Research On Key Technology Of Soft Manipulator Used For Surgical Robot

Using of a surgical manipulator for Single-port Endoscopic Minimally Invasive Surgery can reduce the fatigue of doctors during operation.With surgical manipulator,doctors can realize more detailed and more complicated operations.The professional ability of doctors can be improved,and the safety of diagnosis and treatment process can be increased.Because of advantages of using medical robotic arms for Single-port Endoscopic Surgery or Natural Orifice Translumenal Endoscopic Surgery,medical R&D personnel has aroused widespread interest in the medical robotic arms.Many medical and scientific research institutions have demonstrated the procurement and R&D of the medical robots.The design and development of such highly integrated surgical robots is a great test for the research and development capabilities of R&D institutions.At the same time,the joint connection method in the system is different from traditional manipulators,which greatly improves the course rating of the manipulator configuration establishment and forward-inverse kinematics models.These key technologies have gradually developed into key research objects in the field of minimally invasive surgical manipulators.Based on the above background,this paper has carried out the research on the key technology of the soft manipulator used for minimally invasive medical robot.Including the system configuration establishment,drive system design,control system,kinematics theory expression,system control parameter inverse solution and other key technology research.First of all,considering the practical operation methods and application scenarios of minimally invasive surgery,the performance indicators of the medical robot system are determined.Then the multi-degree-of-freedom soft manipulator is designed based on the 3D printing processing method.The manipulator is made of silicone-like materials and driven by cable.The state of organs in the body can be observed through a hand-eye camera.At the same time,in view of the scalability for robotic arm with multiple degrees of freedom,the soft robotic arm driven-mechanism is designed to drive up 12 degrees of freedom at most.The drive-mechanism is composed of 12 groups of sub-drive system,which can provide driven force for the medical robot system required.Afterwards,because of high challenge for the soft manipulator’s inverse kinematics parameters resolved,this paper research a control algorithm for the three-segment soft manipulator with cable-driven.The kinematic model of the manipulator system is proposed which derived by using the segmented constant curvature.Then a control algorithm that can solve the inverse kinematics of the system effectively is proposed.Through the inverse kinematics algorithm proposed in the article,the point-to-point inverse kinematics can be solved quickly in the working space of the soft manipulator,so as to realize the motion of soft manipulator in the specified trajectory.A linear-motion simulation and a-arc motion simulation of the soft manipulator are used to prove the feasibility of the proposed algorithm.The algorithm can realize the inverse kinematics solution of the soft manipulator in working space.Then,considering the system model established by the traditional piecewise constant curvature method always has many assumptions,motion parameters of the manipulator cannot be expressed accurately.The corresponding algorithm method cannot control the software manipulator accurately.In response to the above problems,this paper proposes an algorithm combining geometric segmentation and Back Propagation Neural Network(BPNN)used to soft manipulator kinematics parameter solution.The system model established to collect the training set data.Through the training and learning of BPNN,the mapping relationship between driving parameters of the manipulator and position of the arm is established.The accuracy and feasibility of the algorithm are verified according to an algorithm simulation.Finally,according to the application scenarios and performance test requirements of the system in this article,the experimental process of the robotic arm is introduced,including the robotic arm load capacity experiment,the bendable angle experiment,the two-degree-of-freedom joint motion experiment,and the spatial random point scanning motion experiment,Three-segment manipulator motion experiment and narrow space simulation visit experiment.These experiments have tested the performance of the manipulator system exactly.Experiments proved the good performance of designed manipulator system and the feasibility of algorithms.