腹腔微创手术机器人的主从控制

为提高基于内窥镜的腹腔微创手术机器人系统的手眼协调一致性,提出了一种主从控制方法.基于旋量理论建立从手系统的正逆运动学模型,基于运动模型提出内窥镜坐标系下的主从运动控制算法,该算法包含了运动的一致性控制、相对运动控制和比例运动控制.主手的腕部为被动方式(无电机驱动),不能在任意位置保持静止,在手术开始、中途中断或调节主手工作空间时,主手和从手姿态不能保持一致.为此,开展3种辅助功能实现研究,分别为主从姿态配准、手术器械更换和主从二次映射.最后进行了套环和穿线实验,这两组实验最大空间位置误差均小于1 mm,说明该算法可有效地提高手眼协调的一致性.     

主从同构穿刺手术机器人遥操作控制策略研究

文章在分析了穿刺机器人系统功能需求的基础上,搭建了主从遥操作系统的半实物仿真平台。基于等效微分变换的思想,提出雅克比矩阵(Jacobian Matrix)方法和比例微分(Proportional-Derivative,PD)控制律的联合控制方法。通过设计数字滤波器来消除外科医生的手部低频抖动对穿刺手术机器人精度的影响。实验结果表明从机器人末端执行器在笛卡尔空间坐标下能够精确快速安全地跟随主机器人末端执行器的位置变化,并且主机器人端的手部抖动能够被消除。     

导管机器人系统的主从介入

传统的血管微创介入手术过程中医生在手术现场,其不可避免地遭受大量的X射线照射;并且导管的操作难度较大,对医生插管技术要求过高.针对此问题,研制了一种新型的集成有双电磁传感器的可定位导管机器人,并采用D-H法对其进行了运动学分析,同时设计了一套介入装置来代替医生进行导管操作,并通过对主从控制方法的研究实现了该系统的主从介入.在介入过程中,医生通过主手控制介入装置动作来实现导管的推/拉、旋转和弯曲操作,并可在引导图像的辅助下完成插管手术操作.实验表明,开发的可控导管具有较好的操作性能,介入装置实现了3种基本的介入操作,提高了导管的定位精度,同时主从介入方式也保证了医生在手术过程的安全性.     

微创血管介入手术机器人的主从交互控制方法与实现

微创血管介入手术是治疗冠心病的重要治疗手段, 手术中要求对导管、导丝等介入器械高精度递送.得益于机器人技术的高精度、可远程操作等特点, 血管介入手术机器人的研制受到了极大关注.在微创血管介入手术中, 按导管或导丝远端所处血管部位, 将介入器械递送过程分为三个阶段: 1) 主动脉阶段:导丝或导管远端位于主动脉, 需快速前送, 以减少X射线和造影剂的使用; 2) 冠脉入口阶段:导丝或导管远端进入冠脉, 此时需选择相应的病变冠脉分支; 3) 冠脉病变阶段:导丝或导管远端位于狭窄病变部位, 需要高精度操作才能使导丝或导管穿过狭窄病变.针对器械递送的不同阶段, 提出具有运动缩放的主从控制方法, 通过改变血管介入手术机器人主端和从端之间的运动缩放关系, 实现机器人从端对主端操作的放大、缩小或等比例复现.通过在微创血管介入手术机器人平台实验, 验证了机器人从端对主端操作缩放的可行性和有效性.通过操作时间和操作精度对比分析得到:在缩放因子为4时操作时间减少39.9%;在缩放因子为1/4时, 平移和旋转操作精度分别提高72.9%和77.1%.     

一套主从操作的双臂手术机器人系统

本文展示了一套经自然腔道手术(NOTES:Natural Orifice Transluminal Endoscopic Surgery)的手术系统的开发。本系统主要包括一对遥操作主手,以及具有多个自由度的连续体结构的夹钳及黏膜切开刀。着重阐述了一对主手、末端连续体夹钳及连续体黏膜切开刀的机械结构,展示了主手和末端夹钳、切开刀之间的主从控制,运动学算法的验证以及在双通道内镜下夹取切割效果的实验验证,进而探究整套手术系统后续应用的可行性。     

具有震颤抑制的微创机器人主从控制系统设计

详述了一种用于抑制微创手术机器人震颤现象的主从控制系统，提出了针对人手生理震颤的新型零相位滤波方法及针对从操作臂关节“粘滑行为”的前馈补偿PD伺服算法。新型零相位滤波避免了传统低通滤波器容易造成延时和传统零相位滤波无法在线使用的缺点，前馈补偿PD伺服算法通过摩擦补偿克服了非线性摩擦对从操作臂运动造成的影响。最后，对系统进行仿真及实验，结果表明该方法能有效地抑制机器人手术工具末端的震颤现象。     

空间机器人的主从和自主控制

本文在回顾空间机器人控制系统结构标准(NASREM)的基础上,根据空间机器人未来的应用前景,讨论了遥控主从和监控自主两神控制方式的实现以及必须解决的问题。     

一种主从操作的连续体机器人

本文展示了一个主从操作的连续体机器人(CR:Continuum Robot)系统的开发。此系统主要包括主手部分和CR从手部分。主手是具有六个自由度的串联式结构;从手的CR具有五个自由度,包括三个空间位置自由度、一个旋转自由度和一个夹钳开合自由度。着重阐述了主手的设计、从手端CR模块的设计和CR运动学算法的开发,并进行了主从控制的初期实验验证。通过这些功能的实现,该主从操作的柔性机器人将来可以成为经自然腔道手术(NOTES:Natural Orifice Transluminal EndoscopicSurgery)的重要工具。     

七自由度数据臂实现主从控制研究与仿真实验

介绍了一种BUAA-Ⅲ型七自由度数据臂对异构从动机器人的主从控制方法;针对数据臂主从控制多为异构控制这一特点,提出了将关节控制与位置控制结合面向任务的控制方案,通过编程实现了对PUMA262型六自由度虚拟机器人的仿真控制,并应用BUAA-Ⅲ型数据臂控制虚拟机器人完成了抓棒仿真实验;从而,验证了针对BUAA-Ⅲ型数据臂的异构主从控制方案的可行性和可靠性.     

Design and control of JAIST active robotic walker

This paper presents the design and control of a novel assistive robotic walker that we call “JAIST active robotic walker (JARoW)”. JARoW is developed to provide potential users with sufficient ambulatory capability in an efficient, cost-effective way. Specifically, our focus is placed on how to allow easier maneuverability by creating a natural interface between the user and JARoW. For the purpose, we develop a rotating infrared sensor to detect the user’s lower limb movement. The implementation details of the JARoW control algorithms based on the sensor measurements are explained, and the effectiveness of the proposed algorithms is verified through experiments. Our results confirmed that JARoW can autonomously adjust its motion direction and velocity according to the user’s walking behavior without requiring any additional user effort.     

受限的非仿射非线性系统的自适应控制

针对受限的非仿射非线性系统,结合自抗扰思想提出了非仿射系统的扩张状态观测器(ESO)设计,从而将辅助系统设计技巧拓展到了非仿射系统,然后利用反演和指令滤波器设计了自适应控制器,为受限的不确定非仿射系统提供了新的设计思路.为了补偿受限带来的影响,引入了辅助系统,它的状态被用来补偿跟踪误差.指令滤波器用来处理虚拟控制受限问题,同时获得虚拟控制导数的估计,避免了backstepping中对它的繁琐计算,扩张状态观测器被用来估计系统的未知非仿射非线性项和外部干扰.利用输入状态稳定性(ISS)分析了闭环系统的全局一致有界稳定性.最后仿真结果验证了该设计方案的有效性.     

Boundary feedback stabilisation of a flexible robotic manipulator with constraint

In this paper, the flexible robotic manipulator is modelled as a distributed parameter system, represented by a group of partial differential equations and ordinary differential equations. Control is designed at the boundary of the robotic manipulator based on integral-barrier Lyapunov function to suppress the vibration of the elastic deflection and track the desired angular position. With the proposed boundary control, the manipulator can be driven to the desired set-point with angular position and elastic deflection stay under the former setting constraint. Uniformed boundedness of the closed-loop system under the unknown time-varying disturbance is achieved. Stability analysis of the closed-loop system is given by employing the Lyapunov stability theory. Simulation results illustrate the effectiveness of the proposed boundary controller for ensuring output constraint and suppressing vibrations.     

PD with sliding mode control for trajectory tracking of robotic system

Good tracking performance is very important for trajectory tracking control of robotic systems. In this paper, a new model-free control law, called PD with sliding mode control law or PD–SMC in short, is proposed for trajectory tracking control of multi-degree-of-freedom linear translational robotic systems. The new control law takes the advantages of the simplicity and easy design of PD control and the robustness of SMC to model uncertainty and parameter fluctuation, and avoid the requirements for known knowledge of the system dynamics associated with SMC. The proposed control has the features of linear control provided by PD control and nonlinear control contributed by SMC. In the proposed PD–SMC, PD control is used to stabilize the controlled system, while SMC is used to compensate the disturbance and uncertainty and reduce tracking errors dramatically. The stability analysis is conducted for the proposed PD–SMC law, and some guidelines for the selection of control parameters for PD–SMC are provided. Simulation results prove the effectiveness and robustness of the proposed PD–SMC. It is also shown that PD–SMC can achieve very good tracking performances compared to PD control under the uncertainties and varying load conditions.     

Design and control of a three-fingered tendon-driven robotic hand with active and passive tendons

This paper presents a design of a three-fingered robotic hand driven by active and passive tendons and proposes control methods for this hand. The tendon-driven robotic hand consists of the thumb, the index and the middle fingers. The robotic thumb can move all the joints independently. In contrast, the index and the middle robotic fingers are under-actuated using the combination of active and passive tendons, and move the terminal two joints synchronously, which is one of the important features of the human digits. We present passivity-based impedance and force controllers for tendon-driven robotic fingers and discuss how to combine them for fast and secure grasps. We experimentally validate that the robotic hand moves fast and manipulates an object and demonstrate that the robotic hand grasps objects in diverse ways.     

Master-slave intelligent robot telepresence system

In this paper, the analysis and design of master-slave intelligent robot telepresence system are discussed. When the operator acts on the master manipulator, the position and attitude information of the master manipulator are gathered by the computer. After calculating and coordinate transforming, the data are send to the computer of the slave manipulator. Then the slave manipulator-PUMA562 robot follows the master manipulator's movement precisely. Six-dimension force/toque sensor(lord cell) is mounted on the slave manipulator. As the master manipulator and the toque on the slave manipulator are different in structure, the force and the slave manipulator should be send to the master manipulator computer and dissociated by the master manipulator computer. Proper ratio of the force on the master manipulator and the force on the slave manipulator is selected, and distribute to the master manipulator joints. So that the operator could feel the force from the master manipulator, which is obtained by the motors of the joints. The proposed control scheme is introduced to a prototype master-slave system and the experimental results show the validity of the proposed scheme.     

A shape adaptive motion control system with application to robotic polishing

This paper presents a new shape adaptive motion control system that integrates part measurement with motion control. The proposed system consists of four blocks: surface measurement; surface reconstruction; tool trajectory planning; and axis motion control. The key technology used in surface measurement and surface reconstruction is the spatial spectral analysis. In the surface measurement block, a new spectral spectrum comparison method is proposed to determine an optimal digitizing frequency. In the surface reconstruction block, different interpolation methods are compared in the spatial spectral domain. A spatial spectral B-spline method is presented. In the tool trajectory planning block, a method is developed to select a motion profile first and then determine tool locations according to the reconstructed surface in order to improve the accuracy of the planned toolpath. Based on the proposed methods, a software package is developed and implemented on the polishing robot constructed at Ryerson University. The effectiveness of the proposed system has been demonstrated by the experiment on edge polishing. In this experiment, the shape of the part edges is measured first, and then constructed as a wire-frame CAD model, based on which the tool trajectory is planned to control the tool to polish the edges.     

Boundary control for a flexible string system with input saturation constraint

In this study, we focus on the boundary control problem for a vibrating string system with saturated input under the condition of external disturbances. Based on the backstepping approach, a boundary vibration control scheme is proposed to globally stabilize the string around the equilibrium position. A smooth hyperbolic tangent function is exploited to restrict the control input, an auxiliary system and a Nussbaum function are adopted to cope with the nonlinear term derived from the input saturation, and a disturbance observer is employed to tackle the boundary disturbance. The developed controller can assure the convergence of the closed‐loop system state to a small neighbourhood of zero. By the appropriate choice of control design parameters, numerical simulation is conducted to show the effectiveness of the derived control.