In this article, an adaptive fault-tolerant tracking control algorithm is developed for the multi-input-multi-output (MIMO) pure-feedback nonlinear systems with full state constraints. The state constraints are time-v...
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In this article, an adaptive fault-tolerant tracking control algorithm is developed for the multi-input-multi-output (MIMO) pure-feedback nonlinear systems with full state constraints. The state constraints are time-varying, hence greatly improve the applicability of the result but significantly increase the difficulties and complexities of control system design. To overcome the feasibility conditions in barrier Lyapunov function for handling time-varying constraints, a novel nonlinear mapping method for MIMO nonlinear systems is developed. Adaptive techniques and Neural Networks (NNs) are applied to estimate unknown uncertainties and disturbances, which the tracking control accuracy is improved. It is proved that the designed control algorithm can not only achieve the control objectives but also guarantee the boundedness of all signals. Finally, the effectiveness of the developed control algorithm is demonstrated via a simulation example. Copyright (c) 2024 The Authors.
In this paper, a state feedback controller is designed for a four-phase interleaved dc-dc boost converter connected to PEM fuel cell to regulate the output voltage and current around desired values. The proposed contr...
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In this paper, a state feedback controller is designed for a four-phase interleaved dc-dc boost converter connected to PEM fuel cell to regulate the output voltage and current around desired values. The proposed controller features two loops based on state feedback, transforming the system into a state representation. The synthesis of the controller gains is validated using the Linear Quadratic Regulator (LQR) technique. To demonstrate its effectiveness, a typical proportional-integral (PI) controller based on the same average modelling is designed for further comparison and discussion. The performance metrics, including output voltage, source current ripples, settling time, and overshoot showcase the high robustness and dynamic characteristics of the proposed controller. The simulations are conducted using Matlab Simulink with a 1kW fuel cell system.
Wave energy constitutes a crucial player in the future renewable energy mix. Within this field, model-based optimal control strategies have a fundamental role in minimising the associated levelised energy cost. Model-...
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Wave energy constitutes a crucial player in the future renewable energy mix. Within this field, model-based optimal control strategies have a fundamental role in minimising the associated levelised energy cost. Model-system discrepancies can compromise control performance. In particular, faulty conditions must be accommodated since they can severely affect control efficiency and device integrity. For this purpose, an FDI estimator-based optimal control reconfiguration strategy, capable of restoring optimality with sensor faults, is proposed. The technique is tested under nominal and faulty conditions, in representative operating scenarios, showing a remarkable capability to recover energy absorption performance even under severe measurement mismatches. Copyright (c) 2024 The Authors.
This paper addresses the key question that when faults occur either the aircraft system dynamics changes due to the fault or these dynamics are unknown (precisely). This question is addressed for the important case of...
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This paper addresses the key question that when faults occur either the aircraft system dynamics changes due to the fault or these dynamics are unknown (precisely). This question is addressed for the important case of Air Data Sensor failures, due to e.g. icing, for fixed wing aircraft operating in a nominal flight condition. The solution to this question uses basic ideas from subspace identification to cast this problem in linear least squares problem with convex constraints (nuclear norm and 1-norm constraints). The latter are relaxations of a rank and cardinality *** presented solution is validated using real-life flight test data. Copyright (c) 2024 The Authors.
This paper presents mono camera-based GPS spoofing detection for aerial vehicles utilizing only image information besides the initial orientation of the vehicle. Orientation information is propagated and motion direct...
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This paper presents mono camera-based GPS spoofing detection for aerial vehicles utilizing only image information besides the initial orientation of the vehicle. Orientation information is propagated and motion direction is estimated solely from the mono camera images through the estimation of the essential matrix. Histograms of Oriented Displacements and their correlation are considered to detect spoofing considering GPS and image-based data. Straight and turning simulated flight trajectories of a fixed wing research drone with different turbulence levels are compared to evaluate the method. The results are promising with timely detection of every spoofing scenario and without false alarm. The exploration of real flight data is the topic of future development. Copyright (c) 2024 The Authors.
In this paper, a secure remote monitoring approach is developed based on secret sharing. In order to improve the confidentiality of the signals transmitted over the network, each sensor output signal and each control ...
In this paper, a secure remote monitoring approach is developed based on secret sharing. In order to improve the confidentiality of the signals transmitted over the network, each sensor output signal and each control input signal are split into two shares and sent to two clouds. In each cloud, a partial residual signal is generated based on the received signals. Then the partial residual signals are fused to obtain the residual signal that contains the fault information. The proposed approach protects signals from being leaked, as only partial information is contained in each cloud. The proposed approach is illustrated with an example of the quadruple-tank. Copyright (c) 2024 The Authors. This is an open access article under the CC BY-NC-ND license (https://***/licenses/by-nc-nd/4.0/)
Cyber-physical systems (CPSs) integrate controllers, sensors, actuators, and communication networks. Tight integration with communication networks makes CPSs vulnerable to cyberattacks. In this paper, we investigate t...
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Cyber-physical systems (CPSs) integrate controllers, sensors, actuators, and communication networks. Tight integration with communication networks makes CPSs vulnerable to cyberattacks. In this paper, we investigate the impact of denial of service (DoS) attack on the stability of cyber physical systems by considering the transmission control protocol (TCP) and extract a sufficient stability condition in linear matrix inequality (LMI) form. To this end, we model the TCP-CPS under DoS attack as a switching LPV time-delay system by using the Markov jump model. Then, we design a parameter-dependent stabilizing controller for CPS under DoS attack, by considering the network parameters. Finally, we prove efficiency and the feasibility of our findings through a well-known case study in the networked controlsystems literature. Copyright (C) 2024 The Authors. This is an open access article under the CC BY-NC-ND license (https://***/licenses/by-nc-nd/4.0/)
In this paper, a fault-tolerant funnel-based controller in combination with extended state observer (ESO) for heading control of surface vessels is proposed. Using the proposed scheme, the states and the total disturb...
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In this paper, a fault-tolerant funnel-based controller in combination with extended state observer (ESO) for heading control of surface vessels is proposed. Using the proposed scheme, the states and the total disturbance caused by rudder faults (loss of effectiveness and bias) and environmental forces (low-frequency wave, wind and current) are estimated simultaneously. The proposed method just by measuring the heading angle guarantees predetermined transient and steady-state tracking performances. The explosion of complexity inherent in the backstepping approach has been effectively tackled by employing dynamic surface control (DSC). Based on the Lyapunov synthesis approach, it is proved that all the closed-loop signals are semi-globally uniformly ultimately bounded (SGUUB). Simulation results validate the efficiency of the proposed method in the presence of rudder faults and ocean disturbances. Copyright (c) 2024 The Authors.
This paper aims to present a scenario of an active and hard-to-detect cyber-attack exhibiting high potential for success on industrial communication systems. On the other hand, the paper also proposes appropriate cont...
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This paper aims to present a scenario of an active and hard-to-detect cyber-attack exhibiting high potential for success on industrial communication systems. On the other hand, the paper also proposes appropriate contractions providing enhanced resilience against class of attacks which is the interest of this paper. The attack targets the majority of currently operating industrial fieldbus systems that are using Modbus communication protocol with a physical layer implemented by EIA/TIA-485 specifications. A vulnerability in the specification of the physical layer of the reference model of the Modbus communication protocol was exploited when constructing the attack scenario. To verify this scenario a physical sabotaging device was developed. This device is particularly intended for testing the detectability and isolability of attacks, and thus for evaluating the effectiveness of approaches to detecting and isolating cyber attacks. Selected results of the tests carried out are presented, as well as the recommendations for the practitioners. Copyright (c) 2024 The Authors.
In this paper we present experimental results concerning the impact of the chosen torque control gain on the deterioration of the drive-train in wind turbines. Here the deterioration is considered to be produced by th...
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In this paper we present experimental results concerning the impact of the chosen torque control gain on the deterioration of the drive-train in wind turbines. Here the deterioration is considered to be produced by the mechanical stress, on the drive-train, and it is measured as the dissipated power at this level. The wind turbine is assumed to be controlled, into the variable-speed region, by using the optimal torque control method, commonly used for maximum power tracking. In this work, we present and discuss the obtained results of produced energy and dissipated one (at the drive-train level), for different choices of the torque control gain under the presence of high turbulence intensity of the wind speed. The tests have been performed in simulation by using real wind-speed data and by a combined simulated drive-train and a real mini wind turbine available at GIPSA-lab. Copyright (c) 2024 The Authors.
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