JP2016143260A - Movement direction measurement device and self-propelled type moving body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a movement direction measurement device and self-propelled type moving body that can highly accurately measure a movement direction.SOLUTION: To a moving body (2) movable in a prescribed direction x, detection devices (9L and 9R) detecting amounts of movement xL and xR to the prescribed direction x relative to a movement surface are disposed at the left and right of the moving body with the detection devices spaced away at a prescribed distance h. When the moving body moves at a distance shorter than the prescribed distance h, an angle of deviation Δθ in a movement direction in pre and post movements of the moving body is obtained from a difference (xL-xR) between the amounts of movement detected by the left and right detection devices and the prescribed distance h. A speed of travelling bodies (5L and 5R) of the moving body (2) is modified so as to make the obtained angle of deviation Δθ small.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a moving direction measuring device and a self-propelled moving body that detect a moving direction of a moving body with respect to a moving surface.

Conventionally, self-propelled moving bodies such as electric moving shelves used for warehouses and the like that self-propelled on a floor surface to a desired target position, bleachers that can be moved electrically, unmanned carts used in factories, etc. are known. .
For example, an electric movable shelf (self-propelled movable body) is a device that reciprocates on the floor by rotating wheels by a motor, and is laid on the floor surface so that the electric movable shelf does not shift in the width direction. Independently controls the motors that drive the left and right wheels to move along the seat rail-shaped object, and the proximity sensor provided in the electric movable shelf is adjacent to the adjacent fixed shelf or the stopped electric movable shelf. When an approach is detected, the electric moving shelf that is moving is stopped (see, for example, Patent Document 1).

Japanese Patent No. 3832265 (paragraphs 0040 and 0060, FIG. 8) Japanese Patent Laid-Open No. 7-281740 (paragraphs 0015 and 0016, FIGS. 1-5)

  However, in Patent Document 1, it is necessary to lay a seat rail-like object to be detected on the floor surface so that the reciprocating moving shelf does not shift in the width direction (direction orthogonal to the moving direction). Therefore, the versatility of the place where the electric movable shelf is installed is low.

  Moreover, as a self-propelled mobile body used in an arbitrary place, there is an unmanned carriage that has a gyro and obtains a traveling direction (azimuth angle) by time-integrating angular velocity information of the gyro (for example, Patent Document 2). However, in Patent Document 2, although it is not necessary to lay the object to be detected on the floor surface, since the traveling direction is obtained from the gyro, the change in the angle of the unmanned carriage when moving on a substantially straight line However, the gyro has a problem that the traveling direction cannot be obtained accurately or the accuracy is poor. Furthermore, this problem is significant when the traveling speed of the unmanned carriage is low.

  The present invention has been made paying attention to such problems, and an object of the present invention is to provide a moving direction measuring device and a self-propelled moving body that can accurately measure the moving direction.

In order to solve the above-mentioned problem, the moving direction measuring device of the present invention comprises:
A detection device that detects movement amounts xL and xR in the predetermined direction x with respect to the moving surface is arranged on the moving body movable in the predetermined direction x at a predetermined distance h from the left and right of the moving body,
When the movable body moves a distance shorter than the predetermined distance h, the deviation Δθ in the movement direction before and after the movement of the moving body is calculated by using the difference (xL−xR) between the movement amounts detected by the left and right detection devices and the predetermined distance. It is characterized by obtaining from h.
According to this feature, the movement direction is detected with high accuracy in order to detect the movement amounts xL and xR in the predetermined direction x with respect to the moving surface when the right and left detection devices are moved by a distance shorter than the predetermined distance h. Can be measured. In particular, when moving on a substantially straight line with a small change in angle with respect to the moving direction x, the moving direction can be accurately measured.

The difference (xL−xR) between the movement amounts is obtained from the movement amounts xL and xR detected by the left and right detection devices at the same time.
According to this feature, since the left and right movement amounts xL, xR detected at the same time are used, the accuracy of the obtained movement direction is increased.

When the moving body moves a distance sufficiently shorter than the predetermined distance h, the deviation angle Δθ is obtained.
According to this feature, since the required deviation angle Δθ is sufficiently small, the value can be approximated to sin θ, and the deviation angle Δθ can be obtained accurately and quickly.

The detection device includes a laser transmitter that irradiates a moving surface with laser light, and an image sensor that reads a speckle pattern on the moving surface generated by the laser light.
According to this feature, since the speckle pattern on the moving surface generated by the laser light is read, the moving amount can be obtained with high accuracy.

The self-propelled mobile body of the present invention is
A mobile body capable of self-propelling in a predetermined direction x based on the detected position-related information,
The moving body is
A detection device which is arranged at a predetermined distance h from the left and right and detects movement amounts xL and xR in a predetermined direction x with respect to the moving surface;
The movement of the moving body so as to reduce this difference (xL-xR) from the difference (xL-xR) of the amount of movement detected by the left and right detection devices when moving a distance shorter than the predetermined distance h. And a travel control unit for correcting the direction.
According to this feature, the moving direction of the moving body is set so as to reduce the difference (xL−xR) in the moving amount when moving a distance shorter than a predetermined distance h that is an interval between the left and right detecting devices. In order to correct, the moving direction x of the moving body is corrected with high accuracy. This is particularly noticeable when moving on a substantially straight line with a small change in angle with respect to the moving direction x.

The travel control unit obtains the deviation angle Δθ in the movement direction before and after the movement of the moving body from the difference (xL−xR) of the movement amount detected by the left and right detection devices and the predetermined distance h. The moving direction is corrected based on the angle Δθ.
According to this feature, the moving direction of the moving object can be controlled based on the deviation angle Δθ. For this reason, traveling control of the moving body can be performed using parameters that do not depend on the specific shape of the moving body, such as the predetermined distance h.

The self-propelled mobile body has a traveling body on both the left and right sides, and travels in a substantially straight line,
The travel control unit is characterized in that the correction of the obtained deviation angle Δθ is adjusted by the movement amount of the left and right traveling bodies.
According to this feature, since the correction of the deviation angle Δθ is adjusted by the movement amount of the left and right traveling bodies, quick adjustment is possible.

It is explanatory drawing which looked at the movement state in the time 0 and the time 1 of the railless movement shelf in Example 1 from the upper direction. It is explanatory drawing which looked at the railless movement shelf of FIG. 1 from the front. It is a figure which shows the output signal of a movement amount detection sensor. It is a flowchart which shows operation | movement of traveling control. It is a figure which shows a driving | running | working locus | trajectory. 6 is a flowchart illustrating an operation of traveling control in the second embodiment. It is explanatory drawing which looked at the movement state in the time 0 of the railless movement shelf in Example 3, and the time 1 from the upper direction.

  EMBODIMENT OF THE INVENTION The form for implementing the railless movable shelf (movement direction measuring apparatus and self-propelled mobile body) which concerns on this invention is demonstrated below based on an Example.

  A railless movable shelf according to the first embodiment will be described with reference to FIGS. In the following description, the x direction in FIG. 1 and the depth direction in FIG. 2 are the traveling direction (front) of the railless moving shelf, and the y direction in FIGS. 1 and 2 is the left and right direction of the railless moving shelf.

  The railless movable shelf 2 has wheels (running bodies) 5L and 5R driven by servo motors 6L and 6R provided on the left and right sides so that it can run on the floor 1 in other words, that is, on the floor 1 instead of on the laid rail. It is configured to be able to run directly. The railless movable shelf 2 includes wheels 5L and 5R, servo motors 6L and 6R, a travel control unit 7, a position measurement unit 8, and movement amount detection sensors (detection devices) 9L and 9R. The upper article storage section 4 is provided with a shelf on which articles can be placed and stored.

  The movement amount detection sensors 9L and 9R are arranged at the left and right ends of the frame part 3, respectively, and laser transmitters 10L and 10R that irradiate laser light toward the floor 1, and image sensors 11L and 11R such as CCD and CMOS, respectively. It is configured. In the laser light irradiated on the floor 1, the light irregularly reflected by the minute unevenness of the floor interferes with the image plane due to the optical path difference, and a speckle pattern is generated.

  The image sensors 11L and 11R image the speckle pattern of the floor 1, and when the speckle pattern moves as the railless moving shelf 2 moves, output signals 12L and 12R corresponding to the movement amounts are output. As shown in FIG. 3, each output signal 12L, 12R is a moving pulse having a pulse number corresponding to the amount of movement in the x direction, an H, L signal indicating the positive / negative direction of movement in the x direction, and in the y direction. Movement pulses having the number of pulses corresponding to the amount of movement, and H and L signals indicating the positive and negative directions of movement in the y direction. Although FIG. 3 shows an example in which a y-direction pulse is output, the railless movable shelf 2 basically reciprocates, so that a y-direction pulse is actually output. There is almost no.

  The position measuring unit 8 receives the output signals 12L and 12R, and obtains the movement amounts of the movement amount detection sensors 9L and 9R with respect to the floor 1 in the x and y directions from the number of movement pulses and the H and L signals. Here, the above-described detection method using the speckle pattern is called a so-called laser speckle method and is a well-known method. In the first embodiment, for example, the image sensors 11L and 11R need only have a resolution of 1 mm for the amount of movement in the x and y directions to be obtained, and can be realized with a scan rate of 6000 times / second and a tracking resolution of 400 dpi, for example.

Next, measurement of the moving direction by the position measuring unit 8 will be described. As shown in FIG. 1, the coordinates (x, y, θ) of the railless moving shelf 2 at the time t = 0, the coordinates (xL0, yL0) of the centers of the movement amount detection sensors 9L, 9R, (xR0, yR0) is moved to coordinates (x ′, y ′, θ ′), (xL1, yL1), (xR1, yR1) at time t = 1, respectively. Further, the moving direction A at the center of the railless moving shelf 2 changes its direction by the deviation angle Δθ at time t = 1.
The movement amounts of the movement amount detection sensors 9L and 9R in the x direction are xL (= √ ((xL1−xL0) ² + (yL1−yL0) ² )), xR (= √ ((xR1−xR0) ² + (yR1− yR0) ² ), and the difference is obtained as xL−xR.

The declination Δθ can be expressed by Equation 1 from the geometrical relationship.
sin Δθ = (xL−xR) / h (Equation 1)
Here, since the left-right width (width in the y direction) of the railless movable shelf 2 is long and the distance h between the movement amount detection sensors 9L and 9R is sufficiently longer than the difference xL-xR, sin Δθ is Δθ as shown in Equation 2. Can be approximated. For example, h = 3600 mm and xL-xR = 5 mm, and h is sufficiently longer than xL-xR.
sin Δθ≈Δθ (Expression 2)
Therefore, the moving direction A at time t = 1 can be obtained as θ + (xL−xR) / h as θ + Δθ.

Next, traveling control in the moving direction of the railless moving shelf 2 will be described with reference to FIG.
Although the railless movable shelf 2 reciprocates, the movement direction may be swung as shown in FIG. 1 due to dirt, bumps or the like of the floor 1, and the movement direction A (θ) is detected by detecting this turn. Must be oriented in the x direction.

The position measuring unit 8 increments the variable n (step 1) and outputs the movement amounts xLn and xRn of the movement amount detection sensors 9L and 9R in the x direction and the deviation angle Δθ of the movement direction of the railless moving body 2 (step 2). ). Note that the initial value of n is 0.
The traveling control unit 7 compares the deviation angle Δθ with a predetermined value k (for example, 0.001) (step 3), and if it is larger than the predetermined value k, it is determined that the moving direction A has changed to the right. The right servo motor 6R is corrected to increase in speed relative to the left servo motor 6L so as to cancel the angle Δθ (step 4).

When step 3 is negative, the declination angle Δθ is compared with a predetermined value −k (for example, −0.001) (step 5), and when smaller than the predetermined value −k, the moving direction A changes to the left. If so, the left servo motor 6L is corrected to increase in speed relative to the right servo motor 6R so as to cancel the deviation angle Δθ (step 6).
When step 6 is negative, since the railless movable shelf 2 is moving straight, it is not necessary to correct the speed of the left and right servomotors 6L and 6R.
In this way, the deviation angle Δθ is corrected as shown in FIG. 5, for example, and the railless movable shelf 2 can be moved straight. In addition to the above, a process may be added in which the movement amounts yLn and yRn in the y direction based on the detection of skid are obtained, and the servo motors 6L and 6R are controlled so that the movement amounts in the y direction return to y ′ = y. .

  Here, the calculation time (cycle) of the deflection angle Δθ will be described. The deviation angle Δθ is not greatly deviated in the y direction if it is calculated when the distance is shorter than the predetermined distance h, preferably when the distance is sufficiently short. The sufficiently small value is 1/10, more preferably 1/100. In other words, depending on the allowable error range, the value of sin Δθ can be approximated to Δθ by Equation 2. For example, when the error is within 1% from the value of sin, Δθ should be within 2 °, and the calculation time can be obtained from the moving speed of the moving shelf 2 and the distance h. For example, assuming that h = 3600 mm and the railless moving shelf 2 moves 5 m / min, if approximately every second is calculated, Δθ is 0.06 ° even if one of the servo motors 6L and 6R fails and stops and turns. (This is an angle that is much smaller than 2 °). Therefore, when the speed correction of the left and right servomotors 6L and 6R is performed, there is almost no deviation in the y direction, and as described above, only the deviation angle Δθ is obtained. It is possible to keep going straight by correcting.

As described above, since the movement amounts xL and xR in the predetermined direction x with respect to the moving surface are detected when the movement amount detection sensors 9L and 9R are moved by a distance shorter than the predetermined distance h that is an interval between the movement amount detection sensors 9L and 9R. The moving direction can be measured well. In particular, the railless moving shelf 2 moves on a substantially straight line with a small change in angle with respect to the moving direction x, and since the moving speed is low, the moving direction can be accurately measured. it can. In other words, it is particularly preferable to adopt the one that moves on a substantially straight line or one that moves at a low speed.
In addition, unlike the case of obtaining the moving direction based on the known speed difference between the left and right wheels, there is no slip between the wheel and the floor, so the accuracy is good.

Moreover, since the left and right movement amounts xL and xR detected at the same time are used, the accuracy of the obtained movement direction is increased.
Further, since the required deflection angle Δθ is small, the value can be approximated to sin θ, and the deflection angle can be obtained accurately and quickly.
Further, since the speckle pattern on the moving surface generated by the laser beam is read, the moving amount can be obtained with high accuracy.
Further, since the moving direction A is corrected by the deviation angle Δθ, it is possible to control the moving body with parameters k and −k that do not depend on the specific shape of the moving body such as the predetermined distance h.

  Next, a railless movable shelf according to the second embodiment will be described with reference to FIG. In addition, the same structure as the said Example 1 and the overlapping structure are abbreviate | omitted. In the first embodiment, an example in which the deflection angle Δθ is obtained and the speeds of the left and right servomotors 6L and 6R are corrected according to the deflection angle Δθ has been described. However, as illustrated in FIG. The speed of the left and right servomotors 6L and 6R may be corrected by obtaining the difference xLn−xRn and comparing the difference with predetermined values m and −m.

  Next, a railless movable shelf according to the third embodiment will be described with reference to FIG. In addition, the same structure as the said Example 1 and the overlapping structure are abbreviate | omitted. In the first embodiment, the example in which the position measurement unit 8 obtains the movement direction A has been described. However, in addition to the movement direction, the two-dimensional positions x, y, and θ may be obtained.

  FIG. 7 is a diagram for explaining that the railless moving shelf 2 moves from time t = 0 to time t = 1 as in FIG. 1. In addition to FIG. 1, the turning center O and the radius r are shown. Yes. The moving distance of the railless moving shelf 2 is the moving distance in the x direction as described above. When this operation is approximated as a rotational motion, the two-dimensional positions x ′, y ′, and θ ′ of the railless movable shelf 2 after a lapse of a minute time are expressed as follows using the music coordinates.

Δθ = (xL−xR) / h (Equation 3)
r = −xR / θ (Expression 4)
x ′ = x−r · sin θ + r · sin (θ + Δθ) (Equation 5)
y ′ = y−r · cos θ + r · cos (θ + Δθ) (Equation 6)
θ ′ = θ + Δθ (Expression 7)

  Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to these embodiments, and modifications and additions within the scope of the present invention are included in the present invention. It is.

  In the above-described embodiment, the railless moving shelf is described as an example of the self-propelled moving body. However, the self-propelled moving body is not limited thereto, and may be a self-propelled automatic guided vehicle, a self-propelled robot, a moving bleacher, or the like. In particular, from the viewpoint that the moving direction can be accurately obtained, a moving body that moves on a substantially straight line and a moving body that moves slowly are preferable.

  Further, although the movement amount detection sensors 9L and 9R have the laser transmitters 10L and 10R and the image sensors 11L and 11R and detect the speckle pattern as an example, a digital image captured by the imaging device is described. And the amount of movement may be detected by an image correlation method.

  Further, the description has been made on the assumption that the wheels 5L and 5R do not slip sideways. However, when a side slip occurs, the same amount of movement distance in the y direction is output from both the movement amount detection sensors 9L and 9R. Can be determined. The traveling body may be other than wheels such as an endless track.

2 Railless movable shelf (self-propelled movable body)
3 Frame part 4 Article accommodating part 5L, 5R Wheel (running body)
6L, 6R Servo motor 7 Travel control unit 8 Position measurement unit 9L, 9R Movement amount detection sensor (detection device)
10L, 10R Laser transmitters 11L, 11R Image sensor A Movement direction h Predetermined distance Δθ Declination

Claims (7)

A detection device that detects movement amounts xL and xR in the predetermined direction x with respect to the moving surface is arranged on the moving body movable in the predetermined direction x at a predetermined distance h from the left and right of the moving body,
When the movable body moves a distance shorter than the predetermined distance h, the deviation Δθ in the movement direction before and after the movement of the moving body is calculated by using the difference (xL−xR) between the movement amounts detected by the left and right detection devices and the predetermined distance. A moving direction measuring device obtained from h.   The movement direction measuring apparatus according to claim 1, wherein the difference (xL-xR) between the movement amounts is obtained from movement amounts xL and xR detected by the right and left detection devices at the same time.   3. The moving direction measuring apparatus according to claim 1, wherein the deviation angle Δθ is obtained when the moving body moves a distance sufficiently shorter than the predetermined distance h.   The said detection apparatus has a laser transmitter which irradiates a moving surface with a laser beam, and an image sensor which reads the speckle pattern of the moving surface produced by the said laser beam. The moving direction measuring device according to 1. A mobile body capable of self-propelling in a predetermined direction x based on the detected position-related information,
The moving body is
A detection device which is arranged at a predetermined distance h from the left and right and detects movement amounts xL and xR in a predetermined direction x with respect to the moving surface;
The movement of the moving body so as to reduce this difference (xL-xR) from the difference (xL-xR) of the amount of movement detected by the left and right detection devices when moving a distance shorter than the predetermined distance h. A self-propelled mobile body comprising a travel control unit that corrects a direction.   The travel control unit obtains the deviation angle Δθ in the movement direction before and after the movement of the moving body from the difference (xL−xR) of the movement amount detected by the left and right detection devices and the predetermined distance h. The self-propelled mobile body according to claim 5, wherein the moving direction is corrected based on an angle Δθ. The self-propelled mobile body has a traveling body on both the left and right sides, and travels in a substantially straight line,
The self-propelled mobile body according to claim 5 or 6, wherein the travel control unit adjusts the correction of the obtained deviation angle Δθ by a movement amount of the left and right travel bodies.

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