초록 ▼

An arithmetic processing method and system in a wide velocity range flight velocity vector measurement system using a square truncated pyramid-shape five-hole Pitot probe. Approximation equations that determine attack angle .alpha. and sideslip angle .beta. in the form of third-order equations conce

An arithmetic processing method and system in a wide velocity range flight velocity vector measurement system using a square truncated pyramid-shape five-hole Pitot probe. Approximation equations that determine attack angle .alpha. and sideslip angle .beta. in the form of third-order equations concerning attack angle pressure coefficient C.alpha. and sideslip angle pressure coefficient C.beta., which are known numbers, are expressed in the form of a polynomial equation concerning Mach number M, where the coefficients are obtained from a lookup table. Coefficient calculations in the polynomial equation, and attack angle a and sideslip angle .beta., calculations may be performed as simple calculations by specifying and applying known numbers into the approximation equation without solving third-order equations, with calibration coefficients that form the basis of coefficient calculation with the polynomial equation first being stored in memory in advance as a table for each wide velocity range on the basis of wind tunnel testing. A Mach number may be calculated instantly from a lookup table by specifying Mach pressure coefficient CM and angle to airflow pressure coefficient C.gamma.. Wide velocity range flight velocity vector measurement with a high update rate which is capable of real time response in flight control as demanded by aircraft is obtained.

대표청구항 ▼

1. A method for arithmetically processing flight velocity vector measurement values carried out in a wide velocity range flight velocity vector measurement system that uses a square truncated triangle-shape five-hole Pitot probe, comprising the steps of:obtaining, by arithmetic processing, airflow a

1. A method for arithmetically processing flight velocity vector measurement values carried out in a wide velocity range flight velocity vector measurement system that uses a square truncated triangle-shape five-hole Pitot probe, comprising the steps of:obtaining, by arithmetic processing, airflow attack angle coefficient C.alpha., which is obtainable from five items of pressure information detected by said five-hole probe by nondimensionalizing a pressure difference of vertical pressure holes by total pressure, airflow sideslip angle pressure coefficient C.beta., which is obtainable by nondimensionalizing a pressure difference of horizontal pressure holes by total pressure, angle to airflow pressure coefficient C.gamma., which is the square root of the sum of the respective squares of said C.alpha. and C.beta., and Mach pressure coefficient CM, which is obtained by nondimensionalizing, by total pressure, a pressure difference between said total pressure and a average pressure of four holes in a square truncated pyramid surfaces; determining the current Mach number M by applying, into a Mach number calculation lookup table that stores in advance in an arithmetic processor Mach numbers M corresponding to planar coordinates of angle to airflow pressure coefficient C.gamma. and mach pressure coefficient CM over a wide velocity range, said calculated C.gamma. value and calculated CM value; and determining arithmetically attack angle .alpha. and sideslip angle .beta. by applying said calculated C.alpha. value and calculated C.beta. value and pressure calibration coefficients stored in advance in said arithmetic processor into a high-order approximation equation concerning attack angle pressure coefficient C.alpha. that determines attack angle .alpha. and a high-order approximation equation concerning sideslip angle pressure coefficient C.beta. that determines sideslip angle .beta..