A general-purpose material identification and transport method and system for air spring assembly.

Abstract

This invention provides a universal material identification and transportation method and system for air spring assembly. The universal material identification and transportation method for air spring assembly includes material gripping: based on a first pose, the robot is controlled to grip the material; material alignment: based on a second pose, the robot is controlled to grip the material again; material positioning: a third pose is recorded; and material placement: based on the first, second, and / or third poses, the robot is controlled to place one or two materials at a specific location. The universal material identification and transportation system for air spring assembly includes a robot, a carrier, a fixture library, an alignment station, a positioning station, and a host computer. The universal material identification and transportation method and system for air spring assembly provided by this invention solves the problem that existing automated production and assembly schemes and visual recognition schemes for air springs are not suitable for the universal material transportation needs in air spring assembly.

Description

Technical Field

[0001] This invention relates to the field of air springs, and more specifically to a universal material identification and transportation method and system for air spring assembly. Background Technology

[0002] With the development of railway passenger car technology, passengers have increasingly higher requirements for the smoothness and comfort of passenger cars. Air spring vibration damping technology has made significant progress in China, and most OEMs adopt air spring devices in their vehicle designs. An air spring is basically composed of an auxiliary spring, an air bladder, a retaining ring, and a cover plate. In the production process, the air bladder and retaining ring are usually assembled first, then the air bladder and auxiliary spring are assembled, and finally the cover plate is installed. With advancements in production technology, traditional manual production processes have been largely phased out, and semi-automatic or fully automatic assembly equipment is now widely used for air spring assembly. A search reveals existing Chinese invention patents, including application number "202311596853.1" entitled "Air Spring Assembly System and Air Spring Assembly Control Method" by CRRC Qingdao Sifang Vehicle Research Institute Co., Ltd., and application number "202310612518.X" entitled "Automatic Feeding Device and Method for Integrated Air Spring Molding" by Qingdao Keyuyuan Intelligent Technology Co., Ltd., which disclose technical solutions for the automated production and assembly of air springs.

[0003] In addition, there are Chinese invention patents with application number “201810063064.4”, entitled “A visual recognition and positioning method for robot intelligent grasping applications”, with the applicant being “Harbin Institute of Technology Robotics (Hefei) International Innovation Research Institute”; and Chinese invention patents with application number “202010298389.8”, entitled “A disordered stacked workpiece grasping system and interaction method based on 3D vision”, with the applicant being “Beijing Migration Technology Co., Ltd.”, which disclose technical solutions for robot grasping and transporting materials based on visual information processing.

[0004] In existing automated production and assembly solutions for air springs, most are designed for assembling single-type air springs, with parts arranged neatly using dedicated carriers, and the versatility of the transport system is not a high priority. Existing robotic grasping and transport solutions are mostly relatively low-level designs, requiring optimization and modification for specific air spring production systems. Therefore, this application provides a universal material identification and transport method and system for air spring assembly. Summary of the Invention

[0005] To address the problem that existing automated production and assembly schemes and visual recognition schemes for air springs are insufficient to fully meet the universal material handling requirements in air spring assembly, this invention provides a universal material identification and handling method and system for air spring assembly that solves the above-mentioned problems.

[0006] A general material identification and transportation method for air spring assembly, comprising: Step 1: Material handling, specifically including: Step 1.1: The robot includes a first vision mechanism. The robot is equipped with an appropriate gripper and the first vision mechanism is moved to the top of the carrier to take pictures of the material. Step 1.2: The host computer analyzes the captured image and records the first pose; Step 1.3: Based on the first pose, control the robot to perform the grasping action; Step 2: Material calibration, specifically including: Step 2.1: The robot transports the grabbed material to the calibration station; Step 2.2: The calibration station includes a second vision mechanism, which takes pictures while calibrating the material, and the host computer records the second pose after calibration is completed; Step 2.3: Based on the second pose, control the robot to perform the grasping action; Step 3: Material positioning, specifically including: Step 3.1: The robot moves the grasped material closer to the positioning station; Step 3.2: The positioning station includes a third vision mechanism to capture images of the material. The host computer analyzes the captured images and records the third pose. Step 4: Material placement, specifically including Step 4.1: The host computer controls the robot to place the material individually at a specific location based on the first, second, or third pose. Step 4.2: The host computer controls the robot to place the two materials according to specific rules based on the first and second poses; or based on the second and third poses; or based on the first and third poses.

[0007] In a preferred embodiment of the universal material identification and transportation method for air spring assembly provided by the present invention, step 2 is used to calibrate the airbag or airbag buckle assembly: A calibration label is placed on the outer wall of the airbag. During the calibration process, the second vision mechanism tracks and records the position of the calibration label to achieve calibration.

[0008] Step 3 is used to position the auxiliary spring or auxiliary spring airbag assembly: The third vision mechanism captures images of the pin and pin hole positions at the bottom of the auxiliary spring, and the host computer analyzes the captured images and records the third pose.

[0009] In a preferred embodiment of the universal material identification and transportation method for air spring assembly provided by the present invention, step 4.1 includes: Based on the first pose, control the robot to place the buckle in a specific position; Based on the first pose, control the robot to place the cover plate in a specific position; Based on the second pose, the robot is controlled to place the airbag in a specific position; Based on the second pose, the robot is controlled to place the airbag buckle assembly in a specific position; Based on the third pose, the robot is controlled to place the auxiliary spring in a specific position; Based on the third pose, the robot is controlled to place the auxiliary spring airbag assembly in a specific position.

[0010] Step 4.2 includes: Based on the first and second poses, the buckle and airbag are placed together according to specific rules to assemble an airbag buckle assembly. Based on the second and third poses, the airbag buckle assembly and the auxiliary spring are placed together according to specific rules to assemble the auxiliary spring airbag assembly. Based on the first and third positions, the cover plate and auxiliary spring airbag assembly are placed together according to specific rules to assemble the finished air spring.

[0011] In a preferred embodiment of the universal material identification and transportation method for air spring assembly provided by the present invention, the analysis method in step 1.2 includes: Step 1.2.1: Obtain the perspective scan depth data of the material; Step 1.2.2: Orthogonally project the perspective scan depth data into a point cloud to obtain its orthogonal projection depth map; Step 1.2.3: Input the depth map into the material target detection algorithm to detect the overall material outline and the feature areas that need to be aligned when the robot grasps it; Step 1.2.4: Perform feature point calculation on the detected material feature areas and overall outline to obtain each feature point of the material; Step 1.2.5: Combine the various feature points of the material with the material gripping process to calculate the position of the material gripping point and calculate the normal vector of that point; Step 1.2.6: Based on the normal vector and the positions of some feature points, calculate the robot's position and Euler angle pose during grasping using the optimization principle of the minimum path of the robot's end effector. This is the first pose.

[0012] In a preferred embodiment of the universal material identification and transportation method for air spring assembly provided by the present invention, before the first vision mechanism takes a picture of the material, the method further includes: the first vision mechanism performing vision mechanism calibration to correspond the image coordinate system with the world coordinate system.

[0013] A general-purpose material identification and transportation system for air spring assembly includes a robot, and a carrier, a fixture library, a calibration station, a positioning station, and a host computer arranged around the robot. The robot selects different fixtures from the fixture library and, under the control of the host computer, picks up different materials from the carrier and places them in the next process, or places them in the next process after processing at the calibration station or the positioning station.

[0014] In a preferred embodiment of the universal material identification and transportation system for air spring assembly provided by the present invention, the carrier is adapted to the transportation of various materials, including multiple carriers respectively used to place auxiliary springs, airbags, buckles, cover plates, airbag buckle assemblies and auxiliary spring airbag assemblies.

[0015] In a preferred embodiment of the universal material identification and transport system for air spring assembly provided by the present invention, a plurality of the aforementioned fixture libraries are included, respectively for placing fixtures for auxiliary springs, airbags, buckles, cover plates, airbag buckle assemblies and auxiliary spring airbag assemblies.

[0016] Compared to existing technologies, the universal material identification and transportation system for air spring assembly provided by this invention adopts a universal design, including a carrier applicable to a variety of air spring parts, and a robot applicable to a variety of air spring parts by changing the clamps.

[0017] Compared with existing technologies, the universal material identification and transportation method for air spring assembly provided by this invention has the following advantages: 1. The solution provided by the present invention uses a first vision mechanism set at the end of the robot to photograph the material before it is gripped and to identify and analyze the material's position and posture. This can adapt to situations where the material is stacked crookedly in the carrier and ensure accurate gripping.

[0018] 2. The solution provided by this invention identifies the positional data of bolt holes and other components in the material during visual analysis when clamping the material, and aligns the material immediately when placing it. No further alignment correction is required during the assembly process, which improves assembly efficiency.

[0019] 3. The solution provided by this invention organically combines the production processes of air springs, such as transportation, assembly, and testing, to ensure rapid product changeover and flexible production. Attached Figure Description

[0020] Figure 1This is a schematic diagram of a general-purpose material identification and transportation system used for air spring assembly; Figure 2 This is a flowchart of a general material identification and transportation method for air spring assembly. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] Please see Figure 1 This is a structural schematic diagram of a universal material identification and transportation system for air spring assembly provided by the present invention.

[0023] A general-purpose material identification and transportation system for air spring assembly includes a robot 1, a carrier 2, a fixture library 3, a calibration station 4, a positioning station 5, and a host computer 6. In implementation, it should naturally also include loading and unloading equipment, assembly equipment 7, etc., which will not be elaborated upon here.

[0024] Robot 1 is an existing device, and to extend its travel, it is mounted on a linear motion platform. A gripper mounting interface and a first vision mechanism are installed at the end of Robot 1.

[0025] The carrier 2 is a general-purpose carrier, including a platform 21 and four radially arranged support rails 22 on the top surface of the platform 21. Support columns 23 are movably mounted on the support rails 22. By changing the position of the support columns 23, it can accommodate various materials of different sizes. Only two carriers 2 are shown in the attached figure. In implementation, the appropriate number of carriers 2 should be selected according to the requirements.

[0026] Fixture library 3 is a stand with one or two fixtures placed on its top surface. Only two fixture libraries 3 are shown in the attached diagram. During implementation, select an appropriate number of fixture libraries according to requirements, and choose the appropriate quantity and type of fixtures from among buckle fixtures, airbag fixtures, auxiliary spring fixtures, cover plate fixtures, airbag buckle assembly fixtures, auxiliary spring airbag assembly fixtures, etc.

[0027] The calibration station 4 includes a base 41, a rotating platform 42, sensors 43, and a second vision mechanism 44. The rotating platform 42, which rotates in a horizontal plane, is mounted on top of the base 41. A pair of sensors 43 are mounted opposite each other at two diagonal positions on the top of the platform to detect whether an object is placed on it. The second vision mechanism 44 is mounted near the base 41 via a single column, with its lens facing the rotating platform 42.

[0028] The positioning device 5 includes a third vision mechanism with its lens pointing vertically upwards.

[0029] The host computer 6 is existing equipment. The assembly equipment 7 is existing equipment.

[0030] Please see Figure 2 This is a flowchart of a universal material identification and transportation method for air spring assembly provided by the present invention.

[0031] A general material identification and transportation method for air spring assembly, comprising: Step 1: The robot calibrates the first vision mechanism before gripping.

[0032] The first vision unit takes pictures of the chessboard calibration board, collects the corresponding calibration images, and then calculates the affine matrix of the calibration target from the image coordinate system to the world coordinate system according to Zhang Zhengyou's calibration algorithm, thus mapping the image coordinate system to the world coordinate system.

[0033] Step 2: Identify the carrier using the buckle.

[0034] Step 2.1: The robot selects the buckle gripper according to the taught path and moves the first vision mechanism to the top of the carrier carrying the buckle to take a picture of the buckle.

[0035] Step 2.2: Obtain perspective scan depth data of the buckle; The perspective scan depth data is processed into a point cloud and orthogonally projected to obtain its orthogonal projection depth map. The depth map is fed into the material target detection algorithm, which detects the overall material outline and the feature areas that need to be aligned when the robot grasps it. The detected material feature regions and overall contours are processed by filtering, calculating the circumcenter, and other calculations to obtain the various feature points of the material. By combining the various feature points of the material with the material gripping process, the position of the material gripping point is obtained, and the normal vector of that point is calculated. Based on the normal vector and the positions of some feature points, the robot's position and Euler angles during grasping are calculated using the optimization principle of minimum path for the robot's end effector, and denoted as the first pose of the buckle. The first pose of the buckle includes the pose of the buckle bolt holes.

[0036] Step 2.3: Robot 1 grips the buckle based on its first pose and places it in the designated position on assembly equipment 7 based on the taught path.

[0037] Step 3: Airbag identification of the vehicle.

[0038] Step 3.1: The robot selects the airbag gripper according to the taught path and moves the first vision mechanism to the top of the vehicle carrying the airbag to take a picture of the airbag.

[0039] Step 3.2: Obtain the fluoroscopic depth data of the airbag; Following the same processing procedure, the position and Euler angle pose of robot 1 when grasping are obtained, and recorded as the first pose of the airbag.

[0040] Step 3.3: Robot 1 grasps the airbag based on its first pose and places it onto the rotating platform 42 of the calibration device 4 based on the taught path.

[0041] Step 3.4: Pre-set identification labels on the surface of the airbag.

[0042] When sensor 43 detects an airbag placed on rotating platform 42, it controls rotating platform 42 to start and rotate the airbag. Second vision mechanism 44 tracks and identifies the tag, and controls rotating platform 42 to stop when it rotates to the correct angle.

[0043] The calibrated airbag is in a fixed position, which is denoted as the second airbag position.

[0044] Step 3.5: Robot 1 grips the airbag based on its second pose. Following the taught path, it places the airbag at the designated position in assembly equipment 7. Simultaneously, based on the first pose of the buckle and the second pose of the airbag, it determines the alignment requirements of the bolt holes between the buckle and the airbag. Subsequently, assembly equipment 7 completes the assembly, forming the airbag buckle assembly.

[0045] Step 4: Auxiliary spring identifies the carrier.

[0046] Step 4.1: The robot selects the auxiliary spring gripper according to the teaching path and moves the first vision mechanism to the top of the carrier carrying the auxiliary spring to take a picture of the auxiliary spring.

[0047] Step 4.2: Obtain the perspective scan depth data of the auxiliary spring; Following the same processing procedure, the position and Euler angle orientation of robot 1 when grasping are obtained, and recorded as the first orientation of the auxiliary spring.

[0048] Step 4.3: Robot 1 grasps the auxiliary spring based on its first pose and places it above the positioning device 5 according to the taught path.

[0049] Step 4.4: The third vision mechanism in the positioning device 5 identifies the pin hole and pin shaft position at the bottom of the auxiliary spring and records them as the third pose of the auxiliary spring.

[0050] Step 4.5: Based on the third pose of the auxiliary spring, robot 1 places the auxiliary spring at the designated position in assembly equipment 7 along the taught path. Based on the second pose of the airbag and the third pose of the auxiliary spring, the various assembly requirements between the airbag buckle assembly and the auxiliary spring are determined. Subsequently, assembly equipment 7 completes the assembly to form the auxiliary spring airbag assembly.

[0051] Step 5: The auxiliary spring airbag assembly identifies the vehicle.

[0052] Step 5.1: The auxiliary spring airbag assembly is in a fixed pose; the robot selects the auxiliary spring airbag assembly gripper according to the taught path and completes the gripping of the auxiliary spring airbag assembly; based on the taught path, the auxiliary spring airbag assembly is placed on the same or another positioning device 5; Step 5.2: The third vision mechanism in the positioning device 5 identifies the pin hole and pin shaft position at the bottom of the auxiliary spring and records them as the third pose of the auxiliary spring airbag assembly.

[0053] Step 5.3: Based on the third pose of the auxiliary spring airbag assembly, robot 1 places the auxiliary spring airbag assembly at the designated position in the second assembly equipment 8 along the taught path.

[0054] Step 6: Cover plate identifies the vehicle.

[0055] Step 6.1 The robot selects the cover plate fixture according to the teaching path and moves the first vision mechanism to the top of the carrier carrying the cover plate to take a picture of the cover plate.

[0056] Step 6.2: Obtain the perspective scan depth data of the cover plate; Following the same processing procedure, the position and Euler angle orientation of robot 1 during grasping are obtained and recorded as the first orientation of the cover plate. The first orientation of the cover plate includes the orientation of the cover plate bolt holes.

[0057] Step 6.3: Robot 1 grips the cover plate based on its first pose and places it in the designated position on the assembly equipment 7 based on the taught path.

[0058] Simultaneously, based on the first position of the cover plate and the third position of the auxiliary spring airbag assembly, the alignment requirements of the bolt holes between the cover plate and the auxiliary spring airbag assembly are determined. Subsequently, the second assembly equipment 8 completes the assembly to form the finished air spring.

[0059] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A universal material identification and carrying method for air spring assembly, characterized in that, include: Step 1: Material handling, specifically including: Step 1.1: The robot includes a first vision mechanism. The robot is equipped with an appropriate gripper and the first vision mechanism is moved to the top of the carrier to take pictures of the material. Step 1.2: The host computer analyzes the captured image and records the first pose; The analytical methods in step 1.2 include: Step 1.2.1: Obtain the perspective scan depth data of the material; Step 1.2.2: Orthogonally project the perspective scan depth data into a point cloud to obtain its orthogonal projection depth map; Step 1.2.3: Input the depth map into the material target detection algorithm to detect the overall material outline and the feature areas that need to be aligned when the robot grasps it; Step 1.2.4: Perform feature point calculation on the detected material feature areas and overall outline to obtain each feature point of the material; Step 1.2.5: Combine the various feature points of the material with the material gripping process to calculate the position of the material gripping point and calculate the normal vector of that point; Step 1.2.6: Based on the normal vector and the positions of some feature points, calculate the robot's position and Euler angle pose during grasping using the optimization principle of the minimum path of the robot's end effector. This is the first pose. Step 1.3: Based on the first pose, control the robot to perform the grasping action; Step 2: Material calibration, specifically including: Step 2.1: The robot transports the grabbed material to the calibration station; Step 2.2: The calibration station includes a second vision mechanism, which takes pictures while calibrating the material, and the host computer records the second pose after calibration is completed; Step 2.3: Based on the second pose, control the robot to perform the grasping action; Step 2 is used to calibrate the airbag or airbag buckle assembly: a calibration label is set on the outer wall of the airbag. During the calibration process, the second vision mechanism tracks and records the position of the calibration label to achieve calibration. Step 3: Material positioning, specifically including: Step 3.1: The robot moves the grasped material closer to the positioning station; Step 3.2: The positioning station includes a third vision mechanism to capture images of the material. The host computer analyzes the captured images and records the third pose. Step 3 is used to position the auxiliary spring or auxiliary spring airbag assembly: the third vision mechanism takes pictures of the pin and pin hole positions at the bottom of the auxiliary spring, and the host computer analyzes the captured images and records the third pose; Step 4: Material placement, specifically including: Step 4.1: The host computer controls the robot to place the material individually at a specific location based on the first, second, or third pose. Step 4.2: The host computer controls the robot to place the two materials according to specific rules based on the first and second poses; or based on the second and third poses; or based on the first and third poses.

2. The universal material identification and transportation method for air spring assembly according to claim 1, characterized in that, Step 4.1 includes: Based on the first pose, control the robot to place the buckle in a specific position; Based on the first pose, control the robot to place the cover plate in a specific position; Based on the second pose, the robot is controlled to place the airbag in a specific position; Based on the second pose, the robot is controlled to place the airbag buckle assembly in a specific position; Based on the third pose, the robot is controlled to place the auxiliary spring in a specific position; Based on the third pose, the robot is controlled to place the auxiliary spring airbag assembly in a specific position.

3. The universal material identification and transportation method for air spring assembly according to claim 2, characterized in that, Step 4.2 includes: Based on the first and second poses, the buckle and airbag are placed together according to specific rules to assemble an airbag buckle assembly. Based on the second and third poses, the airbag buckle assembly and the auxiliary spring are placed together according to specific rules to assemble the auxiliary spring airbag assembly. Based on the first and third positions, the cover plate and auxiliary spring airbag assembly are placed together according to specific rules to assemble the finished air spring.

4. The universal material identification and transportation method for air spring assembly according to claim 1, characterized in that, Before the first vision mechanism takes a picture of the material, the method further includes: the first vision mechanism performing vision mechanism calibration to align the image coordinate system with the world coordinate system.

5. An identification and transportation system based on the universal material identification and transportation method for air spring assembly according to any one of claims 1 to 4, characterized in that: It includes a robot, as well as a carrier, a fixture library, a calibration station, a positioning station, and a host computer arranged around the robot. The robot selects different fixtures from the fixture library and, under the control of the host computer, picks up different materials from the carrier and places them in the next process, or places them in the next process after being processed by the calibration station or the positioning station.

6. The identification and transportation system according to claim 5, characterized in that, The carrier is adapted to transport various materials and includes multiple carriers for placing auxiliary springs, airbags, buckles, cover plates, airbag buckle assemblies and auxiliary spring airbag assemblies respectively.

7. The identification and transportation system according to claim 5, characterized in that, It includes multiple clamp libraries for placing clamps for auxiliary springs, airbags, buckles, cover plates, airbag buckle assemblies, and auxiliary spring airbag assemblies.

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