In genetic regulatory networks (GRNs), gene mutations often occur in a stochastic manner. As an important model of GRNs, gene mutations of Boolean networks are always described as function ...perturbations. This article studies the robust stability and stabilization of Boolean networks with stochastic function perturbations. A kind of parameterized set is constructed, and it is revealed that under the stochastic function perturbations, the property of finite-time stability remains unchanged when the perturbed set and the parameterized set are disjoint. In addition, it is proved that the finite-time stability is reduced to stability in distribution when the intersection of perturbed set and complement set of parameterized set is nonempty. As an application, the robust stabilization problem of Boolean control networks with stochastic function perturbations is discussed, and several necessary and sufficient conditions are presented for the robustness of feedback stabilizers. Finally, the obtained results are used to study the Drosophila melanogaster segmentation polarity gene network and the lac operon in the bacterium Escherichia coil.
We consider a setup where a distributed set of sensors working cooperatively can estimate an unknown signal of interest, whereas any individual sensor cannot fulfill the task due to lack of necessary ...information diversity. This article deals with these kinds of estimation and tracking problems and focuses on a class of simultaneous perturbation stochastic approximation (SPSA)-based consensus algorithms for the cases when the corrupted observations of sensors are transmitted between sensors with communication noise and the communication protocol has to satisfy a prespecified cost constraints on the network topology. Sufficient conditions are introduced to guarantee the stability of estimates obtained in this way, without resorting to commonly used but stringent conventional statistical assumptions about the observation noise, such as randomness, independence, and zero mean. We derive an upper bound of the mean square error of the estimates in the problem of unknown time-varying parameters tracking under unknown-but-bounded observation errors and noisy communication channels. The result is illustrated by a practical application to the multisensor multitarget tracking problem.
Transparency and guaranteed safety are important requirements in the design of wearable exoskeleton actuators for individuals who have lower limb deficits but still maintain a certain level of ...voluntary motor control. Specifically, precision in torque delivery timing and magnitude, robustness, disturbance rejection, and repeatability are desired in the actuator design and control. Motivated by these needs, this study aims to develop a series of elastic actuators with clutch (SEAC) that can precisely generate the desired assistance in terms of both timing and torque magnitude for a wearable hip exoskeleton and guarantee the wearer's safety at the same time. The proposed mechanical design improves actuator transparency and safety by a mechanical clutch that automatically disengages the transmission when needed. A new torque control for the SEAC, based on singular perturbation theory with flexible compensation techniques, is proposed to precisely control the assistive torque by rejecting the undesired human motion disturbance. The mechanical design of the proposed device and the design of a singular perturbation control algorithm are discussed, and the SEAC performance is verified by experiments. Experimental results, derived from a test with a human subject, are presented to demonstrate the precision of the assistive torque and timing control of the SEAC while interacting with a human wearer.
Perturbation Analysis of Evidential Reasoning Rule Tang, Shuai-Wen; Zhou, Zhi-Jie; Hu, Chang-Hua ...
IEEE transactions on systems, man, and cybernetics. Systems,
2021-Aug., 2021-8-00, Letnik:
51, Številka:
8
Journal Article
Recenzirano
Evidential reasoning (ER) rule has been widely used in addressing uncertainty, ignorance, and vagueness information. To explore its performance measure (PM), the perturbation analysis (PA) for the ER ...rule (ER rule-PA) is conducted, with perturbation taken into consideration. This article aims to analyze the robustness and stability of the ER rule, serving as theoretical basis and technical support for applied research and applications. The combination of two pieces of independent evidence is discussed, and perturbation is added to one piece of evidence. To represent the expected utility of evidence combination under perturbation, perturbation utility is introduced. The novel concept of perturbation coefficient is proposed to characterize the PM of the ER rule (ER rule-PM). The properties of perturbation coefficient are explored to demonstrate the impact of perturbation. The maximum permissible error (MPE) of perturbation coefficient is defined to characterize the acceptability of perturbation. A numerical study is examined to illustrate the implementation process of ER rule-PA. Moreover, a case study of reliability evaluation of aerospace relay is conducted to show the potential applications of ER rule-PA, which makes the proposed method more practical.
This letter presents a perturbation estimation based robust load frequency control (LFC) scheme for power system subject to random time-delay attack. Perturbation term is defined to describe the ...measurement deviation caused by random time-delay attack. Besides, perturbation observer is designed to estimate the system perturbation. The load frequency controller is compensated based on the perturbation estimation to mitigate the random time-delay attack and ensure the stable operation of power system. Case studies are undertaken on a two-area LFC model to demonstrate the control performance of the scheme.
Although the flight control of quadrotor unmanned aerial vehicles have been widely studied, it is still very challenging to suppress multiple disturbances and efficiently utilize the inherent multi ...time-scale characteristics. As a well-known antidisturbance strategy, composite hierarchical antidisturbance control (CHADC) can compensate and attenuate disturbances simultaneously, thus enhancing the control performance of complex systems significantly. In the meantime, the singular perturbation theory (SPT) is employed to analyze the multi time-scale properties, and the original system is decomposed into the slow and fast subsystems. In this article, we present an antidisturbance control scheme based on the SPT and CHADC to enhance the capability of antidisturbance. A novel composite hierarchical antidisturbance (CHAD) predictor-corrector is proposed for the slow subsystem to integratively handle the disturbances from guidance and control perspective, and a CHAD <inline-formula><tex-math notation="LaTeX">{{H}_{\infty }}</tex-math></inline-formula> controller is employed for the fast subsystem subject to external disturbances and inertial uncertainties. Meanwhile, the compensability of disturbance is explicitly analyzed. Finally, experiments are carried out to validate the effectiveness of the proposed scheme.
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