7,852 research outputs found
A survey on fractional order control techniques for unmanned aerial and ground vehicles
In recent years, numerous applications of science and engineering for modeling and control of unmanned aerial vehicles (UAVs) and unmanned ground vehicles (UGVs) systems based on fractional calculus have been realized. The extra fractional order derivative terms allow to optimizing the performance of the systems. The review presented in this paper focuses on the control problems of the UAVs and UGVs that have been addressed by the fractional order techniques over the last decade
An Adaptive Approach to Sensor Bias Fault Diagnosis and Accommodation for a Class of Input-Output Nonlinear Systems
This paper presents an adaptive sensor fault
diagnosis and accommodation scheme for multiple sensor bias
faults for a class of input-output nonlinear systems subject to
modeling uncertainty and measurement noise. The proposed
scheme consists of a nonlinear estimation model that includes
an adaptive component which is initiated upon the detection
of a fault, in order to approximate the magnitude of the
bias faults. A detectability condition characterizing the class of
detectable sensor bias faults is derived and the robustness and
stability properties of the adaptive scheme are presented. The
estimation of the magnitude of the sensor bias faults allows the
identification of the faulty sensors and it is also used for fault
accommodation purposes. The effectiveness of the proposed
scheme is demonstrated through a simulation example
Neural Back-Stepping Control of Hypersonic Flight Vehicle with Actuator Fault
This paper addresses the fault-tolerant control of hypersonic flight vehicle. To estimate the unknown function in flight dynamics, neural networks are employed in controller design. Moreover, in order to compensate the actuator fault, an adaptive signal is introduced in the controller design to estimate the unknown fault parameters. Simulation results demonstrate that the proposed approach could obtain satisfying performance
Fault detection and isolation of pitch actuator faults in a floating wind turbine
In this work, the problem of detection and isolation of pitch actuator faults in wind turbines (WTs) is addressed. First, interval observers are used by means of the Luenberger observer to obtain an upper and a lower estimated bounds. The main advantage of this approach is that the new bounds enclose the real output measurement within a bounded interval in a guaranteed way under consideration of the uncertainties (in this case noise in the pitch measurement). Finally, residual signals are obtained and processed to detect and isolate the different faults. The efficiency of the proposed approach is demonstrated through simulation with the 5MW floating offshore (barge) WT benchmark model given by the aero-lastic wind turbine simulator-FAST. This software is designed by the U.S. National Renewable Energy Laboratory and is widely used in research and industry.Peer ReviewedPostprint (published version
Adaptive Approximation-Based Control for Nonlinear Systems: A Unified Solution with Accurate and Inaccurate Measurements
A unified solution to adaptive approximation-based control for nonlinear
systems with accurate and inaccurate state measurement is synthesized in this
study. Starting from the standard adaptive approximation-based controller with
accurate state measurement, its corresponding physical interpretation,
stability conclusion, and learning ability are rigorously addressed when facing
additive measurement inaccuracy, and explicit answers are obtained in the
framework of both controller matching and system matching. Finally, it proves
that, with a certain condition, the standard adaptive approximation-based
controller works as a unified solution for the cases with accurate and
inaccurate measurement, and the solution can be extended to the nonlinear
system control problems with extra unknown dynamics or faults in actuator
and/or process dynamics. A single-link robot arm example is used for the
simulation demonstration of the unified solution
Trends in vehicle motion control for automated driving on public roads
In this paper, we describe how vehicle systems and the vehicle motion control are affected by automated driving on public roads. We describe the redundancy needed for a road vehicle to meet certain safety goals. The concept of system safety as well as system solutions to fault tolerant actuation of steering and braking and the associated fault tolerant power supply is described. Notably restriction of the operational domain in case of reduced capability of the driving automation system is discussed. Further we consider path tracking, state estimation of vehicle motion control required for automated driving as well as an example of a minimum risk manoeuver and redundant steering by means of differential braking. The steering by differential braking could offer heterogeneous or dissimilar redundancy that complements the redundancy of described fault tolerant steering systems for driving automation equipped vehicles. Finally, the important topic of verification of driving automation systems is addressed
An LPV Fault Tolerant control for semi-active suspension -scheduled by fault estimation
International audienceIn this paper, a novel fault tolerant control is proposed to accommodate damper faults (oil leakages) in a semi-active suspension system based on a quarter-car vehicle model. The fault accommodation is based on the Linear Parameter Varying (LPV) control strategy and involved in 2 steps. At first, a fast time-varying fault is estimated by using the fast adaptive fault estimation (FAFE) algorithm and based on an unknown input adaptive observer. Thanks to information about the estimated fault, the dissipativity domain of the semi-active suspension is adapted according to the fault. Then a single LPV fault tolerant controller is developed to manage the system performances. The controller solution, derived in the LPV/H ∞ framework, is based on the LMI solution for polytopic systems. Some simulation results are presented that show the effectiveness of this approach
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