阅读说明：本技术 一种面向轮轨力测试的柔性电子装置及其制备方法 (Flexible electronic device for wheel-rail force test and preparation method thereof ) 是由 董文涛 黄永安 刘林芽 王晓明 姚道金 于 2020-01-02 设计创作，主要内容包括：本发明公开了一种轮轨力在线监测的柔性多功能电子装置,涉及轨道交通轮轨关系与柔性电子领域,包括温度感知、动态应变感知和压电振动感知功能模块,均集成到同一柔性基板上,安装在车轮辐板曲面上,与之保持共形接触,利用辐板动态应变和振动信息计算轮轨之间的作用力,实现了高速列车轮轨接触状态(温度、动态应变和振动信息)的实时监测,发明了微机电加工和激光剥离技术制备一种柔性多功能电子装置,为柔性电子技术在轮轨关系中的监测应用提供技术保障。(The invention discloses a flexible multifunctional electronic device for on-line monitoring of wheel-rail force, which relates to the field of wheel-rail relationship and flexible electronics of rail transit, and comprises temperature sensing, dynamic strain sensing and piezoelectric vibration sensing functional modules which are integrated on the same flexible substrate, are arranged on a wheel web curved surface and keep conformal contact with the wheel web curved surface, and calculate acting force between wheel rails by using web dynamic strain and vibration information to realize real-time monitoring of the contact state (temperature, dynamic strain and vibration information) of the wheel rails of a high-speed train.)

1. The utility model provides a flexible multi-functional electronic device towards wheel rail power on-line monitoring, a serial communication port, including temperature perception, dynamic strain perception and piezoelectricity vibration perception function module, all function module all integrate to same flexible base plate, it is installed on the curved surface structure of wheel radials, good flexibility can guarantee that flexible multi-functional electronic device keeps conformal contact with the curved surface structure of wheel radials, realized the real-time supervision to high-speed train wheel rail contact state relation (temperature, dynamic strain and vibration information), guarantee high-speed train and orbital structure health monitoring and safe travel.

2. The method for manufacturing a flexible multifunctional electronic device for on-line wheel-rail force monitoring according to claim 1, it is characterized in that a layer of sacrificial layer material is prepared on an inorganic polycrystalline silicon substrate, the operations of thin film deposition, patterning, lead wire and packaging of the flexible multifunctional electronic device (temperature, strain gauge and piezoelectric) are completed by a micro electro mechanical system processing technology, the flexible multifunctional electronic device is successfully peeled from the silicon-based substrate by adjusting the technological parameters of the laser peeling technology, the preparation work of the flexible multifunctional electronic device facing the wheel-rail relationship monitoring is completed, the conformal contact between the flexible multifunctional electronic device and a wheel-rail radial plate curved surface structure is ensured, the technological integration between a rigid inorganic functional material and the flexible substrate is solved, the health monitoring problem of a complex curved surface structure is broken through, and the main technological steps of the flexible multifunctional electronic device are as follows:

(1) preparing a polycrystalline silicon substrate, and finishing the cleaning work of the wafer through a standard wafer cleaning process;

(2) preparing a sacrificial layer film by spin coating, and curing the polymer film by heating;

(3) preparing a metal strain gauge and a temperature film by film deposition;

(4) spin-coating photoresist on the metal surface, performing photoetching exposure through a mask plate, and completing patterning of bottom electrodes of the metal strain, temperature film and piezoelectric film by combining a wet etching process;

(5) the method comprises the steps of preparing a die of the piezoelectric ceramic thin film PZT by using a positive glue inversion process, and completing patterning work of the piezoelectric ceramic thin film PZT by using a glue removing process through magnetron sputtering of the piezoelectric ceramic thin film PZT;

(6) sputtering a top electrode of the piezoelectric ceramic thin film PZT, and then completing patterning of the top electrode of the piezoelectric ceramic thin film PZT through photoetching exposure;

(7) sputtering a metal lead film, completing patterning of the metal lead by utilizing photoetching exposure and wet etching processes, and leading out electric signals of functional units such as piezoelectricity, strain and heat sensitivity;

(8) the encapsulation of the flexible multifunctional electronic device is realized by organic polymers;

(9) adjusting technological parameters of laser stripping to realize separation of the flexible multifunctional electronic device from the polycrystalline silicon substrate;

(10) and transferring the successfully peeled flexible multifunctional electronic device onto a flexible substrate to complete the preparation of the flexible multifunctional electronic device.

3. The flexible multifunctional electronic device for on-line wheel-rail force monitoring as claimed in claim 1, wherein the flexible multifunctional electronic device has ultra-thin and ultra-light properties, and keeps conformal contact with a curved surface of a wheel spoke plate, so that dynamic performance of train operation is not affected, and accuracy and stability of signal acquisition are improved.

4. The flexible multifunctional electronic device for on-line wheel-rail force monitoring as claimed in claims 1 and 2, wherein the flexible multifunctional electronic device is attached to the curved surface of the wheel spoke plate to collect vibration, dynamic strain and temperature signals in the wheel-rail action process in real time, so that on-line structural health monitoring of the wheels of the high-speed train is realized.

5. A flexible multifunctional electronic device for on-line wheel-rail force monitoring according to claims 1 to 4, which is embedded in a wheel of a rail transit vehicle, and provides a sensing device for on-line wheel-rail force acquisition and measurement.

Technical Field

The invention relates to the field of rail transit wheel-rail relation and flexible electronics, in particular to a wheel-rail force test-oriented flexible electronic device and a preparation method thereof.

Background

The wheel-rail relationship determines the comfort, safety and environmental friendliness of high-speed train running to a great extent, the irregularity characteristic of the rail and the periodic vibration of the train are directly reflected in the wheel-rail action, so that the action between the wheel rails is also dynamically changed, therefore, the monitoring of the action state of the wheel rails is always an important subject in the running of the train, the structure health monitoring technology of the wheel rails has wide application prospect, particularly the online health monitoring technology, and provides technical support for the safe and reliable running of the high-speed train.

At present, the detection technology of the wheel-rail action relationship mainly comprises vehicle-mounted monitoring and roadside monitoring, the wheel-rail relationship monitoring based on the roadside monitoring is deeply explored by Lexuan Yan of the university of east China traffic, and the like, a sensor is installed on a rail structure, and the structural health state of a wheel is identified and evaluated through a test of response to the rail structure.

In practical application, the detection brief description of the wheel-rail action relationship of the high-speed train plays a crucial role in the safe running of the train, the flexible electronic technology is embedded in the curved surfaces in the wheel and rail structures and seamlessly integrated with the curved surfaces, the dynamic performance of the train and the rail is not affected, the real-time monitoring of the wheel-rail action relationship is realized, the intelligent detection level of the rail transit industry is improved, the rapid development of the rail transit industry is accelerated, and the application of the flexible electronic technology in the major industry is realized.

Disclosure of Invention

Aiming at the defects or improvement requirements of the prior art, a first purpose of the invention is to provide a flexible multifunctional electronic device for testing wheel-rail force, which comprises temperature sensing, dynamic strain sensing and piezoelectric vibration sensing functional modules, wherein all the functional modules are integrated on the same flexible substrate and are arranged on a curved surface structure of a wheel spoke plate, the good flexibility performance ensures that the flexible multifunctional electronic device keeps conformal contact with the curved surface structure of the wheel spoke plate, the dynamic strain, temperature and vibration information of the wheel spoke plate is acquired in real time, the real-time monitoring of the wheel-rail contact state relationship (temperature, dynamic strain and vibration information) of a high-speed train is indirectly realized, the acting force between wheel rails is obtained through calculation, and the structural health monitoring and safe driving of the high-speed train and the rails are ensured.

In view of the above drawbacks or needs for improvement in the prior art, a second object of the present invention is to provide a method for manufacturing a flexible multifunctional electronic device, in which a sacrificial layer is formed on an inorganic polysilicon-based substrate, and the processing operations such as thin film deposition, patterning, wire bonding, and encapsulation of the flexible multifunctional electronic device (temperature, strain gauge, piezoelectric, etc.) are performed by a mems processing technique, and the flexible multifunctional electronic device is successfully peeled from the silicon-based substrate by adjusting the processing parameters of a laser peeling technique, thereby completing the manufacturing of the flexible multifunctional electronic device facing the wheel-rail relationship monitoring, and the method includes the following main processing steps:

(1) the cleaning work of the polycrystalline silicon substrate is completed through a standard cleaning process;

(2) preparing a sacrificial layer film by spin coating, and curing the polymer film by heating;

(3) preparing a metal strain gauge and a temperature film by film deposition;

(4) spin-coating photoresist on the metal surface, performing photoetching exposure through a mask plate, and completing patterning of bottom electrodes of the metal strain, temperature film and piezoelectric film by combining a wet etching process;

(5) preparing a die of a piezoelectric ceramic film (lead zirconate titanate, PZT) by using a positive glue inversion process, and completing patterning work of the PZT by using a glue removal process through magnetron sputtering the PZT;

(6) sputtering a top electrode of the piezoelectric ceramic thin film PZT, and then completing patterning of the top electrode of the piezoelectric ceramic thin film PZT through photoetching exposure;

(7) sputtering a metal lead film, completing patterning of the metal lead by utilizing photoetching exposure and wet etching processes, and leading out electric signals of functional units such as piezoelectricity, strain and heat sensitivity;

(8) the encapsulation of the flexible multifunctional electronic device is realized by organic polymers;

(9) adjusting technological parameters of laser stripping to realize separation of the flexible multifunctional electronic device from the polycrystalline silicon substrate;

(10) and transferring the successfully peeled flexible multifunctional device onto a flexible substrate to complete the preparation of the flexible multifunctional electronic device.

Furthermore, the flexible multifunctional electronic device for testing the wheel rail force and the preparation method thereof are characterized in that a temperature sensor, a strain gauge and a piezoelectric sensing module are integrated at the same time, the flexible multifunctional electronic device is attached to the curved surface of a wheel spoke plate structure and used for recording wheel rail action information of a high-speed train in the running process in real time, collecting wheel vibration, temperature, dynamic strain and other information and calculating acting force (transverse force and vertical force) between wheel rails, providing technical and information support for analyzing the healthy state of wheels and a track structure of the high-speed train, realizing real-time evaluation of the running state of the high-speed train and improving the safe running and comfortable level of the high-speed train, and having great engineering application prospect and research value.

Generally, compared with the prior art, the wheel-rail force test-oriented flexible multifunctional electronic device has the advantages that the flexible multifunctional electronic device is of a multi-layer ultrathin film structure (the thickness of a flexible substrate is 5 micrometers, and the thickness of a functional film is smaller than 1 micrometer), has good flexibility, integrates functional modules such as temperature, piezoelectric vibration test and dynamic strain, records the temperature of a wheel web of a high-speed train in the motion process, and vibration and dynamic strain signals of a wheel rail, is used for calculating the acting force between the wheel rails, and provides data support for the wheel action in the safe running of the high-speed train. The ultrathin flexible multifunctional electronic device is arranged on the surface of the curved surface structure of the wheel spoke plate, the stress condition of the train in the running process is recorded in real time, the influence of the environment, the wheel rail effect and the like on the safe and stable running of the train is analyzed, and the structural health detection level and the safety performance of the high-speed train are improved.

The flexible multifunctional device is used for online testing of the wheel-rail relationship of a high-speed train, achieves online testing of wheel-rail force, integrates temperature, vibration and dynamic strain sensing functions, collects action signals of wheels and rails in the running process of the wheel-rail in real time and influences of external environment on the wheels (rails) of the train, and provides technical support for optimizing the structures and installation modes of the wheels and the rails.

In summary, according to the flexible multifunctional electronic device for wheel-rail force testing and the manufacturing method thereof, the process integration between the rigid inorganic functional material and the flexible substrate is solved by adopting micro-electro-mechanical processing and laser transfer stripping, the manufacturing work of the flexible multifunctional electronic device is completed, the structural health monitoring of the complex curved surface part is realized, and the industrial application of the flexible electronic technology in rail transit is promoted. The flexible multifunctional electronic device is arranged on the curved surface of the wheel web, ensures that the flexible multifunctional electronic device is in conformal contact with the curved surface of the wheel web of the wheel rail vehicle, integrates temperature, vibration and dynamic strain functional modules, records the stress, temperature distribution and vibration modal signals of wheels in the wheel rail action process in the running process of a train in real time, analyzes the influence of environment, wheel rail action and the like on the safe and stable running of the train, and improves the structural health detection level and the safety performance of the high-speed train.

Drawings

Fig. 1 is a schematic diagram of online monitoring of wheel-rail force based on a flexible multifunctional electronic device, wherein the upper left diagram is a schematic diagram of a wheel-rail contact state, and the flexible multifunctional electronic device is mounted on a curved surface structure surface of a wheel spoke plate; the upper right drawing is a functional structure layout drawing of the flexible multifunctional electronic device; the lower diagram is a test schematic of vibration, temperature and dynamic strain in a flexible multifunctional electronic device.

Fig. 2 is a process flow of manufacturing the flexible multifunctional electronic device.

Fig. 3 is a complex variant of a flexible multi-function electronic device, wherein fig. a is a view of the flexible multi-function electronic device being able to be folded into a complex form; figure b shows the flexible multifunctional electronic device in conformal contact with the conical surface.

Fig. 4 is a flowchart of a wheel-rail action state monitoring implementation based on the flexible multifunctional electronic device.

The symbolic meanings in the figures are as follows:

11-sleeper support; 12-a track; 13-wheel web camber; 14-a flexible substrate; 15-a piezoelectric functional unit; 16-a temperature sensing unit; 17-strain sensing unit.

21-piezoelectric element metal electrodes; 22-piezoelectric functional film; 23-a metal strain gauge; 24-a thermistor thin film; 25-metal lead.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Referring to fig. 1, the flexible multifunctional electronic device is attached to the curved surface of the wheel web structure and used for online monitoring of wheel-rail acting force, wherein the upper left drawing provides a detection device for an action relationship between a curved surface structure 13 of a wheel web of a high-speed train and a rail 12 (supported by a sleeper 11 below the rail), a temperature sensing module 16, a dynamic strain sensing module 17 and a piezoelectric vibration sensing module 15 are integrated, and all functional modules are integrated on the same flexible substrate 14. The flexible multifunctional electronic device has good flexibility, can keep conformal contact with a complex curved surface of a wheel spoke plate structure, and improves the signal precision and reliability in the real-time recording wheel-rail effect. The functional structure corresponding to the flexible multifunctional electronic device is shown in the upper right diagram of fig. 1, and comprises a piezoelectric vibration testing module, a dynamic strain testing module of a metal strain gauge and a temperature testing module of a metal thermistor. The piezoelectric vibration testing module is prepared by adopting a piezoelectric inorganic material (piezoelectric ceramics PZT) 22, and a layer of metal electrode 21 is respectively prepared on the upper surface and the lower surface of the piezoelectric ceramics and used for leading out the potential change of the upper layer and the lower layer of a piezoelectric film caused by vibration, thereby realizing leading out the piezoelectric voltage change; the dynamic strain change in the wheel-track relation effect is obtained by testing a full-bridge circuit constructed by the metal strain gauges 23, and the full-bridge circuit constructed by the 4 metal strain gauges 23 improves the precision and the sensitivity of the dynamic strain test; the temperature changes of the wheel-rail effect and the external environment are measured by the thermistor film 24, and the temperature change conditions of the external environment and the wheel-rail effect are revealed. The designed sensing function signals are led out through the metal lead 25, are conveniently connected with an additional acquisition circuit and are used for acquiring signals sensed by the multifunctional device, and continuous online monitoring of wheel-rail acting force is realized. The lower diagram in fig. 1 is a test schematic of vibration, temperature and dynamic strain in a flexible multifunctional electronic device. And the piezoelectric functional unit is utilized to realize vibration test in the wheel-rail action, and the vibration mode condition caused by the wheel-rail action is obtained according to the real-time change of the output voltage of the piezoelectric film. The output resistance of the metal strain gauge can be dynamically changed under the action of the wheel track (causing dynamic strain change), and a method for testing dynamic strain in the action of the wheel track is provided. The output resistance of the thermistor film changes along with the temperature changes of the wheel track and the external environment, and the temperature testing technology is provided by utilizing the thermosensitive effect of metal.

In order to solve the process integration problem of the electronic device from the hard silicon-based substrate to the flexible substrate, a micro-electro-mechanical processing and laser transfer stripping technology is proposed to complete the processing and preparation of the flexible multifunctional electronic device, and a specific processing process flow is shown in fig. 2 and mainly comprises the following steps:

(1) preparing a polycrystalline silicon substrate, ultrasonically cleaning the polycrystalline silicon substrate in acetone, ethanol and deionized water solution, and blow-drying the surface of the polycrystalline silicon substrate by using nitrogen;

(2) spin-coating a polyimide solution on the surface of the polycrystalline silicon substrate, and heating the polyimide solution by a hot plate and an oven to realize the solidification of the polymer film, thereby completing the preparation of the sacrificial layer film;

(3) preparing a metal film on the polymer film by deposition, wherein the metal film is used as a bottom electrode of a metal strain gauge, a temperature sensor and a piezoelectric ceramic film;

(4) spin-coating photoresist on the metal surface, heating the photoresist, carrying out photoetching exposure through a mask plate, transferring the pattern in the mask plate to a photoresist film, showing the pattern in a developing solution, and completing patterning of a metal strain, temperature film and piezoelectric film bottom layer electrode by utilizing a wet etching process;

(5) the method comprises the steps of completing the difference of a die of the piezoelectric ceramic thin film PZT by utilizing a positive photoresist inversion process and combining a photoetching exposure technology, and completing the patterning of the piezoelectric ceramic thin film PZT by utilizing an acetone photoresist stripping process through magnetron sputtering of the piezoelectric ceramic thin film PZT;

(6) sputtering a piezoelectric ceramic film PZT, and then completing patterning of a top electrode of the piezoelectric ceramic film PZT by photoetching exposure and combining a wet etching technology;

(7) sputtering a metal lead film, completing patterning of the metal lead by utilizing photoetching exposure and wet etching processes, and leading out electric signals of functional units such as piezoelectricity, strain and heat sensitivity;

(8) packaging of the flexible multifunctional device is realized through organic polymer, and patterning of the polymer film is completed by adopting oxygen reactive ion etching;

(9) adjusting technological parameters of laser stripping to realize sintering of the polyimide film, and separating the flexible multifunctional electronic device from the polycrystalline silicon substrate by utilizing the inconsistency of thermal expansion coefficients of different films;

(10) and transferring the successfully peeled flexible multifunctional electronic device onto a flexible substrate to complete the preparation of the flexible multifunctional electronic device.

To further illustrate the flexible properties and conformal contact ability of the flexible multifunctional electronic device of the present invention with a complex curved surface, fig. 3 shows a schematic diagram of a complex deformation of the flexible multifunctional electronic device, fig. 3a is a schematic diagram of a flexible multifunctional electronic device capable of being folded into a complex form and undergoing a large bending deformation; fig. 3b shows that the flexible multifunctional electronic device and the conical curved surface keep conformal contact, which indicates that the flexible multifunctional electronic device and the complex curved surface structure keep conformal contact, actively adapt to the wheel spoke plate curved surface structure, and expand the application scenarios of the flexible electronic device.

In order to realize that the flexible multifunctional electronic device is attached to the surface of the curved surface structure of the wheel spoke plate and realize the structural health monitoring in the running process of the high-speed train, referring to fig. 4, the wheel-rail action state monitoring based on the flexible multifunctional electronic device comprises the following steps:

(1) the flexible multifunctional electronic device is attached to the surface of the curved surface structure of the wheel spoke plate of the train, so that the precision and the reliability of signal acquisition are improved;

(2) under different external loads and wheel rotating speeds, the flexible multifunctional electronic device collects vibration, dynamic strain and temperature output values of the wheel pair in the action process to complete calibration work of the flexible multifunctional electronic device;

(3) the flexible multifunctional electronic device is used for acquiring the wheel-rail action state information (vibration, dynamic strain and temperature) of the high-speed train in the running process, so that the on-line monitoring of the wheel-rail action force is realized;

(4) analyzing whether abnormal conditions exist in the wheel-rail action process or not according to vibration, dynamic strain and temperature information acquired by the flexible multifunctional electronic device under different running speed conditions;

(5) the online health monitoring of the wheel-rail action relation is realized by using vibration, dynamic strain and temperature information acquired by the flexible multifunctional electronic device, and the running level of the wheel-rail is improved;

(6) the method has the advantages that the characteristic data acquired by the flexible multifunctional electronic device are used for calculating the acting force between the wheel rails on line, the structural damage conditions of the wheels and the rails in the wheel rail acting process are identified by an intelligent method, and the service life of the wheels and the maintenance management level of the rails are improved.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.