JP6379628B2 - Automated guided vehicle - Google Patents

Description

  The present invention relates to travel control of an automated guided vehicle.

  2. Description of the Related Art Conventionally, automatic guided vehicles (AGVs) have been widely used as means for conveying articles in production lines and the like in factories. Self-propelled vehicles equipped with a battery are mainly used for this automatic guided vehicle, and there are operating systems that run according to a program stored in advance, or those that are comprehensively controlled by wireless communication.

  Such an automatic guided vehicle includes a power supply unit such as a battery, a drive unit that receives power from the power supply unit to generate driving force, a control unit that controls the operation of the drive unit, and a traction unit that pulls other carts, etc. Etc. are provided. The automatic guided vehicle travels by recognizing the track line affixed to the floor surface by a sensor provided in the drive unit and rotationally driving the drive wheels provided in the drive unit along the track line.

  Among the above-described automated guided vehicles that travel according to a traveling program, a technique for smoothly performing a turning operation of the automated guided vehicle is known (see, for example, “Patent Document 1”). In this technology, when the automatic guided vehicle is branched, the control unit controls the side edge of the branch guide means on the inner side in the turning direction so that the center position of the guidance sensor coincides, so that a complicated calculation operation is not required. Thus, it is possible to easily create an operation program for turning control.

JP 2011-8598 A

However, in the above-mentioned technique, there is no problem with traveling in the straight portion, but if the inner wheel is not decelerated during traveling in the curved portion, it derails from the track line, so the straight portion changes to the curved portion and the curved portion to the linear portion It was necessary to make settings on the driving program at the position. Since this setting repeats the setting change by carrying out a running trie, it takes a long trial running and setting work to obtain an optimum set value.
An object of the present invention is to solve the above-described problems and to provide an automatic guided vehicle that can accurately travel on a track line even on a curved road without troublesome settings.

The invention according to claim 1 detects a deviation amount and a deviation direction between a pair of left and right drive wheels that are rotationally driven in response to a driving force from the drive means, and a track line provided on the floor and a vehicle body reference point. detection means, have a control means for stepwise controlling the relative speed difference of each driving wheel by a plurality of control patterns depending on the shift amount, the control means when it is within the deviation amount threshold value The vehicle body reference point is returned to the track line by performing a first track correcting operation for reducing the speed of the drive wheel on the side opposite to the shift direction. When the shift amount exceeds the threshold value, the first track correction point is returned. A second trajectory correcting operation is performed to reduce the speed of the drive wheel on the shift direction side after the trajectory correcting operation, and the vehicle body reference point is returned to the trajectory line .

According to a second aspect of the present invention, in the automatic guided vehicle according to the first aspect of the present invention, the braking means further sets the speed of each of the driving wheels at a constant speed between the first track correction operation and the second track correction operation. It is characterized by performing constant speed control .

  According to the present invention, the control unit determines which of the plurality of blocks the shift amount of the automatic guided vehicle with respect to the track line corresponds, and the control unit determines the relative of each drive wheel according to the corresponding block. Since the speed difference is controlled stepwise, it is possible to provide an automatic guided vehicle that can accurately travel on a track line even on a curved road without troublesome settings.

It is a schematic front view of the automatic guided vehicle to which one Embodiment of this invention is applied. 1 is a schematic plan view of an automatic guided vehicle to which an embodiment of the present invention is applied. It is the schematic explaining the state of a track line, a detection means, and an automatic guided vehicle in one embodiment of the present invention. It is a block diagram of the vehicle control apparatus used for one Embodiment of this invention. It is a flowchart explaining the traveling control operation | movement in one Embodiment of this invention. It is a flowchart explaining the traveling control operation | movement in one Embodiment of this invention. It is a flowchart explaining the traveling control operation | movement in one Embodiment of this invention. It is a flowchart explaining the traveling control operation in other examples of one embodiment of the present invention.

  FIG. 1 is a front view of an automatic guided vehicle 1 used in an embodiment of the present invention, and FIG. 2 is a plan view thereof. This automatic guided vehicle 1 travels along a track line, which will be described later, affixed to the floor surface 2, and a method for sequentially assembling various outfitting parts to a body main body placed on the automatic guided vehicle 1 in a production line is known. . At this time, the traveling of the automatic guided vehicle is controlled by various methods. For example, the traveling of a large number of automatic guided vehicles is collectively controlled by a central controller.

  As shown in FIGS. 1 and 2, the automatic guided vehicle 1 includes a control unit 3, a traction unit 4, a drive unit 5, and a power supply unit 6. The control unit 3 includes a box-shaped frame 3 a and a traction unit. 4 is housed in the frame 4a, the drive unit 5 is housed in the frame 5a, and the power supply unit 6 is housed in the frame 6a. Each frame 3a, 4a, 5a, 6a is configured to be detachable, and each frame 3a, 4a, 5a, 6a is configured to be freely combined.

  The controller 3 controls the operation of the automatic guided vehicle 1 and includes a control plate 3b provided with a plurality of switches, monitors, and the like. The traction part 4 has an engagement part 4b with which a part of a cart or the like pulled by the automatic guided vehicle 1 is engaged. The drive unit 5 has two drive wheels 5b that are rotationally driven by a motor (not shown) whose operation is controlled by the control unit 3, and each drive wheel 5b is driven by a separate motor. The power supply unit 6 includes a battery 6 b that generates power to be supplied to the drive unit 5. A bumper 3c is provided in front of the control unit 3, and driven wheels 3d and 6c are provided below the control unit 3 and the power supply unit 6, respectively.

  A sensor 7 as a detecting means for reading the track line 8 laid on the floor surface 2 is provided on the bottom surface on the front side in the traveling direction of the drive unit 5 as shown in FIG. The sensor 7 is an 8-bit analog sensor and can always monitor the amount of deviation of the vehicle body reference point from the track line 8. In FIG. 3, only 4 bits out of 8 bits of the sensor 7 are displayed. Further, the sensor 7 is configured to be able to detect the deviation direction of the vehicle body from the track line 8 by comparing the previous position signal with the current position. In the present embodiment, the vehicle body reference point indicates the center line of the vehicle body, but is not limited thereto depending on the arrangement state of the sensor 7.

  FIG. 4 shows a vehicle control device as control means used in the present embodiment. In the figure, a vehicle control device 9 provided in the control unit 3 is a known microcomputer having a CPU, a RAM, a ROM, and the like, and controls the operation of each drive wheel 5 b in the drive unit 5. Further, the vehicle control device 9 controls the operation of each electromagnetic brake 10 provided corresponding to each drive wheel 5 b in the drive unit 5.

  Based on the above-described configuration, the track control of the automatic guided vehicle 1 will be described below. In the present invention, the state of the automatic guided vehicle 1 with respect to the track line 8 is divided into five blocks. In each block, the operation of the automatic guided vehicle 1, that is, the relative speed difference of each driving wheel 5b is determined as the driving wheel. 5b and the operation of the electromagnetic brake 10 are controlled step by step. Here, these five blocks will be described.

  First, the block “A” is a case where the sensor 7 detects a substantially center position of the track line 8 and is indicated by a state “a” in FIG. Next, the block “I” is a case where the sensor 7 detects a position deviating within a range of 5 mm or less from the center of the track line 8 and is indicated by states b and h in FIG. Next, the block “c” is a case where the sensor 7 detects a position deviated within a range of 10 mm from the center of the track line 8 and is indicated by states c and g in FIG. Next, the block “D” is a case where the sensor 7 detects a position deviating within 15 mm from the center of the track line 8 and is indicated by states d and f in FIG. Finally, the block “o” is a case where the sensor 7 detects a position deviating from the center of the track line 8 in a range exceeding 15 mm, and is indicated by a state e in FIG.

  Next, stepwise speed difference control of each drive wheel 5b by the vehicle control device 9 in each block will be described. First, in the case of the block “A”, the inner moving wheel in the detaching direction is driven at a speed 5% lower than the speed command value of the automatic guided vehicle 1, and the outer moving wheel in the detaching direction is driven at the speed command value. The off-direction here refers to a direction in which the automatic guided vehicle attempts to return from the position to the center of the track line 8 when it is deviated from the center of the track line 8. Specifically, if the automatic guided vehicle 1 is shifted to the right side from the center of the track line 8, the inside in the detaching direction indicates the left side, and the outside in the detaching direction indicates the right side.

  Next, in the case of block “I”, the inner moving wheel in the detaching direction is driven at a speed that is 10% lower than the speed command value of the automatic guided vehicle 1, and the outer moving wheel in the detaching direction is driven at the speed command value. In the case of the block “C”, the inner moving wheel in the disengagement direction is driven at a speed 20% lower than the speed command value of the automatic guided vehicle 1 and the outer moving wheel in the disengagement direction is driven at the speed command value. In the case of the block “D”, the inner moving wheel in the disengagement direction is driven at a speed that is 20% lower than the speed command value of the automatic guided vehicle 1, and the outer moving wheel in the disengagement direction is increased by 15% from the speed command value. Drive at a different speed. Finally, in the case of the block “o”, the inner moving wheel in the detaching direction is driven at a speed 50% lower than the speed command value of the automatic guided vehicle 1 and the outer moving wheel in the detaching direction is 20% lower than the speed command value. Drive at a reduced speed. A series of these control operations is referred to as a first trajectory correction operation.

  Under the above-described conditions, the travel drive control of the automatic guided vehicle 1 is performed. In the present invention, a threshold is set between the block “U” and the block “D” among the above-described blocks, and the block “A” is set. In the case of “A” and “C”, only the first trajectory correcting operation is performed, and in the case of “D” and “O”, the second trajectory correcting operation described later is performed after the first trajectory correcting operation. This is because in the case of the blocks “d” and “e” with a large deviation amount, the automatic guided vehicle 1 may exceed the track line 8 only by the first track correcting operation. Such a large deviation amount appears mainly when the automatic guided vehicle 1 travels on the curved portion of the track line 8.

  The second trajectory correcting operation performed after the first trajectory correcting operation is such that constant speed control of each drive wheel 5b is performed after the automatic guided vehicle 1 returns to the position of 1/3 from the maximum deviation amount by the first trajectory correcting operation. This is performed after the automatic guided vehicle 1 returns to the position of 2/3 from the maximum deviation amount by this constant speed control. The second trajectory correcting operation is the same for both the block “D” and the block “O”, and drives the inner moving wheel in the disengagement direction with the speed command value of the automatic guided vehicle 1 and the outer moving wheel in the disengagement direction. Is driven at a speed 20% higher than the speed command value.

Below, the driving | running | working operation | movement of the automatic guided vehicle 1 is demonstrated according to the flowchart shown in FIG.5, FIG.6, FIG.7.
When it is detected by the sensor 7 that the automatic guided vehicle 1 has deviated from the center of the track line 8, the vehicle control device 9 determines whether or not the amount of disengagement exceeds 10 mm, that is, the states d and f shown in FIG. It is determined whether or not this is the case, and if the deviation is within 10 mm, the process proceeds to step ST02 and only the first trajectory correcting operation is performed. When the deviation amount exceeds 10 mm, the process proceeds to step ST03, and the second trajectory correcting operation is performed after the first trajectory correcting operation.

  First, the case of only the first trajectory correcting operation will be described. In this example, the case where the automatic guided vehicle 1 is shifted from the track line 8 to the right side will be described. As shown in FIG. 6, when the vehicle control device 9 recognizes that the automatic guided vehicle 1 has shifted to the right side from the track line 8 (ST11), the shift amount is detected based on the signal from the sensor 7. When the deviation amount is within 5 mm (in the case of block “I”), the left driving wheel 5 b is driven 10% down from the speed command value, and when the deviation amount is within 10 mm (in the case of block “C”). ), The left driving wheel 5b is driven 20% lower than the speed command value (ST12).

  When the automatic guided vehicle 1 starts to return to the track line 8 (ST13), it is determined whether or not the state a is reached (ST14), and when the state a is reached, the left side is set so that the automatic guided vehicle 1 returns to the center of the track line 8. The drive wheel 5b is driven 5% lower than the speed command value (ST15). When it is detected that the track line 8 is in the center (ST16), the left and right drive wheels 5b are controlled at a constant speed (ST17), and the first track correcting operation is completed.

  Next, a case where the second trajectory correcting operation is performed after the first trajectory correcting operation will be described. As shown in FIG. 7, when the vehicle control device 9 recognizes that the automatic guided vehicle 1 has shifted to the right side from the track line 8 (ST21), the shift amount is detected based on the signal from the sensor 7. When the amount of deviation is within 15 mm (in the case of the block “d”), the left driving wheel 5b is driven 20% lower than the speed command value and the right driving wheel 5b is 15% lower than the speed command value. When the deviation is greater than 15 mm (when the block is “O”), the left drive wheel 5b is driven 50% lower than the speed command value and the right drive wheel 5b is the speed command value. It is driven at 20% down (ST22).

  When the automatic guided vehicle 1 starts to return with respect to the track line 8 (ST23), it is determined whether or not it has returned to the position of 1/3 from the maximum deviation (ST24). Constant speed control is performed (ST25), and the first trajectory correcting operation is completed. Next, it is determined whether or not it has returned to 2/3 of the maximum deviation (ST26). If it is determined that it has returned, the constant speed control is completed, the second trajectory correcting operation is performed, and the right drive wheel 5b is moved to the speed. It is driven 20% lower than the command value (ST27). When it is detected that the track line 8 is in the center (ST28), the left and right drive wheels 5b are controlled at a constant speed (ST29), and the second track correction operation is completed.

  In the above-described operation, an example in which the position of the automatic guided vehicle 1 is detected by the sensor 7 and it is determined whether or not the position exceeds the threshold value is shown. Next, an example in which travel control is performed according to the position of the automatic guided vehicle 1 detected by the sensor 7 will be described based on the flowchart shown in FIG. Here, the first trajectory correcting operation may be referred to as constant speed correction, and the second trajectory correcting operation may be referred to as reverse correction.

  First, the position information of the automatic guided vehicle 1 is acquired from the detection result of the sensor 7 (ST31), and the traveling direction of the automatic guided vehicle 1 is stored in comparison with the previous positional information (ST32). Next, it is determined whether or not it is within the range of the block “A” (ST33). If it is within the range, it is determined whether or not the second trajectory correction operation (reverse correction operation) storage is on (ST34). ). When it is OFF, the driving wheel 5b on the inner side in the detaching direction is driven 5% lower than the speed command value, and the driving wheel 5b on the outer side in the detaching direction is driven with the speed command value (ST35). The position information of the transport vehicle 1 is stored (ST36), and the control ends. If it is on in step ST34, the second trajectory correction operation memory is turned off (ST37), and then the process proceeds to step ST35.

  If it is out of range in step ST33, it is determined whether or not the second trajectory correcting action memory is on (ST38), and if it is off, it is determined whether or not it is in the range of the block “I”. (ST39). If it is within the range, the driving wheel 5b on the inner side in the detaching direction is driven 10% lower than the speed command value, and the driving wheel 5b on the outer side in the detaching direction is driven with the speed command value (ST40). move on. If it is outside the range in step ST39, it is determined whether or not it is within the range of the block “C” (ST41). If it is within the range, the drive wheel 5b on the inside in the off direction is 20 times higher than the speed command value. The driving wheel 5b on the outer side in the detaching direction is driven with the speed command value (ST42), and the process proceeds to step ST36.

  If it is out of range in step ST41, after the second trajectory correcting action memory is turned on (ST43), it is determined whether or not it is in the range of block “d” (ST44). If it is within the range, it is determined whether or not the automatic guided vehicle 1 is moving in a direction away from the track line 8 (ST45). If it is determined that the automatic guided vehicle 1 is not moving in a direction away from the track line 8, the process proceeds to step ST42. If it is determined that the vehicle is moving in the direction of detachment, the driving wheel 5b on the inner side in the detaching direction is driven 20% lower than the speed command value and the driving wheel 5b on the outer side in the detaching direction is 15% higher than the speed command value (ST46), the process proceeds to step ST36.

  If it is out of range in step ST44, it is determined whether or not automatic guided vehicle 1 is moving in a direction away from track 8 (ST47), and if it is determined that it is not moving in a direction away from step ST42. Proceed to If it is determined that the vehicle is moving in the direction of detachment, the driving wheel 5b on the inner side in the detaching direction is driven 50% lower than the speed command value and the driving wheel 5b on the outer side in the detaching direction is 20% lower than the speed command value (ST48), the process proceeds to step ST36.

  If it is determined in step ST38 that the second trajectory correction operation storage is turned on, it is determined whether or not the automatic guided vehicle 1 has returned from the maximum deviation by 1/3 or more by the first trajectory correction operation (ST49). If it is determined that it has not returned, it is determined whether or not the maximum deviation amount is within 15 mm (ST50). If the maximum deviation is within 15 mm, the process proceeds to step ST46, and if the maximum deviation is not within 15 mm, the process proceeds to step ST48.

  If it is determined in step ST49 that the automatic guided vehicle 1 has returned from the maximum deviation by 1/3 or more, it is determined whether or not the automatic guided vehicle 1 has returned from the maximum deviation by 2/3 or more by the second trajectory correction operation. If it is determined (ST51) that it is determined that it has not returned, each drive wheel 5b is driven with a speed command value to start constant speed control (ST52), and the process proceeds to step ST36. If it is determined that the vehicle has returned, the second trajectory correcting operation is performed to drive the driving wheel 5b on the inner side in the detaching direction with the speed command value, and the driving wheel 5b on the outer side in the detaching direction is reduced by 20% from the speed command value. (ST53), the process proceeds to step ST36.

  According to the above-described configuration, the deviation amount of the automatic guided vehicle 1 with respect to the track line 8 is determined as to which of the plurality of blocks the vehicle control device 9 corresponds, and the vehicle control device 9 determines whether the block corresponds to the corresponding block. Since the relative speed difference between the drive wheels 5b is controlled step by step, an automatic guided vehicle capable of precisely traveling on the track line 8 even on a curved road without troublesome settings is provided. be able to. In addition, since the second track correction operation is performed after the first track correction operation according to the shift amount, it is possible to prevent the automatic guided vehicle 1 from exceeding the track line 8 even when the shift amount is large. . Furthermore, since constant speed control is performed between the first track correcting operation and the second track correcting operation, the vehicle body can be quickly returned to the track line 8.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments described above, and is described in the claims unless specifically limited by the above description. Various modifications and changes can be made within the scope of the present invention. The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

DESCRIPTION OF SYMBOLS 1 Automatic guided vehicle 2 Floor 5b Drive wheel 7 Detection means (sensor)
8 Track line 9 Control means (vehicle control device)

Claims (2)

A pair of left and right drive wheels that are rotationally driven in response to a drive force from the drive means;
Detecting means for detecting the amount and direction of deviation between the track line provided on the floor and the vehicle body reference point;
Wherein possess and control means for stepwise controlling the relative speed difference of the drive wheels by a plurality of control patterns depending on the shift amount,
When the deviation amount is within a threshold value, the control means performs a first trajectory correcting operation for reducing the speed of the driving wheel on the opposite side to the deviation direction, and returns the vehicle body reference point to the trajectory line. When the threshold value is exceeded, a second trajectory correction operation is performed to reduce the speed of the drive wheel on the shift direction side after the first trajectory correction operation, and the vehicle body reference point is returned to the trajectory line. Automated guided vehicle. In the automatic guided vehicle according to claim 1,
The automatic guided vehicle is characterized in that the braking means performs constant speed control for controlling the speed of each drive wheel at a constant speed between the first track correction operation and the second track correction operation .

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