脊柱手术机器人

针对脊柱手术中的椎弓根钉内固定术,为克服医生操作手术时定位精度难以保证、长时间手术易疲劳等问题,设计了一套脊柱手术机器人系统用于辅助实施椎弓根钉内固定术。机器人为5自由度,充分考虑手术机器人对安全性和工作空间有效覆盖的要求,进行了构型设计,并完成了相应的机器人运动学分析。控制系统是由图像导航下的主动控制和基于力传感器的被动拖拽控制两个模式进行控制。主动控制下,医生通过导航系统提供最优钉道的精确位置信息,机器人根据医生的规划路径自主到达手术点;被动力拖拽控制基于导纳控制原理对医生作用在机器人末端执行器的操作力进行映射,并以此形成跟随拖动动作的机器人运动控制指令。针对力拖拽控制的实验验证了机器人在被动拖拽控制模式下能够柔顺地跟踪医生的操作动作。     

机器人辅助微创全膝关节置换手术系统

开发了面向全膝关节置换手术的机器人辅助截骨系统,实现了膝关节解剖结构精准建模、术前截骨路径3维规划、图像配准以及术中机器人可视化导航.采用多模态图像融合与主动轮廓模型分割技术实现了包含关节软骨在内的膝关节自动化建模与可视化;在此基础上采用3维交互技术实现截骨路径的术前规划;术中基于自主研发的双目视觉跟踪系统,采集关节骨表面3维点云与术前3维模型进行形状配准,完成图像空间和机器人空间之间的映射;最后通过视觉导航技术引导机器人完成截骨操作.实验结果表明,机器人系统综合定位误差为0.87 mm,截骨操作误差小于1 mm.     

联合力、声音信号的机器人钻骨操作

在近些年临床机器人辅助骨科手术中,机器人主要用来实现钉道定位,而后续钻削操作依然需要医生完成,因此本文主要针对机器人自主钻削展开研究。首先基于双层自适应模糊控制器实现皮质骨层钻削力控制操作,解决了钻削过程中的非线性时变问题,平衡了钻削进给速度和骨组织热损伤等问题。然后在机器人钻削过程中,分别基于时域和时频分析得到力特征...     

脊柱微创手术机器人速度场控制方法

在脊柱微创手术中医生徒手置钉的失误率较高,虽然机器人可以显著降低置钉的失误率,但是,手术环境的复杂性和不确定性,以及手术安全需求制约了机器人自动完成手术.本文通过建立手术空间速度场,设计速度场控制器,建立机器人运动学和动力学模型,完成机器人椎弓根螺钉自动植入的仿真和实验.相对于传统的时间轨迹控制,仿真实验验证了速度场控制方法在椎弓根螺钉自动植入过程中既能在扰动条件下保证手术轨迹的精确性又能避免对神经根的损伤.通过实验验证了速度场控制方法的可行性.     

基于正侧位投影约束的空间配准与脊柱手术导航

为提高机器人辅助脊柱手术的精确性、安全性以及易用性,将术前CT 图像与术中X 射线图像配准． 传统单平面配准法因缺乏沿光轴的深度信息而导致导航误差较大,本文通过同时计算正侧位透视图像来提高配准与 导航精度．通过分析正侧位投影空间变换模型,利用该双平面几何约束实现自动的配准初值估计并建立3 维手术空 间与CT 空间的映射．在虚拟X 射线导航基础上,利用立体视觉定位计算手术器械在CT 空间的实时位姿从而实现 3 维导航．脊柱体模实验证明该配准与导航方法的精度满足手术要求,动物椎板磨削实验表明该系统可实现实时监 控,提高手术安全性．     

基于机器学习的机器人辅助椎弓根植钉规划

为了解决脊柱手术机器人辅助实施椎弓根植钉过程中的图像辅助定位问题,该文提出了一种基于机器学习策略的椎弓根植钉规划方法。该方法利用卷积神经网络对脊柱计算机断层扫描(CT)图像进行学习和训练,通过建立神经网络模型确定网络内各层间的调整参数,然后对样本图像进行特征提 取并分类,采用交叉验证法对样本数据进行训练,验证卷积神经网络模型的正确性。通过机器学习方法对计算机断层扫描图像中适合做椎弓根植钉手术规划的图像区域进行识别,从而快速定位到植钉安全约束区域,并通过相应的图像处理方法实现植钉操作规划。医生只需要基于安全约束区域内的植钉规划完成最终的手术任务规划,能够显著提升手术效率。     

一种骨外科手术机器入的图像导航方法

精确目标定位和手术路径规划是将机器人用于长骨骨折内固定手术中的关键技术.文中使用了局部法对X光图像进行畸变校正;并提出了一种基于几何模型的对准方法,得到一条能够穿过髓内钉远端孔的路径,从而引导串联机器人锁定髓内钉.实验表明,该导航方法仅需一张X光图像,有足够的定位精度和稳定性,可大大减少手术时间,降低医生所受辐射剂量.     

基于刚软耦合模型和粒子群优化的手术机器人骨钻削力控制

脊柱椎体的多层复合结构和易热损伤特性要求手术机器人在对椎弓根进行骨钻孔时需精确控制其轴向钻削力。然而人的个体差异和脊柱-软组织构成的刚软耦合结构会使得通用型力控制器的控制精度不足,手术安全性降低。本文旨在提高轴向钻削力控制的精度。首先建立了基于质量、弹簧和Maxwell黏弹性单元的脊柱-软组织系统的刚软耦合模型。然后在离体羊脊柱上进行了应力松弛实验,并基于实测力数据对模型参数进行了标定。采用PID（比例-积分-微分）控制器来调整骨钻的轴向进给速度,并基于标定后的刚软耦合模型的传递函数,使用动态权重的标准粒子群算法整定控制器参数。最后,仿真证明闭环控制系统具有较好的动态性能和鲁棒性。离体羊脊柱骨钻孔力控制实验结果表明,轴向钻削力的阶跃力响应稳态误差小于0.15 N,相对力控制误差小于3%,且无明显超调;正弦力响应幅度在频率为3.49 rad/s时衰减到-3 d B,闭环控制系统具有较好的控制带宽。所提方法的力控制精度和控制带宽能够满足手术机器人执行骨钻削时的力跟踪要求,提高了机器人自动骨钻削过程的安全性。     

一种骨外科手术机器人的图像导航方法

精确目标定位和手术路径规划是将机器人用于长骨骨折内固定手术中的关键技术．文中使用了局部法对X光图像进行畸变校正；并提出了一种基于几何模型的对准方法，得到一条能够穿过髓内钉远端孔的路径，从而引导串联机器人锁定髓内钉．实验表明，该导航方法仅需一张X光图像，有足够的定位精度和稳定性，可大大减少手术时间，降低医生所受辐射剂量．     

基于力反馈的脊柱外科机器人系统的设计与实现

本文针对脊柱椎管狭窄症减压手术中椎管壁磨削不安全这一问题，介绍一种基于力反馈控制策略的脊柱外科机器人系统，包括监控磨削过程的检测子系统、完成磨削手术操作的运动驱动子系统和再现磨削信息状况的控制显示子系统。利用脊柱磨削手术过程中磨削力的变化特点，提出基于力反馈的脊柱外科机器人控制策略，辅助医生实现安全的脊柱手术操作。最后通过仿真实验和模拟骨实验，验证了此基于力反馈控制策略的脊柱外科机器人系统的可行性。     

Mechanical design and control of inflatable robotic arms for high positioning accuracy

In recent years, inflatable robotic arms have been developed so that physical contact with humans and working environments could be performed safety. In industry, there is a growing demand for safe industrial robots to collaborate with people and work in various environments. In general, however, the positioning accuracy of inflatable robotic arms has not been discussed. This paper proposes an inflatable link structure and a non-inflatable joint structure that could realize a high positioning accuracy for such robotic arms. This paper experimentally demonstrates that these structures can improve positioning accuracy. In addition to these structures, the joint torque characteristics of the inflatable robotic arms were investigated. In order to perform accurate motion control, a visual feedback control method was introduced for inflatable robotic arms. The mechanism and control system used in this paper can improve the positioning accuracy performance of inflatable robots. A 2-DOF inflatable robotic arm and a camera system were found to be able to achieve a high positioning accuracy (i.e. less than 1 mm).     

Design and performance evaluation of a novel robotic catheter system for vascular interventional surgery

Vascular interventional surgery (VIS) is an effective treatment method for vascular diseases. However, there are many problems in traditional VIS, such as surgeons are radiated by X-ray, the lack of well skilled surgeons, the security of the surgery will be reduced due to the Surgeons’ fatigue, high risk of the surgery. To solve these problems, a robotic catheter system is needed to protect the surgeons and enhance the safety of the surgery. In this paper, a novel robotic catheter system with master–slave structure for VIS has been developed. This system is designed with the consideration of the operation method in traditional VIS, which allows the surgeon to operate a real catheter on the master side, then the surgeon make full use of the natural catheter manipulation experience and skills obtained in conventional catheter operation. The salve manipulator operates the catheter insert into the blood vessel with following the operation of the surgeon, and the operating force of the salve manipulator is detected. On the master side, a novel damper-based magnetorheological (MR) fluid is designed to realize the force feedback, which is also used to reappear the operation force from the salve manipulator. The damper connected directly with real catheter is a piston structure using the MR fluid to realize the force feedback. It can transmit the feedback force to surgeon’s hand through the operating catheter connected with damper, which seems that the surgeon operates the catheter beside the patient. The operating transparency of the developed system has been enhanced. The mechanism of the developed system has been introduced in detail. Performance evaluation experiments for the developed robotic catheter system have been done. The experimental results indicated that the developed robotic catheter system is fit for VIS.     

Measurement error analysis and accuracy enhancement of 2D vision system for robotic drilling

Robotic drilling for aircraft structures demands higher accuracy on industrial robots than their traditional applications. Positioning error measurement and compensation based on 2D vision system is a cost-effective way to improve the positioning accuracy in robotic drilling. In this paper, we first discuss the principle of error measurement and compensation with a 2D vision system for robotic drilling and the determination of tool center point of the vision system so that the Abbe errors are eliminated in the measurement process. Measurement errors due to nonideal measurement conditions, i.e. nonperpendicularity of the camera optical axis to the workpiece surface and incorrect object distance, are mathematically modeled and experimentally verified. A method utilizing four laser displacement sensors is proposed to ensure perpendicularity of the camera optical axis to the workpiece surface and correct object distance in the measurement process, and hence to achieve high accuracy in 2D vision-based measurement. Experiments performed on a robotic drilling system show that the 2D vision system can achieve an accuracy of approximately 0.1 mm with the proposed method.     

Development of a monocular vision system for robotic drilling

Robotic drilling for aerospace structures demands a high positioning accuracy of the robot, which is usually achieved through error measurement and compensation. In this paper, we report the development of a practical monocular vision system for measurement of the relative error between the drill tool center point （TCP） and the reference hole. First, the principle of relative error measurement with the vision system is explained, followed by a detailed discussion on the hardware components, software components, and system integration. The elliptical contour extraction algorithm is presented for accurate and robust reference hole detection. System calibration is of key importance to the measurement accuracy of a vision system. A new method is proposed for the simultaneous calibration of camera internal parameters and hand-eye relationship with a dedicated calibration board. Extensive measurement experiments have been performed on a robotic drilling system. Experimental results show that the measurement accuracy of the developed vision system is higher than 0.15 mm, which meets the requirement of robotic drilling for aircraft structures.     

Design of an endoscopic solo surgery simulator for quantitative evaluation of the human–machine interface in robotic camera positioning systems

An endoscopic solo surgery simulator was designed to quantitatively evaluate the human-machine interface in robotic camera positioning systems. Our simulator can assess not only the quantitative efficiency of laparoscopic cameraworks but also the influence of cameraworks upon the accuracy of surgical actions. Two human-machine interfaces (a face motion navigation system and a voice activated system) were developed and compared. As a result, the face control interface was more efficient in cameraworks than the voice control, even under a stress to control the instruments. However, it was also found that the face motion may have an adverse influence on precise surgical actions.     

Vision-Based Path Generation Method for a Robot-Based Arc Welding System

In this paper a vision-based integrated method intended for path generation for a robot-based arc welding system, is presented. The described system is composed of the recently developed pseudo stereovision system (PSVS) or an ordinary stereovision system and the related software. A desired path can be generated, using a part or the entire edge of an image captured from a scene of the robotic environment, a line manually designed in the image, a combination of lines of the previous cases or lines belonging in successive images captured from different scenes. A user can initially process images selecting by means of pull down menus a variety of filters, edge detection methods and operations. Then the desired path as a combination of lines is selected from images. Applying our correspondence algorithm, corresponding edges can be found. Finally, a number of successive path points are calculated by means of the proposed path point calculation algorithm. In on line operation, the vision system mounted on the end-effector can capture images with the desired best view (welding view) of a scene by moving or rotating (using push buttons) the end effector of the robotic manipulator – PUMA 761. Other facilities of the described system are the selection of a variety of colors and shapes, histogram view, desired magnification, system information and automatic execution of user-selected operations. The graphical user interface is developed in Visual C++, it runs in a personal computer and communicates with the robotic manipulator (PUMA 761) through ALTER communication port.     

Enhancement and evaluation in path accuracy of industrial robot for complex surface grinding

Lower path accuracy is an obstacle to the application of industrial robots in intelligent and precision grinding complex surfaces. This paper proposes a novel path accuracy enhancement strategy and different evaluation methods for a six-degree-of-freedom industrial robot FANUC M710ic/50 used for grinding an aero-engine blade. Six groups of theoretical tool paths individually planned on this complex surface were obtained using the iso-parametric method and the constant chord height method. Then the actual paths of the robot were dynamically recorded by a laser tracker with a high frequency. A revised Levenberg-Marquardt and Differential Evolution hybrid algorithm was proposed to improve the absolute robotic positioning accuracy by considering the average curvature variation rate, the arc length and the number of cutter contact points on planning paths. The results showed that the maximum positioning error had been drastically reduced from 0.792 mm to 0.027 mm. Based on the redefinition of robotic path accuracy, including position accuracy and shape accuracy in this work, the methods MP-TLD, BP-TPD and MP-TID were proposed to evaluate the enhanced path accuracy. The evaluation results showed that the different path planning methods have almost little effect on path accuracy. Furthermore, the maximum path deviation evaluated by the MP-TLD method was reduced from 0.378 mm to 0.044 mm, evaluated by the BP-TPD method was reduced from 0.374 mm to 0.029 mm, and evaluated by the MP-TID method was reduced from 0.205 mm to 0.026 mm. It is concluded that these evaluation methods are basically valid and the average path accuracy value is about 0.035 mm, for present complex surface grinding with this typical industrial robot. Finally, the robotic grinding experiments of titanium alloy blades are conducted to further validate the effectiveness of the proposed method.     

A method for robot placement optimization based on two-dimensional manifold in joint space

This article addresses a method for placement determination of robotic drilling system on two-dimensional manifold in robot joint space. It has been proved that the feasibility of positioning error compensation on two-dimensional manifold, and that the continuity of the robot parameters in the two-dimensional space is the prerequisite to perform the compensation in previous study. It appears that there are bifurcations which might break the continuity of the robot parameters on the two-dimensional manifold due to improper placement. To avoid bifurcations, a performance index and a set of optimization procedure are proposed to achieve proper placement of robotic machining system. Experiments conducted on a KUKA robot have verified the effectiveness of the proposed placement optimization method. Experiment results indicated that positioning errors were significantly improved with the proposed method, which is beneficial for robotic machining accuracy.     

Cadaver study for spinal fusion surgery using an image-guided surgical robot system

We present a novel surgical robotic system for spinal fusion that includes a computer-based planning algorithm, O-type bi-planar fluoroscopy, and a surgical robot. The planning system determines a surgical path based on fluoroscopy images or a 3D image reconstructed using pre-operative CT data. The robot guides the surgical path that the surgeon generates with the planning system. In this cadaver study, we tested the performance of the robotic system in the treatment of eight lumbar vertebrae by comparing CT images recorded before and after surgery.