Research On Force Modelling And Cutting Mechanism In Robotic Bone Milling

In orthopedic surgery,it is inseparable from the cutting of bones.Compared with traditional orthopedic surgery,orthopedic robots have the advantages of minimal innovation,precision and individualization.However,in the clinical process,the problems of osseointegration and poor bone remodeling caused by random cutting parameters,excessive cutting force,bone residual and incomplete surface morphology make the success rate and postoperative recovery effect greatly reduced.Therefore,based on the experiment of robotic bone milling and 3D finite element simulation of bone milling,the particle swarm optimization neural network algorithm is applied to the force modeling of robotic bone milling,and the preoperative planning prediction system is established.The cutting mechanism of chip formation,surface quality and anisotropy of the bone material is investigated afterwards.The details are as follows:(1)Analysis of research status and difficulties.Summarizing the research status of bone cutting at home and abroad.The research on finite element simulation,force modeling and mechanism of bone cutting process is summarized.In the clinical process,the problems of osseointegration and poor bone remodeling caused by random cutting parameters,excessive cutting force,bone residual and incomplete surface morphology restrict the development of orthopedic robots greatly.(2)Robotic orthopedic surgery and bone material characteristics.A detailed analysis of the orthopedic robotic system and the osteotomy process during surgery is performed.The amount of osteotomy volume,shape and time during surgical osteotomy is analyzed in detail.The biological properties,geometric properties and mechanical properties of bone material are also analyzed in detail.(3)Three-dimensional finite element simulation and experimental verification of bone milling process.The bone milling process is simulated using DEFORM-3 D finite element simulation software.The problems of three-dimensional modeling of milling bur and bone workpiece,constitutive model of bone material,meshing of tool and workpiece,separation criteria for chips and bone workpiece,as well as friction contact model are analyzed in detail.The bone milling force is obtained during the simulation and is verified by machine tool experiments.(4)Experimental study of robotic bone milling.Using the special milling bur of orthopedic robot,the influence of cutting parameters on the force during robotic bone milling process is studied by the single factor variable method,which provides the data foundation for force modeling in the subsequent bone milling process.(5)Research on force modeling and prediction system of robotic bone milling.The particle swarm optimization algorithm is used to optimize the initial weight and threshold of BP neural network to establish the algorithm of particle swarm optimization neural network.The algorithm is applied to the force modeling of robotic bone milling.Based on the algorithm,the preoperative planning and prediction system is established using Matlab GUI.(6)Research on the mechanism of robotic bone milling.Based on a large number of experimental statistical studies,chip morphologies in the process of robotic bone milling are classified.The single factor variable method is used to analyze the influence of cutting parameters on chip morphology and surface quality during robotic bone milling,and then analyzing the relationship between chip morphology and surface quality.The effects of bone material anisotropy on cutting force,chip morphology and surface quality during robotic bone milling are analyzed.