Design And Research Of A Guidance Device For Minimal Invasive Spinal Surgery Based On3-RPS Parallel Mechanism

For spinal diseases such as: spinal deformity, spinal trauma, degenerative decay,etc., the surgical operation is complicated. During the operation, Spinal pedicle screwplacement is a very important procedure. But the surgery is still manual operation bydoctors with their clinical experience at present. So accuracy of operation is greatlyinfluenced by human factors such as tiredness and physiological tremor. All those leadto large deviations of screw implantation even affecting the therapeutic effect. Therefore,the development of high precision robotic spine surgery to improve the safety and thesuccess rate has important theoretical and clinical significance.Firstly, a thorough research and analysis about guidance device has been done. Thework includes kinematics, solution of jacobian matrix, Workspace Analysis. Based onthat, the parallel guidance is designed and3D and2D drawing is drew and parts areprocessing and assembly. The first generation of parallel spinal surgery guidance hasbeen completed. Then the control system is designed. The work includes hardwaresystem design,control interface design and implementation of kinematics algorithm withC++etc..In order to improve the accuracy of parallel mechanisms, it is necessary to proposea calibration algorithm which is esay for engineering applications and can improve theaccuracy of parallel mechanism.For the calibration of the manipulator the paper focuseson the work as follows: firstly, a detailed analysis about various sources of error of3-RPS parallel robot is performed, and the parallel model including those error sourcesis built with the D-H method. Then, a quantitative sensitivity analysis of those errorsources is carried out by Monte-Carlo techniques. According to the sensitivity analysis,a sensitive source of error is determined for establishing calibration model based oninverse kinematics. Finally, CMM is used for calibration of the3-RPS parallel robot,and the experimental results shows the improvement via the calibration. In this paper,3-RPS parallel mechanism calibration method based on coordinate is proposed and itcan easily and effectively improve the accuracy of parallel. It is confirmed withexperiment.