KR101862111B1 - Apparatus and method for step motor stall detection - Google Patents

Abstract

Disclosed are a method for detecting a stall of a step motor by grasping a degree of distortion of a current profile and an apparatus thereof. The method comprises the steps of: (A) converting a reference current profile according to a supply voltage of a step motor into a database; (B) measuring the supply voltage to a step motor; (C) measuring a current at regular intervals while the current flows through a coil of the step motor; (D) calculating a current profile according to the measured supply voltage and the measured current; (E) calculating a sum of difference between the calculated current profile and the reference current profile; and (F) determining a state of a stall of the step motor based on the sum of the difference between the calculated current profile and the reference current profile.

Description

TECHNICAL FIELD [0001] The present invention relates to a stall detection method,

And more particularly, to an apparatus and method for stall detection of a step motor.

Unless otherwise indicated herein, the contents set forth in this section are not prior art to the claims of this application and are not to be construed as prior art to be included in this section.

Step motor An electric motor that rotates at a constant angle by a pulse-like voltage. The motor is a motor whose rotational angle is adjusted in proportion to the number of input pulse signals and whose rotational speed is controlled in proportion to the frequency of the input pulse signal. Specifically, the step motor is not a continuous rotation, but a stepwise motor that moves and fixes the position at a high speed, and is used mainly in a computer or a digital controlled device. In a hard disk or a CD drive, It is also used to drive the arm to position the head on the correct track. In general, a motor that rotates a certain angle every time a drive pulse is received is called a stepping motor or a pulse motor. Most of the dome camera servo motors used in CCTV use pulse motors. Stepping motors are also used in a variety of electronic devices, such as throttle valve actuators, vent flap control in air conditioning systems, and door-mirror seat adjustment (including memory).

Since the stepper motor rotates, a stall phenomenon in which the output shaft rotation relative to the input rotational speed is stopped may occur during driving by the hydrodynamic fluid transmission device such as a coupling torque converter. Conventionally, such a stall phenomenon is detected by detecting an output signal phase delay with respect to an input signal in a frequency response. Specifically, as shown in FIG. 1, when an abnormal value of a current or a voltage is sensed, a phase delay is detected and discriminated. However, the method of determining the stall by detecting the phase delay of the coil current requires a relatively large number of parts, and there is a limitation that it is only possible to determine whether or not the stall occurs by detecting the phase delay.

Korean Patent Laid-Open No. 10-2016-0131688 (November 16, 2016)

There is provided a stall detecting method and apparatus of a step motor for detecting a stall state of a step motor by measuring a current flowing through a coil to calculate an error between a current profile in a normal operation state and an error in a measured current profile, .

A stall detecting method of a stepping motor according to an embodiment of the present invention includes the steps of: (A) converting a reference current profile according to a step motor supply voltage into a database; (B) measuring a supply voltage to the stepper motor; (C) measuring a current at regular intervals while a current flows through a coil of the step motor; (D) calculating a current profile according to the measured supply voltage and the measured current; (E) calculating a sum of the difference between the calculated current profile and the reference current profile; And (F) determining a step motor stall state based on the sum of the difference between the calculated current profile and the reference current profile; .

    According to another aspect of the present invention, there is provided a stall detecting apparatus for a step motor, comprising: a database storing a reference current profile according to a supply voltage of a step motor; A profile generation module that measures a supply voltage to the stepper motor and measures a current at regular intervals while a current flows through the coil of the stepper motor to calculate a measured current supply profile and a current profile according to the measured current; And a sensing module for calculating the sum of the difference between the calculated current profile and the reference current profile and grasping the step motor stall state based on the sum of the difference between the calculated current profile and the reference current profile; .

Since the stall detection device of the step motor as described above can detect the stall of the step motor by using the software, it is possible to improve the circuit integration efficiency of the step motor, and if the stall of the motor is stalled, The details of the occurrence can be grasped.

It should be understood that the effects of the present invention are not limited to the above effects and include all effects that can be deduced from the detailed description of the present invention or the configuration of the invention described in the claims.

1 is a diagram for explaining an example of a current profile and a phase delay of a current motor;
2 is a block diagram showing a schematic configuration of a step motor stall detecting apparatus according to an embodiment
3 is a block diagram showing the configuration of the step motor stall detecting apparatus according to the embodiment in more detail.
4 is a flowchart showing a data processing flow for the stall state detection method according to the embodiment.
5A is a graph showing the relationship between the reference current profile graph example
5B is a view showing a current profile according to an embodiment;

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like numbers refer to like elements throughout.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions in the embodiments of the present invention, which may vary depending on the intention of the user, the intention or the custom of the operator. Therefore, the definition should be based on the contents throughout this specification.

2 is a block diagram showing a schematic configuration of a step motor stall sensing apparatus according to an embodiment.

Referring to FIG. 2, the step motor stall sensing apparatus may include a database 110, a profile generation module 130, and a sensing module 150. The term " module ", as used herein, should be interpreted to include software, hardware, or a combination thereof, depending on the context in which the term is used. For example, the software may be machine language, firmware, embedded code, and application software. As another example, the hardware may be a circuit, a processor, a computer, an integrated circuit, an integrated circuit core, a sensor, a micro-electro-mechanical system (MEMS), a passive device, or a combination thereof.

The database 110 stores a reference current profile according to the supply voltage of the step motor, a rotation angle profile of the shaft according to the current and the voltage, and stores a series of data required for step motor stall detection according to the present disclosure.

The profile generation module 130 measures the supply voltage to the stepper motor and measures the current at regular intervals while the current flows through the coil of the stepper motor to calculate the measured supply voltage and current profile according to the measured current.

The sensing module 150 calculates the sum of the difference between the calculated current profile and the reference current profile and grasps the step motor stall state based on the sum of the difference between the calculated current profile and the reference current profile.

3 is a block diagram showing a more detailed configuration of the step motor stall detecting apparatus according to the embodiment.

3, the profile generation module 130 may include a measurement unit 131 and a profile calculation unit 133. The detection module 150 may include a decision coefficient calculation unit 151, (153) and a stall state sensing unit (155).

The measurement unit 131 of the profile generation module 130 measures the supply voltage to the stepper motor and measures the average of the measured current and coil current measurement value per supply voltage.

The profile calculating unit 133 calculates the measured current profile for each supply voltage. For example, the current profile may mean current amount information on time and voltage change, such as a graph of a current amount change and a current amount data according to a supply voltage with respect to time.

The determination coefficient calculator 151 of the sensing module 150 calculates the determination coefficient R ² using the current profile F (Xi) with respect to the reference time and the reference voltage through Equation (1).

The coefficient of determination in this disclosure is a statistical measure of how well a least squares curve is appropriate for a given data when evaluating the curve by least squares.

     [Equation 1]

Xi: Measurement time Yi: Coil current measurement value Y: Coil current measurement value average

F (Xi): current profile for the reference voltage over a reference time

As shown in FIG. 5A, the stall state sensing unit 155 recognizes the step motor stall state using the calculated decision coefficient. For example, it is possible to compare the calculated decision coefficient with the stored decision coefficient through the stall state database according to the previously stored decision coefficient, and to determine the stall state of the decision coefficient calculated based on the stall state of the decision coefficient with a degree of similarity exceeding a certain level have.

The error sum calculator 153 calculates the error sum of the current profile F (Xi) and the coil current measurement value Yi with respect to the reference voltage for the reference time through Equation (2) .

&Quot; (2) "

  (I = 1 to n), Err =? (| Yi - F (Xi)

  Xi: Measurement time Yi: Coil current measurement value

  F (Xi): current profile for the reference voltage over a reference time

 The stall state sensing unit 155 grasps the step motor stall state using the calculated error sum. For example, the stall state sensing unit 155 recognizes the stall state of the step motor through the reference current profile stored in the database, the error rate of the measured current, and the degree of distortion of the measured error. According to the embodiment, the stall state sensing unit 155 recognizes whether the step motor is stalled or not, and when the stall state is detected, detailed information on the stall state, such as the output shaft rotation angle, based on the difference between the calculated current profile and the reference current profile Can be calculated.

4 is a flowchart illustrating a data processing flow for a stall state detection method according to an embodiment.

In order to make the reference current profile according to the supply voltage of the stepper motor a database, a reference current profile according to the supply voltage is calculated (S410). As shown in FIG. 5A showing an example of the reference current profile graph, the reference current profile can be calculated by inputting the voltage supplied to the stepper motor at 10V, 12V, 14V, etc. and measuring the current with respect to the input voltage and time.

Thereafter, the supply voltage to the stepper motor is measured (S420), the current is measured at regular intervals while the current flows through the coil of the stepper motor, and the current profile is calculated according to the measured supply voltage and the measured current (S430).

The error between the calculated current profile and the reference current profile is calculated and the sum of the errors is calculated (S440).

If the sum of the calculated errors is equal to or greater than the set value, the stall state of the step motor is grasped (S460). If the sum of the errors is not equal to or greater than the set value, the supply voltage and current are measured again.

In the embodiment, the step motor stall state is grasped based on the calculated current profile and the reference current profile. 5B is a diagram showing a current profile according to an embodiment. As shown in FIG. 5B, the current profile in the unstalled state is converted into a database, and the current with respect to the voltage applied to the stepper motor is measured. Thereafter, the measured current profile is compared with the time-based measured value of the current profile in the steady state, and the stall state and the stall state can be grasped according to the error of the current in the steady state and the degree of graph distortion. In the embodiment, the output shaft rotation angle can be calculated based on the difference between the calculated current profile and the reference current profile in the stall state.

It is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. It is not limited to the embodiment.

110: Database
130: Profile creation module
131: Measuring section 133: Profile calculating section
150: Detection module
151: determination coefficient computing unit 153: error sum computing unit
155: stall state detection unit

Claims (8)

A method of stall detection of a stepping motor,
(A) converting a reference current profile according to a step motor supply voltage into a database;
(B) measuring a supply voltage to the stepper motor;
(C) measuring a current at regular intervals while a current flows through a coil of the step motor;
(D) calculating a current profile according to the measured supply voltage and the measured current;
(E) calculating a sum of the difference between the calculated current profile and the reference current profile; And
(F) determining a step motor stall state based on a sum of the difference between the calculated current profile and the reference current profile; Including the
(F) recognizing the step motor stall state; The
The determination coefficient R ² using the current profile F (Xi) with respect to the reference voltage with respect to the reference time is expressed by Equation 1,

(i = 1 to n, Xi: measurement time Yi: coil current measurement value, and Y: coil current measurement value average). And
Determining a step motor stall state by using the calculated decision coefficient; And a stall detecting step of detecting a stall of the step motor.
delete The method according to claim 1, further comprising the steps of: (F) recognizing a step motor stall state; The
The sum of the errors of the current profile F (Xi) and the coil current measurement value Yi with respect to the reference time is expressed by the following equation (2): Err =? (Yi-F i = 1 to n, Xi: measurement time Yi: coil current measurement value, and Y: coil current measurement value average); And
Determining a step motor stall state based on the calculated error sum;
And a stall detecting step of detecting a stall of the step motor.
The method according to claim 1, further comprising the steps of: (F) recognizing a step motor stall state; The
Wherein the stall detection means detects the stall state of the step motor and calculates an output shaft rotation angle based on a difference between the calculated current profile and the reference current profile when the stall state is stalled.
A stall sensing apparatus for a stepping motor, comprising:
A database storing a reference current profile according to a supply voltage of the stepper motor;
A profile generation module measuring a supply voltage to the stepper motor and measuring a current at a constant cycle while a current flows through a coil of the stepper motor to calculate a current profile according to the measured supply voltage and the measured current; And
A sensing module for calculating the sum of the difference between the calculated current profile and the reference current profile and for grasping the step motor stall state based on a sum of the difference between the calculated current profile and the reference current profile; And
The sensing module
The coefficient of determination R ² using the current profile F (Xi) with respect to a reference time with a reference voltage equation ^{1, R 2 = 1 - Σ} (Yi-Y) 2 / Σ (Yi - F (Xi)) 2, (i = 1 to n, Xi: measurement time Yi: coil current measurement value, and Y: coil current measurement value average); And
A stall state sensing unit for sensing a step motor stall state using the calculated decision coefficient; Wherein the stall detecting device includes a step motor.
delete 6. The apparatus of claim 5, wherein the sensing module
The sum of the errors of the current profile F (Xi) and the coil current measurement value Yi with respect to the reference time is expressed by the following equation (2): Err =? (Yi-F (i = 1 to n, Xi: measured time Yi: coil current measured value, and Y: coil current measured value average).
delete

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