JP5770701B2 - Stepping motor drive control device - Google Patents

Description

  The present invention relates to a drive control device for a stepping motor in which a motor control unit acquires position information and speed information of a rotor based on detection signals from a rotation detection unit, performs feedback control, and outputs a motor current to a motor coil.

  As a stepping motor drive control device, for example, one disclosed in Japanese Patent No. 4979466 is known. This motor drive control device starts the stepping motor with micro step drive, and when the rotor speed becomes medium to high speed, it switches to speed servo drive by the drive switch, and when approaching the stop position, the motor decelerates and At that time, the drive switching machine switches to microstep driving and stops (see Patent Document 1).

JP 2010-28949 A

The above-described stepping motor drive control device performs micro-step driving in the low speed region to perform highly accurate positioning, and performs speed servo control in which a motor current corresponding to the required torque is supplied in the other medium and high speed regions. However, since the drive control is performed in a single drive mode, the scene where the stepping motor is used is limited. Also, stepping motors may cause constant current to flow constantly even when driving is stopped, resulting in increased power consumption or hunting, and insufficient rotational torque in the high-speed rotation region where the motor rotation is stable. The stepping motor cannot always be used in a manner that meets the needs of the user.
Therefore, according to the situation of use, constant current control (step drive) of a stepping motor with high positioning accuracy in a low speed range and motor current control (power saving drive) of a servo motor with high power efficiency are appropriately combined to meet user needs. It is desired that the operation mode of the stepping motor can be selected in accordance with the above.

  The present invention has been made to solve these problems, and an object of the present invention is to select an arbitrary operation mode from among operation modes including step driving of a stepping motor and power saving driving depending on a use situation. It is an object of the present invention to provide a versatile stepping motor drive control device that can perform low noise, low vibration, and power saving drive by selecting and driving a motor.

In order to achieve the above object, the present invention comprises the following arrangement.
A drive control device for a stepping motor in which a motor control unit acquires position information and speed information of a rotor by a detection signal of a rotation detection unit, performs feedback control, and outputs a motor current to a motor coil, and the motor control unit , Mode setting means capable of selecting an arbitrary operation mode from a plurality of operation modes including step driving for constant current control of the stepping motor and power saving driving for vector control, and according to selection of the operation mode by the mode setting means In the operation program to be executed, switching is performed by the drive switching unit that switches between the step drive and the power-saving drive in each of the stepping motor operation position establishment period, the low speed period, or the high speed period. Switch the excitation phase to the stepping motor according to the driving method A motor current control unit for outputting a motor current to the serial motor coil, characterized by comprising a.
According to the above configuration, by selecting an arbitrary operation mode from the plurality of operation modes of the stepping motor by the mode setting means, the motor current according to the drive method (step drive or power saving drive) switched by the drive switching unit. The controller switches the excitation phase and outputs the motor current to the motor coil.
Therefore, the operation mode is selected according to the scene used by the user, step driving with high holding torque and high positioning accuracy in the low speed period in the position establishment period, stable rotation in the high speed period, and power efficiency are good. By using power saving drive properly, it becomes possible to drive the stepping motor with low noise, low vibration and power saving according to the customer's usage situation.

The mode setting means is a first operation mode in which the motor current vector control is performed by the power saving drive until the motor is started and stopped, and the motor is driven in the power saving mode. Driving in a constant current mode for controlling the current at a constant current, a low speed operation period and a high speed operation period are driven in the power saving mode in a second operation mode, the position establishment period and the low speed operation period are driven in the constant current mode, the third operation mode the high-speed operation period is driven by the power saving mode, a fourth operating mode the position established period and high-speed operation period the low speed operation period is driven by the power-saving mode driven by the constant current mode the has, it is desirable to have become selectable via input means of these operation modes including an external device or switch.
That is, it is desirable that the mode setting unit waits for an input from the input unit by a user and executes an operation program corresponding to an operation mode selected from the first operation mode to the fourth operation mode. .
As a result, the required torque (rotation torque, holding torque) while saving power by selecting the optimal operation mode from the operation modes including step drive and power saving drive according to the situation where the customer uses the stepping motor In addition, since the high efficiency is obtained, the versatility of the stepping motor is expanded.

The motor control unit includes PID controllers for position and / or speed corresponding to step driving and power saving driving, and the integral element and the differential element of each PID controller are before and after mode switching. It is desirable to control so that each is updated.
This makes it possible to smoothly switch between step drive and power-saving drive in each of the position establishment period, low speed period, and high speed period, and the operation becomes unstable due to operation switching, and the motor current is disturbed, causing vibration and noise. Can be prevented.

  If the stepping motor drive control device described above is used, low noise can be achieved by selecting any operation mode from among the operation modes including stepping stepping motor and power saving driving according to the situation of use. In addition, it is possible to provide a versatile stepping motor drive control device that can perform low-vibration and power-saving driving.

It is a block block diagram of the drive control apparatus of a stepping motor. It is a block block diagram which shows an example of a motor drive circuit. It is a block block diagram which shows the function of the operation program executed in a microcomputer. It is explanatory drawing which shows an example of the 1st, 2nd operation mode. It is explanatory drawing which shows an example of the 3rd, 4th operation mode.

  Embodiments of a stepping motor drive control apparatus according to the present invention will be described below with reference to the accompanying drawings. In the present embodiment, a block configuration of a drive control device for a two-phase stepping motor is illustrated as an example. The stepping motor may be any of PM type, VR type and hybrid type.

With reference to the block diagram of FIG. 1, a schematic configuration of a drive control device for a two-phase stepping motor will be described.
For example, in the PM type, the two-phase stepping motor 1 includes a permanent magnet rotor in which a permanent magnet is provided on a rotor yoke, a stator in which a motor coil is wound around pole teeth of a stator core, and a rotational position of the rotor connected to a motor shaft. And an encoder 2 (rotation detector) for detecting the rotational speed. By using the encoder 2, high reliability (no step-out) is realized. A magnetic pole sensor such as a Hall IC may be provided instead of the encoder 2. In this embodiment, since it is a two-phase stepping motor, an A-phase coil and a B-phase coil whose phases are different by 180 degrees in electrical angle are wound around the stator. A motor current flows through each phase motor coil at a predetermined timing by a motor driver circuit described later.

  The encoder signal (A / B phase, Z signal) for detecting the rotor position and speed is output to the motor control unit 3 (motor driver circuit). The motor control unit 3 outputs an excitation signal to the two-phase stepping motor 1. The motor control unit 3 controls the rotor position and the rotational speed by performing feedback control of the two-phase stepping motor 1 based on software in a fully closed loop like the AC servo motor.

The motor control unit 3 includes a microcomputer 4 having various control elements such as a CPU, a ROM, and a RAM, and a power control circuit 5 that controls the motor current. Moreover, the mode setting switch 6 which can select the operation mode of the two-phase stepping motor 1 may be provided. The microcomputer 4 controls the operation of the two-phase stepping motor 1 based on the operation mode selected by the mode setting application software provided in the personal computer 7.
The mode setting switch 6 allows the user to select one of the operation modes. The mode setting means can select a mode by input from input means including external devices such as the mode setting switch 6 and the personal computer 7. Various personal digital assistants (notebook computers, tablet PCs, etc.) can be used instead of the personal computer 7.

  Signals such as a motor rotation command and a position command are input to the motor control unit 3 from a host controller 8 (for example, a programmable logic controller (PLC)). The microcomputer 4 generates a PWM (pulse width modulation) signal based on these signal inputs, rotor position / speed information from the encoder 2, and motor current information from the power control circuit 5.

Next, FIG. 2 shows an example of a motor driver circuit. The microcomputer 4 is energized A-phase gate driver 9a outputs a PWM gate drive pulse, the 9b ON / OFF to the half-bridge circuit A, the A-phase of the motor coils through ^{A ~.} Similarly energizing PWM gate drive pulse output to the B-phase gate driver 9c, a 9d ON / OFF half-bridge circuit B, and B-phase of the motor coils through ^{B ~.} By using, for example, a high-performance gate driver and MOSFET as the components constituting each half-bridge circuit, high efficiency can be realized with low heat generation. The amount of current flowing through each phase coil is detected by current sensors 10a and 10b. The motor current is controlled by software in accordance with an operation mode described later. Further, step driving by an arbitrary angle inherent to the stepping motor can be performed according to the resolution of the encoder 2.
The microcomputer 4 is supplied with a motor drive voltage of, for example, 24V to 48V which is A / D converted as a motor drive power supply. An overvoltage protection circuit 11 is connected to protect the motor driver circuit from abnormal voltages.

Next, referring to FIG. 3, a block configuration diagram showing the function of the operation program executed in the microcomputer 4 will be described.
The operation mode is set by an application program installed in the personal computer 7 shown in FIG. The microcomputer 4 can select an arbitrary operation mode from a plurality of operation modes including step driving and power saving driving of the stepping motor 1. When the operation mode is selected, the microcomputer 4 executes a program corresponding to the operation mode, and the target locus generation unit 15 and / or one of the target position and the target speed and the current rotation speed from the encoder 2 are executed.・ Newly output the rotor speed and position command from the position information.

  When the operation program in which the target locus is generated is executed, a low speed operation servo that controls the operation of the stepping motor 1 in the low speed period and a position establishment servo that establishes the stop position in the stop period (hereinafter simply referred to as “low speed, position 14a) and a high-speed operation servo 14b that performs speed control in a high-speed period during which the stepping motor 1 rotates stably are selected and motor drive control is performed. The servo switching unit 12, which is an example of the drive switching unit, is a low-speed, position-established operation servo 14 a and a high-speed operation based on the rotor position / speed signal from the encoder 2 in the operation program executed according to the selected operation mode. The servo 14b is switched.

  Further, the current feedback gain, torque command, field command, rotor phase, etc. for the motor current control unit 13 according to the servo (low speed, position establishment operation servo 14a or high speed operation servo 14b) switched by the servo switching unit 12. Command value is output. In accordance with these command value inputs, the motor current control unit 13 generates a PWM signal, switches the excitation phase, and outputs the motor current to the motor coil.

Next, an example of an operation mode executed by software in the motor control unit 3 will be described with reference to FIGS. 4 and 5.
In FIG. 4, the first operation mode is a power saving mode in which the motor current is vector-controlled by power saving driving until the stepping motor is started and stopped (periods I to V). For example, it is suitable for users who do not need smooth rotation at less than 10 rpm and users who do not require hold characteristics equivalent to stepping motors for position establishment. As described above, the vector control of the motor current from the start to the stop of the motor provides the most power saving and the most efficient power in the operation mode. However, in the first operation mode, servo control may be disturbed in the case of a position establishment period, a low-speed rotation period, or an elastic load such as a rubber belt.

In FIG. 4, the second operation mode is a constant current mode (ordinary stepping motor drive) in which the motor current is constant-current controlled by step drive during the position establishment period (hold periods I and V), and the low speed operation period (II, IV). ) And high-speed operation period (III) are set to the power saving mode (vector control drive).
In the second operation mode, during the position establishment period (hold periods I and V), stable position establishment can be performed by the strong holding torque that is a feature of the stepping motor.

In FIG. 5, the third operation mode is the constant current mode (normal stepping motor drive) during the position establishment period (hold periods I and V) and the low speed operation periods (II and IV), and the high speed operation period (III) is omitted. The power mode (vector control drive) is set.
As a result, the position establishment period (hold periods I, V) and low speed operation periods (II, IV) perform constant current driving with high positioning accuracy, which is the greatest advantage of the stepping motor, and a high speed operation period in which the rotation speed is stable ( III) is a power saving mode (vector control drive), so that the rotation is stable from low speed to high speed, and it can be driven with low vibration and low noise over the entire area.

In the fourth operation mode, the motor position establishment period (hold periods I and V) and the high speed operation period (III) are set to the power saving mode, and the low speed operation periods (II and IV) are set to the constant current mode (normal stepping motor driving). ).
As a result, when the time during which the stepping motor is stopped is long, power saving can be achieved, and the motor can be stably rotated from the low speed range to the high speed range while the motor is being driven.

  In addition, the motor control unit 3 includes PID controllers for position and / or speed corresponding to step driving (constant current mode) and power saving driving (power saving mode). Control is performed so that the integral element and the derivative element of the PID controller of both or either of the speeds are updated before and after the mode switching. As a result, it is possible to prevent the operation from becoming unstable when the operation is switched to a different operation during the operation mode, and the motor current being disturbed to generate vibration and noise.

In addition, although the operation mode 1st-4th operation mode was demonstrated, it is free to modify software and to provide an additional operation mode.
Further, the constant current control of the stepping motor is not limited to full step driving, and may be micro step driving.
Further, although the two-phase stepping motor has been described in the present embodiment, this may be a three-phase or more multi-phase stepping motor, and the motor may be either an inner rotor type or an outer rotor type. .

1 Two-phase stepping motor
2 Encoder
3 Motor controller
4 Microcomputer
5 Power control circuit
6 Mode setting switch
7 Personal computer
8 Host controller
9a, 9b A phase gate driver
9b, 9d B phase gate driver
10a, 10b Current sensor
11 Overvoltage protection circuit
12 Servo switching part
13 Motor current controller
14a Low speed, position establishment operation servo 14b High speed operation servo 15 Target locus generator

Claims (3)

A drive control device for a stepping motor, in which a motor controller acquires position information and speed information of a rotor by a detection signal of a rotation detector, performs feedback control, and outputs a motor current to a motor coil,
The motor control unit is capable of selecting an arbitrary operation mode from a plurality of operation modes including step driving for constant current control of the stepping motor and power saving driving for vector control, and
In the operation program executed in response to the selection of the operation mode by the mode setting means, driving for switching between the step driving and the power saving driving in the position establishment period, the low speed period, or the high speed period of the stepping motor. A switching unit;
A motor current control unit that switches the excitation phase to the stepping motor according to the driving method switched by the drive switching unit and outputs a motor current to the motor coil;
The mode setting means is a first operation mode in which the motor current vector control is performed by the power saving drive until the motor is started and stopped, and the motor is driven in the power saving mode. Driving in a constant current mode for controlling the current at a constant current, a low speed operation period and a high speed operation period are driven in the power saving mode in a second operation mode, the position establishment period and the low speed operation period are driven in the constant current mode, The third operation mode is driven in the power saving mode during the high speed operation period, the fourth operation mode is driven in the power saving mode during the position establishment period and the high speed operation period, and is driven in the constant current mode during the low speed operation period. the it has, characterized in that it becomes selectable through the input means including said external device, or switch the operation modes Steppin Motor drive control device. The motor control unit includes a PID controller of position and / or speed corresponding to the step drive and the power saving drive, and the integral element and the derivative element of the PID controller are mode-switched. The stepping motor drive control device according to claim 1, wherein the stepping motor is controlled so as to be updated before and after each of the steps. The mode setting unit waits for an input from the input unit by a user and executes an operation program corresponding to an operation mode selected from the first operation mode to the fourth operation mode. Item 3. A stepping motor drive control apparatus according to Item 2.

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