Multi-dimensional force sensing unit and sensor based on tip stress concentration effect

Abstract

The invention provides a multi-dimensional force sensing unit and a sensor based on a tip stress concentration effect, and the unit comprises a stress beam which is provided with a deformation gap, one end of the deformation gap extends to the middle part of the stress beam and protrudes outwards, and when the stress beam is in a static state, the extension tail end of the deformation gap is of an arc-shaped structure; when the stress beam is in a stress state, the extending tail end of the deformation gap forms a gap tip structure; the force sensitive layer is connected to the surface of the stress beam and arranged around the deformation gap; and the electrode is connected to the force sensitive layer. According to the invention, the response speed and quality of the force-sensitive layer can be greatly improved, and the signal detection sensitivity can be ensured even if the force-sensitive layer is subjected to weak force or dynamic change force. Compared with a conventional sensor at the present stage, the sensor has the advantages of being rapid in feedback, accurate in recognition, wide in application range, convenient to produce and prepare and the like, and a new thought is provided for development of the sensor.

Description

Technical Field

[0001] The present invention relates to the field of sensing technology, and in particular to a multi-dimensional force-sensitive unit and a sensor based on tip stress concentration effect. Background Art

[0002] In today's robotics field, the flexibility of robots has been significantly improved, mainly due to the introduction and optimization of joint mechanisms. In order to achieve precise control of robot movements, mechanical sensors at the joints have become key components. They can achieve force control and closed-loop feedback, thereby improving the performance of robots. However, with the complexity of application scenarios and the multidimensionality of requirements, traditional single-dimensional and three-dimensional sensors can no longer meet market demand, and the research and development of multi-dimensional sensor technology is particularly important.

[0003] At present, the resistive patch method still occupies a dominant position in the technical solutions of mechanical sensor units. The stability of this method has been widely recognized in the industry. Both the error rate and environmental factors have relatively little impact on it, and it has good controllability. However, although this design is ideal in theory, its structural design has stagnated for a long time. In the existing structural design, the force beam and the force-sensitive unit exist independently, and signals such as deformation are transmitted to sensors such as resistance strain gauges. Although this design guarantees the performance of the sensor to a certain extent, it also brings a series of problems.

[0004] The most prominent problem is that the force beams in force-sensitive sensors generally use traditional materials and designs, which are often not deformed enough to produce a strong enough signal output when subjected to external forces. This deformation limitation results in the signal response of the force-sensitive unit being insensitive when detecting weak or dynamically changing forces, thereby reducing the overall detection efficiency.

[0005] In addition, the existing force beams have a slow response speed in dynamic environments and cannot meet the real-time monitoring requirements of rapidly changing force signals. This lack of response speed limits the application of force sensors in high-speed motion control, robot perception and other fields. At the same time, the processing technology of the force beam is complex and requires high-precision processing equipment and technology, which not only increases the production cost, but also limits the large-scale application of force sensors. Summary of the invention

[0006] To this end, the technical problem to be solved by the present invention is to overcome the problem of low response speed and low accuracy of force sensitive sensors in the prior art, and to provide a multi-dimensional force sensitive unit and sensor based on the tip stress concentration effect.

[0007] In order to solve the above technical problems, the present invention provides a multi-dimensional force-sensitive unit based on the tip stress concentration effect, which includes: a force-bearing beam, wherein at least one deformation gap is provided on the force-bearing beam, and the deformation gap extends along a first direction, one end of which is connected to the outside world, and the other end extends to the middle of the force-bearing beam and protrudes outward. When the force-bearing beam is in a stationary state, the side walls of the deformation gap are arranged parallel to each other, and the extended end thereof is an arc structure; when the force-bearing beam is in a force-bearing state, the side walls of the deformation gap are close to each other, and the extended end thereof forms a gap tip structure; a force-sensitive layer, wherein the force-sensitive layer is connected to the surface of the force-bearing beam and is arranged around the deformation gap; and an electrode, wherein the electrode is connected to the force-sensitive layer.

[0008] In one embodiment of the present invention, the force-sensitive layer includes a substrate layer, a buried oxide layer and an active layer connected in sequence, wherein the substrate layer is connected to the force-bearing beam.

[0009] In one embodiment of the present invention, the thickness of the substrate layer is 450 μm, the thickness of the buried oxide layer is 2 μm, and the thickness of the active layer is 0.5 μm.

[0010] In one embodiment of the present invention, the substrate layer and the active layer substrate are both P-type silicon, the active layer is ion implanted, and the buried oxide layer substrate is silicon dioxide, so that the force-sensitive layer forms an N-type varistor.

[0011] In one embodiment of the present invention, the ion implantation conditions are: an implantation energy of 50 keV and a dose of 3×10 15 / cm 3 of nitrogen, maintained for 30 min and then annealed.

[0012] In one embodiment of the present invention, it also includes an insulating protective layer, which is connected to the force-bearing beam and is arranged around the edge of the force-sensitive layer.

[0013] In one embodiment of the present invention, the insulating protection layer is connected to the stress-bearing beam by thin film deposition technology.

[0014] In one embodiment of the present invention, the stress-bearing beam is one of engineering plastics, ceramic materials or composite materials; and the deformation gap is prepared by one of precision laser micromachining technology, ultrasonic microhole machining technology or femtosecond laser microhole machining technology.

[0015] In one embodiment of the present invention, it further includes a stress amplification component, which extends along the second direction, has two ends respectively connected to the side walls of the deformation gap, and bends with the deformation of the strain gap.

[0016] The present invention also provides a sensor, which includes the above-mentioned multi-dimensional force-sensitive unit based on the tip stress concentration effect.

[0017] The above technical solution of the present invention has the following advantages compared with the prior art: The multi-dimensional force-sensitive unit and sensor based on the tip stress concentration effect described in the present invention fully utilize the stress concentration effect of the tip structure of the slit by setting the deformation gap in the force-bearing beam, so that it can conduct force more quickly and accurately. At the same time, the force-sensitive layer can make the force-bearing structure also have a force-sensitive sensing function, thereby achieving more accurate and rapid feedback. In the above process, the force-bearing beam can directionally amplify the deformation, thereby greatly improving the response speed and quality of the force-sensitive layer, and can ensure the detection sensitivity of the signal even when it is subjected to weak force or dynamically changing force. Compared with conventional sensors at this stage, the present application has the advantages of rapid feedback, accurate identification, wide range of applications, and easy production and preparation, providing new ideas for the development of sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0019] Figure 1 It is a schematic diagram of the three-dimensional structure of a multi-dimensional force-sensitive unit based on the tip stress concentration effect in a static state in a preferred embodiment of the present invention; Figure 2 yes Figure 1 The schematic diagram of the three-dimensional structure of the multi-dimensional force-sensitive unit under stress state based on the tip stress concentration effect is shown; Figure 3 yes Figure 1 The schematic diagram of the structure of the force-sensitive layer in the multi-dimensional force-sensitive unit based on the tip stress concentration effect is shown; Figure 4 It is a schematic diagram of the three-dimensional structure of a sensor in another embodiment of the present invention.

[0020] Explanation of the reference numerals in the drawings in the specification: 100, stress-bearing beam; 110, deformation gap; 120, gap tip structure; 200, force-sensitive layer; 210, active layer; 220, buried oxide layer; 230, substrate layer; 300, electrode; 400, insulating protective layer; 500, stress amplification component; X, first direction; Y, second direction; Z, third direction. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention. Embodiment 1

[0022] See also Figure 1 and Figure 2 As shown, this embodiment provides a multi-dimensional force-sensitive unit based on the tip stress concentration effect, which includes: a force-bearing beam 100, wherein at least one deformation gap 110 is provided on the force-bearing beam 100, wherein the deformation gap 110 extends along a first direction X, wherein one end thereof is connected to the outside, and the other end extends to the middle of the force-bearing beam 100 and protrudes outward, and when the force-bearing beam 100 is in a stationary state, the side walls of the deformation gap 110 are arranged parallel to each other, and the extended ends thereof are in an arc-shaped structure; when the force-bearing beam 100 is in a force-bearing state, the side walls of the deformation gap 110 are close to each other, and the extended ends thereof form a gap tip structure 120; a force-sensitive layer 200, wherein the force-sensitive layer 200 is connected to the surface of the force-bearing beam 100 and is arranged around the deformation gap 110; and an electrode 300, wherein the electrode 300 is connected to the force-sensitive layer 200.

[0023] The multi-dimensional force-sensitive unit based on the tip stress concentration effect described in this embodiment makes full use of the stress concentration effect of the tip structure 120 through the setting of the deformation gap 110 in the force-bearing beam 100, so that it can conduct force more quickly and accurately. At the same time, the force-sensitive layer 200 can make the force-bearing structure also have a force-sensitive sensing function, thereby achieving more accurate and rapid feedback. In the above process, the force-bearing beam 100 can directionally amplify the deformation, thereby greatly improving the response speed and quality of the force-sensitive layer 200, and ensuring the detection sensitivity of the signal even when it is subjected to weak force or dynamically changing force. Compared with conventional sensors at this stage, the present application has the advantages of rapid feedback, accurate identification, wide application range and easy production and preparation, providing new ideas for the development of sensors.

[0024] It should be noted that, according to the research inspired by biological tissue structure, the slit tip structure 120 has a good stress concentration effect, and the stress at the tip position is fed back more quickly than other areas, and the force is sufficient and recognizable. Based on this principle, in this application, a deformation gap 110 is designed on the force-bearing beam 100 to cause it to deform itself during the force-bearing process, thereby causing the resistance of the local compression of the material to change, thereby achieving the purpose of combining deformation and force-sensitive sensing.

[0025] For ease of description, this embodiment defines the length direction of the multi-dimensional force-sensitive unit based on the tip stress concentration effect as the first direction X, the width direction of the multi-dimensional force-sensitive unit based on the tip stress concentration effect as the second direction Y, and the height direction of the multi-dimensional force-sensitive unit based on the tip stress concentration effect as the third direction Z, wherein the first direction X, the second direction Y and the third direction Z are mutually perpendicular, and the first direction X and the second direction Y are located in the same plane. Furthermore, the force-bearing beam 100 of the nurse Li Zhang bears the force in the second direction Y, thereby forming a seam tip structure 120.

[0026] In this embodiment, the stress beam 100 is an engineering plastic, which can also be configured as a ceramic material or a composite material; the deformation gap 110 is prepared by one of precision laser micromachining technology, ultrasonic micro-hole machining technology or femtosecond laser micro-hole machining technology, and the present invention does not make specific restrictions on this. Further, the plane size of the stress beam 100 in this embodiment is 3mm×1mm, and the specific shape of the seam tip structure 120 needs to be specifically analyzed and set according to the shape and size of the stress beam 100, the stress detection range and the sensitivity.

[0027] In this embodiment, in order to improve the insulation performance of the force-bearing beam 100 and ensure the stability and safety during use, this embodiment further provides an insulating protective layer 400, which is connected to the force-bearing beam 100 and is provided around the edge of the force-sensitive layer 200. Specifically, the insulating protective layer 400 is connected to the force-bearing beam 100 by thin film deposition technology.

[0028] See also Figure 3 As shown, in this embodiment, the force-sensitive layer 200 includes a substrate layer 230, a buried oxide layer 220 and an active layer 210 connected in sequence, wherein the substrate layer 230 is connected to the force-bearing beam 100. Specifically, the thickness of the substrate layer 230 is 450 μm, the thickness of the buried oxide layer 220 is 2 μm, and the thickness of the active layer 210 is 0.5 μm. Furthermore, in this embodiment, the substrates of the substrate layer 230 and the active layer 210 are both P-type silicon, the active layer 210 is ion-implanted, and the substrate of the buried oxide layer 220 is silicon dioxide, so that the force-sensitive layer 200 forms an N-type varistor. The ion implantation conditions are: the implantation energy is 50 keV and the dose is 3×10 15 / cm 3 The nitrogen gas is maintained for 30 minutes and then annealed. Then, the seam tip structure 120 has a resistor by connecting the electrode 300, and its resistance value can be changed in response to the force beam 100. Specifically, the electrode 300 in this embodiment is connected to the force sensitive layer 200 by electroplating.

[0029] In this embodiment, when the stress beam 100 is subjected to a small force or a tensile force in the second direction Y, the degree of stress concentration is not obvious. Therefore, the present application also includes a stress amplifier 500, which extends along the second direction Y, and its two ends are respectively connected to the side walls of the deformation gap 110, and bends with the deformation of the strain gap. Furthermore, the stress amplifier 500 in this embodiment is a flexible and tear-resistant filament. When the tensile force on the stress beam 100 exceeds the load, the operator can quickly judge the state of the force-sensitive layer 200 by setting the deformation of the stress amplifier 500 to break. Embodiment 2

[0030] This embodiment provides a sensor, which is a six-dimensional force sensor with a three-spoke beam structure, and includes a plurality of multi-dimensional force-sensitive units based on the tip stress concentration effect described in the first embodiment. Figure 4 The structure of one of the spokes is shown. Furthermore, in this embodiment, the multidimensional force-sensitive units based on the tip stress concentration effect arranged on the same side of the spoke can be set in different directions, thereby achieving a three-dimensional response effect. Specifically, in this embodiment, the two multidimensional force-sensitive units based on the tip stress concentration effect arranged relatively on the same side of the spoke can form mutually corroborating and complementary data through their opposite force forms when subjected to forces in different directions. In different implementations, the connection position and direction of the multidimensional force-sensitive unit based on the tip stress concentration effect can be adaptively adjusted according to actual use requirements, and the present invention does not impose specific restrictions on this.

[0031] The multi-dimensional force-sensitive unit and sensor based on the tip stress concentration effect described in the present invention fully utilize the stress concentration effect of the tip structure 120 through the setting of the deformation gap 110 in the force-bearing beam 100, so that it can conduct force more quickly and accurately. At the same time, the force-sensitive layer 200 can make the force-bearing structure also have a force-sensitive sensing function, thereby achieving more accurate and rapid feedback. In the above process, the force-bearing beam 100 can directionally amplify the deformation, thereby greatly improving the response speed and quality of the force-sensitive layer 200, and can ensure the detection sensitivity of the signal even when it is subjected to weak force or dynamically changing force. Compared with conventional sensors at this stage, the present application has the advantages of rapid feedback, accurate identification, wide application range and easy production and preparation, providing new ideas for the development of sensors.

[0032] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A multi-dimensional force-sensitive unit based on tip stress concentration effect, characterized in that: include: A stress-bearing beam, wherein at least one deformation slit is provided on the stress-bearing beam, wherein the deformation slit extends along a first direction, one end of which is connected to the outside, and the other end of which extends to the middle of the stress-bearing beam and protrudes outward, and when the stress-bearing beam is in a stationary state, the side walls of the deformation slit are arranged parallel to each other, and the extended ends thereof are in an arc-shaped structure; when the stress-bearing beam is in a stress-bearing state, the side walls of the deformation slit are close to each other, and the extended ends thereof form a slit tip structure; A force-sensitive layer, the force-sensitive layer is connected to the surface of the force-bearing beam and is arranged around the deformation gap; An electrode is connected to the force-sensitive layer.

2. The multi-dimensional force-sensitive unit based on the tip stress concentration effect according to claim 1, characterized in that: The force-sensitive layer includes a substrate layer, a buried oxide layer and an active layer which are connected in sequence, wherein the substrate layer is connected to the force-bearing beam.

3. The multi-dimensional force-sensitive unit based on the tip stress concentration effect according to claim 2, characterized in that: The thickness of the substrate layer is 450 μm, the thickness of the buried oxide layer is 2 μm, and the thickness of the active layer is 0.5 μm.

4. The multi-dimensional force-sensitive unit based on tip stress concentration effect according to claim 2, characterized in that: The substrate layer and the active layer substrate are both P-type silicon, the active layer is ion-implanted, and the buried oxide layer substrate is silicon dioxide, so that the force-sensitive layer forms an N-type varistor.

5. The multi-dimensional force-sensitive unit based on tip stress concentration effect according to claim 4, characterized in that: The ion implantation conditions are: implantation energy of 50 keV and a dose of 3×10 15 / cm 3 of nitrogen, maintained for 30 min and then annealed.

6. The multi-dimensional force-sensitive unit based on tip stress concentration effect according to claim 1, characterized in that: It also includes an insulating protective layer, which is connected to the force-bearing beam and is arranged around the edge of the force-sensitive layer.

7. The multi-dimensional force-sensitive unit based on tip stress concentration effect according to claim 6, characterized in that: The insulating protection layer is connected to the stress-bearing beam by thin film deposition technology.

8. The multi-dimensional force-sensitive unit based on tip stress concentration effect according to claim 1, characterized in that: The stress-bearing beam is one of engineering plastics, ceramic materials or composite materials; the deformation gap is prepared by one of precision laser micro-machining technology, ultrasonic micro-hole machining technology or femtosecond laser micro-hole machining technology.

9. The multi-dimensional force-sensitive unit based on tip stress concentration effect according to claim 1, characterized in that: It also includes a stress amplification component, which extends along the second direction, has two ends respectively connected to the side walls of the deformation gap, and bends along with the deformation of the deformation gap.

10. A sensor, characterized in that: It comprises a multi-dimensional force-sensitive unit based on the tip stress concentration effect as described in any one of claims 1 to 9.

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