Study On Multi Target Magnetic Positioning Technology

One of the features of modern medical surgical operation is minimally invasive treatment.Although the existing surgical navigation system development has been relatively mature in all aspects,the problems encountered by surgeons during the actual operation are not well solved.The operation navigation system is easy to be affected by the occlusion of objects,the surrounding light and the mirror reflection of metal objects,leading to the loss of tracking data,serious errors and false targets.Minimally invasive surgery,location tracking,and in vivo tracking in particular,requires a wireless passive localization system.Compared with traditional surgical navigation system,magnetic positioning tracking system has the advantages of small target size,no line of sight constraint and high accuracy.Therefore,we designed a multi-target magnetic positioning system,and developed a prototype to carry out experimental research.By modeling the cylindrical magnet,the magnetic models have been compared and analyzed.We present a sensor layout strategy based on grid method and its optimization method for better performance.We have built a sensor array for magnetic positioning system based on the results.Through the application of multi-target magnetic positioning technology,6Do F positioning and real-time localization and navigation of micro robot are realized.The 6Do F positioning is realized by combining two identical magnets with opposite magnetic moment direction as the tracking target.By defining pose parameters based on the position and orientation constrains of the two magnets,6Do F pose information can be estimated with optimization method.The experimental results shows the proposed method is feasible.In order to obtain better positioning effect,the above 6Do F positioning method is improved.Two magnets of different sizes with opposite magnetic directions have been combined together to serve as the tracking target.By applying the constraint multi-magnet tracking algorithm,we can achieve a 6Do F positioning of the target.The feasibility of the proposed method is verified by the experimental results The real-time positioning and navigation of the micro robot is realized by taking the active magnet and the driven magnet as the positioning target.With the proposed actuation method,4Do F drive(2Do F position and 2Do F orientation)and 5Do F positioning(3Do F position and 2Do F orientation)can be achieved on the experimental platform.The effectiveness of the proposed method is verified by navigation simulation experiments and driven fixed-point experiments.