JPWO2011155002A1 - Ranging device and traveling vehicle - Google Patents

Abstract

Reduce false detection of ranging device. The light projecting means (101) for projecting the laser light (L) and the laser light (L) projected from the light projecting means (101) are swept so that the optical axis rotates at an angle a with respect to the rotation axis C. A first sweeping means (102), and a light receiving means (103) for transmitting a signal when the reflected light (R) reflected by the laser light (L) projected from the light projecting means (101) hits the object is received. The angle a is 80 degrees ≦ a <90 degrees.

Description

  The present invention relates to a distance measuring device that projects laser light and obtains information related to a distance to an object based on reflected light from the object, and a traveling vehicle including the distance measuring device.

  A traveling vehicle such as an automatic guided vehicle is equipped with a distance measuring device using a laser beam in order to avoid collision with an obstacle and to avoid contact with an operator.

  This distance measuring device projects while rotating laser light, and receives reflected light reflected by objects such as traveling vehicles, obstacles, workers, etc., to determine whether the object is present in the danger area. Or detecting the distance to the object. The traveling vehicle is controlled on the basis of information obtained from the distance measuring device to avoid collision and contact.

  For example, in Patent Document 1, by irradiating a laser beam at a predetermined angle to a point that intersects with the rotation axis of the rotating mirror, the laser beam is rotated about the rotation axis of the mirror and the direction along the rotation axis A distance measuring device is disclosed that detects not only the distance of the object but also the angle of the object with respect to the distance measuring apparatus by meandering the laser beam.

  When the conventional distance measuring device is attached to each of a plurality of traveling vehicles and operated in one factory, the light projected from the distance measuring device attached to the one traveling vehicle becomes an unexpected object. The light may be reflected and received by a distance measuring device attached to another traveling vehicle. In this case, since the distance measuring device of other traveling vehicles will generate a false detection of detecting an unnecessary object, a malfunction occurs in the operation of the traveling vehicle as a whole factory, for example, the traveling vehicle stops. Sometimes.

  Therefore, conventionally, as shown in FIG. 5A, the distance measuring device 100 is attached to the traveling direction of the traveling vehicle 200 while being inclined by several degrees, so that the rotation axis C of the laser beam L to be projected is tilted. A method for avoiding erroneous detection between the cars 200 is employed.

JP 2009-236774 A

  However, when the distance measuring device 100 is simply tilted with respect to the traveling direction of the traveling vehicle, when the laser light L is projected perpendicular to the traveling direction of the traveling vehicle 200 as shown in FIG. It is projected in parallel with the floor surface F. In this case, erroneous detection between the traveling vehicles 200 may occur, which is a problem.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and aims to provide a distance measuring device capable of suppressing the occurrence of erroneous detection between traveling vehicles as much as possible, and a traveling vehicle including the distance measuring device. Yes.

  In order to achieve the above object, a distance measuring device according to the present invention is projected from the light projecting means for projecting laser light and the light projecting means so that the optical axis rotates at an angle a with respect to the rotation axis. A first sweeping means for sweeping the laser light; and a light receiving means for transmitting a signal when the laser light projected from the light projecting means hits an object and reflects the light, and the angle a is 80 Degrees ≦ a <90 degrees.

  The first sweeping unit includes a reflection unit that intersects the rotation axis and has a reflection surface that reflects the laser light projected from the light projecting unit, and a rotation unit that rotates the reflection unit around the rotation axis. The light projecting unit may irradiate a laser beam onto the reflection surface of the reflection unit along the rotation axis.

  According to this, since the angle at which the laser beam is projected does not change depending on the rotation angle, and the laser beam rotates while maintaining a constant angle with respect to the rotation axis, a plurality of the same kind of distance measuring devices are arranged. Even in this case, erroneous detection of receiving light projected from another distance measuring device can be suppressed as much as possible.

  In addition, since the projection angle of the laser beam is constant, when either one of the distance and the size (height) of the object is known, the other information is acquired depending on whether or not the reflected light is received. can do. For example, when the size of the object is known, it is possible to detect that the distance between the distance measuring device and the object is within a predetermined range by receiving the reflected light.

  The first sweeping unit may further include an angle changing unit that changes an angle of the reflecting surface with respect to the rotation axis.

  According to this, it becomes possible to change the threshold value for detecting the other from either one of the distance and the size (height) of the object, and the versatility of the distance measuring device can be improved. It becomes.

  And a second sweeping means for sweeping the light receiving direction so that the light receiving direction rotates at the angle a with respect to the rotation axis when the light receiving direction is the most sensitive direction in the visual field of the light receiving means. It may be a thing.

  According to this, since the light receiving direction can be directed to the direction in which the reflected light will be incident, the sensitivity of the distance measuring device can be improved. In addition, it is possible to avoid a phenomenon in which reflected light cannot be detected by other generated light.

  In order to achieve the above object, a traveling vehicle according to the present invention is projected from the light projecting means for projecting laser light and the light projecting means so that the optical axis rotates at an angle b with respect to the traveling direction. A first sweeping means for sweeping the laser light, a light receiving means for transmitting a signal when the laser light projected from the light projecting means hits an object and is reflected, and a signal from the light receiving means And a control unit that decelerates the traveling speed of the vehicle, and the angle b is 0 degree <b ≦ 10 degrees.

  According to this, since the angle at which the laser beam is projected onto the floor surface on which the traveling vehicle travels does not change, and the laser beam rotates while maintaining the angle with respect to the rotation axis constant, there are a plurality of similar traveling vehicles. Even in a factory that travels on a table, it is possible to suppress as much as possible false detections such as receiving light projected from another distance measuring device and stopping the traveling vehicle.

  In addition, since the projection angle of the laser beam is constant, when either one of the distance and the size (height) of the object is known, the other information is acquired depending on whether or not the reflected light is received. can do. For example, when the size of an object is known, it is possible to detect that the distance between the distance measuring device and the object is within a predetermined range by receiving reflected light and control the traveling vehicle. Become.

  According to the present invention, erroneous detection can be suppressed.

FIG. 1 is a perspective view schematically showing the entire distance measuring apparatus. FIG. 2 is a plan view schematically showing the distance measuring device from the side, with the distance measuring device cut away. FIG. 3 is a diagram illustrating a connection relationship between a calculation unit that performs a calculation based on a signal obtained from the distance measuring device and each component of the distance measuring device. FIG. 4A is a plan view schematically showing the traveling vehicle from the side. FIG. 4B is a plan view schematically showing the traveling vehicle from the front. FIG. 5A is a plan view schematically showing a conventional traveling vehicle from the side. FIG. 5B is a plan view schematically showing a conventional traveling vehicle from the front.

  Next, an embodiment of a distance measuring device 100 according to the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view schematically showing the entire distance measuring apparatus.

  FIG. 2 is a plan view schematically showing the distance measuring device from the side, with the distance measuring device cut away.

  As shown in the figure, the distance measuring device 100 projects laser light L, receives reflected light R reflected on an object (not shown), acquires information about the distance, and determines whether there is an obstacle or an obstacle. It is an apparatus called an obstacle sensor that acquires a distance to an object, and includes a light projecting unit 101, a first sweep unit 102, a light receiving unit 103, and a base body 104.

  The light projecting means 101 is a light source that projects the laser light L. In the case of the present embodiment, the light projecting means 101 includes a lens (not shown) so that the laser light L can be projected onto the rotation axis C, and is fixed to the bottom surface of the base body 104. The type of laser light L projected from the light projecting unit 101 is not particularly limited, but it is preferable to use infrared light in order to minimize the influence of disturbance light.

  The first sweep means 102 is an apparatus that sweeps the laser light L projected from the light projecting means 101 so that the optical axis of the laser light L rotates at an angle a with respect to the rotation axis C. In the case of the present embodiment, the first sweeping unit 102 includes a reflection unit 120 and a rotation unit 121.

  The reflection unit 120 is a mirror-like member having a reflection surface 122 that intersects the rotation axis C and reflects the laser light L projected from the light projecting unit 101. The angle of the reflection surface 122 of the reflection unit 120 is arranged such that the laser light L projected onto the rotation axis C is 80 degrees ≦ a <90 degrees with respect to the rotation axis C. The reflecting portion 120 is attached to the upper end portion of the shaft body 123, and is attached so as to rotate together with the shaft body 123 rotating around the rotation axis C and maintain the angle.

  If the angle a is 90 degrees, the possibility of receiving the reflected light R from the laser light L from another distance measuring device is increased, which is not desirable. On the other hand, when the angle is less than 80 degrees, the reflected light R cannot be obtained unless the distance between the distance measuring device 100 and the object is considerably shortened, so that the function as the distance measuring device 100 cannot be performed. From the above, it is considered that the angle a substantially selected as the distance measuring device 100 is 85 degrees ≦ a ≦ 89 degrees.

  The rotating unit 121 is a device that rotates the reflecting unit 120 around the rotation axis C in a certain direction. In the case of the present embodiment, a motor capable of rotating the cylindrical shaft 123 is employed for the rotating unit 121. The rotating part 121 is fixed to the base body 104 via a bracket 105.

  The first sweeping unit 102 reflects the laser light L projected from the light projecting unit 101 onto the rotation axis C to the reflecting surface 122 of the reflecting unit 120, whereby the laser light L can be reflected in the radial direction. Then, since the reflection unit 120 rotates about the rotation axis C without changing the incident angle of the laser light L, the laser light L is swept so as to rotate around the rotation axis C while maintaining the angle a. It becomes possible.

  The first sweep means 102 is not limited to the above embodiment. For example, instead of rotating the shaft body 123 and the reflecting portion 120 in a certain direction, the shaft body 123 and the reflecting portion 120 may be rotated and oscillated repeatedly by repeating rotation and reverse rotation. Further, the light projecting means 101 itself may be rotated or rotationally oscillated without providing the reflecting section 120.

  The light receiving unit 103 is a device that transmits a signal when the laser beam L projected from the light projecting unit 101 receives the reflected light R that is reflected when it hits an object. For example, as the light receiving means 103, an optical sensor such as a photodiode can be listed, and is appropriately adopted according to the type of the laser light L projected by the light projecting means 101. In the case of the present embodiment, the light receiving means 103 includes a lens (not shown) so that the reflected light R can be received on the rotation axis C, and is fixed to the ceiling portion of the base body 104.

  In the case of the present embodiment, the distance measuring device 100 includes the second sweep means 106. The second sweeping means 106 has the light receiving direction relative to the rotation axis C when the most sensitive direction in the visual field of the light receiving means 103 is the light receiving direction (the same direction as the reflected light R in the figure). It is a device that sweeps the light receiving direction so as to rotate at an angle a. In the case of the present embodiment, the second sweep means 106 includes a light receiving / reflecting unit 160 and a rotating unit. In the case of the present embodiment, the rotating part constituting the second sweeping means 106 is common to the rotating part 121 constituting the first sweeping means 102.

  The light receiving / reflecting unit 160 is a mirror-like member having a light receiving / reflecting surface 162 that intersects the rotation axis C and reflects the reflected light R reflected from the object. The angle of the light receiving / reflecting surface 162 of the light receiving / reflecting unit 160 is arranged such that the light receiving direction is 80 degrees ≦ a <90 degrees with respect to the rotation axis C. The light receiving / reflecting section 160 is attached to the upper end of the shaft body 123 via the reflecting section 120 so that the light receiving / reflecting section 160 rotates together with the shaft body 123 rotating around the rotation axis C and the angle can be maintained. It is attached. Since the reflected light R is scattered to some extent, the light-receiving / reflecting surface 162 may be a concave mirror that can collect the scattered light.

  As described above, since the rotating unit is shared with the first sweeping unit 102, the direction in which the laser light L is projected and the light receiving direction always coincide with each other, and thus the reflected light R reflected by the object is efficiently reflected. Light can be received well, and the sensitivity of the distance measuring device 100 can be improved.

  The second sweep means 106 is not limited to the above embodiment. For example, instead of rotating the light receiving / reflecting unit 160 in a fixed direction, rotation and reverse rotation may be repeatedly rotated around the rotation axis C. Further, the light receiving means 103 itself may be rotated or rotationally oscillated. The light receiving means 103 may receive the reflected light R coming from any direction or a limited direction with respect to the base body 104 by making the light receiving / reflecting portion 160 conical or the like.

  The base 104 is a member that serves as a basis for attaching the above-described means and members. In the case of the present embodiment, the laser light L projected by the light projecting means 101, the rotation axis C for rotating the reflecting portion 120 by the first sweeping means 102, and the light receiving direction received by the light receiving means 103 coincide with each other. Rigidity that does not deviate.

  FIG. 3 is a diagram illustrating a connection relationship between a calculation unit that performs a calculation based on a signal obtained from the distance measuring device and each component of the distance measuring device.

  The light receiving circuit 173 is a device that amplifies the signal input from the light receiving unit 103 and inputs the amplified signal to the arithmetic unit 170.

  The light projecting circuit 171 is a device that amplifies the signal input from the calculation unit 170 to a size necessary for driving the light projecting unit 101 and inputs the amplified signal to the light projecting unit 101.

  The arithmetic unit 170 is a device that can process various types of information, and is a general computer. In the present embodiment, the calculation unit 170 is a processing unit that calculates the distance to the object based on the laser light L emitted from the light projecting unit 101 and the reflected light R received by the light receiving unit 103. . Specifically, based on a distance detection algorithm that detects the distance from the phase difference between the laser light L and the reflected light R, the distance to the object located radially outside the rotation axis C is calculated. . Since the algorithm for calculating the distance from the phase difference is generally known, its description is omitted here.

  In addition, the calculation unit 170 calculates the direction of the object with respect to the base 104 and the size (width) of the object based on the rotation information obtained from the first sweep means 102.

  Here, the rotation information is the information if the rotation unit 121 is a device that can output information about the rotation angle such as a servo motor, and the information from the encoder when the encoder is provided in the shaft body 123 or the like. is there.

  The calculation unit 170 can calculate the position of the object based on the rotation information when the signal is obtained from the light receiving unit 103. It is also possible to calculate the size (width) of the object based on the timing at which a signal is obtained from the light receiving means 103, the timing at which the obtained signal cannot be obtained, and the distance from the object.

  Next, a usage mode of the distance measuring device 100 will be described based on a traveling vehicle including the distance measuring device 100 having the above-described configuration.

  FIG. 4A is a plan view schematically showing the traveling vehicle from the side.

  FIG. 4B is a plan view schematically showing the traveling vehicle from the front.

  The traveling vehicle 200 is, for example, a transport vehicle that transports articles in an automatic guided vehicle or a clean room that travels along a rail. The traveling vehicle 200 includes a control unit 201.

  The control unit 201 is a processing unit that reduces the traveling speed based on a signal from the light receiving unit 103 of the distance measuring device 100. In the case of the present embodiment, a calculation unit 170 is interposed between the distance measuring device 100 and the control unit 201, and the vehicle 200 is decelerated by a signal calculated based on a signal from the light receiving means 103. The operation of the traveling vehicle 200 is controlled such as stopping, turning, and the like.

  In addition, this invention is not limited to the said embodiment. For example, another embodiment realized by arbitrarily combining the components described in this specification may be used as an embodiment of the present invention. In addition, the present invention includes modifications obtained by making various modifications conceivable by those skilled in the art without departing from the gist of the present invention, that is, the meaning described in the claims. It is.

  Specifically, the light projecting unit 101 and the light receiving unit 103 may be attached at opposite positions. Alternatively, the distance measuring device 100 may be covered with a cover and only a limited range of the laser light L swept in the rotating state may be used. For example, the laser beam L may be projected only in the range of 90 degrees to the left and right with the traveling direction as the center. Further, it may be covered with a filter material that transmits only light in a specific wavelength range and does not transmit other light.

  Further, the arithmetic unit 170 modulates the intensity of the light in a pulse shape and measures the time difference from the signal output from the light receiving means 103, or the AM intensity modulation of the laser beam L at a certain frequency. Then, a distance detection algorithm such as an AM method for obtaining a distance from a phase difference from a received light signal or an FM method for obtaining a distance from a frequency signal of interference light by modulating the wavelength of the laser light L in the form of a triangular wave may be used. .

  The present invention can be applied to, for example, a distance measuring device mounted on an unmanned traveling vehicle or a mobile robot, an unmanned traveling vehicle, and a mobile robot.

DESCRIPTION OF SYMBOLS 100 Distance measuring device 101 Light projection means 102 First sweep means 103 Light reception means 104 Base body 105 Bracket 106 Second sweep means 120 Reflection part 121 Rotation part 122 Reflection surface 123 Shaft body 160 Light reception reflection part 162 Light reception reflection surface 170 Calculation part 171 Throw Optical circuit 173 Light receiving circuit 200 Traveling vehicle 201 Control unit

Claims (6)

A light projecting means for projecting laser light;
First sweeping means for sweeping laser light projected from the light projecting means so that the optical axis rotates at an angle a with respect to the rotation axis;
A light receiving means for transmitting a signal when the laser light projected from the light projecting means receives reflected light reflected by an object and reflected;
The angle a is a distance measuring device in which 80 degrees ≦ a <90 degrees. The first sweep means includes
A reflecting portion that has a reflecting surface that intersects the rotation axis and reflects the laser light projected from the light projecting means;
A rotation unit that rotates the reflection unit about a rotation axis;
The light projecting means is
The distance measuring device according to claim 1, wherein the reflecting surface of the reflecting portion is irradiated with laser light along a rotation axis. The first sweep means further includes
The distance measuring apparatus according to claim 2, further comprising an angle changing unit that changes an angle of the reflecting surface with respect to a rotation axis. When the most sensitive direction in the field of view of the light receiving means is the light receiving direction,
The distance measuring device according to claim 1, further comprising a second sweeping unit that sweeps the light receiving direction so that the light receiving direction rotates at the angle a with respect to the rotation axis. A light projecting means for projecting laser light;
First sweeping means for sweeping laser light projected from the light projecting means so that the optical axis rotates in a state inclined at a predetermined angle from an axis orthogonal to the rotation axis;
A distance measuring device comprising: a light receiving means for transmitting a signal when the laser light projected from the light projecting means receives reflected light reflected by an object and reflected. A light projecting means for projecting laser light;
First sweeping means for sweeping laser light projected from the light projecting means so that the optical axis rotates at an angle b with respect to the traveling direction;
A light receiving means for transmitting a signal when the laser light projected from the light projecting means receives reflected light reflected by an object and reflected;
A controller that decelerates the running speed based on a signal from the light receiving means,
The traveling vehicle in which the angle b is 0 degree <b ≦ 10 degrees.

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