Portal de Periódicos da CAPES

Flexible vehicle control using quantitative feedback theory

1995; American Institute of Aeronautics and Astronautics; Volume: 18; Issue: 5 Linguagem: Inglês

10.2514/3.21505

1533-3884

R. A. Hess, Dennis Henderson,

Adaptive Control of Nonlinear Systems

The design of a longitudinal pitch-axis flight control system for a flexible aircraft with uncertainty in the vehicle model is presented. This uncertainty includes the characteristics of the vehicle elastic mode. Quantitative feedback theory is used in the control system design. A level 1 handling qualities requirement is included in the control systems design specifications. This requirement is generated through pilot-vehicle analysis using a structural model of the human pilot and handling qualities sensitivity functions. Although two aerodynamic controls were available (elevator and forward vane), it is shown that elevator control alone can be used to meet the command-following, disturbance rejection, and handling qualities requirements. Nomenclature [d®/dx]cp = slope of body bending mode shape evaluated at pilot's station q = dO/dt, rad/s u = perturbation of x body axis component of vehicle velocity, ft/s a = angle of attack, rad 8C = canard angle (positive trailing edge down), deg 8e = elevator angle (positive trailing edge down), deg rj = generalized modal coordinate for symmetric body bending mode 9 = pitch attitude of rigid body, rad