Visual touch sensor device for mechanical arm safety cooperation

Abstract

The utility model discloses a visual touch sensor device for mechanical arm safety cooperation. According to the utility model, a flexible touch skin is tightly attached to the lower part of an S-curve lens, the side surface of the S-curve lens is provided with an LED illumination assembly, an RGB camera is fixedly installed above the S-curve lens, and the LED illumination assembly and the RGB camera are both connected with a control circuit board. When the flexible touch skin makes contact with an object, the flexible touch skin deforms after the object extrudes the flexible touch skin, light in the S-curve lens is refracted and projected to different degrees, the RGB camera collects a two-dimensional visual image corresponding to the object, and object sensing is completed. The visual touch sensor device can obtain abundant object surface information when a robot explores object and environment contact activities, the defect that visual perception of the robot is easily blocked by objects and interfered by light rays is overcome, and the operation precision of the robot is improved.

Description

Technical Field

[0001] The utility model belongs to a visual touch sensor in the field of robot perception, and in particular relates to a visual touch sensor device for safe collaboration of a robot arm. Background Art

[0002] With the rapid development of robotics technology, the new generation of industrial manufacturing requires the rapid production of customized products, so collaborative robots have entered industrial production and share the same operating space with workers. For the collaborative planning of robotic arms in limited spaces, robots are required to have sufficient autonomous perception and natural interaction capabilities. For robots that grab and place different objects, there are greater challenges in terms of their ability to perceive the texture of the surface of the objects when grabbing them, and the amount of force used to grab different objects. However, existing tactile sensors based on electrical signal transduction have the problem of generally low spatial resolution. In addition, a large number of electronic components and complex circuits will also bring defects such as signal crosstalk and hysteresis.

[0003] Therefore, it is necessary to design a tactile sensor with simple structure and circuit. Utility Model Content

[0004] In order to improve the perception ability of the end effector clamp of the robot arm when grasping objects, enable the end clamp of the robot arm to obtain rich surface texture feature information when grasping objects, and improve the safe collaboration ability of the robot arm and objects, the utility model provides a visual touch sensor device for safe collaboration of the robot arm.

[0005] In order to achieve the above technical purpose, the technical solution of the utility model is as follows:

[0006] The utility model includes a lens mounting frame; an S-curve lens, which is fixedly mounted in the lens mounting frame; a flexible tactile skin, the upper surface of which is fixedly mounted on the lower bottom surface of the S-curve lens; an LED lighting assembly, which is placed on the side of the S-curve lens; an intermediate support frame, which is fixedly mounted on the lens mounting frame; an RGB camera, which is fixedly mounted in the intermediate support frame, and the lens of the RGB camera faces the upper surface of the S-curve lens; a control circuit board, which is fixedly mounted in the intermediate support frame, and the control circuit board is connected to the RGB camera and the LED lighting assembly; and a cover, which is fixedly mounted on the intermediate support frame.

[0007] The lower bottom surface of the S-curve lens is completely covered by the upper surface of the flexible tactile skin.

[0008] The flexible tactile skin comprises a transparent elastic body and an opaque film, wherein the opaque film is attached to the lower surface of the transparent elastic body, and the upper surface of the transparent elastic body is closely attached to the lower bottom surface of the S-curve lens.

[0009] The LED lighting assembly includes three groups of LED lights and a flexible circuit board. The colors of the three groups of LED lights are red, green and blue respectively. The three groups of LED lights are arranged on the side of the S-curve lens. The three groups of LED lights are connected to the control circuit board through the flexible circuit board.

[0010] The flexible circuit board is arranged in a ring shape, and three groups of LED lights are respectively installed in the ring-shaped flexible circuit board at equal intervals along the circumference.

[0011] The three groups of LED lights are each composed of a plurality of LEDs arranged in an array.

[0012] The radiation intensities of the three groups of LED lights are the same.

[0013] The material of the S-curve lens is acrylic.

[0014] The lens mounting frame, the intermediate supporting frame and the sealing cover are all made of black photosensitive resin material.

[0015] The beneficial effects of the utility model are:

[0016] The visual touch sensor device of the utility model can obtain rich surface information of objects during the contact activities of the robot exploring objects and the environment, make up for the defect that the robot's visual perception is easily blocked by objects and disturbed by light, and improve the robot's operating accuracy.

[0017] The device of the utility model has a simple structure and is easy to disassemble and separate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a front view of the flexible tactile skin provided in an embodiment of the utility model;

[0019] Figure 2 Schematic diagram of an S-curve lens provided in an embodiment of the present utility model; wherein a is a B:B cross-sectional view of the S-curve lens, b is an axial side view of the S-curve lens, c is a front view of the S-curve lens, and d is an AA cross-sectional view of the S-curve lens;

[0020] Figure 3 An axonometric view of a lens mounting frame provided in an embodiment of the utility model;

[0021] Figure 4 A top view of a lens mounting frame provided in an embodiment of the utility model;

[0022] Figure 5A top view of the intermediate support frame provided in an embodiment of the utility model;

[0023] Figure 6 An exploded diagram of the structure of the visual touch sensor device provided by the utility model;

[0024] Figure 7 The working principle of the visual touch sensor device provided by the utility model Figure 1 ;

[0025] Figure 8 The working principle of the visual touch sensor device provided by the utility model Figure 2 ;

[0026] In the figure: 1. Flexible tactile skin, 2. S-curve lens, 3. Lens mounting frame, 4. LED lighting assembly, 5. Intermediate support frame, 6. Control circuit board, 7. RGB camera, 8. Cover, 9. Object, 10. Transparent elastomer, 11. Opaque film. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0028] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the purpose of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0029] like Figure 1 , Figure 3 , Figure 4 , Figure 5 and Figure 6As shown, the utility model includes a lens mounting frame 3; an S-curve lens 2, which is fixedly mounted in the lens mounting frame 3; and a flexible tactile skin 1, the upper surface of which is fixedly mounted on the lower bottom surface of the S-curve lens 2 by an adhesive; the lower bottom surface of the S-curve lens 2 is completely covered by the upper surface of the flexible tactile skin 1, that is, the area of ​​the lower bottom surface of the S-curve lens 2 is less than or equal to the area of ​​the upper surface of the flexible tactile skin 1. The lower surface of the flexible tactile skin 1 is in contact with an object to generate elastic deformation. The material of the S-curve lens 2 is acrylic. It also includes an LED lighting component 4, which is placed on the side of the S-curve lens 2; it also includes an intermediate support frame 5, which is fixedly mounted on the lens mounting frame 3; it also includes an RGB camera 7, which is fixedly mounted in the intermediate support frame 5, and the lens of the RGB camera 7 passes through the intermediate support frame 5 and the lens mounting frame 3 and faces the upper surface of the S-curve lens 2; it also includes a control circuit board 6, which is fixedly mounted in the intermediate support frame 5, specifically: the control circuit board 6 and the RGB camera 7 are respectively embedded in the annular groove and the center circular hole of the intermediate support frame 5, and the control circuit board 6 is connected to the RGB camera 7 and the LED lighting component 4; it also includes a cover 8, which is fixedly mounted on the intermediate support frame 5.

[0030] The flexible tactile skin 1 includes a transparent elastic body 10 and an opaque film 11. The opaque film 11 is attached to the lower surface of the transparent elastic body 10. The upper surface of the transparent elastic body 10 is tightly fitted with the lower bottom surface of the S-curve lens 2. The material of the transparent elastic body is Solaris. In order to allow the camera to capture the deformation information of the other side through the fixed side, it is necessary to ensure that the elastic body is transparent enough so as not to interfere with the reflection activity of the LED light on the opaque film.

[0031] The hardness of the elastomer determines its compliance and adaptability when in contact with an object. The smaller the hardness, the more sensitive the elastomer is to small contact forces, but it cannot withstand larger contact forces and some more intense contact activities. The greater the hardness, the greater the range of extrusion pressure that the elastomer can withstand, but the corresponding detection sensitivity will decrease, and the deformation characteristics will not be obvious. Therefore, appropriate hardness is required to ensure clear deformation characteristics in the tactile image and retain sufficient bearing capacity of the elastomer.

[0032] The thickness of the elastomer must be uniform enough to ensure that the tactile image is an orthographic projection of the sensing plane. The thickness of the elastomer is set to 1.5mm, which can basically meet the perception requirements of the sensor. In order to strictly ensure the uniform thickness of the elastomer, the mold consists of two semi-sealed cavities, and the inner cavity size of the mold is 120mm×115mm×1.5mm. The mold forms a large piece of silicone with uniform thickness at one time, and then the subsequent cutting steps ensure the plane size, so as to avoid the problem of warping of small-sized silicone molded in a single time during the subsequent curing and demolding process. The final size of the elastomer is

[0033] The transduction of tactile information by visual tactile sensors mainly relies on the design of flexible tactile skin, such as Figure 7 and Figure 8 As shown, when the object 9 comes into contact with the tactile skin, the transparent elastic body undergoes elastic deformation due to the restriction of the S-curve lens 2 fixed below. The degree of local deformation is related to the shape of the contact object, the physical properties of the elastic body itself, and the contact state. These deformations cause changes in the opaque film layer and changes in the reflected light, thereby recording tactile information. In a specific implementation, a certain pattern of marking patterns is printed on the surface of the tactile skin. When the elastic body is squeezed and deformed by the object, the marking pattern undergoes corresponding changes due to the stretching or compression deformation of the elastic body, which is intuitively manifested as a small displacement of each marking point. The magnitude and direction of the displacement directly correspond to the magnitude and direction of the external force applied to the tactile skin. The contact state of the object and the tactile skin can be determined by tracking the change process of the marking pattern with a camera. Uniformly irradiated LED light will be diffusely reflected on the inner surface of the reflective coating (i.e., parallel light projected on the surface will be reflected irregularly in all directions). When the elastomer is deformed by the object, the surface gradient of the local area of ​​the tactile skin surface will change accordingly, resulting in the reflection behavior of the light here being constrained and more reflected light being captured by the camera. The change in the intensity of the reflected light is reflected by the camera as a colored shadow on the image, which is obviously different from the projection of the diffuse reflected light in other areas where no deformation has occurred.

[0034] The shape of the S-curve lens 2 is as follows Figure 2 a, Figure 2 b. Figure 2 C and Figure 2 As shown in d, the shape of the S-curve lens 2 is similar to a "triangular pyramid with a truncated cone tip". In the "triangular pyramid with a truncated cone tip", the upper and lower surfaces are arranged in parallel and the upper surface area is larger than the lower surface area. A chamfer with an angle of θ is provided on the upper surface with the three sides of the triangular pyramid as the center, and the chamfer length is L; two arcs arranged up and down and intersecting the dividing surface are provided under the chamfer corresponding to each side. The radius of the first arc is R 2 , whose two edge lines are the plane where the chamfer line and the dividing surface are located; the radius of the second arc is R 1 The two edge lines are the plane where the dividing surface is located and the plane where the lower surface is located. The dividing surface (i.e., the BB section) is a regular triangle with a radius of R cut off at the three vertices. 3 The corresponding LED lamps are arranged on the three processed side surfaces of the S-curve lens 2, and the angle between the LED lamps and the upper surface of the triangular pyramid is θ.

[0035] The LED lighting assembly 4 includes three groups of LED lights and a flexible circuit board FPC. The colors of the three groups of LED lights are red, green and blue respectively. The three groups of LED lights are arranged on the side of the S-curve lens 2. The three groups of LED lights are connected to the control circuit board 6 through the flexible circuit board FPC. The control circuit board 6 is specifically an LED lighting power supply printed circuit board PCB. The three groups of LED lights are controlled to be on and off by the control circuit board 6. Among them, since the three groups of LEDs are arranged radially symmetrically and the flexible circuit board FPC itself is not firm, it will appear very messy and unsafe if all the lines are led to the outside. Therefore, in this embodiment, the flexible circuit board FPC is set to be ring-shaped, and the three groups of LED lights are respectively installed in the ring-shaped flexible circuit board FPC at equal intervals along the circumference. A lead line of the flexible circuit board FPC extends upward and is connected to the control circuit board 6. The three groups of LED lights are composed of multiple LEDs arranged in an array form (such as a 3×2 array), and the multiple LEDs are connected in parallel.

[0036] The specific working voltages of the three groups of red, green and blue LED lights are 1.95V, 2.70V and 2.85V respectively. Therefore, it is necessary to connect a voltage divider resistor in series to the external power supply circuit of the LED to adjust the working voltage of the three groups of LEDs to ensure that the S-curve lens 2 and the sensing plane receive uniform radiant illumination. The power supply of the LED lighting circuit is set to 5V. After continuous experimental adjustment, when the voltage divider resistors of the three groups of red, green and blue LEDs are 33Ω, 5Ω and 1Ω respectively, the average pixel intensity of the three channels on the tactile image is the closest.

[0037] The main purpose of the lens mounting frame 3, the intermediate support frame 5 and the cover 8 is to fix the lighting system, the camera and the flexible tactile skin, and to isolate the entire lighting system from external light sources to reduce interference. The lens mounting frame 3, the intermediate support frame 5 and the cover 8 are made of black photosensitive resin material and are integrally printed using a stereolithography device. The visual tactile sensor is cylindrical in shape and has a size of The mechanical structure is modularized into an upper and lower structure. The upper structure provides light-encoded contact information on the tactile skin, and the lower structure captures the tactile image and transmits it to the host computer, while providing power for the lighting system. The lens mounting frame 3, the intermediate support frame 5 and the cover 8 are connected by an internal mechanical interface and are easy to disassemble and separate.

[0038] The utility model utilizes the deformation of flexible tactile skin to change the principle of light imaging, and visualizes the sense of touch as a two-dimensional image, which can subsequently provide technical support for the intelligent development of robots.

[0039] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the present invention.

[0040] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present utility model will not further describe various possible combinations.

[0041] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A visual touch sensor device for safe collaboration of a robot arm, characterized in that: The invention comprises a lens mounting frame (3); an S-curve lens (2), wherein the S-curve lens (2) is fixedly mounted in the lens mounting frame (3); a flexible tactile skin (1), wherein the upper surface of the flexible tactile skin (1) is fixedly mounted on the lower bottom surface of the S-curve lens (2); an LED lighting assembly (4), wherein the LED lighting assembly (4) is placed on the side of the S-curve lens (2); an intermediate support frame (5), wherein the intermediate support frame (5) is fixedly mounted on the lens mounting frame (3); an RGB camera (7), wherein the RGB camera (7) is fixedly mounted in the intermediate support frame (5), wherein the lens of the RGB camera (7) faces the upper surface of the S-curve lens (2); a control circuit board (6), wherein the control circuit board (6) is fixedly mounted in the intermediate support frame (5), wherein the control circuit board (6) is connected to the RGB camera (7) and the LED lighting assembly (4); and a cover (8), wherein the cover (8) is fixedly mounted on the intermediate support frame (5).

2. A visual touch sensor device for safe collaboration of robotic arms according to claim 1, characterized in that: The lower bottom surface of the S-curve lens (2) is completely covered by the upper surface of the flexible tactile skin (1).

3. The visual touch sensor device for safe collaboration of robotic arms according to claim 1, characterized in that: The flexible tactile skin (1) comprises a transparent elastic body (10) and an opaque film (11), wherein the opaque film (11) is attached to the lower surface of the transparent elastic body (10), and the upper surface of the transparent elastic body (10) is tightly fitted to the lower bottom surface of the S-curve lens (2).

4. The visual touch sensor device for safe collaboration of robotic arms according to claim 1, characterized in that: The LED lighting assembly (4) comprises three groups of LED lights and a flexible circuit board. The colors of the three groups of LED lights are red light, green light and blue light respectively. The three groups of LED lights are arranged on the sides of the S-curve lens (2). The three groups of LED lights are connected to the control circuit board (6) via the flexible circuit board.

5. The visual touch sensor device for safe cooperation of robot arms according to claim 4, characterized in that: The flexible circuit board is arranged in a ring shape, and three groups of LED lights are respectively installed in the ring-shaped flexible circuit board at equal intervals along the circumference.

6. A visual touch sensor device for safe collaboration of robotic arms according to claim 5, characterized in that: The three groups of LED lights are each composed of a plurality of LEDs arranged in an array.

7. A visual touch sensor device for safe collaboration of robotic arms according to claim 5 or 6, characterized in that: The radiation intensities of the three groups of LED lights are the same.

8. The visual touch sensor device for safe collaboration of robotic arms according to claim 1, characterized in that: The material of the S-curve lens (2) is acrylic.

9. The visual touch sensor device for safe cooperation of robotic arms according to claim 1, characterized in that: The lens mounting frame (3), the intermediate support frame (5) and the sealing cover (8) are all made of black photosensitive resin material.

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