JPH0349366B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cylindrical laser gyro using a cylindrical gyro main body.

(Prior Art) Various types of laser gyroscopes have been proposed based on the principle known as the Sannyac effect.

FIG. 5 is a plan view showing a conventional laser gyro employing a ring laser system.

The four gas tubes 11, 12, 13, and 14 are arranged on each side of a square with one side of 1 m.

A ring-shaped optical path is formed by plane mirrors 16 and 17, a curved mirror 18, and an output mirror 19.

20 is a coupling mirror, and 22 is a detector.

The laser gyro has a Sagnac interferometer configuration as shown in Figure 7, and the light emitted from the light source A is divided into clockwise and counterclockwise optical paths by C. When the laser gyro system rotates, the optical path difference is determined according to the angular velocity. Occurs between clockwise and counterclockwise rotations.

Due to the optical path difference, the interference fringes caused by the two light waves move, and the angular velocity can be detected.

FIG. 6 is a plan view showing another embodiment of a laser gyroscope using an optical fiber and a laser oscillator.
The optical fiber is wrapped around the drum multiple times to improve detection efficiency.

Since the detection sensitivity is improved by increasing the number of rotations of the optical path, the fiber coil has a structure in which the fiber is wound many times into a frame shape.

(Problems to be Solved by the Invention) All of the above-mentioned gyroscopes have large mass systems, and are unsuitable for motion control that requires nimble movements.

An object of the present invention is to provide a small laser gyroscope with a novel shape.

(Means for Solving the Problems) In order to achieve the above object, the cylindrical laser gyroscope according to the present invention has a laser beam incident and output surface on a part of the outer cylindrical surface, and another part of the outer cylindrical surface. a gyro body made of a transparent optical material whose inner surface serves as an optical reflection surface; a beam splitter disposed corresponding to the incident and exit surfaces; and the optical material of the gyro body via the beam splitter. an oscillator that projects a laser beam so that it is reflected and rotated clockwise and counterclockwise within the gyro body, and a laser beam that is emitted after being reflected and rotated clockwise within the gyro body and is reflected many times in each counterclockwise direction. It consists of a detector that detects the phase difference of the emitted laser beam.

(Example) Hereinafter, the present invention will be described in more detail with reference to the drawings and the like.

FIG. 1 is a perspective view showing an embodiment of a cylindrical laser gyro according to the present invention.

The gyro main body 1 is made of transparent quartz, and a reflective film 1a made of, for example, aluminum vapor deposition is provided on the outside of the outer periphery of the cylinder to efficiently reflect light.

The gyro body 1 also has a clockwise entrance surface (counterclockwise exit surface) 1b, a counterclockwise entrance surface (clockwise exit surface)
1c is provided.

A beam splitter 2 is placed at a position that equally divides the angle between each side of the gyro body, and a laser light source 3
The incident light from the gyro body 1 is made to enter the gyro main body 1. Light that enters the gyro main body 1 from the clockwise incidence surface (counterclockwise exit surface) 1b, is reflected many times, and is emitted from the counterclockwise incidence surface (clockwise exit surface) 1c is detected by the clockwise exit light detector 4. be done.

Similarly, the light that enters the gyro main body 1 from the counterclockwise entrance surface (clockwise exit surface) 1c, is reflected many times, and exits from the clockwise entrance surface (counterclockwise exit surface) 1b is detected as a counterclockwise exit light. detected by the device 5. The detection results are compared by a calculator 6, and the acceleration applied to the gyro can be output.

FIG. 2 is a schematic diagram showing an example of an optical path within the gyro body.

In Figure 2, the clockwise light is a → 2 (reflection) →
It emits along the path 1b→M ₃ →M ₄ ~M ₁₁ →1c.

The counterclockwise light follows the path a→2 (transmission)→M ₁₁ to M ₃ →1b and is emitted.

Assuming that the gyro body is placed in a stationary system, there should be no difference in optical path length between the clockwise and counterclockwise directions.

If the gyro main body 1 is placed in a rotating system around the center of a cylinder, an optical path difference will occur due to the aforementioned Sagnac effect.

Therefore, an optical path difference occurs in the laser beam, making it possible to detect the rotational angular velocity of the system.

FIG. 3 is a schematic diagram showing an example in which the angle of incidence can be varied depending on the position of the beam.

Change the incident angles α, γ, and the exit angles β, δ slightly in the tangential direction of the virtual circumference of the cylinder (this term is used because the incident part is not a cylindrical surface) at the entrance and exit points. Then, the number of reflections and rotations that maintain a certain relationship from entering the point of incidence until exiting from the point of injection are calculated.

An example of an optical path due to a difference in incidence angle is shown.

DEG: Angle between the normal to the virtual cylindrical surface and the incident ray at the point of incidence M: Number of rotations of light reflection on the cylindrical surface from the point of incidence until exit N: Total number of reflections + 2 DIS: When the radius is 1 Length (chord) between two points of reflection ADIS: Total distance between the incident point and the exit point when the radius is 1 DEG M N DIS
ADIS 45゜ 1 55 1.41
5.66 46゜ 11 46 1.39
62.52 47゜ 43 181 1.36
245.52 48゜ 6 31 1.34
40.15 Figure 4 schematically shows the optical path for an angle of incidence of 48°.

In a stationary system, for example, light incident at an angle of 43° (90°-47°) to the tangent to a disk with a radius of 100 mm will be incident 179 times (=N-
2) It is reflected, rotates 43 (=M), and returns to a range of 1/1000 of the radius, that is, a range of ±0.05 mm from the point of incidence.

In this case, the total travel distance of the light can be estimated to be 24,550 mm.

By appropriately selecting the incident angle conditions in this manner, it is possible to further increase the number of reflections, that is, the number of reflection rotations within the disk.

This means that high sensitivity can be achieved as a laser gyro.

Note that by entering the laser beam at a slight inclination to the plane perpendicular to the central axis of the cylinder,
The light is rotated and reflected in a spiral within the gyro body, so that the heights of the incident and exit positions of the light are different.

In this way, for example, as shown in FIG. 1, the heights of the optical axis of the laser and the optical axis of the detector can be shifted.

(Effects of the Invention) As described above in detail, the cylindrical laser gyroscope according to the present invention has a simple and stable optical system, and is small and lightweight while having high sensitivity like a fiber type.

Therefore, the cylindrical laser gyroscope according to the present invention can be used for displacement and attitude control of vehicles such as automobiles, robot arms, and the like.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of a cylindrical laser gyro according to the present invention. FIG. 2 is a plan view showing the optical path within the gyro body. FIG. 3 is a schematic diagram showing the relationship between the angle of incidence and the path. FIG. 4 is a schematic diagram of the light incidence and output angles. FIG. 5 is a schematic diagram of a ring laser gyroscope. FIG. 6 is a schematic diagram of an optical fiber gyroscope. FIG. 7 is a schematic diagram for explaining the principle of the Sagnac interferometer. 1... Gyro main body, 1a... Cylindrical reflecting surface of the gyroscope main body, M1 _to Mi... Reflection points on the cylindrical reflecting surface of the main body, 1b... Clockwise incidence surface (counterclockwise exit surface),
1c... Counterclockwise entrance surface (clockwise exit surface), 2...
Beam splitter, 3...Laser light source, 4...Clockwise emission light detector, 5...Counterclockwise emission light detector,
6...Arithmetic unit.

Claims (1)

[Scope of Claims] 1. A gyro main body made of a transparent solid optical material, in which a part of the cylindrical surface on the outer periphery is an incident and exit surface for laser light, and the inner surface of the other part of the cylindrical surface on the outer periphery is an optical reflection surface. , a beam splitter disposed corresponding to the incident and exit surfaces, and a laser beam reflected and rotated clockwise and counterclockwise into the optical material of the gyro body via the beam splitter. It is composed of an oscillator that emits light, and a detector that detects the phase difference between the laser light that is emitted after being reflected and rotated clockwise within the gyro body and the laser light that is emitted after being reflected many times in the counterclockwise direction. Cylindrical laser gyroscope.