Purpose

Robot-world calibration, used to precisely determine the spatial relation between optical tracker and robot, is regarded as an essential step for optical-navigated surgical robot system to improve the surgical accuracy. However, these methods are complicated with numerous computation. Therefore, a more efficient method of a robot-world calibration is necessary.

Methods

A fully automatic robot-world calibration was proposed and applied in a surgical robot system for oral implant placement. Making full usage of the movement characteristics of a tandem robot, the least square fitting algorithm was implemented to calculate the relationship between the tool center point of the robot and the robot reference frame, with the robot-world calibration matrix obtained as result.

Results

The experiment was designed to verify the accuracy of the robot-world calibration. The average distance deviation was 1.11 mm, and the average angle deviation was 0.99°. From the animal experiment on the pig maxilla, the entry, apical and angle deviation of the surgical robot system were 1.44 ± 1.01 mm, 1.68 ± 0.76 mm, 1.01 ± 1.06°, respectively.

Conclusion

The surgical robot system for oral implant placement with our robot-world calibration maintains a high precision. Besides, the operation range of the surgical tool is no longer limited by the visual range of the optical tracking device. Hence, it is unnecessary to adjust the optical tracking device for the planned implant trajectories to different positions and directions.

中文翻译：

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光学导航手术机器人系统中的自动机器人世界校准及其在口腔植入物放置中的应用。

目的

用于精确确定光学跟踪器与机器人之间空间关系的机器人世界校准被认为是光学导航手术机器人系统提高手术准确性的重要步骤。然而，这些方法由于大量计算而变得复杂。因此，需要一种更有效的机器人世界校准方法。

方法

提出了一种全自动的机器人世界标定方法，并将其应用于外科机器人系统中进行口腔植入物放置。充分利用串联机器人的运动特性，实施最小二乘拟合算法，计算出机器人的刀具中心点与机器人参考系之间的关系，得到机器人世界标定矩阵。

结果

设计该实验是为了验证机器人世界校准的准确性。平均距离偏差为1.11mm，平均角度偏差为0.99°。根据猪上颌骨的动物实验，手术机器人系统的进入角，顶角和角度偏差分别为1.44±1.01 mm，1.68±0.76 mm，1.01±1.06°。

结论

借助我们的机器人世界标定功能，用于口腔植入物放置的外科手术机器人系统保持了很高的精度。此外，手术工具的操作范围不再受光学跟踪装置的视觉范围的限制。因此，没有必要将用于计划的植入物轨迹的光学跟踪装置调整到不同的位置和方向。