How to troubleshoot Hand-Eye Calibration

Before troubleshooting, ensure you have followed the best practices and recommendations in:

• How to get Good Dataset for Hand-Eye Calibration

• How to get Good Quality Data on Zivid Calibration Object

• Cautions and Recommendations for Hand-Eye Calibration

If that does not resolve your issue, check out the following troubleshooting guides.

Troubleshooting Guides

For issues while running the hand-eye calibration, please see:

• Failed to detect Zivid calibration board

• OSError: [WinError 127] The specified procedure could not be found

For issues with hand-eye calibration results, please see:

Matrix	Residuals	Projection	Touch Test	Tutorials
Bad	Bad	Poor/Bad	Unsafe	Calibration Board Moved Robot Poses in m, Point Clouds in mm No Rotations, only Translations in Dataset Wrong Rotation Convention Manual Robot Pose Typos Wrong Hand-Eye Configuration
Reasonable	Good/Marginal/Bad	Poor/Bad	Bad	Loose or Sagging On-Arm Mount Vibrating Calibration Board Manual Robot Pose Typos Bad Robot Calibration (DH parameters) Bad TCP Calibration
Reasonable	Good/Marginal	Good/Poor	Marginal	Manual Robot Pose Typos Bad Robot Calibration (DH parameters) Bad Robot Calibration (Mastering/Zeroing) Bad Dimension Trueness (No Infield Correction) Camera Outside Working Distance Bad TCP Calibration
Reasonable	Good	Good	Good → Bad	Hand-Eye Calibration Lost after Mild Crash

Interpretation of Evaluation Criteria (Bad, Marginal, Good, etc.)

The evaluation criteria are defined as follows:

• Unsafe: The hand-eye calibration results suggest a risk of collision during the touch test. Do not proceed with the touch test until the underlying issues are resolved.

• Bad: The hand-eye calibration results are poor and indicate significant issues with the calibration process. The touch test is likely to fail, and there may be a risk of collision. Address the underlying issues before attempting the touch test.

• Marginal: The hand-eye calibration results are acceptable but not ideal. The touch test may show some deviations, but it is generally safe to proceed. Consider improving the calibration process for better results.

• Good: The hand-eye calibration results are excellent, with minimal deviations expected in the touch test. It is safe to proceed with confidence in the accuracy of the calibration.

Check the definitions below, then use the table to find the troubleshooting guide that matches your hand-eye calibration results.

Hand-Eye Transformation Matrix Quality

• Bad - Values are clearly unrealistic. The matrix does not match what you would expect from rough measurements or the system’s CAD geometry.

• Reasonable - Values appear physically plausible and align with approximate measurements or the CAD model.

Residuals Quality

• Good - ≤ 1 mm translation and < 0.4° rotation

• Marginal - ≤ 3 mm translation and ≤ 1° rotation

• Bad - > 3 mm translation or > 1° rotation

Verification by Projection

• Good - Projection dots fall on the centres of the central checkers; diagonals land in the checker corners.

• Poor - Projection dots fall inside central checkers, but diagonal lines miss the corners.

• Bad - Projection dots fall outside the central checkers.

Touch Test Quality

• Good - ≤ ~1 mm deviation

• Marginal - > ~1 mm and ≤ ~3 mm deviation

• Bad - > ~3 mm deviation

• Unsafe - Touch test not performed because the matrix, residuals, or projection suggested collision risk.

If you are still having issues, please Contact Us.