JP3975981B2 - Moving body - Google Patents

Description

  The present invention relates to a moving body provided with drive wheels on the front side and the rear side in the moving direction, and more particularly to a technique for accurately measuring the moving speed or moving distance of the moving body.

In a semiconductor manufacturing factory or the like, a movement route is laid along a processing apparatus or the like, and an automatic guided vehicle system is known in which an automatic guided vehicle is automatically traveled on the movement route and a workpiece is conveyed by the conveyance vehicle. . Such a technique is disclosed in Patent Document 1, for example, and is configured as follows.
As shown in FIG. 6, the transport vehicle 101 includes front wheels 119F and 119F and rear wheels 119R and 119R, and an encoder 117 is attached to the front wheels 119F and 119F that are drive wheels. In addition, the transport vehicle 101 includes a marker detection sensor 113 for detecting a marker attached along the movement route, and a controller 110 that controls the travel of the transport vehicle 101.
A stop marker is affixed in front of a stop position such as a station along the movement path of the transport vehicle 101, and a first inspection marker and a second inspection marker are affixed at predetermined positions on the movement path. The stop position and the stop marker are separated by a stop distance L, and the first inspection marker and the second inspection marker are separated by an inspection distance K.
With the configuration as described above, the controller 110 of the transport vehicle 101 determines the number of pulses output by the encoder 117 between the time when the marker detection sensor 113 detects the first inspection marker and the time when the second inspection marker is detected. Counting and storing this as the inspection count number Nk, and when the marker detection sensor 113 detects the stop marker, the encoder 117 newly starts counting pulses, and this count number is (L / K) · Nk. If it becomes, the conveyance vehicle 101 is stopped.

Japanese Utility Model Publication No. 5-87607

By the way, when the travel distance is measured using the encoder 117, the traveling characteristics of the transport vehicle 101 differ between when the transport vehicle 101 is accelerating and when the transport vehicle 101 is decelerating. Arise.
When the transport vehicle 101 is accelerating, the center of gravity is applied to the rear wheels with respect to the traveling direction of the transport vehicle 101, and the front wheels tend to float. When the transport vehicle 101 is decelerating, the center of gravity is applied to the front wheels with respect to the traveling direction, and the rear wheels tend to float. There is a high possibility of slippage between the rear wheel and the moving path.
For this reason, if the moving distance of the transport vehicle 101 is measured by the encoder 117 attached to the front wheels 119F and 119F, the travel obtained from the output pulse of the encoder 117 as long as the travel of the transport vehicle 101 involves acceleration / deceleration. An error occurs between the distance and the actual moving distance.
Furthermore, the transport vehicle 101 is often configured to be able to move forward and backward, and the measurement of the moving distance by the encoder 117 attached to the front wheels 119F and 119F is accurate when the vehicle approaches a stop position from the rear and decelerates. However, when the vehicle approaches the stop position from the front and decelerates, the accuracy is low, and there is a high possibility that an error has occurred with the actual moving distance.

  Therefore, in view of such a point, the present invention has an object to provide a moving body that improves the measurement accuracy of a moving speed or a moving distance with respect to a transport vehicle, a stutter crane, and other moving bodies.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

First, as described in claim 1,
A moving body having driving wheels on the front side and the rear side in the moving direction,
First rotation speed detection means for detecting the rotation speed of the driving wheel on the front side in the movement direction;
Second rotational speed detection means for detecting the rotational speed of the driving wheel on the rear side in the movement direction;
When the moving body is accelerated, the torque command value of the driving wheel on the rear side in the moving direction is made larger than the torque command value on the driving wheel on the front side in the moving direction, and when the moving body is decelerated, the torque command value of the driving wheel on the front side in the moving direction Control means for increasing the torque command value of the driving wheel on the rear side in the movement direction;
With
The control means includes
When the traveling state of the moving body is at the time of acceleration or deceleration, the number of revolutions for detecting the number of revolutions of the drive wheel having the larger distribution of the torque command value in the first revolution number detecting means or the second revolution number detecting means. Referring to the number of rotations detected by the detection means, measure the moving speed or moving distance of the moving body ,
When the traveling state of the moving body shifts from the time of acceleration or deceleration to the time of constant speed movement, the first rotational speed detection means or the second rotational speed referred to in the previous traveling state that was during acceleration or deceleration. The moving speed or moving distance of the moving body is measured with reference to the rotational speed of either one of the detecting means.

Moreover, as described in claim 2,
The control means calculates the movement distance by adding the rotation speeds referenced by the respective rotation speed detection means.

In the invention according to claim 1,
Due to the distribution of the torque command value, it is difficult for the front and rear wheels to slip.
Moreover, since the moving speed or the moving distance is measured with reference to the number of rotations of the wheel that is unlikely to slip, the measuring accuracy of the moving speed or the moving distance is improved.
In addition, the number of rotations of the rotation speed detecting means can be reduced, and the control configuration is simplified.

In the invention according to claim 2,
The control means calculates the movement distance by adding the rotation speeds referred to by the respective rotation speed detection means, so that the error between the calculated movement distance and the actual movement distance is reduced. Improved measurement accuracy.

Below, it demonstrates, referring an automatic guided vehicle system as an example of the mobile body system which concerns on this invention.
FIG. 1 shows a schematic configuration of an automatic guided vehicle system. In a clean room such as a semiconductor manufacturing factory, traveling rails 2 and 2 serving as a moving path of the automatic guided vehicle 1 are laid along the traveling rails 2 and 2. Processing devices 4, 4... Are arranged. Further, a member 20 to be detected is laid along the traveling rail 2, and the transport vehicle 1 traveling on the traveling rails 2 and 2 roughly determines the traveling position while detecting the detected member 20. It is configured to keep track of.

The detected member 20 is provided with a number of mark members 21, 21... In the moving direction of the transport vehicle 1, and each mark member 21 is a first detection sensor 11 or a second detection sensor mounted on the transport vehicle 1. A detected portion 21b that can be detected by the sensor 12 (see FIG. 4) and a non-detecting portion 21c that is not detected by the first detection sensor 11 or the second detection sensor 12 are provided.
FIG. 2 shows an example of the member 20 to be detected. The member 20 to be detected is configured in a comb-teeth shape, where the comb-tooth portion is the detected portion 21b, and the gap between the comb teeth and the comb-tooth is the non-detecting portion 21c. Thus, the width of the detected part 21b and the width of the non-detecting part 21c in the moving direction of the transport vehicle 1 are configured to be equal. In this configuration, the other end of the detected portion 21b (one end of the non-detected portion 21c) is detected from the ON signal when the first detection sensor 11 or the second detection sensor 12 of the transport vehicle 1 detects the one end of the detected portion 21b. From the OFF signal when the other end of the detected part 21b (one end of the non-detecting part 21c) is detected until the OFF signal when detected, the other end of the adjacent detected part 21b (the other end of the non-detecting part 21c) The control distance becomes simple because the distance is the same as the ON signal at the time of detection, and the movement distance can be roughly grasped by simply counting the number of ON signals and OFF signals.

Next, the transport vehicle 1 will be described.
FIG. 3 is a plan view showing the configuration of the transport vehicle 1. In the transport vehicle 1 which is a moving body, the vehicle body 1B is supported by front wheels 19F and 19F and rear wheels 19R and 19R. The transport vehicle 1 is configured by four-wheel drive to reduce slip, and drive sources 18F and 18R are attached to the front wheels 19F and 19F and the rear wheels 19R and 19R, respectively. These drive sources 18F and 18R are constituted by servo motors that can rotate forward and backward, and the transport vehicle 1 is configured to be able to move forward and backward.

  FIG. 4 shows a control configuration of the transport vehicle 1. The transport vehicle 1 is equipped with a controller 10 for controlling the travel and transfer of the load. The controller 10 includes a drive source for the front wheels 19F and 19F. A travel control unit 16F that controls 18F and a travel control unit 16R that controls the drive source 18R of the rear wheels 19R and 19R are connected by communication. Encoders 17F and 17R for measuring the moving distance of the transport vehicle 1 are attached to the drive shafts of the drive sources 18F and 18R, and the encoders 17F and 17R are connected to the controller 10 for communication. While the transport vehicle 1 is moving, the encoders 17F and 17R serving as the rotational speed detection means both detect the rotational speeds of the wheels 19F and 19F and 19R and 19R. When accelerating and traveling at a constant speed, refer to the detection value from the encoder 17R (or 17F) of the drive source 18R (or 18F) of the rear wheels 19R and 19R (or 19F and 19F) with respect to the traveling direction. When the transport vehicle 1 decelerates, the detected value from the encoder 17F (or 17R) of the drive source 18F (or 18R) of the front wheels 19F and 19F (or 19R and 19R) with respect to the traveling direction is referred to. It is configured as follows.

The reason for this is that, as shown in FIGS. 5 and 4, during acceleration, the center of gravity is applied to the rear wheels 19R and 19R (or 19F and 19F) in the traveling direction, and the front wheels 19F and 19F (or 19R / 19R) is about to float, that is, slip between the wheels 19R / 19R (or 19F / 19F) on the rear side in the moving direction and the traveling rails 2/2 causes the wheels 19F / 19F on the front side in the moving direction. Therefore, in this case, the controller 10 is a driving source for the wheels 19R and 19R (or 19F and 19F) on the rear side in the movement direction. Based on the measurement value from the encoder 17R (or 17F) of 18R (or 18F), the moving speed or moving distance is grasped.
On the other hand, at the time of deceleration, the center of gravity is applied to the front wheels 19F and 19F (or 19R and 19R) with respect to the traveling direction, and the rear wheels 19R and 19R (or 19F and 19F) try to float. That is, the slip between the wheels 19F and 19F (or 19R and 19R) on the front side in the movement direction and the traveling rails 2 and 2 causes the wheels 19R and 19R (or 19F and 19F) on the rear side in the movement direction and the traveling rails 2 and 2 to move. In this case, the controller 10 performs measurement from the encoder 17F (or 17R) of the drive source 18F (or 18R) of the wheels 19F and 19F (or 19R and 19R) on the front side in the movement direction. The movement speed or movement distance is grasped based on the value.

In this embodiment, during constant speed movement, the controller 10 performs measurement from the encoder 17R (or 17F) of the drive source 18R (or 18F) of the wheels 19R and 19R (or 19F and 19F) on the rear side in the traveling direction. The moving speed or moving distance is grasped based on the value, but from the encoder 17F (or 17R) of the drive source 18F (or 18R) of the wheel 19F / 19F (or 19R / 19R) on the front side in the traveling direction. You may comprise so that a movement speed or a movement distance may be grasped | ascertained based on this measured value.
Alternatively, the wheel encoder 17F (or 17R) referred to during the constant speed movement may be appropriately changed without being fixed. For example, the configuration is such that the reference wheel encoder 17F (or 17R) is switched only when shifting to acceleration or deceleration, and when shifting to constant speed driving, reference is made in the previous driving state (acceleration or deceleration). It is assumed that the wheel encoder 17F (or 17R) is not changed. In this configuration, when the transport vehicle 1 accelerates and then travels at a constant speed and accelerates again, or when the transport vehicle 1 decelerates and then travels at a constant speed and decelerates again, the wheel to be referred to The encoder 17F (or 17R) is not switched, the number of times the encoder 17F (or 17R) is switched can be reduced, and the control configuration is simplified.

Next, switching control of the encoder 17F / 17R will be described.
When a destination (the processing device 4 or the like) is designated in the controller 10 of the transport vehicle 1, a travel program in which acceleration / deceleration timings and the like are written is set, and travel is controlled according to the travel program.
The controller 10 serving as the control means has a magnitude of a torque command value output to the travel control unit 16F corresponding to the front wheels 19F and 19F and a torque command value output to the travel control unit 16R corresponding to the rear wheels 19R and 19R. And a switching means for switching the reference destination of the measurement data to the encoder 17F / 17R corresponding to the travel control unit 16F / 16R having the larger distribution of the torque command value based on the comparison result by the comparison means And.

  The distribution of the torque command value output from the controller 10 to each of the traveling control units 16F and 16R is performed so that the transport vehicle 1 can prevent slippage between the wheels 19F, 19F, 19R, and 19R and the traveling rails 2 and 2 as much as possible. When accelerating, the torque command value to the traveling control unit 16R (or 16F) corresponding to the wheel 19R / 19R (or 19F / 19F) on the rear side in the traveling direction on which the center of gravity is applied is set to the front wheel 19F / 19F (or 19R). 19R) is larger than the torque command value to the traveling control unit 16F (or 16R), and when the transport vehicle 1 decelerates, the front wheels 19F and 19F (or 19R and 19R) where the center of gravity is applied are applied. The torque command value to the corresponding traveling control unit 16F (or 16R) is used as the traveling control unit 16R (or 19F / 19F) corresponding to the rear wheel 19R / 19R (or 19F / 19F). The torque command value to the travel control unit 16F corresponding to the front wheels 19F and 19F and the torque command to the travel control unit 16R corresponding to the rear wheels 19R and 19R when moving at a constant speed. The value is equal.

For example, it corresponds to the torque command value to the traveling control unit 16F (or 16R) corresponding to the front wheels 19F / 19F (or 19R / 19R) and the rear wheels 19R / 19R (or 19F / 19F). The torque command value to the travel control unit 16R (or 16F) is distributed to 4 to 6 during acceleration, 6 to 4 during deceleration, and 5 to 5 during constant speed travel.
The distribution ratio of the torque values is not limited to a fixed value, and may be configured to vary based on the rotation speed from the encoder 17F or 17R.

  Before the start of travel, the controller 10 of the transport vehicle 1 creates a travel program to the destination and determines the distribution of torque command values to be output to the travel control units 16F and 16R. The magnitudes of the torque command values are compared. In the comparison means, the torque command value to the travel control unit 16R (or 16F) corresponding to the wheel 19R / 19R (or 19F / 19F) on the rear side in the movement direction is the wheel 19F / 19F (or 19R on the front side in the movement direction). 19R) is determined to be larger than the torque command value to the traveling control unit 16F (or 16R) corresponding to 19R), and in the switching means, the reference destination of the measurement data is the wheels 19R and 19R on the rear side in the movement direction (or The encoder 17R (or 17F) corresponding to 19F / 19F) is switched.

  The transport vehicle 1 starts traveling and is accelerated to a predetermined mark member 21 (first mark member 21) on the detected member 20, and the first mark is detected by the detection sensor 11 or 12 of the transport vehicle 1. When the member 21 is detected, the torque command value to the travel control unit 16F corresponding to the front wheels 19F and 19F and the torque command value to the travel control unit 16R corresponding to the rear wheels 19R and 19R are equally distributed, Travel of the transport vehicle 1 is switched to constant speed travel. This constant speed travel is performed up to a predetermined mark member 21 (second mark member 21) on the member 20 to be detected, and the controller 10 of the transport vehicle 1 moves the wheel on the rear side in the movement direction during acceleration and constant speed travel. The moving speed or moving distance is measured while referring to the encoder 17R (or 17F) corresponding to 19R / 19R (or 19F / 19F). When the second mark member 21 is detected by the detection sensor 11 or 12, the distribution of the torque command value to be output to the travel control units 16F and 16R is changed. The torque command value to the travel control unit 16F (or 16R) corresponding to 19F (or 19R / 19R) is the travel control unit 16R corresponding to the wheel 19R / 19R (or 19F / 19F) on the rear side in the movement direction. (Or 16F) is determined to be larger than the torque command value, and in the switching means, the reference destination of the measurement data is the encoder 17F (or 19R / 19R) corresponding to the wheel 19F / 19F (or 19R / 19R) on the front side in the movement direction. 17R). Thus, at the time of deceleration, the controller 10 of the transport vehicle 1 measures the moving speed or the moving distance while referring to the encoder 17F (or 17R) corresponding to the wheels 19F and 19F (or 19R and 19R) on the front side in the moving direction. Yes. The deceleration control of the transport vehicle 1 is performed so that the detection sensor 11 or 12 counts the mark members 21, 21... And the stop speed is just in line with the mark member 21 immediately before the stop target position. It is controlled. The speed immediately before the stop is a speed at which the transport vehicle 1 can stop immediately at any time. The transport vehicle 1 is located on the front side in the movement direction from the mark position on the mark member 21 immediately before the stop target position to the stop target position. The encoder 17F (or 17R) corresponding to the wheels 19F and 19F (or 19R and 19R) is accurately measured at the target stop position while measuring the moving distance from the mark position in small increments (for example, 0.01 [mm] units). Is controlled to stop.

  In the above configuration, based on the magnitude of the torque command value output from the controller 10 to the travel control units 16F and 16R, the measurement data is referred to the travel control unit 16F / 16R having a larger distribution of torque command values. The encoder 17F / 17R is configured to switch to the corresponding encoder 17F / 17R. However, the switching control of the encoder 17F / 17R is not limited to this configuration, and the controller 10 serving as a control unit is referred to by the encoder 17F or 17R. When the time change per unit time of the rotation speed is positive, it is determined as acceleration, and when the time change per unit time of the rotation speed is negative, a determination means for determining deceleration is provided, and the determination means If the acceleration is determined, the reference destination of the measurement data is the encoder corresponding to the wheel 19R / 19R (or 19F / 19F) on the rear side in the moving direction. When switching to 17R (or 17F) and it is determined that the vehicle is decelerating, the reference destination of the measurement data is switched to the encoder 17F (or 17R) corresponding to the wheel 19F / 19F (or 19R / 19R) on the front side in the moving direction, etc. It is good.

  With the configuration as described above, the controller 10 of the transport vehicle 1 switches to the encoder 17F / 17R corresponding to the wheel 19F / 19F or 19R / 19R with less possibility of slipping according to the acceleration / deceleration of the transport vehicle 1. Thus, the moving speed or moving distance is measured more accurately, and the reliability is improved.

  In the present embodiment, the transport vehicle 1 is configured to be able to roughly measure the starting distance by detecting the mark members 21, 21... Of the detected member 20 with the detection sensor 11 or 12. However, the controller 10 can also calculate the movement distance by adding the rotation speeds referred to by the encoders 17F and 17R during traveling. The error between the calculated moving distance and the actual moving distance is considerably small, and the controller 10 can measure the moving distance with high accuracy.

In the above, taking the automatic guided vehicle system as an example, the mobile body system in which the mobile body moves in the horizontal direction has been described. However, the present invention is a mobile body system in which the mobile body moves obliquely upward or obliquely downward along a slope or the like. The moving direction of the moving body is not particularly limited.
Further, the moving path of the moving body is not limited to a straight path, and may be a path including a curved portion.

The top view which shows schematic structure of an automatic guided vehicle system. The side view of the to-be-detected member 20. FIG. The top view of the conveyance vehicle 1. FIG. The block diagram which shows the control structure of the conveyance vehicle. The figure explaining the mode of acceleration / deceleration of the conveyance vehicle. The block diagram which shows the control structure of the conventional conveyance vehicle 101. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Automatic guided vehicle 2 Traveling rail 4 Processing apparatus 10 Controller 11 1st detection sensor 12 2nd detection sensor 16F Travel control part 16R Travel control part 17F Encoder 17R Encoder 18F Drive source 18R Drive source 19F Front wheel 19R Rear wheel 20 Detected member 21 Mark member 21b Detected part 21c Non-detection part

Claims (2)

A moving body having driving wheels on the front side and the rear side in the moving direction,
First rotation speed detection means for detecting the rotation speed of the driving wheel on the front side in the movement direction;
Second rotational speed detection means for detecting the rotational speed of the driving wheel on the rear side in the movement direction;
When the moving body is accelerated, the torque command value of the driving wheel on the rear side in the moving direction is made larger than the torque command value on the driving wheel on the front side in the moving direction, and when the moving body is decelerated, the torque command value of the driving wheel on the front side in the moving direction Control means for increasing the torque command value of the driving wheel on the rear side in the movement direction;
With
The control means includes
When the traveling state of the moving body is at the time of acceleration or deceleration, the number of revolutions for detecting the number of revolutions of the drive wheel having the larger distribution of the torque command value in the first revolution number detecting means or the second revolution number detecting means. Referring to the number of rotations detected by the detection means, measure the moving speed or moving distance of the moving body ,
When the traveling state of the moving body shifts from the time of acceleration or deceleration to the time of constant speed movement, the first rotational speed detection means or the second rotational speed referred to in the previous traveling state that was during acceleration or deceleration. Referring to the rotational speed of either one of the detection means, the moving speed or moving distance of the moving body is measured.
A moving object characterized by that. The control means calculates the movement distance by adding the rotation speeds referenced by the respective rotation speed detection means.
The moving body according to claim 1 .

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