A feeding and discharging method and a composite robot

Abstract

A loading / unloading method and a composite robot are disclosed. The composite robot includes a mobile chassis and a superstructure. The superstructure has a six-degree-of-freedom (DOF) adjustable platform, the lower plane of which is fixedly connected to the mobile chassis. The upper plane of the six-DOF adjustable platform is equipped with a docking mechanism and a loading / unloading device. The six-DOF adjustable platform is a Stewart-structured parallel robot. The docking mechanism includes a primary positioning camera for primary positioning and an electric push rod and a multi-dimensional feedback sensor for secondary positioning. The core of the multi-dimensional feedback sensor is a six-dimensional force sensor or a six-dimensional micro-displacement sensor. The loading / unloading device is a multi-axis robotic arm. The superstructure has a controller that uniformly controls the six-DOF adjustable platform, the docking mechanism, and the loading / unloading device. After primary and secondary positioning alignment, the controller controls the multi-axis robotic arm to perform loading / unloading according to a taught method. This achieves a loading / unloading process and accuracy similar to a fixed robotic arm, and the end effector of the loading / unloading robotic arm does not need to carry a positioning camera, reducing the required workspace.

Description

Technical Field

[0001] This invention belongs to the field of robotics technology, specifically a material loading and unloading method and a composite robot. Background Technology

[0002] Material handling robots are automated devices that integrate mobile handling and precision operation, primarily used for the automated flow of materials in machine tools, production lines, and other similar environments. By combining a mobile chassis, robotic arm, and vision system, these robots enable autonomous material handling and transfer between different workstations, making them a key tool for improving efficiency in intelligent manufacturing.

[0003] Most current composite loading and unloading robots consist of an autonomous mobile chassis with a multi-axis robotic arm fixed to its end effector. The robotic arm's end effector is equipped with a positioning camera and loading / unloading fixtures. After the composite robot arrives at the loading / unloading station, it uses the positioning camera to photograph pre-installed positioning markers on the station and calculates the 6-dimensional pose of the markers in the camera's coordinate system. This eliminates inconsistencies in the stopping accuracy of the autonomous mobile chassis with each stop. Then, based on the coordinate transformation relationship and the coordinate difference between the pre-taught loading / unloading pose and the positioning marker pose, the robot calculates the 6-dimensional coordinates of the current loading / unloading pose in the multi-axis robotic arm's base coordinate system. Combined with the pre-taught path, the robot completes the loading or unloading operation.

[0004] This method can meet the accuracy requirements of general scenarios, but it cannot meet some higher accuracy requirements, or some scenarios have limited space, which does not allow multi-axis robotic arms carrying positioning cameras and loading / unloading fixtures to enter the operation.

[0005] This invention provides a novel composite loading and unloading robot structure and a novel loading and unloading method. It first eliminates the inconsistency in the stopping accuracy of the autonomous moving chassis through a 6-DOF platform, and then uses a multi-axis robotic arm for loading and unloading. This achieves a loading and unloading process and accuracy similar to a fixed robotic arm, and the end effector of the loading and unloading robotic arm does not require a positioning camera, reducing the required workspace. Summary of the Invention

[0006] This invention provides a material loading and unloading method and a composite robot.

[0007] A loading / unloading method, characterized by comprising one or more composite robots and one or more machine platforms; the composite robot includes a mobile chassis and a superstructure, the superstructure having a six-degree-of-freedom adjustable platform, the lower plane of the six-degree-of-freedom adjustable platform being fixedly connected to the mobile chassis, and the upper plane of the six-degree-of-freedom adjustable platform being equipped with a docking mechanism and a loading / unloading device; the superstructure has a superstructure controller, which uniformly controls the six-degree-of-freedom adjustable platform, the docking mechanism, and the loading / unloading device to realize the loading or unloading of materials by the composite robot onto the machine platform; each machine platform has a positioning mechanism for docking with the docking mechanism on the composite robot; the loading / unloading process includes three stages: Phase 1: A composite robot moves to the front of a machine under the control of a navigation system; Phase 2: The docking mechanism and the positioning mechanism on the machine are measured to obtain the six-dimensional pose difference between the docking mechanism and the positioning mechanism on the machine. The upper controller controls the six-degree-of-freedom adjustable platform to adjust in six degrees of freedom so that the docking mechanism and the positioning mechanism on the machine are aligned and the six-dimensional pose difference reaches a preset fixed value. Phase 3: The upper controller controls the loading and unloading device located on the upper plane of the six-degree-of-freedom adjustable platform to load or unload materials at designated positions on the machine platform.

[0008] To this end, the docking mechanism includes a primary positioning camera; the positioning mechanism on the machine includes a primary positioning marker; the primary positioning camera takes a picture of the primary positioning marker, calculates the pose difference between the primary positioning camera and the primary positioning marker, the upper-mounted controller controls the six-degree-of-freedom adjustable platform to adjust in six degrees of freedom, the primary positioning camera and the primary positioning marker are aligned, and the six-dimensional pose difference reaches a preset fixed value, thereby achieving primary positioning alignment.

[0009] Furthermore, the docking mechanism includes an electric push rod and a multi-dimensional feedback sensor; the positioning mechanism on the machine includes a secondary positioning head; after completing the first positioning alignment, the upper-mount controller controls the electric push rod to slowly extend towards the secondary positioning head of the machine. The contact process between the multi-dimensional feedback sensor and the secondary positioning head causes the multi-dimensional feedback sensor to generate an output signal. The upper-mount controller controls the six-degree-of-freedom adjustable platform to adjust in six degrees of freedom according to this output signal, so that the multi-dimensional feedback sensor and the secondary positioning head can precisely cooperate, thereby achieving secondary positioning alignment.

[0010] Optionally, the multidimensional feedback sensor includes a six-dimensional force sensor and a guide pin installed at the end of the electric push rod. The guide pin is a square bar with chamfers. The secondary positioning head on the machine platform is a square hole. The upper controller analyzes the force direction output by the six-dimensional force sensor and controls the six-degree-of-freedom adjustable platform to adjust in six degrees of freedom, so that the guide pin accurately enters the square hole, thereby achieving secondary positioning and alignment.

[0011] Optionally, the multidimensional feedback sensor is a six-dimensional micro-displacement sensor installed at the end of the electric push rod. The six-dimensional micro-displacement sensor includes a six-dimensional micro-displacement body, multiple radial micro-displacement sensors, and multiple axial micro-displacement sensors. The secondary positioning head on the machine is a square column. All micro-displacement sensors of the six-dimensional micro-displacement sensor are calibrated using a calibration fixture to obtain a reference value. The upper controller analyzes the difference between the displacement reading output by the six-dimensional micro-displacement sensor and the reference value, and controls the six-degree-of-freedom adjustable platform to adjust in six degrees of freedom, so that the six-dimensional micro-displacement sensor accurately fits the square column, thereby achieving secondary positioning alignment.

[0012] The loading and unloading device is a multi-axis robotic arm. After the docking mechanism located on the horizontal plane of the six-degree-of-freedom adjustable platform performs a first or second positioning alignment with the positioning mechanism on the machine, the multi-axis robotic arm completes the initial loading or unloading through teaching and records the corresponding end pose and arrival path. Subsequent loading or unloading is automatically completed based on the results of the initial teaching record.

[0013] Preferably, the six-degree-of-freedom adjustable platform is a Stewart-structured parallel robot.

[0014] The primary positioning identifier is a QR code with visual positioning function and ID information; the primary positioning camera obtains the six-dimensional information of the QR code in the camera coordinate system and the ID information contained in the QR code by taking pictures of the QR code and processing it with algorithms; each QR code serving as a primary positioning identifier on each machine has unique ID information.

[0015] A composite robot is characterized in that: the composite robot includes a mobile chassis and a superstructure, the superstructure having a six-degree-of-freedom adjustable platform, the lower plane of the six-degree-of-freedom adjustable platform being fixedly connected to the mobile chassis, and the upper plane of the six-degree-of-freedom adjustable platform being equipped with a docking mechanism and a loading / unloading device; the six-degree-of-freedom adjustable platform is a Stewart-structured parallel robot; the docking mechanism includes a primary positioning camera for primary positioning and an electric push rod and a multi-dimensional feedback sensor for secondary positioning; the multi-dimensional feedback sensor includes a six-dimensional force sensor and a guide pin installed at the end of the electric push rod, the guide pin being a square bar with chamfers; the loading / unloading device is a multi-axis robotic arm; the superstructure has a superstructure controller, which uniformly controls the six-degree-of-freedom adjustable platform, the docking mechanism, and the loading / unloading device, realizing loading or unloading according to the aforementioned feasible loading / unloading method.

[0016] Another type of composite robot is characterized in that: the composite robot includes a mobile chassis and a superstructure, the superstructure having a six-degree-of-freedom adjustable platform, the lower plane of the six-degree-of-freedom adjustable platform being fixedly connected to the mobile chassis, and the upper plane of the six-degree-of-freedom adjustable platform being equipped with a docking mechanism and a loading / unloading device; the six-degree-of-freedom adjustable platform is a Stewart structure parallel robot; the docking mechanism includes a primary positioning camera for primary positioning and an electric push rod and a multi-dimensional feedback sensor for secondary positioning; the multi-dimensional feedback sensor is a six-dimensional micro-displacement sensor installed at the end of the electric push rod, the six-dimensional micro-displacement sensor including one six-dimensional micro-displacement body, four radial micro-displacement sensors, and four axial micro-displacement sensors; the loading / unloading device is a multi-axis robotic arm; the superstructure has a superstructure controller, which uniformly controls the six-degree-of-freedom adjustable platform, the docking mechanism, and the loading / unloading device, realizing loading or unloading according to the above-mentioned feasible unloading method.

[0017] The beneficial effects of this application are as follows: By first eliminating the inconsistency in the stopping accuracy of the autonomous moving chassis with a six-degree-of-freedom platform, and then using a multi-axis robotic arm for loading and unloading, a process and accuracy similar to that of a fixed robotic arm for loading and unloading are achieved. The end effector of the loading and unloading robotic arm does not need to carry a positioning camera, reducing the required workspace.

[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0019] The present application will be further described below with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic diagram of the loading and unloading system; Figure 2This is a schematic diagram of a Stewart-structured six-DOF platform; Figure 3 This is a schematic diagram of a four-axis loading and unloading robotic arm; Figure 4 This is a diagram of the AprilTag QR code; Figure 5 This is a schematic diagram of the docking system composition in Implementation Example 1; Figure 6 This is a schematic diagram of the docking system composition in Embodiment 2; Figure 7 This is an exploded diagram of a six-dimensional micro-displacement sensor assembly. Figure 8 This is a picture of a pen-type capacitive displacement sensor; Figure 9 This is a schematic diagram of the calibration state profile of a six-dimensional micro-displacement sensor; Explanation of reference numerals in the attached figures: 100. Mobile robot chassis; 200. Stewart six-DOF platform: 201. Stewart lower plane; 202. Stewart push rods, 6 in total; 203. Stewart upper plane; 204. Upper controller; 300. Four-axis loading and unloading robotic arm; 301. Lifting column; 302. Three-axis movable arm; 303. Gripper; 400. Docking mechanism; 401. QR code camera; 402. Electric push rod; 403. Six-dimensional force sensor; 404. Guide pin; 40. Six-dimensional micro-displacement sensor; 41. Six-dimensional micro-displacement body; 42. Radial micro-displacement sensor (4 in total); 43. Axial micro-displacement sensor (4 in total); 500. Machine base; 501. Positioning QR code; 502. Secondary positioning square hole; 503. Secondary positioning square post; 504. Calibration positioning pin, a total of 4; 600. Materials to be processed, several in total. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] Figure 1This is a schematic diagram of the loading and unloading system, which shows a composite robot and a machine platform 500. The composite robot includes a robot chassis 100, a Stewart six-DOF platform 200, a four-axis loading and unloading robotic arm 300, and a docking mechanism 400. Figure 1 Several materials 600 to be processed were also displayed, which may be temporarily stored on the composite robot or on the machine platform. In the composite robot, apart from the mobile robot chassis, the other parts are conventionally referred to as the superstructure, which is fixed to the mobile robot chassis. The lower plane of the Stewart-structured six-DOF platform 200 is fixedly connected to the robot chassis 100, and the upper plane of the Stewart-structured six-DOF platform 200 is equipped with a docking mechanism 400 and a loading / unloading device 300; the machine platform 500 has a positioning mechanism that docks with the docking mechanism 400 on the composite robot.

[0023] The six-degree-of-freedom adjustable platform can be implemented in different structures, such as Stewart parallel robots and 6-axis cascaded slides. This invention prioritizes the use of Stewart structure parallel robots with strong torsional resistance. For the relevant principles and design calculations of Stewart structure robots, please refer to relevant tutorials and public information. Figure 2 This is a schematic diagram of a six-DOF platform with a Stewart structure. The Stewart-structure six-DOF platform 200 includes a Stewart lower plane 201, six Stewart push rods 202, and a Stewart upper plane 203. The Stewart lower plane 201 is fixedly connected to the mobile robot chassis 100. The Stewart push rods 202 are generally mounted with spherical hinges at both ends, or one end is a universal hinge (also known as a Hooke hinge) and the other end is a spherical hinge, so that the Stewart upper plane 203 can be adjusted in six degrees of freedom. The upper controller 204 can be installed on the Stewart lower plane 201 or the Stewart upper plane 203, and it uniformly controls the Stewart-structure six-DOF platform 200, the docking mechanism 400, and the loading and unloading device 300 to realize the loading and unloading of the composite robot on the machine platform 500. The normal performance of laser SLAM navigation to point on the mobile robot chassis is + / -10mm and + / -1° horizontally. The design specifications for the motion range of the Stewart structure six-DOF platform 200 in this invention are + / -50mm horizontally in the X direction, + / -50mm horizontally in the Y direction, and + / -20mm vertically in the Z direction, with three-axis rotation Rx=Ry=Rz=+ / -10°, leaving sufficient margin.

[0024] Figure 3This is a four-axis loading / unloading robotic arm. The four-axis loading / unloading robotic arm 300 includes a lifting column 301, a three-axis movable arm 302, and a gripper 303. The three-axis movable arm 302 has three axes and can move up and down along the lifting column 301, possessing four degrees of freedom (three displacements and one rotation). It can perform most loading / unloading actions, such as picking, placing, pushing, and pulling. For situations requiring two additional rotation angles, and where the rotation angles are small, additional tools can be used... Figure 2 The Stewart-structured six-DOF platform 200 can perform small-angle rotations. For other scenarios requiring more degrees of freedom, other multi-axis robotic arms or other types of mechanisms can be used, which will not be listed here.

[0025] This invention employs QR code positioning technology for single-stage positioning. QR codes can take various forms, such as QR codes, ArUco codes, and AprilTag codes, all of which have abundant publicly available information. This invention chooses AprilTag as an example. AprilTag is a visual reference system applicable to various tasks, including augmented reality, robotics, and camera calibration. AprilTag detection can calculate the precise 3D position, orientation, and ID of the calibration board relative to the camera. Different IDs are assigned to different docking stations. After recognizing the pattern, the camera directly reads the numerical ID to distinguish the target station, while simultaneously calculating the 6D pose of the AprilTag QR code. Figure 4 The AprilTag QR code is used as a one-time location QR code 501.

[0026] Close-range QR code positioning can achieve high accuracy within 1mm, which is sufficient for some scenarios. For scenarios where single-stage positioning accuracy is insufficient, this invention implements secondary positioning based on the initial positioning. This invention employs contact positioning for secondary positioning and provides two embodiments, corresponding to both the docking mechanism of the composite robot and the secondary positioning head on the machine side.

[0027] Example 1 of secondary positioning is as follows: Figure 5 This is a schematic diagram of the docking system composition in Embodiment 1. The docking mechanism in Embodiment 1 includes a QR code camera 401, an electric push rod 402, a six-dimensional force sensor 403, and a guide pin 404. For ease of explanation, Figure 5The positioning mechanism on the fixed platform 500 is also shown, which includes a primary positioning QR code 501 and a secondary positioning square hole 502. An electric push rod 402, carrying a six-dimensional force sensor 403 and a guide pin 404, gradually approaches the square hole 502. The guide pin 404 has a chamfer, and the contact generated during its entry into the square hole 502 causes an additional six-dimensional force output from the six-dimensional force sensor 403. The upper controller 204 analyzes the direction and magnitude of the force and controls the fine-tuning of the six-degree-of-freedom platform 200 to ensure the guide pin 404 accurately enters the square hole 502, thus achieving secondary positioning alignment.

[0028] The loading and unloading process of the docking system in Implementation Example 1 includes three stages: Phase 1: A composite robot moves to the front of a machine under the control of the navigation system.

[0029] Phase Two: Primary and Secondary Positioning. During primary positioning, the QR code camera 401 of the docking mechanism photographs the primary positioning QR code 501 on the machine platform, calculates the pose difference between the camera and the QR code, and the upper-mount controller 204 controls the Stewart structure six-DOF platform 200 to perform fine adjustments in six degrees of freedom, aligning the camera with the QR code until the six-dimensional pose difference reaches a preset fixed value. During secondary positioning, the electric push rod 402, carrying the six-dimensional force sensor 403 and guide pin 404, gradually approaches the square hole 502. The guide pin 404 has a chamfer; the contact generated during its entry into the square hole 502 causes an additional six-dimensional force output from the six-dimensional force sensor 403. The upper-mount controller 204 analyzes the direction and magnitude of the force and controls the fine adjustments of the Stewart structure six-DOF platform 200 to ensure the guide pin 404 accurately enters the square hole 502, thus achieving secondary positioning alignment.

[0030] Phase 3: The upper controller 204 controls the four-axis loading / unloading robotic arm 300 to load or unload materials at designated locations on the machine. Specifically, the four-axis robotic arm completes the initial loading or unloading through a teaching method and records the corresponding end-effector pose and arrival path. Subsequent loading or unloading is completed automatically based on the results of the initial teaching recording.

[0031] The second embodiment of secondary positioning is as follows: Figure 6 This is a schematic diagram of the docking system composition in Embodiment 2, including a QR code camera 401, an electric push rod 402, and a six-dimensional micro-displacement sensor 40. For ease of explanation, Figure 6 The positioning mechanism on the fixed machine 500 is also shown, which includes a primary positioning QR code 501 and a secondary positioning square column 503. Figure 7 This is an exploded view of the composition of the six-dimensional micro-displacement sensor 40, which includes a six-dimensional micro-displacement body 41, radial micro-displacement sensors 42 (4 in total), and axial micro-displacement sensors 43 (4 in total). Figure 8The image shows a physical diagram of a radial / axial micro-displacement sensor. One end of the sensor is a capacitive micro-displacement test head with a spring-loaded function, which can form elastic contact with the square post 503. The other end is connected to a dedicated signal processing circuit and transmits the signal to the upper-mounted controller 204. Theoretically, eight micro-displacement sensors are not needed to measure six-dimensional deviations; six with a reasonable arrangement would suffice. This invention uses eight for symmetrical installation, ease of fabrication, and convenient subsequent calibration and calculation.

[0032] To calibrate the six-dimensional displacement sensor and obtain reference values ​​for eight micro-displacement sensors, a calibration fixture was specifically designed. This calibration fixture includes... Figure 6 The system includes a primary positioning QR code 501, a secondary positioning square post 503, and four calibration positioning pins 504. During calibration, the calibration fixture precisely engages with the six-dimensional micro-displacement sensor 40 mounted on the side of the composite robot via the four calibration positioning pins. At this time, the secondary positioning square post 503 assigns the readings of the eight micro-displacement sensors as the reference value. Figure 9 This is a schematic diagram of the calibration state of a six-dimensional displacement sensor, including a secondary positioning square column 503 and four calibration positioning pins 504 located on the calibration fixture, a six-dimensional micro-displacement body 41, four radial micro-displacement sensors 42, and four axial micro-displacement sensors 43 located on the side of the composite robot, and four positioning holes on the six-dimensional micro-displacement body 41 precisely aligned with the four calibration positioning pins 504. The four calibration positioning pins are only needed during calibration; therefore, the positioning mechanism on the machine does not require the installation of four calibration positioning pins. The calibration of the six-dimensional displacement sensor is completed in advance before loading and unloading, and the reference values ​​are recorded.

[0033] Compared to calibration, during normal loading and unloading, a predetermined gap of several mm is maintained axially instead of a precise fit. There will be no rigid contact during the entire loading and unloading process. Only the 8 micro-displacement sensors will have elastic contact with the square column 503 for secondary positioning. Moreover, the displacement difference between the displacement sensor and the reference value can be obtained directly by subtraction. The upper controller 204 directly adjusts the Stewart structure six-degree-of-freedom platform 200 according to the displacement difference to achieve secondary positioning and alignment.

[0034] The loading and unloading process of the docking system in Embodiment 2 includes three stages: Phase 1: A composite robot moves to the front of a machine under the control of the navigation system.

[0035] Phase Two: Primary and Secondary Positioning. During primary positioning, the QR code camera 401 of the docking mechanism photographs the primary positioning QR code 501 on the machine platform, calculates the pose difference between the camera and the QR code, and the upper-mount controller 204 controls the Stewart structure six-DOF platform 200 to adjust in six degrees of freedom, aligning the camera with the QR code until the six-dimensional pose difference reaches a preset fixed value. During secondary positioning, the electric push rod 402, carrying the six-dimensional micro-displacement sensor 40, gradually approaches the secondary positioning square post 503. The elastic contact generated during this process causes displacement outputs from the eight micro-displacement sensors. The upper-mount controller 204 directly subtracts the displacement difference from the reference value and directly controls the Stewart structure six-DOF platform 200 to fine-tune in six degrees of freedom based on this displacement difference, ensuring that the six-dimensional micro-displacement sensor precisely fits onto the square post 503, thus achieving secondary positioning alignment.

[0036] Phase 3: The upper controller 204 controls the four-axis loading / unloading robotic arm 300 to load or unload materials at designated locations on the machine. Specifically, the four-axis robotic arm completes the initial loading or unloading through a teaching method and records the corresponding end-effector pose and arrival path. Subsequent loading or unloading is completed automatically based on the results of the initial teaching recording.

[0037] Understandably, depending on the different actuators on the six-degree-of-freedom adjustable platform, the composite robot of this application can perform a variety of functions. For example, when the actuator includes a robotic arm, the composite robot can be a loading and unloading robot, a gripping robot, etc.; when the actuator includes an image acquisition device, the composite robot can be an inspection robot, etc.

[0038] The foregoing disclosure provides many different implementations or examples for implementing the loading / unloading method and composite robot of this application. To simplify the disclosure, the components and arrangements of specific examples are described above. Of course, these are merely examples and are not intended to limit the scope of this application.

Claims

1. A method for loading and unloading materials, characterized in that, The system includes one or more composite robots and one or more machine stations. The composite robot comprises a mobile chassis and a superstructure. The superstructure has a six-degree-of-freedom adjustable platform, the lower surface of which is fixedly connected to the mobile chassis. The upper surface of the six-degree-of-freedom adjustable platform is equipped with a docking mechanism and a loading / unloading device. The superstructure has a controller that centrally controls the six-degree-of-freedom adjustable platform, the docking mechanism, and the loading / unloading device, enabling the composite robot to load or unload materials onto the machine station. Each machine station has a positioning mechanism that docks with the docking mechanism on the composite robot. The loading / unloading process includes three stages: Phase 1: A composite robot moves to the front of a machine station under the control of a navigation system; Phase 2: The docking mechanism and the positioning mechanism on the machine are measured to obtain the six-dimensional pose difference between the docking mechanism and the positioning mechanism on the machine. The upper controller controls the six-degree-of-freedom adjustable platform to adjust in six degrees of freedom so that the docking mechanism and the positioning mechanism on the machine are aligned and the six-dimensional pose difference reaches a preset fixed value. Phase 3: The upper controller controls the loading and unloading device located on the upper plane of the six-degree-of-freedom adjustable platform to load or unload materials at designated positions on the machine platform.

2. The feeding and discharging method according to claim 1, characterized in that: The docking mechanism includes a primary positioning camera; the positioning mechanism on the machine includes a primary positioning marker; the primary positioning camera takes a picture of the primary positioning marker, calculates the pose difference between the primary positioning camera and the primary positioning marker, the upper-mounted controller controls the six-degree-of-freedom adjustable platform to adjust in six degrees of freedom, the primary positioning camera and the primary positioning marker are aligned, and the six-dimensional pose difference reaches a preset fixed value, thereby achieving primary positioning alignment.

3. The feeding and discharging method according to claim 2, characterized in that: The docking mechanism includes an electric push rod and a multi-dimensional feedback sensor; the positioning mechanism on the machine includes a secondary positioning head; after completing the first positioning alignment, the upper-mount controller controls the electric push rod to slowly extend towards the secondary positioning head of the machine. The contact process between the multi-dimensional feedback sensor and the secondary positioning head causes the multi-dimensional feedback sensor to generate an output signal. The upper-mount controller controls the six-degree-of-freedom adjustable platform to adjust in six degrees of freedom according to this output signal, so that the multi-dimensional feedback sensor and the secondary positioning head can precisely cooperate, thereby achieving secondary positioning alignment.

4. The feeding and discharging method according to claim 3, characterized in that: The multidimensional feedback sensor includes a six-dimensional force sensor and a guide pin installed at the end of the electric push rod. The guide pin is a square bar with chamfers. The secondary positioning head on the machine platform is a square hole. The upper controller analyzes the force direction output by the six-dimensional force sensor and controls the six-degree-of-freedom adjustable platform to adjust in six degrees of freedom, so that the guide pin accurately enters the square hole, thereby achieving secondary positioning and alignment.

5. The feeding and discharging method according to claim 3, characterized in that: The multidimensional feedback sensor is a six-dimensional micro-displacement sensor installed at the end of the electric push rod. The six-dimensional micro-displacement sensor includes a six-dimensional micro-displacement body, multiple radial micro-displacement sensors, and multiple axial micro-displacement sensors. The secondary positioning head on the machine is a square column. All micro-displacement sensors of the six-dimensional micro-displacement sensor are calibrated using a calibration fixture to obtain a reference value. The upper controller analyzes the difference between the displacement reading output by the six-dimensional micro-displacement sensor and the reference value, and controls the six-degree-of-freedom adjustable platform to adjust in six degrees of freedom, so that the six-dimensional micro-displacement sensor accurately fits into the square column, thereby achieving secondary positioning alignment.

6. The feeding and discharging method according to any one of claims 1 to 5, characterized in that: The loading and unloading device is a multi-axis robotic arm. After the docking mechanism located on the horizontal plane of the six-degree-of-freedom adjustable platform performs a first or second positioning alignment with the positioning mechanism on the machine, the multi-axis robotic arm completes the initial loading or unloading through teaching and records the corresponding end pose and arrival path. Subsequent loading or unloading is automatically completed based on the results of the initial teaching record.

7. The loading and unloading method according to any one of claims 1 to 6, characterized in that: The six-degree-of-freedom adjustable platform is a Stewart-structured parallel robot.

8. The loading and unloading method according to any one of claims 1 to 7, characterized in that: The primary positioning identifier is a QR code with visual positioning function and ID information; the primary positioning camera obtains the six-dimensional information of the QR code in the camera coordinate system and the ID information contained in the QR code by taking pictures of the QR code and processing it with algorithms; each QR code serving as a primary positioning identifier on each machine has unique ID information.

9. A composite robot, characterized in that: The composite robot includes a mobile chassis and a superstructure. The superstructure has a six-degree-of-freedom adjustable platform. The lower plane of the six-degree-of-freedom adjustable platform is fixedly connected to the mobile chassis. The upper plane of the six-degree-of-freedom adjustable platform is equipped with a docking mechanism and a loading / unloading device. The six-degree-of-freedom adjustable platform is a Stewart-structured parallel robot. The docking mechanism includes a primary positioning camera for primary positioning and an electric push rod and a multi-dimensional feedback sensor for secondary positioning; the multi-dimensional feedback sensor includes a six-dimensional force sensor and a guide pin installed at the end of the electric push rod, the guide pin being a square bar with chamfers; The loading and unloading device is a multi-axis robotic arm; The upper part is equipped with an upper part controller, which uniformly controls the six-degree-of-freedom adjustable platform, docking mechanism and loading / unloading device, and realizes loading or unloading according to the loading / unloading method of any one of claims 1 to 3.

10. A composite robot, characterized by: The composite robot includes a mobile chassis and a superstructure. The superstructure has a six-degree-of-freedom adjustable platform. The lower plane of the six-degree-of-freedom adjustable platform is fixedly connected to the mobile chassis. The upper plane of the six-degree-of-freedom adjustable platform is equipped with a docking mechanism and a loading / unloading device. The six-degree-of-freedom adjustable platform is a Stewart-structured parallel robot. The docking mechanism includes a primary positioning camera for primary positioning and an electric push rod and a multi-dimensional feedback sensor for secondary positioning; the multi-dimensional feedback sensor is a six-dimensional micro-displacement sensor installed at the end of the electric push rod, and the six-dimensional micro-displacement sensor includes one six-dimensional micro-displacement body, four radial micro-displacement sensors, and four axial micro-displacement sensors. The loading and unloading device is a multi-axis robotic arm; The upper part is equipped with an upper part controller, which uniformly controls the six-degree-of-freedom adjustable platform, docking mechanism and loading / unloading device, and realizes loading or unloading according to the loading / unloading method of any one of claims 1 to 3.

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