JP2009005546A - Control circuit of motor rotation, drive unit for movement, and control method of motor rotation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control circuit of motor rotation, by which the motor control circuit detects a temperature and performs control to lower a revolution speed if the temperature is low, by adding a small amount of hardware, when driven by a stepping motor. <P>SOLUTION: The stepping motor rotation control circuit 10 includes a pulse control circuit 11, wherein the pulse control circuit has a circuit which detects the temperature and outputs a level (Vth1) having negative characteristics to the temperature, and a circuit which supplies a stepping motor driver circuit 20 with a pulse signal wherein a pulse quantity per cycle is decreased, as the level to be output becomes high. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a motor rotation control circuit, a moving drive device, and a motor rotation control method, and in particular, motor rotation in which rotation control of a motor driven in response to a pulse is considered in consideration of temperature, as represented by a stepping motor. The present invention relates to a control circuit, a mobile drive device including the control circuit, and a motor rotation control method.

  There are devices and mechanisms that move a target by rotating a drive mechanism by a stepping motor. In such an apparatus or mechanism, the rotation control of the stepping motor is performed by inputting a pulse having a constant cycle and a reference voltage to the stepping motor driver circuit and rotating the stepping motor or the like.

  However, when a rubber roller is rotated by a stepping motor and driven using the frictional force of the rubber, the friction coefficient of the rubber generally tends to be low at low temperatures, and rotation control considering temperature is desirable. It is.

  A motor driven in response to a pulse may be called a pulse motor. However, what is called a stepping motor here includes the pulse motor.

  As a technique related to a technique for controlling the rotation speed of a stepping motor (pulse motor) depending on temperature, there is a movement amount control device of Patent Document 1. The movement amount control device is a device that controls the movement amount of a moving body per unit time in an actuator that moves a moving body by driving a drive source by pulse control.

  The movement amount control device includes a clock generation unit, a clock count unit that counts a clock and outputs a pulse, a unit that generates a driving pulse every time a predetermined number of clocks are counted, and a predetermined number based on a pulse of the clock count unit. Frequency changing means for thinning out the clock under the above conditions (temperature correction ON, etc.) to change the frequency of the clock and input it to the pulse generating means.

  As an application example, in an image recording apparatus, a male screw of a ball screw mechanism is formed on a shaft in the rotation axis direction (horizontal direction) of a rotating drum, and the shaft is driven by a pulse motor to be screwed into the screw (see FIG. An example is described in which the temperature of the moving amount of the mechanism that moves the (beam) head in the horizontal (sub-scanning) direction is corrected.

  Since the shaft and the rotating drum expand and contract due to temperature changes caused by the emission of light beams, etc., if the temperature is lower than 25 degrees, the moving speed is corrected to decrease in accordance with the contraction of the recording plate on the rotating drum. To do.

  In the correction, the setting calculation unit including the CPU calculates the count cycle of the clock pulse signal (the count number of the clock count means * clock cycle) according to the value for each device read from the memory and the temperature information from the temperature sensor. Is corrected by setting the thinning cycle (see Patent Document 1).

JP 2003-339194 A ([0012] [0022] [0065])

  In the method of inputting a pulse with a fixed period and a reference voltage described above, the rotational speed and rotational torque are constant regardless of the temperature, so it is not possible to compensate for the decrease in driving force due to a decrease in the friction coefficient of rubber at low temperatures. However, there is a problem that a driving force originally required cannot be obtained.

  As a result, the arrival time of the mobile drive object takes a delay time, and it is possible to perform linked control that predicts the arrival time and prepares for another drive operation (movement in another direction, pickup, etc.) after arrival in advance. It leads to the inconvenience of disappearing.

  Further, in the related art of Patent Document 1, in addition to the CPU and memory for calculation, the temperature sensor and temperature sensor output (voltage, etc.) are converted into digital values and read by the CPU, etc. and the thinning cycle is held and counted. Counter and means for presetting the thinning cycle calculated by the CPU in the counter are required, and a considerable amount of hardware needs to be added.

  An object of the present invention is to provide a motor rotation control circuit, a movement drive device, and a motor rotation control method that have solved the above problems.

The motor rotation control circuit of the present invention is
A circuit that senses the temperature and outputs a level having a negative characteristic with respect to the temperature;
A pulse control circuit including a circuit for supplying a stepping motor driver circuit with a pulse signal obtained by reducing the number of pulses per cycle as the output level increases.

The movement driving device of the present invention includes a driving roller for moving a driving object,
A drive mechanism including a mechanism for transmitting the rotation drive of the stepping motor to the rotation shaft of the drive roller;
The stepping motor;
A constant current type stepping motor driver circuit for driving the stepping motor;
And a motor rotation control circuit.

The motor rotation control method of the present invention is a method of controlling the rotation of a stepping motor through a stepping motor driver circuit,
A procedure for sensing temperature and outputting a level with negative characteristics with respect to temperature,
A step of supplying a pulse signal obtained by reducing the number of pulses per period to the stepping motor driver circuit as the output level increases;
And a step of supplying a reference voltage reduced in proportion to the temperature rise to the stepping motor driver circuit.

  According to the present invention, when driving by a stepping motor, the motor control circuit senses the temperature, and the control for lowering the rotation speed at a low temperature can be realized by adding a small amount of hardware.

  Next, embodiments for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an overall configuration of a first embodiment of a mobile drive device 1 of the present invention.

  Referring to FIG. 1, the mobile drive device 1 includes a stepping motor rotation control circuit 10, a stepping motor driver circuit 20, a stepping motor 30, and a drive mechanism 40.

  The stepping motor rotation control circuit 10 includes a pulse control circuit 11 and a reference voltage control circuit 12. The pulse control circuit 11 detects a temperature change, controls a pulse input to the stepping motor driver circuit 20, and controls a rotation frequency of the stepping motor 30 by controlling a pulse frequency of the stepping motor driver circuit 20.

  The reference voltage control circuit 12 detects the temperature change, controls the reference voltage input to the stepping motor driver circuit 20, and controls the rotational current of the stepping motor 30 by controlling the drive current of the stepping motor (temperature). As the value decreases, the rotational torque increases.

  FIG. 2 is a diagram showing a specific example of the drive mechanism 40 of the mobile drive device 1 of FIG. 1, and the figure also includes a stepping motor 30 and a drive object 50. The drive mechanism 40 is attached to the rotating roller 41 with a rubber for driving rotating with the surface in contact with the bottom surface of the driving object 50, the driving gear 43 attached to the rotating shaft of the roller 41, and the rotating shaft of the stepping motor 30. And a driving belt 44 stretched between the driving gear 43 and the driving gear 42.

  The rotation drive of the stepping motor 30 is transmitted to the rotation shaft of the roller 41 with rubber for driving through the drive mechanism 40, and the roller 41 with rubber for driving rotates to drive the object 50 to move.

  The drive object 50 is a recording medium stored in, for example, a cartridge, and the approach and arrival of the target position are detected by a sensor or the like (not shown), and the pulse oscillation of the pulse control circuit 11 is controlled.

  FIG. 3 is a circuit diagram showing a detailed configuration of the stepping motor rotation control circuit 10 shown in FIG. The stepping motor rotation control circuit 10 includes a pulse control circuit 11 and a reference voltage control circuit 12.

  The pulse control circuit 11 is connected to an NTC thermistor 110 (Negative Temperature Coefficient thermistor), a resistor 111, a triangular wave oscillator 112, a comparator 113, a pulse oscillation circuit 114, a gate element 115, and an output terminal of the gate element 115. Pulse output terminal 116.

One end of the NTC thermistor 110 is connected to the power supply voltage (VCC) through the resistor 111, and the other end is grounded. The comparator 113 has the minus terminal connected to the one end of the NTC thermistor 110 and the plus terminal connected to the output of the triangular wave oscillator 112, and compares the levels.
The gate element 115 passes / blocks the output of the pulse oscillation circuit 114 according to the output signal value of the comparator 113. The pulse output from the pulse output terminal 116 is supplied to the stepping motor driver circuit 20.

  Since the pulse oscillation circuit 114 is an existing pulse oscillation circuit obtained by peripheral device control or CPU control, details are omitted.

  The reference voltage control circuit 12 has a configuration in which a resistor 121 and an NTC thermistor 120 are serially connected between a reference voltage Vref and ground (ground), and a connection point between the resistor 121 and the NTC thermistor 120 is connected to a reference voltage output terminal 122. And supplied to the stepping motor driver circuit 20.

  Although the configuration of the first embodiment has been described in detail above, the stepping motor driver circuit 20 and the stepping motor 30 in FIG. 1 are a constant current type stepping motor driver circuit and a constant current type stepping motor, respectively.

  Both of these are well known to those skilled in the art, and are not directly related to the present invention, and thus detailed configuration thereof is omitted.

Next, the operation of the first embodiment of the mobile drive device 1 of the present invention will be described with reference to the drawings.
The operation of the stepping motor rotation control circuit 10 of FIG. 3 will be described using the time charts shown in FIGS. The voltage Vth1 resistance-divided by the resistor 111 and the NTC thermistor 110 is input to the negative terminal of the comparator 113 and compared with a triangular wave input to the positive terminal of the comparator 113.
The output waveform of the comparator 113 is as shown in the second time chart of FIG.

  Next, as shown in FIG. 4, the gate element 115 passes / blocks the output of the pulse oscillation circuit 114 in accordance with the output level (high / low) of the comparator 113, that is, both waveforms are ANDed and output.

  Further, the NTC thermistors 110 and 120 have a negative temperature characteristic that the resistance value decreases as the temperature rises as shown in FIG. Accordingly, the voltage Vth1 obtained by dividing VCC by the resistor 111 and the NTC thermistor 110 increases as the detected temperature of the NTC thermistor 110 decreases as shown in FIG.

  When the detected temperature of the NTC thermistor 110 decreases, the voltage value of Vth1 increases as shown in FIG. 7, and the pulse width of the output of the comparator 113 decreases as shown in FIG. 5 compared to FIG.

  As shown in FIG. 5, when the pulse width of the output of the comparator 113 decreases, the pulse ANDed with the output of the pulse oscillation circuit 114 becomes the output pulse of the gate element 115, and the pulse from the output pulse of the gate element 115 shown in FIG. The frequency drops.

  When the pulse frequency is lowered, the rotation speed of the stepping motor 30 is proportional to the pulse frequency, and thus the rotation speed is lowered.

  Therefore, the rotation control of the stepping motor 30 in consideration of the temperature change to compensate for the decrease in the rubber friction coefficient of the driving rubber-equipped roller 41 at a low temperature (reducing the speed at a low temperature) is simply added with a small amount of hardware. realizable.

  Further, as shown in FIG. 3, the voltage Vth2 divided by the resistor 121 and the NTC thermistor 120 increases as the temperature decreases, as with the voltage Vth1 shown in FIG.

  Vth2 is a reference voltage of the stepping motor driver circuit 20. In general, when the reference voltage of the constant current type stepping motor 30 increases, the driving current of the stepping motor 30 increases, and the rotational torque of the stepping motor 30 can be increased.

  As described above, in the above-described embodiment, by adding a few more resistance circuits, as the rotation control of the stepping motor 30 in consideration of the temperature change, the control for increasing the rotation torque of the stepping motor 30 at a low temperature is also performed. ing.

  In the above description of the first embodiment, the resistor circuit including the thermistor of the pulse control circuit 11 is a circuit that divides VCC by the resistor 111 and the NTC thermistor 110. However, as shown in FIG. Alternatively, an additional resistor 119 may be inserted in parallel.

  In this way, the rate of increase / decrease in the number of pulses with respect to temperature can be moderated without performing level comparison only in the low potential portion of the triangular wave.

  Also, with respect to a resistor circuit including the thermistor of the reference voltage control circuit 12, a resistor may be inserted in parallel with the NTC thermistor 120 as necessary to adjust the center level of the reference voltage.

  The mechanism for driving in contact with the driven object 50 has been described as the roller 41 with rubber for driving. However, even if the mechanism for driving in contact with the belt conveyor is made of a member whose frictional force decreases at low temperatures, the motor rotates. The same correction may be performed by the control.

  In the above description of the first embodiment, the stepping motor rotation control circuit 10 performs temperature-dependent rotation torque control by the reference voltage control circuit 12 in addition to temperature-dependent rotation speed control by the pulse control circuit 11. However, there is another embodiment in which only the temperature-dependent rotation speed control by the pulse control circuit 11 is performed.

  Next, a second embodiment of the mobile drive device 1 of the present invention will be described. Also in the second embodiment, the overall configuration of the mobile drive device 1 is as shown in FIG. 1, and the basic configuration of the stepping motor rotation control circuit 10 is the same, but the pulse control circuit 11A is further devised.

FIG. 9 is a circuit diagram showing details of the pulse control circuit 11A of the second embodiment. In FIG. 9, the flip-flop 117 invalidates the output pulse of the comparator 113 obtained by the temperature detection.
That is, the output of the flip-flop 117 set to the high level is ORed by the OR element 118, and the high fixed level is supplied to the gate element 115. Thereby, the temperature-detected pulse can be arbitrarily enabled / disabled.

  The operation of the pulse control circuit 11A of FIG. 9 will be described using the time chart shown in FIG. An OR element 118 is disposed between the comparator 113 and the gate element 115, and a flip-flop 117 is connected to one input terminal of the OR element 118.

  The flip-flop 117 outputs “0” or “1” (high or low) in a 1-bit configuration by a peripheral device or CPU control.

  By setting the output of the flip-flop 117 to “1” (high), the output of the OR element 118 can be set to “1” (high), and the pulse output terminal 116 output via the gate element 115 is connected to the pulse output terminal 116. The output pulse of the pulse oscillation circuit 114 is output unconditionally.

  In this configuration, the flip-flop 117 and the OR element 118 may be configured by switch control using a transistor.

  One bit in a control register such as the pulse oscillation circuit 114 accessed by the peripheral device or the CPU may be used instead of the flip-flop 117.

  As described above, in the second embodiment of the present invention, since the temperature-detected pulse is invalidated by the flip-flop 117, the temperature-detected pulse is set when the peripheral device or the CPU sets the flip-flop 117. Can be arbitrarily enabled or disabled.

  In the first and second embodiments of the mobile drive device 1 described above, the output of the triangular wave oscillator 112 is input to the negative input of the comparator 113 of the pulse control circuit 11 of the stepping motor rotation control circuit 10. However, the output of a sine wave oscillator or a trapezoidal wave oscillator may be input instead of the triangular wave oscillator 112.

It is a block diagram which shows the whole structure of 1st Embodiment of the movement drive apparatus 1 of this invention. It is a figure which shows the specific example of the drive mechanism 40 of the movement drive apparatus 1 of this invention. It is a circuit diagram which shows the detailed structure of the stepping motor rotation control circuit 10 of this invention. It is a time chart which shows operation | movement of the stepping motor rotation control circuit 10 of this invention. It is a time chart which shows operation | movement of the stepping motor rotation control circuit 10 of this invention. It is a figure which shows the relationship between the temperature of NTC thermistor, and resistance value. It is a figure which shows the change by the temperature of the voltage Vth1 and the voltage Vth2. 6 is a diagram illustrating another example of a resistance circuit of the pulse control circuit 11 or the reference voltage control circuit 12. FIG. It is a circuit diagram which shows the detail of the pulse control circuit 11A of 2nd Embodiment of the movement drive apparatus 1 of this invention. It is a time chart which shows operation | movement of 11 A of pulse control circuits of the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Movement drive device 10 Stepping motor rotation control circuit 11, 11A Pulse control circuit 110 NTC thermistor 111 Resistance 112 Triangular wave oscillator 113 Comparator 114 Pulse oscillation circuit 115 Gate element 116 Pulse output terminal 117 Flip-flop 118 OR element 119 Resistance 12 Reference voltage control circuit DESCRIPTION OF SYMBOLS 120 NTC thermistor 121 Resistance 122 Reference voltage output terminal 20 Stepping motor driver circuit 30 Stepping motor 40 Driving mechanism 41 Roller with rubber for driving 42 Driving gear 43 Driving gear 44 Driving belt 50 Driving object

Claims (12)

A circuit that senses temperature and outputs a level having a negative characteristic with respect to temperature; and a circuit that supplies a pulse signal with a reduced number of pulses per period to a stepping motor driver circuit as the output level increases. A motor rotation control circuit comprising a pulse control circuit. A reference voltage control circuit for supplying a reference voltage to the stepping motor driver circuit;
2. The motor rotation control circuit according to claim 1, wherein the reference voltage control circuit senses a temperature and supplies a reference voltage that decreases in proportion to a temperature increase to the stepping motor driver circuit. A resistor circuit that includes an NTC thermistor and outputs a level having a negative characteristic with respect to temperature;
The output monotonically increases from the intermediate level in the previous half cycle and reaches the maximum level, then decreases monotonically and returns to the intermediate level.In the later half cycle, the output is reversed from the previous half cycle with the intermediate level as an axis. An oscillator that generates a periodic wave whose level changes;
Comparing the output of the resistance circuit and the level of the output of the periodic wave, and generating a pulse that becomes high level during the period when the latter level is equal to or higher than the former level,
A pulse oscillation circuit;
3. The motor according to claim 1, further comprising: a gate element that passes an output pulse of the pulse oscillation circuit and supplies the pulse to the stepping motor driver circuit while the pulse generated by the comparator is at a high level. Rotation control circuit. 4. The motor rotation control circuit according to claim 3, wherein the oscillator that generates the periodic wave is a triangular wave oscillator. 4. The motor rotation control circuit according to claim 3, wherein the oscillator for generating the periodic wave is a sine wave oscillator or a trapezoidal wave oscillator. The pulse control circuit is a flip-flop set by a control unit or CPU on the host side of the motor rotation control circuit;
4. The motor rotation according to claim 3, further comprising a correction invalidation circuit including a logic circuit that fixes a pulse signal from the comparator to a high level according to a value of the flip-flop and inputs the pulse signal to the gate element. Control circuit. 4. The motor rotation control circuit according to claim 3, wherein the resistance circuit is a circuit that connects one end of an NTC thermistor to a power supply voltage through a resistor, grounds the other end, and outputs the level of the one end. 4. The circuit according to claim 3, wherein the reference voltage control circuit is a circuit that connects one end of an NTC thermistor to a power supply voltage through a resistor, grounds the other end, and outputs the level of the one end as a reference voltage. Motor rotation control circuit. A drive mechanism that includes a drive roller that moves the drive object, and a mechanism that transmits the rotational drive of the stepping motor to the rotation shaft of the drive roller;
The stepping motor;
A constant current type stepping motor driver circuit for driving the stepping motor;
A movement drive apparatus comprising the motor rotation control circuit according to claim 1. The moving drive device according to claim 9, wherein the driving roller is a roller with a member whose friction coefficient decreases at a low temperature. A method for controlling the rotation of a stepping motor through a stepping motor driver circuit,
A procedure for sensing temperature and outputting a level with negative characteristics with respect to temperature,
A step of supplying a pulse signal obtained by reducing the number of pulses per period to the stepping motor driver circuit as the level increases;
And a step of supplying a reference voltage reduced in proportion to the temperature rise to the stepping motor driver circuit. A procedure for including a NTC thermistor and outputting a level having a negative characteristic with respect to temperature,
In the previous half cycle, the output is monotonically increased from the intermediate level to the maximum level, then monotonically decreased, and then returned to the intermediate level. To generate a periodic wave by changing
A procedure for comparing a level output having a negative characteristic with respect to the temperature and a level of the output of the periodic wave, and generating a pulse that becomes a high level during a period in which the latter level is equal to or higher than the former level;
A procedure for oscillating a rectangular pulse;
12. The motor rotation control method according to claim 11, further comprising a step of passing the rectangular pulse and supplying the generated pulse to the stepping motor driver circuit during a period in which the generated pulse is at a high level.

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