Method for monitoring the safety of an electronic clutch position

Abstract

The application provides a kind of electronic clutch position safety monitoring method, provides electronic clutch, electronic clutch is converted into the linear motion of fork by gear set and camshaft The rotation of motor is pushed to the combination or disengagement of synchronizer ring, so as to control whether the output of electric axle end torque to wheel end;Motor is provided with sensor, sensor is used to obtain the relative position of motor;First safety check of hardware safety monitoring to motor, sensor;The moving track of motor is obtained, and the second safety check is carried out according to different positions in the moving track of motor.The application can realize the monitoring scheme of high functional safety level of electronic clutch position signal only through the sensor at the electronic clutch, and reduces the hardware cost.

Description

Technical Field

[0001] This invention relates to the field of vehicle functional safety technology, and in particular to a method for monitoring the position safety of an electronic clutch. Background Technology

[0002] Electric vehicles typically use the rear axle as the constant power source for all-wheel drive, while the front axle requires power output only when needed. When switching from four-wheel drive to two-wheel drive, there are three common implementation methods: First, the front axle drive motor uses zero-torque control, outputting no torque in two-wheel drive mode. The advantage of zero-torque control is reduced vehicle weight, saving on parts and development costs, but it also reduces driving range. Second, the front axle drive motor is replaced with an asynchronous motor. The advantage of asynchronous motors is that they do not generate braking torque during reverse towing, thus eliminating the need for additional control strategies. However, asynchronous motors are less efficient than synchronous motors, and using two different drive motors requires significant development costs. Third, a disengagement device is added to the front axle, allowing it to disengage as needed to conserve battery power. This article discusses an electronic clutch (eClutch).

[0003] The mechanical structure of an electronic clutch, such as Figure 1 As shown, its working principle is as follows: the motor converts the rotational motion of the motor into the linear motion of the shift fork through a two-stage parallel gear reduction and a camshaft, which drives the synchronizing ring of the synchronizer to engage and disengage, thereby controlling whether the torque at the electric shaft end is output to the wheel end. To meet the high functional safety level, the electronic clutch has two position sensors: one is a three-phase Hall sensor for detecting the position of the motor rotor, and the other is a PWM sensor for detecting the position of the shift fork.

[0004] The two signals are used to determine the absolute position of the electronic clutch and achieve a high level of functional safety through a rationality check. However, the addition of a PWM sensor will undoubtedly increase hardware costs.

[0005] To address the aforementioned issues, a novel method for monitoring the position safety of electronic clutches is needed. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for monitoring the position safety of an electronic clutch, which solves the problem that the addition of a PWM sensor increases hardware costs in the prior art, which uses two signals to determine the absolute position of the electronic clutch and achieve a high functional safety level.

[0007] To achieve the above and other related objectives, the present invention provides a method for monitoring the position safety of an electronic clutch, comprising:

[0008] Step 1: Provide an electronic clutch, which converts the rotational motion of the motor into the linear motion of the shift fork through a gear set and a camshaft, thereby driving the synchronizer ring of the synchronizer to engage or disengage, thus controlling whether the torque at the electric shaft end is output to the wheel end.

[0009] A sensor is installed at the motor, and the sensor is used to obtain the relative position of the motor;

[0010] Step 2: Perform the first security check on the motor and the sensor for hardware security monitoring;

[0011] Step 3: Obtain the movement trajectory of the motor, and perform a second safety check based on different positions in the movement trajectory of the motor.

[0012] Preferably, the motor in step one is a brushless DC motor.

[0013] Preferably, the sensor in step one is a three-phase Hall sensor.

[0014] Preferably, the first security check in step two includes at least one of power supply monitoring, output sequence rationality monitoring, and invalid Hall signal monitoring for the three-phase Hall sensor.

[0015] Preferably, the first security verification in step two includes at least one of the following: power supply monitoring of the motor drive module, motor voltage short circuit monitoring, motor overcurrent monitoring, motor overtemperature monitoring, and motor drive chip monitoring.

[0016] Preferably, the first and second security checks in steps two and three are integrated into a microcontroller.

[0017] Preferably, the microcontroller includes a functional layer and a functional monitoring layer, wherein the functional monitoring layer is used to obtain the relative position of the motor based on the signals from the sensor.

[0018] Preferably, the movement trajectory of the electronic clutch in step one is Z-shaped. The initial position of the motor is defined as the disengagement fulcrum, the position of the upper turning point of the movement trajectory is the synchronization start point, the position between the synchronization start point and the disengagement fulcrum is the disengagement point, the position of the lower turning point of the movement trajectory is the synchronization end point, the position between the synchronization end point and the synchronization start point is the synchronization contact point, the end point of the movement trajectory is the gear fulcrum, and the position between the synchronization end point and the gear fulcrum is the gear point.

[0019] Preferably, the method for the second safety verification in step three includes: determining whether the motor has reached the position of the disengagement fulcrum; if yes, recording the disengagement fulcrum stop information of the motor at this time, and sending a disengagement fulcrum learning success flag to the functional layer; if no, controlling the motor to move towards the position of the disengagement fulcrum; determining whether the motor has reached the position of the in-gear fulcrum; if yes, recording the in-gear fulcrum stop information of the motor at this time, and sending an in-gear fulcrum learning success flag to the functional monitoring layer; if no, controlling the motor to move towards the position of the in-gear fulcrum; determining whether the movement trajectory between the disengagement fulcrum and the in-gear fulcrum conforms to a preset value; if yes, ending the second safety verification; if no, the motor enters a fault response mode.

[0020] Preferably, the second safety verification method in step three further includes: determining whether the travel distance of the movement trajectory meets the preset value; and determining whether the position self-learning time of the motor meets the preset value.

[0021] As described above, the electronic clutch position safety monitoring method of the present invention has the following beneficial effects:

[0022] This invention provides a high-functional-safety-level monitoring solution for the electronic clutch position signal using only a sensor at the electronic clutch, thereby reducing hardware costs. Attached Figure Description

[0023] Figure 1 The diagram shown is a schematic diagram of the electronic clutch structure of the present invention;

[0024] Figure 2 The diagram shows the movement trajectory of the electronic clutch of the present invention.

[0025] Figure 3 The diagram shows a method for monitoring the position safety of the electronic clutch according to the present invention. Detailed Implementation

[0026] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0027] Please see Figure 3 The present invention also provides a method for monitoring the position safety of an electronic clutch, comprising:

[0028] Step 1: Provide an electronic clutch. The electronic clutch converts the rotational motion of the motor 101 into the linear motion of the shift fork through the gear set 102 and the camshaft 104, which drives the synchronization ring of the synchronizer 107 to engage or disengage, thereby controlling whether the torque at the electric axle end is output to the wheel end.

[0029] A sensor 108 is installed at the motor, which is used to obtain the relative position of the motor 101;

[0030] In an embodiment of the present invention, please refer to Figure 1 The electronic clutch in step one includes a motor 101, a first gear connected to the output shaft of the motor 101, a camshaft 104, and a synchronizer 107. A second gear that meshes with the gear set is fixedly connected to the camshaft 104, and a shift groove 103 is also provided on the camshaft 104. The synchronizer 107 includes a shift fork 106, a shift pin 105, and a synchronizer ring. One end of the shift pin 105 forms a sliding fit with the shift groove 103, and the other end of the shift pin 105 is fixedly connected to one side of the shift fork 106. The synchronizer ring is fixedly connected to the other side of the shift fork 106. A first sensor 108 for obtaining the rotor position is provided at the motor 101. The motor 101 converts its rotational motion into the linear motion of the shift fork 106 through the first gear and the camshaft 104, so that the synchronizer ring engages or disengages with the drive shaft of the corresponding wheel, thereby controlling the torque output of the wheel.

[0031] In an embodiment of the present invention, the motor 101 in step one is a brushless DC motor.

[0032] In an embodiment of the present invention, the sensor 108 in step one is a three-phase Hall sensor.

[0033] In an embodiment of the present invention, please refer to Figure 2 In step one, the movement trajectory of the electronic clutch is Z-shaped. The initial position of the motor 101 is defined as the disengagement fulcrum 201. The position of the upper turning point of the movement trajectory is the synchronization start point 203. The position between the synchronization start point 203 and the disengagement fulcrum 201 is the disengagement point 202. The position of the lower turning point of the movement trajectory is the synchronization end point 205. The position between the synchronization end point 205 and the synchronization start point 203 is the synchronization contact point 204. The end point of the movement trajectory is the gear fulcrum 207. The position between the synchronization end point 205 and the gear fulcrum 207 is the gear point 206.

[0034] Step 2: Perform the first security check on the motor 101 and sensor 108 for hardware security monitoring;

[0035] In an embodiment of the present invention, the first security check in step two includes at least one of power supply monitoring of the three-phase Hall sensor, output sequence rationality monitoring, and invalid Hall signal monitoring.

[0036] In an embodiment of the present invention, the first security verification in step two includes at least one of the following: monitoring the power supply of the drive module of motor 101, monitoring the short circuit of motor voltage, monitoring the overcurrent of motor, monitoring the overtemperature of motor, and monitoring the motor drive chip.

[0037] Step 3: Obtain the movement trajectory of motor 101, and perform a second safety check based on different positions in the movement trajectory of motor 101.

[0038] In an embodiment of the present invention, the first and second security checks in steps two and three are integrated into a microcontroller.

[0039] In an embodiment of the present invention, the microcontroller includes a functional layer and a functional monitoring layer, wherein the functional monitoring layer is used to obtain the relative position of the motor based on the signals from the sensors.

[0040] In an embodiment of the present invention, the method for the second security verification includes:

[0041] Self-learning of the 201st pivot point:

[0042] Determine whether motor 101 has reached the position of disengagement pivot 201. If yes, record the stop information of disengagement pivot 201 of motor 101 at this time, and send the disengagement pivot 201 learning success flag to the functional layer; otherwise, control motor 101 to move to the position of disengagement pivot 201.

[0043] Self-learning of Pivot Point 207 in the archives:

[0044] Determine whether motor 101 has reached the position of the pivot point 207. If yes, record the stop information of the pivot point 207 of motor 101 at this time, and intend to learn the successful flag bit of the pivot point 207 to the functional monitoring layer; if no, control motor 101 to move to the position of the pivot point 207.

[0045] Verification of the reasonableness of self-learning results:

[0046] If the movement trajectory between the disengagement fulcrum 201 and the engagement fulcrum 207 conforms to the preset value, the second safety check ends; otherwise, the motor 101 enters the fault response mode. That is, the high-functional safety level monitoring scheme of the electronic clutch position signal can be realized by only the sensor 108 at the electronic clutch, which reduces the hardware cost.

[0047] In other words, the absolute zero position is determined through the self-learning of the electronic clutch in this invention. To ensure that the absolute zero position of the motor 101 meets the required functional safety level, the absolute zero point also needs to inherit the highest functional safety level of the position signal.

[0048] The absolute zero position monitoring is decomposed into the Automotive Safety Integrity Level (ASIL). The functional layer controls the motor 101 to perform self-learning, and then performs travel distance verification at the upper and lower dead points (i.e., the dead point of the disengaged pivot 201 and the dead point of the in-gear pivot 207) to ensure the rationality of the self-learning results. The functional monitoring layer participates in the self-learning process of the motor 101 and performs travel distance verification at the upper and lower dead points to ensure that the position signal can reach a higher automotive safety integrity level. Finally, the functional layer and the functional monitoring layer jointly ensure that the absolute zero position obtained by self-learning meets the highest functional safety level.

[0049] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0050] In summary, this invention achieves a high-functional-safety-level monitoring scheme for the electronic clutch position signal using only a sensor at the electronic clutch, thus reducing hardware costs. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and has high industrial applicability.

[0051] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for monitoring the position safety of an electronic clutch, characterized in that, include: Step 1: Provide an electronic clutch, which converts the rotational motion of the motor into the linear motion of the shift fork through a gear set and a camshaft, thereby driving the synchronizer ring of the synchronizer to engage or disengage, thus controlling whether the torque at the electric shaft end is output to the wheel end. A sensor is installed at the motor to obtain the relative position of the motor; the movement trajectory of the electronic clutch is Z-shaped, the initial position of the motor is defined as the disengagement fulcrum, the position of the upper turning point of the movement trajectory is defined as the synchronization start point, the position between the synchronization start point and the disengagement fulcrum is defined as the disengagement point, the position of the lower turning point of the movement trajectory is defined as the synchronization end point, the position between the synchronization end point and the synchronization start point is defined as the synchronization contact point, the end point of the movement trajectory is defined as the gear fulcrum, and the position between the synchronization end point and the gear fulcrum is defined as the gear point; Step 2: Perform the first security check on the motor and the sensor for hardware security monitoring; The first security check includes at least one of the following: power supply monitoring of the motor drive module, motor voltage short circuit monitoring, motor overcurrent monitoring, motor overtemperature monitoring, and motor drive chip monitoring. Step 3: Obtain the movement trajectory of the motor, and perform a second safety check based on different positions in the movement trajectory of the motor; The second safety verification includes: performing self-learning of the motor's disengagement fulcrum and in-gear fulcrum, and determining whether the movement trajectory between the disengagement fulcrum and the in-gear fulcrum conforms to a preset value.

2. The method for monitoring the position safety of an electronic clutch according to claim 1, characterized in that: The motor mentioned in step one is a DC brushless motor.

3. The method for monitoring the position safety of an electronic clutch according to claim 1, characterized in that: The sensor mentioned in step one is a three-phase Hall sensor.

4. The method for monitoring the position safety of an electronic clutch according to claim 3, characterized in that: The first security check in step two includes at least one of the following: power supply monitoring of the three-phase Hall sensor, output sequence rationality monitoring, and invalid Hall signal monitoring.

5. The method for monitoring the position safety of an electronic clutch according to claim 3, characterized in that: The first and second security checks in steps two and three are integrated into a microcontroller.

6. The method for monitoring the position safety of an electronic clutch according to claim 5, characterized in that: The microcontroller in steps two and three includes a functional layer and a functional monitoring layer. The functional monitoring layer is used to obtain the relative position of the motor based on the signals from the sensors.

7. The method for monitoring the position safety of an electronic clutch according to claim 6, characterized in that: The second safety verification method in step three includes: determining whether the motor has reached the position of the disengagement fulcrum; if yes, recording the disengagement fulcrum stop information of the motor at this time and sending a disengagement fulcrum learning success flag to the functional layer; if no, controlling the motor to move towards the position of the disengagement fulcrum; determining whether the motor has reached the position of the in-gear fulcrum; if yes, recording the in-gear fulcrum stop information of the motor at this time and sending an in-gear fulcrum learning success flag to the functional monitoring layer; if no, controlling the motor to move towards the position of the in-gear fulcrum; determining whether the movement trajectory between the disengagement fulcrum and the in-gear fulcrum conforms to a preset value; if yes, ending the second safety verification; if no, the motor enters a fault response mode.

8. The method for monitoring the position safety of an electronic clutch according to claim 6, characterized in that: The second safety verification method in step three further includes: determining whether the travel distance of the movement trajectory meets the preset value; and determining whether the position self-learning time of the motor meets the preset value.

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