Design of Control Systems to Hold Altitude and Heading in Severe Atmospheric Disturbances for an Unmanned Airplane

Abstract

The objective of the present work is to design the control systems required to hold altitude and heading in severe atmospheric disturbances in cruise flight for the Unmanned Airplane for Ecological Conservation using modern control design techniques. The airplane mathematical model in open-loop was defined by the linearized longitudinal and lateraldirectional equations of motion. Different control systems were designed based on modern control design techniques. These are the eigenstructure assignment or polo-placement technique, linear quadratic design with full state feedback, and linear quadratic Gaussian design. To verify the design of control systems, simulations of the open-loop and closed-loop systems were performed, and each control system was tested. The atmospheric disturbances considered were the gust disturbance, which was idealized by the one-minus-cosine gust profile, and the atmospheric turbulence, which was modeled by Dryden's function. The control systems designed to hold in-flight altitude and heading achieved their purpose. In any simulation, the maximum load factor, the stall speed and the maximum dive speed were not achieved. Nomenclature A, B, C = state, control, and gust disturbance matrices a = coefficients of open-loop plant matrix characteristic equation a = coefficients of desired closed-loop characteristic equation d = gust diameter g = constant vector H = flight altitude K= feedback gain L k = steady-state Kalman gain L T = correlation length of turbulence n y , n z = load factors in y and z axes Q, R = weighting matrices for linear quadratic regulator problem Q n , R n = weighting matrices in the algebraic filter Riccati equation P = Riccati matrix p, q, r = roll, pitch, and yaw rates p g , q g , r g = rotary gust velocities about x, y, and z axes t = time u, v, w = longitudinal, lateral and vertical components of velocity u e , v e , w e = longitudinal, lateral and vertical components of gust velocity respect to earth axes u g , v g , w g = longitudinal, lateral and vertical components of gust velocity respect to wind airframe axes u o = initial forward speed v go , w go = maximum lateral and vertical gust velocities w A , w B = weighting factors

Simultaneous small UAV and autopilot system design

“…From these figures, it can be seen that qualitative behaviors of flight dynamics modes are similar with the ones given in Zagi website, and as in Hajiyev (2008, 2013), Cardenas et al (2012) and Jeni and Budiyono (2006).…”

Integrated Structural, Flight Dynamics and Aeroelastic Analysis of the ANCE X-3d as a Flexible Body

“…6 This software calculates the critical load factors at asymmetric flight conditions considering the maximum deflection of the control surfaces for each individual component, which is ±15 deg. 7 Open-loop simulations were carried out to obtain the maximum load factor values using the corresponding flight parameters of each flight condition. Flight envelope diagrams at sea level and for cruise altitude are drawn based on the data attained by these simulations according to the FAR Part 23 (Ref.…”

Dynamic Ground Effect on the Longitudinal Stability of Airplanes during the Landing

“…A program to perform flight simulations 13 Table A2 were used to create interpolated functions, which are used for the program to obtain the stability coefficients at each altitude. When the altitude changes during a simulation, the program estimates anew the stability derivatives using the corresponding stability coefficients, air density and wind speed.…”

“…When the altitude changes during a simulation, the program estimates anew the stability derivatives using the corresponding stability coefficients, air density and wind speed. 13 Simulations were performed placing ten heights above ground as starting point, with initial speed of 32.0208 m/s (1.3 of stall speed) and time step of 0.015 s. The airplane model was perturbed by elevator deflection of 5 deg step function during 0.2 s in each simulation. Figure 4 illustrates the airplane height above ground in time-domain; the starting heights are shown in the captions.…”