A second-order sliding-mode (SOSM) control method is developed for the regulation problem of a dc-dc buck converter. By taking into account model uncertainties and external disturbances in mathematical model, sliding variable with relative degree 2 first constructed. Then, new SOSM controller such that output voltage will well track desired reference voltage. Theoretical analysis shows resulting closed-loop system globally finite-time stable, while similar results only give proof...

This article investigates the adaptive fuzzy tracking control design for uncertain nonstrict-feedback nonlinear systems with time-varying constraints and asymmetric input saturations. It is known that output constraint, error constraints, saturations are commonly seen issues in many practical engineering due to inherent physical limitations performance requirements. To deal these problems improve convergence rate of system, a novel fixed-time convergent scheme proposed considered via barrier...

This paper presents a novel fixed-time sliding mode disturbance observer (SMDO)-based robust backstepping cruise tracking control scheme with closed-loop finite-time convergence for flexible air-breathing hypersonic vehicles (FAHVs). In order to enhance the system's robustness, SMDO is designed compensate flexibility effects, model uncertainties, and external disturbances in FAHVs. consequence, fixed time of observation achieved independently initial estimation errors. Furthermore, velocity...

Uncertainty and measurement noise are main obstacles that limit the tracking control performances of flexible air-breathing hypersonic vehicles (FAHVs). In this article, we propose a novel fixed-time convergent nonsmooth backstepping scheme for FAHV via augmented sliding mode observers (ASMOs) to overcome these obstacles. The ASMOs first designed dynamics by employing measured states corrupted noises as inputs. On one hand, can simultaneously estimate uncertainties filter out noises. other...

This paper investigates the anti-disturbance control design for flexible air-breathing hypersonic vehicles (FAHVs) with appointed-time prescribed tracking performances. The challenging issues include multisource disturbances, cross-coupling effects of vehicle dynamics, and asymmetric amplitude rate saturations. To address these issues, we propose an performance scheme FAHVs via conditional disturbance negation technique. In contrast to existing rejection approaches, proposed not only...

Strong robustness and smooth speed are two crucial goals of the high-performance permanent magnet synchronous motor (PMSM) drive systems. Conventional active disturbance rejection control (ADRC) strategy generally increases bandwidth extended state observer (ESO) to improve unsatisfactory ability, which will inevitably amplify measurement noise. To address this tough issue, a nonlinear (NESO) using finite-time technique is constructed in article enhance anti-disturbance property. On basis,...

Disturbances of the permanent magnet synchronous motor (PMSM) drive system are usually observed and fully compensated to improve robustness in existing two-degrees-of-freedom control schemes. However, these schemes neglect potential advantages disturbances that have not been well investigated yet. To this end, article proposes a new adaptive conditional disturbance negation (ACDN)-based scheme for PMSM enhance performance by exploiting disturbances. The proposed can utilize advantageous...

It is commonly believed that uncertainties are obstacles to the tracking performances of flexible air-breathing hypersonic vehicles (FAHVs). In addition, estimation unmeasured states in an FAHV makes this issue much more complicated. To deal with these difficulties, article explores a novel adaptive fuzzy nonsmooth backstepping output-feedback control scheme for closed-loop finite-time convergence. First, approximate unknown dynamics FAHV, some function approximators constructed by utilizing...

In this article, an extended state observer (ESO)-based controller with a model predictive governor is designed for 3-D trajectory tracking of underactuated underwater vehicles. The proposed control scheme takes three primary challenges including property, velocity constraint, and lumped disturbance into consideration. With respect to the governor, kinematic error utilized produce reference velocities. Meanwhile, heading angle compensation mechanism avoid steady errors resulting from...

This article presents a new command-filtered composite adaptive neural control scheme for uncertain nonlinear systems. Compared with existing works, this approach focuses on achieving finite-time convergent the higher-order system unknown nonlinearities, parameter uncertainties, and external disturbances. First, radial basis function networks (NNs) are utilized to approximate functions of considered system. By constructing prediction errors from serial-parallel nonsmooth estimation models,...

In this paper, the path-tracking control strategies are proposed for autonomous agricultural vehicles with unknown matched-mismatched disturbances. First of all, a second-order disturbance observer (DOB) is designed to estimate matched and mismatched disturbances mitigate their negative effects. Secondly, by introducing modified sliding mode surface, DOB-based first-order (FOSM) scheme effectively deal system lumped disturbance. To completely eliminate chattering problem existing in FOSM...

This article presents a modified supertwisting sliding mode (STSM) approach for path tracking control of unmanned agricultural tractors in unstructured environments. To address the challenges posed by external disturbances or uncertainties model parameters, disturbance observer is employed to estimate lumped on (SM) dynamics. Furthermore, nonsmooth term introduced replace discontinuous signum function used traditional STSM. By incorporating feedforward compensation and feedback, composite...

With respect to the accurate tracking control for autonomous underwater vehicles (AUVs), this article proposes a novel architecture consisting of piecewise compensation model predictive governor and conditional disturbance negation-based active rejection controller. The designed mechanism is implemented eliminate steady errors resulting from underactuation problem AUVs, aims generate reference velocities satisfying constraints. Concurrently, finite-time extended state observer improve...

Intelligent control is a crucial technology for realizing Industry 5.0, which makes industrial engineering systems more efficient, robust, and resilient. It noteworthy that uncertainties disturbances will inevitably be detrimental to the performances of 5.0 applications. To deal with these issues, we propose novel super-twisting-like continuous extended state observer-based fixed-time composite learning fuzzy scheme apply it typical system. Unlike conventional adaptive methods update...

The tremendous impact of large models represented by ChatGPT [1]–[3] makes it necessary to consider the practical applications such [4]. However, for an artificial intelligence (AI) truly evolve, needs possess a physical "body" transition from virtual world real and evolve through interaction with environments. In this context, "embodied intelligence" has sparked new wave research technology, leading AI beyond digital realm into paradigm that can actively act perceive in environment tangible...

With respect to the dynamic target tracking issue in obstacle environment, this article provides a collision-free framework combining modified guidance vector field (GVF) and disturbance rejection controller. More specifically, two primary improvements are implemented compared with existing GVF methods. The first improvement involves designing variable property deforming elliptic integral curves straight lines pointing point, which prevents robot from detouring. other is construct an...

This study is concerned with the augmented fixed‐time observer based adaptive super‐twisting cruise control for flexible air‐breathing hypersonic vehicles (FAHVs). First, input–output linearisation technique employed to derive a oriented FAHV dynamic model. Then, controller designed track reference velocity and altitude commands when faced various uncertainties disturbances. In addition, novel gain adaptation law constructed as supplement of avoid overestimating values gains. The keeps gains...

Owing to the satisfactory disturbance estimation and compensation capacity, active rejection control (ADRC) is promising for permanent magnet synchronous motor (PMSM) speed regulation system. Unfortunately, performance of ADRC strategy generally affected by measurement noise introduced position sensors. To address this tough issue, an augmented nonlinear extended state observer (ANESO) constructed in paper directly estimate speed. The bode diagrams ANESO-based suppression approach acquired...

Collective behavior of multi-agent systems brings some new problems in control theory and application. Especially, flocking problem with uncertain nonlinear dynamics unknown external disturbances is a challenging problem. Some existing works assume that the intrinsic virtual leader same as those agents, which unreasonable impractical. To solve this issue, we consider an adaptive paper, where allowed to be different from agents. Firstly, approximate each agent, neural network used, whose...

It is commonly believed that observer-based compensation an effective way for disturbance rejection. A less talked about fact such rejection control technique may also degrade performance. In this article, we present a typical cross-coupling system to reveal problem and, more importantly, propose new design principle of conditional negation (CDN) eliminate its potential drawbacks compensation. Qualitative analysis first given general form systems, indicating the necessity CDN. The and CDN...