JP2005326172A - Optical inclination measuring method and optical inclination sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect an absolute degree of inclination of an object such as a model airplane to the ground by use of an inexpensive device. <P>SOLUTION: An optical sensor is attached to a predetermined object, and the position of the sun to the object is geometrically calculated by use of the optical sensor and taken as a first parameter vector. A reference axis is provided to the object and taken as a second parameter vector. The position of the sun to the ground is taken as a third parameter vector, and the position of the reference axis to the ground is taken as a fourth parameter vector. The correlation between the first parameter vector and the third parameter vector and the correlation between the second parameter vector and the fourth parameter vector are derived, and the absolute degree of inclination of the object to the ground is derived based on the first parameter vector to the fourth parameter vector and the correlations. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical tilt measurement method and an optical tilt sensor.

  In maneuvering a model aircraft, it is important to maintain the attitude of the aircraft. Conventionally, an operator has read the inclination and hit the rudder against disturbance caused by wind. This method eventually corrects the inclination of the attitude of the aircraft due to disturbance by the operator's visual observation, but when the aircraft is far away, the visual observation itself becomes very difficult, and The operation amount may be excessive or insufficient, or the operation may be delayed.

  On the other hand, there is a method in which a conventional gyro sensor is used to detect a disturbance with respect to a tilt, and the rudder is automatically operated in a direction to cancel the instantaneous external force. This method is effective for instantaneous tilt disturbance, but the gyro sensor detects angular acceleration, that is, external force to rotate, and how much it tilts by integrating this twice. Although the rotation angle can be detected, its accuracy is extremely low. Furthermore, there is a drawback that errors are accumulated for slow (low frequency) disturbances and do not function effectively. In view of such a problem, use of an optical fiber gyroscope, a ring laser gyroscope, or the like has also been studied. However, these are very expensive and are not suitable as a general model aircraft sensor.

  An object of the present invention is to detect the absolute inclination of an object such as a model airplane with respect to the ground using an inexpensive device.

In order to achieve the above object, the present invention provides:
Attaching an optical sensor to a predetermined object;
Using the optical sensor to geometrically calculate the position of the sun with respect to the object, to provide a first parameter vector;
Providing a reference axis for the object to provide a second parameter vector;
Setting the position of the sun relative to the ground as a third parameter vector;
Setting the position of the reference axis with respect to the ground as a fourth parameter vector;
Deriving a correlation between the first parameter vector and the third parameter vector, and a correlation between the second parameter vector and the fourth parameter vector;
Deriving an absolute inclination degree of the object with respect to the ground based on the fourth parameter vector and the correlation from the first parameter vector;
It is related with the optical inclination measuring method characterized by comprising.

The present invention also provides:
An optical sensor attached to a predetermined object for geometrically calculating the position of the sun relative to said object as a first parameter vector;
Reference axis defining means for defining a reference axis for the object;
The present invention relates to an optical tilt sensor.

  The present inventors provide an optical sensor and a reference axis defining means for an object whose degree of inclination is to be measured, derive the position of the sun and the reference axis with respect to the object, respectively, and further detect the sun and the reference position with a predetermined position detecting means. The position of the reference axis with respect to the ground was derived, and the absolute inclination of the object with respect to the ground was successfully measured by a completely new method using these correlations.

  According to the present invention, since an expensive gyro sensor as in the prior art is not used, the absolute inclination of an object such as a model airplane can be detected in real time based on the derivation.

  The details of the present invention and other features and advantages will be described in detail below based on the best mode.

  FIG. 1 is an exploded configuration diagram showing a preferred embodiment of an optical sensor used in the optical tilt sensor of the present invention. The optical sensor 10 shown in FIG. 1 includes a two-dimensional position detector 11, a cover 12 having a pinhole 12 </ b> A provided thereabove, and a detector 11 between the detector 11 and the cover 12 with a convex portion downward. And a hemispherical lens 13 provided so as to be in contact with the upper surface. An optical sensor 10 shown in FIG. 1 is attached to an object whose inclination is to be measured, and is used for geometrically calculating the position of the sun with respect to the object.

  Specifically, sunlight is taken in through the pinhole 12A in the cover 12, received by the two-dimensional position detector 11, and the azimuth angle and elevation angle of the sunlight with respect to the two-dimensional light receiving position are derived. The position of the sun with respect to the object is calculated geometrically.

  The hemispherical lens 13 is not necessarily required in the present invention, but when the incident angle (elevation angle) θ of sunlight with respect to the optical sensor 10 is small, as shown in FIG. If it does not exist, the sunlight cannot be received by the two-dimensional position detector 11, and as a result, the position of the sun relative to the object cannot be calculated geometrically.

  On the other hand, as shown in FIG. 2B, in the case where the hemispherical lens 13 is present, even when the incident angle θ of the sunlight is sufficiently small, due to the effect of refraction by the hemispherical lens 13 of the sunlight, After passing through the hemispherical lens 13, the sunlight is refracted downward, so that the sunlight can be received by the two-dimensional position detector 11. As a result, the position of the sunlight with respect to the object can be calculated geometrically.

  Next, a method for geometrically calculating the solar position using the optical sensor 10 shown in FIG. 1 will be described. FIG. 3 is a diagram for explaining a method of deriving the azimuth angle ψ of the sun with respect to the object using the optical sensor 10 shown in FIG. FIG. 3 shows the optical sensor 10 as viewed from above. Further, the azimuth angle ψ is defined with respect to XY coordinates orthogonal to each other about the pinhole 12A of the optical sensor 10.

なる関係式で表すことができる。 When the azimuth angle ψ and the detection position (x, y) of sunlight in the two-dimensional position detector 11 are in a relationship as shown in FIGS. 3A and 3D, the azimuth angle ψ and the detection position (x , Y)

It can be expressed by the following relational expression.

なる関係式で表すことができる。 On the other hand, when the azimuth angle ψ and the detection position (x, y) of sunlight in the two-dimensional position detector 11 are in a relationship as shown in FIGS. 3B and 3C, the azimuth angle ψ and the detection position (X, y) is

It can be expressed by the following relational expression.

なる関係式で表すことができる。ここで、ｈは半球レンズ１３の厚さであり、ｎ１は大気（空気）中の屈折率であり、ｎ２は半球レンズ１３の屈折率であり、ｒ＝（ｘ^２＋ｙ^２）^１／２である。 FIG. 4 is a diagram for explaining a method of deriving the elevation angle θ of the sun with respect to the object using the optical sensor 10 shown in FIG. FIG. 4 shows the optical sensor 10 as viewed from the side. As shown in FIG. 4, when sunlight enters the optical sensor 10 at an elevation angle θ and is received at the detection position (x, y) by the two-dimensional position detector 11, the elevation angle θ is

It can be expressed by the following relational expression. Here, h is the thickness of the hemispherical lens 13, n1 is the refractive index in the atmosphere (air), n2 is the refractive index of the hemispherical lens 13, and r = (x ² + y ² ) ^1/2 is there.

を導出することができる。 Thus, the position of the sun relative to the object is defined by the azimuth angle ψ and the elevation angle θ, and the sun vector (first parameter vector) relative to the object.

Can be derived.

  The optical tilt sensor of the present invention includes reference axis defining means in addition to the optical sensor shown in FIG. This reference axis defining means is attached to the object in the same manner as the optical sensor 10, and sets a reference axis for the object. The reference axis defining means can be composed of, for example, an acceleration sensor. In this case, the reference axis defines the direction of gravity acceleration with respect to the object. Further, the reference axis defining means can be constituted by, for example, a geomagnetic sensor. In this case, the reference axis defines the polar direction with respect to the object.

  A general-purpose sensor can be used as the acceleration sensor and the geomagnetic sensor.

を導出することができる。 Thus, by providing a reference axis defining means such as an acceleration sensor or a geomagnetic sensor for the object, a reference axis (second parameter vector) such as the direction of gravitational acceleration or the polar direction with respect to the object.

Can be derived.

とし、前記参照軸の位置ベクトル（第４のパラメータベクトル）を

として、前記物体の、前記座標系ＸＹＺにおける各軸回りの回転角度をα、β、γとすると、前記第１のパラメータベクトル及び前記第３のパラメータベクトル、並びに前記第２のパラメータベクトル及び前記第４のパラメータベクトルの間には、

なる関係式が成立する。なお、Ｒは回転行列であり、

なる関係式が成立する。 On the other hand, the sun position vector (third parameter vector) in the coordinate system XYZ based on the ground

And the reference axis position vector (fourth parameter vector)

Assuming that the rotation angles of the object around the respective axes in the coordinate system XYZ are α, β, and γ, the first parameter vector, the third parameter vector, the second parameter vector, and the second parameter vector Between the four parameter vectors,

The following relational expression holds. R is a rotation matrix,

The following relational expression holds.

なる関係式が成立し、これより、回転行列Ｒは、

なる関係式で算出することができる。 In addition, when the first parameter vector and the second parameter vector do not overlap each other and the second parameter vector is invariant, considering an outer product vector (Equation I) of these parameter vectors,

From this, the rotation matrix R is

It can be calculated by the following relational expression.

In this case, since the first parameter vector (E equation) to the fourth parameter vector (H equation) and the outer product vector (I equation) are known, the rotation matrix R can be calculated from equation (8). As a result, the rotation angles α, β, γ around the respective axes in the coordinate system XYZ provided on the ground of the object can be calculated by the following relational expressions.

  Therefore, the absolute inclination degree of the object with respect to the ground can be derived from the rotation angle of the object around each axis of the coordinate system XYZ, that is, the equations (9) to (11). .

  As described above, the present invention has been described in detail based on the embodiments of the present invention with specific examples. However, the present invention is not limited to the above contents, and all modifications and changes are made without departing from the scope of the present invention. It can be changed.

  The present invention can be suitably used as an inclination / orientation sensor that can be used for attitude control and automatic navigation of model aircraft and unmanned robots.

It is a disassembled block diagram which shows the preferable aspect of the optical sensor used for the optical inclination sensor of this invention. It is a figure which shows the difference in the incident state of sunlight by the presence or absence of a hemispherical lens. It is a figure for demonstrating the method to derive | lead-out the azimuth | direction angle (psi) of the sun with respect to an object using the optical sensor shown in FIG. It is a figure for demonstrating the method to derive | lead-out the elevation angle (theta) of the sun with respect to an object using the optical sensor shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical sensor 11 Two-dimensional position detector 12 Cover 12A Pinhole 13 Hemispherical lens

Claims (21)

Attaching an optical sensor to a predetermined object;
Using the optical sensor to geometrically calculate the position of the sun with respect to the object, to provide a first parameter vector;
Providing a reference axis for the object to provide a second parameter vector;
Setting the position of the sun relative to the ground as a third parameter vector;
Setting the position of the reference axis with respect to the ground as a fourth parameter vector;
Deriving a correlation between the first parameter vector and the third parameter vector, and a correlation between the second parameter vector and the fourth parameter vector;
Deriving an absolute inclination degree of the object with respect to the ground based on the fourth parameter vector and the correlation from the first parameter vector;
An optical tilt measuring method comprising:   2. The optical tilt measurement according to claim 1, wherein the optical sensor includes a two-dimensional position detector and a cover having a predetermined pinhole provided on the two-dimensional position detector. Method.   The optical sensor includes a hemispherical lens provided with a convex surface downward between the two-dimensional position detector and the cover so as to receive sunlight incident on the optical sensor at a low angle. The optical tilt measuring method according to claim 2, wherein the optical tilt measuring method is performed.   The geometric calculation of the position of the sun by the optical sensor is performed based on an azimuth angle ψ and an elevation angle θ of sunlight with respect to the optical sensor, according to any one of claims 1 to 3. Optical tilt measurement method.   The optical tilt measurement method according to claim 1, wherein the reference axis is a direction of gravitational acceleration by an acceleration sensor attached to the object.   The optical tilt measurement method according to claim 1, wherein the reference axis is a polar direction by a geomagnetic sensor attached to the object.   The correlation between the first parameter vector and the third parameter vector and the correlation between the second parameter vector and the fourth parameter vector are based on a rotation matrix of the optical sensor in a predetermined coordinate axis with respect to the ground. The optical tilt measurement method according to claim 1, wherein the optical tilt measurement method is characterized.   The optical inclination measurement method according to claim 7, wherein the absolute inclination degree of the object with respect to the ground is defined by rotation angles α, β, and γ around the respective axes of the coordinate axes. The rotation matrix

, The rotation angles α, β and γ representing the degree of inclination of the object are as follows:

The optical tilt measurement method according to claim 8, wherein: An optical sensor attached to a predetermined object for geometrically calculating the position of the sun relative to said object as a first parameter vector;
Reference axis defining means for defining a reference axis for the object;
An optical tilt sensor characterized by comprising:   The optical tilt sensor according to claim 10, wherein the optical sensor comprises a two-dimensional position detector and a cover having a predetermined pinhole provided on the two-dimensional position detector. .   The optical sensor includes a hemispherical lens provided with a convex surface downward between the two-dimensional position detector and the cover so as to receive sunlight incident on the optical sensor at a low angle. The optical tilt sensor according to claim 11, wherein   The geometric calculation of the position of the sun by the optical sensor is performed based on an azimuth angle ψ and an elevation angle θ of sunlight with respect to the optical sensor, according to any one of claims 10 to 12, Optical tilt sensor.   The reference axis defining means is an acceleration sensor attached to the object and for deriving a direction of gravitational acceleration as a reference axis in the object. Optical tilt sensor.   The optical according to any one of claims 10 to 13, wherein the reference axis defining means is a geomagnetic sensor attached to the object and for deriving a polar direction as a reference axis in the object. Tilt sensor.   The optical inclination sensor according to any one of claims 10 to 15, further comprising sun position detecting means for deriving the position of the sun with respect to the ground as a third parameter vector.   The optical tilt sensor according to any one of claims 10 to 16, further comprising reference axis detection means for deriving a position of the reference axis with respect to the ground as a fourth parameter vector.   Deriving a correlation between the first parameter vector and the third parameter vector, and a correlation between the second parameter vector and the fourth parameter vector, and from the first parameter vector, the fourth parameter vector, And an optical tilt sensor comprising a calculation means for deriving an absolute tilt degree of the object with respect to the ground based on the correlation.   The correlation between the first parameter vector and the third parameter vector and the correlation between the second parameter vector and the fourth parameter vector are based on a rotation matrix of the optical sensor in a predetermined coordinate axis with respect to the ground. 19. An optical tilt sensor according to claim 18, characterized in that   The optical inclination sensor according to claim 19, wherein the absolute inclination degree of the object with respect to the ground is defined by rotation angles α, β, and γ around the respective axes of the coordinate axes. The rotation matrix

, The rotation angles α, β and γ representing the degree of inclination of the object are as follows:

The optical tilt sensor according to claim 20, wherein

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