面向心脏微创消融手术的连续体机器人关键技术研究

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题名	面向心脏微创消融手术的连续体机器人关键技术研究
作者	高安柱
学位类别	博士
答辩日期	2017-05-26
授予单位	中国科学院沈阳自动化研究所
授予地点	沈阳
导师	王志东 ; 刘浩
关键词	构型创成力学建模结构优化力感知精准操控
其他题名	Research on Key Technologies of Continuum Robots for Minimally Invasive Cardiac Catheter Abaltin Surgery
学位专业	机械电子工程
中文摘要	心律失常引发的心脏性猝死患者逐年增加，如果不能及时接受治疗，则可引发心肌梗死和中风，直接导致死亡。经导管的心脏射频消融手术是该类疾病的主要临床治疗手段，其作为典型的心脏微创介入手术，相对于传统的开放手术具有创伤小、恢复快、术后复发率低等优点。传统的基于柔性导管的心脏射频消融手术存在一些临床问题严重制约了其发展，主要包括消融靶点无法准确定位、消融能量的施加难以掌握、消融路径形状的连续性无法保证、消融热损伤区域的形态不可控等问题。为了解决上述问题，本文在国家自然科学基金的资助下，针对连续体机器人构型创成及优化、精确力学建模、精确力感知和精准操控等关键技术进行深入研究。提出了面向心脏微创消融手术的交叉丝驱动的弹簧骨架式连续体机器人和自接触式连续体机器人；对连续体机器人建立了基于贝塞尔曲线拟合的运动学模型，并分析和讨论了各自的运动特性；提出了针对受限空间的连续体机器人靶点搜索算法，对受心腔约束环境下的自接触式连续体机器人的靶点可达性进行研究；通过实验和仿真验证了所提出的自接触式连续体机器人构型的有效性。提出了考虑驱动耦合和离散摩擦交互的丝驱动连续体机器人通用力学模型。采用Cosserat梁作为梁理论模型；建立了考虑驱动丝与柔性骨架之间耦合作用的驱动耦合模型；建立了单点交互的摩擦模型，并扩展至多点交互的离散摩擦分布模型，同时考虑了驱动力加载的历史相关性对模型的影响。建立了弹簧骨架式连续体机器人的力学模型，开展了多次加载实验验证了所提出模型对描述历史相关的驱动力作用下的形状的精确性。针对槽式骨架式连续体机器人，提出了基于柔性杆和刚性杆的分块策略，建立了柔性杆的力学模型，并综合刚性杆来描述连续体机器人变形特性，开展实验验证了力学模型的有效性。针对自接触式连续体机器人，建立了描述自接触和驱动力耦合的力学模型，开展实验验证了该力学模型的有效性。提出了面向任务的自接触式连续体机器人结构优化方法，解决了在受限环境下的连续体机器人结构优化问题。基于上述提出的靶点搜索算法，以受限环境以及连续体机器人自身弯曲特性作为约束条件，以连续体机器人远端切向量与消融靶点法向量最垂直为优化目标，对连续体机器人非对称自接触结构布置及参数开展了寻优。以左心房内环肺静脉消融手术为案例，开展仿真计算实现了全部靶点可达情况下的目标函数最优。研究了面向心脏射频消融手术的导管远端力感知技术。设计了基于并联柔性铰链和布拉格光纤光栅（FBG）的三维力传感器，保证了各个方向的应变范围和分辨率在同一数量级；应用基于梁理论的分析方法和有限元方法来验证了该弹性体的有效性；提出了线性和非线性的三维力解耦算法，前者采用基于欧拉-伯努利梁理论描述了外力和应变的线性关系，并应用最小二乘法求解多元线性回归矩阵描述了FBG应变与三维力的映射；后者采用有监督式的机器学习算法中的支持向量回归来获得了多输入输出之间的非线性映射。实验验证了两种解耦算法的可行性，实验结果表明了非线性解耦算法实现了各方向上<1g的分辨率和1%的预测精度。提出了基于逆运动学和逆力学的自接触式连续体机器人精准操控方法。建立了连续体机器人控制平台，实现了自接触式连续体机器人的弯曲、输送和旋转三个可控自由度。建立了主手手柄和连续体机器人远端点之间的映射关系，采用逆运动学来求解连续体机器人的旋转自由度，并采用逆力学来求解弯曲平面内的运动。实现了在图像引导下的主手对远端点的精准操控，并设计了轨迹跟踪实验验证了对给定轨迹的跟踪精度。综上所述，本文面向心脏微创消融手术，针对连续体机器人的构型创成、精确力学建模、面向任务的结构优化、远端力感知以及精准操控等关键问题进行深入研究，通过仿真和实验验证了所提出的设计或方法的可行性。本文提出的构型及优化方法、力学建模方法、感知技术和控制方法等为提升心脏消融手术的机器人化操作奠定了理论基础，对连续体机器人在类似的受限腔内手术的应用和研究提供了理论依据，这些技术也为更广泛的机器人化手术操作的发展奠定了理论基础。
英文摘要	Heart arrhythmia leads to the increased amount of death year by year. If the patient is not cured immediately, it will cause the myocardial infarction and stroke, even the death. The radiofrequency catheter ablation is the main treatment for this disease, because it has the advantages of less trauma, fast recovery, and low recurrence when compared with the open surgery. Traditional radiofrequency catheter ablation using the continuum robot as the catheter still has some limitations, such as the difficulty to position the target point, uncontrollable transmission of ablative energy, discontinuous ablation line, and uncontrollable size of ablative lesion, etc. To overcome the limitations, this work is done under the national natural science foundation, which focuses on the structure generation and optimization, kinematics, mechanical model, accurate force sensing technology, and precise control. Two types of continuum robots for the cardiac surgery are developed, including a cross helical tendon actuated continuum robot with the spring as the backbone, and a continuum robot with contact aided mechanism. Kinematics based on Bezier interpolation is proposed to analyze and discuss their characteristics. The path exploration in the confined workspace is proposed to validate the effectiveness and reachability of the developed continuum robots. Finally, the simulation results and experimental results are validated. A general mechanical model integrated with actuation and discrete friction is proposed. The beam theory is based on the Cosserat rod theory; the actuation coupling model considers the interaction between the actuation tendon and deformable body, where the interaction applies the normal force and friction force to the deformable body as the boundary conditions; the model at single contact point is proposed, then is extended to describe the multiple contact points with history dependent characteristics. A mechanical model for the continuum robot with the spring as the backbone is built, and the multiple loading/unloading procedure is carried out to validate the effectiveness of the proposed mechanical model under the history dependent loads. The partition method is proposed to divide the backbone as the flexible links and rigid links for the continuum robot with the compliant joints, then the mechanical model is built by integrated the deformation of flexible links and the kinematics of rigid links, finally results demonstrate the effectiveness of the mechanical model. The mechanical model considering the self-contact is proposed to describe the deformation of the continuum robot with contact aided mechanism, finally the experimental results validate its effectiveness. Based on the mechanical model integrated with the actuation and friction, the task oriented optimization method is proposed to optimize the structure of continuum robot in the confined workspace. The method is based on the proposed path exploration algorithm, which is integrated with the constraint from the confined workspace and the continuum robot itself, and defines the maximal relative angle as the optimized object. Finally, simulation results demonstrate the optimized structure of the continuum robot and its full reachability for all the targets. The 3DOF force sensing technology is proposed specifically for cardiac ablation surgery. We design a tri-axial force sensor with parallel flexure hinges to general the strains sensed by the fiber Bragg grating sensors. The proposed mechanism integrated with parallel flexure hinges is capable of providing an excellent lateral and axial stiffness to guarantee the force range and resolution with the same order of magnitude at each direction. The analytical method is used to design a suitable stiffness configuration, and finite element method is used to validate the design. The model based and model-free methods are adopted to decouple the lateral and axial force components. The former adapts the Euler-Bernoulli beam theory to decouple the linear relationship between the strains from fiber Bragg grating sensors and external contact force; the latter adapts the supervised machine learning method - support vector regression to build the relationship between the multiple inputs and outputs. Experiments validate that two decoupling methods are effective and the nonlinear method accomplishes<1g resolution and <1% rms accuracy. An accurate control method based on inverse kinematics and inverse statics of the continuum robot with contact aided compliant mechanism are proposed. A platform is built, which accomplishes the bending/unbending, translation and rotation of the continuum robot. The mapping between the master joystick and continuum robot is built, the inversed kinematics is used to calculate the rotation and the invese statics is used to calculate the motion in the bending plane. Finally, the master slave control based on inverse solution and electromagnetic feedback is accomplished. Also, experiments of trajectory tracking is implemented to demonstrate the effectiveness. In conclusion, this paper focuses on the taks toward the cardiac catheter ablation, and mainly studies on the structure generation, mechanical model, task oriented structure optimization, force sensing technology and accurate control, and simulation and experiments are implemented to validate the effectiveness of the proposed designs or methods. The paper not only establishes the foundation for the robotic implementation for the cardiac catheter ablatoin surgery, but also provides a theoretical reference for the similar applications and works of the continuum robot working in the confined anatomy, therefore laying a theoretical foundation for the development of robotic surgery.
语种	中文
产权排序	1
内容类型	学位论文
源URL	[http://ir.sia.cn/handle/173321/20564]
专题	沈阳自动化研究所_机器人学研究室
推荐引用方式 GB/T 7714	高安柱. 面向心脏微创消融手术的连续体机器人关键技术研究[D]. 沈阳. 中国科学院沈阳自动化研究所. 2017.