KR101050164B1 - Linear motor and control method - Google Patents

Abstract

Disclosed are a linear motor and a control method thereof capable of simplifying the structure and improving stability and reliability. A stator having a plurality of permanent magnets arranged alternately in polarity, a mover linearly driven by interaction with the stator, and a plurality of linears provided on the mover to have a phase difference to measure the phase of the mover through polarity determination The linear motor control method includes a hall sensor and controls the moving distance of the mover without a separate scale by linearly detecting magnetic flux according to the polarity of each permanent magnet through a plurality of linear hall sensors. Generating a sine curve analog signal for the change, converting the sinusoidal analog signal into a pulse signal, and controlling the moving distance of the mover using the pulse signal.

Linear motor, stator, permanent magnet, mover, linear hall sensor, pole pitch

Description

LINEAR MOTOR AND CONTROL METHOD THERE OF

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motor, and more particularly, to a linear motor capable of simplifying a structure and improving stability and reliability, and a control method thereof.

Since linear motors can directly generate linear driving force, they do not require a separate mechanical converter, and because they operate linearly in a non-contact motion method, they can operate at high speed and quietly, and are capable of precise operation. Therefore, it is widely used in various industries.

In general, the linear motor includes a stator in which permanent magnets are alternately arranged in polarity and a mover in which a mover coil is wound around the mover core, and a magnetic force generated in the mover coil as a current is applied to the mover coil. The thrust of the straight line is generated by the interaction between and the magnetic force of the permanent magnet.

In addition, the linear motor must inevitably detect the position information of the mover. That is, if the positional information of the mover is not accurately detected when the linear motor is driven, it is difficult to move to the exact position required, and the stability of the thrust and the speed is lowered. The position relative to the coordinate reference point) and the position of movement must be accurately detected.

One of the methods for detecting the position information of the mover in the linear motor, which is conventionally installed on the mover side to detect the phase of the mover using a hall sensor that measures the magnetic flux of the stator permanent magnet, and is installed on the stator side. A method for detecting the moving position (movement amount) of the mover using a sensor head installed on the scale and the mover side to detect the linear scale has been proposed.

However, conventionally, since a separate linear scale has to be provided in order to detect the moving amount of the mover, the structure is complicated, manufacturing cost and manufacturing time are excessively consumed, and there is a problem in that it is not economical. That is, since the precision of the linear scale greatly affects the driving reliability and stability of the linear motor, the linear scale should be able to be manufactured with very high precision, but the linear scale with high precision is very expensive, thus increasing the production cost. There is a problem.

The present invention provides a linear motor and a control method thereof that can simplify the structure and manufacturing process.

In particular, the present invention provides a linear motor and a control method thereof capable of detecting an absolute position and a moving position of a mover by using a linear hall sensor and a permanent magnet without removing a separate linear scale.

In addition, the present invention can improve the driving stability and reliability, and provides a linear motor and a control method thereof that can reduce the production cost.

According to a preferred embodiment of the present invention for achieving the above object of the present invention, a stator having a plurality of permanent magnets of alternating polarity, a linearly driven mover by interaction with the stator, and a phase difference It includes a plurality of linear hall sensor provided on the mover to measure the phase of the mover by polarity determination, the control method of the linear motor to control the moving distance of the mover without a separate scale, through a plurality of linear hall sensor Linearly detecting the magnetic flux according to the polarity of each permanent magnet to generate a sine curve analog signal for each polarity change of the permanent magnet, converting the sinusoidal analog signal into a pulse signal, and using a pulse signal Controlling the moving distance of the mover.

The present invention excludes a separate linear scale for sensing the amount of movement of the mover with respect to the stator, and linearly detects the magnetic flux according to the polarity of the permanent magnet to provide a sine curve analog signal for a change in polarity of each permanent magnet. It is configured to control the moving distance of the mover by using the linear hall sensor to generate. In other words, the phase of the mover for the permanent magnet is checked by using a general hall sensor that simply outputs a change in the polarity of the magnet as an on / off signal, and the moving amount of the mover is measured through a separate linear scale. Had to be detected. However, in the present invention, the amount of movement of the mover can be controlled by checking the phase of the mover with respect to the permanent magnet using a sinusoidal analog signal detected through the linear hall sensor and calculating an input pulse signal.

On the other hand, since the arrangement interval between the permanent magnets is difficult to have a certain or more high precision due to the machining error and manufacturing error of the permanent magnet, an initialization step for correcting the drive error of the mover due to the error of the permanent magnet may be included. For example, the initializing of the linear motor may include: arranging the mover at a predetermined reference position, driving the mover at a constant speed, and sequentially scanning the lengths between the permanent magnets with the linear hall sensor, and a sine wave output through the linear hall sensor. Multiplying the analog signal to calculate unit pole pitches corresponding to the lengths between the permanent magnets, and storing the calculated unit pole pitches in the memory unit, using a pulse signal In the step of controlling the moving distance of the mover, the mover can move in unit pole pitch units (n × unit pole pitch, n is a natural number).

In addition, a method of calculating a unit pole pitch by multiplying a sinusoidal analog signal may be applied in various ways according to a required condition and a processing environment. For example, calculating the unit pole pitch may include generating an input analog signal by calculating a sinusoidal analog signal, and calculating a unit pole pitch corresponding to the input pulse signal by converting the input analog signal. have.

In the calculating of the unit pole pitch, the unit pole pitch may be separately divided and calculated for each length between the permanent magnets. In some cases, in the calculating of the unit pole pitch, the unit pole pitch may be calculated on the basis of the entire length of each permanent magnet.

According to another preferred embodiment of the present invention, a linear motor is provided on a mover to have a stator having a plurality of permanent magnets arranged alternately in polarity, a mover linearly driven by interaction with the stator, and a phase difference. A sine curve for the change of polarity of each permanent magnet by linearly detecting the magnetic flux according to the polarity of each permanent magnet through a plurality of linear hall sensors and a plurality of linear hall sensors that measure the phase of the mover by determining the polarity. A signal processor for generating an analog signal and converting a sinusoidal analog signal into a pulse signal, and a control unit for controlling the moving distance of the mover using a pulse signal.

In addition, the linear motor is initialized when the initial power is applied, and when the linear motor is initialized, the actuator is driven at a constant speed from a preset reference position, and the linear hole sensor is sequentially scanned for the length of the permanent magnets, and is output through the linear hall sensor. The unit pole pitch corresponding to the length between each permanent magnet is calculated by multiplying a sinusoidal analog signal, and the signal processing unit further includes a memory unit in which unit pole pitch information is stored, and the control unit comprises a unit pole. Shift in pitch units (n × unit pole pitch, n is a natural number).

According to the linear motor and the control method thereof according to the present invention, the structure and the manufacturing process can be simplified.

In particular, according to the present invention, by excluding a separate linear scale for sensing the moving amount of the mover with respect to the stator, by linearly sensing the magnetic flux according to the polarity of the permanent magnets, a sine curve for the change of polarity of each permanent magnet. A linear Hall sensor that generates an analog signal can be used to control the moving distance of the mover. Therefore, it is possible to eliminate the hassle of separately manufacturing a linear scale that must have high precision, and to reduce the production cost.

In addition, according to the present invention, since the unit pole pitch can be calculated using the signal detected through the linear hall sensor, and the mover can be driven based on the unit pole pitch, Drive error caused by this can be corrected. That is, due to the machining error and manufacturing error of the permanent magnet it is difficult to have a high precision of more than a predetermined interval between the permanent magnets. Furthermore, in order to maintain the high precision of the spacing between the permanent magnets, the production must be performed under a very precise atmosphere, which makes production difficult and increases production costs. However, according to the present invention, since the mover can be driven based on the unit pole pitch, even if the spacing between the permanent magnets is not maintained with high precision, the driving reliability and stability of the mover can be ensured.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited or limited by the embodiments. In describing the present invention, a detailed description of well-known functions or constructions may be omitted for clarity of the present invention.

1 is a view showing the structure of a linear motor according to the present invention, Figure 2 is a block diagram for explaining the configuration of a linear motor according to the present invention. 3 and 4 are block diagrams illustrating a method for controlling the linear motor according to the present invention, and FIGS. 5 and 6 are methods for controlling the linear motor according to the present invention. It is a figure for demonstrating the process.

Meanwhile, FIG. 7 is a diagram illustrating a process of calculating a unit pole pitch as a control method of a linear motor according to the present invention, and FIG. 8 illustrates a method of controlling a linear motor according to another embodiment of the present invention. Drawing.

As shown in FIG. 1 and FIG. 2, the linear motor according to the present invention includes a stator 10 and a mover 20 that linearly drives the stator 10, a linear hall sensor 30, and a signal processor 40. And a controller 50.

The stator 10 includes a stator plate 12 and a permanent magnet 14 having polarities alternately disposed on an upper surface of the stator plate 12.

The mover 20 is wound around the mover core 22 having a plurality of main teeth (not shown), and the main teeth 70 (for example, currents of three-phase (U, V, W)). It comprises a mover coil 24 for supplying a, by the interaction between the magnetic force generated in the movable coil 24 and the magnetic force of the permanent magnet 14 as a current is applied to the movable coil 24 Thrust of straight line is generated.

In addition, the edge portion of the chimney may be chamfered to reduce the detent force caused by the chimney of the mover 20. In some cases, in order to reduce the detent force caused by the attending physician, a structure for chamfering the corner of the permanent magnet instead of the attending doctor, or forming an extended tip at the corner of the attending doctor may be employed. The present invention is not limited or limited by the arrangement.

The linear hall sensor 30 is provided on the mover 20 so as to have a predetermined phase difference and is configured to sense the permanent magnet 14 of the malfunctioner 10. That is, the linear hall sensor 30 linearly detects the magnetic flux according to the polarity of each permanent magnet, unlike the conventional hall sensor that simply outputs a change in polarity of the magnet as an on / off signal. Generates a sine curve analog signal of the change in polarity of each permanent magnet.

The plurality of linear hall sensors 30 may be mounted on the mover 20 to have a phase difference of 90 degrees or a phase difference of 120 degrees. The linear hall sensor 30 may be mounted directly on the mover or may be mounted via a conventional connecting member, and the arrangement and mounting structure of the linear hall sensor 30 may be variously changed according to required conditions and design specifications. Can be.

The signal processor 40 is provided to process the signal sensed by the linear hall sensor 30 into a specific signal. That is, the signal processor 40 linearly detects the magnetic flux according to the polarity of each permanent magnet through the linear hall sensor 30 to generate a sine curve analog signal for the polarity change of each permanent magnet. The sine wave analog signal is converted into a pulse signal. In addition, the signal processor 40 includes a memory 42 for storing unit pole pitch information, which will be described later.

The controller 50 may control the driving (movement distance) of the mover 20 through a general servo driver using the pulse signal processed by the signal processor 40.

Hereinafter, a control method of the linear motor configured as described above will be described. In addition, the same or equivalent portions as those in the above-described configuration are denoted by the same or equivalent reference numerals, and a detailed description thereof will be omitted.

Referring to Figure 3, the control method of the linear motor according to the present invention, by sine wave for the polarity change of each permanent magnet by linearly sensing the magnetic flux according to the polarity of each permanent magnet through a plurality of linear Hall sensor 30 (Sine curve) generating an analog signal (S20), converting the sinusoidal analog signal into a pulse signal (S30), and controlling the moving distance of the mover 20 using the pulse signal (S40) ).

5 and 6, a plurality of linear Hall sensor 30 may be provided to have a phase difference of 90 degrees or a phase difference of 120 degrees, the number and phase difference of the linear Hall sensor 30 according to the required conditions and design specifications can be changed.

First, the magnetic flux according to the polarity of each permanent magnet is linearly (continuous) through the linear hall sensor 30 to generate a sine curve analog signal for a change in polarity of each permanent magnet. That is, as shown in FIG. 5, at this stage, two sinusoidal analog signals having a waveform shape having a 90 degree phase difference according to the magnetic flux of the permanent magnet may be generated through each linear hall sensor 30.

Next, the sine wave analog signal is converted into a pulse signal. That is, as shown in Figure 6, the sinusoidal analog signal may be converted into a pulse signal through a conventional conversion method.

Thereafter, the moving distance of the mover 20 may be controlled using the pulse signal. That is, the phase of the mover 20 can be detected by counting the crossing points of the detected two pulse signals A and B. FIG. In addition, an input analog signal may be generated by combining the detected two sinusoidal analog signals through a conventional calculation method, and converting the input analog signal into a pulse signal to convert an input pulse signal required for driving the mover 20. Can be calculated. Therefore, the movable distance of the mover 20 can be controlled by the number of input pulse signals. In addition, a combination of the two sinusoidal analog signals may be implemented by a conventional calculation method, and the present invention is not limited or limited by the type and characteristic of the calculation method.

As described above, in the present invention, the moving distance of the mover 20 may be controlled by using the linear hall sensor 30 that senses the permanent magnet without removing a separate linear scale. In other words, the phase of the mover for the permanent magnet is checked by using a general hall sensor that simply outputs a change in the polarity of the magnet as an on / off signal, and the moving amount of the mover is measured through a separate linear scale. Had to be detected. However, in the present invention, by using the sinusoidal analog signal detected by the linear hall sensor 30 to check the phase of the mover 20 for the permanent magnet, and also calculate the input pulse signal to move the mover 20 Can be controlled.

On the other hand, since the arrangement interval between the permanent magnets is difficult to have a certain level or higher precision due to the machining error and manufacturing error of the permanent magnet, the initialization step for correcting the drive error of the mover 20 due to the error of the permanent magnet ( S10) may be included.

That is, as shown in Figure 4, the initialization step (S10) of the linear motor, the step of placing the mover 20 at a predetermined reference position (S11), by driving the mover 20 at a constant speed Scanning the lengths between the permanent magnets in sequence with the linear hall sensor 30 (S13), multiplying the sinusoidal analog signals outputted through the linear hall sensor 30, and unit poles corresponding to the lengths between the permanent magnets. The method may include calculating a pitch (S15), and storing the calculated unit pole pitch in the memory unit 42 (S17).

First, after arranging the mover 20 at a predetermined reference position, the mover 20 is driven at a constant speed to sequentially scan the lengths between all permanent magnets.

While the permanent magnet is being scanned, the lengths L1, L2, L3 ... Ln between the permanent magnets may be detected by using a signal detected by the linear hall sensor 30, and the linear hall sensor 30 may be detected. Through this, a sine wave analog signal of a change in polarity of the permanent magnet may be output.

Next, multiplying the sine wave analog signal output as described above calculates a unit pole pitch corresponding to the length between each permanent magnet. The method of calculating the unit pole pitch by multiplying the sinusoidal analog signal may be applied in various ways according to a required condition and a processing environment. For example, the calculating of the unit pole pitch may include generating an input analog signal by calculating the sinusoidal analog signal, and calculating a unit pole pitch corresponding to an input pulse signal by converting the input analog signal. It may include.

In addition, in the step of calculating the unit pole pitch, unit pole pitch (P1, P2, P3 ...) may be calculated separately by the length of each permanent magnet. That is, as shown in Figure 7, when the length sections (L1, L2, L3 ... Ln) between each of the permanent magnets have different lengths, in each section (L1, L2, L3 ... Ln) The corresponding unit pole pitches P1, P2, P3 ... may be calculated to have different lengths (widths) (P1 ≠ P2 ≠ P3 ...), respectively.

In the above-described embodiment, the unit pole pitch is divided and calculated for each length of the permanent magnets separately. For example, the unit pole pitch P 'is an average value based on the entire length of each permanent magnet. It can be calculated as. That is, as shown in Figure 8, when the length sections (L1, L2, L3 ... Ln) between the permanent magnets have different lengths, in each section (L1, L2, L3 ... Ln) The corresponding unit pole pitches may be calculated to have the same length (width) P '.

Thereafter, the calculated unit pole pitch information may be stored in the memory unit 42, and the mover 20 may store unit pole pitch units n based on the unit pole pitch information stored in the memory unit 42. The travel distance can be controlled by the number of open poles, n = 1, 2, 3 ...).

On the other hand, in the step of calculating the unit pole pitch by multiplying the aforementioned sinusoidal analog signal, the sinusoidal analog signal may be multiplied in various bit units according to the required conditions and design specifications. The higher the multiplication of the sinusoidal analog signal, the higher the accuracy. However, the higher the multiplication of the sinusoidal analog signal, the higher the signal amount to be processed and the driving speed of the mover 20 may be lowered. It shall be possible to make appropriate provisions according to the required conditions and design specifications.

In addition, when the motor is driven, the mover may be driven based on the above-described unit pole pitch information. However, when the power is turned off or rebooted while the motor is driven, the motor may be driven after the above-described initialization step.

As described above, although described with reference to the preferred embodiment of the present invention, those skilled in the art various modifications and variations of the present invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

1 is a view showing the structure of a linear motor according to the present invention.

2 is a configuration diagram for explaining the configuration of a linear motor according to the present invention.

3 and 4 are block diagrams for explaining the control method of the linear motor according to the present invention.

5 and 6 are diagrams for explaining a process of processing a signal sensed by a linear hall sensor as a control method of a linear motor according to the present invention.

7 is a diagram illustrating a process of calculating a unit pole pitch as a control method of a linear motor according to the present invention.

8 is a view for explaining a method of controlling a linear motor according to another embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

10: stator 12: stator plate

14: permanent magnet 20: mover

22: mover core 24: mover coil

30: linear hall sensor 40: signal processing unit

42: memory unit 50: control unit

Claims (9)

A stator having a plurality of permanent magnets arranged alternately in polarity, a mover linearly driven by interaction with the stator, and provided on the mover to have a phase difference to measure the phase of the mover through polarity determination In the control method of the linear motor including a plurality of linear hall sensor, to control the moving distance of the mover without a separate scale, Initializing the linear motor when initial power is applied; Generating a sine curve analog signal corresponding to a change in polarity of each permanent magnet by linearly sensing the magnetic flux according to the polarity of each permanent magnet through the plurality of linear hall sensors; Converting the sinusoidal analog signal into a pulse signal; And Controlling the moving distance of the mover using the pulse signal; Initializing the linear motor, Arranging the mover at a predetermined reference position, driving the mover at a constant speed to sequentially scan the lengths of the permanent magnets with the linear hole sensor, and multiplying the sinusoidal analog signal output through the linear hall sensor; multiplying) to calculate a unit pole pitch corresponding to the length between each permanent magnet, and storing the calculated unit pole pitch in a memory unit, And controlling the moving distance of the mover using the pulse signal, wherein the mover moves in the unit pole pitch unit (n × unit pole pitch, n is a natural number). delete The method of claim 1, Computing the unit pole pitch, Generating an input analog signal by calculating the sinusoidal analog signal; And Calculating the unit pole pitch corresponding to the input pulse signal by converting the input analog signal. The method of claim 1, The unit pole pitch control method of the linear motor, characterized in that calculated separately for each length between the permanent magnet. The method of claim 1, The unit pole pitch is calculated on the basis of the entire length between each permanent magnet on the average control method for a linear motor. A stator having a plurality of permanent magnets arranged alternately in polarity; A mover linearly driven by interaction with the stator; A plurality of linear hall sensors provided on the mover to have a phase difference to measure phases of the mover through polarity determination; Linearly detect the magnetic flux according to the polarity of each permanent magnet through the plurality of linear Hall sensor to generate a sine curve analog signal for the change of polarity of each permanent magnet, and the sinusoidal analog signal to a pulse signal Signal processing unit for converting to; And A control unit for controlling the moving distance of the mover by using the pulse signal; The linear motor is initialized when the initial power is applied, When the linear motor is initialized, the mover is driven at a predetermined speed from a preset reference position to sequentially scan the length between the permanent magnets with the linear hole sensor, and multiplying the sinusoidal analog signal output through the linear hall sensor. The unit pole pitch corresponding to the length between each permanent magnet is calculated, The signal processor further includes a memory unit in which the unit pole pitch information is stored. And the control unit moves the mover to the unit pole pitch unit (n × unit pole pitch, n is a natural number). delete The method of claim 6, The unit pole pitch is a linear motor, characterized in that calculated separately for each length between the permanent magnets. The method of claim 6, The unit pole pitch is calculated on the basis of the total length between each permanent magnet on the linear motor.

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