Delayed Feedback Control in Bilateral Teleoperation

Author(s):  
Naci Zafer

Stabilization of time delay systems is currently a mainstream of research. In this paper, a delayed feedback controller is considered for internet-based teleoperation, where the master and the slave manipulators are bilaterally connected through a communication channel. A frequency based approach is employed for the stability analysis of teleoperation in spite of varying time delays. The derived approach is exact in telling weather the system is stable, whenever the system parameters including the delay are prescribed. The analysis formulates the stability intervals as delay varies. It is also shown how delayed negative feedback is able to stabilize oscillatory system dynamics. The results are illustrated with numerical examples.

2006 ◽  
Vol 16 (10) ◽  
pp. 2935-2947 ◽  
Author(s):  
JIANDONG ZHU ◽  
YU-PING TIAN

This paper considers stabilization of unstable periodic solutions of nonlinear systems. Based on differential geometry method, a nonlinear recursive delayed feedback controller is designed. The concept of γ dynamics is introduced and the stability of the periodic solution of the closed-loop system is proved rigorously. The proposed control method does not have the odd number limitation. Simulation results are also presented for validating the effectiveness of the proposed method.


Robotica ◽  
2014 ◽  
Vol 34 (4) ◽  
pp. 859-875 ◽  
Author(s):  
Da Sun ◽  
Fazel Naghdy ◽  
Haiping Du

SUMMARYStability and transparency are two critical indices of bilateral teleoperation systems. The wave variable method is a conservative approach to robustly guarantee system passivity under arbitrary constant time delays. However, the wave-variable-based reflection is an intrinsic problem in this method because it can significantly degrade system transparency and disorient the operator's perception of the remote environment. In order to enhance both the transparency and the stability of bilateral teleoperation systems in the presence of large time delays, a new four-channel (4-CH) architecture is proposed which applies two modified wave-transformation controllers to reduce wave-based reflections. Transparency and stability of the proposed system are analyzed and the improvement in these when using this method is measured experimentally. Results clearly demonstrate that the proposed method can produce high transparency and stability even in the presence of large time delays.


Author(s):  
Fadi Alsaleem ◽  
Mohammad I. Younis

In this work, we investigate the stability and integrity of parallel-plate microelectromechanical systems resonators using a delayed feedback controller. Two case studies are investigated: a capacitive sensor made of cantilever beams with a proof mass at their tip and a clamped-clamped microbeam. Dover-cliff integrity curves and basin-of-attraction analysis are used for the stability assessment of the frequency response of the resonators for several scenarios of positive and negative gain in the controller. It is found that in the case of a positive gain, a velocity or a displacement feedback controller can be used to effectively enhance the stability of the resonators. This is confirmed by an increase in the area of the basin of attraction of the resonator and in shifting the Dover-cliff curve to higher values. On the other hand, it is shown that a negative gain can significantly weaken the stability and integrity of the resonators. This can be of useful use in MEMS for actuation applications, such as in the case of capacitive switches, to lower the activation voltage of these devices and to ensure their trigger under all initial conditions.


Author(s):  
Wei Dong ◽  
Ye Ding ◽  
Luo Yang ◽  
Xinjun Sheng ◽  
Xiangyang Zhu

This paper presents an accurate and computationally efficient time-domain design method for the stability region determination and optimal parameter tuning of delayed feedback control of a flying robot carrying a suspended load. This work first utilizes a first-order time-delay (FOTD) equation to describe the performance of the flying robot, and the suspended load is treated as a flying pendulum. Thereafter, a typical delayed feedback controller is implemented, and the state-space equation of the whole system is derived and described as a periodic time-delay system. On this basis, the differential quadrature method is adopted to estimate the time-derivative of the state vector at concerned sampling grid point. In such a case, the transition matrix between adjacent time-delay duration can be obtained explicitly. The stability region of the feedback system is thereby within the unit circle of spectral radius of this transition matrix, and the minimum spectral radius within the unit circle guarantees fast tracking error decay. The proposed approach is also further illustrated to be able to be applied to some more sophisticated delayed feedback system, such as the input shaping with feedback control. To enhance the efficiency and robustness of parameter optimization, the derivatives of the spectral radius regarding the parameters are also presented explicitly. Finally, extensive numeric simulations and experiments are conducted to verify the effectiveness of the proposed method, and the results show that the proposed strategy efficiently estimates the optimal control parameters as well as the stability region. On this basis, the suspended load can effectively track the pre-assigned trajectory without large oscillations.


2012 ◽  
Vol 22 (06) ◽  
pp. 1250147 ◽  
Author(s):  
KE DING ◽  
QING-LONG HAN

Some mathematical models in engineering and physics, such as rotating pendulums, governors and phase locked loops in circuits, can be described as nonautonomous systems in which there exist chaotic attractors. This paper investigates master-slave synchronization for two nonautonomous chaotic systems by using time-delayed feedback control. Firstly, three delay-dependent synchronization criteria, which are formulated in the form of linear matrix inequalities (LMIs), are established for complete synchronization, lag synchronization and anticipating synchronization, respectively. Secondly, sufficient conditions on the existence of a time-delayed feedback controller are derived by employing these newly-obtained synchronization criteria. The controller gain can be obtained by solving a set of LMIs. Finally, the synchronization criteria and the design method are applied to master-slave synchronization for rotating pendulum systems.


2015 ◽  
Vol 25 (06) ◽  
pp. 1550087 ◽  
Author(s):  
Zhichao Jiang ◽  
Wanbiao Ma

In this paper, the effect of delay on a nonlinear chaotic chemostat system with delayed feedback is investigated by regarding delay as a parameter. At first, the stability of the positive equilibrium and the existence of Hopf bifurcations are obtained. Then an explicit algorithm for determining the direction and the stability of the bifurcating periodic solutions is derived by using the normal form theory and center manifold argument. Finally, some numerical simulation examples are given, which indicate that the chaotic oscillation can be converted into a stable steady state or a stable periodic orbit when delay passes through certain critical values.


2015 ◽  
Vol 25 (05) ◽  
pp. 1550074 ◽  
Author(s):  
Lingling Zhang ◽  
Jianhua Huang ◽  
Lihong Huang ◽  
Zhizhou Zhang

This paper considers the time-delayed feedback control for Maglev system with two discrete time delays. We determine constraints on the feedback time delays which ensure the stability of the Maglev system. An algorithm is developed for drawing a two-parametric bifurcation diagram with respect to two delays τ1 and τ2. Direction and stability of periodic solutions are also determined using the normal form method and center manifold theory by Hassard. The complex dynamical behavior of the Maglev system near the domain of stability is confirmed by exhaustive numerical simulation.


2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Jianping Shi ◽  
Liyuan Ruan

Abstract In this paper, we study the reasonability of linearized approximation and Hopf bifurcation control for a fractional-order delay Bhalekar–Gejji (BG) chaotic system. Since the current study on Hopf bifurcation for fractional-order delay systems is carried out on the basis of analyses for stability of equilibrium of its linearized approximation system, it is necessary to verify the reasonability of linearized approximation. Through Laplace transformation, we first illustrate the equivalence of stability of equilibrium for a fractional-order delay Bhalekar–Gejji chaotic system and its linearized approximation system under an appropriate prior assumption. This semianalytically verifies the reasonability of linearized approximation from the viewpoint of stability. Then we theoretically explore the relationship between the time delay and Hopf bifurcation of such a system. By introducing the delayed feedback controller into the proposed system, the influence of the feedback gain changes on Hopf bifurcation is also investigated. The obtained results indicate that the stability domain can be effectively controlled by the proposed delayed feedback controller. Moreover, numerical simulations are made to verify the validity of the theoretical results.


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