CN112522675B

CN112522675B - Feedback control system and method based on heating surface pit test

Info

Publication number: CN112522675B
Application number: CN202011462675.XA
Authority: CN
Inventors: 朱佳敏; 高中赫; 陈思侃; 赵跃; 张智巍; 吴蔚; 刘杰; 丁逸珺; 常同旭
Original assignee: SHANGHAI SUPERCONDUCTOR TECHNOLOGY CO LTD
Current assignee: SHANGHAI SUPERCONDUCTOR TECHNOLOGY CO LTD
Priority date: 2020-12-14
Filing date: 2020-12-14
Publication date: 2021-07-30
Anticipated expiration: 2040-12-14
Also published as: CN112522675A

Abstract

The invention provides a feedback control system and a method based on a pit test of a heating surface, which comprises the following steps: the range finder, the driving mechanism and the heating device; the range finder is in driving connection with the driving mechanism; the heating device is arranged in the detection range of the distance meter; the range finder detects the radians of a plurality of step surfaces on the heating device and the width and depth of gaps between every two step surfaces; and the feedback control system controls the temperature of the coating film according to the detection result and judges whether the heating device needs to be maintained or not. The invention can timely judge whether the heating device needs to be maintained according to the detected gap width, the detected gap depth and the detected radian of the step surface, thereby improving the film coating quality of the superconducting strip. The detected gap width, gap depth and step surface radian can also be used as input parameters for temperature control, so that the control on the coating of the strip material is more accurate and effective.

Description

Feedback control system and method based on heating surface pit test

Technical Field

The invention relates to the field of superconducting materials, in particular to a feedback control system and method based on a heating surface pit test.

Background

The description herein refers to PLD plating of a REBCO film but is not limited to REBCO, a superconducting material or PLD, a method.

In the coating process of various vacuum coating processes, in order to ensure the quality of a film on a substrate, the preparation of a plurality of films needs to heat the coated substrate, and strict requirements are imposed on the temperature deviation range of the substrate in the coating process. Therefore, the heating system is an essential part of the coating apparatus. For a continuous flexible substrate strip with a narrow and long width, a roll-to-roll structure which reciprocates circularly is often adopted in the coating process to increase the coating area and improve the coating efficiency. Although the heating systems have different structures, sizes, geometric shapes and the like in different equipment, the roll-to-roll tape-moving structure of the strip of the approximately two-dimensional flexible substrate requires that the area of the heating surface uniform-temperature area adopted by the heating system is large enough to match the increased coating area, so that the temperature of the strip in the coating process is kept unchanged. In summary, in order to ensure the coating quality of the reel-to-reel continuous strip, the heating system needs to ensure the temperature of the strip to be uniform on a large-area heating surface. On the other hand, large-scale industrial production requires a high tape speed of the flexible substrate to meet the demand for high throughput thereof. The size limitation of the heating plates and the high speed of the tape transport result in a short heating time of the flexible substrate tape, and how to raise the temperature of the tape to the target temperature in a short time is a new demand for the heating system.

The deposition temperature is one of the most critical parameters in the superconducting layer process. The temperature zone for the growth of the ReBCO film is very narrow and is generally only 20 ℃. It is often not convenient to measure the temperature of the substrate accurately. The reason is that there is often a significant difference between the measured temperature and the actual temperature. The thermocouple is used to test the temperature of the substrate, the stability of the test depends on the stable contact between the two, and even if the contact is ideal, the bottom surface and the surface of the substrate still have a temperature gradient, which is the source of the difference.

The heating system has reached thermal equilibrium and if the base strip placed therein is static at this time, the base strip can be considered as a point in a thermal environment. At this point, the substrate is likely to reach a thermal equilibrium state due to the longer heat exchange. This differential relationship is therefore stable and it is relatively easy to determine the relative optimum deposition temperature.

Unlike static processes, in a dynamic tape-walking system, each point in the baseband experiences many different positions along the entire path. Due to the thermal gradients in the heating system, the temperature fluctuates at various points along the entire baseband path. The base band passes through the path at a certain speed and passes through different temperature areas, so that continuous heat absorption and heat release processes can be realized, and the temperature cannot be fixed all the time. If the base band is controlled to be at the optimum temperature during coating, the optimal situation is that the temperature gradient in the whole path taken by the base band is smaller, and the better. However, the larger the area of the film to be coated, the better the large area, and the larger the area, the larger the temperature gradient is easily caused, which creates a contradiction with the ideal temperature control situation.

Two of these problems are very troublesome: 1. and (3) obtaining the temperature distribution of the position of the strip of the coating area through a series of temperature tests. 2. How to obtain the temperature distribution of the strip passing through the coating area again.

The first problem is difficult because of the following two reasons: 1. the thermocouple cannot be directly arranged in the coating area, so that coating can be interfered, and plasma plume generated during coating can also interfere with testing. 2. The testing of optical temperature such as laser light cannot be used in the cavity, because the coated dust covers the optical device.

The second problem is even more difficult, and the temperature of the surface of the base tape depends on the temperature itself at the time of entering the coating area and the process of absorbing and releasing heat in the coating area. The temperature of each strip at the moment it enters the coating zone is in turn determined by the process of conductive heating with the heating plate and by the process of radiant heating between the reflecting walls.

The thermocouple group has a high probability of failure in measurement due to the complicated heating structure and environment, which is usually interfered by water cooling, plasma plume, roller defect, and the like. For example, the results of testing a superconducting tape show that the critical current on one side of the tape decays even to 0A due to a low temperature. The temperature drops to 50-100 ℃ below the lower limit of the window when the film is coated according to the crystal structure of the film, but the temperature fluctuation range is only 5-10 ℃ according to the test data of the thermocouple group.

The coated strip can be wound on a heating plate or a heating roller in a reciprocating manner in multiple ways, and in order to prevent the strips between the ways from slipping and then contacting with each other mechanically to cause damage, the multiple reciprocating strip ways can be arranged at intervals.

The heating roller or plate is typically made of a super-hard alloy material that conducts heat well, such as Inconel (r) alloy. However, the gaps between the multiple reciprocating strips on the heating roller or plate form natural pits in the heating plate or roller in the face of the long-term bombardment of the PLD plume.

The formation of such a pit is disadvantageous for the plating film.

1. The coating material can also coat a film on the surface of the heating device, the film on the surface of the heating device is uneven due to the existence of pits, and once the coating material is close to and contacted with the strip of the road in the process of running, the coating material is mutually in mechanical contact to cause damage. This occurs for a short period of time in the case of thicker built-up film layers on heated rollers and heated plates. The long-term occurrence of the pits can cause the serious unevenness of the step surface.

2. Thus, each strip will adhere to a step surface of the heating plate or heating roller, and the step surface is often less than the width of the strip, even less than half the width of the strip. This leads to a certain change in the conduction of the heating temperature of the strip.

3. The step surface and the edge of the gap can be arc-shaped frequently, and if the radian is large, the conduction of the heating temperature of the strip material can be changed to a certain extent.

Disclosure of Invention

In view of the shortcomings in the prior art, it is an object of the present invention to provide a feedback control system and method based on a heated pit test.

According to the invention, the feedback control system based on the heated surface pit test comprises: the range finder comprises a range finder 1, a driving mechanism 2 and a heating device;

the distance measuring instrument 1 is connected to the driving mechanism 2 in a driving way;

the heating device is arranged in the detection range of the distance measuring instrument 1;

the range finder 1 detects the radians of a plurality of step surfaces on the heating device and the width and depth of gaps between every two step surfaces;

and the feedback control system judges whether the heating device needs to be maintained or not according to the detection result.

Preferably, the parameter of the heat conduction temperature gradient influencing the width direction of the strip is obtained as a temperature control parameter when the strip is coated according to the radian of each step surface of the heating device.

Preferably, the method for determining whether the heating device needs to be maintained according to the detection result includes:

and determining whether to replace the heater according to the width and the depth of the gap and the radian of each step surface of the heating device.

and performing a difference method according to the detected profile and the profile detected after the last heating device stripping maintenance, estimating the thickness of a coating film layer on the heating device according to the difference value, and judging whether the heating device needs to be stripped according to the thickness of the coating film layer.

and judging whether the heating device needs to be subjected to film removal or not according to the detected gap depth.

Preferably, the driving mechanism 2 comprises a guide rail with a driving motor, and the distance measuring instrument 1 is mounted on the driving mechanism 2 through a distance measuring instrument bracket 7.

Preferably, the heating means comprise a heating drum 3 or a heating plate 4;

the heating roller 3 or the heating plate 4 is mounted on a positioning bracket.

Preferably, the drive mechanism 2 and the heating device are mounted on a base 5, respectively.

The invention provides a feedback control method based on a heating surface pit test, which comprises the following steps:

detecting the radians of a plurality of step surfaces on the heating device, and the width and depth of gaps between every two step surfaces;

according to the radian of each step surface of the heating device, obtaining a heat conduction temperature gradient which influences the width direction of the strip as a temperature control parameter when the strip is coated;

determining whether to replace the heater according to the width and the depth of the gap and the radian of each step surface of the heating device;

according to the contour obtained by detection and the contour detected after the last heating device is subjected to film removal maintenance, making a difference method, estimating the thickness of a film coating film layer on the heating device according to the difference value, and judging whether the heating device needs to be subjected to film removal or not according to the thickness of the film coating film layer;

Compared with the prior art, the invention has the following beneficial effects:

the invention can timely judge whether the heating device needs to be maintained or replaced according to the detected gap width, the detected gap depth and the radian of each step surface of the heater, thereby improving the film coating quality of the superconducting strip.

According to the radian of each channel of the detected heating device, the parameter of the heat conduction temperature gradient influencing the width direction of the strip is obtained and used as a temperature control parameter when the strip is coated, so that the coating temperature can be more accurately controlled.

And performing a difference method according to the detected profile and the detected profile after the last heating device film removal maintenance, estimating the thickness of a film coating film layer on the heating device according to the difference value, and judging whether the heating device needs to be subjected to film removal or not according to the thickness of the film coating film layer, so that the film coating quality of the superconducting tape is improved.

And judging whether the heating device needs to be subjected to film removal according to the detected gap depth, and if the film layer at the groove is protruded, the strip is easy to scratch with the film layer, and the turned edge is damaged.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a schematic diagram of a first embodiment of a feedback control system based on a heated pit test;

FIG. 2 is a schematic diagram of a second embodiment of a feedback control system based on a heated pit test;

FIG. 3 is an enlarged view of a portion of the first embodiment;

FIG. 4 is an enlarged fragmentary view of the second embodiment;

FIG. 5 is a waveform diagram of a range finder detection;

FIG. 6 is a schematic cross-sectional view of a pit.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.

Example 1

As shown in fig. 1 and fig. 3, the feedback control system based on the heated pit test provided in this embodiment includes: a distance meter 1, a driving mechanism 2 and a heating roller 3.

The range finder 1 is in driving connection with the driving mechanism 2, the heating roller 3 is installed on the roller positioning support 8 and is arranged in the detection range of the range finder 1, and the range finder 1 detects the radian of a plurality of step surfaces on the heating roller 3 and the width and depth of a gap between every two step surfaces, as shown in fig. 5. And the feedback control system controls the temperature of the coating film according to the detection result and judges whether the heating roller 3 needs to be maintained or not.

Example 2

As shown in fig. 2 and 4, the feedback control system based on the heated pit test provided in this embodiment includes: range finder 1, drive mechanism 2 and hot plate 4.

1 drive connection of distancer is on actuating mechanism 2, and hot plate 4 is installed on hot plate locating support 9 to set up in distancer 1's detection range, the radian of a plurality of step faces and the gap width between two liang of step faces, the gap degree of depth on distancer 1 detection hot plate 4, as shown in fig. 5, fig. 6. And the feedback control system judges whether the heating plate 4 needs to be maintained or not according to the detection result.

In the two embodiments, the method for controlling the temperature of the coating film according to the detection result and determining whether the heating device needs to be maintained includes:

1. and obtaining the temperature gradient influencing the width direction of the strip according to the comparison between the current detection result and the last detection result. The higher the temperature of the coating film is, the faster the change speed of the width, the depth and the radian of the step surface of the gap is, so that the temperature gradient in the width direction of the strip can be judged according to the change degree of certain detection data of different detection points, and the overlarge temperature change is avoided.

2. And judging whether the heating device needs to be replaced or not according to the detected gap depth.

3. And according to the gap width obtained by detection, performing a difference method on the current gap width and the gap width detected last time, estimating the thickness of a coating film layer on the heating device according to the difference value of the gap widths, and judging whether the heating device needs to be subjected to film removal treatment according to the thickness of the coating film layer.

In the above two embodiments, the distance measuring device 1 may adopt a laser distance measuring device and the like, the driving mechanism 2 includes a guide rail with a driving motor, and the distance measuring device 1 is installed on the driving mechanism 2 through the distance measuring device support 7. The driving mechanism 2 and the heating device are respectively installed on the base 5.

The method for controlling the temperature of the coating film comprises the following steps:

a gray level acquisition step: the method comprises the steps of acquiring a gray image of the side of a film layer of a strip to be detected in the film coating process in real time, dividing each strip to be detected into a plurality of parts along the length direction, and obtaining a plurality of corresponding gray values.

And (3) thickness difference calculation: and comparing the gray values of different parts to obtain the gray difference. The higher the temperature of the plating film, the whiter the gray image, i.e., the larger the gray value.

A feedback control step: and (3) controlling the temperature of the coating film according to the gray scale difference, the gap width and the step surface radian in a feedback manner, so that the gray scale difference is controlled within a preset range.

Specifically, the method for controlling the temperature of the coating film according to the detection result and judging whether the heating device needs to be maintained comprises the following steps:

and according to the radian of each step surface of the heating device, obtaining a heat conduction temperature gradient which influences the width direction of the strip as a temperature control parameter when the strip is coated. Generally, the higher the coating temperature, the faster the radian change of the step surface. Therefore, the coating temperature of the collection points can be known by collecting the radian values of the multiple step surfaces, so that the temperature control is assisted.

According to the width and the depth of the gap and the radian of each step surface of the heating device, in order to avoid the breakage of the heating device, the heating device needs to be replaced when the depth exceeds a preset value, and in addition, when the width of the step surface is less than the preset value and the radian is greater than the preset value, the coating film is influenced due to insufficient contact with the strip, so that the replacement is also needed.

According to the detected depth of the gap, the thickness of the film layer plated on the surface of the heating device can be estimated. Or according to the difference method between the detected outline and the detected outline after the last heating device film removal maintenance, estimating the thickness of the film coating film layer on the heating device according to the difference value, and judging whether the heating device needs to be subjected to film removal treatment according to the thickness of the film coating film layer.

The invention also provides a feedback control method based on the pit test of the heating surface, which comprises the following steps:

Those skilled in the art will appreciate that, in addition to implementing the system and its various devices, modules, units provided by the present invention as pure computer readable program code, the system and its various devices, modules, units provided by the present invention can be fully implemented by logically programming method steps in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, embedded microcontrollers and the like. Therefore, the system and various devices, modules and units thereof provided by the invention can be regarded as a hardware component, and the devices, modules and units included in the system for realizing various functions can also be regarded as structures in the hardware component; means, modules, units for performing the various functions may also be regarded as structures within both software modules and hardware components for performing the method.

In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.

Claims

1. A feedback control system based on a heated surface dimple test, comprising: the distance measuring device comprises a distance measuring instrument (1), a driving mechanism (2) and a heating device;

the distance measuring instrument (1) is in driving connection with the driving mechanism (2);

the heating device is arranged in the detection range of the distance meter (1);

the range finder (1) detects the radians of a plurality of step surfaces on the heating device and the width and depth of gaps between every two step surfaces;

the feedback control system judges whether the heating device needs to be maintained or not according to the detection result;

according to the radian of each step surface of the heating device, obtaining a heat conduction temperature gradient influencing the width direction of the strip as a temperature control parameter when the strip is coated;

the method for judging whether the heating device needs to be maintained or not according to the detection result comprises the following steps:

determining whether to replace the heating device according to the width and the depth of the gap and the radian of each step surface of the heating device;

or according to the difference method between the detected outline and the detected outline after the last heating device stripping maintenance, estimating the thickness of the coating film layer on the heating device according to the difference value, and judging whether the heating device needs to be stripped according to the thickness of the coating film layer;

or judging whether the heating device needs to be subjected to film removal or not according to the detected gap depth;

the driving mechanism (2) comprises a guide rail with a driving motor, and the distance measuring instrument (1) is installed on the driving mechanism (2) through a distance measuring instrument support (7);

the heating device comprises a heating roller (3) or a heating plate (4);

the heating roller (3) or the heating plate (4) is arranged on the positioning bracket;

the driving mechanism (2) and the heating device are respectively arranged on the base (5).

2. A feedback control method based on a heated pit test, characterized in that, the feedback control system based on a heated pit test according to claim 1:

3. The feedback control method based on the heated pit test as set forth in claim 2, wherein the method for determining whether the heating device needs to be maintained according to the detection result comprises: