Fly-by-wire robustness to flight dynamics change under horizontal stabiliser damage

2016 ◽  
Vol 120 (1228) ◽  
pp. 1005-1023 ◽  
Author(s):  
Z. Dlamini ◽  
T. Jones
Keyword(s):  
Control System ◽  
Damage Tolerance ◽  
Flight Dynamics ◽  
Loss Of Stability ◽  
Handling Qualities ◽  
Damage Modelling

ABSTRACTAircraft damage modelling was conducted on a Boeing 747 to examine the effects of asymmetric horizontal stabiliser loss on the flight dynamics of a commercial Fly-by-Wire (FBW) aircraft. Robustness of the control system is investigated by analysing how characteristic eigenvalues move as a result of damage and comparison to the non-FBW aircraft is made. Furthermore, the extent of stabiliser loss that the system can successfully handle without loss of stability and acceptable performance is identified. The presented analysis of the results gives insightful knowledge to aid in the design of an improved FBW system with increased damage tolerance. A handling qualities evaluation is presented to provide an understanding of how the pilot perceives the damaged aircraft. The results of the study show that a generic FBW system improves robustness such that the aircraft is stable with 50% horizontal stabiliser loss. With 50% damage, the aircraft is controllable but unsafe to fly and may be unable to effectively complete its mission task.

Integrated Aircraft Modeling Research for Accurate Flight Control System Design

2013 ◽  
Vol 791-793 ◽  
pp. 658-662
Author(s):  
Chao Zhang ◽  
Yi Nan Liu ◽  
Jian Hui Xu
Keyword(s):  
Control System ◽  
System Design ◽  
Flight Control ◽  
Time Delays ◽  
Flight Dynamics ◽  
Control System Design ◽  
Control Law ◽  
Flight Control System ◽  
Aircraft Model ◽  
Simulation Results

In order to realize accurate flight control system design and simulation, an integrated scheme of aircraft model which consists of flight dynamics, fly-by-wire (FBW) platform and flight environment is proposed. Flight environment includes gravity, wind, and atmosphere. And the actuator and sensors such as gyroscope and accelerometer models are considered in the FBW platform. All parts of the integrated model are closely connected and interacted with each other. Simulation results confirm the effectiveness of the integrated aircraft model and also indicate that the (Flight Control Law) FCL must be designed with robustness to sensor noise and time delays with the FBW platform in addition to the required robustness to model uncertainty in flight dynamics.

The Heavy Assault Transport Helicopter

1966 ◽  
Vol 70 (670) ◽  
pp. 914-922
Author(s):  
R. B. Lightfoot
Keyword(s):  
Control System ◽  
Flight Control ◽  
Structural Integrity ◽  
Operating Cost ◽  
Maximum Level ◽  
Main Rotor ◽  
Handling Qualities ◽  
Level Flight ◽  
Integrity Tests ◽  
The Military

SummaryThe military tactics of vertical envelopment require the transport of 8000 pounds of payload to a radius of 100 nautical miles at a speed of 150 knots. The aircraft should be able to hover at 6000 feet on a standard day and with one engine inoperative maintain level flight in turbulent air. The helicopter should be readily convertible to carry cargo or troops.The CH-53A meets these requirements. Additional design constraints, including emergency water landing, rear loading, self-contained navigation system and weight and dimensions compatible with aircraft carriers have been imposed.With special attention having been given to the vibrational environment two General Electric T-64 engines have been installed. The 72-foot diameter main rotor is equipped with six blades with 26 inch chord and a NACA 0012 aerofoil modified to improve the characteristics at high Mach number. To achieve low drag and interference the fuselage and rotors have been developed in the wind tunnel. Tail surfaces have been especially developed to provide good handling qualities. An automatic stabilisation system was provided to relieve the pilot of various flight duties and to permit him to give more attention to the military situation.Special design procedures have been followed to control weight, drag, reliability and vibration. The final helicopter is within 3-7 per cent of the desired weight and the performance is in substantial accord with predictions. The vibration level is generally about ±0-10 g throughout the cockpit and cabin.During the flight development phase the control system was modified to provide appropriate coupling to relieve the pilot and automatic flight control system of any unnecessary compensating control motions. The structural integrity tests revealed the need for improvement of the main rotor blade attachment spindle. The engine-to-transmission shafting required a damped support.The finally developed version of the CH-53A meets the mission requirements already stated. The hovering ceiling on a standard day Is over 5000 feet. The maximum level flight speed is 170 kt. The handling qualities and vibration are superior to any helicopter previously built by Sikorsky Aircraft. The reliability and maintenance features have been demonstrated by extensive testing. The overhaul periods will be 1200 hours in early service operation; 5-5 direct maintenance man-hours per flight hour are required to accomplish all maintenance except overhaul of repairable components. The dynamic components have been developed to such a high degree of reliability that they will be overhauled “on condition” only and continued in service throughout the normal military usage.In terms of commercial service, the CH-53A (S-65) will have a direct operating cost of approximately 4c per seat mile.

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
Keyword(s):  
Control System ◽  
Flight Control ◽  
Sliding Mode ◽  
Flight Control System ◽  
Design Standards ◽  
Handling Qualities ◽  
Control Scheme ◽  
Non Linear ◽  
Order Representation ◽  
Control Implementation

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. 

scholarly journals Propeller control strategy for coaxial compound helicopters

2018 ◽  
Vol 233 (10) ◽  
pp. 3775-3789 ◽  
Author(s):  
Ye Yuan ◽  
Douglas Thomson ◽  
Renliang Chen
Keyword(s):  
Control Strategy ◽  
High Speed ◽  
High Performance ◽  
Control Strategies ◽  
Flight Dynamics ◽  
Axial Thrust ◽  
Handling Qualities ◽  
Speed Range ◽  
Compound Helicopter ◽  
Flight Dynamics Model

The coaxial compound configuration has been proposed as a concept for future high-performance rotorcraft. The co-axial rotor system does not require an anti-torque device, and a propeller provides axial thrust. A well-designed control strategy for the propeller is necessary to improve the performance and the flight dynamics characteristics. A flight dynamics model of coaxial compound helicopter is developed to analyze these influences. The performance and the flight dynamics characteristics in different propeller strategies were first investigated. The results show that there is an improvement in the performance in high-speed flight when the propeller provides more propulsive forces. It also illustrates that a reasonable allocation of the rotor and the propeller in providing thrust can further reduce the power consumption in the mid speed range. In other words, the propeller control strategy can be an effective method to improve the cruise-efficiency. The flight dynamics analysis in this paper includes trim and handling qualities. The trim results prove that the propeller strategy can affect the collective pitch, longitudinal cyclic pitch, and the pitch attitude. If the control strategy is designed only to decrease the required power, it will result in a discontinuity in the trim characteristics. Handling qualities are investigated based on the ADS-33E-PRF requirement. The result demonstrates that the bandwidth and phase delay results and eigenvalue results in various speed at different propeller strategies are all satisfied. However, some propeller control strategies lead to severe inter-axis coupling in high-speed flight. Based on these results, this paper proposes the propeller control strategy for the coaxial compound helicopter. This strategy ensures good trim characteristics and handling qualities, which satisfy the related requirements, and improves the flight range or the performance in high-speed flight.

Investigation of Reaction Control System Design on Spacecraft Handling Qualities for Docking

2009 ◽  
Vol 32 (6) ◽  
pp. 1723-1735 ◽  
Author(s):  
Randall E. Bailey ◽  
E. Bruce Jackson ◽  
Kenneth H. Goodrich ◽  
W. Al Ragsdale ◽  
Jason Neuhaus ◽  
...  
Keyword(s):  
Control System ◽  
System Design ◽  
Control System Design ◽  
Handling Qualities ◽  
Reaction Control System
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