6 DOF Electromagnetic Locking Gravity Balance Surgery Microscope Rack Design And Research

With the increasing demand for microsurgery,surgical microscope has been widely used as an important surgical device in various microsurgery such as ophthalmology,otolaryngology,neurosurgery,and stomatology.The structure of the surgical microscope frame also affects the ease of operation and flexibility of the surgeon during surgery.Therefore,it is particularly important to have a compact design,ample extension range,convenient and reliable operation,and a surgical microscope frame structure that satisfies different microsurgical deployment methods.The operating microscope racks of companies such as Zeiss,Leica,etc.abroad have developed to a very high level.At present,the domestic production of the surgical microscope frame is limited due to the balance of the balance arm of the frame,and it cannot be applied to the microsurgery requirements of various subjects.At the same time,according to the evolution history and research status of surgical microscope frame,combined with electromagnetic brake and robot technology,a six-degree-of-freedom electromagnetic locking gravity-balanced surgical microscope frame is designed.Due to the high cost of manufacturing operating microscope racks,we need to check the strength of key components of the designed structure to ensure the reliability and feasibility of the surgical microscope rack.In this paper,the rationality of the design is verified by establishing a three-dimensional model of the surgical microscope frame and using the finite element analysis software to analyze the relevant structure.The overall design of the rack was first proposed.According to the design specifications of the rack,the overall configuration of the large rack was determined.The double parallelogram mechanism widely used on palletizing robots and the latest gravity balance structure in foreign countries make the whole The operating microscope can achieve a stable balance during the doctor’s surgery.Then according to the characteristics of the rack,the design parameters of the electromagnetic locking device,such as the inner and outer diameters of the friction plate,the spring and the design and selection of the coil,are determined;a variety of base structures are integrated,and a two-point bottoming stop is designed.The new type of internal stop device that controls the brake and release of the plate adopts the way of increasing or decreasing the weight inside the cavity,which makes the whole surgical microscope frame easy to transport and not easy to roll over.According to the D-H method,the kinematics model of the frame is established and the kinematics analysis is performed on the frame.Firstly,the forward kinematics equation is solved,and the correctness of the positive kinematics equation is verified using the Robotics ToolBox toolbox in Matlab.When analyzing inverse kinematics,unlike the general robotic arm,the rack has a double parallelogram structure.We use the geometric method to analyze flexibly,and then use Monte Carlo method to visually display the working space of the rack in a point cloud diagram.By comparing the traditional balance methods,we can see that the rack has a large working space and can adapt to each Surgery requirements.Using Solidworks already established three-dimensional model of the rack,using Ansys Workbench software to perform finite element analysis on the key components of the rack and the whole machine,the maximum stress and maximum displacement of the balance arm are obtained,and then the four extreme positions of the whole machine are respectively Static analysis validates the reliability of the rack system.Finally,the three adjustable arms of the balance arm can be used to optimize the bending radius,the horizontal length of the two axes,and the wall thickness of the main pull tube in the balance arm.Under the constraints of stress and total displacement,the total mass is reduced,and the optimization effect is obvious.