Force sensor for manipulator and robot
By designing a force sensor with a shell and a two-dimensional force sensor, the gap and cavity structure are used to improve the deformation sensitivity of mechanically sensitive elements, the problem of existing force sensors being not sensitive enough when measuring subtle force changes is achieved, and higher accuracy and protection effects are achieved.
Patent Information
- Application Number
- CN202422103684.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-29
- Publication Date
- 2025-06-24
- Estimated Expiration
- 2034-08-29
AI Technical Summary
Existing force sensors are not sensitive enough to measure subtle force changes to meet the accuracy requirements of the robot.
A force sensor for a robot is designed, including a housing and a two-dimensional force sensor, with a mechanically sensitive element running through the housing and a gap and a measuring element are provided on its outer wall. The measuring element detects forces in different directions through multiple strain gauges, and the cavity structure adds thinner parts on the mechanically sensitive element to improve deformation sensitivity.
The sensitivity of the force sensor is improved, so that it can more accurately detect subtle force changes on the robot, meet the accuracy requirements of the robot, and at the same time, the limiting and protective effects of the shell prevent excessive deformation.
Smart Images
Figure CN223013229U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of force sensors, and particularly to a force sensor for a manipulator and a robot. Background Art
[0002] A force sensor is a force sensor that can simultaneously sense forces and torque components in different directions, and is widely used in fields such as robots or manipulators. Existing force sensors, such as a split two-dimensional force sensor disclosed in a Chinese patent, measure the change of force by arranging strain gauges on a rectangular cross-section beam. However, in this structural form, the rectangular cross-section beam is a metal columnar structure, so a relatively large acting force is required to cause its deformation, and it is not sensitive to subtle force changes, so it cannot meet the requirements of the manipulator in terms of accuracy. Summary of the Utility Model
[0003] The utility model provides a force sensor for a manipulator and a robot, which is used to solve at least one of the above technical problems.
[0004] According to a first aspect of the utility model, the utility model provides a force sensor for a manipulator, including a housing and a two-dimensional force sensor, and the two-dimensional force sensor includes:
[0005] A mechanical sensitive element that penetrates the housing, and there is a gap between the outer wall of the mechanical sensitive element and the inner wall of the housing; and
[0006] A measuring element that is arranged on the outer wall of the mechanical sensitive element, and the measuring element can respectively detect the magnitudes of forces in two different directions. Wherein, a cavity structure that penetrates the mechanical sensitive element is further arranged at the position of the mechanical sensitive element where the measuring element is located.
[0007] For further optimization of the technical solution of the utility model, the measuring element includes a plurality of first strain gauges and a plurality of second strain gauges. The plurality of first strain gauges are used to detect the magnitude and / or change of the force in the first direction, and the plurality of second strain gauges are used to detect the magnitude of the force in the second direction;
[0008] Wherein, two of the plurality of first strain gauges are respectively arranged on two opposite outer walls of the mechanical sensitive element, and two of the plurality of second strain gauges are respectively arranged on the other two opposite outer walls of the mechanical sensitive element, and the first strain gauges and the second strain gauges are staggered with each other in the extending direction of the mechanical sensitive element.
[0009] For further optimization of the technical solution of the present utility model, the cavity structure includes a first cavity structure and a second cavity structure. The first cavity structure is located between two relatively arranged first strain gauges and penetrates the mechanical sensitive element along the second direction; the second cavity structure is located between two relatively arranged pairs of second strain gauges and penetrates the mechanical sensitive element along the first direction.
[0010] For further optimization of the technical solution of the present utility model, the first cavity structure is configured as one or more of a circular hole, a square hole, an oval hole, and a long strip hole that penetrate the mechanical sensitive element along the second direction.
[0011] For further optimization of the technical solution of the present utility model, the second cavity structure is configured as one or more of a circular hole, a square hole, an oval hole, and a long strip hole that penetrate the mechanical sensitive element along the first direction.
[0012] For further optimization of the technical solution of the present utility model, two first strain gauges among multiple first strain gauges and two second strain gauges among multiple second strain gauges are connected by a bridge circuit.
[0013] For further optimization of the technical solution of the present utility model, one second strain gauge among multiple second strain gauges is also connected to a wire.
[0014] For further optimization of the technical solution of the present utility model, a force-bearing structure is provided at the top of the mechanical sensitive element. The force-bearing structure is fixedly connected to the mechanical sensitive element and is located outside the housing.
[0015] For further optimization of the technical solution of the present utility model, the gap between each outer sidewall of the mechanical sensitive element and the corresponding inner wall of the housing is 0.5 mm - 10 mm, and the lower side of the mechanical sensitive element is connected to the housing through a connecting member.
[0016] According to the second aspect of the present utility model, the present utility model provides a robot, including multiple mechanical hands, and the fingers of the mechanical hands are provided with the above-mentioned force sensor for the mechanical hands.
[0017] Compared with the prior art, the advantages of the present utility model are as follows:
[0018] (1) Since the mechanical sensitive element is also provided with a cavity structure that penetrates the mechanical sensitive element at the position where the measuring element is located, that is to say, the part of the mechanical sensitive element at the position where the measuring element is located is thinner, the mechanical sensitive element is more likely to deform under the action of force, and thus is more easily detected by the measuring element, improving the sensitivity of the measuring element.
[0019] (2) Since a housing is also provided outside the mechanical sensitivity element, the housing can play a role in limiting and protecting. On the one hand, there is a gap between the outer side wall of the mechanical sensitivity element and the inner wall of the housing, so the maximum deformation range of the mechanical sensitivity element is within this gap range, thus the deformation range of the mechanical sensitivity element can be limited; on the other hand, when the mechanical sensitivity element is subjected to a large force and generates a large deformation, the outer side wall of the mechanical sensitivity element will contact the inner wall of the housing, thereby preventing further deformation of the mechanical sensitivity element, so as to play a role in protecting the mechanical sensitivity element. Description of the Drawings
[0020] Hereinafter, the present utility model will be described in more detail based on embodiments with reference to the drawings.
[0021] Figure 1 is a three-dimensional structural schematic diagram of a force sensor for a manipulator in an embodiment of the present utility model;
[0022] Figure 2 is an exploded view of a force sensor for a manipulator in an embodiment of the present utility model;
[0023] Figure 3 is a three-dimensional front view of a mechanical sensitivity element installed in a housing in an embodiment of the present utility model;
[0024] Figure 4 is Figure 3 a cross-sectional view taken at A-A;
[0025] Figure 5 is a three-dimensional structural schematic diagram of a mechanical sensitivity element in an embodiment of the present utility model;
[0026] Figure 6 is a cross-sectional view of a mechanical sensitivity element in an embodiment of the present utility model.
[0027] Reference Signs:
[0028] 1. Housing; 11. Countersunk Hole;
[0029] 2. Two-Dimensional Force Sensor; 3. Conducting Wire; 4. Force-Receiving Structure;
[0030] 41. Fastener; 42. Fixing Hole;
[0031] 5. Connecting Piece;
[0032] 21. Mechanical Sensitivity Element; 211. First Connecting Hole; 212. Second Connecting Hole;
[0033] 22. Measuring Element; 23. First Cavity Structure; 24. Second Cavity Structure;
[0034] 221. First Strain Gauge; 222. Second Strain Gauge. Detailed implementation mode
[0035] The present utility model will be further described below in conjunction with the accompanying drawings.
[0036] As shown in Figures 1 - 6 , according to the first aspect of the present utility model, the present utility model provides a force sensor for a manipulator, including a housing 1 and a two-dimensional force sensor 2. The two-dimensional force sensor 2 includes a mechanical sensitive element 21 penetrating the housing 1 and a measuring element 22 arranged on the outer side wall of the mechanical sensitive element 21. The measuring element 22 can respectively detect the magnitude and / or change of forces in two different directions.
[0037] Specifically, as shown in Figure 1 and Figure 2 , the measuring element 22 includes a plurality of first strain gauges 221 and a plurality of second strain gauges 222.
[0038] The plurality of first strain gauges 221 can be, for example, two or more. Two first strain gauges 221 can be matched into a first strain gauge pair for detecting the magnitude and / or change of the force in the first direction. Please refer to Figure 4 , the first direction is Figure 4 the X direction shown in . The first direction can be, for example, the width direction of the mechanical sensitive element 21. That is to say, when the mechanical sensitive element 21 is subjected to a positive or negative force in the X direction, each first strain gauge 221 can detect the magnitude and / or change of the force in this direction.
[0039] The plurality of second strain gauges 222 can be, for example, two or more. Two second strain gauges 222 can be matched into a second strain gauge pair for detecting the magnitude and / or change of the force in the second direction. Please refer to Figure 6 , the second direction is Figure 6 the Y direction shown in . The second direction can be, for example, the thickness direction of the mechanical sensitive element 21. That is to say, when the mechanical sensitive element 21 is subjected to a positive or negative force in the Y direction, each second strain gauge 222 can detect the magnitude and / or change of the force in this direction.
[0040] Therefore, it can be understood that the first direction and the second direction are perpendicular to each other.
[0041] As shown in Figure 1 and Figure 2 , two of the plurality of first strain gauges 221 are respectively arranged on two opposite outer side walls of the mechanical sensitive element 21, and these two outer side walls are oppositely arranged in the first direction (i.e., the X direction). As shown in Figure 1As shown, the first strain gauges 221 on two outer sidewalls oppositely arranged in the first direction (i.e., the X direction) can be symmetrically arranged with respect to the mechanical sensitive element 21.
[0042] Two of the plurality of second strain gauges 222 are respectively arranged on two other opposite outer sidewalls of the mechanical sensitive element 21, and these two outer sidewalls are oppositely arranged in the second direction (i.e., the Y direction). As Figure 2 shown, the second strain gauges 222 on two outer sidewalls oppositely arranged in the second direction (i.e., the Y direction) can be slightly staggered. Of course, the two can also be symmetrically arranged with respect to the mechanical sensitive element 21.
[0043] Figure 1 and Figure 2 shows a structural form in which the mechanical sensitive element 21 is a cuboid or a cube. It can be understood that the mechanical sensitive element 21 can also be in a cylindrical structural form. For the case where the mechanical sensitive element 21 is in a cylindrical structural form, the two first strain gauges 221 can be arranged in a manner of being spaced 180° in the circumferential direction of the mechanical sensitive element 21, the two second strain gauges 222 can be arranged in a manner of being spaced 180° in the circumferential direction of the mechanical sensitive element 21, and the first strain gauges 221 and the second strain gauges 222 are arranged alternately in the circumferential direction of the mechanical sensitive element 21.
[0044] Since there is a gap between the outer sidewall of the mechanical sensitive element 21 and the inner wall of the housing 1, that is, the mechanical sensitive element 21 has a certain movement space in the housing 1. Therefore, when the mechanical sensitive element 21 generates strain under the action of force, this strain can be detected by the plurality of first strain gauges 221 and the plurality of second strain gauges 222 through electrical signals.
[0045] In addition, the purpose of arranging the housing 1 outside the mechanical sensitive element 21 is also that the housing 1 can play a role of limiting and protecting. On the one hand, there is a gap between the outer sidewall of the mechanical sensitive element 21 and the inner wall of the housing 1, then the maximum deformation range of the mechanical sensitive element 21 is within this gap range. In other words, the maximum deformation range of the mechanical sensitive element 21 is when it deforms until the outer sidewall of the mechanical sensitive element 21 contacts the inner wall of the housing 1. Therefore, it can be seen that the housing 1 can limit the deformation range of the mechanical sensitive element 21. On the other hand, when the mechanical sensitive element 21 is subjected to a large force and generates a large deformation, the outer sidewall of the mechanical sensitive element 21 will contact the inner wall of the housing 1, thereby preventing further deformation of the mechanical sensitive element 21, so as to play a role in protecting the mechanical sensitive element 21.
[0046] The multiple first strain gauges 221 and the multiple second strain gauges 222 can both be resistance foils made of metal wires or foils with relatively high resistance. They can be used to sense expansion and contraction and generate positive or negative signals to distinguish between the two. The multiple first strain gauges 221 can be respectively pasted on two opposite outer sidewalls of the mechanical sensitive element 21. Similarly, the multiple second strain gauges 222 can be respectively pasted on the other two opposite outer sidewalls of the mechanical sensitive element 21, and the first strain gauges 221 and the second strain gauges 222 are staggered from each other in the extending direction of the mechanical sensitive element 21.
[0047] Further, a cavity structure is also provided at the position of the mechanical sensitive element 21 where the measuring element 22 is located. As Figure 3 、 4 、 Figure 5 and Figure 6 shown, the cavity structure includes a first cavity structure 23 and a second cavity structure 24. Please combine Figure 1 , the first cavity structure 23 is located between two relatively arranged first strain gauges 221 and penetrates through the mechanical sensitive element 21 along the second direction (i.e., the Y direction); the second cavity structure 24 is located between two pairs of relatively arranged second strain gauges 222 and penetrates through the mechanical sensitive element 21 along the first direction (i.e., the X direction).
[0048] That is to say, the part of the mechanical sensitive element 21 located between the two first strain gauges 221 is the first cavity structure 23. Due to the existence of the first cavity structure 23, the thickness of the first mechanical sensitive element 21 at this position is thinner, so it is easier to generate deformation, and thus it is more easily detected by the two first strain gauges 221, improving the sensitivity of the measuring element 22.
[0049] Specifically, the first cavity structure 23 is configured as one or more of an eight-shaped hole, a circular hole, a square hole, an oval hole, and a long strip hole that penetrates through the mechanical sensitive element 21 along the second direction (i.e., the Y direction). As Figure 5 and Figure 6 shown, the first cavity structure 23 includes two circular holes on both sides and a square hole in the middle, and the holes communicate with each other.
[0050] It can be understood that the purpose of the first cavity structure 23 is to remove part of the material of the mechanical sensitive element 21 located between the two first strain gauges 221, making the part of the mechanical sensitive element 21 located between the two first strain gauges 221 thinner, so as to facilitate the deformation of the mechanical sensitive element 21. Therefore, the first cavity structure 23 can also be other suitable structural forms.
[0051] Similarly, the second cavity structure 24 is configured to penetrate through the mechanical sensitive element 21 in the first direction in one or more of an eight-shaped hole, a circular hole, a square hole, an oval hole, and a long strip hole. As Figure 4 and Figure 5 shown, the second cavity structure 24 includes two circular holes located on both sides and a square hole located in the middle, and the holes communicate with each other.
[0052] It can be understood that the purpose of the second cavity structure 24 is to remove part of the material on the mechanical sensitive element 21 between the two second strain gauges 222, so that the part of the mechanical sensitive element 21 between the two second strain gauges 222 is thinner, facilitating the deformation of the mechanical sensitive element 21. Therefore, the second cavity structure 24 can also be other suitable structural forms.
[0053] In addition, the length of the two first strain gauges 221 is at least greater than 1 / 2 of the length of the first cavity structure 23. Preferably, the length of the two first strain gauges 221 is the same as the length of the first cavity structure 23. That is to say, the first strain gauges 221 can completely cover the first cavity structure 23 to further improve the sensitivity of its detection.
[0054] Wherein, the length of the first strain gauge 221 is the dimension in the extending direction of the mechanical sensitive element 21, that is Figure 4 and Figure 6 shown in the Z direction dimension.
[0055] As Figure 2 shown, two of the multiple first strain gauges 221 and two of the multiple second strain gauges 222 are connected by a bridge circuit (such as a Wheatstone full bridge circuit) to accurately measure the unknown resistance and differences. One of the multiple second strain gauges 222 is also connected to a wire 3 extending outside the housing 1. Through the wire 3, the positive or negative signals detected by each strain gauge can be output outward, and through the action of A / D conversion and amplification, the corresponding strain value is converted into a voltage value to complete the measurement of the two-dimensional force.
[0056] As Figure 2 shown, a force-bearing structure 4 is provided at the top of the mechanical sensitive element 21. The force-bearing structure 4 is fixedly connected to the mechanical sensitive element 21 and is located outside the housing 1. Specifically, as Figure 4 shown, a first connection hole 211 is provided at the top of the mechanical sensitive element 21. The force-bearing structure 4 can be, for example, a block structure, and a fixing hole 42 penetrating through it is provided on the force-bearing structure 4. Therefore, the force-bearing structure 4 can be fixed to the top of the mechanical sensitive element 21 through a fastener 41 such as a bolt.
[0057] The force-bearing structure 4 can bear pressure or tension and transmit the externally applied pressure or tension thereto to the mechanical sensitive element 21, so that each strain gauge on the mechanical sensitive element 21 can detect and obtain the magnitude of the force.
[0058] As Figure 3 and Figure 4 shown, the gap d between each outer side wall of the mechanical sensitive element 21 and the corresponding inner wall of the housing 1 is 0.5 mm - 10 mm. That is to say, the mechanical sensitive element 21 can be centered inside the housing 1, so that the gaps d between the four side walls of the mechanical sensitive element 21 and the corresponding four inner walls of the housing 1 are equal. Since there is a gap between the outer side wall of the mechanical sensitive element 21 and the inner wall of the housing 1, the mechanical sensitive element 21 can deform in the first direction (i.e., the X direction) and the second direction (i.e., the Y direction) in the housing 1 when stressed without being affected by the housing 1.
[0059] As Figure 1 and Figure 2 shown, the mechanical sensitive element 21 is fixedly connected to the housing 1 through the connecting member 5. Specifically, as Figure 4 shown, one or more second connection holes 212 are provided at the lower end of the mechanical sensitive element 21, and counterbore holes 11 are provided at the corresponding positions of the housing 1. The connecting member 5 (such as a bolt or a screw) passes through the counterbore holes 11 on the housing 1 and is connected to the corresponding second connection holes 212 on the mechanical sensitive element 21, thereby fixedly connecting the lower side of the mechanical sensitive element 21 to the housing 1.
[0060] It can be understood that the force-bearing structure 4 is provided at the top end of the mechanical sensitive element 21, and its lower side is fixedly connected to the housing 1 through the connecting member 5. Therefore, the mechanical sensitive element 21 forms a structure similar to a cantilever, so that when the force-bearing structure 4 is subjected to a force, the mechanical sensitive element 21 can deform more easily and be detected by each strain gauge.
[0061] According to the second aspect of the present invention, the present invention also provides a robot, including a plurality of mechanical hands, and the fingers of the mechanical hands are provided with the above-mentioned force sensors for the mechanical hands. In addition, the robot may further include structures for realizing its various functions, which are not described in detail in the present invention. The structure of the fingers of the mechanical hands can adopt various existing structures of robot fingers or electronic fingers, which are not described in detail in the present invention.
[0062] Although the present utility model has been described with reference to the preferred embodiments, various modifications thereof can be made and components thereof can be replaced with equivalents without departing from the scope of the present utility model. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any manner. The present utility model is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.
Claims
1. A force sensor for a manipulator, characterized in that: The invention comprises a housing and a two-dimensional force sensor, wherein the two-dimensional force sensor comprises: a mechanical sensing element, which penetrates the shell, and a gap is formed between an outer wall of the mechanical sensing element and an inner wall of the shell; and A measuring element is arranged on the outer side wall of the mechanical sensitive element, and the measuring element can respectively detect the magnitude of force and / or force change in two different directions, wherein the mechanical sensitive element is also provided with a cavity structure penetrating the mechanical sensitive element at the position where the measuring element is located.
2. The force sensor for a manipulator according to claim 1, characterized in that: The measuring element includes a plurality of first strain gauges and a plurality of second strain gauges, wherein the plurality of first strain gauges are used to detect the magnitude of the force in the first direction, and the plurality of second strain gauges are used to detect the magnitude of the force in the second direction; Among them, two first strain gauges among the multiple first strain gauges are respectively arranged on two opposite outer side walls of the mechanical sensitive element, and two second strain gauges among the multiple second strain gauges are respectively arranged on the other two opposite outer side walls of the mechanical sensitive element, and the first strain gauge and the second strain gauge are staggered with each other in the extension direction of the mechanical sensitive element.
3. The force sensor for a robot according to claim 2, characterized in that: The cavity structure includes a first cavity structure and a second cavity structure. The first cavity structure is located between two first strain gauges arranged opposite to each other and penetrates the mechanical sensitive element along the second direction; the second cavity structure is located between two second strain gauge pairs arranged opposite to each other and penetrates the mechanical sensitive element along the first direction.
4. The force sensor for a robot according to claim 3, characterized in that: The first cavity structure is configured as one or more of a circular hole, a square hole, an elliptical hole and a long strip hole penetrating the mechanical sensitive element along the second direction.
5. The force sensor for a robot according to claim 3, characterized in that: The second cavity structure is configured as one or more of a circular hole, a square hole, an elliptical hole and a long strip hole penetrating the mechanical sensitive element along the first direction.
6. The force sensor for a manipulator according to any one of claims 2 to 5, characterized in that: Two first strain gauges among the plurality of first strain gauges and two second strain gauges among the plurality of second strain gauges are connected by a bridge circuit.
7. The force sensor for a manipulator according to any one of claims 2 to 5, characterized in that: One of the plurality of second strain gauges is also connected to the wire.
8. The force sensor for a manipulator according to any one of claims 1 to 5, characterized in that: A force-bearing structure is arranged at the top of the mechanical sensitive element, the force-bearing structure is fixedly connected to the mechanical sensitive element, and the force-bearing structure is located outside the shell.
9. The force sensor for a manipulator according to any one of claims 1 to 5, characterized in that: The gap between each outer side wall of the mechanical sensitive element and the corresponding inner wall of the shell is 0.5mm-10mm, and the lower side of the mechanical sensitive element is connected to the shell through a connecting piece.
10. A robot, characterized in that: It comprises a plurality of manipulators, fingers of which are provided with force sensors for the manipulators according to any one of claims 1 to 9.