A piezoelectric tactile sensor based on the bionics principle of human skin
By adopting the principle of human skin bionics in the tactile sensor and using piezoelectric haptic sensors with non-planar structures and flexible materials, the problems of insufficient detection shear force and unreasonable structure in the prior art are solved, and high sensitivity and flexibility are achieved , simplifies the production process and reduces costs.
Patent Information
- Application Number
- CN201810319041.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2018-04-11
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2038-04-11
AI Technical Summary
Existing tactile sensors are difficult to meet the requirements of intelligent robots for flexibility, multidimensionality and versatility, especially the ability to detect shear forces is lagging, and the structure does not conform to human skin anatomy, and the production process is complex and the consistency is poor.
Design a piezoelectric tactile sensor based on the principle of human skin bionics. It uses a non-planar structure of upper and lower templates to combine with a piezoelectric film to increase contact area and sensitivity, and improve flexibility and sensitivity through flexible materials and inter-embedded structures. Use pressure Electrical films and electrodes achieve shear signal amplification.
It realizes amplification of weak force signals, improves sensitivity and flexibility, simplifies the structure and production process, and can identify the position and amplification function of shear forces, which is cheap and convenient to operate.
Smart Images
Figure CN108489643B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of tactile sensors, in particular to a piezoelectric tactile sensor based on the bionics principle of human skin. Background Art
[0002] For robots and other intelligent equipment, tactile perception is an important way to obtain the properties of external objects and contact information. However, compared with vision, hearing, smell and other perception and sensing technologies, the development of tactile sensors is still lagging behind.
[0003] Tactile sensors used in robots should have the ability to accurately detect three-dimensional forces in unknown environments and be highly flexible. However, most tactile sensors on the market currently cannot meet the requirements of intelligent robots for flexibility, multidimensionality, and versatility. In particular, the technology of tactile sensors that can simply detect normal forces is close to maturity, while the technology of tactile sensors that can detect shear forces is relatively lagging behind. Therefore, it is extremely important to develop tactile sensors similar to human skin, which is of great significance to the development of robotics technology and fields such as sports and rehabilitation medicine.
[0004] Document No. 201610267537.3 discloses an artificial skin flexible tactile sensor measuring device, comprising a bionic dermis tissue layer, a bionic epidermis tissue layer, a bionic subcutaneous tissue layer and an artificial skin attachment base, wherein three liquid-core PVDF piezoelectric polymer fibers are arranged in the bionic dermis tissue layer. Although the PVDF piezoelectric polymer fibers used in the bionic artificial skin can detect the shear force, they do not have the functional characteristics of amplifying the shear force signal. In addition, the structure of the invention does not conform to the anatomical structure of human skin. At the same time, the manufacturing process is complicated and the consistency is poor. Summary of the invention
[0005] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a piezoelectric tactile sensor based on the bionics principle of human skin.
[0006] The technical solution of the present invention to solve the technical problem is to provide a piezoelectric tactile sensor based on the bionics principle of human skin, characterized in that the sensor includes an upper template, a lower template, a piezoelectric film and an electrode; one surface of the upper template has a non-planar structure, and one surface of the lower template has a corresponding non-planar structure that completely matches the non-planar structure of the upper template, so that the upper template and the lower template are matched and inlaid with each other; the piezoelectric film is fixed between the upper template and the lower template; electrodes are installed on both sides of the piezoelectric film.
[0007] Compared with the prior art, the present invention has the following beneficial effects:
[0008] (1) The present invention proposes a piezoelectric tactile sensor based on the theory of human skin bionics. The structure is simple and novel. It proposes a three-dimensional wrinkled structure similar to the dermis of human skin, including non-planar interlocking structures such as rectangular structures, wave structures and trapezoidal structures in the X and Y directions. Compared with the planar structure, the contact area of the piezoelectric film is increased, which can amplify weak force signals and has high sensitivity; and it can also identify the position of the shear force.
[0009] (2) The upper and lower templates are made of flexible materials, which make them highly flexible and easy to bend. The softness of the material is closer to human skin and has a high similarity.
[0010] (3) The interlocking structures used are diverse, and the patterning process is simple and inexpensive.
[0011] (4) The use of piezoelectric film has the advantages of high sensitivity and short response time.
[0012] (5) The device for assisting in verifying the shear force amplification function of the sensor proposed in the present invention has a simple structure, good manufacturability, convenient operation, and low cost, and can assist in verifying that the tactile sensor has a shear force amplification effect. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 This is a schematic diagram of a piezoelectric tactile sensor according to an embodiment of the present invention based on the principle of human skin bionics, in which the cross section of the sensor is a rectangular structure;
[0014] Figure 2 This is a schematic diagram of a piezoelectric tactile sensor according to an embodiment of the present invention based on the principle of human skin bionics, in which the cross section of the sensor is a wave structure;
[0015] Figure 3 A schematic diagram of a piezoelectric tactile sensor according to an embodiment of the present invention based on the principle of human skin bionics, in which the cross section of the sensor is a trapezoidal structure;
[0016] Figure 4 A schematic diagram of detecting the shear force contact position of a piezoelectric tactile sensor according to an embodiment of the present invention based on the human skin bionics principle;
[0017] Figure 5 A physical diagram of the shear force contact position of a piezoelectric tactile sensor according to an embodiment of the present invention based on the human skin bionics principle;
[0018] Figure 6This is a schematic diagram of the structure of a device for assisting in verifying the shear force amplification function of a piezoelectric tactile sensor according to an embodiment of the present invention based on the principle of human skin bionics. (In the figure: 1, upper template; 2, lower template; 3, piezoelectric film; 4, electrode; 5, base; 6, gravity loading; 7, bracket; 8, pulley; 9, upper plate; 10, lower plate; 11, winding pulley; 12, pressure rod; 13, flexible template; 14, winding;) DETAILED DESCRIPTION
[0019] The specific embodiments of the present invention are given below. The specific embodiments are only used to further illustrate the present invention in detail and do not limit the protection scope of the claims of this application.
[0020] The present invention provides a piezoelectric tactile sensor based on the bionics principle of human skin (see Figure 1-3 , referred to as sensor), characterized in that the sensor includes an upper template 1, a lower template 2, a piezoelectric film 3 and an electrode 4; one surface of the upper template 1 has a non-planar two-dimensional or three-dimensional structure, and one surface of the lower template 2 has a corresponding non-planar two-dimensional or three-dimensional structure that completely matches the non-planar two-dimensional or three-dimensional structure of the upper template 1, so that the upper template 1 and the lower template 2 are matched and inlaid with each other; the cross-section of the interface between the upper template 1 and the lower template 2 is in a non-planar state; the piezoelectric film 3 is fixed between the upper template 1 and the lower template 2 to form a three-layer structure; electrodes 4 are installed on both sides of the piezoelectric film 3, and the piezoelectric film 3 is connected to an external charge amplifier through the electrodes 4.
[0021] The non-planar two-dimensional or three-dimensional structure is a convex-concave structure, specifically a rectangular structure, a wavy structure or a trapezoidal structure;
[0022] The upper template 1 and the lower template 2 are made of flexible materials, such as flexible resin or flexible rubber, which are easily deformable. Polydimethylsiloxane can be selected. The maximum thickness is 3 mm, and the minimum spacing between adjacent convex and concave structures is 0.5 mm.
[0023] Preferably, when it is necessary to detect the shear force contact position of the sensor, it is necessary to coat the lower surface of the upper template 1 and the upper surface of the lower template 2 with a conductive material; when the conductive material is coated on the surfaces of the upper template 1 and the lower template 2, it is necessary to coat it at intervals, and after the sensor is formed, there is an intersection between the conductive materials on the lower surface of the upper template 1 and the upper surface of the lower template 2; for example, the conductive material is coated at intervals in the horizontal direction on the lower surface of the upper template 1, and the conductive material is coated at intervals in the vertical direction on the upper surface of the lower template 2, and the two have an intersection; for another example, the conductive material is coated at intervals in the vertical direction on the lower surface of the upper template 1, and the conductive material is coated at intervals in the horizontal direction on the upper surface of the lower template 2, and the two have an intersection;
[0024] The piezoelectric film 3 is a flexible conductive material with the characteristics of being thin, flexible, highly sensitive and fast in response, and can be made of PVDF material with a maximum thickness of 500um;
[0025] The present invention also provides a device for assisting in verifying the shear force amplification function of the sensor (hereinafter referred to as the device, see Figure 6 ), characterized in that the device includes a base 5, a gravity load 6, a bracket 7, a pulley 8, an upper plate 9, a lower plate 10, a winding pulley 11, a pressure rod 12, a flexible template 13 and a winding 14; the bracket 7 is fixed on the base 5; the pressure rod 12 is installed on the bracket 7 and can move up and down; one end of the pressure rod 12 is installed with a gravity load 6, and the other end is installed with a pulley 8 through an axis; the pulley 8 is in contact with the upper surface of the upper plate 9; the adjustment range of the gravity load 6 is 0 N-30N, used to apply preload; the preload is transmitted to the pulley 8 through the pressure rod 12, and the upper plate 9 is preloaded; the winding pulley 11 is installed on the base 5 through the shaft; one end of the winding 14 is connected to the external tensile testing machine, and the other end is connected to the upper plate 9 through the winding pulley 11, and the upper plate 9 is movable; the lower plate 10 is fixed on the base 5; the lower surface of the upper plate 9 and the upper surface of the lower plate 10 are both provided with a flexible template 13, and the middle of the flexible template 13 is the sensor. The flexible template 13 is made of rubber material;
[0026] The working principle and workflow of the piezoelectric tactile sensor based on the human skin bionics principle of the present invention are:
[0027] Verify the shear force amplification function of the sensor: rely on the gravity loading 6 of the device to provide preload force, so that the upper template 1 and the lower template 2 of the sensor are in contact with the two layers of flexible templates 13 respectively, and the upper plate 9 is connected to the tensile tester that applies shear force through the winding 14; when the tensile tester applies tension, the upper plate 9 and the lower plate 10 will move relative to each other, thereby driving the two layers of flexible templates 13 to move relative to each other, so that the upper surface of the upper template 1 is subjected to tangential force, resulting in a small displacement deformation, and the deformation of the upper template 1 will drive the deformation of the middle piezoelectric film 3, and the piezoelectric film 3 will be polarized due to deformation, thereby generating a charge signal. Since the upper template 1 and the lower template 2 adopt a non-planar structure, the piezoelectric film 3 in the middle is pressed into different fold structures, which will produce greater cumulative polarization under the action of shear force, and the charge signal generated will be greater than that of the planar structure. Therefore, this sensor can amplify the shear force signal with higher sensitivity.
[0028] Detect the shear force contact position of the sensor: Coat the conductive material on the lower surface of the upper template 1 and the upper surface of the lower template 2; when a shear force acts on a certain position of the upper template 1, the point will deform, and the piezoelectric film 3 below it will also deform, thereby generating an electrical signal. The position of the shear force is determined by the current at the intersection of the conductive materials of the upper template 1 and the lower template 2. The electrical signal at the point where the shear force acts is the strongest, and the electrical signals at other points are relatively weak. Figure 4 and Figure 5 As shown, when there is shear force in the circled area, the current at the intersection of the third conductive material coated longitudinally on the upper template 1 and the third conductive material coated transversely on the lower template 2, i.e. 3-3', is the largest, and the current at other positions is relatively small, thereby determining the shear force contact position.
[0029] Any matters not described in the present invention are applicable to the prior art.
Claims
1. A device for assisting in verifying the shear force amplification function of a sensor, characterized in that The device comprises a base, a gravity load, a bracket, a pulley, an upper plate, a lower plate, a winding pulley, a pressure rod, a flexible template and a winding; the bracket is fixed on the base; the pressure rod is installed on the bracket and can move up and down; one end of the pressure rod is installed with a gravity load, and the other end is installed with a pulley through an axis; the pulley contacts the upper surface of the upper plate; the winding pulley is installed on the base through an axis; one end of the winding is connected to an external tensile testing machine, and the other end is connected to the upper plate through the winding pulley, and the upper plate is movable; the lower plate is fixed on the base; the lower surface of the upper plate and the upper surface of the lower plate are both provided with flexible templates, and the middle of the flexible template is a piezoelectric tactile sensor based on the bionics principle of human skin; The sensor comprises an upper template, a lower template, a piezoelectric film and electrodes; one surface of the upper template has a non-planar structure, and one surface of the lower template has a corresponding non-planar structure that completely matches the non-planar structure of the upper template, so that the upper template and the lower template are mutually matched and inlaid and connected; the piezoelectric film is fixed between the upper template and the lower template; electrodes are installed on both sides of the piezoelectric film; the non-planar structure is a convex-concave structure; When it is necessary to detect the shear force contact position of the sensor, it is necessary to coat the lower surface of the upper template and the upper surface of the lower template with a conductive material; When the conductive material is coated on the surfaces of the upper template and the lower template, it needs to be coated at intervals. After the sensor is formed, there is a cross point between the conductive materials on the lower surface of the upper template and the upper surface of the lower template.
2. The device for assisting in verifying the shear force amplification function of the sensor according to claim 1, characterized in that The non-planar structure is a rectangular structure, a wavy structure or a trapezoidal structure.
3. The device for assisting in verifying the shear force amplification function of the sensor according to claim 1, characterized in that The minimum spacing between adjacent convex and concave structures is 0.5 mm.
4. The device for assisting in verifying the shear force amplification function of the sensor according to claim 1, characterized in that The materials of the upper template and the lower template are flexible resin or flexible rubber.
5. The device for assisting in verifying the shear force amplification function of the sensor according to claim 4, characterized in that The material of the upper template and the lower template is polydimethylsiloxane.
6. The device for assisting in verifying the shear force amplification function of the sensor according to claim 1, characterized in that The piezoelectric film is made of flexible conductive material.
7. The device for assisting in verifying the shear force amplification function of the sensor according to claim 6, characterized in that The piezoelectric film is made of PVDF.