In this paper, a novel method is proposed for direction of arrival (DOA) estimation in the presence of impulsive noise. By introducing the hyperbolic secant function into the framework, a novel DOA estimator is design...
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In this paper, a novel method is proposed for direction of arrival (DOA) estimation in the presence of impulsive noise. By introducing the hyperbolic secant function into the framework, a novel DOA estimator is designed. Based on the proposed estimator and low-rank decomposition, a robust subspace is obtained through alternative optimization. DOA estimation is achieved by applying the multiple signal classification (MUSIC) algorithm to the derived subspace. A detailed optimization procedure is outlined, and the convergence of the proposed estimator is proven. Comprehensive simulation results demonstrate that the proposed method could achieve superior performance in impulsive noise environments, especially under strongly impulsive conditions.
The indirect field-oriented control system of an induction motor is still coupling and nonlinear. It is not satisfied to control the speed of the induction motor based on field-oriented control using conventional PI c...
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The indirect field-oriented control system of an induction motor is still coupling and nonlinear. It is not satisfied to control the speed of the induction motor based on field-oriented control using conventional PI control. In order to improve the dynamic characteristics of above motor drive, a nonlinear PI type speed controller based on hyperbolic tangent function was presented, and applied in the indirect vector control of an induction motor. According to modal equivalence principle, it is proved that the controller is equivalent to a robust fuzzy logic controller. However, comparing with fuzzy logic control (FLC), the nonlinear controller has some advantages such as simple implementation, no high-frequency quiver. Simulations and experiments results demonstrate good dynamic performance can be achieved based on this nonlinear PI speed controller in the vector control of induction motor.
In this paper, we establish some lower and upper bounds for certain hyperbolic functions in terms of partial sums of their Taylor series. These allow us to present two completely monotonic functions involving gamma fu...
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In this paper, we establish some lower and upper bounds for certain hyperbolic functions in terms of partial sums of their Taylor series. These allow us to present two completely monotonic functions involving gamma function. As consequences, sharp Burnside type approximations for gamma function, sharp Detemple-Wang type approximations for psi function, and sharp bounds for polygamma functions are deduced, which generalize and improve some known results. (c) 2016 Elsevier Inc. All rights reserved.
The Smith's approximation formula for the gamma function is given by Gamma(x+1/2)=root 2 pi(x/e)(x) (2xtanh 1/2x)(x/2) (1 +O (1/x(5))), as x -> infinity. In this paper, by means of a little known power series, ...
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The Smith's approximation formula for the gamma function is given by Gamma(x+1/2)=root 2 pi(x/e)(x) (2xtanh 1/2x)(x/2) (1 +O (1/x(5))), as x -> infinity. In this paper, by means of a little known power series, we develop this formula to an asymptotic expansions: Gamma(x+1/2)/root 2 pi(x/e)(x) similar to(2x tanh1/2x)(x/2) exp (Sigma(n=3) [(2n)!-(2n-1)2(2n-1)](1-2(1-2n))/2n(2n-1)(2n)!) B-2n/x(2n-1));as x -> infinity, and give an estimate of remainder in the above asymptotic series, where B2, is the Bernoulli number. Moreover, as relevant results, *** type asymptotic expansions for the gamma function F (x 1/2) are obtained;an asymptotic expansion for Wallis ratio and an estimate of the remainder are established. (C) 2019 Elsevier Inc. All rights reserved.
This article presents an optimal tracking controller retrofitted with a nonlinear adaptive integral compensator, specifically designed to ensure robust and accurate positioning of Vertical Take-Off and Landing (VTOL) ...
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This article presents an optimal tracking controller retrofitted with a nonlinear adaptive integral compensator, specifically designed to ensure robust and accurate positioning of Vertical Take-Off and Landing (VTOL) Unmanned Aerial Vehicles (UAVs) that utilize contra-rotating motorized propellers for differential thrust generation. The baseline position controller is synthesized by employing a fixed-gain Linear Quadratic Integral (LQI) tracking controller that stabilizes position by tracking both state variations and pitch-axis tracking error integral, which adjusts the voltage to control each coaxial propeller's speed accurately. Additionally, the baseline tracking control law is supplemented with a rate-varying integral compensator. It operates as a nonlinear scaling function of the tracking-error velocity and the braking acceleration to enhance the accuracy of reference tracking without sacrificing its robustness against exogenous disruptions. The controller's performance is analyzed by performing experiments on a tailored hardware-in-the-loop aero-pendulum testbed, which is representative of VTOL UAV dynamics. Experimental results demonstrate significant improvements over the nominal LQI tracking controller, achieving 17.9%, 61.6%, 83.4%, 43.7%, 35.8%, and 6.8% enhancement in root mean squared error, settling time, overshoot during start-up, overshoot under impulsive disturbance, disturbance recovery time, and control energy expenditure, respectively, underscoring the controller's effectiveness for potential UAV and drone applications under exogenous disturbances.
In this research, an LMI-based global sliding mode controller law with a novel switching function for the sliding surface using hyperbolic functions is presented and is used for stabilization and robustness of three-d...
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ISBN:
(纸本)9781728115085
In this research, an LMI-based global sliding mode controller law with a novel switching function for the sliding surface using hyperbolic functions is presented and is used for stabilization and robustness of three-dimensional nonlinear systems with uncertainty. The asymptotic stability of the system's state variables is guaranteed by Linear Matrix Inequality (LMI) and furthermore, considering the uncertainty and nonlinear terms, the reaching phase of the sliding surface is deleted. Finally, the proposed control technique is implemented on Genesio-Tesi chaotic system and the results of the simulation are analyzed.
In the article, we establish several Lazarević and Cusa type inequalities involving the hyperbolic sine and cosine functions with two parameters. As applications, we find some new bounds for certain bivariate means. &...
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At present, most of the researches on the memristor simulators are flux-controlled, there are fewresearches on the charge-controlled memristor simulator, and the hyperbolic function simulator is seldommentioned. There...
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At present, most of the researches on the memristor simulators are flux-controlled, there are fewresearches on the charge-controlled memristor simulator, and the hyperbolic function simulator is seldommentioned. Therefore, a general-purpose simulator of charge-controlled memristor based on hyperbolic functionis proposed. The simulator realizes the conversion between voltage and current signals in the circuit throughthe voltage-current mutual conversion circuit, and calculates the generated signals through the correspondingmodule in the circuit, and finally obtains the universal hyperbolic charge-controlled memristor model. Thesimulator can realize the charge-controlled memristor corresponding to hyperbolic sine, hyperbolic cosine andhyperbolic tangent function. The equivalent circuit of the general-purpose hyperbolic function charge-controlledmemristor simulator is mainly composed of operational amplifier, resistor, capacitor, triode and other basiccomponents. By analyzing the volt-ampere characteristic curves of the simulator at different amplitudes anddifferent frequencies, it is concluded that the simulator conforms to the basic characteristics of memory *** model of hyperbolic charge-controlled memristor presented in this paper has a certain reference significancefor the development of memristor model.
In this paper, by using the residue theorem and asymptotic formulas of trigonometric and hyperbolic functions at the poles, we establish many relations involving two or more infinite series of trigonometric and hyperb...
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In this paper, by using the residue theorem and asymptotic formulas of trigonometric and hyperbolic functions at the poles, we establish many relations involving two or more infinite series of trigonometric and hyperbolic functions. In particular, we evaluate in closed form certain classes of infinite series containing hyperbolic functions, which are related to Gamma functions and power of pi. Moreover, some interesting new consequences and illustrative examples are considered.
We present an integrated mathematical model of vehicle-following control for the establishment, maintenance, and re-establishment of the previous or new safe and efficient steady-following state. The hyperbolic functi...
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We present an integrated mathematical model of vehicle-following control for the establishment, maintenance, and re-establishment of the previous or new safe and efficient steady-following state. The hyperbolic functions are introduced to establish the corresponding mathematical models, which can describe the behavioral adjustment of the following vehicle steered by a well-experienced driver under complex vehicle following situations. According to the proposed mathematical models, the control laws of the following vehicle adjusting its own behavior can be calculated for its moving in safety,efficiency, and smoothness(comfort). Simulation results show that the safe and efficient steady-following state can be well established, maintained, and re-established by its own smooth(comfortable) behavioral adjustment with the synchronous control of the following vehicle’s velocity, acceleration, and the actual following distance.
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