DOBOT CRA Series Automatic Calibration
This topic introduces the process of automatic calibration via Standard Interface communication between the DOBOT CRA Series robot and Mech-Mind Vision System.
Preparation before Calibration
Make preparation before calibration according to the camera mounting method.
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If the camera is mounted in the Eye to Hand method, see Preparation before Calibration in Automatic Calibration in the Eye-to-Hand Setup.
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If the camera is mounted in the Eye in Hand method, see Preparation before Calibration in Automatic Calibration in the Eye-in-Hand Setup.
Pre-calibration Configuration
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Open Mech-Vision, and click the Camera Calibration button in the toolbar. The Configuration before Calibration window will be prompted.
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Confirm that the checks are performed, click I’ve finished all checks, and then click Next.
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In the Select how to calibrate window, select the New calibration radio button, and then click the Next button.
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In the Select calibration task window, select Hand-eye calibration for listed robot from the drop-down list box, click the Select robot model button to select the robot model used by the project, and then click the Next button.
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In the Select camera setup window, select the camera mounting method in this project, and then click the Next button.
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In the Calibration method and robot control window, select Automatic and Standard Interface, and then click the Calibrate button to go to the Calibration window.
Calibration Procedure
Conduct calibration according to the camera mounting method.
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If the camera is mounted in the Eye to Hand method, see Calibration Procedure in Automatic Calibration in the Eye-to-Hand Setup.
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If the camera is mounted in the Eye in Hand method, see Calibration Procedure in Automatic Calibration in the Eye-in-Hand Setup.
Precautions
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When you proceed to the third calibration step (connecting the robot) and you click Start interface service button in the Connect the robot window, the button will change to Waiting for the robot to connect.... If the interface service is already started, you do not need to perform this operation.
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When the button displays Waiting for the robot to connect..., perform the following steps on the robot side. Then, continue the calibration in the software.
1. Teach Calibration Start Point
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In the upper-right toolbar of the main interface of DobotStudio Pro, select Jog to move the robot to a proper calibration start position. Set User coordi... to 0 and Tool coordi... to 0.
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Select . On the Points tab, select Add point (⑥) to record the current position of the robot.
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Return to the script programming interface of DobotStudio Pro, find the mm_auto_calib function in the global.lua file, and then modify the parameter values of P1 in the Go command to the values of the recorded current position.
2. Run Calibration Program
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Call the mm_auto_calib() function in the src0.lua file and select Run to run the calibration program.
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When, in the Configuration window in Mech-Vision, the current status changes to connected and the button Waiting for the robot to connect changes to Disconnect robot, click Next. Next, proceed to the fourth step of the calibration process (i.e. setting the movement path).
Change the Extrinsic Parameter File
If the camera’s extrinsic parameter file has been used by a Mech-Vision project, you need to change the extrinsic parameter file used by the Mech-Vision project to a new one after you finish the hand-eye calibration.
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Select the Capture Images from Camera Step.
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In the Step Parameters panel, click
of the Calibration Parameter Group parameter, and select the newly calibrated extrinsic parameter file.
Calibration-Related Status Codes
During automatic calibration via Standard Interface communication, the vision system returns data together with the status code to the robot. Status codes, which are categorized into error codes and normal status codes, indicate the command execution status. Calibration related status codes are listed in the tables below.