JPH07303397A - Step motor excitation coil disconnection diagnostic device - Google Patents

Abstract

(57) [Summary] [Purpose] Energizing state of each exciting coil (state of drive signal)
Enables disconnection diagnosis without detecting [Structure] For a plurality of exciting coils (# 1 to # 4), drive signals C # 1 to C # 4 are changed at a constant cycle (10 ms) according to a predetermined pattern, and one step is changed for each change. When the rotation is obtained, the check signals C # 1 to C # are set to the H level only when the drive signals D # 1 to D # 4 are at the L level and there is no disconnection for each exciting coil.
Derive 4 And the cycle that changes by one step (10m
s) check signals C # 1 to C # with a cycle (2 ms) shorter than
4 is sampled and the history of H level is stored. Then, at every predetermined step (4 steps), the presence or absence of disconnection is diagnosed based on the H-level history during that time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a step motor excitation coil disconnection diagnostic device.

[0002]

2. Description of the Related Art Conventionally, an idle speed control valve (I) provided in an auxiliary air passage bypassing an intake passage (throttle valve) has been used for controlling an idle speed of an engine.
(SC valve) and a purge control valve provided in the purge passage in order to purge the evaporated fuel from the canister that has adsorbed the evaporated fuel from the fuel tank into the intake passage, there are those that are driven by a step motor. .

Such a step motor is provided with a plurality of exciting coils, and changes the energizing states of these exciting coils at a constant energizing cycle in accordance with a predetermined pattern, and obtains one step rotation each time the energizing state is changed. (See Japanese Patent Publication No. 2-63098).

[0004]

By the way, when such a stepping motor is used, when the exciting coil is broken, desired control becomes difficult. Therefore, it is necessary to detect this promptly and take countermeasures. is there. Therefore, energization / de-energization (driving signal ON / OF
It is possible to provide a check circuit for deriving a check signal that becomes a specific level only in one of the cases of F) and when there is no disconnection, and diagnose the presence or absence of disconnection of each excitation coil by the check signal from each check circuit. It is considered.

However, for this diagnosis, it is necessary to judge whether or not the check signal is appropriate with respect to the energization state (ON / OFF of the drive signal) of each exciting coil, and the exciting coil is driven by the main CPU. And input the check signal from the check circuit to another sub CPU,
Since it is difficult for the PU to detect the state of the drive signal, it has not been possible to make a diagnosis.

In view of such an actual situation, the present invention comprises a plurality of exciting coils, and changes the energizing states of these exciting coils at a constant energizing cycle according to a predetermined pattern,
In a step motor that obtains one step rotation each time the energized state is changed, it is possible to reliably diagnose whether or not the exciting coil is broken without detecting the energized state (drive signal state) of each exciting coil. An object of the present invention is to provide a disconnection diagnosis device for a motor exciting coil.

[0007]

Therefore, according to the present invention, as shown in FIG. 1, a specific level is set for each exciting coil only when either energized or de-energized and there is no disconnection. While a check circuit for deriving the check signal is provided, sampling means for sampling the check signal from each check circuit at a cycle different from an integral multiple of the energization cycle that changes by one step, and each check circuit sampled by this sampling means History storage means for storing the history of the check signal from each excitation coil,
If all of the plurality of exciting coils have no disconnection, when the check signals from all the check circuits change by a predetermined number of steps such that the check signals reach the specific level one or more times, the contents stored in the history storage means during that time are stored. A diagnostic means for diagnosing the presence or absence of disconnection based on the above is provided.

Alternatively, each exciting coil is provided with a check circuit for deriving a check signal which becomes a specific level only in the state of either energization or de-energization and when there is no disconnection, while energizing cycle changing one step. Sampling means for sampling the check signal from each check circuit in a shorter cycle, history storage means for storing the history of the check signal from each check circuit sampled by this sampling means for each exciting coil, and a plurality of excitation When all the coils have no disconnection, every time the check signals from all the check circuits change by a predetermined number of steps such that the check signal reaches the specific level once or more, the disconnection is made based on the stored contents of the history storage means during that period. And a diagnostic means for diagnosing the presence or absence of.

Here, the diagnosing means diagnoses that there is no disconnection when the history that the check signals from all the check circuits have reached the specific level is stored in the history storing means. Good. Further, it is preferable that the diagnosing means diagnoses a wire break when a state in which no wire break can be diagnosed continues for a predetermined number of times or more.

The history storage means stores, for each excitation coil, whether or not there is a history that the check signal from each check circuit sampled by the sampling means has reached the specific level. It is preferable to have a clear means for clearing the stored contents immediately after the diagnosis by the diagnosis means. Further, the sampling means, history storage means, and diagnostic means are provided in a sub CPU other than the main CPU that controls the energization state of the plurality of exciting coils, and the sub CPU outputs step position information from the main CPU.
The configuration may be such that the diagnostic means on the sub CPU side detects the diagnostic time each time it changes by a predetermined number of steps or more based on this step position information by transferring to the PU.

[0011]

In the above structure, the check signal from each check circuit is sampled at a cycle different from an integral multiple of the energization cycle that changes by one step (that is, the energization cycle in which the pattern of the energized state changes). Therefore, if all of the plurality of exciting coils have no disconnection, when the check signals from all the check circuits have changed by a predetermined number of steps such that the check signals have reached the specific level once or more, if each exciting coil has no disconnection, At least 1 for each excitation coil
The check signal of a specific level should be sampled once.

Accordingly, the history of the sampled check signals from the respective check circuits is stored for each exciting coil, and when the number of steps changes by a predetermined number or more, the presence or absence of disconnection is diagnosed based on the history of the check signals during that period. Of. Alternatively, the check signal from each check circuit is sampled at a cycle shorter than the energization cycle that changes by one step (that is, the energization cycle in which the pattern of the energized state changes), so that at least one check is performed every time the pattern of the energized state changes The signal can be sampled.

Therefore, if all of the plurality of exciting coils have no disconnection, the check signals from all the check circuits are 1 for each.
Whenever each exciting coil has no disconnection every time the number of changes exceeds the predetermined number of steps to reach the specific level more than once, the check signal of the specific level should be sampled at least once for each exciting coil. Therefore,
The history of the sampled check signals from the respective check circuits is stored for each exciting coil, and every time the number of steps changes by a predetermined number or more, the presence or absence of disconnection is diagnosed based on the history of the check signals during that period.

Specifically, it is diagnosed that there is no disconnection when the history that the check signals from all the check circuits have reached a specific level is stored. Although it may be diagnosed as an immediate disconnection at other times, it is possible to prevent an erroneous diagnosis by diagnosing a disconnection when the state in which it cannot be diagnosed as no disconnection continues for a predetermined number of times or more.

When the history of the check signal is stored, it may be stored in time series, but only the presence or absence of the history that the check signal has reached a specific level is stored, and the stored contents are stored immediately after the diagnosis. If cleared, the storage capacity can be reduced. Furthermore, the step position information is sent to the sub CP from the main CPU that controls the energization state of the plurality of exciting coils.
It is possible to correctly detect the diagnosis timing by transferring to U and detecting the diagnosis timing every time the predetermined number of steps changes by the diagnosis means on the sub CPU side based on the step position information.

[0016]

EXAMPLE An example of the present invention will be described below. Figure 2
Shows a unipolar two-phase simultaneous excitation type step motor drive circuit. The step motor 1 includes a rotor 2 connected to a rotating shaft and a pair of stators 3 and 4 fixedly arranged around the rotor 2. The stator coils of the stators 3 and 4 are wound in the same direction in the drawing. Has been done. Further, in the figure, winding start terminals of each stator coil are indicated by S ₁ and S ₂ , and winding end terminals are indicated by E ₁ and E ₂ . Further, in the figure, the intermediate taps of each stator coil are indicated by M ₁ and M ₂ .

In the stator 3, the stator coil between the winding start terminal S ₁ and the intermediate tap M ₁ forms a one-phase excitation coil # 1, and the stator coil between the winding end terminal E ₁ and the intermediate tap M ₁ is formed. Form a three-phase excitation coil # 3. In the stator 4, the stator coil between the winding start terminal S ₂ and the intermediate tap M ₂ forms a two-phase excitation coil # 2, and the stator coil between the winding end terminal E ₂ and the intermediate tap M ₂ is The 4-phase exciting coil # 4 is formed.

Each exciting coil # 1 to # 4 has an intermediate tap M.
_The winding start terminals S ₁ and S are connected to the power source VB on the side of ₁ and M _2.
2 or the winding end terminals E ₁ and E ₂ are grounded via driving transistors Tr _{1 to} Tr ₄ , respectively. As shown in FIG. 3, the base terminals of the transistors Tr _{1 to} Tr ₄ are connected to the drive terminals of the main CPU 10, and when the drive signals D # 1 to D # 4 from these drive terminals are at the H level. each transistor Tr ₁ to Tr ₄ is turned oN (conductive state), and is energized to the exciting coils # 1 to # 4 in.

Here, the drive signals D # 1 to D # 4 are changed as shown in FIG. That is, two phases are excited every 10 ms, and (1) 1-phase excitation coil # 1 and 4-phase excitation coil # 4, (2) 1-phase excitation coil # 1 and 2-phase excitation coil #
2, (3) 2-phase exciting coil # 2 and 3-phase exciting coil # 3,
(4) Repeat the four kinds of energized state patterns of the three-phase exciting coil # 3 and the four-phase exciting coil # 4 in sequence.
The drive signals D # 1 to D # 4 are changed.

As described above, the energization states of the exciting coils # 1 to # 4 are set at a constant energization period (10 m) according to a predetermined pattern.
In step s), each time the energized state is changed, one step rotation is obtained. On the other hand, each exciting coil # 1
# 4 from the connection point between the transistors Tr ₁ to Tr _4, the check circuit CK ₁ ~CK _4, the signal line is pulled out, thereby the check signal C # 1 through C # 4 is derived, As shown in FIG. 3, it is input to the sub CPU 20.

[0021] Here, as shown in FIG. 5, when the drive signals D # 1 to D # 4 for the exciting coils # 1 to # 4 (transistor Tr ₁ to Tr ₄₎ is H level, the exciting coils The check signals C # 1 to C # 4 are at the L level regardless of the presence or absence of disconnection of the # 1 to # 4.
When the drive signals D # 1 to D # ₄ for the ₁ to # 4 (transistors Tr1 to Tr4) are at the L level, if the exciting coils # 1 to # 4 are normal (no disconnection), check each The signals C # 1 to C # 4 are at the H level, and if disconnected, the check signals C # 1 to C # 4 are at the L level as indicated by the broken lines in the figure.

Therefore, each of the check circuits CK _{1 to} CK
₄ derives the check signals C # 1 to C # 4, which are at the H level only in the non-energized state (the drive signal is at the L level) and when there is no disconnection, for each of the exciting coils # 1 to # 4. If it is detected that the check signals C # 1 to C # 4 all have H level history, it can be diagnosed that there is no disconnection. Therefore, as shown in FIG. 6, the check signal C is set at a cycle different from an integral multiple of the energization cycle (10 ms) that changes by one step, and more preferably at a cycle (for example, 2 ms) shorter than the energization cycle (10 ms) that changes by one step. By sampling # 1 to C # 4, the check signals C # 1 to C # 4 can be sampled at least once every time the pattern of the energized state changes, and four steps (in the case of the two-phase simultaneous excitation method) Is more than 3 steps)
If there is no disconnection in 1 to # 4, each exciting coil # 1 to # 4
When the check signals C # 1 to C # 4 corresponding to the H level become the H level, the H level check signal should be sampled at least once each time.

Therefore, the history of the sampled check signals C # 1 to C # 4 is stored for each of the exciting coils # 1 to # 4, and every 4 steps change, the presence or absence of disconnection is determined based on the history between them. Make a diagnosis. Based on the above principle, the sub CPU 20 performs the disconnection diagnosis by executing the sampling routine (2 ms job) shown in FIG. 7 and the diagnostic routine (background job) shown in FIG.

The sampling routine of FIG. 7 will be described.
To do. This routine is a 2ms job and is executed every 2ms.
Be done. However, it does not have to be every 2 ms, and changes by one step
It may be executed in a cycle shorter than the energization cycle (10 ms).
In step 1 (indicated as S1 in the figure, and so on)
Is each check circuit CK ₁~ CK_FourCheck signal from
C # 1 to C # 4 are sampled and 4-bit sample
Ing data SOL.

Each bit of the sampling data SOL is, as shown in FIG. 9, a signal level H (=) of the check signals C # 1 to C # 4 corresponding to the drive coils # 1 to # 4.
1) and L (= 0), for example, C # 1 = 1,
When C # 2 = 0, C # 3 = 0, and C # 4 = 1, SOL
= 1001. This part corresponds to the sampling means.

In the next step 2, the 4-bit history data CHKDGN (initially CHKDGN = 0000) and the 4-bit sampling data SOL (for example, SOL = 1001) stored in the history storage RAM are stored in each bit. History data CHK is obtained by taking the logical sum (OR) for each
Update DGN. For example, CHKDGN = 0000
Then, when SOL = 1001, CHKDGN = 1 is newly added.
It becomes 001.

When CHKDGN = 1001, SOL
= 1100, CHKDGN = 1101 is newly set. Also, CHKDGN = 1110 and SOL = 011.
In the case of 0, CHKDGN = 1111 is newly set. Each bit of the history data CHKDGN updated in this way corresponds to each of the exciting coils # 1 to # 4 as shown in FIG. 10. For example, in the case of CHKDGN = 1001,
Check signals C # 1, corresponding to exciting coils # 1, # 4
C # 4 shows that it has a history of H level, and C # 4
When HKDGN = 1111, all exciting coils # 1
It is shown that the check signals C # 1 to C # 4 corresponding to # 4 to # 4 have an H level history.

Therefore, this portion corresponds to the history storage means. The diagnostic routine of FIG. 8 will be described. Note that this routine is executed as a background job. In the initialization routine when the power is turned on, STPMMMK =
It is assumed that 0, C _NG = 0, and F _NG = 0 have been initialized. In step 11, the diagnostic reference step position STPMM
It is determined whether K = 0. Since STPMMK = 0 at the beginning, the process proceeds to step 20, and history data CHKDGN =
0000, and in step 21, read the current step position STPM (for example, any of 1-128),
This is stored as the diagnostic reference step position STPMMMK = STPM, and this routine ends.

Information on the step position STPM is shown in FIG.
As shown in, the data is transferred from the main CPU 10 to the sub CPU 20. When the diagnosis reference step position STPMMK ≠ 0, the process proceeds from step 11 to step 12. In step 12, the current step position STPM (for example, one of 1-128) is read and the diagnostic reference step position STPMM is read.
Absolute value of difference from K (number of step changes) STEP = | ST
PM-STPMMK | is calculated, and the process proceeds to step 13.

In step 13, the step change number STEP
Is 4 (or 3) or more. STEP
When <4, it is not the time for diagnosis, and therefore this routine is ended as it is. When STEP ≧ 4, it is the diagnosis time, so the routine proceeds to step 14.

In step 14, the 4-bit history data CHKDGN stored in the history storage RAM is read to determine whether CHKDGN = 1111. CHK
In the case of DGN = 1111, it is normal and the routine proceeds to step 15 to reset the NG counter C _NG to 0, and further proceeds to step 16 to reset the disconnection detection flag F _NG to 0.
Then, the process proceeds to step 20, the history data CHKDGN = 0000 is set for the next diagnosis, and step 21
Then, the current step position STPM is read and stored as the diagnostic reference step position STPMMMK = STPM, and this routine is ended.

If CHKDGN ≠ 1111, it is abnormal and the routine proceeds to step 17, the NG counter C _NG is counted up, and the routine proceeds to step 18, where whether the value of the NG counter C _NG is a predetermined value (for example, 20) or more. Determine whether or not. If the NG counter C _NG <20, the process proceeds to step 20, the history data CHKDGN = 0000 is set for the next diagnosis, and in step 21, the current step position STPM is read and used as the diagnostic reference step position. STPMMMK = ST
It is stored as PM and this routine is finished.

If the NG counter C _NG ≧ 20, it is regarded as a wire break, the process proceeds to step 19, and the wire break detection flag F _NG is set to 1. Then, the process proceeds to step 20, the history data CHKDGN = 0000 is set for the next diagnosis, and
At step 21, the current step position STPM is read and used as the diagnostic reference step position STPMMMK = STP.
It is stored as M and this routine is finished.

By setting the disconnection detection flag F _NG = 1
The disconnection is diagnosed, the disconnection state is notified by the corresponding output, and necessary measures are taken. Here, step 12 ~
The part of step 19 corresponds to the diagnostic means, and the part of step 20 corresponds to the clearing means. According to the present invention, since the diagnosis is performed every time the step changes by more than a predetermined step, if the step position does not change, the diagnosis cannot be performed. Therefore, the following problems can be considered.

For example, in the case of a step motor of an idle speed control valve, after the wire breakage, the state of the exciting coil is fixed, so the air amount becomes insufficient or excessive, and the engine speed falls below the target speed or When it exceeds the limit, the control is performed to change the step position in order to correct it to the target rotation speed, but the step position immediately after the wire break is near the control step position (however, the frequency is low).
May not be changed by 4 steps, and in this case, immediate diagnosis cannot be performed.

However, in such a case, the frequency is low, and even if the change in every four steps cannot be obtained continuously,
Since there are many opportunities to change the step position by the amount of dashpot during open loop control, even in such a case, diagnosis is possible after a while.

[0037]

As described above, according to the present invention, the history, particularly a specific level, is detected based on only the check signal from the check circuit without detecting the energization state (drive signal state) of each exciting coil. It is possible to reliably diagnose whether or not the exciting coil is disconnected from the history of the fact that

Further, by diagnosing disconnection when the state where no disconnection can be diagnosed continues for a predetermined number of times or more, erroneous diagnosis can be prevented and the diagnostic accuracy can be further improved. Also, when storing the history of check signals,
The storage capacity can be reduced by storing only the presence or absence of the history that the check signal has reached the specific level and clearing the stored content immediately after diagnosis.

Further, the step position information is transferred from the main CPU to the sub CPU, and the diagnosis means on the sub CPU side detects the diagnosis time based on the step position information, so that the diagnosis time can be correctly detected. it can.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of the present invention.

FIG. 2 is a diagram showing a step motor drive circuit according to an embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between a drive signal and a check signal and a CPU.

FIG. 4 is a timing chart of drive signals

FIG. 5 is a timing chart of drive signals and check signals.

FIG. 6 is a timing chart showing a sampling cycle.

FIG. 7 is a flowchart of a sampling routine.

FIG. 8 is a flowchart of a diagnostic routine.

FIG. 9 is an explanatory diagram of sampling data

[Figure 10] Explanatory diagram of historical data

[Explanation of symbols]

1 step motor 2 rotor 3 and 4 the stator 10 main CPU 20 sub CPU #. 1 to # 4 exciting transistor D # 1 to D # 4 driving signal CK ₁ ~CK ₄ check circuit of the coil Tr ₁ to Tr ₄ for driving (signal line ) C # 1 to C # 4 check signals

Claims (6)

[Claims] 1. A step motor comprising a plurality of exciting coils, wherein the energizing states of these exciting coils are changed at a constant energizing cycle in accordance with a predetermined pattern, and one step rotation is obtained each time the energizing state is changed. , A device for diagnosing the presence or absence of disconnection of the exciting coil, and for each exciting coil, a check signal that is at a specific level only when the coil is energized or de-energized and there is no disconnection While the circuit is provided, sampling means for sampling the check signal from each check circuit at a cycle different from an integral multiple of the energization cycle that changes by one step, and the history of the check signal from each check circuit sampled by this sampling means are displayed. If there is no disconnection in the history storage means that stores each excitation coil and all of the excitation coils Diagnostic means for diagnosing the presence or absence of disconnection based on the stored contents of the history storage means during a change in the number of check signals from all the check circuits at least once each time to reach the specific level. A disconnection diagnostic device for a stepping motor excitation coil, characterized by being provided with. 2. A step motor comprising a plurality of exciting coils, wherein the energizing states of these exciting coils are changed at a constant energizing cycle in accordance with a predetermined pattern, and one step rotation is obtained each time the energizing state is changed. , A device for diagnosing the presence or absence of disconnection of the exciting coil, and for each exciting coil, a check signal that is at a specific level only when the coil is energized or de-energized and there is no disconnection While providing the circuit, sampling means for sampling the check signal from each check circuit at a cycle shorter than the energization cycle that changes by one step, and the history of the check signal from each check circuit sampled by this sampling means are provided for each exciting coil. The history storage means to be stored in the Whenever the check signal from the check circuit changes by a predetermined number of steps such that the check signal reaches the specific level one or more times, a diagnostic means for diagnosing the presence or absence of disconnection based on the stored contents of the history storage means during that period, A step motor excitation coil disconnection diagnosis device characterized by being provided. 3. The diagnosing means diagnoses that there is no disconnection when the history that the check signals from all the check circuits have reached the specific level is stored in the history storing means. The disconnection diagnosis device for the stepping motor exciting coil according to claim 1 or 2. 4. The disconnection diagnosis of the stepping motor exciting coil according to claim 3, wherein the diagnosing means diagnoses disconnection when a state in which no diagnosis can be made without disconnection continues for a predetermined number of times or more. apparatus. 5. The history storage means stores, for each excitation coil, whether or not there is a history that the check signal from each check circuit sampled by the sampling means has reached the specific level. The disconnection diagnosing device for the stepping motor exciting coil according to claim 1, further comprising a clearing means for clearing the stored contents immediately after the diagnosis by the diagnosing means. 6. The sampling means, history storage means, and diagnosis means are provided in a sub CPU other than the main CPU that controls the energization state of a plurality of exciting coils, and the main CP.
The step position information is transferred from the U to the sub CPU, and the diagnosis means on the sub CPU side detects the diagnosis time every time the predetermined number of steps is changed based on the step position information. The disconnection diagnostic device for the step motor exciting coil according to any one of claims 1 to 5.