Hydraulic cylinder health state monitoring system and a method thereof

Abstract

The present invention discloses a method for predicting remaining service life of a hydraulic cylinder and a corresponding hydraulic cylinder health state monitoring system. The method comprises: acquiring a pressure parameter of the hydraulic cylinder, a working state parameter indicative of a working state of a working device, and an operating state parameter indicative of an operating state of a construction machine; calculating a hydraulic cylinder leakage parameter indicative of a leakage situation of the hydraulic cylinder based on the pressure parameter and the operating state parameter; calculating a load parameter indicative of an actual load of the hydraulic cylinder based on the working state parameter; predicting the remaining service life of the hydraulic cylinder by means of a remaining service life prediction model based on the hydraulic cylinder leakage parameter and the load parameter. Through the solution of the present invention, the remaining service life of the hydraulic cylinder can be predicted by a model that is based on a neural network algorithm, which provides strong support for the maintenance and management of the hydraulic cylinder.

Description

[0001]Description HYDRAULIC CYLINDER HEALTH STATE MONITORING SYSTEM AND A METHOD THEREOF Technical Field The present invention relates to the technical field of construction machinery detection, in particular to a method for predicting remaining service life of a hydraulic cylinder, a hydraulic cylinder health state monitoring system and a computer-readable storage medium. Background Art As a key executive component in a hydraulic transmission system, the hydraulic cylinder is widely used in various construction machines. However, due to the harsh working environment of the construction machine, the hydraulic cylinder may be worn or deformed after being used for a long time, leading to performance degradation or even failure of the hydraulic cylinder, whereby affecting the whole construction machine. Therefore, monitoring the health of the hydraulic cylinder and predicting its remaining service life is of great significance for ensuring the stable operation, improving the use efficiency, and implementing the maintenance and repair of the construction machine. Because a hydraulic cylinder often faces complex and capricious working environments, its performance attenuation and service life reduction are affected by many factors, such as workload, temperature, lubrication conditions, etc.; therefore, its accurate remaining service life is always difficult to predict. Most of the existing hydraulic cylinder health state monitoring systems can only provide the current working state information of a hydraulic cylinder, but cannot predict its accurate remaining service life. Therefore, it is necessary to further improve the existing hydraulic cylinder health state monitoring systems and remaining service life prediction methods. The present invention proposes a method for predicting remaining service life of a hydraulic cylinder and a corresponding hydraulic cylinder health state monitoring system with a view to overcoming one or more of the above technical problems and / or other technical problems in the prior art. According to one aspect of the present invention, a method for predicting remaining service life of a hydraulic cylinder is provided, the method comprising: S1: acquiring a pressure parameter of the hydraulic cylinder, a working state parameter indicative of a working state of a working device, and an operating state parameter indicative of an operating state of a construction machine; S2: calculating a hydraulic cylinder leakage parameter indicative of a leakage situation of the hydraulic cylinder based on the pressure parameter and the operating state parameter; S3: calculating a load parameter indicative of an actual load of the hydraulic cylinder based on the working state parameter; S4: predicting the remaining service life of the hydraulic cylinder by means of a remaining service life prediction model based on the hydraulic cylinder leakage parameter and the load parameter. According to a further aspect of the present invention, there is provided a hydraulic cylinder health state monitoring system. The hydraulic cylinder health state monitoring system comprises: a signal acquisition module and a calculation device, the signal acquisition module comprising a pressure sensor for detecting a pressure of the hydraulic cylinder and a working state sensor for detecting a working state parameter of a working device, wherein the calculation device is in direct or indirect signaling connection with the signal acquisition module and a control module of a construction machine to acquire a pressure parameter of the hydraulic cylinder, the working state parameter indicative of the working state of the working device, and an operating state parameter indicative of an operating state of the construction machine, wherein the calculation device is configured to implement any of the embodiments for the method for predicting remaining service life of a hydraulic cylinder. According to a still further aspect of the present invention, there is provided a computer-readable storage medium having stored thereon a computer program including an executable instructions which, when executed by a processor, implement any of the embodiments for the method for predicting remaining service life of a hydraulic cylinder. In the method for predicting remaining service life of a hydraulic cylinder and the corresponding hydraulic cylinder health state monitoring system proposed in the present invention, the working state of the hydraulic cylinder can be monitored in real time by using sensor technology, the hydraulic cylinder leakage parameter can be calculated, and thereby the remaining service life of the hydraulic cylinder can be predicted by a model that is based on neural network algorithm according to the hydraulic cylinder leakage parameter and load parameter, which provides strong support for the maintenance and management of the hydraulic cylinder. This is of great significance for ensuring the stable operation and improving the use efficiency of the construction machine. In addition, the construction machine manufacturer can obtain the health status of the hydraulic cylinder in time based on the prediction result of remaining service life, and make preparations for spare parts management and travel arrangements of after-sales service personnel in advance, so as to improve the quality and efficiency of after-sales service. Brief Description of the Drawings The above and other features and advantages of the present invention will become more apparent by describing in detail the exemplary embodiments with reference to the accompanying drawings. Fig. 1 is a flow chart of one embodiment of the method according to the present invention; Fig. 2 is a schematic diagram of an excavator with a hydraulic cylinder health state monitoring system; Fig. 3 is a schematic architecture diagram of a preferred embodiment of the hydraulic cylinder health state monitoring system according to the present invention. Detailed of the Embodiments Exemplary embodiments will now be fully described with reference to the accompanying drawings. However, exemplary embodiments can be embodied in various forms and should not be construed as limited to the embodiments set forth herein. On the contrary, they are provided to make the content of the present invention thorough and complete, and make their concepts fully conveyed to those skilled in the art. In the drawings, for the sake of clarity, the dimensions of some components may be exaggerated or distorted. In the drawings, the same reference numerals denote the same or similar structures, and therefore their detailed description will be omitted. Furthermore, the described features, structures, or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, numerous specific details are provided to help thoroughly understand embodiments of the present invention. However, it will be appreciated to those skilled in the art that the technical solution of the present invention can be implemented without one or more of the specific details, or other methods, components, etc. can be adopted. In other instances, well-known structures, methods or operations are not shown or described in detail to avoid obscuring the aspects of the present invention. Fig. 1 is a flowchart of a preferred embodiment of a method for predicting remaining service life of a hydraulic cylinder according to the present invention. As shown in the figure, the method comprises the following steps: S1: acquiring a pressure parameter of the hydraulic cylinder, a working state parameter indicative of a working state of a working device, and an operating state parameter indicative of an operating state of a construction machine; S2: calculating a hydraulic cylinder leakage parameter indicative of a leakage situation of the hydraulic cylinder based on the pressure parameter and the operating state parameter; S3: calculating a load parameter indicative of an actual load of the hydraulic cylinder based on the working state parameter; S4: predicting the remaining service life of the hydraulic cylinder by means of a remaining service life prediction model based on the hydraulic cylinder leakage parameter and the load parameter. Here, the pressure parameter, the working state parameter and the operating state parameter can be acquired concurrently or sequentially by means of respective sensors. The pressure parameter indicates the pressure level in the hydraulic cylinder. The working state parameter indicates the working state, especially the load, of the working device of the construction machine. For example, it may be an angle parameter on a boom, a bucket arm or a bucket of an excavator. The operating state parameter is, for example, an engine speed, a hydraulic pump outlet pressure, or a hydraulic oil temperature. The operating state parameter can be acquired from the existing sensors of the construction machine, because the current construction machine is usually equipped with various sensors for detecting the aforementioned parameters. The leakage of the hydraulic cylinder can be calculated from the pressure parameter and the operating state parameter of the construction machine over a period of time, so the hydraulic cylinder leakage parameter can be determined. For example, a Hilbert Transform analysis method can be used to obtain time domain characteristics of the hydraulic cylinder pressure, so as to reflect the leakage situation of the hydraulic cylinder. Hilbert Transform is a commonly used technique in signal processing, which is used to extract phase information from real signals and form complex analytical signals. It is beneficial to analyze the leakage of a hydraulic cylinder by means of Hilbert transform. For example, if the leakage of a hydraulic cylinder leads to pressure fluctuation or flow rate variation, these signals can be processed by Hilbert transform and relevant phase and frequency information can be extracted. This information is helpful in deeply understanding the dynamic characteristics of leakage, such as a leakage rate, leakage periodicity and so on. Besides Hilbert transform, many other signal processing methods, such as frequency spectrum analysis method, time domain analysis method and statistical analysis method, can be considered to analyze the leakage of a hydraulic cylinder. These methods focus on analyzing various signals (such as the pressure signal, engine speed, hydraulic pump outlet pressure and hydraulic oil temperature) acquired from the hydraulic cylinder health state monitoring system, so as to reveal the characteristics and degree of the leakage. For example, through frequency spectrum analysis of the pressure signal of the hydraulic cylinder, the energy distribution of the pressure signal at different frequencies can be extracted. Leakage usually leads to the occurrence or enhancement of some specific frequency components. By observing and analyzing the changes of these frequency components, we can judge whether there is a leakage in the hydraulic cylinder and determine the severity of the leakage. In addition, the actual load of the hydraulic cylinder can be calculated according to angle parameters and the pressure parameter in combination with the known design parameters of the excavator (such as the size, position and connections of each stressed component). Therefore, the load parameter indicative of the actual load of the hydraulic cylinder can be obtained. A neural network model can be constructed as the remaining service life prediction model on the basis of the pressure of the hydraulic cylinder and the angles of the boom, bucket arm and bucket captured by the pressure sensor and angle sensor, in combination with the operating state parameter of construction machine such as the engine speed, the outlet pressure of the hydraulic pump, and the hydraulic oil temperature. The goal of the remaining service life prediction model is to relate the load parameter, leakage parameter, etc. of the hydraulic cylinder with the life loss of the hydraulic cylinder. Based on the hydraulic cylinder leakage parameter and load parameter, the remaining service life of the hydraulic cylinder can be predicted by means of the remaining service life prediction model. The remaining service life prediction model is an artificial intelligence model based on, for example, a BP (Back Propagation) neural network algorithm. The BP neural network algorithm is a multi-layer feedforward network trained by an error back propagation algorithm. The advantage of the BP neural network algorithm lies in its powerful generalization ability, self-learning and self-adaptation ability, and it is especially suitable for solving complex internal mechanism problems. The remaining service life prediction model can be pre-trained with a large number of experimental data and historical data. In addition, the remaining service life prediction model can be constructed using other algorithms, e.g. the deep learning algorithm such as the convolutional neural network (CNN) and recurrent neural network (RNN). Here the remaining service life is successfully predicted by monitoring in real time the health of hydraulic cylinder of the construction machine and by analyzing and modeling the load of the hydraulic cylinder according to the analysis of big data and deep learning. Preferably, the predicted remaining service life is transmitted to the control device of the construction machine and displayed to the user on the display device of the construction machine. Preferably, the remaining service life of a different length is displayed in a different color. For example, the remaining service life is displayed in green when it is greater than 30 days, displayed in yellow when it is less than 30 days but more than 15 days, and displayed in red when it is less than 15 days. It can also be considered to transmit the predicted remaining service life to the mobile intelligent terminal of the construction machine user, the remote monitoring platform of the manufacturer, so that the user can know the remaining service life in time outside the construction machine. It is also preferable that the remote monitoring platform records in real time the serial numbers of construction machines having hydraulic cylinders whose remaining service life is less than a specified duration, for example, less than 30 days, and pushes the information about serial numbers and geographical positions of the construction machines to corresponding agents and / or service engineers. In this way, the agents and / or service engineers can make preparations for spare parts management and travel arrangements in advance, so as to improve the quality and efficiency of after-sales service. Fig. 2 schematically illustrates a construction machine comprising a hydraulic cylinder health state monitoring system. Here, the construction machine is an excavator. Obviously, the excavator is only exemplary, and the construction machine can also be a loader or other equipment. The excavator mainly includes a power device, an undercarriage, a working device, and a hydraulic and electrical system. The undercarriage is a supporting part of the excavator, which bears all the mass of the machine and the reaction of the working device, and meantime enables the excavator to travel for a short distance. The walking system is divided into a crawler type and a tire type by the structure. The working device is a part of the excavator that directly carries out the excavation operation. Driven by a hydraulic system, the working device can complete actions such as digging and loading. As shown in Fig. 2, the working device includes a boom 1, a bucket arm 4 and a bucket 6. The boom 1 is equipped with a boom hydraulic cylinder 2 and a boom sensor 9 for detecting a rotation angle of the boom. The bucket arm 4 is equipped with a bucket arm hydraulic cylinder 3 and a bucket arm sensor 10 for detecting an inclination angle of the bucket arm. The bucket 6 is equipped with a bucket hydraulic cylinder 5 and a bucket sensor 11 for detecting a rotation angle of the bucket. A piston of the bucket hydraulic cylinder 5 is hinged with the bucket 6 by means of a push rod 7, and hinged with the bucket arm 4 by means of a rocker 8, wherein the push rod 7 and the rocker 8 are hinged with the piston of the bucket hydraulic cylinder 5 at a same hinge point. In addition, the boom hydraulic cylinder 2, the bucket arm hydraulic cylinder 3 and the bucket hydraulic cylinder 5 are respectively equipped with a pressure sensor, not shown, for detecting the pressure parameters of the respective hydraulic cylinders. Therefore, the angle parameters are the rotation angle of the boom, the inclination angle of the bucket arm, and the rotation angle of the bucket. The pressure parameter and all angle parameters are transmitted to a cloud platform or remote server, such as the remote monitoring platform of the manufacturer, by means of a communication module of the construction machine, such as a T-box, i.e., a vehicle-mounted remote communication terminal. The remote monitoring platform is provided with a background system, which comprises a remaining service life prediction model and various algorithms. Because dimensions, connections and positions of the boom, the bucket arm and the bucket are given, the actual load of each hydraulic cylinder in a working state can be calculated based on the pressure parameter and angle parameters, and accordingly the load parameter can be obtained. Although not shown, the construction machine further comprises a rotational speed sensor for detecting the engine speed, a temperature sensor for detecting the hydraulic oil temperature, a further pressure sensor for detecting the hydraulic pump outlet pressure, and other necessary sensors. Signals of the sensors form an operating state parameter indicative of the operating state of the construction machine, which is preferably available from the control module of the construction machine by means of a CAN bus. The operating state parameter is also transmitted to, for example, the remote monitoring platform of the manufacturer by means of, for example, the communication module. Here, based on the operating state parameter and the pressure parameter over a period of time, the leakage situation of the hydraulic cylinder can be obtained and the hydraulic cylinder leakage parameter can be determined by means of, for example, a Hilbert Transform analysis method. Finally, by means of the hydraulic cylinder leakage parameter and the load parameter, the remaining service life can be predicted using the remaining service life prediction model. The predicted result can be transmitted to the construction machine by means of the communication module and displayed to the user. In an exemplary embodiment of the present application, a computer-readable storage medium is provided, on which a computer program is stored, the program comprising an executable instructions, which, when executed by, for example, a processor, can implement the steps of the method for predicting the remaining service life of a hydraulic cylinder described in any of the above embodiments. In some possible embodiments, various aspects of the present application can be embodied in the form of a program product, which contains a program code for causing the hydraulic cylinder health state monitoring system to perform the steps according to various exemplary embodiments of the present application described in the method for predicting the remaining service life of a hydraulic cylinder in the present Specification when the program product is run on a terminal device. The computer-readable storage medium may include data signals propagated in baseband or as part of a carrier wave, in which readable program codes are carried. Such propagated data signals can take many forms, including but not limited to electromagnetic signals, optical signals or any suitable combination thereof. The readable storage medium can also be any readable storage medium other than an optical disk, which can send, propagate or transmit a program for use by or in combination with an instruction execution system, apparatus or device. The program code contained in the readable storage medium can be transmitted by any suitable medium, including but not limited to wireless / wired connection, optical cable, RF, or any suitable combination thereof. Program codes for performing operations of the present application can be written in any combination of one or more programming languages, including object-oriented programming languages, such as Java, C++, and conventional procedural programming languages, such as "C" or similar programming languages. The program codes may be completely executed on a user computing device, partially executed on a user device, executed as an independent software package, partially executed on a user computing device and partially executed on a remote computing device, or completely executed on a remote computing device or a server. In the case involving a remote computing device, the remote computing device may be connected to a user computing device via any kind of networks, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (for example, through the Internet provided by an Internet service provider). The architecture diagram of a preferred embodiment of the hydraulic cylinder health state monitoring system according to the present application is now described below with reference to fig. 3. The hydraulic cylinder health state monitoring system shown in fig. 3 is just an example, and should not impose any limitation on the functions and application scopes of the embodiments of the present application. As shown in fig. 3, the hydraulic cylinder health state monitoring system includes a signal acquisition module 14, a communication module 15 and a cloud platform 12. The system is independent of the control system of the whole vehicle and can be added to the construction machine separately. Although the cloud platform 12 and the program deployed thereon are shown here, it is obvious that a local computing mode can be used instead of the cloud platform, that is, all the programs are deployed locally, e.g. on the computer of the construction machine, and relevant calculations and storage are all performed on the computer of the construction machine. However, it should be pointed out that adopting the cloud platform 12 has prominent advantages in terms of computing power, storage space, etc. The signal acquisition module 14 includes various sensors mentioned above, such as the pressure sensor and angle sensors. The communication module 15 may be, for example, a T-Box, i.e. a vehicle-mounted remote communication terminal. The communication module 15 is in signaling connection with the signal acquisition module 14. Specifically, it is in direct or indirect signaling connection with the sensors of the signal acquisition module 14 to acquire the pressure parameter and the working state parameter. The communication module is also in signaling connection with original sensors of the construction machine, such as the engine speed sensor, the hydraulic oil temperature sensor, and the hydraulic pump outlet pressure sensor. Specifically, the communication module 15 is also in signaling connection with the control device 16 of the construction machine through, for example, a CAN bus to acquire the operating state parameter, such as the engine speed, the hydraulic oil temperature and the hydraulic pump outlet pressure. The communication module 15 can acquire the operating state parameter of the construction machine and / or the calculation result of the cloud platform 12 from the control device 16 of the construction machine through the CAN bus of the construction machine. For example, the predicted remaining service life is transmitted to the construction machine, e.g. the control device 16 in the cab. A display device can be arranged in the cab, and the predicted remaining service life can be presented to the user with the help of a display interface. It is preferable to denote a different remaining service life in a different color. The communication module 15 can transmit the sensor data to the remote server or cloud platform 12 through a remote communication network, such as an Ethernet or a mobile communication network. That is, the remote server or cloud platform 12 is in indirect signaling connection with the signal acquisition module 14 and the control device 16 of the construction machine through the communication module 15, so as to obtain the pressure parameter of the hydraulic cylinder, the working state parameter indicative of the working state of the working device, and the operating state parameter indicative of the operating state of the construction machine. These sensor data are stored in a database 13 on the remote server or cloud platform 12. The database 13, the remaining service life prediction model, and other possible calculation programs are deployed on the remote server or cloud platform. The communication module 15 may be omitted, though it is shown in fig. 3. That is to say, the computer installed on the construction machine is used as a calculation device. The calculation device is in direct signaling connection with the signal acquisition module and the control device of the construction machine to acquire the pressure parameter of the hydraulic cylinder, the working state parameter indicative of the working state of the working device, and the operating state parameter indicative of the operating state of the construction machine. At this time, a trained remaining service life prediction model is deployed in the computer of the construction machine. On the whole, by acquiring various parameters and adopting the machine learning algorithm, the solution of the present application can comprehensively reflect the working state and performance change of the hydraulic cylinder, leading to a higher accuracy of prediction. In addition, the present invention can help agents and service engineers to prepare for spare parts management and maintenance in advance by recording and pushing in real time the information of remaining service life, thus reducing the waiting time for maintenance and improving the operating efficiency of the equipment. Through the description of the above embodiments, it is easy for those skilled in the art to understand that the exemplary embodiments described here can be implemented by software or by combining software with necessary hardware. Therefore, the technical solution according to the embodiments of the present application can be embodied in the form of a software product, which can be stored in a nonvolatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on the network, and includes several instructions to make a computing device (which can be a personal computer, a server, a network device, etc.) execute the method for predicting remaining service life of a hydraulic cylinder according to the embodiments of the present application. After considering the Specification and putting the disclosures here into practice, those skilled in the art will readily conceive of other embodiments of the present application. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or conventional technical means in the art that are not disclosed herein. The Specification and embodiments are to be regarded as exemplary only, with the true scope and spirit of the present application being indicated by the appended claims.

Claims

Claims 1. A method for predicting remaining service life of a hydraulic cylinder, comprising: acquiring a pressure parameter of the hydraulic cylinder, a working state parameter indicative of a working state of a working device, and an operating state parameter indicative of an operating state of a construction machine; calculating a hydraulic cylinder leakage parameter indicative of a leakage situation of the hydraulic cylinder based on the pressure parameter and the operating state parameter; calculating a load parameter indicative of an actual load of the hydraulic cylinder based on the working state parameter; predicting the remaining service life of the hydraulic cylinder by means of a remaining service life prediction model based on the hydraulic cylinder leakage parameter and the load parameter, the remaining service life prediction model is an artificial intelligence algorithm model.

2. The method according to claim 1, characterized in that the working state parameter includes angle parameters on a boom, a bucket arm and a bucket, and the operating state parameter includes an engine speed, a hydraulic pump outlet pressure and a hydraulic oil temperature.

3. The method according to claim 1 or 2, characterized in that a Hilbert transform analysis method is used to determine the corresponding hydraulic cylinder leakage parameter from the pressure parameter and operating state parameter over a period of time.

4. The method according to claim 1 or 2, characterized in that the remaining service life prediction model is an artificial intelligence algorithm model based on a BP neural network algorithm.

5. The method according to claim 1 or 2, characterized in that the predicted remaining service life is transmitted to a control device of the construction machine and displayed to a user on a display device of the construction machine.

6. The method according to claim 5, characterized in that the remaining service life of a different length is displayed in a different color.

7. The method according to claim 1 or 2, characterized in that the machine serial numbers of construction machine with hydraulic cylinders whose remaining service life is less than the specified duration, along with the corresponding geographical location information of the construction machine, are pushed to the corresponding agents and / or service engineers.

8. The method according to claim 1 or 2, characterized in that the pressure parameter, the working state parameter and the operating state parameter are acquired concurrently or sequentially.

9. A hydraulic cylinder health state monitoring system, comprising: a signal acquisition module and a calculation device, the signal acquisition module comprising a pressure sensor for detecting a pressure of the hydraulic cylinder and a working state sensor for detecting a working state parameter of a working device, wherein the calculation device is in direct or indirect signaling connection with the signal acquisition module and a control module of a construction machine to acquire a pressure parameter of the hydraulic cylinder, the working state parameter indicative of the working state of the working device, and an operating state parameter indicative of an operating state of the construction machine, wherein the calculation device is configured to implement the method for predicting remaining service life of a hydraulic cylinder according to any one of claims 1 to 8.

10. The hydraulic cylinder health state monitoring system according to claim 9, characterized by further comprising a communication module, which is in signaling connection with the signal acquisition module and the calculation device and is configured to send the pressure parameter, the working state parameter and the operating state parameter to the calculation device and transmit a calculation result of the calculation device to the construction machine.

11. The hydraulic cylinder health state monitoring system according to claim 10, characterized in that the communication module is a vehicle-mounted remote communication terminal.

12. The hydraulic cylinder health state monitoring system according to any one of claims 9 to 11, characterized in that the calculation device is a cloud platform or remote server or a computer installed on the construction machine.

13. A computer-readable storage medium having stored thereon a computer program, which includes executable instructions that, when executed by a processor, implement the method for predicting the remaining service life of a hydraulic cylinder according to any one of claims 1 to 8.

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