Controller Design for a Teleoperation System with Time Delay

A robust controller design method is presented to guarantee the stability and zero tracking error for teleoperation system with time delay. Through choosing appropriate master and slave parameters, extended state equation about master and master-slave error is achieved, which can be analyzed by using time delay knowledge. Thus delay-independent and delay-dependent criteria are derived in terms of the Lyapunov stability theorem, control parameters are obtained by the feasible of linear matrix inequalities. Experimental results show the validity of these approaches and the performance of master and slave manipulators with delay variations is analyzed.

Real-Time Internet-Based Teleoperation

Internet-based teleoperation employs robots and internet a two breakthrough technologies to manipulate robots from distance for different applications. Variable and unknown time delay dynamics of internet is the main obstacle for realtime teleoperation via internet. In this paper the internet delay dynamics and its characteristics have been studied based on the measurement in different nodes. Then a black-box model for end-to-end internet delay dynamics has been developed using system identification and Auto-Regressive eXogeneous (ARX) model. Our experimental studies show a regular periodic behaviour in long-term intervals of internet delay variation and also confirm the accuracy and reliability of our theoretical and modelling derivations. This paper also introduces a novel multivariable control method for real-time telerobotic operations via Internet. Random communications delay of the Internet can cause instability in realtime closed-loop telerobotic systems. When a single identification model is used, it will have to adapt itself to the operating condition before an appropriate control mechanism can be applied. Slow adaptation may result in a large transient error. As an alternative, we propose to use a Multiple Model framework. The control strategy is to determine the best model for the current operating condition and activate the corresponding controller. We propose the use of Multi-Model Adaptive Control Theory and Multivariable Wave prediction method to capture the concurrency and complexity of Internet-based teleoperation. The results confirm the efficiency of the proposed technique in dealing with constant and variable delay dynamics of internet.

A new approach for teleoperation rendezvous and docking with time delay

Teleoperation rendezvous and docking can be used as a backup for autonomous rendezvous and docking (RVD) for an unmanned spacecraft or for guiding the chaser docking with an uncooperative target.The inherent teleoperation time delay is a rigorous problem,especially when the chaser is teleoperated on the ground.To eliminate the effect of time delay,a new approach for teleoperation RVD is studied.The characteristics of teleoperation RVD are analyzed by comparisons with the teleoperation robot and with manually controlled RVD;the relative motion of the chaser is predicted based on the C-W equation;and the processed measure information with time delay through the Kalman filter is utilized to correct the current prediction.Experimental results verify that the approach produces an 18% enhanced success rate of teleoperation RVD compared with direct visual feedback,and consumes less time and fuel.The developed approach also solves the time delay problem effectively.Teleoperation RVD using this method can be applied as a useful backup for autonomous RVD.

Investigation into Pilot Handling Qualities in Teleoperation Rendezvous and Docking with Time Delay

Teleoperation rendezvous and docking can be used as a backup for autonomous rendezvous and docking（RVD） for an unmanned spacecraft when the autonomous system is failure or for guiding the chaser docking with an uncooperative target.The theoretical model for analyzing the handling qualities in teleoperation RVD process is established based on the previous studies conducted by National Aeronautics and Space Administration（NASA）.The predictive factor is introduced to describe the pilot＇s predictive ability in the teleoperation tasks with time delay,which interrelates with the skills of a pilot and the predictive assist approach used in the tasks such as the predictive display method.Based on the semi-physical simulation system in our laboratory,900 experiments at two levels of time delay are carried out by 18 volunteers for validating the established model.The experimental results demonstrate the correctness of the theoretical model and indicate that a skilled pilot has a predictive ability of approximately 0.9 in teleoperation RVD tasks.The theoretical analysis shows that the handling qualities are greatly affected by the time delay and the predictive factor,and it is impossible to achieve a teleoperation RVD task for the skilled pilot when the time delay is larger than 9.0 s.

A new impedance and robust adaptive inverse control approach for a teleoperation system with varying time delay

This paper presents a new robust adaptive inverse control approach for a force-reflecting teleoperation system with varying time delay. First,an impedance control is designed for the master robot. Second,an adaptive inverse control is proposed for the slave robot. Finally,the slave side controller is modified such that the robust stability and performance are achieved. In addition,robust stability analysis has been performed and optimal behavior is ensured by using standard characteristic polynomials. It is shown that despite of presence of randomly-varying time delay,the proposed control algorithm compensates the position drifts efficiently. Demonstrable simulation studies confirm the effectiveness of the proposed control system and its advantages over the existing sliding mode control strategies.

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.

A novel control framework for internet based tele-robotics

Aiming at the tele-operation instability caused by time delay of interuet information transfer for internet based tele-robotics, this paper proposes a novel control framework for internet based tele-roboties, which can guarantee the non-distortion-transfer of control information and reduce the difference of action time between the local simulated virtual robot and the remote real robot. This framework is insensitive to the inherent interact time delay, and differs from other tele-robotics systems that try to use some mathematic models to describe the internet delay or take some assumptions. In order to verify the framework, a 4-DOF fischertechnik industry robot tele-operation system has been developed using the new proposed framework. Experimental results demonstrate the applicable performance of the new framework. The framework is open structured and can be applied to other general purposed tele-operation systems.

Control Schemes for Passive Teleoperation Systems over Wide Area Communication Networks with Time Varying Delay

In this paper,the problem of time varying telecommunication delays in passive teleoperation systems is addressed.The design comprises delayed position,velocity and position-velocity signals with the local position and velocity signals of the master and slave manipulators.Nonlinear adaptive control terms are employed locally to cope with uncertain parameters associated with the gravity loading vector of the master and slave manipulators.Lyapunov-Krasovskii function is employed for three methods to establish asymptotic tracking property of the closed loop teleoperation systems.The stability analysis is derived for both symmetrical and unsymmetrical time varying delays in the forward and backward communication channel that connects the local and remote sites.Finally,evaluation results are presented to illustrate the efectiveness of the proposed design for real-time applications.

Delayed Teleoperation with Force Feedback of a Humanoid Robot

Teleoperation systems allow the extension of human capabilities to remote-control devices by providing the operator with conditions similar to those at the remote site through a communication channel that sends information from one site to the other. This article aims to present an analysis of the benefits of force feedback applied to the bilateral teleoperation of a humanoid robot with timevarying delay. As a control scheme, we link adaptive inverse dynamics compensation, balance control, and P+d like controllers. Finally,a test is performed where an operator simultaneously handles the locomotion(forward velocity and turn angle) and arm of a simulated 3D humanoid robot to do a pick-and-place task using two master devices with force feedback, where indexes such as time to complete the task, coordination errors, path tracking error, and percentage of successful tests are reported for different time-delays. We conclude with the results achieved.

Gender difference in network relationship between inter-temporal decisions and prefrontal activation levels in internet gaming disorder

Background:Impulsivity and decision-making are key factors in addiction.However,little is known about how gender and time sensitivity affect impulsivity in internet gaming disorder(IGD).Objective:To investigate the gender difference of impulsive decision-making and relevant brain responses in IGD.Methods:We conducted a functional magnetic resonance imaging(fMRI)study with 123 participants,including 59 IGD individuals(26 females)and 64 matched recreational game users(RGUs,23 females).Participants performed a delay-discounting task during fMRI scanning.We examined gender-by-group effects on behavioral and neural measures to explore the preference for immediate over delayed rewards and the associated brain activity.We also investigated the network correlations between addiction severity and behavioral and neural measures,and analyzed the mediating role of brain activity in the link between delay discounting parameters and IGD severity.Results:We found significant gender-by-group interactions.The imaging results revealed gender-by-group interactions in the dor-solateral prefrontal cortex,medial frontal gyrus,and inferior frontal gyrus(IFG).Post hoc analysis indicated that,for females,RGUs showed higher activity than IGD individuals in these brain regions,while for males IGD individuals exhibited higher activity than RGUs.The activation in the left IFG mediated the relation between Internet Addiction Test score and discount rate in females.In males,the activation in the right dlPFC mediated the relation between IAT score and time sensitivity.Discussion:Our findings imply that male IGD participants demonstrate impaired intertemporal decisions associated with neural dysfunction.Influencing factors for impulsive decision-making in IGD diverge between males(time sensitivity)and females(discount rate).These findings augment our comprehension of the neural underpinnings of gender differences in IGD and bear significant implications for devising effective intervention strategies for treating people with IGD.

Force-reflecting teleoperation of robots based on on-line correction of a virtual model

Virtual reality is an effective method to eliminate the influence of time delay.However,it depends on the precision of the virtual model.In this paper,we introduce a method that corrects the virtual model on-line to establish a more precise model.The geometric errors of the virtual model were corrected on-line by overlapping the graphics over the images and also by syncretizing the position and force information from the remote.Then the sliding average least squares(SALS)method was adopted to determine the mass,damp,and stiffness of the remote environment and use this information to amend the dynamic model of the environment.Experimental results demonstrate that the on-line correction method we proposed can effectively reduce the impact caused by time delay,and improve the operational performance of the teleoperation system.

基于Internet的机器人控制中网络时延测试及分析

本文针对基于 Internet的机器人控制 ,首先分析了 Internet网络时间延迟的主要组成及其基本特性 ,然后介绍了网络时延测试实验的结果及其结论 ,最后研究了网络时延预估算法及其有效性.

基于Internet力觉临场感遥操作机器人系统的研究

虽然Internet技术扩大了遥操作机器人系统的应用范围,同时也带来了新的问题——时延。针对不同性质的时延本文综述了基于Internet力觉临场感遥操作机器人系统的国内外发展状况、系统构成以及为解决时延问题提出的遥操作系统的主要控制方法并指出了各方法的优缺点,最后展望了其发展前景。

Bus Arrival Time Prediction Based on Mixed Model

How to predict the bus arrival time accurately is a crucial problem to be solved in Internet of Vehicle. Existed methods cannot solve the problem effectively for ignoring the traffic delay jitter. In this paper,a three-stage mixed model is proposed for bus arrival time prediction. The first stage is pattern training. In this stage,the traffic delay jitter patterns(TDJP)are mined by K nearest neighbor and K-means in the historical traffic time data. The second stage is the single-step prediction,which is based on real-time adjusted Kalman filter with a modification of historical TDJP. In the third stage,as the influence of historical law is increasing in long distance prediction,we combine the single-step prediction dynamically with Markov historical transfer model to conduct the multi-step prediction. The experimental results show that the proposed single-step prediction model performs better in accuracy and efficiency than short-term traffic flow prediction and dynamic Kalman filter. The multi-step prediction provides a higher level veracity and reliability in travel time forecasting than short-term traffic flow and historical traffic pattern prediction models.

A multi-resource scheduling scheme of Kubernetes for IIoT

With the rapid development of data applications in the scene of Industrial Internet of Things(IIoT),how to schedule resources in IIoT environment has become an urgent problem to be solved.Due to benefit of its strong scalability and compatibility,Kubernetes has been applied to resource scheduling in IIoT scenarios.However,the limited types of resources,the default scheduling scoring strategy,and the lack of delay control module limit its resource scheduling performance.To address these problems,this paper proposes a multi-resource scheduling(MRS)scheme of Kubernetes for IIoT.The MRS scheme dynamically balances resource utilization by taking both requirements of tasks and the current system state into consideration.Furthermore,the experiments demonstrate the effectiveness of the MRS scheme in terms of delay control and resource utilization.

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Internet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。

遥操作机器人系统的变时延控制

由于遥操作机器人传输通道中存在着变化的通讯时延,造成了系统不稳定和操作性能降低等问题。为了消除或减少时延的影响,在利用RBF神经网络进行延时预测的基础上,通过改进型Smith预估器进行遥操作机器人的时延控制,从而使系统稳定,并易于操作。理论分析表明,该方案对时延的变化有较强的适应性,控制系统的鲁棒稳定性和动态品质均优于单纯的Smith预估补偿控制,且易于实现。仿真结果表明,在时延情况下,该方法可实现对遥操作机器人较为准确的测控。

力觉临场感遥操作系统的研究进展

力觉临场感遥操作机器人系统是一种新型的机器人控制系统 ,目前研究中系统存在的控制通信时延是严重影响系统的操作性能、甚至使系统不稳定的主要原因之一。当利用Internet网络传输信号时 ,时延是时变的、不确定的 ,对系统的影响更为明显。因此意在介绍国内外力觉临场感遥操作机器人系统的发展状况以及在克服时延对系统影响方面所取得的最新研究进展 ,同时指出研究中存在的问题 ,及对进一步研究提出一些看法。

网络机器人遥操作系统设计与实现

本文在分析了网络环境下机器人遥操作系统的结构的基础上,介绍了一套基于网络的移动机器人遥操作实验系统的设备组成及硬软件结构的设计和实现。系统设计简洁有效,网络虚拟机的设计和使用则极大地方便了遥操作研究的开展。

Software defined industrial network architecture for edge computing offloading

The integration of the Internet and the traditional manufacturing industry makes the industrial Internet of things(IIoT) as a popular research topic. However, traditional industrial networks continue to face challenges of resource management and limited raw data storage and computation capacity. A novel software defined industrial network(SDIN) architecture was proposed to address the existing drawbacks in IIoT such as resource utilization, data processing and storage, and system compatibility. The architecture is developed based on the software defined network(SDN) architecture, combining hierarchical cloud and fog computing and content-aware caching technologies. Based on the SDIN architecture, two types of edge computing strategies in industrial applications are discussed. Different scenarios and service requirements are considered. The simulation results confirm that the SDIN architecture is feasible and effective in the application of edge computing offloading.