Loschak Paul M, Degirmenci Alperen, Tenzer Yaroslav, Howe Robert D
School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
Proc ASME Des Eng Tech Conf. 2015 Aug;5A. doi: 10.1115/DETC2015-47693.
In this paper we present the design, fabrication, and testing of a robot for automatically positioning ultrasound imaging catheters. Our system will point ultrasound (US) catheters to provide real-time imaging of anatomical structures and working instruments during minimally invasive surgeries. Manually navigating US catheters is difficult and requires extensive training in order to aim the US imager at desired targets. Therefore, a four DOF robotic system was developed to automatically navigate US imaging catheters for enhanced imaging. A rotational transmission enables three DOF for pitch, yaw, and roll of the imager. This transmission is translated by the fourth DOF. An accuracy analysis was conducted to calculate the maximum allowable joint motion error. Rotational joints must be accurate to within 1.5° and the translational joint must be accurate within 1.4 mm. Motion tests were then conducted to validate the accuracy of the robot. The average resulting errors in positioning of the rotational joints were measured to be 0.28°-0.38° with average measured backlash error 0.44°. Average translational positioning and backlash errors were measured to be significantly lower than the reported accuracy of the position sensor. The resulting joint motion errors were well within the required specifications for accurate robot motion. Such effective navigation of US imaging catheters will enable better visualization in various procedures ranging from cardiac arrhythmia treatment to tumor removal in urological cases.
在本文中，我们介绍了一种用于自动定位超声成像导管的机器人的设计、制造和测试。我们的系统将引导超声（US）导管，以便在微创手术期间提供解剖结构和手术器械的实时成像。手动操作超声导管很困难，并且需要大量训练才能将超声成像仪对准所需目标。因此，开发了一种四自由度机器人系统，以自动引导超声成像导管，从而增强成像效果。一种旋转传动装置为成像仪的俯仰、偏航和滚动提供三个自由度。该传动装置由第四个自由度进行平移。进行了精度分析，以计算最大允许关节运动误差。旋转关节必须精确到1.5°以内，平移关节必须精确到1.4毫米以内。然后进行了运动测试，以验证机器人的精度。测量得出旋转关节定位的平均误差为0.28°-0.38°，平均测量的反向间隙误差为0.44°。测量得出的平均平移定位误差和反向间隙误差明显低于位置传感器报告的精度。由此产生的关节运动误差完全在机器人精确运动所需的规格范围内。超声成像导管的这种有效引导将能够在从心律失常治疗到泌尿外科肿瘤切除等各种手术中实现更好的可视化。
