JP4853744B2 - Traveling vehicle system - Google Patents

Description

  The present invention relates to a traveling vehicle system, and more particularly to preventing interference between traveling vehicles with simple control over a traveling route including a straight section and a curved section.

  Patent Document 1: Japanese Patent Application Laid-Open No. 2005-196655A discloses that a subsequent traveling vehicle receives a position and a speed from a preceding traveling vehicle and prevents interference. FIG. 7 shows a deceleration line of the following traveling vehicle for avoiding interference with the preceding traveling vehicle. For simplicity, it is assumed that the preceding traveling vehicle is stopped. The travel route includes a curve section in addition to the straight section, and the actual deceleration varies depending on the section. In order not to complicate the control, the deceleration in the representative section is used for all sections, and interference is avoided by using the value in the section with the smallest deceleration for safety. Then, a deceleration line as shown in FIG. 7 is obtained, and interference is avoided by assuming a deceleration smaller than the actual deceleration in many sections.

  The inventor paid attention to the following. The solid line in FIG. 7 shows an example of the actual deceleration pattern of the traveling vehicle, and the chained deceleration line indicates a line for starting deceleration for avoiding interference, and the vehicle is decelerated when the inter-vehicle distance becomes shorter or the speed becomes higher than this line. To start. When the vehicle starts decelerating, the vehicle decelerates more quickly than expected. Therefore, the inter-vehicle distance is longer and the vehicle speed is lower than that of the deceleration line, and the subsequent vehicle resumes acceleration. When reaching the deceleration line due to acceleration, deceleration starts again, and then acceleration starts again. Such repeated acceleration and deceleration is a waste of control. If, for example, a servo motor is used so that the vehicle can be decelerated faithfully to the deceleration line, acceleration and deceleration are not repeated, but this is a problem in terms of cost. Further, even if the common deceleration is used for all sections and the deceleration line for each section is used according to the deceleration for each section, the repetition of acceleration and deceleration can be reduced, but the control system becomes complicated.

JP2005-196655A

  An object of the present invention is to eliminate repeated acceleration and deceleration of a traveling vehicle with a simple control system in deceleration control of the traveling vehicle.

The present invention is a traveling vehicle system in which a plurality of traveling vehicles travel along a predetermined traveling route,
The travel route includes a plurality of sections with different deceleration settings for braking the motor of the traveling vehicle,
The traveling vehicle includes a traveling control unit that calculates an interference avoidance distance in order to prevent interference with a preceding traveling vehicle,
The travel control unit calculates the interference avoidance distance using the travel speed of the traveling vehicle, the maximum deceleration in the deceleration of the plurality of sections, and the body length parameter based on the length of the vehicle body, The airframe length parameter is longer than the maximum deceleration section in a section where the deceleration is smaller than the maximum deceleration. Here, the body length parameter is obtained by adding a positive margin as a margin to the vehicle body length of the traveling vehicle.

  In this invention, the traveling control unit calculates the interference avoidance distance using the traveling speed of the traveling vehicle, the maximum deceleration among the decelerations of the plurality of sections, and the body length parameter based on the length of the vehicle body. To do. Although the deceleration setting varies depending on the section, the calculation of the interference avoidance distance is performed using the maximum deceleration, so that the calculation of the interference avoidance distance becomes easy. Since the interference avoidance distance is continuously calculated repeatedly, the burden on the travel control unit can be reduced if the processing becomes easy. In addition, as shown in FIG. 7, since deceleration that is smaller than the actual deceleration in the traveling section is not assumed, it is possible to avoid repetition of deceleration and acceleration. When the interference avoidance distance is calculated using the maximum deceleration, the calculated interference avoidance distance may be too short because a larger deceleration than the actual one is used in a curve section or the like. Therefore, if the body length parameter is set longer than the maximum deceleration section in the section where the deceleration is smaller than the maximum deceleration, the interference with the preceding traveling vehicle can be prevented. For these reasons, the calculation of the interference avoidance distance is easy, the repetition of deceleration and acceleration does not occur, and interference between traveling vehicles can be prevented.

Preferably, the traveling route includes a driving wheel rail and a driven wheel rail, and the traveling vehicle includes at least three wheels including a driving wheel that moves along the driving wheel rail and a driven wheel that moves along the driven wheel rail. Prepared,
The traveling vehicle travels at the same speed in the center of the carriage with a clockwise curve and a counterclockwise curve,
The section where the maximum deceleration is a straight section,
And at least in the section where the drive wheel rail is inside the curve with respect to the driven wheel rail, the deceleration setting of the traveling vehicle is made smaller than in the straight section, and the airframe length parameter is a predetermined value compared to the straight section Just make it longer.
In this way, since the drive wheel rail is inside the curve, the interference avoidance distance can be calculated with the same deceleration as the straight section even for the section where the deceleration setting is small, and the interference with the preceding vehicle can be calculated. Can be avoided.

Particularly preferably, the travel control unit calculates the interference avoidance distance by the difference in the stop position due to the difference between the deceleration setting at least in the straight section and the deceleration setting in the section inside the curve. Extend the start position of the section inside the curve to the upstream side.
If it does in this way, the interference between the traveling vehicles in the area inside the curve can be prevented more reliably.

The top view which shows typically the layout of the traveling vehicle system of an Example The block diagram which shows the traveling system of the traveling vehicle of execution example Block diagram showing the mechanism of speed control in the embodiment The figure which shows the deceleration line in an Example The figure which shows the relationship between the position of the traveling vehicle in an Example, and a body length parameter The figure which shows the relationship between the position and speed of the preceding vehicle in an Example, and a deceleration line The figure which shows the deceleration line in the conventional example

  In the following, an optimum embodiment for carrying out the present invention will be shown.

  1 to 6 show a traveling vehicle system of the embodiment. 1 includes a driving wheel rail 6 and a driven wheel rail 8, and a guide rail may be provided in addition to this. The driving wheel rail 6 is on the outer curve section 10, the driving wheel rail 6 is on the inner curve section 11, and the other is the straight section. FIG. 1 shows curve sections 10 and 11. Reference numeral 12 denotes a traveling vehicle. For example, the pair of driving wheels 14 and 14 move along the driving wheel rail 6, and the driven wheel 16 moves on the driven wheel rail 8. The traveling vehicle 12 receives the current position and speed from the preceding traveling vehicle 12f, or in addition to these, the loaded / empty state, the traveling destination, etc., and performs speed control so as to avoid interference.

  FIG. 2 shows the structure of the traveling vehicle 12. For example, the pair of front and rear drive wheels 14, 14 are driven by the traveling motors 18, 18. The driven wheels 16 and 16 may be caster wheels, for example, and the driven wheel 16 may be a single wheel. In the control unit 20, the traveling motor 18 is controlled by the traveling control unit 21, and the map of the traveling route 4 is stored in the map storage unit 22. The contents of the map are the types of sections such as a straight section, an outer curve section, an inner curve section, the section range, that is, the position of the start point and end point of the section, and the position of a station (not shown) where the traveling vehicle 12 delivers goods. Etc. The communication unit 23 receives the position and speed of the preceding traveling vehicle, and transmits the position and speed of the own vehicle to the following traveling vehicle. Further, it communicates with a controller of the entire traveling vehicle system 2 (not shown), receives a traveling command, and reports a traveling result.

  The position on the map corresponds to the travel distance obtained from the encoder 19, in other words, the position along the drive wheel rail 6. For this reason, the travel distance on the map differs from the travel distance of the vehicle center of the traveling vehicle 12 in the curve section. In the outer curve section, the travel distance on the map is longer than the travel distance in the center of the vehicle body. The upper distance is shorter than the distance from the vehicle center. Further, the deceleration and speed input from the encoder 19 to the travel control unit 21 are smaller than the speed and deceleration at the center of the vehicle body in the inner curve section 11, and larger than the speed and deceleration at the center of the vehicle body in the outer curve section. In the straight section, the speed and deceleration input to the travel control unit 21 match the speed and deceleration at the center of the vehicle body except for the error of the encoder 19. Instead of counting the rotational speed of the traveling motor 18 with an encoder, a driven wheel (not shown) may be provided on the drive wheel rail 6 side, and the rotational speed may be counted with the encoder.

  FIG. 3 shows inputs and outputs to the traveling control unit 21. The travel control unit 21 stores the upper limit speed and the body length parameter as data for each section type, and stores the deceleration set for each section. For the calculation of the interference avoidance distance, the maximum deceleration among the decelerations set for each section is applied. The body length parameter is stored in the travel control unit 21 according to the section so that the inner curve section 11 and the outer curve section 10 are longer than the straight section and at least the inner curve section 11 is longer than the straight section. Further, the starting point of the inner curve section 11 is extended upstream from the actual starting point of the curve section. This is to avoid interference with a preceding vehicle traveling in the inner curve section.

  The travel control unit 21 receives the position and speed of the preceding vehicle from the communication unit 23, the position and speed of the host vehicle from the encoder 19, and refers to the map to which section the position of the host vehicle belongs. Determine. Which body length parameter is applied depending on the section, and the deceleration itself for calculating the deceleration line (interference avoidance distance) is common regardless of the section, and is set for each section, that is, for each section type. The maximum deceleration during deceleration. Under this condition, a deceleration line is determined so as to avoid interference with the preceding vehicle, and the traveling motor 18 is controlled so that the speed and position of the own vehicle are lower than this. If the deceleration line is obtained, the interference avoidance distance is also determined. In the control of the traveling motor 18, the deceleration set for each section is used to compensate for the fact that the deceleration is smaller than that during the calculation of the deceleration line by setting the vehicle body length for each section, that is, for each section type.

  FIG. 4 shows an example of the deceleration line in the embodiment. Here, for the sake of simplicity, it is assumed that the preceding vehicle is stopped, and the actual vehicle length of the traveling vehicle plus an appropriate margin is used as the body length parameter in the straight section. In an inner curve section or the like, a body length parameter obtained by adding a margin for compensating that the actual deceleration is smaller than the deceleration on control in the body length parameter in the straight section. The margin added in the inner curve section is the distance that the stop position shifts because the actual deceleration is smaller than the control deceleration.

  In this way, in the straight section, the traveling vehicle decelerates along the deceleration line according to the one-dot chain line in FIG. 4, and the actual deceleration and the control deceleration are equal, so that the deceleration and acceleration are not repeated. The vehicle can be stopped at a distance of the length parameter from the preceding vehicle. In the inner curve section, the deceleration line is defined as shown by the two-dot chain line in FIG. 4, but since the actual deceleration is smaller than the deceleration on control, the deceleration is delayed from the deceleration line, and the vehicle is decelerated according to the solid line. It is supplemented by adding a margin for insufficient deceleration to the long parameter, and the vehicle stops at approximately the same inter-vehicle distance as the straight section. In this case, acceleration and deceleration are not repeated. The body length parameter may be made longer for the outer curve section than for the straight section. Further, in the inner curve section, the start position of the curve section 11 is shifted upstream by at least the difference in the body length parameter from the straight section.

  FIG. 5 shows changes in the length parameter depending on the position on the travel route 4. In the travel route 4, the actual inner curve and the upstream extension are defined as the inner curve section 11, and the body length parameter in the inner curve section 11 is longer than the straight section by the margin shown in FIG. 4. The deceleration itself is common to all sections. If it is a problem in control that the body length changes suddenly when entering the inner curve section 11 from the straight section, the body length parameter may be gradually changed at the upstream entrance of the inner curve section.

  FIG. 6 shows the determination of the deceleration line in consideration of the speed of the preceding vehicle. The preceding vehicle A is stopped, and the deceleration line in this case is the same as that in FIG. 4, and a solid line is used in the straight section and a one-dot chain line is used in the inner curve section. It is assumed that the preceding vehicle B is traveling. In this case, on the assumption that the preceding vehicle B stops at a deceleration in control, the deceleration line of the following traveling vehicle is determined so as not to interfere with the preceding vehicle B. An example of a deceleration line when both the preceding vehicle and the following vehicle are in a straight section is indicated by a broken line. It is arbitrary how the effect of the speed of the preceding vehicle is reflected in the deceleration line. In addition, for the deceleration line and the body length parameter, it is arbitrary whether only the section to which the own vehicle belongs is considered or both the section to which the own vehicle belongs and the section to which the preceding vehicle belongs are considered.

In the embodiment, the following effects can be obtained.
(1) Control is simplified by making the control deceleration common to all sections.
(2) Repeated deceleration and re-acceleration can be avoided by using the maximum value during deceleration for each section type as the deceleration for control.
(3) Interference can be avoided by increasing the length parameter for the inner curve section where the actual deceleration is small.
(4) By moving the start position of the inner curve section to the upstream side, it is possible to avoid the problem that the inner curve cannot be decelerated sufficiently. That is, by increasing the interference avoidance distance at the straight line portion upstream of the actual inner curve, the vehicle can be sufficiently decelerated.
(5) Because of these, consistent control can be performed using the position, speed, deceleration, etc. on the drive wheel side, without using a servo motor and without using the position, speed, and deceleration of the center of the vehicle body. .

  In the embodiment, the traveling vehicle 12 traveling on a track is shown, but the type of traveling vehicle is arbitrary. Further, the outer curve section 10 may be controlled according to the straight section or may be controlled intermediate between the straight section and the inner curve section 11. The position of the preceding vehicle may be detected by a distance sensor instead of communication. The traveling vehicle 12 has a total of three or more wheels, and may be, for example, two driving wheels and one driven wheel, or one driving wheel and two driven wheels.

2 traveling vehicle system 4 traveling path 6 driving wheel rail 8 driven wheel rail 10 outer curve section 11 inner curve section 12 traveling vehicle 14 driving wheel 16 driven wheel 18 traveling motor 19 encoder 20 control section 21 traveling control section 22 map storage section 23 communication Part

Claims (3)

A traveling vehicle system in which a plurality of traveling vehicles travel along a predetermined traveling route,
The travel route includes a plurality of sections with different deceleration settings for braking the motor of the traveling vehicle,
The traveling vehicle includes a traveling control unit that calculates an interference avoidance distance in order to prevent interference with a preceding traveling vehicle,
The travel control unit calculates the interference avoidance distance using the travel speed of the traveling vehicle, the maximum deceleration in the deceleration of the plurality of sections, and the body length parameter based on the length of the vehicle body, The traveling vehicle system according to claim 1, wherein the body length parameter is longer in a section where the deceleration is smaller than the maximum deceleration, and longer than the maximum deceleration section. The travel path includes a driving wheel rail and a driven wheel rail, and the traveling vehicle includes a total of at least three driving wheels that move along the driving wheel rail and a driven wheel that moves along the driven wheel rail,
The traveling vehicle travels at the same speed in the center of the carriage with a clockwise curve and a counterclockwise curve,
The section where the maximum deceleration is a straight section,
And at least in the section where the drive wheel rail is inside the curve with respect to the driven wheel rail, the deceleration setting of the traveling vehicle is made smaller than in the straight section, and the airframe length parameter is a predetermined value compared to the straight section The traveling vehicle system according to claim 1, wherein the traveling vehicle system is only longer. The travel control unit calculates the interference avoidance distance by the difference between the stop position due to the difference between the deceleration setting at least in the straight section and the deceleration setting in the section inside the curve, The traveling vehicle system according to claim 2, wherein a starting position of the section is extended upstream.

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