scholarly journals Oscillations in First-Order, Continuous-Time Systems via Time-Delay Feedback

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-14
Author(s):  
Abimael Salcedo ◽  
Joaquin Alvarez
Keyword(s):  
Continuous Time ◽  
Closed Loop ◽  
Equilibrium Points ◽  
Nonlinear Function ◽  
Loop System ◽  
Closed Loop System ◽  
First Order ◽  
Continuous Time Systems ◽  
Time Systems ◽  
Order Continuous

A technique to generate (periodic or nonperiodic) oscillations systematically in first-order, continuous-time systems via a nonlinear function of the state, delayed by a certain time d, is proposed. This technique consists in choosing a nonlinear function of the delayed state with some passivity properties, tuning a gain to ensure that all the equilibrium points of the closed-loop system be unstable, and then imposing conditions on the closed-loop system to be semipassive. We include several typical examples to illustrate the effectiveness of the proposed technique, with which we can generate a great variety of chaotic attractors. We also include a physical example built with a simple electronic circuit that, after applying the proposed technique, displays a similar behavior to the logistic map.

Fuzzy fault-tolerant containment control for multi-agent systems with unknown nonlinear dynamics

2021 ◽  
pp. 014233122110430
Author(s):  
Malika Sader ◽  
Fuyong Wang ◽  
Zhongxin Liu ◽  
Zengqiang Chen
Keyword(s):  
Closed Loop ◽  
Control Method ◽  
Fault Tolerant ◽  
Nonlinear Function ◽  
Loop System ◽  
Multi Agent Systems ◽  
Closed Loop System ◽  
Containment Control ◽  
Agent Systems ◽  
Multi Agent

This paper studies the containment control problem for a class of nonlinear multi-agent systems (MASs) with actuator faults (AFs) and external disturbance under switching communication topologies. To address this problem, a new fuzzy fault-tolerant containment control method is developed via utilizing adaptive mechanisms. Furthermore, a sufficient condition is obtained to guarantee the stability of the considered closed-loop system by the dwell time technique combined with Lyapunov stability theory. Unlike the traditional method to estimate the weight matrix, the fuzzy logic system is used to estimate the norm of weight vectors. Thus, the difficulty that the unknown nonlinear function cannot be compensated for when the actuator produces outage or stuck fault is solved. Compared with the existing controllers for nonlinear MASs, the proposed controller is more suitable for the considered problem under the influence of AFs that are detrimental to the operation of each agent system. Besides which, the closed-loop system is proven to be stable by using the developed controller, and all followers converge asymptotically to the convex hull formed by the leaders. Finally, an example based on a reduced-order aircraft model is presented to verify the effectiveness of the designed control scheme.

scholarly journals Analytical Tuning Method of MPC Controllers for MIMO First-Order Plus Fractional Dead Time Systems

Processes ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 212
Author(s):  
Ning He ◽  
Yichun Jiang ◽  
Lile He
Keyword(s):  
Predictive Control ◽  
Closed Loop ◽  
Dead Time ◽  
Pole Placement ◽  
Closed Loop System ◽  
Placement Problem ◽  
First Order ◽  
Tuning Method ◽  
Domain Performance ◽  
Time Systems

An analytical model predictive control (MPC) tuning method for multivariable first-order plus fractional dead time systems is presented in this paper. First, the decoupling condition of the closed-loop system is derived, based on which the considered multivariable MPC tuning problem is simplified to a pole placement problem. Given such a simplification, an analytical tuning method guaranteeing the closed-loop stability as well as pre-specified time-domain performance is developed. Finally, simulation examples are provided to show the effectiveness of the proposed method.

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