A study on development of vibration control gyroscopes for surgical microscopes

本课题研制了一种手术显微镜陀螺振动控制系统。显微镜下的外科手术有时会受到视野振动的严重干扰。这些显微镜通常由一些载体臂支撑，以增强效用。因此，即使是医生或护士在手术室里的日常动作也很容易引起手臂的振动。认为动量交换式振动控制装置适合于这些应用。特别是当频率范围小于10Hz时，陀螺仪执行器也能产生良好的控制效果。根据手术显微镜的典型规格，开发了一套实验CMGs系统。该系统有6个相同的万向架，每个万向架支撑一个直径59mm，厚度10mm的均匀钢盘转子。所有转子的典型旋转频率为3600rpm。这六个万向节组成三对，在每对中，两个万向节由一个圆柱齿轮和一个平行曲柄连接。该框架由直流伺服电机驱动，从而可以独立控制正交三轴的输出转矩。CMGs单元被小型化，安装在臂的自由端附近，重量小于3kg。搭建了显微镜载体臂模型，该模型由一个基本单元和带有三个关节的双臂组成，载体总长1.5m。采用基于PC机的DSP系统进行反馈控制。三个伺服式加速度计与cmg单元一起安装在机械臂的自由端附近。为此重新安排了变增益速度反馈控制，并在MATLAB/Simulink Realtime Workshop环境下开发了它们的框图。实验验证了陀螺仪系统对手术显微镜减振的有效性。

In this research project, a gyroscopic vibration control system for surgical microscope was developed. Surgical operations under microscopes are sometimes seriously disturbed by the vibration of visual fields. These microscopes are usually supported by some carrier arms to enhance the utilities. Thus,vibrations of the arms are easily induced even by usual movements of doctors or nurses in the operating room. It is considered that the momentum-exchange type vibration control devices are suitable for these applications. Especially, gyroscopic actuators yield good control effects even when the frequency range is less than 10Hz. An experimental CMGs system was developed assuming the typical specification of surgical microscopes. This system has six identical gimbals, and each gimbal supports a rotor of uniform steel disk, which is 59mm in diameter and 10mm in thickness. The typical rotational frequency is 3600rpm in all rotors. These six gimbals makes three pairs, and in each pair, two gimbals are connected by a spar gear and a parallel crank. The pair of gimbals are driven by a DC servomotor, thus the output torques around the orthogonal three axes can be controlled independently. The CMGs unit is miniaturized to be attached near the free end of arm, and the weight is less than 3kg. A mock-up of microscope carrier arm was build for the experiments, which consists of a base unit and double arms with three joints, and the carrier is 1.5m in totallength. The PC based DSP system was employed for the feedack control. Three servo-type accelerometers were installed near the free end of the arm together with the CMGs unit. A variable gain velocity feedback control was rearranged for this purpose, and their block diagrams were developed under MATLAB/Simulink Realtime Workshop environment. Thus, the effectiveness of the gyroscopic system for the vibration damping of surgical microscope was experimentally confirmed.