Vehicle Control System

Abstract

A vehicle control system (1) controls the drive of a vehicle (99), and comprises a drive source (15), a clutch (31, 32), a clutch actuator (35), and a control unit (50). The clutch (31, 32) is provided in a power transmission path from the drive source (15) to a driving wheel (11), and is capable of switching between power transmission engagement and disengagement. The clutch actuator (35) drives the clutch (31, 32). At least one location in which engagement occurs at an angle to a direction of rotation is provided between the clutch (31, 32) and the driving wheel (11). The control unit (50) controls the clutch actuator (35) to switch the clutch (31, 32) from a disengaged state to an engaged state, and to generate a load greater than a load required to engage the clutch (31, 32) during a transient torque input when a driving force is input from the drive source (15).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2022-149132, filed on September 20, 2022, the contents of which are incorporated herein by reference. [Technical Field]

[0002] The present disclosure relates to vehicle control systems. [Background technology]

[0003] Conventionally, there have been known control devices for controlling the drive of a vehicle. For example, in Patent Document 1, a dog clutch is provided as a controllable power connection / disconnection device between a second rotating machine that is a drive source and a reduction gear. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-123897 Summary of the Invention

[0005] In Patent Document 1, the location of the abnormality is identified from the rotation signal when the dog clutch is engaged and disengaged. Patent Document 1 does not mention clutch control other than abnormality detection and after abnormality detection. The purpose of the present disclosure is to provide a vehicle control system that can appropriately control the drive of a vehicle.

[0006] The vehicle drive system of the present disclosure controls the drive of a vehicle and includes a drive source, a clutch, a clutch actuator, and a control unit. The clutch is provided in a power transmission path from the drive source to the drive wheels and is capable of switching between connecting and disconnecting power transmission. The clutch actuator drives the clutch. The control unit controls the drive of the drive source and the clutch actuator.

[0007] nineAt least one meshing point is provided between the latch and the drive wheel at an angle relative to the direction of rotation. The control unit switches the clutch from a released state to an engaged state, and controls the clutch actuator so that a load greater than the load required to engage the clutch is generated when transient torque is input, inputting driving force from the drive source. When backlash elimination on the output side is completed, the load is reduced to place the clutch in an engaged and maintained state, and then the drive source is driven to generate torque. [Brief explanation of the drawings]

[0009] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: [Figure 1] FIG. 1 is a schematic diagram showing a vehicle control system according to a first embodiment; [Figure 2] FIG. 2 is a schematic diagram showing a clutch and a reducer according to a first embodiment; [Figure 3] FIG. 3 is a schematic diagram showing a clutch according to a first embodiment; [Figure 4] FIG. 4 is a diagram illustrating the removal of backlash according to the first embodiment; [Figure 5A] FIG. 5A is a diagram showing the relationship between the gear rotation angle and the output torque when backlash is not eliminated; [Figure 5B] FIG. 5B is a diagram showing the relationship between the gear rotation angle and the output torque when the backlash is eliminated; [Figure 6] FIG. 6 is a flowchart illustrating clutch control according to the first embodiment. [Figure 7] FIG. 7 is a schematic diagram showing a fitting portion of a drive shaft according to a second embodiment; [Figure 8A] FIG. 8A is a schematic diagram showing a clutch and a reducer according to a third embodiment; [Figure 8B] FIG. 8B is a schematic diagram showing meshing teeth of a clutch; [Figure 9] FIG. 9 is a schematic diagram showing a case where the reducer is a spur gear; [Figure 10] FIG. 10 is a flowchart illustrating clutch control according to the fourth embodiment. [Figure 11] FIG. 11 is a time chart illustrating clutch control according to the fourth embodiment. [Figure 12A] FIG. 12A is a schematic diagram showing a state in which a vehicle is climbing over a step; [Figure 12B] FIG. 12B is a schematic diagram showing a state in which the vehicle has climbed over a step; [Figure 13] FIG. 13 is a flowchart illustrating clutch control according to the fifth embodiment. [Figure 14] FIG. 14 is a time chart illustrating clutch control according to the fifth embodiment. [Figure 15] FIG. 15 is a flowchart illustrating the operation check process according to the sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle control system according to the present disclosure will be described below with reference to the accompanying drawings. In the following, substantially identical components in a plurality of embodiments will be designated by the same reference numerals, and descriptions thereof will be omitted.

[0011] The first embodiment is shown in Figures 1 to 6. As shown in Figure 1, a vehicle control device 30 is applied to a vehicle control system 1. The vehicle control system 1 includes a front wheel drive unit 10, a rear wheel drive unit 20, a clutch 31, a clutch actuator 35, a control unit 50, and the like.

[0012] The front-wheel drive unit 10 has a drive shaft 12 connected to the front wheels 11, a main motor 15, and a power transmission unit 18. The rear-wheel drive unit 20 has a drive shaft 22 connected to the rear wheels 21, a main motor 25, and a power transmission unit 28. The vehicle control system 1 of this embodiment is a so-called four-wheel drive system in which main motors 15, 25, which are drive sources, are provided on the front and rear wheel sides, respectively.

[0013] The main motors 15, 25 are so-called motor generators that function as electric motors that generate torque when supplied with power from a battery (not shown), and as generators that are driven when the vehicle 99 is braked and generate electricity. The driving force of the main motor 15 is transmitted to the drive shaft 12 via the power transmission unit 18, thereby driving and rotating the front wheels 11. The driving force of the main motor 25 is transmitted to the drive shaft 22 via the power transmission unit 28, thereby driving and rotating the rear wheels 21. The power transmission units 18, 28 are composed of a reducer, a differential device that absorbs the difference in rotation between the left and right wheels, and the like. Hereinafter, the front wheel drive unit 10 and the rear wheel drive unit 20 will be referred to as the "drive system," and the main motor will be referred to as the "MG."

[0014] The clutch 31 is provided in the front wheel drive unit 10 and is capable of switching between connection and disconnection of the main motor 15 and the front wheels 11. The clutch 31 may be provided anywhere in the power transmission path between the main motor 15 and the front wheels 11, and in this embodiment is provided between the main motor 15 and a reduction gear 41 (see FIG. 2, etc.) of the power transmission unit 18. For simplicity, FIG. 1 illustrates the clutch 31 as being provided on the drive shaft 12. The clutch actuator 35 applies a load to the clutch 31 to switch between an engaged state and a released state of the clutch 31.

[0015] 2 and 3, clutch 31 of this embodiment is a dog clutch (meshing clutch) and has bases 311, 313 and meshing teeth 312, 314. In this embodiment, meshing teeth 312, 314 are formed substantially perpendicular to the direction of rotation. Note that clutch 31 is not limited to a dog clutch, and may be a multi-plate or single-plate friction clutch.

[0016] 1, the control unit 50 is mainly composed of a microcomputer or the like, and includes a CPU, ROM, RAM, I / O, and bus lines connecting these components (none of which are shown). Each process in the control unit 50 may be software processing in which the CPU executes a program stored in advance in a physical memory device (i.e., a readable non-transitory tangible recording medium) such as a ROM, or may be hardware processing using a dedicated electronic circuit.

[0017] The control unit 50 acquires detection values ​​from current sensors 61, 63 that detect the current of the main motors 15, 25, rotation angle sensors 62, 64 that detect the rotation of the main motors 15, 25, a wheel speed sensor 65, and an accelerator position sensor (not shown) that detects the pedal position of the accelerator pedal 40, and controls the driving of the main motors 15, 25 and the clutch actuator 35. Although FIG. 1 shows the control unit 50 as being a single unit, the functions may be divided among multiple ECUs or the like. Also, to avoid complexity, some control lines have been omitted.

[0018] In a mechanism that transmits power via gears, shock occurs when the gears collide. It is possible to reduce the engagement shock through hardware, for example, by providing chamfers and a spring mechanism on the teeth of the dog clutch. However, a hardware-based approach to reducing the engagement shock increases the number of parts.

[0019] As shown in Figures 2 to 4, in this embodiment, the clutch 31 is provided between the main motor 15 and the reduction gear 41. The reduction gear 41 is made up of a helical gear. When the reduction gear 41 is pushed in the thrust direction as shown by arrow A1 in Figure 4, the helical gear rotates as shown by arrow A2, and the play between the gears is reduced. Hereinafter, the total play provided in the power transmission unit 18 and the like will be referred to as "backlash."

[0020] Therefore, in this embodiment, when transient torque is input, the clutch 31 is used to push the reduction gear 41 in the thrust direction, causing the helical gear to rotate. This makes it possible to eliminate backlash in the thrust direction and rotation direction. Also, as shown by arrow A3, inputting torque from the main motor 15 when backlash is eliminated suppresses rattle noise.

[0021] 5A and 5B, the horizontal axis represents the gear rotation angle on the input side of the reduction gear 41, and the vertical axis represents the torque output from the reduction gear 41. As shown in FIG. 5A, if there is no backlash on the output side of the reduction gear 41, the MG torque Tmg is not transmitted to the output side even if the input side is rotating, and when the backlash is eliminated, rattle noise occurs. The intensity of the rattle noise is approximately proportional to the amount of backlash. As shown in FIG. 5B, if there is backlash on the output side of the reduction gear 41, no rattle noise occurs, and torque is transmitted to the output shaft immediately after the main motor 15 is driven.

[0022] The clutch control of this embodiment will be described with reference to the flowchart of Fig. 6. This process is performed at a predetermined cycle by the control unit 50. Hereinafter, the "step" such as step S101 will be omitted and the step will simply be referred to as "S".

[0023] In S101, the control unit 50 determines whether or not transient torque is being input. Here, when the vehicle starts moving, i.e., when the main motor 15 is driven from a vehicle speed of 0 to generate MG torque, when coasting is switched to driving (acceleration), and when regeneration is switched to driving (acceleration), it is considered to be transient torque being input, and a positive determination is made. If it is determined that transient torque is not being input (S101: NO), the processing from S102 onwards is skipped. If the clutch 31 is to be engaged at a time other than transient torque being input, the drive of the clutch actuator 35 is controlled in a process separate from this process, and the clutch 31 is engaged. If it is determined that transient torque is being input (S101: YES), the processing proceeds to S102.

[0024] In S102, the control unit 50 drives the clutch actuator 35 to engage the clutch 31. In S103, the control unit 50 determines whether or not engagement of the clutch 31 has been completed. If it is determined that engagement of the clutch 31 has not been completed (S103: NO), the process returns to S102 and continues driving the clutch actuator 35. If it is determined that engagement of the clutch 31 has been completed (S103: YES), the process proceeds to S104.

[0025] In S104, the control unit 50 controls the clutch actuator 35 to apply a pressing force in the thrust direction, thereby eliminating backlash in the thrust direction, and also eliminating backlash in the rotational direction as the reduction gear 41 having helical teeth rotates (see FIG. 4).

[0026] In S105, the control unit 50 determines whether or not the removal of backlash has been completed. If it is determined that the removal of backlash has not been completed (S105: NO), the process returns to S104 and continues the pressing control in the thrust direction. If it is determined that the removal of backlash has been completed (S105: YES), the process proceeds to S106.

[0027] In S106, the control unit 50 releases the pressing force in the thrust direction and controls the driving of the clutch actuator 35 so that the pressing force is sufficient to maintain the engaged state of the clutch 31. Furthermore, if a locking mechanism (not shown) that maintains the engaged state of the clutch 31 is provided, the locking mechanism may be activated to turn off the power supply to the clutch actuator 35.

[0028] In S107, the control unit 50 drives the main motor 15 to generate torque. At this time, the output side is free of backlash, so rattle noise is suppressed. Note that the processing order of S106 and S107 may be reversed so that the thrust force is released after the main motor 15 starts to drive.

[0029] In this embodiment, when transient torque is input, a thrust force is generated in the engaged state of the clutch 31. If the reduction gear 41 has a helical gear, the thrust force is converted into a rotational force, thereby eliminating backlash in the thrust and rotation directions. By eliminating backlash before torque is generated by the main motor 15, rattle noise can be suppressed.

[0030] As described above, the vehicle control system 1 of this embodiment controls the driving of the vehicle 99 and includes the main motor 15, the clutch 31, the clutch actuator 35, and the control unit 50. The clutch 31 is provided in the power transmission path from the main motor 15 to the front wheels 11 and is capable of switching between connecting and disconnecting the power transmission. The clutch actuator 35 drives the clutch 31. The control unit 50 controls the driving of the main motor 15 and the clutch actuator 35.

[0031] The power transmission path has at least one location where the gears mesh at an angle relative to the direction of rotation. In this embodiment, the reduction gear 41 has a helical gear that meshes at an angle relative to the direction of rotation. The control unit 50 switches the clutch 31 from a released state to an engaged state, and controls the clutch actuator 35 so that a load greater than the load required to engage the clutch 31 is generated when a transient torque is input, which inputs driving force from the main motor 15.

[0032] As a result, by controlling the clutch 31, it is possible to appropriately control the drive of the vehicle 99. In detail, in this embodiment, when a load greater than that required for engagement is generated during transient torque input, and the clutch 31 is pressed in the thrust direction, the force in the thrust direction is converted into the rotational direction at the point where it engages at an angle. This makes it possible to eliminate backlash in the thrust direction and rotational direction. After the backlash has been eliminated, the normal engagement state is restored. This makes it possible to suppress the generation of rattle noise during transient torque input.

[0033] (Second embodiment, third embodiment) A second embodiment is shown in Fig. 7, and a third embodiment is shown in Figs. 8A and 8B. In the second embodiment, a diagonal groove d is formed in a fitting portion 121 between the clutch 31 and the drive shaft 12. Fig. 7 shows the drive shaft 12 side, and the fitting portion on the clutch 31 side is omitted.

[0034] In the third embodiment, as shown in Fig. 8A, the clutch 32 has bases 321 and 323 and meshing teeth 322 and 324. As shown in Fig. 8B, the meshing teeth 322 and 324 are formed to be inclined with respect to the direction of rotation.

[0035] As in the second and third embodiments, by forming a portion of the power transmission path from the clutch to the reduction gear where the gears mesh obliquely with respect to the direction of rotation, it is possible to convert the thrust force of the clutch actuator 35 into the direction of rotation. As a result, by controlling in the same way as in the first embodiment when transient torque is input, it is possible to eliminate backlash and suppress rattle noise when torque is input from the main motor 15.

[0036] Furthermore, when a structure for diagonal meshing is provided at a location other than the reduction gear as in the second or third embodiment, even if the reduction gear 42 is a spur gear, it is possible to eliminate backlash in the same way as in the first embodiment, as shown in Fig. 9. This configuration also achieves the same effects as the above embodiments.

[0037] (Fourth embodiment) A fourth embodiment is shown in Figures 10 and 11. When a vehicle 99 is traveling, resonance occurs when the fluctuation period of the cogging torque and torque ripple of the main motor 15 reaches a rotation speed corresponding to the resonance frequency of the drivetrain. Therefore, in this embodiment, when the torque fluctuation frequency of the main motor 15 is in the resonance range of the drivetrain, the clutch 31 is released and the vehicle travels using the driving force of the rear wheel drive unit 20. In other words, when the torque fluctuation frequency of the main motor 15 is in the resonance range of the drivetrain, the drivetrain is switched from four-wheel drive to two-wheel drive.

[0038] The clutch control of this embodiment will be described with reference to the flowchart of Fig. 10. In S201, the control unit 50 determines whether or not there is an engagement command for the clutch 31. It also determines whether or not there is an engagement command for the clutch 31. If it is determined that there is no engagement command for the clutch 31 (S201: NO), the processing from S202 onwards is skipped. If it is determined that there is an engagement command for the clutch 31 (S201: YES), the processing proceeds to S202.

[0039] In S202, the control unit 50 calculates the torque fluctuation frequency due to torque ripple and cogging torque based on the number of poles and the MG rotation speed Nmg of the main motor 15. Note that a plurality of torque fluctuation frequencies may be calculated, such as the fluctuation frequency due to torque ripple and the fluctuation frequency due to cogging torque.

[0040] In S203, it is determined whether the calculated torque fluctuation frequency corresponds to the resonant frequency of the drivetrain. Here, if the torque fluctuation frequency is within a predetermined range that includes the resonant frequency, a positive determination is made. Hereinafter, the predetermined range that includes the resonant frequency is referred to as the "resonant region" where appropriate. If it is determined that the torque fluctuation frequency corresponds to the resonant frequency of the drivetrain (S203: YES), the process proceeds to S204. If it is determined that the torque fluctuation frequency does not correspond to the resonant frequency of the drivetrain (S203: NO), the process proceeds to S205.

[0041] In S204, the control unit 50 disengages the clutch 31 to set the vehicle in two-wheel drive mode using the rear-wheel drive unit 20. In S205, the control unit 50 engages the clutch 31 to set the vehicle in four-wheel drive mode.

[0042] The clutch control of this embodiment will be described based on the time chart in FIG. 11. In FIG. 11, the horizontal axis represents a common time axis, and from the top to bottom, vehicle speed, MG rotation speed, clutch stroke, and drive torque are shown. Here, the rotation speed of the main motor 15 on the front wheel side is Nmg_f, and the drive torque is Td_f, as indicated by a solid line. The rotation speed of the main motor 25 on the rear wheel side is Nmg_r, and the drive torque is Td_r, as indicated by a dashed line. Note that this specification mainly describes the operation of the front wheel side where the clutch 31 is provided, and the subscripts _f and _r are omitted unless it is necessary to distinguish from the rear wheel side. In FIG. 11, the front and rear wheel distribution ratio of drive torque during four-wheel drive is shown as 1:1, but the front and rear wheel distribution ratio may be a ratio other than 1:1.

[0043] Before time x10, the MG rotation speed Nmg is smaller than the rotation speed region where the torque fluctuation frequency corresponds to the resonance region of the front wheel drive unit 10 (hereinafter simply referred to as the "resonance region"), so the clutch 31 is engaged and the MG rotation speed Nmg is set to a rotation speed corresponding to the vehicle speed. At this time, the total torque Td_t is distributed to the main motors 15, 25.

[0044] At time x10, when the MG rotational speed Nmg_f corresponding to the vehicle speed enters the resonance region, the clutch 31 is released and the rotational speed of the main motor 15 is set to 0. In other words, because the front drive torque Td_f becomes 0, the main motor 25 is controlled so that the total torque Td_t is output to the rear wheels. By releasing the clutch 31 between time x10 and time x11, when the torque fluctuation frequency enters the resonance region when the main motor 15 is driven, resonance in the front wheel drive unit 10 is suppressed, so that even if vibration occurs on the rear wheel drive unit 20 side, the total amount of vibration can be reduced. Note that if the resonance frequency characteristics of the front wheel drive unit 10 and the rear wheel drive unit 20 are different, the resonance region of the rear wheel drive unit 20 will be different from the resonance region of the front wheel drive unit 10.

[0045] At time x11, when the MG rotation speed Nmg corresponding to the vehicle speed exceeds the resonance region, the clutch 31 is engaged to drive the main motor 15. Also, at time x11, a transient torque is input, so the control of the first embodiment may be performed. After time x11, the total torque Td_t is distributed to the main motors 15, 25.

[0046] As a result, by controlling the clutch 31, it is possible to appropriately control the drive of the vehicle 99. In particular, in this embodiment, the control unit 50 releases the clutch 31 when the torque fluctuation frequency of the main motor 15 is in the resonance region of the drive shaft 12 connected to the front wheels 11. This makes it possible to reduce vibration of the vehicle 99.

[0047] (Fifth embodiment) 12A to 14 show a fifth embodiment. In this embodiment, the control when going over a step, especially immediately after going over the step, will be mainly described. Note that the control up until going over the step is not important.

[0048] 12A and 12B schematically show vehicle 99 going over a bump, with block arrows indicating the driving forces of front-wheel drive unit 10, rear-wheel drive unit 20, and the vehicle as a whole. For example, when going over a bump in a situation where the driver's intentions are not easily reflected, such as during automatic driving of an electric vehicle, it is necessary to reduce MG torque Tmg after going over the bump to suppress excessive acceleration and a sudden feeling of the vehicle coming out from the bump. In this embodiment, after the bump has been passed over, MG torque Tmg is reduced and clutch 31 is disengaged, thereby further suppressing the feeling of the vehicle coming out from the bump.

[0049] The clutch control of this embodiment will be described with reference to the flowchart in Fig. 13. In S301, the control unit 50 determines whether or not there is a step on the travel route. If it is determined that there is no step (S301: NO), the processing from S302 onwards is skipped. In S302, the drive of the main motor 15 is controlled so that the vehicle 99 can overcome the step.

[0050] In S303, the control unit 50 determines whether the vehicle 99 has gone over a step. If it is determined that the vehicle 99 has not gone over a step (S303: NO), the process returns to S302 and the step-over-step control continues. If it is determined that the vehicle 99 has gone over a step (S303: YES), the process proceeds to S304.

[0051] The control unit 50 releases the clutch 31 in S304 and controls the MG rotation speed in S305. When the clutch 31 is released and the load is removed, the MG rotation speed Nmg increases, so the control unit 50 controls the MG rotation speed Nmg so that it becomes a value obtained by converting the tire rotation speed Nt corresponding to the vehicle speed when traveling with creep torque into the gear ratio of the reduction gear, for example.

[0052] In S306, the control unit 50 adjusts the MG rotation speed Nmg to the target rotation speed Nmg * Here, it is determined whether the target rotation speed Nmg * If the MG rotation speed Nmg falls within a predetermined range including the target rotation speed Nmg, the determination is affirmative. * If it is determined that the MG rotation speed Nmg has not reached the target rotation speed (S306: NO), the process returns to S305 and continues MG rotation speed control. If it is determined that the MG rotation speed Nmg has reached the target rotation speed (S306: YES), the process proceeds to S307.

[0053] In S307, the control unit 50 determines whether the vehicle speed V is equal to or less than the vehicle speed determination threshold Vth. If it is determined that the vehicle speed V is greater than the vehicle speed determination threshold Vth (S307: NO), the process proceeds to S308, where brake control is performed to reduce the vehicle speed V. If it is determined that the vehicle speed V is equal to or less than the vehicle speed determination threshold Vth (S307: YES), the process proceeds to S309, where the clutch 31 is engaged.

[0054] Clutch control after going over a bump will be explained based on the time chart in Figure 14. In Figure 14, the horizontal axis represents a common time axis, and from the top, the horizontal axis represents the accelerator opening, MG torque, clutch stroke, brake torque, MG rotation speed, and tire rotation speed.

[0055] At time x50, when the front wheels 11 go over the step, the driver reduces the pedal pressure, reducing the accelerator opening and decreasing the MG torque Tmg. When it is determined at time x51 that the step has been passed, the clutch 31 is released. This makes it possible to suppress the feeling of the vehicle suddenly jumping out after passing over the step.

[0056] When the clutch 31 is released at time x51, the MG rotation speed Nmg increases, and the MG rotation speed Nmg reaches the target rotation speed Nmg. * The MG rotation speed is controlled so that the MG rotation speed Nmg is equal to the target rotation speed Nmg * At time x53, after the tire rotation speed Nt reaches the tire rotation speed threshold value TH, the clutch 31 is engaged and normal control is restored.

[0057] As a result, by controlling the clutch 31, it is possible to appropriately control the drive of the vehicle 99. In detail, in this embodiment, the control unit 50 determines whether the front wheels 11 are going over a step, and if it is determined that the step has been gone over, it releases the clutch 31. After the step has been gone over, the clutch 31 is released and the main motor 15 and the drive shaft 12 are separated, thereby suppressing sudden acceleration after the step has been gone over. This further improves the vehicle stability after going over the step.

[0058] (Sixth embodiment) A sixth embodiment is shown in Fig. 15. In this embodiment, the clutch 31 is released to check the operation of the main motor 15 while the vehicle is stopped. The operation check process of this embodiment will be described with reference to the flowchart in Fig. 15. This process is performed when an operation check is performed after the vehicle system is started or before the vehicle system is stopped.

[0059] In S401, the control unit 50 determines whether the vehicle speed is 0, the brake is ON, and the vehicle is in a stopped state. If it is determined that the vehicle is not in a stopped state (S401: NO), the processing from S402 onwards is skipped. If it is determined that the vehicle is in a stopped state (S401: YES), the processing proceeds to S402.

[0060] In S402, the control unit 50 confirms that the clutch 31 is engaged, and in S403, it drives the clutch actuator 35 to release the clutch 31. In S404, the control unit 50 performs an abnormality diagnosis on the clutch 31 based on the detected value of the stroke sensor and the detected value of the current sensor of the clutch actuator 35, etc. If the clutch 31 is a friction clutch, the detected value of a load sensor may be used instead of the stroke sensor. Here, the control unit 50 diagnoses abnormalities in the stroke sensor or load sensor, abnormalities in the clutch actuator 35, and sticking or release abnormalities in the clutch 31. In the abnormality diagnosis, for example, the difference between the detected value and the target value is calculated, and if it is within an allowable range, it is determined to be normal, and if it is not within the allowable range, it is determined to be abnormal. The same applies to S408.

[0061] In S405, the control unit 50 determines whether or not the release of the clutch 31 is complete. If it is determined that the clutch 31 is not released (S405: NO), the process returns to S403 and the release drive of the clutch actuator 35 continues. If it is determined that the release of the clutch 31 is complete (S405: YES), the process proceeds to S406.

[0062] The control unit 50 confirms in S406 that the MG rotation speed Nmg is 0, and in S407, the control unit 50 determines whether the MG rotation speed Nmg is equal to or exceeds the target rotation speed Nmg * In S408, the control unit 50 performs an abnormality diagnosis on the main motor 15 based on the detected value of the rotation angle sensor and the detected value of the current sensor of the main motor 15. Here, the main motor 15 is diagnosed for abnormalities in rotation speed and output.

[0063] In S409, the control unit 50 adjusts the MG rotation speed Nmg to the target rotation speed Nmg *It is determined whether the MG rotation speed Nmg has reached the target rotation speed Nmg * If it is determined that the MG rotation speed Nmg has not reached the target rotation speed Nmg (S409: NO), the process returns to S407 and the driving of the main motor 15 continues. * If it is determined that the number of times has reached the predetermined number (S409: YES), the process proceeds to S410.

[0064] In S410, the control unit 50 stops driving the main motor 15 and engages the clutch 31. In S411, the control unit 50 sets the driving mode to the standby mode. Note that if an abnormality is detected in S404 or S408, the control unit 50 transitions to fail-safe control.

[0065] In this embodiment, the control unit 50 performs abnormality diagnosis by disengaging the clutch 31 while the front wheels 11 are not rotating and driving the main motor 15. By driving the main motor 15 with the clutch 31 in the disengaged state, abnormality diagnosis can be performed without moving the vehicle 99.

[0066] In this embodiment, the clutch 31 is provided in the front wheel drive unit 10, the front wheels 11 correspond to the "drive wheels", the drive shaft 12 corresponds to the "drive shaft", and the main motor 15 corresponds to the "drive source". The fourth to sixth embodiments are considered as reference embodiments.

[0067] (Other embodiments) In the above embodiment, the clutch is provided in the front-wheel drive unit. In other embodiments, the clutch may be provided in the rear-wheel drive unit, or in both the front and rear-wheel drive units. When the clutch is provided in the rear-wheel drive unit, the rear wheels 21 correspond to the "drive wheels," the drive shaft 22 corresponds to the "drive shaft," and the main motor 25 corresponds to the "drive source." Furthermore, because the main motor can be rotated even when the drive wheels are stopped by disengaging both the brake and clutch of the two-speed transmission mechanism, application to a two-speed transmission mechanism is also possible.

[0068] In the above embodiments, the vehicle drive system is a so-called four-wheel drive system in which the main motor serving as the drive source is provided in the front-wheel drive unit and the rear-wheel drive unit. In other embodiments, the vehicle drive system may be a so-called two-wheel drive system in which the main motor is provided in either the front-wheel drive unit or the rear-wheel drive unit. While the respective embodiments can be implemented in combination, the fourth embodiment is applied to a four-wheel drive system.

[0069] The control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to execute one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer. As described above, the present disclosure is not limited to the above embodiments and can be implemented in various forms without departing from the spirit of the present disclosure.

[0070] The present disclosure has been described based on the embodiments. However, the present disclosure is not limited to the embodiments and structures. The present disclosure also encompasses various modifications and variations within the scope of equivalents. Furthermore, various combinations and forms, as well as other combinations and forms including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

[Claim 1] A vehicle control system for controlling the driving of a vehicle (99), A driving source (15); a clutch (31, 32) provided in a power transmission path from the drive source to the drive wheels (11) and capable of switching between connection and disconnection of power transmission; a clutch actuator (35) for driving the clutch; a control unit (50) that controls the driving of the drive source and the clutch actuator; Equipped with At least one meshing point is provided between the clutch and the drive wheel at an angle relative to the rotation direction, The control unit switches the clutch from a released state to an engaged state, and controls the clutch actuator so that a load greater than the load required to engage the clutch is generated when a transient torque is input that inputs driving force from the driving source, and when backlash elimination that eliminates play on the output side is completed, the control unit reduces the load to bring the clutch into an engaged and maintained state, and then drives the driving source to generate torque.

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