Design Of Wire-driven Flexible Surguical Robot System

Minimally invasive surgery has been widely used in the past decades due to its low cost,less pain,fast recovery and other advantages.Compared with the traditional minimally invasive surgery,the application of robotic technology in minimally invasive surgery has brought more accurate and intuitive humancomputer interaction interface,as well as the ability to operate miniature instruments remotely.However,the current surgical robots have high requirements on the technical level of doctors and expensive materials to consume.Meanwhile,most surgical instruments are rigid and difficult to complete the surgery in the curved cavity channels such as nasal cavity,oral cavity and abdominal cavity,which greatly reduces the flexibility of the surgical instruments.Therefore,the development of flexible minimally invasive surgery machine personnel with small size,flexible frame and flexible path is the current development demand and trend.In view of the problems brought by the current surgical robots,this paper proposed a new type of line-driven flexible minimally invasive surgery robot based on the previous generation of robots in laboratory.According to the number of degrees of freedom,the working space range and requirements of surgical robots,dimensions of joints of the surgical robot and the overall structure were designed and optimized.The drive system was changed into a combination of a high coding rate servo motor and a micro linear module,which greatly improved motion and control accuracy.The kinematics analysis of the designed robot was carried out,and the normal and inverse kinematics equations were derived respectively.Based on the kinematics equation,the robot's drive control system design and drive algorithm programming were completed,and the control of circular and linear motion of the end actuator were also achieved.MATLAB was used in simulation,and the experimental comparison verified the motion accuracy and space adaptability of robotic arms.Since the flexible surgical robot used in surgery requires precise and reliable motion control and accurate real-time shape reconstruction as feedback for the control system to perform precise operations,this paper proposed an end-tracking and shape rebuild method of line-driven surgical robot based on electromagnetic positioning system.A magnetic induction coil or a small permanent magnet was fixed at the end of the robot,and the magnetic field can be perceived by the electromagnetic tracking system.The direction and position of the end can be obtained by the magnetic tracking algorithm,and the real-time shape of the robot can be estimated by homogeneous transformation matrix based on the shape reconstruction algorithm of Bezier curve.And the closed-loop motion control of robots can be realized by analyzing shape and pose information in the map of the computer display interface.