一种并联骨折手术机器人的安全运动控制方法  

Safety Motion Control for a Parallel Fracture Surgical Robot

作　　者：宋轶民[1] 贾殿魁 贺志远[1] 连宾宾[1] 孙涛[1] 姚琦 Song Yimin;Jia Diankui;He Zhiyuan;Lian Binbin;Sun Tao;Yao Qi(Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education,Tianjin University,Tianjin 300350,China;Institute of Orthopedics,The First Medical Centre,Chinese PLA General Hospital,Beijing 100853,China)

机构地区：[1]天津大学机构理论与装备设计教育部重点实验室,天津300350 [2]中国人民解放军总医院第一医学中心骨科,北京100853

出　　处：《天津大学学报（自然科学与工程技术版）》2023年第3期221-231,共11页Journal of Tianjin University：Science and Technology

基　　金：国家重点研发计划资助项目(2018YFB1307805);天津市科技计划资助项目(18PTLCSY00080,20201193).

摘　　要：骨折手术机器人是实现精准微创骨折复位的优势方案.现有骨折复位手术器械存在效率低、精度差、缺乏复位安全策略等问题,难以保证安全高效的治疗.为解决上述问题,本文提出一种并联骨折手术机器人及基于全关节逆解算法的安全运动控制方法.首先,针对该并联机构开展全关节逆解分析.由骨折复位轨迹的离散轨迹点获取机器人末端的位姿,建立机器人机构的闭环矢量方程,以关节转角为未知量整理多元一次方程组,考虑关节间的运动约束通过两条运动链解析求解所有关节转角.其次,设计安全运动控制系统.上位机设置正常、预警及超限3种状态.在机器人运行过程中,由上位机读取复位轨迹离散点的位姿信息,通过全关节逆解模型计算出下一轨迹离散点对应的关节转角并判断运行状态,若超限则发送指令使机器人停止运动,并显示发生危险的关节位置.最后,开展安全运动仿真与实验研究.仿真表明全关节逆解模型可快速计算出全部关节的运动状态并准确进行安全判断.实验结果表明,骨折手术机器人运行过程中,控制系统可及时发现机器人临近危险状态并使机器人停止运动.本文提出的安全运动控制方法无需增设安全检测或保护装置,既保证了骨折手术机器人的轻质便携需求,又保证了安全高效精准的骨折复位治疗.The fracture surgical robot has been recognized as a promising solution to the problems encountered in realizing precise and minimally invasive fracture surgery.Current manual fracture surgical robots have the problems of low efficiency,poor precision and safety control.To solve these problems,a parallel fracture surgical robot is pro-posed,and a safety motion control method is investigated in this study.The proposed safety motion control method is based on the inverse kinematics of all joints.First,the inverse kinematics of all joints is carried out.The discrete trajectory point is derived from the reduction trajectory to formulate the closed-loop vector equation.Considering the motion constraints between the joints,the rotation angles of the joints are solved analytically through two kinematic chains.Then,the safety motion control system is designed.Three states,i.e.,normal,close to danger,and danger,are defined in the host computer.During the operation of the robot,the host computer reads the pose information of the discrete points of the reduction trajectory,calculates the joint rotation angle corresponding to the next discrete trajectory point through the inverse solution model of all joints,and determines the operation state.In the danger state,the controller stops the robot to prevent collisions,and the positions of the joints at risk are shown.Finally,simulations and experiments are conducted to verify the proposed safety motion control method.The simula-tion results show that the inverse kinematics of all joints can rapidly identify the motion states of the robot.The ex-periments show that the control system can efficiently react to the danger and protect the robot from collisions.The merits of the proposed safety control method are twofold:①lightweight and wearable features are assured by not adding sensors or safety mechanisms,and②fracture reduction efficiently and safely prevents collisions.

关 键 词：骨折手术机器人 并联机构 全关节逆解 安全运动控制 

分 类 号：TH122[机械工程—机械设计及理论]