scholarly journals Sliding Mode Implementation of an Attitude Command Flight Control System for a Helicopter in Hover

10.14311/748 ◽  
2005 ◽  
Vol 45 (4) ◽  
Author(s):  
D. J. McGeoch ◽  
E. W. McGookin ◽  
S. S. Houston

This paper presents an investigation into the design of a flight control system, using a decoupled non-linear sliding mode control structure, designed using a linearised, 9th order representation of the dynamics of a PUMA helicopter in hover. The controllers are then tested upon a higher order, non-linear helicopter model, called RASCAL. This design approach is used for attitude command flight control implementation and the control performance is assessed in the terms of handling qualities through the Aeronautical Design Standards for Rotorcraft (ADS-33). In this context a linearised approximation of the helicopter system is used to design an SMC control scheme. These controllers have been found to yield a system that satisfies the Level 1 handling qualities set out by ADS-33. 

2012 ◽  
Vol 468-471 ◽  
pp. 529-533 ◽  
Author(s):  
Fu Yang Chen ◽  
Wen Li Luan ◽  
Rui Hou

In this paper, an adaptive control scheme is proposed for the uncertain flight control system of the helicopter with fault in vertical flight. The controller is designed using sliding mode theory and adaptive technology. In the controller, the nonlinear function is brought in, which can enlarge the small errors, and saturate the large errors. And it can make sure the good transient performances and stability of the helicopter flight control system. Finally, the simulation results of the nonlinear helicopter flight system illustrate the effectiveness and feasibility of the proposed scheme in the paper.


Author(s):  
Majeed Mohamed ◽  
Madhavan Gopakumar

The evolution of large transport aircraft is characterized by longer fuselages and larger wingspans, while efforts to decrease the structural weight reduce the structural stiffness. Both effects lead to more flexible aircraft structures with significant aeroelastic coupling between flight mechanics and structural dynamics, especially at high speed, high altitude cruise. The lesser frequency separation between rigid body and flexible modes of flexible aircraft results in a stronger interaction between the flight control system and its structural modes, with higher flexibility effects on aircraft dynamics. Therefore, the design of a flight control law based on the assumption that the aircraft dynamics are rigid is no longer valid for the flexible aircraft. This paper focuses on the design of a flight control system for flexible aircraft described in terms of a rigid body mode and four flexible body modes and whose parameters are assumed to be varying. In this paper, a conditional integral based sliding mode control (SMC) is used for robust tracking control of the pitch angle of the flexible aircraft. The performance of the proposed nonlinear flight control system has been shown through the numerical simulations of the flexible aircraft. Good transient and steady-state performance of a control system are also ensured without suffering from the drawback of control chattering in SMC.


Aerospace ◽  
2019 ◽  
Vol 6 (3) ◽  
pp. 27 ◽  
Author(s):  
Manuel Pusch ◽  
Daniel Ossmann ◽  
Tamás Luspay

The model-based flight control system design for a highly flexible flutter demonstrator, developed in the European FLEXOP project, is presented. The flight control system includes a baseline controller to operate the aircraft fully autonomously and a flutter suppression controller to stabilize the unstable aeroelastic modes and extend the aircraft’s operational range. The baseline control system features a classical cascade flight control structure with scheduled control loops to augment the lateral and longitudinal axis of the aircraft. The flutter suppression controller uses an advanced blending technique to blend the flutter relevant sensor and actuator signals. These blends decouple the unstable modes and individually control them by scheduled single loop controllers. For the tuning of the free parameters in the defined controller structures, a model-based approach solving multi-objective, non-linear optimization problems is used. The developed control system, including baseline and flutter control algorithms, is verified in an extensive simulation campaign using a high fidelity simulator. The simulator is embedded in MATLAB and a features non-linear model of the aircraft dynamics itself and detailed sensor and actuator descriptions.


2011 ◽  
Vol 128-129 ◽  
pp. 142-145
Author(s):  
Yong Hua Fan ◽  
Xin Li ◽  
Yun Feng Yu

The high altitude airship can not have desired performance to control the altitude rapidly and accurately when the elevator or ancillary air bursa charge or deflation is used only, because the elevator has little efficiency when the velocity is low and auxiliary air bursas charge or deflation control is very slow. It is present a method to design flight control system for a high altitude airship using auxiliary air bursas charge or deflation and elevator combination control. This combination control scheme is that the ancillary air bursa and elevator are also used to control the airship attitude to get large raise velocity and the ancillary air bursa control is used to adjust the airship altitude for suspension. In this paper, a high altitude airship model with compound control of elevator and ancillary air bursa charge and deflation is given firstly. Then the combination controller is designed by using fuzzy self-tuning control. Finally, it has been proved by simulation that the flight control system has desirable performance and the compound control scheme is feasible.


Author(s):  
Yasser Bouzid ◽  
Houria Siguerdidjane ◽  
Yasmina Bestaoui

The performance of any flight control system strictly depends on the feedback control scheme. In this article, two redundant controllers that could be implemented without much difficulty are proposed to boost and improve the capabilities of the popular feedback linearization controller. The first one is built upon the model-free control theory while the second one is based on the sliding mode framework. Herein, the model-free control principle is used to deal with the unknown part of the plant only (i.e. unmodeled dynamics, disturbances, etc.) in addition to the feedback linearization controller that is used instead of the proportional–integral–derivative structure. Unlike the existing sliding mode techniques, the designed one uses an input-dependent sliding surface. An in-depth discussion is highlighted with detailed evaluation in terms of performance, consumed energy, and robustness by considering several scenarios and using several metrics. The numerical simulations have shown satisfactory results considering multi-input multi-output system model through an application to a small quadrotor. The effectiveness of this approach is validated by experimentation.


2017 ◽  
Vol 89 (6) ◽  
pp. 764-776 ◽  
Author(s):  
Zhi Chen ◽  
Daobo Wang ◽  
Ziyang Zhen ◽  
Biao Wang ◽  
Jian Fu

Purpose This paper aims to present a control strategy that eliminates the longitudinal and lateral drifting movements of the coaxial ducted fan unmanned helicopter (UH) during autonomous take-off and landing and reduce the coupling characteristics between channels of the coaxial UH for its special model structure. Design/methodology/approach Unidirectional auxiliary surfaces (UAS) for terminal sliding mode controller (TSMC) are designed for the flight control system of the coaxial UH, and a hierarchical flight control strategy is proposed to improve the decoupling ability of the coaxial UH. Findings It is demonstrated that the proposed height control strategy can solve the longitudinal and lateral movements during autonomous take-off and landing phase. The proposed hierarchical controller can decouple vertical and heading coupling problem which exists in coaxial UH. Furthermore, the confronted UAS-TSMC method can guarantee finite-time convergence and meet the quick flight trim requirements during take-off and landing. Research limitations/implications The designed flight control strategy has not implemented in real flight test yet, as all the tests are conducted in the numerical simulation and simulation with a hardware-in-the-loop (HIL) platform. Social implications The designed flight control strategy can solve the common problem of coupling characteristics between channels for coaxial UH, and it has important theoretical basis and reference value for engineering application; the control strategy can meet the demands of engineering practice. Originality/value In consideration of the TSMC approach, which can increase the convergence speed of the system state effectively, and the high level of response speed requirements to UH flight trim, the UAS-TSMC method is first applied to the coaxial ducted fan UH flight control. The proposed control strategy is implemented on the UH flight control system, and the HIL simulation clearly demonstrates that a much better performance could be achieved.


2009 ◽  
Vol 147-149 ◽  
pp. 231-236 ◽  
Author(s):  
Tomasz Rogalski ◽  
Andrzej Tomczyk ◽  
Grzegorz Kopecki

At the Department of Avionics and Control Systems problems of aeronautical control systems have been dealt with for years. Several different kinds of aeronautical control systems have been designed, prototyped and tested. These control systems are intended for general aviation aircraft and unmanned aircraft. During all research projects computer simulations and laboratory tests were made. However, since in some cases such tests were insufficient, in-flight tests were conducted leading to a series of reliable results. The in-flight tests were made with the use of M-20 Mewa aircraft (autopilot for a GA aircraft) and PZL-110 Koliber aircraft (control system for UAV and indirect flight control system for a GA aircraft). Nevertheless, in-flight testing is very expensive and problematic. To avoid some problems appearing during in-flight tests and their preparation, a simulator – which is normally used for professional pilot training – can be used. The Aviation Training Center of the Rzeszów University of Technology possesses the ALSIM AL-200 MCC flight simulator. We have started preparing this simulator for the research. It is possible to control the simulated aircraft with the use of an external control system. The solution proposed enables testing the aircraft control algorithms, indirect control laws (e.g. control laws modifying handling qualities), as well as testing and assessment of the students’ pilotage skills. Moreover, the solution makes it possible to conduct tests connected with aircraft control, crew management, crew cooperation and flight safety. The simulator allows us to test dangerous situations, which – because of safety reasons – is impossible during in-flight testing. This paper presents modifications to the simulator’s hardware and additional software, which enable the described research.


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