【作者】 武博；

【导师】 蔡萍；

【作者基本信息】 上海交通大学 ， 仪器科学与技术， 2013， 博士

【摘要】 对腔镜虚拟手术力觉交互系统的关键技术进行研究，旨在更有效的训练医生的手感，提高手术成功率。力觉交互系统通过力觉交互装置模拟真实的腔镜手术操作，通过软组织的力学模型计算得到交互力，给医生以逼真的触觉和力觉感知。力觉交互装置是一套有多个自由度的运动机构，由多个构件组成。在操作杆的整个运动空间里，重心不可能始终落在支承面上。操作者对力觉交互装置进行操作时，操作杆重心的移动必然会使部分的重力作用在操作者手上，影响操作者的手感，使操作者的沉浸感变差，因此对装置进行重力补偿非常重要。论文通过旋量理论对五自由度力觉交互装置进行了运动空间分析和静力学分析，并基于此计算力觉交互装置操作杆的重力矢量在运动空间中各自由度上的分力，通过驱动电机输出相应的补偿力来对消装置的重力，通过ADAMS仿真软件通过比较重力补偿前后的位移误差验证了所计算补偿力的正确性。力觉交互系统的通信延时会使控制器不能及时引起控制变量变化，控制不及时会导致超调量增大，人体器官各部分的异质性导致的虚拟环境模型参数的差异性和力觉交互装置装配的差异性同样会影响系统的性能。论文对包含力觉交互装置动力学模型、电机电气模型及虚拟环境模型在内的力觉交互系统性能进行了分析，使用内模控制来改善系统的鲁棒性，并消除系统时滞的影响。在内模控制的基础上设计自适应律，通过实时修正参考模型来逼近实际控制对象模型，结果证明该控制方法相比于PID控制不但可以降低超调量到4.55%，还可以将调节时间控制于0.02s以内，有效的改善了系统性能。为了抑制维间耦合，论文设计了滑移结构六维力传感器，该传感器具有小尺寸、低量程和高分辨力的特点，传感器的整体尺寸为52mm328mm，量程为20N，分辨力为20mN，测力精度为1%F.S.。论文通过理论分析和ABAQUS有限元软件分析了传感器解耦特性，结果表明传感器相比于浮动梁传感器，解耦更加彻底，最大维间耦合误差为0.34%，远小于浮动梁结构的解耦误差1.14%。分析了滑移间隙和滑槽不对称性对解耦的影响，给出能达到解耦要求所需要的加工公差等级须达到国标GB/T1800.3-1998。设计了标定装置对传感器进行标定，得到静态标定矩阵及标定时各维力或力矩的维间耦合误差和灵敏度。设计了可实现穿刺、切割、夹持和缝合操作的五自由度力觉信息采集装置，对具有粘弹性特性的软组织在手术操作时变形、破裂和破裂延伸三种形式状态的相互转换进行分析，分析交互过程中变形力、摩擦力和破裂延伸力的力学特性。对离体软组织与手术器械多自由度的交互力觉信息进行采集，建立了猪心软组织与手术器械在穿刺、切割、缝合和夹持过程中的指数力学模型和多项式力学模型，所使用的力学模型中的参数反映了软组织的粘弹性特性，其中多项式形式的力学模型可以方便通过计算机实现。更多还原

【Abstract】 In view of the laparoscopic surgeon training, the key technology of the virtual surgeryhaptic interaction system is researched to improve surgeons‘operation feeling. The hapticinteraction system can provide the realistic haptic perception with the simulation operationusing haptic interaction device and the force model of soft tissue.The haptic interaction device is composed of many parts and can move in multiple DOF.The gravity center of the operation lever will not be located on the support point in themovement space all the time. When surgeons operate the haptic interaction device, the gravityforce will worsen the surgeons feel with the gravity center movement. So the gravitycompensation is required. The screw theory is used to make the spatial analysis and the staticanalysis, and based on the analysis the component force is calculated for the motors‘compensation torque. The ADAMS is used to verify the correction of the calculatedcompensation force through the displacement error comparison before and after gravitycompensation.Haptic interaction system delay makes the controller cannot response timely to thevariable changes and the system is difficult to adapt to the changes of the virtual environmentmodel parameters. The haptic interaction system model including haptic interaction devicedynamics model, the motor electrical model and virtual environment model is analyzed. Theinternal model control is used to improve the robustness of the system and eliminate thesystem delay and the adaptive internal model control is used to real-time correct the systemmodel parameters. Finally, the results of the simulation and experiment indicate that thecontrol strategy can not only reduce the overshoot value to4.55%but also less the controltime to0.02s, and the system performance is improved.To measure the tool-tissue interaction force, the sliding structure six-axis force/toque sensor is developed and the sensor features small size, low range and high resolution. Theoverall size is52mm328mm, the measurement range is20N, the resolution of the sensor is20mN and the measurement accuracy is1%F.S.. Both the theoretical analysis and finiteelement analysis are used to indicate that the sensor can decouple more thoroughly thefloating beams structure sensor. The maximum coupling error can be decreased to0.34%,which is less than1.14%of floating beams structure sensor. Considering the machining error,the influence of the sliding clearance and the asymmetric grooves on decoupling is analyzedand the required machining tolerance level GB/T1800.3-1998is given. Finally, the sensorcalibration device is designed to make the sensor calibration and the static calibration matrix,the coupling error and the sensitivity is obtained.The five degrees of freedom haptic information acquisition device is designed to get theinteraction information acquisition between the isolated soft tissue and the surgical toolsduring the puncture, cutting, clamping and suturing operation. The conversion state of thedeformation, cracking and fracture is analyzed and the deformation force, friction force andrupture force during the force interaction is analyzed. The exponential and polynomial forcemodel of the soft tissue during the puncture, cutting, clamping and suturing operation isestablished based on the haptic information acquisition experiments. The force model canillustrate the viscoelastic properties of soft tissue and the polynomial force model can beeasily realized by the computer.更多还原