Design And Optimize Of Six-degree-of-freedom Parallel Spine Surgery Robot

Surgical robots are gradually entering the operating room to assist doctors.Among a variety of surgical robots,orthopedic surgical robots can help doctors reduce a lot of physical labor,provide precise positioning,and improve the safety of surgery.The spine surgery robot is a difficulty in orthopedic surgery robots.Spine surgery requires robots to have high accuracy,fix the guiding device during spinal surgery,and avoid harm to the patient’s nervous system.In order to provide high accuracy,a typical six-degree-offreedom parallel robot Stewart platform is selected as the robot body.Compared with the series robot,the parallel robot has better stiffness and positioning accuracy.In order to design a six-degree-of-freedom parallel robot with better performance,the optimization design method is used to optimize the mechanism parameters of the parallel robot.Optimal design needs to study the basic principles of parallel robots first.In the kinematics of parallel robots,inverse kinematics can directly give an analytical solution,while forward kinematics is a problem to be solved.Under the traditional homogeneous transformation matrix method,the forward kinematics solution of the parallel robot needs to solve the coupled high-order equations.The coupling mainly lies in that the three posture parameters need to be transformed into a rotation matrix of nine parameters under the homogeneous matrix method.The quaternion method can improve the coupling of the homogeneous matrix in the rotation matrix.The three posture parameters are represented by the quaternion of four parameters.Furthermore,the three-dimensional rotation of rigid body described by dual quaternion can more concisely describe the three-dimensional motion of rigid body and eliminate the ambiguity of expression compared with the homogeneous matrix method.Dual quaternions describing the three-dimensional motion of rigid bodies have been applied in many fields.The kinematics of the parallel robot is deduced using dual quaternion,and its form is more concise than homogeneous matrix.The workspace of parallel robots is still mainly solved by numerical methods,but only the reachable position workspace can be obtained.Try to propose a generalized workspace,which integrates the reachable position workspace and the reachable posture workspace of the parallel robot to describe the workspace better of the parallel robot.Dynamic analysis is also essential in the control of parallel robots,which can determine the driving force of each joint under a given load.After the mechanism parameters of the parallel robot are basically determined,the tolerances need to be allocated reasonably under the condition of ensuring accuracy.Optimal design is different from traditional design methods.Iteratively optimizes mechanism parameters by setting optimization goals and using evolutionary algorithms.This paper takes multi-objective optimization as the direction,takes the generalized workspace integrated position space in the workspace,and converts multi-objective optimization into single-objective optimization.Using particle swarm algorithm,the result can be directly optimized with a small amount of input.In this way,the parameters of the parallel mechanism are optimized,and certain results are obtained.