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Unformatted text preview: EE 428 PROBLEM SET 3 DUE: 28 Sep 2007 Reading assignment: Ch 3 sections 3.6 through 3.8 and section 4.1. Problem 10 (25 points) The landing of an airplane consists of three phases. First, the airplane is guided by radio directionfinding equipment toward the airport with approximately the correct heading. Within a few miles of the airport, radio contact is made with the radio beam of the i nstrument l anding s ystem (ILS). The pilot follows this beam to guide the airplane along a glidepath angle γ of approximately − 3 ◦ toward the runway. Finally, at an altitude h(t) of approximately 100 ft, the ﬂareout phase of the landing begins. During this final phase of the landing, the ILS radio beam is no longer effective (because of electromagnetic disturbances), nor is the − 3 ◦ glidepath angle desirable from the viewpoint of safety and comfort. Therefore, the pilot must guide the airplane along the desired ﬂare path by making visual contact with the ground. The objective of this problem is to develop a statespace model and allintegrator blockdiagram of the airplane for the final phase of the landing (the last 100 ft of the airplane’s descent). The airplane is guided to the proper location by air traﬃc control. The altitude h(t) and rate of ascent dh/dt at the beginning of this ﬂareout phase range from 80 to 120 ft and from 16 to 24 ft/sec, respectively. The airplane is wavedoff for values outside this range. Finally, only the longitudinal motion (that is, the motion in a vertical plane) is of interest in the final landing phase. Lateral motion of the airplane is required primarily to point the airplane down the runway, and is accomplished prior to the final ﬂareout phase of the landing. The first step in the development of the statespace model and design of the landing control system is the formulation of the equations of motion of the airplane. The coordinates and angles of the airplane are depicted in Figure 1 and the symbols are defined in Table 1. The formulation of the equations of motion begins with a consideration of the aerodynamic forces and moments and the application of the fundamental laws of mechanics. The assumption that the deviation from the equilibrium ﬂight condition is small is then utilized to linearize the resulting equations. Because of the landing geometry, the glidepath angle γ is suﬃciently small so that the small angle approximations sin γ ≈ γ and cos γ ≈ 1 can be made. Finally, the assumption is made that the velocity V of the airplane is maintained essentially constant during the landing by utilizing throttle control. Thus, the longitudinal motion of the aircraft is controlled entirely by the elevator deﬂection δ (t)....
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This note was uploaded on 07/23/2008 for the course EE 428 taught by Professor Schiano during the Fall '07 term at Penn State.
 Fall '07
 SCHIANO

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