JP2017156142A - Optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanner which can increase the entire resolution by reducing the area with no scanning lines as much as possible.SOLUTION: A controller 36 controls the number of rotations of a first electric motor 32 and of a second electric motor 48 so that N/M becomes even when the ratio RR1 of the number of rotations of the second electric motor 48 to the number of rotations of the first electric motor 32 is denoted by M/N (N and M are positive integers).SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical scanning device.

  Conventionally, an optical scanning device using a laser beam to perform three-dimensional distance measurement has been proposed. For example, configurations such as Patent Document 1 and Patent Document 2 are disclosed.

The optical scanning device disclosed in Patent Document 1 includes a flat plate reflecting mirror that rotates around both a horizontal rotation axis and a vertical rotation axis.
This flat reflector reflects the light emitted from the light emitting element into the measurement space and then reflects the reflected light reflected by the object in the measurement space again to send 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 rotating guide shaft that is inserted into a guide rail formed on the inner wall surface of the vertical moving body.
The flat reflector is provided so as to rotate about the vertical rotation axis by a rotating member to which a rotational force of a motor (electric motor) is applied.
For this reason, the flat mirror is rotated about the horizontal rotation axis and simultaneously rotated about the vertical rotation axis by the rotational drive of a single motor.

In addition, the optical scanning device disclosed in Patent Document 2 includes a mechanism that rotates a flat reflector around 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 gear box, and the gear box rotates about the 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 in the gear box, and is rotated by screwing with the worm gear as the gear box rotates.
A spur gear connected to the horizontal rotating shaft of the flat reflector is attached to the rotating shaft of the worm wheel. The flat plate mirror rotates about a horizontal rotation axis that rotates vertically integrally with the gear box.
That is, the flat mirror is rotated about the horizontal rotation axis and the vertical rotation axis by the rotational drive of a single motor.

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 FIG. 29, scanning lines are formed obliquely with respect to the target space, and a plurality of oblique scanning lines intersect to form a lattice pattern. It is formed so as to draw a pattern.
Further, in the optical scanning device of Patent Document 2, similarly to 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 include a laser measurement unit. The laser measurement unit emits laser light toward the measurement target, and receives the laser light reflected from the measurement target. The distance to the measurement object 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 of one point, and during this time, irradiation with a specific laser beam based on the distance measurement method is performed.
Therefore, a scanning line as shown in Patent Document 1 or Patent Document 2 is a trajectory when laser light for distance measurement is continuously irradiated, and the point at which distance measurement is performed on this trajectory is Just because it exists, it does not mean that the distance measurement of each point can be performed at such a density, but in reality, there is a practically non-negligible interval between the measurement points.

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

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide an optical scanning device capable of appropriately increasing the density of scanning lines by narrowing a range in which scanning lines do not exist as much as possible. There is.

According to the optical scanning device of the present invention, the optical scanning device can be rotated about a vertical rotation axis having the vertical direction as an axis, and can be rotated about a horizontal rotation axis having the horizontal direction as an axis, and parallel to the horizontal rotation axis. Is placed at a position where the scanning light is incident on the reflecting surface along a specific direction, irradiates the measuring object with the scanning light, receives the reflected light from the measuring object, and rotates the reflecting mirror around the horizontal rotation axis A first electric motor to be driven; a second electric motor that rotates a reflecting mirror around a vertical rotation axis; and a control unit that controls the number of rotations of the first electric motor and the second electric motor. When the ratio RR1 of the second electric motor to the rotation speed of the first electric motor is expressed as M / N by both positive integers M and N, N / M is an even number. Of the first electric motor and the second electric motor so as to satisfy It is characterized by controlling the rotation number.
By adopting this configuration, it is possible to prevent the scanning lines from intersecting particularly in a region where the elevation angle depression angle in the horizontal direction is small, so that the range where the scanning lines do not exist can be made as narrow as possible and the overall resolution can be increased. .

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

  According to the present invention, it is possible to narrow the range in which the scanning lines do not exist as much as possible and appropriately increase the density of the scanning lines.

It is a block diagram which shows schematic structure of an optical scanning device. It is a perspective view which shows the external appearance structure 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 regular-angle cylindrical projection of a scanning line when the reciprocal number of a rotation speed ratio is an even number. It is an image figure by the regular-angle cylindrical projection of a scanning line when the reciprocal number of a 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 measurement target around the optical scanning device 30 with laser light, measures the distance to the measurement target with the reflected light reflected by the measurement target, and applies the laser beam irradiation direction information to the measured distance. Is used to calculate the coordinate value of the three-dimensional coordinate system, 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 the shape of the surrounding space is measured by this point cloud data. As light, laser light is mainly used.
The laser light until reaching the measurement target is defined as forward light, and the laser light reflected and returned from the measurement target is defined as return light.

The optical scanning device 30 includes a laser measurement 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 irradiated to the measurement object as forward light, reflected by the measurement object and returned. The laser light receiving device 52 receives the returning light.
The laser measurement unit 31 measures the time from irradiation of the laser beam to the measurement object to reflection and return from the measurement object, and calculates the round-trip distance to the measurement object by multiplying this time by the speed of light. it can. In addition, there is also a method of calculating the distance using the phase difference of the laser beam without actually measuring the round trip time.

Laser light as forward light is emitted from the laser measurement unit 31 in the horizontal direction. The laser beam irradiated in the horizontal direction from the laser measurement unit 31 is applied to the reflecting mirror 34.
The reflecting mirror 34 is attached to the rotation shaft of the first electric motor 32, and rotates about the horizontal rotation axis Y by the rotational drive of the first electric motor 32. Further, 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 rotation of the reflecting mirror 34 around 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 in which the tip of a cylindrical rod is inclined at a predetermined angle that is an angle other than perpendicular or parallel to the axial direction of the rod. The rod mirror is a reflecting surface formed by cutting the tip of a rod formed of glass or the like at a predetermined angle and depositing a reflecting film such as metal on the cutting surface.
In the present embodiment, the predetermined angle is 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 rotation about the vertical rotation axis Z of the base 40 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 rotation operations of the first electric motor 32 and the second electric motor 48.
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 rotation speed and phase of the horizontal rotation axis Y and the vertical rotation axis Z. A set of the three-dimensional coordinate data is point cloud data, and the shape to be measured is discretized and expressed.
The data processing device 55 may be an ordinary personal computer or the like, or may be a dedicated machine for data processing. In the case of an ordinary personal computer, software for calculating three-dimensional coordinate data to be measured is installed in the personal computer.

(Specific configuration)
2 to 3 show a specific structure of the optical scanning device. However, the data processing apparatus 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 in the horizontal direction and on which the laser measurement unit 31 and the first electric motor 32 are disposed, a vertical shaft portion 42 that extends downward from the center of the upper horizontal surface portion 41, and a vertical shaft A lower horizontal surface portion 43 extending in the horizontal direction from the lower end of the portion 42.

  The base 40 rotates 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 disposed on the lower horizontal surface portion 43 of the base 40. A rotation shaft of the second electric motor 48 is connected to a first gear 49 located below the lower horizontal plane portion 43. The first gear 49 meshes with the 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 desk when the optical scanning device 30 is placed on the floor or desk.
As the second electric motor 48 operates, the first gear 49 revolves around the second gear 50, and the entire base 40 rotates around 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 rotation 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 disposed.
In addition, the electrical wiring connecting 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. Yes.

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. In addition, a lens may be used for the purpose of efficiently condensing incident return light to the light receiving sensor.
The laser measurement unit 31 and the reflecting mirror 34 are both disposed 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, a horizontal rotation axis Y and a vertical rotation axis Z.
The control unit 36 controls the first motor 32 to control the rotation speed of the horizontal rotation shaft Y (hereinafter sometimes referred to as the rotation speed), and simultaneously controls the second motor 48 to control the vertical rotation. The number of rotations of the rotation axis Z (hereinafter sometimes referred to as revolution number of rotations) is controlled.

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

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

On the other hand, FIG. 5 shows the state of the scanning line when N / M is an odd number in a case where it is assumed to be a sphere around the reflecting mirror 34 around the reflecting mirror 34 and expressed in a regular cylindrical projection. Indicates.
In FIG. 5, the number of scanning lines is increased because the number of rotations of the first electric motor 32 is increased as compared with FIG. 4. However, the scanning lines intersect at the equator part (intermediate part between the zenith part and the bottom part). This results in a decrease in the density of the scanning lines near the equator in FIG. 5 despite increasing the number of scanning lines with respect to the conditions of FIG.

  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 between the zenith and the bottom in that the scanning lines are concentrated regardless of whether N / M is even or odd.

  Thus, by setting N / M to an even number, the density of the scanning line can be appropriately increased.

(Specific control method 1)
Next, a specific control method for controlling the rotation speeds of the first motor 32 and the second 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 that measures the rotation speed of the first electric motor 32 into 1 / n1 times or multiplies it by n2. N1 and n2 are positive integers. However, the encoder output signal may not be divided or multiplied.

  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 the first electric motor 32 by n2 times. The output signal is input to the second electric motor 48 as a driving pulse for rotation of the second electric motor 48 or as a clock pulse for speed control.

The number of pulses output per rotation of the first encoder 37 of the first electric motor 32 is defined as MEP. MEP assumes the number of pulses actually used in the system among the number of pulses of the A phase, the number of pulses obtained by multiplying the AB phase, and the number of pulses multiplied using the multiplication circuit by handling the encoder signal.
As described above, the rotation ratio of the revolution speed R2 to the rotation speed R1 is RR1.
RR2 is a 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). In the present embodiment, when the number of gears of the first gear 49 is Z1, and the number of gears of the second gear 50 is Z2, RR2 = Z1 / (Z1 + Z2).
Further, the number of driving pulses or the number of clock pulses for speed control necessary for the second electric motor 48 to make one rotation is LS.
The number of times the distance measurement is performed while the reflecting mirror 34 rotates once by the first electric motor 32 is MN.

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

(Example of control method 1)
An embodiment of the control method 1 described above 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 object of the present application can be achieved with 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 or the number of speed control clock pulses LS necessary for one rotation of the second motor 48 is 800. This is a constant determined by the structure of the motor and the control method.
Further, the gear ratio when the rotational drive of the second electric motor 48 is revolved is set to 1/30.

For numbers set as above,
Since 1 / RR1 = R1 / R2 = 2000/10 = 200, which is an even number, the condition is satisfied.
Then, MN = MEP or MN and MEP satisfy that either one is a divisor of the other, and MEP and positive integer n1 such that MEP = n1 × 800 × (200 / (1/30)) 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 can be understood that the encoder output signal may be set to be divided by 1/12.

  Therefore, the rotation speed R1 is set to 2000 rpm, the revolution speed R2 is set to 10 rpm, and other necessary parameters are set, so that the pulse signal from the first motor 32 is divided to the second motor 48. If it is input, the scanning line density at a necessary location can be increased, and the overall resolution can be increased.

  In the above embodiment, the case where the encoder output signal is divided by 1 / n1 has been described. However, even when the encoder output signal is multiplied by n2, specific numerical values can be similarly set.

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

(Specific control method 2)
Unlike the control method 1 described above, the control method 2 described below is a case where the first motor 32 is input using the encoder output signal of the second encoder 38 of the second motor 48.
First, the control unit 36 divides the encoder output signal of the second encoder 38 that measures the rotation speed of the second electric motor 48 into 1 / n1 times or multiplies it by n2. N1 and n2 are positive integers. However, the encoder output signal may not be divided or multiplied.

  When the first 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 the second motor 48 multiplied by n2 times. The encoder output signal 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. SEP assumes the number of pulses actually used in the system among the number of pulses of the A phase, the number of pulses obtained by multiplying the AB phase, and the number of pulses multiplied using the multiplication circuit by handling the encoder signal.
As described above, the rotation ratio of the revolution speed R2 to the rotation speed R1 is RR1.
The number of driving pulses or the number of clock pulses for speed control necessary for the first motor 32 to make one rotation is LM.
The number of times the distance measurement is performed while the reflecting mirror 34 rotates once by the first electric motor 32 is MN.

When dividing the encoder output signal to 1 / n1,
It is necessary for RR1 to satisfy the conditions described above. 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 n1 are set so that n1 × LM × SEP = RR1.

When multiplying the encoder output signal by n2 times,
It is necessary for RR1 to satisfy the conditions described above. 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.

Note 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 clock pulse for speed control without being divided or multiplied. In addition, it is necessary that RR1 satisfies the above-described 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 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-mentioned 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),
The condition that the positive integers M and N have no common divisor other than 1 (hereinafter, this condition is referred to as condition 2) may be used.

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

Assuming that one period of scanning of the reflecting mirror 34 is based on the rotation speed, when the numerical values satisfying the condition 2 are M = 17 and N = 20, the rotation is revolved 17 times during 20 rotations.
However, in the case of numerical values M = 15 and N = 20 that do not satisfy the condition 2, since M = 3 and N = 4 are substantially the same, three revolutions are performed during four rotations, and one cycle of scanning is completed. For this reason, when the condition 2 is not satisfied, the density of the scanning lines per cycle is lowered.
In addition, satisfying Condition 2 is an integer ratio in which the common divisor is not other than 1. Therefore, when one scanning period is long and the scanning period may be long, the density of scanning lines is increased by this method. be able to.

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

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

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

  Note that conditions 2 and 3 and the condition that N / M in the present invention is 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 an even number. This 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, and the like are not limited to the above-described embodiments.

30 optical scanning device 31 laser measurement unit 32 first electric motor 34 reflecting mirror 36 control unit 37 first encoder 38 second encoder 40 base 41 upper horizontal plane portion 42 upper shaft portion 43 lower horizontal plane portion 44 attachment portion 48 second Motor 49 first gear 50 second gear 51 laser light emitting device 52 laser light receiving device 55 data processing device 60 pedestal

Claims (3)

It can rotate around a vertical rotation axis with the vertical direction as the axis, and can rotate around a horizontal rotation axis with the horizontal direction as the axis, and the scanning light is reflected on the reflecting surface along the direction parallel to the horizontal rotation axis. A reflecting mirror that is arranged at an incident position, irradiates the measuring object with scanning light, and receives reflected light from the measuring object;
A first electric motor that rotates a reflecting mirror around a horizontal rotation axis;
A second electric motor that rotates the reflecting mirror about the vertical rotation axis;
A controller that controls the number of revolutions of the first electric motor and the second electric motor,
The controller is
In the case where the rotation speed ratio RR1 of the second motor to the rotation speed of the first motor is expressed as M / N by both M and N being 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 as to satisfy that N / M is an even number. It can rotate around a vertical rotation axis with the vertical direction as the axis, and can rotate around a horizontal rotation axis with the horizontal direction as the axis, and the scanning light is reflected on the reflecting surface along the direction parallel to the horizontal rotation axis. A reflecting mirror that is arranged at an incident position, irradiates the measuring object with scanning light, and receives reflected light from the measuring object;
A first electric motor that rotates a reflecting mirror around a horizontal rotation axis;
A second electric motor that rotates the reflecting mirror about the vertical rotation axis;
A control unit for controlling the rotational speeds of the first electric motor and the second electric motor;
A first encoder for measuring the number of rotations of the first electric motor,
The controller is
Without dividing, multiplying, or dividing or multiplying the encoder output signal of the first encoder that measures the rotation speed of the first motor as a drive pulse for rotating the second motor, or speed An optical scanning device, wherein a control clock pulse is input to the second electric motor. It can rotate around a vertical rotation axis with the vertical direction as the axis, and can rotate around a horizontal rotation axis with the horizontal direction as the axis, and the scanning light is reflected on the reflecting surface along the direction parallel to the horizontal rotation axis. A reflecting mirror that is arranged at an incident position, irradiates the measuring object with scanning light, and receives reflected light from the measuring object;
A first electric motor that rotates a reflecting mirror around a horizontal rotation axis;
A second electric motor that rotates the reflecting mirror about the vertical rotation axis;
A control unit for controlling the rotational speeds of the first electric motor and the second electric motor;
A second encoder for measuring the rotation speed of the second electric motor,
The controller is
Without dividing, multiplying, or dividing or multiplying the encoder output signal of the second encoder that measures the rotation speed of the second motor as a drive pulse for rotating the first motor, or speed An optical scanning device, wherein a control clock pulse is input to the first electric motor.