JP2001164974A - Failure sensing device for actuator driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly sense ground short-circuitting failure of connection terminals of an actuator in respect to a bidirectional driving circuit which drives a movable member retained in a stable position in normal and reverse directions. SOLUTION: A motor driving device has a motor 6 for opening and closing a throttle valve, a bridge circuit 45 for rotating the motor 6 in normal and reverse directions by carrying current through PWM driving, and an opener mechanism for retaining the throttle valve at an opening position of the opener when the current carrying to the motor 6 is stopped. Failure in relation to the motor 6 is sensed by determination of a microcomputer 41. The microcomputer 41 determines occurrence of failure that connection terminals 6a, 6b of the motor 6 in respect to the bridge circuit 45 are short-circuitted to the ground GND, through the normal or reverse rotation of the motor 6 and the position of the throttle valve on the opening or closing side compared to the opener opening position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device for an actuator such as a motor, which can drive in both forward and reverse directions by energizing. More specifically, the present invention relates to a failure detection device that detects a failure in this type of actuator drive device.

[0002]

2. Description of the Related Art Conventionally, as an actuator driving device,
There is a type in which a bridge circuit formed by connecting four transistors in a bridge is provided, and a motor as an actuator connected to the bridge circuit is PWM-driven. In this type of motor driving device, when a short circuit fault occurs in a transistor of a bridge circuit, the current flowing through the circuit or the motor becomes excessive, and it becomes difficult to drive the motor normally. Therefore, in order to cope with this kind of short-circuit failure, it is necessary to appropriately detect the failure.

Here, Japanese Patent Application Laid-Open No. 9-285182 discloses an example of this type of failure detection device. FIG. 10 shows an outline of the configuration. The motor drive device to be detected by the failure detection device includes the first to fourth motors constituting the bridge circuit 81.
Transistors 82, 83, 84 and 85. One end of the bridge circuit 81 is connected to the power supply 87 via the relay 86, and the other end of the circuit 81 is connected to the ground GND via the shunt resistor 88. The motor 89 is connected to the bridge circuit 81 by a pair of terminals 89a and 89b.
In addition, the driving device includes a plurality of driving circuits 90A and 90A for selectively driving each of the transistors 82 to 85 by PWM.
90B, 90C, 90D, a current detection circuit 91 connected to a shunt resistor 88, a relay 86 and each drive circuit 9
And a control circuit 92 for controlling 0A to 90D. The control circuit 92 includes a first and a second transistor 82 connected to the power supply side among the transistors 82 to 85,
83 and one of the third and fourth transistors 84 and 85 connected to the ground side is turned off, and the other of the power supply side transistors 82 and 83 and the other of the ground side transistors 84 and 85 are PWM-driven or By turning on the motor 89, the motor 89 is rotated forward or backward. Here, the failure detection device includes a shunt resistor 88, a current detection circuit 91, and a control circuit 92. The shunt resistor 88 and the current detection circuit 91 are for detecting a current flowing through the bridge circuit 81. The control circuit 92 compares the current value detected by the shunt resistor 88 and the current detection circuit 91 with a predetermined reference value to determine whether the current value is abnormal. That is, the control circuit 92 previously stores, as function data, an abnormality determination area that is predetermined in relation to the PWM signal (duty value) to each of the transistors 82 to 85 and the current detected by the shunt resistor 88 or the like.
When the control circuit 92 determines that the relationship between the actual duty value and the actual detected current value falls within the abnormality determination region, that is, when the detected current value is abnormally increased, ８５85 are detected to have a short-circuit failure.

As a device to which the above-mentioned motor drive device is applied, for example, there is an electronic throttle control device applied to an automobile engine or the like. The electronic throttle control device includes an electronic throttle, an opener mechanism for the throttle valve, and a controller for controlling the electronic throttle.

The electronic throttle drives a linkless type throttle valve to be opened and closed by a motor. The controller calculates and sets the target opening of the throttle valve based on the operation amount of the accelerator pedal by the driver, and calculates an opening deviation between the set target opening and the actually detected throttle valve actual opening. The opening / closing operation of the throttle valve is controlled by calculating the feedback and selectively performing feedback control of the motor in both forward and reverse directions based on the opening deviation. The above-described motor drive device is applied for drive control of this motor.

The opener mechanism prevents the throttle valve from being rotated in the closing direction by the return spring when the power supply to the motor is stopped. The throttle valve is slightly opened from the fully closed state by balancing with the opener spring. This is for maintaining the open state (opener opening degree). By holding the throttle valve at the opener degree in this way, it is possible to deal with, for example, a failure of the electronic throttle while the vehicle is running. That is, if a failure occurs in the electronic throttle while the vehicle is running, the control of the electronic throttle is forcibly stopped by stopping the energization of the motor in order to prevent the electronic throttle from operating carelessly. By keeping the throttle valve at the opener opening during such troubleshooting, even after the electronic throttle control is forcibly stopped,
The opening of the opener secures the minimum required intake air to keep the engine running, allowing the vehicle to evacuate to the roadside. In an electronic throttle having such an opener mechanism, the opener opening of the throttle valve held when the motor is not energized means a stable position for the throttle valve determined by the balance between the return spring and the opener spring. Become. Then, the throttle valve is driven in the opening direction or the closing direction by the motor with the opening of the opener as a boundary.

[0007]

However, in the conventional failure detecting device, the terminals 89a and 89b of the motor 89 are not provided.
When a failure occurs such that the short circuit occurs to the ground GND, the current flowing through the transistors 82 and 83 on the power supply side flows to the ground GND without passing through the shunt resistor 88. Therefore, this type of short-circuit failure cannot be detected by detecting an excessive current using the shunt resistor 88 or the like.

Here, the inventor of the present application uses an electronic throttle control device to which the above-described motor drive device is applied, and in a state where the throttle valve is driven by a predetermined amount from the opener opening to the opening direction and held, the motor connection terminal is grounded. In the event of a short-circuit failure, we discovered that there was some kind of relationship. That is, the inventor of the present invention has proposed a method of connecting the motor when the relationship between the opening / closing position with respect to the opening degree of the throttle valve and the direction of the motor drive output shows a state completely opposite to the normal state (abnormal state). We discovered that a failure in which the terminal was short-circuited to ground occurred, and confirmed the detectability of the failure.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to move a movable member such as a throttle valve, which is held at a stable position such as an opener degree by a holding means such as an opener mechanism, in both forward and reverse directions. Actuator that enables the drive output in both forward and reverse directions by energization in order to operate in the opposite direction, and that can properly detect a failure in which the connection terminal of the actuator to the bidirectional drive circuit is short-circuited to ground. An object of the present invention is to provide a failure detection device for a drive device.

[0010]

In order to achieve the above object, according to the first aspect of the present invention, a drive output in both forward and reverse directions is provided by energizing a predetermined movable member in both forward and reverse directions. And a bidirectional drive circuit that allows the actuator to be driven in both forward and reverse directions to drive and output the actuator in both forward and reverse directions. A failure detecting device for detecting a failure in the actuator driving device having a holding means for holding the movable member at a predetermined stable position, wherein at least the direction of the drive output of the actuator and the operating position of the movable member with respect to the stable position are determined. When the relationship has continued for a predetermined period of time in an abnormal state for a predetermined time or more, failure determination means for determining that a failure has occurred in the bidirectional drive circuit is provided. To.

In a conventional failure detection device, a current flowing through a bridge circuit is detected by a shunt resistor or the like. If the detected current value is abnormally increased, it is determined that a short-circuit failure has occurred in a transistor constituting the bridge circuit. Was to be detected. For this reason, if a failure occurs such that the connection terminal of the actuator is short-circuited to the ground, no current flows through the shunt resistor, etc., and this type of short-circuit failure can be detected under the same conditions as in the past. Did not. However, according to the configuration of the present invention, when the relationship between at least the direction of the drive output of the actuator and the operating position of the movable member with respect to the stable position continues in an abnormal state for a predetermined time or more, a failure occurs in the bidirectional drive circuit. The occurrence is determined by the failure determination means. Therefore, the short-circuit failure can be detected regardless of the presence or absence of a shunt resistor or the like. Here, the abnormal state of the relationship between the direction of the drive output of the actuator and the operating position of the movable member with respect to the stable position means, for example, that the direction of the drive output of the actuator is positive, while This means that the operating position is at a position opposite to the stable position.

In order to achieve the above object, the invention according to claim 2 enables a drive output in both forward and reverse directions by energizing the throttle valve provided in the intake passage to open and close in both directions. A motor, a throttle sensor for detecting the opening of the throttle valve, and a plurality of transistors are connected in a bridge, and the motor is driven in both forward and reverse directions to drive and output the motor in both forward and reverse directions. A failure in the motor drive device including a bridge circuit that enables the power supply to the motor and an opener mechanism for holding the throttle valve at a predetermined opener opening slightly opened from the fully closed state when the power supply to the motor is stopped. In the failure detection device for detecting, at least the relationship between the direction of the motor drive output and the opening / closing position of the throttle valve with respect to the opener opening is not correct. When it continues for a predetermined time or longer at normal conditions, and purpose that a failure in the bridge circuit with a computer determines that occurred.

According to the configuration of the present invention, it is determined by the computer that a failure has occurred in the bridge circuit based on the relationship between the drive output direction of the motor and the open / close position of the throttle valve regardless of the presence or absence of a shunt resistor or the like. Is determined,
The failure can be detected.

According to a third aspect of the present invention, there is provided an actuator for driving a predetermined movable member in both forward and reverse directions by energizing the actuator. A bidirectional drive circuit that allows the actuator to be driven in both the forward and reverse directions so as to drive and output the actuator in the forward and reverse directions; In a failure detection device that detects a failure in an actuator drive device including a holding unit for holding the actuator at a stable position and a current detection unit for detecting a current flowing through the actuator or the bidirectional drive circuit, the amount of current supplied to the actuator is When the detected current value is smaller than a predetermined reference value when the current value is larger than a predetermined value in the forward direction or the reverse direction, When it continued constant time or more, and the spirit that a failure in the bidirectional drive circuit is provided for determining failure determining means to have occurred.

According to the configuration of the present invention, since the current flowing through the actuator or the bidirectional drive circuit is detected by the current detecting means, when a part of the configuration of the bidirectional drive circuit is short-circuited, When the detected current value abnormally increases, occurrence of the short-circuit fault is determined.
However, if a short-circuit fault occurs at the connection terminal of the actuator with respect to the bidirectional drive circuit, no current flows to the current detecting means, so that the occurrence of the short-circuit fault cannot be determined under the same conditions as the above conditions. However, according to the configuration of the present invention, when the amount of current to the actuator is larger than a predetermined value in the forward direction or the reverse direction, when the detected current value is smaller than the predetermined reference value and continues for a predetermined time or more. The failure determination means determines that a failure has occurred in the bidirectional drive circuit, and the failure can be detected.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] Hereinafter, a first embodiment in which a failure detection device for an actuator drive device according to the present invention (claims 1 and 2) is embodied in an electronic throttle control device will be described. This will be described in detail with reference to the drawings.

FIG. 1 shows a schematic configuration of the electronic slot control device. The electronic throttle control device includes an electronic throttle 2 having an opener mechanism 1 and a throttle controller 3 for controlling the electronic throttle 2. The electronic throttle 2 is for adjusting the output of an automobile engine (not shown). The electronic throttle 2 opens and closes a throttle valve 5 provided in an intake passage 4 of the engine by a motor 6. The actual opening (actual opening) TA is detected by the throttle sensor 7. The throttle valve 5 is a linkless type that does not mechanically interlock with the operation of the accelerator pedal 8. That is, the throttle valve 5 operates by receiving the driving force of the motor 6 controlled by the throttle controller 3 based on the operation amount of the accelerator pedal 8 detected by the accelerator sensor 9. In this embodiment, the opener mechanism 1 corresponds to the holding means of the present invention, the throttle valve 5 corresponds to the movable member of the present invention, and the motor 6 corresponds to the actuator of the present invention.

The throttle valve 5 is rotatably supported by a throttle shaft 10 passing through the intake passage 4. A motor 6 is connected to one end of the throttle shaft 10, and a throttle sensor 7 is connected to the other end. The output shaft of the motor 6 is directly connected to the throttle shaft 10 without using a gear.

The throttle sensor 7 is composed of, for example, a potentiometer. The accelerator sensor 9 detects the amount of operation of the accelerator pedal 8 by the driver as the target opening RA in order to set the target opening RA of the throttle valve 5, and is constituted by, for example, a potentiometer.

The opener mechanism 1 is for maintaining the throttle valve 5 at the opener opening TO slightly opened from the fully closed state when the power supply to the motor 6 is stopped. FIG. 2 shows a configuration concept of an electronic throttle 2 including the opener mechanism 1, and FIG. 3 shows an operation of a throttle valve 5 by the opener mechanism 1. As shown in FIG. 1, an electronic throttle 2 and an opener mechanism 1 are a throttle housing (hereinafter, simply referred to as “housing”) 3.
1 are provided integrally. The throttle valve 5 is disposed in the intake passage 4 and is supported by the housing 31 so as to be rotatable about the throttle shaft 10. A motor 6 is connected to one end of the throttle shaft 10, and a throttle sensor 7 is connected to the other end of the throttle shaft 10. Here, regarding the opening and closing of the throttle valve 5, as shown in FIG. 3, the direction from the fully closed position S to the fully open position F is defined as the opening direction, and the direction from the fully open position F to the fully closed position S is defined as the closing direction. .

The opener mechanism 1 provided at the other end of the throttle shaft 10 has an opener lever 32 for holding the throttle valve 5 at a predetermined opener opening position N when the engine is stopped, that is, when the motor 6 is not energized. Is provided. One end of a return spring 33 is fixed to the opener lever 32, and the other end of the spring 33 is connected to the housing 3.
Fixed to 1. The return spring 33 biases the throttle valve 5 via the opener lever 32 in the closing direction. The opener lever 32 engages with the full-open stopper 34 at a predetermined rotation position and stops. The housing 31 is provided with a fully closed stopper 35 for holding the throttle valve 5 at the fully closed position S. One end of an opener spring 36 is fixed to the opener lever 32. The other end of the opener spring 36 is fixed to the throttle shaft 10.
The opener spring 36 urges the throttle valve 5 in the opening direction. In this embodiment, the opener lever 3
2, the return spring 33, the fully open stopper 34, the fully closed stopper 35, the opener spring 36 and the like constitute the opener mechanism 1 of the present invention.

Here, the biasing force of the return spring 33 is set smaller than the driving force of the motor 6 and larger than the detent torque when the motor 6 is not energized.
This setting is such that when the motor 6 is energized, the throttle valve 5 is opened and closed against the urging force of the return spring 33 or the opener spring 36, and when the electric current is not energized, the throttle valve 5 is balanced by the return spring 33 and the opener spring 36. Predetermined opener opening position N
It is for holding in.

As shown in FIG. 3, the opener position N
Is the initial opening when the power supply to the motor 6 is stopped when the engine is stopped. On the other hand, when the power supply to the motor 6 is stopped during the operation of the engine, the operation of the engine is performed while maintaining the output level at which the opener opening position N allows the vehicle to evacuate to the road shoulder. The opening can be maintained. When the engine is stopped or when the motor 6 is not energized, the throttle shaft 1
The return spring 36 urges the 0 and the opener lever 32 in the closing direction. At the same time, the throttle shaft 10 is urged by the opener spring 36 in the opening direction. The balance between the return spring 33 and the opener spring 36 holds the throttle valve 5 at the opener position N. In this embodiment, the opener mechanism 1 corresponds to a holding means of the present invention for holding the throttle valve 5 at the opener opening position N as a predetermined stable position when the power supply to the motor 6 is stopped. .

Open the throttle valve 5 to the opener position N
To open the full open position F, the driving force of the motor 6 acts on the throttle shaft 10 against the urging force of the return spring 33, and the throttle shaft 10 rotates until the opener lever 32 engages the fully open stopper 34. Will be done. On the other hand, in order to close the throttle valve 5 from the opener opening position N to the fully closed position S, the driving force of the motor 6 acts on the throttle shaft 10 against the biasing force of the opener spring 36, and the coaxial 10 is fully closed. It is rotated until it engages with 35.

Here, during operation of the engine, the motor 6
Is feedback-controlled by the throttle controller 3 based on the operation of the accelerator pedal 8,
The throttle valve 5 is opened at a predetermined target opening. At this time, the target opening of the throttle valve 5 is determined in the operation range from the fully closed position S to the fully opened position F as shown in FIG. At the fully opened position F, the opener lever 32 is engaged with the fully opened stopper 34, so that the throttle valve 5 is held in a state where the intake passage 4 is fully opened. This fully open stopper 3
Since the throttle valve 4 is provided, the throttle valve 5 does not rotate excessively in the opening direction beyond the fully open position F. On the other hand, in the fully closed position S, since the throttle shaft 10 is engaged with the fully closed stopper 35, the throttle valve 5 is held in a state where the intake passage 4 is fully closed. Since the fully closed stopper 35 is provided, the throttle valve 5 does not rotate excessively in the closing direction beyond the fully closed position S. And the motor 6
Is stopped, the return valve 33 and the opener spring 36 are balanced as described above, so that the throttle valve 5 is held at the opener opening position N slightly opened from the fully closed state S.

FIG. 4 is a block diagram showing an electric configuration of the throttle controller 3 and the like. The throttle controller includes a microcomputer (microcomputer) 41, an A / D converter 42, a differential amplifier 43, a drive circuit 44, and a bridge circuit 45. In this embodiment, a motor drive device for driving the motor 6 includes a microcomputer 41, a drive circuit 44, a bridge circuit 45, a power supply 50, and the like. The bridge circuit 45 is configured by bridge-connecting first to fourth field-effect transistors (first to fourth FETs) 46, 47, 48, and 49. Bridge circuit 45
Is connected to a power supply 50, and the other end of the circuit 45 is connected to a ground GND via a shunt resistor 51. The drive circuit 44 is for driving the FETs 46 to 49 of the bridge circuit 45. The motor 6 is connected to the bridge circuit 45 by a pair of connection terminals 6a and 6b. One of the connection terminals 6a is connected to the first FET 46 and the third F
ET48, and the other connection terminal 6b is connected to the second
And the fourth FET 49.
The shunt resistor 51 is connected to the A / D converter 42 via the differential amplifier 43. A / D converter 42 and drive circuit 4
4 is connected to the microcomputer 41. As is well known, the microcomputer 41 includes a central processing unit (CPU), a read / write memory (RAM), a read-only memory (ROM), and the like. The ROM stores a control program for the electronic throttle 2, a failure detection program for detecting a failure of the motor drive device, and the like. The A / D converter 42 converts an analog signal output from each of the sensors 7 and 9 into a digital signal and outputs the digital signal to the microcomputer 41. The drive circuit 44 receives a control signal output from the microcomputer 41 and outputs a drive signal to the motor 6 via the bridge circuit 45. In this embodiment, the microcomputer 41 includes the electronic throttle 2
And the failure detection of the motor drive device, and constitutes failure determination means of the present invention.

An analog signal corresponding to the actual opening TA output from the throttle sensor 7 is converted into a digital actual opening signal by an A / D converter 42, and the signal is input to the microcomputer 41. An analog signal corresponding to the target opening RA output from the accelerator sensor 9 is also A /
The signal is converted into a digital value target opening signal by the D converter 42, and the signal is input to the microcomputer 41.

The microcomputer 41 controls the motor 6 based on the actual opening signal and the target opening signal input according to the PID control method. That is, the microcomputer 41 calculates the value of the opening deviation ERR between the target opening RA and the actual opening TA based on the input signal values, and calculates a predetermined formula based on the value of the opening deviation ERR. , The value of the control amount duty is calculated. Then, the microcomputer 41 outputs a control signal (duty signal) corresponding to the value of the control amount duty to the motor 6 as a drive signal via the drive circuit 44 and the bridge circuit 45, and controls the coil current of the motor 6. As a result, the microcomputer 41 performs feedback control of the motor 6 to bring the actual opening TA of the throttle valve 5 closer to the target opening RA.

Here, the drive circuit 44 selectively switches each of the FETs 46 to 49 of the bridge circuit 45 based on the control amount duty calculated by the microcomputer 41, so that the coil current of the motor 6 is controlled. Is changed by using a PWM method. That is, the microcomputer 4
1 turns on the first FET 46 by the drive circuit 44,
The third FET 48 is turned off. At this time, the microcomputer 4
1 is to drive the fourth FET 49 by PWM based on the value of the predetermined control amount duty by the drive circuit 44,
The second FET 47 is PWM-driven with a phase opposite to that of the fourth FET 49. Thereby, the first FET 46, the connection terminal 6a, the motor 6, the connection terminal 6b, and the fourth FET
The motor current MI is controlled in the positive direction so as to flow in the order of 49. Then, when the return current FI flows through the second FET 47, the microcomputer 41 turns on the second FET 47 while turning off the fourth FET 49. Thereby, the power consumption of the second FET 47 is reduced to the first and fourth powers.
Power consumption of the FETs 46 and 49 of the second F
The amount of heat generated by the ET 47 is reduced. Conversely, microcomputer 4
1 turns off the fourth FET 49 and turns on the second FET 47 by the drive circuit 44. At this time, the microcomputer 41 causes the drive circuit 44 to PWM-drive the third FET 48 based on the value of the predetermined control amount duty, and also causes the first FET 46 to be PWM-driven in the opposite phase to the third FET 48. Thereby, the microcomputer 41 sets the second FET 47, the connection terminal 6b, the motor 6, the connection terminal 6
The motor current MI is controlled in the reverse direction so as to flow through the third FET 48a and the third FET 48 in order. When the return current FI flows through the first FET 46, the microcomputer 41 sets the third FE
While T48 is turned off, the first FET 46 is turned on. As a result, the power consumption of the first FET 46 approaches the power consumption of the second and third FETs 47 and 48, and the amount of heat generated by the first FET 46 is suppressed.

Here, an example of the PWM drive of the bridge circuit 45 is shown in the time charts of FIGS. FIG. 5 shows each FET 4 when the control amount duty is set to “75%” and the motor 6 is driven in the forward direction (that is, when the motor 6 is rotated forward).
6 shows switching states of Nos. 6 to 49. FIG. 6 shows each FET 46 in the case where the control amount duty is set to “−75%” and the motor 6 is driven in the reverse direction (ie, in the case of “reverse rotation”).
49 shows the switching states of No. to No. 49. When the motor drive device is operating normally, in order to hold the throttle valve 5 on the opening side of the opener opening position N against the urging force of the opener mechanism 1, the control amount duty is set to a positive value. A positive motor current MI flows through the bridge circuit 45. Conversely, in order to hold the throttle valve 5 closer to the closing side than the opener opening position N against the urging force of the opener mechanism 1, the control circuit duty is set to a negative value and the motor current in the reverse direction MI will flow.

Next, the contents of the failure detection program for the motor drive device executed by the microcomputer 41 will be described. FIG. 7 is a flowchart showing the processing contents of this failure detection program. The microcomputer 41 periodically executes this routine at predetermined time intervals.

When the processing of this routine starts, in step 100, the microcomputer 41 sets the control amount du set this time.
It is determined whether the value of ty is greater than “0”. The value of the control amount duty is calculated and set by a separate “electronic throttle control routine”. Control amount du
When the value of ty is larger than “0”, the microcomputer 41
The process moves to step 110.

At step 110, the microcomputer 41 determines whether or not the value of the actual opening TA detected by the throttle sensor 7 is smaller than the opener opening TO which is a stable position. If the value of the actual opening TA is smaller than the value of the opener opening TO, the microcomputer 41 increments the value of the counter CUT by “1” in step 111 and shifts the processing to step 120. If the value of the actual opening TA is not smaller than the value of the opener opening TO, the microcomputer 41
Clears the value of the counter CUT to "0" in step 112 and shifts the processing to step 120.

At step 120, the microcomputer 41 determines whether or not the value of the counter CUT is larger than a predetermined reference value CUT1. That is, it is determined whether or not a predetermined time corresponding to the reference value CUT1 has elapsed since the actual opening degree TA became a value closer to the closing side than the opener opening degree TO even though the control amount duty was a positive value. You do it. Here, when the conditions of steps 100 and 110 are satisfied, or when the conditions of steps 130 and 140 are satisfied, the reference value C
Waiting for the elapse of the predetermined time corresponding to UT1 is because when the throttle valve 5 moves even in a normal state, the motor 6 is driven in the reverse direction to stop the movement of the valve 5 near the target opening. This is to avoid erroneous detection of a failure due to this.
If the determination result is affirmative, it is determined that a failure has occurred in the motor drive device, and the microcomputer 41 sets the failure detection flag XF to “1” in step 121 and temporarily ends the subsequent processing. . That is, here, the connection terminal 6 of the motor 6 to the bridge circuit 45 of the motor drive circuit is used.
It is determined that a failure has occurred in which a and 6b are short-circuited to the ground GND, and the failure detection flag XF is set to “1”. If the result of the determination in step 120 is negative, the microcomputer 41 determines that the motor driving device is normal and the microcomputer 41 once ends the subsequent processing.

On the other hand, in step 100, the control amount duty
Is not greater than "0", step 130
Then, the microcomputer 41 determines whether or not the value of the control amount duty set this time is smaller than “0”. Control amount du
When the value of ty is smaller than “0”, the microcomputer 41
The process proceeds to a step 140.

In step 140, the microcomputer 41 determines whether or not the value of the actual opening TA detected by the throttle sensor 7 is larger than the opener opening TO which is a stable position. If the value of the actual opening TA is larger than the value of the opener opening TO, the microcomputer 41 increments the value of the counter CUT by “1” in step 141 and proceeds to step 120.

In step 130, if the value of the control amount duty is not smaller than "0", or step 140
If the value of the actual opening TA is not larger than the value of the opener opening TO, the microcomputer 41 clears the counter CUT to “0” in step 142 and shifts the processing to step 120.

Then, step 141 or step 14
2 and steps 120 and 121, the microcomputer 4
1 performs the same processing as described above.

As described above, according to the configuration of the failure detection device of the present embodiment, the direction of the drive output of the motor 6
Based on the relationship with the open / close position of the throttle valve 5, the microcomputer 45 determines that a failure has occurred in which the connection terminals 6a and 6b of the motor 6 in the motor drive circuit are short-circuited to the ground GND. That is, the relationship between whether the operation of the motor 6 is in the forward rotation state or the reverse rotation state and whether the throttle valve 5 is located on the opening side or the closing side of the opener opening TO is determined. The microcomputer 4 detects that the connection terminals 6a and 6b of the motor 6 with respect to the bridge circuit 45 are short-circuited to the ground GND.
5 is determined.

For example, it is assumed that one connection terminal 6b of the motor 6 with respect to the bridge circuit 45 is short-circuited to the ground GND while the throttle valve 5 is held at a position on the opening side of the opener opening TO. At this time, the control amount duty
Is positive, but the fourth FET 49 to be PWM driven is
Is short-circuited, the value of the control amount duty becomes the same as "100%", and the throttle valve 5 attempts to move to the open side. However, since the microcomputer 41 performs feedback control of the motor 6 based on the detection value of the throttle sensor 7, the value of the control amount duty eventually decreases and becomes a negative value. Then, the negative control amount dut
When it becomes y, the power supply 50, the second FET 4
7, connection terminal 6b, motor 6, connection terminal 6a, third F
Since a slight current flows in the order of ET48 and ground GND, the microcomputer 41 tries to reverse the motor 6 to move the throttle valve 5 to the closing side of the opener opening TO (opener opening position N). become. However, during the off period, since the current flows in the order of the power supply 50, the first FET 46, the connection terminal 6a, the motor 6, the connection terminal 6b, and the ground GND, the microcomputer 41 sets the throttle valve 5 to the opener TO (opener open). In order to move the motor 6 to the open side from the degree position N), the motor 6 is to be normally rotated. Then, the opening drive and the closing drive of the throttle valve 5 are well balanced with the control amount duty having a negative value, and the throttle valve 5 stops at the target opening.
Therefore, the control amount duty has a negative value even though the throttle valve 5 is stopped on the opening side of the opener opening TO. That is, an abnormal state is shown in which the relationship between the direction of the drive output of the motor 6 and the open / close position of the throttle valve 5 with respect to the opener opening TO is completely opposite to the case where the relationship is normal. Here, the inventor of the present application has previously determined that the case where the relationship of the abnormal state is established is when the connection terminals 6a and 6b of the motor 6 with respect to the bridge circuit 45 are short-circuited to the ground GND and have a failure. Confirmed experimentally.

Here, in the conventional failure detection device, the current flowing through the bridge circuit 81 is detected by a shunt resistor 88 or the like, and when the detected current value is abnormally increased, Transistors 82 to
Assuming that a short-circuit failure has occurred in 85, this is detected. Therefore, when a failure occurs such that the connection terminals 89a and 89b of the motor 89 are short-circuited to the ground GND, the current does not flow through the shunt resistor 88, and the current value becomes excessive according to the conventional condition. Failed to detect this type of short circuit fault. However, according to the failure detection device of the present embodiment, the relationship between the direction of the drive output of the motor 6 and the open / close position of the throttle valve 5 with respect to the opener opening TO (opener opening position N) is in the abnormal state. It is determined that a failure has occurred in which the connection terminals 6a and 6b of the motor 6 with respect to the bridge circuit 45 are short-circuited to the ground GND. For this reason, regardless of the presence or absence of a shunt resistor or the like used in the conventional failure detection device, the opener TO
Connection of the motor 6 to the bridge circuit 45 with respect to the motor 6 for which the drive output in the forward and reverse bidirectional directions is enabled by energization in order to operate the throttle valve 5 held at the (opener opening position N) in the open and close directions. A failure in which the terminals 6a and 6b are short-circuited to the ground GND can be properly detected.

Since the failure detecting device of this embodiment includes the shunt resistor 51 similarly to the conventional example, the shunt resistor 51 and the differential amplifier 43 provided corresponding thereto are used, and the shunt resistor 51 is used. The short-circuit fault in each of the FETs 46 to 49 can be detected by the microcomputer 41 determining the magnitude of the current flowing through the FETs 46 to 49 in the same manner as in the conventional fault detection device.

[Second Embodiment] Next, a second embodiment of the present invention (claim 3) will be described with reference to the drawings. still,
In the present embodiment, the same members and the like as those in the configuration of the failure detection device in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Hereinafter, different points will be mainly described.

This embodiment is different from the first embodiment in the processing contents of the failure detection program executed by the microcomputer 41. In this embodiment, the shunt resistor 51 and the differential amplifier 43 shown in FIG. Further, the microcomputer 41 corresponds to the short-circuit failure detecting means of the present invention.

FIG. 8 shows the processing contents of the failure detection program executed by the microcomputer 41. That is, in this embodiment, steps 200 and 210 and steps 230 and 24
Steps 100 and 11 shown in FIG.
0 and the processing contents of steps 130 and 140.

That is, when the processing of the routine shown in FIG. 8 starts, in step 200, the microcomputer 41 determines that the value of the control amount duty set this time is "a positive predetermined value (for example, 70
%) ”Is determined. When the value of the control amount duty is larger than the “positive predetermined value”, the microcomputer 41
The process moves to step 210.

At step 210, the microcomputer 41 determines whether or not the value of the motor current MI detected by the shunt resistor 51 and the differential amplifier 43 is smaller than a predetermined reference value MI1. Here, the reference value MI1 means, for example, a current value corresponding to a predetermined control amount duty. If the value of the motor current MI is smaller than the reference value MI1, the microcomputer 41 determines in step 211 that the counter CU
The value of T is incremented by “1”, and the process proceeds to step 220. The value of the motor current MI is equal to the reference value MI1.
If not smaller, the microcomputer 41 proceeds to step 21
In step 2, the value of the counter CUT is cleared to "0", and the process proceeds to step 220.

On the other hand, in step 200, the control amount duty
Is not larger than the "positive predetermined value",
0, the microcomputer 41 sets the control amount duty set this time.
Is smaller than “negative predetermined value (for example, −70%)”. If the value of the control amount duty is smaller than the “negative predetermined value”, the microcomputer 41 proceeds to step 240
Move to.

At step 240, the microcomputer 41 determines whether or not the value of the motor current MI detected by the shunt resistor 51 or the like is smaller than the reference value MI1. And
When the value of the motor current MI is smaller than the reference value MI1,
The microcomputer 41 increments the value of the counter CUT by “1” in step 241 and proceeds to step 220.
Move to.

In step 230, when the value of the control amount duty is not smaller than the "negative predetermined value", or in step 2
If the value of the motor current MI is not smaller than the reference value MI1 at 40, the microcomputer 41 clears the counter CUT to “0” at step 242 and shifts the processing to step 220.

Then, after shifting from step 211 or 212 or step 241, 242, at step 220, the microcomputer 41 determines that the value of the counter CUT is equal to the predetermined reference value CU.
It is determined whether it is larger than T1. That is, the control amount du
Although the value of ty is larger than the “positive predetermined value” or smaller than the “negative predetermined value”, a predetermined time corresponding to the reference value CUT1 has elapsed since the motor current MI became smaller than the reference value MI1. It is determined whether or not. If the determination result is affirmative, it is determined that a short-circuit failure has occurred in the motor drive device, and the microcomputer 41 sets the failure detection flag XF to “1” in step 221 and temporarily ends the subsequent processing. I do. That is, here, the terminals 6a and 6b of the motor 6 with respect to the bridge circuit 45 are connected to the ground G.
The failure detection flag XF is set to "1" assuming that a failure shorting to ND has occurred. Step 2
If the determination result in 20 is negative, the motor drive device is assumed to be normal, and the microcomputer 41 temporarily ends the subsequent processing.

As described above, according to the configuration of the failure detection device of the present embodiment, the detection by the shunt resistor 51 and the differential amplifier 43 is performed even though the absolute value of the control amount duty is larger than the "predetermined value". When the value of the motor current MI is smaller than the predetermined reference value MI1 and continues for a predetermined time or more, a failure occurs in which the connection terminals 6a and 6b of the motor 6 to the motor driving device are short-circuited to the ground GND. Is determined by the microcomputer 41. That is, the motor 6 is rotated forward or backward at a positive predetermined drive amount or more or a negative predetermined drive amount or less, and the necessary and sufficient motor current MI does not flow through the bridge circuit 45 at that time. The microcomputer 45 determines that a failure has occurred in which the connection terminals 6a and 6b of the motor 6 to the bridge circuit 45 are short-circuited to the ground GND. In this sense, in order to operate the throttle valve 5 held at the opener opening TO (opener opening position N) by the opener mechanism 1 in the opening and closing directions, a motor that enables drive output in the forward and reverse directions by energizing. Per 6
Connection terminal 6 for the bridge circuit 45 of the motor 6
It is possible to properly detect a failure in which the a and 6b are short-circuited to the ground GND.

For example, with the throttle valve 5 held on the open side from the opener opening TO (opener opening position N), one connection terminal 6a of the motor 6 is connected to the ground GND.
Is short-circuited. In this case, although the control amount duty is a positive value, the power supply 50, the first FET 46, the connection terminal 6
Most of the motor current MI flowing in the order of a, the motor 6, the connection terminal 6b, the fourth FET 49, and the ground GND flows through the path of the power supply 50, the first FET 46, the connection terminal 6a, and the ground GND. As a result, the force of the motor 6 for moving the throttle valve 5 to the open side is weakened. However, since the microcomputer 41 performs feedback control of the motor 6 based on the detection value of the throttle sensor 7, the control amount d
The value of uty gradually increases and becomes larger than the “positive predetermined value”. Here, during the period in which the first FET 46 is turned off, the motor current MI flows in the reverse order of the power supply 50, the second FET, the connection terminal 6b, the motor 6, the connection terminal 6a, and the ground GND, so that the throttle valve 5 Is moved to the closing side from the opener opening TO (opener opening position N), which is also a cause of an increase in the control amount duty. Therefore, although the control amount duty is greater than the “positive predetermined value”, most of the motor current MI
It flows on the path of the first FET 46, the connection terminal 6a, and the ground GND, and it becomes difficult to flow through the shunt resistor 51. Therefore, when the motor current MI is smaller than the reference value MI1 even though the control amount duty is larger than the “positive predetermined value”, the connection terminals 6a and 6b of the motor 6 are connected to the ground G.
It is determined that a failure that short-circuits to the ND has occurred.

It should be noted that the present invention is not limited to the above-described embodiments, and can be carried out as follows without departing from the spirit of the invention.

In each of the above embodiments, the present invention is embodied in an electronic throttle control device, in which the throttle valve 5 is provided as a movable member, the motor 6 is provided as an actuator, and the opener mechanism 1 is provided as holding means. On the other hand, as shown in FIG. 9, there is provided a movable member 63 that is horizontally reciprocated by the actuator 62 between the pair of regulating walls 61A and 61B. The movable members 63 are
A pair of springs 64 biasing from different directions by 80 °
A and 64B are provided to constitute holding means together with the regulating walls 61A and 61B. Then, the horizontal position of the movable member 63 may be detected by the position sensor 65. In this case, the movable member 63 is held by the holding means with the position where the urging forces of both springs 64A and 64B are balanced as the stable position.

[0056]

According to the first aspect of the present invention,
Failure in which the connection terminal to the bidirectional drive circuit of the actuator, which has enabled the drive output in both the forward and reverse directions by energizing the movable member held in the stable position by the holding means in the forward and reverse directions, is short-circuited to ground. Can be detected properly.

According to the configuration of the second aspect of the present invention, in order to operate the throttle valve held at the opener opening position by the opener mechanism in the opening and closing directions, the drive output can be performed in the forward and reverse directions by energizing. Thus, it is possible to properly detect a failure in which the connection terminal for the bridge circuit of the motor is short-circuited to the ground.

According to the configuration of the third aspect of the present invention, the movable member held at the stable position by the holding means is operated in the forward and reverse directions so that the drive output can be performed in the forward and reverse directions by energizing. Thus, it is possible to properly detect a failure in which the connection terminal of the actuator to the bidirectional drive circuit is short-circuited to the ground.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an electronic throttle control device according to a first embodiment.

FIG. 2 is a conceptual diagram showing the configuration of an electronic throttle including an opener mechanism.

FIG. 3 is an explanatory view of an operation of a throttle valve by an opener mechanism.

FIG. 4 is an electric circuit diagram showing a failure detection device and the like.

FIG. 5 is a time chart showing an example of PWM driving for each FET.

FIG. 6 is a time chart showing an example of PWM driving for each FET.

FIG. 7 is a flowchart showing the processing contents of a failure detection program.

FIG. 8 is a flowchart showing processing contents of a failure detection program according to the second embodiment.

FIG. 9 is a conceptual configuration diagram showing a failure detection device and the like according to another embodiment.

FIG. 10 is an electric circuit diagram showing a failure detection device and the like according to a conventional example.

[Explanation of symbols]

 Reference Signs List 1 opener mechanism (holding means) 5 throttle valve (movable member) 6 motor (actuator) 41 microcomputer (failure determination means) 45 bridge circuit (bidirectional drive circuit) 46 first FET 47 second FET 48 third FET 49 Fourth FET 51 Shunt resistor (current detecting means) 52 Differential amplifier (current detecting means) 61A regulating wall (holding means) 61B regulating wall (holding means) 62 actuator 63 movable member 64A spring (holding means) 64B spring ( Holding means) TO Opener opening (stable position) N Opener opening position (stable position)

Claims (3)

[Claims] 1. An actuator which enables a predetermined movable member to be driven in both forward and reverse directions by energizing the movable member in both forward and reverse directions, and an actuator which drives and outputs the actuator in both forward and reverse directions. A bidirectional drive circuit that enables the actuator to be energized in both forward and reverse directions; and holding means for holding the movable member at a predetermined stable position when energization of the actuator is stopped. In a failure detection device that detects a failure in an actuator drive device, at least a relationship between a direction of a drive output of the actuator and an operation position of the movable member with respect to the stable position,
A failure detection device for an actuator drive device, comprising: failure determination means for determining that a failure has occurred in the bidirectional drive circuit when the failure has continued for a predetermined time or more in an abnormal state. 2. A motor for driving a throttle valve provided in an intake passage in an opening / closing direction in both directions by energizing the motor to enable a drive output in a forward / reverse direction, and for detecting an opening degree of the throttle valve. A throttle sensor, a bridge circuit formed by bridge-connecting a plurality of transistors, and a bi-directional bidirectional current supply to the motor in order to drive and output the motor in the bidirectional direction; A failure detection device for detecting a failure in a motor drive device having an opener mechanism for holding the throttle valve at a predetermined opener opening slightly opened from a fully closed state when energization is stopped; When the relationship between the direction of the drive output and the open / close position of the throttle valve with respect to the opener opening is in an abnormal state at a predetermined time When continued above, the failure detection apparatus for a motor drive device characterized by failure to the bridge circuit comprising computer determines that occurred. 3. An actuator which enables a predetermined movable member to be driven in both forward and reverse directions by energizing the movable member in both forward and reverse directions, and an actuator which drives and outputs the actuator in both forward and reverse directions. A bidirectional drive circuit that enables energization in both forward and reverse directions to the actuator, holding means for holding the movable member at a predetermined stable position when energization of the actuator is stopped, and the actuator Alternatively, in the failure detection device for detecting a failure in the actuator drive device including current detection means for detecting a current flowing through the bidirectional drive circuit, the amount of current supplied to the actuator is greater than a predetermined value in a forward direction or a reverse direction. In this case, it is assumed that the detected current value has continued for a predetermined time or more while being smaller than a predetermined reference value. , Failure detection device for an actuator drive apparatus characterized by failure to the bidirectional drive circuit is provided for determining failure determining means to have occurred.