JP5083007B2 - Transport system - Google Patents

Description

  The present invention relates to a technical field of a transport system for transporting an object to be transported such as a container in which various substrates for manufacturing semiconductor devices are accommodated on a curved track.

  As this type of transport system, for example, by detecting the number of pulses according to the rotation of the drive wheel by an encoder between the reference members provided in the correction section, and comparing the detected number of pulses with the set number of pulses, There is one that corrects the detection value of the encoder (see Patent Document 1).

JP-A-4-104006

  However, according to the transport system of Patent Document 1 described above, in consideration of the transport vehicle traveling on a plurality of different curves, the encoder is controlled so that an error due to the difference in the curves does not occur in the detection value by the encoder. For example, it is attached to the center of the lower surface of the carrier body. Such an encoder mounting position may limit the configuration of the transport vehicle. For example, when a pair of wheels is arranged on both sides of the main body of the transport vehicle, it is necessary to provide a transmission mechanism that transmits a driving force between one of the pair of wheels and the encoder. In this case, the reliability of the detection value detected via the transmission mechanism may be lacking. Furthermore, since the transmission mechanism is provided, the weight of the transport vehicle increases and the cost may increase.

  The present invention has been made in view of the above-described problems, for example, and an object of the present invention is to provide a transport system that can freely configure transport means such as a transport vehicle having distance detection means such as an encoder.

  In order to solve the above problems, the transport system of the present invention travels along the track, the correction mark attached to the track at a predetermined position, travels along the track, and transports the object to be transported. Reading means for reading the correction mark when passing through a position, transport means having a distance detection means for detecting a travel distance traveled along the track, and the detection based on the read correction mark Correction coefficient acquisition means for acquiring a correction coefficient for correcting a travel distance, and correcting the detected travel distance using the acquired correction coefficient, and specifying the corrected travel distance as a correction distance Correction distance specifying means.

  According to the transport system of the present invention, during operation, a transported object such as FOUP (Front Opening Unified Pod) is laid on a ceiling or a floor, for example, by a transport means such as OHT (Overhead Hoist Transport) or a vehicle. It is transported along a track such as a rail. Then, for example, the correction mark attached to the track is read by the reading unit such as a mark sensor when the transport unit passes (that is, when the correction mark passes by the side of the correction mark or above and below the correction mark). The distance traveled along the track is detected by distance detecting means such as an encoder. Here, the “correction mark” is placed on the trajectory, for example, at a position where a branch or curve starts or a position where the branch or curve ends. Typically, a plurality of such correction marks are attached to a plurality of predetermined positions in the trajectory (for example, before or after each curve, before or after each straight line, before each branch, before each merge, etc.). It is done.

  Here, the trajectory includes, for example, a plurality of curves extending in different directions or having different radii. The distance detecting means provided in the conveying means that travels along such a track is attached, for example, so as to be biased to one side from the center of the conveying means main body. The travel distance detected by such distance detection means includes a detection error due to the difference between the plurality of curves.

  In the present invention, in order to eliminate the detection error, when one correction mark is read by the reading unit, the correction coefficient is acquired by the correction coefficient acquiring unit based on the read correction mark. Here, the “correction coefficient acquisition unit” is a control unit or a conveyance control unit including, for example, a controller, a memory, or the like provided in the conveyance unit or connected to the conveyance unit. The “correction coefficient” is associated with each correction mark, for example, and is set in advance corresponding to a trajectory (for example, a curved trajectory) on the downstream side of each correction mark. Then, the travel distance is corrected by the correction distance specifying means using the acquired correction coefficient, and the corrected travel distance is specified as the correction distance. Here, the “correction distance specifying unit” is included in, for example, a control unit or a conveyance control unit that includes a controller, a memory, or the like that is provided in the conveyance unit or is connected to the conveyance unit. Alternatively, it is configured by a controller or the like independent from the control means and the conveyance control means.

  After this, for example, with respect to the conveyance means based on the correction distance specified by the control means or the conveyance control means including a controller, a memory or the like provided in the conveyance means or connected to the conveyance means, the conveyance means is highly accurate. Control (for example, travel position and stop position, or travel speed) is possible.

  In this way, when the vehicle passes the correction mark attached to the track during traveling, the detection value by the distance detection means is corrected, and the detection error included in the detection value can be eliminated. Therefore, it is possible to freely configure the conveying means regardless of the attachment position of the distance detecting means.

  In one aspect of the transport system of the present invention, the image forming apparatus further comprises storage means for storing the correction coefficient in association with the correction mark, and the correction coefficient acquisition means corresponds to the read correction mark from the storage means. The attached correction coefficient is acquired, and the correction distance specifying means specifies the correction distance by multiplying the detected correction distance by the acquired correction coefficient.

  According to this aspect, when the correction mark is read by the reading unit during traveling, the correction coefficient acquisition unit can be connected to the control unit or the conveyance control unit by communication, or the memory included in the control unit or the conveyance control unit. The correction coefficient associated with the correction mark is acquired from such storage means. Then, a value obtained by multiplying the travel distance detected by the distance detection means (that is, the correction distance) by the correction distance specifying means is calculated. Thus, the travel distance is corrected using the correction coefficient associated with the correction mark. Thereby, it becomes possible to eliminate the detection error included in the travel distance.

  In this aspect, the vehicle control apparatus further includes a travel control unit that controls the travel of the transport unit based on the specified correction distance, and the travel control unit is selected downstream of the read correction mark in the track. When there are a plurality of track portions that can be traveled as one unit, one track portion is selected as the track portion to be traveled from among the plurality of track portions, and the storage means corresponds to each of the plurality of track portions. The correction coefficient is stored in association with each of the plurality of trajectory portions, and when there are the plurality of trajectory portions, the correction coefficient acquiring means stores the selected one of the trajectory portions from the storage means. The associated correction coefficient may be acquired.

  If comprised in this way, at the time of driving | running | working, for example, according to a conveyance instruction | indication according to a conveyance instruction | indication, for example according to a conveyance instruction | indication, one track which should drive | work among several track parts downstream of a correction mark A part is selected. Thereafter, when the correction mark is read by the reading unit, the correction coefficient associated with the selected one orbit portion is selected by the correction coefficient acquiring unit. Thus, the travel distance is corrected using the correction coefficient corresponding to the track portion to be traveled. Thereby, it becomes possible to eliminate the detection error included in the travel distance.

  In another aspect of the transport system of the present invention, the correction coefficient acquisition unit is configured to change the predetermined position indicated by the read correction mark and the state of the track to be traveled from the predetermined position. A correction coefficient is uniquely determined, and the correction distance specifying means specifies the correction distance using the determined correction coefficient.

  According to this aspect, when the correction mark is read by the reading unit during traveling, the correction coefficient is uniquely determined by the correction coefficient acquiring unit. Specifically, first, the state of the track on which the transport unit should travel is read from the position of the correction mark from a database or a storage unit such as a memory in the control unit or the transport control unit. Then, the read state is applied to, for example, a preset determination formula, and the correction coefficient corresponding to the state of the trajectory is uniquely determined. Here, the “orbital state” may be, for example, a curve direction, a curve radius, or the like. Then, the travel distance is corrected by the correction distance specifying means using the determined correction coefficient. In this way, the correction coefficient is uniquely derived based on the position on the track indicated by the correction mark and the state of the track portion on which the transport means should travel from the position. As a result, for example, only the state of the changed track portion needs to be changed as the track is changed, so that the correction coefficient can be easily changed.

  In this aspect, the state may indicate the presence / absence of branching, the curving direction, and the magnitude of the radius of the curve with respect to the track to be traveled.

  With this configuration, the correction coefficient acquisition unit determines whether the track portion to be traveled is curved, for example, from the position of the correction mark, whether the curved direction is the right side or the left side, and the curve. The correction coefficient is determined based on the state of the curve having a radius of either large or small. Thereby, it becomes possible to set a highly accurate correction coefficient.

  In another aspect of the transport system of the present invention, the distance detection unit is directly attached to a drive unit of the transport unit.

  According to this aspect, for example, the travel distance is detected by the distance detection unit directly attached to the drive unit such as a motor. This eliminates the need to provide a transmission mechanism between the drive unit and the distance detection means, thereby increasing the reliability of the detection value and making the distance detection means compact as a whole, and more freely configuring the transport means. It becomes possible.

  The operation and other advantages of the present invention will become apparent from the best mode for carrying out the invention described below.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the configuration of the transport system according to the embodiment will be described. Here, FIG. 1 schematically shows the track and the transport unit according to the embodiment, FIG. 2 shows the mounting position of the measuring unit in the transport unit of FIG. 1, and FIG. The correction coefficient matched with them is shown.

  In FIG. 1, a transport system 100 according to this embodiment includes a track 1, a vehicle 3, a database 9, and a transport controller 10.

  The track 1 is a path for the vehicle 3 to carry the FOUP, and includes a main track 1a and a support track 1b. As shown in FIG. 1, a plurality of correction marks M1 to M4 are attached to the main track 1a, and a correction mark M2 is attached to the support track 1b. Specifically, the main track 1a is branched leftward by the correction mark M1. The track portion branched leftward is the support track 1b. The main track 1a is curved rightward at the correction mark M3, and then travels straight again at the correction mark M4. The support track 1b is curved leftward with the correction mark M1 as a starting point, and then straightened again at the correction mark M2. The FOUP is an example of the “conveyed object” according to the present invention.

  In the present embodiment, the plurality of correction marks M1 to M4 are used to obtain correction coefficients described later, and indicate different identification codes. The identification codes of the correction marks M1 to M4 are read by a mark sensor (to be described later) as the vehicle 3 travels.

  The vehicle 3 is driven by a motor as an example of the “conveying means” according to the present invention, travels along the track 1 and conveys the FOUP. As shown in FIG. 2, the vehicle 3 includes a control unit 5, a mark sensor 6, an encoder 7, and a barcode reader 8.

  The mark sensor 6 is a light projection type sensor having a light projecting portion and a light receiving portion as an example of the “reading unit” according to the present invention, and is attached to the lower surface of the vehicle 3 body. The mark sensor 6 reads an identification code attached to a correction mark (that is, one of the plurality of correction marks M1 to M4) that the vehicle 3 has passed when the vehicle 3 travels, and a signal indicating the read identification code Is sent to the control unit 5.

  The encoder 7 is directly attached to the rotating shaft of a wheel driven by a motor, as an example of the “distance detection means” according to the present invention. The encoder 7 detects a value related to the rotation of the wheel as a travel distance, and sends a signal indicating the detected value (that is, travel distance) to the control unit 5. In the present embodiment, the travel distance sent to the control unit 5 is corrected by the control unit 5.

  Similar to the mark sensor 6, the barcode reader 8 is attached to the lower surface of the vehicle 3 body. The bar code reader 8 reads a bar code BCx (shown in FIG. 2) that the vehicle 3 has passed when the vehicle 3 is traveling, and sends a signal indicating the read bar code to the control unit 5. Based on the read barcode BCx, the traveling of the vehicle 3 is controlled.

  In FIG. 1, the control unit 5 controls each unit of the vehicle 3 in accordance with a conveyance instruction from the conveyance controller 10. As an example of the “correction coefficient acquisition unit” and the “correction distance specifying unit” according to the present invention, the control unit 5 corrects the travel distance from the encoder 7 based on the correction mark indicated by the signal from the mark sensor 6. A distance correction process is performed. The transport controller 10 may include at least some functions of the “correction coefficient acquisition unit” and the “correction distance identification unit” in the control unit 5.

  Regarding the travel distance correction process, specifically, the control unit 5 stores information indicating a correction coefficient associated with a correction mark (or an identification code of the correction mark) from the mark sensor 6 from a track information table 20 described later. get. At this time, when there are a plurality of pieces of acquired information, the control unit 5 selects information indicating a correction coefficient associated with the traveling direction (that is, the downstream trajectory) to travel from the correction mark. In the present embodiment, such a correction coefficient is set by an initial setting that is performed prior to a conveyance instruction from the conveyance controller 10.

  Subsequently, the control unit 5 corrects the travel distance so as to eliminate the detection error of the encoder 7 caused by the difference in curve radius. Specifically, the control unit 5 multiplies the travel distance from the encoder 7 by a correction coefficient acquired from the trajectory information table 20 (or selected one after a plurality of acquisitions). For example, when the travel distance “Sen” and the correction distance “α” are set, the control unit 5 calculates the corrected travel distance “S”, which is the corrected travel distance, by the following formula (1).

          S = α * Sen (1)

  The control unit 5 creates a trajectory information table 20 that stores correction coefficients corresponding to a plurality of trajectory portions in association with correction marks for the trajectory 1 at the time of initial setting. The control unit 5 sends the created trajectory information table 20 to the database 9 via the transport controller 10.

  The control unit 5 also functions as an example of the “travel control unit” according to the present invention, and controls the travel of the vehicle 3 including adjustment of the stop position and the travel speed. Particularly in the present embodiment, the control unit 5 is configured such that, based on a transport instruction from the transport controller 10, the track 3 branches at the track 1 (for example, the position of the correction mark M1 in FIG. 1), and the vehicle 3 That is, the track portion that should travel (advance) after the correction mark M1) is selected. Note that the transport controller 10 may include at least a part of the function of “travel control means” in the control unit 5.

  The transport controller 10 is wirelessly connected to a plurality of vehicles 3 that travel along the track 1 and controls the plurality of vehicles 3 in an integrated manner. The transport controller 10 is connected to the database 9 and enables the vehicle 3 to access the database 9.

  The database 9 stores a trajectory information table 20 from the control unit 5 as an example of the “storage unit” according to the present invention. The database 9 can update the trajectory information table 20 as the state of the trajectory 1 is changed.

  In FIG. 3, specifically, the trajectory information table 20 stores “downstream trajectory” and “correction coefficient” in association with “correction mark (or correction mark identification code)”. The “downstream track” indicates the state of the track 1 where the vehicle 3 can travel downstream from the position of each correction mark (hereinafter referred to as “track portion”). The “correction coefficient” corresponds to each track portion, and indicates a coefficient with which the vehicle 3 travels along each track portion and can correct the travel distance detected by the encoder 7. In the present embodiment, “1” is uniformly set for the straight track portion in the present embodiment, and the value corresponding to the curve radius for the right or left curved track portion. Is set.

As shown in FIG. 1 and FIG. 3, there are two orbital portions of the downstream trajectory of the correction mark “M1”: “straight forward” along the main trajectory 1a and “left curve” along the support trajectory 1b. The correction coefficient corresponding to the orbital portion “left curve” is set to “left curve correction value”. Regarding the downstream track of the correction mark “M2”, there is a “straight forward” track portion along the support track 1b. For the downstream track of the correction mark “M3”, there is a “right curve” track portion along the track 1a, and the correction coefficient corresponding to the track portion “right curve” is set to the “right curve correction value”. . Regarding the downstream track of the correction mark “M4”, there is a track portion of “straight forward” along the main track 1a.
(First travel distance correction process)

  Next, a first travel distance correction process by the control unit 5 functioning as a correction coefficient acquisition unit and a correction distance specifying unit according to the present embodiment will be described with reference to FIGS. 1 and 3. In the first travel distance correction process, the correction coefficient associated with each correction mark is used when the travel distance is corrected.

  In FIG. 1, during traveling, first, any correction mark attached to the track 1 is read by the mark sensor 6. Here, for example, when the correction mark M3 is read, the correction coefficient α “right curve correction value” associated with the correction mark M3 is acquired from the trajectory information table 20 by the control unit 5. Subsequently, the travel distance Sen from the correction mark M3 to the correction mark M4 is detected by the encoder 7. Then, the correction distance S is calculated by the control unit 5 by multiplying the travel distance Sen by the correction coefficient α “right curve correction value”. Thus, during traveling after the correction mark M4, the traveling of the vehicle 3 (that is, the stop position and the traveling speed) is controlled based on the correction distance S.

  On the other hand, for example, when the correction mark M1 is read by the mark sensor 6, the correction coefficient α “1” and the “left curve correction value” associated with the correction mark M1 are retrieved from the trajectory information table 20 by the control unit 5. Is acquired. Then, the control unit 5 selects the downstream track “left curve” (that is, the track portion along the support track 1b) that the vehicle 3 should travel after the correction mark M1, and the downstream track “left curve”. The correction coefficient α “left curve correction value” corresponding to is selected. Subsequently, the travel distance Sen from the correction mark M1 to the correction mark M2 is detected by the encoder 7. Then, the correction distance S is calculated by the control unit 5 by multiplying the travel distance Sen by the correction coefficient α “left curve correction value”. Thereby, the traveling of the vehicle 3 is controlled based on the correction distance S during traveling after the correction mark M2.

  As described above, in the first travel distance correction process of the present embodiment, a position on the track 1 where a branch or curve starts (for example, the correction marks M1 and M3) or a track position where the branch or curve ends (for example, The correction marks M2 and M4) are attached with correction marks, and the detected value of the encoder 7 is corrected using the correction coefficient associated with the correction mark read by the mark sensor 6 during traveling. Thereby, the detection error in the detected value is eliminated regardless of the attachment position of the encoder 7. Therefore, the encoder 7 can be freely attached and the degree of freedom of the configuration of the vehicle 3 is increased.

In the present embodiment, the correction coefficient is acquired from the trajectory information table 20, but may be uniquely determined according to the state of the trajectory 1.
(Second travel distance correction process)

  Next, the second travel distance correction process by the control unit 5 will be described with reference to FIG. FIG. 4 is a flowchart showing a second travel distance correction process which is an example of the travel distance correction process by the control unit 5 according to this embodiment.

  In the first travel distance correction process, a correction coefficient associated with the correction mark is used. In the second travel distance correction process, a correction coefficient that is uniquely derived according to the state of the track portion on which the vehicle 3 should travel is calculated. used.

  The database 9 has a curve information table (not shown) used in the second travel distance correction process in addition to the track information table 20 used in the first travel distance correction process. The curve information table is a plurality of pieces of curve information in association with “correction mark (or correction mark identification code)” and at least one “downstream trajectory” described above as an example of “track state” according to the present invention. “Curve presence / absence”, “Curve direction”, and “Curve radius” are stored. “Presence / absence of curve” indicates whether the track portion to be traveled is “curve” or “go straight” from each correction mark. The “curve direction” indicates whether the direction in which the track portion branched from each correction mark is curved is “right” or “left”. “Curve radius magnitude” indicates whether the radius of the curve to the right or left is “large” or “small”.

  In FIG. 4, during traveling, first, it is determined by the mark sensor 6 whether any correction mark attached to the track 1 has been read (step S50). If the result of this determination is that it has not been read yet (step S50: NO), it enters a standby state until it is read.

  On the other hand, if any correction mark is read as a result of the determination in step S50 (step S50: YES), the control unit 5 determines a track portion on which the vehicle 3 should travel from the position of the read correction mark. While being selected, the curve information associated with the selected orbital portion is acquired from the curve information table. Then, it is determined whether the track portion is straight or curved (step S51). If the result of this determination is that the vehicle is traveling straight (step S51: straight traveling), correction of the travel distance detected by the encoder 7 is unnecessary, and a series of processing is terminated.

  On the other hand, as a result of the determination in step S51, when the track portion is curved (step S51: branch), it is determined whether the curved support track 1b is a right curve or a left curve with respect to the main track 1a. (Step S52). If the result of this determination is a left curve (step S52: left), it is determined whether the angle is large or small for this left curve (step S53). If the angle is small as a result of this determination (step S53: small), the left small curve correction is performed by multiplying the correction coefficient “left small curve correction value” by the travel distance by the encoder 7 (step S53), and a series of processes Is terminated.

  On the other hand, if the angle of the left curve is large as a result of the determination in step S53 (step S53: large), the left large curve correction is performed by multiplying the correction coefficient “left large curve correction value” by the travel distance by the encoder 7 ( Step S55), a series of processing is completed.

  On the other hand, as a result of the determination in step S52, when the branched support track 1b is a right curve with respect to the main track 1a (step S52: right), it is determined whether the angle of the right curve is large or small. (Step S56). If the angle is small as a result of this determination (step S56: small), right small curve correction is performed by multiplying the correction coefficient “right small curve correction value” by the travel distance by the encoder 7 (step S57), and a series of processes. Is terminated.

  On the other hand, when the angle of the right curve is large as a result of the determination in step S56 (step S56: large), the right large curve correction is performed by multiplying the correction coefficient “right large curve correction value” by the travel distance by the encoder 7 ( Step S58), a series of processing is completed.

  Thus, in the second mileage correction process of the present embodiment, the correction coefficient is uniquely determined by determining the direction of the curve and the radius of the curve for at least the curved track portion, and the correction is performed. The detection value of the encoder 7 is corrected using the coefficient. Thereby, the detection error in the detected value is eliminated regardless of the attachment position of the encoder 7. Therefore, the encoder 7 can be freely attached and the degree of freedom of the configuration of the vehicle 3 is increased.

  The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit or concept of the invention that can be read from the claims and the entire specification.

It is a schematic diagram which shows the track | orbit and conveyance means which concern on embodiment. It is a bottom view of the conveyance means which shows the attachment position of the distance detection means which concerns on embodiment. It is a table | surface which shows the track | orbit information table of the memory | storage means which concerns on embodiment. It is a flowchart which shows an example of the travel distance correction process by the conveyance system which concerns on embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Track | orbit, 3 ... Vehicle, 5 ... Control part, 6 ... Mark sensor, 7 ... Encoder, 9 ... Database, 10 ... Transfer controller, 100 ... Transfer system

Claims (4)

Orbit,
A correction mark placed at a predetermined position in the trajectory;
A reading unit that travels along the track to transport the object to be transported, and that reads the correction mark when passing through the predetermined position, and a distance detection unit that detects a travel distance traveled along the track. Conveying means having,
Correction coefficient acquisition means for acquiring a correction coefficient for correcting the detected travel distance based on the read correction mark;
Correction distance specifying means for correcting the detected travel distance using the acquired correction coefficient, and specifying the corrected travel distance as a correction distance ;
(I) the correction coefficient, and (ii) a downstream trajectory indicating a state of a portion of the trajectory in which the transport unit can travel downstream from each position of the correction mark, in association with the correction mark. Storage means for storing
With
The correction coefficient acquisition means acquires at least one of the correction coefficients associated with the read correction mark from the storage means, and when there are a plurality of the acquired correction coefficients, the read correction coefficient Obtaining one correction coefficient corresponding to the downstream track indicating the state of the portion of the track to be traveled from the predetermined position indicated by the mark;
The correction distance specifying means specifies the correction distance by multiplying the detected travel distance by the acquired correction coefficient,
The downstream trajectory indicates any one of “straight”, “left curve” and “right curve” as the state,
The correction coefficient is “1” when the downstream trajectory indicates the “straight forward” and the radius of the curve when the downstream trajectory indicates the “left curve” and the “right curve”. A transport system characterized by corresponding values . A travel control means for controlling the travel of the transport means based on the specified correction distance;
When there are a plurality of portions of the track that can alternatively travel on the downstream side of the read correction mark in the track, the travel control means is a track to travel among the portions of the plurality of tracks. The transportation system according to claim 1 , wherein a portion of one orbit is selected as the portion of. Orbit,
A correction mark placed at a predetermined position in the trajectory;
A reading unit that travels along the track to transport the object to be transported, and that reads the correction mark when passing through the predetermined position, and a distance detection unit that detects a travel distance traveled along the track. Conveying means having,
Correction coefficient acquisition means for acquiring a correction coefficient for correcting the detected travel distance based on the read correction mark;
Correction distance specifying means for correcting the detected travel distance using the acquired correction coefficient, and specifying the corrected travel distance as a correction distance ;
(I) the correction mark, and (II) the presence or absence of a curve in a form corresponding to the downstream track indicating the state of the portion of the track where the transport means can travel downstream from each position of the correction mark, Storage means for storing the direction of the curve and the magnitude of the radius of the curve as curve information;
With
The correction coefficient acquisition unit is configured to transfer the read correction mark and the downstream track indicating the state of the portion of the track to be traveled from the predetermined position indicated by the read correction mark from the storage unit. The conveyance system characterized by acquiring the said curve information matched, and acquiring by determining the said correction coefficient uniquely according to this acquired curve information . It said distance detection means, the conveying system according to any one of claims 1 to 3, characterized in that mounted directly to the drive portion of the conveying means.

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