JPH06343296A - Stepping motor controller - Google Patents

Abstract

PURPOSE:To provide a stepping motor controller which makes damping hardly occur when a stepping motor shuts down. CONSTITUTION:A stepping motor controller 17 is provided with a program 24 for sampling of a set target value, a stepping motor accelerating and reducing program 25 which calculates a difference between the set target value and a current position of a stepping motor 15 and then accelerates or reduces the stepping motor 15 according to the calculated difference and stops the stepping motor 15 at the set target value, and a driving time countering program 29 which counters the driving time CMOVE of the stepping motor 15. This controller also has a resonance discrimination program 27 which discriminates that resonance occurs when the driving time CMOVE agrees with a multiple of a cycle which corresponds to a natural frequency of a driving system of the stepping motor and a reverse phase excitation program 28 which conducts reverse-phase excitation for stopping the stepping motor when it is discriminated that resonance occurs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a step motor control device for rapidly accelerating and decelerating a step motor to a changing target stop position when the step motor target stop position changes. The present invention relates to a step motor control device capable of reducing vibration generated by acceleration / deceleration when stopping a motor at a set target value.

[0002]

2. Description of the Related Art In recent years, a method of electronically controlling a throttle valve of an automobile engine by a step motor has been implemented, and a step motor control device for controlling driving and stopping of the step motor is widely used in automobiles. . Here, since it is necessary to control the opening / closing amount of the throttle valve by following the depression amount of the accelerator,
The step motor control device measures the amount of depression of the accelerator as analog data with a potentiometer or the like, samples the measured value of the potentiometer at a constant interval, A / D-converts the target value, and sets the step motor according to the target value. By controlling the stop position, the opening / closing amount of the throttle valve is controlled.

Generally, a control device for a step motor accurately and accurately accelerates the step motor to a target stop position of the step motor, decelerates when the set target value approaches, and reduces damping generated at the time of stop. A method for quickly stopping the step motor is used. That is, for example, the following method has been proposed as a method for reducing damping that occurs when the step motor is stopped. Japanese Patent Laid-Open No. 1-91699 discloses a method of temporarily interrupting the current supplied to the target step when stopping the step motor. Further, Japanese Patent Laid-Open No. 61-94590 discloses a method of temporarily interrupting the current supplied to the step immediately before the target step. Further, Japanese Patent Application Laid-Open No. 62-16095 discloses a method of temporarily exciting a reverse phase at a target step.

[0004]

However, the conventional step motor control device has the following problems. That is, in a step motor control device that adjusts the opening and closing of a throttle valve, a potentiometer that measures the amount of depression of the accelerator is sampled at regular sampling times to bring the step motor close to the sampled target value, and the target value is constant. Is controlled to stop the step motor. Then, in order to quickly rotate the step motor to the target value, control is usually performed to perform an acceleration / deceleration cycle in which the rotation speed is accelerated at the start of rotation and decelerated when approaching the target value. Therefore, due to the acceleration / deceleration cycle of the step motor, swell vibration is generated in the drive system of the step motor including the throttle valve.

However, in the conventional control when the step motor is stopped, the presence or absence of the swell vibration is not taken into consideration. Therefore, depending on the state of the swell vibration when the step motor is stopped, a method for reducing the damping is performed. On the contrary, in some cases, the damping may be strengthened. One specific example is shown in FIG. In the figure, M indicates a target value obtained by measuring the amount of depression of the accelerator as analog data with a potentiometer, sampling for a fixed sampling time A, and A / D converting. P indicates the current step of the step motor. Also MSP
D represents the condition of the drive pulse applied to the step motor, and is specifically given as the drive frequency and the excitation time. Here, the drive frequency given to the step motor and its excitation time are given from the difference between the current position of the step motor and the target value, for example, using a table as shown in FIG.

That is, when M changes, the step motor is sequentially accelerated to MSPD = 1, 2, 3, in the direction of eliminating the difference MA between the current position of the step motor and the target value.
Then, when the current position of the step motor approaches the target value, the step motor M
SPD is gradually decelerated to 2,1. At this time, the time A during which the step motor is driven is as shown in the table of FIG.
Since the excitation time of D = 2 is 1.429 ms and the excitation time of MSPD = 3 is 1.186 ms, the total A = 8.04.
4 ms.

However, according to the results of experiments conducted by the inventor of the present application, as shown in FIG. 6, the driving time of the step motor corresponds to the natural frequency of 150 to 180 Hz of the driving system of the step motor for driving the throttle valve. It was confirmed that the damping when the throttle valve was stopped was large when the cycle Tc was equal to a multiple of 5.6 to 6.7 ms. That is, the driving time of the step motor is Tc,
When the throttle valve is in the vicinity of 2Tc, 3Tc, and 4Tc, large damping occurs when the throttle valve is stopped, and in other cases, damping does not occur, or even if it occurs, the amplitude of vibration is small and a level that does not pose a problem. It was confirmed.

Considering this in the above specific example, A =
Since 8.044 ms is not a multiple of Tc, (a) in FIG.
As shown in, even if it is stopped as it is, damping is small and there is no problem. However, in the conventional method of reducing damping of the step motor, for example, as shown in (b) of FIG. 7, since the anti-phase G is always excited at the target step, the vibration K is newly excited by the anti-phase G excitation. There was a problem that caused it. When the step motor is stopped and restarted immediately, even if the step motor controller stops the step motor, the drive system of the step motor is vibrating, so the throttle valve There was a problem that the behavior became unstable for a while and did not follow the accelerator depression amount. Further, in the worst case, there was a problem of step-out during reversal.

In order to avoid this, in the conventional step motor control device, for example, when the step motor is driven by reversing, the throttle valve is stopped at the target stop position once and then at least about 20 to 30 ms. Needed to be held in a stopped state. Therefore, when the accelerator depression amount is reversed from acceleration to deceleration, there is a problem in that a delay occurs.

The present invention has been made to solve the above problems, and when the step motor is stopped,
An object of the present invention is to provide a step motor control device in which damping is less likely to occur.

[0011]

To achieve this object, a step motor control device of the present invention comprises a sampling means for sampling a set target value for stopping a step motor, a sampled set target value and a current step motor. And a step motor acceleration / deceleration means for calculating a difference from the position, accelerating the step motor according to the difference, decelerating the step motor when approaching the set target value, and stopping the step motor at the set target value. In the step motor control device, drive time counting means for counting the drive time from when the step motor is driven to when it is stopped at a set target value, and the counted drive time is the natural frequency of the drive system of the step motor. Resonance determining means that determines that resonance has occurred and that the resonance determining means determines that resonance has occurred when it matches a multiple of the corresponding cycle. If, and a vibration reducing means for performing control for reducing the vibration when stopping the stepping motor.

In the step motor control device having the above structure, the vibration reducing means temporarily cuts off the current at the target step supplied to the step motor, and the step immediately before the target step supplied to the step motor. It is characterized in that it is either a means for temporarily interrupting the current of 1) or a means for temporarily exciting a reverse phase current to the step motor. Further, in the step motor control device having the above configuration, the cycle corresponding to the natural frequency of the drive system of the step motor is 5.2 to 7.2 ms.

[0013]

The step motor of the present invention having such a structure drives the throttle valve of the engine through the drive system. Here, the natural frequency of the drive system of the step motor including the throttle valve and the step motor is 15
It has been confirmed by experiments that the frequency is in the range of 0 to 180 Hz. Further, the sampling means of the step motor control device samples a set target value from a potentiometer that measures the accelerator depression amount that changes with the passage of time. Further, the step motor acceleration / deceleration means calculates the difference between the sampled set target value and the current position of the step motor, accelerates the step motor according to the difference, and sets the current position of the step motor to the set target value. When approaching, the step motor is decelerated and the step motor acceleration / deceleration cycle is performed to stop the step motor at the set target value.

Here, the drive time of the step motor is determined by the natural frequency of the drive system driven by the step motor, which is 150 to 1
When the cycle coincides with the cycle of 5.2 to 7.2 ms corresponding to 139 to 192 Hz obtained by multiplying 80 Hz by the safety factor, the resonance occurrence determining means determines that damping vibration is likely to occur, and drives the step motor. Is not coincident with the cycle corresponding to the natural frequency, the resonance occurrence determining means determines that damping vibration is unlikely to occur. Then, the vibration reducing means performs vibration reduction control such as temporarily exciting a reverse phase current to the step motor only when the resonance determining means determines that the vibration is likely to occur, and the resonance determining means When it is determined that vibration is unlikely to occur, vibration reduction control is not performed, and therefore, when there is no possibility of resonance, extra vibration reduction control is not performed to cause damping. Therefore, the throttle valve can be stopped quickly and stably, and the amount of intake air to the engine can be accurately controlled. Also,
Even if the accelerator is reversed from acceleration to deceleration, it is possible to quickly respond.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the step motor control device 17 according to the first embodiment. An intake pipe 13 for inhaling a mixed gas of gasoline and air is connected to an automobile gasoline engine 11. A throttle valve 12 for adjusting the amount of mixed gas supplied to the gasoline engine 11 is held in the intake pipe 13 so as to be rotatable about a throttle shaft 14 with respect to the intake pipe 13. The throttle shaft 14 is connected to the output shaft of the step motor 15 via a reduction mechanism. The step motor 15 is connected to the step motor drive circuit 18 of the step motor controller 17. Drive circuit 18
Is connected to the CPU 19, which is an arithmetic unit. CPU
A RAM 2 for temporarily storing data etc. in 19
3. A ROM 22 storing a control program and the like is connected.

The ROM 22 has a sampling program 24 for sampling the accelerator data measured by the potentiometer 16 at a constant sampling time T.
Is remembered. In addition, the ROM 22 calculates the difference between the sampled value and the current position of the step motor, accelerates the step motor 15 via the drive circuit 18 according to the difference, and the step motor 15 approaches the sampled value. A step motor acceleration / deceleration program 25 for decelerating the step motor 15 and stopping the step motor 15 at a sampling value is stored.

The ROM 22 has a step motor 1
A drive time counting program 29 for counting the drive time CMOVE of the step motor 15 from the start of the rotation of 5 to the stop thereof is stored. Further, in the ROM 22,
A resonance determination program 27 is stored that determines whether the counted drive time CMOVE matches the cycle corresponding to the natural frequency of the drive system driven by the step motor 15. Further, the ROM 22 has a resonance determination program 27.
However, when it is determined that the drive time CMOVE and the period corresponding to the natural frequency match, temporary reverse phase excitation is performed to reduce the vibration generated in the step motor 15 when the step motor is stopped. A reverse phase excitation program 28 to be given is stored. Further, an A / D converter 20 for A / D converting the accelerator data, which is analog data measured by the potentiometer 16, is connected to the CPU 19. The A / D converter 20 is connected to the potentiometer 16 for measuring the depression amount of the accelerator 26 via the input interface 21.

Next, the operation of the step motor control device 17 having the above configuration will be described. When the driver operates the accelerator 26, the potentiometer 16 measures the amount of movement of the accelerator 26 as linear analog data. The CPU 19 fetches the analog data of the potentiometer 16 from the input interface 21 at a constant sampling time T by the sampling program 24, A / D-converts it by the A / D converter 20, and RAM 23 as the sampled target value.
Remember.

FIG. 2 shows a diagram for explaining the control state of the step motor. In FIG. 2, TSTEP indicates a target value obtained by sampling and A / D converting the measurement value of the potentiometer 16, that is, a target step position at which the step motor 15 driving the throttle valve 12 should be stopped. STEP indicates the current step position of the step motor 15. Further, MSPD indicates the condition of the drive pulse given to the step motor, and more specifically, as shown in FIG. 5, it is given as the drive frequency and the excitation time.

A method of accelerating and decelerating the step motor 15 will be described. FIG. 3 shows the step motor acceleration / deceleration program 25 and the drive time counting program 2 of the step motor controller 17.
9, the operation of the resonance determination program 27 and the anti-phase excitation program 28 is shown by a flowchart. This flowchart is activated by a timer interrupt at the timing when the step motor 15 completes one step operation. At the beginning,
It is determined whether the anti-phase excitation command flag FLG for executing the anti-phase excitation program 28 is 0 (S1). As will be described later, when the step motor 15 is stopped, if the drive time CMOVE matches the cycle corresponding to the natural frequency of the drive system of the step motor, FLG = 1.

If FLG = 0 (S1, YES), it is determined that it is not the stop timing of the step motor 15, and the step STEP which is present in the step motor 15 is updated by one step toward the target step TSTEP (S2). .
Next, the difference DSTEP between the target step TSTEP and the step STEP that the step motor 15 currently has is calculated,
DSTEP and current step motor 15 speed MSPD
If DSTEP> MSPD, MSPD is increased by 1 to accelerate the step motor 15 (S3), and D
If STEP <MSPD, MSPD is decremented by 1 and the step motor 15 is decelerated (S3). DSTEP = MS
If PD, constant speed is maintained without changing MSPD (S
3).

Next, when the target step is reached, the MSPD is reached.
= 0 (S4, YES), the step motor 15
The drive time CMOVE after the start of the drive is in the resonance range in which resonance is highly likely to occur, that is, the period 5.2 to 7. Corresponding to the natural frequency of the drive system of the step motor 15 that drives the throttle valve. It is determined whether or not it matches a multiple of 2 ms (S7). This is the resonance determination program 27. When the resonance determination program 27 determines that resonance is likely to occur (S7, YES), FLG is set to 1
(S9). Next, TR1 is put in the excitation time TSPD (S10), and the process proceeds to S11. On the other hand, when it is determined that the possibility of occurrence of resonance is low (S7, NO), TR is added to TSPD.
Enter 0 (S8) and proceed to S11. Next, since the step motor 15 has stopped, the next drive time CMO
C stored in RAM 23 for counting VE
MOVE is cleared to 0 (S11). On the other hand,
If the target step has not been reached, MSPD is not 0 (S4, NO), so the excitation time TSPD corresponding to MSPD is read from FIG. 5 (S5). Next, the TSPD read in is added to CMOVE (S6), and the process proceeds to S12.

If FLG is not 0 (S1, N
O), it is determined whether FLG is 1 (S14). FLG
If = 1 (S14, YES), the process proceeds to S15 to perform the anti-phase excitation. That is, STEP is set to 1 in the reverse direction.
By performing step updating (S15), a reverse phase current step is prepared. Next, FLG = 2 (S1
6). Next, set TR2 to TSPD (S1
7) Go to S12. On the other hand, if FLG is neither 0 nor 1 (S14, NO), STEP is returned by one step in the forward direction (S18), and FLG is set to 0 (S1
9), set TR3 to TSPD (S20), S1
Go to 2.

Next, in the present embodiment, since the 4-phase step motor is controlled by the 1-2 phase excitation, the pattern shown in FIG. 4 is obtained from the lower 3 bits of the current step STEP of the step motor. The step motor 15 is excited for the drive frequency and the excitation time shown in 5 (S12). Then T
The interrupt timer is set after SPD (S13). Then, after the interruption time has elapsed, the process proceeds to S1 again.

Next, the above flow chart will be described with reference to a concrete example. When in the position of step ST1 in FIG.
LG = 0 (S1, YES), and if that step is used as a reference, STEP = 0. Therefore, STEP = 1 results in STEP = 1 (S2). On the other hand, since the target step TSTEP = 9 and STEP = 1, DSTEP = 8 and MSPD = 0, so DS
TEP> MSPD, and MSPD is increased from 0 to 1 (S3). Next, since MSPD = 0 is not satisfied (S
4, NO) and the excitation time of 2.000 ms corresponding to MSPD = 1 shown in FIG. 5 is read out and stored as TSPD (S5). Then, CMOVE = 0 and TSPD = 2.00
0 ms is added to set CMOVE = 2.000 ms (S6). Next, the drive pulse having the drive frequency of 500 pps shown in FIG. 5 is applied to the step motor 15 via the drive circuit 18 from the lower 3 bits of the step in the predetermined excitation pattern shown in FIG. 4 (S12). Next, the next interrupt time is set in TSPD (S13). This gives T
The drive pulse is applied for a time of SPD = 2.000 ms. Then, the current position of the step motor, step S
TEP becomes ST2.

In the case of ST2, DSTEP = 9-2 =
4. Since MSPD = 1, the speed is increased to MSPD = 2 (S3), the excitation time 1.429 ms corresponding to MSPD = 2 shown in FIG. 5 is read and stored as TSPD (S5). Next, the TSP at CMOVE = 2.000 ms
Adding D = 1.429 ms, CMOVE = 3.42
It is set to 9 ms (S6). Next, since MSPD = 2, a drive pulse having a drive frequency of 700 pps is given according to FIG. 5 (S12). Next, set the next interrupt time to TSPD
(S13). As a result, TSPD = 1.
The drive pulse is applied for a time of 429 ms. Then, the current position step STEP of the step motor is ST
It will be 3.

In the case of ST3 to ST8, the description is omitted because it is the repetition of the above case. Where ST4
Up to ST5, constant speed is maintained in ST5, ST
In 6 to ST8, deceleration is being performed. In ST8, CMOVE = 2.000 + 1.429 + 1.186
+ 1.040 + 1.040 + 1.186 + 1.429 +
2,000 = 11.31. Next, the flow in ST9 will be described. FLG = 0 and (S1, YE
S), STEP is updated and STEP is a target step
= 9 (S2), decelerating and setting MSPD = 0 (S2)
3). Since MSPD = 0 (S4, YES), the process proceeds to S7. CMOVE = 11.310 ms is a multiple region 10.2-14.10 with a period of 5.2-7.2 ms corresponding to the natural frequency of the step motor 15 that drives the throttle valve.
Since it is included in 4 ms (S7, YES), it is determined that resonance is likely to occur (S7, YES), and the flag FLG for performing anti-phase excitation is set to 1 (S9). next,
Insert TR1 into TSPD (S10). In this embodiment, T
R1 = 1.0 ms. Next, CMOVE is cleared to 0 (S11).

Next, the step motor 15 has MSPD = 0.
Is excited by TSPD = 1.0 ms (S12). Then, after TSPD = 1 ms, the process proceeds to S1 by an interrupt.
Next, since FLG = 1 (S1, NO; S14, YE
S) and STEP = 9 are updated one step in the reverse direction to set STEP = 8 (S15). Next, FLG is set to 2 (S16). Next, insert TR2 into TSPD (S
17). In this embodiment, TR2 = 1.0 ms. Next, the excitation in the state of step 8 is given to the step motor 15 as anti-phase excitation (S12). And
After 1.0 ms, the operation proceeds to ST1 by an interrupt.

Next, since FLG = 2 (S1, N
O; S2, NO), STEP = 8 in the forward direction 1
The step is returned (S18), and STEP = 9. Next, FLG is set to 0 (S19), and TR3 is put into TSPD (S20). In this embodiment, TR3 = 3.0 ms. Next, excitation of the target step is given to the step motor 15 by TSPD = 3.0 ms (S12). Then, after TSPD = 3.0 ms, the process returns to S1 by an interrupt. As a result, when the depression amount of the accelerator 26 changes, it is possible to quickly follow the next target value.

In this embodiment, the case where the anti-phase excitation is performed has been described. However, when the drive time does not match the multiple region of 5.2 to 7.2 ms, the oscillation is reduced by not performing the anti-phase excitation. Therefore, anti-phase excitation is not performed. In this embodiment, the driving time is the step motor 1
The period corresponding to the natural frequency of the drive system of No. 5 is 5.2 to
Although the case of matching with the double region of 7.2 ms has been described, the same applies to the case of 1 ×, 3 × or more as shown in FIG.

In this embodiment, the anti-phase excitation time TR2 is constant, but the anti-phase excitation time TR2 may be changed according to the magnitude of the vibration amplitude shown in FIG. In addition, considering the phase difference of damping due to the phase shift of vibration caused by FIG.
May be changed. In this embodiment, the anti-phase excitation has been described as the vibration reducing method, but the method of interrupting the current also exhibits exactly the same effect. The method of cutting off the current is well known from the publications cited in the prior art, and a detailed description thereof will be omitted.

As described in detail above, according to the step motor controller 17 of this embodiment, the step motor 1
The drive time of step motor 1 is counted by counting the drive time of 5
The period corresponding to the natural frequency of the drive system of No. 5 is 5.2 to
Since the anti-phase excitation is applied only when it coincides with the multiple region of 7.2 ms, the anti-phase excitation is not performed and new vibration is not generated when resonance does not occur. Therefore, the step motor 15 is stopped. Can be done quickly and accurately. As a result, the throttle valve 12 can be accurately controlled, and the amount of intake air to the gasoline engine 11 can be accurately controlled. Also, when the step motor 15 is stopped,
Since the vibration of the throttle valve 12 is small, the vibration at the time of stopping can be converged in an extremely short time. Therefore, even when the depression amount of the accelerator 26 is reversed from acceleration to deceleration, it is possible to quickly respond.

Although the present invention has been described with reference to some embodiments, the present invention is not limited to the above embodiments, and various modifications and improvements can be made without departing from the spirit of the present invention. This can be easily guessed.
In the present embodiment, the apparatus for sampling the target set value has been described, but it is natural that the present invention can be applied even when the step motor is stopped at the target set value given from the host computer or the like in the OA equipment.
Further, in the present embodiment, the control device of the step motor that drives the throttle valve has been described, but the present invention can be applied to the control of all step motors.

[0034]

As is apparent from the above description, according to the step motor control device of the present invention, the drive time for counting the drive time from when the step motor is driven to when the step motor is stopped at the set target value is calculated. Counting means, resonance determining means for determining resonance occurrence when the drive time matches a multiple of the cycle corresponding to the natural frequency of the drive system of the step motor, and when the resonance determining means determines resonance occurrence, step Since it has a vibration reducing means for performing control for reducing vibration when the motor is stopped, vibration is reduced only when there is a possibility of resonance, and there is no possibility of resonance occurring. Sometimes, new vibration is not generated, so the step motor can be stopped quickly and accurately, and the throttle valve can be stopped quickly and accurately. It can be controlled amount of the intake accurately. Further, even if the accelerator depression amount is reversed, it can be promptly dealt with.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a step motor control device that is an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a control state of a step motor controlled by the step motor control device.

FIG. 3 is a flowchart showing an operation of the step motor control device.

FIG. 4 is a data diagram showing an excitation pattern of a step motor.

FIG. 5 is a data diagram showing drive pulses for acceleration / deceleration of a step motor.

FIG. 6 is an experimental data diagram showing the amplitude of vibration when the step motor is stopped.

FIG. 7 is an explanatory diagram showing a control state of a step motor controlled by a conventional step motor control device.

[Explanation of symbols]

 12 Throttle Valve 15 Step Motor 16 Potentiometer 17 Step Motor Control Device 18 Drive Circuit 19 CPU 20 A / D Converter 24 Sampling Program 25 Step Motor Acceleration / Deceleration Program 27 Resonance Discrimination Program 28 Reverse Phase Excitation Program 29 Drive Time Counting Program 29

Claims (3)

[Claims] 1. A sampling means for sampling a set target value for stopping a step motor, a difference between the sampled set target value and the current position of the step motor is calculated, and the step motor is accelerated according to the difference. In a step motor control device having a step motor acceleration / deceleration means for decelerating the step motor when approaching the set target value and stopping the step motor at the set target value, the step motor is stopped at the set target value after being driven. A drive time counting means for counting the drive time until, and a resonance determining means for determining the occurrence of resonance when the drive time matches a multiple of the cycle corresponding to the natural frequency of the drive system of the step motor, If the resonance determination means determines that resonance has occurred, a control is provided to reduce vibration when the step motor is stopped. Step motor control apparatus characterized by comprising a vibration reducing means for performing. 2. The device according to claim 1, wherein the vibration reducing means temporarily interrupts a current at a target step supplied to the step motor, and a step immediately before the target step supplied to the step motor. A step motor control device, characterized in that it is either a means for temporarily interrupting a current or a means for temporarily exciting a reverse phase current to a step motor. 3. The step motor control according to claim 1 or 2, wherein a cycle corresponding to the natural frequency of the drive system of the step motor is 5.2 to 7.2 ms. apparatus.