Dexterous hand force tactile sensor structure, robot dexterous hand and testing method
By combining fiber optic grating sensors with lever arms, the problems of large size and poor durability of traditional sensors are solved, achieving high-precision force and tactile detection and improving the robot's dexterous hand's ability to operate in complex environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANJING FORESTRY UNIV
- Filing Date
- 2026-01-19
- Publication Date
- 2026-05-05
AI Technical Summary
Traditional force and tactile sensors are bulky, have limited response speed, and are not durable enough in the dexterous hands of robots, resulting in low feedback accuracy and failing to meet the needs of fine operation in complex environments.
A fiber optic grating sensor is used, which combines a first and second lever arm that are hinged together with a contact slide rail and an elastic element, along with a limit turntable and a limit stop, to achieve high-precision detection by the fiber optic grating sensor and monitor minute mechanical changes.
It has achieved a sensor with high sensitivity, resistance to electromagnetic interference, corrosion resistance and strong temperature stability, which can operate reliably for a long time in complex environments, simulate the tactile perception of human fingers, and improve the application performance of robots in medical, manufacturing and other fields.
Smart Images
Figure CN121973279A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of tactile perception technology for humanoid robot dexterous hands, specifically to a dexterous hand force tactile sensor structure, a robot dexterous hand, and a testing method. Background Technology
[0002] Fiber Bragg grating (FBG) technology exhibits unique advantages in force and tactile sensors for robotic dexterity hands. As the demand for robots to perform delicate manipulations and force sensing tasks in complex environments continues to grow, traditional force and tactile sensors are increasingly showing their limitations due to their large size, limited response speed, and insufficient durability. In contrast, FBG sensors can sense mechanical forces such as pressure, bending, or tension by monitoring minute changes in the wavelength of reflected light in the optical fiber, thus achieving high-precision real-time detection of external forces. This characteristic enables robots to obtain more accurate force feedback during grasping and manipulation, significantly improving their application capabilities in fields such as medicine, manufacturing, and service. Traditional force and tactile sensors suffer from limitations that lead to low sensor feedback accuracy. Summary of the Invention
[0003] The purpose of this application is to provide a dexterous hand force tactile sensor structure, a robot dexterous hand, and a testing method to solve the above-mentioned defects caused by the prior art.
[0004] To achieve the above objectives, this application employs the following technical solution: Firstly, this application discloses a dexterous hand force tactile sensor structure, which includes... A first lever arm and a second lever arm are hinged to each other, and the hinge point of the first lever arm and the second lever arm is equidistant from the ends of the first lever arm and the second lever arm in the same direction. A contact slide rail is provided with an elastic element inside. The first lever arm and the second lever arm are slidably connected to the contact slide rail and correspondingly connected to the two ends of the elastic element. A fiber optic grating sensor, wherein the fiber optic grating sensor is connected to the other side of the first lever arm and the second lever arm.
[0005] In a further embodiment of this application, a limiting turntable is provided at the hinge joint of the first lever arm and the second lever arm, and a limiting stop bar is provided on both the first lever arm and the second lever arm. The limiting stop bar cooperates with the limiting turntable to limit the movement of each lever arm.
[0006] In a further embodiment, the limiting turntable is coaxially arranged with the hinge point of the first lever arm and the second lever arm.
[0007] In a further embodiment of this application, the ends of the first lever arm and the second lever arm are provided with fiber optic grating guide slots, the two fiber optic grating guide slots are arranged coplanarly, and the fiber optic grating sensor is fixed in the fiber optic grating guide slot.
[0008] In a further embodiment of this application, the first lever arm and the second lever arm have the same structure; The first lever arm includes a fixedly connected rod and a sliding rod. The two ends of the rod are connected to the elastic element and the fiber optic grating sensor respectively. The sliding rod is slidably placed in a groove on the contact slide rail.
[0009] Secondly, this application provides a robotic dexterous hand, which includes the aforementioned dexterous hand force tactile sensor structure.
[0010] In a further embodiment, the dexterous hand force tactile sensor structure is fixed on the robotic finger of the robot's dexterous hand, and the contact slide rail is fixed at the fingertip of the robotic finger.
[0011] Thirdly, this application also discloses a testing method for the robot dexterity hand as described above, which includes the following steps: One end of the fiber optic cable of the fiber optic sensor is electrically connected to the demodulation system, and wavelength zero-point calibration is performed. A unit weight of the object to be tested is placed on the fingertip of the robot's dexterous hand and makes contact with the slide rail; due to gravity, the first lever arm and the second lever arm move in opposite directions, causing the fiber optic grating sensor to be stretched and taut, and the demodulation system detects the drift signal in real time. The object under test remains stationary within a preset time period, and the recorded value is used as the drift value corresponding to that weight. Repeat the test by changing the test object to different weights; By comparing the linearity of the Bragg wavelength drift measured under different weights, the performance of the robot's dexterity hand can be determined.
[0012] In a further embodiment of this application, when the fiber Bragg grating sensor is subjected to a normal external force, according to the geometric relationship and the characteristics of the fiber Bragg grating, the external force and the Bragg wavelength drift satisfy the following relationship; ; Among them, among them, This is the Bragg wavelength shift. The strain sensitivity coefficient, The angle between the power arm and the contact rail in the initial state. The force acting on the resistance arm is the force. For the force acting on a linear elastic element, This is the distance from the linear elastic element to the hinge point; F External force; This is the elastic proportionality coefficient of the elastic element. For the length of the boom, The length of the resistance arm. For fiber strain, This represents the change in fiber length. This is the initial grating length.
[0013] The beneficial effects of this application are as follows: This application utilizes a fiber Bragg grating as the core sensing element, employing two interleaved lever arms in conjunction with a contact rail for synchronous triggering at both ends of the fiber Bragg grating sensor. This solves the problems of large size, poor durability, susceptibility to interference, and low accuracy inherent in traditional electrical sensors used in dexterous hand applications. The sensor boasts advantages such as high sensitivity, resistance to electromagnetic interference, corrosion resistance, and strong temperature stability, enabling long-term reliable operation in complex environments. Furthermore, its lightweight structure allows it to simulate the tactile perception of human fingers, achieving high-precision detection of minute external forces and improving the performance and reliability of robots in fields such as medical surgery, precision manufacturing, and remote operation. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of the structure of the dexterous hand force tactile sensor in the embodiments of this application; Figure 2 This is a schematic diagram of the structure of the rotating power arm in an embodiment of this application; Figure 3 This is a schematic diagram illustrating the geometric relationships and force analysis during the measurement process of the force-tactile sensor in the embodiments of this application; Figure 4 This is a schematic diagram of an embodiment of the force-tactile sensor integrated with a dexterous hand in this application. Figure 5 This is a schematic diagram of the force-touch sensor test performance data in an embodiment of this application; Figure 6 This is a flowchart illustrating the testing method in an embodiment of this application.
[0015] in: 1. Fiber Bragg grating sensor; 2. Limiting turntable; 3. Elastic element; 4. Contact slide rail; 5. First lever arm; 51. Second lever arm; 52. Limiting stop bar; 6. Robotic finger; 7. Object to be measured; 8. Robotic dexterity hand; 9. Demodulation system; 501. Fiber Bragg grating guide groove; 502. Rod body; 503. Fixing hole; 504. Slide bar. Detailed Implementation
[0016] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use.
[0017] like Figure 1As shown, this application discloses an embodiment of a dexterous hand force tactile sensor structure, which includes a first arm 5 and a second arm 51 hinged to each other, a contact slide rail 4, and a fiber Bragg grating sensor 1; the hinge point of the first arm 5 and the second arm 51 is equidistant from the same-direction ends of the first arm 5 and the second arm 51; an elastic element 3 is provided in the contact slide rail 4, and in this embodiment, the elastic element 3 is a spring; one side of the first arm 5 and the second arm 51 is slidably connected to the contact slide rail 4 and correspondingly connected to the two ends of the elastic element 3; the fiber Bragg grating sensor 1 is connected to the other side of the first arm 5 and the second arm 51.
[0018] In use, the contact slide rail 4 is used as the force-bearing surface. When it is compressed, the first lever arm 5 and the second lever arm 51 move in an alternating motion. At this time, the elastic element 3 is compressed, and the fiber optic grating sensor 1 is stretched. The information of the fiber optic grating sensor 1 is fed back to the external processing system for real-time force feedback. After the external force is removed, the first lever arm 5 and the second lever arm 51 can be reset.
[0019] In some embodiments, a dexterous hand force tactile sensor structure is specifically designed as follows; As attached Figure 1 As shown, this embodiment also adds a limiting turntable 2 and a limiting stop bar 52; the limiting stop bar 52 is fixed to the first force arm 5 and the second force arm 51 on both sides of the limiting turntable 2 by bolts, the limiting turntable 2 is fixed at the hinge of the first force arm 5 and the second force arm 51, the limiting turntable 2 is coaxially arranged with the hinge point of the first force arm 5 and the second force arm 51, the ends of the first force arm 5 and the second force arm 51 are provided with fiber optic grating guide grooves 501, the two fiber optic grating guide grooves 501 are arranged coplanarly, the fiber optic grating sensor 1 is fixed in the fiber optic grating guide grooves 501 by adhesive bonding; its sensitive grating section is located in the same plane as the rotation center, wherein when the limiting stop bar 52 on the first force arm 5 and the second force arm 51 contacts the limiting turntable 2, it is the initial state of the structure, the linear elastic element 3 serves as both a scaling factor when the sensor measures and a reset and rebound device after the external force is removed; As attached Figure 2 As shown, in this embodiment, the first lever arm 5 and the second lever arm 51 have the same structure. Taking the first lever arm 5 as an example, the first lever arm 5 includes a rod body 502 and a slide rod 504 that are fixedly connected. The two ends of the rod body 502 are connected to the elastic element 3 and the fiber Bragg grating sensor 1 respectively. The slide rod 504 is slidably placed in the groove on the contact slide rail 4. The rod body 502 is also provided with a fixing hole 503 to facilitate the installation of the spring. In this embodiment, the contact slide rail 4 is a closed structure with two layers. The two lever arms are limited in one end in the same direction in the slide rail. When the outside of the slide rail is subjected to a normal external force, the external force is converted into a lateral force acting on the two lever arms. The two lever arms rotate around the limiting rotating disk, causing the fiber Bragg grating sensor 1 to undergo strain, causing Bragg wavelength drift. The magnitude of the external force can be obtained through the demodulation system 9.
[0020] The fiber grating sensor 1 adopts a single-mode fiber structure and can be coated with different layers according to sensitivity requirements, including bare fiber, polyimide, acrylate or metal coating, and the core material includes quartz fiber, borosilicate glass fiber and polymer fiber.
[0021] As an improvement of this application, the materials of the first lever arm 5 and the second lever arm 51 can be aluminum alloy, titanium alloy or resin, and the surface roughness of the slide bar 504 is less than 3.2 μm to reduce frictional resistance.
[0022] Reference Appendix Figure 4 This application provides another embodiment, which relates to a robot dexterous hand 8, which includes the dexterous hand force tactile sensor structure in the above embodiment, wherein the dexterous hand force tactile sensor structure is fixed on the robot finger 6 of the robot dexterous hand 8, and the contact slide rail 4 is fixed at the fingertip position of the robot finger 6.
[0023] like Figure 6 As shown, based on the above-mentioned robot dexterity hand 8, this application also discloses a testing method for the robot dexterity hand 8, which includes the following steps; One end of the fiber optic cable of the fiber optic sensor 1 is electrically connected to the demodulation system 9, and wavelength zero-point calibration is performed. The test object 7 of unit weight is placed on the fingertip of the robotic finger 6 of the robot's dexterous hand 8 and contacts the contact rail 4; due to gravity, the first lever arm 5 and the second lever arm 51 move in opposite directions, causing the fiber optic grating sensor 1 to be stretched and taut, and the demodulation system 9 detects the drift signal in real time. The test object 7 stays for a preset time period and is recorded as the drift value corresponding to that weight; Repeat the test by replacing the test object 7 with different weights; By comparing the linearity of the Bragg wavelength drift measured under different weights, the performance of the robot's dexterity hand 8 can be judged. The degree of linearity is directly proportional to the performance of the robot's dexterity hand 8.
[0024] In some embodiments, the specific process of the test method is as follows; During installation, the sensor is fixed to the fingertip of the robotic finger 6 of the robot's dexterous hand 8, ensuring that the sensor contact rail 4 faces outwards for easy force transmission. One end of the fiber optic cable of the fiber optic sensor 1 is connected to the demodulation system 9, which is then powered on and performs wavelength zero-point calibration. During the loading phase, a 5 g standard weight is gently placed on the contact surface directly opposite the finger. The weight's gravity acts on the first lever arm 5 and the second lever arm 51 via the contact slide rail 4. The first lever arm 5 and the second lever arm 51 rotate slightly around the limiting rotating disk, causing the fiber optic grating sensor 1 to generate tensile strain. The demodulation system 9 records the Bragg wavelength drift curve over time in real time. During the holding phase, the weight is kept stationary on the machine finger 6 for approximately 10 seconds until the wavelength drift curve output by the demodulation system 9 stabilizes. The stable value is recorded as the drift value corresponding to that weight.
[0025] The weights were gently removed, and the elastic element 3 restored the two lever arms to their initial positions. The wavelength signal of the fiber optic grating sensor 1 returned to near zero, verifying the reset performance.
[0026] Repeat the experiment, changing the weights to 20 g and 50 g in turn, and perform loading, holding and unloading operations according to the above steps, recording three sets of wavelength drift stability values respectively.
[0027] As attached Figure 3 As shown, when a fiber Bragg grating sensor is subjected to a normal external force, according to geometric relationships and the characteristics of the fiber Bragg grating, the external force and Bragg wavelength drift satisfy the following relationship; ; in, This is the Bragg wavelength shift. The strain sensitivity coefficient, The angle between the power arm and the contact rail in the initial state. The force acting on the resistance arm is the force. For the force acting on a linear elastic element, This is the distance from the linear elastic element to the hinge point; F External force; This is the elastic proportionality coefficient of the elastic element. For the length of the boom, The length of the resistance arm. For fiber strain, This represents the change in fiber length. This is the initial grating length.
[0028] As attached Figure 5 As shown, the force-tactile sensor can generate detectable Bragg wavelength shift under a small external force of 5 g. The wavelength shift at 20 g and 50 g shows a good linear relationship with the external force, with a fitting correlation coefficient R² greater than 0.95. The experiment also verifies that the sensor has small hysteresis error and excellent reset performance, indicating that the sensor can achieve high-sensitivity detection of small forces and is suitable for tactile sensing applications in robotic dexterity hands.
[0029] It's worth mentioning that fiber Bragg grating sensors possess several advantages: strong resistance to electromagnetic interference, high temperature stability, good corrosion resistance, and excellent sensitivity. Even in high-temperature, humid, or complex electromagnetic environments, fiber Bragg grating sensors can maintain stable operation for extended periods and accurately capture subtle changes in external forces, thus providing robots with more natural and continuous tactile feedback. This not only allows them to more closely resemble the tactile perception of human fingers but also overcomes the limitations of traditional sensors in terms of accuracy and dexterity, making them an ideal choice for building high-performance robotic force-tactile systems.
[0030] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.
[0031] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.
Claims
1. A dexterous hand force tactile sensor structure, characterized in that, include A first lever arm and a second lever arm are hinged to each other, and the hinge point of the first lever arm and the second lever arm is equidistant from the ends of the first lever arm and the second lever arm in the same direction. A contact slide rail is provided with an elastic element inside. The first lever arm and the second lever arm are slidably connected to the contact slide rail and correspondingly connected to the two ends of the elastic element. A fiber optic grating sensor, wherein the fiber optic grating sensor is connected to the other side of the first lever arm and the second lever arm.
2. The dexterous hand force tactile sensor structure according to claim 1, characterized in that, A limiting turntable is provided at the hinge of the first lever arm and the second lever arm, and a limiting stop bar is provided on both the first lever arm and the second lever arm. The limiting stop bar works with the limiting turntable to limit the movement of each lever arm.
3. The dexterous hand force tactile sensor structure according to claim 2, characterized in that, The limiting turntable is coaxially arranged with the hinge point of the first lever arm and the second lever arm.
4. The dexterous hand force tactile sensor structure according to claim 1, characterized in that, The ends of the first lever arm and the second lever arm are provided with fiber optic grating guide slots, the two fiber optic grating guide slots are arranged coplanarly, and the fiber optic grating sensor is fixed in the fiber optic grating guide slot.
5. The dexterous hand force tactile sensor structure according to claim 1, characterized in that, The first lever arm and the second lever arm have the same structure; The first lever arm includes a fixedly connected rod and a sliding rod. The two ends of the rod are connected to the elastic element and the fiber optic grating sensor respectively. The sliding rod is slidably placed in a groove on the contact slide rail.
6. A robotic dexterous hand, characterized in that, Includes the dexterous hand force tactile sensor structure as described in any one of claims 1 to 5.
7. The robotic dexterous hand according to claim 6, characterized in that, The dexterous hand force tactile sensor structure is fixed on the robotic finger of the robot's dexterous hand, and the contact slide rail is fixed at the fingertip of the robotic finger.
8. A testing method for a robot dexterous hand as described in any one of claims 6 to 7, characterized in that, include One end of the fiber optic cable of the fiber optic sensor is electrically connected to the demodulation system, and wavelength zero-point calibration is performed. A unit weight of the object to be tested is placed on the fingertip of the robot's dexterous hand and makes contact with the slide rail; due to gravity, the first lever arm and the second lever arm move in opposite directions, causing the fiber optic grating sensor to be taut and pulled up, and the demodulation system detects the drift signal in real time. The object under test remains stationary within a preset time period, and the recorded value is used as the drift value corresponding to that weight. Repeat the test by changing the test object to different weights; By comparing the linearity of the Bragg wavelength drift measured under different weights, the performance of the robot's dexterity hand can be determined.
9. The test method according to claim 8, characterized in that, When the fiber Bragg grating sensor is subjected to a normal external force, according to geometric relationships and fiber Bragg grating characteristics, the external force and Bragg wavelength drift satisfy the following relationship: ； in, This is the Bragg wavelength shift. The strain sensitivity coefficient, The angle between the power arm and the contact rail in the initial state. The force acting on the resistance arm is the force. For the force acting on a linear elastic element, This is the distance from the linear elastic element to the hinge point; F External force; This is the elastic proportionality coefficient of the elastic element. For the length of the boom, The length of the resistance arm. For fiber strain, This represents the change in fiber length. This is the initial grating length.