JP4513612B2 - Vehicle torque distribution control device - Google Patents

Description

  The present invention relates to a vehicle torque provided with left and right torque distribution control means for controlling torque distribution to the left and right wheels in accordance with torque output commands to both motors, wherein at least one of the left and right wheels is driven by two motors. It belongs to the technical field of distribution control devices.

  Conventionally, an engine, a first motor that is mechanically coupled to the engine and the front wheels and electrically coupled to the battery, and a first motor that is mechanically coupled to the rear wheels and electrically coupled to the battery. A hybrid four-wheel drive vehicle including two motors is known (for example, see Patent Document 1).

On the other hand, mechanical four-wheel drive vehicles that realize neutral steering by controlling the front-rear distribution at 30:70 to 70:30 and the rear-wheel left-right distribution at 100: 0 to 0: 100 are known (for example, Patent Document 2).
JP 2004-222413 A JP 2004-189067 A

  However, the system proposed in the prior art, for example, does not have a differential mechanism that accepts and absorbs the differential between the left and right rear wheels, but is hybridized with a rear wheel two-motor specification that drives the left and right rear wheels independently, When torque distribution control is performed on the left and right rear wheels, at least one of the two motors that drive the left and right rear wheels is abnormal (over-rotation or under-rotation), and at least of the two brake systems that brake the left and right rear wheels On the other hand, when there is a difference in the rotational speeds of the left and right wheels due to an abnormality in the brake system (under rotation due to drag frictional force), there is a problem that the straight traveling stability and the turning traveling stability may be lowered.

  The present invention has been made paying attention to the above problem, and can ensure straight running stability and turning travel stability when the motor and brake system are abnormal in which the left and right wheel speeds deviate from the target wheel speed. An object of the present invention is to provide a torque distribution control device.

In order to achieve the above object, in the present invention, at least one of the front and rear wheels is driven by two motors, and left and right torque distribution control for controlling torque distribution to the left and right wheels by a torque output command to both motors. In a vehicle with means,
An abnormality determining means is provided for determining an abnormality when the difference between the actual wheel speed of the left and right wheels and the target wheel speed is a specified value or more,
The left and right torque distribution control means executes an abnormal time corresponding torque distribution control that adjusts the torque distribution to the left and right wheels so that the actual wheel speed of the left and right wheels is returned to an appropriate value at the time of abnormality determination by the abnormality determination means. Features.

  Therefore, in the vehicle torque distribution control device according to the present invention, when the abnormality determination means determines that the difference between the actual wheel speed of the left and right wheels and the target wheel speed is greater than or equal to the specified value, In the distribution control means, an abnormal time corresponding torque distribution control for adjusting the torque distribution to the left and right wheels so as to return the actual wheel speed of the left and right wheels to an appropriate value is executed. For example, when only one of the left and right wheels is over-rotation abnormal, the wheel speed balance between the left and right wheels can be reduced by offsetting the torque distribution value to the normal wheel side or limiting the output of the motor that drives the abnormal wheel. Can be returned to an appropriate balance. As a result, it is possible to ensure straight running stability and cornering stability when the motor and brake system are abnormal in which the left and right wheel speeds deviate from the target wheel speed.

  Hereinafter, the best mode for carrying out a vehicle torque distribution control apparatus according to the present invention will be described based on a first embodiment shown in the drawings.

First, the configuration will be described.
FIG. 1 is an overall system diagram showing a hybrid four-wheel drive vehicle to which the torque distribution control device of Embodiment 1 is applied.
As shown in FIG. 1, the hybrid four-wheel drive vehicle of Embodiment 1 includes a CPU 101, an auxiliary battery 102, a high-power battery 301, an FR inverter 302, a first motor 303 (first motor), and a generator. 304, engine 305, power split mechanism 306, RR inverter 307, second motor 308 (second motor), third motor 309 (third motor), accelerator sensor 401, brake sensor 402, DC / DC converter 403, rudder angle sensor 404 (turning degree detecting means), GPS 405, and wheel speed sensor 406 are provided.

  The CPU 101 monitors the high-power battery 301, calculates the input / output possible electric energy according to the SOC, temperature, and deterioration state, and controls the FR inverter 302 based on this, thereby the first motor 303 (front drive) And the generator 304 are operated, and the engine 305 is controlled. Also, by controlling the RR inverter 307, the second motor 308 (for the right rear drive) and the third motor 309 (for the left rear drive) are operated to control the torque distribution control of the left and right rear wheels to achieve neutral steering ( Normal control). Then, based on the detection value from the rudder angle sensor 404, it is determined whether or not the vehicle is turning. Furthermore, GPS405 is used to collect terrain information and grasp the travel route. The detection value from the wheel speed sensor 406 is confirmed and each wheel speed is grasped.

  The auxiliary battery 102 serves to provide an operating power source for the CPU 101. In this system, power is supplied by a DC / DC converter 403 that uses a high-power battery 301 as a power source.

  The high-power battery 301 assists vehicle travel by supplying electric power to the first motor 303 via the FR inverter 302, and uses the electric power generated by the generator 304 via the RR inverter 307. Has the role of collecting. In addition, when the second motor 308 and the third motor 309 are powered, the vehicle is assisted by supplying electric power via the RR inverter 307, and the second motor 308 and the third motor 309 generate power. In this case, it also has a role of collecting power via the RR inverter 307.

  The FR inverter 302 is directly controlled by the CPU 101. The electric energy of the high-power battery 301 is supplied to the first motor 303 according to the generated torque and the rotational speed of the engine 305, and the electric energy generated by operating the generator 304 is returned to the high-power battery 301. The first motor 303, the generator 304, and the engine 305 are directly connected to the planetary gear mechanism (incorporated in the power split mechanism 306). It cannot be activated.

  The first motor 303 is for front drive and generates drive torque independently when the vehicle speed is low. Further, when the vehicle speed is high, the driving torque of the engine 305 is assisted. Further, when decelerating, it generates electric energy by generating power (regenerative action), and has the role of returning it to the high-power battery 301 via the FR inverter 302. Further, the control is applied with the motor rotation speed = vehicle speed. In addition, a temperature sensor is incorporated so that power input / output restriction (component protection) can be performed when the temperature rises, and the detection value is transmitted to the CPU 101.

  The generator 304 basically has no starter in a hybrid electric vehicle. At the start of the vehicle to which this system is applied, power is supplied from the high-power battery 301 and the engine 305 is started by operating as a motor. During normal travel, electric energy is generated (power generation) by balancing the first motor 303 and the engine 305 and is returned to the high-power battery 301. Sometimes, it is possible to cope with rapid acceleration by supplying the first motor 303 directly.

  The engine 305 is directly controlled by the CPU 101. Specifically, when the vehicle speed is high, torque is generated to drive the vehicle.

  The power split mechanism 306 has a planetary gear mechanism, and an engine 305 is directly connected to the carrier, a first motor 303 is connected to the ring gear, and a generator 304 is directly connected to the sun gear. The transmission equivalent of the conventional system is also configured inside.

  The RR inverter 307 is directly controlled by the CPU 101. It plays a role of supplying / recovering the electric energy of the high-power battery 301 according to the generated torque and the rotational speed of the second motor 308 and the third motor 309.

  The second motor 308 is in charge of right rear driving as a 4WD vehicle during normal traveling, and generates torque in the traveling course increase caused by the inner wheel difference during turning traveling, thereby contributing to improvement in traveling and steering stability. Then, the rotational speed is applied to the control as the rear right wheel speed. Further, during straight traveling, torque required for straight traveling is generated based on the relationship with the input / output possible torque of the third motor 309 (command is received via the CPU 101 → the RR inverter 307).

  The third motor 309 is in charge of left rear drive as a 4WD vehicle during normal travel, and generates torque in the travel course increase caused by the inner wheel difference during turning travel, thereby contributing to improved travel and steering stability. Then, the rotational speed is applied to the control as the rear left wheel speed. Further, during straight running, torque necessary for straight running is generated based on the relationship with the input / output possible torque of the second motor 308 (command is received via the CPU 101 → the inverter for RR 307).

  The accelerator sensor 401 transmits to the CPU 101 the amount of accelerator pedal stroke that the driver has depressed during acceleration.

  The brake sensor 402 transmits to the CPU 101 the brake pedal stroke amount that the driver has depressed when decelerating.

  The DC / DC converter 403 converts the energy from the high voltage battery 301 into 12V and supplies it to the auxiliary battery 102. That is, it has the same function as an alternator in a conventional engine vehicle.

  The steering angle sensor 404 has a function of transmitting a steering angle detected by a driver's steering operation to the CPU 101.

  The GPS (Global Positioning System) 405 extracts the corner turning radius, the gradient, and the estimated road surface μ that exist up to the destination, and presents each information to the CPU 101.

  The wheel speed sensor 406 is connected to the front two wheels, and transmits the detected value to the CPU 101 as the wheel speed.

  Next, the operation will be described.

[Right and left torque distribution control process for rear wheel]
FIG. 2 is a flowchart showing the flow of the left and right torque distribution control process for the rear wheels executed by the CPU 101 of the first embodiment. Each step will be described below (left and right torque distribution control means).

  In step S1, when the vehicle system is activated, the stored rear torque distribution learning value set last time is cleared, and the process proceeds to step S2.

  In step S2, following the clearing of the rear torque distribution learning value in step S1, the degree of turning is grasped from the detection value from the rudder angle sensor 404, and the motor rotation speeds of the second motor 308 and the third motor 309 (= left and right rear wheels). Wheel speed gap, which is the difference between the command value for the RR inverter 307 (= the target wheel speed of the left and right rear wheels) is greater than or equal to a specified value, and if yes, the process proceeds to step S4. If No, the process proceeds to step S3.

  In step S3, following the determination that the wheel speed gap between the left and right rear wheels is less than the specified value and normal in step S2, normal control (the outputs of the second motor 308 and the third motor 309 are implemented to achieve neutral steering). Torque distribution control of the left and right rear wheels by control) is executed, and the abnormality determination in step S2 is repeated.

  In step S4, following the determination that at least one wheel speed gap of the left and right rear wheels in step S2 is greater than or equal to the specified value, the rear torque distribution learning value already stored is the same as the current abnormality determination pattern. It is determined whether or not the learning value information in the abnormality determination pattern is present. If Yes, the process proceeds to step S17, and if No, the process proceeds to step S5.

  In step S5, following the determination that there is no learning value in step S4, it is determined whether there is one abnormal wheel among the left and right rear wheels. If Yes (one NG wheel), the process proceeds to step S6. In the case of (both wheels NG), the process proceeds to step S13.

  In step S6, following the determination of one NG wheel in step S5, it is determined whether or not the NG wheel is a right rear wheel. If Yes, the process proceeds to step S7, and if No, the process proceeds to step S10.

  In step S7, following the determination that the NG wheel is the right rear wheel in step S6, it is determined whether or not an overspeed abnormality has occurred in the right rear wheel. If yes, the process proceeds to step S8. In this case, the process proceeds to step S9.

In step S8, following the determination that an overspeed abnormality has occurred in step S7, the torque distribution value is offset to the left side or the output of the second motor 308 is limited to reduce the rotation speed of the right rear wheel. Then, the RR inverter 307 is controlled to return the rotation balance of the left and right rear wheels to an appropriate value, and the process proceeds to step S16.
Here, for example, if the torque distribution value is offset to the left during straight running, the left distribution rate exceeds 50% and the rear right rotation speed rotates by ΔN with respect to the rear left rotation speed as shown in FIG. The number will be reduced. Therefore, the offset amount of the torque distribution value is set to an amount that suppresses overrotation of the right rear wheel.
Further, for example, when the output of the second motor 308 is limited during straight traveling, the absolute value of the difference between the rear left rotation speed and the rear right rotation speed increases as the torque limit value increases as shown in FIG. growing. Therefore, the torque limit value of the second motor 308 is set to an amount that suppresses overrotation of the right rear wheel.
Further, the turning radius R is calculated by grasping the degree of turning from the rudder angle sensor 404, and as shown in FIG. Since the difference becomes large, the correction coefficient is set to a value larger than 1. By multiplying this correction coefficient, the offset amount of the torque distribution value and the torque limit value are corrected.

In step S9, following the determination that the underrotation abnormality has occurred in step S7, the torque distribution value is offset to the right side or the output of the second motor 308 is increased in order to increase the rotation speed of the right rear wheel. Alternatively, the RR inverter 307 is controlled so as to limit the output of the third motor 309, the rotation balance of the left and right rear wheels is returned to an appropriate value, and the process proceeds to step S16.
Here, for example, during straight running, the offset amount to the right side of the torque distribution value is set to an amount that suppresses the underrotation of the right rear wheel (FIG. 3).
Also, for example, during straight running, the torque increase value of the second motor 308 is set so that the rotation of the right rear wheel (under-rotation wheel) matches the rotation of the left rear wheel, and the torque of the third motor 309 The limit value is set so that the rotation of the left rear wheel matches the rotation of the right rear wheel (under rotation wheel) (FIG. 4).
Further, a correction coefficient is set according to the turning radius R, and the offset amount of the torque distribution value and the torque limit value are corrected using the set correction coefficient (FIG. 5).

  In step S10, following the determination that the NG wheel is the left rear wheel in step S6, it is determined whether an overspeed abnormality has occurred in the left rear wheel. If yes, the process proceeds to step S11. In this case, the process proceeds to step S12.

In step S11, following the determination that an overspeed abnormality has occurred in step S10, the torque distribution value is offset to the right or the output of the third motor 309 is limited to reduce the rotation speed of the left rear wheel. Then, the RR inverter 307 is controlled to return the rotation balance of the left and right rear wheels to an appropriate value, and the process proceeds to step S16.
Here, for example, during straight running, the amount of offset to the left of the torque distribution value is set to an amount that suppresses excessive rotation of the left rear wheel (FIG. 3).
Further, for example, during straight running, the torque limit value of the third motor 309 is set to an amount that suppresses over-rotation of the left rear wheel.
Further, a correction coefficient is set according to the turning radius R, and the offset amount of the torque distribution value and the torque limit value are corrected using the set correction coefficient (FIG. 5).

In step S12, following the determination that the underspeed abnormality has occurred in step S10, the torque distribution value is offset to the left side or the output of the third motor 309 is increased in order to increase the rotation speed of the left rear wheel. Alternatively, the RR inverter 307 is controlled so as to limit the output of the second motor 308, the rotation balance of the left and right rear wheels is returned to an appropriate value, and the process proceeds to step S16.
Here, for example, during straight running, the amount of offset to the left of the torque distribution value is set to an amount that suppresses under-rotation of the left rear wheel (FIG. 3).
Further, for example, during straight running, the torque increase value of the third motor 309 is set so that the rotation of the left rear wheel (under-rotation wheel) matches the rotation of the right rear wheel, and the torque of the second motor 308 The limit value is set so that the rotation of the right rear wheel matches the rotation of the left rear wheel (under rotation wheel) (FIG. 4).
Further, a correction coefficient is set according to the turning radius R, and the offset amount of the torque distribution value and the torque limit value are corrected using the set correction coefficient (FIG. 5).

In step S13, following the determination that both wheels are NG in step S5, it is determined whether or not correction is impossible. If Yes, the process proceeds to step S14, and if No, the process proceeds to step S15.
Here, “determination of whether correction is impossible” is performed based on whether or not the wheel speed gaps of the left and right rear wheels both exceed the limit specified value (> specified value). That is, it is determined that correction is possible when the wheel speed gap of one or both of the left and right rear wheels does not exceed the limit specified value.

  In step S14, following the determination that both the left and right rear wheels cannot be corrected in step S13 (travel stability cannot be maintained during power running / regeneration), the output / regeneration of the second motor 308 and the third motor 309 is performed. Is issued and the process proceeds to step S16.

In step S15, following the determination that both wheels are abnormal in step S13 but the degree of abnormality is low, control for correcting the offset amount of the torque distribution value and the torque limit value is applied to the RR inverter 307. Control goes to step S16.
Here, in the correction of the offset amount of the torque distribution value and the torque limit value, the above-described Step S8, Step S9, Step are performed so as to correct the rotational speed imbalance of the left and right rear wheels in consideration of an abnormal degree of left-right difference or the like. Of the methods of S11 and S12, the most preferable method is selected and executed.

  In step S16, following any one of step S8, step S9, step S11, step S12, step S14, and step S15, the torque adjustment result under each condition is stored, and the process returns to step S2 (torque adjustment result storage unit) ).

  In step S17, following the determination that there is a learned value in step S4, a torque command based on the learned value is output, and the process returns to step S2.

[Right wheel left and right torque distribution control operation]
When the wheel speed gap is less than the specified value and both the left and right rear wheels are normal, the process proceeds from step S1 to step S2 to step S3 in the flowchart of FIG. 2, and the flow of step S2 to step S3 is repeated. In order to realize neutral steer, torque distribution control of the left and right rear wheels by output control of the second motor 308 and the third motor 309 is executed.

  When the NG wheel is only the right rear wheel and an overspeed abnormality occurs, the flow proceeds to step S2, step S4, step S5, step S6, step S7, step S8 in the flowchart of FIG. Abnormal response torque distribution control is executed by offset setting or right output restriction setting.

  When the NG wheel is only the right rear wheel and under-rotation abnormality occurs, the process proceeds to step S2, step S4, step S5, step S6, step S7, step S9 in the flowchart of FIG. Abnormal torque response control is executed by offset setting, right output up or left output restriction.

  When the NG wheel is only the left rear wheel and an overspeed abnormality occurs, in the flowchart of FIG. 2, the process proceeds from step S1, step S2, step S4, step S5, step S6, step S10, step S11, and step S11. , The abnormal time corresponding torque distribution control by the right offset setting or the left output restriction setting is executed.

  When the NG wheel is only the left rear wheel and the under-rotation abnormality occurs, the process proceeds from step S2 to step S4 to step S5 to step S6 to step S10 to step S12 in the flowchart of FIG. Torque distribution control in response to an abnormality is executed by offset setting, left output increase, or right output restriction.

  When the NG wheels are both the left and right rear wheels and cannot be corrected, in the flowchart of FIG. 2, the process proceeds from step S2, step S4, step S5, step S13, step S14, and in step S14, the rear output / regeneration is performed. Torque distribution control in response to abnormality due to prohibition is executed.

  When the NG wheel is both the left and right rear wheels and can be corrected, in the flowchart of FIG. 2, the process proceeds to step S2, step S4, step S5, step S13, step S15, and in step S15, the offset / output restriction is performed. Torque distribution control in response to abnormality by value correction is executed.

  Then, in the case where the torque adjustment result under each condition is stored in step S16 by learning the torque distribution control for abnormality, the abnormality determination pattern similar to the current abnormality determination pattern in step S2 is stored. If the learned value information exists, the flow of steps S2 → S4 → step S17 is repeated in the flowchart of FIG. 2, and a torque command based on the learned value is output in step S17.

[Right wheel left / right torque distribution control]
For example, if the left and right rear wheels are connected to a single drive motor via a differential mechanism, even if an over-rotation abnormality or under-rotation abnormality occurs in a single drive motor, the differential function of the differential mechanism will advance straight When traveling, the left and right rear wheels have the same rotation speed.When turning, the left and right rear wheels can be differentially traced so that the turning line is traced according to the turning radius and the vehicle speed. Is secured.

  However, when the left and right rear wheels are driven by two independent motors, there is no differential function due to the differential mechanism, so there is a rotation difference between the left and right rear wheels (= motor rotation difference) due to an abnormality in one or both motors. Even if the steering angle is kept at the neutral position for the purpose of straight running, the left and right rear wheels behave like a gentle turn to the side with the lower wheel speed, and the straight running stability is improved. descend. In addition, even when turning, even if the torque distribution of the left and right rear wheels is controlled to achieve neutral steering, the steering characteristics tend to be understeer or oversteer due to the difference in rotation between the left and right rear wheels. The turning stability of the turn will be reduced. This decrease in running stability is not only when the drive motor is abnormal, but also when there is a difference in rotation between the left and right rear wheels due to an abnormality in the brake system, such as brake dragging on one of the left and right rear wheels. is there.

  In contrast, in the first embodiment, the wheel speed gap between each motor rotation number (actual wheel speed) for driving the left and right rear wheels and a command value (target wheel speed) for each motor 308, 309 for driving the left and right rear wheels is set to the left and right. Determine each wheel and determine whether there is an abnormality for each of the left and right wheels when the wheel speed gap is greater than or equal to the specified value.When determining the abnormality, return the actual wheel speed of the left and right rear wheels to the appropriate value. By executing the torque distribution control for abnormal situations that adjusts the torque distribution, when wheel speed variation occurs on the left and right rear wheels due to abnormalities in the drive motor, brake system, etc., the impact on straight traveling performance and turning traveling performance is affected. This eliminates the possibility of safe driving.

  For example, if an abnormality occurs due to over- or under-rotation in one of the left and right rear wheels, an offset setting for the left and right rear wheel torque distribution ratio and a torque limit value for the motor output torque that drives one of the left and right rear wheels The right / left rear wheel rotation speed balance can be maintained at an appropriate value by setting the left and right rear wheels to ensure straight running performance and turning performance even if an abnormality occurs in one of the left and right rear wheels. Can do.

  Also, when an abnormality has occurred in both the left and right rear wheels and the degree of abnormality is so small that it can be corrected, the right and left rear wheel torque distribution ratio offset setting, By setting the torque limit value of the motor output torque that drives one of the left and right rear wheels, it is possible to maintain the right and left rear wheel rotation speed balance at an appropriate value, which causes abnormalities in the left and right rear wheels. In addition, straight traveling performance and turning traveling performance can be ensured.

  Furthermore, when an abnormality occurs in both the left and right rear wheels, and the degree of abnormality exceeds the correction level, it is determined that running stability and power regeneration cannot be maintained if both motors 308 and 309 are used. Since the output / regeneration is prohibited, the vehicle is a front wheel drive vehicle in which only the left and right front wheels are the driving wheels and the left and right rear wheels are the driven wheels. This causes an uncorrectable abnormality in the left and right rear wheels. In addition, straight traveling performance and turning traveling performance can be ensured.

  In addition, in a driving situation where the motor abnormality or brake system abnormality does not change, the control becomes complicated by setting the torque distribution ratio offset or setting the torque limit value each time a wheel speed gap occurs. Become. On the other hand, once the rear torque distribution learning value is stored and set, various determination processes and setting processes can be performed by using the rear torque distribution learning value as long as the wheel speed gap occurrence state is the same. This can be omitted, and the control becomes simple, and the stable torque handling control corresponding to the occurrence of the same abnormality can be achieved.

Next, the effect will be described.
In the vehicle torque distribution control apparatus according to the first embodiment, the following effects can be obtained.

  (1) In a vehicle equipped with left and right torque distribution control means for controlling torque distribution to the left and right wheels in accordance with torque output commands to both motors, at least one of the front and rear wheels is driven by two motors. An abnormality determining means (step S2) for determining an abnormality when the difference between the actual wheel speed of the wheel and the target wheel speed is a specified value or more is provided, and the left and right torque distribution control means is configured to determine whether the abnormality is determined by the abnormality determining means. The right and left wheel speeds deviate from the target wheel speeds in order to execute the abnormal time corresponding torque distribution control (steps S5 to S15) for adjusting the torque distribution to the left and right wheels so that the actual wheel speeds of the left and right wheels are returned to appropriate values. When the motor or brake system is malfunctioning, it is possible to ensure straight running stability and cornering stability.

  (2) The abnormality determining means (step S2) obtains a wheel speed gap between each motor rotation number that drives the left and right wheels and a command value for each motor that drives the left and right wheels for each of the left and right wheels, and the wheel speed gap. Since the abnormality is determined for each of the left and right wheels when the value is equal to or greater than the specified value, one wheel abnormality and both wheel abnormality of the left and right wheels are accurately detected by easily detecting the wheel speed gap using the motor speed and the motor command value. Can be judged well.

  (3) The left and right torque distribution control means offsets the torque distribution value to the normal wheel side when the abnormality determination means determines that only one of the left and right wheels is abnormal and an overspeed abnormality. Or the output of the motor that drives the abnormal wheel is limited (step S7 → step S8, or step S10 → step S11). By adjusting the torque distribution to maintain the straight running performance, it is possible to ensure straight traveling performance and turning traveling performance.

  (4) The left and right torque distribution control means offsets the torque distribution value to the abnormal wheel side when the abnormality determination means determines that only one of the left and right wheels is abnormal and underrotation is abnormal. To increase the output of the motor that drives the abnormal wheel or to limit the output of the motor that drives the normal wheel (step S7 → step S9 or step S10 → step S12). In the case of an under-rotation abnormality of only one wheel, straight traveling performance and turning traveling performance can be ensured by adjusting torque distribution that maintains the four-wheel drive state.

  (5) When the left and right torque distribution control means determines that both of the left and right wheels are abnormal and can be corrected by the abnormality determination means, the torque distribution value is offset or the motor output is limited. Since correction is performed (step S13 → step S15), even if both the left and right wheels are abnormal, if the degree of abnormality is low, straight traveling performance and turning traveling performance can be improved by adjusting torque distribution to maintain the four-wheel drive state. Can be secured.

  (6) A turning degree detecting means (steering angle sensor 404) for detecting the turning degree is provided, and the left and right torque distribution control means goes straight when offsetting the torque distribution value or limiting the motor output based on the abnormality determination. Since the correction coefficient is set to 1 during driving and the turning correction (Fig. 5) is performed so that the correction coefficient increases as the turning degree is smaller radius turning, even if an abnormality occurs in the left and right wheel systems, straight driving performance is ensured. The influence on the turning traveling performance can be appropriately eliminated.

  (7) The left and right torque distribution control means prohibits output and regeneration to both motors when the abnormality determination means determines that both the left and right wheels are abnormal and cannot be corrected (step S13). → Step S14) Therefore, it is possible to prevent a decrease in running stability due to continuing power running / regeneration by both motors even though both the left and right wheels are abnormal and cannot be corrected.

  (8) Since the left and right torque distribution control means has a torque adjustment result storage unit (step S16) that stores a torque adjustment result at the time of abnormality determination and is applied at the next turn, it does not change with the passage of time. With respect to the occurrence of a steady abnormality, it is possible to execute an easy and stable abnormality handling torque distribution control.

  (9) The vehicle includes an engine 305 and a first motor 303 that drive one of the front and rear wheels, and a second motor that independently drives the left and right wheels of the other auxiliary driving wheel of the front and rear wheels. 308 and a third motor 309, a hybrid four-wheel drive vehicle, and the left and right torque distribution control means, when the wheel speed gap is determined to be normal with less than a specified value, so as to achieve neutral steering, In order to control the outputs of the second motor 308 and the third motor 309, the right and left rear wheel torque distribution optimization control can be executed by the high-response motor output torque, effectively ensuring driving and steering stability. In addition, both the left and right rear wheels become uncorrectable abnormalities, and even if rear output / regeneration is prohibited, it is possible to ensure running stability of straight travel and turning by two-wheel drive using only the main drive wheels.

  The vehicle torque distribution control device according to the present invention has been described based on the first embodiment. However, the specific configuration is not limited to the first embodiment, and the claims relate to each claim. Design changes and additions are allowed without departing from the scope of the invention.

  In the first embodiment, an example of performing abnormality detection by performing wheel speed gap detection using the motor rotational speed and motor command value of the left and right rear wheels has been shown, but for example, a wheel speed sensor is set for each of the left and right rear wheels, An abnormality may be determined based on the difference between the actual wheel speed value from the wheel speed sensor and the target wheel speed value obtained from the vehicle body speed in consideration of the difference between the inner and outer wheel speeds depending on the degree of straight travel or turning.

  In the first embodiment, an example in which any one of torque distribution value offset setting, motor torque limit, and motor torque increase is selected as the torque distribution control in response to an abnormality has been shown, but two or three are used in combination. Then, it is possible to perform the torque distribution control corresponding to the abnormality.

  In the first embodiment, an example has been shown in which the torque distribution offset amount and the motor torque limit value in the torque distribution control in response to an abnormality are set based on straight traveling, and this is made to correspond to turning by turning correction. A torque distribution offset amount and a motor torque limit value may be set without performing turning correction by a map including a degree, an arithmetic expression, or the like.

  In the first embodiment, the torque distribution control device for the hybrid four-wheel drive vehicle using the front wheel drive base and the rear wheel two motors is shown. However, the present invention can also be applied to a hybrid four wheel drive vehicle using the rear wheel drive base and the front wheel two motors. . Further, the present invention is not limited to a hybrid vehicle in which both an engine and a motor are mounted, and can be applied to an electric vehicle or a fuel cell vehicle having two front wheel motors, two rear wheel motors or a four wheel independent motor. In short, it is applicable to any vehicle having left and right torque distribution control means for controlling torque distribution to the left and right wheels in accordance with torque output commands to both motors, with at least one of the left and right wheels being driven by two motors. Is possible.

1 is an overall system diagram showing a hybrid four-wheel drive vehicle to which a torque distribution control device of Embodiment 1 is applied. 6 is a flowchart illustrating a flow of rear wheel left and right torque distribution control processing executed by the CPU of the first embodiment. It is a figure which shows an example of the rear motor output torque offset setting map used by the left-right torque distribution control of Example 1. FIG. It is a figure which shows an example of the rear motor output torque limitation map used by the left-right torque distribution control of Example 1. FIG. It is a figure which shows an example of the torque limitation according to the turning radius used by the left-right torque distribution control of Example 1, and an offset setting correction map.

Explanation of symbols

101 CPU
102 Auxiliary battery
301 Heavy battery
302 FR inverter
303 First motor (first motor)
304 generator
305 engine
306 Power split mechanism
307 Inverter for RR
308 Second motor (second motor)
309 Third motor (third motor)
401 Accelerator sensor
402 Brake sensor
403 DC / DC converter
404 Rudder angle sensor (turning degree detection means)
405 GPS
406 Wheel speed sensor

Claims (9)

In a vehicle provided with left and right torque distribution control means for controlling torque distribution to the left and right wheels by torque output commands to both motors, wherein at least one of the left and right wheels is driven by two motors.
An abnormality determining means is provided for determining an abnormality when the difference between the actual wheel speed of the left and right wheels and the target wheel speed is a specified value or more,
The left and right torque distribution control means executes an abnormal time corresponding torque distribution control that adjusts the torque distribution to the left and right wheels so that the actual wheel speed of the left and right wheels is returned to an appropriate value at the time of abnormality determination by the abnormality determination means. A vehicle torque distribution control device. In the vehicle torque distribution control device according to claim 1,
The abnormality determination means obtains a wheel speed gap for each of the left and right wheels between a rotation speed of each motor for driving the left and right wheels and a command value for each motor for driving the left and right wheels, and the wheel speed gap is not less than a specified value. A vehicle torque distribution control device characterized by determining an abnormality for each of the left and right wheels. In the vehicle torque distribution control device according to claim 2,
The left and right torque distribution control means offsets the torque distribution value to the normal wheel side when the abnormality determination means determines that only one of the left and right wheels is abnormal and an overspeed abnormality, or A torque distribution control device for a vehicle, which limits an output of a motor that drives an abnormal wheel. In the vehicle torque distribution control device according to claim 2,
The left and right torque distribution control means offsets the torque distribution value to the abnormal wheel side when the abnormality determination means determines that only one of the left and right wheels is abnormal and is under-rotation abnormality, or A torque distribution control device for a vehicle, characterized by increasing an output of a motor for driving an abnormal wheel or limiting an output of a motor for driving a normal wheel. In the torque distribution control device for a vehicle according to any one of claims 1 to 4,
The left and right torque distribution control means performs correction by offsetting the torque distribution value or limiting the output of the motor when the abnormality determination means determines that both the left and right wheels are abnormal and can be corrected. A torque distribution control device for a vehicle. In the torque distribution control device for a vehicle according to any one of claims 3 to 5,
A turning degree detecting means for detecting the turning degree is provided,
When the torque distribution value is offset or the motor output is limited based on the abnormality determination, the left / right torque distribution control means sets the correction coefficient to 1 when traveling straight and increases the correction coefficient as the turning degree is smaller radius turning. A vehicle torque distribution control device characterized in that a turning correspondence correction is performed. The torque distribution control device for a vehicle according to any one of claims 1 to 6,
The left and right torque distribution control means prohibits output and regeneration to both motors when the abnormality determination means determines that both the right and left wheels are abnormal and cannot be corrected. Torque distribution control device. The torque distribution control device for a vehicle according to any one of claims 1 to 7,
The left and right torque distribution control means has a torque adjustment result storage unit that stores a torque adjustment result when an abnormality is determined and is applied at the next turn. The torque distribution control device for a vehicle according to any one of claims 1 to 8,
The vehicle includes an engine and a first motor that drive one of the front and rear wheels, and a second motor and a third motor that independently drive the left and right wheels of the other auxiliary driving wheel of the front and rear wheels, respectively. Is a hybrid four-wheel drive vehicle equipped with
The left and right torque distribution control means controls the outputs of the second motor and the third motor so as to realize neutral steer when it is judged normal by the abnormality judgment means. Distribution controller.

Images