WO2020237407A1 - Method and system for self-calibrating robot kinematic parameter, and storage device - Google Patents

Method and system for self-calibrating robot kinematic parameter, and storage device Download PDF

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WO2020237407A1
WO2020237407A1 PCT/CN2019/088251 CN2019088251W WO2020237407A1 WO 2020237407 A1 WO2020237407 A1 WO 2020237407A1 CN 2019088251 W CN2019088251 W CN 2019088251W WO 2020237407 A1 WO2020237407 A1 WO 2020237407A1
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robot
calibration
error
standard workpiece
actual
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PCT/CN2019/088251
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French (fr)
Chinese (zh)
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李康宁
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深圳配天智能技术研究院有限公司
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Priority to PCT/CN2019/088251 priority Critical patent/WO2020237407A1/en
Publication of WO2020237407A1 publication Critical patent/WO2020237407A1/en

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B25HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25JMANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J9/00Programme-controlled manipulators
    • B25J9/16Programme controls
    • B25J9/1628Programme controls characterised by the control loop
    • B25J9/1653Programme controls characterised by the control loop parameters identification, estimation, stiffness, accuracy, error analysis
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B25HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25JMANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J19/00Accessories fitted to manipulators, e.g. for monitoring, for viewing; Safety devices combined with or specially adapted for use in connection with manipulators
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B25HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25JMANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J9/00Programme-controlled manipulators
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B25HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25JMANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J9/00Programme-controlled manipulators
    • B25J9/16Programme controls
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B25HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25JMANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J9/00Programme-controlled manipulators
    • B25J9/16Programme controls
    • B25J9/1656Programme controls characterised by programming, planning systems for manipulators
    • B25J9/1661Programme controls characterised by programming, planning systems for manipulators characterised by task planning, object-oriented languages

Abstract

A method for self-calibrating a robot kinematic parameter, comprising: a calibrated robot enables an end effector to contact with the surface of a standard workpiece for multiple times, and records angles of axes of the calibrated robot during each contact, the standard workpiece being mounted on a flange of a reference robot; the reference robot changes the attitude of the standard workpiece; the calibrated robot repeatedly executes the step of enabling the end effector to contact with the surface of the standard workpiece for multiple times, and recording the angles of axes of the calibrated robot during each contact so as to obtain a plurality of groups of axis angle values of the calibrated robot; and obtain the actual kinematic parameter of the calibrated robot according to the plurality of groups of axis angle values, the nominal kinematic parameter of the calibrated robot, and the actual diameter of the standard workpiece. The method can improve the efficiency, achieve automatic calibration, and make it easy to achieve batch calibration. The present invention also relates to a system for executing the method, and a storage device for storing a program file of the method.

Description

机器人运动学参数自标定方法、系统及存储装置Robot kinematics parameter self-calibration method, system and storage device 【技术领域】【Technical Field】
本申请涉及机器人领域,尤其是涉及一种机器人运动学参数自标定方法、系统及存储装置。This application relates to the field of robotics, and in particular to a method, system and storage device for self-calibration of robot kinematics parameters.
【背景技术】【Background technique】
机器人的运动精度对于工业机器人在生产中的应用可靠性起着至关重要的作用。机器人各连杆的几何参数(DH参数)误差是造成机器人系统误差的主要环节,其主要是由于制造和安装过程中产生的连杆实际几何参数与理论参数值之间的偏差造成的。The motion accuracy of the robot plays a vital role in the application reliability of industrial robots in production. The geometric parameter (DH parameter) error of each connecting rod of the robot is the main link that causes the robot system error, which is mainly caused by the deviation between the actual geometric parameters of the connecting rod and the theoretical parameter value during the manufacturing and installation process.
常用的机器人DH参数标定方法有两种:一种是利用激光跟踪仪或三坐标测量机等外部测量设备,测量被标定机器人TCP点在各测量点的位姿,根据实际测量位姿和使用机器人名义DH参数正解得到的理论测量位姿的误差,辨识DH参数的误差。但是,由于激光跟踪仪等大型高精度测量设备具有成本高、体积大的特点,所以难以满足机器人批量生产时需要为提高效率多台同时进行标定的需求。There are two commonly used robot DH parameter calibration methods: one is to use external measurement equipment such as laser tracker or three-coordinate measuring machine to measure the pose of the calibrated robot TCP point at each measurement point, according to the actual measurement of the pose and the use of the robot The error of the theoretical measurement pose obtained by the positive solution of the nominal DH parameter is used to identify the error of the DH parameter. However, due to the characteristics of high cost and large volume of large-scale high-precision measurement equipment such as laser trackers, it is difficult to meet the demand for simultaneous calibration of multiple robots to improve efficiency during mass production of robots.
另一种方法是使用标准工件的自标定方法,机器人法兰上安装机床测头,特制标定标准工件为三个固定在底座上的标准球,标定过程中,控制机器人,使机床测头碰触各标准球的表面多次,改变标准球工件底座的位姿,重复以上测量过程,根据测量得到的轴位置和运动学正解计算出名义DH参数下标准球表面测量点的笛卡尔位置坐标,并通过球面拟合拟合出多组球心,并计算理论球心的距离。利用计算出的理论球心距离和实际球心距离的误差标定出DH参数。然而,带有三个标准球的订制工件作为自标定中的固定物理约束,需要高加工精度的标准工件,且需要另配调整工件位姿的方案,所以增加了成本和降低了自动化程度。Another method is to use the self-calibration method of standard workpieces. The machine tool probe is installed on the robot flange, and the special calibration standard workpieces are three standard balls fixed on the base. During the calibration process, the robot is controlled so that the machine tool probe touches The surface of each standard ball is changed many times, the pose of the standard ball workpiece base is repeated, the above measurement process is repeated, and the Cartesian position coordinate of the measurement point on the surface of the standard ball under the nominal DH parameter is calculated according to the measured shaft position and the positive kinematics solution, and Fit multiple sets of sphere centers through spherical fitting, and calculate the distance of theoretical sphere centers. The DH parameters are calibrated using the calculated error between the theoretical sphere center distance and the actual sphere center distance. However, a custom-made workpiece with three standard balls is used as a fixed physical constraint in self-calibration, and a standard workpiece with high machining accuracy is required, and an additional solution for adjusting the pose of the workpiece is required, which increases the cost and reduces the degree of automation.
【发明内容】[Content of the invention]
本申请提出一种机器人运动学参数自标定方法、系统及存储装置,能够降低成本且能够实现自动化标定,易于实现批量标定。This application proposes a method, system and storage device for self-calibration of robot kinematics parameters, which can reduce costs, can realize automatic calibration, and is easy to realize batch calibration.
为了解决以上问题,本申请提出了一种机器人运动学参数自标定方法,包括:标定机器人将末端执行器多次接触标准工件表面,并记录每次接触所述标定机器人各轴的角度,其中所述标准工件安装于参考机器人的法兰;所述参考机器人改变所述标准工件的位姿,所述标定机器人重复执行以所述末端执行器多次接触标准工件表面,并记录每次接触所述标定机器人各轴的角度的步骤,以获取所述标定机器人的多组轴角度值;利用所述多组轴角度值、所述标定机器人的名义运动学参数以及所述标准工件的实际半径,得到所述标定机器人的实际运动学参数。In order to solve the above problems, this application proposes a robot kinematic parameter self-calibration method, which includes: the calibration robot contacts the end effector multiple times to the surface of the standard workpiece, and records the angle of each axis of the calibration robot each time. The standard workpiece is installed on the flange of a reference robot; the reference robot changes the pose of the standard workpiece, the calibration robot repeatedly executes the end effector contacting the surface of the standard workpiece multiple times, and records each contact The step of calibrating the angles of each axis of the robot to obtain multiple sets of axis angle values of the calibration robot; using the multiple sets of axis angle values, the nominal kinematic parameters of the calibration robot, and the actual radius of the standard workpiece to obtain The actual kinematics parameters of the calibration robot.
为了解决以上问题,本申请还提出了一种机器人运动学参数自标定系统,包括:标定机器人和参考机器人;所述标定机器人的法兰安装有末端执行器,所述参考机器人的法兰安装有标准工件;所述参考机器人用于改变所述标准工件的位姿;所述标定机器人用于执行指令以实现如上所述的机器人运动学参数自标定方法。In order to solve the above problems, this application also proposes a robot kinematic parameter self-calibration system, including: a calibration robot and a reference robot; the flange of the calibration robot is equipped with an end effector, and the flange of the reference robot is equipped with Standard workpiece; the reference robot is used to change the pose of the standard workpiece; the calibration robot is used to execute instructions to implement the above-mentioned robot kinematic parameter self-calibration method.
为了解决以上问题,本申请又提出了一种存储装置,内部存储有程序文件,其特征在于,所述程序文件被执行以实现如上所述的机器人运动学参数自标定方法。In order to solve the above problems, this application also proposes a storage device with a program file stored inside, which is characterized in that the program file is executed to realize the above-mentioned robot kinematic parameter self-calibration method.
区别于现有技术,本申请的实施例中,利用法兰上安装有标准工件的参考机器人辅助标定,标定工具简单,效率高,且在标定时,只需一次输入标定机器人和参考机器人的运动指令,标定过程中标定机器人和参考机器人即可以自动运动和计算,无需人工干预,所以标定自动化程度高,适用于机器人生产过程中大批量的标定需求。Different from the prior art, in the embodiment of the present application, the reference robot with standard workpieces mounted on the flange is used to assist the calibration. The calibration tool is simple and efficient. During the calibration, only the movement of the calibration robot and the reference robot needs to be input once. In the process of calibration, the calibration robot and the reference robot can automatically move and calculate without manual intervention, so the calibration has a high degree of automation, which is suitable for large-scale calibration requirements in the robot production process.
【附图说明】【Explanation of drawings】
图1是本申请机器人运动学参数自标定方法第一实施例的流程示意图;FIG. 1 is a schematic flowchart of a first embodiment of a method for self-calibration of robot kinematics parameters according to the present application;
图2是图1所示方法的执行场景示意图;Fig. 2 is a schematic diagram of an execution scenario of the method shown in Fig. 1;
图3是图1中步骤S11和S12的具体流程示意图;FIG. 3 is a schematic diagram of a specific flow of steps S11 and S12 in FIG. 1;
图4是图1中步骤S13的具体流程示意图;FIG. 4 is a schematic diagram of a specific flow of step S13 in FIG. 1;
图5是本申请机器人运动学参数自标定方法第二实施例的流程示意图;FIG. 5 is a schematic flowchart of a second embodiment of a method for self-calibration of robot kinematic parameters according to the present application;
图6是图5中各步骤的具体流程示意图;FIG. 6 is a schematic diagram of the specific flow of each step in FIG. 5;
图7是本申请机器人运动学参数自标定系统第一实施例的结构示意图;Fig. 7 is a schematic structural diagram of a first embodiment of a robot kinematic parameter self-calibration system according to the present application;
图8是本申请机器人运动学参数自标定系统第二实施例的结构示意图;8 is a schematic structural diagram of a second embodiment of the robot kinematic parameter self-calibration system according to the present application;
图9是本申请存储装置一实施例的结构示意图。FIG. 9 is a schematic structural diagram of an embodiment of a storage device of the present application.
【具体实施方式】【Detailed ways】
下面结合附图和实施例对本申请进行详细说明。The application will be described in detail below with reference to the drawings and embodiments.
如图1所示,本申请机器人运动学参数自标定方法第一实施例包括:As shown in Fig. 1, the first embodiment of the robot kinematic parameter self-calibration method of the present application includes:
S11:标定机器人将末端执行器多次接触标准工件表面,并记录每次接触时标定机器人各轴的角度。S11: The calibration robot touches the end effector to the surface of the standard workpiece multiple times, and records the angle of each axis of the calibration robot during each contact.
其中,该末端执行器安装于标定机器人的法兰,标准工件安装于参考机器人的法兰。机器人各轴的角度是指机器人各关节以各关节轴线为转轴转动的角度。Among them, the end effector is installed on the flange of the calibration robot, and the standard workpiece is installed on the flange of the reference robot. The angle of each axis of the robot refers to the angle of rotation of each joint of the robot with each joint axis as the rotation axis.
结合图1和图2所示,在一个应用例中,标定机器人A的法兰安装有末端执行器10,参考机器人B的法兰安装有标准工件20,为了使得标定机器人A可以接触到标准工件20表面的不同位置,该标定机器人A和参考机器人B相对设置,从而使得标定机器人A和参考机器人B的灵巧工作空间有较大的重合,也就是使得二者机械臂的移动空间重合度较大,例如重合度达到至少50%。其中该末端执行器10可以是如图2中的机床侧头,为了满足标定精度的要求,机床测头可以选用重复精度1um及以下的型号,标准工件20可以采用标准球工件,该标准球工件需要有较高的球面度和表面光滑度,例如三坐标检具标准球。As shown in Figure 1 and Figure 2, in an application example, the flange of the calibration robot A is equipped with an end effector 10, and the flange of the reference robot B is equipped with a standard workpiece 20, so that the calibration robot A can touch the standard workpiece At different positions on the surface of 20, the calibration robot A and the reference robot B are arranged relative to each other, so that the smart working spaces of the calibration robot A and the reference robot B have a larger overlap, which means that the moving spaces of the two manipulators overlap more. , For example, the coincidence degree reaches at least 50%. The end effector 10 can be the side head of the machine tool as shown in Fig. 2. In order to meet the requirements of calibration accuracy, the machine tool probe can choose a model with a repeatability of 1um and below, and the standard workpiece 20 can be a standard ball workpiece. Need to have a higher degree of sphericity and surface smoothness, such as the three-coordinate gauge standard ball.
标定时,参考机器人B控制其机械臂,使得标准工件20的位姿为C i,标定机器人A控制其机械臂,可以使得末端执行器10多次接触标准工件20的表面,且每次接触均记录标定机器人A各轴的角度。其中,由标定机器人A自身的控制器(图未示)在末端执行器10触碰标准工件20的表面后记录该标定机器人A各轴的角度,当然也可以由标定机器人A将其各轴的角度传输给外部设备或生成相关文件进行存储记录。 During calibration, the reference B controlled robot manipulator, so that the position and orientation of the workpiece 20 is a standard C i, which control the calibration of the robot manipulator A, the end effector 10 may be such that multiple contact standard surface 20 of the workpiece, and are in contact with each Record the angle of each axis of the calibration robot A. Among them, the calibration robot A's own controller (not shown) records the angles of each axis of the calibration robot A after the end effector 10 touches the surface of the standard workpiece 20. Of course, the calibration robot A can also control the axis The angle is transmitted to an external device or related files are generated for storage and recording.
可选地,如图3所示,步骤S11具体包括:Optionally, as shown in FIG. 3, step S11 specifically includes:
S111:标定机器人的末端执行器以不同姿态接触标准工件表面的不同位置m次,并记录每次接触标定机器人各轴的角度。S111: The end effector of the calibration robot touches different positions on the surface of the standard workpiece m times in different postures, and records the angle of each axis of the calibration robot each time it touches.
本实施例中,标定机器人为链式机器人。链式机器人可以由关节-连杆-关节-连杆-……-连杆-末端执行器这样的结构式来描述。DH参数(Denavit–Hartenberg parameters)是由Denavit和Hartenberg在1955年提出的表达相邻关节及其之间的连杆的位置角度关系的机械臂数学模型和坐标系确定系统的四个参数。In this embodiment, the calibration robot is a chain robot. The chain robot can be described by the structure of joint-link-joint-link -...-link-end effector. DH parameters (Denavit–Hartenberg parameters) are the four parameters of the mechanical arm mathematical model and coordinate system that are proposed by Denavit and Hartenberg in 1955 to express the position and angle relationship of adjacent joints and the links between them.
由于链式机器人每个连杆对应的DH参数的个数为4,为了较为准确地标定机器人的运动学参数DH参数,标定机器人A接触同一位姿的标准工件20的次数m应大于4,例如预设m=8。Since the number of DH parameters corresponding to each link of the chain robot is 4, in order to calibrate the kinematic parameters DH parameters of the robot more accurately, the number of times m that the calibration robot A contacts the standard workpiece 20 in the same pose should be greater than 4, for example Default m=8.
具体地,结合图2和图3所示,为了提高标定的准确度,标定机器人A控制末端执行器10接触标准工件20时,可以采用不同的姿态接触标准工件20表面的不同位置,且每次接触时,记录标定机器人A各轴的角度q ij。例如,末端执行器10每次接触标准工件20表面的位置均不同,且均是以不同位姿进行接触,或者部分次数采用不同位姿接触标准工件20表面的相同位置。 Specifically, in conjunction with Figures 2 and 3, in order to improve the accuracy of calibration, when the calibration robot A controls the end effector 10 to contact the standard workpiece 20, it can use different postures to contact different positions on the surface of the standard workpiece 20, and each time During contact, record the angle q ij of each axis of the calibration robot A. For example, each time the end effector 10 touches the surface of the standard workpiece 20, the position is different, and the contact is made in a different pose, or the same position on the surface of the standard workpiece 20 is contacted with different poses some times.
S12:参考机器人改变标准工件的位姿,标定机器人重复执行步骤S11,以获取标定机器人的多组轴角度值。S12: Refer to the robot to change the pose of the standard workpiece, and the calibration robot repeats step S11 to obtain multiple sets of axis angle values of the calibration robot.
具体地,为了获取更充分的数据,参考机器人可以多次改变标准工件的位姿,每次改变位姿后,标定机器人可以重复执行上述步骤S11,从而可以得到标 准工件的不同位姿对应的标定机器人的各轴的角度,其中标准工件的同一位姿下记录得到的标定机器人的各轴的角度形成一组轴角度值,则可以获取标定机器人的多组轴角度值,以便后续计算标定机器人的实际运动学参数,即实际DH参数。Specifically, in order to obtain more sufficient data, the reference robot can change the pose of the standard workpiece multiple times. After each pose change, the calibration robot can repeat the above step S11, so that the calibration corresponding to the different poses of the standard workpiece can be obtained. The angle of each axis of the robot. The angle of each axis of the calibration robot recorded under the same pose of the standard workpiece forms a set of axis angle values, and then multiple sets of axis angle values of the calibration robot can be obtained for subsequent calculations of the calibration robot The actual kinematics parameters are actual DH parameters.
结合图2所示,该参考机器人B可以控制其机械臂移动,从而改变标准工件20的位姿,例如从位姿C 1改变为位姿C 2,然后标定机器人A可以重复执行步骤S11,即控制末端执行器10多次接触标准工件20表面的不同位置,进而可以得到标准工件的位姿C 1和位姿C 2分别对应的两组标定机器人的轴角度值。 As shown in FIG. 2, the reference robot B can control the movement of its manipulator to change the pose of the standard workpiece 20, for example, from the pose C 1 to the pose C 2 , and then the calibration robot A can repeat step S11, namely The end effector 10 is controlled to contact different positions on the surface of the standard workpiece 20 for multiple times, and then two sets of axis angle values of the calibration robot corresponding to the pose C 1 and the pose C 2 of the standard workpiece can be obtained.
可选地,如图3所示,步骤S12包括:Optionally, as shown in FIG. 3, step S12 includes:
S121:判断参考机器人改变标准工件的位姿的次数是否大于(n-1)。S121: Determine whether the number of times the reference robot changes the pose of the standard workpiece is greater than (n-1).
其中,为了充分获取标定数据,根据标定机器人的轴数和每个轴的DH参数个数,选取n的具体取值。例如,当标定机器人是六轴串联机器人时,n的取值应大于20,如n=60。Among them, in order to fully obtain the calibration data, the specific value of n is selected according to the number of axes of the calibration robot and the number of DH parameters of each axis. For example, when the calibration robot is a six-axis serial robot, the value of n should be greater than 20, such as n=60.
若判断结果为不大于,则执行如下步骤S122,否则执行步骤S124。If the judgment result is not greater than, the following step S122 is executed, otherwise, the step S124 is executed.
S122:改变标准工件的位姿,并返回执行步骤S111。S122: Change the pose of the standard workpiece, and return to step S111.
S124:根据获取的n*m组标定机器人各轴的角度,继续执行步骤S13。S124: Calibrate the angles of each axis of the robot according to the acquired n*m groups, and continue to perform step S13.
具体地,在一个应用例中,参考机器人使用一个计数装置,当其每次控制机械臂改变标准工件的位姿时,该计数装置计数一次,则该参考机器人每次改变标准工件的位姿之前,可以先判断参考机器人已经改变标准工件的位姿的次数是否达到要求,即已经改变次数是否大于(n-1)(如是否大于50),也就是判断是否已经完成标准工件n个位姿下测量得到多组标定机器人各轴的角度。若改变次数小于(n-1),此时可以继续执行步骤S122,改变标准工件的位姿,并返回执行步骤S111,获取该改变后的标准工件位姿对应的标定机器人多次接触标准工件表面的各轴的角度。若改变次数已经大于n,即标准工件的位姿的改变次数已经达到要求,此时标定数据已经充分获取,可以继续执行后续步骤S13。Specifically, in an application example, the reference robot uses a counting device, and every time it controls the manipulator to change the pose of the standard workpiece, the counting device counts once, then the reference robot changes the pose of the standard workpiece every time. , You can first determine whether the number of times the reference robot has changed the pose of the standard workpiece meets the requirements, that is, whether the number of changes has been greater than (n-1) (such as whether it is greater than 50), that is, whether the standard workpiece has been completed in n poses Measure multiple sets of angles of each axis of the calibration robot. If the number of changes is less than (n-1), you can continue to perform step S122 at this time to change the pose of the standard workpiece, and return to step S111 to obtain the calibration robot corresponding to the changed pose of the standard workpiece. The angle of each axis. If the number of changes has been greater than n, that is, the number of changes in the pose of the standard workpiece has reached the requirement, and the calibration data has been fully obtained at this time, and the subsequent step S13 can be continued.
S13:利用该多组轴角度值、标定机器人的名义运动学参数以及标准工件的 实际半径,计算标定机器人的实际运动学参数。S13: Calculate the actual kinematics parameters of the calibration robot by using the multiple sets of axis angle values, the nominal kinematics parameters of the calibration robot and the actual radius of the standard workpiece.
其中,标准工件采用标准球工件,其实际半径可以预先获取,该标定机器人的名义运动学参数通常出厂时以预先设定,也可以预先获取。Among them, the standard workpiece is a standard spherical workpiece, the actual radius of which can be obtained in advance, and the nominal kinematics parameters of the calibration robot are usually preset at the factory or can be obtained in advance.
具体地,利用机器人运动学正解和逆解,采用DH建模方法,可以预先建立该多组轴角度值、标定机器人的名义运动学参数、标准工件的实际半径以及标定机器人的实际运动学参数的关系方程,从而将已经获取的该多组轴角度值、标定机器人的名义运动学参数以及标准工件的实际半径代入已经建立的关系方程中,求解该关系方程,则可以计算得到标定机器人的实际运动学参数。Specifically, using the forward and inverse solutions of the robot kinematics and the DH modeling method, the multiple sets of axis angle values, the nominal kinematic parameters of the calibration robot, the actual radius of the standard workpiece, and the actual kinematic parameters of the calibration robot can be established in advance. The relationship equation, so that the obtained multiple sets of axis angle values, the nominal kinematic parameters of the calibration robot, and the actual radius of the standard workpiece are substituted into the established relationship equation, and the relationship equation is solved, then the actual motion of the calibration robot can be calculated Learn parameters.
可选地,如图4所示,步骤S13包括:Optionally, as shown in FIG. 4, step S13 includes:
S131:利用该多组轴角度值和标定机器人的名义运动学参数,计算得到每组轴角度值对应的末端执行器与标准工件表面的接触点理论位置。S131: Using the multiple sets of axis angle values and the nominal kinematic parameters of the calibration robot, the theoretical position of the contact point between the end effector and the surface of the standard workpiece corresponding to each set of axis angle values is calculated.
机器人运动学正解指的是已知机器人各轴角度,利用机器人的名义运动学参数(即名义DH参数),求解机器人法兰中心在笛卡尔空间机器人基坐标系下的位姿的过程。当法兰上安装有末端执行器时,只需要对求解出的法兰中心在机器人基坐标系下的位姿进行简单的坐标转换即可以得到末端执行器在机器人基坐标系下的位姿。因此,利用获取的标定机器人的多组轴角度值和名义DH参数,根据机器人运动学正解,可以计算得到每组轴角度值对应的标定机器人末端执行器的工具中心点(即TCP点)在机器人基坐标系下的位姿。由于计算过程中采用的是名义DH参数,因此计算得到的TCP点在机器人基坐标系下的位姿是末端执行器与标准工件表面的接触点在机器人基坐标系下的理论位姿,从该理论位姿可以得到末端执行器与标准工件表面的接触点在机器人基坐标系下的理论位置。The positive solution of robot kinematics refers to the process of using the robot's nominal kinematic parameters (namely the nominal DH parameters) to solve the pose of the robot flange center in the Cartesian space robot base coordinate system with the known angle of each axis of the robot. When the end effector is installed on the flange, it is only necessary to perform a simple coordinate transformation on the calculated pose of the flange center in the robot base coordinate system to obtain the pose of the end effector in the robot base coordinate system. Therefore, by using the obtained multiple sets of axis angle values and nominal DH parameters of the calibration robot, according to the positive kinematics of the robot, the tool center point (ie TCP point) of the end effector of the calibration robot corresponding to each set of axis angle values can be calculated in the robot The pose in the base coordinate system. Since the nominal DH parameters are used in the calculation process, the calculated pose of the TCP point in the robot base coordinate system is the theoretical pose of the contact point between the end effector and the standard workpiece surface in the robot base coordinate system. The theoretical pose can get the theoretical position of the contact point of the end effector and the surface of the standard workpiece in the robot base coordinate system.
具体地,当获取的标定机器人的多组轴角度值包括n个标准工件位姿对应的n*m组标定机器人各轴的角度时,可以根据机器人运动学正解,计算得到n组接触点的理论位置,每个标准工件位姿对应一组接触点的理论位置,每组接触点的理论位置包括m个接触点的理论位置,其中该接触点的理论位置是接触 点在机器人基坐标系下的理论位置。Specifically, when the acquired multiple sets of axis angle values of the calibration robot include n*m sets of calibration robot angles corresponding to n standard workpiece poses, the theory of n sets of contact points can be calculated according to the positive solution of the robot kinematics Position, each standard workpiece pose corresponds to the theoretical position of a group of contact points, the theoretical position of each group of contact points includes the theoretical position of m contact points, where the theoretical position of the contact point is the contact point in the robot base coordinate system Theoretical location.
S132:利用多组接触点理论位置,拟合得到每组接触点理论位置对应的标准工件的拟合半径。S132: Using multiple sets of theoretical positions of contact points, fitting to obtain a fitting radius of the standard workpiece corresponding to each set of theoretical positions of contact points.
具体地,当标准工件是标准球工件时,利用计算得到的多组接触点的理论位置,采用球面拟合算法可以拟合得到每组接触点的理论位置对应的标准工件的拟合半径,一组接触点的理论位置可以拟合得到一个标准工件的拟合半径。Specifically, when the standard workpiece is a standard spherical workpiece, using the calculated theoretical positions of multiple sets of contact points, the spherical fitting algorithm can be used to fit the fitting radius of the standard workpiece corresponding to the theoretical position of each set of contact points. The theoretical position of the group contact point can be fitted to get the fitting radius of a standard workpiece.
S133:根据该拟合半径以及实际半径之间的拟合半径误差计算实际运动学参数。S133: Calculate actual kinematics parameters according to the fitted radius and the fitted radius error between the actual radius.
其中,标准工件的实际半径在选择使用的标准工件后即可以预先得到,利用该拟合半径和实际半径之间的差,则可以得到拟合半径误差。Among them, the actual radius of the standard workpiece can be obtained in advance after the standard workpiece to be used is selected, and the fitting radius error can be obtained by using the difference between the fitted radius and the actual radius.
由于拟合采用的原始数据是接触点的理论位置,而接触点的理论位置是采用名义DH参数计算得到的,因此拟合得到的拟合半径与实际半径之间的拟合误差与DH参数误差之间存在对应关系,利用该对应关系,则可以计算得到该DH参数误差,即实际运动学参数(实际DH参数)与名义运动学参数(名义DH参数)之间的运动学参数误差。然后,由于标定机器人的名义DH参数可以事先得到,利用该名义DH参数叠加该运动学参数误差,则可以得到标定机器人的实际DH参数。Since the original data used in the fitting is the theoretical position of the contact point, and the theoretical position of the contact point is calculated using the nominal DH parameter, the fitting error between the fitted radius and the actual radius obtained by the fitting is the DH parameter error There is a correspondence between them, and by using this correspondence, the DH parameter error can be calculated, that is, the kinematic parameter error between the actual kinematic parameter (actual DH parameter) and the nominal kinematic parameter (nominal DH parameter). Then, since the nominal DH parameters of the calibration robot can be obtained in advance, the actual DH parameters of the calibration robot can be obtained by adding the kinematic parameter error to the nominal DH parameters.
本实施例中,利用法兰上安装有标准工件的参考机器人辅助标定,标定工具简单,效率高,且在标定时,只需一次输入标定机器人和参考机器人的运动指令,标定过程中标定机器人和参考机器人即可以自动运动和计算,无需人工干预,所以标定自动化程度高,适用于机器人生产过程中大批量的标定需求。In this embodiment, a reference robot with a standard workpiece mounted on the flange is used to assist the calibration. The calibration tool is simple and efficient. During calibration, you only need to input the motion instructions of the calibration robot and the reference robot once. During the calibration process, the robot and The reference robot can automatically move and calculate without manual intervention, so the calibration has a high degree of automation, which is suitable for large-scale calibration requirements in the robot production process.
如图5所示,本申请机器人运动学参数自标定方法第二实施例是在本申请机器人运动学参数自标定方法第一实施例的基础上,进一步限定步骤S133之前,包括:As shown in FIG. 5, the second embodiment of the robot kinematic parameter self-calibration method of the present application is based on the first embodiment of the robot kinematic parameter self-calibration method of the present application, and before step S133 is further defined, it includes:
S201:建立接触点的位置误差与运动学参数误差之间的第一线性关系方程。S201: Establish a first linear relationship equation between the position error of the contact point and the kinematic parameter error.
其中,由于接触点的理论位置是利用名义运动学参数计算得到的,因此接 触点的位置误差是由于运动学参数误差导致的,可以建立接触点和位置误差与运动学参数误差之间的第一线性关系方程。Among them, since the theoretical position of the contact point is calculated using the nominal kinematic parameters, the position error of the contact point is caused by the kinematic parameter error. The first difference between the contact point and the position error and the kinematic parameter error can be established. Linear relationship equation.
由于线性关系方程可以采用矩阵等式进行表达,求解矩阵等式即可以方便快捷地求解出线性关系方程的解,因此,如图6所示,步骤S201可以包括:Since the linear relationship equation can be expressed by using a matrix equation, the solution of the linear relationship equation can be obtained conveniently and quickly by solving the matrix equation. Therefore, as shown in FIG. 6, step S201 may include:
S2011:将接触点的理论位置和实际位置的差作为元素,建立接触点的位置的误差矩阵。S2011: Use the difference between the theoretical position and the actual position of the contact point as an element to establish an error matrix of the position of the contact point.
其中,接触点的理论位置是接触点在机器人基坐标系下的理论位置,接触点的实际位置是接触点在机器人基坐标系下的实际位置。Among them, the theoretical position of the contact point is the theoretical position of the contact point in the robot base coordinate system, and the actual position of the contact point is the actual position of the contact point in the robot base coordinate system.
根据机器人的正解P ij=f(q ij,DH n),其中P ij为机器人末端执行器的位置,q ij为机器人各轴的角度,DH n为名义DH参数。利用记录得到的标定机器人多组各轴角度值,可以得到在名义DH参数DH n下,标定机器人的末端执行器与标准工件表面的接触点的理论位置p′ ij。假设接触点的实际位置为p ij,则该接触点的理论位置p′ ij和实际位置p ij的差为Δp ij=p′ ij-p ij,然后,将接触点的理论位置和实际位置的差作为元素,则可以建立接触点的位置的误差矩阵Δp=(Δp 11 … Δp nm) T,其中n为记录标定机器人各轴的角度时采用的标准工件的n个位姿,标准工件的每个位姿对应标定机器人各轴的角度的m个记录位置。 According to the robot's positive solution P ij =f(q ij ,DH n ), where P ij is the position of the end effector of the robot, q ij is the angle of each axis of the robot, and DH n is the nominal DH parameter. Using the recorded multiple sets of angle values of each axis of the calibration robot, the theoretical position p′ ij of the contact point between the end effector of the calibration robot and the surface of the standard workpiece under the nominal DH parameter DH n can be obtained. Assuming that the actual position of the contact point is p ij , the difference between the theoretical position p′ ij of the contact point and the actual position p ij is Δp ij =p′ ij -p ij , and then, the theoretical and actual positions of the contact point Difference as an element, the error matrix of the position of the contact point Δp=(Δp 11 … Δp nm ) T can be established, where n is the n poses of the standard workpiece used when recording the angle of each axis of the calibration robot, and each standard workpiece Each pose corresponds to m recorded positions of the angle of each axis of the calibration robot.
S2012:将名义运动学参数和实际运动学参数的差作为元素,建立运动学参数的误差矩阵。S2012: Use the difference between the nominal kinematics parameter and the actual kinematics parameter as the element to establish the error matrix of the kinematics parameter.
假设实际DH参数为DH a,获取的标定机器人的名义DH参数为DH n,由于机器人的DH参数有多个,因此DH a和DH n均可以采用矩阵方式表示,可以建立标定机器人的运动学参数的误差矩阵ΔDH=DH n-DH aAssuming that the actual DH parameter is DH a , and the nominal DH parameter of the calibration robot obtained is DH n , since there are multiple DH parameters of the robot, both DH a and DH n can be expressed in a matrix, and the kinematic parameters of the calibration robot can be established The error matrix ΔDH=DH n -DH a .
S2013:获取接触点的理论位置关于运动学参数的第一雅格比矩阵。S2013: Obtain the first Jacobian matrix of the theoretical position of the contact point with respect to the kinematic parameters.
具体地,雅各比矩阵是由一阶导数构成的矩阵,则接触点的理论位置关于运动学参数的第一雅格比矩阵J DH可以表示如下: Specifically, the Jacobian matrix is a matrix composed of first-order derivatives, and the theoretical position of the contact point with respect to the first Jacobian matrix J DH of the kinematic parameters can be expressed as follows:
Figure PCTCN2019088251-appb-000001
Figure PCTCN2019088251-appb-000001
其中,k为可辨识的DH参数个数,其具体取值与标定机器人的轴数相关。本实施例中采用六轴串联机器人时,由于第一轴的四个相关参数不可辨识,k可以等于20。x 11……z nm是利用记录的轴角度值通过名义DH参数正解后得到的接触点的理论位置的坐标;DH 1……DH k是名义DH参数。 Among them, k is the number of identifiable DH parameters, and its specific value is related to the number of axes of the calibration robot. When a six-axis tandem robot is used in this embodiment, since the four related parameters of the first axis are not identifiable, k can be equal to 20. x 11 ……z nm are the coordinates of the theoretical position of the contact point obtained by the positive solution of the nominal DH parameter using the recorded axis angle value; DH 1 ……DH k is the nominal DH parameter.
S2014:建立如下公式(1)所示的第一线性关系方程:S2014: Establish the first linear relationship equation shown in the following formula (1):
Δp=J DHΔDH   (1) Δp=J DH ΔDH (1)
具体地,根据机器人的运动学原理,可以推导出DH参数误差和接触点的位置误差存在如上述公式(1)所示的近似线性关系。其中,Δp表示接触点的位置的误差矩阵,J DH表示第一雅格比矩阵,ΔDH表示运动学参数的误差矩阵。 Specifically, according to the kinematics principle of the robot, it can be deduced that there is an approximately linear relationship between the DH parameter error and the position error of the contact point as shown in the above formula (1). Among them, Δp represents the error matrix of the position of the contact point, J DH represents the first Jacobian matrix, and ΔDH represents the error matrix of the kinematic parameters.
S202:建立标准工件的拟合半径误差与接触点的位置误差之间的第二线性关系方程。S202: Establish a second linear relationship equation between the fitting radius error of the standard workpiece and the position error of the contact point.
其中,由于标准工件的拟合半径是利用接触点的理论位置拟合得到的,因此标准工件的拟合半径误差是由于接触点的位置误差导致的,可以建立标准工件的拟合半径误差与接触点的位置误差之间的第二线性关系方程。Among them, since the fitting radius of the standard workpiece is fitted by the theoretical position of the contact point, the fitting radius error of the standard workpiece is caused by the position error of the contact point, and the fitting radius error and contact of the standard workpiece can be established The second linear relationship equation between the position errors of the points.
由于线性关系方程可以采用矩阵等式进行表达,求解矩阵等式即可以方便快捷地求解出线性关系方程的解,因此,如图6所示,步骤S202可以包括:Since the linear relation equation can be expressed by using a matrix equation, the solution of the linear relation equation can be solved conveniently and quickly by solving the matrix equation. Therefore, as shown in FIG. 6, step S202 may include:
S2021:将标准工件的拟合半径与实际半径之差作为元素,建立标准工件的拟合半径误差矩阵。S2021: Use the difference between the fitting radius of the standard workpiece and the actual radius as an element to establish a fitting radius error matrix of the standard workpiece.
具体地,当标准工件采用标准球工件时,利用多组接触点的理论位置进行球面拟合,即可以得到多个该标准工件的拟合半径r i,而该标准工件的实际半径r在选取标准工件时即可以预先得到,则将多组拟合半径r i和实际半径r之差Δr i=r i-r作为元素,可以建立标准工件的拟合半径误差矩阵Δr=(Δr 1 … Δr n) T,n为记录标定机器人各轴的角度时采用的标准工件的n个位姿。 Specifically, when the standard workpiece is a standard spherical workpiece, the theoretical positions of multiple sets of contact points are used for spherical fitting, that is, multiple fitting radii r i of the standard workpiece can be obtained, and the actual radius r of the standard workpiece is selected The standard workpiece can be obtained in advance, and the difference between multiple sets of fitting radius r i and the actual radius r Δr i =r i -r can be used as the element to establish the fitting radius error matrix of the standard workpiece Δr = (Δr 1 … Δr n ) T , n is the n poses of the standard workpiece used when recording the angle of each axis of the robot.
S2022:获取标准工件的拟合半径关于接触点的理论位置的第二雅格比矩阵。S2022: Obtain the second Jacobian matrix of the fitting radius of the standard workpiece with respect to the theoretical position of the contact point.
具体地,雅各比矩阵是由一阶导数构成的矩阵,则标准工件的拟合半径关于接触点的理论位置的第二雅格比矩阵J p可以表示如下: Specifically, the Jacobian matrix is a matrix composed of first-order derivatives, and the second Jacobian matrix J p of the fitting radius of the standard workpiece with respect to the theoretical position of the contact point can be expressed as follows:
Figure PCTCN2019088251-appb-000002
Figure PCTCN2019088251-appb-000002
其中,r 1……r n是拟合得到的拟合半径;x 11……z nm是利用记录的n*m组轴角度值通过名义DH参数正解后得到的接触点的理论位置的坐标。 Among them, r 1 ……r n is the fitting radius obtained by fitting; x 11 ……z nm is the coordinate of the theoretical position of the contact point obtained by using the recorded n*m set of axis angle values through the nominal DH parameter positive solution.
S2023:建立如下公式(2)所示的第二线性关系方程:S2023: Establish a second linear relationship equation shown in the following formula (2):
Δr=J pΔp    (2) Δr=J p Δp (2)
具体地,可以推导出拟合半径误差和接触点的位置误差存在如上述公式(2)所示的近似线性关系。其中,Δr表示标准工件的拟合半径误差矩阵,J p表示第二雅格比矩阵,Δp表示接触点的位置的误差矩阵。 Specifically, it can be deduced that there is an approximately linear relationship between the fitting radius error and the position error of the contact point as shown in the above formula (2). Among them, Δr represents the fitting radius error matrix of the standard workpiece, J p represents the second Jacobian matrix, and Δp represents the error matrix of the position of the contact point.
S203:结合第一线性关系方程和第二线性关系方程,建立该拟合半径误差与运动学参数误差之间的第三线性关系方程。S203: Combine the first linear relationship equation and the second linear relationship equation to establish a third linear relationship equation between the fitting radius error and the kinematic parameter error.
具体地,由于拟合半径误差可以计算得到,且拟合半径误差与接触点的位置误差之间存在第二线性关系方程,而接触点的位置误差与运动学参数误差之间存在第一线性关系方程,因此结合第一线性关系方程和第二线性关系方程,可以建立该拟合半径误差与运动学参数误差之间的第三线性关系方程。Specifically, since the fitting radius error can be calculated, and there is a second linear relationship equation between the fitting radius error and the position error of the contact point, and there is a first linear relationship between the position error of the contact point and the kinematic parameter error Equation, therefore combining the first linear relationship equation and the second linear relationship equation, the third linear relationship equation between the fitting radius error and the kinematic parameter error can be established.
可选地,当第一线性关系方程为上述公式(1),第二线性关系方程为上述公式(2)时,如图6所示,步骤S203包括:Optionally, when the first linear relationship equation is the above formula (1) and the second linear relationship equation is the above formula (2), as shown in FIG. 6, step S203 includes:
S2031:将第一线性关系方程代入第二线性关系方程,得到如下公式(3)所示的第三线性关系方程:S2031: Substituting the first linear relationship equation into the second linear relationship equation to obtain the third linear relationship equation shown in the following formula (3):
Δr=JΔDH   (3)Δr=JΔDH (3)
其中,J=J pJ DHAmong them, J=J p J DH .
其中,上述步骤S201~S203只需要执行一次,其执行过程只需要在步骤S133 之前即可,得到该第三线性关系方程后,只需要将对应数据代入即可以计算出所需的参数。The above steps S201 to S203 only need to be executed once, and the execution process only needs to be performed before step S133. After the third linear relationship equation is obtained, the required parameters can be calculated by substituting corresponding data.
继续参阅图5,步骤S133具体包括:Continue to refer to FIG. 5, step S133 specifically includes:
S204:将拟合半径误差代入该第三线性关系方程中,求解该第三线性关系方程,以得到标定机器人的实际运动学参数。S204: Substitute the fitting radius error into the third linear relationship equation, and solve the third linear relationship equation to obtain actual kinematic parameters of the calibration robot.
当得到该第三线性关系方程和拟合半径误差后,则可以将拟合半径误差代入该第三线性关系方程中,求解该第三线性关系方程,则可以计算得到标定机器人的运动学参数误差。然后,由于标定机器人的名义运动学参数可以事先得到,利用该名义运动学参数叠加该运动学参数误差,则可以得到标定机器人的实际运动学参数。After the third linear relationship equation and the fitting radius error are obtained, the fitting radius error can be substituted into the third linear relationship equation, and the third linear relationship equation can be solved, then the kinematic parameter error of the calibration robot can be calculated . Then, since the nominal kinematic parameters of the calibration robot can be obtained in advance, the actual kinematic parameters of the calibration robot can be obtained by superimposing the error of the kinematic parameter with the nominal kinematic parameters.
其中,当参数较多时,线性方程利用矩阵运算可以方便快速地求解,因此,如图6所示,步骤S204可以包括:Among them, when there are many parameters, the linear equation can be solved conveniently and quickly by matrix operation. Therefore, as shown in FIG. 6, step S204 may include:
S2041:求解第三线性关系方程,得到标定机器人的运动学参数的误差矩阵。S2041: Solve the third linear relation equation to obtain the error matrix of the kinematic parameters of the calibration robot.
其中,该标定机器人的运动学参数的误差矩阵为标定机器人的名义DH参数和实际DH参数的误差形成的矩阵。Among them, the error matrix of the kinematic parameters of the calibration robot is a matrix formed by the errors between the nominal DH parameters of the calibration robot and the actual DH parameters.
S2042:将标定机器人的名义运动学参数和运动学参数的误差矩阵叠加,得到标定机器人的实际运动学参数。S2042: Superimpose the nominal kinematic parameters of the calibration robot and the error matrix of the kinematic parameters to obtain the actual kinematic parameters of the calibration robot.
具体地,该第三线性关系方程可以采用如公式(3)所示的矩阵等式,此时,利用矩阵逆运算,则可以得到该第三线性关系方程的解,即可以得到标定机器人的运动学参数的误差矩阵,然后,根据该运动学参数的误差矩阵与标定机器人的名义运动学参数进行运算,则可以得到标定机器人的实际运动学参数。Specifically, the third linear relationship equation can adopt the matrix equation shown in formula (3). In this case, the matrix inverse operation can be used to obtain the solution of the third linear relationship equation, that is, the movement of the calibration robot can be obtained. Then, according to the error matrix of the kinematic parameters and the nominal kinematic parameters of the calibration robot, the actual kinematic parameters of the calibration robot can be obtained.
本实施例中,预先建立拟合半径误差与运动学参数误差之间的第三线性关系方程之后,只需要在得到拟合半径误差后,将该拟合半径误差代入该第三线性关系方程,利用矩阵逆运算,则可以简单快捷地计算得到该标定机器人的实际运动学参数。In this embodiment, after the third linear relationship equation between the fitting radius error and the kinematic parameter error is established in advance, it is only necessary to substitute the fitting radius error into the third linear relationship equation after the fitting radius error is obtained. Using the matrix inverse operation, the actual kinematic parameters of the calibration robot can be calculated simply and quickly.
如图7所示,本申请机器人运动学参数自标定系统第一实施例包括:标定 机器人A和参考机器人B。As shown in Figure 7, the first embodiment of the robot kinematic parameter self-calibration system of the present application includes: a calibration robot A and a reference robot B.
其中,标定机器人A的法兰安装有末端执行器10,参考机器人B的法兰安装有标准工件20。Among them, the flange of the calibration robot A is installed with an end effector 10, and the flange of the reference robot B is installed with a standard workpiece 20.
该参考机器人B用于改变标准工件20的位姿。The reference robot B is used to change the pose of the standard workpiece 20.
该标定机器人A用于执行指令以实现本申请机器人运动学参数自标定方法第一或第二实施例所提供的方法。The calibration robot A is used to execute instructions to implement the method provided in the first or second embodiment of the robot kinematic parameter self-calibration method of this application.
其中,标定的运动学参数个数与标定机器人A的类型相关。本实施例中,该标定机器人A可以选用六轴串联机器人。Among them, the number of calibrated kinematics parameters is related to the type of calibration robot A. In this embodiment, the calibration robot A can be a six-axis tandem robot.
为了使得标定机器人A可以接触到标准工件20表面201的不同位置,该标定机器人A和参考机器人B相对设置,从而使得标定机器人A和参考机器人B的灵巧工作空间有较大的重合,也就是使得二者机械臂的移动空间重合度较大,例如重合度达到至少60%。In order to enable the calibration robot A to touch different positions on the surface 201 of the standard workpiece 20, the calibration robot A and the reference robot B are arranged relative to each other, so that the smart working spaces of the calibration robot A and the reference robot B have a larger overlap, that is, The moving space of the two robot arms has a large overlap, for example, the overlap reaches at least 60%.
为了满足标定精度的要求,该标定机器人A的末端执行器10可以选用重复精度小于或等于1um的机床测头,该标准工件20可以选用有较高的球面度和表面光滑度的三坐标检具标准球。In order to meet the requirements of calibration accuracy, the end effector 10 of the calibration robot A can use a machine tool probe with a repeatability less than or equal to 1um, and the standard workpiece 20 can use a three-coordinate inspection tool with higher sphericity and surface smoothness. Standard ball.
本实施例的机器人运动学参数自标定系统中,利用法兰上安装有标准工件的参考机器人辅助标定,标定工具简单,效率高,且在标定时,只需一次输入标定机器人和参考机器人的运动指令,标定过程中标定机器人和参考机器人即可以自动运动和计算,无需人工干预,所以标定自动化程度高,适用于机器人生产过程中大批量的标定需求。In the robot kinematics parameter self-calibration system of this embodiment, the reference robot with standard workpieces mounted on the flange is used to assist the calibration. The calibration tool is simple and efficient. During the calibration, only the movement of the calibration robot and the reference robot needs to be input once. In the process of calibration, the calibration robot and the reference robot can automatically move and calculate without manual intervention, so the calibration has a high degree of automation, which is suitable for large-scale calibration requirements in the robot production process.
如图8所示,本申请机器人运动学参数自标定系统第二实施例的结构与本申请机器人运动学参数自标定系统第一实施例的结构类似,不同之处在于,进一步包括:控制装置C,连接标定机器人A和参考机器人B,用于控制标定机器人A和参考机器人B的运动。As shown in FIG. 8, the structure of the second embodiment of the robot kinematic parameter self-calibration system of the present application is similar to the structure of the first embodiment of the robot kinematic parameter self-calibration system of the present application, except that it further includes: a control device C , Connect the calibration robot A and the reference robot B to control the movement of the calibration robot A and the reference robot B.
其中,该控制装置C可以是计算机、后台服务器或总控制器等控制设备,其可以向标定机器人A和参考机器人B输出控制指令,控制标定机器人A和参 考机器人B的运动。Wherein, the control device C can be a computer, a background server or a master controller and other control equipment, which can output control instructions to the calibration robot A and the reference robot B, and control the movement of the calibration robot A and the reference robot B.
此外,该控制装置C还可以存储标定机器人A和参考机器人B的运动数据,如各轴的角度值等。该控制装置C还可以接收用户或控制人员的操控指令,以根据该操控指令控制标定机器人A和参考机器人B的运动。In addition, the control device C can also store the movement data of the calibration robot A and the reference robot B, such as the angle value of each axis. The control device C can also receive a manipulation instruction from a user or a controller, so as to control the movement of the calibration robot A and the reference robot B according to the manipulation instruction.
如图9所示,本申请存储装置一实施例中,存储装置90内部存储有程序文件901,该程序文件901被执行可实现如本申请机器人运动学参数自标定方法第一或第二实施例所提供的方法。As shown in FIG. 9, in an embodiment of the storage device of the present application, a program file 901 is stored inside the storage device 90, and the program file 901 can be executed to realize the first or second embodiment of the robot kinematic parameter self-calibration method of the present application The method provided.
其中,该存储装置90可以是便携式存储介质如U盘、光盘,也可以是其他存储设备如硬盘等,还可以是服务器、移动终端、机器人或可集成于上述设备中的独立部件,例如主控芯片等。Wherein, the storage device 90 can be a portable storage medium such as a U disk, an optical disk, or other storage devices such as a hard disk, etc., and can also be a server, a mobile terminal, a robot, or an independent component that can be integrated into the above device, such as a master Chip etc.
本实施例中,存储装置中存储的程序被执行时,利用法兰上安装有标准工件的参考机器人辅助标定,标定工具简单,效率高,且在标定时,只需一次输入标定机器人和参考机器人的运动指令,标定过程中标定机器人和参考机器人即可以自动运动和计算,无需人工干预,所以标定自动化程度高,适用于机器人生产过程中大批量的标定需求。In this embodiment, when the program stored in the storage device is executed, a reference robot with a standard workpiece mounted on the flange is used to assist the calibration. The calibration tool is simple and efficient. During calibration, only one input of the calibration robot and the reference robot is required. In the calibration process, the calibration robot and the reference robot can automatically move and calculate without manual intervention, so the calibration has a high degree of automation, which is suitable for large-scale calibration requirements in the robot production process.
以上所述仅为本申请的实施方式,并非因此限制本申请的专利范围,凡是利用本申请说明书及附图内容所作的等效结构或等效流程变换,或直接或间接运用在其他相关的技术领域,均同理包括在本申请的专利保护范围内。The above are only implementations of this application, and do not limit the scope of this application. Any equivalent structure or equivalent process transformation made by using the description and drawings of this application, or directly or indirectly applied to other related technologies In the same way, all fields are included in the scope of patent protection of this application.

Claims (20)

  1. 一种机器人运动学参数自标定方法,其特征在于,包括:A method for self-calibration of robot kinematics parameters, characterized in that it comprises:
    标定机器人将末端执行器多次接触标准工件表面,并记录每次接触时所述标定机器人各轴的角度,所述标准工件安装于参考机器人的法兰;The calibration robot touches the end effector to the surface of the standard workpiece multiple times, and records the angle of each axis of the calibration robot at each contact, and the standard workpiece is installed on the flange of the reference robot;
    所述参考机器人改变所述标准工件的位姿,所述标定机器人重复执行以所述末端执行器多次接触标准工件表面,并记录每次接触时所述标定机器人各轴的角度的步骤,以获取所述标定机器人的多组轴角度值;The reference robot changes the pose of the standard workpiece, and the calibration robot repeatedly executes the steps of contacting the surface of the standard workpiece with the end effector multiple times and recording the angles of each axis of the calibration robot during each contact to Acquiring multiple sets of axis angle values of the calibration robot;
    利用所述多组轴角度值、所述标定机器人的名义运动学参数以及所述标准工件的实际半径,得到所述标定机器人的实际运动学参数。Using the multiple sets of axis angle values, the nominal kinematic parameters of the calibration robot, and the actual radius of the standard workpiece, the actual kinematic parameters of the calibration robot are obtained.
  2. 根据权利要求1所述的方法,其特征在于,所述标定机器人的末端执行器多次接触标准工件表面,并记录每次接触时所述标定机器人各轴的角度包括:The method according to claim 1, wherein the end effector of the calibration robot contacts the surface of the standard workpiece multiple times, and recording the angle of each axis of the calibration robot during each contact comprises:
    所述标定机器人的末端执行器以不同姿态接触所述标准工件表面的不同位置m次,并记录每次接触时所述标定机器人各轴的角度。The end effector of the calibration robot contacts different positions on the surface of the standard workpiece m times in different postures, and records the angle of each axis of the calibration robot at each contact.
  3. 根据权利要求2所述的方法,其特征在于,所述参考机器人改变所述标准工件的位姿,所述标定机器人重复执行以所述末端执行器多次接触标准工件表面,并记录每次接触时所述标定机器人各轴的角度的步骤,以获取所述标定机器人的多组轴角度值包括:The method according to claim 2, wherein the reference robot changes the pose of the standard workpiece, and the calibration robot repeatedly executes the end effector contacting the surface of the standard workpiece multiple times, and records each contact The step of calibrating the angles of each axis of the robot to obtain multiple sets of axis angle values of the calibration robot includes:
    所述参考机器人改变所述标准工件的位姿n-1次;The reference robot changes the pose of the standard workpiece n-1 times;
    每改变一次所述标准工件的位姿,所述标定机器人将末端执行器以不同姿态接触所述标准工件表面的不同位置,并记录每次接触时所述标定机器人各轴的角度,以得到m*n组所述标定机器人各轴的角度。Every time the posture of the standard workpiece is changed, the calibration robot will contact the end effector at different positions on the surface of the standard workpiece in different postures, and record the angle of each axis of the calibration robot during each contact to obtain m *The angle of each axis of the calibration robot described in group n.
  4. 根据权利要求1所述的方法,其特征在于,所述利用所述多组轴角度值、所述标定机器人的名义运动学参数以及所述标准工件的实际半径,得到所述标定机器人的实际运动学参数包括:The method according to claim 1, wherein the actual movement of the calibration robot is obtained by using the multiple sets of axis angle values, the nominal kinematic parameters of the calibration robot, and the actual radius of the standard workpiece Learning parameters include:
    利用所述多组轴角度值和所述标定机器人的名义运动学参数,计算得到每 组所述轴角度值对应的所述末端执行器与所述标准工件表面的接触点理论位置,其中在所述标准工件的同一位姿下记录得到的所述标定机器人各轴的角度形成一组所述轴角度值;Using the multiple sets of axis angle values and the nominal kinematics parameters of the calibration robot, the theoretical position of the contact point between the end effector and the surface of the standard workpiece corresponding to each set of the axis angle values is calculated, wherein The angles of each axis of the calibration robot recorded under the same pose of the standard workpiece form a set of axis angle values;
    利用多组所述接触点理论位置,拟合得到每组所述接触点理论位置对应的所述标准工件的拟合半径,其中以一组所述轴角度值计算得到的多个所述接触点理论位置为一组所述接触点理论位置;Using multiple sets of the theoretical positions of the contact points, the fitting radius of the standard workpiece corresponding to each set of the theoretical positions of the contact points is obtained by fitting, wherein a plurality of the contact points are calculated by a set of the axis angle values The theoretical position is a set of theoretical positions of the contact points;
    根据所述拟合半径以及实际半径之间的拟合半径误差计算所述实际运动学参数。The actual kinematics parameters are calculated according to the fitted radius and the fitted radius error between the actual radius.
  5. 根据权利要求4所述的方法,其特征在于,The method according to claim 4, wherein:
    所述根据所述拟合半径以及实际半径之间的拟合半径误差计算所述实际运动学参数之前,包括:Before calculating the actual kinematic parameters according to the fitted radius and the fitted radius error between the actual radius, the method includes:
    建立所述接触点的位置误差与运动学参数误差之间的第一线性关系方程,其中所述运动学参数误差为所述实际运动学参数与所述名义运动学参数之间的误差;Establishing a first linear relationship equation between the position error of the contact point and the kinematic parameter error, wherein the kinematic parameter error is the error between the actual kinematic parameter and the nominal kinematic parameter;
    建立所述拟合半径误差与所述接触点的位置误差之间的第二线性关系方程;Establishing a second linear relationship equation between the fitting radius error and the position error of the contact point;
    结合所述第一线性关系方程和所述第二线性关系方程,建立所述拟合半径误差与所述运动学参数误差之间的第三线性关系方程;Combining the first linear relationship equation and the second linear relationship equation to establish a third linear relationship equation between the fitting radius error and the kinematic parameter error;
    所述根据所述拟合半径以及实际半径之间的拟合半径误差计算所述实际运动学参数包括:The calculating the actual kinematics parameters according to the fitted radius and the fitted radius error between the actual radius includes:
    将所述拟合半径误差代入所述第三线性关系方程中,求解所述第三线性关系方程,以得到所述标定机器人的实际运动学参数。The fitting radius error is substituted into the third linear relationship equation, and the third linear relationship equation is solved to obtain the actual kinematic parameters of the calibration robot.
  6. 根据权利要求5所述的方法,其特征在于,所述建立所述接触点的位置误差与运动学参数误差之间的第一线性关系方程包括:The method according to claim 5, wherein the establishing the first linear relationship equation between the position error of the contact point and the kinematic parameter error comprises:
    将所述接触点的理论位置和实际位置的差作为元素,建立所述接触点的位置的误差矩阵;Using the difference between the theoretical position and the actual position of the contact point as an element to establish an error matrix of the position of the contact point;
    将所述名义运动学参数和所述实际运动学参数的差作为元素,建立所述运 动学参数的误差矩阵;Using the difference between the nominal kinematics parameter and the actual kinematics parameter as an element to establish an error matrix of the kinematics parameter;
    获取所述接触点的理论位置关于所述运动学参数的第一雅格比矩阵;Acquiring the first Jacobian matrix of the theoretical position of the contact point with respect to the kinematic parameter;
    建立如下公式所示的所述第一线性关系方程:Establish the first linear relationship equation shown in the following formula:
    Δp=J DHΔDH; Δp=J DH ΔDH;
    其中,Δp表示所述接触点的位置的误差矩阵,J DH表示所述第一雅格比矩阵,ΔDH表示所述运动学参数的误差矩阵。 Wherein, Δp represents the error matrix of the position of the contact point, J DH represents the first Jacobian matrix, and ΔDH represents the error matrix of the kinematic parameter.
  7. 根据权利要求6所述的方法,其特征在于,所述建立所述标准工件的拟合半径误差与所述接触点的位置误差之间的第二线性关系方程包括:The method according to claim 6, wherein the establishing a second linear relationship equation between the fitting radius error of the standard workpiece and the position error of the contact point comprises:
    将所述标准工件的拟合半径与所述实际半径之差作为元素,建立所述标准工件的拟合半径误差矩阵;Using the difference between the fitting radius of the standard workpiece and the actual radius as an element to establish a fitting radius error matrix of the standard workpiece;
    获取所述标准工件的拟合半径关于所述接触点的理论位置的第二雅格比矩阵;Acquiring a second Jacobian matrix of the fitting radius of the standard workpiece with respect to the theoretical position of the contact point;
    建立如下公式所示的所述第二线性关系方程:Establish the second linear relationship equation shown in the following formula:
    Δr=J pΔp; Δr=J p Δp;
    其中,Δr表示所述标准工件的拟合半径误差矩阵,J p表示所述第二雅格比矩阵,Δp表示所述接触点的位置的误差矩阵。 Where, Δr represents the fitting radius error matrix of the standard workpiece, J p represents the second Jacobian matrix, and Δp represents the error matrix of the position of the contact point.
  8. 根据权利要求7所述的方法,其特征在于,所述结合所述第一线性关系方程和所述第二线性关系方程,建立所述标准工件的拟合半径误差与所述运动学参数误差之间的第三线性关系方程包括:The method according to claim 7, wherein the combination of the first linear relationship equation and the second linear relationship equation establishes the difference between the fitting radius error of the standard workpiece and the kinematic parameter error The third linear relationship equation between the two includes:
    将所述第一线性关系方程代入所述第二线性关系方程,得到如下公式所示的所述第三线性关系方程:Substituting the first linear relationship equation into the second linear relationship equation to obtain the third linear relationship equation shown in the following formula:
    Δr=JΔDH;Δr=JΔDH;
    其中,J=J pJ DHAmong them, J=J p J DH .
  9. 根据权利要求5所述的方法,其特征在于,所述求解所述第三线性关系方程,以得到所述标定机器人的实际运动学参数包括:The method according to claim 5, wherein the solving the third linear relationship equation to obtain the actual kinematic parameters of the calibration robot comprises:
    求解所述第三线性关系方程,得到所述标定机器人的运动学参数的误差矩 阵;Solving the third linear relation equation to obtain the error matrix of the kinematic parameters of the calibration robot;
    将所述标定机器人的名义运动学参数和所述运动学参数的误差矩阵叠加,得到所述标定机器人的实际运动学参数。The nominal kinematics parameters of the calibration robot and the error matrix of the kinematics parameters are superimposed to obtain the actual kinematics parameters of the calibration robot.
  10. 根据权利要求1-9任一项所述的方法,其特征在于,所述标定机器人和所述参考机器人相对设置。The method according to any one of claims 1-9, wherein the calibration robot and the reference robot are arranged relative to each other.
  11. 根据权利要求2所述的方法,其特征在于,所述标定机器人为六轴串联机器人,所述m的取值大于4。The method according to claim 2, wherein the calibration robot is a six-axis tandem robot, and the value of m is greater than 4.
  12. 根据权利要求3所述的方法,其特征在于,所述标定机器人为六轴串联机器人,所述n的取值大于20。The method according to claim 3, wherein the calibration robot is a six-axis tandem robot, and the value of n is greater than 20.
  13. 根据权利要求1所述的方法,其特征在于,所述标准工件为三坐标检具标准球。The method according to claim 1, wherein the standard workpiece is a three-coordinate gauge standard ball.
  14. 一种机器人运动学参数自标定系统,其特征在于,包括:标定机器人和参考机器人;A self-calibration system for robot kinematics parameters, which is characterized by comprising: a calibration robot and a reference robot;
    所述标定机器人的法兰安装有末端执行器,所述参考机器人的法兰安装有标准工件;An end effector is installed on the flange of the calibration robot, and a standard workpiece is installed on the flange of the reference robot;
    所述参考机器人用于改变所述标准工件的位姿;The reference robot is used to change the pose of the standard workpiece;
    所述标定机器人用于执行指令以实现如权利要求1-13任一项所述的机器人运动学参数自标定方法。The calibration robot is used to execute instructions to realize the robot kinematic parameter self-calibration method according to any one of claims 1-13.
  15. 根据权利要求14所述的系统,其特征在于,所述标定机器人和所述参考机器人相对设置。The system according to claim 14, wherein the calibration robot and the reference robot are arranged oppositely.
  16. 根据权利要求14所述的系统,其特征在于,所述标定机器人的末端执行器为重复精度小于或等于1um的机床测头。The system according to claim 14, wherein the end effector of the calibration robot is a machine tool probe with a repeatability less than or equal to 1um.
  17. 根据权利要求14所述的系统,其特征在于,所述标准工件为三坐标检具标准球。The system according to claim 14, wherein the standard workpiece is a three-coordinate gauge standard ball.
  18. 根据权利要求14所述的系统,其特征在于,进一步包括:控制装置,连接所述标定机器人和所述参考机器人,用于控制所述标定机器人和所述参考 机器人的运动。The system according to claim 14, further comprising: a control device connected to the calibration robot and the reference robot for controlling the movement of the calibration robot and the reference robot.
  19. 根据权利要求14所述的系统,其特征在于,所述标定机器人为六轴串联机器人。The system according to claim 14, wherein the calibration robot is a six-axis tandem robot.
  20. 一种存储装置,内部存储有程序文件,其特征在于,所述程序文件被执行以实现如权利要求1-13任一项所述的机器人运动学参数自标定方法。A storage device in which a program file is stored, wherein the program file is executed to realize the robot kinematic parameter self-calibration method according to any one of claims 1-13.
PCT/CN2019/088251 2019-05-24 2019-05-24 Method and system for self-calibrating robot kinematic parameter, and storage device WO2020237407A1 (en)

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