H-infinity helicopter flight control law design with and without rotor state feedback

1994 ◽  
Vol 17 (6) ◽  
pp. 1245-1251 ◽  
Author(s):  
Marc D. Takahashi
Keyword(s):  
Flight Control ◽  
State Feedback ◽  
Control Law ◽  
H Infinity ◽  
Helicopter Flight

Flight Control Law Design via Pole Placement

2012 ◽  
Vol 466-467 ◽  
pp. 1202-1206
Author(s):  
Zheng Zai Qian ◽  
Xiao Hua Zhai
Keyword(s):  
Flight Control ◽  
State Feedback ◽  
Mathematic Model ◽  
System Stability ◽  
Pole Placement ◽  
Control Law ◽  
Flight Control System ◽  
Unstable Configuration ◽  
Static Instability ◽  
Space Description

Modern aircraft is designed generally with static unstable configuration in order to achieve the good maneuvering performance and the good controllability. Flight control law design is very important for the modern aircraft. The most importance for the flight control law is sustained flight. This paper presents a method of the state space description static instability mathematic model of modern aircraft. A new flight control law design based on pole placement and state feedback method is given in this paper also. The flight system stability and maneuverability are greatly improved through the method of the pole placement and state feedback. The simulation results show that pole placement method is very important and feasible in modern flight control system design.

Application of robust H-infinity controller in transition flight modeling of autonomous VTOL convertible Quad Tiltrotor UAV

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Navya Thirumaleshwar Hegde ◽  
V. I. George ◽  
C. Gurudas Nayak ◽  
Aldrin Claytus Vaz
Keyword(s):  
Mathematical Modeling ◽  
Flight Control ◽  
High Speed ◽  
Equations Of Motion ◽  
H Infinity ◽  
Content Type ◽  
Helicopter Flight ◽  
Aerial Vehicles ◽  
H Infinity Control ◽  
And Performance

PurposeThis paper aims to provide a mathematical modeling and design of H-infinity controller for an autonomous vertical take-off and landing (VTOL) Quad Tiltrotor hybrid unmanned aerial vehicles (UAVs). The variation in the aerodynamics and model dynamics of these aerial vehicles due to its tilting rotors are the key issues and challenges, which attracts the attention of many researchers. They carry parametric uncertainties (such as non-linear friction force, backlash, etc.), which drives the designed controller based on the nominal model to instability or performance degradation. The controller needs to take these factors into consideration and still give good stability and performance. Hence, a robust H-infinity controller is proposed that can handle these uncertainties.Design/methodology/approachA unique VTOL Quad Tiltrotor hybrid UAV, which operates in three flight modes, is mathematically modeled using Newton–Euler equations of motion. The contribution of the model is its ability to combine high-speed level flight, VTOL and transition between these two phases. The transition involves the tilting of the proprotors from 90° to 0° and vice-versa in 15° intervals. A robust H-infinity control strategy is proposed, evaluated and analyzed through simulation to control the flight dynamics for different modes of operation.FindingsThe main contribution of this research is the mathematical modeling of three flight modes (vertical takeoff–forward, transition–cruise-back, transition-vertical landing) of operation by controlling the revolutions per minute and tilt angles, which are independent of each other. An autonomous flight control system using a robust H-infinity controller to stabilize the mode of transition is designed for the Quad Tiltrotor UAV in the presence of uncertainties, noise and disturbances using MATLAB/SIMULINK. This paper focused on improving the disturbance rejection properties of the proposed UAV by designing a robust H-infinity controller for position and orientation trajectory regulation in the presence of uncertainty. The simulation results show that the Tiltrotor achieves transition successfully with disturbances, noise and uncertainties being present.Originality/valueA novel VTOL Quad Tiltrotor UAV mathematical model is developed with a special tilting rotor mechanism, which combines both aircraft and helicopter flight modes with the transition taking place in between phases using robust H-infinity controller for attitude, altitude and trajectory regulation in the presence of uncertainty.

Rotor-state feedback control design to improve helicopter turbulence alleviation in hover

2017 ◽  
Vol 232 (1) ◽  
pp. 156-168 ◽  
Author(s):  
Honglei Ji ◽  
Renliang Chen ◽  
Pan Li
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Flight Control ◽  
State Feedback ◽  
Integrated Control ◽  
State Feedback Control ◽  
Control Law ◽  
Frequency Range ◽  
Nonlinear Simulation ◽  
Stability Margins

A helicopter flight control system with rotor-state feedback to improve turbulence alleviation in hover is presented. First, a flight dynamic model coupled with turbulence model is developed and validated. Then, an integrated control strategy with a rotor-state feedback control law is proposed based on the baseline control system. The feedback gains of body and rotor states are designed in synergy to improve turbulence alleviation in the interested frequency range of handling qualities. Subsequently, the effects of the rotor-state feedback gains on both the stability of rotor dynamics and helicopter turbulence alleviation are analyzed in detail. Finally, the effectiveness of the integrated control system is evaluated with linear analysis in frequency domain and nonlinear simulation in time domain. The results indicate that with the rotor-state feedback control law integrated into the control system, the helicopter turbulence alleviation in the interested frequency range is improved with less degradation in helicopter stability margins, and the roll and pitch rate responses of helicopter to turbulence, measured with Root-Mean-Square (RMS) values, are reduced by more than 50% and 35% respectively.

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