An analytical procedure is presented, which is able to estimate the accuracy of geostationary orbit determination as a function of the locations of tracking stations and the amount and noise-level of tracking data. On the assumption of linearized two-body orbital motion, satellite position/velocity error and station-keeping error are evaluated by covariance analysis. Examples of the accuracy estimation are shown for the cases of ranging and angle tracking, with the station location being varied as a parameter.
A synthesis of reduced-order compensators for active flutter suppression of a two-dimensional airfoil is studied using the optimal projection method. In the method, condition for minimizing a quadratic performance index is taken into consideration for a compensator whose the order is less than the order of the controlled plant. A reduced-order compensator is then constructed by satisfying the condition. In this paper, rough derivation of two modified Riccati equations and two modified Lyapunov equations as the condition are shown. Since these equations are coupled each other, it is not possible to solve them at one time. Therefore, iterative calculation methods are examined and an algorithm which improves a defect of the existing iterative method is proposed. Numerical simulations which are carried out using thirteenth-order active flutter suppression systems of a two-dimensional airfoil show that the optimal projection method can yield second-order compensators in all simulation cases, and compensators whose the order is six or more almost show the same control performance as the optimal observer, that is, Kalman filter.
This paper presents an analysis, in the framework of the classical theory of plates, on the pure bending deformation produced in the four points bending tests of symmetric crossplies of fiber reinforced composites. The aim of the analysis is to establish conditions on the test specimens and devices to realize the pure bending deformation at least in a central portion of the specimens. Exact solutions by way of trigonometric series expansion are obtained for an idealized model; a rectangular plate subject to a uniformly distributed moment along a pair of parallel ends whose deflection is constrained. Numerical solutions are calculated by finite element method for four types of model subjected to concentrated loads simulating the actual loading mechanisms. The results show that the pure bending deformation depends not only on the laminates composition but also on the length of the specimen, the span between the loading cylinders and the span between the supporting cylinders of the test device as the ratios to the specimen breadth.
In this paper, the synthesis of nonlinear flight control system for an aircraft to track a given trajectory is presented. The trajectory is given in the form of position in space, which is the functions of time or the tangent velocity and the two path angles which are computed from the differentiation of the position with respect to time. The forces which guide the airplane along the given trajectory are basically constracted of two parts. One is the force necessary for the program motion and the other is the force to eliminate the guidance errors. The algorithm of this controller was applied to F-4 fighter performing a barrel roll maneuver and some numerical simulations were performed. The results showed that the differences between the actual flight path and the given one were negligible.
The author has considerable interest in the range performance of WIG (Wing-in-Ground) effect vehicles. There are two opposite effects concerning this problem. The favorable one is well-known reduction in the induced drag due to ground proximity. Whilst the unfavorable is no utilisation of reduction in the specific-fuel-consumption of gas-turbine-engine at high altitude. Simple calculations show that WIG is suitable for shorthaul operation, say 1, 000km, than long range, say 10, 000km. Merits and demerits of changing the geometric-wing-aspect-ratio or flight dynamic pressure are discussed.