Circuit for diagnosing EPB caliper motor fault

Abstract

The utility model discloses a circuit for diagnosing faults of an EPB caliper motor. The EPB motor H-bridge driving circuit comprises two parts, an EPB motor H-bridge driving module comprises four MOS transistors, and the four MOS transistors are connected between the two ends of an EPB caliper motor M and a power source and the ground to form an H-bridge circuit; the EPB motor load diagnosis part comprises two load diagnosis modules, the two load diagnosis modules are connected to the two ends of an EPB caliper motor M respectively, the two load diagnosis modules are connected with the MCU, and each load diagnosis module comprises a composite triode. According to the utility model, faults such as EPB motor node open circuit, short circuit to a power supply, short circuit to the ground and the like can be diagnosed and identified, and the use safety of an EPB electronic parking system is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of automobile electronic circuits, in particular to a circuit for diagnosing EPB caliper motor faults. Background Art

[0002] The EPB electronic parking system controls the caliper motor of the power head to clamp or release the caliper to meet the user's parking needs. As one of the main actuators, the correct action of the caliper motor is an important part of the EPB functional safety design.

[0003] Generally, the EPB electronic parking system controller focuses on the realization of functions, but lacks the fault diagnosis of the caliper motor. The missing motor failure has the following two problems: 1. It cannot guarantee the safety of users in using the EPB electronic parking system, and there are problems such as being unable to park due to motor failure. 2- At the same time, the fault diagnosis of the missing motor cannot meet the national standard for the safety standards of passenger car electronic and electrical functions. Utility Model Content

[0004] In order to solve the problems existing in the background technology, the utility model proposes a circuit for diagnosing the fault of the EPB caliper motor, which solves the technical problem that the fault diagnosis of the EPB caliper motor cannot be performed in real time.

[0005] The technical solution of the utility model is achieved in this way:

[0006] The utility model comprises two parts, namely, an EPB motor H-bridge driving module and an EPB motor load diagnosis part; the EPB motor H-bridge driving module comprises four MOS tubes, which are connected between the two ends of the EPB caliper motor M and a power supply and a ground, forming an H-bridge circuit; the EPB motor load diagnosis part comprises two load diagnosis modules, which are respectively connected to the two ends of the EPB caliper motor M, and the two load diagnosis modules are both connected to a micro-control unit MCU.

[0007] The EPB motor H-bridge driving module includes MOS tubes Q1 to Q4;

[0008] The drain pins of the MOS tube Q3 and the MOS tube Q4 are both connected to the vehicle power supply line VBAT_MR, the gate pin of the MOS tube Q3 is connected to the drive signal port DRV_Q3 of the micro-control unit MCU, the gate pin of the MOS tube Q4 is connected to the drive signal port DRV_Q4 of the micro-control unit MCU, the source of the MOS tube Q3 is connected to the positive terminal EPB_L+ of the EPB caliper motor M, and the source of the MOS tube Q4 is connected to the negative terminal EPB_L- of the EPB caliper motor M;

[0009] The source pins of the MOS tube Q1 and the MOS tube Q2 are both connected to the ground, the gate pin of the MOS tube Q2 is connected to the drive signal port DRV_Q2 of the micro-control unit MCU, the gate pin of the MOS tube Q1 is connected to the drive signal port DRV_Q1 of the micro-control unit MCU, the drain pin of the MOS tube Q2 is connected to the positive terminal EPB_L+ of the EPB caliper motor M, and the drain pin of the MOS tube Q1 is connected to the negative terminal EPB_L- of the EPB caliper motor M.

[0010] In the EPB motor load diagnosis section,

[0011] The first load diagnosis module includes a composite transistor U1, which is composed of two transistors connected, the emitter of the first transistor of the composite transistor U1 is grounded, the base of the first transistor is connected to the drive signal port M_DRV_EPB_L+ of the micro-control unit MCU, the collector of the first transistor is connected to the base of the second transistor, the emitter of the second transistor is connected to the power supply, the collector of the second transistor is connected to the positive terminal EPB_L+ of the EPB caliper motor M through the diode D1 and the resistor R5 in sequence, the resistor R1 and the capacitor C1 are connected in parallel and then connected in series with the resistor R3 between the positive terminal EPB_L+ of the EPB caliper motor M and the ground, and an analog-to-digital conversion port M_AD_EPB_L+ connected to the micro-control unit MCU is led out between the resistor R1 and the resistor R3;

[0012] The second load diagnosis module includes a compound transistor U2, which is composed of two transistors connected. The emitter of the first transistor of the compound transistor U2 is grounded, the base of the first transistor is connected to the drive signal port M_DRV_EPB_L- of the micro-control unit MCU, the collector of the first transistor is connected to the base of the second transistor, the emitter of the second transistor is connected to the power supply, and the collector of the second transistor is connected to the positive terminal EPB_L- of the EPB caliper motor M through a diode D2 and a resistor R6 in sequence. After the resistor R2 and the capacitor C2 are connected in parallel, they are connected in series with the resistor R4 between the positive terminal EPB_L- of the EPB caliper motor M and the ground, and an analog-to-digital conversion port M_AD_EPB_L- connected to the micro-control unit MCU is led out between the resistor R2 and the resistor R4.

[0013] Beneficial effects of the utility model:

[0014] The utility model can diagnose the circuit to identify the faults such as open circuit of EPB motor node, short circuit to power supply, short circuit to ground and the like, thereby improving the use safety of the EPB electronic parking system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The schematic diagram of a circuit for diagnosing EPB caliper motor M fault. DETAILED DESCRIPTION

[0016] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0017] like Figure 1 As shown, the circuit includes two parts: a microcontroller unit MCU, an EPB motor H-bridge driver module, and an EPB motor load diagnosis part.

[0018] The EPB motor H-bridge drive module includes four MOS tubes, which are connected between the two ends of the EPB caliper motor M and the power supply and the ground to form an H-bridge circuit; the EPB caliper motor M is also connected to the power supply and the ground respectively through the H-bridge circuit.

[0019] The EPB motor load diagnosis part includes two load diagnosis modules, which are respectively connected to the two ends of the EPB caliper motor M, and both load diagnosis modules are connected to the micro-control unit MCU.

[0020] The microcontroller unit MCU outputs high and low levels to the two parts of the EPB motor H-bridge drive module and the EPB motor load diagnosis part, and then receives the signal through the analog-to-digital conversion port to quickly diagnose the fault of the EPB caliper motor M.

[0021] like Figure 1 As shown, the EPB motor H-bridge drive module includes MOS tubes Q1 to Q4;

[0022] The drain pins No. 2 of the MOS tube Q3 and the MOS tube Q4 are both connected to the vehicle power supply line VBAT_MR, the gate pin No. 1 of the MOS tube Q3 is connected to the drive signal port DRV_Q3 of the micro-control unit MCU, the gate pin No. 1 of the MOS tube Q4 is connected to the drive signal port DRV_Q4 of the micro-control unit MCU, the source electrode No. 3 of the MOS tube Q3 is connected to the positive terminal EPB_L+ of the EPB caliper motor M, and the source electrode No. 3 of the MOS tube Q4 is connected to the negative terminal EPB_L- of the EPB caliper motor M;

[0023] The No. 3 source pins of the MOS tube Q1 and the MOS tube Q2 are both connected to the ground, the No. 1 gate pin of the MOS tube Q2 is connected to the drive signal port DRV_Q2 of the micro-control unit MCU, the No. 1 gate pin of the MOS tube Q1 is connected to the drive signal port DRV_Q1 of the micro-control unit MCU, the No. 2 drain pin of the MOS tube Q2 is connected to the positive terminal EPB_L+ of the EPB caliper motor M, and the No. 2 drain pin of the MOS tube Q1 is connected to the negative terminal EPB_L- of the EPB caliper motor M.

[0024] like Figure 1 As shown in the EPB motor load diagnosis section,

[0025] The first load diagnosis module includes a compound transistor U1, which is composed of two connected transistors. The emitter No. 1 of the first transistor of the compound transistor U1 is grounded, the base No. 2 of the first transistor is connected to the drive signal port M_DRV_EPB_L+ of the micro-control unit MCU, the collector No. 6 of the first transistor is connected to the base No. 5 of the second transistor, the emitter No. 4 of the second transistor is connected to the power supply 5V, and the collector No. 3 of the second transistor is connected to the positive terminal EPB_L+ of the EPB caliper motor M through the diode D1 and the resistor R5 in sequence. The resistor R1 and the capacitor C1 are connected in parallel and then connected in series with the resistor R3 between the positive terminal EPB_L+ of the EPB caliper motor M and the ground, and the analog-to-digital conversion port M_AD_EPB_L+ connected to the micro-control unit MCU is led out between the resistor R1 and the resistor R3.

[0026] The second load diagnosis module includes a compound transistor U2, which is composed of two transistors connected. The emitter No. 1 of the first transistor of the compound transistor U2 is grounded, the base No. 2 of the first transistor is connected to the drive signal port M_DRV_EPB_L- of the micro-control unit MCU, the collector No. 6 of the first transistor is connected to the base No. 5 of the second transistor, the emitter No. 4 of the second transistor is connected to the power supply 5V, and the collector No. 3 of the second transistor is connected to the positive terminal EPB_L- of the EPB caliper motor M through the diode D2 and the resistor R6 in sequence. The resistor R2 and the capacitor C2 are connected in parallel and then connected in series with the resistor R4 between the positive terminal EPB_L- of the EPB caliper motor M and the ground, and the analog-to-digital conversion port M_AD_EPB_L- connected to the micro-control unit MCU is led out between the resistor R2 and the resistor R4.

[0027] In the specific implementation, the models of MOS tubes Q1, Q2, Q3, and Q4 are IAUC60N04S6N044, the resistance values ​​of resistors R3 and R4 are 10K, the resistance values ​​of resistors R2 and R1 are 30K, the resistance values ​​of resistors R5 and R6 are 1K, the capacitance values ​​of capacitors C1 and C2 are 100nF, the models of diodes D1 and D2 are: S-LBAS21HT1G, and the models of composite transistors U1 and U2 are: PUMD16-Q.

[0028] The drive signal ports DRV_Q1 to DRV_Q4 of the microcontroller unit MCU all output low levels, so that the EPB caliper motor M is disconnected from the vehicle power supply line VBAT_MR and the ground line;

[0029] A) When the drive signal port M_DRV_EPB_L+ and the drive signal port M_DRV_EPB_L- of the micro-control unit MCU output either a high level, the other outputs a low level, or the two are interchanged, real-time detection is performed through the analog-to-digital conversion port M1_AD_EPB_L+ and the analog-to-digital conversion port M1_AD_EPB_L- of the micro-control unit MCU:

[0030] If the voltages detected by the analog-to-digital conversion port M1_AD_EPB_L+ and the analog-to-digital conversion port M1_AD_EPB_L- are not zero and are respectively the values ​​of the following formulas, then the EPB caliper motor M has no fault:

[0031] U AD+ =(U1-U2)*R2 / (R2+R4)

[0032] U AD- =(U1-U2)*R1 / (R3+R1)

[0033] Among them, U AD+ , U AD- They respectively represent the voltages detected by the analog-to-digital conversion port M1_AD_EPB_L+ and the analog-to-digital conversion port M1_AD_EPB_L-, U1 represents the voltage value of the power supply, and U2 represents the voltage drop of the diode D1 / D2;

[0034] B) When the drive signal port M_DRV_EPB_L+ of the micro-control unit MCU outputs a low level and the drive signal port M_DRV_EPB_L- outputs a high level, if the voltages detected by the analog-to-digital conversion port M1_AD_EPB_L+ and the analog-to-digital conversion port M1_AD_EPB_L- are both zero, the EPB caliper motor M is short-circuited to the ground;

[0035] C) When the drive signal port M_DRV_EPB_L+ of the microcontroller unit MCU outputs a low level and the drive signal port M_DRV_EPB_L- outputs a high level, if the voltages detected by the analog-to-digital conversion port M1_AD_EPB_L+ and the analog-to-digital conversion port M1_AD_EPB_L- are not zero and are respectively the values ​​of the following formulas, the EPB caliper motor M is short-circuited to the vehicle power supply:

[0036] U AD+ =U3*R2 / (R2+R4)

[0037] U AD- =U3*R1 / (R3+R1)

[0038] Among them, U3 is the voltage of the vehicle power supply;

[0039] D) When the drive signal port M_DRV_EPB_L+ of the microcontroller unit MCU outputs a low level and the drive signal port M_DRV_EPB_L- outputs a high level, if the voltage detected by the analog-to-digital conversion port M1_AD_EPB_L+ is zero, and the voltage detected by the analog-to-digital conversion port M1_AD_EPB_L- is the value of the following formula, then the positive terminal EPB_L+ of the EPB caliper motor M is open:

[0040] U AD- =(U1-U2)*R2 / (R2+R4)

[0041] E) When the drive signal port M_DRV_EPB_L- of the microcontroller unit MCU outputs a low level and the drive signal port M_DRV_EPB_L+ outputs a high level, if the voltage detected by the analog-to-digital conversion port M1_AD_EPB_L- is zero, and the voltage detected by the analog-to-digital conversion port M1_AD_EPB_L+ is the value of the following formula, then the negative terminal EPB_L- of the EPB caliper motor M is open:

[0042] U AD+ =(U1-U2)*R1 / (R3+R1).

[0043] In specific implementation, the diagnosis of the EPB motor is performed under the premise that the motor M is not in operation, that is, the drive signals DRV_Q1, DRV_Q2, DRV_Q3, and DRV_Q4 corresponding to the MOS tubes Q1, Q2, Q3, and Q4 are all low. At this time, the motor M will be disconnected from the power supply line VBAT_MR of the vehicle power supply and the ground line.

[0044] The specific diagnosis modes are as follows: no-fault mode, the motor M is short-circuited to the ground at 0 V, the motor M is short-circuited to the power supply, the EPB_L+ node of the motor M is open, and the EPB_L- node of the motor M is open.

[0045] No-failure mode:

[0046] When the drive signal port M_DRV_EPB_L+ outputs a low level (0V), the composite transistor U1 is not conducting, and the voltage of the pin 4 of the composite transistor U1 cannot be loaded onto the pin 3;

[0047] And the output of the driving signal port M_DRV_EPB_L- is high level (5V), at this time the composite transistor U2 is turned on, and the voltage 5V of pin 4 of the composite transistor U2 is loaded onto pin 3.

[0048] At this time, under the driving voltage, the voltage detected by the analog-to-digital conversion port M1_AD_EPB_L- is equal to:

[0049] (U1-U2)*R2 / (R2+R4)=(5V-0.7V)*(10K / 10K+30K)=4.3V*0.25=1.075V.

[0050] Because the motor M is not moving, the wire inside is similar to a short circuit, so the voltage detected by the analog-to-digital conversion port M1_AD_EPB_L+ is equal to:

[0051] (U1-U2)*R1 / (R3+R1)=(5V-0.7V)*(10K / 10K+30K)=4.3V*0.25=1.075V.

[0052] When the drive signal port M_DRV_EPB_L+ outputs a high level (5V), the composite transistor U1 is turned on, and the voltage 5V of the pin 4 of the composite transistor U1 is loaded onto the pin 3;

[0053] And the output of the driving signal port M_DRV_EPB_L- is low level (0V), at this time the composite transistor U2 is not turned on, and the voltage of pin 4 of the composite transistor U2 cannot be loaded onto pin 3.

[0054] At this time, under the driving voltage, the voltage of the analog-to-digital conversion port M1_AD_EPB_L+ is equal to:

[0055] (U1-U2)*R1 / (R3+R1)=(5V-0.7V)*(10K / 10K+30K)=4.3V*0.25=1.075V.

[0056] Because the motor M is not moving, the wire inside is similar to a short circuit, so the voltage of the analog-to-digital conversion port M1_AD_EPB_L- is equal to:

[0057] (U1-U2)*R2 / (R2+R4)=(5V-0.7V)*(10K / 10K+30K)=4.3V*0.25=1.075V.

[0058] This indicates that the motor is not faulty.

[0059] Failure Mode 1:

[0060] The motor M is short-circuited to the ground at 0 V. At this time, the negative terminal EPB_L- and the positive terminal EPB_L+ are 0 V, so the voltage of M_AD_EPB_L- is equal to 0 V, and the voltage of M_AD_EPB_L+ is equal to 0 V. At this time, it is determined that the motor M is short-circuited to the ground.

[0061] Fault mode 2: Motor M is short-circuited to the vehicle power supply. The voltage of the vehicle power supply is 12V. At this time, the negative terminal EPB_L- and the positive terminal EPB_L+ are 12V.

[0062] The voltage of the analog-to-digital conversion port M_AD_EPB_L is equal to:

[0063] 12V*R2 / (R2+R4)=12V*(10K / 10K+30K)=12V*0.25=3V.

[0064] The voltage of the analog-to-digital conversion port M_AD_EPB_L+ is equal to:

[0065] 12V*R1 / (R3+R1)=12*(10K / 10K+30K)=12V*0.25=3V.

[0066] At this time, it is determined that the motor M is short-circuited to the power supply.

[0067] Failure Mode 3:

[0068] The node of the positive terminal EPB_L+ of the motor M is open, the M_DRV_EPB_L+ drive signal is low, and the M_DRV_EPB_L- drive signal is high; at this time, the voltage of the analog-to-digital conversion port M1_AD_EPB_L- is equal to (5V-0.7V)*R2 / (R2+R4)=(5V-0.7V)*(10K / 10K+30K)=4.3V*0.25=1.075V.

[0069] Since the EPB_L+ node of the motor M is open, the voltage of the analog-to-digital conversion port M_AD_EPB_L+ is equal to 0V.

[0070] Failure Mode 4:

[0071] The node of the negative terminal EPB_L- of the motor M is open, the M_DRV_EPB_L+ driving signal is high, and the M_DRV_EPB_L- driving signal is low. At this time, the voltage of the analog-to-digital conversion port M1_AD_EPB_L+ is equal to (5V-0.7V)*R1 / (R3+R1)=(5V-0.7V)*(10K / 10K+30K)=4.3V*0.25=1.075V. At this time, the voltage of the analog-to-digital conversion port M_AD_EPB_L- is equal to 0V.

[0072] The overall diagnostic truth table is as follows:

[0073]

[0074] It can be seen from the above table that the utility model can accurately, quickly and efficiently detect the EPB caliper motor M fault according to this logic.

[0075] The above specific implementation modes are used to explain the present invention rather than to limit the present invention. Any modification and change made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A circuit for diagnosing EPB caliper motor M fault, characterized in that: It includes two parts: an EPB motor H-bridge driving module and an EPB motor load diagnosis part; the EPB motor H-bridge driving module includes four MOS tubes, which are connected between the two ends of the motor and the power supply and the ground to form an H-bridge circuit; the EPB motor load diagnosis part includes two load diagnosis modules, which are respectively connected to the two ends of the motor, and the two load diagnosis modules are connected to the micro-control unit MCU.

2. A circuit for diagnosing a fault of an EPB caliper motor M according to claim 1, characterized in that: The motor is an EPB caliper motor M.

3. A circuit for diagnosing a fault of an EPB caliper motor M according to claim 2, characterized in that: The EPB motor H-bridge driving module includes MOS tubes Q1 to Q4; The drain pins of the MOS tube Q3 and the MOS tube Q4 are both connected to the vehicle power supply line VBAT_MR, the gate pin of the MOS tube Q3 is connected to the drive signal port DRV_Q3 of the micro-control unit MCU, and the gate pin of the MOS tube Q4 is connected to the drive signal port DRV_Q4 of the micro-control unit MCU; The source pins of the MOS tube Q1 and the MOS tube Q2 are both connected to the ground, the gate pin of the MOS tube Q2 is connected to the drive signal port DRV_Q2 of the micro-control unit MCU, and the gate pin of the MOS tube Q1 is connected to the drive signal port DRV_Q1 of the micro-control unit MCU.

4. A circuit for diagnosing a fault of an EPB caliper motor M according to claim 3, characterized in that: The source of MOS tube Q3 is connected to the positive terminal EPB_L+ of EPB caliper motor M, the source of MOS tube Q4 is connected to the negative terminal EPB_L- of EPB caliper motor M, the drain pin of MOS tube Q2 is connected to the positive terminal EPB_L+ of EPB caliper motor M, and the drain pin of MOS tube Q1 is connected to the negative terminal EPB_L- of EPB caliper motor M.

5. A circuit for diagnosing a fault of an EPB caliper motor M according to claim 2, characterized in that: The first load diagnosis module in the EPB motor load diagnosis part includes a compound transistor U1, which is composed of two transistors connected, the emitter of the first transistor of the compound transistor U1 is grounded, the base of the first transistor is connected to the drive signal port M_DRV_EPB_L+ of the micro-control unit MCU, the collector of the first transistor is connected to the base of the second transistor, the emitter of the second transistor is connected to the power supply, the collector of the second transistor is connected to the positive terminal EPB_L+ of the EPB caliper motor M through the diode D1 and the resistor R5 in sequence, the resistor R1 and the capacitor C1 are connected in parallel and then connected in series with the resistor R3 between the positive terminal EPB_L+ of the EPB caliper motor M and the ground, and an analog-to-digital conversion port M_AD_EPB_L+ connected to the micro-control unit MCU is led out between the resistor R1 and the resistor R3.

6. A circuit for diagnosing a fault of an EPB caliper motor M according to claim 2, characterized in that: The second load diagnosis module in the EPB motor load diagnosis part includes a compound transistor U2, which is composed of two transistors connected, the emitter of the first transistor of the compound transistor U2 is grounded, the base of the first transistor is connected to the drive signal port M_DRV_EPB_L- of the micro-control unit MCU, the collector of the first transistor is connected to the base of the second transistor, the emitter of the second transistor is connected to the power supply, the collector of the second transistor is connected to the positive terminal EPB_L- of the EPB caliper motor M through the diode D2 and the resistor R6 in sequence, the resistor R2 and the capacitor C2 are connected in parallel and then connected in series with the resistor R4 between the positive terminal EPB_L- of the EPB caliper motor M and the ground, and an analog-to-digital conversion port M_AD_EPB_L- connected to the micro-control unit MCU is led out between the resistor R2 and the resistor R4.

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