scholarly journals Fractional-Order Finite-Time, Fault-Tolerant Control of Nonlinear Hydraulic-Turbine-Governing Systems with an Actuator Fault

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3812
Author(s):  
Ying Yang ◽  
Bin Wang ◽  
Yuqiang Tian ◽  
Peng Chen
Keyword(s):  
Power Systems ◽  
Power System ◽  
Fractional Order ◽  
Finite Time ◽  
Control Method ◽  
Fault Tolerant ◽  
External Disturbance ◽  
Fault Tolerant Control ◽  
Hydraulic Turbine ◽  
Actuator Fault

Hydropower units undertake tasks such as peak shaving, frequency modulation, and providing accident reserves in the power system. With the increasing capacity and structural complexity of power systems, hydropower units have become more important. Hydraulic-turbine-governing systems (HTGSs) need to have higher control performance and automation levels to meet the higher regulatory requirements of the power system. To achieve high-quality control, we proposed a new finite-time, fault-tolerant control method for HTGSs with an actuator fault. First, a fractional-order model for HTGSs with uncertainty, external disturbance, and an actuator fault was introduced. Second, a fault estimator that could quickly track the fault signal for an actuator fault was proposed. Then, based on the fractional-order finite-time stability theorem, a finite-time, fault-tolerant controller was proposed for the stabilization of an HTGS. Furthermore, a controller was developed as a fractional differential form combined with a smooth bounded arctangent function to effectively suppress jitters and uncertainties. Finally, numerical experimental results verified the validity and robustness of the proposed scheme.

scholarly journals Robust Adaptive Sliding Mode Fault Tolerant Control for Nonlinear System with Actuator Fault and External Disturbance

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Liang Zheng ◽  
Xuelian Dong ◽  
Qian Luo ◽  
Menglan Zeng ◽  
Xinping Yang ◽  
...  
Keyword(s):  
Control Method ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
External Disturbance ◽  
Fault Tolerant Control ◽  
Actuator Fault ◽  
Estimation Errors ◽  
Adaptive Sliding Mode ◽  
Sliding Motion ◽  
Robust Adaptive

In this paper, an adaptive sliding mode fault tolerant control (ASMFTC) approach is proposed for a class of nonlinear systems with actuator fault, uncertainty, and external disturbance. Specifically, first, a novel observer is proposed to estimate the state, actuator fault, and external disturbance. Then, by utilising the observed information, a novel output sliding mode observer is constructed. In the control method, an adaptive law and two compensators are designed to attenuate the unknown estimation errors, actuator fault, and disturbance. Furthermore, the reaching ability of the sliding motion is analysed and the H-infinite performance is introduced to ensure the robustness of the system. Finally, a flexible single joint manipulator system and a two-cart system are used to verify the effectiveness of the proposed method.

Fixed-time fractional-order sliding mode control for nonlinear power systems

2020 ◽  
Vol 26 (17-18) ◽  
pp. 1425-1434 ◽  
Author(s):  
Sunhua Huang ◽  
Jie Wang
Keyword(s):  
Sliding Mode Control ◽  
Power System ◽  
Fractional Order ◽  
Finite Time ◽  
Control Method ◽  
Sliding Mode ◽  
Fixed Time ◽  
Sliding Mode Controller ◽  
Mode Control ◽  
Time Control

In this study, a fractional-order sliding mode controller is effectively proposed to stabilize a nonlinear power system in a fixed time. State trajectories of a nonlinear power system show nonlinear behaviors on the angle and frequency of the generator, phase angle, and magnitude of the load voltage, which would seriously affect the safe and stable operation of the power grid. Therefore, fractional calculus is applied to design a fractional-order sliding mode controller which can effectively suppress the inherent chattering phenomenon in sliding mode control to make the nonlinear power system converge to the equilibrium point in a fixed time based on the fixed-time stability theory. Compared with the finite-time control method, the convergence time of the proposed fixed-time fractional-order sliding mode controller is not dependent on the initial conditions and can be exactly evaluated, thus overcoming the shortcomings of the finite-time control method. Finally, superior performances of the fractional-order sliding mode controller are effectively verified by comparing with the existing finite-time control methods and integral order sliding mode control through numerical simulations.

Adaptive Fractional-Order Fault-Tolerant Tracking Control for UAV Based on High-Gain Observer

2017 ◽  
Author(s):  
Ziquan Yu ◽  
Youmin Zhang ◽  
Yaohong Qu ◽  
Zhewen Xing
Keyword(s):  
Fractional Order ◽  
Tracking Control ◽  
Fault Tolerant ◽  
External Disturbance ◽  
Tracking Error ◽  
Small Region ◽  
High Gain ◽  
Actuator Fault ◽  
High Gain Observer ◽  
Flight Path Angle

This paper is concerned with the fractional-order fault-tolerant tracking control design for unmanned aerial vehicle (UAV) in the presence of external disturbance and actuator fault. Based on the functional decomposition, the dynamics of UAV is divided into velocity subsystem and altitude subsystem. Altitude, flight path angle, pitch angle and pitch rate are involved in the altitude subsystem. By using an adaptive mechanism, the fractional derivative of uncertainty including external disturbance and actuator fault is estimated. Moreover, in order to eliminate the problem of explosion of complexity in back-stepping approach, the high-gain observer is utilized to estimate the derivatives of virtual control signal. Furthermore, by using a fractional-order sliding surface involved with pitch dynamics, an adaptive fractional-order fault-tolerant control scheme is proposed for UAV. It is proved that all signals of the closed-loop system are bounded and the tracking error can converge to a small region containing zero via the Lyapunov analysis. Simulation results show that the proposed controller could achieve good tracking performance in the presence of actuator fault and external disturbance.

scholarly journals Decentralized Fault Detection and Fault-Tolerant Control for Nonlinear Interconnected Systems

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 591
Author(s):  
Shun Zhou ◽  
Jianjun Bai ◽  
Feng Wu
Keyword(s):  
Fault Detection ◽  
Information Exchange ◽  
Control Method ◽  
Communication Protocol ◽  
Fault Tolerant ◽  
External Disturbance ◽  
Detection Threshold ◽  
Fault Tolerant Control ◽  
Interconnected System ◽  
Detection Scheme

The nonlinear interconnected system is a complex and important system in daily production and life in general. Due to the interconnection influence between subsystems and external disturbance factors, the system is prone to failure. For this kind of system, a decentralized fault detection and fault tolerant control method is proposed here. Compared with the traditional control scheme, this paper designs a subsystem communication protocol to reduce the information exchange between subsystems. Based on this communication protocol, a fault detection scheme is then designed. Due to the existence of a fault detection threshold in this scheme, the system can detect the fault in time without missing it or having a false alarm. Under the assumed condition, the adaptive control rate is obtained by establishing the adaptive approximation model to approximate the upper bound of the fault, and the subsystem adaptively adjusts the control rate according to the fault condition, so that the system can quickly recover to stability. Finally, a simulation program is used to verify the proposed method.

Adaptive anti-saturation fault-tolerant control of hypersonic vehicle with actuator faults

2018 ◽  
Vol 233 (6) ◽  
pp. 2066-2083
Author(s):  
Jing-guang Sun ◽  
Shen-Min Song ◽  
Peng-Li ◽  
Guan-qun Wu
Keyword(s):  
Finite Time ◽  
Control Method ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Input Saturation ◽  
Reference Signal ◽  
Fault Tolerant Control ◽  
Hypersonic Vehicle ◽  
Actuator Faults ◽  
The Impact

In this paper, related researches and analyses are conducted for the tracking problem of the hypersonic vehicle subject to external disturbances, actuator faults, and input saturation. Firstly, to achieve automatic adjustment of control gains and deal with the impact of dynamic failures of system without requiring prior knowledge of the fault, a new modified fast nonsingular terminal sliding manifold is proposed, and a fast adaptive finite time fault-tolerant controller is provided combining the adaptive control method and terminal sliding mode. Then, a fast adaptive finite time anti-saturation fault-tolerant controller is presented to further solve the problem of input saturation, under which both of the velocity and altitude can track respective reference signal with the actuator input constraint. Finally, the closed-loop stability under the proposed two adaptive fault-tolerant control schemes is analyzed, and numerical simulations of longitudinal model of the hypersonic vehicle are demonstrated to further confirm the effectiveness of the proposed approach.

Neural Adaptive Fault Tolerant Control of Nonlinear Fractional Order Systems Via Terminal Sliding Mode Approach

2019 ◽  
Vol 14 (3) ◽  
Author(s):  
Bijan Hashtarkhani ◽  
Mohammad Javad Khosrowjerdi
Keyword(s):  
Fractional Order ◽  
Finite Time ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Fault Tolerant Control ◽  
State Feedback Control ◽  
Time Stability ◽  
Terminal Sliding Mode ◽  
Finite Time Stability ◽  
Output Tracking

This article proposes an adaptive neural output tracking control scheme for a class of nonlinear fractional order (FO) systems in the presence of unknown actuator faults. By means of backstepping terminal sliding mode (SM) control technique, an adaptive fractional state-feedback control law is extracted to achieve finite time stability along with output tracking for an uncertain faulty FO system. The unknown nonlinear terms are approximated by radial-basis function neural network (RBFNN) with unknown approximation error upper bound. Using convergence in finite time and fractional Lyapunov stability theorems, the finite time stability and tracking achievement are proved. Finally, the proposed fault tolerant control (FTC) approach is validated with numerical simulations on two fractional models including fractional Genesio–Tesi and fractional Duffing's oscillator systems.

Neural network-based adaptive fault tolerant tracking control for unmanned autonomous helicopters with prescribed performance

2019 ◽  
Vol 233 (12) ◽  
pp. 4350-4362 ◽  
Author(s):  
Kun Yan ◽  
Mou Chen ◽  
Qingxian Wu
Keyword(s):  
Fault Tolerant ◽  
External Disturbance ◽  
Tracking Error ◽  
Fault Tolerant Control ◽  
Actuator Fault ◽  
Error Performance ◽  
System Uncertainty ◽  
Prescribed Performance ◽  
Medium Scale ◽  
Autonomous Helicopter

In this paper, the issue of prescribed performance-based fault tolerant control is investigated for the medium-scale unmanned autonomous helicopter with external disturbance, system uncertainty and actuator fault. The altitude and attitude combination unmanned autonomous helicopter model is established. An error transformation function is proposed to guarantee that the tracking error satisfies the prescribed performance. The parameter adaptation method is adopted to handle the external unknown disturbance and the radial basis function neural networks are employed to approximate the interaction functions including the system uncertainty. The auxiliary system is introduced to weaken the effect of actuator fault, which can effectively avoid the singularity. Based on the backstepping control technology, an adaptive neural fault tolerant control scheme is developed to ensure the boundness of all closed-loop system signals and the specified tracking error performance. Simulation studies on the medium-scale unmanned autonomous helicopter are performed to demonstrate the efficiency of the designed control strategy.

scholarly journals Adaptive Finite-Time Command Filtered Fault-Tolerant Control for Uncertain Spacecraft with Prescribed Performance

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Zhongtian Chen ◽  
Qiang Chen ◽  
Xiongxiong He ◽  
Mingxuan Sun
Keyword(s):  
Finite Time ◽  
Controller Design ◽  
Actuator Saturation ◽  
Fault Tolerant ◽  
External Disturbance ◽  
Fault Tolerant Control ◽  
Prescribed Performance ◽  
Attitude Stabilization ◽  
Virtual Control ◽  
System Output

In this paper, an adaptive finite-time fault-tolerant control scheme is proposed for the attitude stabilization of rigid spacecrafts. A first-order command filter is presented at the second step of the backstepping design to approximate the derivative of the virtual control, such that the singularity problem caused by the differentiation of the virtual control is avoided. Then, an adaptive fuzzy finite-time backstepping controller is developed to achieve the finite-time attitude stabilization subject to inertia uncertainty, external disturbance, actuator saturation, and faults. Through using an error transformation, the prescribed performance boundary is incorporated into the controller design to guarantee the prescribed performance of the system output. Numerical simulations demonstrate the effectiveness of the proposed scheme.

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