JP5252003B2 - Transport vehicle system - Google Patents

Description

  The present invention relates to a transport vehicle system, and more particularly, to a transport vehicle system using a transport vehicle capable of independently driving left and right wheels.

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 the clean room of the factory and transports articles between the processing apparatuses. 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.
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 for being guided by the left and right guide rails.
Also known is a carrier system that performs two-wheel differential speed control in which separate motors are connected to the left and right wheels so that an appropriate speed difference is generated between the left and right wheels when the carriage travels a curve. (For example, see Patent Document 1).

JP 2008-52323 A

In the conventional transport vehicle, in the left and right two-wheel drive transport vehicle structure, in order to set different speeds for the outer wheel and the inner wheel during curve travel, independent speed commands are given to the respective motors. Each speed command is generated by multiplying the center speed by a left-right speed difference conversion table (speed ratio between the inner wheel and the outer wheel with respect to the center speed).
Each motor has an allowable acceleration in terms of mechanical characteristics. However, if the speed command is generated so as to generate acceleration during straight line travel (for example, maximum acceleration) when accelerating during curve section travel, the acceleration / deceleration of the motor on the outer ring side exceeds the upper limit value. That is, the motor on the outer ring side is overloaded, and in some cases, the allowable load of the servo amplifier may be exceeded and the motor may be in an abnormal state.

  An object of the present invention is to prevent an overload of a motor during traveling of a curved portion in a transport vehicle capable of independently driving left and right wheels.

  Hereinafter, a plurality of modes will be described as means for solving the problems. These aspects can be arbitrarily combined as necessary.

A transport vehicle system according to an aspect of the present invention includes a transport vehicle that travels on a predetermined route and a control unit that controls travel of the transport vehicle. The transport vehicle includes a vehicle body, two traveling wheels provided on the left and right sides of the vehicle body, and two motors respectively connected to the two traveling wheels. The control unit includes a speed command generation unit and a detection unit. The speed command generator is arranged between the inner and outer wheel speed ratio constant sections in the middle of the curve section and the both ends of the curve section so that a difference in speed occurs between the inner and outer wheels with respect to the reference speed when the carriage travels on the curve section. A speed command is generated and given to two motors in a certain inner / outer ring speed ratio changing section. The detection unit can detect that the transport vehicle is traveling along the curved portion. When the detection unit detects that the transport vehicle enters the curved portion during acceleration, the speed command generation unit accelerates the acceleration when entering the motor corresponding to the traveling wheel serving as the outer wheel in the inner / outer wheel speed ratio change section. Generate and give a speed command that gives the following acceleration, and generate a speed command that gives a speed that is less than the speed difference from the speed of the running wheel that is the outer ring for the motor that corresponds to the running wheel that is the inner ring. And give. That is, the speed command given to the motor corresponding to the traveling wheel serving as the inner ring is a value such that the speed of the traveling wheel serving as the inner ring becomes a speed obtained by reducing the speed difference by more than the speed of the traveling wheel serving as the outer ring.
In this transport vehicle system, when the transport vehicle enters the curved portion while accelerating, a high load is not applied to the motor serving as the outer ring.

If the controller detects an approach to the curve during acceleration, the controller will reach the maximum speed within the inner / outer wheel speed ratio change interval if the motor corresponding to the outer running wheel maintains the current acceleration. You may further have the judgment part which judges whether or not. If the determination unit determines that the maximum speed is not reached, the speed command generation unit generates and gives a speed command for maintaining the current acceleration to the motor corresponding to the traveling wheel serving as the outer wheel.
In this transport vehicle system, the calculation load is not increased in the speed command generator.

If it is determined that the maximum speed is reached in the above case, the speed command generation unit generates a speed command such that the traveling wheel that becomes the outer wheel reaches the maximum speed after the end point of the inner / outer wheel speed ratio change section, You may give a speed command with respect to the motor corresponding to the driving | running | working wheel used as an outer ring | wheel.
In this transport vehicle system, if the motor corresponding to the traveling wheel that is the outer ring maintains the current acceleration, the outer ring is prevented from exceeding the maximum speed even if the maximum speed is reached within the inner / outer wheel speed ratio change section. The

If the detection unit detects that the transport vehicle exits from the curved portion during deceleration, the speed command generation unit reduces the motor speed corresponding to the traveling wheel serving as the outer wheel when the vehicle exits. A speed command that generates and gives a speed command that results in a deceleration that is less than or equal to the speed is such that the speed corresponding to the inner wheel is less than the speed difference of the outer wheel. May be generated and given. That is, the speed command given to the motor corresponding to the traveling wheel serving as the inner ring is a value such that the speed of the traveling wheel serving as the inner ring becomes a speed obtained by reducing the speed difference by more than the speed of the traveling wheel serving as the outer ring.
In this conveyance vehicle system, when the conveyance vehicle decelerates from the curved portion while decelerating, a high load is not applied to the motor corresponding to the traveling wheel serving as the outer ring.

When the detection unit detects that the transport vehicle enters the curved portion during deceleration, the speed command generation unit reduces the speed at the time of entry to the motor corresponding to the traveling wheel that is the inner wheel in the inner / outer wheel speed ratio change section. A speed command that generates and gives a speed command that results in a deceleration that is less than or equal to the speed, and that is a speed that is greater than the speed difference of the running wheel that is the inner ring with respect to the motor that corresponds to the running wheel that is the outer ring. May be generated and given. That is, the speed command given to the motor corresponding to the traveling wheel serving as the outer wheel is a value such that the speed of the traveling wheel serving as the outer wheel becomes a speed obtained by increasing the speed difference by more than the speed of the traveling wheel serving as the inner wheel.
In this conveyance vehicle system, when the conveyance vehicle decelerates from the curved portion while decelerating, a high load is not applied to the motor corresponding to the traveling wheel serving as the inner ring.

If the detection unit detects that the transport vehicle exits from the curved portion during acceleration, the speed command generation unit determines the acceleration at the time of exit for the motor corresponding to the traveling wheel serving as the inner wheel in the inner / outer wheel speed ratio change section. Generates and gives a speed command that gives the following acceleration, and generates a speed command that gives a speed that is greater than the speed difference of the running wheel that is the inner ring with respect to the motor that corresponds to the running wheel that is the outer ring. May be given. That is, the speed command given to the motor corresponding to the traveling wheel serving as the outer wheel is a value such that the speed of the traveling wheel serving as the outer wheel becomes a speed obtained by increasing the speed difference by more than the speed of the traveling wheel serving as the inner wheel.
In this transport vehicle system, when the transport vehicle exits from the curved portion while accelerating, a high load is not applied to the motor corresponding to the traveling wheel serving as the inner ring.

The conveyance vehicle system may further include guide rails provided along the route. In that case, the transport vehicle further includes a front guide roller pair and a rear guide roller pair provided on the front side and the rear side of the traveling wheels, respectively. The control unit holds travel locus information in which the front guide roller pair and the rear guide roller pair do not contact the guide rail when the transport vehicle travels on the curved portion. The speed command generation unit creates a speed command conversion table for generating a speed command based on the travel locus information.
When the transport vehicle travels on the curved portion, the front guide roller pair and the rear guide roller pair are in the guide position close to the guide rail. On the other hand, the control unit creates a speed command using a speed command conversion table created based on ideal travel locus information when the transport vehicle travels on a curved part. Therefore, the front guide roller pair and the rear guide roller pair are unlikely to contact the guide rail at the curved portion. Conventionally, the control is based on the assumption that the front guide roller pair and the rear guide roller pair of the transport vehicle are in contact with the guide rails at the entrance and exit of the curved portion. It was big. In contrast, in this transport vehicle system, control is actively performed so that the front guide roller pair and the rear guide roller pair of the transport vehicle are not in contact with the guide rails even at the guide positions at the entrance and exit of the curved portion. doing. Therefore, it is difficult for the guide roller to contact the guide rail.

  In the transport vehicle system according to the present invention, in the transport vehicle capable of independently driving the left and right wheels, overloading of the motor is prevented during traveling of the curved portion.

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 top view which shows the ideal driving | running | working locus | trajectory obtained by calculation. The elements on larger scale of FIG. The figure which shows the dimensional relationship of a traveling wheel. The figure which showed typically the positional relationship of the guide rail and guide roller in a curved part. Speed ratio table when running a curve section. The flowchart which shows operation | movement of the traveling control part at the time of curve part traveling. The graph which showed the relationship of the time-speed of each wheel when approaching a curve, accelerating, and the speed ratio table at the time of curve driving | running | working. When entering a curve while accelerating, when a speed command is generated so that the outer wheel does not reach the maximum speed within the two-wheel speed ratio change section, the time-speed relationship of each wheel and the speed during curve driving Graph showing a ratio table. When entering a curve while accelerating, when a speed command is generated so that the center of the turning axis does not reach the reference speed within the two-wheel speed ratio change section, the time-speed relationship of each wheel and the curve Speed ratio table and graph The graph which showed the relationship of the time-speed of each wheel at the time of starting from the inside of a curve, and the speed ratio table at the time of curve driving. The graph which showed the relationship of the time-speed of each wheel at the time of leaving from a curve, decelerating, and the speed ratio table at the time of curve driving | running | working.

(1) Carrier Vehicle System A carrier vehicle system 1 in which an embodiment of the present invention is adopted will be described with reference to 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.

  The layout of the transport vehicle system 1 will be described with reference to FIG. FIG. 2 is a partial plan view of the transport vehicle system. As shown in FIG. 2, the trajectory 2 includes a first straight portion 201, a branch portion 206 at the tip of the first straight portion 201, a curve or curved portion 203 that turns to the right from the branch portion 206, and a branch portion 206. It has the 2nd linear part 202 extended straightly as it is. Hereinafter, the curved portion 203 is used as an example of the curved portion in the description of the traveling of the curved portion of the transport vehicle 3.

  The first traveling rail 4 a and the second traveling rail 4 b extend from the first straight portion 201 through the branching portion 206 into both the second straight portion 202 and the curved portion 203.

  The first guide rail 6 a is not provided at the branching portion 206 in the portion of the first traveling rail 4 a from the first straight portion 201 toward the second straight portion 202. Furthermore, the second guide rail 6 b is not provided at the branching portion 206 in the portion of the second traveling rail 4 b from the first straight portion 201 toward the curved portion 203.

(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. In FIG. 1, the pivot axis center 38 of the drive travel unit 18 is shown.

  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 (31, 32), and a branch guide roller mechanism (33, 34, 35).

  The first drive wheel unit 21 is attached to the right end portion of the main body frame 20 and has a first traveling wheel 25, a first motor 26, and a first encoder 27. The first traveling wheel 25 is placed on the traveling surface of the first traveling rail 4a. The first motor 26 is connected to the first traveling 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 are obtained.

  The second drive wheel unit 22 is attached to the left end portion of the main body frame 20, and includes a second traveling wheel 28, a second motor 29, and a second encoder 30. The second traveling wheel 28 is placed on the traveling surface of the second traveling rail 4b. The second motor 29 is connected to the second traveling 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 are obtained.

  The fixed guide roller mechanism (31, 32) 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 traveling wheel 25 in the traveling direction, and is always close to the inside 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 traveling wheel 28 in the traveling direction, and is always close to the inside of the second guide rail 6b.

The branch guide roller mechanism (33, 34, 35) is a mechanism for performing a branch operation in the branch portion 206, and includes a pair of first branch guide rollers 33, a second branch guide roller 34, and a first branch guide roller. And a drive unit 35 (FIG. 3).
The first branch guide roller 33 is arranged corresponding to the first fixed guide roller 31, and constitutes a front guide roller pair 81 and a rear guide roller pair 83 by both. The second branch guide roller 34 is arranged corresponding to the second fixed guide roller 32, and constitutes a front guide roller pair 85 and a rear guide roller pair 87 by both. 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 moved between the guide position and the non-guide position by the first branch guide roller driving unit 35 (FIG. 3). At the guide position, the first branch guide roller 33 and the second branch guide roller 34 are close to the outside of the first guide rail 6a. In the non-guide position, the first branch guide roller 33 and the second branch guide roller 34 are separated upward from the first guide rail 6a.

The driven traveling unit 19 mainly includes a main body frame 23, a first driven wheel 36, a second driven wheel 37, a second fixed guide roller mechanism (40, 41), and a second branch guide roller mechanism (42, 43, 44).
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 (40, 41) 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 of the first driven wheel 36 in the traveling direction, and is always close to the inside 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 close to the inside of the second guide rail 6b.

  The second branch guide roller mechanism (42, 43, 44) is a mechanism for performing a branch operation in the branch portion 206, and includes a pair of third branch guide rollers 42, a fourth branch guide roller 43, and a second branch. And a guide roller driving unit 44 (FIG. 3).

  The third branch guide roller 42 is disposed corresponding to the third fixed guide roller 40. The fourth branch guide roller 43 is disposed corresponding to the fourth fixed guide roller 41. The second branch guide roller driving unit 44 (FIG. 3) is a mechanism for changing the positions of the third branch guide roller 42 and the fourth branch guide roller 43.

  With the above structure, the third branch guide roller 42 and the fourth branch guide roller 43 are moved between the guide position and the non-guide position by the second branch guide roller driving unit 44 (FIG. 3). At the guide position, the third branch guide roller 42 and the fourth branch guide roller 43 are close to the outside of the first guide rail 6a. In the non-guide position, the third branch guide roller 42 and the fourth branch guide roller 43 are separated upward from the first guide rail 6a.

  When the transport vehicle 3 travels on the curved portion 203 in FIG. 2, the first branch guide roller 33 and the third branch guide roller 42 are disposed at the guide position. On the other hand, at that time, the second branch guide roller 34 and the fourth branch guide roller 43 are arranged at the non-guide position. In addition, when the conveyance vehicle 3 travels the first linear portion 201, each branch guide roller may be disposed at either the non-guide position or the guide position.

(3) Detected part and sensor 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 bar code 13, and the magnetic mark 14 are illustrated inside the traveling rail 4, but are actually provided on the traveling rail 4 or the upper surface of the guide rail 6. .
The reflective tape 11 is a member for detecting the position of the transport vehicle 3 in the curved portion 203 and is disposed in the curved portion 203. In this embodiment, the start end 11a of the reflective tape 11 is disposed before the actual start position 203a of the curved portion 203 in the traveling direction. Further, the end (not shown) of the reflective tape 11 is arranged in front of the actual end of the curved portion (not shown).
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 non-magnetic material such as copper or aluminum. In this embodiment, the magnetic mark 14 is disposed on the first straight portion 201, and the stop position 80 is in the middle of the magnetic mark 14.

  As shown in FIG. 3, the driving traveling unit 18 and the driven traveling unit 19 are further provided with a photoelectric sensor 47, a linear scale 49, and a barcode reader 50. The photoelectric sensor 47 is for detecting the reflective tape 11. Note that the photoelectric sensor 47 in the figure is a sensor for detecting a position during traveling on a curved portion that is bent to the right, and a sensor (not shown) for the curved portion that is bent to the left is provided separately. 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 can communicate with the transport vehicle 3. The transport vehicle controller 52 includes a controller main body 54 and a 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. A route map is stored in the memory 55. 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 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 traveling 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, a second motor control unit 64, and a compensation speed ratio table 90. The route map 61 and the compensation speed ratio table 90 are stored in a memory in the travel control unit 59. The speed pattern generation unit 62 can communicate with the transport vehicle controller 52.
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.

  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 pattern of travel speed to the stop position.

  The first motor control unit 63 mainly includes a first error amplification unit 65A, a first feedback control unit 66A, and a first amplifier 67A. The first error amplifier 65A amplifies the error. The first feedback control unit 66A performs, for example, PID control or PI control based on the error obtained by the first error amplification unit 65A. PID control and PI control can be switched. The first amplifier 67A transmits a current-amplified speed command to the first motor 26. The first encoder 27 detects the rotation speed of the rotation shaft of the first motor 26, and the current position and speed of the first traveling wheel 25 obtained thereby are input to the speed pattern generation unit 62 or the first error amplification unit 65A. Is done. The configuration of the first motor control unit 63 is an example.

  The second motor control unit 64 mainly includes a second error amplification unit 65B, a second feedback control unit 66B, and a second amplifier 67B. The second error amplifying unit 65B amplifies the error. The second feedback control unit 66B performs PID control or PI control based on the error obtained by the second error amplification unit 65B. PID control and PI control can be switched. The second amplifier 67B transmits the current-amplified speed command to the second motor 29. The second encoder 30 detects the rotational speed of the rotating shaft of the second motor 29, and the current position and speed of the second traveling wheel 28 obtained thereby are input to the speed pattern generator 62 or the second error amplifier 65B. Is done. In addition, the structure of the 2nd motor control part 64 is one Example, Comprising: This invention is not limited to this.

(6) General Explanation of Travel Control Operation Generally, the transport vehicle 3 has a required travel distance obtained from the route map 61 along the track 2, a current position obtained from the first encoder 27 and the second encoder 30, and Travel control is performed according to the current speed.

  A control operation when the transport vehicle 3 travels along the curved portion 203 will be described. When traveling on the curved section 203, 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 generator 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. The speed pattern generation unit 62 uses the current position information and the compensation speed ratio table 90 (described later) to generate separate target speed signals so that an appropriate left-right speed difference is generated, and outputs them to the first motor control unit. 63 and the second motor control unit 64.

  When the speed pattern generating unit 62 enters the curve unit 203 at a constant speed, the inner wheel is decelerated and the outer wheel is accelerated, 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 the compensation speed ratio table 90 calculated in advance to improve calculation efficiency and reduce the processing load.

  As described above, when the transport vehicle 3 travels the curved portion 203, the behavior is stable even though the left and right motors cannot be perfectly synchronized.

(7) Curved part traveling locus The speed pattern generator 62 has an ideal curved part traveling locus table 98 in advance. The curved portion traveling locus is a locus on which the guide roller can accurately trace the shape of the guide rail. That is, in this locus, the guide roller does not contact the guide rail.

  The method for obtaining the curve portion traveling locus will be described with reference to FIGS. FIG. 5 is a plan view showing an ideal travel locus obtained by calculation. FIG. 6 is a partially enlarged view of FIG. FIG. 7 is a diagram showing the dimensional relationship of the traveling wheels. FIG. 8 is a diagram schematically showing the positional relationship between the guide rail and the guide roller in the curved portion.

An ideal curved portion traveling locus is obtained as follows. First, a reference entrance trajectory is determined. Specifically, the rear position x _a of the guide roller pair, from the start position 203a to a position spaced above the pitch L of the front guide rollers 81 and the rear guide rollers 83, the pivot axis at a predetermined distance [Delta] x _a resolution The coordinates of the center track P ₀ , the inner ring track P ₁ , and the outer ring track P ₂ are obtained. For example, the distance of the interval for changing the _{x a} is 500mm from the starting position 203a, the pitch L of the guide rollers is 480 mm, [Delta] x _a is 0.05 _mm, P 0, _{P 1} and _{P 2} 1000 places can be obtained.

The specific calculation formula is as follows.
First, the turning angle alpha ₂ is calculated. Incidentally, R is the radius of the first guide rail 6a, L is the longitudinal pitch of the guide roller pairs, x _a is the x-coordinate of the rear guide rollers, x _R in X-coordinate of the start position 203a is there.
l = √ ((x _R −x _a ) ² + R ² )
R ² = l ² + L ² −2lL cos α ₁
α ₁ = cos ⁻¹ ((R ² −l ² −L ² ) / (− ² lL))
α ₀ = tan ⁻¹ R / (x _R −x _a )
α ₂ = α ₀ −α ₁

Next, the coordinates of P ₀ , P ₁ and P ₂ are calculated from the turning angle α ₂ .
θ ₀ = θ ₀₀ −α ₂
θ ₁ = θ ₁₀ -α ₂
θ ₂ = θ ₂₀ −α ₂
Thus, the coordinates of P ₀ , P ₁ and P ₂ are as follows.
P ₀ (x ₀ , y ₀ ) = (x _a + l ₀ cos θ ₀ , l ₀ sin θ ₀ )
P ₁ (x ₁ , y ₁ ) = (x _a + l ₁ cos θ ₁ , l ₁ sin θ ₁ )
P ₂ (x ₂ , y ₂ ) = (x _a + l ₂ cos θ ₂ , l ₂ sin θ ₂ )
By integrating the intervals of P ₀ , P ₁ , and P ₂ , the moving distances of the first traveling wheel 25, the second traveling wheel 28, and the turning shaft center 38 are obtained.
The positional relationship between the guide rail and the guide roller at the curved portion entrance will be described with reference to FIG. An intermediate point between the front guide roller pair 81 is a first intermediate point 95, and an intermediate point between the rear guide roller pair 83 is a second intermediate point 97. In FIG. 8, a front guide roller pair 81 and a rear guide roller pair 83 are denoted by reference symbol A in the first linear portion 201, and a state where the front guide roller pair 81 has reached the start position 203a is denoted by reference symbol B. A state in which the rear guide roller pair 83 is in a position where it reaches the start position 203a is indicated by a symbol C, and is indicated by a symbol D in the curved portion 203. At any position, the first intermediate point 95 and the second intermediate point 97 coincide with the intermediate in the width direction of the first guide rail 6a. In this way, the guide rollers on both sides of the first guide rail 6a are arranged so as to always leave the maximum gap.
The reference exit trajectory is extracted from the calculation result of the reference entrance trajectory. Specifically, a point where the rear guide roller pair 83 enters the curved portion 203 is searched as a change end point, and rearranged in the reverse direction. Further, by integrating the intervals of P ₁ and P ₂ , the moving distances of the first traveling wheel 25, the second traveling wheel 28, and the turning shaft center 38 are obtained.
The reference entrance trajectory and the reference exit trajectory obtained as described above are stored in the curve portion travel trajectory table 98 in the speed pattern generator 62.

(8) Speed Ratio Table A reference speed ratio table (wheel speed conversion table) 70 at the time of curve traveling that the speed pattern generation unit 62 uses as a reference speed command will be described with reference to FIG. The reference speed ratio table 70 is a table that determines the reference speed ratio of the left and right drive wheels with respect to the curve travel time. The first speed ratio change section 101 at the curve entrance and the second speed ratio change section 102 at the curve exit. And a constant speed ratio section 103 in the middle of the curve.

At the curve start point, the speed ratio between the inner ring and the outer ring is 100%. In the first speed ratio change section 101, the reference inner ring speed ratio 73 decreases as the reference outer ring speed ratio 71 increases. When the reference outer ring speed ratio 71 becomes 100 + α% (for example, a total of 115%) and the reference inner ring speed ratio 73 becomes 100−α% (for example, a total of 85%), this state continues in the constant speed ratio section 103. . Finally, in the second speed ratio change section 102, the reference outer ring speed ratio 71 decreases, the reference inner ring speed ratio 73 increases accordingly, and finally both become 100%.
The value of α is set to be different according to the distance between the left and right drive wheels and the curve curvature.

Next, a method for creating the reference speed ratio table 70 will be described. The speed pattern generator 62 sets the P ₁ and P ₂ positions on the time axis so that the moving speed at the turning axis center P ₀ becomes a set constant value (for example, 60 m / min) from the output of the reference trajectory. Extract by criteria. Specifically, separated by P ₀ position, generates a speed pattern to the outlet from the curve section inlet. Δt is the resolution of the time axis is required to be sufficiently larger than [Delta] x _a, for example, 1 millisecond. The boundary condition division and velocity pattern creation method by the P ₀ position is as follows.
- straight portions constant speed movement ... P ₀ and translation-inlet (two-wheel differential velocity difference starting position 1-2 wheel differential velocity difference ending position 1) extracted from ... reference inlet locus curves Chujo uniform motion .. Curve Speed reference (simple calculation from curve radius)
And outlet (two-wheel differential velocity difference starting position 2-2 wheel differential velocity difference end position 2) parallel ... From the reference outlet path and the extraction-linear portion constant speed movement ... P ₀ moves

  When the transport vehicle 3 travels on the curved portion 203 in FIG. 2, the first feedback control unit 66 </ b> A of the first motor control unit 63 controls the first motor 26 on the inner ring side, that is, the side holding the guide rail. PID control is continuously performed. In contrast, on the outer ring side, that is, the side not holding the guide rail, the second feedback control unit 66B of the second motor control unit 64 is switched from PID control to PI control. In other words, during traveling on the curved portion, the first motor 26 is PID-controlled and the second motor 29 is PI-controlled. The reason why the inner wheel PID-outer wheel PI control is left in this way despite the formation of the speed command so as to travel on the ideal locus is that the guide roller may come into contact with the guide rail due to the rail shape error and the installation error. This is to reduce the load at the time of contact.

  Next, servo following compensation for the reference speed command will be described. Servo tracking compensation is performed to compensate for the difference between the left and right wheels caused by inner wheel PID-outer wheel PI control by adding feedforward control to the reference speed command. The parameters for servo tracking compensation employed in this embodiment are response and deviation. The response is a delay time at the start of behavior change and a delay time at the end of behavior change. The deviation is a percentage with respect to the desired speed at the time when the curve portion constant speed is reached.

With reference to FIG. 9, a compensation speed ratio table 90 at the time of curve travel that is used as a speed degree command for which the speed pattern generation unit 62 has performed servo tracking compensation will be described. The compensation speed ratio table 90 has a compensation outer ring speed ratio 91 and a compensation inner ring speed ratio 93. The compensated outer ring speed ratio 91 is earlier than the reference outer ring speed ratio 71 at the start of behavior change and at the end of behavior change. The compensated inner ring speed ratio 93 is also faster at the start of behavior change and at the end of behavior change than the reference inner ring speed ratio 73. Compared to the compensated inner ring speed ratio 93, the compensated outer ring speed ratio 91 is earlier when the behavior change starts and when the behavior change ends.
Further, the compensated outer ring speed ratio 91 has a constant speed larger than the reference outer ring speed ratio 71.

The compensation speed ratio table 90 is created as follows. First, the time delay and the speed deviation are obtained by a separate experiment. The speed pattern generator 62 creates a reference entrance locus and a reference exit locus in the time domain, and further extracts a boundary time from the reference speed command. Furthermore, the speed pattern generation unit 62 creates a compensation table by simply performing linear interpolation in the time domain, for example.
The speed pattern generation unit 62 generates a speed pattern from the entrance to the exit of the curve section by dividing it by the boundary time from the compensation table.
The boundary condition division by time and the speed pattern creation method are as follows.
- straight portions constant speed movement ... P ₀ and translation-inlet (two-wheel differential velocity difference starting time 1-2 wheel differential velocity difference end time 1) ... compensation inlet trajectory extraction curves Chujo uniform motion .. curve from Speed reference (simple calculation from curve radius)
And outlet parallel to the (two-wheel differential velocity difference starting time 2-2 wheel differential velocity difference end time 2) ... extracted from the compensation outlet path traveled straight portion constant speed movement ... P ₀ moves

(9) Detailed Description of Curved Section Travel Control Hereinafter, the control operation of the speed pattern generation section 62 will be described with reference to FIGS. FIG. 10 is a flowchart illustrating the operation of the traveling control unit during traveling on the curved portion. FIGS. 11 to 12 are graphs showing a time-speed relationship of each wheel when entering a curve while accelerating, and a speed ratio table during curve traveling. In FIG. 11 to FIG. 13, the inner ring speed, the outer ring speed, and the turning shaft center speed are shown using solid lines, and the compensation speed ratio table 90 is shown using two-dot chain lines. In these drawings, the compensation speed ratio table 90 is drawn so that the speed ratio matches the speed.
In the figure, V ₁ represents the maximum value of the inner ring speed assumed in the constant speed ratio section 103, V ₂ represents the maximum value of the outer ring speed assumed in the constant speed ratio section 103, and V _c represents The maximum value of the pivot axis center speed assumed in the constant speed ratio section 103 is shown.
In the following description, as shown in FIGS. 11 to 13, the operation when the transport vehicle 3 starts from the first straight portion 201 and enters the curved portion 203 with a constant acceleration a ₀₁ will be described. The acceleration a _{01 at} this time may be an allowable maximum value or its vicinity.
Note that the speed pattern generation unit 62 continues to give a speed command to the first motor 26 and the second motor 29 even before entering the curve unit 203.

  In step S <b> 1, the speed pattern generation unit 62 waits for reaching the start position 203 a of the curve unit 203. The fact that the start position 203a has been reached is grasped by the photoelectric sensor 47 detecting the start end 11a of the reflective tape 11. At this time, the speed of the traveling wheel is v in FIG.

  In step S2, the speed pattern generation unit 62 determines whether or not the transport vehicle 3 is accelerating (in this case, it is assumed that the vehicle is traveling at a constant speed if it is not accelerating). If “Yes”, the process proceeds to step S3, and if “No”, the process proceeds to normal curve traveling control. In normal curve traveling control, the inner wheel speed and the outer wheel speed are determined by multiplying the center speed of the turning axis by the compensation speed ratio table 90.

In step S3, the speed pattern generating section 62 calculates the outer ring when continued current acceleration a ₀₁ the time t ₁₁ to travel the first speed ratio change section 101. The acceleration for calculating the t ₁₁ in this embodiment, may be the same as a _01, it may be less than it.
In addition, the speed pattern generation unit 62 calculates the inner ring speed by multiplying the reference speed by the compensation speed ratio table 90. Therefore, the inner ring speed is a speed obtained by reducing a normal speed difference (difference between the reference speed and the inner ring speed) by more than the outer ring speed.

In step S4, the speed pattern generating section 62 _obtains an acceleration _{a 11} pivot center 38 until _{t 11} elapses. Specifically, first, the speed pattern generation unit 62 calculates the turning center speed v ₁₁ at the time t ₁₁ from the outer ring speed at the time t ₁₁ and the compensation speed ratio table 90. Then, the speed pattern generating section 62, _v, based on the _{v 11} and _{t 11,} calculate the acceleration _{a 11} pivot center 38 until _{t 11.} Specifically, an equation of a ₁₁ = (v ₁₁ −v) / t ₁₁ is used. Incidentally, _{a 11} As is apparent from the figure is smaller than _{a 01.}

In step S < _b > 5, the speed pattern generation unit 62 determines whether or not the outer ring speed becomes the outer ring maximum speed V < _b > ₂ within the first speed ratio change section 101. If “No”, the process proceeds to step S6, and if “Yes”, the process proceeds to step S17.

  In step S6, the speed pattern generation unit 62 generates a reference speed command based on the turning axis center speed.

  In step S <b> 7, the speed pattern generation unit 62 converts the reference speed command into a left / right speed difference command using the compensated speed ratio table 90. Specifically, the multiplication factor of the corresponding position is obtained from the position of the carriage 3 in the curved portion 203 and the compensation speed ratio table 90, and the current reference speed is multiplied by the multiplication factor, so that the inner ring speed and the outer ring at the corresponding position are obtained. Calculate the speed. That is, an outer ring speed command is created by integrating the value of the compensated outer ring speed ratio 91 with respect to the turning axis center speed, and the inner ring speed is obtained by adding up the value of the compensated inner ring speed ratio 93 with respect to the turning axis center speed. Create directives.

  In step S <b> 8, the speed pattern generation unit 62 outputs a left / right speed difference command to the first motor control unit 63 and the second motor control unit 64, respectively.

In step S9, the speed pattern generating section 62, the pivot center speed is determined whether the host vehicle has reached the reference speed V _c before t ₁₁ elapses. If “No”, the process proceeds to step S10, and if “Yes”, the process proceeds to step S22.

In step S10, the speed pattern generating section 62 _determines whether _{t 11} has elapsed. If “No”, the process returns to step S6, and if “Yes”, the process proceeds to step S11. Thus, the pivot center speed up or t ₁₁ reaches the reference speed Vc has elapsed, step S6~8 is repeatedly executed.

In step S11, the speed pattern generating section 62, the outer ring speed of the outer ring when the continued current acceleration a ₀₁ that calculates the time t ₁₂ to reach the outer ring maximum velocity V _2. The acceleration for calculating the t ₁₂ is may be the same as a _01, it may be less than it.

In step S12, the speed pattern generating section _62, based on V _{c, v 11} and _{t 12,} obtains the acceleration _{a 12} pivot center 38 until _{t 12.} Specifically, an equation of a ₁₂ = (V _c −v ₁₁ ) / t ₁₂ is used. _{A 12} As is apparent from the _figure, smaller than _{a 01,} and greater than _{a 11.}

  In step S13, the speed pattern generator 62 generates a reference speed command based on the turning axis center speed.

In step S14, the speed pattern generating section 62 generates the speed of the outer race after t ₁₂ elapses the speed command of the left and right of the inner ring and so the outer ring maximum velocity V ₂ will change so that the inner maximum velocity V ₁ To do.

  In step S <b> 15, the speed pattern generation unit 62 outputs a left / right speed difference command to the first motor control unit 63 and the second motor control unit 64, respectively.

In step S16, the speed pattern generating section 62 _determines whether _{t 12} has elapsed. If “No”, the process returns to step S13, and if “Yes”, the process shifts to normal curve traveling control. _Thus, until _{t 12} has elapsed, step S13~S15 are repeated.

Next, with reference to FIG. 12, the speed of the outer ring in the first speed ratio changing section 101 will be described step S17~ step S21 is a control operation when the result reaches the outer maximum velocity V _2.

In step S <b> 17 of FIG. 10, the speed pattern generation unit 62 recalculates the acceleration a <b> ₁₁ in the first speed ratio change section 101 of the turning axis center 38. Specifically, the speed pattern generating section _62, based on _V 2, v and _{t 11,} obtains the acceleration _{a 11} pivot center 38 until _{t 11.} Specifically, a ₁₁ = (V ₂ −v) / t ₁₁ . As a result, the outer wheel speed becomes the outer wheel maximum speed V ₂ when t _{11 has} elapsed, that is, at the end of the first speed ratio change section 101. As is apparent from FIG. 12, the acceleration a ₀₁ ′ of the outer ring during t ₁₁ is smaller than the acceleration a ₀₁ of the outer ring when entering the curve.

  In step S18, the speed pattern generation unit 62 generates a reference speed command based on the turning axis center speed.

In step S19, the speed pattern generating section 62, the speed command of the left and right speed of the outer race after t ₁₁ elapses will change such that the speed of the inner ring and so that the outer ring maximum velocity V ₂ is the inner ring maximum velocity V ₁ Is generated.

  In step S <b> 20, the speed pattern generation unit 62 outputs a left / right speed difference command to the first motor control unit 63 and the second motor control unit 64, respectively.

In step S21, the speed pattern generating section 62 _determines whether _{t 11} has elapsed. If "No", the process returns to step S18, and if "Yes", the process shifts to normal curve traveling control. _Thus, until the _{t 11} has elapsed, step S18~ step S20 is repeatedly executed.

Next, with reference to FIG. 13, the speed of the pivot center 38 will be described step S22~ step S25 is a control operation when the result reaches the reference speed V _c at the first speed ratio change section 101.

In step S22 to step S24 in FIG. 10, the speed pattern generation unit 62 generates a reference speed command centered on the turning axis, further generates inner and outer ring speed commands, and finally transmits them to the motor. More specifically, the speed pattern generating section 62, to the speed of the turning shaft center 38 becomes the reference velocity V _c, the reference speed of the pivot center 38 as the acceleration a ₁₁ is maintained in the pivoting axis center 38 Generate commands and create inner and outer ring speed commands. Then, the speed pattern generating section 62, thereafter the speed of the turning shaft center 38 becomes the pivot center maximum speed V _c maintains the speed of the pivot center 38 constant. Further, the speed pattern generation unit 62 sets the outer ring speed so that the acceleration up to that time is maintained. Then, the speed pattern generation unit 62 sets the inner ring speed so as to be symmetric with the outer ring speed around the turning axis center speed.

At step S25, the speed pattern generating section 62, the speed of the outer race to determine whether the host vehicle has reached the outer ring maximum velocity V _2. If “No”, the process returns to step S22, and if “Yes”, the process shifts to normal curve traveling control. Thus, to the speed of the outer ring reaches the outer maximum velocity _{V 2,} steps S22~S24 are repeated.

(10) When Starting from the Middle of a Curve Speed control when the transport vehicle 3 starts from the middle of the curved portion 203 will be described with reference to FIG. FIG. 14 is a graph showing a time-speed relationship of each wheel when starting from a curve and a speed ratio table during curve traveling.

In this embodiment, the conveyance vehicle 3 starts from the first speed ratio change section 101 in the curved portion 203. In this case, the speed pattern generation unit 62 uses the outer wheel acceleration a ₀₁ as a reference, and when the outer wheel speed reaches the outer wheel maximum speed V ₂ , the turning axis center 38 reaches the reference speed V _c and the inner wheel speed becomes the inner wheel speed. to reach the maximum velocity _{V 1,} to determine the acceleration _{a 11} and the inner ring of the acceleration _{a 12} pivot center 38. Then, the speed pattern generator 62 continues to give a speed command for realizing the above-described acceleration to the inner ring and the outer ring.

(11) Speed Control at Curve Exit Using FIG. 15, speed control in the case where the transport vehicle 3 leaves the curved portion 203 while decelerating will be described. FIG. 15 is a graph showing a time-speed relationship of each wheel when leaving the curve while decelerating, and a speed ratio table during curve traveling.

When the deceleration is started, the speed pattern generation unit 62 calculates a time t ₂₁ required for the outer ring speed to become zero when the current deceleration a ₀₂ is continued. Specifically, t ₂₁ = V ₂ / a ₀₁ is used. Incidentally, the deceleration for calculating the t ₂₁ is may be the same as a _02, may be less than it.

The speed pattern generation unit 62 obtains the deceleration a ₂₁ of the turning axis center 38 in the second speed ratio change section 102. Specifically, first, the speed pattern generation unit 62 obtains a deceleration a ₂₁ such that the speed of the turning axis center 38 becomes zero after the elapse of t _21, and turns so that such a deceleration is realized. Generate axis center speed command.

Reflective tape is OFF, the speed pattern generating section 62, the _{t 22} is the time until the second speed ratio changing section 102 terminates determined, _further determining the velocity _{v 22} at _{t 22} elapses. _Moreover, determining the deceleration _{a 22} in _{t 22} from _{v 22. a 22 = (v 22 -v 11} ) is _{/ t 22.}

Speed pattern generating section 62 generates a reference speed command for the turning shaft center as the deceleration a ₂₂ is maintained. Further, the speed pattern generator 62 multiplies the reference speed command by the speed pattern generator 62 to calculate the speeds of the left and right wheels, and gives the speed command to each motor.
When the transport vehicle reaches the end point of the curved portion, the speed pattern generation unit 62 generates a speed command so that the deceleration of the turning axis center 38 becomes _a01 . At this time, the speeds of the left and right wheels coincide with the speed of the pivot axis center 38.

  In the above embodiment, even if the acceleration / deceleration is set to an allowable maximum value or a value close to the allowable maximum value when entering and exiting the curved portion, the maximum value of the acceleration / deceleration is not exceeded at the entrance and exit of the curved portion. Therefore, overload is unlikely to occur in the motor. In addition, since the acceleration / deceleration can be set to an allowable maximum value or a value close thereto when entering and exiting the curved portion, traveling efficiency does not decrease.

(12) Features The embodiment can be expressed as follows.
(A) The transport vehicle system 1 includes a transport vehicle 3 that travels on a predetermined route, and a travel control unit 59 that controls travel of the transport vehicle 3. The transport vehicle 3 includes a transport vehicle main body 15, two traveling wheels 25 and 28 provided on the left and right of the transport vehicle main body 15, and two motors 26 connected to the two traveling wheels 25 and 28, respectively. 29. The travel control unit 59 includes a speed pattern generation unit 62 and a photoelectric sensor 47. The speed pattern generator 62 has a curved portion so that when the transport vehicle 3 travels the curved portion 203, a speed difference is generated with respect to the inner and outer wheels with respect to the reference speed with respect to the two traveling wheels 25 and 28. A speed command is generated in the speed ratio constant section 103 in the middle of 203 and the speed ratio change sections 101 and 102 at both ends of the curve section 203 and is given to the two motors 26 and 29. The photoelectric sensor 47 can detect that the transport vehicle 3 is traveling on the curved portion 203.
As shown in FIG. 11, when the photoelectric sensor 47 detects that the transport vehicle 3 enters the curved portion 203 during acceleration, the speed pattern generator 62 travels as an outer wheel in the first speed ratio change section 101. A speed command is generated and given to the motor corresponding to the wheel so that the acceleration is equal to or less than the acceleration a ₀₁ when entering, and the speed corresponding to the motor corresponding to the inner wheel is higher than the speed of the traveling wheel serving as the outer wheel. A speed command is generated and given so that the speed becomes less than the difference.
In this transport vehicle system 1, when the transport vehicle 3 enters the curved portion 203 while accelerating, a high load is not applied to the motor serving as the outer ring.

(B) If the photoelectric sensor 47 detects the approach to the curve part 203 during acceleration, the speed pattern generation part 62 will be a 1st speed ratio change area, if the motor corresponding to the driving | running | working wheel used as an outer wheel maintains the present acceleration. It determines whether to reach the outer ring maximum velocity V ₂ in the 101. If it is judged not reaching the outer ring maximum velocity V _2, as shown in FIG. 11, the speed pattern generating section 62, the speed command to maintain the current acceleration a ₀₁ to a motor corresponding to the running wheel comprising an outer ring Generate and give.
In this transport vehicle system 1, the calculation load is not increased in the speed pattern generator 62.

(C) If it is determined that the maximum speed is reached in the above case, as shown in FIG. 12, the speed pattern generation unit 62 determines that the traveling wheel that becomes the outer wheel after the end point of the first speed ratio change section 101 is the outer wheel. and generates a speed command such that the maximum velocity V _2, giving a speed command to the motor corresponding to the running wheel comprising an outer ring.
In this transport vehicle system 1, even if the motor corresponding to the traveling wheel serving as the outer wheel maintains the current acceleration a ₀₁ , the outer wheel reaches the outer wheel maximum speed V ₂ within the first speed ratio change section 101. running wheels is prevented from exceeding the outer maximum velocity V _2.

(D) As shown in FIG. 15, if the detection unit detects that the transport vehicle 3 is retreating from the curve unit 203 during deceleration, the speed pattern generation unit 62 is connected to the outer wheel in the second speed ratio change section 102. A speed command is generated and given to the motor corresponding to the traveling wheel to be a deceleration equal to or less than the deceleration a ₀₂ when leaving, and the traveling wheel serving as the outer wheel to the motor corresponding to the traveling wheel serving as the inner ring. A speed command is generated and given so as to be a speed obtained by subtracting the speed difference or more from the above speed.
In this conveyance vehicle system 1, when the conveyance vehicle 3 decelerates from the curved portion 203 while decelerating, a high load is not applied to the motor corresponding to the traveling wheel serving as the outer ring.

(13) 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. In particular, a plurality of embodiments and modifications described in this specification can be arbitrarily combined as necessary.

(A) When the conveyance vehicle enters the curved portion while decelerating If the detection unit detects that the conveyance vehicle 3 enters the curved portion 203 while decelerating, the speed pattern generating unit 62 is the first speed ratio changing section. In 101, a speed command is generated and given to the motor corresponding to the traveling wheel serving as the inner ring, and the inner ring is coupled to the motor corresponding to the traveling wheel serving as the outer ring. A speed command is generated and given so as to be a speed obtained by increasing the speed difference or more than the speed of the traveling wheel.
In the transport vehicle system 1, when the transport vehicle 3 decelerates from the curved portion 203 while decelerating, a high load is not applied to the motor corresponding to the traveling wheel serving as the inner ring.

(B) When the vehicle exits from the curved portion while accelerating If the detection unit detects that the transport vehicle 3 exits from the curved portion 203 while accelerating, the second speed ratio change section In 102, a speed command is generated and given to the motor corresponding to the traveling wheel serving as the inner ring so that the acceleration is equal to or less than the acceleration at the time of leaving, and the traveling corresponding to the inner wheel corresponding to the motor corresponding to the traveling wheel serving as the outer ring. A speed command is generated and given so as to be a speed obtained by increasing the speed difference or more from the wheel speed.
In the transport vehicle system 1, when the transport vehicle 3 accelerates and exits from the curved portion 203, a high load is not applied to the motor corresponding to the traveling wheel serving as the inner ring.
(C) In the said embodiment, although the conveyance vehicle detected the start and completion | finish of the curve part with the sensor, this invention is not limited to this. For example, the conveyance vehicle may make a software determination using an encoder.
(D) In the said embodiment, although the reflective tape was provided continuously along the curve part, this invention is not limited to this. The reflective tape may be provided intermittently.
(E) In the above embodiment, 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.
(F) In the above 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.
(G) The type of combination of the detected portion and the sensor and the detection purpose are not limited to the above embodiment.
(H) The installation position and the number of the detection target parts are not limited to the above embodiment.
(I) In the above embodiment, the left-right speed difference command is formed using the compensation speed ratio table, but the left-right speed difference command may be formed using the reference speed ratio table. Even in that case, the speed pattern generation unit gives the first motor and the second motor the speed command created based on the ideal travel locus when the transport vehicle travels along the curved portion. The front guide roller pair and the rear guide roller pair are unlikely to contact the guide rails.
(J) In the above embodiment, the parameters for servo tracking compensation are response and deviation, but may be either one.
(K) In the above-described embodiment, the description has been given of the transport vehicle system in which the driving traveling unit is provided on the front side of the vehicle body and the driven traveling unit is provided on the rear side, but the present invention is not limited thereto. For example, the present invention can also be applied to a structure in which a front and both sides are drive travel units to form a four-wheel drive carriage. In this case, it is preferable that each drive unit independently creates a speed command for the left and right motors. In addition to the four-wheel drive cart, the present invention can be applied to a six-wheel drive cart and an eight-wheel drive cart.
(L) In the above embodiment, the control operation has been described for all combinations of entry and exit, acceleration and deceleration. However, it is not necessary for all the control operations to be realized in one transport vehicle.

  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 Transport vehicle system 2 Track 3 Transport vehicle 4 Travel rail 4a 1st travel rail 4b 2nd travel rail 6 Guide rail 6a 1st guide rail 6b 2nd guide rail 11 Reflective tape 11a Starting end 13 Bar code 14 Magnetic mark 15 Transport vehicle Body (car body)
18 Drive Traveling Section 19 Followed Traveling Section 20 Main Body Frame 21 First Drive Wheel Unit 22 Second Drive Wheel Unit 23 Main Body Frame 25 First Travel Wheel 26 First Motor 27 First Encoder 28 Second Travel Wheel 29 Second Motor 30 First 2 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 38 Turning axis center 40 1st 3 fixed guide roller 41 4th fixed guide roller 42 3rd branch guide roller 43 4th branch guide roller 44 2nd branch guide roller drive part 47 Photoelectric sensor (detection part)
49 Linear Scale 50 Barcode Reader 52 Car Carrier Controller 54 Controller Main Body 55 Memory 59 Travel Control Unit (Control Unit)
60 Branch Control Unit 61 Route Map 62 Speed Pattern Generation Unit (Speed Command Generation Unit)
63 1st motor control part 64 2nd motor control part 65A 1st error amplification part 65B 2nd error amplification part 66A 1st feedback control part 66B 2nd feedback control part 67A 1st amplifier
67B Second amplifier
70 Standard speed ratio table
71 Reference outer ring speed ratio 73 Reference inner ring speed ratio 80 Stop position 81 Front guide roller pair 83 Rear guide roller pair 85 Front guide roller pair 87 Rear guide roller pair 90 Compensated speed ratio table (speed command conversion table)
91 Compensated outer ring speed ratio 93 Compensated inner ring speed ratio 95 First intermediate point 97 Second intermediate point 98 Curved portion travel locus table 101 First speed ratio change section 102 Second speed ratio change section 103 Speed ratio constant section 201 First straight section 202 Second straight line portion 203 Curve portion 203a Start position 206 Branch portion

Claims (7)

A transport vehicle traveling on a predetermined route;
A control unit for controlling the traveling of the transport vehicle,
The transport vehicle is
The car body,
Two traveling wheels provided on the left and right of the vehicle body;
Two motors respectively connected to the two traveling wheels,
The controller is
The inner / outer wheel speed ratio constant section in the middle of the curved portion and the inner / outer wheel speed ratio at both ends of the curved portion so that a difference in speed occurs between the inner and outer wheels with respect to the reference speed when the transport vehicle travels on the curved portion. A speed command generating unit that generates a speed command in the change section and applies the speed command to the two motors;
A detection unit capable of detecting that the transport vehicle is traveling along a curved portion,
If the detection unit detects that the transport vehicle enters the curved portion during acceleration, the speed command generation unit may detect a motor corresponding to a traveling wheel serving as an outer wheel in the inner / outer wheel speed ratio change section. Generate and give a speed command that gives an acceleration equal to or less than the acceleration at the time of entry, so that the motor corresponding to the traveling wheel that is the inner ring has a speed that is less than the speed difference from the speed of the traveling wheel that is the outer ring. Generate and give a speed command to
Transport vehicle system. The control unit reaches the maximum speed within the inner / outer wheel speed ratio changing section if the detection unit detects an approach to the curved part during acceleration and the motor corresponding to the traveling wheel serving as the outer wheel maintains the current acceleration. A determination unit for determining whether to
The speed command generation unit generates and gives a speed command that maintains the current acceleration to a motor corresponding to a traveling wheel that is an outer wheel if the determination unit determines that the maximum speed is not reached. 2. The transport vehicle system according to 1.   If it is determined that the maximum speed is reached, the speed command generation unit generates a speed command so that a traveling wheel that becomes an outer wheel after the end point of the inner / outer wheel speed ratio change section has a maximum speed, The transport vehicle system according to claim 2, wherein the speed command is given to a motor corresponding to a traveling wheel.   If the detection unit detects that the transport vehicle exits from the curved part during deceleration, the speed command generation unit detects a motor corresponding to a traveling wheel serving as an outer wheel in the inner / outer wheel speed ratio change section. A speed command that generates a deceleration equal to or less than the deceleration at the time of exit is generated and given to the motor corresponding to the traveling wheel that is the inner ring, and the speed that is less than the speed difference from the speed of the traveling wheel that is the outer ring The conveyance vehicle system in any one of Claims 1-3 which produces | generates and gives a speed command so that it may become.   If the detection unit detects that the transport vehicle enters the curved portion during deceleration, the speed command generation unit detects a motor corresponding to a traveling wheel serving as an inner wheel in the inner / outer wheel speed ratio change section. A speed command that generates a deceleration equal to or less than the deceleration at the time of approach is generated and given to the motor corresponding to the outer running wheel, the speed that is greater than the speed difference from the speed of the inner running wheel The conveyance vehicle system in any one of Claims 1-4 which produces | generates and gives such speed command.   If the detection unit detects that the transport vehicle exits from the curved portion during acceleration, the speed command generation unit detects a motor corresponding to a traveling wheel serving as an inner wheel in the inner / outer wheel speed ratio change section. Generate and give a speed command that gives an acceleration equal to or less than the acceleration at the time of leaving, so that the motor corresponding to the traveling wheel that is the outer ring has a speed that is greater than the speed difference from the speed of the traveling wheel that is the inner ring. The transport vehicle system according to claim 1, wherein a speed command is generated and given. A guide rail provided along the path;
The transport vehicle further includes a front guide roller pair and a rear guide roller pair provided on the front side and the rear side of the traveling wheel,
The control unit holds travel locus information in which the front guide roller pair and the rear guide roller pair do not contact the guide rail when the transport vehicle travels a curved portion,
The transport vehicle system according to claim 1, wherein the speed command generation unit creates a speed command conversion table for generating a speed command based on the travel locus information.

Images