Patent ID: 6390417
Filing Date: 2002-05-21
Classification: B64C,B64D,G05D,Y02T

Abstract:
A drag control system for a flying machine, comprising a thrust estimating means for estimating the thrust of the flying machine while flying in the air, a motion state detecting means for detecting a given motion state of the flying machine, a drag estimating means for estimating the drag of the flying machine, based on the detected motion state and the estimated thrust, a drag varying means for varying the drag of the flying machine, an operation-amount calculating means for calculating the amount of operation of the drag varying means for minimizing the estimated drag, and an operating means for operating the drag varying means, based on the calculated amount of operation,said drag estimating means comprising (a) a means for estimating the thrust T of the flying machine, (b) a means for detecting the following motion state parameters of the flying machine: &phgr;: the roll attitude angle (an Eulerian angle about an X axis); &thgr;: the pitch attitude angle (an Eulerian angle about a Y axis); U: the speed in a direction of the X axis; V: the speed in a direction of the Y axis; W: the speed in a direction of the Z axis; P: the roll angular speed (an angular speed about the X axis); Q: the pitch angular speed (an angular speed about the Y axis); R: the yaw angular speed (an angular speed about the Z axis); &agr;: the pitch angle formed by the direction of movement of the flying machine and the center line of the flying machine, (c) a means for calculating components Xa and Za of the air force in the directions of the X and Z axes applied to the flying machine by substituting the detected motion state into the following equations: Xa=mÂ·(dU/dt+QÂ·Wâˆ’RÂ·V)+mÂ·gÂ·sin &thgr;Za=mÂ·(dW/dt+PÂ·Vâˆ’QÂ·U)âˆ’mÂ·gÂ·cos &thgr;Â·cos &phgr;â€ƒwherein g is the gravitational acceleration, and m is the mass of the flying machine, (d) a means for calculating the drag D of the flying machine by substituting the estimated thrust T, the detected pitch angle &agr; and the calculated components Xa and Za of the air force in the directions of the X and Z axes into the following equation: D=(Tâˆ’Xa)Â·cos &agr;âˆ’ZaÂ·sin &agr;â€ƒwherein the operations of means (c) and (d) are carried out sequentially, after the operations of means (a) and (b) are carried out, irrespective of the order, to thereby estimate the drag of the flying machine without using a drag coefficient.