Operation fault monitoring method for mechanical transmission device

Abstract

The invention discloses an operation fault monitoring method for a mechanical transmission device, and the method comprises the following steps: (1), collecting a plurality of groups of operation data of a motor when the mechanical transmission device operates without faults under different working conditions, calculating the operation parameters of the motor according to the operation data, and constructing a standard operation parameter database when the mechanical transmission device operates without faults; and (2) when the mechanical transmission device runs, collecting running data of the motor, calculating running parameters of the motor according to the running data, comparing and analyzing the running parameters with standard running parameters in the database, and judging the running state of the mechanical transmission device. According to the invention, the operation state of the mechanical transmission device is monitored by using the operation data of the power motor, data acquisition by a sensor is not needed, and the operation fault can be monitored at the initial stage of the operation fault.

Description

Technical Field

[0001] The present invention relates to the field of measurement and control technology, and in particular to a method for monitoring operating failures of a mechanical transmission device. Background Art

[0002] The mechanical transmission device includes a mechanical structure and a power motor. The mechanical structure includes a gear structure, bearings, etc. The power motor refers to a three-phase permanent magnet synchronous servo motor. Operational failures of the mechanical transmission device include excessive gear clearance (excessive clearance between motor direct drive gears, etc.) and excessive bearing resistance (including entry of foreign matter, lack of oil, etc.).

[0003] At present, many mechanical equipment still rely mainly on manual regular abnormal status monitoring. However, manual monitoring often has the problem of high missed detection rate and false detection rate and low monitoring efficiency. In particular, the harsh environment in which many mechanical equipment are located also poses great challenges to manual monitoring. Automatic, effective, fast and remote monitoring of the operating status of mechanical equipment can provide a scientific basis for mechanical equipment maintenance departments, thereby shortening the maintenance cycle and reducing maintenance costs.

[0004] The existing technology generally uses sensors such as vibration sensors and temperature sensors to automatically obtain the operating data of mechanical equipment.

[0005] For example, a Chinese patent document with publication number CN111504385A discloses a multi-parameter monitoring device and method for abnormal state of mechanical equipment, wherein the device includes a data analysis and fault diagnosis server, and the data analysis and fault diagnosis server is signal-connected to multiple early warning monitoring terminals and at least two data information acquisition terminals. The data information acquisition terminal includes a microcontroller, which is respectively connected to a humidity sensor, a temperature sensor and an acceleration sensor, and the microcontroller is signal-connected to the data analysis and fault diagnosis server. The acceleration sensor and the temperature sensor are attached to the housing of the monitored mechanical equipment, and the humidity sensor is arranged in the surrounding environment space where the mechanical equipment is located.

[0006] A Chinese patent document with publication number CN116888450A discloses a method for monitoring the health status of a mechanical device or a mechanical component, which includes at least the following steps: i) obtaining actual vibration data collected in or on the mechanical device or mechanical component; and ii) determining from the actual vibration data whether there is an abnormality in the mechanical device or mechanical component and the type and / or level of the abnormality based on a health diagnosis model, wherein the health diagnosis model is constructed based on calculated vibration data calculated by a big data-corrected dynamic model of the mechanical device or mechanical component.

[0007] Since mechanical devices are generally closed, there is no extra space inside the mechanical device for installing sensors in the design. The mechanical structure itself is moving and cannot be directly installed with sensors. Therefore, vibration sensors cannot be directly installed on various mechanical structures. Generally, sensors can only be installed on the outside of the mechanical device. Therefore, when the mechanical structure fails in the early stage, external vibration sensors and other sensors cannot be directly monitored. However, this kind of failure will affect the operating parameters of the power motor, such as: increased torque, increased current, output power, and affect the motor's operating efficiency. In addition, the use of too many sensors leads to high costs for mechanical fault monitoring. Summary of the invention

[0008] The present invention provides an operation fault monitoring method for a mechanical transmission device, which uses the operation data of a power motor to monitor the operation state of the mechanical transmission device, does not require sensors to collect data, and can monitor the operation fault at the early stage of the operation fault.

[0009] The technical solution of the present invention is as follows:

[0010] A method for monitoring operation failure of a mechanical transmission device comprises the following steps:

[0011] (1) Under different working conditions, multiple groups of operating data of the motor when the mechanical transmission device is running without fault are collected, the operating parameters of the motor are calculated based on the operating data, and a standard operating parameter database of the mechanical transmission device when running without fault is constructed;

[0012] (2) When the mechanical transmission device is running, the operating data of the motor is collected, the operating parameters of the motor are calculated based on the operating data, and the operating parameters are compared and analyzed with the standard operating parameters in the database to determine the operating status of the mechanical transmission device.

[0013] If a mechanical failure occurs in the mechanical transmission device, it will directly affect the motor speed and torque current of the motor, and will indirectly affect the motor torque, output power, power loss, operating efficiency, etc. The present invention determines the operating state of the mechanical transmission device by analyzing the operating parameters of the power motor, and can detect the operating failure of the mechanical transmission device in the early stage.

[0014] The motor's operating data includes the motor's torque, current and speed. The motor's torque, current and speed can be read directly from the motor driver, or detected through external sensors. If the device has been connected to the Internet of Things, the data can be uploaded to the cloud and read from the cloud.

[0015] The operating parameters of the motor include the motor's torque, output power, power loss, and operating efficiency.

[0016] The formula for calculating the torque of the motor is:

[0017] Troq=Kt×Iq

[0018] Where: T roq is the torque; K t is the torque factor; I q is the torque current;

[0019] The formula for calculating the output power of the motor is:

[0020] Pout=Troq×Vrad

[0021] Where: P out is the output power; V rad is the motor speed;

[0022] The formula for calculating the power loss of the motor is:

[0023] P=Pcu+PFe

[0024] Where: P represents power loss; P cu is the copper loss, Pcu=Kcu×Iq, K cu is the copper loss coefficient, I q Indicates torque current; P Fe is the iron loss, P F e=K F e×Vrad,K Fe is the iron loss coefficient, V rad is the motor speed;

[0025] The formula for calculating the motor's operating efficiency is:

[0026]

[0027] Where: X out The operating efficiency of the motor.

[0028] Preferably, the operating parameters of the motor also include the motor housing temperature.

[0029] The motor casing temperature is used as a parameter to assist in judgment. When a fault is detected, the casing temperature change trend is observed to provide an indicator for relevant technical personnel.

[0030] The calculation formula for the motor housing temperature is:

[0031]

[0032] Where: T h is the case temperature, T I is the initial shell temperature, T rh is the temperature difference between the motor housing temperature and the room temperature, S h is the surface area of ​​the motor heat dissipation part, K h is the conductivity of the motor housing, C his the specific heat capacity of the shell, W h is the shell quality;

[0033]

[0034] TR cu is the winding temperature rise, W cu is the winding mass, C cu is the specific heat capacity of the winding, T is the sampling time interval;

[0035]

[0036] TR Fe is the core temperature rise, W Fe is the core mass, C Fe is the specific heat capacity of the core.

[0037] In step (1), the operating parameters of the motor are calculated according to the operating data, and a standard operating parameter database for the mechanical transmission device during trouble-free operation is constructed, including:

[0038] The average values ​​of multiple groups of motor operating parameters are taken as standard operating parameters to build a standard operating parameter database.

[0039] In step (2), the operating parameters are compared and analyzed with the standard operating parameters in the database to determine the operating state of the mechanical transmission device, including:

[0040] Compare the motor's operating parameters within a certain period of time with the standard operating parameters, and take the standard operating parameters ±n% as the allowable fluctuation range of the operating parameters. If the motor's operating parameters exceed the allowable fluctuation range, it is judged that the mechanical transmission device has a fault. n is a constant.

[0041] If any one of the multiple operating parameters exceeds the allowable fluctuation range, it is determined that the mechanical transmission device has a fault.

[0042] n is 1 to 2. The size of n is determined according to the actual situation, and is related to the diagnostic sensitivity and the specific mechanical structure.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The present invention determines the operating state of the mechanical transmission device by analyzing the operating parameters of the power motor, and can detect the operating failure of the mechanical transmission device at the early stage, and the monitoring result is relatively reliable;

[0045] The present invention does not use sensors to collect data, reduces dependence on sensors, and reduces monitoring costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1A schematic diagram of a flow chart of a method for monitoring an operation fault of a mechanical transmission device;

[0047] Figure 2 It is the flow chart of motor operating parameter calculation;

[0048] Figure 3 This is the flow chart for calculating the motor housing temperature;

[0049] Figure 4 This is a torque and current diagram of the motor when the bearing has no fault in the embodiment;

[0050] Figure 5 This is a diagram of the motor running speed when the bearing has no fault in the embodiment;

[0051] Figure 6 This is a diagram of the motor running output power when there is no bearing failure in the embodiment;

[0052] Figure 7 This is a diagram of the motor running power loss when there is no bearing failure in the embodiment;

[0053] Figure 8 This is a diagram of the motor running torque when the bearing has no fault in the embodiment;

[0054] Fig. 9 is a temperature diagram of the motor housing in the embodiment;

[0055] Fig.10 This is a torque and current diagram of the motor when the bearing fails in the embodiment;

[0056] Fig.11 This is a diagram of the motor running speed when the bearing fails in the embodiment;

[0057] Fig.12 This is a diagram of the motor running output power when the bearing fails in the embodiment;

[0058] Fig.13 This is a diagram of the motor running power loss when the bearing fails in the embodiment;

[0059] Fig.14 This is a diagram of the motor running torque when the bearing fails in the embodiment;

[0060] Fig.15 is the percentage increase in power loss of the motor with bearing fault relative to that without bearing fault in the embodiment;

[0061] Fig.16 is the percentage increase of the torque of the motor with bearing fault relative to that without bearing fault in the embodiment;

[0062] Fig.17 is the percentage reduction of the output power of the motor with bearing fault relative to that without bearing fault in the embodiment. DETAILED DESCRIPTION

[0063] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be pointed out that the embodiments described below are intended to facilitate the understanding of the present invention and do not have any limiting effect on the present invention.

[0064] If a mechanical failure occurs in the mechanical transmission device, it will affect the motor's operating speed and torque current, and will indirectly affect the motor's torque, output power, power loss, operating efficiency, casing temperature and other parameters.

[0065] When a minor fault occurs in the mechanical structure of a mechanical transmission device, the running speed and torque current of the motor will change. If the minor fault persists for a long time, the motor's torque, output power, power loss, operating efficiency, casing temperature and other parameters will become more obvious. The operating fault monitoring method of the present invention can detect minor mechanical faults in a mechanical transmission device and intervene before they become serious.

[0066] In the present invention, data is divided into two types, one is operating data; the other is operating parameters. The operating data is collected from the motor driver (torque current and speed), and the operating parameters are calculated, including torque, output power, power loss, operating efficiency, housing temperature, etc.

[0067] The process of the operation fault monitoring method of the mechanical transmission device of the present invention is as follows: Figure 1 As shown. The fault-free operation database calculates the motor torque, output power, power loss and operating efficiency under different working conditions and takes the average value. The ±1% of the average value is used as the allowable fluctuation range. If it exceeds the fluctuation range, it is determined to be faulty. As long as one of the four parameters exceeds the fluctuation range, it can be determined that there is a fault. The reason is that these four parameters can measure the different operating states of the motor. The fault of the mechanical structure may cause the motor to generate more torque or the speed to be too fast, so some abnormal conditions may occur in the four parameters. The fluctuation range of ±1% is determined according to the actual situation, which is related to the diagnostic sensitivity and the specific mechanical structure.

[0068] The motor casing temperature is a parameter used to assist in judgment and provides an indicator for relevant technicians. When a mechanical transmission device fails, relevant technicians can observe the casing temperature change trend, which is helpful for further analysis.

[0069] The operation fault monitoring method of the mechanical transmission device of the present invention includes two core parts, namely, motor operation parameter calculation and operation fault monitoring. The motor operation parameter calculation part first collects the torque current and speed of the motor operation, and then calculates the torque, output power, power loss, operation efficiency and motor housing temperature of the motor; the operation fault monitoring includes the monitoring and processing algorithm of the power motor operation data.

[0070] The motor operating parameters are read from the motor driver, detected by an external sensor, or read from the cloud (the device has been connected to the Internet of Things and the data is uploaded to the cloud). The sampling frequency is determined according to the operating conditions and is 1K (HZ) in the embodiment.

[0071] like Figure 2 and Figure 3 As shown, the monitoring and processing method of the power motor operation data includes:

[0072] (1) The copper loss of the motor is calculated based on the torque current and copper loss coefficient of the motor. The calculation formula is as follows:

[0073] Pcu=Kcu×Iq ①

[0074] Where: P cu is copper loss; K cu is the copper loss coefficient; I q Indicates torque current;

[0075] (2) Calculate the motor's iron loss based on the motor's speed and iron loss factor. The calculation formula is as follows:

[0076] P F e=K F e×Vrad ②

[0077] Where: P Fe is the iron loss; K Fe is the iron loss coefficient; V rad is the motor speed;

[0078] (3) Based on the calculated copper loss and iron loss, the winding temperature rise and core temperature rise are calculated respectively. The calculation formulas are equation ③ and equation ④:

[0079]

[0080] Where: TR cu is the winding temperature rise; W cu is the winding mass; C cu is the specific heat capacity of the winding; TR Fe is the core temperature rise; W Fe is the core mass; C Fe is the specific heat capacity of the core; T is the sampling time interval;

[0081] (4) Calculate the motor housing temperature based on the room temperature using the formula (5):

[0082]

[0083] Where: T h is the shell temperature; T I is the initial shell temperature; Trh is the temperature difference between the motor shell temperature and the room temperature; S h K is the surface area of ​​the motor heat dissipation part; h is the conductivity of the motor housing; C h W is the specific heat capacity of the shell; h is the shell quality;

[0084] (5) The torque of the motor is calculated based on the torque current and torque factor of the motor. The calculation formula is formula ⑥:

[0085] Troq=Kt×Iq ⑥

[0086] Where: T roq is the torque; K t is the torque factor; I q is the torque current;

[0087] (6) Calculate the output power of the motor based on the motor speed and torque. The calculation formula is as follows:

[0088] Pout=Troq×Vrad ⑦

[0089] Where: P out is the output power; V rad is the motor speed;

[0090] (7) The power loss of the motor is calculated based on the iron loss and copper loss. The calculation formula is as follows:

[0091] P=Pcu+P F e ⑧

[0092] Where: P represents power loss;

[0093] (8) The motor operating efficiency is calculated based on iron loss, copper loss and output power. The calculation formula is formula 9:

[0094]

[0095] Where: X out The operating efficiency of the motor.

[0096] The calculated operating efficiency, output power, power loss, and motor housing temperature are analyzed and compared with the pre-built database of the normal state of the mechanical device, and a judgment is made as to whether the mechanical structure has a fault based on the different trends of the above parameters.

[0097] Embodiment 1:

[0098] The direct drive device of the motor is a bearing, and the operating condition is to work at 1500° / S.

[0099] Under this condition, when the bearing is running without any fault, the torque current of the bearing is collected ( Figure 4 )、Speed( Figure 5 ), calculate the output power of the bearing when it is running without fault ( Figure 6 )、Power loss( Figure 7 )、Torque( Figure 8 )、Case temperature( Fig. 9 ).

[0100] The standard parameter values ​​are shown in Table 1.

[0101] Table 1 Fault-free operating parameter database

[0102] Power loss Torque Output Power Operational efficiency 6.141±1％ 0.685±1％ 17.90±1％ 74.46％±1％

[0103] During a motor operation, the bearing torque current ( Fig.10 )、Speed( Fig.11 ), calculate the output power of the bearing when it is running ( Fig.12 )、Power loss( Fig.13 )、Torque( Fig.14 )、Case temperature( Fig. 9 ).

[0104] Collect 11 sets of data, each set is collected for 1 second, and the interval between two adjacent sets is 10 minutes. Calculate the percentage increase of power loss in the 11 sets of data ( Fig.15 ), torque increase percentage ( Fig.16 ), output power reduction percentage ( Fig.17 ).

[0105] The rising trend of power loss is within the allowable range, while the percentage increase of torque and output power exceeds the normal range, so it can be determined that a fault exists.

[0106] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for monitoring operating faults of a mechanical transmission device, characterized in that: The following steps are involved: (1) Under different working conditions, multiple groups of operating data of the motor when the mechanical transmission device is running without fault are collected, the operating parameters of the motor are calculated based on the operating data, and a standard operating parameter database of the mechanical transmission device when running without fault is constructed; (2) When the mechanical transmission device is running, the operating data of the motor is collected, the operating parameters of the motor are calculated based on the operating data, and the operating parameters are compared and analyzed with the standard operating parameters in the database to determine the operating status of the mechanical transmission device.

2. The method for monitoring operating failures of a mechanical transmission device according to claim 1, characterized in that: The operating data of the motor includes the torque, current and speed of the motor; the operating parameters of the motor include the torque, output power, power loss and operating efficiency of the motor.

3. The method for monitoring the operation failure of a mechanical transmission device according to claim 2, characterized in that: The formula for calculating the torque of the motor is: Troq=Kt×Iq Where: T roq is the torque; K t is the torque factor; I q is the torque current; The formula for calculating the output power of the motor is: Pout=Troq×Vrad Where: P out is the output power; V rad is the motor speed; The formula for calculating the power loss of the motor is: P=Pcu+PFe Where: P represents power loss; P cu is the copper loss, Pcu=Kcu×Iq, K cu is the copper loss coefficient, I q Indicates torque current; P Fe is the iron loss, PFe=K F e×Vrad,K Fe is the iron loss coefficient, V rad is the motor speed; The formula for calculating the motor's operating efficiency is: Where: X out The operating efficiency of the motor.

4. The method for monitoring operating failures of a mechanical transmission device according to claim 1, characterized in that: The operating parameters of the motor also include the motor case temperature.

5. The method for monitoring operating failures of a mechanical transmission device according to claim 4, characterized in that: The calculation formula for the motor housing temperature is: Where: T h is the case temperature, T I is the initial shell temperature, T rh is the temperature difference between the motor housing temperature and the room temperature, S h is the surface area of ​​the motor heat dissipation part, K h is the conductivity of the motor housing, C h is the specific heat capacity of the shell, W h is the shell quality; TR cu is the winding temperature rise, W cu is the winding mass, C cu is the specific heat capacity of the winding, T is the sampling time interval; TR Fe is the core temperature rise, W Fe is the core mass, C Fe is the specific heat capacity of the core.

6. The method for monitoring operating failures of a mechanical transmission device according to claim 1, characterized in that: In step (1), the operating parameters of the motor are calculated according to the operating data, and a standard operating parameter database for the mechanical transmission device during trouble-free operation is constructed, including: The average values ​​of multiple groups of motor operating parameters are taken as standard operating parameters to build a standard operating parameter database.

7. The method for monitoring operating failures of a mechanical transmission device according to claim 1, characterized in that: In step (2), the operating parameters are compared and analyzed with the standard operating parameters in the database to determine the operating state of the mechanical transmission device, including: Compare the motor's operating parameters within a certain period of time with the standard operating parameters, and take the standard operating parameters ±n% as the allowable fluctuation range of the operating parameters. If the motor's operating parameters exceed the allowable fluctuation range, it is determined that the mechanical transmission device has a fault; n is a constant.

8. The method for monitoring operating failures of a mechanical transmission device according to claim 7, characterized in that: n is 1-2.

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