材料弹性对摩擦触觉感知的影响研究

Influence of Elastic Properties of Material on Tactile Perception

材料弹性是影响触觉感知的物理属性之一,从皮肤的“感”和大脑的“知”系统研究材料弹性对触感的影响规律具有重要意义。通过对手指触摸不同弹性特征表面的摩擦、振动信号以及激发的触感脑电信号进行特征参数提取,建立了材料弹性模量E与触感特征参数的关系,实现了弹性表面触感的部分量化表征。结果显示:手指触摸橡胶材料的摩擦力以滞后摩擦分量为主;手指触摸陶瓷和塑料材料时滞后摩擦和黏着摩擦共同影响表面接触摩擦力。相关性分析显示材料E与手指触摸材料的摩擦因数μ、振动频谱最大幅值A_(max)、振动信号的递归参数角线长度均值L和垂直线段长度均值TT均呈负相关,表明材料E越小,振动系统的稳定性越差,复杂度越高。大脑触觉感知的加工时间为触摸开始后的200~400 ms之间,弹性触感激活的脑区主要是大脑中后部的顶叶区及枕叶区;相关性分析显示材料E和触感脑电P300峰值呈正相关,说明材料E越低,激发的大脑神经元兴奋度和注意力越低。手指触摸振动信号A_(max)与触感脑电信号的P300幅值负相关,表明触觉感受体的近端机械刺激与大脑的认知相关联。触摸过程的μ、A_(max)、 L、 TT、和P300峰值与材料E具有明显的关联性,可作为表征材料触摸弹性的特征参数。

Elasticity is one of the important physical properties that affect the tactile perception of human.It is significant to systematically study the influences of elastic properties of material on tactile perception from finger friction to the brain response.The characteristic parameters are extracted from the friction,vibration,and event-related potentials(ERP) signals when finger touched different elastic surfaces.The relationship between surface elasticity and tactile characteristic parameters is established,and the tactile sensation of elastic surface is partially quantized.The results show that during touching rubber the friction force of finger is mainly hysteresis friction,while during touching ceramics and plastics the friction force of finger is formed by hysteresis friction and adhesive friction.The correlation analysis showed that the elastic modulus is negatively correlated with friction coefficient μ,the maximum amplitude of vibration signal A_(max),the mean diagonal line length L,and the mean vertical line length TT of the recursive parameters of vibration signal,indicating that the smaller the elastic modulus is,the worse the stability and the higher the complexity of the vibration system are.The processing time of tactile perception in the brain is between 200 ms and 400 ms after the touching,and the brain regions activated by elastic are mainly the parietal and occipital lobes of the brain.The correlation analysis showed that the elastic modulus of the material is positively correlated with the peak value of P300,indicating that the lower the elastic modulus of the material is,the lower the excitability and attention of brain neurons are stimulated.The maximum amplitude of finger vibration signal is negatively correlated with the P300 peak value,indicating that the mechanical stimulation of tactile receptor is correlated with the cognition of brain.μ,A_(max),L,TT,and P300 peak of tactile ERP signal are significantly correlated with elastic modulus of materials,and can be used as parameters to characterize the tactile elasticity of materials.