基于波变量的时延双边遥操作系统设计

针对波变量法在任意时延下能保证时延双边遥操作系统的稳定,但却降低主从端之间跟踪性的问题,提出一种改进基于波变量遥操作系统的设计方案;该方案引入PD控制器调整主从端速度误差,并采用PI控制器控制从端;最后,对调整和未调整的基于波变量双边遥操作系统分别进行仿真实验;实验结果表明,与未调整的系统相比,调整的系统在一定程度上极大地降低了主从端位置、速度和力的跟踪误差,使得该方案在保证系统稳定的前提下有效提高了系统透明性。     

空间遥操作机器人主从双边自适应内模控制

天地大时延严重破坏具有力反馈的空间遥操作机器人系统的稳定性和透明性;针对天地大时延和未知的从手操作环境,基于内模控制和自适应控制思想设计一种自适应内模控制器;推导从手环境参数辨识模型,基于带遗忘因子的递推最小二乘滤波辨识环境模型,并利用辨识信息构建自适应内模控制器;基于单参数SNPIDC算法分别设计主手和从手自适应控制器;大量的仿真结果证明,在设计的主从双边自适应内模控制器作用下,空间遥操作机器人系统稳定性好,对未知环境适应能力强,系统透明性好,阻抗匹配程度高,且操作人员临场感强。     

无源散射变换的双边移动机器人网络遥操作

网络遥操作系统的随机时延给控制器设计带来巨大挑战,严重时破坏系统的稳定性。首先对遥操作无源理论及其波变量控制方法做了简单综述,然后提出直接无源散射变换方法,它将无源双边控制方法推广到具有随机时延的网络遥操作系统中去,保证网络遥操作系统在任何不对称随机网络时延情况下稳定。最后基于此变换方法设计了一个虚拟主从手双边移动机器人网络遥操作方案,并进行了仿真验证,结果表明结出的设计方法能满足系统性能要求。     

空间机器人遥操作控制系统研究

本文针对空间机器人工作环境特殊性要求,基于无源性理论提出了一种适用于变时延的力反馈双边控制系统,利用PD+d控制器有效补偿了由操作者和从端环境带来的干扰。运用李雅普诺夫函数对系统的稳定性能进行分析,并利用仿真实验验证了系统的透明性和跟踪性。此外,本文所提出的稳定性判别方法,经改进后也可应用于其他控制方案的稳定性分析。     

基于时域无源性控制的六足机器人双边触觉遥操作

随着六足机器人研究工作的深入,针对其遥操作系统的开发面临诸多挑战.为了弥补松软接触条件对系统可控性及稳定性的影响,提出一种基于时域无源性控制(time-domain passivity control,TDPC)的六足机器人双边触觉遥操作方法.其主从两端采取位置-速度的交互模式,通过分析足-地柔性接触的作用机理,构建无源观测器和无源控制律以补偿足底滑移所导致环境系统的潜在有源性,采用速度跟踪模式设计基于触觉力反馈的系统控制架构,并利用Llewellyn准则确定控制律参数的稳定范围.最后,搭建半物理仿真实验平台并验证所提出的双边触觉遥操作方法在松软地形条件下能够保证六足机器人遥操作系统的稳定,且兼具较好的持续跟踪能力.     

基于波变量补偿的阻抗匹配时延双边遥操作

通信时延是遥操作系统中固有的问题,它会严重影响遥操作的性能,降低系统的稳定性和跟踪性。基于无源理论的波变量法可以保证遥操作系统在任意时延下稳定,是解决时延问题的一个重要方法。然而,波变量法带来的波反射会阻扰有用信号的传输,降低了主从端信号的跟踪性,严重时甚至会导致整个系统振荡。针对这一问题,提出了一种基于波变量补偿的阻抗匹配双边遥操作系统结构,旨在减少波反射,提高操作者的临场感和系统的跟踪性。通过仿真实验,结果表明所提方法能够保证固定时延条件下遥操作系统的稳定性,并具有较好的跟踪性。     

基于多传感器的机器人遥操作人机交互系统

为了增强机器人人机交互系统的自然性,提出了基于多种传感器的非接触式人机交互系统设计方案,系统通过检测操作者手部动作和手部位置姿态的变化实现机器人的遥操作。研制了肌电传感器,获取手臂上一对拮抗肌上的表面肌电信号,并以此来判断机器人操作者的部分手部动作;利用Kinect体感设备和惯性测量单元获取手臂三维位置和姿态角信息。通过网络将人手的动作及位置姿态发送至机器人控制系统,以完成对机器人的控制。系统综合多种传感器的优点,极大减小了传统接触式交互方式对操作者运动范围的限制,实现了自然交互,实验表明了其有效性。     

基于虚拟环境的多操作者多机器人协作遥操作系统

建立了基于虚拟环境的多操作者多机器人协作遥操作系统,采用3层C/S结构的控制系统软件构架.根据实验系统平台工作场景对分布式虚拟环境进行建模,以实现多操作者对多机器人的分布式控制.结合多操作者多机器人遥操作系统的结构特点,采用本地滞后原理对分布式虚拟环境的一致性控制进行了研究,解决了遥操作系统一致性控制中时钟同步、滞后时...     

基于操作者表现的机器人遥操作方法

针对遥操作机器人,提出了一种操作者表现（PoT）的在线识别方法以及基于PoT的遥操作移动机器人控制框架.首先,通过分析遥操作者的EEG（脑电信号）获得5个PoT指标,并使用BP（反向传播）神经网络对其进行建模,从而实现对遥操作者表现的在线识别.随后,设计了一种基于PoT动态调节遥操作共享控制系统中的控制权重的策略.选取3名不同遥操作者进行了在线PoT识别及基于PoT的共享控制遥操作实验,实验结果证明该方法能够有效地在线识别PoT,同时基于PoT的控制框架提升了遥操作的效率和安全性.     

遥操作旋转运动梁系统多目标优化控制研究

本文以旋转运动柔性梁为对象,采用基于胞映射的多目标优化方法进行遥操作系统双边控制研究.首先建立遥操作旋转运动柔性梁系统动力学方程,其次考虑信号传输时滞和系统主从端跟踪误差信号设计主端控制器和从端控制器,并利用Lyapunov稳定性理论获得保证闭环控制系统稳定的控制增益所需要满足的条件.由于满足稳定性条件并不意味着好的控制性能,最后利用基于胞映射的多目标优化方法进行优化控制设计,得到同时满足多个不同目标的控制增益的Pareto最优解集.仿真结果表明所获得的控制增益能够有效实现遥操作系统主从端的信号跟踪,并且操作者能够及时感受到从端环境的变化.     

Stable Delayed Bilateral Teleoperation of Mobile Manipulators

This paper proposes a control scheme for a stable teleoperation of non‐holonomic mobile manipulator robots. This configuration presents high‐coupled dynamics and motion redundancy. The problem approached in this work is the teleoperation of the end effector velocity of the Mobile Manipulator, while system redundancy is used to achieve secondary control objectives. We considered variable asymmetric time delays as well as non‐passive models of operator and environment. From this study, it is possible to infer the control parameters, depending on the time delay, in order to assure stability. Finally, the performance of the delayed teleoperation system is evaluated through simulations of human‐in‐the‐loop internet teleoperation.     

Bilateral Teleoperation of Multiple Agents with Formation Control

This paper studies the formation problem for multislave teleoperation system over general communication networks, where multiple mobile slave agents are coupled with a single master robot. The forward and backward network transmission time delays are assumed to be asymmetric and time-varying. Due to the quantization in the network, a dynamic quantization strategy is provided to quantize the output signals of the master robot and slave agents before transmitting. Then, a novel masterslave protocol is designed to achieve the formation task under variable time delays and quantization. Additionally, the sufficient conditions for stability are presented to show that the formation protocol can stabilize the master-slave system under variable time delays and quantization. Finally, simulation are performed to show effectiveness of the main results.      

Transparency and Stability of Bilateral Kinesthetic Teleoperation with Time-Delayed Communication

This paper presents a novel control approach that simultaneously ensures stability and transparency of bilateral kinesthetic teleoperation in case of communication delay. The approach rests upon a straight-forward combination of two-port lossless line theory, proper adaptation of line terminating impedance functions and situation dependent switching of adaptation filters. Application of a resulting transparency oriented control strategy to 1- or multi-DoF telemanipultion systems leads to improvements in human operator's presence feeling and task performance.     

Composite Nonlinear Bilateral Control for Teleoperation Systems With External Disturbances

This paper presents a new composite nonlinear bilateral control method based on the nonlinear disturbance observer (NDOB) for teleoperation systems with external disturbances. By introducing the estimations of NDOB and systems' nominal nonlinear dynamics into controller design, a NDOB based composite nonlinear bilateral controller is constructed to attenuate the influence of disturbance and uncertain nonlinearities. As compared with the existing bilateral control methods which usually achieve force haptic (i.e., contact force tracking) through a passive way, the newly proposed method has two major merits: 1) asymptotical convergence of both position and force tracking errors is guaranteed; 2) disturbance influence on force tracking error dynamics is rejected through the direct feedforward compensation of disturbance estimation. Simulations on a nonlinear teleoperation system are carried out and the results validate the effectiveness of the proposed controller.      

A Composite State Convergence Scheme for Bilateral Teleoperation Systems

State convergence is a novel control algorithm for bilateral teleoperation of robotic systems. First, it models the teleoperation system on state space and considers all the possible interactions between the master and slave systems. Second, it presents an elegant design procedure which requires a set of equations to be solved in order to compute the control gains of the bilateral loop. These design conditions are obtained by turning the master-slave error into an autonomous system and imposing the desired dynamic behavior of the teleoperation system. Resultantly, the convergence of master and slave states is achieved in a well-defined manner. The present study aims at achieving a similar convergence behavior offered by state convergence controller while reducing the number of variables sent across the communication channel. The proposal suggests transmitting composite master and slave variables instead of full master and slave states while keeping the operator’s force channel intact. We show that, with these composite and force variables; it is indeed possible to achieve the convergence of states in a desired way by strictly following the method of state convergence. The proposal leads to a reduced complexity state convergence algorithm which is termed as composite state convergence controller. In order to validate the proposed scheme in the absence and presence of communication time delays, MATLAB simulations and semi-real time experiments are performed on a single degree-of-freedom teleoperation system.      

Position Measurement Based Slave Torque Feedback Control for Teleoperation Systems With Time-Varying Communication Delays

Bilateral teleoperation system is referred to as a promising technology to extend human actions and intelligence to manipulating objects remotely. For the tracking control of teleoperation systems, velocity measurements are necessary to provide feedback information. However, due to hardware technology and cost constraints, the velocity measurements are not always available. In addition, the time-varying communication delay makes it challenging to achieve tracking task. This paper provides a solution to the issue of real-time tracking for teleoperation systems, subjected to unavailable velocity signals and time-varying communication delays. In order to estimate the velocity information, immersion and invariance (I&I) technique is employed to develop an exponential stability velocity observer. For the proposed velocity observer, a linear relationship between position and observation state is constructed, through which the need of solving partial differential and certain integral equations can be avoided. Meanwhile, the mean value theorem is exploited to separate the observation error terms, and hence, all functions in our observer can be analytically expressed. With the estimated velocity information, a slave-torque feedback control law is presented. A novel Lyapunov-Krasovskii functional is constructed to establish asymptotic tracking conditions. In particular, the relationship between the controller design parameters and the allowable maximum delay values is provided. Finally, simulation and experimental results reveal that the proposed velocity observer and controller can guarantee that the observation errors and tracking error converge to zero.      

大时延遥操作系统的波变量双边自适应控制

针对通信时延对遥操作系统稳定性和透明性的影响,研究了一种基于双边自适应控制和波变量理论的控制方法。通过设计波控制器保证通信传输模块的无源性,在保证系统稳定的基础上,调节波阻抗系数来提高系统的透明性,并在时延10 s的情况下进行主从端速度、位置和力的跟踪仿真实验,结果表明该方法和已有的双边自适应方法相比既能保证系统稳定且透明性好,达到较好的控制效果。