JP4683143B2 - Transport vehicle - Google Patents

Description

  The present invention relates to a transport vehicle, and more particularly, to a transport vehicle in which motors are separately provided on left and right wheels and the wheels can be driven independently.

  2. Description of the Related Art A transport vehicle for transporting a large glass substrate or a cassette in which a plurality of glass substrates are stored is known. The transport vehicle automatically travels in a clean room in the factory and transports articles between processing devices.

  The track on which the transport vehicle travels is, for example, a rail suspended from the ceiling. In this case, the space in which the rail and the transport vehicle travel is a clean room that is blocked from the outside.

  The conveyance vehicle has wheels on both the left and right sides. A motor is connected to one wheel to form a driving wheel, and the other wheel serves as a driven wheel. The transport vehicle further includes guide rollers that contact the left and right guide rails.

  The driving wheel is driven by servo control, and a technique is known in which a travel control unit performs PID control or PD control of a motor (see, for example, Patent Document 1). For example, when PID control is used, motor control that follows the command speed is performed even for load fluctuations due to disturbance.

JP 2000-298518 A

  2. Description of the Related Art A transport vehicle is known that can be driven independently using left and right wheels as drive wheels by providing separate motors for left and right wheels, respectively. In this case, since the left and right wheels cannot be synchronized completely, stable driving is realized by PID control of the left and right drive wheels. However, when the drive wheels on both sides are PID controlled, there is a problem that the running behavior of the transport vehicle becomes unstable if the left and right torque balance is disturbed even a little. In particular, the traveling behavior tends to be disturbed when the transport vehicle decelerates and stops.

  An object of the present invention is to realize stabilization of traveling behavior in a transport vehicle in which motors are separately provided on left and right wheels and the wheels can be driven independently.

A transport vehicle according to an aspect of the present invention includes a vehicle body, left and right first traveling wheels and second traveling wheels, a first motor and a second motor, a first control unit, and a second control unit. Yes. The first traveling wheel and the second traveling wheel are provided on the vehicle body. The first motor and the second motor are connected to the first traveling wheel and the second traveling wheel, respectively. The first control unit performs PID control of the first motor. The second control unit can switch between PID control and feedback control not including a differential element in order to control the second motor.
In this transport vehicle, when the first motor is PID-controlled, the second control unit can perform feedback control of the second motor that does not include a differential element. At this time, in the second motor and the second traveling wheel, the response performance to disturbance is reduced. Thereby, even if the response performance with respect to the disturbance remains high on the first motor and the first traveling wheel side, the second traveling wheel follows it, and the traveling of the entire transport vehicle is hardly adversely affected. In this way, the traveling behavior of the transport vehicle is stabilized.

A transport vehicle according to another aspect of the present invention is a transport vehicle that travels along a travel surface and a guide rail, and includes a vehicle body, a pair of bogies, a first motor and a second motor, and a first control unit. And a second control unit. The pair of bogies is provided on the front and rear of the vehicle body, and includes left and right first traveling wheels and second traveling wheels mounted on a traveling surface, and guide rollers supported by guide rails. The first motor and the second motor are respectively connected to a first traveling wheel and a second traveling wheel provided on at least one of the pair of bogies. The first control unit performs PID control of the first motor. The second control unit can switch between PID control and feedback control not including a differential element in order to control the second motor.
In this transport vehicle, when the first motor is PID-controlled, the second control unit can perform feedback control of the second motor that does not include a differential element. At this time, in the second motor and the second traveling wheel, the response performance to disturbance is reduced. Thereby, even if the response performance to the disturbance remains high on the first traveling wheel side, the second traveling wheel follows it, and it is difficult to adversely affect the traveling of the entire transport vehicle. In this way, the traveling behavior of the transport vehicle is stabilized.
Furthermore, since the transport vehicle is supported by the guide rail, unstable operation caused by disturbance is unlikely to occur on the second motor and second traveling wheel side.

The second control unit may perform PID control when the traveling speed of the transport vehicle is equal to or higher than a predetermined speed, and may perform feedback control that does not include a differential element when the traveling speed is lower than the predetermined speed.
In this transport vehicle, for example, during a positioning operation after deceleration control, the first control unit can execute PID control, and the second control unit can execute feedback control that does not include a differential element. Accordingly, by performing PID control of both motors during normal traveling of the transport vehicle, the response performance to disturbances in the entire transport vehicle can be improved, and the travel behavior of the transport vehicle can be stabilized during low speed travel of the transport vehicle. .

The second control unit performs PID control in a region where the inner and outer wheel speed difference changes when the transport vehicle runs in a curve, and executes feedback control that does not include a differential element in a region where the inner and outer wheel speed difference is constant. Good.
In this transport vehicle, the first control unit can perform PID control and the second control unit can perform feedback control that does not include a differential element in a region where the inner and outer wheel speed difference is constant during curve traveling. Thus, by performing PID control of both motors during normal travel of the transport vehicle, the response performance to disturbances in the entire transport vehicle can be improved, and the travel behavior of the transport vehicle can be stabilized during curving travel of the transport vehicle. .

  In the transport vehicle according to the present invention, the driving behavior is stabilized when the motors are separately provided on the left and right wheels and the wheels can be driven independently.

The schematic diagram of the conveyance vehicle system by which one Embodiment of this invention was employ | adopted. The partial top view of a conveyance vehicle system. The block block diagram which shows the control structure of a conveyance vehicle system. The block block diagram which shows the traveling control part of a conveyance vehicle. The graph which shows the relationship between the distance and speed of stop operation. Speed ratio table when driving on a curve.

(1) Transportation vehicle system The conveyance vehicle system 1 by which one Embodiment of this invention was employ | adopted is demonstrated using FIG. FIG. 1 is a schematic diagram of a transport vehicle system in which an embodiment of the present invention is adopted.

  The transport vehicle system 1 includes a track 2 and a transport vehicle 3 that travels on the track 2. In this embodiment, the track 2 is suspended from the ceiling, and the periphery of the track 2 is a clean room.

  The track 2 has a traveling rail 4 and a guide rail 6. The traveling rail 4 is composed of left and right first traveling rails 4a and second traveling rails 4b. The first traveling rail 4a and the second traveling rail 4b have flat traveling surfaces.

  The guide rail 6 has a first guide rail 6a and a second guide rail 6b. The first guide rail 6a and the second guide rail 6b are provided at the outer ends of the first travel rail 4a and the second travel rail 4b, respectively. The first guide rail 6a and the second guide rail 6b extend upward.

  A power supply line (not shown) is provided along the first traveling rail 4a and the second traveling rail 4b.

  As shown in FIG. 2, the track 2 includes a straight portion 7, a branch portion 9, a curved portion 8 that bends to the right from the branch portion 9, and a second portion 7 a that extends straight from the branch portion 9. ing.

  The first traveling rail 4a and the second traveling rail 4b extend separately in both a curved portion 8 and a branch portion 9.

In the curved portion 8, the first guide rail 6a is formed continuously, but the second guide rail 6b is partially interrupted.
In the second portion 7a, the second guide rail 6b is formed continuously, but a part of the first guide rail 6a is interrupted.

  In this embodiment, the branching portion 9 refers to the entire portion including a part of the straight line portion 7 and the curved portion 8, and the point where the branching is started is referred to as a branching point 9a.

A plurality of types of detected parts provided along the traveling rail 4 will be described with reference to FIG. The detected part includes a reflective tape 11, a barcode 13, and a magnetic mark 14. In FIG. 2, the reflective tape 11, the barcode 13, and the magnetic mark 14 are illustrated inside the traveling rail 4, but are actually provided on the traveling rail 4.
The reflective tape 11 is a member for detecting the position of the transport vehicle 3 in the curved portion 8, and is disposed in the curved portion 8 in the drawing.
The bar code 13 functions as an origin mark and a plurality of reference marks of the traveling rail 4.
The magnetic mark 14 is a member that indicates the stop position of the transport vehicle 3. The magnetic mark 14 is made of a magnetic material such as steel or a diamagnetic material such as copper or aluminum. In this embodiment, the magnetic mark 14 is disposed on the straight line portion 7, and the stop position 80 is in the middle of the magnetic mark 14.

(2) Transport Vehicle The transport vehicle 3 includes a transport vehicle main body 15, a drive travel unit 18, and a driven travel unit 19. Since the structure of the transport vehicle body 15 is the same as the conventional one, the description thereof is omitted. The drive travel unit 18 and the driven travel unit 19 are bogies that are rotatably attached to the transport vehicle body 15.

  The drive travel unit 18 will be described with reference to FIG. The drive travel unit 18 mainly includes a main body frame 20, a first drive wheel unit 21, a second drive wheel unit 22, a fixed guide roller mechanism, and a branch guide roller mechanism.

  The first drive wheel unit 21 is attached to the right end portion of the main body frame 20 and includes a first drive wheel 25, a first motor 26, and a first encoder 27. The first drive wheels 25 are placed on the travel surface of the first travel rail 4a. The first motor 26 is connected to the first drive wheel 25. The first encoder 27 measures the rotation of the first motor 26 and transmits a pulse signal. Thereby, the rotation speed and the number of rotations of the first motor 26 can be obtained.

  The second drive wheel unit 22 is attached to the left end portion of the main body frame 20 and has a second drive wheel 28, a second motor 29, and a second encoder 30. The second drive wheels 28 are placed on the travel surface of the second travel rail 4b. The second motor 29 is connected to the second drive wheel 28. The second encoder 30 measures the rotation of the second motor 29 and transmits a pulse signal. Thereby, the rotation speed and the number of rotations of the second motor 29 can be obtained.

  The fixed guide roller mechanism has a pair of first fixed guide rollers 31 and a pair of second fixed guide rollers 32. The pair of first fixed guide rollers 31 are disposed at the right end portion of the main body frame 20 so as to be separated from each other in the traveling direction. More specifically, the first fixed guide roller 31 is disposed away from both the front and rear sides of the first drive wheel 25 in the traveling direction, and is always in contact with or close to the inner side of the first guide rail 6a. The pair of second fixed guide rollers 32 are disposed at the left end portion of the main body frame 20 so as to be separated from each other in the traveling direction. More specifically, the second fixed guide roller 32 is disposed away from both the front and rear sides of the second drive wheel 28 in the traveling direction, and is always in contact with or close to the inner side of the second guide rail 6b.

  The branching guide roller mechanism is a mechanism for performing a branching operation in the branching section 9, and a pair of first branching guide rollers 33, a second branching guide roller 34, and a first branching guide roller driving unit 35 (FIG. 3). And have.

  The first branch guide roller 33 is disposed corresponding to the first fixed guide roller 31. The second branch guide roller 34 is disposed corresponding to the second fixed guide roller 32. The first branch guide roller driving unit 35 (FIG. 3) is a mechanism for changing the positions of the first branch guide roller 33 and the second branch guide roller 34.

  With the above structure, the first branch guide roller 33 and the second branch guide roller 34 are in contact with or close to the outside of the first guide rail 6a by the first branch guide roller driving unit 35 (FIG. 3), It moves between a non-guide position away from the first guide rail 6a.

The driven section 19 mainly includes a main body frame 23, a first driven wheel 36, a second driven wheel 37, a second fixed guide roller mechanism, and a second branch guide roller mechanism.
The first driven wheel 36 is placed on the first traveling rail 4 a of the traveling rail 4. The second driven wheel 37 is placed on the second traveling rail 4 b of the traveling rail 4.

  The second fixed guide roller mechanism has a pair of third fixed guide rollers 40 and a pair of fourth fixed guide rollers 41. The third fixed guide roller 40 is disposed at the right end of the main body frame 23 so as to be separated in the traveling direction. More specifically, the third fixed guide roller 40 is disposed away from both the front and rear sides in the traveling direction of the first driven wheel 36, and is always in contact with or close to the inner side of the first guide rail 6a. The fourth fixed guide roller 41 is arranged at the left end of the main body frame 23 so as to be separated in the traveling direction. More specifically, the fourth fixed guide roller 41 is disposed away from both the front and rear sides of the second driven wheel 37 in the traveling direction, and is always in contact with or close to the inner side of the second guide rail 6b.

  The branching guide roller mechanism is a mechanism for performing a branching operation in the branching section 9, and a pair of third branching guide rollers 42, a fourth branching guide roller 43, and a second branching guide roller driving unit 44 (FIG. 3). And have.

  The first branch guide roller 33 is disposed corresponding to the first fixed guide roller 31. The second branch guide roller 34 is disposed corresponding to the second fixed guide roller 32. The second branch guide roller drive unit 44 (FIG. 3) is a mechanism for changing the positions of the first branch guide roller 33 and the second branch guide roller 34.

With the above structure, the second branch guide roller driving unit 44 (FIG. 3) causes the third branch guide roller 42 and the fourth branch guide roller 43 to abut or approach the outside of the first guide rail 6a; It moves between a non-guide position away from the first guide rail 6a.
(3) Sensor and Detected Section The driving traveling section 18 and the driven traveling section 19 are further provided with a photoelectric sensor 47, a linear scale 49, and a barcode reader 50 as shown in FIG. The photoelectric sensor 47 is for detecting the reflective tape 11. The linear scale 49 is for detecting the magnetic mark 14. The linear scale 49 obtains the absolute position of the transport vehicle 3 with respect to the magnetic mark 14, in other words, the position based on the magnetic mark 14. The barcode reader 50 is for detecting the barcode 13.

(4) Control Configuration The control configuration of the transport vehicle system 1 will be described with reference to FIG. FIG. 3 is a block diagram showing a control configuration of the transport vehicle system.

  The transport vehicle system 1 includes a transport vehicle controller 52. The transport vehicle controller 52 is a controller for managing the traveling of the plurality of transport vehicles 3. The transport vehicle controller 52 and the transport vehicle 3 can communicate with each other. The transport vehicle controller 52 includes a controller main body 54 and a first memory 55. The controller main body 54 is a computer that includes a CPU, a RAM, a ROM, and the like and executes a program. In the first memory 55, a route map is stored.

  The route map is a map that describes the arrangement of the travel route, the position of the origin, the reference position based on the origin, and the coordinates of the transfer position. The coordinates are obtained by converting the travel distance from the origin into the number of output pulses of the encoder of the transport vehicle.

  The transport vehicle 3 has a travel control unit 59. The travel control unit 59 can transmit a drive signal to the first motor 26 and the second motor 29 based on a command from the transport vehicle controller 52. The travel control unit 59 is further connected to the branch control unit 60. The branch control unit 60 can transmit a drive signal to the first branch guide roller driving unit 35 and the second branch guide roller driving unit 44 (FIG. 3) based on a command from the transport vehicle controller 52.

(5) Travel control system of conveyance vehicle The travel control unit 59 will be described with reference to FIG. FIG. 4 is a block diagram illustrating a travel control unit of the transport vehicle.
The travel control unit 59 is a computer that includes a CPU, a RAM, a ROM, and the like and executes a program. The travel control unit 59 includes a route map 61, a speed pattern generation unit 62, a first motor control unit 63, and a second motor control unit 64. Have.

Furthermore, the first encoder 27, the second encoder 30, the photoelectric sensor 47, the linear scale 49, and the barcode reader 50 are connected to the travel control unit 59.
The route map 61 is stored in a memory in the travel control unit 59. The speed pattern generation unit 62 can communicate with the transport vehicle controller 52.

  When the travel control unit 59 receives a transport command from the transport vehicle controller 52, the travel control unit 59 obtains a distance from the current position to the stop position based on the route map 61 and inputs the distance to the speed pattern generation unit 62. The speed pattern generator 62 calculates a travel distance from the difference between the coordinates of the current position on the route map 61 and the coordinates of the target position, thereby generating a travel speed pattern. The speed pattern generation unit 62 generates a speed pattern for traveling to the stop position.

  The first motor control unit 63 mainly includes a first error amplification unit 65A, a first PID control unit 66A, and a first amplifier 67A. The first error amplifier 65A amplifies the error. The first PID control unit 66A performs PID control based on the error obtained by the first error amplification unit 65A. The first amplifier 67A performs current amplification for the first motor 26 and the like. The first encoder 27 detects the rotational speed of the rotation shaft of the first motor 26, and the current position and speed of the first driving wheel 25 obtained thereby are input to the speed pattern generation unit 62 and the first error amplification unit 65A. .

The second motor control unit 64 mainly includes a second error amplification unit 65B, a second PID control unit 66B, a second amplifier 67B, and a PI control unit 68. The second error amplifying unit 65B amplifies the error. The second PID control unit 66B performs PID control based on the error obtained by the second error amplification unit 65B. The PI control unit 68 is arranged in parallel with the second PID control unit 66B, and performs PI control based on the error obtained by the second error amplification unit 65B. The second amplifier 67B performs current amplification for the second motor 29 and the like. The second encoder 30 detects the rotational speed of the rotation shaft of the second motor 29, and the current position and speed of the second drive wheel 28 obtained thereby are input to the speed pattern generation unit 62 and the second error amplification unit 65B. .
With the configuration described above, the transport vehicle 3 continues traveling while comparing the coordinates described in the route map 61 with the internal coordinates of the own machine (coordinates obtained by the encoder).

(6) Normal Travel Control Operation The transport vehicle 3 performs travel control along the track 2 based on the required travel distance obtained from the route map 61, the current position obtained from the first encoder 27 and the second encoder 30, and the current speed. Do.
At this time, the first PID control unit 66A and the second PID control unit 66B perform PID control on the first motor 26 and the second motor 29, respectively, thereby realizing a preferable traveling operation.

(7) Stop Control Operation Next, the operation when the transport vehicle 3 reaches the stop position 80 will be described with reference to FIG. FIG. 5 is a graph showing the relationship between the stop operation distance of the transport vehicle 3 and the speed. When the transport vehicle 3 stops, there is generally a problem that the behavior becomes unstable due to the bogie cart swinging due to the slow speed state. The present invention uses the following means for solving the problem.

  When the transport vehicle 3 approaches the stop position 80, the speed pattern generation unit 62 sends a deceleration command to the first error amplification unit 65A and the second error amplification unit 65B based on the travel position information obtained by the encoder or other sensor. Send. Thereby, the speed of the conveyance vehicle 3 decreases as shown in FIG.

Eventually, when the transport vehicle 3 reaches the magnetic mark 14, the linear scale 49 obtains the absolute position of the transport vehicle 3 with respect to the magnetic mark 14 and inputs it to the speed pattern generator 62.
When the linear scale 49 detects the magnetic mark 14, the following two types of control operations are executed. Note that these control operations do not have to be started simultaneously.
1) The speed pattern generation unit 62 transmits a position command targeting the position to the first error amplification unit 65A and the second error amplification unit 65B instead of the speed command targeting the speed.
2) In the second motor control unit 64, the second PID control unit 66B stops the control operation, and the PI control unit 68 starts feedback control instead. On the other hand, in the first motor control unit 63, the first PID control unit 66 </ b> A performs feedback control for the first motor 26. That is, during low speed travel, the first motor 26 is PID-controlled and the second motor 29 is PI-controlled.

While the first motor 26 is PID-controlled during the low-speed running described above, the second motor 29 is controlled without including a differential element, so the second motor 29 and the second drive wheel 28 respond to disturbances. Performance decreases. Thereby, even if the response performance with respect to the disturbance remains high on the first motor 26 and the first drive wheel 25 side, the second drive wheel 28 follows it, and the traveling of the entire transport vehicle 3 is hardly adversely affected. In this way, the traveling behavior is stabilized particularly when the transport vehicle 3 is stopped.
In particular, although the driving traveling unit 18 and the driven traveling unit 19 are bogies, the bogies are less likely to swing.

(8) Curved part traveling A control operation when the transport vehicle 3 travels the curved part 8 will be described. When traveling on the curved portion 8, generally, the left and right motors cannot be perfectly synchronized, so that the travel locus does not match the actual curve rail and the traveling wheel collides with the guide rail. There is a problem that the behavior becomes unstable. The present invention uses the following means for solving the problem.

  The speed pattern generation unit 62 confirms the current position of the transport vehicle 3 by collating the detection results from the photoelectric sensor 47 and the detection results from the first encoder 27 and the second encoder 30. Based on the current position information, the speed pattern generation unit 62 transmits a target speed signal to the first error amplification unit 65A and the second error amplification unit 65B so that an appropriate left-right speed difference is generated.

  When entering the curved portion 8, the speed pattern generating unit 62 decelerates the inner wheel and accelerates the outer wheel, thereby causing the center speed of the transport vehicle 3 to travel according to a specified speed (for example, 60 m / min). The speed pattern generation unit 62 uses a speed ratio table calculated in advance, improves calculation efficiency, and reduces processing load.

  With reference to FIG. 6, the speed ratio table at the time of traveling on a curve used by the speed pattern generation unit 62 will be described.

  As is clear from the figure, when the speed ratio between the inner ring and the outer ring is 100% when entering the curve, the speed ratio of the inner ring decreases as the speed ratio of the outer ring increases. When the outer wheel speed ratio is 115% and the inner wheel speed ratio is 85%, the state continues in a predetermined travel section. Finally, the speed ratio of the outer ring becomes smaller, the speed ratio of the inner ring becomes larger along with that, and finally both become 100%.

  In summary, in the speed ratio table, a first section 71 in which the speed ratio is separated, a second section 72 in which the speed ratio is constant, and a third section 73 in which the speed ratio is approaching are set. Yes.

  In the first section 71 and the third section 73, the first motor control unit 63 performs PID control, and the second motor control unit 64 also performs PID control. This is because a large torque is required during acceleration of the traveling wheels, and the torque balance between the left and right traveling wheels is likely to be disturbed. In order to solve this problem, it is preferable that the left and right traveling wheels are PID-controlled.

In the second section 72, the first motor control unit 63 performs PID control, while the second motor control unit 64 performs PI control. As described above, when the left and right traveling wheels travel at a constant speed in the curved portion, the second motor 29 is feedback-controlled without the differential element, although the first motor 26 is PID-controlled. Therefore, the response performance with respect to the disturbance in the second motor 29 and the second drive wheel 28 is lowered. Thereby, even if the response performance with respect to the disturbance remains high on the first motor 26 and the first drive wheel 25 side, the second drive wheel 28 follows it, and the traveling of the entire transport vehicle 3 is hardly adversely affected. In this way, the traveling behavior of the transport vehicle 3 at the time of traveling on the curved portion is stabilized.
Note that the combination of PID control and PI control may be switched between the inner and outer rings.

(9) Features The transport vehicle 3 includes a transport vehicle main body 15, left and right first drive wheels 25 and second drive wheels 28, a first motor 26 and a second motor 29, a first motor control unit 63, 2 motor control unit 64. The first drive wheel 25 and the second drive wheel 28 are provided on the transport vehicle body 15. The first motor 26 and the second motor 29 are connected to the first drive wheel 25 and the second drive wheel 28, respectively. The first motor control unit 63 performs PID control of the first motor 26. The second motor control unit 64 can switch between PID control and feedback control that does not include a differential element in order to control the second motor 29.
In the transport vehicle 3, when the first motor 26 is PID-controlled, the second motor control unit 64 can perform feedback control of the second motor 29 without including a differential element. At this time, the response performance to disturbance in the second motor 29 and the second drive wheel 28 is lowered. Thereby, even if the response performance with respect to the disturbance remains high on the first drive wheel 25 side, the second drive wheel 28 follows it, and the traveling of the entire transport vehicle 3 is hardly adversely affected. In this way, the traveling behavior of the transport vehicle 3 is stabilized.

The transport vehicle 3 travels along the travel surface, the first guide rail 6a and the second guide rail 6b, and includes a transport vehicle body 15, a pair of drive travel units 18 and a driven travel unit 19, The motor 26 and the second motor 29, a first motor control unit 63, and a second motor control unit 64 are provided. The drive travel unit 18 includes left and right first drive wheels 25 and second drive wheels 28 mounted on the travel surface, and first fixed guide rollers 31 and second supports supported by the first guide rail 6a and the second guide rail 6b. And a fixed guide roller 32. The first motor 26 and the second motor 29 are respectively connected to the first drive wheel 25 and the second drive wheel 28 provided in the drive travel unit 18. The first motor control unit 63 performs PID control of the first motor 26. The second motor control unit 64 can switch between PID control and feedback control that does not include a differential element in order to control the second motor 29.
In the transport vehicle 3, when the first motor 26 is PID-controlled, the second motor control unit 64 can perform feedback control of the second motor 29 without including a differential element. At this time, the response performance to disturbance in the second motor 29 and the second drive wheel 28 is lowered. Thereby, even if the response performance with respect to the disturbance remains high on the first motor 26 and the first drive wheel 25 side, the second drive wheel 28 follows it, and the traveling of the entire transport vehicle 3 is hardly adversely affected. In this way, the traveling behavior of the transport vehicle 3 is stabilized.
Furthermore, since the transport vehicle 3 is supported by the first guide rail 6a and the second guide rail 6b, unstable operations caused by disturbance on the second motor 29 and second drive wheel 28 side can be reduced.

The second motor control unit 64 performs PID control when the traveling speed of the transport vehicle 3 is equal to or higher than a predetermined speed, and performs feedback control that does not include a differential element when the traveling speed is lower than the predetermined speed.
In this transport vehicle 3, for example, during the positioning operation after the deceleration control, the first motor control unit 63 can execute PID control, and the second motor control unit 64 can execute feedback control that does not include a differential element. As a result, both the first motor 26 and the second motor 29 are subjected to PID control during the normal traveling of the transport vehicle 3 to improve the response performance to the disturbance in the entire transport vehicle 3, and the travel of the transport vehicle 3 during the low speed travel. The behavior can be stabilized.

When the carriage 3 travels in a curve, the second motor control unit 64 performs PID control in a region where the inner and outer wheel speed difference changes, and performs feedback control that does not include a differential element in a region where the inner and outer wheel speed difference is constant. To do.
In the transport vehicle 3, in a region where the difference between the inner and outer wheel speeds is constant during curve travel, the first motor control unit 63 can perform PID control and the second motor control unit 64 can perform feedback control that does not include a differential element. As a result, the first motor 26 and the second motor 29 are subjected to PID control during normal travel of the transport vehicle 3 to improve the response performance to the disturbance of the transport vehicle 3 as a whole. The running behavior of can be stabilized.

(10) Other Embodiments Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention.

  The second motor control unit may perform P control or other feedback control instead of PI control.

The motor controlled by the second motor control unit may be either left or right.
The first motor control unit may be able to switch between PID control and other feedback control.
In the embodiment described above, the transport vehicle travels on a track suspended from the ceiling, but the present invention is not limited to this. The track may be provided on the ground, or the transport vehicle may be suspended from the track.
In addition, as feedback control including a differential element, PD control is also possible instead of PID control.

  In the embodiment, the encoder measures the rotation of the motor, but the present invention is not limited to this. The encoder may measure the rotation of the driving wheel or the driven wheel.

The types of detection target and sensor combinations and the detection purposes are not limited to the above-described embodiment.
The installation position and number of the detection target parts are not limited to the above embodiment.

  The present invention can be widely applied to a transport vehicle in which motors are separately provided on the left and right wheels and the wheels can be driven independently.

DESCRIPTION OF SYMBOLS 1 Transfer vehicle system 2 Track 3 Transfer vehicle 4 Travel rail 4a 1st travel rail 4b Travel rail 6 Guide rail 6a 1st guide rail 6b 2nd guide rail 7 Straight line part 7a 2nd part 8 Curved part 9 Branch part 9a Branch point 11 Reflective tape 13 Bar code 14 Magnetic mark 15 Conveyor body 18 Drive travel unit 19 Drive travel unit 21 First drive wheel unit 22 Second drive wheel unit 25 First drive wheel (first travel wheel)
26 1st motor 27 1st encoder 28 2nd driving wheel (2nd traveling wheel)
29 2nd motor 30 2nd encoder 31 1st fixed guide roller 32 2nd fixed guide roller 33 1st branch guide roller 34 2nd branch guide roller 35 1st branch guide roller drive part 36 1st driven wheel 37 2nd driven wheel 40 Third fixed guide roller 41 Fourth fixed guide roller 42 Third branch guide roller 43 Fourth branch guide roller 44 Second branch guide roller drive unit 47 Photoelectric sensor 49 Linear scale 50 Bar code reader 52 Controller 54 Controller body 55 First Memory 59 Travel control unit 60 Branch control unit 61 Route map 62 Speed pattern generation unit 63 First motor control unit (first control unit)
64 Second motor control unit (second control unit)
65A 1st error amplification part 65B 2nd error amplification part 66A 1st PID control part 66B 2nd PID control part 67A 1st amplifier 67B 2nd amplifier 68 PI control part 80 Stop position

Claims (4)

The car body,
Left and right first traveling wheels and second traveling wheels provided on the vehicle body;
A first motor and a second motor respectively connected to the first traveling wheel and the second traveling wheel;
A first control unit that performs PID control of the first motor;
A second control unit capable of switching between PID control and feedback control not including a differential element to control the second motor;
A transport vehicle equipped with. A transport vehicle that travels along a travel surface and a guide rail,
The car body,
A pair of bogies provided on the front and rear of the vehicle body and having left and right first traveling wheels and second traveling wheels mounted on the traveling surface; and guide rollers supported by the guide rails;
A first motor and a second motor respectively connected to a first traveling wheel and a second traveling wheel provided on at least one of the pair of bogies;
A first control unit that performs PID control of the first motor;
A second control unit capable of switching between PID control and feedback control not including a differential element to control the second motor;
A transport vehicle equipped with.   3. The transport vehicle according to claim 1, wherein the second control unit performs PID control when the travel speed of the transport vehicle is equal to or higher than a predetermined speed, and performs feedback control that does not include a differential element when the travel speed is lower than the predetermined speed.   The second control unit performs PID control in a region where the inner / outer wheel speed difference changes when the carriage travels in a curve, and executes feedback control that does not include a differential element in a region where the inner / outer wheel speed difference is constant. The conveyance vehicle in any one of Claims 1-3.

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