CN113510708A - Contact industrial robot automatic calibration system based on binocular vision - Google Patents
Contact industrial robot automatic calibration system based on binocular vision Download PDFInfo
- Publication number
- CN113510708A CN113510708A CN202110855774.2A CN202110855774A CN113510708A CN 113510708 A CN113510708 A CN 113510708A CN 202110855774 A CN202110855774 A CN 202110855774A CN 113510708 A CN113510708 A CN 113510708A
- Authority
- CN
- China
- Prior art keywords
- calibration
- robot
- coordinate system
- joint
- calibrated
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J9/00—Programme-controlled manipulators
- B25J9/16—Programme controls
- B25J9/1694—Programme controls characterised by use of sensors other than normal servo-feedback from position, speed or acceleration sensors, perception control, multi-sensor controlled systems, sensor fusion
- B25J9/1697—Vision controlled systems
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J9/00—Programme-controlled manipulators
- B25J9/16—Programme controls
- B25J9/1602—Programme controls characterised by the control system, structure, architecture
- B25J9/1605—Simulation of manipulator lay-out, design, modelling of manipulator
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J9/00—Programme-controlled manipulators
- B25J9/16—Programme controls
- B25J9/1656—Programme controls characterised by programming, planning systems for manipulators
- B25J9/1664—Programme controls characterised by programming, planning systems for manipulators characterised by motion, path, trajectory planning
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J9/00—Programme-controlled manipulators
- B25J9/16—Programme controls
- B25J9/1694—Programme controls characterised by use of sensors other than normal servo-feedback from position, speed or acceleration sensors, perception control, multi-sensor controlled systems, sensor fusion
Abstract
The invention discloses a contact type industrial robot automatic calibration system based on binocular vision, which relates to the field of industrial robot calibration, and utilizes a binocular camera to perform vision guidance, calculates the relative pose of a measuring device and a preset calibration pattern on a calibration frame through the binocular vision, further calculates the conversion relation between a measuring coordinate system and a calibration plate coordinate system, gradually approaches the tail end of a robot to be calibrated to each calibration ball in a sectional type mode, minimizes the influence of errors on the vision guidance, finally reaches a specified position, obtains the coordinates of the calibration ball under a robot base coordinate system, repeatedly forms error equation solution, completes calibration through compensation, does not need operators to perform manual alignment in the calibration process, reduces the technical requirements on the operators, can quickly complete the parameter calibration of the industrial robot under a general environment without human intervention, the calibration speed is fast, the accuracy is high, and the use is convenient.
Description
Technical Field
The invention relates to the field of industrial robot calibration, in particular to a binocular vision-based contact type automatic calibration system for an industrial robot.
Background
In industrial application, if an industrial robot needs to perform various operations, the accuracy of the industrial robot needs to be ensured to meet the requirement, but under the influence of many factors such as manufacturing, assembly, motion control and working environment, the actual motion accuracy of the industrial robot is different from an ideal motion model. It is therefore necessary to increase the accuracy of the movement of the industrial robot as much as possible by a feasible means so that the industrial robot can accurately reach the specified end position.
The industrial robot calibration technology is a main method for improving the motion precision of an industrial robot at present, and high-precision external measuring equipment is mainly adopted to accurately measure the coordinates of an end effector of the industrial robot during calibration. Modeling is carried out to industrial robot through reasonable model, discerns each item parameter in the industrial robot model again, through calculating the parameter error that the accuracy obtained each parameter to obtain industrial robot's actual parameter value, then combine the control system of industrial robot body and other control algorithm etc. to compensate each item parameter error of industrial robot, realize the improvement to industrial robot motion precision.
The calibration of the industrial robot mainly comprises the following four steps: the method comprises the following steps of kinematics modeling, data measurement, parameter identification and error compensation, wherein the data measurement is the most time-consuming, tedious and important link, and the accuracy of the data measurement directly influences the accuracy of a subsequent calibration result, so that how to quickly, accurately and conveniently measure and obtain data is the key of the calibration technology of the industrial robot.
The calibration method of the industrial robot can be mainly divided into open-loop calibration and closed-loop calibration. Open-loop calibration needs to complete measurement of pose data of the tail end of the mechanical arm by means of an external precision measuring instrument, common measuring instruments comprise a ball rod instrument, a three-coordinate measuring machine, a stay wire type displacement sensor, a theodolite, a laser tracker, binocular vision and the like, the measuring instruments are high in measuring accuracy, high in specificity and complexity, complex in use process and high in price, need to be used by specially trained personnel, have certain requirements on measuring environments, and improper measuring methods and measuring environments can cause great errors in measuring results.
The basic principle of the closed-loop calibration method is that the tail end of the mechanical arm is limited by using externally applied space physical constraints so that the mechanical arm can operate in a specified range, such as a point, a straight line, a plane and the like, then joint angle data are obtained through a control system of the mechanical arm, and pose data of the tail end of the mechanical arm are obtained through positive kinematics. The method has the advantages of simple measurement process, low cost and low requirements on measurement environment and operation process, but the method generally needs to manually operate the industrial robot to enable the end effector to reach the limit point and to be repeatedly carried out, the dependence on manual operation is high, the manual operation speed is low, the pose relationship between the end effector and the limit point needs to be repeatedly observed to send a proper operation instruction, errors are easily caused in manual operation, equipment damage is even caused, and the like, and the precision is low.
In summary, in the existing calibration method for the industrial robot, no matter open-loop calibration or closed-loop calibration is performed, the accuracy and convenience of the data measurement process are difficult to guarantee at the same time, so that the efficiency of the whole calibration process is low.
Disclosure of Invention
The invention provides a contact type industrial robot automatic calibration system based on binocular vision aiming at the problems and the technical requirements, and the technical scheme of the invention is as follows:
a contact type industrial robot automatic calibration system based on binocular vision comprises a robot to be calibrated, and the system comprises an upper computer, a measuring device, a calibration frame and a binocular camera;
the measuring device is fixed at the tail end of the robot to be calibrated and comprises a plurality of angle sensors, a measuring rod of each angle sensor is fixed with a finger-shaped joint, the other end of each finger-shaped joint is provided with a joint contact, each finger-shaped joint forms a mechanical paw structure, and a measuring coordinate system is established by taking the vertex of one angle sensor as an origin; the binocular camera is fixed at the tail end of the robot to be calibrated, and at least one joint contact always exists in the visual field of the binocular camera;
the calibration frame is arranged in the operation range of the robot to be calibrated, the calibration frame comprises a calibration plane plate and a vertical frame on the calibration plane plate, a plurality of calibration balls are fixed on the vertical frame, a preset calibration pattern is arranged on the calibration plane plate, and a calibration plate coordinate system is established by taking one vertex of the calibration plane plate as an origin;
the upper computer is connected with the robot to be calibrated, each sensor in the measuring device and the binocular camera, and the calibration method of the robot to be calibrated by the upper computer comprises the following steps:
establishing a robot kinematics model, determining a third coordinate conversion relation between a measurement coordinate system and a calibration plate coordinate system by using joint contacts in a binocular camera visual field and a preset calibration pattern of a calibration frame under a standard configuration of a robot to be calibrated, controlling the movement of the robot to be calibrated to enable the joint contacts to approach the calibration balls by adopting sectional trajectory planning according to the coordinate of the calibration balls under the calibration plate coordinate system and the third coordinate conversion relation through inverse kinematics, and obtaining angle values of all angle sensors and angle values of all joints of the robot to be calibrated as a group of acquisition data corresponding to the calibration balls until all the joint contacts contact the calibration balls;
and obtaining the nominal pose of each calibration ball under the base coordinate system according to a group of acquired data corresponding to each different calibration ball, and compensating the robot kinematic model by combining the relative distance between each calibration ball to finish calibration.
The further technical scheme is that the method adopts sectional track planning to control the motion of the robot to be calibrated so that the joint contact point approaches to the calibration ball, and comprises the following steps:
when the robot to be calibrated is in a standard pose, each joint contact point and a preset calibration pattern on a calibration frame appear in the visual field of a binocular camera, the coordinates of the top points of the joint contact points and a calibration plane plate under a camera coordinate system are determined according to image information collected by the binocular camera, and the coordinates of the joint contact points under a measurement coordinate system and the coordinates of a calibration ball under the calibration coordinate system are combined to determine the coordinates of the calibration ball under the measurement coordinate system in the standard pose;
controlling the tail end position of the robot to be calibrated to move towards the direction close to the calibration ball by a preset amplitude to the current pose through inverse kinematics according to the coordinates of the calibration ball under the measurement coordinate system, determining joint contacts and the calibration ball in the camera coordinate system according to image information acquired by a binocular camera under the current pose, and determining the coordinates of the joint contacts and the calibration ball under the measurement coordinate system under the current pose by combining the coordinates of the joint contacts under the measurement coordinate system and the coordinates of the calibration ball under the calibration coordinate system;
and re-executing the step of controlling the tail end position of the robot to be calibrated to move to the direction close to the calibration ball by the preset amplitude to the current pose through inverse kinematics according to the coordinates of the calibration ball in the measurement coordinate system until all the joint contacts are determined to be in contact with the calibration ball when all the angle sensors of the measuring device have angle changes.
According to the further technical scheme, in the process of collecting a group of collected data corresponding to one calibration ball, if the image information collected by the binocular camera detects that the joint contact in the visual field is shielded by the calibration ball and/or the data of the angle sensor is detected to be abnormally changed, the robot to be calibrated is controlled to return to the previous pose.
The measuring device comprises a measuring device, wherein each finger-shaped joint in the measuring device comprises a plurality of joint sections connected through middle joints, each middle joint is provided with a spring for connecting two adjacent joint sections, and the relative position of each joint section is kept unchanged in a natural state; when the finger-shaped joint is subjected to the external force action of the calibration ball and exceeds the elastic force action of the spring, the joint section overcomes the elastic force action of the spring and rotates around the middle joint relatively.
The calibration frame is characterized in that a preset calibration pattern with a preset area is arranged at each vertex of the calibration plane plate.
The further technical scheme is that at least four calibration balls are arranged on two sides of the vertical frame and on one side of the vertical frame facing the robot to be calibrated.
The further technical proposal is that the system comprises at least two calibration frames.
The further technical scheme is that the robot kinematics model is compensated by combining the relative distance between each calibration ball to complete calibration, and the calibration method comprises the following steps:
and constructing a distance square error model by combining the nominal poses of all the calibration balls under the base coordinate system and the relative distances among all the calibration balls, identifying the conversion relation error between the measurement coordinate system and the tail end coordinate system by using a parameter identification algorithm, and compensating the conversion relation error into the robot kinematics model.
The beneficial technical effects of the invention are as follows:
the application discloses contact industrial robot automatic calibration system based on binocular vision, only need carry out the demarcation of binocular camera, need not carry out the hand eye and mark, calculate the relative position appearance of preset calibration pattern on measuring device and the calibration frame through binocular vision, and then calculate the transform relation of measuring coordinate system and calibration board coordinate system, there is certain error, nevertheless make with the mode of sectional type and wait to mark the terminal each calibration ball that is close gradually of robot, make the error reach minimum to the influence of vision guide, finally reach the assigned position, do not need operating personnel to carry out manual alignment, the technical requirement to operating personnel has been reduced. The calibration system has the advantages that the coordinates of the calibration ball nominally under the robot base coordinate system are obtained, the error equation is repeatedly formed for many times, the kinematic parameter error of the robot is obtained through calculation, the calibration is completed after compensation, the calibration speed is increased in the calibration process realized by the system, the parameter calibration of the industrial robot under the general environment can be quickly completed under the condition of no human intervention, and the calibration speed is high, the accuracy is high, and the use is convenient.
The spring is added at the finger-shaped joint, so that the fault tolerance rate of the calibration ball in the automatic calibration process is improved, and the safety of the calibration process is improved by the spring device.
Drawings
Fig. 1 is a schematic system structure diagram of an automatic calibration system of a contact industrial robot disclosed in the present application.
Fig. 2 is a schematic view of the installation of the measuring device and the binocular camera at the end of the robot to be calibrated.
Fig. 3 is a schematic view of another view of the measuring device and the binocular camera of the robot end to be calibrated.
Fig. 4 is a schematic diagram of a calibration process of the contact industrial robot automatic calibration system disclosed in the present application.
Detailed Description
The following further describes the embodiments of the present invention with reference to the drawings.
The application discloses contact industrial robot automatic calibration system based on binocular vision, please refer to fig. 1, this system includes treats calibration robot 1, host computer 2, measuring device 3, calibration frame 4 and binocular camera 5.
The calibration frame 4 is disposed in the operation range of the robot 1 to be calibrated, the calibration frame 4 includes a calibration plane plate 41 and a stand 42 thereon, a preset calibration pattern 44 is disposed on the calibration plane plate 41, in one embodiment, the calibration frame 4 has a preset calibration pattern 44 with a predetermined area at each vertex of the calibration plane plate 41, and the predetermined calibration pattern 44 is, for example, a checkerboard pattern. The height of the stand 42 is determined by the size of the robot 1 to be calibrated, and is approximately half of the height of the standard pose of the robot 1 to be calibrated. The stand 42 is fixed with a plurality of calibration balls 43, the calibration balls 43 have predetermined marks for identification, for example, the calibration balls 43 are white and have black cross-shaped predetermined marks thereon, and the roundness and radius errors of the calibration balls 43 should be in the micrometer range to ensure the measurement accuracy. Optionally, the calibration frame 4 is provided with at least four calibration balls 43 on both sides of the stand 42 and on a side of the stand facing the robot 1 to be calibrated. The method has the advantages that the action amplitude is as large as possible in the calibration process, and the optimal calibration configuration is achieved, so that the final calibration precision is improved. A calibration plate coordinate system is established with a vertex of the calibration plane plate 41 as an origin, as shown in fig. 1, a vertex of the calibration plane plate 41 as an origin Oc, a plane where the calibration plane plate 41 is located as an xy plane, and an upward direction perpendicular to the calibration plane plate 41 as a z-axis direction, to establish and obtain a calibration plate coordinate system OcXcYcZc, coordinates of each calibration ball in the calibration plate coordinate system can be calibrated by using a three-coordinate measuring machine, the coordinates of each calibration ball, that is, spherical coordinates of the calibration ball, are higher in calibration precision, and the precision of the finally obtained measurement data is higher. In practical application, the system comprises one calibration frame or at least two calibration frames with the structure in different positions in the operation range of the robot 1 to be calibrated.
The measuring device 3 is fixed at the end of the robot 1 to be calibrated, a flange plate is arranged on the measuring device 3 and connected with the end of the robot 1 to be calibrated, as shown in fig. 2 and 3, the measuring device 3 comprises a plurality of angle sensors 31, a finger joint 32 is fixed on a measuring rod of each angle sensor 31, the other end of each finger joint 32 is provided with a joint contact 33, the joint contact 33 is generally a round ball with a known radius, each finger joint 32 forms a mechanical gripper structure, the number of the specific finger joints 32 is configured as required, and the application illustrates that the measuring device comprises three finger joints 32 as an example. When the mechanical paw structure of the measuring device 3 contacts the calibration ball, the tail ends of the three finger joints 32 slide to the periphery of the calibration ball, so that the angle sensor is driven to rotate. A measurement coordinate system O7X7Y7Z7 is established with the vertex of one of the angle sensors as an origin O7, the plane parallel to the end of the robot 1 to be calibrated as the xy plane, and the plane perpendicular to the xy plane and in front of the robot 1 to be calibrated as the Z axis, and due to the problem of illustration, O7 is not shown in the vertices of one of the angle sensors in fig. 1 and 2. Based on the already established measurement coordinate system O7X7Y7Z7, the coordinates of the respective joint contact points initially in the measurement coordinate system O7X7Y7Z7 can be calibrated by means of a three-coordinate measuring machine.
Each finger joint 32 in the measuring device 3 comprises a plurality of joint segments connected by an intermediate joint 34, for example, fig. 2 includes two joint segments, a spring 35 is disposed at each intermediate joint 34 to connect two adjacent joint segments, and under the elastic force of the spring 35, the relative position of each joint segment is kept unchanged in a natural state and cannot rotate around the intermediate joint 34. When the finger joint 32 is subjected to the external force action of the calibration ball and exceeds the elastic force action of the spring 35, the joint sections overcome the elastic force action of the spring to enable the spring 35 to generate elastic deformation, and the two joint sections rotate relatively around the middle joint, so that the measuring device 3 cannot be damaged when rigid collision occurs, and the safety during collision is greatly improved.
The measuring device 3 of this application adopts angle sensor to combine the structure of finger joint, rather than using displacement sensor, this is because displacement sensor's installation is very fixed, can only carry out concertina movement, is being close the in-process of demarcation ball, and is relatively poor to the fault-tolerant rate of collision demarcation ball, causes the damage of equipment very easily to after displacement sensor reaches the range limit, just can't advance again. In the structure, the angle sensor can enable the finger joints to move back and forth, and the spring device between the finger joints can ensure that the tail end device cannot be damaged when rigid collision occurs, so that the safety during collision is greatly improved.
The binocular camera 5 is fixed at the end of the robot 1 to be calibrated, and at least one joint contact point 33 always exists in the field of view of the binocular camera. In one example of the present application, the binocular camera 5 is fixed on one side, for example, above the measuring device 3 by the camera bracket 51, and the binocular camera 5 is installed above the measuring device 3 instead of being installed outside the robot 1 to be calibrated, so as to prevent the calibration ball from being blocked when the robot 1 to be calibrated moves, so that the vision guide is in the condition that the target object is in the visual field. Meanwhile, when the target object is out of the visual field, the robot 1 to be calibrated can conveniently adjust the end position so that the target object appears in the visual field of the binocular camera. And establishing a camera coordinate system O8X8Y8Z8 by taking the binocular camera as an origin O8, taking a plane parallel to the tail end of the robot 1 to be calibrated as an xy plane, and taking a plane perpendicular to the xy plane and in front of the robot 1 to be calibrated as a Z axis.
The upper computer 2 is connected with the robot 1 to be calibrated, each sensor in the measuring device 3 and the binocular camera 5, please refer to fig. 4, and the calibration method of the robot to be calibrated by the upper computer 2 comprises the following steps:
the robot kinematics model is established, a conversion relation between a base coordinate system O0X0Y0Z0 and a terminal coordinate system O6X6Y6Z6 of the robot 1 to be calibrated and a conversion relation between the terminal coordinate system O6X6Y6Z6 and a measurement coordinate system O7X7Y7Z7 are obtained, the base coordinate system and the terminal coordinate system are common coordinate systems in the robot calibration field, and the description is omitted in the application.
Under the standard configuration of the robot to be calibrated, determining a third coordinate conversion relation between a measurement coordinate system and a calibration plate coordinate system by using joint contacts in a binocular camera visual field and a preset calibration pattern of a calibration frame, controlling the movement of the robot to be calibrated to enable the joint contacts to approach the calibration balls by adopting sectional type trajectory planning according to the coordinate of the calibration balls under the calibration plate coordinate system and the third coordinate conversion relation based on inverse kinematics, and acquiring the angle value of each angle sensor and the angle value of each joint of the robot to be calibrated as a group of acquisition data corresponding to the calibration balls until each joint contact contacts contact the calibration balls.
Specifically, under the standard pose of the robot 1 to be calibrated, the calibration frame is placed in the operation range of the robot 1 to be calibrated, and it is ensured that each joint contact 33 and the preset calibration pattern on the calibration frame appear in the field of view of the binocular camera 5, in the example of fig. 1, it is also required to ensure that each joint contact 33 and the complete checkerboard pattern at least one vertex of the calibration plane plate 41 appear in the field of view of the binocular camera 5. And determining the coordinates of the joint contact points and the top points of the calibration plane plate under the camera coordinate system according to the image information acquired by the binocular camera. Because the coordinates of the joint contact points in the measurement coordinate system are known, the coordinate conversion relation of the measurement coordinate system relative to the camera coordinate system can be obtained according to the coordinates of the joint contact points in the measurement coordinate system and the coordinates of the joint contact points in the camera coordinate system, and the coordinates of the calibration ball in the measurement coordinate system in the standard pose are calculated by combining the known coordinates of the calibration ball in the calibration coordinate system. According to the coordinates of the calibration ball in the measurement coordinate system, the joint contact point 33 at the tail end of the robot 1 to be calibrated can be controlled to approach the calibration ball through inverse kinematics and trajectory planning.
The robot parameters are not calibrated at the moment, so that the trajectory planning is not accurate enough, the method adopts a sectional trajectory planning method, and the tail end position of the robot to be calibrated is controlled to move in the direction close to the calibration ball by a preset amplitude to the current pose through inverse kinematics according to the coordinates of the calibration ball in a measurement coordinate system from the standard pose, and the joint contact point of the robot 1 to be calibrated, which moves to the tail end, can be controlled to be at a certain distance obliquely above the calibration ball during the first planning. The method comprises the steps that joint contacts and calibration balls are arranged in the visual field of a binocular camera under the current pose, the coordinates of the joint contacts and the coordinates of the calibration balls under a camera coordinate system are determined according to image information collected by the binocular camera, similarly, a third coordinate conversion relation between a measurement coordinate system and a calibration plate coordinate system can be obtained by combining the coordinates of the joint contacts under the measurement coordinate system, and the coordinates of the calibration balls under the measurement coordinate system under the current pose can be determined by combining the coordinates of the calibration balls under the calibration coordinate system with the third coordinate conversion relation. And continuously executing the step of controlling the tail end position of the robot to be calibrated to move to the direction close to the calibration ball by the preset amplitude to the current pose through inverse kinematics according to the coordinates of the calibration ball in the measurement coordinate system until all the angle sensors of the measuring device are in angle change, determining that all the joint contacts are in contact with the calibration ball, collecting the angle value of each angle sensor at the moment and the angle value of each joint of the robot to be calibrated as a group of collected data corresponding to the calibration ball, and finishing one-time data collection.
In the process of collecting a group of collected data corresponding to a calibration ball, if the relative positions of the joint contacts and the calibration ball are deviated, the joint contacts in the visual field are detected to be shielded by the calibration ball through image information collected by the binocular camera, and/or the joint contacts and the calibration ball are collided at incorrect positions, abnormal changes of data of the angle sensor are detected, for example, when the data of the angle sensor is reversely increased, the robot to be calibrated is controlled to return to the previous pose, and the original trajectory planning is adjusted.
After a plurality of groups of collected data are collected, the nominal position and posture of each calibration ball under the base coordinate system are obtained according to a group of collected data corresponding to each different calibration ball, and the robot kinematics model is compensated by combining the relative distance between each calibration ball to complete calibration. The method comprises the steps of constructing a distance square error model by combining nominal poses of all calibration balls under a base coordinate system and relative distances among all calibration balls, identifying conversion relation errors between a measurement coordinate system and a terminal coordinate system by using a parameter identification algorithm, compensating the conversion relation errors into a robot kinematic model, and completing calibration.
What has been described above is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiment. It is to be understood that other modifications and variations directly derivable or suggested by those skilled in the art without departing from the spirit and concept of the present invention are to be considered as included within the scope of the present invention.
Claims (8)
1. A contact type industrial robot automatic calibration system based on binocular vision comprises a robot to be calibrated, and is characterized by comprising an upper computer, a measuring device, a calibration frame and a binocular camera;
the measuring device is fixed at the tail end of the robot to be calibrated and comprises a plurality of angle sensors, a measuring rod of each angle sensor is fixed with a finger-shaped joint, the other end of each finger-shaped joint is provided with a joint contact, each finger-shaped joint forms a mechanical paw structure, and a measuring coordinate system is established by taking the vertex of one angle sensor as an origin; the binocular camera is fixed at the tail end of the robot to be calibrated, and at least one joint contact always exists in the visual field of the binocular camera;
the calibration frame is arranged in the operation range of the robot to be calibrated, the calibration frame comprises a calibration plane plate and a vertical frame on the calibration plane plate, a plurality of calibration balls are fixed on the vertical frame, a preset calibration pattern is arranged on the calibration plane plate, and a calibration plate coordinate system is established by taking one vertex of the calibration plane plate as an origin;
the upper computer is connected with the robot to be calibrated, each sensor in the measuring device and the binocular camera, and the calibration method of the robot to be calibrated by the upper computer comprises the following steps:
establishing a robot kinematics model, determining a third coordinate conversion relation between a measurement coordinate system and a calibration plate coordinate system by using joint contacts in a binocular camera visual field and a preset calibration pattern of a calibration frame under a standard configuration of the robot to be calibrated, controlling the robot to be calibrated to move to enable the joint contacts to approach the calibration balls by adopting sectional trajectory planning according to the coordinate of the calibration balls under the calibration plate coordinate system and the third coordinate conversion relation based on reverse kinematics and until the joint contacts all contact the calibration balls, and acquiring the angle value of each angle sensor and the angle value of each joint of the robot to be calibrated as a group of acquisition data corresponding to the calibration balls;
and obtaining the nominal pose of each calibration ball under the base coordinate system according to a group of acquired data corresponding to each different calibration ball, and compensating the robot kinematic model by combining the relative distance between each calibration ball to finish calibration.
2. The system of claim 1, wherein controlling the robot to be calibrated to move to make the joint contact point approach to the calibration ball by using segmented trajectory planning comprises:
when the robot to be calibrated is in the standard pose, each joint contact and a preset calibration pattern on the calibration frame appear in the visual field of the binocular camera, the coordinates of the joint contacts and the top point of the calibration plane plate under a camera coordinate system are determined according to image information collected by the binocular camera, and the coordinates of the joint contacts under a measurement coordinate system and the coordinates of the calibration ball under the calibration coordinate system are combined to determine the coordinates of the calibration ball under the measurement coordinate system under the standard pose;
controlling the tail end position of the robot to be calibrated to move towards the direction close to the calibration ball by a preset amplitude to the current pose through inverse kinematics according to the coordinates of the calibration ball under the measurement coordinate system, determining the coordinates of the joint contact and the calibration ball under the camera coordinate system according to the image information acquired by the binocular camera under the current pose, and determining the coordinates of the calibration ball under the measurement coordinate system under the current pose by combining the coordinates of the joint contact under the measurement coordinate system and the coordinates of the calibration ball under the calibration coordinate system;
and re-executing the step of controlling the tail end position of the robot to be calibrated to move to the direction close to the calibration ball by a preset amplitude to the current pose through inverse kinematics according to the coordinates of the calibration ball in the measurement coordinate system until all the joint contacts are determined to be in contact with the calibration ball when all the angle sensors of the measuring device have angle changes.
3. The system according to claim 2, wherein during the process of collecting a set of collected data corresponding to one calibration ball, if it is detected that the joint contact points in the field of view are blocked by the calibration ball through the image information collected by the binocular camera and/or abnormal change of the data of the angle sensor occurs, the robot to be calibrated is controlled to return to the previous pose.
4. The system of claim 1,
each finger joint in the measuring device comprises a plurality of joint sections connected through middle joints, a spring is arranged at each middle joint to connect two adjacent joint sections, and the relative position of each joint section is kept unchanged in a natural state; when the finger joint is subjected to the external force action of the calibration ball and exceeds the elastic force action of the spring, the joint section overcomes the elastic force action of the spring and rotates around the middle joint relatively.
5. The system of claim 1, wherein the calibration frame has the predetermined calibration pattern of a predetermined area at each vertex of the calibration planar plate.
6. The system of claim 1, wherein the calibration frame is provided with at least four calibration balls on both sides of the stand and on a side of the stand facing the robot to be calibrated.
7. The system of claim 1, wherein at least two of said calibration racks are included in said system.
8. The system according to any one of claims 1-7, wherein said compensating said robot kinematics model in combination with the relative distance between the respective calibration balls performs a calibration comprising:
and constructing a distance square error model by combining the nominal poses of all the calibration balls under the base coordinate system and the relative distances among all the calibration balls, identifying and obtaining a conversion relation error between a measurement coordinate system and a terminal coordinate system by using a parameter identification algorithm, and compensating the conversion relation error into the robot kinematics model.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110855774.2A CN113510708B (en) | 2021-07-28 | 2021-07-28 | Contact industrial robot automatic calibration system based on binocular vision |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110855774.2A CN113510708B (en) | 2021-07-28 | 2021-07-28 | Contact industrial robot automatic calibration system based on binocular vision |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113510708A true CN113510708A (en) | 2021-10-19 |
| CN113510708B CN113510708B (en) | 2021-12-28 |
Family
ID=78068662
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110855774.2A Active CN113510708B (en) | 2021-07-28 | 2021-07-28 | Contact industrial robot automatic calibration system based on binocular vision |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113510708B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114516055A (en) * | 2022-04-07 | 2022-05-20 | 北京信息科技大学 | Mechanical arm non-shutdown real-time calibration method and device based on binocular vision and deep learning |
| CN114523471A (en) * | 2022-01-07 | 2022-05-24 | 中国人民解放军海军军医大学第一附属医院 | Error detection method based on associated identification and robot system |
| CN114798873A (en) * | 2022-04-26 | 2022-07-29 | 广州蓝方自动化设备有限公司 | High-speed punch forming process for pipe joint and integrated equipment thereof |
| CN115229805A (en) * | 2022-09-21 | 2022-10-25 | 北京壹点灵动科技有限公司 | Hand-eye calibration method and device for surgical robot, storage medium and processor |
Citations (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2119769A1 (en) * | 1991-10-11 | 1993-04-15 | Alf Pettersen | Method and system for point by point measurement of spatial coordinates |
| EP0817705A1 (en) * | 1995-03-29 | 1998-01-14 | Asea Brown Boveri Ab | Device and method for calibration of a multi-axis industrial robot |
| CN1838870A (en) * | 2005-03-24 | 2006-09-27 | 山形卡西欧株式会社 | Clamping head of electronic member and installation apparatus thereof |
| CN101149256A (en) * | 2007-11-05 | 2008-03-26 | 中山大学 | Follow-up type measuring mechanical arm calibration method based on distance leash |
| CN102032921A (en) * | 2010-11-12 | 2011-04-27 | 南京航空航天大学 | Automatic calibration method for inclinometer |
| US20120283866A1 (en) * | 2005-10-24 | 2012-11-08 | Biomet 3I, Llc | Methods for placing an implant analog in a physical model of the patient's mouth |
| US20150153149A1 (en) * | 2012-06-22 | 2015-06-04 | Hexagon Technology Center Gmbh | Articulated arm cmm |
| CN104897141A (en) * | 2015-05-21 | 2015-09-09 | 常州华达科捷光电仪器有限公司 | Detection device and laser collimator with detection device |
| CN104908047A (en) * | 2014-03-12 | 2015-09-16 | 发那科株式会社 | Robot control device detecting contact with external environment |
| CN105538345A (en) * | 2016-01-27 | 2016-05-04 | 华南理工大学 | Intelligent mechanical arm based on multiple cameras and positioning and assembling method |
| CN105666490A (en) * | 2016-01-12 | 2016-06-15 | 昆明理工大学 | Calibration system and method of robot |
| CN105698661A (en) * | 2016-03-07 | 2016-06-22 | 安徽电气工程职业技术学院 | Contact type scanning probe for micro-nano three-coordinate measuring machine |
| CN108406771A (en) * | 2018-03-09 | 2018-08-17 | 江南大学 | A kind of plane restriction error model and robot self-calibrating method |
| CN108908333A (en) * | 2018-07-13 | 2018-11-30 | 华中科技大学 | A kind of power position feedback control system for flexible robot |
| CN109676636A (en) * | 2019-03-06 | 2019-04-26 | 南京航空航天大学 | A kind of industrial robot kinematics calibration system and scaling method |
| CN110978059A (en) * | 2019-12-23 | 2020-04-10 | 芜湖哈特机器人产业技术研究院有限公司 | Portable six-axis manipulator calibration device and calibration method thereof |
-
2021
- 2021-07-28 CN CN202110855774.2A patent/CN113510708B/en active Active
Patent Citations (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2119769A1 (en) * | 1991-10-11 | 1993-04-15 | Alf Pettersen | Method and system for point by point measurement of spatial coordinates |
| EP0817705A1 (en) * | 1995-03-29 | 1998-01-14 | Asea Brown Boveri Ab | Device and method for calibration of a multi-axis industrial robot |
| CN1838870A (en) * | 2005-03-24 | 2006-09-27 | 山形卡西欧株式会社 | Clamping head of electronic member and installation apparatus thereof |
| US20120283866A1 (en) * | 2005-10-24 | 2012-11-08 | Biomet 3I, Llc | Methods for placing an implant analog in a physical model of the patient's mouth |
| CN101149256A (en) * | 2007-11-05 | 2008-03-26 | 中山大学 | Follow-up type measuring mechanical arm calibration method based on distance leash |
| CN102032921A (en) * | 2010-11-12 | 2011-04-27 | 南京航空航天大学 | Automatic calibration method for inclinometer |
| US20150153149A1 (en) * | 2012-06-22 | 2015-06-04 | Hexagon Technology Center Gmbh | Articulated arm cmm |
| CN104908047A (en) * | 2014-03-12 | 2015-09-16 | 发那科株式会社 | Robot control device detecting contact with external environment |
| CN104897141A (en) * | 2015-05-21 | 2015-09-09 | 常州华达科捷光电仪器有限公司 | Detection device and laser collimator with detection device |
| CN105666490A (en) * | 2016-01-12 | 2016-06-15 | 昆明理工大学 | Calibration system and method of robot |
| CN105538345A (en) * | 2016-01-27 | 2016-05-04 | 华南理工大学 | Intelligent mechanical arm based on multiple cameras and positioning and assembling method |
| CN105698661A (en) * | 2016-03-07 | 2016-06-22 | 安徽电气工程职业技术学院 | Contact type scanning probe for micro-nano three-coordinate measuring machine |
| CN108406771A (en) * | 2018-03-09 | 2018-08-17 | 江南大学 | A kind of plane restriction error model and robot self-calibrating method |
| CN108908333A (en) * | 2018-07-13 | 2018-11-30 | 华中科技大学 | A kind of power position feedback control system for flexible robot |
| CN109676636A (en) * | 2019-03-06 | 2019-04-26 | 南京航空航天大学 | A kind of industrial robot kinematics calibration system and scaling method |
| CN110978059A (en) * | 2019-12-23 | 2020-04-10 | 芜湖哈特机器人产业技术研究院有限公司 | Portable six-axis manipulator calibration device and calibration method thereof |
Non-Patent Citations (4)
| Title |
|---|
| JUNGWON YOON: "Walking control of a dual-planar parallel robot for omni-directional locomotion interface", 《WALKING CONTROL OF A DUAL-PLANAR PARALLEL ROBOT FOR OMNI-DIRECTIONAL LOCOMOTION INTERFACE》 * |
| 冯昌源: "面向变曲率曲面的自动钻铆垂直精度补偿技术", 《面向变曲率曲面的自动钻铆垂直精度补偿技术》 * |
| 朱岳辉: "测斜仪校准装置的研制与误差补偿研究", 《测斜仪校准装置的研制与误差补偿研究》 * |
| 杨化林: "并联机器人末端轨迹测量系统设计", 《并联机器人末端轨迹测量系统设计》 * |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114523471A (en) * | 2022-01-07 | 2022-05-24 | 中国人民解放军海军军医大学第一附属医院 | Error detection method based on associated identification and robot system |
| CN114523471B (en) * | 2022-01-07 | 2023-04-25 | 中国人民解放军海军军医大学第一附属医院 | Error detection method based on association identification and robot system |
| CN114516055A (en) * | 2022-04-07 | 2022-05-20 | 北京信息科技大学 | Mechanical arm non-shutdown real-time calibration method and device based on binocular vision and deep learning |
| CN114516055B (en) * | 2022-04-07 | 2023-06-06 | 北京信息科技大学 | Real-time calibration method and device for mechanical arm without shutdown based on binocular vision and deep learning |
| CN114798873A (en) * | 2022-04-26 | 2022-07-29 | 广州蓝方自动化设备有限公司 | High-speed punch forming process for pipe joint and integrated equipment thereof |
| CN115229805A (en) * | 2022-09-21 | 2022-10-25 | 北京壹点灵动科技有限公司 | Hand-eye calibration method and device for surgical robot, storage medium and processor |
| CN115229805B (en) * | 2022-09-21 | 2022-12-09 | 北京壹点灵动科技有限公司 | Hand-eye calibration method and device for surgical robot, storage medium and processor |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113510708B (en) | 2021-12-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113510708B (en) | Contact industrial robot automatic calibration system based on binocular vision | |
| RU2746931C2 (en) | Method and device for a pliable working body | |
| US9517560B2 (en) | Robot system and calibration method of the robot system | |
| EP3011362B1 (en) | Systems and methods for tracking location of movable target object | |
| CN106247932B (en) | A kind of online error-compensating apparatus of robot based on camera chain and method | |
| CN107883929B (en) | Monocular vision positioning device and method based on multi-joint mechanical arm | |
| CN111660295A (en) | Industrial robot absolute precision calibration system and calibration method | |
| CN111775146A (en) | Visual alignment method under industrial mechanical arm multi-station operation | |
| Miller et al. | Integration of vision, force and tactile sensing for grasping | |
| CN107650144A (en) | The demarcation calibration system and its method of a kind of industrial robot workpiece coordinate system | |
| US20110087360A1 (en) | Robot parts assembly on a workpiece moving on an assembly line | |
| KR102314092B1 (en) | Calibration apparatus and the method for robot | |
| CN102015221A (en) | A method and a system for determining the relation between a robot coordinate system and a local coordinate system located in the working range of the robot | |
| CN104858870A (en) | Industrial robot measurement method based on tail end numbered tool | |
| RU2466858C1 (en) | Method of control of accuracy of profiled movements of industry robots | |
| CN107214692A (en) | The automatic calibration method of robot system | |
| CN109387194B (en) | Mobile robot positioning method and positioning system | |
| US20200262080A1 (en) | Comprehensive model-based method for gantry robot calibration via a dual camera vision system | |
| CN113211431B (en) | Pose estimation method based on two-dimensional code correction robot system | |
| CN208968469U (en) | Industrial robot repetitive positioning accuracy analysis system | |
| CN113352345B (en) | System, method and device for replacing quick-change device, electronic equipment and storage medium | |
| Liu et al. | Binocular-vision-based error detection system and identification method for PIGEs of rotary axis in five-axis machine tool | |
| TWM530737U (en) | Calibration system of robot | |
| CN106989670B (en) | A kind of non-contact type high-precision large-scale workpiece tracking measurement method of robot collaboration | |
| WO2018043524A1 (en) | Robot system, robot system control device, and robot system control method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |