Fingertip force sensing device and dexterous hand

Abstract

The utility model discloses a fingertip force perception device and deft hand, fingertip force perception device includes finger base body, stress part, elastic connecting piece, first detection element and second detection element, and stress part sets up in the end of finger base body, and elastic connecting piece is connected between finger base body and stress part, and elastic connecting piece is configured as when the stress part is subjected to external force, and elastic deformation is generated, first detection element sets up in finger base body, and second detection element sets up in stress part, first detection element and second detection element are configured as through the position or physical quantity change of second detection element relative to first detection element caused by the deformation of elastic connecting piece is detected, to perceive the size and / or direction of external force. The utility model makes the deft hand fingertip more compact and greater detection range completely, and, guarantees the consistency, accuracy and reliability of measurement result from factory calibration to actual use process.

Description

Technical Field

[0001] This utility model relates to the field of robotics technology, and in particular to a fingertip force sensing device and a dexterous hand. Background Technology

[0002] With the rapid development of embodied intelligence and humanoid robot technology, dexterous hands need to perform fine operations in complex, unstructured environments, which places extremely high demands on their real-time and accurate fingertip force sensing capabilities. Currently, the technological approaches to achieving fingertip force sensing in the industry are mainly divided into two categories: The first type is the indirect measurement method based on joint current estimation. This method infers the force on the fingertip by measuring the motor current that drives the fingertip movement. Its drawback is that due to nonlinear factors such as gear backlash, friction, and damping in the transmission chain, the force sensing accuracy is poor and the response is sluggish, which cannot meet the requirements of high-precision grasping and interaction.

[0003] The second type involves installing independent force sensors on the fingertips. While this method offers higher accuracy than the former, it introduces new technical bottlenecks: First, external force sensors significantly increase the size of the fingertip, contradicting the trend towards miniaturization and integration in dexterous hands, thus limiting its application in compact spaces. Second, while sensors require factory calibration, installation stress and deformation of connectors introduce new systematic errors after installation, leading to inaccurate measurements. Third, existing fingertip force sensors typically only sense the resultant force and torque, failing to identify the specific point of application of the force, thus limiting the dexterous hand's precise judgment of contact states. Furthermore, some tactile sensing solutions based on 6D Hall arrays suffer from poor electromagnetic compatibility and limited force detection range.

[0004] Therefore, there is an urgent need in this field for a solution that can achieve a larger detection range and higher detection accuracy while meeting the requirements of miniaturization. Utility Model Content

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a fingertip force sensing device and a dexterous hand, aiming to improve the detection range and accuracy under the premise of miniaturization.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: On the one hand, this utility model provides a fingertip force sensing device, comprising: Finger matrix; The force-bearing part is located at the end of the finger base; An elastic connector is provided between the finger base and the force-receiving part, and the elastic connector is configured to produce elastic deformation when the force-receiving part is subjected to an external force. A first detection element is disposed on the finger base; A second detection element is disposed at the force-bearing part; The first detection element and the second detection element are configured to sense the magnitude and / or direction of an external force by detecting changes in the position or physical quantity of the second detection element relative to the first detection element caused by the deformation of the elastic connector.

[0007] Furthermore, the elastic connector includes a base and elastic arms respectively disposed on both sides of the base. Each elastic arm has a first mounting hole at one end away from the base that connects to the finger base, and the base has a second mounting hole that connects to the force-bearing part.

[0008] Furthermore, the elastic arm includes a vertical section and a horizontal connecting section. One end of the vertical section is connected to the base, and the other end of the vertical section is connected to the horizontal connecting section. The horizontal connecting section is provided with the first mounting hole.

[0009] Furthermore, the vertical segment includes two bends arranged at relative intervals, and the horizontal connecting segment is connected to the two bends.

[0010] Furthermore, the spacing between the elastic arms on both sides of the base is greater than the width of the first detection element.

[0011] Furthermore, the second mounting hole is located at the center of the base.

[0012] Furthermore, the horizontal connecting segment is semi-circular in shape.

[0013] Furthermore, the force-receiving part includes a plurality of independent force-receiving sub-parts arranged along its length direction. Each force-receiving sub-part is connected to the finger base through a corresponding elastic connector and is equipped with a corresponding first detection element and second detection element.

[0014] Furthermore, it also includes a wrapping layer that covers the outside of the finger base and the force-bearing part.

[0015] On the other hand, this utility model also provides a dexterous hand, including the aforementioned fingertip force sensing device.

[0016] The advantages of this invention compared to existing technologies are as follows: A fingertip force sensing device includes a finger base, a force-receiving part, an elastic connector, a first detection element, and a second detection element. The force-receiving part is located at the end of the finger base, and the elastic connector connects the finger base and the force-receiving part. The elastic connector is configured to undergo elastic deformation when the force-receiving part is subjected to an external force. The first detection element is located on the finger base, and the second detection element is located on the force-receiving part. The first and second detection elements are configured to sense the magnitude and / or direction of the external force by detecting the change in position or physical quantity of the second detection element relative to the first detection element caused by the deformation of the elastic connector. By integrating the key force sensing components into the internal structure of the finger, the volume redundancy problem caused by judging the force value of the fingertip based on the magnitude of the current is completely avoided. This makes the fingertip more compact and provides a larger detection range. At the same time, this integrated design minimizes the force transmission path, avoids installation errors and stress interference introduced by additional installation interfaces, and ensures the consistency, accuracy, and reliability of measurement results from factory calibration to actual use.

[0017] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model, it can be implemented according to the contents of the specification. In order to make the above and other objectives, features and advantages of this utility model more obvious and easy to understand, the following are preferred embodiments, which are described in detail below. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of the external shape of a fingertip force sensing device provided for a specific embodiment of this utility model; Figure 2 An exploded view of a fingertip force sensing device provided in a specific embodiment of this utility model; Figure 3 A schematic diagram of the structure of the elastic connector provided in a specific embodiment of this utility model; Figure 4 A schematic diagram of the structure of the finger substrate provided in a specific embodiment of this utility model.

[0020] Figure Labels 1. Finger base; 11. Cavity; 2. Force-bearing part; 21. Force-bearing sub-part; 3. Elastic connector; 31. Base; 311. Second mounting hole; 32. Elastic arm; 321. Vertical section; 3211. Bending part; 322. Horizontal connecting section; 3221. First mounting hole; 4. First detection element; 5. Second detection element; 6. Wrapping layer. Detailed Implementation

[0021] The technical solution of this utility model will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0022] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to 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 of this utility model.

[0023] Furthermore, the terms "first" and "second" 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, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0024] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0025] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0026] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0027] like Figures 1 to 4 As shown, this utility model embodiment provides a fingertip force sensing device, including a finger base 1, a force receiving part 2, an elastic connector 3, a first detection element 4, and a second detection element 5. The force receiving part 2 is disposed at the end of the finger base 1, and the elastic connector 3 is connected between the finger base 1 and the force receiving part 2. The elastic connector 3 is configured to generate elastic deformation when the force receiving part 2 is subjected to an external force. The first detection element 4 is disposed on the finger base 1, and the second detection element 5 is disposed on the force receiving part 2. The first detection element 4 and the second detection element 5 are configured to sense the magnitude and / or direction of the external force by detecting the change in position or physical quantity of the second detection element 5 relative to the first detection element 4 caused by the deformation of the elastic connector 3.

[0028] Specifically, the finger base 1, serving as the support structure of the device, is typically made of rigid materials such as metal or high-strength engineering plastics. Its interior can accommodate circuitry and wiring, and its shape resembles a human finger. The force-bearing part 2 is located at the end of the finger base 1, and its outer surface is designed as a force-bearing surface for contact with external objects.

[0029] The elastic connector 3 can be made of materials with good elastic deformation capacity and fatigue life, such as spring steel, beryllium bronze, or high-performance engineering plastics. The elastic connector 3 can be a spring, an elastic block, or a flexible hinge structure that is easily deformable through hollow or slotted design.

[0030] The first detection element 4 and the second detection element 5 together constitute a displacement or physical quantity detection system. The first detection element 4 and the second detection element 5 can be a combination of a Hall sensor and a magnet, or other devices capable of detecting minute displacements or changes in relative position, such as a combination of an optical displacement sensor and a reflective marker, the two plates of a capacitive sensor, or a strain gauge, etc.

[0031] Taking the combination of a Hall sensor and a magnet as an example, the first detection element 4 is a Hall sensor, fixedly mounted on the finger base 1 and precisely aligned with the deformation area of ​​the elastic connector 3. Correspondingly, the second detection element 5 is a permanent magnet, fixedly mounted on the force-receiving part 2 and moving together with it. When an external force causes the elastic connector 3 to deform, it will cause a slight displacement or angular deflection of the force-receiving part 2 relative to the finger base 1. This relative movement directly changes the relative position between the permanent magnet and the Hall sensor, resulting in a linear change in the magnetic field strength detected by the Hall sensor. This changing electrical signal is acquired, amplified, and converted by the subsequent signal processing circuit, and finally the magnitude and direction of the external force are calculated through a pre-calibrated signal-force mapping relationship.

[0032] By integrating the key force-sensing components into the finger's internal structure, the volume redundancy problem caused by using current magnitude to determine the force applied to the fingertip is completely avoided. This makes the fingertip more compact and allows for a larger detection range. At the same time, this integrated design minimizes the force transmission path, avoiding installation errors and stress interference introduced by additional mounting interfaces, and ensuring the consistency, accuracy, and reliability of measurement results from factory calibration to actual use.

[0033] exist Figure 3 In the embodiment shown, the elastic connector 3 includes a base 31 and elastic arms 32 respectively disposed on both sides of the base 31. Each elastic arm 32 has a first mounting hole 3221 for connecting to the finger base 1 at one end away from the base 31, and the base 31 has a second mounting hole 311 for connecting to the force-bearing part 2.

[0034] Specifically, the base 31 is a plate-like structure with sufficient rigidity, and its central region has a second mounting hole 311, which is preferably a threaded hole or a smooth hole, for reliably connecting with the force-bearing part 2 by fasteners such as screws. Two elastic arms 32 extend integrally from both sides of the base 31, forming a roughly symmetrical cantilever beam structure. Each elastic arm 32 has a first mounting hole 3221 at its end away from the base 31, which is also fixedly connected to the finger base 1 by fasteners such as screws. This fixed connection at both ends allows the elastic connector 3 to provide the necessary connection support between the force-bearing part 2 and the finger base 1, and also allows the force-bearing part 2 to produce small movements with multiple degrees of freedom relative to the finger base 1 through the bending deformation of the elastic arms 32.

[0035] Specifically, when an external force is applied to the force-bearing part 2, the force is transmitted through the base 31 and distributed to the two elastic arms 32. Since the base 31 itself has high stiffness, the main deformation occurs in the relatively weaker elastic arms 32. The cross-sectional shape, length, and width of the elastic arms 32 can be precisely designed according to the required force sensing range and sensitivity. For example, to obtain a larger deformation displacement to improve detection sensitivity, the elastic arms 32 can be designed as a slender structure with a large aspect ratio; while to withstand a larger load and increase the range, the cross-sectional thickness of the elastic arms 32 can be increased or its effective length reduced.

[0036] The symmetrical double-arm design makes the movement of the force-bearing part 2 more stable, avoiding the swaying or instability that may be caused by single-point support, thereby improving the accuracy and repeatability of force detection. Secondly, by concentrating the main deformation in a specific elastic arm 32 area, the first detection element 4 and the second detection element 5 can more accurately detect the relative displacement changes caused by force.

[0037] exist Figure 3 In the embodiment shown, the elastic arm 32 includes a vertical section 321 and a horizontal connecting section 322. One end of the vertical section 321 is connected to the base 31, and the other end of the vertical section 321 is connected to the horizontal connecting section 322. The horizontal connecting section 322 is provided with a first mounting hole 3221.

[0038] Specifically, one end of the vertical segment 321 is fixedly connected to the base 31 of the elastic connector 3, while the other end is connected to the horizontal connecting segment 322. The vertical segment 321 serves as the main elastic deformation area, and the horizontal connecting segment 322 is located at the end of the vertical segment 321, preferably designed as a plate-like structure with high rigidity. The main function of the horizontal connecting segment 322 is to provide a stable and reliable mounting interface for the connection between the elastic arm 32 and the finger base 1. This design effectively separates the elastic deformation function from the mounting and fixing function, allowing the vertical segment 321 to focus on generating bending deformation, while the horizontal connecting segment 322 ensures a rigid connection with the finger base 1, avoiding interference with measurement accuracy due to localized deformation at the mounting interface. Furthermore, the plate-like structure of the horizontal connecting segment 322 provides a larger mounting contact area, allowing for a more uniform distribution of the fastener's preload, which not only enhances connection reliability but also effectively reduces stress concentration and improves the fatigue life of the elastic arm 32.

[0039] exist Figure 3 In the illustrated embodiment, the vertical segment 321 includes two bends 3211 arranged at intervals, and the horizontal connecting segment 322 is connected to the two bends 3211. Each bend 3211 can be designed as an elastic beam with at least one bending point. This design effectively resists lateral forces and torques in non-working directions, greatly improving the anti-interference capability and measurement stability under complex stress conditions.

[0040] In some embodiments, the spacing between the elastic arms 32 on both sides of the base 31 is greater than the width of the first detection element 4. This design avoids mechanical interference and ensures that the elastic arms 32 can freely and smoothly undergo elastic deformation within their designed stroke, thereby ensuring the accuracy of the linear relationship between force and deformation, preventing sensor damage or measurement inaccuracies caused by structural collisions, and making the structure more compact and reducing space occupation.

[0041] exist Figure 4 In the embodiment shown, the finger base 1 has a cavity 11 for accommodating the first detection element 4. During installation, the first detection element 4 can be placed in the cavity 11, which can further reduce the space occupied.

[0042] exist Figure 3 In the embodiment shown, the horizontal connecting segment 322 is semi-circular in shape. This design reduces space occupation compared to a circular shape, which is beneficial for spatial layout.

[0043] In some embodiments, the force-receiving part 2 is configured to include a plurality of independent force-receiving sub-parts 21 arranged along its length. These force-receiving sub-parts 21 are physically separated from each other, preferably mechanically decoupled by providing physical gaps between their adjacent sides. Each force-receiving sub-part 21 is connected to the finger base 1 via a corresponding, independent elastic connector 3. Simultaneously, for each independent mechanical unit composed of the force-receiving sub-part 21 and the elastic connector 3, an independent detection system is provided, which includes a first detection element 4 disposed on the finger base 1 and a second detection element 5 disposed on the corresponding force-receiving sub-part 21.

[0044] For example, in an embodiment where the force-receiving part 2 is divided into three independent force-receiving sub-parts 21, these three sub-parts can be arranged sequentially along the axial direction of the fingertip. Each force-receiving sub-part 21 can be designed as a rectangular block of similar size, separated from each other by a gap of one to two millimeters. Each force-receiving sub-part 21 is mounted on a common finger base 1 via its own elastic connector 3, whose structural parameters may be the same or different. Accordingly, each elastic connector 3 has an independent set of detection elements within its corresponding space.

[0045] When an external object comes into contact with the fingertip, the force typically acts on only one or a few of the force-bearing sub-parts 21. By reading and comparing the signal outputs of these three independent sensing channels, the control system can accurately determine which sub-part(s) are subjected to force and the magnitude difference of the force on each sub-part. Combining the known physical coordinates of each sub-part, the algorithm can calculate the specific area of ​​action or contact point of the external force on the fingertip surface. This surpasses the limitation of traditional single-point force sensors, which can only measure the resultant force but cannot locate the point. Secondly, this structure significantly improves the spatial resolution of perception and the ability to acquire multi-dimensional information. It can not only sense normal force, but also infer the existence of shear force or torque by analyzing the differences in lateral force on different sub-parts, providing rich tactile information for dexterous hands to achieve more precise object manipulation.

[0046] In some embodiments, the fingertip force sensing device further includes a wrapping layer 6, which serves as an external encapsulation structure and continuously and completely covers the outside of the finger base 1 and the force-receiving part 2.

[0047] The encapsulation layer 6 is preferably made of a polymer material with elasticity and flexibility, such as silicone rubber, thermoplastic polyurethane or natural rubber, and is combined with the internal structure by means of compression molding, impregnation molding or sleeve installation.

[0048] The encapsulation layer 6 provides a sealed protection, effectively preventing external contaminants such as dust, moisture, and oil from entering the device. It protects the delicate elastic connector 3 and detection elements from corrosion, contamination, or physical damage, significantly improving the device's reliability and service life in harsh industrial environments. Furthermore, as a force transmission medium, the encapsulation layer 6 disperses and evenly transmits concentrated force to the internal force-receiving parts 2 or individual force-receiving sub-parts 21 when an external object comes into contact with the fingertip. This avoids localized stress concentration and makes the force application smoother, improving the stability and accuracy of the measurement.

[0049] This embodiment of the invention also provides a dexterous hand, including the aforementioned fingertip force sensing device. Apart from the fingertip force sensing device, the remaining structures of the dexterous hand are identical to those in the prior art, and will not be described in detail here.

[0050] It should be noted that the dexterous hand provided in this embodiment of the present invention includes the above-mentioned fingertip force sensing device, and therefore the dexterous hand has all the beneficial effects of the above-mentioned fingertip force sensing device, which will not be repeated here.

[0051] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A fingertip force sensing device, characterized in that, include: Finger matrix; The force-bearing part is located at the end of the finger base; An elastic connector is provided between the finger base and the force-receiving part, and the elastic connector is configured to produce elastic deformation when the force-receiving part is subjected to an external force. A first detection element is disposed on the finger base; A second detection element is disposed at the force-bearing part; The first detection element and the second detection element are configured to sense the magnitude and / or direction of an external force by detecting changes in the position or physical quantity of the second detection element relative to the first detection element caused by the deformation of the elastic connector.

2. The fingertip force sensing device according to claim 1, characterized in that, The elastic connector includes a base and elastic arms respectively disposed on both sides of the base. Each elastic arm has a first mounting hole at the end away from the base that is connected to the finger base, and the base has a second mounting hole that is connected to the force-bearing part.

3. The fingertip force sensing device according to claim 2, characterized in that, The elastic arm includes a vertical section and a horizontal connecting section. One end of the vertical section is connected to the base, and the other end of the vertical section is connected to the horizontal connecting section. The horizontal connecting section is provided with the first mounting hole.

4. A fingertip force sensing device according to claim 3, characterized in that, The vertical section includes two bends arranged at relative intervals, and the horizontal connecting section is connected to the two bends.

5. A fingertip force sensing device according to claim 2, characterized in that, The distance between the elastic arms on both sides of the base is greater than the width of the first detection element.

6. A fingertip force sensing device according to claim 2, characterized in that, The second mounting hole is located at the center of the base.

7. A fingertip force sensing device according to claim 3, characterized in that, The horizontal connecting section is semi-circular in shape.

8. A fingertip force sensing device according to any one of claims 1-7, characterized in that, The force-receiving part includes a plurality of independent force-receiving sub-parts arranged along its length direction. Each force-receiving sub-part is connected to the finger base through a corresponding elastic connector and is equipped with a corresponding first detection element and second detection element.

9. A fingertip force sensing device according to claim 1, characterized in that, It also includes a wrapping layer that covers the outside of the finger base and the force-bearing part.

10. A dexterous hand, characterized in that, Includes the fingertip force sensing device as described in any one of claims 1-9.

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