A robot CNC feeding and discharging method and device

Abstract

The application belongs to the technical field of machine vision fusion application, and particularly relates to a robot CNC feeding and discharging method and device; the device comprises a composite robot, a CNC machine tool and a teaching workpiece; the composite robot comprises a moving chassis, a mechanical arm, a feeding and discharging clamp jaw and a 2D camera, the 2D camera and the feeding and discharging clamp jaw are installed on an installation platform at the end of the mechanical arm; the CNC machine tool has a first 2D positioning mark and a CNC material seat with a fixed relative position; the top of the teaching workpiece has a second 2D positioning mark; the robot CNC feeding and discharging is divided into a deployment stage and a feeding and discharging stage; the first 2D positioning mark and the second 2D positioning mark are used in the deployment stage, the teaching position of the second 2D positioning mark on the top of the teaching workpiece is recognized through the 2D camera, and the relative position relative to the first 2D positioning mark is obtained; the teaching position of the machined workpiece on the material seat in the CNC machine tool does not need to be observed carefully by the human eye, the teaching efficiency in the deployment stage is greatly improved, and the robot feeding and discharging in the CNC machine tool scene with a small internal space becomes feasible; the first 2D positioning mark is used as the base coordinate of the best feeding and discharging pose TCP, so that the 2D camera does not need to take a photo of the CNC material seat in the feeding and discharging stage, and the influence of the cutting chip liquid, metal chips and the discharged workpiece on the camera algorithm accuracy is avoided.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of machine vision fusion application, and in particular to a robot CNC feeding and discharging method and device. BACKGROUND

[0002] In the development process of manufacturing automation, robots are increasingly widely used for CNC machine tool feeding and discharging. A composite robot integrates a movable chassis and a mechanical arm, and the end of the mechanical arm can carry a feeding and discharging gripper and a camera. The camera, as a key 3D positioning sensor, mainly includes 2D cameras and 3D cameras, which have significant differences in working principles and advantages and disadvantages in the CNC feeding and discharging scene. The present application takes a 2D camera with lower cost as an example.

[0003] A 2D camera only has two-dimensional information, and when used for CNC feeding and discharging, a special 2D feature pattern (i.e., a 2D positioning mark) needs to be used to obtain 3D information to align the material with the CNC material seat. The 2D feature pattern has a fixed size and a recognizable orientation, and needs to be fixed near the CNC material seat during use, and maintains a fixed spatial relationship with the CNC material seat each time feeding and discharging is performed. Through an algorithm, the accurate pose (including three-dimensional coordinates x / y / z and three-axis rotation angles rx / ry / rz) in the 2D camera coordinate system can be calculated according to the fixed size.

[0004] When feeding and discharging based on a 2D camera, the process is divided into a deployment stage and a feeding and discharging stage. In the deployment stage, the best TCP pose for feeding and discharging and the pose phase difference of the 2D positioning mark are determined through teaching. In the subsequent feeding and discharging stage, the 2D camera is used to take a picture of the 2D positioning mark for positioning, and the pose phase difference data saved in the deployment stage is used to complete accurate feeding and discharging. However, the material seat of each CNC machine tool needs to be taught, and if there are multiple material seats in one machine tool, the teaching time in the deployment stage will also be greatly increased. Most CNC machine tools have relatively small internal spaces. At the same time, the robot CNC feeding and discharging process generally needs to be used in cooperation with a feeding table and a discharging table. Each table generally has dozens of material positions and one 2D positioning mark, and the pose phase difference between the 2D positioning mark and the dozens of material positions on the same table is also calibrated through teaching.

[0005] Currently, in the field of robot CNC feeding and discharging, the teaching action in the deployment stage is basically observed by the human eye at close range, which has the following shortcomings: it takes a long time, the teaching accuracy is related to the observation ability of the human eye, and the narrow space inside the CNC machine tool is not convenient for the human eye to observe. Based on these practical difficulties, the present application uses a first 2D positioning mark and a second 2D positioning mark to obtain the teaching pose by using a 2D camera vision algorithm, improves the deployment efficiency, reduces the deployment difficulty, and promotes the wide application of the technology. SUMMARY

[0006] In order to make up for the deficiencies of the prior art, the present application provides a robot CNC feeding and discharging device, which comprises a composite robot, a CNC machine tool and a teaching workpiece;

[0007] The composite robot comprises a mobile chassis, a mechanical arm, a feeding and discharging gripper and a 2D camera; one end of the mechanical arm is installed on the mobile chassis, and the other end is installed with the feeding and discharging gripper and the 2D camera through an installation platform at the end of the mechanical arm;

[0008] The CNC machine tool has a CNC material seat and a first 2D positioning mark; the CNC material seat and the first 2D positioning mark on the CNC machine tool have a fixed relative position; the CNC material seat is used for carrying and clamping a workpiece to be processed; and the first 2D positioning mark is used for identifying the relative relationship of the optimal feeding and discharging pose of the feeding and discharging gripper;

[0009] The teaching workpiece has a second 2D positioning mark on the top and has a base same as the workpiece to be processed, and can be placed in the CNC material seat like the workpiece to be processed.

[0010] The mobile chassis of the composite robot adopts a laser SLAM navigation mode to navigate to a specified position in front of a CNC machine tool; each CNC machine tool is provided with a navigation station thereof, and all the navigation stations are marked on a laser SLAM navigation map; the composite robot is dispatched to the navigation station corresponding to any CNC machine tool with feeding and discharging requirements through the navigation stations on the laser SLAM navigation system and the navigation map.

[0011] The first 2D positioning mark and the 2D camera are used for the deployment stage and the feeding and discharging stage of the CNC machine tool and the composite robot, and the teaching workpiece is used for the deployment stage; in the deployment stage, the first 2D positioning mark fixed in the CNC machine tool and the second 2D positioning mark on the top of the teaching workpiece are photographed by the 2D camera, and the relative pose relationship of the second 2D positioning mark relative to the first 2D positioning mark is calculated; the fixed offset between the known pose of the second 2D positioning mark and the optimal feeding and discharging pose TCP is used to obtain the relative pose relationship between the optimal feeding and discharging pose TCP and the first 2D positioning mark; the relative pose relationship data are recorded by the mechanical arm control software for use in the feeding and discharging stage; and the mechanical arm tool center point TCP pose when the composite robot photographs the first 2D positioning mark is also recorded by the mechanical arm control software for use in the feeding and discharging stage.

[0012] Meanwhile, the application provides a robot CNC feeding and discharging method, which is suitable for the robot CNC feeding and discharging device and characterized by the following steps in the deployment stage: a 2D camera is used to take pictures of a first 2D positioning mark fixed in a CNC machine tool and a second 2D positioning mark located on the top of a teaching workpiece, and the relative pose relationship of the second 2D positioning mark relative to the first 2D positioning mark is calculated; the fixed deviation of the second 2D positioning mark and the feeding and discharging clamping position on the workpiece to be processed is used to obtain the relative pose relationship of the optimal feeding and discharging pose TCP relative to the first 2D positioning mark; the relative pose relationship data is recorded by the mechanical arm control software for use in the feeding and discharging stage.

[0013] The deployment stage of each CNC machine tool comprises the following steps:

[0014] Step one: the laser SLAM navigation system and the navigation station on the navigation map dispatch the composite robot to the navigation station corresponding to the CNC machine tool;

[0015] Step two: the 2D camera center at the end of the mechanical arm is adjusted to be close to a predetermined ideal value in the pose relationship of the first 2D positioning mark coordinate system by manual operation of the mechanical arm control software, the 2D camera takes pictures and calculates the actual value Z2D1 of the 2D camera center in the first 2D positioning mark coordinate system; the mechanical arm control software records a pose TCP1a of the end of the mechanical arm in the base coordinate system of the mechanical arm according to the pose TCP1 of the end of the mechanical arm in the base coordinate system of the mechanical arm when the composite robot takes pictures of the first 2D positioning mark, and TCP1a is compared with TCP1, and there is a distance deviation in the vertical direction of the first 2D positioning mark;

[0016] Step three: the 2D camera center at the end of the mechanical arm is adjusted to be close to a predetermined ideal value in the pose relationship of the second 2D positioning mark coordinate system by manual operation of the mechanical arm control software, and the 2D camera takes pictures and calculates the actual value Z2D2 of the 2D camera in the second 2D positioning mark coordinate system;

[0017] Step four: the fixed offset ΔGJ of the pose of the second 2D positioning mark and the optimal feeding and discharging pose TCP is used to adjust the end of the mechanical arm TCP to the optimal feeding and discharging pose by manual operation of the mechanical arm control software with the second 2D positioning mark coordinate system as the reference coordinate; the pose Z2D3 of the end of the mechanical arm TCP in the first 2D positioning mark coordinate system at this time is recorded by the mechanical arm control software for use in the feeding and discharging stage.

[0018] Each feeding and discharging stage of each CNC machine tool comprises the following steps:

[0019] Step one: the laser SLAM navigation system and the navigation station on the navigation map dispatch the composite robot to the navigation station corresponding to the CNC machine tool;

[0020] Step two: according to the TCP1a recorded in the deployment stage, the mechanical arm control software autonomously guides the mechanical arm end to the first 2D positioning mark to reach the long-distance shooting point; at this time, the 2D camera center in the first 2D positioning mark coordinate system is obtained by shooting Z2D1a; referring to the obtained Z2D1a, the mechanical arm end is guided to the ideal shooting pose again, and the 2D camera center in the first 2D positioning mark coordinate system is obtained by shooting again Z2D1n;

[0021] Step three: according to the best loading and unloading pose TCP in the deployment stage recorded in the first 2D positioning mark coordinate system Z2D3, taking the first 2D positioning mark coordinate system as the reference coordinate system, the mechanical arm control software autonomously guides the mechanical arm end to continue to move Z2D3-Z2D1n, at this time, the mechanical arm end reaches the predetermined best loading and unloading pose, and the opening and closing of the loading and unloading gripper is completed.

[0022] The present application has the following advantages:

[0023] The first 2D positioning mark and the second 2D positioning mark are used in the deployment stage of the present application, the teaching position of the second 2D positioning mark on the top of the teaching workpiece is recognized by the 2D camera, and the relative position relative to the first 2D positioning mark is obtained, without the need for the human eye to closely observe the teaching position of the machined workpiece on the internal material seat of the CNC machine tool, the teaching efficiency in the deployment stage is greatly improved, and the deployment of the robot for loading and unloading in the scene of the CNC machine tool with small internal space becomes feasible; the first 2D positioning mark is used as the base coordinate of the best loading and unloading pose TCP, so that the 2D camera does not need to take pictures of the CNC material seat in the loading and unloading stage, and the influence of the cutting chip liquid, metal chips and unloaded workpieces on the camera algorithm accuracy is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0024] The present application will be further described below in conjunction with the drawings.

[0025] Figure 1 is the 2D camera and 2D positioning mark used in the present application;

[0026] Figure 2 is the teaching workpiece used in the present application;

[0027] Figure 3 is the composition device in the deployment stage of the present application;

[0028] Figure 4 is the composition device in the loading and unloading stage of the present application. DETAILED DESCRIPTION

[0029] In order to make the technical means, creative features, purposes and effects realized by the present application easy to understand, the present application will be further described below in conjunction with specific embodiments.

[0030] Embodiment one: as Figures 1-3 , a robot CNC feeding and discharging device used in the deployment stage of the present application, comprising a composite robot, a CNC machine tool and a teaching workpiece;

[0031] Figure 1 is a 2D camera and a 2D positioning mark used by the present application, a black square composed of an outer side length of 50mm square and an inner side length of 40mm square is a kind of 2D feature pattern, and the TM character inside is used as orientation recognition. The first 2D positioning mark and the second 2D positioning mark are both 2D positioning marks of the same specification.

[0032] Figure 2 is a teaching workpiece used by the present application, the teaching workpiece has a second 2D positioning mark on the top, has a base as the same as the machined workpiece, and can be placed in the CNC material seat as the machined workpiece. It can be seen that the center position of the second 2D positioning mark has a fixed deviation ΔGJ with the feeding and discharging clamping position on the machined workpiece, such as (Z=20mm, Y=50mm, and others are 0).

[0033] Figure 3 is a component device in the deployment stage of the present application, comprising a composite robot, a CNC machine tool and a teaching workpiece.

[0034] The composite robot comprises a mobile chassis, a mechanical arm, a feeding and discharging clamp (not shown in the figure, different due to different clamped materials), and a 2D camera. One end of the mechanical arm is installed on the mobile chassis, and the other end is installed with the feeding and discharging clamp and the 2D camera through the mechanical arm end.

[0035] Each CNC machine tool has a CNC material seat and a first 2D positioning mark. The relative position relationship between the CNC material seat and the first 2D positioning mark on the CNC machine tool is fixed and unchanged. The CNC material seat is used to carry and clamp the machined workpiece for CNC machining, and the first 2D positioning mark is used to identify the relative pose of the tool center point TCP at the end of the mechanical arm in the first 2D positioning mark coordinate system when the best feeding and discharging pose is achieved.

[0036] The teaching workpiece has a second 2D positioning mark on the top, has a base as the same as the machined workpiece, and can be placed on the CNC material seat as the machined workpiece.

[0037] The mobile chassis of the composite robot uses laser SLAM navigation method to navigate to a specified position in front of a certain CNC machine tool; each of the CNC machine tools is provided with a navigation station point, and all the navigation station points are marked on the laser SLAM navigation map. The composite robot is dispatched to the navigation station point corresponding to any CNC machine tool with feeding and discharging demand through the laser SLAM navigation system and the navigation station points on the navigation map, and the normal parking accuracy can be ensured within + / -10mm.

[0038] The first 2D positioning mark and the 2D camera are used for the deployment stage and the loading and unloading stage of the CNC machine tool and the composite robot, and the teaching workpiece is only used for the deployment stage. In the deployment stage, the first 2D positioning mark fixed in the CNC machine tool and the second 2D positioning mark located on the top of the teaching workpiece are photographed by the 2D camera, and the relative pose relationship of the second 2D positioning mark relative to the first 2D positioning mark is calculated. By using the known fixed deviation of the second 2D positioning mark and the loading and unloading clamping position on the machined workpiece, the relative pose relationship of the optimal loading and unloading pose TCP relative to the first 2D positioning mark is obtained. The relative pose relationship data is recorded by the robot control software, and is used for the loading and unloading stage. The robot control software also records the coordinates of the tool center point TCP of the composite robot in the robot coordinate system when the first 2D positioning mark is photographed, and is used for the loading and unloading stage.

[0039] A robot CNC loading and unloading method, the deployment stage of which comprises the following steps:

[0040] Step one: the laser SLAM navigation system and the navigation station on the navigation map dispatch the composite robot to the navigation station corresponding to a CNC machine tool;

[0041] Step Two: Using the robotic arm control software, the operator moves the center of the 2D camera at the end of the robotic arm until its pose in the first 2D positioning marker coordinate system approaches a predetermined ideal value (e.g., Z=200mm, others 0). A 2D photograph is taken, and the actual value Z2D1 of the 2D camera in the first 2D positioning marker coordinate system is calculated (e.g., Z=200.1mm, X=0.1mm, Y=-0.1mm, others 0). The robotic arm control software records the pose TCP1 of the end of the robotic arm in the robotic arm base coordinate system when the composite robot takes a photograph of the first 2D positioning marker. In practice, it is preferable to record a pose TCP1a of the end of the robotic arm in the robotic arm base coordinate system during deployment. Comparing TCP1a and TCP1, there is a distance deviation in the vertical direction of the first 2D positioning marker, for example, a decrease of 10cm in the Y direction of the robotic arm coordinate system. This is used to absorb the stopping error of the moving chassis and is used during the loading and unloading stages. The purpose of reserving this 10cm is to ensure that, relative to the deployment stage, the composite robot can achieve a certain position in the loading and unloading stages. There are different stopping errors before the CNC machine tool stops, including errors in forward / backward and rotation angles. The robotic arm first moves according to the TCP1a coordinate system. After stopping, the 2D camera takes a picture of the first 2D positioning mark. At this time, the shooting distance is relatively far and the angle may be large, resulting in the pose relationship Z2D1a of the 2D camera center relative to the first 2D positioning mark (e.g., Z=290mm, X=10mm, Y=8mm, rx=5°, ry=5°, rz=2°). The accuracy of Z2D1a is low. Referring to the obtained low-precision relative pose relationship Z2D1a, the robotic arm is automatically guided to the ideal shooting pose (e.g., Z=200mm, others are 0) for more accurate shooting positioning. The actual value Z2D1 (e.g., Z=200.1mm, X=0.1mm, Y=-0.1mm, others are 0) of the pose relationship of the 2D camera center at the end of the robotic arm in the first 2D positioning mark coordinate system is close to a predetermined ideal (e.g., Z=200mm, others are 0) in the coordinate system.

[0042] Step 3: Manually use the robotic arm control software to move the center of the 2D camera at the end of the robotic arm so that its pose in the second 2D positioning marker coordinate system is close to a predetermined ideal value (e.g., Z=200mm, others are 0). Take a 2D picture and calculate the actual value Z2D2 of the 2D camera in the second 2D positioning marker coordinate system (e.g., Z=200.3mm, X=0.1mm, Y=-0.1mm, others are 0).

[0043] Step four: use the known second 2D positioning mark to identify the pose and the fixed offset AGJ (such as Z=20mm, Y=50mm, and 0 for others) of the best loading and unloading pose TCP, and use the second 2D positioning mark coordinate system as the reference coordinate, manually adjust the TCP of the robot arm end to the best loading and unloading pose by using the robot arm control software, and record the pose Z2D3 of the robot arm end TCP in the first 2D positioning mark coordinate system at this time by using the robot arm control software for the loading and unloading stage.

[0044] Embodiment two: as Figure 4 , the robot CNC loading and unloading device used in the present application, compared with the deployment stage, no longer needs to teach the workpiece, which includes a composite robot and a CNC machine tool.

[0045] A robot CNC loading and unloading method, which uses the teaching data TCP1a and Z2D3 recorded in the deployment stage, a 2D camera, and a first 2D positioning mark to accurately calculate the loading and unloading pose, and each loading and unloading stage includes the following steps:

[0046] Step one: the laser SLAM navigation system and the navigation station on the navigation map dispatch the composite robot to the navigation station corresponding to a certain CNC machine tool;

[0047] Step two: according to the TCP1a recorded during the actual deployment in the deployment stage, the robot arm control software autonomously guides the robot arm end to move to the first 2D positioning mark first shooting point, called the long-distance shooting point, at this time the shooting distance is far and the angle may be large, and the accuracy of the relative pose relationship Z2D1an (such as Z=290mm, X=10mm, Y=8mm, rx=5°, ry=5°, rz=2°) of the 2D camera center in the first 2D positioning mark coordinate system is low; therefore, referring to the obtained low-precision relative pose relationship Z2D1an, the robot arm end is guided again to the ideal shooting pose (such as Z=200mm, and 0 for others), called the short-distance shooting point, and the pose relationship Z2D1n of the 2D camera center of the robot arm end in the first 2D positioning mark coordinate system is calculated again; the Z2D1n obtained each time the loading and unloading has some error from the ideal relative pose (such as Z=200mm, and 0 for others), but the error is generally not large; in this way, through the two shootings of the long-distance shooting point and the short-distance shooting point, the risk of collision between the robot arm and the CNC caused by the error of each stop of the chassis is avoided, and at the same time, the high-precision calculation of the relative pose of the 2D camera center of the robot arm end and the first 2D positioning mark is ensured;

[0048] Step three: record the pose relationship Z2D3 of the best loading and unloading pose TCP in the first 2D positioning mark coordinate system according to the deployment stage, take the first 2D positioning mark coordinate system as the reference coordinate system, and the mechanical arm control software autonomously guides the mechanical arm end to continue moving Z2D3-Z2D1n, at this time, the mechanical arm end reaches the predetermined best loading and unloading pose; the loading and unloading are completed through the opening and closing of the loading and unloading gripper.

[0049] The above two embodiments are only used to illustrate the technical solutions of the present application but not to limit it. Although the present application is described in detail with reference to the above embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, and any modification or equivalent replacement should be covered in the protection scope of the claims of the present application.

Claims

1. A robot CNC loading and unloading method, characterized in that: The method uses a robotic device; The robotic device includes a composite robot, a CNC machine tool, and a teach pendant. The composite robot includes a mobile chassis, a robotic arm, loading and unloading grippers, and a 2D camera. One end of the robotic arm is mounted on the mobile chassis, and the other end is mounted on the loading and unloading grippers and the 2D camera via a mounting platform at the end of the robotic arm. The CNC machine tool has a CNC material holder and a first 2D positioning mark. The relative positions of the CNC material holder and the first 2D positioning mark on the CNC machine tool are fixed. The CNC material holder is used to support and clamp the workpiece being processed. The first 2D positioning mark is used to mark the relative relationship of the optimal loading and unloading positions of the loading and unloading grippers. The teach pendant has a second 2D positioning mark on its top and a base identical to that of the workpiece being processed, and can be placed in the CNC material holder like the workpiece being processed. Each of the CNC machine tools is equipped with its own navigation station, and all navigation stations are marked on the laser SLAM navigation map; The CNC loading and unloading method is divided into a deployment phase and a loading and unloading phase. The deployment phase includes the following steps: Step 1: Use the laser SLAM navigation system and navigation stations on the navigation map to schedule the composite robot to the corresponding navigation station on the CNC machine tool; Step 2: Manually adjust the pose of the 2D camera center at the end of the robotic arm to be close to a predetermined ideal value in the first 2D positioning mark coordinate system using the robotic arm control software. The 2D camera takes a picture and calculates the actual value Z2D1 of the 2D camera center in the first 2D positioning mark coordinate system. The robotic arm control software records a pose TCP1a of the end of the robotic arm in the robotic arm base coordinate system based on the pose TCP1 of the end of the robotic arm in the robotic arm base coordinate system when the composite robot takes a picture of the first 2D positioning mark. Comparing TCP1a with TCP1, there is a distance deviation in the vertical direction of the first 2D positioning mark. Step 3: Manually use the robotic arm control software to adjust the pose of the 2D camera center at the end of the robotic arm to be close to a predetermined ideal value in the second 2D positioning mark coordinate system, take a 2D picture and calculate the actual value Z2D2 of the 2D camera in the second 2D positioning mark coordinate system. Step 4: Using the known fixed offset ΔGJ between the second 2D positioning mark pose and the optimal loading / unloading pose TCP, and taking the second 2D positioning mark coordinate system as the reference coordinate, manually adjust the end effector TCP of the robotic arm to the optimal loading / unloading pose using the robotic arm control software; record the pose Z2D3 of the end effector TCP of the robotic arm in the first 2D positioning mark coordinate system at this time using the robotic arm control software, for use in the loading / unloading stage.

2. The robot CNC loading and unloading method according to claim 1, characterized in that: The loading and unloading stage includes the following steps: Step 1: Use the laser SLAM navigation system and navigation stations on the navigation map to schedule the composite robot to the corresponding navigation station on the CNC machine tool; Step 2: Based on the TCP1a recorded during the actual deployment phase, the robotic arm control software autonomously guides the end effector of the robotic arm to the far-distance photo point of the first 2D positioning marker; at this time, the pose relationship Z2D1a of the 2D camera center in the first 2D positioning marker coordinate system is obtained; referring to the obtained Z2D1a, the robotic arm is autonomously guided to the end effector of the robotic arm to the ideal photo pose again, and the pose relationship Z2D1n of the 2D camera center at the end effector of the robotic arm in the first 2D positioning marker coordinate system is obtained again. Step 3: Based on the optimal loading / unloading pose recorded during the deployment phase, the pose relationship Z2D3 of the first 2D positioning marker coordinate system is used as the reference coordinate system. The robotic arm control software autonomously guides the end effector of the robotic arm to continue moving Z2D3-Z2D1n. At this time, the end effector of the robotic arm reaches the predetermined optimal loading / unloading pose, and the loading / unloading is completed by opening and closing the loading / unloading grippers.

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