Development of a control law to improve the handling qualities for short-range air-to-air combat maneuvers

2020 ◽  
Vol 12 (7) ◽  
pp. 168781402093679
Author(s):  
Chong-Sup Kim ◽  
Chang-Ho Ji ◽  
Byoung Soo Kim
Keyword(s):  
Flight Control ◽  
Short Range ◽  
Control Method ◽  
Control Law ◽  
Fighter Aircraft ◽  
Handling Qualities ◽  
Flying Qualities ◽  
Air Combat ◽  
Handling Quality ◽  
The Mathematical Model

Modern fighter aircraft have been designed to have high maneuverability in order to preoccupy strategic superiority in short-range air-to-air combat between fighter aircraft in warfare. Digital fly-by-wire flight control system design is aimed at providing good handling qualities for all mission task elements over the entire flight envelope. To provide both excellent gross acquisition and fine tracking compatibility, simultaneously for air-to-air combat maneuvers, this article presents a common longitudinal control law design of a task-dependent self-adjusting command-path pilot prefilter gain scheduler within the same control law design architecture and response type based on nonlinear dynamic inversion control. We perform the frequency- and time-domain analyses based on the mathematical model of T-50 advanced trainer aircraft to evaluate the basic flying qualities of the proposed control method. Furthermore, the pilot evaluation is performed to evaluate the gross acquisition and fine tracking capability for air-to-air tracking maneuvers in a handling quality simulator. The evaluation results reveal that the proposed control method improves the fine tracking capability without the degradation of gross acquisition.

Supersonic transport aircraft longitudinal flight control law design

2004 ◽  
Vol 108 (1084) ◽  
pp. 319-329
Author(s):  
A. J. Steer
Keyword(s):  
Flight Control ◽  
Dynamic Inversion ◽  
Control Law ◽  
Transport Aircraft ◽  
Handling Qualities ◽  
Supersonic Transport ◽  
Linear Dynamic ◽  
Non Linear ◽  
Quality Design ◽  
Handling Quality

Abstract Modern civil transport aircraft utilise increasingly complex command and stability augmentation systems to restore stability, optimise aerodynamic performance and provide the pilot with the optimum handling qualities. Provided it has sufficient control power a second generation fly-by-wire supersonic transport aircraft should be capable of exhibiting similarly desirable low-speed handling qualities. However, successful flight control law design requires identification of the ideal command response type for a particular phase of flight, a set of valid handling quality design criteria and piloted simulation evaluation tasks and metrics. A non-linear mathematical model of the European supersonic transport aircraft has been synthesized on the final approach to land. Specific handling quality design criteria have been proposed to enable the non-linear dynamic inversion flight control laws to be designed, with piloted simulation used for validation. A pitch rate command system, with dynamics matched to the aircraft’s flight path response, will consistently provide Level 1 handling qualities. Nevertheless, pre-filtering the pilot’s input to provide a second order pitch rate response, using the author’s suggested revised constraints on the control anticipation parameter will generate the best handling qualities during the terminal phase of flight. The resulting pre-filter can be easily applied to non-linear dynamic inversion inner loop controllers and has simple and flight proven sensor requirements.

Control law design to improve the unexpected pitch motion in slow down turn maneuver

2021 ◽  
pp. 095441002110086
Author(s):  
Chong-sup Kim ◽  
Taebeom Jin ◽  
Gi-oak Koh ◽  
Byoung soo Kim
Keyword(s):  
Control System ◽  
Angular Acceleration ◽  
Control Law ◽  
Fighter Aircraft ◽  
Pitch Motion ◽  
Flying Qualities ◽  
Aircraft System ◽  
The Stability ◽  
The Time Domain ◽  
The Mathematical Model

The highly maneuverable fighter aircraft is exposed to unexpected pitch motion such as over-Nz (normal acceleration) and Nz-drop characteristics in transonic and supersonic flight conditions with moderate angle of attack. These characteristics not only degrade flying qualities by destabilizing the aircraft but also threaten flight safety by increasing the structural load. This article proposes an additional augmentation control in the incremental nonlinear dynamic inversion structure, which feeds back the error of pitch angular acceleration to mitigate unexpected pitch motion in slow down turn maneuver. We evaluate the stability, flying qualities, and robustness of the proposed control system by performing the frequency-domain linear analysis and the time-domain numerical simulations based on the mathematical model of advanced trainer aircraft. As a result of the evaluation, the additional augmentation control further improves flying qualities and deceleration performance of the aircraft by decreasing over-Nz and Nz-drop characteristics in high-Nz maneuvering in the transonic flight condition as well as ensuring the stability and robustness of the control system against the major uncertainty factors of the aircraft system compared to the existing transonic pitching moment compensation (TPMC) control in which the predefined scheduling for Nz feedback is used.

scholarly journals Longitudinal flight control design with handling quality requirements

2006 ◽  
Vol 110 (1111) ◽  
pp. 627-637 ◽  
Author(s):  
D. Saussié ◽  
L. Saydy ◽  
O. Akhrif
Keyword(s):  
Flight Control ◽  
Control Law ◽  
Longitudinal Motion ◽  
Model Order ◽  
Quality Requirements ◽  
Loop Design ◽  
Business Jet ◽  
Stability Augmentation ◽  
Handling Quality ◽  
And Control

Abstract This work presents a method for selecting the gain parameters of a C* control law for an aircraft’s longitudinal motion. The design incorporates various handling quality requirements involving modal, time- and frequency-domain criteria that were fixed by the aircraft manufacturer. After necessary model order-reductions, the design proceeds in essentially two-steps: stability augmentation system (SAS) loop design and control augmentation system (CAS) loop design. The approach partly relies on the use of guardian maps to characterise, in each case, the set of gain parameters for which desired handling quality requirements are satisfied. The approach is applied throughout the full flight envelope of a business jet aircraft and yields satisfactory results.

Piloted Handling Qualities Evaluation of an OBLTR Prototype Flight Control Law at the USAF Test Pilot School

2019 ◽  
Author(s):  
M Christopher Cotting ◽  
Erin Alt ◽  
Catherine Chappell ◽  
Brian Heemstra ◽  
David Guerrero ◽  
...  
Keyword(s):  
Flight Control ◽  
Control Law ◽  
Handling Qualities ◽  
Pilot School

Preliminary parameters design for a long endurance unmanned helicopter with low rotor-disc loading

2020 ◽  
pp. 095441002097389
Author(s):  
Hong Zhao ◽  
Jian-Bo Li ◽  
Yuan Wang ◽  
Zhi-Gang Wang
Keyword(s):  
Flight Control ◽  
Evaluation Model ◽  
Load Ratio ◽  
Collaborative Optimization ◽  
Flight Performance ◽  
Unmanned Helicopter ◽  
Handling Qualities ◽  
Flying Qualities ◽  
Long Endurance ◽  
Quality Evaluation Model

This paper investigates the design of a long-endurance unmanned helicopter (LEUH) with low rotor disc loading (LRDL) and low rotor speed (LRS). Due to the flaws in flying qualities caused by the LRDL and the LRS, this paper establishes a flying quality evaluation model in which handling qualities (FQs) and flight control (FC) are introduced into the distributed multi-objective collaborative optimization (DMOCO) of the helicopters. The comprehensive design optimization on preliminary parameters of the LEUH in wind shear is also carried out. Numerical simulation results show that the LRDL and the LRS technologies are successfully applied to LEUH, with the FQs and the flight performance considered. Compared with A160 LEUH, the payload load ratio is significantly improved.

Robust scheduled control of longitudinal flight with handling quality satisfaction

2011 ◽  
Vol 115 (1165) ◽  
pp. 163-174 ◽  
Author(s):  
D. Saussié ◽  
C. Bérard ◽  
O. Akhrif ◽  
L. Saydy
Keyword(s):  
Control Systems ◽  
Flight Control ◽  
Modal Control ◽  
Control Laws ◽  
Handling Qualities ◽  
Control Techniques ◽  
Centre Of Gravity ◽  
Modern Methods ◽  
Handling Quality ◽  
Scheduling Technique

AbstractClassic flight control systems are still widely used in the industry because of acquired experience and good understanding of their structure. Nevertheless, with more stringent constraints, it becomes difficult to easily fulfil all the criteria with these classic control laws. On the other hand, modern methods can handle many constraints but fail to produce low order controllers. The following methodology proposed in this paper addresses both classic and modern flight control issues, to offer a solution that leverages the strengths of both approaches. First, anH∞synthesis is performed in order to get controllers which satisfy handling qualities and are robust with respect to mass and centre of gravity variations. These controllers are then reduced and structured by using robust modal control techniques. In conclusion, a self-scheduling technique is described that will schedule these controllers over the entire flight envelope.

Optimization of Satellite Momentum Wheel Control System Based on Genetic Programming

2013 ◽  
Vol 748 ◽  
pp. 771-778
Author(s):  
Yu Song Huang ◽  
Yun Feng Dong
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Genetic Programming ◽  
Design Process ◽  
Attitude Control ◽  
Control Method ◽  
Complex Structure ◽  
Control Law ◽  
Reaction Wheel ◽  
The Mathematical Model

Due to reliability requirements, the reaction wheel actuator of the satellite attitude control system always use traditional control method. For the satellite which has complex structure, it's difficult to build the mathematical model with classical control method. The selection of control parameters is also difficult. The design process last long and the model have poor adaptability when the parameters change. Compare to genetic algorithms, genetic programming which have the capabilities to evolve automatically, have the advantage of being able to optimize the structure of the mathematical model. Results of optimization and simulation show that design the reaction wheel actuator control law with genetic programming can simplify the design process. And the evolved control law is better than traditional PD control law.

Flight Control Design for the Systematic Improvement of Ride Qualities

2020 ◽  
Author(s):  
Tobias Rath ◽  
Walter Fichter
Keyword(s):  
Flight Control ◽  
Design Procedure ◽  
Control Design ◽  
Ride Quality ◽  
Handling Qualities ◽  
Systematic Improvement ◽  
Atmospheric Disturbances ◽  
History Of ◽  
Quality Specifications ◽  
Handling Quality

The reduction of rotor-induced vibrations has been a major concern in the history of helicopter engineering. This has led to the development of numerous countermeasures, which cause the vibration levels to decrease considerably. Recent findings have shown that the reduced level of rotor vibrations highlights the importance of turbulence for the ride qualities. The rejection of atmospheric disturbances is a key task of the flight control system (FCS). However, the FCS design is currently focused on stability and handling qualities rather than ride qualities. This work addresses this shortcoming by the introduction of a systematic control design procedure. The improvement of ride qualities is achieved by linking an existing discomfort criterion to parameters of the sensitivity function. This allows the systematic modification of these parameters according to their contribution to discomfort. The approach is embedded into a design framework for systematic compliance with stability and handling quality specifications. The procedure is applied to the control design of a light helicopter resulting in considerably improved ride qualities, while compliance with stability and handling quality specifications is maintained. This represents an important step towards a more comprehensive ride quality engineering for rotorcraft that goes beyond the reduction of rotor-induced vibrations.

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