Evaluation of the effect of manipulator calibration accuracy on the target-reaching accuracy of a robotic surgical navigation system

Abstract

Objective: To evaluate the effect of manipulator calibration accuracy and the geometric arrangement of calibration points on the resulting target-reaching accuracy of a robotic surgical navigation system. Materials and Methods. The study was conducted using an anthropomorphic head phantom equipped with a monocular optical system and a REDS-C10 collaborative robotic manipulator integrated with the Autoplan surgical navigation system. Seven calibration configurations were established using different combinations of calibration points, varying in number and spatial distribution across the calibrator planes. For each configuration, three calibration conditions were investigated: standard calibration (without error), calibration with a 0.5-mm error in the specified calibration needle length, and calibration with an artificially introduced error in determining the positions of the calibration points. Each experimental condition was repeated five times. Positioning accuracy was assessed based on the mean deviation of the robotic manipulator flange from the specified trajectory. Results. Introducing errors into the calibration parameters resulted in an increase in positioning deviation compared with standard calibration. The most pronounced effect was observed for errors in determining the positions of the calibration points: the relative increase in deviation for configurations C, E, and F was 384.9%, 179.4%, and 218.3%, respectively. Introducing an error in the specified calibration needle length resulted in an increase in deviation ranging from 42.4% to 131.1% for configurations A–F. The most balanced results were obtained for configuration B, for which the increase in deviation was 42.4% with an error in needle length and 56.3% with errors in determining the calibration point positions. Conclusion. The results demonstrate the influence of calibration quality on the positioning accuracy of the robotic manipulator. Errors in determining the positions of the calibration points had a more pronounced effect on the resulting deviation than errors in the specified calibration needle length. Correct calibration and the reliability of the parameters determined during the calibration procedure are important prerequisites for accurate and safe operation of the robotic surgical system.