Catálogo de publicaciones - libros

In this chapter we describe the block backstepping approach to flight control law design. Block backstepping is a Lyapunov based technique for controller design which is particularly well suited to the rigid body control problem where the main means of control is through the moments, which is the case in most aircraft. The resulting controller has semi-global (in the state space) stabilising properties and has a moderate number of parameters that can be used for tuning. We illustrate the theory by simulations of the ADMIRE model with a block backstepping controller in demanding manoeuvres such as high-alpha flight and high-rate velocity vector rolls.

This chapter describes the development of evolutionary and deterministic global optimisation methods for the clearance of nonlinear flight control laws for highly augmented aircraft. The algorithms are applied to the problem of evaluating a nonlinear handling qualities clearance criterion for the ADMIRE benchmark model. An optimisation-based approach for computing worst-case pilot input demands is also presented. Hybrid versions of the global algorithms, incorporating local gradient-based optimisation, are shown to significantly reduce computational complexity while at the same time improving global convergence properties. The proposed approach to flight clearance is shown to have significant potential for improving both the reliability and efficiency of the current industrial flight clearance process.

In this chapter, the manoeuvring capabilities of the ADMIRE model are analyzed using qualitative methods via computation of attainable equilibrium sets, local stability maps and two-dimensional cross-sections of stability regions for stable equilibria considering the velocity-vector roll manoeuvre. A nonlinear dynamic inversion control law is implemented as a prototype of a control and stability augmentation system. The analysis of the closed-loop dynamics allows one to assign the airplane manoeuvre limitations via specification of flight envelope critical boundaries. A functional interconnect between control inputs helps to avoid control surfaces saturation and to significantly enhance the ADMIRE manoeuvrability at high angles of attack. A number of computational examples for attainable equilibrium sets and regions of attraction illustrate the applied investigation methodology.

The Industrial Evaluation task is performed as part of the GARTEUR Action Group to show industry’s view of the work presented by the universities and the research establishments involved in the group. The evaluation also contributes to the process of knowledge transfer of new technologies into industry. The objective is not to find the best method for aircraft control law design and analysis but to examine the potential of the presented methods. The purpose of the industrial evaluation is also to assess whether the presented methods can reduce the time and effort required to develop flight control systems or help to develop flight control systems with higher quality and reduced demands on on-board computer capacity.

The main objective of the Action Group was to investigate the potential benefits of nonlinear design and analysis methods for control law development in aerospace vehicles. To guarantee the industrial relevance of the project, two highly realistic simulation models were developed, together with demanding design/analysis challenges. These benchmarks in themselves represent significant achievements of the project, since there are still very few industrially relevent aircraft models, with realistic design and analysis specifications, available in the open literature on which control theoreticians can test and validate new techniques and algorithms. An additional benefit of the on-ground transport aircraft benchmark developed by Airbus for the project is that it represents a non-standard control application (at least in the context of aerospace control!) and thus adds another new and challenging set of problems to those traditionally addressed by flight control law designers.