New methodology for flight control system sizing and hinge moment estimation

Flight control surfaces guarantee a safe and precise control of the aircraft. As a result, hinge moments are generated. These moments need to be estimated in order to properly size the aircraft actuators. Control surfaces include the ailerons, rudder, elevator, flaps, slats, and spoilers, and they are moved by electric or hydraulic actuators. Actuator sizing is the key when comparing different flight control system architectures. This fact becomes even more important when developing more-electric aircraft. Hinge moments need to be estimated so that the actuators can be properly sized and their effects on the overall aircraft design are measured. Hinge moments are difficult to estimate on the early stages of the design process due to the large number of required input. Detailed information about the airfoil, wing surfaces, control surfaces, and actuators is needed but yet not known on early design phases. The objective of this paper is to propose a new methodology for flight control system sizing, including mass and power estimation. A surrogate model for the hinge moment estimation is also proposed and used. The main advantage of this new methodology is that all the components and actuators can be properly sized instead of just having overall system results. The whole system can now be sized more in detail during the preliminary design process, which allows to have a more reliable estimation and to perform systems installation analysis. Results show a reliable system mass estimation similar to the results obtained with other known methods and also providing the weight for each component individually.

Intelligent Fault-Tolerant Control for AC/DC Hybrid Power System of More Electric Aircraft

This paper presents a novel intelligent fault-tolerant control method for a kind of more electric aircraft AC/DC hybrid electrical power system, in order to ensure the safe operation of the engine and improve the power supply quality. The more electric aircraft electrical power system was combined with an aircraft engine, two generators, two AC/DC rectifiers, two DC/AC inverters, DC loads, and AC loads. A multi-objective optimization intelligent sliding mode fault-tolerant controller was obtained for aircraft engine with actuator faults. Each of AC/DC rectifiers is 12-pulse autotransformer rectifier unit with active power filter. Active power filter was used to realize the desired performance of DC bus. Intelligent fractional order PI controller is presented for AC/DC rectifier by considering multiple performance indexes. In order to guarantee the AC-side has satisfying voltage, current, and frequency, no matter the sudden change of AC load that happens or DC/AC fault that occurs, the virtual synchronous generator control method was used for DC/AC inverters. Simulation results verify the effective of the proposed more electric aircraft AC/DC hybrid electrical power system.

Commercial Aircraft Electrification—Current State and Future Scope

Electric and hybrid-electric aircraft propulsion are rapidly revolutionising mobility technologies. Air travel has become a major focus point with respect to reducing greenhouse gas emissions. The electrification of aircraft components can bring several benefits such as reduced mass, environmental impact, fuel consumption, increased reliability and quicker failure resolution. Propulsion, actuation and power generation are the three key areas of focus in more electric aircraft technologies, due to the increasing demand for power-dense, efficient and fault-tolerant flight components. The necessity of having environmentally friendly aircraft systems has promoted the aerospace industry to use electrically powered drive systems, rather than the conventional mechanical, pneumatic or hydraulic systems. In this context, this paper reviews the current state of art and future advances in more electric technologies, in conjunction with a number of industrially relevant discussions. In this study, a permanent magnet motor was identified as the most efficient machine for aircraft subsystems. It is found to be 78% and 60% more power dense than switch-reluctant and induction machines. Several development methods to close the gap between existing and future design were also analysed, including the embedded cooling system, high-thermal-conductivity insulation materials, thin-gauge and high-strength electrical steel and integrated motor drive topology.