelling, simulation and experimental validation. Firstly, a fraction frictional contact model between fabric and fingertip skin is built on the basis of contact mechanic theory for rough surfaces, and both geometrical and materials properties of fabrics as well as human fingertip are considered. In terms of surface quality of different fabrics, the friction-induced skin mechanical responses are explored by the built frictional contact model. And then, the tactile friction experiments between fabric samples and the artificial tactile skin as well as human skin are performed, the bio-tribology phenomenon, the stimulus-response relationship and the psychophysical relationship are analyzed. Meanwhile, the electeromechanical transduction relationships of tactile mechanoreceptors are inferred from the known neurophysiological properites. Finally, the obtained results are applied to built a coupling fabric-skin-mechanoreceptor neuromechanical model, which simulates the responses of cutaneous mechanoreceptors embedding in human fingertip to the friction-induced mechancial stimulus from different fabrics. By modelling and simulation, it is investigated for the mapping relationship between fabric surface qualities, skin mechanical responses and evoked neural responses. From these studies, the the coding schemes of surface qualities during tactile sensing are established. The obtained conclusion will provid a significant theory support and technical guide for tactile interface deveolopment, brand prorection and tactile dysfunction rehabilitation.

为了构建物体的表面质地和皮肤触觉感受体的诱发神经信号之间的桥梁，本项目以理论建模、数值仿真和试验探索相结合展开研究。首先，根据织物和指尖皮肤的几何形貌及力学特点，应用粗糙表面接触力学理论，建立织物与皮肤相互作用的分形接触摩擦模型，研究在织物表面质地的触觉传感中皮肤层的机械响应规律。其次，展开人体皮肤和触觉仿生皮肤关于织物的摩擦触觉实验，研究在表面质地的触觉传感中仿生皮肤的刺激响应规律、皮肤层的生物摩擦力学规律及心理物理学规律，并结合指尖不同触觉感受体的神经生理学特点提出相应的换能调制关系。最后，把上述研究结果应用于构建织物-皮肤-触觉感受体三者之间的神经力学耦合模型，进行数值仿真，分析不同触觉感受体对接触刺激的几何及材料信息、时间及空间信息的传递转换规律，揭示表面质地在触觉传感中的编码模式。研究成果可为触觉交互技术、触觉功能训练及修复、品牌保护等提供重要技术支撑和理论支持。

本课题采用感官评价实验、触摸摩擦信号客观测试实验和触摸仿真相结合的研究方法，展开实验与数值分析互补证明，推动了对织物类材料触觉质感的认知机理的深入认识。一方面以基于织物/指尖摩擦振动信号的触觉再现技术为出发点，围绕振动反馈刺激的经济性、高效性和数字化，结合触觉感受体的振动刺激响应特性，建立以降维算法为核心的时频分析技术，揭示应用该技术提取的摩擦振动信息与织物结构特性之间的协同变化规律，确定表征不同简单平纹机织物粗糙感和柔软感的信号振动区间，为实现简单平纹机织物表面触觉质地的虚拟振动再现技术奠定了基础；另一方面采用在感官评价实验中选用的纹理特征参数化变化的织物材料，通过对比皮肤接触这些材料时的感受器神经元活动强度和触觉评价值之间的一致性，确定了相应的感受器神经元网络诱发神经活动与材料刺激特征的非线性神经力学关系，且发现感受器的活动强度在统计意义上能编码经心理物理实验所确定的物理刺激量变化。这些结果将推动触觉技术和触觉设备的发展及应用，可把织物触感形成的神经力学机制应用于深入探索人机交互材料及器件设计中的神经生理学原理，推动高品质、高附加值的智慧型纺织品的开发，以此实现织物表面触觉质感的虚拟再现提供了方法指导，将推动织物表面触觉质地虚拟再现技术的发展。当然，本课题尚未探索物理刺激丰富的纹理材料在皮肤接触材料表面诱发神经活动过程中的相互影响，以及热、触觉在材料质地认识中的相互作用关系，特别是结合初级认知构建传感-调制-认知网络有待进一步深入研究。