Flexible actuator fault diagnosis method

Abstract

The invention provides a fault diagnosis method for a flexible actuator. The method comprises the following steps: adjusting the output force of an active driving mechanism based on a constructed kinematic model of the flexible actuator so as to enable the output force to be in a sine wave form; taking the magnitude of the output force of the active driving mechanism at each moment as a judgment condition, and utilizing one linear displacement sensor as a reference to calibrate other displacement sensors, so that the active driving mechanism and each linear displacement sensor are positioned on the same reference; according to the output force of the active driving mechanism, the expected displacement of the active driving mechanism is obtained; the difference between the expected displacement value of the active driving mechanism and the calibrated output displacement value of each linear displacement sensor is obtained and then is compared with a preset diagnosis coefficient, so that fault diagnosis is carried out on the active driving mechanism and each linear displacement sensor. According to the scheme, accurate diagnosis of the fault of the flexible actuator during on-orbit operation of the spacecraft can be realized.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of spacecraft attitude control, and in particular to a flexible actuator fault diagnosis method. Background Art

[0002] The traditional primary control of spacecraft platforms is limited by many factors such as actuator performance, control bandwidth, and measurement bandwidth, and further improvement of spacecraft payload pointing control performance has encountered bottlenecks. The secondary composite control method of spacecraft based on flexible actuators has the advantages of high degree of freedom, high pointing accuracy, and high structural rigidity. It will become an essential technology for high-quality control of spacecraft such as extremely high-resolution earth observation and space-based astronomical observation.

[0003] With the long-term operation of spacecraft in orbit, the performance parameters of the active link of its flexible actuator are inevitably reduced. In the process of the spacecraft's secondary compound control, the operating state of the flexible actuator is directly related to the load stability and the performance of the spacecraft's secondary compound control. Therefore, timely diagnosis and treatment of the flexible actuator's fault can provide support for the design of the spacecraft's secondary compound control parameters and achieve stable operation of the spacecraft in orbit.

[0004] Based on this, there is an urgent need to provide a flexible actuator fault diagnosis method. Summary of the invention

[0005] An embodiment of the present invention provides a flexible actuator fault diagnosis method, which can achieve accurate diagnosis of flexible actuator faults during the on-orbit operation of a spacecraft, effectively isolate the faulty actuator, and achieve stable on-orbit operation of the spacecraft.

[0006] In a first aspect, an embodiment of the present invention provides a method for diagnosing a flexible actuator fault, wherein the flexible actuator includes a passive damping mechanism, an active driving mechanism, and at least two linear displacement sensors;

[0007] Methods include:

[0008] The output force of the active driving mechanism is adjusted based on the constructed kinematic model of the flexible actuator so that the output force is in the form of a sine wave;

[0009] Taking the output force of the active drive mechanism at each moment as a determination condition, calibrate the other displacement sensors using one of the linear displacement sensors as a reference, so that the active drive mechanism and each linear displacement sensor are located at the same reference;

[0010] Obtaining a desired displacement of the active driving mechanism according to the output force of the active driving mechanism;

[0011] The expected displacement value of the active drive mechanism and the calibrated output displacement value of each linear displacement sensor are subtracted from each other and then compared with the preset diagnosis coefficients to perform fault diagnosis on the active drive mechanism and each linear displacement sensor respectively.

[0012] In a second aspect, an embodiment of the present invention further provides a flexible actuator fault diagnosis device, wherein the flexible actuator includes a passive damping mechanism, an active driving mechanism, and at least two linear displacement sensors;

[0013] The device includes:

[0014] An adjustment unit, used for adjusting the output force of the active driving mechanism based on the constructed kinematic model of the flexible actuator, so that the output force is in a sine wave form;

[0015] A calibration unit, used to calibrate other displacement sensors using one of the linear displacement sensors as a reference, taking the output force of the active drive mechanism at each moment as a determination condition, so that the active drive mechanism and each linear displacement sensor are located at the same reference;

[0016] a calculation unit, configured to obtain a desired displacement of the active drive mechanism according to an output force of the active drive mechanism;

[0017] The fault diagnosis unit is used to compare the expected displacement value of the active drive mechanism and the calibrated output displacement value of each linear displacement sensor with the preset diagnosis coefficients after making a difference between them, so as to perform fault diagnosis on the active drive mechanism and each linear displacement sensor respectively.

[0018] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, enables the computer to execute the method described in any embodiment of this specification.

[0019] On the other hand, an embodiment of the present application further provides a computer program product, which includes a computer program. A processor of a computer device reads the computer program from a computer-readable storage medium, and the processor executes the computer program, so that the computer device executes any of the methods described in the above embodiments.

[0020] On the other hand, an embodiment of the present invention further provides a computer program product, including a computer program, which implements the steps of the above-mentioned method when executed by a processor.

[0021] An embodiment of the present invention provides a flexible actuator fault diagnosis method, which first constructs a kinematic model of the flexible actuator, and adjusts the output force of the flexible actuator to a sinusoidal wave form based on the kinematic model. Then, the output force of the active drive mechanism at each moment is used as a judgment condition, and one of the linear displacement sensors is used as a benchmark to calibrate the other displacement sensors to unify the benchmarks of the active drive mechanism and each linear displacement sensor. Finally, the output displacement value of each linear displacement sensor after the unified benchmark and the expected displacement value of the active drive mechanism are subtracted from each other and compared with a preset diagnostic coefficient. The comparison results are analyzed and compared respectively to achieve accurate diagnosis of the active drive mechanism and each linear displacement sensor fault. Furthermore, based on the diagnostic result, the faulty flexible actuator can be effectively isolated to achieve stable on-orbit operation of the spacecraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 is a flow chart of a flexible actuator fault diagnosis method provided by one embodiment of the present invention;

[0024] Figure 2 is a hardware architecture diagram of a computing device provided by an embodiment of the present invention;

[0025] Figure 3 It is a structural diagram of a flexible actuator fault diagnosis device provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] Please refer to Figure 1 , an embodiment of the present invention provides a flexible actuator fault diagnosis method, the flexible actuator includes a passive damping mechanism, an active driving mechanism and at least two linear displacement sensors;

[0028] The method includes:

[0029] Step 100, adjusting the output force of the active driving mechanism based on the constructed kinematic model of the flexible actuator so that the output force is in a sinusoidal wave form;

[0030] Step 102, taking the output force of the active drive mechanism at each moment as a determination condition, using one of the linear displacement sensors as a reference to calibrate the other displacement sensors, so that the active drive mechanism and each linear displacement sensor are located at the same reference;

[0031] Step 104, obtaining a desired displacement of the active driving mechanism according to the output force of the active driving mechanism;

[0032] Step 106 , subtracting the expected displacement value of the active drive mechanism and the output displacement value of each calibrated linear displacement sensor from each other and comparing them with preset diagnostic coefficients respectively, so as to perform fault diagnosis on the active drive mechanism and each linear displacement sensor respectively.

[0033] In an embodiment of the present invention, a kinematic model of a flexible actuator is first constructed, and the output force of the flexible actuator is adjusted to a sinusoidal wave form based on the kinematic model. Then, the output force of the active drive mechanism at each moment is used as a judgment condition, and one of the linear displacement sensors is used as a benchmark to calibrate other displacement sensors to unify the benchmarks of the active drive mechanism and each linear displacement sensor. Finally, the output displacement value of each linear displacement sensor after the unified benchmark and the expected displacement value of the active drive mechanism are subtracted from each other and compared with a preset diagnostic coefficient. The comparison results are analyzed and compared respectively to achieve accurate diagnosis of faults of the active drive mechanism and each linear displacement sensor. Furthermore, based on the diagnostic results, the faulty flexible actuator can be effectively isolated to achieve stable on-orbit operation of the spacecraft.

[0034] In an embodiment of the present invention, the flexible actuator in the secondary control system includes a passive damping mechanism, an active driving mechanism and at least two linear displacement sensors installed in sequence; wherein the passive damping mechanism is used to provide passive damping force for the movement of the flexible actuator to attenuate external high-frequency disturbance force and torque, the active driving mechanism is used to output the force, and the linear displacement sensor is used to measure the translational displacement of the flexible actuator.

[0035] For step 100:

[0036] In some embodiments, the kinematic model of the flexible actuator is as follows:

[0037]

[0038]

[0039] Wherein, m is the driving load mass of the flexible actuator (for example, it can be 15 kg), c is the damping coefficient of the passive damping mechanism of the flexible actuator (for example, it can be 0.04 N / (mm / s)), k is b is the stiffness coefficient of the active drive mechanism of the flexible actuator (for example, it can be 15N / mm), x is the motion displacement of the active drive mechanism of the flexible actuator, and are the first-order derivative and second-order derivative of the motion displacement of the active drive mechanism, F is the output force of the active drive mechanism, L mi is the output displacement of the i-th linear displacement sensor, λ i is the scale factor of the i-th linear displacement sensor (for example, it may be 1 or 1.2).

[0040] In some embodiments, the output force of the active drive mechanism is in the form of:

[0041] F=Asin(2*π*f*t)

[0042] Wherein, A is the driving force amplitude, f is the driving force period (for example, may be 0.05 Hz), and t is the driving force output time.

[0043] In an embodiment of the present invention, a kinematic model of the flexible actuator is first obtained based on the structure of each flexible actuator, and then the output force in the flexible actuator is adjusted using the constructed kinematic model, so that the output force of the active driving mechanism in each flexible actuator is in the form of a sine wave. This form of output force is relatively smooth and can minimize damage to the flexible actuator structure.

[0044] Regarding step 102:

[0045] In some implementations, step 102 includes:

[0046] Step S1, determining whether the output force of the active driving mechanism at the current moment is greater than a preset calibration threshold;

[0047] Step S2: If yes, then use the scaling factor formula to calibrate the scaling factors of the other linear displacement sensors respectively based on one of the linear displacement sensors;

[0048] Step S3: if not, take the next moment as the current moment and return to step S1;

[0049] Step S4, determining whether the difference between the current scaling factor and the previous scaling factor is greater than the calibration end threshold, if so, returning to step S3;

[0050] Step S5: if not, the scaling factor at the current moment is used as the scaling factor of other linear displacement sensors, so that the active drive mechanism and each linear displacement sensor are located on the same reference.

[0051] Considering that the working performance of the flexible actuator will change during the operation of the spacecraft, it may cause measurement errors of the active drive mechanism or the linear displacement sensor; therefore, in an embodiment of the present invention, before fault diagnosis is performed, the output force of the active drive mechanism is used as a judgment condition, and one of the linear displacement sensors is used as a reference to calibrate the other displacement sensors. In this way, the active drive mechanism and each linear displacement sensor can be located on the same reference, which is beneficial to enhance the accuracy of subsequent flexible actuator fault diagnosis.

[0052] In some embodiments, the scaling factor formula is as follows:

[0053]

[0054] Where, L mA (k) is the measured output displacement of the reference linear displacement sensor at the current moment, L mB (k) is the measured output displacement of the linear displacement sensor to be calibrated at the current moment, k cal is the coefficient of the scale factor calibration of the linear displacement sensor to be calibrated, λ Bcal (k) is the calibration value of the scale factor of the linear displacement sensor to be calibrated at the current moment, λ Bcal (k-1) is the calibration value of the scale factor of the linear displacement sensor to be calibrated at the previous moment.

[0055] For example, the flexible actuator includes two linear displacement sensors, which are respectively denoted as linear displacement sensor A and linear displacement sensor B. If at the current time k, the output force F(k) of the active drive mechanism is greater than F calmin (preset calibration threshold), the linear displacement sensor B (linear displacement sensor to be calibrated) can be calibrated with the linear displacement sensor A as the reference (reference linear displacement sensor) according to the above-mentioned scaling factor formula. During the calibration process, the scaling factor calibration coefficient of the linear displacement sensor to be calibrated is appropriately adjusted (for example, it can be 0.1), so that the linear displacement sensor B can be calibrated with high efficiency and high precision. Balanced adjustment; further, considering that the output force of the active drive mechanism is in the form of a sine wave, when the output force is small, the calibration of the linear displacement sensor will introduce errors. Therefore, if the output force F of the active drive mechanism at the current time k is i (k)<F calmin (preset calibration threshold) does not require calibration of the linear displacement sensor.

[0056] In the embodiment of the present invention, if the output force of the active driving mechanism is greater than the preset calibration threshold value, when calibrating the linear displacement sensor, k is greater than 1, that is, the linear displacement sensor needs to be calibrated at least twice, which can improve the accuracy of the calibration; then the calibration value λ of the scale factor at the current k moment is Bcal (k) and the scale factor calibration value λ at the previous k-1 time Bcal (k-1) and compare the difference with the calibration end threshold. Bcal (k)-λ Bcal (k-1)<λ min (calibration end threshold), the calibration of the linear displacement sensor B is ended, and the calibration value of the scale factor obtained by the calibration at the current time k is used as the scale factor of the linear displacement sensor B; if λ Bcal (k)-λ Bcal (k-1)>λ min (calibration end threshold), then the above-mentioned scaling factor formula is used to repeatedly calibrate it until the above-mentioned conditions are met.

[0057] It should be noted that in the embodiment of the present invention, the preset calibration threshold and the end calibration threshold can be determined according to the experience of those skilled in the art. For example, the preset calibration threshold can be F calmin It can be 15Nm, ending the calibration threshold λ min It can be 0.01.

[0058] For steps 104 to 106:

[0059] In some embodiments, the expected displacement of the active drive mechanism is calculated by the following formula:

[0060] L ref =F / k b

[0061] Where, L ref is the expected displacement of the active drive mechanism, F is the output force of the active drive mechanism, k b is the stiffness coefficient of the active drive mechanism of the flexible actuator.

[0062] The measured output values ​​of the active drive mechanism and the linear displacement sensor are directly related to the operating state of the flexible actuator. Therefore, in the embodiment of the present invention, the output force of the active drive mechanism within a period of time is collected and converted into an output displacement value, as well as the displacement output value of the calibrated linear displacement sensor, which are respectively subtracted from each other. The difference size after the subtraction and the corresponding diagnostic evaluation value are used to achieve accurate diagnosis of faults of various components in the flexible actuator (such as the active drive mechanism and the linear displacement sensor).

[0063] In some embodiments, the preset diagnostic coefficients include a first diagnostic coefficient, a second diagnostic coefficient, and a third diagnostic coefficient that increase in sequence.

[0064] In some implementations, step 106 includes:

[0065] After subtracting the expected displacement value of the active drive mechanism and the output displacement value of each calibrated linear displacement sensor, a plurality of displacement difference values ​​are obtained respectively; wherein each displacement difference value corresponds to two initial diagnostic evaluation values, and the initial diagnostic evaluation values ​​include the initial diagnostic evaluation value of the active drive mechanism and / or the initial diagnostic evaluation value of each linear displacement sensor;

[0066] Comparing each displacement difference with the first diagnostic coefficient respectively, if the displacement difference is less than the first diagnostic coefficient, increasing the two initial diagnostic evaluation values ​​corresponding thereto by one respectively;

[0067] If the displacement difference is greater than the first diagnostic coefficient and less than the second diagnostic coefficient, the two initial diagnostic evaluation values ​​corresponding thereto are respectively reduced by one;

[0068] If the displacement difference is greater than the second diagnostic coefficient and less than the third diagnostic coefficient, the two initial diagnostic evaluation values ​​corresponding thereto are respectively reduced by two;

[0069] Sort the calculated diagnostic evaluation values ​​by size to obtain the maximum diagnostic evaluation value;

[0070] The maximum diagnostic evaluation value is subtracted from the initial diagnostic values ​​of the active drive mechanism and the linear displacement sensor respectively. If the difference is greater than a determination threshold, it is determined that the active drive mechanism and / or the linear displacement sensor is faulty.

[0071] In the embodiment of the present invention, the linear displacement sensor A and the linear displacement sensor B are taken as examples. At this time, the initial diagnostic evaluation value includes the initial diagnostic evaluation value S of the active drive mechanism. ref , the initial diagnostic evaluation value S of the linear displacement sensor A A and the initial diagnostic evaluation value S of the linear displacement sensor B B First, the output force of the active drive mechanism at the current time k is collected and converted into the expected displacement value L ref , the output displacement value L of the linear displacement sensor A mA And the output displacement value L of the linear displacement sensor B mB , and subtract the three of them in pairs to get three displacement differences:

[0072] Δ LAB =L mA -L mB

[0073] Δ LA1 =L mA -L ref

[0074] Δ LA2 =L mB -L ref

[0075] In the formula, Δ LAB is the displacement difference between linear displacement sensors A and B, Δ LA1 is the displacement difference between the linear displacement sensor A and the expected displacement value of the active drive mechanism, Δ LA2 It is the displacement difference between the linear displacement sensor B and the expected displacement value of the active drive mechanism.

[0076] Each displacement difference corresponds to two initial diagnostic evaluation values, such as the displacement difference Δ LAB The initial diagnostic evaluation value S of the linear displacement sensor A is respectively A and the initial diagnostic evaluation value S of the linear displacement sensor B B , displacement difference Δ LA1 The initial diagnostic evaluation value S of the linear displacement sensor A is respectively A and the initial diagnostic evaluation value S of the active drive mechanism ref , displacement difference Δ LA2 The initial diagnostic evaluation value S of the linear displacement sensor B is B and the initial diagnostic evaluation value S of the active drive mechanism ref In the embodiments of the present invention, the initial diagnosis evaluation values ​​are all the same and can be set according to the requirements, for example, can be 100.

[0077] Afterwards, each displacement difference is compared with the first coefficient, the second coefficient and the third coefficient in turn, and the initial diagnostic evaluation value corresponding thereto is scored and evaluated according to the comparison results, specifically:

[0078] (1) If Δ LAB <Δ Lmin1 , then, S A , S B Increase by 1;

[0079] If Δ Lmin1 <Δ LAB <Δ Lmin2 , then, S A , S B All minus 1;

[0080] If Δ Lmin2 <Δ LAB <Δ Lmin3 , then, S A , SB Subtract 2 from both;

[0081] (2) If Δ LA1 <Δ Lmin1 , then, S A , S ref Increase by 1;

[0082] If Δ Lmin1 <Δ L1 <Δ Lmin2 , then, S A , S ref All minus 1;

[0083] If Δ Lmin2 <Δ L1 <Δ Lmin3 , then, S A , S ref Both are reduced by 2;

[0084] (3) If Δ L2 <Δ Lmin1 , then, S B , S ref Increase by 1;

[0085] If Δ Lmin1 <Δ L2 <Δ Lmin2 , then, S B , S ref All minus 1;

[0086] If Δ Lmin2 <Δ L2 <Δ Lmin3 , then, S B , S ref Subtract 2 from both;

[0087] After a period of time, the sizes of the obtained diagnostic evaluation values ​​are compared and sorted, and the largest diagnostic evaluation value is taken to subtract the initial diagnostic evaluation value, and the difference is further compared with the fault judgment threshold (for example, it can be 64), so as to realize the fault diagnosis of each component in the flexible actuator.

[0088] Specifically, if max(S A , S B , S ref )-S A >S min , then it is determined that the linear displacement sensor A is faulty;

[0089] If: max(S A , S B , S ref )-S B >S min, then it is determined that the linear displacement sensor B is faulty;

[0090] If: max(S A , S B , S ref )-S ref >S min , then it is determined that the active drive link is faulty; where max() is the maximum value operation.

[0091] In an embodiment of the present invention, three diagnostic coefficients with increasing sizes are set, and the displacement difference between the expected displacement value and the displacement value output by the linear displacement sensor is compared with the three diagnostic coefficients. The diagnostic evaluation value is scored based on the displacement difference in the interval of the three diagnostic coefficients. In this way, the accuracy and credibility of the flexible actuator fault diagnosis can be enhanced.

[0092] In summary, in the embodiment of the present invention, the above method can be used to diagnose the fault of each flexible actuator during the long-life operation of the spacecraft. Based on the diagnosis result, the faulty flexible actuator can be effectively isolated, the stable operation of the spacecraft on orbit can be achieved, and support can be provided for the design of the spacecraft's secondary composite control parameters.

[0093] like Figure 2 , Figure 3 As shown, an embodiment of the present invention provides a flexible actuator fault diagnosis device. The device embodiment can be implemented by software, or by hardware or a combination of software and hardware. From the hardware level, Figure 2 As shown in FIG. 1 , a hardware architecture diagram of a computing device where a flexible actuator fault diagnosis device provided by an embodiment of the present invention is located is shown in FIG. Figure 2 In addition to the processor, memory, network interface, and non-volatile memory shown in the figure, the computing device in which the device is located in the embodiment may also generally include other hardware, such as a forwarding chip responsible for processing messages, etc. Taking software implementation as an example, Figure 3 As shown, as a device in a logical sense, the CPU of the computing device in which it is located reads the corresponding computer program in the non-volatile memory into the internal memory and runs it.

[0094] This embodiment provides a flexible actuator fault diagnosis device, the flexible actuator includes a passive damping mechanism, an active driving mechanism and at least two linear displacement sensors;

[0095] The device includes:

[0096] An adjustment unit 301 is used to adjust the output force of the active driving mechanism based on the constructed kinematic model of the flexible actuator so that the output force is in a sinusoidal wave form;

[0097] The calibration unit 302 is used to calibrate the other displacement sensors using the output force of the active drive mechanism at each moment as a determination condition and using one of the linear displacement sensors as a reference, so that the active drive mechanism and each linear displacement sensor are located at the same reference;

[0098] A calculation unit 303, configured to obtain a desired displacement of the active driving mechanism according to an output force of the active driving mechanism;

[0099] The fault diagnosis unit 304 is used to compare the expected displacement value of the active drive mechanism and the calibrated output displacement value of each linear displacement sensor with the preset diagnosis coefficients after making a difference between them, so as to perform fault diagnosis on the active drive mechanism and each linear displacement sensor respectively.

[0100] In an embodiment of the present invention, the adjustment unit 301 can be used to execute step 100 in the above method embodiment, the calibration unit 302 can be used to execute step 102 in the above method embodiment, the calculation unit 303 can be used to execute step 104 in the above method embodiment, and the fault diagnosis unit 304 can be used to execute step 106 in the above method embodiment.

[0101] In one embodiment of the present invention, in the adjustment unit 301, the kinematic model of the flexible actuator is as follows:

[0102]

[0103] L mi =λ i x

[0104] Where m is the driving load mass of the flexible actuator, c is the damping coefficient of the passive damping mechanism of the flexible actuator, and k is b is the stiffness coefficient of the active drive mechanism of the flexible actuator, x is the motion displacement of the active drive mechanism of the flexible actuator, and are the first-order derivative and second-order derivative of the motion displacement of the active drive mechanism, F is the output force of the active drive mechanism, L mi is the output displacement of the i-th linear displacement sensor, λ i is the scale factor of the i-th linear displacement sensor.

[0105] In one embodiment of the present invention, the calibration unit 302 is used to perform the following operations when calibrating other displacement sensors using one of the linear displacement sensors as a reference, taking the output force of the active drive mechanism at each moment as a determination condition:

[0106] Step S1, determining whether the output force of the active driving mechanism at the current moment is greater than a preset calibration threshold;

[0107] Step S2: If yes, then use the scaling factor formula to calibrate the scaling factors of the other linear displacement sensors respectively based on one of the linear displacement sensors;

[0108] Step S3: if not, take the next moment as the current moment and return to step S1;

[0109] Step S4, determining whether the difference between the current scale factor calibration value and the previous scale factor calibration value is greater than the calibration end threshold, if so, returning to step S3;

[0110] Step S5: if not, the calibration value of the scale factor at the current moment is used as the scale factor of other linear displacement sensors, so that the active drive mechanism and each linear displacement sensor are located at the same reference.

[0111] In one embodiment of the present invention, in the calibration unit 302, the scaling factor formula is as follows:

[0112]

[0113] Where, L mA (k) is the measured output displacement of the reference linear displacement sensor at the current moment, L mB (k) is the measured output displacement of the linear displacement sensor to be calibrated at the current moment, k cal is the coefficient of the scale factor calibration of the linear displacement sensor to be calibrated, λ Bcal (k) is the calibration value of the scale factor of the linear displacement sensor to be calibrated at the current moment, λ Bcal (k-1) is the calibration value of the scale factor of the linear displacement sensor to be calibrated at the previous moment.

[0114] In one embodiment of the present invention, in the calculation unit 303, the expected displacement of the active driving mechanism is calculated by the following formula:

[0115] L ref =F / k b

[0116] Where, L ref is the expected displacement of the active drive mechanism, F is the output force of the active drive mechanism, k b is the stiffness coefficient of the active drive mechanism of the flexible actuator.

[0117] In one embodiment of the present invention, in the fault diagnosis unit 304, the preset diagnosis coefficients include a first diagnosis coefficient, a second diagnosis coefficient, and a third diagnosis coefficient that increase in sequence;

[0118] The fault diagnosis unit 304 performs the following operations when the expected displacement value of the active drive mechanism and the output displacement value of each linear displacement sensor after calibration are subtracted from each other and then compared with the preset diagnosis coefficients to perform fault diagnosis on the active drive mechanism and each linear displacement sensor respectively:

[0119] After subtracting the expected displacement value of the active drive mechanism and the output displacement value of each calibrated linear displacement sensor, a plurality of displacement difference values ​​are obtained respectively; wherein each displacement difference value corresponds to two initial diagnostic evaluation values, and the initial diagnostic evaluation values ​​include the initial diagnostic evaluation value of the active drive mechanism and / or the initial diagnostic evaluation value of each linear displacement sensor;

[0120] Comparing each displacement difference with the first diagnostic coefficient respectively, if the displacement difference is less than the first diagnostic coefficient, increasing the two initial diagnostic evaluation values ​​corresponding thereto by one respectively;

[0121] If the displacement difference is greater than the first diagnostic coefficient and less than the second diagnostic coefficient, the two initial diagnostic evaluation values ​​corresponding thereto are respectively reduced by one;

[0122] If the displacement difference is greater than the second diagnostic coefficient and less than the third diagnostic coefficient, the two initial diagnostic evaluation values ​​corresponding thereto are respectively reduced by two;

[0123] Sort the calculated diagnostic evaluation values ​​by size to obtain the maximum diagnostic evaluation value;

[0124] The maximum diagnostic evaluation value is subtracted from the initial diagnostic values ​​of the active drive mechanism and the linear displacement sensor respectively. If the difference is greater than a determination threshold, it is determined that the active drive mechanism and / or the linear displacement sensor is faulty.

[0125] It is understood that the structure illustrated in the embodiment of the present invention does not constitute a specific limitation on a flexible actuator fault diagnosis device. In other embodiments of the present invention, a flexible actuator fault diagnosis device may include more or fewer components than shown in the figure, or combine some components, or split some components, or arrange the components differently. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0126] The information interaction, execution process and other contents between the modules in the above-mentioned device are based on the same concept as the embodiment of the method of the present invention. For the specific contents, please refer to the description in the embodiment of the method of the present invention, and no further description is given here.

[0127] An embodiment of the present invention further provides a computing device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, a flexible actuator fault diagnosis method in any embodiment of the present invention is implemented.

[0128] An embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the processor executes a flexible actuator fault diagnosis method in any embodiment of the present invention.

[0129] Specifically, a system or device equipped with a storage medium can be provided, on which software program code that implements the functions of any of the above-mentioned embodiments is stored, and a computer (or CPU or MPU) of the system or device can be enabled to read and execute the program code stored in the storage medium.

[0130] In this case, the program code itself read from the storage medium can realize the function of any one of the above-mentioned embodiments, and thus the program code and the storage medium storing the program code constitute a part of the present invention.

[0131] The storage medium embodiments for providing the program code include a floppy disk, a hard disk, a magneto-optical disk, an optical disk (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), a magnetic tape, a non-volatile memory card, and a ROM. Alternatively, the program code can be downloaded from a server computer by a communication network.

[0132] In addition, it should be clear that the functions of any of the above embodiments can be implemented not only by executing the program code read by the computer, but also by enabling an operating system operating on the computer to complete part or all of the actual operations based on instructions from the program code.

[0133] In addition, it can be understood that the program code read from the storage medium is written to a memory provided in an expansion board inserted into the computer or to a memory provided in an expansion module connected to the computer, and then based on the instructions of the program code, a CPU installed on the expansion board or expansion module is enabled to perform part or all of the actual operations, thereby realizing the functions of any of the above-mentioned embodiments.

[0134] An embodiment of the present application also provides a computer-readable storage medium, on which is stored at least one instruction, at least one program, code set or instruction set, and the at least one instruction, at least one program, code set or instruction set is loaded and executed by a processor to implement a flexible actuator fault diagnosis method provided by the above-mentioned method embodiments.

[0135] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0136] A person of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk, etc., various media that can store program codes.

[0137] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flexible actuator fault diagnosis method, characterized in that: The flexible actuator includes a passive damping mechanism, an active driving mechanism and at least two linear displacement sensors; Methods include: The output force of the active driving mechanism is adjusted based on the constructed kinematic model of the flexible actuator so that the output force is in the form of a sine wave; Taking the output force of the active drive mechanism at each moment as a determination condition, calibrate the other displacement sensors using one of the linear displacement sensors as a reference, so that the active drive mechanism and each linear displacement sensor are located at the same reference; Obtaining a desired displacement of the active driving mechanism according to the output force of the active driving mechanism; The expected displacement value of the active drive mechanism and the calibrated output displacement value of each linear displacement sensor are subtracted from each other and then compared with preset diagnostic coefficients to perform fault diagnosis on the active drive mechanism and each linear displacement sensor respectively.

2. The method according to claim 1, characterized in that The kinematic model of the flexible actuator is as follows: L mi =λ i x Where m is the driving load mass of the flexible actuator, c is the damping coefficient of the passive damping mechanism of the flexible actuator, and k is b is the stiffness coefficient of the active drive mechanism of the flexible actuator, x is the motion displacement of the active drive mechanism of the flexible actuator, and are the first-order derivative and second-order derivative of the motion displacement of the active drive mechanism, F is the output force of the active drive mechanism, L mi is the output displacement of the i-th linear displacement sensor, λ i is the scale factor of the i-th linear displacement sensor.

3. The method according to claim 1, characterized in that The method of using the output force of the active driving mechanism at each moment as a determination condition and using one of the linear displacement sensors as a reference to calibrate other displacement sensors includes: Step S1, determining whether the output force of the active driving mechanism at the current moment is greater than a preset calibration threshold; Step S2: If yes, then use the scaling factor formula to calibrate the scaling factors of the other linear displacement sensors respectively based on one of the linear displacement sensors; Step S3: if not, take the next moment as the current moment and return to step S1; Step S4, determining whether the difference between the current scale factor calibration value and the previous scale factor calibration value is greater than the calibration end threshold, if so, returning to step S3; Step S5: if not, the calibration value of the scale factor at the current moment is used as the scale factor of other linear displacement sensors, so that the active drive mechanism and each linear displacement sensor are located at the same reference.

4. The method according to claim 3, characterized in that The scaling factor formula is as follows: Where, L mA (k) is the measured output displacement of the reference linear displacement sensor at the current moment, L mB (k) is the measured output displacement of the linear displacement sensor to be calibrated at the current moment, k cal is the coefficient of the scale factor calibration of the linear displacement sensor to be calibrated, λ Bcal (k) is the calibration value of the scale factor of the linear displacement sensor to be calibrated at the current moment, λ Bcal (k-1) is the calibration value of the scale factor of the linear displacement sensor to be calibrated at the previous moment.

5. The method according to claim 1, characterized in that The expected displacement of the active drive mechanism is calculated by the following formula: L ref =F / k b Where, L ref is the expected displacement of the active drive mechanism, F is the output force of the active drive mechanism, k b is the stiffness coefficient of the active drive mechanism of the flexible actuator.

6. The method according to any one of claims 1 to 5, characterized in that The preset diagnostic coefficients include a first diagnostic coefficient, a second diagnostic coefficient and a third diagnostic coefficient which increase in sequence; The expected displacement value of the active drive mechanism and the output displacement value of each linear displacement sensor after calibration are subtracted from each other and then compared with preset diagnostic coefficients to perform fault diagnosis on the active drive mechanism and each linear displacement sensor respectively, including: After subtracting the expected displacement value of the active drive mechanism and the output displacement value of each calibrated linear displacement sensor, a plurality of displacement difference values ​​are obtained respectively; wherein each displacement difference value corresponds to two initial diagnostic evaluation values, and the initial diagnostic evaluation values ​​include the initial diagnostic evaluation value of the active drive mechanism and / or the initial diagnostic evaluation value of each linear displacement sensor; Comparing each displacement difference with the first diagnostic coefficient respectively, if the displacement difference is less than the first diagnostic coefficient, increasing the two initial diagnostic evaluation values ​​corresponding thereto by one respectively; If the displacement difference is greater than the first diagnostic coefficient and less than the second diagnostic coefficient, the two initial diagnostic evaluation values ​​corresponding thereto are respectively reduced by one; If the displacement difference is greater than the second diagnostic coefficient and less than the third diagnostic coefficient, the two initial diagnostic evaluation values ​​corresponding thereto are respectively reduced by two; Sort the calculated diagnostic evaluation values ​​by size to obtain the maximum diagnostic evaluation value; The maximum diagnostic evaluation value is subtracted from the initial diagnostic values ​​of the active drive mechanism and the linear displacement sensor respectively. If the difference is greater than a determination threshold, it is determined that the active drive mechanism and / or the linear displacement sensor is faulty.

7. A flexible actuator fault diagnosis device, characterized in that: The flexible actuator includes a passive damping mechanism, an active driving mechanism and at least two linear displacement sensors; The device includes: An adjustment unit, used for adjusting the output force of the active driving mechanism based on the constructed kinematic model of the flexible actuator, so that the output force is in a sine wave form; A calibration unit, used to calibrate other displacement sensors using one of the linear displacement sensors as a reference, taking the output force of the active drive mechanism at each moment as a determination condition, so that the active drive mechanism and each linear displacement sensor are located at the same reference; a calculation unit, configured to obtain a desired displacement of the active drive mechanism according to an output force of the active drive mechanism; The fault diagnosis unit is used to compare the expected displacement value of the active drive mechanism and the calibrated output displacement value of each linear displacement sensor with the preset diagnosis coefficients after making a difference between them, so as to perform fault diagnosis on the active drive mechanism and each linear displacement sensor respectively.

8. A computing device, comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to execute the method according to any one of claims 1 to 6.

10. A computer program product, characterized in that The method comprises a computer program, wherein when the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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