JPH09327197A - Method and device for controlling motor actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the deviation in driving position as small as possible by storing a phase a predetermined value before a driving phase at the stopping of operation and restarting the operation from the stored driving phase. SOLUTION: When a control is started, it is judged whether the supply voltage is within a predetermined range or not. In the case that the supply voltage is below the specified range, it is judged that the supply voltage is abnormal and then it is judged whether a motor actuator is being driven or not. When the motor actuator is being driven, the operation is stopped and the data about a driving step at the stopping of operation is stored as a variable S1 is a memory built in a CPU. After that, '1' is subtracted from the stored value and then the calculated value is stored as a new value of the variable S1. Then, on the assumption that there is a deviation in position of the stepping motor, a variable 'm' for obtaining an estimated value S for the deviation in position of the stepping motor is set to '1' and the variable 'm' is added to the estimated value S for the deviation in position at this point of time and then the up-to-date estimated value S for the deviation in position is obtained. When starting the operation again, the operation is restarted from the driving step stored as the variable S1. By this method, the deviation in position can be lessened to the utmost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor actuator using a stepping motor, and more particularly to various doors such as intake doors and air mix doors for switching the flow of air in a vehicle air conditioner. The present invention relates to a method for controlling a motor actuator used for rotating and an improved control device therefor.

[0002]

2. Description of the Related Art Various types of control devices for motor actuators using stepping motors, which are used to rotate various air conditioning doors in a vehicle air conditioning system, have been proposed in the past (for example, special features). Fairness 4-9
685, etc.).

[0003]

In order to control the operation of a motor actuator using such a stepping motor, so-called open-loop control is often used because of its simple structure, and in recent years, so-called open loop control has been used. Most of them are configured to be controlled by using a microcomputer, but the open control by such a microcomputer has the following problems.

That is, for example, if a so-called key off is performed during driving of a stepping motor which constitutes a motor actuator of a vehicle air conditioner, the power supply to the stepping motor is cut off at substantially the same time as the key off. The stepping motor is immediately stopped. On the other hand, an electrolytic capacitor having a relatively large capacity is generally used in the power supply circuit of the microcomputer, and therefore the power supply voltage of the microcomputer is different from the power supply voltage of the stepping motor immediately even if the key is turned off. The potential does not drop to a state in which the operation of the microcomputer is stopped, but the potential decreases exponentially.

Usually, in a microcomputer used in such a vehicle air conditioner, the power supply voltage applied to the microcomputer is regularly monitored, and the power supply voltage is at a predetermined value (the microcomputer operates completely). The voltage is higher than the voltage at which the power supply is stopped, and the power supply voltage is in an abnormal state, and the necessary processing can be performed
When the following is detected, the microcomputer stops outputting the drive signal to the stepping motor and stores the information on the drive position of the stepping motor at that time.

Therefore, as described above, when the key is turned off during the driving of the stepping motor, the power supply voltage becomes the predetermined value or less for a short time even after the operation of the stepping motor is stopped, that is, by the microcomputer. Until it is detected, the microcomputer continuously outputs the drive signal to the stepping motor, and the output of the drive signal is stopped only when the power supply voltage is detected to be equal to or lower than a predetermined value. The driving position of the stepping motor at that time is stored in the microcomputer, and the operation of the microcomputer is stopped.

Therefore, the actual stop position of the stepping motor differs from the position stored in the microcomputer, and when the power is turned on again and the stepping motor is activated by the microcomputer, the microcomputer stores the data. Since the stepping motor is driven based on the obtained position information, when the key-off as described above is repeated, a deviation between the actual driving position of the stepping motor described above and the driving position stored in the microcomputer occurs. There is a problem in that, after being accumulated, a non-negligible difference occurs between the desired position and the actual position of the air conditioning door at the end.

The above-mentioned problem does not occur only when the key is turned off, but also when the power supply voltage drops for some reason. That is, when the power supply voltage is monitored by the microcomputer, if it is detected that the power supply voltage becomes abnormal due to some cause other than key-off and falls below a predetermined value, the microcomputer sends a signal to the stepping motor. Although the output of the drive signal is stopped, there is a response delay until the microcomputer detects an abnormality in the power supply voltage and stops the output of the drive signal to the stepping motor. The power supply voltage may be so low as to stop the operation of the stepping motor when the stop is performed. For this reason,
The position where the driving of the stepping motor is actually stopped,
A deviation from the position stored in the microcomputer will occur, and upon re-driving, the same problem as in the case of the key-off described above will occur.

The present invention has been made in view of the above circumstances, and is a motor capable of minimizing the deviation of the drive position of the stepping motor caused by the fluctuation of the power supply voltage, the delay of the control response, and the like. An actuator control method and a control device thereof are provided. Another object of the present invention is to provide a motor actuator control method and a control device therefor capable of reducing the number of times of so-called origin reset of a stepping motor constituting a motor actuator with a relatively simple structure. It is in.

[0010]

According to a first aspect of the present invention, there is provided a method of controlling a motor actuator, which detects a variation in a power supply voltage, and detects a variation in a predetermined power supply voltage.
The driving of the motor actuator including the stepping motor is stopped, and the phase before the predetermined value of the driving phase when the driving of the stepping motor is stopped is stored, while the power supply voltage is determined to be normal and the driving of the stepping motor is restarted. At this time, the driving of the stepping motor is started from the stored driving phase.

In such a method, when the stepping motor is driven and controlled by, for example, a CPU, when the power supply voltage falls below a predetermined value and the driving of the stepping motor is stopped, the stepping motor is actually driven by a so-called response delay of the CPU. This is done by paying attention to the operation of the conventional device in which the drive phase when the drive is stopped and the drive phase stored in the CPU are different. The power supply becomes normal and the stepping motor is restarted. At this time, the drive phase for the stepping motor is set to a phase that is a predetermined value before the drive phase when the CPU stops driving the stepping motor first, so that the positional deviation due to the response delay as described above can be eliminated. It is a thing.

A motor actuator control device according to a second aspect of the present invention is a motor actuator control device comprising drive means for driving a stepping motor constituting a motor actuator based on a control signal input from the outside. A power source determining means for determining an application state of the power source voltage; and, when the power source determining means detects a predetermined decrease in the power source voltage, stops the operation of the driving means and causes the driving means to stop the operation. The drive stop control means for storing a phase before the drive phase of the stepping motor by a predetermined value, and the drive when the power supply voltage is determined to be normal by the power supply determination means and the stepping motor drive start is externally instructed. The phase of the drive start of the stepping motor by the means is controlled by the drive stop control means. A drive start control means for controlling the operation of said driving means to be a 憶 been driven phase is made comprises a.

In such a configuration, each means can be realized mainly by executing software by a so-called CPU. In this device, when the stepping motor is driven and controlled by the CPU, for example, when the power supply voltage becomes a predetermined value or less and the driving of the stepping motor is stopped, the stepping motor is actually driven by a so-called response delay of the CPU. This is done by paying attention to the operation of the conventional device in which the drive phase when it is in the stopped state and the drive phase stored in the CPU are different. For example, when the power switch is opened and the power supply is determined by the power supply determination means. When a predetermined decrease in voltage is detected, the drive stop control means stops the driving of the stepping motor. At this time, the phase that is a predetermined value before the drive phase at the time of stop is stored. Then, when the power switch is turned on and the power supply determining unit determines that the power supply voltage is normal, when the driving of the stepping motor is started, from the phase stored in the drive stop control unit as the drive phase, The operation of the drive means is controlled by the drive start control means so that the drive of the stepping motor is started by the drive means, and therefore the positional deviation due to the response delay as described above is eliminated. It is a thing.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The members, arrangements, and the like described below do not limit the present invention and can be variously modified within the scope of the gist of the present invention. First, a schematic configuration of a vehicle air conditioner to which the present invention is applied will be described with reference to FIG.

The upstream side of the air conditioning duct 1 of the vehicle air conditioner is branched into an outside air introducing port 2 and an inside air introducing port 3, and the branching portion is for selecting the air to be introduced into the air conditioning duct 1. An intake door 4 is provided.

A blower motor 5, an evaporator 6 and a heater core 7 are sequentially arranged on the downstream side of the air conditioning duct 1. The evaporator 6 constitutes a cooling cycle together with a compressor and a condenser (not shown).

The heater core 7 is provided on one side of the air conditioning duct 1 in a biased manner, a bypass passage 10 is formed between the other side wall of the air conditioning duct 1 and the heater core 7, and in front of the heater core 7. An air mix door 11 for adjusting the amount of air passing through the heater core 7 and the amount of air passing through the bypass passage 10 is provided.

Further, on the downstream side of the air conditioning duct 1, a vent outlet 12, a defrost outlet 13 and a heat outlet 1 are provided.
It is formed so as to be divided into four parts and opens into a vehicle interior (not shown), and mode doors 15a and 15b are provided at the respective outlets.

The intake door 4, the air mix door 11, and the mode doors 15a and 15b described above can all be changed in rotational position by a motor actuator using a stepping motor (not shown). That is, the intake door 4 is operated by the motor actuator 16, the air mix door 11 is operated by the motor actuator 17, and the mode doors 15a and 15b are operated.
Are respectively driven by the motor actuators 18.

The control unit 19 is provided with, for example, the above-mentioned motor actuators 16, in order to obtain an air-conditioning state according to the setting of various operation switches of the control panel 20 provided on an instrument panel (not shown) in the vehicle compartment. The operation control of 17, 18, the blower motor 5 and the like is performed. The control unit 19
Is connected to a battery 23 via an ignition switch 21 and an accessory switch 22. One terminal of the ignition switch 21 (a terminal on the side connected to the control unit 19) is connected to each motor actuator 16 , 17, 18 is connected to one of the terminals for applying power to a stepping motor (not shown).

The motor actuator control apparatus according to the embodiment of the present invention is the above-described motor actuator 1.
It is used for Nos. 6, 17 and 18, and is realized by executing software in the control unit 19, as described later. 2 to 6 below
The control procedure by the motor actuator control device will be described with reference to FIG. First, the contents of the control procedure in the main routine shown in FIG. 2 will be described with reference to FIG.

The control unit 19 has a battery 23 when the accessory switch 22 is closed.
It is activated by receiving power supply from. Then, in the control unit 19, it is determined whether or not the ignition switch 21 is closed (ON), and whether or not the closing is the first one after the operation of the control unit 19 is started. If it is determined that the ignition switch 21 is closed for the first time (YES), the process proceeds to step 102, and it is determined that the ignition switch 21 is not closed for the first time. If the answer is NO (NO), the process proceeds to step 104.

At step 102, each door 4, 1
It is determined whether or not the positional deviation estimated value S (details described later) indicating the possibility of positional deviation of 1, 15a, 15b exceeds a predetermined value K, for example, a value appropriately selected between 30 and 60, If it is determined that the doors have been exceeded (YES), the doors 4, 11, 15a, and 15b are misaligned by a predetermined amount or more, and it is determined that the initial position of the doors needs to be set. Then, the initial position of the door is set (see steps 102 and 106 in FIG. 2).

That is, in this step 106, it is determined that the position deviation estimated value has exceeded the predetermined value as described above in any of the intake door 4, the air mix door 11 and the mode doors 15a and 15b as described above. If the door is judged as such,
The stepping motor is subjected to a predetermined drive control by the control unit 19 so that the door position is initialized (reset) so as to reach a predetermined initial setting position. After the processing of step 106, other processing (not shown) is performed as necessary to return to the first processing of the main routine, and a series of processing is repeated.

On the other hand, when it is determined in step 102 that the positional deviation estimated value S (details will be described later) has not exceeded the predetermined value K, normal control is performed (see step 104 in FIG. 2). . That is, the control unit 19 controls the operation of the motor actuators 16 to 18 and circuits (not shown) for air conditioning control. It should be noted that the processing such as the calculation of the position deviation estimated value S and the drive control with respect to the fluctuation of the power supply voltage are performed by one subroutine processing in step 104.

FIG. 3 shows a subroutine flow chart showing the contents of the subroutine processing for the calculation of the position deviation estimated value S in the motor actuator control and the drive control for the fluctuation of the power supply voltage. The contents will be explained while doing so. When the control is started, it is first determined whether the power supply voltage is within a predetermined range (see step 200 in FIG. 3).

If it is determined that the power supply voltage is, for example, 9 V or more, it is determined as normal and step 2 described later
On the other hand, if it is determined that the voltage is less than 9v, the motor actuator 16
It will be determined whether or not each of the .about.18 is being driven (see step 202 in FIG. 3). In addition, in FIG. 3, "ACT"
Means a motor actuator. Then, when it is determined that the motor actuators 16 to 18 are not driven (in the case of NO), the process proceeds to step 218 described later, while it is determined that the motor actuators 16 to 18 are being driven (YES. In this case), the driving of the motor actuators 16 to 18 is stopped (see step 204 in FIG. 3).

Next, a drive step as a drive phase output from the control unit 19 to the motor actuators 16 to 18 when the drive of the motor actuators 16 to 18 is stopped is stored in a built-in memory of a CPU (not shown) in the control unit 19. Data (indicated as "current STEP" in step 206 of FIG. 3) is stored as a variable S1 (step 2 of FIG. 3).
06).

Further, "1" is subtracted from the value stored in the variable S1 as described above, and the result of the subtraction is again used as the value of the variable S1 (see step 208 in FIG. 3).
Then, due to this abnormal power supply voltage, each door 4, 11,
Assuming that so-called misalignment of 15a and 15b occurs,
The value of the variable m for obtaining the position deviation estimated value S, which is an index of the number of times the position deviation of the stepping motor has occurred, is set to "1" (see step 210 in FIG. 3).

Then, the value of the variable m is added to the value of the positional deviation estimated value S at this point to calculate the latest positional deviation estimated value S (step 212 in FIG. 3).
reference). After this step 212, other processing (not shown) is performed as necessary, the series of sub routine processing is ended, and the process returns to the main routine.

On the other hand, when it is determined in the previous step 200 that the power supply voltage is 9 V or higher, it is determined in step 214 whether or not the motor actuators 16 to 18 are in the driving state. . Whether or not the motor actuators 16 to 18 are driven is determined according to the air-conditioning state in another subroutine process (not shown) in the normal control in the main routine. It is a thing.

When it is determined that the driving is unnecessary (NO
If it is determined that the drive is necessary (YES), the variable S1 set in step 208 described above is set.
From the drive steps stored in the motor actuator 1
The driving of the stepping motors 6 to 18 is started (see step 216 in FIG. 3). That is, in this case, when the stepping motor is stopped by the control unit 19 in advance, the driving step temporarily stored as the current STEP (corresponding to the phase state of the driving pulse signal at the time of starting the driving of the stepping motor) ), The driving is started from the driving step immediately before that (calculated in step 208).

In this case, the value of the variable m is set to "0" on the assumption that there is no displacement (step 21 in FIG. 3).
8), the process proceeds to step 212 described above. Therefore, in this case, the positional deviation estimated value S does not increase in step 212, and the previous value is held.

Here, when the driving of the stepping motor is started as described above, the significance of starting the driving from the step immediately before the driving step when the driving is stopped will be described with reference to FIGS. 4 to 6. While explaining. First, an example of driving a stepping motor will be described with reference to FIG. As a premise, one end of an exciting coil (not shown) for each phase of the stepping motor is connected in common (in FIG. 4, this connection point is referred to as “COM”), and the drive pulse is connected. While the positive side of the signal is applied (indicated as “+” in FIG. 4), the other side of the exciting coil of each phase is the reference of the drive pulse signal according to the control of the control unit 19. It is assumed that a ground potential, which is a potential, is applied. Under such a premise, FIG. 4 shows a state of applying a signal to the other end side of the exciting coil of each phase in each step.

In the case of the drive example shown in FIG. 4, the drive is basically such that the phase of the drive pulse applied for each phase is shifted by one step regardless of the rotation direction. For example, when the rotation direction of the stepping motor is set to the normal rotation direction, the drive pulse is applied to the first phase during the first and second steps, and during the second step,
A drive pulse is applied to the second phase at the same time, and a drive pulse is applied to the second phase also in the third step. In the third step, the drive step is also applied to the third phase. Is applied, the drive pulse is applied to the third phase in the fourth step, the drive pulse is also applied to the fourth phase in the fourth step, and the fourth phase is further applied in the fifth step. Drive pulse is also applied, and in the fifth step, the drive pulse is applied to the first phase as well, so that it is cyclically applied to each exciting coil (not shown) of the first to fourth phases. A drive pulse is applied.

When the rotation direction of the stepping motor is set to the reverse direction, the drive pulse is applied from the fourth phase to the first phase at the same timing as described above contrary to the case of the normal rotation described above. Becomes When such driving is performed on the stepping motor, in the conventional device,
For example, when the power supply to the stepping motor is cut off while driving the stepping motor and the power supply is restarted after the driving of the stepping motor is stopped, the starting state of the stepping motor is determined by the stepping motor. It is determined by the relationship between the step when the motor is stopped (see FIG. 4) and the step in which the CPU stops driving the stepping motor and the step stored in the CPU at that time.

FIG. 6 illustrates the result of testing in a conventional device what operation the stepping motor will take after the power is restored, assuming that the stepping motor has stopped in the state of step 1 in the above case. FIG. The result will be described below with reference to the same figure. First, when the step "2" is stored in the CPU (not shown), the "start of excitation step recognized by the CPU" in FIG. (See the column), when the power is turned on again,
The stepping motor starts to rotate synchronously in one step forward (see the column of "ACT initial behavior" in Fig. 6 (1)), and in this case, the deviation amount becomes zero (Fig. 6 ( (Refer to the column of "Displacement amount" in 1)). The frequency of occurrence of such a state is relatively high (see the column of “frequency of occurrence” in FIG. 6 (1)).

Next, when step "3" is stored in the CPU (see "Excitation start step recognized by CPU" column in FIG. 6 (2)), stepping when the power is turned on again The initial behavior of the motor can occur in one of two operating states: a case where the motor rotates synchronously after two steps of normal rotation (the former) and a case where the motor rotates synchronously after two steps of reverse rotation (the latter). (See the column of "ACT initial behavior" in FIG. 6 (2)). In this case, the deviation amount is zero in the former case and 4 steps in the latter case (“deviation amount” in (2) of FIG. 6).
Column). Further, the frequency of occurrence of such a state is relatively high as in the case described above (see the column of “frequency of occurrence” in FIG. 6 (2)).

Further, when the step "4" is stored in the CPU (see the column of "Excitation start step recognized by the CPU" in FIG. 6 (3)), the stepping motor when the power is turned on again. The initial behavior of is reversed instantaneously for one step and then becomes synchronous rotation (see "ACT initial behavior" in Fig. 6 (3)).
6), the shift amount in this case is 4 steps (see the “shift amount” column in FIG. 6C). Further, such a state is considered as one of the possible operating states, but the actual occurrence frequency is extremely low (see the "occurrence frequency" column in FIG. 6 (3)).

Based on the above test results, the inventor of the present application found that when the stepping motor is stopped, the power is turned on again and the CPU starts driving the stepping motor, the steps at the time when the stepping motor is stopped , The difference from the step output from the CPU to the stepping motor can be synchronized up to about one step, but 2
It was concluded that there is a high possibility that synchronization may not be possible if the number of steps exceeds.

In addition to the above conclusions, the inventor of the present invention determines that the power supply voltage has dropped and stops the drive signal to the stepping motor in the actual device, for example, when the driving cycle of the stepping motor is 250 PPS. It is stored in the CPU when restarting the driving of the stepping motor in consideration of the fact that up to 3 steps are counted up to a maximum and the value may be stored in the CPU as a step when the driving is stopped. If we start from the step before the step, we think that a good re-driving state can be obtained,
As a result of the test, good results could be obtained. Figure 3 above
The control described in 1) is based on such test results.

An example of a concrete test result will be described with reference to FIG. 5. First, this test result shows various C
It shows the result when the driving step at the start of driving as described above is driven as one step before the step stored in the CPU with respect to the storage step of the PU. That is, when the step stored in the CPU is "1" (see the "Excitation start step recognized by the CPU" column in Fig. 5 (1)), the stepping motor causes the rotor (Not shown) becomes so-called held and stopped, and then becomes a synchronous rotation state (see the column of “ACT initial behavior” in FIG. 5 (1)), and the deviation amount at that time is zero ( (Refer to the column of "deviation amount" in FIG. 5A). The frequency of occurrence of such cases is relatively high (FIG. 5).
(Refer to the column of “occurrence frequency” in (1)).

When the step stored in the CPU is "2" (see the "Excitation start step recognized by the CPU" column in FIG. 5B), the stepping motor is not operated when the drive is restarted. After one step of forward normal rotation, a synchronous rotation state is entered (see the column of "ACT initial behavior" in Fig. 5 (2)), and the deviation amount at that time is zero (Fig. 5 (2)). (Refer to the column of "deviation amount"). The frequency of occurrence of such cases is relatively high (see the "frequency of occurrence" column in FIG. 5 (2)).

Further, when the step stored in the CPU is "3" (see the column "Excitation start STEP recognized by the CPU" in FIG. 5 (3)), the stepping motor at the start of driving is The initial behavior can occur in two cases, that is, a case where two steps are normally rotated and then a synchronous rotation state is generated, and a case where two steps are reversed and a synchronous rotation state is generated (FIG. 5).
(Refer to the column of "ACT's initial behavior" in (3)). And the displacement amount in this case was zero in the former case,
In the latter case, there were 4 steps (see the column of "deviation amount" in FIG. 5 (3)). The frequency of occurrence in this case is extremely low (see the column of “frequency of occurrence” in FIG. 5 (2)).

As described above, when the stepping motor is re-driven, the driving is started from the step immediately before the step stored in the CPU, so that the actual step when the stepping motor is stopped and the CPU Even if there is a difference from the step at the time of stopping the driving stored in, it is possible in most cases to set the deviation to zero and bring the stepping motor into the driven state again.

In the control shown in FIG. 3, the CP is set when the driving of the stepping motor is started or stopped.
The reason why the driving is started from the step immediately before the step stored in U is based on the test result as described above. Particularly, the processing of steps 206 and 208 causes the stepping motor of the CPU to operate. The step immediately before the step at the time of driving stop is stored, and step 2
By the processing of 00, 214, and 216, when the power is normally turned on again, the driving is started from the step stored as described above.

In the above-described embodiment of the invention, when the stepping motor is restarted, the step "1" starts when the CPU stops driving the stepping motor.
Although the driving is performed from the subtracted step, the subtraction amount is not necessarily limited to "1" and should be appropriately set according to the number of phases of the stepping motor, the driving speed, and the like.

In the embodiment of the invention described above, the drive means is the control unit 19 shown in FIG.
By executing step 104 shown in FIG. 3, the power supply determining means is realized by executing the steps 200 and 214 shown in FIG. 3 by the control unit 19, respectively. Further, the drive stop control means includes steps 202 and 20 shown in FIG. 3 by the control unit 19.
4, 206 and 208, the drive start control means is realized by the control unit 19 executing steps 214 and 216 shown in FIG.

[0049]

As described above, according to the present invention,
By configuring so that the difference between the actual stop position of the stepping motor and the drive stop position for the stepping motor stored in the CPU is eliminated when the stepping motor is restarted, the so-called on / off of the power source and , Each time the stepping motor is restarted when the power supply voltage drops below a predetermined value and returns again,
Since it is surely avoided that the difference between the actual stop position of the stepping motor and the drive stop position for the stepping motor stored in the CPU is accumulated.
A so-called misalignment can be minimized and a highly reliable device is provided.

Further, since the occurrence of displacement is reduced,
It is possible to reduce the frequency of so-called origin resetting. Therefore, the noise that may occur at the time of origin resetting, for example, the frequency of the abnormal noise generated when the air-conditioning door is pressed against the so-called seat position is reduced, and comfort is reduced. It is possible to improve the sex. Furthermore, since the detection of the fluctuation of the power supply voltage is normally performed in the vehicle air conditioner, it is possible to use the result, and even if it cannot be used as it is, the software It is possible to respond sufficiently by additions, changes, etc.
Since no special circuit is additionally required, the structure is simplified and the cost of the device can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration example of a vehicle air conditioner to which a motor actuator control device according to the present invention is applied.

FIG. 2 is a main flowchart showing a procedure of main control executed by a control unit of the vehicle air conditioner shown in FIG.

FIG. 3 is a subroutine flowchart showing a procedure of a subroutine process for motor actuator control executed in the main control described with reference to FIG.

FIG. 4 is an explanatory diagram illustrating an example of driving a stepping motor.

FIG. 5 is an explanatory diagram for explaining the behavior of the stepping motor at the start of driving when the stepping motor is driven again after the power is cut off in the conventional device.

FIG. 6 is an explanatory diagram for explaining a test result of motor actuator control according to the embodiment of the present invention.

[Explanation of symbols]

 4 ... Intake door 11 ... Air mix door 15a, 15b ... Mode door 16-18 ... Motor actuator 19 ... Control unit 21 ... Ignition switch 22 ... Accessory switch

Claims (4)

[Claims] 1. A change in power supply voltage is detected, and when a predetermined change in power supply voltage is detected, driving of a motor actuator including a stepping motor is stopped, and a predetermined drive phase is set when the drive of the stepping motor is stopped. While the phase before the value is stored, when the power supply voltage is determined to be normal and the drive of the stepping motor is restarted, the drive of the stepping motor is started from the stored drive phase of the motor actuator. Control method. 2. A motor actuator control device comprising a driving means for driving a stepping motor constituting a motor actuator based on a control signal inputted from the outside, and a power supply judging means for judging an application state of a power supply voltage. When a predetermined decrease in the power supply voltage is detected by the power supply determination means, the operation of the drive means is stopped, and a phase that is a predetermined value before the drive phase of the stepping motor by the drive means when the operation is stopped. A drive stop control unit that stores the power supply voltage is determined to be normal by the power supply determination unit, and when the drive start of the stepping motor is instructed from the outside, the phase of the drive start of the stepping motor by the drive unit is The operation of the drive means is controlled so that the drive phase is stored by the drive stop control means. And a drive start control unit for controlling the motor actuator. 3. The motor actuator control device according to claim 2, wherein the predetermined decrease of the power supply voltage is caused by opening of a power supply switch. 4. The motor actuator control device according to claim 2, wherein the predetermined decrease in the power supply voltage is due to a change in the power supply voltage when the power switch is closed.