CN115224991A

CN115224991A - Method and device for detecting locked rotor of stepping motor and computer readable medium

Info

Publication number: CN115224991A
Application number: CN202110420437.0A
Authority: CN
Inventors: 尹寿林; 董少华
Original assignee: Faurecia China Holding Co Ltd
Current assignee: Faurecia China Holding Co Ltd
Priority date: 2021-04-19
Filing date: 2021-04-19
Publication date: 2022-10-21
Also published as: DE102022109294A1

Abstract

The invention provides a method and a device for detecting locked rotor of a stepping motor. The stepper motor has a periodically varying drive current. The detection method comprises the following steps: dividing a single time period of the driving current into a first period and a second period, wherein the first period is earlier than the second period on a time axis; obtaining a minimum value and a maximum value of the driving current in the second period; and the condition for judging the locked rotor of the stepping motor comprises the following steps: the minimum value is less than a threshold value and the maximum value is greater than the threshold value. The method has the advantages of simple implementation method, small calculation amount and accurate result.

Description

Method and device for detecting locked rotor of stepping motor and computer readable medium

Technical Field

The invention mainly relates to the field of automobiles, in particular to a method and a device for detecting locked rotor of a stepping motor and a computer readable medium.

Background

The air conditioner air exchange system of the traditional automobile adopts a manually controlled air outlet, the adjustment of the air quantity and the air direction is realized by manually adjusting a thumb wheel, blades and the like by a driver, the adjustment efficiency is low, and the safe driving is not facilitated. Along with the development of automobile technology, more and more automobiles adopt an electric mode to control the air outlet, and the problem of the traditional air outlet is overcome to a certain extent. In the process of controlling the air outlet by adopting the stepping motor, the stepping motor is blocked due to the blockage of foreign matters or the arrival of the blades at the limit position, so that the control of the electric air outlet is failed. Therefore, the locked rotor of the stepping motor needs to be detected. However, according to the current detection technology, the accuracy of the locked rotor detection of the stepping motor still needs to be improved.

Disclosure of Invention

The invention aims to provide a detection method and a detection device for accurately detecting locked rotor of a stepping motor.

In order to solve the above technical problem, the present invention provides a method for detecting a locked rotor of a stepping motor, wherein the stepping motor has a periodically varying driving current, the method comprising: dividing a single time period of the driving current into a first period and a second period, wherein the first period is earlier than the second period on a time axis; obtaining a minimum value and a maximum value of the driving current in the second period; and the condition for judging the locked rotor of the stepping motor comprises the following steps: the minimum value is less than a threshold value and the maximum value is greater than the threshold value.

In an embodiment of the invention, the threshold is a rated maximum value of the driving current.

In an embodiment of the invention, the second period of time comprises the last 1/3 period of the single time cycle.

In an embodiment of the present invention, the method further includes: equally dividing the second time period into a first section and a second section, wherein the first section comprises the minimum value, and the second section comprises the maximum value; taking at least two first sampling values of the driving current in the first segment, wherein the first sampling values comprise the minimum value; taking at least two second sampling values of the driving current in the second segment, wherein the second sampling values comprise the maximum value; and judging the condition that the step motor is locked up, further comprising: all of the first sample values are less than the threshold value and all of the second sample values are greater than the threshold value.

In an embodiment of the present invention, the step of taking at least two first sampling values of the driving current in the first segment comprises: equally dividing the first section into at least two first subsections; and taking at least one first sampling value in each first subsection.

In an embodiment of the invention, the step of taking at least two second sampled values of the driving current in the second segment comprises: equally dividing the second segment into at least two second subsegments; and taking at least one second sampling value in each second subsection.

In an embodiment of the invention, the number of the first sample values is an integer multiple of 2, and the number of the second sample values is an integer multiple of 2.

In an embodiment of the invention, the first segment is earlier on the time axis than the second segment.

In an embodiment of the invention, the second segment comprises a last 5% period of the single time cycle.

In an embodiment of the present invention, the second period is a last 1/3 period of the single time cycle, and the step of obtaining the minimum value and the maximum value of the driving current in the second period includes: and equally dividing the second time period into four sub-time periods arranged in time sequence, taking the sampling value of the driving current at the end of the first sub-time period as the minimum value, and taking the sampling value of the driving current at the end of the third sub-time period as the maximum value.

In an embodiment of the present invention, the method further includes: obtaining a sampling value of the driving current at the beginning of the first sub-period as a third sampling value, obtaining a sampling value of the driving current at the beginning of the third sub-period as a fourth sampling value, and determining that the step motor is locked up further includes: the third sample value is less than the threshold value and the fourth sample value is greater than the threshold value.

The present invention further provides a device for detecting a locked rotor of a stepping motor, which comprises: a memory for storing instructions executable by the processor; a processor for executing the instructions to implement the detection method as described above.

The present invention also provides a computer readable medium storing computer program code, which when executed by a processor implements the detection method as described above.

According to the method and the device for detecting the locked rotor of the stepping motor, a single time period of the driving current is divided into the first time period and the second time period, the maximum value and the minimum value in the second time period are obtained, and the maximum value and the minimum value are compared with the threshold value, so that whether the locked rotor of the stepping motor occurs or not can be judged. The method has the advantages of simple implementation method, small calculation amount and accurate result.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the principle of the invention. In the drawings:

fig. 1 is an exemplary flowchart of a method for detecting a step motor stall according to an embodiment of the present invention;

FIG. 2 is a waveform diagram of a driving current of a stepping motor according to an embodiment of the present invention;

FIG. 3 is a waveform diagram of the driving current of the stepping motor in one cycle according to an embodiment of the present invention;

fig. 4 is a system block diagram of a device for detecting a step motor stalling according to an embodiment of the present invention.

Detailed Description

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings used in the description of the embodiments will be briefly introduced below. It is obvious that the drawings in the following description are only examples or embodiments of the application, from which the application can also be applied to other similar scenarios without inventive effort for a person skilled in the art. Unless otherwise apparent from the context, or stated otherwise, like reference numbers in the figures refer to the same structure or operation.

As used in this application and in the claims, the terms "a," "an," "the," and/or "the" are not intended to be inclusive in the singular, but rather are intended to include the plural, unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" are intended to cover only the explicitly identified steps or elements as not constituting an exclusive list and that the method or apparatus may comprise further steps or elements.

The relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

In the description of the present application, it is to be understood that the orientation or positional relationship indicated by the directional terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc., are generally based on the orientation or positional relationship shown in the drawings, and are used for convenience of description and simplicity of description only, and in the case of not making a reverse description, these directional terms do not indicate and imply that the device or element being referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore, should not be considered as limiting the scope of the present application; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

For ease of description, spatially relative terms such as "over 8230 \ 8230;,"' over 8230;, \8230; upper surface "," above ", etc. may be used herein to describe the spatial relationship of one device or feature to another device or feature as shown in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary terms "at 8230; \8230; 'above" may include both orientations "at 8230; \8230;' above 8230; 'at 8230;' below 8230;" above ". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, so that the scope of the present application is not to be construed as being limited. Further, although the terms used in the present application are selected from publicly known and used terms, some of the terms mentioned in the specification of the present application may be selected by the applicant at his or her discretion, the detailed meanings of which are described in relevant parts of the description herein. Further, it is required that the present application is understood not only by the actual terms used but also by the meaning of each term lying within.

Flow charts are used herein to illustrate operations performed by systems according to embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed in the exact order in which they are performed. Rather, various steps may be processed in reverse order or simultaneously. Meanwhile, other operations are added to or removed from these processes.

Fig. 1 is an exemplary flowchart of a method for detecting a step motor stall according to an embodiment of the present invention. The stepping motor according to the present invention has a periodically varying drive current. Referring to fig. 1, the detection method of this embodiment includes the steps of:

step S110: dividing a single time period of the driving current into a first period and a second period, wherein the first period is earlier than the second period on a time axis;

step S120: obtaining the minimum value and the maximum value of the driving current in the second period; and

step S130: the conditions for judging the locked rotor of the stepping motor comprise: the minimum value is less than a threshold and the maximum value is greater than the threshold.

Fig. 2 is a waveform diagram of a driving current of a stepping motor according to an embodiment of the present invention. Steps S110-S130 in the embodiment shown in FIG. 1 are described in detail below in conjunction with FIG. 2.

Referring to fig. 2, the horizontal axis represents a time axis t, and the vertical axis represents the driving current Id. The unit of the time axis t and the unit of the driving current Id are not limited in the present invention, and may be determined according to the power and model of the specific stepping motor.

As shown in fig. 2, the driving current Id is regularly repeated with a period T on a time axis T. Wherein, assuming the origin of coordinates O as the time zero, O-T1 represents the first period T1, T1-T2 represents the second period T2, and so on. The waveform of the drive current Id over 4 complete cycles is shown in fig. 2. In this specification, tn represents a period between Tn-1 and Tn.

It should be noted that fig. 2 is only an illustration and is not intended to limit the actual period, magnitude, and the like of the drive current Id of the stepping motor.

As shown in fig. 2, periods T1 and T2 show the waveform of the drive current Id in the normal state. Taking the period T1 as an example, the driving current Id is approximately 0 at the start O of the period T1, and with increasing time, the driving current Id increases exponentially, starts to grow slowly before reaching a half of one period, and tends to a straight line infinitely approaching or reaching a certain threshold Th in the last 1/2-1/3 period of one period. In the next period T2, the driving current Id is returned to 0 again, and the rule of the previous period T1 is repeated.

In the period T3 and the period T4, the waveform of the drive current Id fluctuates abnormally. The observation results from a plurality of tests show that the abnormal fluctuation has close relation with the stalling of the stepping motor, namely, when the stalling of the stepping motor occurs or the motor blade reaches the extreme position, the driving current Id of the stepping motor presents the waveform characteristics in the periods T3 and T4 in the graph of FIG. 2.

Taking the period T3 as an example, the driving current Id reaches an extreme value 210 around 1/2 of the period T3; then starts decreasing and reaches a minimum 220; thereafter, it begins to increase and reaches a maximum value 230. Where the minimum value 220 is less than the threshold Th and the maximum value 230 is greater than the threshold Th.

According to the above waveform observation result, the detection method of the present invention divides a single time period of the drive current Id into the first period and the second period in step S110.

Fig. 3 is a waveform diagram of a driving current of a stepping motor in one cycle according to an embodiment of the present invention. Fig. 3 is an enlarged view showing a waveform of the drive current Id in the period T3 in fig. 2. Referring to fig. 3, in step S110, a single time period of the driving current Id is divided into a first period S1 and a second period S2, wherein the first period S1 is earlier than the second period S2 on the time axis.

In some embodiments, the second period S2 comprises the last 1/3 period of the single time cycle. As shown in FIG. 3, in this embodiment, the second period S2 is the last 1/3 of the period T, i.e., from 2/3T to T. The driving current Id includes a minimum value 310 and a maximum value 320 during the second period S2.

In step S120, the minimum value 310 and the maximum value 320 of the driving current Id in the second period S2 are obtained, that is, 2 sampled values of the driving current Id are obtained in the second period S2. The invention does not limit how the 2 samples are obtained.

In step S130, it is determined whether the step motor is locked up according to the obtained 2 sampling values, i.e., the minimum value 310 and the maximum value 320. The conditions for judging the locked rotor of the stepping motor comprise: the minimum value 310 is less than the threshold Th, and the maximum value 320 is greater than the threshold Th.

According to the embodiment, the locked rotor detection of the stepping motor can be performed only by acquiring 2 sampling values in the second time interval S2, the process is simple, and the result is accurate.

In some embodiments, the threshold is a nominal maximum value of the drive current Id. Referring to fig. 2, during a period of the normal state, for example, during periods T1 and T2, the drive current Id approaches or almost reaches the rated maximum value at the end of the period. However, in the periods T3 and T4, since the stepping motor is locked up, causing abnormal fluctuation of the drive current Id, the maximum value 230 significantly exceeds the rated maximum value of the drive current Id.

In some embodiments, the detection method of the present invention further comprises the steps of:

step S140: the second period S2 is equally divided into a first segment S21 and a second segment S22, where the first segment S21 includes a minimum value 310 and the second segment S22 includes a maximum value 320. The average score here means an average score on the time axis.

Referring to fig. 3, the second period S2 is equally divided into a first segment S21 and a second segment S22. The illustration in fig. 3 is only for illustration, and the time lengths of the first segment S21 and the second segment S22 should be equal.

In the embodiment shown in fig. 3, the first segment S21 is earlier than the second segment S22 on the time axis t.

Step S150: in the first segment S21, at least two first sampling values of the driving current Id are taken, and the first sampling values include a minimum value 310.

Referring to fig. 3, in the first segment S21, a first sample point 311 is shown in addition to the minimum value 310 as a first sample value. That is, the sampling values of the drive current Id obtained from the first sampling point 311 and the minimum value 310 both belong to the first sampling value.

The first sample value shown in fig. 3 includes 2 sample values. In other embodiments, more than 2 samples may be taken in the first segment S21. In some embodiments, the number of first sample values is an integer multiple of 2.

In some embodiments, the step of taking the first sampled values of at least two driving currents Id in the first segment S21 in step S150 includes:

step S152: equally dividing the first segment S21 into at least two first subsegments; and

step S154: at least one first sampling value is taken in each first subsection.

Referring to fig. 3, the first segment S21 is divided into two first subsegments S31 and S32, and at least one sample point in each of the first subsegments S31 and S32 is taken as a first sample value. The time lengths of the first subsegments S31 and S32 should be equal.

The present invention does not limit the positions of the sampling points taken in the first subsegments S31 and S32. In the embodiment shown in fig. 3, the first sampling point 311 is located at the beginning of the first subsection S31. The minimum 310 is located at the end of the first subsection S31 or at the beginning of the first subsection S32.

Step S160: in the second segment S22, at least two second sampled values of the driving current Id are taken, and the second sampled values include the maximum value 320.

Referring to fig. 3, in the second segment S22, a second sample point 321 is shown in addition to the maximum value 320 as a second sample value. That is, the sampling values of the drive current Id obtained from the second sampling point 321 and the maximum value 320 both belong to the second sampling value.

The second sample values shown in fig. 3 include 2 sample values. In other embodiments, more than 2 sample values may be taken in the second segment S22. In some embodiments, the number of second sample values is an integer multiple of 2.

In some embodiments, the step of taking the second sample values of at least two driving currents Id in the second segment S22 in the step S160 includes:

step S162: equally dividing the second segment S22 into at least two second subsegments; and

step S164: at least one second sampling value is taken in each second subsection.

Referring to fig. 3, the second segment S22 is divided into two second subsegments S41 and S42, and at least one sample point is taken as a second sample value in each of the second subsegments S41 and S42. The time lengths of the second subsegments S41 and S42 should be equal.

The present invention does not limit the positions of the sampling points taken in the second subsegments S41, S42. In the embodiment shown in fig. 3, the second sampling point 321 is located at the beginning of the second sub-segment S41. The maximum 320 is located at the end of the second sub-segment S41 or at the beginning of the second sub-segment S42.

Step S170: the condition for judging the locked rotor of the stepping motor further comprises the following steps: all of the first sample values are less than the threshold value and all of the second sample values are greater than the threshold value.

In step S170, all the first sampling values are compared with the threshold Th, all the second sampling values are compared with the threshold Th, and whether the step motor is locked or not is determined according to the comparison result.

As shown in fig. 3, in some embodiments, the second period S2 is the last 1/3 period of a single time cycle, and the step of obtaining the minimum value and the maximum value of the driving current Id within the second period S2 in step S120 includes:

step S180: the second period S2 is equally divided into four sub-periods arranged in time series, with the sample value of the drive current Id at the end of the first sub-period as the minimum value, and the sample value of the drive current Id at the end of the third sub-period as the maximum value.

Referring to fig. 3, the second period S2 is equally divided into four sub-periods S31, S32, S41, S42. The sampled value of the driving current Id at the end of the first sub-period S31 is the minimum value 310, and the sampled value of the driving current Id at the end of the third sub-period S41 is the maximum value 320.

From step S180, 2 sample points, i.e., a minimum value 310 and a maximum value 320, can be obtained. And judging whether the step motor is locked by using the sampling values of the driving current Id of the 2 sampling points.

In some embodiments, after step S180, the method may further include:

step S190: obtaining a sampling value of the driving current Id at the beginning of the first sub-period S31 as a third sampling value 311, obtaining a sampling value of the driving current Id at the beginning of the third sub-period S41 as a fourth sampling value 321, and determining that the step motor has the locked-rotor condition further includes: the third sample value 311 is smaller than the threshold Th and the fourth sample value 321 is larger than the threshold Th.

In this embodiment, the third sample value 311 in step S190 is the same sample point as the first sample point 311 in step S150; the fourth sampling point 321 in step S190 is the same sampling point as the second sampling point 321 in step S160.

According to the embodiment, it is equivalent to uniformly taking four sampling points in the second time interval S2, wherein the four sampling points include the minimum value 310 and the maximum value 320, and determining whether the step motor is locked rotor according to the determination conditions in step S190, so as to determine whether the step motor is locked rotor simply and accurately.

Figure 3 shows a preferred embodiment of the present invention. After many times of experiments, it is found that when the stepping motor is blocked by foreign matters or the blade reaches the limit position, the driving current Id exhibits characteristics similar to sinusoidal fluctuation in the last 1/3 period of one period T, as shown by the waveform in the second period S2 in fig. 3. Therefore, four sampling points are uniformly taken in the second period S2 of the drive current Id so that a minimum value 310 and a maximum value 320 of the drive current Id within the second period S2 are included, a third sampling value 311 earlier than the minimum value 310 on the time axis and having a current value larger than the minimum value 310, and a fourth sampling value 321 earlier than the maximum value 320 on the time axis and having a current value smaller than the maximum value 320 are included. The minimum value 310 and the third sampling value 311 are both smaller than the rated maximum value of the driving current Id, and the maximum value 320 and the fourth sampling value 321 are both larger than the rated maximum value of the driving current Id, at this time, it is determined that the step motor has locked rotor. According to the embodiment, the locked rotor of the stepping motor can be accurately judged only by obtaining four sampling points in the second time interval S2, and the method has the advantage of small calculation amount.

In some embodiments, the second segment S22 includes the last 5% period of the single cycle. Referring to FIG. 3, the start point of the second segment S22 on the time axis t is at least 95% T. The reason for this is that the maximum value 320 will appear in the interval of 95% T to T according to the results obtained by the experiment.

The invention also comprises a detection device for the locked rotor of the stepping motor, which comprises a memory and a processor. Wherein the memory is configured to store instructions executable by the processor; the processor is configured to execute the instructions to implement the apparatus for detecting a step motor stall as described above.

Fig. 4 is a system block diagram of a device for detecting a step motor stalling according to an embodiment of the present invention. Referring to fig. 4, the detection device 400 may include an internal communication bus 401, a processor 402, a Read Only Memory (ROM) 403, a Random Access Memory (RAM) 404, and a communication port 405. When used on a personal computer, the detection apparatus 400 may also include a hard disk 406. An internal communication bus 401 may enable data communication between the components of the detection apparatus 400. The processor 402 may make the determination and issue the prompt. In some embodiments, processor 402 may be comprised of one or more processors. The communication port 405 may enable data communication of the detection apparatus 400 with the outside. In some embodiments, the detection device 400 may send and receive information and data from a network through the communication port 405. The detection apparatus 400 may also include various forms of program storage units and data storage units, such as a hard disk 406, read Only Memory (ROM) 403 and Random Access Memory (RAM) 404, capable of storing various data files for computer processing and/or communication, as well as possible program instructions for execution by the processor 402. The processor executes these instructions to implement the main parts of the method. The results processed by the processor are communicated to the user device through the communication port and displayed on the user interface.

The above-mentioned method for detecting the locked-rotor of the stepping motor can be implemented as a computer program, stored in the hard disk 406, and loaded into the processor 402 for execution, so as to implement the data processing method of the present application.

The present invention also includes a computer readable medium having stored thereon computer program code which, when executed by a processor, implements the method of detecting a step motor stall as described above.

When the method for detecting the locked rotor of the stepping motor is implemented as a computer program, the computer program may be stored in a computer-readable storage medium as an article of manufacture. For example, computer-readable storage media can include but are not limited to magnetic storage devices (e.g., hard disk, floppy disk, magnetic strips), optical disks (e.g., compact Disk (CD), digital Versatile Disk (DVD)), smart cards, and flash memory devices (e.g., electrically erasable programmable read-only memory (EPROM), card, stick, key drive). In addition, various storage media described herein can represent one or more devices and/or other machine-readable media for storing information. The term "machine-readable medium" can include, without being limited to, wireless channels and various other media (and/or storage media) capable of storing, containing, and/or carrying code and/or instructions and/or data.

It should be understood that the above-described embodiments are illustrative only. The embodiments described herein may be implemented in hardware, software, firmware, middleware, microcode, or any combination thereof. For a hardware implementation, the processor may be implemented within one or more Application Specific Integrated Circuits (ASICs), digital Signal Processors (DSPs), digital Signal Processing Devices (DSPDs), programmable Logic Devices (PLDs), field Programmable Gate Arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, and/or other electronic units designed to perform the functions described herein, or a combination thereof.

Aspects of the present application may be embodied entirely in hardware, entirely in software (including firmware, resident software, micro-code, etc.) or in a combination of hardware and software. The above hardware or software may be referred to as "data block," module, "" engine, "" unit, "" component, "or" system. The processor may be one or more Application Specific Integrated Circuits (ASICs), digital Signal Processors (DSPs), digital signal processing devices (DAPDs), programmable Logic Devices (PLDs), field Programmable Gate Arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, or a combination thereof. Furthermore, aspects of the present application may be represented as a computer product, including computer readable program code, embodied in one or more computer readable media. For example, computer-readable media can include, but are not limited to, magnetic storage devices (e.g., hard disk, floppy disk, magnetic tape \8230;), optical disks (e.g., compact disk CD, digital versatile disk DVD \8230;), smart cards, and flash memory devices (e.g., card, stick, key drive \8230;).

The computer readable medium may comprise a propagated data signal with the computer program code embodied therein, for example, on a baseband or as part of a carrier wave. The propagated signal may take any of a variety of forms, including electromagnetic, optical, and the like, or any suitable combination. The computer readable medium can be any computer readable medium that can communicate, propagate, or transport the program for use by or in connection with an instruction execution system, apparatus, or device. Program code on a computer readable medium may be propagated over any suitable medium, including radio, electrical cable, fiber optic cable, radio frequency signals, or the like, or any combination of the preceding.

Having thus described the basic concept, it will be apparent to those skilled in the art that the foregoing disclosure is by way of example only, and is not intended to limit the present application. Various modifications, improvements and adaptations to the present application may occur to those skilled in the art, though not expressly described herein. Such alterations, modifications, and improvements are intended to be suggested herein and are intended to be within the spirit and scope of the exemplary embodiments of this application.

Also, this application uses specific language to describe embodiments of the application. Reference throughout this specification to "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic described in connection with at least one embodiment of the present application is included in at least one embodiment of the present application. Therefore, it is emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, some features, structures, or characteristics of one or more embodiments of the present application may be combined as appropriate.

Where numerals describing the number of components, attributes or the like are used in some embodiments, it is to be understood that such numerals used in the description of the embodiments are modified in some instances by the modifier "about", "approximately" or "substantially". Unless otherwise indicated, "about", "approximately" or "substantially" indicates that the number allows a variation of ± 20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximations that may vary depending upon the desired properties of the individual embodiments. In some embodiments, the numerical parameter should take into account the specified significant digits and employ a general digit preserving approach. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the range are approximations, in the specific examples, such numerical values are set forth as precisely as possible within the scope of the application.

Claims

1. A method of detecting locked rotor of a stepping motor having a periodically varying drive current, comprising:

dividing a single time cycle of the driving current into a first period and a second period, wherein the first period is earlier than the second period on a time axis;

obtaining a minimum value and a maximum value of the driving current in the second period; and

the conditions for judging the locked rotor of the stepping motor comprise: the minimum value is less than a threshold value and the maximum value is greater than the threshold value.

2. The detection method of claim 1, wherein the threshold value is a rated maximum value of the drive current.

3. The detection method of claim 1, wherein the second time period comprises a last 1/3 time period of the single time cycle.

4. The detection method of claim 1, further comprising: equally dividing the second time period into a first section and a second section, wherein the first section comprises the minimum value, and the second section comprises the maximum value;

taking at least two first sampling values of the driving current in the first segment, wherein the first sampling values comprise the minimum value;

taking at least two second sampling values of the driving current in the second segment, wherein the second sampling values comprise the maximum value; and

the step motor locked-rotor condition judgment further comprises the following steps: all of the first sample values are less than the threshold value and all of the second sample values are greater than the threshold value.

5. The detection method of claim 4, wherein the step of taking at least two first sample values of the drive current in the first segment comprises:

equally dividing the first section into at least two first subsections; and

and at least one first sampling value is taken in each first subsection.

6. The detection method of claim 4, wherein the step of taking at least two second sample values of the drive current in the second segment comprises:

equally dividing the second segment into at least two second subsegments; and

and at least one second sampling value is taken in each second subsection.

7. The detection method according to claim 4, wherein the number of the first sample values is an integer multiple of 2, and the number of the second sample values is an integer multiple of 2.

8. The detection method according to claim 4, wherein the first section is earlier than the second section on the time axis.

9. The detection method of claim 8, wherein the second segment comprises a last 5% period of the single time cycle.

10. The detection method according to claim 3, wherein the second period is a last 1/3 period of the single time cycle, and the step of obtaining the minimum value and the maximum value of the driving current in the second period includes: and equally dividing the second time period into four sub-time periods arranged in time sequence, taking the sampling value of the driving current at the end of the first sub-time period as the minimum value, and taking the sampling value of the driving current at the end of the third sub-time period as the maximum value.

11. The detection method of claim 10, further comprising: obtaining a sampling value of the driving current at the beginning of the first sub-period as a third sampling value, obtaining a sampling value of the driving current at the beginning of the third sub-period as a fourth sampling value, and determining that the step motor is locked up further includes: the third sample value is less than the threshold value and the fourth sample value is greater than the threshold value.

12. A stepping motor stalling detection device, comprising:

a memory for storing instructions executable by the processor;

a processor for executing the instructions to implement the detection method of any one of claims 1-11.

13. A computer-readable medium having stored thereon computer program code which, when executed by a processor, implements the detection method according to any one of claims 1-11.