Online fault detection method for unmanned aerial vehicle hydraulic pump under complex working conditions

Abstract

The invention provides an on-line fault detection method for an unmanned aerial vehicle hydraulic pump under a complex working condition, and the method comprises the specific steps: determining the working rotation speed and load change of the hydraulic pump according to the complex condition of the unmanned aerial vehicle hydraulic pump; a frequency characteristic value is obtained by comparing the working rotating speed of the hydraulic pump; respectively comparing vibration signals of an oil distribution disc and a swash plate in the hydraulic pump and the hydraulic pump to be detected to obtain vibration power spectrograms corresponding to the oil distribution disc and the swash plate, and then obtaining energy values at frequency multiplication values corresponding to the frequency characteristic values in the respective vibration power spectrograms; obtaining a fault detection index value according to the energy values at the frequency multiplication values of the oil distribution disc and the swash plate in the hydraulic pump to be detected; and respectively comparing the fault detection index values of the oil distribution disc and the swash plate in the hydraulic pump to be detected with the fault threshold values to obtain corresponding fault results. By considering the operation condition of the unmanned aerial vehicle hydraulic pump and establishing the fault detection index, online fault state management of the oil distribution disc and the swash plate in the unmanned aerial vehicle hydraulic pump can be realized.

Description

Technical Field

[0001] The present invention relates to the field of UAV hydraulic pump fault detection, and in particular to an online fault detection method for a UAV hydraulic pump under complex working conditions. Background Art

[0002] In the hydraulic pump of UAV, the oil distribution plate and the swash plate are the core components. Since the working environment of the oil distribution plate and the swash plate in the hydraulic pump of UAV is mainly affected by two factors, load and speed, the operating conditions are complex, and there are mainly three working conditions, including the working condition 1 where the speed of the hydraulic pump is constant and the load is constant, the working condition 2 where the speed of the hydraulic pump is constant and the load changes continuously, and the working condition 3 where the speed of the hydraulic pump changes continuously and the load changes continuously.

[0003] The hydraulic pump of the UAV needs to operate reliably and stably for a long time under the above working conditions. The existing fault detection methods for the hydraulic pump of the UAV have large computational complexity, poor real-time performance, and low decision-making accuracy. Although some fault diagnosis methods may perform well in specific situations, their generalization ability and adaptability under the complex working conditions of the UAV still need to be improved, especially when considering the complex working conditions during the flight of the UAV. The efficient and accurate online real-time fault detection method for the hydraulic pump is not yet mature, which makes it difficult to meet the real-time monitoring needs of the hydraulic pump during the flight of the UAV and effectively prevent major faults.

[0004] Therefore, the present invention proposes an online fault detection method for UAV hydraulic pumps under complex working conditions, thereby solving the technical problem that the oil distribution plate and inclined plate of the UAV hydraulic pump lack an effective online real-time fault detection method and it is difficult to implement maintenance according to the situation. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides an online fault detection method for a UAV hydraulic pump under complex working conditions. By considering the complex working conditions of the UAV hydraulic pump and based on the energy value at the frequency multiple corresponding to the frequency characteristic value obtained from the vibration power spectrum of the UAV hydraulic pump, the fault detection index and fault threshold of the oil distribution plate and the swash plate in the UAV hydraulic pump are established, and the fault information of the oil distribution plate and the swash plate in the UAV hydraulic pump is obtained. By comparing with the fault threshold, the corresponding fault result is obtained, thereby realizing online refined fault status management of the oil distribution plate and the swash plate in the UAV hydraulic pump and realizing airborne online real-time detection.

[0006] The present invention provides an online fault detection method for a hydraulic pump of a UAV under complex working conditions, and the specific implementation steps are as follows:

[0007] S1. According to the complex working conditions of the UAV hydraulic pump, determine the working speed and load change of the hydraulic pump, and install the vibration acceleration sensor on the side of the oil distribution plate and the inclined plate in the comparison hydraulic pump and the hydraulic pump to be tested.

[0008] S2. According to the working speed of the comparison hydraulic pump, the frequency characteristic values ​​of the oil distribution plate and the swash plate in the comparison hydraulic pump are obtained.

[0009] S3. Compare the vibration signals of the oil distribution plate and the swash plate in the hydraulic pump during any period of stable operation acquired in step S1 to obtain a vibration power spectrum of the oil distribution plate and the swash plate, and then obtain the energy value at the frequency multiple value corresponding to the frequency characteristic value obtained in step S2 in the vibration power spectrum.

[0010] S4. Obtain a vibration power spectrum of the oil distribution plate and the swash plate according to the vibration signals of the oil distribution plate and the swash plate in the hydraulic pump to be tested during any period of stable operation acquired in step S1, and then obtain the energy value and the total energy value at the frequency multiple value corresponding to the frequency characteristic value obtained in step S2 in the vibration power spectrum.

[0011] S5. Obtain the fault detection index of the oil distribution plate and the swash plate in the hydraulic pump to be tested according to the energy value at the frequency multiple value of the oil distribution plate and the swash plate in the hydraulic pump to be tested obtained in step S4, and obtain the fault detection index value of the oil distribution plate and the swash plate in the hydraulic pump to be tested in step S5.

[0012] S6. According to the structural characteristics, materials, processes and use requirements of the oil distribution plate and the swash plate in the hydraulic pump to be tested, the fault threshold value Y1 of the abnormal vibration index T1 of the hydraulic pump to be tested, the fault threshold value Y2 of the detection index T2 of the simultaneous failure of the oil distribution plate and the swash plate in the hydraulic pump to be tested, and the main detection index T2 of the failure of the swash plate in the hydraulic pump to be tested are obtained respectively. 3-1 Failure threshold Y 3-1 , Auxiliary indicators for detecting failure of the swash plate in the hydraulic pump to be tested T 3-2 Failure threshold Y 3-2 , the main indicator T for detecting the failure of the oil distribution plate in the hydraulic pump to be tested 4-1 Failure threshold Y 4-1 and the auxiliary indicator T for detecting the failure of the oil distribution plate in the hydraulic pump to be tested 4-2 Failure threshold Y 4-2 .

[0013] S7, comparing the fault detection index values ​​of the oil distribution plate and the swash plate in the hydraulic pump to be tested obtained in step S5 with the fault thresholds obtained in step S6 respectively to obtain corresponding fault results.

[0014] Preferably, the frequency characteristic values ​​of the hydraulic pump include a fundamental frequency value, a double frequency value, a triple frequency value, a quadruple frequency value, a quintuple frequency value and a sextuple frequency value.

[0015] Preferably, the expression of the fundamental frequency value is: fundamental frequency value = hydraulic pump operating speed × number of plungers; the expression of the double frequency value is: double frequency value = 2 × fundamental frequency value; the expression of the triple frequency value is: triple frequency value = 3 × fundamental frequency value; the expression of the quadruple frequency value is: quadruple frequency value = 4 × fundamental frequency value; the expression of the quintuple frequency value is: quintuple frequency value = 5 × fundamental frequency value; the expression of the sextuple frequency value is: sextuple frequency value = 6 × fundamental frequency value.

[0016] Preferably, in step S3, the abscissa of the vibration power spectrum graph is frequency, and the ordinate of the vibration power spectrum graph is amplitude.

[0017] Preferably, the step S3 specifically includes the following sub-steps:

[0018] S31. According to the vibration power spectrum of the oil distribution plate and the swash plate, the energy of each frequency component of the vibration power spectrum is calculated. The specific expression is:

[0019] E i =V i 2

[0020] Where: E i Represents the energy value of frequency i in the vibration power spectrum, V i Represents the amplitude at frequency i in the vibration power spectrum;

[0021] S32, according to the energy distribution of the frequency components in the vibration power spectrum, obtain the frequency characteristic value obtained in step S2 corresponding to the energy concentration, and obtain the energy value at the frequency multiple value corresponding to the frequency characteristic value in the hydraulic pump, and the expression of the energy value is:

[0022]

[0023] Where: EA j It represents the energy value at the jth frequency of the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump, f j Indicates the j-frequency value of the hydraulic pump, AV ji It represents the comparison of the amplitude at frequency i near the j-fold frequency of the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump.

[0024] Preferably, in step S32, the frequency characteristic value obtained at step S2 includes a double frequency value, a triple frequency value and a quadruple frequency value.

[0025] Preferably, the step S4 specifically includes the following sub-steps:

[0026] S41. According to the vibration power spectrum of the oil distribution plate and the swash plate, the energy of each frequency component of the vibration power spectrum is calculated. The specific expression is:

[0027] E i =V i 2

[0028] Where: E i Represents the energy value of frequency i in the vibration power spectrum, V i Represents the amplitude at frequency i in the vibration power spectrum;

[0029] S42, according to the energy distribution of the frequency components in the vibration power spectrum, obtain the frequency characteristic value obtained in step S2 at the energy concentration point, and obtain the energy value at the frequency multiple value corresponding to the frequency characteristic value in the hydraulic pump to be tested, and the expression of the energy value is:

[0030]

[0031] Where: EB j represents the energy value at the j-fold frequency of the vibration power spectrum of the oil distribution plate and the side surface of the inclined plate in the hydraulic pump to be tested, f j Indicates the j-frequency value in the hydraulic pump to be tested, BV ji It represents the amplitude at frequency i near the j-fold frequency of the power spectrum of the vibration of the oil distribution plate and the side surface of the inclined plate in the hydraulic pump to be tested;

[0032] S43. According to the energy value obtained in step S42, the expression of the total energy of the vibration power spectrum of the oil distribution plate and the swash plate in the hydraulic pump to be tested is obtained as follows:

[0033] EB T =EB1+EB2+EB3+EB4+EB5+EB6.

[0034] Preferably, in step S4, the frequency characteristic values ​​obtained in step S2 include a fundamental frequency, a double frequency value, a triple frequency value, a quadruple frequency value, a quintuple frequency value and a sextuple frequency value.

[0035] Preferably, in step S5, the specific implementation process of determining the fault detection index is:

[0036] S51, the expression of the vibration abnormality index T1 of the oil distribution plate and the swash plate in the hydraulic pump to be tested is:

[0037]

[0038] S52. When the percentage of the quadruple frequency value, the quintuple frequency value and the sextuple frequency value in the total energy is greater than or equal to 60%, the oil distribution plate and the swash plate in the hydraulic pump to be tested will fail. Therefore, the expression of the detection index T2 of the simultaneous failure of the oil distribution plate and the swash plate in the hydraulic pump to be tested is obtained as follows:

[0039]

[0040] S53. When the percentage of the fundamental frequency value to the total energy is greater than or equal to 55%, and the energy values ​​of the double frequency value and the triple frequency value remain unchanged, and the energy value of the quadruple frequency value decreases, the swash plate in the hydraulic pump to be tested will fail, and thus the main detection index T of the failure of the swash plate in the hydraulic pump to be tested is obtained. 3-1 and detection auxiliary index T 3-2 The expression is:

[0041]

[0042] S54. When the percentage of the fundamental frequency value and the quadruple frequency value in the total energy is greater than or equal to 60%, and the energy values ​​of the double frequency value and the triple frequency value decrease, the oil distribution plate in the hydraulic pump to be tested will fail, so the main detection index T of the oil distribution plate failure in the hydraulic pump to be tested is obtained. 4-1 and detection auxiliary index T 4-2 The expression is:

[0043]

[0044] Preferably, the specific implementation process of step S7 is:

[0045] If the abnormal vibration index T1 of the hydraulic pump to be tested is greater than or equal to the fault threshold Y1, the vibration of the hydraulic pump to be tested is abnormal; if the abnormal vibration index T1 of the hydraulic pump to be tested is less than the fault threshold Y1, the hydraulic pump to be tested is working normally;

[0046] If the detection index T2 of the simultaneous failure of the oil distribution plate and the swash plate in the hydraulic pump to be tested is greater than or equal to the fault threshold value Y2, the oil distribution plate and the swash plate in the hydraulic pump to be tested are simultaneously failed; if the detection index T2 of the simultaneous failure of the oil distribution plate and the swash plate in the hydraulic pump to be tested is less than the fault threshold value Y2, the oil distribution plate and the swash plate in the hydraulic pump to be tested are working normally;

[0047] If the swash plate in the hydraulic pump to be tested fails, the main detection indicator T 3-1 Greater than or equal to the fault threshold Y 3-1 And the auxiliary indicator T for detecting the failure of the swash plate in the hydraulic pump to be tested 3-2 Less than the fault threshold Y 3-2 When the swash plate in the hydraulic pump to be tested fails, the main detection index T 3-1 Less than the fault threshold Y 3-1 Or the auxiliary indicator T for detecting the failure of the swash plate in the hydraulic pump to be tested 3-2 Greater than or equal to the fault threshold Y 3-2 , then the swash plate in the hydraulic pump to be tested has no fault;

[0048] If the oil distribution plate in the hydraulic pump to be tested fails, the main detection indicator T4-1 Greater than or equal to the fault threshold Y 4-1 And the auxiliary indicator T for detecting the failure of the oil distribution plate in the hydraulic pump to be tested 4-2 Less than the fault threshold Y 4-2 When the oil distribution plate in the hydraulic pump to be tested fails, the main detection indicator T 4-1 Less than the fault threshold Y 4-1 Or the auxiliary indicator T for detecting the failure of the oil distribution plate in the hydraulic pump to be tested 4-2 Greater than or equal to the fault threshold Y 4-2 , then the oil distribution plate in the hydraulic pump to be tested is not faulty.

[0049] Compared with the prior art, the present invention has the following advantages:

[0050] 1. The present invention takes into account the complex working conditions of the UAV hydraulic pump, and obtains the corresponding working speed and number of plungers of the UAV hydraulic pump for the complex working conditions in different situations. The real-time frequency characteristic information of the UAV hydraulic pump during the working process is obtained through the vibration acceleration sensor installed on the UAV hydraulic pump, and the vibration power spectrum energy of the oil distribution plate and the swash plate in the UAV hydraulic pump is calculated according to the real-time frequency characteristic information, so as to construct an accurate fault detection parameter set and the threshold value corresponding to each parameter, so as to realize real-time and rapid fault detection of the UAV hydraulic pump under complex working conditions, and finally improve the accuracy of fault detection of the oil distribution plate and the swash plate of the UAV hydraulic pump, and realize online real-time detection of the onboard UAV hydraulic pump.

[0051] 2. The present invention takes into account the different complex working conditions caused by the speed and load changes of the UAV hydraulic pump during operation, strengthens the analysis of the real-time working status of the oil distribution plate and the swash plate in the UAV hydraulic pump, and makes the detection process of the oil distribution plate and the swash plate in the UAV hydraulic pump closer to the actual operating environment of the UAV. Through real-time monitoring, the state degradation of the oil distribution plate and the swash plate in the UAV hydraulic pump can be more accurately identified, and ultimately major failures of the UAV hydraulic pump during operation can be prevented, thereby improving the overall detection efficiency. The entire detection method is simple and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a flow chart of the online fault detection method of the hydraulic pump of the unmanned aerial vehicle under complex working conditions of the present invention;

[0053] Figure 2 It is a flow chart of troubleshooting in the online fault detection method of the hydraulic pump of a UAV under complex working conditions of the present invention;

[0054] Figure 3In the online fault detection method of the hydraulic pump of the unmanned aerial vehicle under complex working conditions of the present invention, the power spectrum of the vibration signal of the oil distribution plate and the side surface of the inclined plate in the hydraulic pump is compared under the working conditions of the speed of 2400r / min and the load continuously changing;

[0055] Figure 4 This is the power spectrum of the vibration signal of the oil distribution plate and the side surface of the inclined plate in the hydraulic pump under the working conditions of 2400r / min speed and continuous load change in the online fault detection method of the hydraulic pump of the unmanned aerial vehicle under complex working conditions of the present invention. DETAILED DESCRIPTION

[0056] In order to fully describe the technical content, objectives and effects of the present invention, the following will be described in detail with reference to the accompanying drawings.

[0057] An online fault detection method for UAV hydraulic pumps under complex working conditions. This method realizes refined fault state management for fault location of the oil distribution plate and swash plate in the UAV hydraulic pump. It mainly includes three parts: establishment of fault detection indicators for complex working conditions, acquisition of fault information and output of fault detection conclusions. The main contents are: first, through the working conditions of the hydraulic pump to be tested under a certain environment, the fault detection indicators and the thresholds of the fault detection indicators related to the fault states of the oil distribution plate and swash plate in the hydraulic pump to be tested under this working condition are determined; then, the vibration signals of the oil distribution plate and swash plate in the hydraulic pump to be tested within a set time period are selected through the signals collected by the vibration acceleration sensors installed on the sides of the oil distribution plate and swash plate in the hydraulic pump to be tested, and the vibration power spectrum is calculated. For the fundamental frequency, double frequency value, triple frequency value, quadruple frequency value, quintuple frequency value and sextuple frequency value, the energy values ​​and total energy values ​​at the corresponding frequency values ​​in the vibration power spectrum are obtained to calculate the fault detection indicators; finally, according to the determined fault detection threshold, the location of the fault in the hydraulic pump to be tested is confirmed. Figure 1 As shown, the specific implementation steps are as follows:

[0058] S1. According to the complex working conditions of the UAV hydraulic pump, determine the working speed and load change of the hydraulic pump, and install the vibration acceleration sensor on the side of the oil distribution plate and the inclined plate in the comparison hydraulic pump and the hydraulic pump to be tested.

[0059] S2. According to the working speed of the hydraulic pump, the frequency characteristic values ​​of the oil distribution plate and the swash plate in the hydraulic pump are obtained. Specifically, the frequency characteristic values ​​of the hydraulic pump include the base frequency value, double frequency value, triple frequency value, quadruple frequency value, quintuple frequency value and sextuple frequency value; the expression of the base frequency value is: base frequency value = hydraulic pump working speed (r / s) × number of plungers; the expression of the double frequency value is: double frequency value = 2 × base frequency value; the expression of the triple frequency value is: triple frequency value = 3 × base frequency value; the expression of the quadruple frequency value is: quadruple frequency value = 4 × base frequency value; the expression of the quintuple frequency value is: quintuple frequency value = 5 × base frequency value; the expression of the sextuple frequency value is: sextuple frequency value = 6 × base frequency value.

[0060] S3. Compare the vibration signals of the oil distribution plate and the swash plate in the hydraulic pump during any period of stable operation acquired in step S1 to obtain a vibration power spectrum of the oil distribution plate and the swash plate, and then obtain the energy value at the frequency multiple value corresponding to the frequency characteristic value obtained in step S2 in the vibration power spectrum.

[0061] In a preferred embodiment of the present invention, the abscissa of the vibration power spectrum diagram is frequency, and the ordinate of the vibration power spectrum diagram is amplitude.

[0062] S4. Obtain a vibration power spectrum of the oil distribution plate and the swash plate according to the vibration signals of the oil distribution plate and the swash plate in the hydraulic pump to be tested during any period of stable operation acquired in step S1, and then obtain the energy value and the total energy value at the frequency multiple value corresponding to the frequency characteristic value obtained in step S2 in the vibration power spectrum.

[0063] S5. Obtain the fault detection index of the oil distribution plate and the swash plate in the hydraulic pump to be tested according to the energy value at the frequency multiple value of the oil distribution plate and the swash plate in the hydraulic pump to be tested obtained in step S4, and obtain the fault detection index value of the oil distribution plate and the swash plate in the hydraulic pump to be tested in step S5.

[0064] S6. According to the structural characteristics, materials, processes and use requirements of the oil distribution plate and the swash plate in the hydraulic pump to be tested, the fault threshold value Y1 of the abnormal vibration index T1 of the hydraulic pump to be tested, the fault threshold value Y2 of the detection index T2 of the simultaneous failure of the oil distribution plate and the swash plate in the hydraulic pump to be tested, and the main detection index T2 of the failure of the swash plate in the hydraulic pump to be tested are obtained respectively. 3-1 Failure threshold Y 3-1 , Auxiliary indicators for detecting failure of the swash plate in the hydraulic pump to be tested T 3-2 Failure threshold Y 3-2 , the main indicator T for detecting the failure of the oil distribution plate in the hydraulic pump to be tested 4-1 Failure threshold Y 4-1 and the auxiliary indicator T for detecting the failure of the oil distribution plate in the hydraulic pump to be tested 4-2 Failure threshold Y 4-2 .

[0065] S7, comparing the fault detection index values ​​of the oil distribution plate and the swash plate in the hydraulic pump to be tested obtained in step S5 with the fault thresholds obtained in step S6 respectively to obtain corresponding fault results.

[0066] Furthermore, the specific process of obtaining the energy value at the frequency multiple value corresponding to the frequency characteristic value obtained in step S2 by comparing the vibration power spectrum of the hydraulic pump is as follows:

[0067] S31. According to the vibration power spectrum of the oil distribution plate and the swash plate, the energy of each frequency component of the vibration power spectrum is calculated. The specific expression is:

[0068] E i =V i 2

[0069] Where: E i Represents the energy value of frequency i in the vibration power spectrum, V i Represents the amplitude at frequency i in the vibration power spectrum.

[0070] S32, according to the energy distribution of the frequency components in the vibration power spectrum, obtain the frequency characteristic value obtained in step S2 corresponding to the energy concentration, including the double frequency value, triple frequency value and quadruple frequency value, and obtain the energy value at the frequency characteristic value corresponding to the frequency characteristic value in the hydraulic pump, and the expression of the energy value is:

[0071]

[0072] Where: EA j It represents the energy value at the jth frequency of the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump, f j Indicates the j-frequency value of the hydraulic pump, AV ji It represents the comparison of the amplitude at frequency i near the j-fold frequency of the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump.

[0073] The specific calculation process is as follows:

[0074] Comparing the energy values ​​at the corresponding double frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump, the following are the results:

[0075]

[0076] Where: f2 represents the double frequency value of the hydraulic pump, AV 2i It represents the amplitude at frequency i near the corresponding double frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump.

[0077] Comparing the energy values ​​at the corresponding triple frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump, the following are:

[0078]

[0079] Where: f3 represents the triple frequency value of the hydraulic pump, AV 3i It represents the amplitude at frequency i near the corresponding triple frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump.

[0080] Comparing the energy values ​​at the corresponding fourth frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump, the following are the results:

[0081]

[0082] Where: f4 represents the quadruple frequency value of the hydraulic pump, AV 4i It represents the amplitude at frequency i near the corresponding fourth frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump.

[0083] Furthermore, the specific process of step S4 obtaining the energy value and the total energy value at the frequency multiple value corresponding to the frequency characteristic value obtained in step S2 in the vibration power spectrum of the hydraulic pump to be tested is as follows:

[0084] S41. According to the vibration power spectrum of the oil distribution plate and the swash plate, the energy of each frequency component of the vibration power spectrum is calculated. The specific expression is:

[0085] E i =V i 2

[0086] Where: E i Represents the energy value of frequency i in the vibration power spectrum, V i Represents the amplitude at frequency i in the vibration power spectrum.

[0087] S42, according to the energy distribution of the frequency components in the vibration power spectrum, obtain the frequency characteristic value obtained in step S2 corresponding to the energy concentration, including the fundamental frequency, double frequency value, triple frequency value, quadruple frequency value, quintuple frequency value and sextuple frequency value, and obtain the energy value at the frequency multiple value corresponding to the frequency characteristic value in the hydraulic pump to be tested, and the expression of the energy value is:

[0088]

[0089] Where: EB j represents the energy value at the j-fold frequency of the vibration power spectrum of the oil distribution plate and the side surface of the inclined plate in the hydraulic pump to be tested, f j Indicates the j-frequency value in the hydraulic pump to be tested, BV ji It represents the amplitude at frequency i near the j-fold frequency of the vibration power spectrum of the oil distribution plate and the side surface of the inclined plate in the hydraulic pump to be tested.

[0090] The specific calculation process is as follows:

[0091] The energy value at the corresponding fundamental frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump to be tested is:

[0092]

[0093] Where: f1 represents the fundamental frequency value of the hydraulic pump under test, BV 1i It represents the amplitude at frequency i near the corresponding fundamental frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the tested hydraulic pump.

[0094] The energy value at the corresponding double frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump to be tested is:

[0095]

[0096] Where: f2 represents the double frequency value of the hydraulic pump under test, BV 2i It represents the amplitude at frequency i near the double frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the tested hydraulic pump.

[0097] The energy value corresponding to the triple frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump to be tested is:

[0098]

[0099] Where: f3 represents the triple frequency value of the hydraulic pump under test, BV 3i It represents the amplitude at frequency i near the triple frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the tested hydraulic pump.

[0100] The energy value corresponding to the fourth frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump to be tested is:

[0101]

[0102] Where: f4 represents the quadruple frequency value of the hydraulic pump under test, BV 4i The amplitude at frequency i near the fourth frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the tested hydraulic pump;

[0103] The energy value corresponding to the fifth frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump to be tested is:

[0104]

[0105] Where: f5 represents the fifth frequency value of the hydraulic pump under test, BV 5i The amplitude at frequency i near the fifth frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the tested hydraulic pump.

[0106] The energy value corresponding to the sixth frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump to be tested is:

[0107]

[0108] Where: f6 represents the sixth frequency value of the hydraulic pump under test, BV 6i The amplitude at frequency i near the sixth frequency in the vibration power spectrum of the oil distribution plate and the inclined plate in the tested hydraulic pump.

[0109] S43. According to the energy value obtained in step S42, the expression of the total energy of the vibration power spectrum of the oil distribution plate and the swash plate in the hydraulic pump to be tested is obtained as follows:

[0110] EB T =EB1+EB2+EB3+EB4+EB5+EB6.

[0111] Furthermore, the specific steps of step S5 to establish the fault detection index values ​​of the oil distribution plate and the swash plate in the hydraulic pump to be tested are as follows:

[0112] S51. The expression of the vibration abnormality index T1 of the oil distribution plate and the swash plate in the hydraulic pump to be tested is:

[0113]

[0114] S52. When the percentage of the quadruple frequency value, the quintuple frequency value and the sextuple frequency value in the total energy is greater than or equal to 60%, the oil distribution plate and the swash plate in the hydraulic pump to be tested will fail. Therefore, the expression of the detection index T2 of the simultaneous failure of the oil distribution plate and the swash plate in the hydraulic pump to be tested is obtained as follows:

[0115]

[0116] S53. When the percentage of the fundamental frequency value to the total energy is greater than or equal to 55%, and the energy values ​​of the double frequency value and the triple frequency value remain unchanged, and the energy value of the quadruple frequency value decreases, the swash plate in the hydraulic pump to be tested will fail, and thus the main detection index T of the failure of the swash plate in the hydraulic pump to be tested is obtained. 3-1 and detection auxiliary index T 3-2 The expression is:

[0117]

[0118] S54. When the percentage of the fundamental frequency value and the quadruple frequency value in the total energy is greater than or equal to 60%, and the energy values ​​of the double frequency value and the triple frequency value decrease, the oil distribution plate in the hydraulic pump to be tested will fail, so the main detection index T of the oil distribution plate failure in the hydraulic pump to be tested is obtained. 4-1 and detection auxiliary index T 4-2 The expression is:

[0119]

[0120] Further, such as Figure 2 As shown, the specific implementation process of step S7 to obtain the corresponding fault result is:

[0121] If the abnormal vibration index T1 of the hydraulic pump to be tested is greater than or equal to the fault threshold Y1, the vibration of the hydraulic pump to be tested is abnormal; if the abnormal vibration index T1 of the hydraulic pump to be tested is less than the fault threshold Y1, the hydraulic pump to be tested is working normally.

[0122] If the detection index T2 of simultaneous failure of the oil distribution plate and the swash plate in the hydraulic pump to be tested is greater than or equal to the fault threshold Y2, then the oil distribution plate and the swash plate in the hydraulic pump to be tested are simultaneously failed; if the detection index T2 of simultaneous failure of the oil distribution plate and the swash plate in the hydraulic pump to be tested is less than the fault threshold Y2, then the oil distribution plate and the swash plate in the hydraulic pump to be tested are working normally.

[0123] If the swash plate in the hydraulic pump to be tested fails, the main detection indicator T 3-1 Greater than or equal to the fault threshold Y 3-1 And the auxiliary indicator T for detecting the failure of the swash plate in the hydraulic pump to be tested 3-2 Less than the fault threshold Y 3-2 When the swash plate in the hydraulic pump to be tested fails, the main detection index T 3-1 Less than the fault threshold Y 3-1 Or the auxiliary indicator T for detecting the failure of the swash plate in the hydraulic pump to be tested 3-2 Greater than or equal to the fault threshold Y 3-2 , then there is no fault in the swash plate of the hydraulic pump to be tested.

[0124] If the oil distribution plate in the hydraulic pump to be tested fails, the main detection indicator T 4-1 Greater than or equal to the fault threshold Y 4-1 And the auxiliary indicator T for detecting the failure of the oil distribution plate in the hydraulic pump to be tested 4-2 Less than the fault threshold Y 4-2 When the oil distribution plate in the hydraulic pump to be tested fails, the main detection indicator T 4-1 Less than the fault threshold Y 4-1 Or the auxiliary indicator T for detecting the failure of the oil distribution plate in the hydraulic pump to be tested 4-2 Greater than or equal to the fault threshold Y 4-2 , then the oil distribution plate in the hydraulic pump to be tested is not faulty.

[0125] The following is a further description of an online fault detection method for a hydraulic pump of a drone under complex working conditions according to the present invention in combination with an embodiment:

[0126] In this specific embodiment, the number of plungers of the drone hydraulic pump is 11, and the specific implementation steps are as follows:

[0127] S1. According to the operating conditions of the hydraulic pump of the UAV in this embodiment, it is determined that the operating speed of the hydraulic pump is 2400r / min, the load changes continuously, and the vibration acceleration sensor is installed on the sides of the oil distribution plate and the inclined plate in the comparison hydraulic pump and the hydraulic pump to be tested.

[0128] S2. According to the working speed of the comparison hydraulic pump, the base frequency value of the oil distribution plate and the inclined plate in the comparison hydraulic pump is 440Hz, represented by f1; the double frequency value is 880Hz, represented by f2; the triple frequency value is 1320Hz, represented by f3; the quadruple frequency value is 1760Hz, represented by f4; the quintuple frequency value is 2200Hz, represented by f5; the sextuple frequency value is 2640Hz, represented by f6.

[0129] S3, according to the vibration signals of the oil distribution plate and the swash plate in the hydraulic pump collected in step S1 within the first second of stable operation, the vibration power spectrum of the oil distribution plate and the swash plate is obtained, and then the energy value at the frequency multiple value corresponding to the frequency characteristic value obtained in step S2 is obtained in the vibration power spectrum. The specific calculation process is as follows:

[0130] Comparing the vibration power spectra of the oil distribution plate and the swash plate in the hydraulic pump, the energy value at the double frequency obtained in step S2 is:

[0131]

[0132] Comparing the vibration power spectra of the oil distribution plate and the swash plate in the hydraulic pump, the energy value at the triple frequency obtained in step S2 is calculated as follows:

[0133]

[0134] Comparing the vibration power spectra of the oil distribution plate and the inclined plate in the hydraulic pump, the energy value at the quadruple frequency obtained in step S2 is calculated as follows:

[0135]

[0136] S4, according to the vibration signals of the oil distribution plate and the swash plate in the hydraulic pump to be tested within the first second of stable operation acquired in step S1, the vibration power spectrum of the oil distribution plate and the swash plate is obtained, and then the energy value and the total energy value at the frequency multiple value corresponding to the frequency characteristic value obtained in step S2 are obtained in the vibration power spectrum. The specific calculation process is as follows:

[0137] The energy value at the base frequency obtained in step S2 in the vibration power spectrum of the oil distribution plate and the swash plate in the tested hydraulic pump is calculated as follows:

[0138]

[0139] The energy value at the double frequency obtained in step S2 in the vibration power spectrum of the oil distribution plate and the swash plate in the tested hydraulic pump is:

[0140]

[0141] The energy value at the triple frequency obtained in step S2 in the vibration power spectrum of the oil distribution plate and the inclined plate in the tested hydraulic pump is:

[0142]

[0143] The energy value at the fourth frequency obtained in step S2 in the vibration power spectrum of the oil distribution plate and the inclined plate in the tested hydraulic pump is:

[0144]

[0145] The energy value at the fifth frequency obtained in step S2 in the vibration power spectrum of the oil distribution plate and the inclined plate in the tested hydraulic pump is:

[0146]

[0147] The energy value at the sixth frequency obtained in step S2 in the vibration power spectrum of the oil distribution plate and the inclined plate in the tested hydraulic pump is:

[0148]

[0149] The total energy value of the vibration power spectrum of the oil distribution plate and the inclined plate in the tested hydraulic pump is: EB T =EB1+EB2+EB3+EB4+EB5+EB6=3.366938+3.412321+3.596237+2.65302+2.81

[0150] 8502+4.463709=20.310727.

[0151] S5. According to the energy values ​​at the frequency multiple values ​​of the oil distribution plate and the swash plate in the hydraulic pump to be tested obtained in step S4, the fault detection index of the oil distribution plate and the swash plate in the hydraulic pump to be tested is obtained, and the fault detection index value of the oil distribution plate and the swash plate in the hydraulic pump to be tested in step S5 is obtained. The specific calculation process is as follows:

[0152] S51. The expression of the vibration abnormality index T1 of the oil distribution plate and the swash plate in the hydraulic pump to be tested is:

[0153]

[0154] S52. The expression of the detection index T2 for simultaneous failure of the oil distribution plate and the swash plate in the hydraulic pump to be tested is:

[0155]

[0156] S53, main indicator T for detecting failure of the swash plate in the hydraulic pump to be tested 3-1 and detection auxiliary index T 3-2 The expression is:

[0157]

[0158] S54, main indicator T for detecting failure of the oil distribution plate in the hydraulic pump to be tested 4-1 and detection auxiliary index T 4-2 The expression is:

[0159]

[0160] S6. According to the structural characteristics, materials, processes and use requirements of the oil distribution plate and the swash plate in the hydraulic pump to be tested, the fault threshold value Y1=0.50 of the abnormal vibration index T1 of the hydraulic pump to be tested, the fault threshold value Y2=0.60 of the detection index T2 of the simultaneous failure of the oil distribution plate and the swash plate in the hydraulic pump to be tested, and the main detection index T2 of the failure of the swash plate in the hydraulic pump to be tested are obtained respectively. 3-1 Failure threshold Y 3-1 =0.55, auxiliary indicator T for detecting failure of the swash plate in the hydraulic pump to be tested 3-2 Failure threshold Y 3-2 =1.0, the main indicator for detecting the failure of the oil distribution plate in the hydraulic pump to be tested is T 4-1 Failure threshold Y 4-1 =0.25 and the auxiliary indicator T for detecting the failure of the oil distribution plate in the hydraulic pump to be tested 4-2 Failure threshold Y 4-2 =1.20.

[0161] S7, compare the fault detection index values ​​of the oil distribution plate and the swash plate in the hydraulic pump to be tested obtained in step S5 with the fault thresholds obtained in step S6 to obtain corresponding fault results. The specific implementation process is:

[0162] If the vibration abnormality index T1=0.51083824 of the hydraulic pump to be tested is greater than the fault threshold value Y1=0.50, the vibration of the hydraulic pump to be tested is abnormal.

[0163] If the detection index T2=0.48916176 of simultaneous failure of the oil distribution plate and the swash plate in the hydraulic pump to be tested is less than the failure threshold value Y2=0.60, the oil distribution plate and the swash plate in the hydraulic pump to be tested are working normally.

[0164] Step 4: Calculate the detection index and, there is T 4-1 ≥Y 4-1 And T 4-2 <Y 4-2 , indicating that the oil distribution plate failure occurs at this time.

[0165] If the swash plate in the hydraulic pump to be tested fails, the main detection indicator T 3-1 =0.16577142 is less than the fault threshold Y 3-1 =0.55 or the auxiliary indicator T for detecting failure of the swash plate in the hydraulic pump to be tested 3-2 =0.1690370 is greater than the fault threshold Y 3-2=1.0, the swash plate in the hydraulic pump under test has no fault.

[0166] If the oil distribution plate in the hydraulic pump to be tested fails, the main detection indicator T 4-1 =0.29639303 greater than or equal to the fault threshold Y 4-1 =0.25 and the auxiliary indicator T for the failure of the oil distribution plate in the hydraulic pump to be tested 4-2 =1.14849059 is less than the fault threshold Y 4-2 =1.20, the oil distribution plate in the hydraulic pump to be tested is faulty.

[0167] Remove the oil distribution plate in the hydraulic pump to be tested and perform fault repair.

[0168] The above embodiments are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. An online fault detection method for a hydraulic pump of a UAV under complex working conditions, characterized in that: The specific implementation steps include: S1. According to the complex working conditions of the hydraulic pump of the UAV, the working speed and load change of the hydraulic pump are determined, and the vibration acceleration sensor is installed on the sides of the oil distribution plate and the inclined plate in the comparison hydraulic pump and the hydraulic pump to be tested respectively; S2. Obtaining frequency characteristic values ​​of an oil distribution plate and a swash plate in the comparison hydraulic pump according to the working speed of the comparison hydraulic pump; S3, comparing the vibration signals of the oil distribution plate and the swash plate in the hydraulic pump during any period of stable operation acquired in step S1, obtaining a vibration power spectrum of the oil distribution plate and the swash plate, and then obtaining an energy value at a frequency multiple corresponding to the frequency characteristic value obtained in step S2 in the vibration power spectrum; S4, obtaining a vibration power spectrum of the oil distribution plate and the swash plate according to the vibration signals of the oil distribution plate and the swash plate in the hydraulic pump to be tested within any period of stable operation acquired in step S1, and then obtaining the energy value and the total energy value at the multiple frequency value corresponding to the frequency characteristic value obtained in step S2 in the vibration power spectrum; S5, obtaining a fault detection index of the oil distribution plate and the swash plate in the hydraulic pump to be tested according to the energy value at the frequency multiple value of the oil distribution plate and the swash plate in the hydraulic pump to be tested obtained in step S4, and obtaining the fault detection index value of the oil distribution plate and the swash plate in the hydraulic pump to be tested in step S5; S6. According to the structural characteristics, materials, processes and use requirements of the oil distribution plate and the swash plate in the hydraulic pump to be tested, the fault threshold value Y1 of the abnormal vibration index T1 of the hydraulic pump to be tested, the fault threshold value Y2 of the detection index T2 of the simultaneous failure of the oil distribution plate and the swash plate in the hydraulic pump to be tested, and the main detection index T2 of the failure of the swash plate in the hydraulic pump to be tested are obtained respectively. 3-1 Failure threshold Y 3-1 , Auxiliary indicators for detecting failure of the swash plate in the hydraulic pump to be tested T 3-2 Failure threshold Y 3-2 , the main indicator T for detecting the failure of the oil distribution plate in the hydraulic pump to be tested 4-1 Failure threshold Y 4-1 and the auxiliary indicator T for detecting the failure of the oil distribution plate in the hydraulic pump to be tested 4-2 Failure threshold Y 4-2 ; S7, comparing the fault detection index values ​​of the oil distribution plate and the swash plate in the hydraulic pump to be tested obtained in step S5 with the fault thresholds obtained in step S6 respectively to obtain corresponding fault results.

2. The online fault detection method for a hydraulic pump of a UAV under complex working conditions according to claim 1 is characterized in that: The frequency characteristic values ​​of the hydraulic pump include a fundamental frequency value, a double frequency value, a triple frequency value, a quadruple frequency value, a quintuple frequency value and a sextuple frequency value.

3. The online fault detection method for a hydraulic pump of a drone under complex working conditions according to claim 1 or 2 is characterized in that: The expression of the fundamental frequency value is: fundamental frequency value = hydraulic pump operating speed × number of plungers; the expression of the double frequency value is: double frequency value = 2 × fundamental frequency value; the expression of the triple frequency value is: triple frequency value = 3 × fundamental frequency value; the expression of the quadruple frequency value is: quadruple frequency value = 4 × fundamental frequency value; the expression of the quintuple frequency value is: quintuple frequency value = 5 × fundamental frequency value; the expression of the sextuple frequency value is: sextuple frequency value = 6 × fundamental frequency value.

4. The online fault detection method for a hydraulic pump of a drone under complex working conditions according to claim 1 is characterized in that: In step S3, the abscissa of the vibration power spectrum is frequency, and the ordinate of the vibration power spectrum is amplitude.

5. The online fault detection method for a hydraulic pump of a UAV under complex working conditions according to claim 1 is characterized in that: The step S3 specifically includes the following sub-steps: S31. According to the vibration power spectrum of the oil distribution plate and the swash plate, the energy of each frequency component of the vibration power spectrum is calculated. The specific expression is: E i =V i 2 Where: E i Represents the energy value of frequency i in the vibration power spectrum, V i Represents the amplitude at frequency i in the vibration power spectrum; S32, according to the energy distribution of the frequency components in the vibration power spectrum, obtain the frequency characteristic value obtained in step S2 corresponding to the energy concentration, and obtain the energy value at the frequency multiple value corresponding to the frequency characteristic value in the hydraulic pump, and the expression of the energy value is: Where: EA j It represents the energy value at the jth frequency of the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump, f j Indicates the j-frequency value of the hydraulic pump, AV ji It represents the comparison of the amplitude at frequency i near the j-fold frequency of the vibration power spectrum of the oil distribution plate and the inclined plate in the hydraulic pump.

6. The online fault detection method for a hydraulic pump of a drone under complex working conditions according to claim 1 or 5, characterized in that: In step S32, the frequency characteristic values ​​obtained in step S2 are obtained, which include double frequency value, triple frequency value and quadruple frequency value.

7. The online fault detection method for a hydraulic pump of a UAV under complex working conditions according to claim 1 is characterized in that: The step S4 specifically includes the following sub-steps: S41. According to the vibration power spectrum of the oil distribution plate and the swash plate, the energy of each frequency component of the vibration power spectrum is calculated. The specific expression is: E i =V i 2 Where: E i Represents the energy value of frequency i in the vibration power spectrum, V i Represents the amplitude at frequency i in the vibration power spectrum; S42, according to the energy distribution of the frequency components in the vibration power spectrum, obtain the frequency characteristic value obtained in step S2 at the energy concentration point, and obtain the energy value at the frequency multiple value corresponding to the frequency characteristic value in the hydraulic pump to be tested, and the expression of the energy value is: Where: EB j represents the energy value at the j-fold frequency of the vibration power spectrum of the oil distribution plate and the side surface of the inclined plate in the hydraulic pump to be tested, f j Indicates the j-frequency value in the hydraulic pump to be tested, BV ji It represents the amplitude at frequency i near the j-fold frequency of the vibration power spectrum of the oil distribution plate and the side surface of the inclined plate in the hydraulic pump to be tested; S43. According to the energy value obtained in step S42, the expression of the total energy of the vibration power spectrum of the oil distribution plate and the swash plate in the hydraulic pump to be tested is obtained as follows: EB T =EB1+EB2+EB3+EB4+EB5+EB6。 8. The online fault detection method for a hydraulic pump of a drone under complex working conditions according to claim 1 or 7, characterized in that: In step S4, the frequency characteristic values ​​obtained in step S2 include a fundamental frequency, a double frequency value, a triple frequency value, a quadruple frequency value, a quintuple frequency value and a sextuple frequency value.

9. The online fault detection method for a hydraulic pump of a drone under complex working conditions according to claim 1 is characterized in that: In step S5, the specific implementation process of determining the fault detection index is as follows: S51, the expression of the vibration abnormality index T1 of the oil distribution plate and the swash plate in the hydraulic pump to be tested is: S52. When the percentage of the quadruple frequency value, the quintuple frequency value and the sextuple frequency value in the total energy is greater than or equal to 60%, the oil distribution plate and the swash plate in the hydraulic pump to be tested will fail. Therefore, the expression of the detection index T2 of the simultaneous failure of the oil distribution plate and the swash plate in the hydraulic pump to be tested is obtained as follows: S53. When the percentage of the fundamental frequency value to the total energy is greater than or equal to 55%, and the energy values ​​of the double frequency value and the triple frequency value remain unchanged, and the energy value of the quadruple frequency value decreases, the swash plate in the hydraulic pump to be tested will fail, and thus the main detection index T of the failure of the swash plate in the hydraulic pump to be tested is obtained. 3-1 and detection auxiliary index T 3-2 The expression is: S54. When the percentage of the fundamental frequency value and the quadruple frequency value in the total energy is greater than or equal to 60%, and the energy values ​​of the double frequency value and the triple frequency value decrease, the oil distribution plate in the hydraulic pump to be tested will fail, so the main detection index T of the oil distribution plate failure in the hydraulic pump to be tested is obtained. 4-1 and detection auxiliary index T 4-2 The expression is:

10. The online fault detection method for a hydraulic pump of a drone under complex working conditions according to claim 1 is characterized in that: The specific implementation process of step S7 is: If the abnormal vibration index T1 of the hydraulic pump to be tested is greater than or equal to the fault threshold Y1, the vibration of the hydraulic pump to be tested is abnormal; if the abnormal vibration index T1 of the hydraulic pump to be tested is less than the fault threshold Y1, the hydraulic pump to be tested is working normally; If the detection index T2 of the simultaneous failure of the oil distribution plate and the swash plate in the hydraulic pump to be tested is greater than or equal to the fault threshold value Y2, the oil distribution plate and the swash plate in the hydraulic pump to be tested are simultaneously failed; if the detection index T2 of the simultaneous failure of the oil distribution plate and the swash plate in the hydraulic pump to be tested is less than the fault threshold value Y2, the oil distribution plate and the swash plate in the hydraulic pump to be tested are working normally; If the swash plate in the hydraulic pump to be tested fails, the main detection indicator T 3-1 Greater than or equal to the fault threshold Y 3-1 And the auxiliary indicator T for detecting the failure of the swash plate in the hydraulic pump to be tested 3-2 Less than the fault threshold Y 3-2 When the swash plate in the hydraulic pump to be tested fails, the main detection index T 3-1 Less than the fault threshold Y 3-1 Or the auxiliary indicator T for detecting the failure of the swash plate in the hydraulic pump to be tested 3-2 Greater than or equal to the fault threshold Y 3-2 , then the swash plate in the hydraulic pump to be tested has no fault; If the oil distribution plate in the hydraulic pump to be tested fails, the main detection indicator T 4-1 Greater than or equal to the fault threshold Y 4-1 And the auxiliary indicator T for detecting the failure of the oil distribution plate in the hydraulic pump to be tested 4-2 Less than the fault threshold Y 4-2 When the oil distribution plate in the hydraulic pump to be tested fails, the main detection indicator T 4-1 Less than the fault threshold Y 4-1 Or the auxiliary indicator T for detecting the failure of the oil distribution plate in the hydraulic pump to be tested 4-2 Greater than or equal to the fault threshold Y 4-2 , then the oil distribution plate in the hydraulic pump to be tested is not faulty.

Images