Table roll control device of hot rolling line

Abstract

This table roll control device of a hot rolling line controls the rotation speed of individual table rolls so that a rolled material is transported at a target speed. A table roll control device comprises: a collection unit that collects imaging data from a camera for capturing an image of a roughing mill and a table roll together with a rolled material, and registers the collected imaging data in a database; a transport speed detection unit that detects the transport speed of the rolled material from the imaging data collected by the collection unit; and a feedback control unit that performs feedback control of the rotation speed of the table roll so that the transport speed detected by the transport speed detection unit matches a target speed.

Description

Table roll control device for hot rolling lines

[0001] The present disclosure relates to a table roll control device for a hot rolling line.

[0002] This type of table roll control device is disclosed, for example, in Patent Document 1. In this device, the conveying speed of the rolled material is controlled by controlling the rotation speed of a motor that drives each of a plurality of table rolls.

[0003] However, when slippage occurs between the table roll and the rolled material, the deviation (speed difference) between the conveyance speed of the rolled material and the target speed set based on the rolling information increases. In this case, the rolled material cannot be threaded through the rolling mill at the target speed, and as a result, the rolled material cannot be rolled with good thickness control. Therefore, it is common to install strip speed meters on the upstream and downstream sides of the rolling mill and feedback-control the rotational speed of the motor so that the conveyance speed of the rolled material measured by the strip speed meters matches the target speed.

[0004] Japanese Patent Publication No. 9-99309

[0005] However, in order to ensure the measurement accuracy of the strip speed meter, it is necessary to place the strip speed meter close to the rolled material. When the strip speed meter is placed close to the rolled material, it is exposed to not only heat from the rolled material but also dust such as scale, making it prone to malfunction. In order to replace a malfunctioning strip speed meter, it is necessary to stop operation of the hot rolling line, which reduces productivity.

[0006] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a table roll control device for a hot rolling line that can control the table rolls without using a strip speed meter arranged in proximity to the rolled material.

[0007] A first aspect of the present disclosure relates to a table roll control device for a hot rolling line. The hot rolling line includes a roughing mill installed downstream of a heating furnace and table rolls installed upstream and downstream of the roughing mill to transport a rolled material to the roughing mill. The table roll control device controls the rotational speed of each table roll so that the rolled material is transported at a target speed. The table roll control device includes: a collection unit that collects image data from a camera that captures images of the roughing mill and the table roll together with the rolled material and registers the collected image data in a database; a conveying speed detection unit that detects the conveying speed of the rolled material from the image data collected by the collection unit; and a feedback control unit that feedback-controls the rotational speed of the table roll so that the conveying speed detected by the conveying speed detection unit matches the target speed.

[0008] The second aspect has the same features as the first aspect, but further includes the following: the table roll control device further includes a model generation unit that generates a model for detecting the rolled material by annotating the image data with the rolled material as the target and learning the annotated data in a library; and the conveying speed detection unit is configured to detect the rolled material in the image data using the model generated by the model generation unit and to detect the conveying speed of the detected rolled material.

[0009] A third aspect has the following features in addition to the first or second aspect. The table roll control device includes a rotational speed setting unit that sets the rotational speed of each table roll based on a target speed. The collection unit is configured to register in a database, together with the target speed and the transport speed, the steel type of the rolled material, the heating temperature and size of the rolled material extracted from the heating furnace, and the number of rolled materials that have passed through the table roll after maintenance of the table roll. The table roll control device further includes an analysis unit that uses a statistical method to analyze, from multiple elements registered in the database, factors that cause a speed difference between the target speed and the transport speed. The feedback control unit is configured to feedback control the rotational speed based on the analysis results obtained by the analysis unit.

[0010] According to the present disclosure, a configuration is adopted in which the conveying speed of the rolled material is detected using a camera positioned away from the rolled material, thereby making it possible to provide a table roll control device for a hot rolling line that can control the table rolls without using a plate speed meter positioned close to the rolled material.

[0011] It is a schematic diagram showing an example of a hot rolling line to which a table roll control device according to an embodiment is applied. It is a block diagram showing an example of the configuration of the table roll control device. It is a flowchart showing the flow of processing by the table roll control device. It is a diagram showing an example of the hardware configuration of the table roll control device.

[0012] Hereinafter, a table roll control device according to an embodiment of the present disclosure will be described with reference to the drawings. Note that elements common to the various drawings will be assigned the same reference numerals and redundant description will be omitted.

[0013] 1 is a schematic diagram showing an example of a hot rolling line 1 to which a table roll control device 100 according to an embodiment is applied. The hot rolling line 1 is equipped with, as main rolling equipment, a heating furnace 2, a roughing mill 3, a finishing mill 4, a cooling device 5, and a winder 6. Note that, between the heating furnace 2 and the roughing mill 3, a descaling device may be installed that sprays high-pressure water onto the rolled material Mr extracted from the heating furnace 2 to remove scale (oxide film) formed on the surface of the rolled material Mr.

[0014] The heating furnace 2 is configured to heat the rolled material (slab) Mr to a predetermined temperature (e.g., 1200°C) before rolling. The roughing mill 3 typically has one to three rolling stands R1 (one in the example shown in Figure 1). The roughing mill 3 is configured to perform multiple passes of rolling on the rolled material (slab) Mr extracted from the heating furnace 2 while switching the rolling direction by switching the rotation direction of table rolls 71 and 72 (described later). Each rolling stand R1 is equipped with two upper and lower work rolls 31, two upper and lower backup rolls 32, and a motor 33 for rotating the rolls. The backup rolls 32 are provided with a screw down device 34, which is configured to adjust the gap between the upper and lower work rolls 31. The rolling load of each rolling stand R1 is measured by a rolling load sensor 35.

[0015] The finishing rolling mill 4 is a tandem rolling mill equipped with multiple rolling stands F1 to F7 (seven in the example shown in FIG. 1 ) arranged side by side in the rolling direction of the rolled material Mr. Each rolling stand F1 to F7 is equipped with two upper and lower work rolls 41, two upper and lower backup rolls 42, and a motor 43 for rotating the rolls. The backup rolls 42 are provided with a screw down device 44, which is configured to adjust the gap between the upper and lower work rolls 41. The rolling load of each rolling stand F1 to F7 is measured by a rolling load sensor 45. The cooling device 5 cools the rolled material Mr by injecting water into the rolled material Mr using a cooling bank. The cooled rolled material Mr is wound into a coil by a winder 6.

[0016] Various sensors (not shown) are installed as measuring instruments at key points in the hot rolling line 1. Performance data measured by the various sensors is transmitted to the control computer 10 every moment.

[0017] The hot rolling line 1 is operated by a control system using a hierarchical computer. The computer includes a control computer 10 and a host computer 11, which are connected to each other via a network. The control computer 10 is equipped with a table roll control device 100, which will be described later. The table roll control device 100 may be provided external to the control computer 10 and connected via the network. The control computer 10 has a control controller such as a PLC (programmable logic controller). An HMI (human machine interface) device 12 is connected to the control computer 10 via the network. The HMI device 12 is configured to present data on the monitored object (rolling equipment) so that an operator (not shown) can monitor or operate (control) the monitored rolling equipment. When a rolling plan is input to the host computer 11, rolling information is sent from the host computer 11 to the control computer 10. The rolling information includes a target plate thickness, a target plate width, a target temperature, etc. The control computer 10 receives rolling information from the host computer 11, calculates setting data including setting values ​​for each rolling equipment to be controlled, and transmits the calculated design data to the hot rolling line 1, thereby controlling each rolling equipment constituting the hot rolling line 1. The setting data includes the rotational speeds of table rolls 71 and 72, which will be described later.

[0018] Meanwhile, a plurality of table rolls 71, 72, 73, and 74 for transporting the rolled material Mr to each rolling facility are installed in the hot rolling line 1. Below, a table roll control device 100 that controls the table rolls 71 and 72 installed on the upstream side (heating furnace side) and downstream side (finishing rolling mill side) of the roughing mill 3 will be described.

[0019] FIG. 2 is a block diagram showing an example configuration of the table roll control device 100. The table roll control device 100 includes a rotational speed setting unit 101, a collection unit 102, a model generation unit 103, a conveying speed detection unit 104, a feedback control unit 105, and an analysis unit 106. The camera 8 is disposed to the side of the roughing mill 3, spaced apart from the rolled material Mr being rolled by the roughing mill 3. "Spaced apart" means that the camera 8 is disposed in a location where it is not exposed to heat or scale from the rolled material Mr, and is disposed further away than the plate speed meter. The camera 8 is installed so as to capture images of the roughing mill 3 and the table rolls 71, 72 along with the conveyed rolled material Mr. The imaging range Ir of the camera 8 is a rectangle indicated by a virtual line in FIG. 2. The camera 8 may be disposed above the roughing mill 3, but considering minimizing the effects of heat and scale, it is preferable to dispose it to the side as shown in FIG. 2.

[0020] The rotational speed setting unit 101 calculates the rotational speed of each table roll 71, 72 in accordance with the target conveying speed (hereinafter referred to as "target speed") Vt of the rolled material calculated based on the rolling information, and sets it in each motor (not shown) that drives each table roll 71, 72.

[0021] The collection unit 102 collects video data (hereinafter referred to as "image data") captured by the camera 8 and registers the collected image data in a database DB. The collection unit 102 also registers in the database DB the target speed Vt calculated by the rotation speed setting unit 101 and the conveying speed Vf detected by the conveying speed detection unit 104 (described later). The collection unit 102 is configured to register in the database DB the steel type of the rolled material Mr, the heating temperature (slab temperature) and size (slab size) of the rolled material Mr extracted from the heating furnace 2, and the number of rolled materials Mr that have passed through the table rolls 71, 72 after maintenance of the table rolls 71, 72 (hereinafter referred to as the "number of passed rolled materials"). These are elements used in analysis by the analysis unit 106 (described later). The database DB may be provided external to the table roll control device 100 and connected via a network.

[0022] The model generation unit 103 annotates the image data captured in advance by the camera 8, targeting the rolled material Mr, and trains the annotated data in a library to generate a model for detecting the rolled material Mr in the image data collected by the collection unit 102. Annotation refers to illustrating the rolled material Mr to be detected in the image data, for example, as a rectangle. As the annotation method, a known method can be used, and therefore a detailed description thereof, including the software used to perform the annotation, will be omitted here. Furthermore, as the library, YOLO, which is provided as a Python library, can be used. As YOLO is a known learning algorithm, a detailed description thereof, including the training method for YOLO, will be omitted here. In this way, the model generation unit 103 is configured to create a learning model for detecting the rolled material Mr by training the annotated data in YOLO (Python library).

[0023] The conveying speed detection unit 104 detects the conveying speed Vf of the rolled material Mr from the imaging data collected by the collection unit 102. The conveying speed detection unit 104 is configured to detect the rolled material Mr in the imaging data using the model generated by the model generation unit 103, and to detect the conveying speed Vf of the detected rolled material Mr. This makes it possible to accurately detect the conveying speed Vf of the rolled material Mr from the imaging data captured by the camera 8 arranged at a distance from the rolled material Mr.

[0024] The feedback control unit 105 feedback controls the rotation speed of the table rolls 71 and 72 so that the conveying speed Vf detected by the conveying speed detection unit 104 coincides with the target speed Vt.

[0025] According to the above configuration, the conveying speed Vf of the rolled material Mr can be detected from the image data captured by the camera 8, which can be placed at a distance, without using a strip speed meter that must be placed close to the conveyed rolled material Mr. Even if a speed difference occurs between the conveying speed Vf and the target speed Vt due to the occurrence of slippage, the rotational speed of the table rolls 71, 72 can be feedback controlled so that the conveying speed Vf matches the target speed Vt, thereby making it possible to pass the rolled material Mr through the roughing mill 3 at the target speed Vt, and therefore the roughing mill 3 can roll the rolled material Mr with good thickness controllability. Moreover, because the camera 8 does not easily break down, there is no need to stop the operation of the hot rolling line, thereby improving productivity.

[0026] Incidentally, there are not just one but several factors that cause a speed difference due to slip. When performing feedback control, it is preferable to analyze the factors that cause the speed difference and use the analysis results. Furthermore, when slip occurs during multiple passes of rolling in the roughing mill 3, causing a speed difference, it may be required to perform feedback control on the material being rolled (the material in question) Mr, rather than on the next material being rolled (the next material) Mr. In this case, too, it is preferable to use the analysis results of the factors that cause the speed difference.

[0027] The analysis unit 106 included in the table roll control device 100 uses a statistical method to analyze the cause of the speed difference between the target speed Vt and the conveying speed Vf from multiple elements registered in the database DB. A known statistical algorithm can be used to analyze the cause, so a detailed description will be omitted here. The analysis results by the analysis unit 106 are registered in the database DB by the collection unit 102. The feedback control unit 105 can perform feedback control based on the analysis results.

[0028] An example of the operation of the table roll control device 100 will now be described, including the analysis by the analysis unit 106. Fig. 3 is a flowchart showing the flow of processing by the table roll control device 100.

[0029] When the rolled material Mr is detected in the image data captured by the camera 8, the collection unit 102 collects the image data (step S1). The collection unit 102 registers the collected image data in the database DB together with the steel type, slab temperature, slab size, and number of passing rolled materials included in the rolling information (step S2).

[0030] Next, it is determined whether or not the analysis results have been registered in the database DB (step S3). If the analysis results have not yet been registered, the process proceeds to step S6. On the other hand, if the analysis results have already been registered, the process proceeds to step S4.

[0031] In step S4, the collected data for the material Mr is compared with the registered analysis results to determine whether or not there is a likelihood of a speed difference occurring between the target speed Vt and the conveying speed Vf. If there is no or very little likelihood of a speed difference occurring, the process proceeds to step S6. On the other hand, if there is a likelihood of a speed difference occurring, the rotation speeds of the table rolls 71 and 72 are feedback-controlled (step S5). Then, the process proceeds to step S6.

[0032] In step S6, it is determined whether the number of unanalyzed data items stored in the database DB is greater than a reference value. The reference value is set appropriately so that analysis can be performed efficiently in relatively large units, and can be set to, for example, 40 items. If the number of unanalyzed data items is equal to or less than the reference value, data analysis by the analysis unit 106 is not performed, and the process returns to step S1. On the other hand, if the number of unanalyzed data items is greater than the reference value, the process proceeds to step S7.

[0033] In step S7, the analysis unit 106 reads the unanalyzed data from the database DB and analyzes the causes of the speed difference using statistical methods. The analysis results by the analysis unit 106 are registered in the database DB by the collection unit 102 (step S8), and are used for subsequent feedback control (step S5), making it possible to perform feedback control not only on the next material but also on the material in question. When the processing of step S8 is completed, the processing returns to step S1.

[0034] As described above, according to this embodiment, a configuration is adopted in which the conveying speed Vf of the rolled material Mr is detected using a camera 8 arranged at a distance from the rolled material Mr, so that a table roll control device 100 can be provided for a hot rolling line 1 that can control the table rolls 71, 72 without using a plate speed meter arranged in close proximity to the rolled material Mr.

[0035] FIG. 4 is a diagram showing an example of the hardware configuration of the table roll control device 100. The above-described functions of the table roll control device 100 can be realized by the processing circuit 110 shown in FIG. 4. The processing circuit 110 may be dedicated hardware 110a. The processing circuit 110 may also include a processor 110b and a memory 110c. The processing circuit 110 may be partially formed as dedicated hardware 110a and further include a processor 110b and a memory 110c. In the example shown in FIG. 4, the processing circuit 110 is partially formed as dedicated hardware 110a, and also includes a processor 110b and a memory 110c. The processing circuit 110 may be at least one dedicated hardware 110a. In this case, the processing circuit 110 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof. The processing circuit 110 may also include at least one processor 110b and at least one memory 110c. In this case, each function of the table roll control device 100 is realized by software, firmware, or a combination of software and firmware. The software and firmware are written as programs and stored in the memory 110c. The processor 110b realizes each function of the table roll control device 100 by reading and executing the programs stored in the memory 110c. The processor 110b is also called a CPU (Central Processing Unit), central processing unit, processing device, arithmetic unit, microprocessor, microcomputer, or DSP. The memory 110c corresponds to a storage device such as a non-volatile or volatile semiconductor memory, such as RAM, ROM, flash memory, EPROM, or EEPROM. The memory 110c can also serve as a database (DB). In this way, the processing circuit 110 can realize each function of the table roll control device 100 by hardware, software, firmware, or a combination of these.

[0036] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments and can be implemented in various modifications without departing from the spirit of the present disclosure. In the above embodiments, an example in which imaging is performed using one camera 8 has been described, but imaging may also be performed using two cameras. In this case, the upstream table roll 71 and roughing mill 3 can be imaged using a first camera, and the downstream table roll 72 and roughing mill 3 can be imaged using a second camera. This allows the imaging range of each camera to be narrowed, thereby improving the detection accuracy of the rolled material Mr in the imaging data and ultimately enabling the conveying speed Vf of the rolled material Mr to be detected with high accuracy, which is advantageous.

[0037] Furthermore, when the number, quantity, amount, range, etc. of each element is mentioned in the above-mentioned embodiments, the present invention is not limited to the mentioned numbers unless otherwise specified or clearly specified in principle. Furthermore, the structures, etc. described in the above-mentioned embodiments are not necessarily essential to this disclosure unless otherwise specified or clearly specified in principle.

[0038] 1...hot rolling line, 2...heating furnace, 3...roughing mill, 71, 72...table roll, 8...camera, 100...table roll control device, 101...rotational speed setting unit, 102...collection unit, DB...database, 103...model generation unit, 104...conveyance speed detection unit, 105...feedback control unit, 106...analysis unit, 110...processing circuit, Mr...rolled material, Vf...conveyance speed, Vt...target speed

Claims

1. A table roll control device for a hot rolling line, the hot rolling line comprising a roughing mill installed downstream of a heating furnace, and table rolls installed respectively upstream and downstream of the roughing mill for transporting rolled material to the roughing mill, the table roll control device controlling the rotational speed of each table roll so that the rolled material is transported at a target speed, the table roll control device comprising: a collection unit that collects image data from a camera that images the roughing mill and the table roll together with the rolled material, and registers the collected image data in a database; a transport speed detection unit that detects the transport speed of the rolled material from the image data collected by the collection unit; and a feedback control unit that feedback-controls the rotational speed of the table roll so that the transport speed detected by the transport speed detection unit matches the target speed.

2. A table roll control device for a hot rolling line as described in claim 1, further comprising a model generation unit that generates a model for detecting the rolled material by annotating the image data with the rolled material as the target and learning the annotated data in a library, and the conveying speed detection unit is configured to detect the rolled material in the image data using the model generated by the model generation unit and detect the conveying speed of the detected rolled material.

3. A table roll control device for a hot rolling line according to claim 1 or claim 2, comprising a rotational speed setting unit that sets the rotational speed of each table roll based on the target speed, wherein the collection unit is configured to register in the database the steel type of the rolled material, the heating temperature and size of the rolled material extracted from the heating furnace, and the number of rolled materials that have passed through the table roll after maintenance of the table roll, along with the target speed and the transport speed, and the table roll control device for a hot rolling line further comprises an analysis unit that uses statistical techniques to analyze factors that cause a speed difference between the target speed and the transport speed from the elements registered in the database, and the feedback control unit is configured to feedback control the rotational speed set by the rotational speed setting unit based on the analysis results obtained by the analysis unit.

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