JP6682730B2 - Optical scanning device - Google Patents

Description

  The present invention relates to an optical scanning device.

  An optical scanning device using a laser beam for performing three-dimensional distance measurement has been proposed in the past and, for example, configurations such as Patent Document 1 and Patent Document 2 are disclosed.

The optical scanning device disclosed in Patent Document 1 is provided with a flat reflecting mirror that rotates around both a horizontal rotation axis and a vertical rotation axis.
The flat reflecting mirror specularly reflects the light emitted from the light emitting element to the measurement space, and then specularly reflects the reflected light returning from the object in the measurement space and returning it to the light receiving element.
The flat reflector is supported by a mirror mount so as to rotate about a horizontal rotation axis. The mirror mount is provided with a rotation guide shaft that is inserted into a guide rail formed on the inner wall surface of the vertical moving body.
Further, the flat reflecting mirror is provided so as to rotate about a vertical rotation axis by a rotating member to which a rotational force of a motor (electric motor) is applied.
Therefore, due to the rotation of a single motor, the flat reflecting mirror swings around the horizontal axis of rotation and at the same time rotates around the vertical axis of rotation.

In addition, the optical scanning device disclosed in Patent Document 2 includes a mechanism that rotates a flat reflecting mirror about a vertical rotation axis and a horizontal rotation axis with a single motor. The rotational driving force of this motor is transmitted to a spur gear that rotates the gearbox, and the gearbox rotates about a vertical rotation axis.
A hollow worm gear that does not rotate is arranged at the center of the vertical rotation shaft.
The worm wheel that is screwed into the hollow worm gear is provided inside the gear box, and rotates by screwing into the worm gear as the gear box rotates.
A spur gear connected to the horizontal rotating shaft of the flat reflecting mirror is attached to the rotating shaft of the worm wheel. The flat reflector rotates around a horizontal axis of rotation that rotates vertically together with the gearbox.
That is, the rotation of the single motor causes the flat reflecting mirror to rotate about the horizontal rotation axis and the vertical rotation axis.

JP, 2010-527024, A Japanese Patent No. 5620603

In the optical scanning device of Patent Document 1 described above, as shown in FIG. 27 or 29, scanning lines are formed obliquely with respect to the target space, and a plurality of oblique scanning lines intersect to form a grid pattern. It is formed so as to draw the pattern of.
Also, in the optical scanning device of Patent Document 2, as in Patent Document 1, as shown in FIG. 5, scanning lines are formed obliquely with respect to the target space, and a plurality of oblique scanning lines intersect. It is formed to draw a spiral pattern.

Depending on the application, some optical scanning devices are equipped with a laser measurement unit that emits laser light toward the measurement target and receives the laser light reflected by the measurement target. The distance to the measurement target is calculated by measuring the round-trip time of light. At this time, the laser measurement unit requires a predetermined time (for example, 25 μsec) to measure the distance at one point, and during that time, the unique laser beam is emitted based on the distance measurement method.
Therefore, the scanning line as shown in Patent Document 1 or Patent Document 2 is a locus when laser light for distance measurement is tentatively continuously irradiated, and the point where distance measurement is performed on this locus is The existence of the distance does not mean that the distance measurement of each point can be performed with such a density, and in reality, there is a practically non-negligible interval between the measurement points.

In the above-described conventional optical scanning device, when increasing the density of the scanning lines with respect to the measurement target, both the rotation speed about the horizontal rotation axis of the plane reflecting mirror and the rotation speed about the vertical rotation axis It is possible by adjusting the rotation speed of.
However, depending on the rotation speed of both, the range where the scanning line does not exist becomes wide, and the density of the scanning line may decrease depending on the location.

  Therefore, the present invention has been made to solve the above problems, and an object thereof is to provide an optical scanning device capable of appropriately increasing the density of scanning lines by narrowing the range where scanning lines do not exist as much as possible. Especially.

According to the optical scanning device of the present invention, the optical scanning device can rotate about a vertical rotation axis having a vertical direction as an axis, and can rotate about a horizontal rotation axis having a horizontal direction as an axis, and can be parallel to the horizontal rotation axis. Is located at a position where the scanning light is incident on the reflecting surface along various directions, and the reflecting mirror irradiates the measuring object with the scanning light and receives the reflected light from the measuring object, and the reflecting mirror is rotated around the horizontal rotation axis. A first electric motor for rotating the reflecting mirror about a vertical rotation axis; and a control unit for controlling the number of rotations of the first electric motor and the second electric motor. In the case where the ratio RR1 of the number of revolutions of the second electric motor to the number of revolutions of the first electric motor is expressed as M / N by M and N which are both positive integers, N / M becomes an even number. So that the first electric motor and the second electric motor It is characterized by controlling the rotation number.
By adopting this configuration, it is possible to prevent the scanning lines from intersecting in an area where the elevation angle and depression angle in the horizontal direction are particularly small. Therefore, the range where the scanning lines do not exist can be made as narrow as possible and the overall resolution can be improved. .

  According to the optical scanning device of the present invention, the optical scanning device can rotate about a vertical rotation axis having a vertical direction as an axis, and can rotate about a horizontal rotation axis having a horizontal direction as an axis, and is parallel to the horizontal rotation axis. Is located at a position where the scanning light is incident on the reflecting surface along various directions, and the reflecting mirror irradiates the measuring object with the scanning light and receives the reflected light from the measuring object, and the reflecting mirror is rotated around the horizontal rotation axis. A first electric motor, a second electric motor that rotates a reflecting mirror about a vertical rotation axis, a control unit that controls the number of rotations of the first electric motor and the second electric motor, and the first electric motor A first encoder for measuring the number of revolutions of the first electric motor, wherein the control unit divides, multiplies or divides the encoder output signal of the first encoder for measuring the number of revolutions of the first electric motor. Or, for the rotation of the second electric motor without multiplication As dynamic pulse, or it is characterized in that input to the second electric motor as the speed control clock pulse.

  According to the optical scanning device of the present invention, the optical scanning device can rotate about a vertical rotation axis having a vertical direction as an axis, and can rotate about a horizontal rotation axis having a horizontal direction as an axis, and can be parallel to the horizontal rotation axis. Is located at a position where the scanning light is incident on the reflecting surface along various directions, and the reflecting mirror irradiates the measuring object with the scanning light and receives the reflected light from the measuring object, and the reflecting mirror is rotated around the horizontal rotation axis. A first electric motor, a second electric motor that rotates a reflecting mirror about a vertical rotation axis, a control unit that controls the rotational speeds of the first electric motor and the second electric motor, and the second electric motor. A second encoder that measures the number of revolutions of the second electric motor, wherein the control unit divides, multiplies, or divides the encoder output signal of the second encoder that measures the number of revolutions of the second electric motor. Or, for the rotation of the first electric motor without multiplication As dynamic pulse, or it is characterized in that input to the first motor as the speed control clock pulse.

  According to the present invention, it is possible to appropriately narrow the range where there are no scanning lines and appropriately increase the density of scanning lines.

It is a block diagram showing a schematic structure of an optical scanning device. FIG. 3 is a perspective view showing an external configuration of an optical scanning device. It is a side view which shows the external appearance structure of an optical scanning device. It is an image figure by the conformal cylindrical projection of the scanning line when the reciprocal of the rotation speed ratio is an even number. It is an image figure by the conformal cylindrical projection of the scanning line when the reciprocal of the rotation speed ratio is an odd number.

(overall structure)
FIG. 1 shows a block diagram of a schematic configuration of the optical scanning device of the present embodiment.
The optical scanning device 30 irradiates the measuring object around the optical scanning device 30 with the laser light, measures the distance to the measuring object by the reflected light reflected by the measuring object, and the irradiation direction information of the laser light at the measured distance. The coordinate value of the three-dimensional coordinate system is calculated by adding, and the calculation of the three-dimensional coordinate value is performed a plurality of times while changing the irradiation direction of the laser light with respect to the surrounding space, and a plurality of coordinate values (point group data ) Is acquired, and the shape of the surrounding space is measured by this point cloud data. Laser light is mainly used as the light.
The laser light that reaches the measurement target is defined as the forward light, and the laser light reflected by the measurement target and returned is defined as the return light.

The optical scanning device 30 includes a laser measuring unit 31. The laser measurement unit 31 has a laser light emitting device 51 and a laser light receiving device 52 inside, and the laser light emitted from the laser light emitting device 51 is applied to the measurement target as outward light, reflected by the measurement target, and returned. The laser light receiving device 52 receives the returned light.
The laser measurement unit 31 measures the time from the irradiation of the laser light to the measurement target until the laser light is reflected by the measurement target and returns, and the multiplication of this time by the light speed calculates the round trip distance to the measurement target. it can. Note that there is also a method of calculating the distance by utilizing the phase difference of the laser light without actually measuring the round trip time.

Laser light as outward light is emitted from the laser measurement unit 31 in the horizontal direction. The laser light emitted from the laser measurement unit 31 in the horizontal direction is applied to the reflecting mirror 34.
The reflecting mirror 34 is attached to the rotation shaft of the first electric motor 32, and is rotated about the horizontal rotation axis Y by the rotational driving of the first electric motor 32. The horizontal rotation axis Y of the reflecting mirror 34 is provided so as to pass through the center of the reflecting surface of the reflecting mirror 34.

  A first encoder 37 is provided between the reflecting mirror 34 and the first electric motor 32. The first encoder 37 detects the rotation speed and phase of the rotation of the reflecting mirror 34 about the horizontal rotation axis Y, and sends the detection result to the control unit 36 described later.

The reflecting mirror 34 employs a rod mirror having a reflecting surface formed by inclining the tip of a cylindrical rod at a predetermined angle other than the direction perpendicular or parallel to the axial direction of the rod. The rod mirror is a reflecting surface formed by cutting a tip of a rod made of glass or the like at a predetermined angle and depositing a reflecting film of metal or the like on the cut surface.
In this embodiment, the predetermined angle is set to 45 °, but the predetermined angle is not limited to 45 °.

The reflecting mirror 34, the first encoder 37, and the first electric motor 32 are provided on the base 40 shown in FIGS. 2 to 3, and the base 40 is centered on the vertical rotation axis Z by the second electric motor 48. Rotate.
A second encoder 38 is provided between the second electric motor 48 and the base 40. The second encoder 38 detects the rotation speed and phase of the rotation of the base 40 about the vertical rotation axis Z, and sends the detection result to the control unit 36 described later.
The mounting position of the second encoder 38 is the Z axis in FIG. 2, and the driving force is transmitted from the output shaft of the second electric motor 48 to the Z axis via the first gear 49 and the second gear 50. .

The control unit 36 controls the operation of the laser measurement unit 31 and also controls the rotating operation of the first electric motor 32 and the second electric motor 48.
In addition, the control unit 36 detects the distance to the measurement target measured by the laser measurement unit 31, the rotation speed and phase of the horizontal rotation axis Y detected by the first encoder 37, and the second encoder 38. The rotation speed and phase of the vertical rotation axis Z are sent to the data processing device 55.

The data processing device 55 calculates the three-dimensional coordinate data of the measurement target point based on the distance to the measurement target received from the control unit 36 and the number of rotations and the phase of the horizontal rotation axis Y and the vertical rotation axis Z. This set of three-dimensional coordinate data is point cloud data, which represents the shape of the measurement target in a discrete form.
The data processing device 55 may be an ordinary personal computer or the like, or may be a dedicated device for data processing. In the case of an ordinary personal computer, software for calculating the three-dimensional coordinate data of the measurement target is installed in this personal computer.

(Specific configuration)
2 to 3 show a specific structure of the optical scanning device. However, the data processing device is omitted in FIGS.
The laser measurement unit 31 and the first electric motor 32 are provided on the base 40.
The base 40 includes an upper horizontal surface portion 41 that extends horizontally and in which the laser measurement unit 31 and the first electric motor 32 are arranged, a vertical shaft portion 42 that extends downward from the center of the upper horizontal surface portion 41, and a vertical shaft. The lower horizontal surface portion 43 extends in the horizontal direction from the lower end portion of the portion 42.

  The base 40 is rotated about the vertical rotation axis Z by the rotational drive of the second electric motor 48. The vertical rotation axis Z is provided so as to pass through the center of the vertical shaft portion 42.

The second electric motor 48 is arranged on the lower horizontal surface portion 43 of the base 40. The rotation shaft of the second electric motor 48 is connected to the first gear 49 located below the lower horizontal surface portion 43. The first gear 49 meshes with a second gear 50 connected to the lower portion of the vertical shaft portion 42. The second gear 50 is attached to the vertical shaft portion 42 so that the center thereof coincides with the vertical rotation axis Z.
A pedestal 60 is provided below the second gear 50, and the lower surface of the pedestal 60 contacts the floor or the desk when the optical scanning device 30 is placed on the floor or the desk.
As the second electric motor 48 operates, the first gear 49 revolves around the second gear 50, and the entire base 40 rotates about the vertical rotation axis Z. The second encoder 38 is provided between the second gear 50 and the base 40.

The upper horizontal surface portion 41 is provided with a mounting portion 44 extending upward. The first electric motor 32 is attached to the inside of the attachment portion 44, and the reflecting mirror 34 is attached to the rotating shaft of the first electric motor 32.
The position of the reflecting mirror 34 is set so that the vertical rotation axis Z passes through the center of the reflecting surface of the reflecting mirror 34.

A control unit 36 is provided on the lower surface of the upper horizontal surface portion 41 on the side where the laser measurement unit 31 is arranged.
In addition, the electrical wiring that connects the first encoder 37, the second encoder 38, the first electric motor 32, the second electric motor 48, and the control unit 36 is wired through the inside of the base 40. There is.

The laser light emitted from the laser measuring unit 31 is directly incident on the reflecting mirror 34, and the return light reflected by the reflecting mirror 34 is directly incident on the laser measuring unit 31. A lens may be used for the purpose of efficiently condensing the incoming backward light on the light receiving sensor.
Further, both the laser measuring unit 31 and the reflecting mirror 34 are arranged on the upper surface of the upper horizontal surface portion 41, and rotate together with the base 40 about the vertical rotation axis Z.

(Control method)
Hereinafter, the rotation operation control of the reflecting mirror 34 executed by the control unit 36 will be described.
The reflecting mirror 34 rotates and revolves around two axes of a horizontal rotation axis Y and a vertical rotation axis Z.
The control unit 36 controls the first electric motor 32 to control the rotation speed of the horizontal rotation axis Y (hereinafter, also referred to as rotation speed), and simultaneously controls the second electric motor 48 to control the vertical rotation. The number of revolutions of the rotation axis Z (hereinafter sometimes referred to as the revolution number of revolutions) is controlled.

Regarding the rotation speed and the revolution speed, when the rotation speed is R1 and the revolution speed is R2, and the rotation ratio of the revolution speed R2 to the rotation speed R1 is RR1,
RR1 = R2 / R1.
Then, the control unit 36 sets the rotation speed R1 and the revolution speed R2 so that N / M becomes an even number when represented by 1 / RR1 = N / M, where M and N are positive integers.

FIG. 4 shows a state of the scanning line when N / M is an even number, which is represented by a conformal cylindrical projection method when it is assumed to be spherical around the reflecting mirror 34 with the reflecting mirror 34 as the center. . Since the spherical surface is spread in a plane, the area of high latitude (the zenith direction and the bottom direction when viewed from the reflecting mirror 34) has an area extending in the longitude direction.
That is, the scanning lines in FIG. 4 are concentrated at one point at the zenith and the bottom when considering the case of a spherical shape, and the scanning lines do not intersect with each other at the equator portion (the middle portion between the zenith portion and the bottom portion). It extends in a zigzag shape in the vertical direction.

On the other hand, in FIG. 5, the scanning lines in the case where N / M is an odd number are represented by a conformal cylindrical projection method in a case in which the reflecting mirror 34 is assumed to be spherical around the reflecting mirror 34 as a center. Indicates.
In FIG. 5, the number of rotations of the first electric motor 32 is increased as compared with FIG. 4, so that the number of scanning lines is increased. However, the scanning lines intersect at the equator (the middle between the zenith and the bottom). As a result, even though the number of scanning lines is increased with respect to the condition of FIG. 4, in FIG. 5, the density of scanning lines near the equator is rather lowered.

  In FIG. 5, since the scanning lines intersect near the equator, the scanning line density near the equator is small. On the other hand, there is no significant difference in that the scanning lines are concentrated in the zenith and the bottom even if N / M is even or odd.

  Thus, by setting N / M to an even number, it is possible to appropriately increase the density of scanning lines.

(Specific control method 1)
Next, a specific control method for controlling the rotation speeds of the first electric motor 32 and the second electric motor 48 of the control unit 36 will be described.
First, the control unit 36 divides the encoder output signal of the first encoder 37, which measures the rotation speed of the first electric motor 32, into 1 / n1 times or multiplies by n2 times. Note that n1 and n2 are positive integers. However, in some cases, it is not necessary to divide or multiply the encoder output signal.

  When the second electric motor 48 is a stepping motor, a servo motor or a DC brushless motor, the control unit 36 divides the frequency by 1 / n1 times or multiplies by n2 times the encoder of the first electric motor 32. The output signal is input to the second electric motor 48 as a drive pulse for rotation of the second electric motor 48 or as a speed control clock pulse.

The number of pulses output per rotation of the first encoder 37 of the first electric motor 32 is MEP. Depending on the handling of the encoder signal, the MEP assumes the number of pulses actually used in the system among the number of A-phase pulses, the number of AB-phase pulses, and the number of pulses multiplied by a multiplier circuit.
As described above, the rotation ratio of the revolution speed R2 to the rotation speed R1 is RR1.
The reduction ratio when the rotation of the revolution shaft is driven from the second electric motor 48 via the speed change mechanism (the first gear 49 and the second gear 50 in this embodiment) is RR2. In the present embodiment, RR2 = Z1 / (Z1 + Z2), where Z1 is the number of gears of the first gear 49 and Z2 is the number of gears of the second gear 50.
In addition, the number of drive pulses or the number of speed control clock pulses required for the second electric motor 48 to make one rotation is LS.
The number of times the distance is measured by the first electric motor 32 while the reflecting mirror 34 rotates once is MN.

When dividing the encoder output signal into 1 / n1,
It is necessary that RR1 satisfies the above-mentioned conditions. Further, it is preferable that either MN = MEP or MN and MEP is a divisor of the other, but this may not be satisfied.
Then, MEP and the positive integer n1 are set as the number of pulses output per rotation of the RR1, RR2, and the first encoder 37 so that MEP = n1 × LS × (RR1 / RR2).

(Example of control method 1)
An example of the above-mentioned control method 1 will be described.
The measurement frequency F1 of the laser measurement unit 31 is 48000 Hz. This is set in advance in the laser unit 31.
For the time being, the rotation speed R1 of the reflecting mirror 34 is set to 2000 rpm and the revolution speed R2 is set to 10 rpm, and it is verified whether the objects of the present application can be achieved by these R1 and R2.

The number of measurements MN when the reflecting mirror 34 rotates once is
MN = F1 / (R1 / 60) = 48000 / (2000/60) = 1440
The number of drive pulses required for one rotation of the second electric motor 48 or the number of speed control clock pulses LS is 800. This is a constant determined by the structure of the electric motor and the control method.
Further, the gear ratio at the time of revolving the rotational drive of the second electric motor 48 is set to 1/30.

If the number is set as above,
Since 1 / RR1 = R1 / R2 = 2000/10 = 200, which is an even number, the condition is satisfied.
Then, MN = MEP or one of MN and MEP satisfies the divisor of the other, and MEP and a positive integer n1 such that MEP = n1 × 800 × (200 / (1/30)). To set.
When MN = MEP = 1440,
MEP = n1 × LS × (RR1 / RR2)
1440 = n1 × 800 × ((1/200) / (1/30))
n1 = 12
And satisfy the condition. That is, it is understood that the encoder output signal may be set to be divided into 1/12.

  Therefore, by setting the rotation speed R1 to 2000 rpm, the revolution speed R2 to 10 rpm, and setting other necessary parameters, the pulse signal from the first electric motor 32 is divided to the second electric motor 48. If input, the scanning line density of the required portion can be increased, and the resolution can be increased as a whole.

  In the above embodiment, the case where the encoder output signal is divided into 1 / n1 has been described, but a specific numerical value can be similarly set in the case of multiplying by n2.

It is also possible to input the encoder output signal to the second electric motor 48 as a drive pulse for rotation of the second electric motor 48 or as a clock pulse for speed control without dividing or multiplying the encoder output signal. , RR1 needs to satisfy the above-mentioned condition, and it is preferable that either MN = MEP or one of MN and MEP is a divisor of the other, but this may not be satisfied.
Then, the number of pulses MEP to be output per rotation of the RR1, RR2, and the first encoder 37 may be set so that n2 × MEP = LS × (RR1 / RR2).

(Specific control method 2)
The control method 2 described below is different from the above-described control method 1 in that it is input to the first electric motor 32 by using the encoder output signal of the second encoder 38 of the second electric motor 48.
First, the control unit 36 divides the encoder output signal of the second encoder 38, which measures the rotation speed of the second electric motor 48, into 1 / n1 times or multiplies it by n2 times. Note that n1 and n2 are positive integers. However, in some cases, it is not necessary to divide or multiply the encoder output signal.

  When the first electric motor 32 is a stepping motor, a servo motor, or a DC brushless motor, the control unit 36 divides the frequency by 1 / n1 times or multiplies the second electric motor 48 by n2 times. The encoder output signal of is input to the first electric motor 32 as a drive pulse for rotation of the first electric motor 32 or as a clock pulse for speed control.

The number of pulses output per rotation of the second encoder 38 of the second electric motor 48 is SEP. The SEP assumes the number of pulses actually used in the system among the number of A-phase pulses, the number of AB-phase pulses, and the number of pulses multiplied by a multiplier circuit, depending on the handling of encoder signals.
As described above, the rotation ratio of the revolution speed R2 to the rotation speed R1 is RR1.
The number of drive pulses or the number of speed control clock pulses required for the first electric motor 32 to make one rotation is LM.
The number of times the distance is measured by the first electric motor 32 while the reflecting mirror 34 rotates once is MN.

When dividing the encoder output signal into 1 / n1,
It is necessary that RR1 satisfies the above-mentioned conditions. It is preferable that one of MN = SEP × RR1 or MN and SEP × RR1 is a divisor of the other, but this may not be satisfied.
Then, RR1, the number of pulses SEP output per one rotation of the second encoder 38, and a positive integer n1 are set so that n1 × LM × SEP = RR1.

When multiplying the encoder output signal by n2 times,
It is necessary that RR1 satisfies the above-mentioned conditions. It is preferable that one of MN = SEP × RR1 or MN and SEP × RR1 is a divisor of the other, but this may not be satisfied.
Then, RR1, the number of pulses SEP output per rotation of the second encoder 38, and a positive integer n2 are set so that LM × SEP = n2 × RR1.

It should be noted that the encoder output signal may be input to the first electric motor 32 as a drive pulse for rotation of the first electric motor 32 or as a speed control clock pulse without being divided or multiplied. Also, it is necessary that RR1 satisfies the above-mentioned condition. It is preferable that one of MN = SEP × RR1 or MN and SEP × RR1 is a divisor of the other, but this may not be satisfied.
Then, RR1 and the number of pulses SEP output per rotation of the second encoder 38 are set so that LM × SEP = RR1.

(Other conditions)
In addition to the above condition that N / M is an even number,
When the rotation ratio of the revolution speed R2 to the rotation speed R1 is RR1 and RR1 = R2 / R1 = M / N (M and N are positive integers),
There may be a condition that the positive integers M and N do not have a common divisor other than 1 (hereinafter, this condition is referred to as condition 2).

For example, when the numerical values selected by the control unit 36 are M = 17 and N = 20, the condition 2 is satisfied because the common divisor is only 1.
However, when the numerical values selected by the control unit 36 are M = 15 and N = 20, the common divisor is 5, which is a numerical value other than 1. When considering RR1 = M / N, this is RR1 = 15/20 = 3/4, which is substantially the same as M = 3 and N = 4.

When one cycle of scanning of the reflecting mirror 34 is considered based on the rotation speed of rotation, when the numerical values satisfying the condition 2 are M = 17 and N = 20, the rotation of the rotation of the reflection mirror 34 revolves 17 times while rotating 20 times.
However, when the numerical values M = 15 and N = 20 that do not satisfy the condition 2, since they are substantially the same as M = 3 and N = 4, three revolutions are performed during four rotations, and one cycle of scanning is completed. For this reason, if the condition 2 is not satisfied, the density of scanning lines per one cycle will decrease.
Satisfying the condition 2 means that the common divisor is an integer ratio other than 1, so that one scanning cycle becomes long, and when the scanning cycle may be lengthened, the density of scanning lines is increased by this method. be able to.

In addition to condition 2 above,
As condition 3, M and N may satisfy the following two expressions.
M and N are positive integers I and J,
N = I × J ± 1, M = I (1) is satisfied, or
N = I × J, M = I ± 1 (2) are satisfied.

  The above two expressions (1) and (2) of the condition 3 are intended to set the value of M to a value obtained by shifting 1 from a multiple of N. As a result, it is possible to surely realize that there is no common divisor other than condition 1 and to make the rotation ratio RR1 close to an integral multiple.

For example, when M = 19 and N = 20,
If I = 20 and J = 1, then N = I × 1 = 20 and M = 20 ± 1 = 19, which satisfies the equation (2).

  It should be noted that the conditions 2 and 3 and the condition that N / M in the present invention is set to an even number may not be satisfied at the same time, so condition 2 or condition 3 is a condition that N / M in the present invention is set to an even number. Is effective when cannot be adopted.

  The shape of the base 40, the arrangement position of the laser measurement unit 31, the arrangement position of the control unit 36, etc. are not limited to the above-described embodiment.

30 Optical Scanning Device 31 Laser Measuring Unit 32 First Motor 34 Reflector 36 Control Unit 37 First Encoder 38 Second Encoder 40 Base 41 Upper Horizontal Plane Section 42 Vertical Axis Section 43 Lower Horizontal Plane Section 44 Mounting Section 48 Second Electric motor 49 First gear 50 Second gear 51 Laser emitting device 52 Laser receiving device 55 Data processing device 60 Pedestal

Claims (3)

It is possible to rotate about a vertical axis of rotation that has the vertical axis as the axis and that can rotate about a horizontal axis of rotation that has the horizontal direction as the axis, and the scanning light is reflected on the reflecting surface along a direction parallel to the horizontal axis of rotation. A reflecting mirror that is arranged at an incident position, irradiates the measurement target with scanning light, and receives reflected light from the measurement target,
A first electric motor for rotating the reflecting mirror about a horizontal axis of rotation;
A second electric motor for rotating the reflecting mirror about the vertical rotation axis,
A control unit for controlling the number of revolutions of the first electric motor and the second electric motor,
The control unit is
When the rotation speed ratio RR1 of the second electric motor to the rotation speed of the first electric motor is expressed as M / N by M and N which are both positive integers,
An optical scanning device, characterized in that the rotational speeds of the first electric motor and the second electric motor are controlled so that N / M is even. It is possible to rotate about a vertical axis of rotation that has the vertical axis as the axis and that can rotate about a horizontal axis of rotation that has the horizontal direction as the axis, and the scanning light is reflected on the reflecting surface along a direction parallel to the horizontal axis of rotation. A reflecting mirror that is arranged at an incident position, irradiates the measurement target with scanning light, and receives reflected light from the measurement target,
A first electric motor for rotating the reflecting mirror about a horizontal axis of rotation;
A second electric motor for rotating the reflecting mirror about the vertical rotation axis,
A control unit that controls the rotation speeds of the first electric motor and the second electric motor;
A first encoder for measuring the number of revolutions of the first electric motor,
The control unit is
The encoder output signal of the first encoder for measuring the rotation speed of the first electric motor is divided, multiplied, or as a drive pulse for rotation of the second electric motor without being divided or multiplied, or a speed. An optical scanning device characterized in that it is inputted to the second electric motor as a control clock pulse. It is possible to rotate about a vertical axis of rotation that has the vertical axis as the axis and that can rotate about a horizontal axis of rotation that has the horizontal direction as the axis, and the scanning light is reflected on the reflecting surface along a direction parallel to the horizontal axis of rotation. A reflecting mirror that is arranged at an incident position, irradiates the measurement target with scanning light, and receives reflected light from the measurement target,
A first electric motor for rotating the reflecting mirror about a horizontal axis of rotation;
A second electric motor for rotating the reflecting mirror about the vertical rotation axis,
A control unit that controls the rotation speeds of the first electric motor and the second electric motor;
A second encoder for measuring the number of revolutions of the second electric motor,
The control unit is
The encoder output signal of the second encoder for measuring the number of revolutions of the second electric motor is divided, multiplied, or as a driving pulse for rotation of the first electric motor without being divided or multiplied, or a speed. An optical scanning device, wherein a clock pulse for control is input to the first electric motor.