Conveyance system, conveyance method, and article manufacturing method

Abstract

To suppress vibration and positional deviation of a carriage caused by competition of current control by control sections for controlling each of two conveyance modules adjacent to each other.SOLUTION: A conveyance system includes: a conveyance path which is constituted of at least two conveyance modules; a carriage which moves on the conveyance path; a control section which is provided in each of the two conveyance modules and drives the carriage by a driving command; and a sensor which is provided in each of the two conveyance modules. The driving command is corrected by a distance between the sensors provided in each of the two conveyance modules.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to the transportation of dollies, and more specifically to a transportation system using moving magnet type linear motor (MM type linear motor) technology. [Background technology]

[0002] Generally, in manufacturing sites where factory automation is used to assemble industrial products, a conveying system is used to convey parts and the like between a plurality of stations.

[0003] In recent years, a transport system in which the transport route is divided into multiple control zones, a control device is placed in each control zone, and a cart runs between the control zones has become widely used because it is superior in terms of production efficiency.

[0004] Such a transport system is generally composed of a plurality of lower control units which control the respective control zones, and a higher control unit which is connected to the plurality of lower control units via a communication system.

[0005] The conveying system of Patent Document 1 discloses a method in which a drive command generated by a higher-level control unit is sent in advance to a lower-level control unit, and the higher-level control unit sends conveying commands to the lower-level control units all at once, thereby executing the drive commands sent to the lower-level control units. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2015-202793 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the technology of Patent Document 1, when the interval between the transport modules deviates from a predetermined value and the carriage passes the boundary between the two transport modules, the speed fluctuates and the carriage vibrates. Also, when the carriage is stopped at a position straddling the boundary between the two transport modules, the desired stopping position accuracy is not met, or the carriage cannot be stopped completely within the desired time.

[0008] The present invention has been made in consideration of the above circumstances, and has an object to provide a transport means that enables transporting a cart with high precision. [Means for solving the problem]

[0009] The conveying system of the present invention comprises: a transport path consisting of at least two transport modules; A cart that moves along the transport path; a control unit provided in each of the two transfer modules and configured to drive the carriage in response to a drive command; a sensor provided in each of the two transfer modules; The drive command is corrected based on a distance between sensors provided in each of the two transport modules.

[0010] The transport method of the present invention includes the steps of: moving the carriage along the first transport module in response to a first drive command; moving the carriage across the first transport module and the second transport module in response to the first drive command and the second drive command; a method for transporting a carriage, the method comprising: moving the carriage along the second transport module in response to the second drive command, the method comprising: The second drive command is characterized in that it is corrected based on a distance between a first sensor provided in the first transport module and a second sensor provided in the second transport module.

[0011] The method for manufacturing an article of the present invention is a method for manufacturing an article using the above-mentioned conveying system and at least one process device, transporting the carriage to the process device by the transport system; The process device performs a predetermined process on the workpiece on the carriage, thereby manufacturing the article. Effect of the Invention

[0012] According to the present invention, it is possible to suppress vibrations and displacement of the carriage caused by conflicting current controls by control units that respectively control two adjacent transport modules. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic configuration diagram of a transport control system according to a first embodiment. [Diagram 2] FIG. 2 is a schematic diagram illustrating the configuration of a transport module and a carriage according to the first embodiment. [Diagram 3] 4 is a transportation profile of one carriage in the first embodiment. [Figure 4] 4 is a transportation profile for a plurality of carriages in the first embodiment. [Diagram 5] FIG. 4 is a flow diagram of a cycle operation of the first embodiment. [Figure 6] FIG. 1 is a schematic configuration diagram of a manufacturing system according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] [First embodiment] FIG. 1 is a schematic diagram of a part of a cart transport system 1 including a transport path, a cart, a lower control unit (sometimes referred to as a control unit or a first control unit), and a higher control unit (sometimes referred to as a second control unit). Here, in FIGS. 1 to 3, the X-axis is taken along the transport direction of the cart, the Z-axis is taken vertically to the stand on which the transport module is placed, and the Y-axis is taken perpendicularly to the X-axis and the Z-axis. In this specification, this coordinate system may be referred to as a global coordinate system. Also, the lower control unit (sometimes referred to as a control unit or a first control unit) and the higher control unit (sometimes referred to as a second control unit) may be one control unit.

[0015] The cart transport system 1 has a transport path 100 consisting of multiple transport modules 101 connected to each other and arranged on a frame, and multiple lower level control units 102 connected to each of the multiple transport modules 101 and controlling the connected transport modules 101. The cart transport system 1 also has a higher level control unit 104 that controls the multiple lower level control units 102 via a network 103, and multiple carts 105 that carry workpieces 109 on the transport path 100.

[0016] The multiple lower control units 102 are communicatively connected to a higher control unit 104 via a network 103, and each includes a memory 110 for storing drive commands sent from the higher control unit 104. Each lower control unit 102 is responsible for controlling the transport module 101 to which it is connected, and performs drive control of the carriages 105 on or entering the transport module 101 in the order of their respective drive commands stored in the memory 110.

[0017] The cart transport system 1 is used together with a process equipment group 106 consisting of a plurality of process equipment, and a plurality of carts 105 receive power from a transport module 101 to move along a transport path 100 and transport objects to be processed (workpieces) 109 to each process equipment. Here, each process equipment of the process equipment group 106 is connected to one another via a process equipment network 107 and controlled by a process control unit 108. In addition, the process control unit 108 is connected to a higher-level control unit 104 and exchanges information with each other.

[0018] 1 is a part of the entire transport path, and for the sake of simplicity, only five transport modules 101a-101e, lower level controllers 102a-102e, and three carriages 105a-105c are illustrated. The numbers of transport modules, lower level controllers, and carriages are not limited to these.

[0019] Although the details will be described later, the driving commands for controlling the dolly 105 that has entered the transport module 101 by the lower control unit 102 are stored in the memory 110 of the lower control unit 102 in order. For example, in FIG. 1, the dolly 105c is first stopped on the transport module 101c, then the dolly 105b passes over the transport module 101c, and then the dolly 105a stops on the transport module 101c. Also, the memory 110c of the lower control unit 102c stores the driving commands "1: discharge", "2: pass", and "3: stop" in order. The lower control unit 102c applies the driving command "1: discharge" to the dolly 105c on the transport module 101c to discharge the dolly 105c, and then applies the driving command "2: pass" to the dolly 105b that has entered the transport module 101c to pass the dolly 105b. Then, the subordinate control unit 102c applies the drive command "3: stop" to the cart 105c that next enters the transport module 101c, thereby stopping the cart 105c.

[0020] FIG. 2 shows two transport modules 101a, 101b and one carriage 105 and will be described in detail.

[0021] Fig. 2(A) is a view of the carriage 105 and the transport modules 101a and 101b as viewed from the Y-axis direction, and Fig. 2(B) is a view of only the carriage 105 as viewed from the Y-axis direction. Also, Fig. 2(C) is a view of the transport module 101a and the carriage 105 as viewed from the X-axis direction.

[0022] As shown in FIG. 2(A) and (C), the transport module 101a arranged on the platform 212 includes a module housing 201a, encoders 202aa to 202ac, a coil group 203a, and a guide rail 204a, and is connected to the lower control unit 102a. The transport module 101b includes a module housing 201b, encoders 202ba to 202bc, a coil group 203b, and a guide rail 204b (not shown), and is connected to the lower control unit 102b. In this embodiment, an example using the encoders 202aa to 202bc is shown, but the present invention is not limited to this. Any known sensor can be used as long as it can detect the position of the dolly 105. In this specification, the encoders 202aa to 202bc may be referred to as sensors 202aa to 202bc. A power source (not shown) is connected to the lower control unit 102a. The number and mounting positions of the sensors 202aa to 202ac in the transport module 101a are appropriately adjusted depending on the size of the carriage 105 and the transport module 101a, the accuracy of position detection of the carriage 105, etc. The same applies to the configuration of the other transport modules 101. Specifically, the sensors are mounted over the entire transport path 100 so that the interval between any adjacent sensors is shorter than the length of the scale 206.

[0023] As shown in Figures 2(B) and (C), the carriage 105 includes a top plate 205, a scale 206, a plurality of permanent magnets 207 (sometimes referred to as a magnet array), a permanent magnet bracket 208, a workpiece holding mechanism 209, a scale bracket 210, and a guide block 211.

[0024] The permanent magnet bracket 208, workpiece holding mechanism 209, scale bracket 210 and guide block 211 are attached to a top plate 205, and a plurality of permanent magnets 207 are attached to one or both sides of the permanent magnet bracket 208. In addition, the scale 206 is attached to the scale bracket 210, and the workpiece holding mechanism 209 holds the workpiece 109 on the top plate 205.

[0025] The guide block 211 of the cart 105 is guided by the guide rail 204 of the conveying module 101, and the cart 105 is driven by the electromagnetic force generated between it and a group of coils 203 attached to the module housing 201, and is conveyed along the conveying path 100 (X-axis).

[0026] For example, the sensors 202aa to 202ac of the transport module 101a are attached to a plurality of positions on the module housing 201a so that the gap between the scale 206 of the carriage 105 is constant. The sensors 202aa to 202ac are attached at appropriate intervals so that the carriage 105 can be detected wherever the carriage 105 is located in the transport module 101a.

[0027] The sensors 202aa to 202ac read the pattern of the scale 206 of the dolly 105 and detect the position of the dolly 105 in the X direction (X position) as a relative position from the sensors 202aa to 202ac. The sensors 202aa to 202ac then output information about the position of the dolly 105a to the lower control unit 102a, and the lower control unit 102a can know where the dolly 105 is located on the transport module 101a that it is in charge of based on this information. The lower control unit 102a may transmit this information to the upper control unit 104.

[0028] In this embodiment, the sensors 202aa to 202bc are of absolute type, and the scale 206 is an absolute type sensor that can be read, but the present invention is not limited to this.

[0029] W shown in FIG. 2(b) is the driving width, which is the width of the magnet array 207 in the carriage transport direction (X direction).

[0030] For example, the center C1 of the width of the dolly 105 in the transport direction (X direction) is set as a reference position, and the position of the dolly 105 is defined as the coordinates of the reference position C1.

[0031] In controlling the carriage 105, the host control unit 104 controls the entire transport system using one coordinate system (the global coordinate system described above).

[0032] On the other hand, the lower level control units 102a to 102e perform control using individual coordinate systems (called local coordinate systems) set for each unit.

[0033] Of the sensors provided in each transport module that send signals to each subordinate controller, for example, the position 202aa, 202ba of the leftmost sensor is defined as the origin of the local coordinate system of the corresponding transport module.

[0034] The host control unit 104 holds, for example, the position (design value) of the origin of the local coordinate system where the leftmost sensor of each transfer module should be located.

[0035] The lower-level controller 102 applies a current to the coil group 203 of the transport module 101 it is responsible for and controls the amount of current based on the drive command stored in its own memory 110. As a result, the lower-level controller 102 transports the cart 105 to a predetermined position at a predetermined speed on the transport module 101 it is responsible for, or stops the cart 105.

[0036] Furthermore, the lower level control unit 102 can detect that the carriage 105 has entered the transport module 101 it is responsible for from the sensors 202aa-202bc of the transport module 101 it is responsible for. Then, when the entered carriage 105 reaches a predetermined position of the transport module 101 it is responsible for, the lower level control unit 102 performs transport control of the carriages 105a-105e based on the control commands in the memories 110a-110e. The predetermined position may be a boundary between the transport modules 101. Furthermore, the lower level control unit 102 may perform control over the carriage 105 when the sensor 202 of the transport module 101 it is responsible for reads the scale 206 of the carriage 105.

[0037] 2A, when the cart 105 moves from left to right on the page, and the sensor 202aa of the transport module 101a reads the scale 206 of the cart 105, the lower-level controller 102a controls the cart 105 on the transport module 101a. When the cart 105 enters the transport module 101b and the sensor 202ba of the transport module 101b reads the scale 206 of the cart 105, the lower-level controller 102b controls the cart 105 on the transport module 101b.

[0038] Here, we will explain the "single group transport command." The single group transport command is a drive command sent simultaneously at the same time from the upper control unit 104 to all or a group of multiple lower control units 102 that control all or a part of a group of carts made up of multiple carts 105. In other words, the single group transport command is a signal to simultaneously start operation (cart drive control) of the multiple lower control units 102 that received it.

[0039] When the multiple lower control units 102 receive a group transport command from the upper control unit 104, they apply the drive commands stored in the memory 110 in sequence to the carts 105 on or entering the transport module 101 they are responsible for, and begin drive control of the carts 105.

[0040] Next, a method of transporting one carriage 105 between a plurality of transport modules 101 will be described with reference to Fig. 3. Fig. 3(A) is a schematic diagram showing that one carriage 105 is transported across two transport modules 101a to 101b. Fig. 3(B) is a transport profile of the carriage 105 with the X position of the carriage 105 on the vertical axis and time t on the horizontal axis, and Fig. 3(C) is a speed profile of the carriage 105 with the speed v of the carriage 105 on the vertical axis and time t on the horizontal axis.

[0041] The transport profile P0 is a drive profile for moving the carriage 105 from the departure position S1 to the arrival position A1 by the trapezoidal drive 201 at a maximum speed v1 and a required time t5, and the coordinate values ​​are defined on the global coordinate system X.

[0042] The upper control unit 104 generates a conveyance profile P0 and extracts partial profiles (drive commands) P1 and P2 therefrom.

[0043] In this configuration, since the lower control units 102a to 102b connected to the two conveyance modules 101a to 101b are involved in the control of the conveyance of the carriage 105, the partial profile (drive command) P1 is sent to the lower control unit 102a. Then, the partial profile P2 is sent to the lower control unit 102b. As a result, the drive command "1: discharge" which is the partial profile P1 is stored in advance in the memory 110a of the lower control unit 102a. And the drive command "1: stop" which is the partial profile P2 is stored in advance in the memory 110b of the lower control unit 102b.

[0044] The carriage 105 initially stops on the conveyance module 101a, and the lower control units 102a to 102b receive a group of conveyance commands from the upper control unit 104 and start the conveyance control of the carriage 105.

[0045] The lower control unit 102a applies the drive command "1: discharge" stored in the memory 110a to the carriage 105 and conveys the carriage 105 toward the adjacent conveyance module 101b. At this point, although the lower control unit 102b has received a group of conveyance commands, it does not operate because the carriage 105 has not entered the conveyance module 101b which it is in charge of.

[0046] After that, when the carriage 105 reaches the boundary between the conveyance modules 101a and 101b, or when the sensor 202ba of the conveyance module 101b reads the scale 206 of the carriage 105, the control of the carriage 105 transfers from the lower control unit 102a to the lower control unit 102b.

[0047] After that, the lower control unit 102b applies the drive command "1: stop" stored in the memory 110b to the carriage 105 and stops the carriage 105 at a predetermined position. In this way, the carriage 105 is conveyed across the conveyance modules 101a to 101b.

[0048] Next, a description will be given of the transportation profile 301 for one cart 105. The transportation profile 301 is a profile related to drive control by one or more lower level control units 102a to 102b from when one cart 105 starts moving from a stopped state until it stops again.

[0049] As an example, a transport profile P0 for one carriage 105 is shown in FIG.

[0050] R1 is a value indicating the position (design position) of the sensor 202aa in the global coordinate system, and is held in the upper control unit. The actual position of the sensor 202aa is the origin of the transfer module 101a.

[0051] Similarly, R2 is a value indicating the position (design position) of the sensor 202ba as a position in the global coordinate system, which is held in the upper control unit. The position (design position) of the sensor 202ba as a position becomes the origin of the transfer module 101b.

[0052] Q1 and Q2 indicate the origins in the local coordinate systems of the transport modules 101a and 101b, respectively.

[0053] The origin of the local coordinate system is the time when the carriage 105 starts to drive, and the origin of the local coordinate system is the installation positions of the sensors 202aa and 202ba on the upstream side of each transport module.

[0054] Q1 is the origin of the local coordinate system of the transport module 101a thus determined, and Q2 is the origin of the local coordinate system of the transport module 101b.

[0055] In this embodiment, the origin of the local coordinate system of the transport module 101a located most upstream is set as the origin of the global coordinate system, but this is not limiting.

[0056] The motion of the carriage can be expressed in the form of time versus position, time versus speed, and position versus speed, which are mutually convertible. Therefore, any of these expression forms may be used to express the drive commands P1 and P2, which are partial profiles, but in this embodiment, an example of position versus speed is shown.

[0057] The carriage 105 first stops on the transport module 101a, and is then transported to the transport module 101b and stops there. As shown in Fig. 3(B), the transport profile P0 starts from a point 301a and ends at a point 301f.

[0058] First, the carriage 105 starts energizing the coil group 203a of the transport module 101a from a stopped state at time t0. As a result, the carriage 105 starts moving at a speed v0, reaches a speed v1 (>v0) at time t1, and reaches the boundary between the two transport modules 101a and 101b at time t2.

[0059] At time t2, the carriage 105 starts energizing the coil group 203b of the transport module 101b and enters the transport module 101b, maintaining the speed v1 until time t4, then decelerating and stopping at a speed v0 on the transport module 101b at time t5. Meanwhile, at time t3, energization of the coil group 203a of the transport module 101a is stopped.

[0060] In FIG. 3B, point 301a is a point on the transport profile P0 at time t0, point 301b is a point on time t1, point 301c is a point on time t2, point 301d is a point on time t3, point 301e is a point on time t4, point 301f is a point on time t5.

[0061] 3B, X is a coordinate system (global coordinate system) of positions when viewed from a common coordinate system for the transport modules 101a to 101b. Xa and Xb are individual coordinate systems (local coordinate systems) that are coordinate systems of positions within the transport modules 101a and 101b, respectively. And v represents the speed of the carriage 105.

[0062] X, Xa, Xb, and v can each represent an attribute using a point on the transport profile P0 as an argument. For example, "X(301a)" represents the X coordinate of the carriage 105 at point 301a on the transport profile 301, and "Xa(301a)" represents the Xa coordinate of the carriage 105 at point 301a on the transport profile 301. Similarly, "V(301a)" represents the velocity of the carriage 105 at point 301a on the transport profile 301.

[0063] Next, the trapezoidal drive profile will be described. The trapezoidal drive profile is a profile in which the drive control of the carriage 105 in each transport module 101 after the carriage 105 enters the transport module 101 is expressed by one or more trapezoidal drive elements.

[0064] Here, a "trapezoidal drive element" is a combination of the start position, end position, start position speed, and end position speed of the carriage 105. For simplified description, one trapezoidal drive element is enclosed in parentheses () and expressed as (start position, end position, start position speed, end position speed). Also, the trapezoidal drive elements related to one carriage 105 arranged in chronological order and enclosed in curly brackets {} constitute the trapezoidal drive profile for that carriage 105.

[0065] Furthermore, when one group transport command is sent from the upper level control unit 104, one or more carriages 105 pass or stop over one transport module 101. Therefore, one or more trapezoidal drive profiles for one transport module 101 are enclosed in square brackets [ ] and referred to as a "module drive command" or simply a "drive command" for the transport module 101.

[0066] A drive command for each transport module is transmitted from the upper control unit 104 to the lower control unit 102 and stored in the memory 110. After that, when the lower control unit 102 receives a group transport command from the upper control unit 104, it controls the drive of the carriage according to the trapezoidal drive profile of the drive command stored in the memory.

[0067] For example, in FIG. 3B, before the one-group transport command is transmitted, the drive command P1 sent from the upper controller 104 to the lower controller 102a of the transport module 101a is written as in the following formula 1. [{(Xa(301a), Xa(301b), v0, v1), (Xa(301b), Xa(301c), v1, v1) , (Xa(301c), Xa(301d), v1, v1)}] …Formula 1 When the lower level control unit 102a receives this drive command P1, it stores it in the memory 110a.

[0068] Similarly, a drive command P2 sent to the lower control unit 102b of the transport module 101b is written as in the following formula 2. [{(Xb(301c), Xb(301d), v1, v1), (Xb(301d), Xb(301e), v1, v1) , (Xb(301e), Xb(301f), v1, v0)}] …Formula 2 When the lower level control unit 102b receives this drive command P2, it stores it in the memory 110b.

[0069] When the lower level controllers 102a to 102b receive a group transport command from the upper level controller 104, the transport of the carriage 105 is started, and the carriage 105 departs from the transport module 101a and stops on the transport module 101b.

[0070] Here, for points 301c and 301d on the transport profile P0, a drive command expressed in the individual coordinate system (local coordinate system) of the transport module 101a, Xa(301c), Xa(301d), is sent to the subordinate controller 102a for the transport module 101a. Also, for the transport module 101b, a drive command expressed in the individual coordinate system (local coordinate system) of the transport module 101b, Xb(301c), Xb(301d), is sent to the subordinate controller 102b. In other words, between points 301c and 301d on the transport profile P0, the two transport modules are driven by the coils of both transport modules based on position information expressed in their respective local coordinate systems.

[0071] While the carriage 105 is in a position straddling the boundary between the transport modules 101a and 101b, i.e., at a position between coordinates Xb-W / 2 and Xb+W / 2, both the coil group 203a of the transport module 101a and the coil group 203b of the transport module 101b are energized and controlled.

[0072] However, there are cases where the distance between each of the transport modules (for example, between 101a and 101b) that connects the transport path consisting of the multiple transport modules 101 that are connected to each other and arranged on the platform is deviated from a predetermined value. If the distance between the transport modules 101a and 101b deviates from the design value (predetermined value), the position of the sensor of the transport module 101b relative to the sensor on the transport module 101a (the distance between the sensors) deviates from the predetermined position. In other words, if the distance between adjacent transport modules (the distance between the sensors) deviates from the predetermined value, the positions of the carriages of the two control units that obtain position information from the two sensors 202ac and 202ba that are closest to the boundary between the transport modules 101a and 101b in particular deviate. As a result, the current controls by the two lower control units that are in charge of the two adjacent transport modules compete with each other, causing vibrations and positional deviations of the carriages. In order to suppress this vibration and positional deviation of the carriages, the position of the partial profile (drive command) P2 is corrected.

[0073] According to this embodiment, it is possible to suppress vibrations and displacement of the carriage caused by conflicting current controls by the control units that respectively control two adjacent transport modules.

[0074] Next, a method of correcting the partial profile (drive command) P2 will be described. In this embodiment, the transport modules 101a and 101b are taken as an example, but the present invention is not limited to this.

[0075] First, after a plurality of transfer modules are connected to each other and arranged on a stand, the distance D12 between the sensors of the plurality of transfer modules (for example, the distance from the sensor 202ac to the sensor 202ba) is measured in advance.

[0076] There are various possible measurement methods, but one example is a method using two sensors 202ac and 202ba that are closest to the boundary between the transport modules 101a and 101b. Specifically, the cart 105 is stopped at a position that straddles the transport modules 101a and 101b. The lower control units 102a and 102b read the scale 206 using the sensors 202ac and 202ba, respectively, to obtain the respective position information. The distance D12 between the sensors 202ac and 202ba can be measured by calculating the difference between the two pieces of position information thus obtained. This measurement may be performed before the start of operation of the transport system, or may be performed by stopping the cart 105 at the above position at any timing during operation. In addition, if a glass scale is used as the scale 206, the individual differences of the scales can be almost ignored, and the value measured on one cart can be applied to all the carts. In other words, after the above measurement is performed on the cart 105, it can be used for the above correction of the next cart that passes through this position.

[0077] The distance D12 between the transport modules 101a and 101b thus determined is stored in the upper control unit, and this value is used to perform correction when the upper control unit 104 extracts a partial profile (drive command) P2 generated from the transport profile.

[0078] Specifically, for example, if the design value of the distance between two sensors 202ac and 202ba sandwiching the boundary between adjacent transfer modules is D0, the deviation amount of the distance between the sensors 202ac and 202ba from the design value D0 can be calculated as ΔD12 = D12 - D0. Note that the position of the sensor 202aa, which is the origin of the transfer module 101a, is the true position. ΔD12 is larger than 0 (positive value) when D12 is larger than D0, and is smaller than 0 (negative value) when D12 is smaller than D0.

[0079] Specifically, the true position R2a of the sensor 202ba in the global coordinate system can be calculated as R2a=R2+ΔD12. If the true position of the sensor 202ba is known, the true origin Q2a of the local coordinate system Xb of the transport module 101b can be determined to be a position shifted by a distance ΔD12 from the original position Q2.

[0080] The upper control unit 104 uses the thus determined corrected local coordinate system when extracting the partial profile (driving command) P2 and converting it into local coordinates, thereby making it possible to correct the deviation in the position of the cart recognized by the two control units.

[0081] Specifically, since the origin Q2 is shifted by a distance ΔD12, ΔD12 can be subtracted from the position value of the partial profile (drive command) before correction. That is, for example, the position A in the local coordinate system Xb has a correction value of Xb(A-ΔD12). Here, as described above, ΔD12 can be a positive value or a negative value. Therefore, subtracting ΔD12 from the position value of the partial profile (drive command) means that if the value of ΔD12 is, for example, +2, then 2 is subtracted from A. However, if the value of ΔD12 is, for example, -2, then 2 is added to A.

[0082] The above-mentioned drive command P2 is written as in Equation 2 below. [{(Xb(301c), Xb(301d), v1, v1), (Xb(301d), Xb(301e), v1, v1) , (Xb(301e), Xb(301f), v1, v0)}] …Formula 2

[0083] Before being sent from the upper control unit 104 to the lower control unit 102b, P2 is corrected in the upper control unit to a drive command P2' described as in the following Equation 3, and then sent to the lower control unit 102b. [{(Xb (301c-ΔD12), Upon receiving this drive command P2', the lower level control unit 102b stores it in the memory 110b.

[0084] In the above description, an example has been given in which a carriage is transported from one transport module to an adjacent transport module.

[0085] When controlling a carriage that moves through three or more transport modules, correction can be made by adding up the deviation in distance between two sensors that sandwich the boundary between adjacent transport modules.

[0086] In the transfer starting from the transfer module 101a, passing through the transfer module 101b, and arriving at the transfer module 101c, in addition to the correction of the partial profile (driving command) P2 described above, the correction of the partial profile (driving command) P3 (not shown) is performed. The deviation ΔD23 (not shown) of the distance between the sensors 202bc and 202ca from the design value is calculated.

[0087] Next, the true position R3a (not shown) of the sensor 202ca is calculated as R3a = R3 + ΔD23, and the partial profile (drive command) is extracted and corrected in the same manner as the above correction. At this time, since the sensor 202bc is shifted by ΔD12 as described above, the drive command is corrected by subtracting (ΔD12 + ΔD23) from each position. In other words, for example, the position A in the local coordinate system Xc has a correction value of Xc(A - (ΔD12 + ΔD23)).

[0088] In order to apply the present invention to the entire transport system, the above-mentioned measurements must be performed at the boundaries of all the transport modules that make up the transport path 100 .

[0089] One way to accomplish this is to have the carriage 105 stop at the boundaries of all the transport modules in sequence and perform the measurements described above.

[0090] However, performing such measurements over the entire transport system using one carriage 105 takes time, which reduces transport efficiency.

[0091] On the other hand, as mentioned above, if a glass scale is used, the manufacturing differences are small and the thermal expansion coefficient is small, so that the individual differences between carriages can be almost ignored. Therefore, by operating multiple carriages in parallel and performing the above-mentioned measurements at the boundaries of multiple transport modules in parallel, the time required for measurements at all of the boundaries of the transport modules can be reduced.

[0092] Next, a module drive command and a group transport command when transporting a plurality of carriages 105a to 105c will be described with reference to FIG.

[0093] FIG. 4A, like FIG. 1, shows a state in which carriages 105a to 105c are initially stopped on transfer modules 101a to 101c among transfer modules 101a to 101e, respectively, and there are no carriages on transfer modules 101d and 101e.

[0094] Thereafter, the lower control units 102a to 102e transport the carriages 105a to 105c in response to the group transport command transmitted from the upper control unit 104. Finally, the carriages 105a to 105c are transported and stopped on the transport modules 101c to 101e, respectively.

[0095] Fig. 4B shows transport profiles 401-403 of the carriages 105a-105c, with the horizontal axis representing time t and the vertical axis representing the X-positions of the carriages 105a-105c. In Fig. 4B, time t0 is the time when a one-group transport command, which will be described later, is sent from the upper controller 104 to the lower controllers 102a-102e of the transport modules 101a-101e.

[0096] The transport profile 401 is a transport profile in which the carriage 105a in the transport module 101a is transported from position P(a) to position P(c) in the transport module 101c. Similarly, the transport profile 402 is a transport profile in which the carriage 105b in the transport module 101b is transported from position P(b) to position P(d) in the transport module 101d. Moreover, the transport profile 403 is a transport profile in which the carriage 105c in the transport module 101c is transported from position P(c) to position P(e) in the transport module 101e.

[0097] In this case, the drive command sent to the subordinate controller 102a of the transport module 101a is written as shown in Equation 4. [{(Xa(401a), Xa(401b), V(401a), V(401b)), (Xa(401b), Xa(401c), V(401b), V(401c))}] …Formula 4

[0098] In addition, the drive command sent to the lower control unit 102b of the transport module 101b is written as the following equation 5, where ΔDb is the distance (deviation) between the sensor on the 101a side of the transport module 101b and the sensor on the 101b side of the transport module 101a. [{(Xb(402a-ΔDb), Xb(402b-ΔDb), V(402a), V(402b)), (Xb(402b), Xb(402c), V(402b), V(402c))}, {(Xb(401c-ΔDb), Xb(401d-ΔDb),V(401c), V(401d)), (Xb(401d-ΔDb), Xb(401e-ΔDb), V(401d), V(401e))}] …Formula 5

[0099] Further, the drive command sent to the lower control unit 102c of the transport module 101c is written as the following formula 6, where ΔDc is the distance (deviation) between the sensor on the 101c side of the transport module 101b and the sensor on the 101c side of the transport module 101b. [{(Xc(403a-(ΔDb+ΔDc)), Xc(403b-(ΔDb+ΔDc)), V(403a), V(403b))}, {(Xc(402c-(ΔDb+ΔDc))), Xc(402d-(ΔDb+ΔDc)), V(402c), V(402d))}, {(Xc(401e-(ΔDb+ΔDc)), Xc(401f-(ΔDb+ΔDc)), V(401e), V(401f)}] …Formula 6

[0100] Further, the drive command sent to the lower control unit 102d of the transport module 101d is written as in the following formula 7, where ΔDd is the distance (deviation) between the sensor on the 101c side of the transport module 101d and the sensor on the 101d side of the transport module 101c. [{(Xd(403b-(ΔDb+ΔDc+ΔDd)), Xc(403c-(ΔDb+ΔDc+ΔDd)), V(403b), V(403c)), (Xd(403c-(ΔDb+ΔDc+ΔDd)), Xb(403d-(ΔDb+ΔDc+ΔDd)), V(403c), V(403d))}, {(Xd(402d-(ΔDb+ΔDc+ΔDd)), Xd(402e-(ΔDb+ΔDc+ΔDd)), V(402d), V(402e)}] …Formula 7

[0101] The drive command sent to the lower control unit 102e of the transport module 101e is written as in the following formula 8, where ΔDe is the distance (deviation) between the sensor on the 101d side of the transport module 101e and the sensor on the 101e side of the transport module 101d. [{(Xe(403d-(ΔDb+ΔDc+ΔDd+ΔDe)), Xe(403e-(ΔDb+ΔDc+ΔDd+ΔDe)), V(403d), V(403d)), (Xe(403e-(ΔDb+ΔDc+ΔDd+ΔDe)), Xe(403f-(ΔDb+ΔDc+ΔDd+ΔDe)), V(403e), V(403f))}] …Formula 8

[0102] Such drive commands are stored in memories 110a-110e of the lower-level controllers 102a-102e, and then at time t0, a group transport command is sent from the upper-level controller 104. Then, the lower-level controllers 102a-102e drive and control the carriages 105a-105c in accordance with the respective drive commands, and transport them to the target positions P(c), P(d), and P(e), respectively.

[0103] Thereafter, at time t11 when all trapezoidal drive profiles in the drive command have been processed, the lower control unit 102a transmits a drive end signal to the upper control unit 104. Similarly, the lower control unit 102b transmits a drive end signal to the upper control unit 104 at time t12, the lower control unit 102c transmits a drive end signal to the upper control unit 104 at time t13, the lower control unit 102d transmits a drive end signal to the upper control unit 104 at time t32, and the lower control unit 102e transmits a drive end signal to the upper control unit 104 at time t33.

[0104] 1 and 4A, the "1: discharge" command is stored at the first position in the memory 110a of the lower control unit 102a, and its substance is the term in the curly brackets {} in formula 4. Also, the "1: discharge" and "2: pass" are stored at the first position and the second position, respectively, in the memory 110b of the lower control unit 102b, and their substances are the term in the first curly brackets {} and the term in the second curly brackets {} in formula 5. Also, the "1: discharge" and "2: pass" are stored at the first position, the second position, and "3: stop" are stored at the third position in the memory 110c of the lower control unit 102c, and their substances are the term in the first curly brackets {}, the term in the second curly brackets {}, and the term in the third curly brackets {} in formula 6, respectively. Furthermore, "1: Pass" is stored at the first position in memory 110d of lower control unit 102d, and "2: Stop" is stored at the second position, and their entities are the term in the first curly bracket {} and the term in the second curly bracket {} in formula 7. And, "1: Stop" is stored at the first position in memory 110e of lower control unit 102e, and its entity is the term in the curly bracket {} in formula 8.

[0105] In this way, the module drive command sent to a certain one of the multiple lower level controllers is a trapezoidal drive profile arranged in the order of the carriages on or entering the transport module managed by the certain lower level controller. The trapezoidal drive profile is a time sequence of the trapezoidal drive elements for the carriages on or entering the transport module managed by the certain lower level controller.

[0106] FIG. 5 is a flow diagram of the operations between the process control unit 108, the upper control unit 104, and the lower control unit 102.

[0107] Generally, in the manufacturing process of industrial products, a plurality of workpieces 109 are transported on a transport path 100, while a plurality of process devices 106 arranged in the order of processes along the transport path 100 sequentially process the workpieces 109.

[0108] Here, a task unit of transporting the workpiece 109 and processing it by the process equipment is called a "cycle operation," and a product is manufactured by repeating this cycle operation.

[0109] First, in step S502, the process control unit 108 collects process information related to the state of the workpieces 109 on each cart 105 and the group of process devices 106. In step S503, the process control unit 108 generates a transport method for the carts in accordance with the collected process information. For example, if there is a workpiece on a group of carts consisting of multiple carts 105 that is not sufficiently machined, the workpiece may be transported to a process for additional processing or to a process for recovery, and so on. Therefore, the transport method for the carts 105 is reviewed for each cycle operation. In step S504, the process control unit 108 transmits the transport method for the group of carts consisting of multiple carts 105 to the upper control unit 104.

[0110] In step S505, the upper control unit 104 receives the transport method of the group of carriages. In step S506, the upper control unit 104 generates a trapezoidal drive profile for each carriage 105 based on the transport method of the group of carriages. In step S507, the upper control unit 104 compiles the drive profiles for each carriage by module and generates a drive command. At this time, the drive command is corrected depending on the distance between the transport modules (the distance between the sensors). In step S508, the upper control unit 104 transmits a corrected drive command having a trapezoidal drive profile to each lower control unit 102.

[0111] In step S509, the lower control unit 102 receives the drive command and stores it in memory. The lower control unit 102 enters a state of waiting for a single group transport command from the upper control unit 104. In step S510, the upper control unit 104 transmits the single group transport command to each lower control unit 102. In step S511, when each lower control unit 102 receives the single group transport command, they simultaneously start drive control of the carts. The lower control unit 102 starts transport of the cart 105 on the transport module 101 it is responsible for, and applies a trapezoidal drive profile to the entering cart 105 to transport or stop the cart 105.

[0112] In step S512, when each of the lower control units 102 has completed application of all trapezoidal drive profiles of the drive commands transmitted from the upper control unit 104, it transmits a drive end signal to the upper control unit 104. In step S513, when the upper control unit 104 receives a drive end signal from each lower control unit 102, it transmits a notification of the completion of transport of the group to the process control unit 108.

[0113] In step S515, the process control unit 108 receives a notification of completion of one group transport from the upper control unit 104. In step S516, the process control unit 108 transmits a control command to the corresponding process equipment of the process equipment group 106 to process the workpiece 109. In this manner, one cycle operation is completed (S517). When one cycle operation is completed, the process control unit 108 starts the next cycle operation (S501 to S517).

[0114] As described above, by correcting the drive command, it is possible to suppress vibrations and misalignment of the carriage caused by competing current controls by two lower-level control units each responsible for two adjacent transport modules.

[0115] In the present embodiment, an example has been shown in which the upper control unit 104 corrects the partial profile (drive command) and sends it to the lower control unit 102, but the present invention is not limited to this.

[0116] For example, the upper controller 104 obtains a deviation ΔD12 of the distance between the transport modules from a design value D0, and sends this value to the lower controller 102, which then holds this value.

[0117] Other lower level control units similarly measure and store the amount of deviation in the distance between the transport modules.

[0118] Thereafter, the upper control unit transmits an uncorrected partial profile (driving command) to each lower control unit, and instructs them to start transport.

[0119] Each of the lower level control units corrects the received partial profile (drive command) with the stored deviation amount and performs current control.

[0120] In the present embodiment, the carriage 105 is driven by an electromagnetic force generated between the carriage 105 and the coil group 203 attached to the module housing 201, and is transported along the transport path 100 (X-axis), but the present invention is not limited to this. The carriage 105 may be provided with a permanent magnet in the module housing 201 and with a coil in the carriage 105, or may be provided with any other transport means capable of driving the carriage along a rail.

[0121] In the embodiment described above, the transport path 100 is physically divided into a plurality of transport modules, and each transport module corresponds to a control zone.

[0122] However, the scope of application of the present invention is not limited to a conveying system configured in this manner, and may be, for example, a single long module housing in which multiple coil groups are installed, with each of these multiple coil groups corresponding to a control zone.

[0123] In the embodiment described above, the measurement is performed after the carriage 105 is stopped at a position straddling adjacent sensors. Stopping the carriage 105 in the middle of the conveyance path 100 in this manner, even for a short time, reduces the conveyance efficiency of the entire conveyance system, and therefore cannot be performed frequently.

[0124] On the other hand, immediately after the start of operation of the transfer system, the gap between the transfer modules becomes misaligned due mainly to thermal expansion, and therefore there is a demand to repeatedly perform the above measurement immediately after the start of operation of the transfer system.

[0125] A method for performing the above measurement without stopping the dolly 105 will be described below with reference to FIG.

[0126] An example will be described in which the distance between the sensors 202ac and 202ba is measured while the carriage 105 is passing through the boundary between the transport modules 101a and 101b.

[0127] When the dolly 105 faces both the sensors 202ac and 202ba, the upper control unit 104 instructs the lower control unit 102a to read position information from the sensor 202ac and at the same time instructs the lower control unit 102b to read position information from the sensor 202ba.

[0128] In this way, by calculating the difference in position information obtained by reading one scale 206 with two sensors 202ac and 202ba, the above measurements can be performed for the transport modules 101a and 101b in the same manner as described in the above embodiment.

[0129] In the measurement method described above, the difference in communication time between the upper control unit 104 and the lower control units 102a and 102b is not taken into consideration. Therefore, this method is applicable only when the speed of the cart 105 is sufficiently slow and the accuracy required for transportation is low.

[0130] A method for solving the problem caused by the difference in communication time will be described below.

[0131] The low level control units 102a and 102b each have an internal clock (not shown). The internal clocks are synchronized by a known method for synchronizing the internal clocks of a plurality of computers connected to a communication system.

[0132] When the carriage 105 reaches the boundary between the transport modules 101a and 101b, the upper controller 104 instructs the lower controller 102a to read position information for a predetermined time using the sensor 202ac, and at the same time, instructs the lower controller 102b to read position information for a predetermined time using the sensor 202ba.

[0133] The lower level control units 102a and 102b each store the position information that it has read for a predetermined period of time in its own position table (not shown) with a time stamp.

[0134] The predetermined time may be approximately the same as the communication delay time of the communication system being used, and typically a few milliseconds is sufficient.

[0135] After the predetermined time has elapsed, the upper controller 104 refers to the position tables of the lower controllers 102a and 102b and calculates the difference in position information for the portions where the timestamp values ​​match, thereby making it possible to perform the above-mentioned measurements for the transport modules 101a and 101b in the same manner as in the embodiment described above.

[0136] Even if the internal clocks of the lower level control units 102a and 102b are synchronized, it is difficult to avoid a gradual discrepancy between the two.

[0137] A commercially available technology that can solve the two problems mentioned above, namely communication delay time and internal clock mismatch, is called distributed clock technology.

[0138] EtherCAT (registered trademark) equipped with a distributed clock function is used as a communication system connecting the upper control unit 104 and the lower control units 102a and 102b. It is also assumed that the upper control unit 104 is set as the master, and the lower control units 102a and 102b are set as slaves.

[0139] In the transport system thus configured, the upper control unit 104 simultaneously instructs the lower control unit 102a to read position information by the sensor 202ac and the lower control unit 102b to read position information by the sensor 202ba, as described above.

[0140] Unlike the above case, the communication system performs signal transmission taking into consideration communication delay times, so that two pieces of position information of the scale 106 read by the lower level control units 102a and 102b at the same time can be obtained.

[0141] The host controller 104 calculates the difference between the two pieces of position information, thereby enabling the above-mentioned measurements to be performed with high accuracy for the transfer modules 101a and 101b.

[0142] [Second embodiment] A manufacturing system 800 according to a second embodiment of the present invention will be described with reference to FIG. An article manufacturing system 800 includes a carriage transport system 1 according to the first or second embodiment and process devices 810 and 811, and the carriage transport system 1 transports a workpiece 801 between the process devices 810 and 811. Here, the article is, for example, a toner cartridge for an inkjet printer or a copy machine, a part for a camera, a semiconductor product, etc. The number of process devices 810 and 811 is not limited to this.

[0143] A method for manufacturing an article using the manufacturing system 800 will be described. The upper control unit 104 simultaneously transmits a group transport command to the multiple lower control units 102 at the same time, and the lower control units 102 receive the group transport command. In response to this, the lower control unit 102 applies a drive command previously received from the upper control unit 104 to the cart 105 that is in or has entered the transport module it is responsible for, and transports the cart 105 toward first and second process devices 810 and 811. A workpiece 801 is held on the cart 105, and the process devices 810 and 811 to which the cart 105 has been transported perform a predetermined process on the workpiece 801.

[0144] For example, if the article to be manufactured is a toner cartridge for an inkjet printer, the work 801 is a cartridge for containing toner powder. Then, the process equipment 810 performs a process of putting toner powder for color ink into the work 801, and the process equipment 811 performs a process of putting toner powder for black ink into the work 801. Finally, an ink cartridge product is manufactured as the article 802.

[0145] In this manner, the article manufacturing system of this embodiment can manufacture articles with the advantages of the conveying systems of the first and second embodiments, resulting in improved article manufacturing efficiency and ultimately reduced manufacturing costs. [Explanation of symbols]

[0146] 1 Cart transport system 100 Transport Path 101 Transport module 102 Lower control section ((first) control section) 104 Upper control unit (second control unit) 105 Trolley 106 Process equipment group 108 Process Control Section

Claims

1. a transport path consisting of at least two transport modules; A cart that moves along the transport path; a control unit provided in each of the two transport modules and configured to drive the carriage in response to a drive command; a sensor provided in each of the two transport modules; A transfer system, wherein the drive command is corrected based on a distance between sensors provided in each of the two transfer modules.

2. 2. The transport system according to claim 1, wherein the distance between the sensors is a value determined by the sensors provided at each of the sensors.

3. The carriage includes a permanent magnet; the transport module includes a coil group; 3. The transport system according to claim 1, wherein the control unit controls an amount of current flowing through the coil group.

4. A second control unit that controls the control unit is further provided.

4. The transport system according to claim 1, wherein the drive command is transmitted from the second control unit to the control unit.

5. 5. The transfer system according to claim 1, wherein the drive command includes a position represented by a coordinate system set for each of the two transfer modules.

6. a first drive command is used to move the carriage along the first transport module; moving the carriage across the first transport module and the second transport module in response to the first drive command and the second drive command; a method for transporting a carriage, the method comprising: moving the carriage along the second transport module in response to the second drive command, the method comprising: a second drive command corrected based on a distance between a first sensor provided in the first transport module and a second sensor provided in the second transport module,

7. 7. The method according to claim 6, wherein the distance is determined using the first sensor and the second sensor.

8. A method for manufacturing an article using the conveyance system according to claim 1 and at least one process device, transporting the carriage to the process device by the transport system; and a step of manufacturing the article by the process device performing a predetermined process on the workpiece on the cart.

Images