基于热电效应的柔性电子皮肤温觉仿生设计

BIONIC DESIGN OF FLEXIBLE ELECTRONIC SKIN TEMPERATURE SENSATION BASED ON THERMOELECTRIC EFFECT

张澎祥

11849282

硕士

材料工程领域工程

刘玮书

2020-05-28

2020-07-20

哈尔滨工业大学

深圳

电子皮肤是通过结构和功能设计模拟人体皮肤进行感知外界压力、光照、温度和湿度的功能性器件，是实现人机交互的重要媒介。其中，温度是自然界中重要的物理量，已有研究者对电子皮肤的温度传感进行研究，然而鲜有人对假肢进行系统的温觉研究。当前的假肢已经能够实现灵敏的机械操作，但由于其材料和结构特性，欠缺舒适度。为提高假肢在使用者中的接受度和实用性，本文提出在假肢表面进行电子皮肤的温觉仿生设计，以解决针对假肢表面坚硬冰冷的问题。由于人体的温觉系统包括温觉感知和体温调节，因此在此基础上分别在温度传感和温度调控方面进行设计。具体如下：制备了基于二维弹簧结构的热电偶作为假肢表面的温度传感器。设计了不同曲率半径的二维弹簧结构，然后加工出相应形状的掩模版，最终用磁控溅射的方式将测温阵列制备于柔性基底上，并用聚二甲基硅氧烷（PDMS）作为封装材料，制备出了柔性热电偶型温度传感器。为提高热电偶的测温准确性和响应速度，参考人体纤毛结构，在测温点上连接上高导热的铜丝作为仿生纤毛。实验结果证明，柔性纤毛仿生热电偶能够识别0.02 °C 的热源温度变化，其灵敏度为41.25 uV/K，且温度传感阵列具有良好的温度响应，能够分辨出环境或物体的温度分布。设计了基于柔性热电器件的温度调控器件，该温度调控器件由位于顶端的相变储热层和位于底端的柔性热电器件构成。根据人体对温度的感觉，选用相变点为35 °C 的石蜡为温度调控器件提供过热保护，但石蜡液化时由于冷却速度不均而出现柔性结构失稳现象。为了满足电子皮肤对于柔性和结构稳定性的要求，本论文提出了由导热胶泡沫和石蜡构成的复合柔性结构，设计了多孔导热胶为石蜡提供了支持的框架结构。本文系统地研究在模拟复杂环境下，相变层厚度、环境温度、风速和主动方式温度调控等对温度调控器件性能的影响。实验结果表明主动方式和被动方式结合的温度调控器件能够使器件表面温度都处于舒适区之中，其温度调控曲线与人体的体温调节曲线趋势吻合，适合实现假肢表面的温度调控

Electronic skin is a functional device that simulates human skin perception of external pressure, light, temperature and humidity through structural and functional design, and is an important medium for human-computer interaction. Temperature is an important physical quantity in nature. Researchers have studied the temperature sensing of electronic skin, while few have systematically studied the temperature perception of artificial limbs. Current prosthetics are capable of sensitive mechanical operation, but lack comfort due to their material and structural properties. In order to improve the acceptability and practicability of the artificial limb, this paper proposes a biomimetic design of electronic skin temperature on the surface of the artificial limb, so as to solve the problem of hard and cold surface of the artificial limb. Based on the above background, this paper carries out the thermal bionic design of the electronic skin of the prosthesis, and realizes the temperature sensing and temperature regulation of the prosthesis for complex environments.A thermocouple based on a two-dimensional spring structure was prepared as a temperature sensor on the surface of the prosthesis. A two-dimensional spring structure with different curvature radii was designed, and then a mask of the corresponding shape was machined. Finally, the temperature array was prepared on the flexible substrate by magnetron sputtering, and the flexible thermocouple temperature sensor was prepared by using polydimethylsiloxane (PDMS) as the packaging material. In order to improve the response speed and sensitivity of thermocouple, copper wire with high thermal conductivity was connected to the temperature measuring point as bionic cilia, referring to the cilia structure of human body. The experimental results show that the bionic thermocouple of the flexible cilia can identify the temperature change of the heat source at 0.02 °C, and its sensitive is 41.25 V/K, and the temperature sensor array has a good temperature response signal, and can distinguish the temperature distribution of the environment or objects.A temperature-regulated device based on a flexible thermoelectric device is designed, which consists of a phase change thermal reservoir at the top and a flexible thermoelectric device at the bottom. According to the body perception of temperature, paraffin with phase change point of 35 °C is selected to provide overheating protection for temperature control devices. During paraffin liquefaction, the instability of the flexible structure appears due to the uneven cooling rate. In order to meet the requirements of flexibility and structural stability of electronic skin, a composite flexible structure composed of foam and paraffin is proposed in this paper. In this paper, the effects of phase change layer thickness, ambient temperature, wind speed and active temperature regulation on the performance of temperature control devices are systematically studied. The experimental results show that the temperature-regulated device combining active mode and passive mode can make the surface temperature of the device in the comfort zone, and its temperature control curve is consistent with the trend of the body temperature control curve, which is suitable for the surface temperature control of the prosthesis.

电子皮肤 热电效应 温度传感 温度调控 柔性 相变材料

electronic skin thermoelectric effect temperature sensing temperature regulation flexibility phase change material

中文

联合培养

南方科技大学

张澎祥. 基于热电效应的柔性电子皮肤温觉仿生设计[D]. 深圳. 哈尔滨工业大学,2020.