Background and objective

The application of robot technology in fracture reduction ensures the minimal invasiveness and accurate operation process. Most of the existing robot assisted fracture reduction systems don't have the function of bone collision detection, which is very important for system safety. In view of the deficiencies in the research of this field, a broken bone collision detection method based on the slope ratio of force curve was proposed in this paper, which could realize the real-time detection.

Methods

In order to analyze the factors influencing the slope of force curve, a collision mechanical model based on three-element viscoelastic model was established. The effects of four factors on the slope ratio of the force curve were studied based on the mechanical model. The proposed collision detection model was analyzed in detail. By drawing slope ratio curves under various experimental conditions, the universality of the collision detection model was proved; by comparative simulation, the differences between the slope ratio curves before and after optimization were analyzed. The factors that affect the performance of the detection model were also analyzed.

Results

The results of collision experiments show that the increase of moving speed of distal bone and soft tissue mass reduces the slope ratio, while the increase of collision angle increases the slope ratio. In the verification experiment, the minimum main peak of KR_opt curve is 14.16 and the maximum is 220.7, the maximum interference value before the peak is 6.1. When the detection threshold is 10, the model can detect the collision state of the broken bone. It is also proved that after optimization, the model can effectively filter out invalid waveforms and reduce the occurrence of false detections. When a=5 and b=40, the detection model has sufficient stability and a low detection time delay.

Conclusion

This research developed a broken bone collision detection method based on the slope ratio of the force curve. After optimization, the method has good adaptability under a variety of experimental conditions. The collision of broken bones can be judged by setting an appropriate detection threshold. The application of this method in the robot fracture reduction system will improve the safety of the system.

中文翻译：

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基于力曲线斜率的机器人辅助骨折复位骨碰撞检测方法

背景和目的

机器人技术在骨折复位中的应用，保证了微创和准确的手术过程。现有的机器人辅助骨折复位系统大多不具备骨骼碰撞检测功能，这对系统安全非常重要。针对该领域研究的不足，本文提出了一种基于力曲线斜率比的断骨碰撞检测方法，可实现实时检测。

方法

为分析影响力曲线斜率的因素，建立了基于三元粘弹性模型的碰撞力学模型。基于力学模型研究了四个因素对力曲线斜率的影响。详细分析了所提出的碰撞检测模型。通过绘制各种实验条件下的斜率曲线，证明了碰撞检测模型的通用性；通过对比模拟，分析了优化前后斜率曲线的差异。还分析了影响检测模型性能的因素。

结果

碰撞实验结果表明，远端骨和软组织块移动速度的增加降低了斜率，而碰撞角度的增加则增加了斜率。在验证实验中，KR _opt曲线的最小主峰为14.16，最大为220.7，峰前最大干扰值为6.1。当检测阈值为10时，模型可以检测到断骨的碰撞状态。也证明了优化后的模型可以有效滤除无效波形，减少误检的发生。当a = 5 和b = 40 时，检测模型具有足够的稳定性和较低的检测时延。

结论

本研究开发了一种基于力曲线斜率的断骨碰撞检测方法。经过优化，该方法在多种实验条件下具有良好的适应性。断骨的碰撞可以通过设置合适的检测阈值来判断。该方法在机器人骨折复位系统中的应用将提高系统的安全性。