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This paper is concerned with the problem of designing adaptive actuator fault estimation scheme for linear discrete-time systems. The general methodology is focused on designing a robust fault estimation strategy with a quadratic boundedness approach which is used to guarantee the convergence of the proposed state and fault estimation scheme. The novelty of the proposed approach is that robustness...
Sensor placement is of pivotal importance in closed-loop control as measurements are key to design the control laws. In this article, a novel machine learning-based sensor placement algorithm is proposed in order to recover a high-dimensional field from a limited amount of local measurements with a linear estimator. Unlike many other methods, our algorithm does not rely on a reduced order model and...
In this paper, a novel sliding mode-based control approach is proposed for a full vehicle suspension system subject to actuator faults and model uncertainties. The underlying design concept is to retain system stability and reliability in the presence of actuator faults, parameter variations and neglected nonlinear effects. The proposed approach is based on a new variable structure control, derived...
This paper proposes an approach for actuator and sensor selection for a small flexible aircraft. The approach is based on the synthesis of robust controllers accounting for model uncertainty. The objective is to find, out of a finite set of actuator/sensor configurations available in the aircraft, the best configuration that provides sufficient robustness and desired performance. The results show...
A challenging problem for adaptive control systems is the accurate characterization of the transient response in the presence of dynamic uncertainties such as a partially known actuator. Considering an actuator modelled as a first order filter with an uncertain control effectiveness and using a projection mechanism for parameters adaptation, we show that the tracking error dynamics behaves as a linear...
Wind turbine system is a safety-critical system, which has the demand to improve the operating reliability and reducing the cost caused by the shut-down time and component repairing. As a result, condition monitoring and fault diagnosis have received much attention for wind turbine energy systems. Noticing that environmental disturbances are unavoidable, therefore how to improve the robustness of...
This paper presents an improved phase lead repetitive compensator (RC) for a linear actuator (LA) system. The linear phase lead compensation provided by the proposed compensator structure compensates the phase lag of the feedback system caused by payload variations and nonlinear friction present in the LA system. Unlike conventional phase lead RC structures which use a pure linear phase advance compensator...
In this paper, two criteria for robust actuator fault reconstruction with sliding mode observation for a class of uncertain nonlinear systems are derived. It is known, even though the sliding mode technique is robust against unknown but bounded uncertainties, that the quality of fault reconstruction under real conditions is not as good as assumed in the design stage. This is often due to the fact...
The main objective of this paper is to perform a robust controller design using discrete-time sliding mode control (DSMC). In the control scheme, two-degree-of-freedom (2-DOF) control strategy turns the DSMC, which generally utilized state feedback into output feedback controller. The designed control scheme is considered with feedback and feedforward combination by implementing the zero phase error...
The adoption of fault detection and isolation (FDI) techniques is fundamental to ensure high levels of safety and productivity, especially in critical and expensive applications like Autonomous Underwater Vehicles (AUV). This paper describes a comparison between different techniques available in the literature, applied to over-actuated AUVs under single fault condition (SFC) and considering only abrupt...
A series elastic actuator (SEA) consists of a system with an intrinsically compliant mechanism, and introduces the possibility of external force/torque sensing and control. However, this mechanism is also known to reduce torque servo-control bandwidth and to separate link-side dynamics from actuator-side dynamics. The conventional solution to overcoming reduced actuation bandwidth and separated link...
A robot and its dynamical actuators are mathematically modelled in a general form of a 3D system without any particular information either about system parameters and nonlinearities or about external disturbances. A demanded system tracking quality is global elementwise q-tracking without oscillations and with a requested finite reachability time. It is described by a vector differential equation...
This paper investigates the problem of robust stabilization of uncertain saturating actuator systems with a time-varying delay in both state and control. Employing the Razumikhin approach for the stability of functional differential equations, upper bounds on the time-varying delay are proposed such that the considered uncertain system is robustly globally or locally asymptotically stabilizable via...
In this paper, we are interested in missile autopilot design. Our objective is to seek the approaches which significantly enhance the ability of a control engineer to deal with practical nonlinear control problem. For this purpose, two nonlinear methods are considered: «approximate feedback » and « approximate dynamic feedback » with two time-scale separation. Both methodologies are applied in order...
In this paper, a non linear autopilot for a missile pitch axis is designed over a wide flight envelope. The controller is obtained by a Linear Parametrically Varying (LPV) synthesis applied to the H¥/loop-shaping criterion. The resulting controller depends on the angle of attack, the Mach number and the altitude. Robust stability and performance are firstly checked by means of linear analysis and...
In recent years several approaches have been proposed to compensate for the hysteresis behavior of piezo actuators. However, they are very restrictive, either on the hardware side or in the choice of possible reference trajectories. In this paper, alternative hysteresis compensators for arbitrary trajectories are presented which use standard equipment. Two approaches of different complexity are proposed...
The main problem in controlling real aircraft is information lack, external disturbances and mathematical model inaccuracy. However, combining both high precision and robustness, standard sliding modes feature high-frequency control switching causing the so-called chattering effect. The controller considered in the present paper is based on 2-sliding modes and produces bounded control continuously...
This article presents the design for a Fault Detection and Isolation system applied to the actuator consisting in a hydraulic screw-down device used for automated running of rolling mill stands in the iron and steelmaking industry. The actuator is first described and specifications for the monitoring are proposed. The principles of the design are developed giving the main parameters to adjust with...
This paper is devoted to the control system design and implementation of an industrial DVD-video drive. A standard H∞ approach is proposed to control the linear displacement of the optical head actuator along the disc radius, and to reduce the effect of external disturbances affecting the system, like eccentricity and vertical deviations. Uncertainty model, based on a parametric description of the...
Actuator constraint handling is necessary for many cross-directional controllers. We discuss how optimal steady state performance can be guaranteed by modifying an internal model control structure with a non-linear element. For the simple dynamics associated with most web processes this also gives good closed-loop dynamic behaviour. Thus unconstrained control design techniques may be applied directly...
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