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Fly-by-wire
Published in D.A. Bradley, N.C. Burd, D. Dawson, A.J. Loader, Mechatronics, 2018
D.A. Bradley, N.C. Burd, D. Dawson, A.J. Loader
A demanding application of a microprocessor system is the flight control of an aircraft. The numerous control surfaces of the aircraft, such as its ailerons and rudders, must be controlled in response to the pilot’s demand within the allowed flight envelope of the aircraft, which ensures stable flying conditions. The use of microprocessors and digital control techniques is not common among conventional aircraft owing to the high reliability requirements of the control system. However, older generations of microprocessor devices now yield reliability data which allows the necessary degrees of confidence to be met for systems in which they are used. Typically, the reliability level of the microprocessor system must be equal to or better than that of the mechanical system that it replaces, which is generally quoted as 10−7 per hour total system loss probability, or one chance in ten million.
Introduction
Published in Sergey E. Lyshevski, and Applied Mechatronics, 2018
As an example of the application of the mechatronic concept, consider the motion control problem as applied to advanced aircraft. The aircraft is controlled by flight control surfaces (aileron, canard, elevator, flap, rudder, stabilizer), and direct-drive servo-systems are used to actuate (displace) these control surfaces. A fly-by-wire control surface servo with stepper motor is illustrated in Figure 1.3. The desired angular displacement of the control surface (reference input) is assigned either by the pilot or aircraft flight computer. Using this reference signal (the specified angular displacement of the control surface), as well as the measured by sensors currents in the ab phase windings ias and bs, mechanical angular velocity ωrm and actual mechanical angular displacement of the control surface θrm, the controller develops signal-level signals that drive high-frequency switches, and the magnitude and frequency of the applied voltages to the ab phase windings uas and ubs of the permanent-magnet stepper motor are controlled by the PWM driver (amplifier) (see Figure 1.3).
Safety Management in Airlines
Published in Erik Hollnagel, David D. Woods, Nancy Leveson, Resilience Engineering, 2017
Another source of data consists of the on-board recording systems in the aircraft that collect massive amount of data. The flight data recorders (the ‘black boxes’) record flight parameters such as speed, altitude, aircraft roll, flight control inputs etc. The aircraft maintenance recorders register system pressures, temperatures, valve positions, operating modes etc. The flight data and maintenance recordings are automatically examined after each flight to check if parameters were exceeded. This is done with algorithms that check, e.g., for an approach to land with idle power. This is done by combining parameters. Making these algorithms, which are aircraft specific, is a specialised job.
Hyperloop transport technology assessment and system analysis
Published in Transportation Planning and Technology, 2020
Existing systems for high-speed long-distance passenger transport are commercially operated airlines and high-speed railways. Although the top speed of commercial passenger aircraft is around 900 km/h, the scheduled operating speed of airlines over distances of 400–1000 km between airports is only around 400–500 km/h due to time losses for taxiing, climbing, queuing and landing. High-speed railway trains have demonstrated maximum speeds up to 575 km/h in test runs, but the commercial operating speed of high-speed railway lines ranges between 150 and 300 km/h depending on the mean distance between stations and maximum design speed of the routes and rolling stock (Table 1). The Transrapid Maglev technology with electromagnetic support was originally developed in Germany for a design speed of 500 km/h, but reached only a maximum speed of 420 km/h on the short commercially operated 30 km airport link in Shanghai.
Hybrid Human Error Assessment Approach for Critical Aircraft Maintenance Practice in the Training Aircraft
Published in The International Journal of Aerospace Psychology, 2022
Ebru Yazgan, Elif Kılıç Delice
The elevator is a component of primary flight controls that are needed to securely control an aircraft during flight. These controls consist of ailerons, elevators (or, in some installations, a stabilator), and rudder, as shown in Figure 2. Movement of any of the primary flight controls makes the aircraft turn about the axis of rotation associated with the control surface. The ailerons control motion around the longitudinal axis (roll), the elevator controls rotation around the lateral axis (pitch), and the rudder controls movement around the vertical axis (yaw; Skybary, 2017). In addition, movement of any of the three primary flight control surfaces (ailerons, elevator or stabilator, or rudder), changes the air flow and pressure distribution over and around the air foil. These changes influence the lift and drag produced by the wing and control surface combination, and allow a pilot to control the aircraft about its three axes of rotation (Federal Aviation Administration, 2016). The main pitch, elevator control movement, is bringing the nose of the aircraft up or down relative to the tail. Thus, the aircraft can gain and lose altitude. If the nose is down, the aircraft is gliding or descending; if the nose is up, climbing occurs. Figure 3 gives an illustration of the elevator control system from the aircraft maintenance manual (AMM) of a Cessna 172 type training aircraft. As stated in the AMM, the elevators are operated by power transmitted through forward and aft movement of the control yoke. This movement goes to the elevators through a system that has a push–pull tube, cables, and bell cranks. The elevator control cables, at their aft ends, are attached directly to a bell crank that is installed between the elevators. This bell crank connects the elevators, and is a bearing point for the travel stop bolts. A trim tab is installed on the right elevator (CESSNA Aircraft Company, 2007). The Cessna 172 Series aircraft type weighing less than 5,700 kg, as shown in Figure 2, is a four-seat, single-engine, high-wing and fixed-wing aircraft, the most produced and popular training aircraft in the world.