阅读说明：本技术 一种用于标定多机器人协同工作坐标系的装置及标定方法 (Device and method for calibrating multi-robot cooperative work coordinate system ) 是由 岑洎涛 赵天光 易京亚 马章宇 于 2020-04-17 设计创作，主要内容包括：本发明公开了一种用于标定多机器人协同工作坐标系的装置及标定方法,采用变形传感器和主动式电容标定球,完全依靠标定装置来采集数据,对比靠肉眼判断标定,精度大大提升；采用的传感器是常规传感器,易替代,根据使用场景区分精度要求,从中选择合适传感器来组装最优性价比标定装置；本方法步骤简单,可自动完成标定操作,对多机器人协作可实现快速标定；本装置小型便携,适应不同生产场合；本方法不会使人员疲劳,适合多次重复标定,不会有操作失误,具有高稳定性；本标定球可通过定制方式装配到机器人末端,借助吸力标定靶进行工具坐标系标定,由此获得较高工具坐标系精度；定制标定球配合触摸板,可作为标准工件辅助机器人进行各类精度测试。(The invention discloses a device and a calibration method for calibrating a multi-robot cooperative working coordinate system, wherein a deformation sensor and an active capacitance calibration ball are adopted, data are acquired completely by a calibration device, and the calibration is judged by naked eyes in comparison, so that the precision is greatly improved; the adopted sensors are conventional sensors and are easy to replace, and according to the distinguishing precision requirement of the use scene, a proper sensor is selected to assemble the optimal cost performance calibration device; the method has simple steps, can automatically finish the calibration operation, and can realize quick calibration for the cooperation of multiple robots; the device is small and portable, and is suitable for different production occasions; the method does not cause fatigue of personnel, is suitable for repeated calibration for many times, does not have misoperation, and has high stability; the calibration ball can be assembled at the tail end of the robot in a customized mode, and the tool coordinate system calibration is carried out by means of the suction calibration target, so that higher tool coordinate system precision is obtained; the customized calibration ball is matched with the touch pad, and can be used as a standard workpiece auxiliary robot to perform various precision tests.)

1. A device for calibrating a multi-robot cooperative work coordinate system is characterized by comprising a calibration tool head, a suction calibration target (6) and a calibration plate mechanism:

the calibration tool head comprises a calibration ball (5) and a deformation sensor (3) which are arranged at a flange plate at the tail end of the robot through a connecting structure, and the calibration ball (5) is connected with the deformation sensor (3);

the suction calibration target (6) is fixed in position in the calibration process and is attracted with the calibration ball through multiple points to determine a tool coordinate system based on the robot execution tail end;

the calibration plate mechanism comprises a touch screen (7), the position of the touch screen (7) is fixed in the calibration process, and the touch screen (7) is matched with the calibration ball (5) through a multipoint method to determine a user coordinate system of the robot-based execution tail end on the touch screen (7);

under the condition that the robot base is fixed, acquiring a base coordinate system of the robot, and finally obtaining the conversion relation between the base coordinate system of the robot and a user coordinate system by calculating the conversion relation between the base coordinate system of the same robot and a tool coordinate system and the conversion relation between the tool coordinate system and the user coordinate system; the respective user coordinate systems of different robots are established on the touch screen (7), and the conversion relation between the base coordinate systems of different robots is finally obtained, so that the calibration of the multi-robot cooperative work coordinate system is completed.

2. The apparatus for calibrating the multi-robot cooperative coordinate system as claimed in claim 1, wherein a concave groove (61) matching with the spherical surface of the calibration ball (5) is formed at the top end of the suction calibration target (6), and the spherical surface of the calibration ball (5) is required to be completely attached to the concave groove (61) of the suction calibration target (6) during calibration.

3. The apparatus for calibrating a multi-robot co-operating coordinate system as claimed in claim 2, wherein the calibration ball (5) and the suction calibration target (6) are magnetically attracted to each other.

4. The apparatus for calibrating a multi-robot co-operating coordinate system as claimed in claim 2, wherein the calibration ball (5) and the suction calibration target (6) are engaged with each other by vacuum suction.

5. Device for calibrating a multi-robot co-operating coordinate system according to any of the claims 3 or 4, characterized in that the calibration balls (5) are active capacitive calibration balls, which are powered by a power supply.

6. The device for calibrating the multi-robot cooperative work coordinate system according to claim 5, wherein the deformation sensor (3) is connected with a control moving module, the control moving module is connected with the robot, the deformation sensor (3) feeds back a real-time acquired numerical value to the control moving module, and the control moving module guides the robot to move according to the fed-back numerical value, so that the spherical surface of the calibration ball (5) is quickly and completely attached to the concave groove (61) of the suction calibration target (6).

7. The device for calibrating the multi-robot cooperative work coordinate system according to claim 5, further comprising an LED indicator light and a zero setting key for realizing light-on prompt according to the deformation amount collected by the deformation sensor (3), wherein the LED indicator light is connected with the deformation sensor (3), and the zero setting key is connected with the deformation sensor (3).

8. The device for calibrating the multi-robot co-operating coordinate system as claimed in claim 5, wherein the touch screen (7) is a high hardness glass high PPI touch screen.

9. Device for calibrating a multi-robot co-operating coordinate system according to claim 8, characterized in that the touch screen (7) is fixed by a fixing tool during calibration.

10. A calibration method for calibrating a device for multi-robot co-operating coordinate system according to any one of claims 1-9, comprising the steps of:

s1: determining a base coordinate system of each robot: fixing the robots to be calibrated according to the cooperation relationship, ensuring that the robot base coordinate system does not displace any more in the calibration process, and obtaining the base coordinate system of each robot;

s2: installing a calibration tool head on the tail end of each robot;

s3: fixing a suction calibration target (6), pre-zeroing a deformation sensor (3), then enabling a robot to drive a calibration ball (5) to be close to the suction calibration target (6) under the condition that the posture is kept unchanged, enabling the numerical value of the deformation sensor (3) to be changed, controlling the position of the execution tail end of the robot until the deformation sensor (3) returns to zero again, completely attaching the spherical surface of the calibration ball (5) to a concave groove (61) of the suction calibration target (6) at the moment, and acquiring the position information of the current calibration ball (5);

s4: repeating the step of S3 for a set number of times, changing the posture of the robot once per execution, to determine the tool coordinate system of the robot by a multi-point method;

s5: repeatedly performing S3 to S4 by the number of robots to determine tool coordinate systems of all the robots;

s6: grouping all the robots into a group according to two adjacent robots;

s7: fixing a calibration plate device between a group of two robots;

s8: pre-zeroing the deformation sensor (3), driving the calibration ball (5) to touch on the touch screen (7) by the robot under the condition that the posture is kept unchanged, and moving the robot to execute the calibration ball (5) with the tail end driving the posture unchanged to slowly move on the touch screen (7) after the data sensed by the deformation sensor (3) is changed until the data of the deformation sensor (3) returns to zero and the touch screen (7) can measure the position data of a touch point;

s9: repeatedly executing S8 for a set number of times, changing the position of the calibration ball (5) on the touch screen (7) on the premise of not changing the posture of the robot once each execution, and executing a preset value of the distance between the two execution positions to determine the user coordinate system of the robot;

s10: performing S8 to S9 on both the two robots of the same group to determine respective user coordinate systems of the two robots of the same group, and acquiring a relationship of the user coordinate systems between the two robots of the same group;

s11: establishing a relation of a base coordinate system between two robots in the same group: calculating the conversion relation between the base coordinate system and the tool coordinate system of the same robot and the conversion relation between the tool coordinate system and the user coordinate system, and finally obtaining the conversion relation between the base coordinate system and the user coordinate system of the robot; finally establishing the relation of a base coordinate system between the two robots in the same group according to the relation of the user coordinate systems between the two robots in the same group;

s12: and repeatedly executing S7 to S11 until all the robots are linked by the base coordinate system.

Technical Field

The invention relates to the technical field of calibration, in particular to a device and a method for calibrating a multi-robot cooperative working coordinate system.

Background

With the continuous development of modern industrial manufacturing technology, multi-robot cooperation has become a research hotspot in the robot field. The calibration problem of a multi-robot system is also of great concern as one of the key technologies, and the problems of cost performance of a calibration tool, usability of a calibration method and the like become an important problem in current robot industry research.

The calibration methods of the existing robot system generally fall into two categories: one is calibration by means of external advanced equipment such as a laser tracker or dual cameras. The equipment has high precision and reliability, but the calibration process is complex and is particularly expensive, and the method has strong conditionality and dependence, and is generally used in precise occasions and is not suitable for production sites with severe environment because the method has high requirement on the environment and has overhigh technical requirement on operators.

The other type of calibration method is a calibration method without using precise external equipment, and two robots are respectively contacted with a calibration tool in sequence through a reference calibration tool, so that the relative relation of the two robots to calibration work is obtained, and the base coordinate system relation of the two robots can be obtained through conversion calculation. The method has the advantages of rapidness and simplicity, but is only suitable for occasions with low precision requirements due to the fact that many manual operations are involved.

Therefore, the prior art still needs to be improved and developed.

Disclosure of Invention

In order to solve the above-mentioned technical problem, the present invention provides a device and a calibration method for calibrating a multi-robot cooperative working coordinate system.

The technical scheme of the invention is as follows:

an apparatus for calibrating a multi-robot co-operating coordinate system, comprising a calibration tool head, a suction calibration target and a calibration plate mechanism:

the calibration tool head comprises a calibration ball and a deformation sensor which are arranged at a flange plate at the tail end of the robot through a connecting structure, and the calibration ball is connected with the deformation sensor;

the suction calibration target is fixed in position in the calibration process and is in multi-point attraction with the calibration ball to determine a tool coordinate system based on the robot execution tail end;

the calibration plate mechanism comprises a touch screen, the position of the touch screen is fixed in the calibration process, and the touch screen and the calibration ball are matched through a multipoint method to determine a user coordinate system of the robot-based execution tail end on the touch screen;

under the condition that the robot base is fixed, acquiring a base coordinate system of the robot, and finally obtaining the conversion relation between the base coordinate system of the robot and a user coordinate system by calculating the conversion relation between the base coordinate system of the same robot and a tool coordinate system and the conversion relation between the tool coordinate system and the user coordinate system; and finally, obtaining a conversion relation between the base coordinate systems of the different robots by establishing respective user coordinate systems of the different robots on the touch screen, thereby completing the calibration of the multi-robot cooperative work coordinate system.

The device for calibrating the multi-robot cooperative working coordinate system is characterized in that a concave groove matched with the spherical surface of the calibration ball is formed in the top end of the suction calibration target, and the spherical surface of the calibration ball is required to be completely attached to the concave groove of the suction calibration target during calibration.

The device for calibrating the multi-robot cooperative working coordinate system is characterized in that the calibration ball and the suction calibration target are mutually attracted in a magnetic mode.

The device for calibrating the multi-robot cooperative working coordinate system is characterized in that the calibration ball and the suction calibration target are mutually attracted in a vacuum adsorption mode.

The device for calibrating the multi-robot cooperative working coordinate system is characterized in that the calibration tool head further comprises a deformation sensor, the calibration ball adopts an active capacitance calibration ball, and the active capacitance calibration ball supplies power to the active capacitance calibration ball through a power supply; the active capacitance calibration ball is connected with the deformation sensor.

The device for calibrating the multi-robot cooperative working coordinate system is characterized in that the deformation sensor is connected with the control moving module, the control moving module is connected with the robot, the deformation sensor feeds back a real-time acquired numerical value to the control moving module, and the control moving module guides the robot to move according to the fed-back numerical value, so that the spherical surface of the calibration ball is quickly and completely attached to the concave groove of the suction calibration target.

The device for calibrating the multi-robot cooperative working coordinate system further comprises an LED indicator light and a zero setting key, wherein the LED indicator light and the zero setting key are used for realizing light-on prompting according to the deformation quantity collected by the deformation sensor, the LED indicator light is connected with the deformation sensor, and the zero setting key is connected with the deformation sensor.

The device for calibrating the multi-robot cooperative working coordinate system is characterized in that the touch screen is a high-hardness glass high-PPI touch screen.

The device for calibrating the multi-robot cooperative work coordinate system is characterized in that the touch screen is fixed in the calibration process through a fixing tool.

A calibration method for calibrating a device for calibrating a multi-robot cooperative work coordinate system as described in any one of the above, comprising the following steps:

s1: determining a base coordinate system of each robot: fixing the robots to be calibrated according to the cooperation relationship, ensuring that the robot base coordinate system does not displace any more in the calibration process, and obtaining the base coordinate system of each robot;

s2: installing a calibration tool head on the tail end of each robot;

s3: fixing the suction calibration target, pre-zeroing the deformation sensor, driving a calibration ball to be close to the suction calibration target under the condition that the posture of the robot is kept unchanged, changing the numerical value of the deformation sensor, controlling the position of the execution tail end of the robot until the deformation sensor returns to zero again, completely attaching the spherical surface of the calibration ball to the concave groove of the suction calibration target at the moment, and acquiring the position information of the current calibration ball;

s4: repeating the step of S3 for a set number of times, changing the posture of the robot once per execution, to determine the tool coordinate system of the robot by a multi-point method;

s5: repeatedly performing S3 to S4 by the number of robots to determine tool coordinate systems of all the robots;

s6: grouping all the robots into a group according to two adjacent robots;

s7: fixing a calibration plate device between a group of two robots;

s8: pre-zeroing the deformation sensor, driving the calibration ball to touch on the touch screen by the robot under the condition that the posture of the robot is kept unchanged, and moving the calibration ball with the unchanged posture on the touch screen slowly by the mobile robot after the data sensed by the deformation sensor is changed until the data of the deformation sensor returns to zero and the touch screen can measure the position data of a touch point;

s9: repeatedly executing S8 for a set number of times, changing the position of the calibration ball on the touch screen on the premise of not changing the posture of the robot once execution, and executing a preset value of the distance between the positions twice to determine a user coordinate system of the robot;

s10: performing S8 to S9 on both the two robots of the same group to determine respective user coordinate systems of the two robots of the same group, and acquiring a relationship of the user coordinate systems between the two robots of the same group;

s11: establishing a relation of a base coordinate system between two robots in the same group: calculating the conversion relation between the base coordinate system and the tool coordinate system of the same robot and the conversion relation between the tool coordinate system and the user coordinate system, and finally obtaining the conversion relation between the base coordinate system and the user coordinate system of the robot; finally establishing the relation of a base coordinate system between the two robots in the same group according to the relation of the user coordinate systems between the two robots in the same group;

s12: and repeatedly executing S7 to S11 until all the robots are linked by the base coordinate system.

The invention has the beneficial effects that: the invention provides a device and a calibration method for calibrating a multi-robot cooperative working coordinate system, wherein the device adopts a sensitive deformation sensor and an active capacitance calibration ball, and completely collects data by a calibration device, so that the precision is greatly improved compared with a general calibration mode which depends on the judgment of naked eyes of an operator; in addition, the sensors adopted by the scheme are all conventional sensors, are easy to replace, and can be used for selecting proper sensors to assemble a calibration device with the optimal cost performance according to the requirement of distinguishing precision of the use scenes; the calibration method provided by the technical scheme has simple steps, even can automatically complete the calibration operation, and the calibration can not be avoided frequently by the cooperation of multiple robots; the technical calibration device is small and portable, can adapt to different production occasions, is in conventional operation during calibration, has a large number of repeated operation times, does not cause fatigue of operators by the operation method of the technical scheme, and does not have operation errors, so the system scheme of the technical scheme has high stability; the active capacitance calibration ball of the technical scheme can be assembled on a robot tail end tool in a customized mode, and the tool coordinate system calibration is carried out by means of the suction calibration target, so that higher tool coordinate system precision can be obtained; in addition, the customized capacitance calibration ball is matched with the touch pad, and can be used as a standard workpiece auxiliary robot for testing various kinds of precision.

Drawings

Fig. 1 is a schematic structural diagram of the device for calibrating the multi-robot cooperative working coordinate system in the invention.

FIG. 2 is a schematic diagram of the present invention for calibrating a tool coordinate system by a four-point method.

Fig. 3 is a schematic diagram of the calibration of two robot base coordinate systems per group in the present invention.

Fig. 4 is a schematic diagram of the transformation of the user coordinates in the present invention.

Fig. 5 is a schematic diagram of the present invention applied to a plurality of robots simultaneously welding the same large workpiece at different positions.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The following disclosure provides many different embodiments or examples for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize applications of other processes and/or uses of other materials.

As shown in fig. 1 to 5, an apparatus for calibrating a multi-robot cooperative working coordinate system includes a calibration tool head, a suction calibration target 6, and a calibration plate mechanism:

the calibration tool head comprises a calibration ball 5 which is arranged at a flange plate at the tail end of the robot through a connecting structure;

the suction calibration target 6 is in multi-point attraction with the calibration ball to determine a tool coordinate system based on the robot execution tail end;

the calibration plate mechanism comprises a touch screen 7, and the touch screen 7 and the calibration ball 5 are matched through a multi-point method to determine a user coordinate system of the robot-based execution tail end on the touch screen 7;

under the condition that the robot base is fixed, acquiring a base coordinate system of the robot, and finally obtaining the conversion relation between the base coordinate system of the robot and a user coordinate system by calculating the conversion relation between the base coordinate system of the same robot and a tool coordinate system and the conversion relation between the tool coordinate system and the user coordinate system; the respective user coordinate systems of different robots are established on the touch screen 7, and the conversion relation between the base coordinate systems of different robots is finally obtained, so that the calibration of the multi-robot cooperative work coordinate system is completed.

In the technical scheme, the suction calibration target 6 needs to be fixed on a working table top or a stable position when in use, so that the calibration accuracy is ensured.

In some embodiments, a concave groove 61 matching with the spherical surface of the calibration ball 5 is provided at the top end of the suction calibration target 6, and the spherical surface of the calibration ball 5 is required to be completely fit with the concave groove 61 of the suction calibration target 6 during calibration.

In some embodiments, different means may be adopted according to actual needs to attract the calibration ball 5 and the suction calibration target 6 to each other, so that the spherical surface of the calibration ball 5 and the concave groove 61 of the suction calibration target 6 are completely attached: (1) the calibration ball 5 and the suction calibration target 6 are mutually attracted in a magnetic way: the magnets are arranged in the attraction force calibration target 6, the magnetic material is arranged in the calibration ball 5, when the robot drives the calibration ball 5 to be close to the attraction force calibration target 6 under the condition that the posture is not changed, the attraction force calibration target 6 and the calibration ball 5 are mutually attracted, and the spherical surface of the calibration ball 5 is completely attached to the concave groove 61 of the attraction force calibration target 6. Of course, the magnet can be arranged in the calibration ball 5, and the magnetic material can be arranged in the attraction calibration target 6 to realize magnetic attraction. (2) The calibration ball 5 and the suction calibration target 6 are mutually attracted by adopting a vacuum adsorption mode: the concave groove 61 is provided with a plurality of air holes, the air holes are connected with a vacuumizing device, when the robot drives the calibration ball 5 to be close to the suction calibration target 6 under the condition that the posture is not changed, the vacuumizing device vacuumizes to enable the concave groove 61 to form negative pressure, the calibration ball 5 is sucked into the concave groove 61, and the spherical surface of the calibration ball 5 is completely attached to the concave groove 61 of the suction calibration target 6. Of course, the calibration ball 5 may be provided with an air hole, and the air hole is connected with a vacuum pumping device to realize vacuum absorption.

In some embodiments, in order to eliminate human factors and ensure that the spherical surface of the calibration ball 5 completely fits the concave groove 61 of the suction calibration target 6 during calibration, the calibration tool head further comprises a deformation sensor 3, and in addition, the calibration ball 5 adopts an active capacitance calibration ball and needs to be powered by a power supply; the active capacitance calibration ball is connected with the deformation sensor 3: the deformation sensor 3 is pre-zeroed, then the robot drives the calibration ball 5 to be close to the suction calibration target 6 under the condition that the posture is kept unchanged, once the calibration ball 5 receives suction, the numerical value of the deformation sensor 3 is changed, the position of the execution tail end of the robot is adjusted until the deformation sensor 3 returns to zero again, and at the moment, the spherical surface of the calibration ball 5 is completely attached to the concave groove 61 of the suction calibration target 6.

In the technical scheme, as shown in fig. 2, the zero-set deformation sensor 3 is close to the suction calibration target 6 along with the calibration ball 5 with unchanged posture, and when the calibration ball 5 receives suction, the value of the deformation sensor 3 is changed, so that the calibration ball 5 is attached to the suction calibration target 6 by controlling the movement of the robot, and the value of the deformation sensor 3 returns to zero again to serve as a judgment basis for complete attachment. Because of the dead weight, the values collected by the deformation sensor 3 are different inevitably when the calibration ball 5 is in different postures, so that zero setting is carried out only under the influence of the dead weight and the environment after the posture is changed when the calibration is carried out.

In some embodiments, the calibration ball 5 may be powered by a built-in battery or by connecting to a power source through a communication line, and this technical solution is not specified in detail.

In order to facilitate control of the movement of the robot during calibration to achieve a fast re-zeroing of the deformation sensor 3, the following settings may be provided: (1) the deformation sensor 3 is connected with the control moving module, the control moving module is connected with the robot, the deformation sensor 3 feeds back real-time collected numerical values to the control moving module, and the control moving module guides the robot to move according to the fed-back numerical values, so that the spherical surface of the calibration ball 5 is quickly and completely attached to the concave groove 61 of the suction calibration target 6, and the calibration process is simplified. (2) Still including being used for realizing the LED pilot lamp and the zero setting button of the suggestion of lighting according to the deflection that deformation sensor 3 gathered, the LED pilot lamp is connected with deformation sensor 3, and the zero setting button is connected with deformation sensor 3: if a circle of LED lamps is arranged to be used as an indication of the deformation direction of the calibration ball 5, and red, yellow and green are used as signals of the deformation sensor 3 from large to small; the zero setting button is used for taking deformation force borne under the current posture as a zero point, if a calibration tool head is installed at the tail end of the robot, the posture of the calibration tool head is adjusted to be finished (namely, the situation that the subsequent calibration tool head only carries out space movement and does not carry out any rotation action is ensured), at the moment, the deformation sensor 3 has data due to the weight of the calibration tool head, and the data of the deformation sensor 3 at the moment are taken as a reference point (namely, the zero point) by pressing the zero setting button because the posture can not change.

In some embodiments, in order to facilitate installation, the calibration tool head further includes a communication connector 2, a tool connecting flange 1 and a calibration tool connecting rod 4, the deformation sensor 3 is disposed on the tool connecting flange 1, the communication connector 2 is disposed on the tool connecting flange 1, the deformation sensor 3 is connected to the calibration ball 5 through the calibration tool connecting rod 4, the tool connecting flange 1 is installed in cooperation with a terminal flange of the robot, the tool connecting flange 1, the communication connector 2, the deformation sensor 3, the calibration tool connecting rod 4 and the active capacitance calibration ball 5 are assembled into the calibration tool head (where the tool connecting flange 1 and the calibration tool connecting rod 4 serve as a connecting structure to enable the calibration ball 5 to be installed at the terminal flange of the robot), the calibration tool head is assembled at the terminal of the robot, and the deformation sensor 3 is installed at the terminal flange of the robot through the communication connector 2, The communication cable 9 is connected with the computer 10, so that the computer 10 can acquire the current deformation of the deformation sensor 3 in real time. Of course, the calibration tool head is not limited to the above-mentioned mounting structure, as long as the mounting of the structure and the realization of the effect can be facilitated, and for example, the deformation sensor 3 may be mounted between the calibration tool link 4 and the calibration ball 5.

In some embodiments, the touch screen 7 is a high hardness glass high PPI touch screen, which uses a capacitive sensing technology, and can obtain a high-precision contact position by matching with a signal of an active capacitance calibration ball, which is much faster and more accurate than a visual judgment. The high-hardness glass of the high-hardness glass high-PPI touch screen ensures the surface smoothness and the durability of the screen and meets the requirement of frequent contact use. PPI (PixelsPerInch) represents the number of pixels per inch, the high-hardness glass high-PPI touch screen can achieve high PPI (namely the side length of one pixel point is less than or equal to 0.05mm), and standard patterns are displayed through the high resolution for precision judgment.

In practical use, the high-hardness glass high-PPI touch screen needs to be fixed during calibration, and various fixing structures can be adopted to fix the high-hardness glass high-PPI touch screen. In this embodiment, the high-hardness glass high-PPI touch screen is fixed by a calibration bracket 8, and the calibration bracket 8 is of a camera triangular fixing bracket structure.

In the technical scheme, the calibration support 8 and the touch screen 7 form a calibration plate device, the touch screen 7 is fixed through the calibration support 8 or other fixed tools, the deformation sensor 3 is pre-zeroed, the calibration ball 5 with the unchanged posture is driven by the tail end of the mobile robot to touch the touch screen 7, after the data sensed by the deformation sensor 3 is changed, the calibration ball 5 with the unchanged posture is driven by the tail end of the mobile robot to slowly move on the touch screen 7 until the data of the deformation sensor 3 returns to zero and the touch screen 7 can measure the judgment basis that the touch point is the acquired calibration point.

A calibration method for calibrating a device for calibrating a multi-robot cooperative working coordinate system comprises the following steps:

s1: determining a base coordinate system of each robot: fixing the robots to be calibrated according to the cooperation relationship, ensuring that the robot base coordinate system does not displace any more in the calibration process, and obtaining the base coordinate system of each robot, and marking as { B };

s2: installing a calibration tool head on the tail end of each robot;

s3: fixing the suction calibration target 6, pre-zeroing the deformation sensor 3, then enabling the robot to drive the calibration ball 5 to be close to the suction calibration target 6 under the condition that the posture is kept unchanged, enabling the numerical value of the deformation sensor 3 to be changed (not zero), controlling the position of the execution tail end of the robot until the deformation sensor 3 returns to zero again, and completely attaching the spherical surface of the calibration ball 5 to the concave groove 61 of the suction calibration target 6 to obtain the position information of the current calibration ball 5;

s4: repeating the step S3 to a set number of times, changing the posture of the robot once every time the step is executed, and determining a tool coordinate system of the robot by a multipoint method, wherein the tool coordinate system is marked as { T };

s5: repeatedly performing S3 to S4 by the number of robots to determine tool coordinate systems of all the robots;

s6: grouping all the robots into a group according to two adjacent robots;

s7: fixing a calibration plate device between a group of two robots;

s8: pre-zeroing the deformation sensor 3, driving the calibration ball 5 to touch on the touch screen 7 by the robot under the condition that the posture is kept unchanged, and moving the robot to execute the calibration ball 5 of which the tail end drives the posture is unchanged to slowly move on the touch screen 7 after the data sensed by the deformation sensor 3 is changed until the data of the deformation sensor 3 returns to zero and the touch screen 7 can measure the position data of a touch point;

s9: repeatedly executing the step S8 for a set number of times, changing the position of the calibration ball 5 on the touch screen 7 on the premise of not changing the posture of the robot once execution, and executing the preset distance value between the positions twice to determine the user coordinate system of the robot;

s10: performing S8 to S9 on both the two robots of the same group to determine respective user coordinate systems of the two robots of the same group, and acquiring a relationship of the user coordinate systems between the two robots of the same group;

s11: establishing a relation of a base coordinate system between two robots in the same group: calculating the conversion relation between the base coordinate system and the tool coordinate system of the same robot and the conversion relation between the tool coordinate system and the user coordinate system, and finally obtaining the conversion relation between the base coordinate system and the user coordinate system of the robot; finally establishing the relation of a base coordinate system between the two robots in the same group according to the relation of the user coordinate systems between the two robots in the same group;

s12: and repeatedly executing S7 to S11 until all the robots are linked by the base coordinate system.

In some embodiments, the tool coordinate system of each robot may be determined by a four-point method, i.e., in S4, S3 to 4 times are repeatedly performed.

In some embodiments, the user coordinate system of each robot in each group of robots may be determined by a three-point method, i.e., in S9, S8 to 3 times are repeatedly performed.

In some embodiments, in S9, each time the robot gesture is changed, the position of the calibration sphere 5 on the touch screen 7 is changed, and a preset distance between the two executed positions is determined to determine the user coordinate system of the robot, where the preset distance between the two executed positions is generally greater than 10 cm.

Wherein, the relation of a base coordinate system between two robots in the same group is established, and the specific calculation process is as follows:

(1) in S1, the matrix of the terminal flange plate coordinate system based on the base coordinate system of the robot is obtained by reading the current pose value of the robot^BM_E；

(2) In S2-S4, the matrix of the coordinate system of the calibration tool based on the end flange of the robot is obtained as^EM_T；

(3) Obtaining a calibration tool coordinate system matrix based on the robot base coordinate system through (1) and (2) as^BM_E·^EM_T＝^BM_T；

(4) From (1) to (3), and S7 to S11, the user coordinate system matrix based on the robot base coordinate system is finally obtained as^BM_U：

In S11, establishing a relationship between the two robots in the same group in the user coordinate system includes the following steps: when a user coordinate system of the robot on the touch screen 7 is established, a calibration board-based device is used for executing tail end through acquiring the robotThree point parameters of an origin coordinate system { O } (namely, an origin coordinate system of the touch screen 7) (the user coordinate system of the robot is determined by a three-point method), the three point parameters are transmitted to a computer through a communication cable of a calibration board device, and the computer is enabled to calculate the position relation of each robot user coordinate system { U } based on the origin coordinate system { O } of the calibration board device, as shown in FIG. 4, the three point parameters are respectively P1(x1, y1 and z1), P2(x2, y2, z2) and P3(x3, y 3 and z3) coordinate values are all based on the origin coordinate system { O } on the calibration board device, and as the touch screen 7 is a plane, the z values are all 0, the relative relation between the user coordinate system { U } and the origin coordinate system { O } of the calibration board device is only different by theta DEG, and the position deviation is equal toThis gives:

matrix of user coordinate system { U } and calibration board apparatus origin coordinate system { O }

The relation of two robot base coordinate systems can be established by the formula and the steps through a calibration plate device

^BM_O＝^BM_U*(^OM_U)^-1

And inverting the two sides to obtain a coordinate system based on the origin of the calibration plate:

^OM_B＝^OM_U*(^BM_U)^-1

therefore, as shown in fig. 2, the following relationship is obtained after each two robots are cooperatively calibrated:

^B1M_B2＝^B1M_U1*^U1M_U2*^U2M_B2

^B1M_B2＝^B1M_U1*^U1M_U2*(^B2M_U2)^-1

wherein the content of the first and second substances,^U1M_U2＝(^OM_U1)^-1*^OM_U2

^B1M_U1and^B2M_U2the relation between the two robot base coordinate systems can be calculated as known.

The method can calculate the mutual relation of the robot groups by mutually calibrating every two robots^B1M_B2、^B2M_B3···^Bi-1M_Bi(ii) a Then calculates the relation between any two robots^BmM_Bn。