Design and experimental evaluation of a fuzzy logic pressure controller for the Airbus 310/320 braking control system P.J. Costa Branco n , J.A. Dente Instituto Superior Te´cnico (IST), CIEEE, Av. Rovisco Pais 1096-011, Lisboa Codex, Portugal article info Article history: Received 21 April 2009 Accepted 31 December 2009 Available online 9 February 2010 Keywords: Fuzzy control Aerospace applications Fuzzy logic Braking systems abstract We show here the design and preliminary experimental evaluation steps of a fuzzy controller for the pressure loop of a proposed new Airbus A310/A320 modular braking system. The results indicated that two main requirements of this system could be achieved:  pressure control with high robustness in the case of hydraulic load fluctuations, and;  highly modular characteristics, since the same fuzzy controller can be used in both aircraft by doing only a simplified tuning of one of its gain parameters. & 2010 Elsevier Ltd. All rights reserved. 1. Introduction Aircraft braking systems (Kroes et al., 1993) run all their functions, for example pressure control, diagnostics and antiskid, in a central unit, as shown in Fig. 1. However, this structure means that the braking system with its central control unit is handling an ever increasing number of elements, becoming extremely complex and difficult to analyze for control purposes, and being aircraft specific (Murphy et al., 2006; Tunay et al., 2001). On the other hand a modular structure (Reznik et al., 2000; Al-Garni et al., 2006), as shown in Fig. 2, in which the braking functions of pressure and antiskid control run locally and independently introduces several benefits to actual aircraft braking systems. They are that:  it can be reusable since the same pressure module can be used in different aircraft;  it represents an improvement in the braking system security since it deals with local controllers and,  the modular structure will significantly reduce the braking system’s weight of the aircraft. In this paper, we describe the preliminary design and evalua- tion of a fuzzy logic pressure controller for future modular Airbus 310/320 braking systems. Two main requirements are expected to be fulfilled by the fuzzy controller:  low sensitivity to possible disturbances and changes of hydraulic brake parameters, and; simplified controller tuning easier to adapt for use in different aircraft. Our approach had been to develop the fuzzy controller by using the already developed models of the A310 and A320 braking systems. The simulation studies that had been performed for these models allowed us to verify the fuzzy controller sensitivity to possible uncertainties in the hydraulic brake as well as the controller tuning in view of its use in different aircraft. The feasibility of the fuzzy pressure controller designed in this anterior simulation study was evaluated: it was tested in an experimental setup with an A320 braking system. The controller was implemented in a fuzzy inference board which was connected in a microcomputer together with a data acquisition card. A series of experimental tests had been executed to verify the controller’s performance for particular situations that are relevant for the aircraft’s braking system behavior. These results revealed the potential benefits of using a fuzzy logic pressure controller for the new modular structure, but also revealed some drawbacks leading us to correct the initial fuzzy controller and eventually to even redesign a new one. ARTICLE IN PRESS Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/engappai Engineering Applications of Artificial Intelligence 0952-1976/$ - see front matter & 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.engappai.2009.12.008 n Corresponding author. Tel.: + 351 21 8417432. E-mail address: pbranco@ist.utl.pt (P.J. Costa Branco). Engineering Applications of Artificial Intelligence 23 (2010) 989–999