FPAA-based control of bilateral teleoperation systems

Bilateral teleoperation systems have been widely applied for human operators to manipulate slave robots in accomplishing various tasks within remote environments. However, most teleoperation systems developed previously have heavily relied on continuous communication or a network with higher sampling rates. In this study, the authors propose novel control schemes to guarantee stability and tracking performance of bilateral teleoperation by considering an event-based transmission. Based on local output signals and the proposed triggering mechanisms, the master and slave robots transmit signals over a communication network only when the triggering conditions are satisfied. An event-triggered coordinating controller is presented to guarantee stability and position tracking for non-linear teleoperators. Input-to-state stability of the proposed teleoperation system with bounded external forces is studied with guaranteed static force reflection. Subsequently, a transformation-based framework is addressed with the event-triggered coordinating control to cope with bilateral teleoperation systems under time delays. The Zeno behaviour is demonstrated to be excluded in the proposed event-triggered teleoperation systems. Numerical examples and experiments are presented to discuss the efficacy of the proposed event-triggered teleoperation systems.

The control problem for bilateral teleoperation systems using only one controller is studied in this paper. In the proposed control framework, the remote robot transmits position/velocity signals to the controller located with the local robot. The corresponding control inputs for local and remote robots are obtained from the same controller. The individual control signal is sent to the local robot directly, and transmitted to the remote robot over a network subject to communication delays. Two control algorithms, P-like and PD-like controllers, are considered in the novel bilateral teleoperation system framework. Stability and tracking performance can be guaranteed if control gains are contingent to time delays when the external force are passive or both robots are in free motion. Numerical examples are presented to validate the performance of the proposed bilateral teleoperation control systems.

Bilateral teleoperation control systems are designed for guaranteed stability against uncertainties in operator and environment dynamics. In this paper, we study the effect of human operator dynamics on the coupled stability by incorporating the operator dynamics in the master–slave network. We will analytically prove and graphically show that for any potentially unstable control architecture, as the operator minimum damping grows, the teleoperation system can stably tolerate a larger range of variations in the environment impedance parameters. More importantly, we will demonstrate how the proposed coupled stability analysis method can be utilized to design stabilizing controllers for enhanced transparency, given a priori knowledge or online estimate of human operator damping.

In this paper, motion synchronization control of bilateral tele-operation system is investigated. Compared with previous passivity framework, the communication delays are assumed to be stochastic time-varying. By feedback linearization, the nonlinear dynamics of the tele-operation system is transformed into two linear sub-systems: local master/slave position control and delayed motion synchronization. We propose new control strategies based on linear matrix inequalities (LMI) and Markov jump linear systems, which guarantees ultimate boundedness of the master/slave trajectories. By choosing Lyapunov Krasovskii functional, we show that the master-slave tele-operation system is asymptotically stable under specific LMI conditions. Finally, the simulations are performed to show the effectiveness of the proposed method.

In this study, motion synchronisation control of bilateral teleoperation system is investigated. Compared with previous passivity framework, the communication delays are assumed to be stochastically time varying. By feedback linearisation, the non-linear dynamics of the teleoperation system is transformed into two linear subsystems: local master-slave position control and delayed motion synchronisation. The authors propose new control strategies based on linear matrix inequalities (LMIs) and Markov jump linear systems, which guarantees ultimate boundedness of the master-slave trajectories. With Lyapunov methods, they show that the master-slave teleoperation system is stochastically stable in mean square under specific LMI conditions. Finally, the simulations are performed to show the effectiveness of the proposed method.

The adaptive control of bilateral teleoperation system under denial of service (DoS) attacks is studied in this letter. The model of bilateral teleoperation system under DoS attacks is presented. The adaptive controllers are designed to deal with the influence of data missing caused by packet dropouts and DoS attacks. Two Bernoulli distributed variables are introduced to describe the system dynamic for the case that both packet dropouts and DoS attacks are involved in the communication channels. The globally asymptotically stability criterion is proposed by using Lyapunov functional methods, which implies the dynamics of the Master and the Slave are globally asymptotically synchronized. A numerical example of two degree of freedom bilateral teleoperation system is provided to show the effectiveness of obtained results.

PurposeThis paper aims to use the adaptive computed torque control (ACTC) method to eliminate the kinematic and dynamic uncertainties of master and slave robots and for the control of the system in the presence of forces originating from human and environment interaction.Design/methodology/approachIn case of uncertainties in the robot parameters that are utilized in teleoperation studies and when the environment where interactions take place is not known and when there is a time delay, very serious problems take place in system performance. An adaptation rule was created to update uncertain parameters. In addition to this, disturbance observer was designed for slave robot. Lyapunov function was used to analyze the system’s position tracking and stability. A visual interface was designed to ensure that the movements of the master robot provided a visual feedback to the user.FindingsIn this study, a visual interface was created, and position and velocity control was achieved utilizing teleoperation; the system’s position tracking and stability were analyzed using the Lyapunov method; a simulation was applied in a real-time environment, and the performance results were analyzed.Originality/valueThis study consisted of both simulation and real-time studies. The teleoperation system, which was created in a laboratory environment, consisted of six-degree-of-freedom (DOF) master robots, six-DOF industrial robots and six-DOF virtual robots.

Synchronization control for bilateral teleoperation system with position error constraints: A fixed-time approach

This paper evaluates the performance of a new control scheme for bilateral master-slave teleo- perator, introduced earlier, and compares it to pub- lished control methods by using a mathematical cri- terion based on the two-port network model. It is shown that most of the published control laws under investigation do not achieve optimal performance, and the few that do, require perfect estimation (or exact knowledge) of the human operator or master arm dynamics. It is also shown that optimal performance, based on the selected mathematical criterion, can be obtained using the proposed control law: I. INTRODUCTION Teleoperating systems may be viewed as synergistic systems composed of human operators and master-slave manipulators which interact with the physical world. The master, sometimes called hand controller, is used to gen- erate commands (usually position, rate or force commands) to its remotedly located counterpart called slave. In gen- eral, the position/velocity command from the operator is fed forward to the slave, while the reaction force, due to mechanical interaction with the environment, is fed back to the master, providing contact force information to the human operator. By reflecting the measured force back to the master arm, it is said that the teleoperator is controlled bilaterally. One of the main issues in telerobotics is control of master-slave teleoperators. A number of control metho- dologies have been proposed in the teleoperator literature. There are two main methods for controlling master-slave teleoperators. The first, a more traditional approach, uses position and/or velocity error (between the master and slave) to generate a forcehorque command into the master arm. The position/velocity of the master and slave are measured by sensors usually located at the joints. The second method uses direct force feedback, rather than posi- tion and velocity errors, to generate command signals to the master. This method uses a force/torque signal obtained from a sensor, usually located at the end-effector of the slave, to provide the operator with the force feeling of the remotedly located counterpart. The force feedback control is usually considered superior because of the more precise nature of the feedback signal. The two-port model network theory has been exten- sively used for the analysis of circuits in which bi- directional energy flows are present at two distinct pairs of terminals. This method provides a useful linear representa- tion of complex networks which exchange energy. The two-port model theory is also used in bilateral teleoperator systems (1,3-81, with force and velocity sensing at the mas- ter and slave. The interfaces between the human operator and master, and between the environment and slave are ports through which the teleoperator is designed to exchange energy between the operator and environment. Recently, several algorithms have been proposed to

Communication time delays in a bilateral teleoperation system often carries a stochastic nature, particularly when we have multiple masters or slaves. In this paper, we tackle the problem for a single-master multislave (SMMS) teleoperation system by assuming an asymmetric and semi-Markovian jump protocol for communication of the slaves with the master under time-varying transition rates. A nonlinear robust controller is designed for the system that guarantees its global robust H∞ stochastic stability in the sense of the Lyapunov theory. Employing the nonlinear feedback linearization technique, the dynamics of the closed-loop teleoperator is decoupled into two interconnected subsystems: 1) master-slave tracking dynamics (coordination) and 2) multislave synchronization dynamics. Employing an improved reciprocally convex combination technique, the stability analysis of the closed-loop teleoperator is conducted using the Lyapunov-Krasovskii methodology, and the stability conditions are expressed in the form of linear matrix inequalities that can be solved efficiently using numerical algorithms. Numerical studies and simulation results validate the effectiveness of the proposed controller design algorithm in both tracking and synchronization performance of the SMMS system, and robustly handling the stochastic and nondifferentiable nature of communication delays.

In this paper, adaptive control is proposed for hybrid position/force synchronization of master-slave teleoperation systems with time-varying delays in communication channels. Different from previous works on bilateral teleoperation systems, we investigate position/force control of bilateral teleoperation systems subject to time-varying delays and dynamical uncertainties. Using partial feedback linearization, the dynamics of both master and slave are transformed into two subsystems: local master/slave position/force control with unmodeled dynamics and delayed position/force synchronization. An adaptive control is proposed to deal with the dynamical uncertainties and robust against time delays, which guarantees the position/force synchronization trajectories converge to the desired manifolds with prescribed performance. The stability of the closed-loop system and the boundedness of synchronization tracking errors are proved using linear matrix inequalities based on Lyapunov stability synthesis. The position/force tracking error up to an ultimately bounded error is achieved. The proposed adaptive controls are robust against relative motion disturbances, parametric uncertainties, and time delays, and are validated by experimental studies.

This paper proposes a control scheme based on combining a PD-like structure and a sliding mode control (SMC) applied to mobile robot bilateral teleoperation systems, in the face of asymmetric and time-varying delays. The proposal includes on the remote site both a P+d control and an SMC strategy in such a way that the advantages of both methods are exploited. The system stability is analyzed using Lyapunov-Krasovskii functionals and a delaydependent stability criteria is obtained using linear-matrix-inequalities (LMI). Finally, the teleoperation system is evaluated through human-in-the-loop experiments to confirm the theoretical results and test the robustness and stability of the proposed control scheme.

In this paper, the problem of stability and tracking performance of FRVF (Forbidden Region Virtual Fixture) for bilateral nonlinear teleoperation systems is studied in presence of varying time delay. It is proved that PD-like controllers can stabilize the teleoperation systems with FRVF in slave side and variable time delay in communication channels. It is also proved by proposed Lyapunov-Krasovskii's function that the mentioned problem of stability and tracking performance of FRVF is satisfied. Finally, the proficiency of this approach is demonstrated by simulating the method on a pair of 6-DOF (Degree of Freedom) PHANToM Omni robots with nonlinear dynamics. Keywords— Virtual fixture; variable delay; delayed teleoperation system; nonlinear teleoperation.

Feedback control for the active noise cancellation can be done with analog or digital circuitry. Although digital approach is steadily gaining ground, analog control still has its uses. Short control latency is the feature of an analog controller—it has the shortest possible delay. Its drawback is the limited flexibility for adjustable or adaptive solutions. To overcome this, digitally adjustable analog controllers can be used. A potential implementation for such controller uses field programmable analog array (FPAA) technology. With FPAAs both the filter parameters and structure are digitally adjustable, even during the operation. A development environment around the FPAA controller has been devised. It consists of the measurement system, an optimizer that calculates the optimum controller response, programming software, and actual FPAA hardware with its embedded software. The complete system is packaged tightly to a compact form. It can be used for evaluation purposes in acoustics laboratory conditions. Such a system has been evaluated in active noise insulation application. It has proven to operate as simulated and optimized also in real-world tests. The future development of the system includes further miniaturization, controller networking, and possible integration inside the sound insulation system.

This paper explores the role of haptics in wireless communication and bilateral system to improve the development on bilateral teleoperation system in the future. The telecommunication applications in haptic is to separate between master and slave control in various distances. This purpose is commonly used in medical surgery between different countries or buildings. This technology helps to analyse medical disease and remote human life. In addition, this paper first reviews about Wi-Fi offloading technique comparison between cellular network and Wi-Fi network to achieve ideal connectivity within long range distance. Mobile Node (MN) are the main factor in wireless communication to obtain minimum time delay are also been reviewed in this paper. Apart with telecommunication studies, there are several parameter need to be control comparatively noise ratio, signal strength and signal power was put forward in this paper. Secondly, the implementation of Disturbance Observer between master and slave control and receive the tactile feedback in various fields. DOB control the closed loop system consists of main feedback on the effects of dynamic uncertainties and external disturbances into a single disturbance term in the teleoperation system.