In this paper, the model reference adaptive control (MRAC) method along with a state feedback controller is employed for synchronizing NFSCV, a complex nonlinear fractional-order stochastic model of the coronavirus. M...
详细信息
In this paper, the model reference adaptive control (MRAC) method along with a state feedback controller is employed for synchronizing NFSCV, a complex nonlinear fractional-order stochastic model of the coronavirus. MRAC is a methodology that combines both linear feedback controllers and adaptive law techniques for designing a simple but robust adaptive feedback system. We have added a stochastic noise term to the coronavirus model representing sudden mutations and external disturbances. Also, we will implement the realization of fractional-order differential equations, and it gives us a real representation of the virus. In this paper, we address the question of when the controlled model 'infective or slave system' states can be observed and tuned to the master or referencemodel 'healthy and vaccination' states for our objective functions attempting a minimization between tracking errors of the states of master and slave systems, variance, and squared error integrals. In this paper, we further show that the system is asymptotically stable using the stochastic analysis along with Lyapunov theory. Through these simulations, we are able to see that by using our control algorithm, the infected individuals can be driven to follow a trajectory close to the one followed by the vaccinated individuals.
In this work, the simulation of the behavior of an MRAC assisted solar tracker in solar trajectory tracking tasks has been developed fora prototype of a two-axis solar tracker that presents structural and performance ...
详细信息
In this work, the simulation of the behavior of an MRAC assisted solar tracker in solar trajectory tracking tasks has been developed fora prototype of a two-axis solar tracker that presents structural and performance characteristics capable of supporting PV, CPV, and HCPV-type technology. The proposal is numerically validated by developing an experimental methodology consisting of two stages. The first stage is associated with developing tests of the MRAC-assisted solar tracker to reproduce a solar trajectory (obtained offline by a numerical method) with and without the injection of disturbances (with dynamics equivalent to wind loads in reality), respectively. On the other hand, in the second stage, after replicating the conditions of the tests of stage one but with the assistance of a simple PID type controller, the analysis and comparison of the performance of each alternative is carried out, the above, in terms of tracking error or pointing accuracy. The results show that both alternatives are functional in the development of tests under favorable conditions. However, under conditions with disturbances, it can be noted that the MRAC reduces the tracking error by around 87% compared to PID control.
State and input constraints are ubiquitous in all engineering systems and developing adaptivecontrollers for uncertain linear systems under pre-specified state and input constraints is a problem of fundamental intere...
详细信息
State and input constraints are ubiquitous in all engineering systems and developing adaptivecontrollers for uncertain linear systems under pre-specified state and input constraints is a problem of fundamental interest. For uncertain linear systems, a computationally inexpensive control method is the model reference adaptive control (MRAC). Although MRAC controllers come with strong stability guarantees they do not guarantee system operation within the pre-defined state and input constraints. Several modifications of the MRAC framework have been proposed to address input constraints in uncertain linear systems. Considering the infeasibility of arbitrary reference trajectories, reference modification has been implemented in the case of input constraints in the literature. The resulting conditions on the reference and input signals are difficult to verify online. Similar results on state and input constraints together have also been proposed, albeit resulting in more complex and unverifiable conditions on the control. In this paper, we have developed a modified MRAC controller that can handle state and input constraints in uncertain linear systems. We have also provided easily verifiable conditions on the control and reference under which our stability results hold. Obtaining such a verifiable condition is crucial in practical implementations on safety-critical systems. A combination of reference modification and barrier Lyapunov methods in adaptivecontrol are employed to arrive at these results.
The control of raceway photobioreactors for microalgae production represents a significant challenge due to its non-linear dynamics, the presence of disturbances, the biological nature of the system and the high inter...
详细信息
In this paper, we explore the capabilities of model reference adaptive controllers for better response to uncertain over-actuated nonlinear dynamical systems that use nonlinear refer ence models. It is common practice...
详细信息
In this paper, the high-precision test mass suspension control of the space inertia sensor is investigated by proposing an enhanced output tracking self-triggered model reference adaptive control (MRAC) scheme. Based ...
详细信息
In this paper, the high-precision test mass suspension control of the space inertia sensor is investigated by proposing an enhanced output tracking self-triggered model reference adaptive control (MRAC) scheme. Based on the proposed control scheme, the test masses are adaptively suspended by using reduced-ordered output. To suppress the disturbance due to the test mass suspension, we introduce a sigma-modification approach to the adaptivecontroller with a bounded switching gain. Furthermore, to reduce the actuation consumption, a self-triggering mechanism (STM) is applied to determine the triggering instants using the current responses. An extended Lyapunov analysis based on Filippov solutions proves the boundedness of all closed-loop signals for the suspension system with switching adaptive gains. Numerical simulations are performed to verify the reduction of the actuation cost and the effectiveness of the proposed control scheme, under external disturbances, parameter uncertainties, input saturation, and hysteresis.
In this paper, the H-infinity modelreferenceadaptive problem of a class of switched linear systems with parameter uncertainty under the switching of dwell time is studied. First, in the absence of interference, a ti...
详细信息
In this paper, the H-infinity modelreferenceadaptive problem of a class of switched linear systems with parameter uncertainty under the switching of dwell time is studied. First, in the absence of interference, a time-varying Lyapunov function with increasing coefficient is introduced to derive sufficient conditions for the referenceadaptivecontrol of the H-infinity model, where the dwell time is an arbitrary preset constant. Secondly, an adaptivecontroller and adaptive law are proposed to ensure the asymptotic tracking of the switched system. Then, in the case of interference, the sufficient conditions for the solvable H-infinity modelreferenceadaptive tracking control under dwell time switching are proposed, and the standard L-2-gain performance of the switching system is analysed. The characteristic of this paper is to solve the H-infinity modelreferenceadaptive tracking control problem of a class of switched systems with uncertain parameters by using time-varying Lyapunov function with increasing coefficient. The increasing coefficient in Lyapunov function can increase the degree of freedom of controller design and improve the control performance of the system. Dwell time switching can avoid the H-infinity control problem of switched system which cannot realise state-dependent switching because all state information cannot be obtained.
In this article, we examine the model reference adaptive control problem when the commonly used projection algorithm is utilized, subject to several common assumptions on the set of admissible parameters, in particula...
详细信息
In this article, we examine the model reference adaptive control problem when the commonly used projection algorithm is utilized, subject to several common assumptions on the set of admissible parameters, in particular a compactness constraint as well as knowledge of the sign of the high-frequency gain. It is proven in the literature that for this setup, the closed-loop system is bounded-input bounded-state;since the closed-loop system is not linear time-invariant, this does not imply a bounded gain. Here, we prove a much crisper and detailed bound on the closed-loop behavior consisting of three terms: a decaying exponential on the initial condition, a linear-like convolution bound on the exogenous inputs, and a constant scaled by the square root of the constant in the denominator of the estimator update law;we also provide an upper bound on the two-norm of the tracking error. We then demonstrate that the same kind of bounds hold in the presence of a degree of unmodeled dynamics and plant parameter time-variation.
This article proposes a consensus control approach for the inner-formation system (IFS) containing the drag-free spacecraft and two cubic test masses. Considering the control problem caused by immeasurable states of t...
详细信息
This article proposes a consensus control approach for the inner-formation system (IFS) containing the drag-free spacecraft and two cubic test masses. Considering the control problem caused by immeasurable states of the velocities in the system, a partial-state feedback control scheme is investigated, and the consensus modelreferencemodel reference adaptive control (MRAC) is established to adaptively actuate the IFS to a stable referencemodel in consideration of parameter uncertainties. Concerning the nonaffine electrostatic actuation and suspension of the test masses, the fuzzy logic system is used to estimate the unknown nonlinearities. By combining the fuzzy logic-based estimator and adaptive consensus controller, the partial-state feedback modelreferenceadaptive consensus control scheme is developed for the nonaffine IFS. Theoretical analysis proves the uniformly ultimately boundedness of each closed-loop signal in the formation system, the control performance is verified by the numerical simulations of the drag-free spacecraft IFS.
This article introduces native space embedding for robust adaptivecontrol of ordinary differential equations that contain vector-valued functional uncertainties in a reproducing kernel Hilbert space (RKHS). The propo...
详细信息
This article introduces native space embedding for robust adaptivecontrol of ordinary differential equations that contain vector-valued functional uncertainties in a reproducing kernel Hilbert space (RKHS). The proposed approach is based on a two-phase method for analyzing and designing adaptivecontrollers. In the first phase, a limiting distributed parameter system (DPS), which describes the ideal closed-loop system's performance, is introduced. The limiting DPS is not realizable in practice since it evolves in a generally infinite-dimensional space. In the second phase, consistent finite-dimensional approximations of the DPS are introduced to determine realizable controllers. Uniform ultimate bounds on the trajectory tracking error dynamics are derived for the functional uncertainty classes contained in the native space. These bounds are derived in terms of the power function of the RKHS or in terms of the fill distance of centers that define the scattered basis for approximations. Two numerical examples demonstrate the applicability of the proposed results.
暂无评论