技术领域Technical Field
本发明涉及光纤传感与机器人仿生手指传感技术领域，特别是涉及一种基于光纤布拉格光栅的仿生指尖传感器。The invention relates to the technical field of optical fiber sensing and robot bionic finger sensing, and in particular to a bionic fingertip sensor based on optical fiber Bragg grating.
背景技术Background Art
人类手指具有感知各种物体的能力，并能够灵巧地操纵它们，与周围环境互动，这激发了大量触觉传感器的产生。触觉感知是机器人感知周围环境的不可替代的信息来源，是促进机器人实现灵巧操作和精确控制的基础。因此，机器人手指触觉传感器的研究和开发得到了广泛的关注。Human fingers have the ability to sense various objects, manipulate them deftly, and interact with the surrounding environment, which has inspired the creation of a large number of tactile sensors. Tactile perception is an irreplaceable source of information for robots to perceive their surroundings and is the basis for promoting robots to achieve dexterous manipulation and precise control. Therefore, the research and development of robot finger tactile sensors has received widespread attention.
海洋是一个非结构化的环境，有着高环境压力、盐水腐蚀、低光照等恶劣条件。在复杂和非结构化的环境中，机器人的指尖需要触觉传感器来获取诸如接触力、表面粗糙度、滑移等信息。目前一代的水下机器人末端执行器只能实现打开或关闭的运动，不能感知或控制接触力。试图抓取物体时往往会由于不知情地施加过度的接触力而对物体造成伤害。如果抓取力和物体变形是可控的，这将对脆弱物体的取样操作非常有利。因此，研究触觉感知技术来获取水下物体的接触状态、表面特征、物理属性对于提高水下机器人的智能性具有重要意义。The ocean is an unstructured environment with harsh conditions such as high environmental pressure, salt water corrosion, and low light. In complex and unstructured environments, the robot's fingertips need tactile sensors to obtain information such as contact force, surface roughness, and slip. The current generation of underwater robot end effectors can only achieve opening or closing movements and cannot sense or control contact forces. When trying to grasp an object, it often causes damage to the object due to unknowingly applying excessive contact force. If the grasping force and object deformation are controllable, this will be very beneficial for sampling operations of fragile objects. Therefore, studying tactile sensing technology to obtain the contact state, surface characteristics, and physical properties of underwater objects is of great significance to improving the intelligence of underwater robots.
静水压力是指静态液体在密闭储罐中任意给定高度所施加的压力，它对许多不同的行业和应用都是非常重要的信息。在海洋中，需要测量海水压力，以确定仪器设备的具体深度。传统的静水压力传感器一般采用应变计或压阻传感器作为传感元件，由于存在电磁干扰（EMI），电噪声和电磁干扰会引起信号失真，降低灵敏度，引起信号漂移，导致信号损失，引起串扰等。Hydrostatic pressure refers to the pressure exerted by a static liquid at any given height in a closed tank. It is very important information for many different industries and applications. In the ocean, the seawater pressure needs to be measured to determine the specific depth of the instrument. Traditional hydrostatic pressure sensors generally use strain gauges or piezoresistive sensors as sensing elements. Due to the presence of electromagnetic interference (EMI), electrical noise and electromagnetic interference can cause signal distortion, reduce sensitivity, cause signal drift, lead to signal loss, cause crosstalk, etc.
目前，已经有电阻、电容、压电、光学和光弹性等技术来作为触觉传感器的传感元件。当传感器组装成机械手时，将面临小型化难、厚度大、电线多、重量大等问题。此外，触觉传感器通过物理交互获取信息，这就带来了鲁棒性的问题。感知物体相互作用的能力在海洋中非常重要，这要求执行器具有稳定的电气和机械部件来感知和响应环境。At present, there are technologies such as resistors, capacitors, piezoelectrics, optics, and photoelasticity as sensing elements of tactile sensors. When the sensor is assembled into a manipulator, it will face problems such as difficulty in miniaturization, large thickness, many wires, and heavy weight. In addition, tactile sensors obtain information through physical interactions, which brings up the problem of robustness. The ability to sense the interaction of objects is very important in the ocean, which requires the actuator to have stable electrical and mechanical components to sense and respond to the environment.
需要说明的是，在上述背景技术部分公开的信息仅用于对本申请的背景的理解，因此可以包括不构成对本领域普通技术人员已知的现有技术的信息。It should be noted that the information disclosed in the above background technology section is only used for understanding the background of the present application, and therefore may include information that does not constitute prior art known to ordinary technicians in the field.
发明内容Summary of the invention
本发明的主要目的在于解决上述背景技术中存在的问题，提供一种基于光纤布拉格光栅的仿生指尖传感器，能够将感知的正压力与摩擦力进行解耦，有效提高指尖接触力和摩擦力的测量准确性。The main purpose of the present invention is to solve the problems existing in the above-mentioned background technology and to provide a bionic fingertip sensor based on fiber Bragg grating, which can decouple the sensed normal pressure from the friction force and effectively improve the measurement accuracy of the fingertip contact force and friction force.
进一步地，提供一种基于光纤布拉格光栅的仿生指尖传感器，能够同时准确测量水下静水压、温度、接触力、滑移。Furthermore, a bionic fingertip sensor based on fiber Bragg grating is provided, which can accurately measure underwater hydrostatic pressure, temperature, contact force and slip simultaneously.
为实现上述目的，本发明采用以下技术方案：To achieve the above object, the present invention adopts the following technical solutions:
一种基于光纤布拉格光栅的仿生指尖传感器，包括骨架结构、柔性指套和光纤，所述柔性指套套在所述骨架结构的外部，所述柔性指套的指尖正压力接触区相对于非接触区设置有凸起，所述光纤引到所述柔性指套中，并在所述柔性指套中平滑弯曲布置，从所述指尖正压力接触区延伸至所述非接触区；所述光纤还设置有第一至第二光纤布拉格光栅，其中，第一光纤布拉格光栅设置在所述柔性指套的所述指尖正压力接触区后方的非接触区，以形成滑移感知区，第二光纤布拉格光栅设置在所述柔性指套的指尖正压力接触区。A bionic fingertip sensor based on fiber Bragg gratings comprises a skeleton structure, a flexible finger cuff and an optical fiber, wherein the flexible finger cuff is sleeved on the outside of the skeleton structure, a protrusion is arranged in a fingertip positive pressure contact area of the flexible finger cuff relative to a non-contact area, the optical fiber is led into the flexible finger cuff and smoothly bent and arranged in the flexible finger cuff, extending from the fingertip positive pressure contact area to the non-contact area; the optical fiber is also provided with first and second fiber Bragg gratings, wherein the first fiber Bragg grating is arranged in the non-contact area behind the fingertip positive pressure contact area of the flexible finger cuff to form a slip sensing area, and the second fiber Bragg grating is arranged in the fingertip positive pressure contact area of the flexible finger cuff.
进一步地，所述骨架结构包括刚性主骨架、刚性副骨架和隔膜，所述刚性主骨架具有第二腔室，所述光纤延伸到所述第二腔室，所述刚性副骨架具有与外界连通的第三腔室，所述第二腔室和所述第三腔室之间由所述隔膜分隔，所述光纤在所述第二腔室内平滑弯曲延伸并连接在所述隔膜上，所述光纤上至少设置有第三至第四光纤布拉格光栅，其中，第三光纤布拉格光栅设置在靠近所述隔膜的边缘，第四光纤布拉格光栅设置在所述隔膜的中心。Furthermore, the skeleton structure includes a rigid main skeleton, a rigid sub-skeleton and a diaphragm, the rigid main skeleton has a second chamber, the optical fiber extends to the second chamber, the rigid sub-skeleton has a third chamber connected to the outside, the second chamber and the third chamber are separated by the diaphragm, the optical fiber smoothly bends and extends in the second chamber and is connected to the diaphragm, and at least third to fourth fiber Bragg gratings are arranged on the optical fiber, wherein the third fiber Bragg grating is arranged near the edge of the diaphragm, and the fourth fiber Bragg grating is arranged at the center of the diaphragm.
进一步地，还包括力隔离管，所述刚性主骨架还具有第一腔室，所述力隔离管固定在第一腔室内，所述力隔离管内填充软材料，所述光纤穿过所述力隔离管延伸到所述第二腔室；所述光纤上还设置有第五光纤布拉格光栅，所述第五光纤布拉格光栅设置在所述力隔离管内。Furthermore, it also includes a force isolation tube, the rigid main skeleton also has a first chamber, the force isolation tube is fixed in the first chamber, the force isolation tube is filled with soft material, the optical fiber passes through the force isolation tube and extends to the second chamber; a fifth fiber Bragg grating is also arranged on the optical fiber, and the fifth fiber Bragg grating is arranged in the force isolation tube.
进一步地，所述力隔离管为毛细钢管。Furthermore, the force isolation tube is a capillary steel tube.
进一步地，所述第一腔室内在所述力隔离管外填充软材料。Furthermore, the first chamber is filled with soft material outside the force isolation tube.
进一步地，所述光纤固定在所述力隔离管的两端。Furthermore, the optical fiber is fixed at two ends of the force isolation tube.
进一步地，所述隔膜为圆形。Furthermore, the diaphragm is circular.
进一步地，所述隔膜的周缘设置有通孔，所述刚性副骨架上的多个固定柱通过所述通孔装入所述刚性主骨架上的装配孔，或者所述刚性主骨架上的多个固定柱通过所述通孔装入所述刚性副骨架上的装配孔，使所述刚性主骨架、所述隔膜与所述刚性副骨架紧密贴合。Furthermore, the periphery of the diaphragm is provided with through holes, and a plurality of fixing columns on the rigid sub-skeleton are installed into the assembly holes on the rigid main frame through the through holes, or a plurality of fixing columns on the rigid main frame are installed into the assembly holes on the rigid sub-skeleton through the through holes, so that the rigid main frame, the diaphragm and the rigid sub-skeleton are tightly fitted.
所述刚性副骨架的外端为圆弧面。The outer end of the rigid sub-frame is an arc surface.
还包括连接件，所述连接件的第一端面与所述刚性主骨架的远离所述隔膜的端面相连，所述光纤穿过所述连接件上的光纤过孔进入所述第一腔室，所述连接件朝外的第二端面设置有带外螺纹的圆柱凸起，所述圆柱凸起用于将所述连接件集成安装到水下执行器上。It also includes a connecting piece, a first end face of the connecting piece is connected to the end face of the rigid main frame away from the diaphragm, the optical fiber passes through the optical fiber via hole on the connecting piece into the first chamber, and the second end face of the connecting piece facing outward is provided with a cylindrical protrusion with an external thread, and the cylindrical protrusion is used to integrate the connecting piece into the underwater actuator.
与现有技术相比，本发明具有如下有益效果：Compared with the prior art, the present invention has the following beneficial effects:
本发明提供的基于光纤布拉格光栅的仿生指尖传感器，The bionic fingertip sensor based on fiber Bragg grating provided by the present invention,
本发明将光纤引到柔性指套中并在柔性指套中平滑弯曲布置，从柔性指套的指尖正压力接触区延伸至非接触区，并在非接触区和指尖正压力接触区分别设置第一和第二光纤布拉格光栅，同时，通过柔性指套的指尖正压力接触区相对于非接触区的软材料凸起设计，使得指尖正压力接触区上施加的正压力不会对软材料的滑移感知区产生影响，而滑动产生的剪切力又会对滑移感知区产生形变，籍此可以将正压力与摩擦力进行解耦，从而有效提高了仿生指尖传感器对指尖接触力和摩擦力的分辨能力和测量准确性。The present invention introduces an optical fiber into a flexible finger sleeve and arranges the optical fiber in a smooth bending manner in the flexible finger sleeve, extends from a fingertip positive pressure contact area of the flexible finger sleeve to a non-contact area, and respectively arranges a first and a second fiber Bragg grating in the non-contact area and the fingertip positive pressure contact area. At the same time, by designing a soft material protrusion in the fingertip positive pressure contact area of the flexible finger sleeve relative to the non-contact area, the positive pressure applied to the fingertip positive pressure contact area will not affect the slip sensing area of the soft material, and the shear force generated by the sliding will cause deformation in the slip sensing area, thereby decoupling the positive pressure from the friction force, thereby effectively improving the resolution capability and measurement accuracy of the bionic fingertip sensor for the fingertip contact force and the friction force.
进一步的方案中，柔性指套的骨架结构设计包括刚性主骨架、刚性副骨架和隔膜，工作时，液体可以进入所述刚性副骨架的第三腔室中，在水下环境中，所述隔膜的第一端面受到的气压与所述隔膜的第二端面受到的静水压形成压力差，得到所述隔膜的变形，引起位于所述隔膜第一端面的第三、第四光纤布拉格光栅的应变，得到两个FBG的光信号波长漂移，由于这两个FBG分别布置在靠近隔膜的边缘和隔膜的中心，在静水压作用下，从隔膜的边缘到中心，径向应变由负值逐渐减小到零再变为正值，导致第三FBG的波长漂移是温度变化与正径向应变的叠加，第四FBG的波长漂移是温度变化与负径向应变的叠加，利用本发明的传感器采集到第三FBG和第四FBG的波长后，将二者的波长漂移相减，既消除了温度对FBG的影响，又放大了静水压力对隔膜产生的波长漂移信号。由此，本发明的基于光纤布拉格光栅的仿生指尖传感器通过内外腔室、隔膜、光纤及其布拉格光栅的配合设计，并通过在隔膜中心和靠近隔膜边缘的两个布拉格光栅布置，既对温度进行了补偿，又增大了传感器测量水压的灵敏度。In a further solution, the skeleton structure design of the flexible finger sleeve includes a rigid main skeleton, a rigid sub-skeleton and a diaphragm. When working, liquid can enter the third chamber of the rigid sub-skeleton. In an underwater environment, the air pressure on the first end face of the diaphragm and the hydrostatic pressure on the second end face of the diaphragm form a pressure difference, resulting in deformation of the diaphragm, causing strains of the third and fourth fiber Bragg gratings located on the first end face of the diaphragm, and obtaining wavelength drifts of optical signals of the two FBGs. Since the two FBGs are arranged near the edge and the center of the diaphragm, respectively, under the action of hydrostatic pressure, from the edge to the center of the diaphragm, the radial strain gradually decreases from a negative value to zero and then becomes a positive value, resulting in the wavelength drift of the third FBG being the superposition of temperature change and positive radial strain, and the wavelength drift of the fourth FBG being the superposition of temperature change and negative radial strain. After the wavelengths of the third FBG and the fourth FBG are collected by the sensor of the present invention, the wavelength drifts of the two are subtracted, which not only eliminates the influence of temperature on the FBG, but also amplifies the wavelength drift signal generated by the hydrostatic pressure on the diaphragm. Therefore, the bionic fingertip sensor based on fiber Bragg grating of the present invention not only compensates for temperature but also increases the sensitivity of the sensor in measuring water pressure through the coordinated design of inner and outer chambers, diaphragms, optical fibers and their Bragg gratings, and the arrangement of two Bragg gratings at the center of the diaphragm and near the edge of the diaphragm.
进一步地，本发明提供一种基于光纤布拉格光栅的多模态感知仿生指尖传感器，能够同时准确测量水下静水压、温度、接触力、滑移。Furthermore, the present invention provides a multi-modal sensing bionic fingertip sensor based on fiber Bragg grating, which can accurately measure underwater hydrostatic pressure, temperature, contact force, and slippage simultaneously.
多模态感知能力：本发明集成了基于光纤布拉格光栅（Fiber Bragg Grating，FBG）的传感原理，能够在一个传感器中实现对水下静水压、温度、接触力和滑移的多模态智能感知，这种单一传感原理的集成避免了多传感器系统的复杂性和信号耦合问题。Multimodal sensing capability: The present invention integrates the sensing principle based on Fiber Bragg Grating (FBG), which can realize multimodal intelligent sensing of underwater hydrostatic pressure, temperature, contact force and slip in one sensor. The integration of this single sensing principle avoids the complexity and signal coupling problems of multi-sensor systems.
高度集成化设计：通过将FBG传感器集成到仿生人类指尖结构的软执行器中，本发明易于集成到水下执行器末端，提供了一种小型化、易于安装的解决方案。Highly integrated design: By integrating FBG sensors into soft actuators that mimic the structure of human fingertips, the present invention can be easily integrated into the end of underwater actuators, providing a miniaturized and easy-to-install solution.
耐腐蚀与抗电磁干扰：通过采用光纤传感技术，本发明的传感器具有优异的耐腐蚀性能和抗电磁干扰能力，适合在水下等恶劣环境中使用。Corrosion resistance and anti-electromagnetic interference: By adopting optical fiber sensing technology, the sensor of the present invention has excellent corrosion resistance and anti-electromagnetic interference capabilities, and is suitable for use in harsh environments such as underwater.
温度自补偿机制：通过内外腔室、隔膜、光纤及其布拉格光栅的巧妙配合设计，并在隔膜的中心和靠边缘处分别布置FBG，不仅实现了水下静水压测量，而且利用两个FBG的波长漂移差异同时实现了温度补偿和测压力灵敏度的增强，提高了测量的准确性和稳定性。Temperature self-compensation mechanism: Through the ingenious coordination of the inner and outer chambers, diaphragms, optical fibers and their Bragg gratings, and the arrangement of FBGs at the center and near the edge of the diaphragm, not only the underwater hydrostatic pressure measurement is realized, but also the wavelength drift difference of the two FBGs is used to simultaneously realize temperature compensation and enhance the pressure measurement sensitivity, thereby improving the accuracy and stability of the measurement.
高灵敏度与快速响应：本发明的结构设计实现了对静水压力的高灵敏度测量，同时光纤传感器本身具有快速的响应速度和高灵敏度。High sensitivity and fast response: The structural design of the present invention realizes high-sensitivity measurement of hydrostatic pressure, and the optical fiber sensor itself has fast response speed and high sensitivity.
封装技术优化：采用合理的封装技术，将FBG5置于力隔离管内并填充软材料，有效避免了力对温度测量FBG的影响，确保了温度测量的准确性。Packaging technology optimization: By adopting reasonable packaging technology, FBG5 is placed in a force isolation tube and filled with soft materials, which effectively avoids the influence of force on the temperature measurement FBG and ensures the accuracy of temperature measurement.
解耦设计：通过指尖正压力接触区相对于非接触区的软材料凸起设计，并在两个区内分别设置FBG，实现了正压力与摩擦力的有效解耦，提高了传感器对指尖接触力和摩擦力的区分能力和测量准确性。Decoupling design: By designing a soft material protrusion in the fingertip positive pressure contact area relative to the non-contact area and setting FBGs in the two areas respectively, effective decoupling of positive pressure and friction is achieved, thereby improving the sensor's ability to distinguish between fingertip contact force and friction and its measurement accuracy.
适用于复杂环境：本发明特别适合于水下复杂环境的智能感知，能够在非结构化环境中实现精确的触觉反馈和环境检测。Applicable to complex environments: The present invention is particularly suitable for intelligent perception of complex underwater environments, and can achieve accurate tactile feedback and environmental detection in unstructured environments.
易于实现分布式传感：利用FBG的分布式特性，本发明可以方便地扩展为多点测量，提高了传感器的应用灵活性和测量范围。Easy to implement distributed sensing: By utilizing the distributed characteristics of FBG, the present invention can be easily expanded to multi-point measurement, thereby improving the application flexibility and measurement range of the sensor.
低传输损耗：光纤传感器的传输损耗低，有助于长距离的数据传输和监控，适合深海探测等应用场景。Low transmission loss: Fiber optic sensors have low transmission loss, which facilitates long-distance data transmission and monitoring and is suitable for application scenarios such as deep-sea exploration.
在海洋环境中，基于光纤布拉格光栅FBG的传感技术与传统的电气传感技术相比具有显著的优势：（1）耐腐蚀，（2）抗电磁干扰，（3）分布式传感，（4）体积小，（5）传输损耗低。由于FBG的温度交叉灵敏性，FBG传感器的波长偏移通常受到温度和应变参数的叠加影响。而综合上述优点，本发明不仅提升了水下机器人的智能性，还为深海探测、安全人机交互以及非结构化环境的智能感知与控制提供了有效的技术支持。In the marine environment, the sensing technology based on fiber Bragg grating (FBG) has significant advantages over the traditional electrical sensing technology: (1) corrosion resistance, (2) anti-electromagnetic interference, (3) distributed sensing, (4) small size, and (5) low transmission loss. Due to the temperature cross-sensitivity of FBG, the wavelength shift of FBG sensors is usually affected by the superposition of temperature and strain parameters. Combining the above advantages, the present invention not only improves the intelligence of underwater robots, but also provides effective technical support for deep-sea exploration, safe human-computer interaction, and intelligent perception and control of unstructured environments.
本发明实施例中的其他有益效果将在下文中进一步述及。Other beneficial effects of the embodiments of the present invention will be further described below.
附图说明BRIEF DESCRIPTION OF THE DRAWINGS
图1是本发明实施例仿生指尖传感器整体结构示意图；FIG1 is a schematic diagram of the overall structure of a bionic fingertip sensor according to an embodiment of the present invention;
图2是本发明实施例仿生指尖传感器爆炸结构示意图；FIG2 is a schematic diagram of the explosion structure of a bionic fingertip sensor according to an embodiment of the present invention;
图3是本发明实施例仿生指尖传感器光纤配置与FBG的分布示意图；3 is a schematic diagram of the optical fiber configuration and FBG distribution of the bionic fingertip sensor according to an embodiment of the present invention;
图4是本发明实施例仿生指尖传感器中温度传感器FBG的封装结构示意图。FIG. 4 is a schematic diagram of the packaging structure of the temperature sensor FBG in the bionic fingertip sensor according to an embodiment of the present invention.
附图标记：Reference numerals:
柔性指套1、刚性副骨架2、隔膜3、刚性主骨架4、毛细钢管5、软填充物6、连接件7、螺栓8、光纤9、开口11、指尖正压力接触区12、非接触区13、第三腔室20、圆孔21、圆柱体22、圆形通孔31、空心圆孔41、第二腔室42、空心圆柱61、软材料62、螺纹通孔71、中心圆柱孔72、圆柱凸起73、光缆91、第五光纤布拉格光栅（FBG5）92、第四光纤布拉格光栅（FBG4）93、第三光纤布拉格光栅（FBG3）94、第二光纤布拉格光栅（FBG2）95、第一光纤布拉格光栅（FBG1）96。Flexible finger sleeve 1, rigid sub-skeleton 2, diaphragm 3, rigid main skeleton 4, capillary steel tube 5, soft filler 6, connector 7, bolt 8, optical fiber 9, opening 11, fingertip positive pressure contact area 12, non-contact area 13, third chamber 20, circular hole 21, cylinder 22, circular through hole 31, hollow circular hole 41, second chamber 42, hollow cylinder 61, soft material 62, threaded through hole 71, central cylindrical hole 72, cylindrical protrusion 73, optical cable 91, fifth fiber Bragg grating (FBG5) 92, fourth fiber Bragg grating (FBG4) 93, third fiber Bragg grating (FBG3) 94, second fiber Bragg grating (FBG2) 95, first fiber Bragg grating (FBG1) 96.
具体实施方式DETAILED DESCRIPTION
以下对本发明的实施方式做详细说明。应该强调的是，下述说明仅仅是示例性的，而不是为了限制本发明的范围及其应用。The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope and application of the present invention.
需要说明的是，当元件被称为“固定于”或“设置于”另一个元件，它可以直接在另一个元件上或者间接在该另一个元件上。当一个元件被称为是“连接于”另一个元件，它可以是直接连接到另一个元件或间接连接至该另一个元件上。另外，连接既可以是用于固定作用也可以是用于耦合或连通作用。It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for fixing as well as for coupling or communication.
需要理解的是，术语“长度”、“宽度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”、“内”、“外”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本发明实施例和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本发明的限制。It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.
此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括一个或者更多该特征。在本发明实施例的描述中，“多个”的含义是两个或两个以上，除非另有明确具体的限定。In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.
参阅图1至图4，本发明实施例提供一种基于光纤布拉格光栅的仿生指尖传感器，包括骨架结构（其例如可以包括刚性主骨架4和刚性副骨架2）、柔性指套1和光纤9，所述柔性指套1套在所述骨架结构的外部，所述柔性指套1的指尖正压力接触区12相对于非接触区13设置有凸起，所述光纤9引到所述柔性指套1中，并在所述柔性指套1中平滑弯曲布置，从所述指尖正压力接触区12延伸至所述非接触区13；所述光纤9还设置有第一至第二光纤布拉格光栅，其中，第一光纤布拉格光栅（FBG1）96设置在所述柔性指套1的位于所述指尖正压力接触区12后方的非接触区13，以形成滑移感知区，第二光纤布拉格光栅（FBG2）95设置在所述柔性指套1的指尖正压力接触区12。1 to 4 , an embodiment of the present invention provides a bionic fingertip sensor based on fiber Bragg gratings, comprising a skeleton structure (which may include, for example, a rigid main skeleton 4 and a rigid sub-skeleton 2), a flexible finger cuff 1 and an optical fiber 9, wherein the flexible finger cuff 1 is sleeved on the outside of the skeleton structure, a fingertip positive pressure contact area 12 of the flexible finger cuff 1 is provided with a protrusion relative to a non-contact area 13, the optical fiber 9 is led into the flexible finger cuff 1, and smoothly bent and arranged in the flexible finger cuff 1, extending from the fingertip positive pressure contact area 12 to the non-contact area 13; the optical fiber 9 is also provided with first and second fiber Bragg gratings, wherein a first fiber Bragg grating (FBG1) 96 is provided in the non-contact area 13 of the flexible finger cuff 1 located behind the fingertip positive pressure contact area 12 to form a slip sensing area, and a second fiber Bragg grating (FBG2) 95 is provided in the fingertip positive pressure contact area 12 of the flexible finger cuff 1.
本发明将光纤引到柔性指套中并在柔性指套中平滑弯曲布置，从柔性指套的指尖正压力接触区延伸至非接触区，并在非接触区和指尖正压力接触区分别设置第一和第二光纤布拉格光栅，同时，通过柔性指套的指尖正压力接触区相对于非接触区的软材料凸起设计，使得指尖正压力接触区上施加的正压力不会对软材料的滑移感知区产生影响，而滑动产生的剪切力又会对滑移感知区产生形变，籍此可以将正压力与摩擦力进行解耦，从而有效提高了仿生指尖传感器对指尖接触力和摩擦力的分辨能力和测量准确性。The present invention introduces an optical fiber into a flexible finger sleeve and arranges the optical fiber in a smooth bending manner in the flexible finger sleeve, extends from the fingertip positive pressure contact area of the flexible finger sleeve to the non-contact area, and respectively arranges a first and a second fiber Bragg grating in the non-contact area and the fingertip positive pressure contact area. At the same time, by designing a soft material protrusion in the fingertip positive pressure contact area of the flexible finger sleeve relative to the non-contact area, the positive pressure applied to the fingertip positive pressure contact area will not affect the slip sensing area of the soft material, and the shear force generated by the sliding will cause deformation in the slip sensing area, thereby decoupling the positive pressure from the friction force, thereby effectively improving the resolution capability and measurement accuracy of the bionic fingertip sensor for the fingertip contact force and the friction force.
参阅图1至图4，本发明进一步优选的实施例提供一种基于光纤布拉格光栅的多模态感知仿生指尖传感器，包括刚性主骨架4、刚性副骨架2、柔性指套1、隔膜3、光纤9和力隔离管（如毛细钢管5），所述刚性主骨架4具有第一腔室（如空心圆柱61）和第二腔室42，所述力隔离管固定在第一腔室内，所述力隔离管内填充软材料62，来自光缆91的所述光纤9穿过所述力隔离管延伸到所述第二腔室42，所述刚性副骨架2具有与外界连通（如通过圆孔21）的第三腔室20，所述第二腔室42和所述第三腔室之间由所述隔膜3分隔，所述光纤9在所述第二腔室42内平滑弯曲延伸并连接在所述隔膜3上，所述柔性指套1套在所述刚性主骨架4和所述刚性副骨架2的外部，所述柔性指套1的指尖正压力接触区12相对于非接触区13设置有凸起（优选为指肚形），所述光纤9通过所述刚性主骨架4上的引出孔引出到所述柔性指套1中，并在所述柔性指套1中平滑弯曲布置，从所述指尖正压力接触区12延伸至所述非接触区13；所述光纤9上设置有第一至第五光纤布拉格光栅，其中，第一光纤布拉格光栅（FBG1）96设置在所述柔性指套1的非接触区13，第二光纤布拉格光栅（FBG2）95设置在所述柔性指套1的指尖正压力接触区12，第三光纤布拉格光栅（FBG3）94设置在靠近所述隔膜3的边缘，第四光纤布拉格光栅（FBG4）93设置在所述隔膜3的中心，第五光纤布拉格光栅（FBG5）92设置在所述力隔离管内。Referring to Figures 1 to 4, a further preferred embodiment of the present invention provides a multimodal sensing bionic fingertip sensor based on fiber Bragg grating, comprising a rigid main skeleton 4, a rigid sub-skeleton 2, a flexible finger cuff 1, a diaphragm 3, an optical fiber 9 and a force isolation tube (such as a capillary steel tube 5), wherein the rigid main skeleton 4 has a first chamber (such as a hollow cylinder 61) and a second chamber 42, the force isolation tube is fixed in the first chamber, the force isolation tube is filled with a soft material 62, the optical fiber 9 from the optical cable 91 passes through the force isolation tube and extends to the second chamber 42, the rigid sub-skeleton 2 has a third chamber 20 connected to the outside (such as through a circular hole 21), the second chamber 42 and the third chamber are separated by the diaphragm 3, the optical fiber 9 smoothly bends and extends in the second chamber 42 and is connected to the diaphragm 3, and the flexible finger cuff 1 is sleeved on the outside of the rigid main skeleton 4 and the rigid sub-skeleton 2 The fingertip positive pressure contact area 12 of the flexible finger cuff 1 is provided with a protrusion (preferably in the shape of a finger belly) relative to the non-contact area 13, and the optical fiber 9 is led out into the flexible finger cuff 1 through the lead-out hole on the rigid main skeleton 4, and is smoothly bent and arranged in the flexible finger cuff 1, extending from the fingertip positive pressure contact area 12 to the non-contact area 13; the first to fifth fiber Bragg gratings are arranged on the optical fiber 9, wherein the first fiber Bragg grating (FBG1) 96 is arranged in the non-contact area 13 of the flexible finger cuff 1, the second fiber Bragg grating (FBG2) 95 is arranged in the fingertip positive pressure contact area 12 of the flexible finger cuff 1, the third fiber Bragg grating (FBG3) 94 is arranged near the edge of the diaphragm 3, the fourth fiber Bragg grating (FBG4) 93 is arranged in the center of the diaphragm 3, and the fifth fiber Bragg grating (FBG5) 92 is arranged in the force isolation tube.
如图2和图3所示，在优选的实施例中，所述第一腔室内在所述力隔离管外填充有软填充物6。As shown in FIG. 2 and FIG. 3 , in a preferred embodiment, the first chamber is filled with a soft filler 6 outside the force isolation tube.
在优选的实施例中，所述光纤9固定在所述力隔离管的两端。In a preferred embodiment, the optical fiber 9 is fixed at both ends of the force isolation tube.
如图1和图2所示，在优选的实施例中，所述隔膜3为圆形。As shown in FIG. 1 and FIG. 2 , in a preferred embodiment, the diaphragm 3 is circular.
如图2所示，在优选的实施例中，所述隔膜3的周缘设置有圆形通孔31，所述刚性副骨架2上的多个固定柱（如圆柱体22）通过所述圆形通孔31装入所述刚性主骨架4上的装配孔（如空心圆孔41），或者所述刚性主骨架4上的多个固定柱通过所述通孔装入所述刚性副骨架2上的装配孔，使所述刚性主骨架4、所述隔膜3与所述刚性副骨架2紧密贴合。As shown in Figure 2, in a preferred embodiment, a circular through hole 31 is provided on the periphery of the diaphragm 3, and a plurality of fixing columns (such as the cylinder 22) on the rigid sub-skeleton 2 are installed into the assembly holes (such as the hollow circular holes 41) on the rigid main skeleton 4 through the circular through holes 31, or a plurality of fixing columns on the rigid main skeleton 4 are installed into the assembly holes on the rigid sub-skeleton 2 through the through holes, so that the rigid main skeleton 4, the diaphragm 3 and the rigid sub-skeleton 2 are tightly fitted.
如图1至图3所示，在优选的实施例中，所述刚性副骨架2的外端为圆弧面，例如球面。As shown in FIG. 1 to FIG. 3 , in a preferred embodiment, the outer end of the rigid sub-frame 2 is an arc surface, such as a spherical surface.
如图1至图3所示，在优选的实施例中，所述多模态感知仿生指尖传感器还包括连接件7，所述连接件7的第一端面与所述刚性主骨架4的远离所述隔膜3的端面相连，所述光纤9穿过所述连接件7上的光纤9过孔进入所述第一腔室。As shown in Figures 1 to 3, in a preferred embodiment, the multimodal sensing bionic fingertip sensor also includes a connector 7, a first end face of the connector 7 is connected to the end face of the rigid main skeleton 4 away from the diaphragm 3, and the optical fiber 9 passes through the optical fiber 9 via hole on the connector 7 into the first chamber.
如图2至图3所示，在优选的实施例中，所述连接件7朝外的第二端面设置有带外螺纹的圆柱凸起73，所述圆柱凸起73用于将所述连接件7集成安装到水下执行器上。As shown in FIG. 2 and FIG. 3 , in a preferred embodiment, a cylindrical protrusion 73 with an external thread is provided on the second end surface of the connecting member 7 facing outwards, and the cylindrical protrusion 73 is used to integrally mount the connecting member 7 on the underwater actuator.
如图3所示，在优选的实施例中，所述光纤9经过所述柔性指套1的非接触区连接到所述连接件7上。As shown in FIG. 3 , in a preferred embodiment, the optical fiber 9 is connected to the connecting member 7 through the non-contact area of the flexible finger sleeve 1 .
如图1至图4所示，在一些实施例中，多模态感知仿生指尖传感器包括刚性主骨架4、刚性副骨架2、柔性指套1、隔膜3、连接件7、光纤9、毛细钢管5、软填充材料、螺栓8。As shown in Figures 1 to 4, in some embodiments, the multimodal sensing bionic fingertip sensor includes a rigid main frame 4, a rigid sub-frame 2, a flexible finger sleeve 1, a diaphragm 3, a connector 7, an optical fiber 9, a capillary steel tube 5, a soft filling material, and a bolt 8.
所述隔膜3的第一端面与所述刚性主骨架4的第一端面连接，形成空腔，使所述隔膜3的第一端面受到气压。所述隔膜3的第二端面与所述刚性副骨架2贴合，用于将液体引入所述刚性副骨架2的腔体，使所述隔膜3的第二端面受到静水压。The first end face of the diaphragm 3 is connected to the first end face of the rigid main frame 4 to form a cavity, so that the first end face of the diaphragm 3 is subjected to air pressure. The second end face of the diaphragm 3 is in contact with the rigid sub-frame 2 to introduce liquid into the cavity of the rigid sub-frame 2, so that the second end face of the diaphragm 3 is subjected to hydrostatic pressure.
所述刚性副骨架2的圆柱体22插入所述刚性主骨架4的圆柱凹槽（所述刚性副骨架2穿过所述隔膜3与所述刚性主骨架4的第一端面连接），用于固定所述隔膜3。The cylinder 22 of the rigid sub-frame 2 is inserted into the cylindrical groove of the rigid main frame 4 (the rigid sub-frame 2 passes through the diaphragm 3 and is connected to the first end surface of the rigid main frame 4 ) to fix the diaphragm 3 .
所述柔性指套1上设有开口11，所述刚性副骨架2的球面对应开有圆孔21，使液体可以通过圆孔21进入所述刚性副骨架2的腔室中，在水下环境中，所述隔膜3的第一端面受到的气压与所述隔膜3的第二端面受到的静水压形成压力差，得到所述隔膜3的变形。The flexible finger sleeve 1 is provided with an opening 11, and the spherical surface of the rigid sub-skeleton 2 is correspondingly provided with a circular hole 21, so that liquid can enter the chamber of the rigid sub-skeleton 2 through the circular hole 21. In an underwater environment, the air pressure on the first end face of the diaphragm 3 and the hydrostatic pressure on the second end face of the diaphragm 3 form a pressure difference, resulting in deformation of the diaphragm 3.
所述毛细钢管5放置于所述刚性主骨架4第二端的空心圆柱61的中心位置，并用软填充材料填充剩余的空心区域，得到一个毛细钢管保护外壳。The capillary steel tube 5 is placed at the center of the hollow cylinder 61 at the second end of the rigid main frame 4, and the remaining hollow area is filled with soft filling material to obtain a capillary steel tube protective shell.
所述连接件7的第一端面开有螺纹通孔，用所述螺栓8将所述连接件7的第一端面和所述刚性主骨架4的第二端面连接。A threaded through hole is formed on the first end face of the connecting member 7 , and the first end face of the connecting member 7 and the second end face of the rigid main frame 4 are connected by the bolt 8 .
所述柔性指套1与所述刚性主骨架4连接，得到所述指尖传感器的柔性仿生皮肤，在所述柔性指套1按压区受到接触力和摩擦力后，得到所述柔性指套1的变形。The flexible finger sleeve 1 is connected to the rigid main frame 4 to obtain the flexible bionic skin of the fingertip sensor. After the pressing area of the flexible finger sleeve 1 is subjected to contact force and friction force, the flexible finger sleeve 1 is deformed.
所述光纤9通过所述连接件7的中心孔引入到所述刚性主骨架4中，然后所述光纤9穿过所述毛细钢管5并将两端固定在所述毛细钢管5两端，穿过所述毛细钢管5后，所述光纤9在所述刚性主骨架4第一端的空心圆柱中均匀弯曲，将所述光纤9连接到所述隔膜3的第一端面，并通过所述刚性主骨架4的小孔引出到所述柔性指套1中，所述光纤9在所述柔性指套1中规律弯曲。The optical fiber 9 is introduced into the rigid main skeleton 4 through the central hole of the connector 7, and then passes through the capillary steel tube 5 and fixes both ends at the two ends of the capillary steel tube 5. After passing through the capillary steel tube 5, the optical fiber 9 is evenly bent in the hollow cylinder at the first end of the rigid main skeleton 4, and the optical fiber 9 is connected to the first end face of the diaphragm 3, and is led out to the flexible finger sleeve 1 through the small hole of the rigid main skeleton 4, and the optical fiber 9 is regularly bent in the flexible finger sleeve 1.
以下进一步描述本发明具体实施例。The specific embodiments of the present invention are further described below.
作为一种优选的示例，所述的刚性主骨架4整体为圆柱形，以模拟人类手指的外骨骼。所述刚性主骨架4直径为22mm，高度为38mm。按图3中的方向，所述刚性主骨架4的空心圆柱部分从左往右依次为：直径为6mm，高度为10mm的空心圆柱，直径为4mm，高度为3mm的空心圆柱，直径为0.2mm，高度为3mm的空心圆柱，以及直径为16mm，高度为22mm的空心圆柱；所述刚性主骨架4左端面圆周阵列有6个高度为5mm的M2螺纹孔，螺纹孔中心与所述刚性主骨架4左端面圆心的距离为8mm。所述刚性主骨架4右端面圆周阵列有4个直径为1.5mm，高度为5mm的空心圆柱，空心圆柱中心与所述刚性主骨架4右端面圆心的距离为9.5mm。As a preferred example, the rigid main skeleton 4 is cylindrical as a whole to simulate the exoskeleton of human fingers. The rigid main skeleton 4 has a diameter of 22 mm and a height of 38 mm. According to the direction in Figure 3, the hollow cylindrical parts of the rigid main skeleton 4 are, from left to right: a hollow cylinder with a diameter of 6 mm and a height of 10 mm, a hollow cylinder with a diameter of 4 mm and a height of 3 mm, a hollow cylinder with a diameter of 0.2 mm and a height of 3 mm, and a hollow cylinder with a diameter of 16 mm and a height of 22 mm; the left end face circular array of the rigid main skeleton 4 has 6 M2 threaded holes with a height of 5 mm, and the distance between the center of the threaded hole and the center of the left end face of the rigid main skeleton 4 is 8 mm. The right end face circular array of the rigid main skeleton 4 has 4 hollow cylinders with a diameter of 1.5 mm and a height of 5 mm, and the distance between the center of the hollow cylinder and the center of the right end face of the rigid main skeleton 4 is 9.5 mm.
作为一种优选的示例，所述的隔膜3为圆柱形，直径为22mm，高度为0.3mm。所述的隔膜3上圆周阵列有4个直径为1.5mm的圆柱通孔，圆柱通孔中心与所述隔膜3中心的距离为9.5mm。As a preferred example, the diaphragm 3 is cylindrical, with a diameter of 22 mm and a height of 0.3 mm. The diaphragm 3 has four cylindrical through holes with a diameter of 1.5 mm in a circumferential array, and the distance between the center of the cylindrical through hole and the center of the diaphragm 3 is 9.5 mm.
作为一种优选的示例，所述的刚性副骨架2一端应为球面，以拟合人类指尖前端皮肤的外形，所述刚性副骨架2球面的圆孔直径为5mm，在另一端有4个直径为5mm的圆柱，用于插入所述刚性主骨架4并将隔膜3牢牢固定在刚性主骨架4与刚性副骨架2之间。As a preferred example, one end of the rigid sub-skeleton 2 should be spherical to fit the shape of the skin at the front end of the human fingertips. The diameter of the circular hole on the spherical surface of the rigid sub-skeleton 2 is 5 mm, and there are 4 cylinders with a diameter of 5 mm at the other end, which are used to insert the rigid main skeleton 4 and firmly fix the diaphragm 3 between the rigid main skeleton 4 and the rigid sub-skeleton 2.
作为一种优选的示例，所述的毛细钢管5外径为2mm，壁厚为0.2mm，高度为16mm，FBG5放置于所述毛细钢管5的空心正中心位置，引出光纤9的两端用硅橡胶密封。As a preferred example, the outer diameter of the capillary steel tube 5 is 2 mm, the wall thickness is 0.2 mm, and the height is 16 mm. The FBG5 is placed in the hollow center of the capillary steel tube 5, and both ends of the optical fiber 9 are sealed with silicone rubber.
作为一种优选的示例，所述连接件第一端面有4个M2的螺纹通孔，所述螺栓为304不锈钢材质的圆柱头内六角螺栓，所述螺栓的尺寸为M2×8，螺栓旋入所述连接件的螺纹通孔和所述刚性主骨架4第二端面的螺纹孔，以连接并固定所述连接件和所述刚性主骨架4。所述连接件的第二端面有一个圆柱凸起，圆柱上的外螺纹使其可以轻松集成安装到水下执行器的末端。As a preferred example, the first end face of the connector has four M2 threaded through holes, the bolt is a cylindrical hexagon socket bolt made of 304 stainless steel, the size of the bolt is M2×8, and the bolt is screwed into the threaded through hole of the connector and the threaded hole of the second end face of the rigid main frame 4 to connect and fix the connector and the rigid main frame 4. The second end face of the connector has a cylindrical protrusion, and the external thread on the cylinder allows it to be easily integrated and installed at the end of the underwater actuator.
作为一种优选的示例，所述光纤9的纤芯直径为0.15mm，在光纤9上刻有5个FBG，从所述光纤9的一端出发，依次为FBG1，FBG2，FBG3，FBG4，FBG5，刻写方式为飞秒激光逐点刻写。所述FBG1的中心与所述光纤9端头之间的距离为20mm，所述FBG1的中心与所述FBG2的中心距离为28mm，所述FBG2的中心与所述FBG3的中心距离为16mm，所述FBG3的中心与所述FBG4的中心距离为6mm，所述FBG4的中心与所述FBG5的中心距离为40.7mm。所述的每个布拉格光栅的光栅区域为2mm。As a preferred example, the core diameter of the optical fiber 9 is 0.15 mm, and 5 FBGs are engraved on the optical fiber 9, starting from one end of the optical fiber 9, in order of FBG1, FBG2, FBG3, FBG4, and FBG5, and the engraving method is femtosecond laser point-by-point writing. The distance between the center of the FBG1 and the end of the optical fiber 9 is 20 mm, the distance between the center of the FBG1 and the center of the FBG2 is 28 mm, the distance between the center of the FBG2 and the center of the FBG3 is 16 mm, the distance between the center of the FBG3 and the center of the FBG4 is 6 mm, and the distance between the center of the FBG4 and the center of the FBG5 is 40.7 mm. The grating area of each Bragg grating is 2 mm.
作为一种优选的示例，所述柔性指套1的接触区相对于非接触区有一块凸起，可以更好地传导接触力、并将接触力限制在凸起区域内，避免接触力对滑移传感区域产生影响。As a preferred example, the contact area of the flexible finger sleeve 1 has a protrusion relative to the non-contact area, which can better conduct the contact force and limit the contact force within the protrusion area to avoid the contact force affecting the slip sensing area.
在所述指尖传感器与与物体接触并滑动的过程中，基于粘滑现象，摩擦力会使所述指尖的柔性指套1接触区产生形变，该形变通过弹性材料进一步传导到所述柔性指套1的滑移区，引起位于所述柔性指套1滑移区的所述FBG1的轴向应变，得到所述FBG1的光信号波长漂移。In the process of the fingertip sensor contacting and sliding with the object, based on the stick-slip phenomenon, the friction force will cause the contact area of the flexible fingertip 1 of the fingertip to deform, and the deformation is further transmitted to the slip area of the flexible fingertip 1 through the elastic material, causing axial strain of the FBG1 located in the slip area of the flexible fingertip 1, resulting in the wavelength drift of the optical signal of the FBG1.
在所述指尖传感器与物体接触并按压的过程中，正压力会使所述指尖的柔性指套1接触区产生形变，引起位于所述柔性指套1接触区的所述FBG2的应变，得到所述FBG2的光信号波长漂移。When the fingertip sensor contacts and presses an object, the positive pressure will cause the contact area of the flexible fingertip 1 of the fingertip to deform, causing strain of the FBG2 located in the contact area of the flexible fingertip 1, resulting in wavelength drift of the optical signal of the FBG2.
在所述指尖传感器置于水下环境时，静水压和气压在所述隔膜3的两侧形成压力差，压力差会使所述隔膜3产生形变，引起位于所述隔膜3第一端面的所述FBG3和所述FBG4的应变，得到所述FBG3和所述FBG4的光信号波长漂移。When the fingertip sensor is placed in an underwater environment, the hydrostatic pressure and the air pressure form a pressure difference on both sides of the diaphragm 3. The pressure difference causes the diaphragm 3 to deform, causing strain of the FBG3 and the FBG4 located on the first end face of the diaphragm 3, resulting in wavelength drift of the optical signals of the FBG3 and the FBG4.
所述FBG5封装在所述指尖传感器的毛细钢管5里，以隔绝力对所述FBG5信号的影响。温度的变化会引起光纤9光栅栅距的变化，得到所述FBG5的光信号波长漂移。The FBG5 is encapsulated in the capillary steel tube 5 of the fingertip sensor to isolate the influence of force on the signal of the FBG5. The change of temperature will cause the change of the grating pitch of the optical fiber 9, resulting in the wavelength drift of the optical signal of the FBG5.
图1展示了本发明一个较佳的实施例的结构示意图，如图1所示，发明一种光纤光栅仿生指尖传感器包括柔性指套1、刚性副骨架2、隔膜3、刚性主骨架4、毛细钢管5、软填充物6、连接件7、螺栓8、光纤9。Figure 1 shows a schematic structural diagram of a preferred embodiment of the present invention. As shown in Figure 1, a fiber Bragg grating bionic fingertip sensor includes a flexible finger sleeve 1, a rigid sub-skeleton 2, a diaphragm 3, a rigid main skeleton 4, a capillary steel tube 5, a soft filler 6, a connector 7, a bolt 8, and an optical fiber 9.
柔性指套1的材料为Ecoflex 00-30，在制备时需要分两次浇筑。首先是浇筑一个长条形软块，用于将光纤9固定。在光纤9按图1的效果铺放在条形软快并固定后，再浇筑柔性指套1的整体外形。The material of the flexible finger sleeve 1 is Ecoflex 00-30, which needs to be cast in two steps during preparation. First, a long strip of soft block is cast to fix the optical fiber 9. After the optical fiber 9 is laid on the strip of soft block and fixed according to the effect of Figure 1, the overall shape of the flexible finger sleeve 1 is cast.
刚性副骨架2、隔膜3、刚性主骨架4的材料为304不锈钢，将隔膜的4个圆形通孔31对准刚性主骨架的4个空心圆孔41，然后将刚性副骨架的4个圆柱体22对准空心圆柱并按入空心圆柱，使刚性主骨架、隔膜、刚性副骨架紧紧贴合。The materials of the rigid sub-frame 2, diaphragm 3 and rigid main frame 4 are 304 stainless steel. Align the four circular through holes 31 of the diaphragm with the four hollow circular holes 41 of the rigid main frame, then align the four cylinders 22 of the rigid sub-frame with the hollow cylinder and press them into the hollow cylinder to make the rigid main frame, diaphragm and rigid sub-frame fit tightly.
毛细钢管5的材料为304不锈钢，将光纤9穿过毛细钢管5的空腔，并使光纤与毛细钢管同心。然后将毛细钢管5放入刚性主骨架4的另一端空心圆柱61中，并使其同心。然后将软材料Ecoflex 00-30浇筑到空心圆柱的剩余部分，固化后形成软填充物6。据此将光纤9固定在毛细钢管5中，将毛细钢管5固定在刚性主骨架4的空心圆柱中。The material of the capillary steel tube 5 is 304 stainless steel. The optical fiber 9 is passed through the cavity of the capillary steel tube 5, and the optical fiber and the capillary steel tube are made concentric. Then the capillary steel tube 5 is placed in the hollow cylinder 61 at the other end of the rigid main frame 4, and the capillary steel tube 5 is made concentric. Then the soft material Ecoflex 00-30 is poured into the remaining part of the hollow cylinder, and the soft filler 6 is formed after solidification. In this way, the optical fiber 9 is fixed in the capillary steel tube 5, and the capillary steel tube 5 is fixed in the hollow cylinder of the rigid main frame 4.
连接件7的材料为304不锈钢，其中的6个通孔为M2的螺纹通孔71。螺栓8为内六角圆柱头螺钉，根据GB/T 70.1-2008 ，选取螺纹规格为M2×10。通过螺栓8将连接件7与刚性主骨架4固定，将光纤9从连接件7的中心圆柱孔72中穿出。连接件7的圆柱凸起73的外螺纹部分可以安装在机械臂上进行控制。The material of the connector 7 is 304 stainless steel, and the six through holes are M2 threaded through holes 71. The bolt 8 is a hexagon socket head screw, and according to GB/T 70.1-2008, the thread specification is M2×10. The connector 7 is fixed to the rigid main frame 4 by the bolt 8, and the optical fiber 9 is passed through the central cylindrical hole 72 of the connector 7. The external threaded part of the cylindrical protrusion 73 of the connector 7 can be installed on a robot arm for control.
在本实施例中，光纤布拉格光栅波长位移与应变之间的关系可描述为：In this embodiment, the relationship between the fiber Bragg grating wavelength shift and the strain can be described as:
其中，为反射信号的中心波长，为应变光学系数，为应变，为热膨胀系数，为热光系数，为温度的变化量。in, is the central wavelength of the reflected signal, is the strain optical coefficient, For strain, is the coefficient of thermal expansion, is the thermo-optical coefficient, is the change in temperature.
在本实施例中，对于特定的光纤类型应变光学系数是一个常数值，该常数值可以有下述公式得：In this embodiment, for a specific fiber type, the strain optical coefficient is is a constant value, which can be obtained by the following formula:
其中，和表示应变张量的Pockel系数，为泊松比，为光纤的有效折射率。in, and represents the Pockel coefficient of the strain tensor, is Poisson's ratio, is the effective refractive index of the optical fiber.
在测量水压时，由于隔膜3一端为密封空腔，一端受到水压。两端的压力差会使隔膜3产生变形，粘连在隔膜3上的光纤9也会产生变形，使得光纤9上布拉格光栅的栅距发生变化，从而使得反射波长发生变化。测量水压大小的阈值取决于隔膜的厚度，隔膜厚度过薄，水压大小超过阈值时，隔膜会产生塑性形变，导致整体结构的失效。测量水压大小的灵敏度也取决于隔膜的厚度，隔膜厚度过厚，单位水压引起的隔膜形变过小会导致测量的灵敏度不高。通过仿真确定的隔膜的最佳厚度为0.4mm，该厚度隔膜在仿真中耐水压的弹性区间为0-2Mpa。可以较为安全地测量0-100m的水压大小。When measuring water pressure, since one end of the diaphragm 3 is a sealed cavity, one end is subjected to water pressure. The pressure difference at both ends will cause the diaphragm 3 to deform, and the optical fiber 9 adhered to the diaphragm 3 will also deform, causing the grating pitch of the Bragg grating on the optical fiber 9 to change, thereby causing the reflection wavelength to change. The threshold for measuring the water pressure depends on the thickness of the diaphragm. If the diaphragm is too thin, when the water pressure exceeds the threshold, the diaphragm will undergo plastic deformation, resulting in failure of the overall structure. The sensitivity of measuring the water pressure also depends on the thickness of the diaphragm. If the diaphragm is too thick, the deformation of the diaphragm caused by the unit water pressure is too small, resulting in low measurement sensitivity. The optimal thickness of the diaphragm determined by simulation is 0.4mm, and the elastic range of the water pressure resistance of this thickness diaphragm in the simulation is 0-2Mpa. The water pressure of 0-100m can be measured relatively safely.
在水压的作用下，隔膜3会产生径向应变和切向应变，根据小变形理论，隔膜的径向应变和切向应变可以分别表示为下述式子：Under the action of water pressure, the diaphragm 3 will produce radial strain and tangential strain. According to the small deformation theory, the radial strain and tangential strain of the diaphragm can be expressed as follows:
其中，为径向应变，为切向应变，为泊松比，为隔膜受压圆面的半径，为测量点与隔膜圆心的距离，为杨氏模量，为膜的厚度，为水压的大小。对于径向应变，在之间，为负值；在之间，为正值。对于切向应变，从时，均为正值。in, is the radial strain, is the tangential strain, is Poisson's ratio, is the radius of the diaphragm pressure surface, is the distance between the measuring point and the center of the diaphragm, is Young's modulus, is the thickness of the film, is the magnitude of the water pressure. For radial strain , exist between, is a negative value; exist between, is a positive value. , from hour, All are positive values.
在布拉格光栅（FBG）的布置上，将第一个FBG布置在隔膜圆心处，由此，。将第二个FBG布置在处，在该处。由于两个FBG的反射中心波长和非常接近，它们的差值可以忽略不计，可认为。据此经简化后可以得到下述公式：In the arrangement of the Bragg grating (FBG), the first FBG is arranged at the center of the diaphragm circle, so that , . Place the second FBG at at that place Since the reflection center wavelengths of the two FBGs and are very close, their difference can be ignored, and it can be considered . Based on this, the following formula can be obtained after simplification:
通过上述布拉格光栅布置，可以实现。由此通过隔膜中心和边缘的布拉格光栅布置，既对温度进行了补偿，又增大了传感器的灵敏度。By means of the above Bragg grating arrangement, it is possible to achieve The Bragg grating arrangement at the center and edge of the diaphragm not only compensates for the temperature but also increases the sensitivity of the sensor.
具体而言，在本实施例中，，，。代入上述公式可得：Specifically, in this embodiment, , , Substituting into the above formula we get:
配套系统可以有以下基本组件：光源、光纤、FBG询问器(用于信号处理，包括光电探测器和模拟数字转换器)、控制单元。采用激光二极管或超发光二极管产生宽带光信号，在光通过布拉格光栅栅面时，会在布拉格波长产生反射光。当压力或温度使光栅栅距改变时，布拉格波长会发生变化，通过FBG询问器的信号解调输出波长偏移。通过波长偏移量与施加力、温度的标定，可以实现对力、温度等的精确测量。The supporting system can have the following basic components: light source, optical fiber, FBG interrogator (for signal processing, including photodetector and analog-to-digital converter), control unit. Laser diode or superluminescent diode is used to generate broadband optical signal, and when light passes through the Bragg grating surface, reflected light is generated at the Bragg wavelength. When pressure or temperature changes the grating pitch, the Bragg wavelength will change, and the wavelength shift is output through the signal demodulation of the FBG interrogator. By calibrating the wavelength shift with the applied force and temperature, accurate measurement of force, temperature, etc. can be achieved.
与传统传感器相比，本发明实施例的主要优点有：Compared with traditional sensors, the main advantages of the embodiments of the present invention are:
（1）本发明是集成FBG（布拉格光栅）传感原理的多模态仿生指尖传感器，光纤传感具有耐腐蚀，抗电磁干扰，分布式传感，传输损耗低，响应速度快，灵敏度高的特点。对水下智能感知、深海探测、安全人机交互、非结构化环境智能感知与控制等领域有着重要的意义。本发明将FBG集成到软执行器中，可以在非结构化的环境中实现多模态的触觉感知。(1) The present invention is a multi-modal bionic fingertip sensor that integrates the FBG (Bragg grating) sensing principle. Fiber optic sensing has the characteristics of corrosion resistance, anti-electromagnetic interference, distributed sensing, low transmission loss, fast response speed, and high sensitivity. It has important significance in the fields of underwater intelligent perception, deep-sea exploration, safe human-computer interaction, and intelligent perception and control of unstructured environments. The present invention integrates FBG into a soft actuator, which can realize multi-modal tactile perception in an unstructured environment.
（2）本发明利用一种传感原理实现了对接触力、摩擦力、静水压力、温度的多模态智能感知。各个模态的感知测量精度高，信号串扰小，解耦方式简单。(2) The present invention uses a sensing principle to realize multi-modal intelligent perception of contact force, friction force, hydrostatic pressure, and temperature. The perception and measurement accuracy of each mode is high, the signal crosstalk is small, and the decoupling method is simple.
（3）本发明通过结构设计实现了静水压测量时的高灵敏度与温度自补偿。隔膜在过圆心的切面上被设计为两端固定的简支梁形式，在靠近隔膜的边缘和隔膜的中心分别布置了FBG3和FBG4。在静水压作用下，从隔膜的边缘到中心，径向应变由正值逐渐减小到零再变为正值。导致FBG3的波长漂移是温度变化与正径向应变的叠加，FBG4的波长漂移是温度变化与负径向应变的叠加。将FBG3和FBG4的波长漂移相减，既消除了温度对FBG的影响，又放大了静水压力对隔膜产生的波长漂移信号。(3) The present invention achieves high sensitivity and temperature self-compensation in hydrostatic pressure measurement through structural design. The diaphragm is designed as a simply supported beam with both ends fixed on the section through the center of the circle, and FBG3 and FBG4 are arranged near the edge of the diaphragm and the center of the diaphragm respectively. Under the action of hydrostatic pressure, the radial strain gradually decreases from the edge to the center of the diaphragm from a positive value to zero and then to a positive value. The wavelength drift of FBG3 is the superposition of temperature change and positive radial strain, and the wavelength drift of FBG4 is the superposition of temperature change and negative radial strain. Subtracting the wavelength drift of FBG3 and FBG4 not only eliminates the influence of temperature on FBG, but also amplifies the wavelength drift signal generated by hydrostatic pressure on the diaphragm.
（4）本发明通过合理的封装技术避免了其他干扰对温度测量FBG5的影响。通过将FBG5置于毛细钢管空心里，将毛细钢管的剩余空心处填充软材料，再以同样的方式将毛细钢管置于刚性主骨架第一端面空心圆柱里，将空心圆柱剩余部分填充软材料。这种封装技术通过软材料的弹性减小了钢体结构形变对光纤影响，使封装后的FBG5不会因为力的作用产生信号漂移，只会因为温度变化而产生信号漂移。(4) The present invention avoids the influence of other interferences on the temperature measurement FBG5 through reasonable packaging technology. By placing the FBG5 in the hollow of the capillary steel tube, filling the remaining hollow part of the capillary steel tube with soft material, and then placing the capillary steel tube in the hollow cylinder on the first end face of the rigid main skeleton in the same way, and filling the remaining part of the hollow cylinder with soft material. This packaging technology reduces the influence of the deformation of the steel structure on the optical fiber through the elasticity of the soft material, so that the packaged FBG5 will not produce signal drift due to the action of force, but only due to temperature changes.
（5）本发明通过指尖正压力接触区的软材料凸起设计，使得施加的正压力不会对软材料的滑移感知区产生影响。而滑动产生的剪切力又会对滑移感知区产生形变，据此可以将正压力与摩擦力进行解耦。(5) The present invention uses a soft material protrusion design in the fingertip positive pressure contact area so that the applied positive pressure will not affect the slip sensing area of the soft material. The shear force generated by sliding will cause deformation in the slip sensing area, thereby decoupling the positive pressure from the friction force.
以上内容是结合具体/优选的实施方式对本发明所作的进一步详细说明，不能认定本发明的具体实施只局限于这些说明。对于本发明所属技术领域的普通技术人员来说，在不脱离本发明构思的前提下，其还可以对这些已描述的实施方式做出若干替代或变型，而这些替代或变型方式都应当视为属于本发明的保护范围。在本说明书的描述中，参考术语“一种实施例”、“一些实施例”、“优选实施例”、“示例”、“具体示例”、或“一些示例”等的描述意指结合该实施例或示例描述的具体特征、结构、材料或者特点包含于本发明的至少一个实施例或示例中。在本说明书中，对上述术语的示意性表述不必须针对的是相同的实施例或示例。而且，描述的具体特征、结构、材料或者特点可以在任一个或多个实施例或示例中以合适的方式结合。在不相互矛盾的情况下，本领域的技术人员可以将本说明书中描述的不同实施例或示例以及不同实施例或示例的特征进行结合和组合。尽管已经详细描述了本发明的实施例及其优点，但应当理解，在不脱离专利申请的保护范围的情况下，可以在本文中进行各种改变、替换和变更。The above content is a further detailed description of the present invention in combination with specific/preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, it can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description of reference terms "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the absence of mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope of protection of the patent application.
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| CN202411033616.9ACN118565677B (en) | 2024-07-30 | 2024-07-30 | Bionic fingertip sensor based on fiber Bragg grating |
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202411033616.9ACN118565677B (en) | 2024-07-30 | 2024-07-30 | Bionic fingertip sensor based on fiber Bragg grating |
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| CN118565677Atrue CN118565677A (en) | 2024-08-30 |
| CN118565677B CN118565677B (en) | 2025-01-03 |
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202411033616.9AActiveCN118565677B (en) | 2024-07-30 | 2024-07-30 | Bionic fingertip sensor based on fiber Bragg grating |
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| CN (1) | CN118565677B (en) |
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| CN119666040A (en)* | 2024-11-30 | 2025-03-21 | 天津大学 | A tactile sensing device and a method for analyzing the hardness and flatness of an object |
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| US20210293643A1 (en)* | 2018-07-05 | 2021-09-23 | The Regents Of The University Of Colorado, A Body Corporate | Multi-Modal Fingertip Sensor With Proximity, Contact, And Force Localization Capabilities |
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