Pre-Calibration Checks for Hand-Eye Calibration

Before checking robot accuracy, first check whether the robot base is firmly installed. If the base is unstable, the robot may shake during motion, affecting repeatability accuracy and the reliability of subsequent robot accuracy checks.

Confirm that robot base installation meets the following requirements:

Inspection method: Move or rotate the robot with large amplitude at 100% speed, and check whether there is obvious shaking of the robot base and body. If yes, secure them according to robot installation requirements.

Before hand-eye calibration, confirm the camera bracket and camera are firmly installed. Perform the following checks:

In Eye to Hand (ETH) scenarios, first install the connector of the calibration board or marker to the robot end flange, then install the calibration board or marker onto the connector. Ensure it is firmly installed and positioned at the center of the camera field of view, and keep it as parallel as possible to the camera imaging plane, that is, keep the calibration board or marker as perpendicular as possible to the Z-axis of the camera coordinate system.

Inspection method: Manually shake the calibration board or marker. If there is no obvious shaking, installation can be considered firm.

In Eye in Hand (EIH) scenarios, you do not need to install the calibration board or marker on the robot end; instead, place it flat at the center of the work surface.

Robot absolute accuracy checks generally require professional equipment such as a laser tracker and calibration software. You need to check robot absolute accuracy yourself or contact the robot manufacturer, and provide a robot absolute accuracy inspection report.

Evaluation of robot absolute accuracy is very complex. Mech-Mind provides only several common qualitative evaluation methods. For details, refer to Check Robot Absolute Accuracy.

If there is a large discrepancy between the simulated robot pose/tool pose in the software and the real robot pose, for example 1 m to 2 m, robot model parameters may be inaccurate and require correction.

For detailed operations, refer to Robot Model Parameter Verification Tutorial.

Hand-eye calibration requires input images without distortion effects. If camera distortion exists, it will affect the correspondence between the camera and robot coordinate systems, and thus affect hand-eye calibration accuracy. Therefore, before hand-eye calibration, ensure the camera has no distortion or that distortion calibration has been completed.

Camera temperature drift can affect image quality and impact camera repeatability and absolute accuracy. Therefore, warm up the camera before hand-eye calibration.