Preliminary design of advanced flight control system architectures for commercial transport aircraft

Thomas Lampl, Timo Wolf, Mirko Hornung
2018 CEAS Aeronautical Journal  
The functional enhancement of Flight Control Systems (FCS) show potential benefits for commercial transport aircraft. Furthermore, the consideration of new technologies and more-electric concepts lead to a significant increase of the design space for FCS architectures. The objective of this contribution is to enable the preliminary design of advanced FCS architectures for a given FCS configuration. Based on a comprehensive literature research, the main subsystems are identified and simplified
more » ... dels of the architecture are developed. Additionally, technological constraints as well as design rules for actuator distribution, and power redundancy are defined. The design rules for advanced FCS architectures are derived from the basic design rules of existing FCS architectures of commercial transport aircraft. Finally, the presented method is implemented into a design tool. The resulting tool enables the preliminary design of multifunctional FCS architectures. Aerospace Europe 6th CEAS Conference on aircraft system level [6, 7] . Both aspects lead to new technological constraints or additional options for the FCS architecture, which increase the design space to find valid solutions. Figure 1: Overall design method for advanced flight control systems [5]. The objective of this contribution is to enable the preliminary design of advanced FCS architectures. Therefore, simplified models of the systems of the architecture are developed. Furthermore, technological assumptions are made and design rules for actuator distribution, power redundancy, and reconfiguration are defined. The main design rules are based on a comprehensive review of existing FCS architectures of Airbus and Boeing transport aircraft. Finally, the presented method will be implemented into MATLAB ® by object-oriented programming. The resulting tool enables the preliminary design of an architecture for a given advanced FCS configuration for further analysis and sizing. BACKGROUND In this section the main requirements and constraints for Flight Control System (FCS) architectures is shown. Furthermore, the state of the art and design aspects for FCS architectures of commercial transport aircraft are presented. Finally, a brief overview on previous studies regarding FCS architecture design principles in early aircraft design phases is given. Flight Control System Requirements According to Lampl et al. [5], the FCS can be divided into a configurational system and architectural system. The FCS configuration describes the layout of the flight control devices, including the kinematics, supports, and the fairings. The flight control devices of the FCS are generally classified as primary or secondary, depending on their function and criticality. The flight-critical primary flight control devices (e.g. aileron, elevator, and rudder) are continuously activated to maintain safe attitude and trajectory control of the aircraft. Secondary flight control devices (e.g. high-lift control devices) are deployed intermittently or only during certain flight phases and thus, less critically for a safe flight. The FCS architecture, in terms of number of actuators, distribution of the power supply and Flight Control Computers (FCC), is primarily driven by safety considerations [8, 9] . The fault tolerance and fault detection are key points in the design of FCS to withstand single or multiple failures, while maintaining the necessary level of safety [1] . For example, the complete loss of power supply for the flight control actuation systems should be extremely improbable (10 -9 ). That's why a minimum of three independent power sources for the actuators of the primary flight control devices are required [10] . Dedicating standards and regulations are defined by the CS-25 of the EASA and the FAR 25 of the FAA.
doi:10.1007/s13272-018-0338-8 fatcat:27xvx42txngptfgy3f5bf7knii