This study presents the development of a methodology for designing neuro-adaptive robust controllers based on a referencemodel associated with an artificial neural network of radial basis functions (ANN-RBF) for soli...
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This study presents the development of a methodology for designing neuro-adaptive robust controllers based on a referencemodel associated with an artificial neural network of radial basis functions (ANN-RBF) for solid fuel suborbital rockets. The modelling and neuro-adaptive robust control algorithms for these rockets are presented. Initially, the methodology is evaluated for a robust controller based on a referencemodel with ANN-RBF for altitude control. The main objective of the control is to suppress the effect of non-linear uncertainties inherent in the process. The method involves mathematical and computational modelling, together with the design of adaptivecontrollers for stability and performance analysis. The controllers considered include model reference adaptive control (MRAC) techniques and a modelreference neuro-adaptivecontrol (MRNAC) approach. The analysis, carried out using computer simulations, evaluates the behavior of each controller in relation to system stability and performance. The final objective is to select the most suitable controller for the suborbital rocket, taking into account the system constraints, robust performance requirements, robust stability, and optimal adaptability. This research promotes the development of adaptivecontrollers for suborbital rockets, with possible applications in scientific research and commercial launches.
This paper introduces a sensorless speed and position control for a permanent magnet synchronous motor (PMSM) drive designed for light electric vehicles (LEVs). This approach utilizes a modelreferenceadaptive contro...
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This paper introduces a sensorless speed and position control for a permanent magnet synchronous motor (PMSM) drive designed for light electric vehicles (LEVs). This approach utilizes a model reference adaptive control (MRAC) strategy, featuring novel flux and torque error based MRAC with an enhanced voltage model. Notably, this method does not rely on speed error and eliminates need for derivative terms in estimation process. Presented sensorless estimation method reduces effect of load variation in estimation as well as improves response from low to high speed. Moreover, to enhance speed controller working, an adaptive improved sliding mode controller (ISMC) is adopted, which adapts changes in terms of finite time convergence as well as accurate tracking and reduced chattering. To achieve fast convergence in finite time, fast integral terminal sliding surface along with novel reaching law is selected for sliding mode controller design. Furthermore, a simple predictive current controller is utilized, which eliminates need of a modulator and incorporates inverter nonlinearities. Simulation implementation of control is executed in Simulink and its experimental performance is verified on a laboratory test setup. A comparative analysis of PI controller with improved SMC and sensorless position estimation by improved flux MRAC with conventional MRAC is done.
In this paper, an equivalent multi-body dynamics model of high-speed train with uncertain parameter is established. Based on this detailed model and neural network minimum parameter learning algorithm, an adaptive sli...
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In this paper, an equivalent multi-body dynamics model of high-speed train with uncertain parameter is established. Based on this detailed model and neural network minimum parameter learning algorithm, an adaptive sliding mode control method is designed for speed and position tracking control of high-speed train, and the stability of the proposed control method is proved strictly. Then an adaptive fuzzy sliding mode control method (AFSMC) is presented to avoid chattering caused by excessive robust switching gain. Finally, numerical tests are carried out on the proposed AFSMC under different scenarios and operation strategies, and model reference adaptive control (MRAC), PID control and sliding mode control are also tested under the same condition for performance comparison. The results show that the proposed control method is superior to the currently used method. More specifically, compared with MRAC and PID, the average speed tracking accuracy of AFSMC is improved by 0.25 km/h and 0.18 km/h, and the average position tracking accuracy is improved by 0.68 m and 0.7 m, respectively.
A distributed adaptivecontrol is proposed for H-infinity tracking of an interconnected dynamical system in the presence of L-2 disturbances and system/interconnection uncertainties. A referencemodel which achieves a...
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A distributed adaptivecontrol is proposed for H-infinity tracking of an interconnected dynamical system in the presence of L-2 disturbances and system/interconnection uncertainties. A referencemodel which achieves a robust tracking against L-2 disturbances is introduced by using H-infinity control with transients. Then a distributed adaptivecontrol law is developed for an uncertain interconnected dynamical system, where it employs the specified referencemodel. It is shown that the boundedness of the error dynamics behaviors as well as zero tracking error in the steady state is guaranteed by the proposed distributed adaptivecontrol in the presence of disturbances and uncertainties. An explicit error bound related to H-infinity tracking is also established.
Due to high efficiency operation capability and no special site requirement for landing and taking off, plant protection unmanned aerial vehicle (UAV) has been widely used in precision agriculture. However, there are ...
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Due to high efficiency operation capability and no special site requirement for landing and taking off, plant protection unmanned aerial vehicle (UAV) has been widely used in precision agriculture. However, there are also some factors affecting flight operation safety, such as partial failure of actuator and uncertainty caused by change of the mass with time, which mainly lead to altitude and attitude control failure problem. In view of the operation characteristics of the spray tank and actuator with partial failure, a hybrid controlmodel of plant protection UAV with actuator failure and uncertainty is established. In order to design control law to improve fault tolerant capability of the flight control system, a fractional-order model reference adaptive control method (FO-MRAC) is proposed. Based on our FO-MRAC algorithm, altitude and attitude control laws of plant protection UAV are devised. Popov hyper-stability theorem is also used to prove the system's stability. Finally, numerical simulation is carried out to verify the effectiveness of our method. Compared with conventional proportional-integral-differential (PID) control and model reference adaptive control (MRAC) methods, our method has advantages in improving the convergence speed, reducing overshoot, and robustness of the system.
This paper summarizes several key issues of importance related to intercept of high-speed maneuvering targets under stratospheric altitude conditions, where it is unlikely that the interceptor will have a significant ...
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This paper summarizes several key issues of importance related to intercept of high-speed maneuvering targets under stratospheric altitude conditions, where it is unlikely that the interceptor will have a significant speed and/or maneuverability advantage. It explains why one cannot rely on traditional proportional navigation guidance and presents simulation results for a recently developed finite time method of guidance. A simplified version of finite time intercept guidance is derived, and a modification required to allow it to be practically implemented is described. Simulation results are presented to illustrate the advantages of the simplified version.
This paper addresses an adaptive rigid-body pose-tracking control problem with unknown system parameters. The proposed control is based on a noncertainty equivalence (NCE) adaptive principle applied to the configurati...
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This paper addresses an adaptive rigid-body pose-tracking control problem with unknown system parameters. The proposed control is based on a noncertainty equivalence (NCE) adaptive principle applied to the configuration manifold of rigid-body motion, i.e., special Euclidean group SE(3), and its tangent bundle TSE(3). The controller drives the system to follow an arbitrary reference trajectory with bounded time derivatives. The system states are composed of the elements of SE(3), consisting of rotations and translations, and the six-dimensional vector of angular and translational velocities in Euclidean space. Almost-global-asymptotic stability of the system is demonstrated using a Morse-Lyapunov stability analysis. Then, the performance of the proposed controller is verified and is compared to the results obtained by a certainty-equivalence (CE) adaptivecontrol applied to exponential coordinates associated with the linear space of the Lie algebra se(3). It is shown that the TSE(3)-based NCE adaptivecontrol design can eliminate the performance degradation due to the cancellation of uncertain parameter effects that would otherwise appear when the CE adaptivecontroller is used. As a result, the proposed NCE-based adaptive pose-tracking controller recovers the closed-loop pose-tracking controller performance with the system parameters fully known to the controller.
The objective of modelreferencecontrol is to design a controller that regulates the system's behavior so as to match a specified referencemodel. This paper investigates necessary and sufficient conditions for m...
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In this article, a predictor-based model reference adaptive control method is proposed for a JetCat SPT5 turboshaft engine in full thrust, cruise, and idle modes. In the predictor-based modelreferenceadaptive contro...
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In this article, a predictor-based model reference adaptive control method is proposed for a JetCat SPT5 turboshaft engine in full thrust, cruise, and idle modes. In the predictor-based model reference adaptive control method, in addition to the tracking error, the predictor error is also utilized in adaptive laws to achieve the desired control objectives, such as improving the tracking performance and control signals, and reducing the tracking error. The proposed method is implemented on a turboshaft engine system with actual dynamic values. First, three properly separated equilibrium points are selected on the nominal plant equilibrium manifold to linearize the plant model at the equilibrium points. Then, the predictor-based model reference adaptive controlcontroller is designed and investigated for the three equilibrium points generating three operating modes of the engine, that is, full thrust, cruise, and idle. The stability of the control system is proved by the Lyapunov method. To evaluate the efficiency of the state predictor method in the simulation scenarios, the proposed method is compared with the classic model reference adaptive control method. The simulation results illustrate the superiority of the predictor-based modelreference method due to the reduction of unwanted fluctuations in tracking performance, faster convergence of the tracking error to zero, and smoother control signals for all the equilibrium points.
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