人手皮肤因其内部机械感受器的巧妙配合而具有强大的触压觉功能，研究人手皮肤的触压觉仿生学机理对触压觉传感器的研究具有十分重要的作用。在智能机器人技术领域，机器人手通过触压觉传感器来感知外界压力刺激并对刺激做出有效的反应。目前智能机器人的视觉和听觉系统都已经非常成熟，相对于视觉和听觉而言，触压觉传感方面的研究还不够完善。因此，研究一种能够模仿人手皮肤的柔性触压觉传感器具有非常重要的现实意义。

目前，国内外关于人手皮肤的触压觉仿生学机理有不少研究，研究成果也具有非常重要的科研价值。但是，从触压觉传感器研究的角度对人手皮肤的触压觉仿生学机理的研究较少。而且国内外在触压觉传感器方面的研究还不够成熟。例如，目前的触觉传感器虽然检测精度较高，但其测量范围较小；压觉传感器虽然测量范围较大，但其测量精度不高，这两种传感器都难以实现对外界压力刺激的高精度大范围测量，即实现触觉和压觉的同时模仿。针对此问题，结合对人手皮肤的结构以及皮肤机械感受器的研究，本文基于PDMS弹性材料和平行极板电容原理提出了一种具有三层结构的多尺度柔性触压觉传感器。

本文首先论述了柔性触压觉传感器的选题背景及意义，调研了当前国内外对于人手皮肤触压觉感知特性、柔性触觉传感器、柔性压觉传感器以及多觉传感器的研究现状，在此基础上提出了一种新型的仿人手皮肤的柔性触压觉传感器。然后从皮肤的结构、人手皮肤触压觉单元、人手指尖皮肤对刺激的感知过程、人手皮肤对特定刺激的感知等方面研究了人手皮肤触压觉的仿生学机理，提出了仿人手皮肤的触压觉传感器需要具备的物理性能。接着，基于平行极板电容原理分析了柔性触压觉传感器对微压力的测量原理，分析了传感器模拟人手皮肤触觉和压觉功能的原理。同时模拟人手皮肤的三层结构提出了柔性触压觉传感器的三层结构模型，通过对比分析研究并选取了传感器的衬底材料、电极材料以及介质层材料，通过公式推导完成了传感器的尺寸设计；研究了PDMS弹性材料的旋涂工艺，设计制作出尺寸为10mm×10mm×1.3mm的柔性触压觉传感器单元。最后分析和设计了测量实验，并通过实验验证了该新型柔性触压觉传感器模拟人手皮肤触觉和压觉功能的理论研究，通过最小二乘法对测量结果进行线性拟合，对传感器的灵敏度、线性度和重复性进行计算。

研究结果表明，本文设计的触压觉传感器在实现柔性化的同时具有多尺度的测力范围，可以同时实现触觉和压觉的模拟。触压觉传感器具有0.05-1N和1-30N两个测力范围，在0.05-1N的测量范围内传感器的灵敏度为2.93%/N，线性度为0.03%，重复性误差为2.2%。在1-30N测量范围内传感器的灵敏度为0.08%/N，线性度为0.07%，重复性误差为8.7%。传感器的力分辨率可达0.01N，传感器的空间分辨率达到2mm。

本文研究的柔性触压觉传感器具有柔性化、微型化、高空间分辨率、多尺度测量范围、多测力灵敏度等特点，传感器能够实现对微压力的高精度大范围测量，能够模拟人手皮肤的触觉和压觉功能。本文设计的柔性触压觉传感器在智能机器人触压觉感知系统方面具有巨大的潜在应用价值。

The human skin has a strong tactile-pressure function because of its internal mechanical receptors, so the research on the bionic mechanism of human skin has a very important application in the study of tactile-pressure sensor. In the field of intelligent robotic technology, the robot hands perceive the external pressure stimulation and make the effective response to the stimulation through the tactile-pressure sensor. At present, the visual and auditory systems of intelligent robots are very mature, but the research on tactile-pressure sensing is not perfect. So it is of great practical significance to study the flexible tactile-pressure sensor which can imitate human skin.

 

At present, there are a lot of researches on the mechanism of skin tactile-pressure bionics at home and abroad, and the results also have very important research value. However, From the research standpoint of tactile-pressure sensor, the research on the bionic mechanism of human hand is less. At home and abroad, the research on tactile-pressure sensor is not mature enough. For example, although the tactile sensor has high measurement accuracy, its measurement range is small. Although the pressure sensor has large measurement range, its measurement accuracy is not high. The two sensors are difficult to achieve both high-precision and large-scale measurement to external pressure stimulation, that is, it’s difficult to achieve tactile and pressure imitate at the same time. In this paper, combined with the study of the structure of human skin and the skin mechanical receptors, a multi-scale flexible tactile-pressure sensor with three-layer structure was proposed based on PDMS and the principle of parallel plate capacitance.

 

In this thesis, we discussed the research background and the research significance of the tactile-pressure sensor firstly. And we studied the research status of the flexible tactile sensor, the flexible pressure sensor and the multi-sensory sensor. On this basis, a new flexible tactile-pressure sensor based on parallel plate capacitance principle is proposed. And then we studied tactile-pressure bionic mechanism of the human skin from the structure of the skin, the tactile-pressure receptors of human skin, the perception process of the fingertips skin to stimulates, the perception of human skin to the specific stimulus, and we proposed the physical properties of the tactile-pressure sensors imitating the human skin. Then, based on the parallel plate capacitance，the principle of the sensor was analyzed. Simulating the three-layer structure of the human skin, we proposed the three-layer structure model of the flexible tactile-pressure sensor. We ed the substrate material, the electrode material and the dielectric layer of the sensor, and then the design of the sensor was carried out by formula derivation. We studied the spin-coating process of the PDMS elastic material. The flexible tactile-pressure sensor unit with the size of 10mm×10mm×1.3mm was designed. Finally, we designed the measurement experiment. The experimental results show that the new flexible tactile-pressure sensor can simulate the tactile and pressure feel of human skin, and the least squares method is used to linearly fit the measurement results. We discussed the sensitivity, linearity and repeatability of the tactile-pressure sensor.

 

The results show that the tactile-pressure sensor we designed has the two force ranges of 0.05-1N and1-30N. And the sensor can simulate the tactile and pressure feel at the same time. In the measurement range of 0.05-1N, the sensitivity of the sensor is 2.93%/N, the linearity of the sensor is 0.03% and the repeatability error is about 2.2%. In the measurement range of 1-30N, the sensitivity of the sensor is 0.08%/N, the linearity of the sensor is 0.07% and the repeatability error is about 8.7%. The force resolution of the sensor can reach 0.01N, and the spatial resolution of the sensor is 2mm.

 

In this thesis, the flexible tactile-pressure sensor has the acteristics of flexibility, miniaturization, high spatial resolution, multi-scale measurement range and multi-force sensitivity. The sensor can realize high-precision and large range of measurement while measuring micro-pressure, and can simulate tactile and pressure function of the human skin. The flexible tactile pressure sensor designed in this paper has great potential application value in the intelligent robot perception system.

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