JP2009077467A - Micro-step drive method of stepping motor and indicating device using the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a micro-step drive method of a stepping motor which is achieved in fine (smooth) motion by a simple circuit constitution, since rotation is controlled by obtaining a PWM carrier according to the result acquired by the calculation processing a control unit (CPU) equipped generally on the basis of rotational speed and a resolution of a control angle of the stepping motor which is made constant irrespective of the rotational speed, and an indicating device using the method. <P>SOLUTION: The micro-step drive method of the stepping motor 115 comprises a process for converting an input signal into the rotational speed, and a process for setting the PWM carrier (cycle) 130 on the basis of the rotational speed and the resolution of the control angle 121 which is made constant irrespective of the rotational speed. The fine (smooth) rotation can be controlled by simple operation processing. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a stepping motor micro-step driving method using a PWM signal and an instruction device using the method.

In the use of a general stepping motor, the resolution of the control angle, that is, the stepping motor rotation angle that proceeds in accordance with one input pulse has two types, full step and half step, and the leading angle R per step at that time is (Expression 1)

  Here, the number of steps in one cycle is the number until the excitation pattern of the number of steps of the stepping motor becomes the same. FIG. 9 is an explanatory diagram showing the configuration of the stepping motor, and FIG. 10 is an explanatory diagram showing the resolution according to the driving method of the stepping motor.

  For example, in the case of a two-phase stepping motor with 25 rotor teeth (number of pole pairs) shown in FIG. 9 and full-step drive by the unipolar shown in FIG. 10, the number of steps in one cycle is 4, so the control angle resolution is 3.6 degrees / step. In the case of half-step driving, the number of steps in one cycle is 8, so that the resolution of the control angle is 1.8 degrees / step.

  And in the general usage method of a stepping motor, it can be rotated by controlling the electric current sent to each coil | winding (not shown) of a stator. However, this method can be realized with a simple and small control circuit, but on the other hand, the resolution of the control angle is not smaller than 1.8 degrees / step. One of the methods for compensating for the drawbacks of the above two-phase stepping motor is a micro-step driving method.

  FIG. 11 is an explanatory view showing the operation of a conventional stepping motor using a micro-step driving method.

  As shown in FIG. 10, this micro-step drive system is one of the techniques for controlling the fine position, and can change the energization current to the coil stepwise to stop the rotor at a position corresponding to the energization current. .

  FIG. 12 is a circuit diagram showing a configuration of a conventional microstep driving method of a stepping motor.

  The conventional microstep driving method of a stepping motor changes the current passed through each winding (not shown) of the stepping motor into a sine wave shape and a cosine wave shape based on the sine wave current setting data and the cosine wave current setting data, This is a micro-step driving method in which the rotation of the rotor 3 is controlled with a resolution of a control angle corresponding to the number of divisions of the current setting data. A plurality of types of current setting data having different division numbers are prepared and the stepping motor 1 is set. When the set maximum speed is higher than the maximum speed, the current setting data with a small number of divisions is selected, and when the set maximum speed is low, the current setting data with a large number of divisions is selected.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
Japanese Patent Publication No. 8-8796

  However, in the above-described conventional configuration, a plurality of types of current setting data having different division numbers are prepared for microstep driving of the stepping motor, and when carrying out finer control, current setting data having many different division numbers. And a plurality of storage units are required in the circuit configuration, and there is a problem that it cannot be realized with a simple and small control circuit.

  The present invention solves the above-described problem, and performs calculation processing by a control unit (CPU) that is normally equipped based on the rotation speed and the resolution of the control angle of the stepping motor that is constant regardless of the rotation speed, Since the PWM carrier is obtained based on the obtained results and the rotation control is performed, a plurality of different current setting data is not required, so that a memory (memory) as a new circuit configuration is not required and a simple circuit configuration is finer. It is an object of the present invention to provide a microstep driving method of a stepping motor capable of realizing a smooth (smooth) movement and an indicating device using the same.

In order to solve this object, the present invention has the following configuration.
According to a first aspect of the present invention, in a microstep driving method of a stepping motor using a PWM signal, the step of detecting the rotational speed of the stepping motor from an input signal, the rotational speed, and the stepping motor A step of setting a PWM carrier (cycle) based on a resolution of a constant control angle regardless of the rotation speed, and a stepping motor micro-step driving method, and a simple arithmetic processing of a control circuit normally provided This makes it possible to control fine (smooth) rotation.
According to a second aspect of the present invention, in the microstep driving method of a stepping motor using a PWM signal, a step of detecting the rotational speed of the stepping motor from an input signal, and at least two rotations at which the rotational speed is preset Determining one of the speed ranges and associating one rotational speed with the determined rotational speed range; and the resolution of the control angle that is constant regardless of the associated rotational speed and the rotational speed of the stepping motor; And a step of setting the PWM carrier (cycle) based on the above, and a stepping motor micro-step driving method comprising: (Smooth) rotation can be controlled.

  According to a third aspect of the present invention, in the pointing device including a stepping motor that is micro-step driven by a PWM signal and a position detection unit that detects a reference position, the position detection unit outputs a signal obtained by passing through a light shielding plate. An optical element for obtaining the reference position based on the detection means for detecting the rotational speed of the stepping motor from an input signal, the rotational speed, and a resolution of a constant control angle irrespective of the rotational speed of the stepping motor; And an arithmetic processing means for setting a PWM carrier (cycle) based on the above, and can control finer (smooth) rotation with a simple and small control circuit that is normally equipped .

  According to a fourth aspect of the present invention, in the pointing device including a stepping motor that is micro-step driven by a PWM signal and a position detection unit that detects a reference position, the position detection unit outputs a signal obtained by passing through a light shielding plate. An optical element for obtaining the reference position based on the detection means for detecting the rotation speed of the stepping motor from an input signal, and determining at least one of at least two rotation speed ranges in which the rotation speed is preset; PWM carrier based on division / association means for associating one rotational speed with the determined rotational speed range, the associated rotational speed, and a resolution of a constant control angle regardless of the rotational speed of the stepping motor And a processing unit for setting (cycle), and a simple and small control circuit that is normally equipped Kana can be controlled (smooth) rotation.

  As described above, the present invention relates to the step of detecting the rotation speed of the stepping motor from the input signal, the rotation speed, and the rotation speed of the stepping motor in the microstep driving method of the stepping motor using the PWM signal. A stepping motor micro-step driving method including a step of setting a PWM carrier (cycle) based on a constant control angle resolution, and fine (smooth) by a simple arithmetic processing of a control circuit normally provided. Rotation can be controlled.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  (Embodiment 1)

  First, the configuration of the pointing device using the microstep driving method according to Embodiment 1 of the present invention will be described. Here, the position detection means is a position detection section, the detection means for detecting the rotational speed is a speed detection section, the control means is a control section, and the division / association means is a division / association section.

  1 is a block diagram showing the configuration of an indicating device using the microstep driving method according to Embodiment 1 of the present invention, FIG. 3 is a plan view showing the configuration of a meter (indicating unit), and FIG. 4 is the configuration of a mechanism unit. It is sectional drawing shown.

  1 includes a digital input terminal 111a and an analog input terminal 111b. The control unit 113 includes a speed detection unit 112, an A / D converter 119, and an arithmetic processing unit 118, and a drive circuit unit 114. The position detection unit 117 includes a stepping motor 115 and a meter (instruction unit) 116.

  Hereinafter, the configuration of the microstep driving method according to Embodiment 1 of the present invention will be described in detail.

  The indicating device 110 includes an input terminal 111a for inputting a digital signal output from a sensor (not shown), a marine equipment or the like, and an input terminal 111b for inputting an analog signal, and an input signal input to the digital input terminal 111a or A speed detector 112 that detects a rotational speed from a digital signal input to the analog input terminal 111b and converted by the digital converter 119, and a signal including information on the rotational speed from the speed detector 112 and a preset rotation Calculation processing with a resolution of a constant control angle irrespective of the speed, and conversion processing into a microstep drive PWM signal based on the result, and stepping the microstep drive PWM signal from the calculation processing unit 118 Drive circuit unit 114 that converts the drive signal of the motor 115, drive A stepping motor 115 which rotates to indicate the predetermined value in response to a drive signal from the road section 114, and a meter (instruction unit) 116 indicating the predetermined value by the rotation of the stepping motor 115.

  3 and FIG. 4, the position detection unit 117 includes a display board 123 on which a scale is displayed, a pointer 124 disposed on the display board 123 and fixed to the rotation shaft 125, and the display board 123. The photo interrupter 127 is disposed below and outputs a signal corresponding to light shielding. The light interrupting plate 126 is disposed below the display plate 123 and is fixed to the rotating shaft 125 of the stepping motor 115 and shields the photo interrupter 127 from light. Here, the photo interrupter 127 is configured to output a rectangular wave signal generated by comparing the output signal 129 corresponding to the light shielding by the light shielding plate 126 and the reference voltage to the arithmetic processing unit 118 of the control unit 113.

  Next, the operation of the pointing device using the microstep driving method according to Embodiment 1 of the present invention will be described with reference to the drawings.

  FIG. 5 is an explanatory view showing the setting operation of the reference position by the photo interrupter, and FIG. 6 is an explanatory view showing the output signal of the photo interrupter.

  The indicating device 10 rotates a stepping motor 115 in accordance with a signal from a NMEA2000 (National Marine Electronics Association) for exchanging data between marine control devices, a signal from a sensor (not shown), etc. ) 116 shows a predetermined value.

  First, a reference position setting operation necessary for the pointing device 110 using the stepping motor 115 will be described.

  When the instruction device 110 is turned on, the position detection unit 117 performs an operation of setting a reference position.

  As shown in FIG. 5, the light-shielding plate 126 fixed to the rotation shaft 125 of the stepping motor 115 rotates once at a constant speed by rotating clockwise or counterclockwise. For example, when the light shielding plate 126 is rotated by right rotation, the opening 128 of the photo interrupter 127 is gradually shielded by the light shielding plate 126 from time t1 to time t3, and the entire opening 128 is shielded from time t3 to time t4. The light is shielded. Then, from time t4 to t6, the opening 128 of the photo interrupter 127 is gradually opened, and the entire opening 126 is opened at time t6.

  In this state, the photo interrupter 127 has a maximum voltage level of the output signal 129 of the photo interrupter 127 from time t1 to t3 during one rotation of the light shielding plate 126 fixed to the stepping motor 115 as shown in FIG. The voltage level gradually decreases, and the minimum voltage level state is maintained from time t3 to t4.

  From time t4 to t6, the voltage level of the output signal 129 of the photo interrupter 127 gradually increases, and again reaches the maximum voltage level at time t6. Then, in the position detection unit 117 having a voltage comparator (not shown), the output signal 129 is compared with the reference voltage, thereby generating a rectangular wave signal in which the opening 128 is shielded by the light shielding plate 126 to generate a control unit. The result is output to the arithmetic processing unit 118. The rectangular wave signal is counted by the arithmetic processing unit 118 using the clock signal sufficiently smaller than the rectangular wave signal time width, and the time width of the generated rectangular wave signal is counted. The reference position T is detected. Here, the reference position T is a zero point of the scale displayed on the display board 123 of the meter (instruction unit) 116 or a predetermined reference point.

  When the reference position T is set by the above operation, the pointer 124 indicates a predetermined value when there is no input. Generally, it indicates a zero point.

  Next, the operation of the microstep driving method according to the first embodiment of the present invention will be described with reference to FIG. 1, FIG. 7, and FIG.

  7A to 7D are explanatory diagrams showing the operation of the microstep driving method according to Embodiment 1 of the present invention, and FIGS. 8A to 8K show the resolution of the control angle of the microstep driving method. It is explanatory drawing.

  When a digital signal from a marine control device such as NMEA 2000 is input to the input device 111a in the pointing device 110 shown in FIG. 1, the speed detection unit 112 detects the rotational speed with respect to the input digital signal. Then, a signal including information on the rotation speed detected by the speed detection unit 118 is input to the arithmetic processing unit 112. The arithmetic processing unit 118 performs arithmetic processing on the resolution of the control angle 121 that is constant regardless of a preset rotational speed and a signal including information on the rotational speed, and based on the result of the arithmetic processing, PWM of microstep driving is performed. Convert to signal 122.

  On the other hand, the analog signal input to the analog input terminal 111b is converted into a digital signal by the A / D converter 119, output to the speed detection unit 112, and a similar operation is performed by the arithmetic processing unit 118 from the speed detection unit 112. To be implemented.

  Here, as shown in FIGS. 7A to 7D, the PWM signal 122 is a PWM carrier (period) based on the resolution of one preset control angle 121 regardless of the rotational speed of the input signal. 130 is determined. As a result, the PWM carriers (periods) 130 of the PWM signals 122 having different rotation speeds, for example, 360 degrees / sec and 180 degrees / sec, are 1 to 2 of T1 to 2T1, but the duty ratio and the PWM frequency are the same. Note that the resolution of one preset control angle 121 is determined from the same viewpoint as the period of the vertical synchronizing signal of the TV. For example, the period of the vertical synchronizing signal of a TV in the PAL system is about 40 msec, and an originally stationary image appears to move due to an afterimage phenomenon of the eyes. Paying attention to this point of view, this effect can be utilized up to about 0.4 degrees (15 points / sec) for a low speed rotation of about 6 degrees / sec. However, in the case of low-speed rotation, finer (smooth) movement of the pointer 124 naturally becomes finer (smooth) movement if the resolution of the control angle 121 is reduced, but the PWM frequency increases, and the control unit 113 Since the clock also rises, a highly responsive device is required, and the pointing device 110 becomes expensive. Here, as shown in FIGS. 8A to 8K, the PWM frequency is a clock signal for generating the PWM signal 122, and one bit corresponds to the resolution of the control angle 121. In general, the PWM frequency is preferably several hundred kHz or less.

  The relationship among the rotational speed R, the PWM carrier (cycle) Tk, the control angle resolution An, the PWM frequency fp, and the basic step angle As is

        Tk = An / R

fp = (Tk / (As / An))
It is represented by

The resolution of the control angle 121 and the PWM frequency with respect to the rotational speed of the input signal of the general PWM signal 122 are shown in Table 1. Here, the basic step angle is 18 degrees.

  As shown in (Table 1), when the PWM carrier (period) 130 is constant with respect to the change in the rotational speed R of the input signal, the resolution of the control angle 121 becomes higher as the rotational speed becomes lower. And the pointing device 110 is also expensive.

Next, Table 2 shows the resolution of the control angle 121 and the PWM frequency with respect to the rotational speed R of the input signal of the PWM signal 122 by the microstep driving method according to the first embodiment of the present invention.
Again, the basic step angle was 18 degrees.

  As shown in (Table 2), the resolution of the control angle 121 is set in advance to 0.36 degrees that rotate finely (smoothly) even at a low rotational speed regardless of the rotational speed R of the input signal. By setting the PWM carrier (cycle) 130, a finer (smooth) movement can be realized even during low-speed rotation, and the PWM frequency can be stopped at a low frequency that can be configured with an inexpensive circuit.

  Then, the drive circuit unit 114 converts the PWM signal 130 generated by the arithmetic processing unit 118 of the control unit 113 into a drive signal for the stepping motor 115 and drives the stepping motor 115. As a result, a value corresponding to the PWM signal 130 is indicated on the scale on the display plate 123 of the meter (instruction unit) 116 by the pointer 124 fixed to the rotating shaft 125.

As described above, the control unit (CPU) 113 that is normally equipped performs arithmetic processing based on the rotation speed and the resolution of the control angle 121 of the stepping motor 115 that is constant regardless of the rotation speed, and based on the obtained result. Since a plurality of different current setting data is not required because the PWM carrier 130 is obtained and the rotation is controlled, a smooth movement can be realized with a simple circuit configuration without requiring a memory (memory) as a new circuit configuration. Can do.
(Embodiment 2)

  Next, an instruction device using the microstep driving method according to Embodiment 2 of the present invention will be described.

  Hereinafter, the configuration of the pointing device using the microstep driving method according to Embodiment 2 of the present invention will be described with reference to the drawings.

  FIG. 2 is a block diagram showing the configuration of the pointing device according to the microstep driving method in Embodiment 2 of the present invention. Note that the description of the same configuration as that of the first embodiment is omitted.

  The configuration different from that of the first embodiment is that one of at least two rotation speed ranges in which rotation speed information from the speed detection unit 112 is set in advance is determined, and one rotation speed is set in the determined rotation speed range. The division / association unit 120 to be associated is added.

  The division / association unit 120 eliminates the need for a calculation process for obtaining the PWM carrier (cycle) 130 in accordance with the rotation speed of the input signal.

  The operation of the pointing device using the microstep driving method in the second embodiment will be described below.

  The division / association unit 120 shown in FIG. 2 previously divides and sets the rotation speed into at least two ranges, and one rotation speed is associated with each divided rotation speed range. Then, it is determined which range of the divided rotation speed range the rotation speed information output from the speed detection unit 112 is included, and one rotation speed corresponding to the determined rotation speed range is set in advance. The PWM carrier (cycle) 130 is associated with the resolution of the control angle 121 without performing arithmetic processing, and the arithmetic processing unit 118 generates the PWM signal 122 from these pieces of information.

For example, the resolution of the control angle 121 and the PWM frequency with respect to the rotational speed R of the input signal of the PWM signal 122 by the microstep driving method according to the second embodiment in which the input rotational speed R is divided into three are shown in Table 3. Again, the basic step angle was 18 degrees.

  The rotational speed R input as shown in Table 3 is divided into R> 36 degrees / sec, 6 degrees / sec ≦ R ≦ 36 degrees / sec, and R <6 degrees / sec, and R> 36 degrees / sec. sec is associated with 360 degrees / sec, 6 degrees / sec ≦ R ≦ 36 degrees / sec is associated with 36 degrees / sec, and R <6 degrees / sec is associated with 6 degrees / sec. When the resolution of the control angle 121 is 0.36 degrees, the PWM carrier (period) 130 is 1 ms, 10 ms, and 60 ms, the PWM frequency is 50 kHz, and the condition of the PWM signal 122 is obtained without requiring arithmetic processing. A PWM signal 122 is generated by the processing unit 118. Hereinafter, it is the same as that of Embodiment 1, and description is abbreviate | omitted.

  As described above, the rotational speed R is divided into at least two ranges in advance, and one rotational speed is associated with each of the divided rotational speeds R, whereby the rotational speed information input from the speed detector 112 is divided. It is determined which range of the determined rotational speed range is included, and the PWM signal is not calculated by one rotational speed corresponding to the determined rotational speed range and the resolution of the control angle 121 set in advance. 122 can be generated.

  Based on the rotation speed and the resolution of the control angle of the stepping motor that is constant regardless of the rotation speed, the control unit (CPU) that is normally equipped performs arithmetic processing, and based on the obtained result, the PWM carrier is obtained and rotated. Since the control is performed, a finer (smooth) movement can be realized with a simple circuit configuration, which is effective for an indicating device used in automobiles, measuring instruments, marine equipments, and the like.

The block diagram which shows the structure of the instruction | indication apparatus using the microstep drive method in Embodiment 1 of this invention. The block diagram which shows the structure of the instruction | indication apparatus by the micro step drive method in Embodiment 2 of this invention Plan view showing the configuration of the meter (instruction unit) Sectional view showing the configuration of the working part Explanatory drawing showing the setting operation of the reference position by the photo interrupter Explanatory diagram showing the output signal of the photo interrupter (A)-(d) is explanatory drawing which shows the micro step drive method of this invention. (A)-(k) is explanatory drawing which shows the resolution of the control angle of a microstep drive method Explanatory drawing showing the configuration of the stepping motor (A), (B) is explanatory drawing which shows the resolution by the drive method of a stepping motor Explanatory drawing which shows operation | movement of the micro step drive method of the conventional stepping motor. Circuit diagram showing configuration of conventional microstep driving method

Explanation of symbols

110 instruction device 111a digital input terminal 111b analog input terminal 112 speed detection unit 113 control unit 114 drive circuit unit 115 stepping motor 116 meter (instruction unit)
117 Position detection unit 118 Arithmetic processing unit 119 A / D converter 120 Division / association unit 121 Control angle 122 PWM signal 123 Display plate 124 Pointer 125 Rotating shaft 126 Shading plate 127 Photo interrupter 128 Opening portion 129 Output signal 130 PWM carrier ( period)

Claims (4)

In a microstep driving method of a stepping motor using a PWM signal,
Detecting the rotation speed of the stepping motor from an input signal;
Setting a PWM carrier (period) based on the rotational speed and the resolution of a constant control angle regardless of the rotational speed of the stepping motor;
A micro-step driving method for a stepping motor comprising: In a microstep driving method of a stepping motor using a PWM signal,
Detecting the rotation speed of the stepping motor from an input signal;
Determining one of at least two rotation speed ranges in which the rotation speed is preset;
Associating one rotational speed with the determined rotational speed range;
Setting a PWM carrier (cycle) based on the associated rotational speed and the resolution of the control angle that is constant regardless of the rotational speed of the stepping motor;
A micro-step driving method for a stepping motor comprising: In a pointing device including a stepping motor that performs microstep driving by a PWM signal and a position detection unit that detects a reference position,
The position detection means has an optical element for obtaining the reference position based on a signal obtained by passing through a light shielding plate,
Detecting means for detecting the rotation speed of the stepping motor from an input signal;
Control means for setting the PWM carrier (cycle) based on the rotational speed and the resolution of the control angle that is constant regardless of the rotational speed of the stepping motor;
Indicating device. In a pointing device including a stepping motor that performs microstep driving by a PWM signal and a position detection unit that detects a reference position,
The position detection means has an optical element for obtaining the reference position based on a signal obtained by passing through a light shielding plate,
Detecting means for detecting the rotation speed of the stepping motor from an input signal;
Dividing / associating means for determining any one of at least two rotation speed ranges set in advance, and associating one rotation speed with the determined rotation speed range;
Control means for setting the PWM carrier (cycle) based on the associated rotational speed and the resolution of the control angle that is constant regardless of the rotational speed of the stepping motor;
Indicating device.

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