广义预测控制方法在网络遥操作机器人系统中的应用

Internet网络的时变时延及网络数据丢包严重影响了遥操作机器人系统的操作性能,甚至造成系统不稳定.为了解决这一问题,提出一种新的基于Intcrnet的遥操作机器人系统控制结构.通过在主端对给定信息加入时间标签获得过去的系统回路时延,采用多元线性回归算法,预测下一时刻系统回路时延,然后在从端设计一个广义预测控制器控制远端机器人,从而改善时变时延对系统性能的影响.应用广义预测控制器产生的冗余控制信息,降低了网络数据丢包对系统的影响.最后根据预测控制稳定性定理,推导出系统的稳定性条件.仿真试验结果表明,该方法能有效解决时变时延以及网络数据丢包引起的性能下降问题.     

基于变波阻抗控制策略的六足机器人双边遥操作

针对变时延条件下六足机器人行进任务中的跟踪性较差问题,本文提出了一种基于波阻抗在线补偿策略的六足机器人 双边遥操作控制方法。 该策略以四通道控制架构为基础,采用时延预估器对通信时延进行预估,并设计波阻抗在线调整规则, 以此提高系统的跟踪性。 同时结合时域无源性控制方法,对通信环节与环境端潜在的有源性进行二次补偿,保证系统的绝对无 源,利用 Llewellyn 准则设计主从端的控制律参数。 搭建基于 Vortex 半物理仿真实验平台与实物实验平台对本文所提出的方法 进行验证。 实验结果表明变波阻抗控制结合时域无源性控制可以保证系统的无源性,相对于传统双边遥操作速度跟踪性提高 了 84. 3% ,力波动范围降低了 84. 7% 。     

双边遥操作系统二阶滑模控制器设计

一阶滑模控制方法由于需要大的带宽和高频切换信号,以及处理系统的参数不确定和强非线性,在双边遥操作的工程应用中难以推广。针对上述问题,将二阶滑模控制和阻抗控制联合起来,设计了大时延下的控制结构,并利用全维状态观测器对主从手机械臂的加速度、速度进行了观测,实现了双边遥操作系统的鲁棒平滑控制;在此基础上,分析了加入观测器后整个系统的闭环稳定性,给出了稳定性定理,并用李雅普诺夫函数方法进行了证明;最后分两种时延情况对闭环系统进行了仿真。实验结果表明,该方法可以使系统具有了较好的稳定性能。     

大时延环境下空间机器人的可靠遥操作策略

在分析大时延环境下遥操作特点的基础上,从使用可靠性角度提出一种可靠遥操作的多层策略集。将各可靠遥操作策略分解在数据层、算法层、操作层、策略层以及系统层并分别展开说明,涵盖了大时延环境下的数据交互、空间机器人关节指令序列的嵌套位置/速度规划、操作员与遥操作系统交互、遥操作任务运行流程与应急和遥操作系统监测/在线维护等方面的策略。此外,对可靠遥操作中尚待解决的动作反演、操作引导和共享遥操作技术进行了分析和展望。开展了某不确定大时延环境下的空间机器人遥操作试验,试验的数据分析结果说明不同层次的遥操作可靠性性策略均十分必要,以操作员为对象的可靠性提升策略和设计方法是可靠遥操作技术发展的重要方向。     

基于SEM的微纳遥操作系统控制策略研究

为改善基于扫描电镜微纳遥操作系统的力觉临场感与稳定性,针对微纳遥操作系统提出一种基于滑模的阻抗控制策略。主操作手端应用阻抗控制策略,以提高主操作手的顺应性;从操作手端采用基于滑模的阻抗控制策略,解决从操作手端参数的不确定性问题。由于实现上述控制策略需要的微分控制信号难以直接获取,故在主/从控制策略中结合跟踪微分器技术进行在线获取。针对微纳遥操作系统工作于低频带,具有极大的力反馈增益(105以上)特点,利用 Liewellyn稳定判据推导出小延时下系统稳定条件。仿真和实验表明：所提出控制策略具有良好的鲁棒性,能够提供精确的力觉临场感。位置跟踪阶段最大位移误差小于0.5μm;接触阶段操作者能够精确地感知从操作手端1μN接触力。     

基于被动力反馈的遥操作电液控制系统

针对遥操作机器人现有的力反馈冲击、反馈力震荡等问题,提出了一种新型的遥操作电液控制系统。主操作端选用电液比例控制系统以实现力反馈效果,从动端选用电液伺服控制系统以实现位移跟踪效果,并建立了电液控制系统的数学模型,选用算法简单、跟踪性能较好的力反射型控制策略,对整个系统进行了Matlab/Simulink仿真,结果表明,新型遥操作电液控制系统具有较好的位移跟踪及力反馈效果。     

挖掘机器人遥操作的实现

针对现有半自主遥控挖掘机器人存在的不足,提出一种基于动作的挖掘机器人遥操作控制方案。首先在综合论述该遥操作系统控制原理基础上,重点阐述了挖掘机各工作装置遥操作的实现,并搭建基于动作的挖掘机器人遥操作实验平台进行实验验证。结果表明:该遥操作系统不仅设备简单轻便,操作灵活,而且主-从端跟随性能良好,能达到挖掘机遥操作作业的基本要求,为挖掘机器人遥操作系统的开发与设计提供参考。     

光学运动捕捉在机械臂遥操作控制中的应用研究

针对传统机械臂的遥操作控制直观性不强、操作繁琐等问题，本文提出了一种基于光学运动捕捉的机械臂遥操作控制方法。建立了运动捕捉系统与机械臂的标定模型，实现了坐标系之间的转换；在ROS-kinetic中建立服务器和客户端，实现了不同系统数据之间相互转化与实时传输。通过在引导机械臂末端粘贴标记点、构建刚体的方式进行跟踪试验，结果表明该方法降低了主端的复杂程度，在保证从端操作精度的情况下，可实时地完成六自由度机械臂遥操作任务，方法操作简单、可移植性和可扩展性强。     

力-位置型力觉临场感机器人变增益控制及其稳定性研究

对于力觉临场感机器人系统,在保证系统稳定性的基础上,提高操作透明性是其完成精细任务的关键。本文通过对力-位置型力觉临场感遥操作场机器人系统控制结构的分析,提出了一种变增益力-位置型控制结构,通过改变从端的位置控制增益,提高了遥操作系统的可操作性。同时通过建立系统的动力学方程,利用李亚普诺夫函数分析了系统在约束运动下的稳定性。实验结果表明,这种控制结构在保证系统稳定的基础上实现了良好的控制透明性。     

基于虚拟环境的遥操作机器人主从交互系统设计

针对遥操作机器人系统中的时延问题,设计了一种基于虚拟环境的机器人遥操作主从交互系统.利用Java/Java3D进行分布式虚拟环境以及虚拟机器人的三维建模;通过JNI方法建立主手设备与虚拟环境的交互接口.操作者通过操纵主手而对虚拟机器人进行关节驱动,提高了主从控制的实时性.     

Real-time mobile robot teleoperation via Internet based on predictive control

A remote control system that can control a mobile robot in real time via the internet is proposed. To compensate for the network delay and counteract its impact on the teleoperation system, a predictive control scheme based on the modified Smith predictor proposed is selected. To ensure the stability and transparency of the system, a dynamic model manager is designed based on the information exchange between the sensors at the master and slave sides. To precisely predict the time delay, a new timer synchronization algorithm is proposed. To decrease delay- jitter, a new data buffer scheme is performed. Force feedback and a virtual predictive display are introduced to enhance the real-time efficiency of teleoperation. The usefulness and effectiveness of the proposed method and system are proven by teleoperation experiments via the internet over a long distance.     

Design of feedforward and feedback position control for passive bilateral teleoperation with delays

Bilateral teleoperation systems connected to computer networks such as the internet must be able to operate with varying time delays since such systems can easily become unstable. A passivity concept has been used as the framework to solve the stability problem in the bilateral control of teleoperation systems. Passivity and tracking performance are recovered using a control architecture that incorporates time varying gains into the transmission path, feedforward, and feedback position control. The proposed architecture has an inner component that can accommodate any configuration but still remain stable and passive even with varying time delay. The simulation results for a single degree of freedom master/slave system demonstrate the performance of the proposed control architecture.     

基于虚拟现实的机器人遥操作关键技术研究

机器人遥操作是实现空间、医疗及深海等领域作业的重要手段,基于虚拟现实的机器人遥操作是克服时延的有效方法,具有透明性强、稳定性高的优点,成为当前机器人遥操作的主要方式。首先分析了基于虚拟现实的机器人遥操作系统的关键组成部分,并对其关键模块的具体作用进行了介绍;其次,归纳分析了各类虚拟现实环境建模方法,主要从几何建模和动力学建模方面展开,阐述了每种方法的应用领域、主要特点;此外,进一步分析了遥操作虚拟夹具设计的构建方法及适用领域。最后对当前存在的难点进行总结,指出今后研究的思路。     

Real-time mobile robot teleoperation via Internet based on predictive control

A remote control system that can control a mobile robot in real time via the internet is proposed. To compensate for the network delay and counteract its impact on the teleoperation system, a predictive control scheme based on the modified Smith predictor proposed is selected. To ensure the stability and transparency of the system, a dynamic model manager is designed based on the information exchange between the sensors at the master and slave sides. To precisely predict the time delay, a new timer synchronization algorithm is proposed. To decrease delay-jitter, a new data buffer scheme is performed. Force feedback and a virtual predictive display are introduced to enhance the real-time efficiency of teleoperation. The usefulness and effectiveness of the proposed method and system are proven by teleoperation experiments via the internet over a long distance. __________ Translated from Robot, 2007, 29(4): 305–312 [译自: 机器人]     

Dual-user nonlinear teleoperation subjected to varying time delay and bounded inputs

A novel trilateral control architecture for Dual-master/Single-slave teleoperation system with taking account of saturation in actuators, nonlinear dynamics for telemanipulators and bounded varying time delay which affects the transmitted signals in the communication channels, is proposed in this paper. In this research, we will address the stability and desired position coordination problem of trilateral teleoperation system by extension of (nP+D) controller that is used for Single-master/Single-slave teleoperation system. Our proposed controller is weighted summation of nonlinear Proportional plus Damping (nP+D) controller that incorporate gravity compensation and the weights are specified by the dominance factor, which determines the supremacy of each user over the slave robot and over the other user. The asymptotic stability of closed loop dynamics is studied using Lyapunov-Krasovskii functional under conditions on the controller parameters, the actuator saturation characteristics and the maximum values of varying time delays. It is shown that these controllers satisfy the desired position coordination problem in free motion condition. To show the effectiveness of the proposed method, a number of simulations have been conducted on a varying time delay Dual-master/Single-slave teleoperation system using 3-DOF planar robots for each telemanipulator subjected to actuator saturation.     

Design and stability analysis of impedance controller for bilateral teleoperation under a time delay

A new impedance controller is proposed for bilateral teleoperation under a time delay. The proposed controller does not need to measure or estimate the time delay in the communication channel using the force loop-back. In designing a stable impedance controller, absolute stability is used as a stability analysis tool, which results in a less conservative controller than the passivity concept. Moreover, in order to remove the conservatism associated with the assumption of infinite port impedances, the boundaries of human and environment impedance are set to finite values. Based on this, this paper proposes a parameter design procedure for stable impedance controllers. The validity of the proposed control scheme is demonstrated by experiments with a 1-dof master/slave system.     

基于力估计与切换控制的六足机器人三边遥操作

传统三边遥操作系统的力传感器对主从端交互力进行测量时局限性较大,且在共享权重切换时易导致系统不稳定,本 文设计基于力估计与权重切换控制的六足机器人三边遥操作控制架构。 针对系统各端口交互力信息缺失的问题,设计一种非 线性交互力估计器,实现对各端口间交互力的实时估计。 聚焦双操作者控制权重动态调整过整中的柔顺切换问题,本文基于共 享控制策略,设计权重因子自适应切换算法。 为保证所提出系统的稳定性及透明度,融合力估计器及权重切换算法,设计遥操 作系统的控制器。 通过力反馈设备分别和 Vortex 与 ElSpider 六足机器人搭建半物理仿真平台与实物实验平台,对本文提出控 制方法进行验证。 相对于传统三边遥操作,实验表明在平坦地形下速度跟踪性提高了 45. 12% ,力跟踪提高了 64. 71% ;在崎岖 地形下速度跟踪提高了 39. 02% ,力跟踪提高了 29. 41% 。     

Modified Smith predictor design for periodic disturbance rejection

In this paper, a modified Smith predictor control scheme is proposed for periodic disturbance rejection in both stable and unstable processes with time delay. Without affecting the superior setpoint response of Smith predictor control, the regulation performance under periodic disturbance can be enhanced significantly by the proposed design. Meanwhile, the asymptotical rejection for non-periodic disturbance will also be improved. Internal stability is investigated for a closed-loop control system. The effectiveness of the proposed scheme will be demonstrated by simulations as well as a test on an experimental thermal system.