Design Of Control System For Aircraft Research Articles

Enhanced disturbance rejection control based test rocket control system design and validation

Test rocket has been an attractive platform for scientific and educational experiments during the last several years. Aiming at providing a potential engineering application of disturbance rejection control to aircraft control system design following traditional frequency-domain methods, this paper presents an enhanced disturbance rejection control of two degrees of freedom based on H∞ synthesis and equivalent-input-disturbance (EID) for 3-axis attitude controller design of a small solid test rocket. The establishment of an EID system regards the mismatched disturbance as a ‘total disturbance’ in the input channel for compensation. The H∞ synthesis based on classical frequency-domain analysis is applied to the design of a disturbance filter and of a composite feedback controller. In terms of the controller design, the system including the filter is considered as a whole to guarantee the stability of the overall system without separate design. Furthermore, the proposed method is successfully applied to the 3-axis attitude controller design of the test rocket by modeling the nonlinear dynamics as linear EID formulations of attitudes. The simulation and validation including Monte-Carlo bias simulation and comparison with active disturbance rejection control (ADRC) based design, Hardware-in-the-Loop (HIL) simulation and flight test are conducted specifically. The results verify the effectiveness of the proposed method with excellent performance and practical prospects.

Improved disturbance rejection control based onH∞synthesis and equivalent-input-disturbance for aircraft longitudinal autopilot design

Disturbance rejection control has been developed over decades attracting wide interest and research attention. Aiming at providing a potential engineering application of disturbance rejection control to aircraft control system design following traditional frequency-domain methods, this paper presents an improved disturbance rejection control of two degrees of freedom based on [Formula: see text] synthesis and equivalent-input-disturbance for an aircraft longitudinal autopilot design. The mismatched disturbance is transformed as a “total disturbance” in the input channel for compensation through the establishment of an equivalent-input-disturbance system. The [Formula: see text] synthesis based on classical frequency-domain analysis is applied to a disturbance filter and a composite feedback controller design. In terms of the controller design, the system including the filter is considered as a whole in [Formula: see text] optimization process without separate design to guarantee the stability of the overall system. Furthermore, the proposed method is successfully implemented on the autopilot design by modeling nonlinear aircraft longitudinal dynamics as a linear equivalent-input-disturbance formulation of angle of attack. The simulation of tracking performance in comparison with existing renowned methods is conducted in the presence of aerodynamic uncertainties, gust disturbance, actuator characteristics and sensor noise. The results verify the effectiveness of the proposed method with excellent performance and practical prospects.

To a problem of aircraft control system design with given dynamic parameters

In the design of an aircraft at the stage of selecting its geometrical parameters, a method is proposed for evaluating the performance capabilities of manual control to ensure the quality of a given flight stabilization mode. The attainability of the given aircraft-pilot dynamic properties is evaluated by a frequency-domain method for permissible values of the aircraft and the pilot model parameters. The quality of the manual control for the longitudinal motion of the aircraft is evaluated.

一类高超声速飞行器自适应容错控制器设计

The hypersonic aircraft control system design must deal with the extra prominent dynamics characteristics: highly coupled, strongly nonlinear, time variational and so on. Thus, during the course of control system study and design for the hypersonic aircraft, the following factors must be considered: plant elastic deformation, multi-inputs multi-outputs, uncertain aerodynamatic parameters, sensors and actuator failures, which is differ from the traditional aircrafts control system design. To solve the failure problem of the actuator in the course of the hypersonic aircraft flight, one kind of adaptive backstepping fault-tolerant control method based on the observer and controller designed synthetically is brought up. At first, we develop the research model based on a SISO output feedback nonlinear unobservered minimum phase system under the condition of single channel actuator failure of the hypersonic aircraft, then adopt K -filter to reconstruct state vectors. When only the output is measureable, the dissertation designs one new observer to estimate convergence state vector and design the adaptive control law to guarantee the system boundedness. In the course of adaptive backstepping design, the dissertation employes the dynamic surface control strategy to eliminate the explosion of terms by introducing a series of first order filters to obtain the differentiation of the virtual control inputs. Lyapunov stability theorem guarantees the error uniformly bound. Both theory analysis and simulation verification show the simplicity and effectiveness of this method. At last the pitch channel of hypersonic aircraft is studied as an example to validate the above theory.

Robust thrust-only control of a civil transport aircraft with vertical tail damage

Abstract Thrust-only control of a jet transportation aircraft is also referred to as propulsion-controlled aircraft (PCA). It may be adopted as an alternative to using propulsive force to provide a certain level of control capability in case of failure of the aircraft's conventional control system. Previous PCA research was mainly concerned with control surface malfunctions such as free-floating and locked-in-place situations. On the other hand, structural damage to the aircraft control surfaces makes it necessary for PCA study and results in significant challenges due to the damage-induced aerodynamic and geometric parameter deviations. This paper presents a damage-tolerant control system design for aircraft with vertical tail damage. An H∞ loop transfer recovery (LTR) technique is applied to address the stability recovery and robustness of performance in maintaining safe flight operation of a damaged aircraft. Modelling of the damaged flight dynamics and control design is presented followed by numerical...

Sensitivity Reduction in Aircraft Control Systems

A method for reducing trajectory sensitivity to parameter perturbations for linear feedback systems is described. Application of the method to the design of aircraft control systems, with special reference to a helicopter forward flight control system, is illustrated. The response of the system based on this method is found to be better than that obtained with fixed-feedback gain controllers, although the response may not be as good as that of an adaptive control scheme. The main advantage of the method is the simplicity of its implementation relative to that of the adaptive control scheme which requires an on-board computer.

Wind Modeling and Lateral Control for Automatic Landing

For the purposes of aircraft control system design and analysis, the wind can be characterized by a mean com- ponent which varies with height and by turbulent components which are described by the von Karman correlation model. The aircraft aerodynamic forces and moments depend linearly on uniform and gradient gust components obtained by averaging over the aircraft's length and span. The correlations of the averaged com- ponents are then approximated by the outputs of linear shaping filters forced by white noise. The resulting model of the crosswind shear and turbulence effects is used in the design of a lateral control system for the automatic landing of a DC-8 aircraft. NE of the more challenging problems facing an autopilot designer is the synthesis of feedback logic which will achieve the desired attitude and position of an aircraft at touchdown in the presence of turbulent crosswinds. During the approach phase of an automatic landing, the desired flight path is maintained by heading slightly into the prevailing crosswind (crabbing). However, at touchdown, the aircraft centerline must be aligned with the runway to prevent lateral skidding of the wheels on the landing gear. The transition from the approach attitude to the touchdown attitude, termed the maneuver, is usually carried out by the pilot, using the rudder to reduce the heading deviation, and ailerons to dip the windward wing tip sightly so as to maintain the lateral position in the presence of the resulting aerodynamic sideslip. When visibility is reduced to the point where the pilot cannot maintain the required visual reference, it is desirable to perform the decrab maneuver automatically. In order to carry out an effective automatic landing, ac- curate information on the aircraft's attitude and position is required. In the last several years, accurate and reliable navigation systems have been developed to provide this in- formation. Such systems include inertially augmented ILS systems,1'2 microwave landing systems, MLS,3 and various attitude reference systems.4 It is anticipated that further im- provements in system accuracy and reliability will be made in the future. Touchdown errors in automatic landing are also caused by turbulent winds. In contrast with the navigation errors, there is little hope of reducing these disturbances. In fact, as lan- ding speeds are lowered, as in STOL aircraft applications, the wind effects become more pronounced.

Optimal Control Theories in the Design of Aircraft Stability Augmentation and Control Systems

This paper outlines modern optimal control theory and its possible application to the design of some aircraft control systems. Both continuous and discrete control laws are considered. Deterministic linear systems with a quadratic index of performance (state feedback) are discussed and extended to real and implicit model-following. Output feedback control laws are introduced using gain matrices and state observers, leading to the (Stochastic) Kalman-Bucy filter. The effects of plant parameter variation with flight condition are related to the design of ‘desensitised’ control laws. Comment is also made on suitable state variable models.