JPH03155396A - Motor controller - Google Patents

Abstract

PURPOSE:To reduce a wiring space, to delete a logic circuit, and to switch a driving system without erroneous step by inputting a signal of an encoder to an external controller, knowing an exciting pattern at the time of driving in a closed loop and switching a closed loop drive to an open loop drive. CONSTITUTION:In order to first know an exciting pattern of a closed loop drive, an external controller 4 reads the value of an inner counter 41 to know the advanced number of pulses of a motor 1. When the value is divided by 6 of the number of pulses per one step, the number of steps advanced to the present is known. Accordingly, after the motor 1 is reset, if an initial exciting pattern is obtained, a closed loop driving exciting pattern at the time of switching is known. Then, the controller 4 outputs an exciting pattern of an open loop drive matched to the closed loop exciting pattern, and simultaneously applies the output of a signal converter 5 to open loop drive signals 113-116 by a switching signal 117.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a motor control device suitable for office automation equipment such as personal computers and printers for word processors.

[Prior Art] Conventionally, a drive system that switches between closed-loop drive and open-loop drive is known as a motor control device suitable for office automation equipment. and a counting means for counting the number of detected parts of the encoder as the rotor rotates at a predetermined location on the stator side, and when the count value of the counting means matches a predetermined value, electricity is supplied to the coil of the stator. It is possible to switch between closed-loop drive, which performs switching, and open-loop drive, which performs normal energization switching of a stepping motor.

In that case, it is difficult to smoothly switch from closed-loop drive to open-loop drive because the positional relationship between the rotor magnetic poles and stator magnetic poles is different when switching the energization to the coils, and there are multiple excitation bangs (4 bangs for 1-phase excitation). It is necessary that the excitation patterns before and after switching are the same or advance in the direction of rotation of the motor.

Generation of an excitation signal for such open loop (step drive) and switching between both drives are performed by an external control device.

[Problems to be Solved by the Invention] For this reason, conventionally, an external control device monitors the excitation pattern of the closed-loop drive and outputs a signal for inter-loop drive (step drive) in accordance with the excitation pattern. It was necessary to extend a long signal line for the excitation signal from the motor drive signal generator that generates the excitation pattern to the external control device. For example, a two-phase PM stepping motor has four excitation phases, so it is necessary to extend four signal lines to the external control device, and if it becomes a multi-phase motor, the number of lines will increase significantly. . Therefore, the signal line pattern on the board becomes complicated, and if the external control device and the motor drive circuit are not on the same board, there are problems in that a large number of signal cables are required.

The object of the present invention is to solve the above-mentioned drawbacks, and to reduce the number of images and to enable smooth switching between closed-loop drive and open-loop drive without any missteps.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a rotational position detection means for detecting the rotational position of a step motor, and a rotational position detection means for detecting the rotational position of the step motor, and a method for detecting the step motor based on a detection signal from the rotational position detection means. a motor drive signal generator that generates an excitation signal for closed loop drive; and a motor drive signal generator that generates an excitation signal for open loop drive of the step motor based on the detection signal from the rotational position detection means; It is equipped with an external control device that outputs a switching signal for switching open-loop drive, and a switching means for switching the drive signal.

[Example] A first embodiment of the present invention will be described below with reference to the drawings.

Figure 1 shows the block configuration of the motor control circuit.
1 is a step motor, 2 is an encoder that detects the rotation of the step motor 1, and 3 is a built-in counter 31 that counts 100 output pulses from the encoder 2. When the counted value matches a predetermined value, the motor drive excitation pattern is activated. A motor drive signal generator 4 outputs excitation signals 101 to 104 for switching, and 4 has a built-in counter 4I that counts output pulses from the encoder 2, and includes a reset signal 119 for the counter 3I, a drive switching signal 117, and a speed control signal 118. and an external control device 5 that outputs step drive excitation signals 113 to 116;
1 to 104 and step drive excitation signals 113 to 116 to the switching motor driver circuit 6.

2A and 2B specifically show the motor 1 shown in FIG. 1, where 10 indicates the rotor 11, and 12
A and 12B are stators, 13A and 13B are coils, and an encoder detection disk 14 is coaxially mounted on the rotor shaft.
However, a detection unit 15 is also attached to the stator side. Thereby, the rotational position of the motor 1 can be detected by counting the output pulses from the encoder 2, which includes the detection disk 14 and the detection unit 15.

Since this step motor 1 uses a two-phase step motor, excitation switching is performed in a one-phase pattern 48 times per rotation of the rotor, and the number of output pulses from the encoder 2 is 288 per rotation. shall be. Therefore, since the rotor 10 rotates by an equal angle for each excitation pattern, if this rotation angle is one step, the number of pulses output from the encoder 2 for each step is 2.
88/4B=6. Therefore, if the excitation is switched every time six output pulses from the encoder 2 are counted, the rotor can be rotated at equal intervals.

However, in this case, the magnetic poles of the rotor 10 and the stator 12A,
Since the motor 1 will not rotate unless it is maintained in a predetermined relative positional relationship with the magnetic poles 12B, relative alignment between the rotor magnetic poles and the stator magnetic poles is required as an initial operation. Therefore, in reality, the counter 31 in the motor drive signal generator 3 is reset to a predetermined value while a certain predetermined phase is excited, and then the pulses from the encoder 2 are counted by the counter, and the predetermined value (main In the example, 6 pulses)
The excitation should be changed every other time. In this way, excitation switching can be performed when the relative positions of the rotor magnetic poles and the stator magnetic poles reach a certain relationship. For example, in the case of one-phase excitation, a ring counter capable of counting 24 counts for one torque cycle, that is, four steps, is used as the counter. If the excitation switching count values in this case are 6.12.18 and 0, an excitation waveform as shown in FIG. 3 is obtained.

Next, the motor control operation of the above configuration will be explained.

First, the closed loop drive of the motor 1 will be described.

Counter 3 of motor drive signal generator 3. is encoder 2
100 output pulses are counted, and when the counted value matches a predetermined value, the motor drive excitation pattern is switched and excitation signals 101 to 104 are output. The next-stage signal switch 5 outputs excitation signals 101 to 104 and step drive excitation signals 113 to 116 output by the external control device 1 to the switching motor driver circuit 6 in response to the drive switching signal 117 of the external control device 4 . The motor driver circuit 6 controls the coils 13A and 1 of the motor 1 according to the excitation signals 105 to 108.
Supply current to 3B and rotate motor l. Encoder 2 outputs output pulses 100 as motor 1 rotates.

Next, switching between closed-loop drive and open-loop drive will be described. Closed-loop drive to open-loop drive (step drive)
When switching to , the first excitation button of the step drive must be the same as the last excitation pattern of the closed loop. need to know the status of So encoder 2
100 output pulses are input to the external control device 4,
The external control device 4 counts 100 output pulses from the encoder 2 using an internal counter 41 . This counter 4 does not have to be a 24-count counter like the counter 31 inside the motor drive signal generator 3 described above, but may be a binary 16-bit serial counter for detecting the rotation amount of the motor, for example. Also good. However, it is necessary to reset the counter 41 at the same time as resetting the counter 3I inside the signal generator 3, or to store the counter value when the counter 3I inside the signal generator 3 is reset. This is to synchronize the two counters, and is necessary to correctly know the excitation pattern of the closed-loop drive at the time of drive switching. and,
For the operation when switching drives, first of all, the excitation pattern of the closed-loop drive is known. For this purpose, the external control device 4 reads the value of the internal counter 4I and learns the number of pulses the motor has advanced.

Divide that value by 6, which is the number of pulses per step, and you get
You can see the number of steps you have taken so far. Therefore, if the first excitation button after resetting the motor is known, the closed loop drive excitation pattern at the time of switching can be known. Next, the external control device 4 outputs an excitation button for open-loop drive (step drive) matching the closed-loop drive excitation pattern, and at the same time outputs a switching signal 1.
17, the output of the signal switch 5 is made into an open loop drive signal 113-116. FIG. 4 shows an example of an excitation button change when switching from closed loop drive to interloop drive.

Next, a second embodiment of the present invention will be explained with reference to FIG.
Components that are the same as those in FIG. 1 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

FIG. 5 is a block diagram showing a second embodiment of the present invention. The feature of this embodiment lies in the configuration of the counter in the external control device 4, in which numeral 42 in FIG. 5 is a prescale counter;
is a counting counter. The output pulses from the encoder 2 that are input to the external control device 4 are first counted by the briscale counter 42 . The briscale counter 42 counts six pulses, which is the number of pulses from the encoder 2 per step, and generates a carry signal 120 when six pulses are exceeded. This signal is counted by the counting counter 4I. Therefore, by reading the value of the internal counting counter 4, the external control device 4 can know the number of pulses in progress and know the closed loop drive signal pattern at the time of switching. The subsequent processing may be performed in the same manner as in the first embodiment.

[Effects of the invention] As explained above, the number of wiring lines and wiring space can be reduced by inputting the encoder signal to the external control device, knowing the excitation button during closed-loop driving, and switching from closed-loop driving to open-loop driving. , the number of logic circuits can be reduced, and the drive system can be switched smoothly without any missteps, and the optimal drive system can be selected depending on the usage condition of the motor.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram of a motor control circuit showing a first embodiment of the present invention, FIG. 2A is a detailed view of the motor shown in FIG. 1, and FIG. 2B is a sectional view of the motor shown in FIG. 2A. Figure 3 is an excitation signal waveform diagram of the circuit shown in Figure 1 in the closed-loop drive state, and Figure 4 shows the changes in the excitation phases of - and - when the circuit in Figure 1 is switched from closed-loop to open-loop drive. Figure 5
The figure is a block configuration diagram of a motor control circuit showing a second embodiment of the present invention. 1... Motor 2... Encoder 31... Force, counter 3... Motor drive signal generator 4, -...
Counter 4...External control device 5...Signal switch
6... Sota driver circuit [3

Claims (2)

[Claims] (1) a rotational position detection means for detecting the rotational position of the step motor; a motor drive signal generator for generating an excitation signal for driving the stepper motor in a closed loop based on a detection signal from the rotational position detection means; An external control device that generates an excitation signal for open-loop driving the step motor based on a detection signal from the position detection means and outputs a switching signal for switching between the closed-loop drive and the open-loop drive, and a drive signal. A motor control device comprising a switching means for switching. (2) The external control device has a counter therein and counts signals from the rotational position detection means, and when switching from the closed-loop drive to the open-loop drive is performed, the external control device receives the same excitation signal or a phase-advanced excitation signal. 2. The motor control device according to claim 1, wherein the motor control device is capable of generating.