JP7042157B2 - Vehicle actuator control device - Google Patents

Description

The present invention relates to a control device for a vehicle actuator that drives a load such as a solenoid or a motor by a pulse drive circuit.

Patent Document 1 describes the current flowing through the resistant load, whether the voltage at the output end of the pulse drive circuit is at a high potential level or a low potential level, or the voltage at the output end when the pulse drive circuit is turned on and off. Disclosed by a load drive device that detects the occurrence of disconnection abnormality, heaven fault abnormality, and ground fault abnormality that occurred in the connection path connecting the pulse drive circuit and the resistance load based on the level of Has been done. It is described that an IPD (Intelligent Power Device) is used in the pulse drive circuit.

Japanese Unexamined Patent Publication No. 2015-55160

By the way, when an IPD having an overcurrent protection function is used in the pulse drive circuit, protection operations such as input / output cutoff are automatically performed when an overcurrent is detected, which may make general short-circuit diagnosis difficult. .. That is, when the current is cut off by the overcurrent protection operation, the pulse drive circuit does not detect the high current, so that the protection operation is canceled and the short-circuit current flows again to perform the protection operation. By repeatedly operating and releasing the overcurrent protection function in this way, the current value is controlled so as not to exceed a predetermined value, so that there is a possibility that a short circuit cannot be detected.

The present invention has been made in view of the above circumstances, and an object thereof is that the overcurrent protection function is activated when a load is driven by using a pulse drive circuit having an overcurrent protection function. Is also to provide a control device for a vehicle actuator that can detect a short circuit.

The control device for a vehicle actuator according to one aspect of the present invention has an overcurrent protection function, a pulse driving means for repeatedly applying a pulse voltage to a load, a current detecting means for detecting a current flowing through the load, and the above. The number of times that the current flowing through the load falls below the disconnection determination threshold when the load is driven by the pulse driving means with a duty of 100% for a predetermined time and the terminal voltage detecting means for detecting the voltage at the output end of the pulse driving means. The number of times the current flowing through the load exceeds the short-circuit determination threshold, and the number of times the voltage at the output end falls below the short-circuit determination threshold when the current flowing through the load is higher than the predetermined current value and lower than the short-circuit determination threshold. Based on this , it is characterized by an abnormality detecting means for detecting the occurrence of a short circuit in the current path between the pulse driving means and the load.

According to the present invention, when the load is driven by the pulse driving means with a duty of 100% for a predetermined time, at least the number of times the voltage at the output end falls below the predetermined voltage value and the number of times the current exceeds the predetermined current value. Since the occurrence of a short circuit in the current path from the pulse driving means to the load is detected based on either one, the short circuit can be detected even if the overcurrent protection function is activated and a high current does not flow.

It is a block diagram which shows the control device of the actuator for a vehicle which concerns on embodiment of this invention. It is a flowchart which shows the diagnostic process in the control device of the vehicle actuator shown in FIG. It is a flowchart which shows the diagnostic process following FIG. It is a waveform diagram for demonstrating the disconnection diagnosis. It is a waveform diagram for demonstrating the short circuit diagnosis when there is no overcurrent protection function. It is a waveform diagram which shows the current value at the time of a short circuit when there is an overcurrent protection function. It is a waveform diagram which shows the AD conversion value of the current at the time of a short circuit when there is an overcurrent protection function. It is a waveform diagram which shows the terminal voltage value at the time of a short circuit when there is an overcurrent protection function.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a control device for a vehicle actuator according to an embodiment of the present invention. Here, an example is shown in which the control unit (control device) 11 drives a load (inductive load) 12 such as a solenoid or a motor used for an actuator for a vehicle. The control unit 11 is housed in a housing (not shown), and the housing is provided with an ignition (IGN) signal terminal 13a, a power supply terminal 13b, 13c, and an output terminal 14a, 14b.

An ignition (IGN) signal is input to the IGN signal terminal 13a from the positive electrode of the battery 15 via the ignition switch 16 and the fuse 17a, respectively. Further, power is supplied to the power supply terminal 13b from the positive electrode of the battery 15 via the fuse 17b, and power is supplied to the power supply terminal 13c from the positive electrode of the battery 15 via the fuse 17c. Further, a solenoid as a load 12 is connected to the output terminals 14a and 14b.

The control unit 11 includes a microcomputer 21, an ignition (IGN) monitor circuit 22, a solenoid battery controller 23, a solenoid battery monitor circuit 24, an IPD solenoid driver 25, a voltage monitor circuit 26, a current monitor circuit 27, a fail-safe shutdown circuit 28, and a resistor. It is equipped with a vessel 29 and the like.
In response to the operation of the ignition switch 16, the IGN signal input from the IGN signal terminal 13a is input to the microcomputer 21. The IGN monitor circuit 22 monitors this IGN signal, and the monitor result is input to the microcomputer 21. The battery voltage VB applied to the power supply terminal 13b is stepped down to the internal power supply voltage by a power supply IC or the like (not shown) and supplied to the microcomputer 21. Further, the solenoid driving battery voltage VSB applied to the power supply terminal 13c is supplied to the solenoid battery controller 23.

The solenoid battery controller 23 supplies the battery voltage VSB for driving the solenoid applied to the power supply terminal 13c to the IPD solenoid driver 25 under the control of the microcomputer 21. This battery voltage VSB is monitored by the solenoid battery monitor circuit 24, and the monitor result is input to the microcomputer 21.
The IPD solenoid driver 25 works as a pulse drive circuit (pulse drive means) that repeatedly applies a pulse voltage to the load 12. The IPD solenoid driver 25 generates a PWM (Pulse Width Modulation) signal under the control of the microcomputer 21, outputs the PWM (Pulse Width Modulation) signal to the load 12 from the output terminals 14a and 14b, and drives the IPD solenoid driver 25. The fail-safe shutdown circuit 28 acts as an overcurrent protection device that protects the IPD solenoid driver 25 from overcurrent under the control of the microcomputer 21, and outputs from the IPD solenoid driver 25 when an overcurrent flows through the load 12. The pulse voltage to be generated is cut off.

The current monitor circuit 27 functions as a current detecting means for detecting the current flowing through the load 12, detects the voltage level generated at both ends of the resistor 29, and uses this voltage level between the output terminals 14a and 14b in the microcomputer 21. Calculate the current value flowing through. Further, the voltage monitor circuit 26 functions as a terminal voltage detecting means for detecting the voltage at the output end of the IPD solenoid driver 25, and inputs the detected voltage level to the microcomputer 21.

The microcomputer 21 includes an AD (Analog-to-Digital) converter, and has a battery voltage VSB monitored by the solenoid battery monitor circuit 24, a current value flowing through the load 12 monitored by the current monitor circuit 27, and a voltage monitor. The terminal voltage between the output terminals 14a and 14b detected by the circuit 26 is converted into a digital signal and acquired. The microcomputer 21 functions as an abnormality detection device (abnormality detection means), and the number of times the voltage at the output end falls below a predetermined voltage value when the load 12 is driven by the IPD solenoid driver 25 with a duty of 100% for a predetermined time. , And, based on at least one of the number of times the current exceeds a predetermined current value, a short circuit in the current path between the IPD solenoid driver 25 and the load 12, such as a sky fault or ground fault at the output terminals 14a or 14b. It is designed to detect the occurrence of an abnormality. Further, the disconnection of the current path between the IPD solenoid driver 25 and the load 12 can be diagnosed based on the monitor current detected by the current monitor circuit 27.

It is necessary that the load 12 to be driven can be driven with a duty of 100%, and that the behavior is not affected even if the load 12 is driven with a duty of 100%. For example, in a vehicle system in which the pressing force of the clutch is changed by driving the load 12, when the load 12 is driven with a duty of 100%, the clutch is pressed with the maximum force, but if it is an initial process before the start of control, There is no problem because the vehicle is not operating. Further, in a system that moves a certain mechanism to a predetermined position, since it is driven with a duty of 100% immediately after starting, it is preferable that the system automatically returns to the initial position by a spring or the like.

2 and 3 are flowcharts showing diagnostic processing in the control device for the vehicle actuator shown in FIG. 1, respectively. This diagnostic process is executed when the vehicle is started, for example, in the initial process immediately after the system is started. Alternatively, it can be carried out even when the vehicle is stopped. Further, in the normal operation mode, the load 12 may be driven by the PWM signal having a duty of 100% and then executed.

When the diagnosis is started, first, the microcomputer 21 issues an instruction to output a PWM signal having a duty of 100% to the IPD solenoid driver 25 (step S1). Next, it is determined whether or not a predetermined time (fixed period) has elapsed (step S2). If it has not elapsed, the current value monitored by the current monitor circuit 27 is AD-converted and acquired by the microcomputer 21 (step S3), and then the terminal voltage (output terminals 14a, 14b) monitored by the voltage monitor circuit 26 is obtained. The voltage between them) is AD-converted and acquired by the microcomputer 21 (step S4), and the process returns to step S2. Then, the operations of steps S2 to S4 are repeated until a predetermined time elapses.
Here, since the driveable time of 100% duty and the sampling cycle of the AD conversion value are different for each system, the drive time and sampling cycle are set according to the system.

When it is determined in step S2 that the predetermined time has elapsed, the microcomputer 21 issues an instruction to stop the PWM signal to the IPD solenoid driver 25 (step S5). Next, it is determined whether or not the loop is performed by the number of AD conversion values acquired by the microcomputer 21 (determination operation is performed) (step S6), and if not looped, it is determined whether or not the AD conversion value is valid. (Step S7). This step S7 is for selecting an effective AD conversion value according to the dead zone and the like at the time of PWM drive for each load 12. As a result, when a PWM signal is given to the load 12, an error component generated by a delay in the rise of current or voltage due to a resistance component, a capacitance component, an induction component, or the like of the load 12 is removed.

If it is determined in step S7 that the AD conversion value is valid, it is determined whether or not the AD conversion value of the current is smaller than the disconnection determination threshold value (step S8), and if it is determined to be small, the disconnection determination counter is counted up. (Step S9) and return to step S6. If it is determined in step S8 that the AD conversion value of the current is not smaller than the disconnection determination threshold value, the process proceeds to step S10 to determine whether or not the AD conversion value of the current is larger than the short circuit determination threshold value. If it is determined in step S10 that the AD conversion value of the current is larger than the short-circuit determination threshold value, the short-circuit determination counter is counted up (step S11) and the process returns to step S6. If it is determined in step S10 that the AD conversion value of the current is not larger than the short circuit determination threshold value, the process proceeds to step S12 and it is determined whether or not the terminal voltage AD conversion value is smaller than the short circuit determination threshold value. If it is determined in step S12 that the terminal voltage AD conversion value is smaller than the short-circuit determination threshold value, the short-circuit determination counter is counted up (step S13) and the process returns to step S6. If it is determined that the terminal voltage AD conversion value is not smaller than the disconnection determination threshold value, the process returns to step S6 without doing anything.

On the other hand, if it is determined in step S7 that the AD conversion value is not valid, the process returns to step S6, and this AD conversion value is not used for diagnosis.
Further, in step S6, when it is determined that the loop is performed by the number of AD conversion values acquired by the microcomputer 21, it is determined whether or not the count value of the disconnection determination counter is larger than the specified number (step S14). If it is determined to be large, it is determined that the wire is broken and the process ends (step S15). If it is determined that the count value of the disconnection determination counter is not larger than the specified number, the disconnection determination counter is cleared (step S16), and it is determined whether or not the count value of the short circuit determination counter is larger than the specified number (step S16). Step S17). If it is determined to be large, it is determined to be a short circuit and the process ends (step S18). If it is determined that the count value of the short-circuit determination counter is not larger than the specified number, the short-circuit determination counter is cleared (step S19), and the process is determined to be normal and ends (step S20).
In step S14 and step S17, since the failure determination criteria of each counter are different for each system, it is preferable to set the number of times the failure is confirmed for each system.

As described above, when the current value flowing through the load 12 exceeds the threshold value for determining a short circuit, the short circuit determination counter is counted up (step S10), and when a predetermined count value is reached, it is determined to be a short circuit. (Steps S17 and S18). Further, when the current value falls below the threshold value for determining the disconnection, the disconnection determination counter is counted up (step S9), and when the predetermined count value is reached, the disconnection is determined (steps S14 and S15).
If the current value does not determine a short circuit (steps S8, S10), the short circuit determination counter is counted up when the terminal voltage falls below the threshold value determined to be a short circuit (steps S12, S13). When the count value is reached, it is determined that a short circuit has occurred (steps S17 and S18).

When it is determined that the disconnection abnormality or the short circuit abnormality is performed, the pulse voltage output from the IPD solenoid driver 25 is cut off, and the drive of the load 12 is prohibited by the fail-safe shutdown circuit 28. In the driving cycle in which the abnormality is determined, the driving of the load 12 is prohibited, and basically the normal return is not performed. Then, the failure diagnosis is performed again in the initial processing of the next driving cycle, and if it is normal, the failure diagnosis is performed again.
However, in consideration of misdiagnosis, when returning to the driving cycle determined to be abnormal, for example, in the case of a vehicle, this failure diagnosis is performed again while the vehicle is stopped (on the system, when it can be driven with 100% duty). If it is determined to be normal, it will be restored.

Next, the diagnostic operation of disconnection, heavenly fault, and ground fault will be described in detail with reference to the waveform diagrams of FIGS. 4 to 8. The disconnection is diagnosed by referring to the AD conversion value of the current when the duty of the PWM signal is 100% indicated. As shown in FIG. 4, when a disconnection occurs at time t0, the AD conversion value of the current becomes near zero after time t0, so that it is detected and determined to be disconnection.
The short circuit diagnosis (without the overcurrent protection function) is performed by referring to the AD conversion value of the current when the duty of the PWM signal is 100% indicated. As shown in FIG. 5, when a short circuit occurs at time t1, the AD conversion value of the current maintains a high current after time t1, so that it is determined to be a short circuit by detecting it.

If there is an overcurrent protection function, the AD conversion value of the current does not become a high current even if the duty of the PWM signal is instructed to be 100% when a short circuit occurs. This is because, as shown in FIG. 6, when a high current is generated due to a short circuit (time t1), the overcurrent protection is activated and the current path is cut off (time t2), and when the high current stops flowing, the current path is opened. As a result, a high current flows again (time t3). By repeating this, as shown in FIG. 7, the AD conversion value of the current is averaged, and the high current value is not obtained.
Therefore, in the pulse drive circuit (PWM drive circuit) using the IPD having the overcurrent protection function, the short circuit diagnosis cannot be detected only by the AD conversion value of the current.

Therefore, the terminal voltage of the load 12 is used for the short circuit diagnosis instead of the current value flowing through the load 12. The terminal voltage of the load 12 is always equal to the applied voltage in the indicated state where the duty of the PWM signal is 100% when there is no failure. When a short circuit occurs in a pulse drive circuit with an overcurrent protection function, the AD conversion value of the terminal voltage is also averaged by high-speed switching in the same way as the AD conversion value of the current, and the applied voltage at normal times. It will be a lower value. Therefore, as shown in FIG. 8, the voltage drop ΔV from the normal voltage is detected to determine the short circuit of the pulse drive circuit having the overcurrent protection function.

In the above-described embodiment, the case where the load 12 is an inductive load such as a solenoid or a motor has been described as an example, but diagnosis can be performed regardless of the type of load.
If multiple loads are attached to one system, this diagnosis is applied to each load, and if a load among the multiple loads is determined to be a failure, the diagnosis is applied. Depending on the importance of the function to which the load belongs, it may be judged whether or not the failure diagnosis of other loads is performed. For example, if it is important, the system will be stopped due to the failure of the load, so no further load diagnosis is necessary. If not important, continue diagnosis for other loads.

Further, when the pulse drive circuit is driven with a duty of 100% for a predetermined time, the pulse drive circuit is based on the number of times the voltage at the output end falls below the predetermined voltage value or the number of times the current exceeds the predetermined current value. Although the occurrence of a short circuit is detected, both the voltage value and the current value may be considered. It can also be configured to detect the occurrence of a short circuit in the pulse drive circuit based on the number of times the voltage at the output end falls below a predetermined voltage value and the number of times the current exceeds a predetermined current value.

11 ... Control unit (control device), 12 ... Load (inductive load), 13b, 13c ... Power supply terminal, 14a, 14b ... Output terminal, 15 ... Battery, 21 ... Microcomputer (abnormality detection means), 25 ... IPD solenoid Driver (pulse drive means), 26 ... Voltage monitor circuit (terminal voltage detection means), 27 ... Current monitor circuit (current detection means), 28 ... Fail-safe shutdown circuit (overcurrent protection device)

Claims (3)

A pulse drive means that has an overcurrent protection function and repeatedly applies a pulse voltage to the load,
A current detecting means for detecting the current flowing through the load, and
A terminal voltage detecting means for detecting the voltage at the output end of the pulse driving means, and
When the load is driven by the pulse driving means with a duty of 100% for a predetermined time , the number of times the current flowing through the load falls below the disconnection determination threshold, the number of times the current flowing through the load exceeds the short-circuit determination threshold, and the load. When the current flowing through the current is higher than a predetermined current value and lower than the short-circuit determination threshold, the current path between the pulse drive means and the load is based on the number of times the voltage at the output end falls below the short-circuit determination threshold . A control device for a vehicle actuator including an abnormality detecting means for detecting the occurrence of a short circuit. The control device according to claim 1, wherein the overcurrent protection function cuts off a pulse voltage output from the pulse driving means when an overcurrent flows through the load. Actuator control device. The control device for a vehicle actuator according to claim 1 or 2, wherein the pulse driving means drives the load at 100% duty when the vehicle is started or stopped.

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