Electronic control device

Abstract

To provide an electronic control device that can reduce costs by reduction in the number of sensors, and achieve reduction in a mounting area.SOLUTION: An electronic control device 10 is configured to: detect, with an edge detection / count module 2, edges of first and second PWM signals PWM_A and PWM_B to be output from a motor position sensor 1, and perform an up / down of a counter; store this counted count value in a counter information storage unit 4a upon turning off a power source; set the counted count value to a start-up initial counter information setting unit 5 upon turning on the power source; detect, in a change-over switch rotation direction angle detection unit 3, a rotation direction and a rotation angle of a change-over switch on the basis of the counter value subject to the up / down, the set counter value and an angle constant; and calculate, in a change-over switch state calculation unit 6, a state of the change-over switch on the basis of the rotation angle and the rotation direction of the change-over switch.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electronic control device that detects the rotation direction and angle of a 4WD changeover switch based on first and second PWM signals output from a motor position sensor. [Background technology]

[0002] Conventionally, an electronic control unit (ECU) that controls a transfer of a four-wheel drive vehicle detects the operation of a transfer switch (4WD changeover switch) by a driver and switches the transfer in response to the operation (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-160686 A Summary of the Invention [Problem to be solved by the invention]

[0004] In this type of ECU, for example, a rotary position sensor and a motor position sensor are mounted as a motor angle sensor to detect the driving mode instructed by the 4WD changeover switch. The rotary position sensor detects the absolute angle of the motor, and the motor position sensor detects the rotation direction. Then, the rotation angle and rotation direction of the 4WD changeover switch are calculated to determine the 2WD mode, neutral mode, AUTO mode, 4H mode, 4Lo mode, etc.

[0005] However, two motor angle sensors are required to detect the absolute angle and direction of rotation, respectively, which poses the issue of increased costs and increased mounting area due to the increased number of sensors.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electronic control device which can reduce costs and mounting area by reducing the number of sensors. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided an electronic control device comprising: a motor position sensor for detecting a rotational position of a motor; edge detection / counting means for detecting edges of first and second PWM (Pulse Width Modulation) signals output from the motor position sensor and counting up / down a counter; memory means for storing the counter value counted by the edge detection / counting means when the power is off; startup initial counter information setting means for setting the counter value stored in the memory means when the power is on; changeover switch rotation direction angle detection means for detecting the rotation direction and angle of a changeover switch based on the counter value output from the edge detection / counting means, the counter value set in the startup initial counter information setting means, and an angle constant; and changeover switch state calculation means for calculating the state of the changeover switch based on the rotation direction and angle of the changeover switch detected by the changeover switch rotation direction angle detection means. Effect of the Invention

[0008] According to the present invention, the absolute angle detected by the rotary position sensor is calculated from the relative angle of change from the initial state at startup of the electronic control device and the counter value, and the rotation direction and angle of the change-over switch are detected by the motor position sensor, so that the rotary position sensor is no longer necessary and the reduction in the number of sensors allows for reduced costs and mounting area. [Brief description of the drawings]

[0009] [Figure 1] 1 is a block diagram showing a schematic configuration of an electronic control device according to an embodiment of the present invention; [Diagram 2] FIG. 4 is a schematic diagram for explaining a 4WD changeover switch. [Diagram 3]2 is a flowchart for explaining the operation of the electronic control device shown in FIG. [Figure 4] 5 is a timing chart for explaining the relationship between the first and second PWM signals output from the motor position sensor and the counter value of the counter. [Diagram 5] 4 is a diagram for explaining the relationship between the first and second PWM signals output from the motor position sensor and the counter value of a counter. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a block diagram showing a schematic configuration of an electronic control device according to an embodiment of the present invention, and Fig. 2 is a schematic diagram for explaining a 4WD changeover switch as an example of a changeover switch.

[0011] 2, the 4WD changeover switch 11 is in 2WD mode at the start-up initial state, and when rotated clockwise, it switches between AUTO mode and 4H mode. On the other hand, when rotated counterclockwise from the start-up initial state, it switches to neutral (N) and 4Lo mode. A rotor of a motor 11a is connected to the rotating shaft of the 4WD changeover switch 11, and rotates in both forward and reverse directions according to the operation of the 4WD changeover switch 11. The driving mode designated by the 4WD changeover switch 11 is detected by detecting the rotational position of the motor 11a.

[0012] 1, a motor position sensor 1 that detects the rotational position of a motor 11a is installed in a 4WD changeover switch 11. First and second PWM (Pulse Width Modulation) signals PWM_A and PWM_B output from the motor position sensor 1 are input to an edge detection / counting module 2 provided in an electronic control device 10. The edge detection / counting module 2 detects edges of the PWM signals PWM_A and PWM_B, and increments / decrements a counter each time an edge is detected.

[0013] The counter value by the edge detection / count module 2 is input to the changeover switch rotation direction angle detection unit 3. Furthermore, this counter value is stored in the counter information storage unit (memory backup area) 4a of the memory 4 when the power is off. On the other hand, when the power is on, the counter value stored in the counter information storage unit 4a of the memory 4 is read out to the startup initial counter information setting unit 5.

[0014] The changeover switch rotation direction angle detection unit 3 receives the counter value output from the edge detection / count module 2, the counter value set in the startup initial counter information setting unit 5, and an angle constant, and calculates the state of the 4WD changeover switch 11 (the rotation angle and rotation direction of the motor 11a) based on this information. Specifically, the changeover switch rotation direction angle detection unit 3 calculates the absolute angle of the motor 11a based on the current counter value from the counter value and starting point angle of the motor position sensor 1 at startup. Then, the changeover switch state calculation unit 6 calculates the driving mode based on the detected state of the 4WD changeover switch 11.

[0015] Fig. 3 is a flowchart showing the operation of the electronic control unit 10 shown in Fig. 1. First, it is determined whether or not the power is turned on for the first time in the electronic control unit 10 (or the ignition of the vehicle) (step S1), and if it is determined to be the first operation, a counter information initial value is set (step S2). Specifically, the last input counter value from the previous operation, which was stored in the counter information storage unit 4a of the memory 4 at the time of the first power-on operation, is set as the initial value of the counter value. After the counter information initial value is set, or if it is not the first power-on operation, counter information is input from the edge detection / counting module 2 (step S3).

[0016] Next, the changeover switch rotation direction angle detection unit 3 calculates the rotation direction of the 4WD changeover switch 11. The rotation direction is calculated by analyzing the difference between the previous counter information and the current counter information, and if it is an up-count, it is a right rotation (clockwise), if it is a down-count, it is a left rotation (counterclockwise), and if there is no change, it is kept as it is (step S4).

[0017] That is, when the first and second PWM signals PWM_A, PWM_B output from the motor position sensor 1 and the counter value have the relationship shown in Figures 4 and 5, the previous and current counter values ​​are compared, and if the counter value is an up-count, it is determined to be a right rotation. The previous and current counter values ​​are also compared, and if the counter value is a down-count, it is determined to be a left rotation. Furthermore, the previous and current counter values ​​are compared, and if there is no change, the rotation direction determined previously is maintained.

[0018] 4 and 5, as shown at time t1, when the signal PWM_A is at a low level and the signal PWM_B is at a falling edge, the edge detection / counting module 2 performs a down count. As shown at time t2, when the signal PWM_A is at a rising edge and the signal PWM_B is at a low level, the edge detection / counting module 2 performs a down count. As shown at time t3, when the signal PWM_A is at a high level and the signal PWM_B is at a rising edge, the edge detection / counting module 2 performs a down count. As shown at time t4, when the signal PWM_A is at a falling edge and the signal PWM_B is at a high level, the edge detection / counting module 2 performs a down count.

[0019] On the other hand, as shown at time t5, when the signal PWM_A is at a rising edge and the signal PWM_B is at a high level, the edge detection / counting module 2 performs an up-count. As shown at time t6, when the signal PWM_A is at a high level and the signal PWM_B is at a falling edge, the edge detection / counting module 2 performs an up-count. As shown at time t7, when the signal PWM_A is at a falling edge and the signal PWM_B is at a low level, the edge detection / counting module 2 performs an up-count. As shown at time t8, when the signal PWM_A is at a low level and the signal PWM_B is at a rising edge, the edge detection / counting module 2 performs an up-count. Furthermore, as shown at time t9, when the simultaneous input of the signals PWM_A and PWM_B is maintained, the operation of the edge detection / counting module 2 is maintained.

[0020] Next, the changeover switch rotation direction angle detection unit 3 calculates the angle of the 4WD changeover switch 11 (step S5). The angle is calculated by multiplying the counter value by an angle constant. Here, the angle constant is the angle per one count of the counter. The angle per one count is defined as a constant, and the angle is calculated from the counter value. The angle per one count is calibrated in the 4WD changeover switch 11 actually mounted on the vehicle. That is, calibration is performed at the time of implementation, and the starting angle of the motor position sensor 1 is detected and stored in the counter information storage unit 4a. This angle constant may be defined for each counter value.

[0021] In the next step S6, it is determined whether the power to the electronic control device 10 (or the vehicle ignition) is off. If it is determined that the power is off, the last input counter value is stored as the final angle information of the 4WD changeover switch 11 (step S7) and is used as the initial value the next time the power is turned on.

[0022] As described above, when the 4WD changeover switch 11 is operated from the initial state at startup (2WD mode) to AUTO mode and 4H mode, the counter value is counted up in sequence, and when it is operated from the initial state at startup (2WD mode) to neutral (N) and 4Lo mode, the counter value is counted down in sequence. The counter value represents the relative angle of change from the initial state at startup of the electronic control device 10, and if the angle at startup and the angle of one count of the counter value are obtained, the current absolute angle can be calculated. Furthermore, the rotation direction of the motor 11a can be calculated from the previous counter value and the current counter value.

[0023] This makes it possible to detect the operation of the 4WD changeover switch 11 by the driver and to implement transfer control to switch the driving mode. It should be noted that the changeover switch rotation direction angle detection unit 3 determines that a wire breakage fault has occurred if no pulse edge (of the PWM signals PWM_A and PWM_B) occurs when the motor 11a is driven.

[0024] Therefore, with this configuration, the absolute angle detected by the rotary position sensor can be calculated from the relative angle of change from the initial state at startup of the electronic control unit 10 and the counter value, making it possible to detect the rotation direction and angle of the 4WD selector switch 11 using only the motor position sensor 1. As a result, a rotary position sensor is no longer necessary, and the reduction in the number of sensors allows for cost reduction and a reduction in the mounting area.

[0025] The configurations, methods, etc. described in the above-mentioned embodiments are merely schematic illustrations to enable the present invention to be understood and practiced. Therefore, the present invention is not limited to the described embodiments, and may be modified in various forms without departing from the scope of the technical ideas set forth in the claims.

[0026] For example, although a 4WD selector switch has been described, the present invention can of course be applied to other selector switches and rotary switches in general. Furthermore, when the electronic control device 10 is installed in the vehicle, if the starting angle is detected in advance and stored in the memory 4, and the counter value of the motor position sensor 1 is stored in the counter information storage unit 4a at the time of shutoff, individual differences in the electronic control device 10 can be absorbed. [Explanation of symbols]

[0027] 1...motor position sensor, 2...edge detection / count module (edge ​​detection / count means), 3...changeover switch rotation direction angle detection section (changeover switch rotation direction angle detection means), 4...memory, 4a...counter information storage section (storage means), 5...start-up initial counter information setting section (start-up initial counter information setting means), 6...changeover switch state calculation section (changeover switch state calculation means), 10...electronic control unit (ECU), 11...4WD changeover switch, 11a...motor

Claims

1. a motor position sensor that detects a rotational position of the motor; an edge detection / counting means for detecting edges of first and second PWM (Pulse Width Modulation) signals output from the motor position sensor and counting up / down a counter; a storage means for storing the counter value counted by the edge detection / counting means when the power is turned off; a start-up initial counter information setting means for setting the counter value stored in the storage means when the power is turned on; a switch rotation direction angle detection means for detecting a rotation direction and an angle of a switch based on a counter value output from the edge detection / counting means, a counter value set in a startup initial counter information setting means, and an angle constant; and a changeover switch state calculation means for calculating a state of the changeover switch based on the angle and rotation direction of the changeover switch detected by the changeover switch rotation direction angle detection means.

2. 2. The electronic control device according to claim 1, wherein an origin angle of said motor position sensor is detected, calibration is performed when mounted, and the result is stored in said storage means.

3. 2. The electronic control device according to claim 1, wherein the changeover switch rotation direction angle detection means calculates the absolute angle of the motor based on a current counter value from the counter value of the motor position sensor at the time of startup and a starting angle.

4. 2. The electronic control device according to claim 1, wherein the changeover switch rotation direction angle detection means calculates a current absolute angle based on the detected angle of the motor position sensor at the time of startup and the angle of one count of the counter value set in the startup initial counter information setting means.

5. 2. The electronic control device according to claim 1, wherein the changeover switch rotation direction angle detection means determines that a wire break has occurred when a pulse edge is not generated while the motor is being driven.

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