JP2015220912A - Vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle control device capable of suppressing vibration of a vehicle in to and fro direction which is caused by change in state of a road surface.SOLUTION: When one of a front wheel 6 and a rear wheel 10 comes in or out of a slope, output torques of motors 4, 7 for front wheel driving and rear wheel driving are corrected based on a ratio between a rotational speed of the front wheel and a rotational speed of the rear wheel.

Description

  The present invention relates to a vehicle control device for a vehicle using a motor as a power source.

  A vehicle including a motor as a power source, such as a hybrid vehicle or an electric vehicle, controls the driving torque of the motor in accordance with an accelerator operation or a running situation (for example, Patent Documents 1 and 2).

Japanese Patent No. 5109101 Japanese Patent No. 5348328

  The condition of the road surface on which the vehicle travels varies from flat to slope (uphill or downhill) and from slope to flat. This change in the road surface appears as vibration.

  The vibration includes a so-called longitudinal vibration in a direction along the traveling direction of the vehicle, in addition to a so-called vertical vibration in a direction orthogonal to the traveling direction of the vehicle. Of these, vertical vibrations are absorbed to some extent by vehicle parts such as suspensions, but the vibrations in the front-rear direction may be transmitted to the occupant's body with little absorption and may cause discomfort to the occupant.

  An object of the present invention is to provide a vehicle control device capable of suppressing vibrations in the front-rear direction of a vehicle due to a change in road surface conditions.

  According to a first aspect of the present invention, there is provided a vehicle control apparatus comprising: a first motor that drives front wheels of a vehicle; a second motor that drives rear wheels of the vehicle; and a control unit that controls output torque of these motors. Prepare. The control means corrects the output torque of each motor based on a comparison between the rotational speed of the front wheel and the rotational speed of the rear wheel when any one of the front wheel and the rear wheel enters or advances from the slope. To do.

  The vehicle control device of the invention according to claim 2 limits the control means of the invention according to claim 1. When the difference between the rotational speed of the front wheel and the rotational speed of the rear wheel is equal to or greater than a predetermined value, the control means corrects the output torque of the motor corresponding to the wheel having the larger rotational speed acceleration among the motors. To do.

  The vehicle control device of the invention according to claim 3 limits the control means of the invention according to claim 2. A control means determines the increase / decrease direction of the correction | amendment of the output torque of the motor corresponding to a wheel with the larger acceleration of rotational speed among the said each motor according to the positive / negative of the acceleration of the rotational speed.

  The vehicle control device of the invention according to claim 4 limits the control means of the invention according to claim 3. The control means determines the absolute value of the correction amount of the output torque of the motor corresponding to the wheel having the larger rotational speed acceleration among the motors according to the ratio between the rotational speeds.

  The vehicle control device of the invention according to claim 5 limits the control means of the invention according to claim 3. A control means determines the absolute value of the correction amount of the output torque of the motor corresponding to the wheel with the larger rotational speed acceleration among the motors according to the difference between the rotational speeds.

  According to the present invention, it is possible to suppress the vibration in the front-rear direction of the vehicle due to the change in the road surface condition. This improves the ride comfort of the vehicle.

The block diagram which shows the structure of one Embodiment of this invention. The figure which shows the relationship between the vehicle speed and motor output torque which concern on the same embodiment as an accelerator opening. The flowchart which shows the control of the same embodiment. The figure which shows a mode that the front wheel of the vehicle in connection with the embodiment enters the uphill (uphill slope) from the flat ground. 5 is a time chart showing changes in front wheel rotation speed, rear wheel rotation speed, rotation speed ratio, and output torque in the traveling state of FIG. 4. The figure which shows the relationship between the front-wheel moving distance in the driving | running | working state of FIG. 4, a rear-wheel moving distance, the wheel base of a vehicle, and the inclination angle of an uphill. The figure which shows the relationship between the rear-wheel movement distance in the driving | running | working state of FIG. The figure which shows a mode that the front wheel of the vehicle in connection with the embodiment advances to a flat ground from the downhill (downhill slope). The figure which shows a mode that the rear-wheel of the vehicle in connection with the embodiment approachs into a recessed part. The time chart which shows the change of the front-wheel rotational speed in the driving | running | working state of FIG. 9, a rear-wheel rotational speed, a rotational speed ratio, and an output torque. The figure which shows a mode that the front wheel of the vehicle in connection with the embodiment advances to a flat ground from the uphill (uphill slope). The time chart which shows the change of the front-wheel rotational speed in the driving | running | working state of FIG. 11, a rear-wheel rotational speed, a rotational speed ratio, and an output torque. The figure which shows a mode that the front wheel of the vehicle in connection with the embodiment enters a downhill (downhill) from a flat ground. The figure which shows a mode that the rear-wheel of the vehicle in connection with the embodiment approachs a convex part. The time chart which shows the change of the front-wheel rotational speed in the driving | running | working state of FIG. 14, a rear-wheel rotational speed, a rotational speed ratio, and an output torque.

Hereinafter, an embodiment of the present invention will be described.
As shown in FIG. 1, for example, an engine 2 is mounted on a front portion of a vehicle 1 that is a hybrid vehicle or the like, and an output shaft of the engine 2 is connected to a power transmission mechanism 3. The output shaft of the front wheel drive motor 4 is connected to the power transmission mechanism 3. The power transmission mechanism 3 transmits the driving torque (output torque) Te of the engine 2 or the driving torque (output torque) Tf of the motor 4 to the front axle 5. Front wheels 6 and 6 are attached to both ends of the front axle 5.

  A rear wheel driving motor 7 is mounted on the rear portion of the vehicle 1, and an output shaft of the motor 7 is transmitted to the power transmission mechanism 8. The power transmission mechanism 8 transmits the drive torque (output torque) Tr of the motor 7 to the rear axle 9. Rear wheels 10 and 10 are attached to both ends of the rear axle 9.

  A motor generator 11 for power generation is attached to the power transmission mechanism 8. The motor generator 11 operates by receiving power from the engine 2 or the front axle 5 and outputs an AC voltage. This output voltage is converted into a DC voltage by the converter 12, and the DC voltage is charged to the battery power supply 20 mounted on the vehicle 1 as regenerative energy.

  A rotational speed sensor 13 is arranged for the front axle 5. A rotational speed sensor 14 is arranged for the rear axle 9. The rotational speed sensor 13 detects the rotational speed of the front axle 5 as the rotational speed Vf of the front wheel 6. The rotational speed sensor 14 detects the rotational speed of the rear axle 9 as the rotational speed Vr of the rear wheel 10. Hereinafter, the rotation speeds Vf and Vr are referred to as front wheel rotation speed Vf and rear wheel rotation speed Vr.

  On the other hand, an ECU (Electric-Control-Unit) 30 serving as a control unit (control means) is connected to rotational speed sensors 13 and 14, inverters 21 and 22, accelerator opening sensor 31, brake sensor 32, vehicle speed sensor 33, and shift position sensor. 34 is connected.

  The inverter 21 converts the DC voltage of the battery power supply 20 into an AC voltage having a predetermined frequency and a predetermined level by switching according to a command from the ECU 30 and outputs the AC voltage. This output is applied to the winding of the motor 4 for driving the front wheels. By this application, the motor 4 operates. The rotation speed of the motor 4 changes according to the output frequency of the inverter 21. The output torque Tf of the motor 4 is determined according to the output voltage level of the inverter 21.

  The inverter 22 converts the DC voltage of the battery power supply 20 into an AC voltage having a predetermined frequency and a predetermined level by switching according to a command from the ECU 30 and outputs the AC voltage. This output is applied to the winding of the motor 7 for driving the rear wheels. By this application, the motor 7 operates. The rotational speed of the motor 7 changes according to the output frequency of the inverter 22. The output torque Tr of the motor 7 is determined according to the output voltage level of the inverter 22.

  The accelerator opening sensor 31 detects the opening Q of the accelerator pedal of the vehicle 1. The brake sensor 32 detects the amount of depression of the brake pedal of the vehicle 1. The vehicle speed sensor 33 detects the traveling speed (vehicle speed H) of the vehicle 1. The shift position sensor 34 detects the shift position (parking range P, reverse mode range R, neutral range N, drive mode range D, etc.) of the shift lever of the vehicle 1.

The ECU 30 has the following means (1) to (7) as main functions.
(1) By referring to the data for setting the target driving torque Tt stored in the internal memory based on the detected opening of the accelerator opening sensor 31 and the detected vehicle speed of the vehicle speed sensor 33, the target driving torque (in the vehicle Setting means for setting required torque (Tt).

  (2) Engine control means for controlling the engine 1 so that the output torque Te of the engine 2 becomes the set target drive torque (required torque) Tt when the vehicle 1 is driven by the output of the engine 2.

  (3) When the vehicle 1 is driven by the outputs of the motors 4 and 7, the motors that control the outputs of the inverters 21 and 22 so that the output torques Tf and Tr of the motors 4 and 7 become the target drive torque (required torque) Tt. Control means.

  (4) When the vehicle 1 travels with the output of the motors 4 and 7, the difference ΔV (= | Vf−) between the front wheel rotational speed Vf detected by the rotational speed sensor 13 and the rear wheel rotational speed Vr detected by the rotational speed sensor 14. Speed difference detecting means for detecting Vr |).

  (5) Acceleration detecting means for detecting the acceleration dVf of the front wheel rotational speed Vf and the acceleration dVr of the rear wheel rotational speed Vr. The acceleration of the rotation speed is a change amount of the rotation speed that changes in a unit time (1 second).

  (6) When the detected rotational speed difference ΔV is greater than or equal to a predetermined value ΔVs (ΔV ≧ ΔVs), the gradient that determines that the wheel with the higher rotational speed acceleration enters or exits the gradient existing in the vehicle longitudinal direction Judgment means. Here, the fact that the rotational speed acceleration is large does not mean that the absolute value of the rotational speed acceleration is large.

  (7) When the gradient determination means determines entry into the gradient or advancement from the gradient, the wheel having the higher rotational speed acceleration of the motors 4 and 7 (the wheel that has entered the gradient or the wheel that has advanced from the gradient) The torque correction means for correcting the output torque of the motor corresponding to) based on the comparison between the front wheel rotational speed Vf and the rear wheel rotational speed Vr.

  The relationship between the vehicle speed H controlled by the motor control means (3) and the output torques Tf, Tr of the motors 4, 7 is illustrated with the accelerator opening Q1, Q2, Q3 (Q1 <Q2 <Q3) as a parameter. It is shown in 2. Although three stages of accelerator opening Q1, Q2, Q3 are shown, there are actually multiple stages of accelerator opening Q.

  Specifically, the gradient determining means (6) described above is such that the rotational speed difference ΔV is equal to or greater than a predetermined value ΔVs (ΔV ≧ ΔVs), the positive / negative of the acceleration dVf of the front wheel rotational speed Vf, and the acceleration of the rear wheel rotational speed Vr. When the sign of dVr is the same [(dVf> 0, dVr> 0) or (dVf <0, dVr <0)], the wheel with the higher rotational speed acceleration enters or leaves the gradient in the vehicle longitudinal direction. It is determined that the company has advanced. Even if the rotational speed difference ΔV is equal to or greater than the predetermined value ΔVs, if the sign of the acceleration dVf of the front wheel rotational speed Vf is different from the sign of the acceleration dVr of the rear wheel rotational speed Vr, [(dVf> 0, dVr <0 ) Or (dVf <0, dVr> 0)], it is determined that idling so-called slip has occurred in the wheel. For example, when the front wheel 6 enters a road surface with a weak grip force and the front wheel 6 slips, the driving force of the front wheel 6 decreases, and the rotational speed Vr of the rear wheel 10 decreases accordingly. At this time, the acceleration dVf of the front wheel rotational speed Vf is positive, and the acceleration dVr of the rear wheel rotational speed Vr is negative. This is determined to be idle.

  Specifically, the torque correction means of (6) described above is such that the output torque of the motor corresponding to the wheel having the higher rotational speed acceleration when the gradient determination means determines entry into or out of the gradient. Is corrected by an amount proportional to the acceleration at the same rotational speed of the wheel having the smaller rotational speed acceleration. The increase / decrease direction of this correction is determined according to the sign of the acceleration of the rotational speed.

Next, control when the vehicle 1 travels with the output of the motors 4 and 7 will be described with reference to the flowchart of FIG.
The ECU 30 determines whether the rotational speed difference ΔV (= | Vf−Vr |) is equal to or greater than a predetermined value ΔVs (step S1).

  When the difference ΔV between the front wheel rotation speed Vf and the rear wheel rotation speed Vr is equal to or greater than the predetermined value ΔVs (YES in step S1), the ECU 30 determines whether the acceleration dVf of the front wheel rotation speed Vf is positive or negative and the acceleration dVr of the rear wheel rotation speed Vr. It is determined whether the sign is the same (step S2).

  When the sign of the acceleration dVf of the front wheel rotational speed Vf and the sign of the acceleration dVr of the rear wheel rotational speed Vr are the same (YES in step S2), the ECU 30 determines the gradient in which the wheel having the larger rotational speed acceleration exists in the vehicle longitudinal direction. If it is determined that the vehicle has entered the vehicle or moved from the slope, whether the brake of the vehicle 1 is off, whether the shift position of the shift lever is in the drive mode, and the accelerator opening Q is greater than “0”. Is determined from the detection results of the brake sensor 32, the shift position sensor 34, and the accelerator opening sensor 31 (steps S3, S4, S5).

  When the brake of the vehicle 1 is off (YES in step S3), the shift position of the shift lever is in the drive mode (YES in step S4), and the accelerator opening Q is larger than “0” (YES in step S5), the ECU 30 The processing from the next step S5 is executed under the determination that the control conditions for suppression are met.

[Entry from flat ground to climbing slope (climbing slope)]
FIG. 4 shows a state in which the front wheel 6 of the vehicle 1 traveling forward on the flat land Ea enters the uphill (uphill slope) Eb. FIG. 5 shows changes in the front wheel rotational speed Vf, the rear wheel rotational speed Vr, the rotational speed ratio K (= “Vf / Vr), the output torque Tf of the motor 4 and the output torque Tr of the motor 7 in this traveling state. The solid line in FIG. 5 shows the change when the ECU 30 has no torque correction, and the broken line shows the change when the ECU 30 has torque correction.

  When the front wheel 6 enters the ascending slope Eb from the flat land Ea, the front wheel rotational speed Vf decreases and the rear wheel rotational speed Vr also decreases. At this time, the front wheel rotation speed Vf is higher than the rear wheel rotation speed Vr (the rear wheel rotation speed Vr is greatly reduced). When the rear wheel 10 enters the same uphill Eb while the front wheel 6 is on the uphill Eb, the front wheel rotation speed Vf and the rear wheel rotation speed Vr have the same value.

  The rotation speed ratio K (= Vf / Vr) increases to a value exceeding “1” when the front wheel 6 enters the uphill slope Eb from the flat land Ea. Subsequently, the rotational speed ratio K gradually decreases to a value less than “1”, and returns to “1” when the rear wheel 10 enters the same uphill Eb while the front wheel 6 is on the uphill Eb.

In the traveling state of FIG. 4, the relationship between the front wheel movement distance y and the rear wheel movement distance x after the front wheel 6 enters the uphill Eb, the wheel base L of the vehicle 1, and the inclination angle θ of the uphill Eb is shown. It is shown in FIG.
By the second cosine theorem of the triangle,

Convert this into an expression of y

  It becomes.

  FIG. 7 shows the relationship between the rear wheel movement distance x and the front / rear wheel movement distance ratio “y / x” when the wheel base L of the vehicle 1 is 2,670 mm and the inclination angle θ of the uphill Eb is 170 degrees.

  The decrease in the front wheel rotational speed Vf and the rear wheel rotational speed Vr that occur when the front wheel 6 enters the ascending slope Eb from the flat ground Ea appears as vibration in the front-rear direction of the vehicle body 1, and the vibration in the front-rear direction is caused by the passenger It is transmitted to the body as a shock.

  Therefore, the ECU 30 reduces the front wheel rotational speed Vf and the rear wheel rotational speed Vr, the rotational speed ratio K increases to more than “1”, and the acceleration dVf of the front wheel rotational speed Vf is the acceleration dVr of the rear wheel rotational speed Vr. When it is larger (YES in step S6), the output torque Tf of the motor 4 corresponding to the front wheel 6 with the larger rotational speed acceleration is corrected in the increasing direction as indicated by a broken line in FIG. 5 (step S7). The absolute value of this correction amount is proportional to the smaller acceleration dVr.

  In this way, by correcting the output torque Tf of the motor 4 on the front wheel 6 side in the increasing direction, it is possible to suppress a decrease in the front wheel rotation speed Vf and the rear wheel rotation speed Vr, as indicated by a broken line in FIG. . Thereby, the vibration in the front-rear direction of the vehicle body 1 when the front wheel 6 enters the ascending slope Eb from the flat ground Ea can be suppressed, and the ride comfort of the passenger is improved.

  In this case, the output torque Tf of the motor 4 on the front wheel 6 side is corrected, but the output torque Tr on the rear wheel 10 side may be corrected. Alternatively, both output torques Tf and Tr may be corrected.

  However, the rotational speed change caused by the output torque correction is transmitted as a shock to the body of the passenger of the vehicle 1. In particular, the passenger is more likely to feel as a shock the change in the rear wheel rotation speed Vr with the smaller rotation speed acceleration than the change in the front wheel rotation speed Vf with the larger rotation speed acceleration.

  Considering this point, the correction amount of the output torque is set to the acceleration dVr of the rear wheel rotational speed Vr in order to minimize the change in the rear wheel rotational speed Vr that is easy to feel as a shock (one with a smaller rotational speed acceleration). The output torque correction target is limited to the output torque Tf of the motor 4 on the side that is hard to feel as a shock (the one with the larger acceleration of the rotational speed). Thereby, the shock transmitted to a passenger can be reduced more effectively.

[Advance from downhill (downhill) to flat land]
FIG. 8 shows a state in which the front wheel 6 of the vehicle 1 enters the flat ground Ee from the downhill (downhill gradient) Ed.
In this case, changes in the front wheel rotation speed Vf, the rear wheel rotation speed Vr, the rotation speed ratio K, the output torque Tf, and the output torque Tr are substantially the same as the changes in FIG. 5 when the front wheel 6 enters the uphill slope Eb from the flat ground Ea. The same. In FIG. 5, “front wheel enters uphill” may be replaced with “front wheel enters uphill”, and “rear wheel enters uphill” may be replaced with “rear wheel uphill”.

  The decrease in the front wheel rotation speed Vf and the rear wheel rotation speed Vr that occurs when the front wheel 6 advances from the downhill Ed to the flat ground Ee appears as vibrations in the front-rear direction of the vehicle body 1. It is transmitted to the body as a shock.

  In order to alleviate this shock, the ECU 30 corrects the output torque Tf of the motor 4 corresponding to the front wheel 6 with the higher rotational speed acceleration in the increasing direction, as in the case of “approaching uphill from flat ground” ( Step S7). The absolute value of this correction amount is proportional to the smaller acceleration dVr.

  Thereby, the reduction | decrease of the front-wheel rotational speed Vf and the rear-wheel rotational speed Vr can be suppressed. As a result, the vibration in the front-rear direction of the vehicle body 1 when the front wheels 6 advance from the downhill Ed to the flat ground Ee can be suppressed, and the ride comfort of the passenger is improved.

[Entry into flat recess]
FIG. 9 shows a state in which the rear wheel 10 of the vehicle 1 traveling forward on the flat land Ea enters the downhill (downhill) Ha of the recess. FIG. 10 shows changes in the front wheel rotational speed Vf, the rear wheel rotational speed Vr, the rotational speed ratio K, the output torque Tf, and the output torque Tr in this traveling state. The solid line in FIG. 10 shows the change when the ECU 30 has no torque correction, and the broken line shows the change when the ECU 30 has torque correction.

  When the rear wheel 10 enters the downhill Ha of the recess while the front wheel 6 is on the flat ground Ea, the rear wheel rotation speed Vr increases and the front wheel rotation speed Vf increases. At this time, the rear wheel rotation speed Vr is higher than the front wheel rotation speed Vf (the rear wheel rotation speed Vr is greatly increased). When the rear wheel 10 advances from the downhill (gradient) Ha of the recess to the flat portion Hb of the same recess, the front wheel rotation speed Vf and the rear wheel rotation speed Vr have the same value.

  The rotational speed ratio K (= Vf / Vr) drops to a value less than “1” when the rear wheel 10 enters the downhill Ha of the recess. Subsequently, the rotation speed ratio K gradually increases, and returns to “1” when the rear wheel 10 advances into the flat portion Hb of the recess.

  The increase in the front wheel rotational speed Vf and the rear wheel rotational speed Vr that occur when the rear wheel 10 enters the downhill Ha of the recess appears as vibration in the front-rear direction of the vehicle body 1, and the vibration in the front-rear direction is caused by the passenger's vibration. It is transmitted to the body as a shock.

  Therefore, the ECU 30 increases the front wheel rotational speed Vf and the rear wheel rotational speed Vr, the rotational speed ratio K decreases below “1”, and the acceleration dVr of the rear wheel rotational speed Vr becomes the acceleration dVf of the front wheel rotational speed Vf. When it is larger (NO in step S6, YES in step S8), the output torque Tr of the motor 7 corresponding to the rear wheel 10 with the larger acceleration of the rotational speed is corrected in a decreasing direction as indicated by a broken line in FIG. Step S9). The absolute value of this correction amount is proportional to the smaller acceleration dVf.

  In this way, by correcting the output torque Tr of the motor 7 on the rear wheel 10 side in the decreasing direction, it is possible to suppress increases in the front wheel rotation speed Vf and the rear wheel rotation speed Vr, as indicated by broken lines in FIG. it can. Thereby, the vibration in the front-rear direction of the vehicle body 1 when the rear wheel 10 enters the downhill Ha of the recess can be suppressed, and the ride comfort of the passenger is improved.

  In this case, the output torque Tr of the motor 7 on the rear wheel 10 side is corrected, but the output torque Tf of the motor 4 on the front wheel 6 side may be corrected. Alternatively, both output torques Tf and Tr may be corrected.

  However, the rotational speed change caused by the output torque correction is transmitted as a shock to the body of the passenger of the vehicle 1. In particular, the passenger is more likely to feel as a shock the change in the front wheel rotation speed Vf with the smaller rotation speed acceleration than the change in the rear wheel rotation speed Vr with the larger rotation speed acceleration.

  In consideration of this point, in order to minimize the change in the front wheel rotation speed Vf that is easily felt as a shock, the output torque correction amount is set to a value proportional to the acceleration dVf of the front wheel rotation speed Vf, and the output The target of torque correction is limited to the output torque Tr of the motor 7 that is hard to feel as a shock. Thereby, the shock transmitted to a passenger can be reduced more effectively.

[Advance from climbing slope (climbing slope) to flat ground]
FIG. 11 shows a state in which the front wheel 6 of the vehicle 1 advances from the uphill (uphill slope) Eb to the flat land Ec. FIG. 12 shows changes in the front wheel rotational speed Vf, the rear wheel rotational speed Vr, the rotational speed ratio K, the output torque Tf, and the output torque Tr in this traveling state. The solid line in FIG. 12 shows the change when the ECU 30 has no torque correction, and the broken line shows the change when the ECU 30 has torque correction.

  When the front wheel 6 advances from the uphill Eb to the flat land Ec, the front wheel rotational speed Vf increases and the rear wheel rotational speed Vr increases. At this time, the front wheel rotation speed Vf is higher than the rear wheel rotation speed Vr (the front wheel rotation speed Vf is greatly increased). When the rear wheel 10 advances to the same flat ground Ec with the front wheel 6 existing on the flat ground Ec, the front wheel rotational speed Vf and the rear wheel rotational speed Vr have the same value.

  The rotational speed ratio K (= Vf / Vr) increases to a value exceeding “1” when the front wheel 6 advances from the uphill Eb to the flat land Ec. Subsequently, the rotational speed ratio K gradually decreases to a value of less than “1”, and returns to “1” when the rear wheel 10 advances to the same flat ground Ec while the front wheel 6 is on the flat ground Ec.

  The increase in the front wheel rotation speed Vf and the rear wheel rotation speed Vr that occurs when the front wheel 6 advances from the ascending slope Eb to the flat ground Ec appears as vibration in the front-rear direction of the vehicle body 1, and the vibration in the front-rear direction is It is transmitted to the body as a shock.

  Therefore, the ECU 30 increases the front wheel rotational speed Vf and the rear wheel rotational speed Vr, the rotational speed ratio K increases to “1”, and the acceleration dVf of the front wheel rotational speed Vf is the acceleration dVr of the rear wheel rotational speed Vr. When it is larger (NO in step S6, NO in step S8, YES in step S10), the output torque Tf of the motor 4 corresponding to the front wheel 6 with the higher rotational speed acceleration is decreasing as shown by the broken line in FIG. (Step S11). The absolute value of this correction amount is proportional to the smaller acceleration dVr.

  As described above, by correcting the output torque Tf of the motor 4 corresponding to the front wheel 6 in the decreasing direction, it is possible to suppress an increase in the front wheel rotational speed Vf and the rear wheel rotational speed Vr, as indicated by a broken line in FIG. it can. Thereby, the vibration in the front-rear direction of the vehicle body 1 when the front wheels 6 advance from the uphill Eb to the flat ground Ec can be suppressed, and the ride comfort of the passenger is improved.

  In this case, the output torque Tf of the motor 4 on the front wheel 6 side is corrected, but the output torque Tr of the motor 7 on the rear wheel 10 side may be corrected. Alternatively, both output torques Tf and Tr may be corrected.

  However, the rotational speed change caused by the output torque correction is transmitted as a shock to the body of the passenger of the vehicle 1. In particular, the passenger is more likely to feel as a shock the change in the rear wheel rotation speed Vr with the smaller rotation speed acceleration than the change in the front wheel rotation speed Vf with the larger rotation speed acceleration.

  Considering this point, in order to minimize the change in the rear wheel rotational speed Vr that is easily felt as a shock, the correction amount of the output torque is set to a value proportional to the acceleration dVr of the rear wheel rotational speed Vr. The target of the output torque correction is limited to the output torque Tf of the motor 4 that is hard to feel as a shock. Thereby, the shock transmitted to a passenger can be reduced more effectively.

[Entry from flat ground to downhill (downhill)]
FIG. 13 shows how the front wheel 6 of the vehicle 1 enters the downhill (downhill) Ed from the flat ground Ec.
Changes in the front wheel rotational speed Vf, the rear wheel rotational speed Vr, the rotational speed ratio K, the output torque Tf, and the output torque Tr in this case are substantially the same as the changes in FIG. 12 when the front wheel 6 advances from the uphill Eb to the flat ground Ec. The same. In FIG. 12, “front wheel advances into flat ground” may be replaced with “front wheel enters downhill”, and “rear wheel advances into flat ground” may be replaced with “rear wheel enters downhill”.

  The decrease in the front wheel rotational speed Vf and the rear wheel rotational speed Vr that occurs when the front wheel 6 enters the downhill Ed from the flat ground Ec appears as vibration in the front-rear direction of the vehicle body 1. It is transmitted to the body as a shock.

  In order to reduce this shock, the ECU 30 corrects the output torque Tf of the motor 4 corresponding to the front wheel 6 with the higher rotational speed acceleration in the decreasing direction, as in the case of “advancing from the uphill to the flat ground” ( Step S11). The absolute value of this correction amount is proportional to the smaller acceleration dVr.

  Thereby, an increase in the front wheel rotation speed Vf and the rear wheel rotation speed Vr can be suppressed. As a result, the vibration in the front-rear direction of the vehicle body 1 when the front wheels 6 advance from the flat ground Ec to the downhill Ed can be suppressed, and the ride comfort of the passenger is improved.

[Entry to the convex part of the flat ground]
FIG. 14 shows a state in which the rear wheel 10 of the vehicle 1 traveling forward on the flat land Ea enters an uphill slope (climbing slope) Hc. FIG. 15 shows changes in the front wheel rotational speed Vf, the rear wheel rotational speed Vr, the rotational speed ratio K, the output torque Tf, and the output torque Tr in this traveling state. The solid line in FIG. 15 shows the change when the ECU 30 has no torque correction, and the broken line shows the change when the ECU 30 has torque correction.

  When the rear wheel 10 enters the uphill slope Hc with the front wheel 6 on the flat ground Ea, the rear wheel rotational speed Vr decreases and the front wheel rotational speed Vf decreases. At this time, the rear wheel rotation speed Vr is higher than the front wheel rotation speed Vf (the front wheel rotation speed Vf is greatly reduced). When the rear wheel 10 advances from the uphill Hc of the convex portion to the flat portion Hd of the same convex portion, the front wheel rotational speed Vf and the rear wheel rotational speed Vr have the same value.

  The rotational speed ratio K (= Vf / Vr) drops to a value less than “1” when the rear wheel 10 enters the uphill slope Hc of the convex portion. Subsequently, the rotational speed ratio K gradually increases and returns to “1” when the rear wheel 10 advances to the flat portion Hd of the convex portion.

  The decrease in the front wheel rotational speed Vf and the rear wheel rotational speed Vr that occurs when the rear wheel 10 enters the convex uphill Hc appears as vibration in the front-rear direction of the vehicle body 1. It is transmitted as a shock to the body.

  Therefore, the ECU 30 reduces the front wheel rotational speed Vf and the rear wheel rotational speed Vr, the rotational speed ratio K decreases below “1”, and the acceleration dVr of the rear wheel rotational speed Vr becomes the acceleration dVf of the front wheel rotational speed Vf. When it is larger (NO in step S6, NO in step S8, NO in step S10, YES in step S12), the output torque Tr of the motor 7 corresponding to the rear wheel 10 having the larger acceleration of the rotational speed is indicated by a broken line in FIG. As shown by, correction is made in the increasing direction (step S13). The absolute value of this correction amount is proportional to the smaller acceleration dVf.

  Thus, by correcting the output torque Tr of the motor 7 on the rear wheel 10 side in the increasing direction, as shown by the broken line in FIG. 15, it is possible to suppress the decrease in the front wheel rotational speed Vf and the rear wheel rotational speed Vr. it can. Thereby, the vibration in the front-rear direction of the vehicle body 1 when the rear wheel 10 enters the ascending slope Hc of the convex portion can be suppressed, and the ride comfort of the passenger is improved.

  In this case, the output torque Tr of the motor 7 on the rear wheel 10 side is corrected, but the output torque Tf of the motor 4 on the front wheel 6 side may be corrected. Alternatively, both output torques Tf and Tr may be corrected.

  However, the rotational speed change caused by the output torque correction is transmitted as a shock to the body of the passenger of the vehicle 1. In particular, the passenger is more likely to feel as a shock the change in the front wheel rotation speed Vf with the smaller rotation speed acceleration than the change in the rear wheel rotation speed Vr with the larger rotation speed acceleration.

  In consideration of this point, in order to minimize the change in the front wheel rotation speed Vf that is easily felt as a shock, the output torque correction amount is set to a value proportional to the acceleration dVf of the front wheel rotation speed Vf and the output The target of torque correction is limited to the output torque Tr of the motor 7 that is hard to feel as a shock. Thereby, the shock transmitted to a passenger can be reduced more effectively.

[Modification]
The torque correction means in the above embodiment sets the output torque correction amount of the motor corresponding to the wheel with the larger rotational speed acceleration to a value corresponding to the rotational speed acceleration dV of the wheel with the smaller rotational speed acceleration. However, the value is not limited to the acceleration dV of the rotational speed, and may be set to a value corresponding to the ratio “Vf / Vr” of the rotational speeds Vf and Vr. Or you may set to the value according to difference (DELTA) V (= | Vf-Vr |) of both rotation speed Vf and Vr.

  Although the case where the vehicle 1 is a hybrid vehicle has been described as an example, the present invention can be similarly performed when the vehicle 1 is an electric vehicle.

  In addition, the said embodiment is shown as an example and is not intending limiting the range of invention. The novel embodiments and modifications can be implemented in various other forms, and various omissions, rewrites, and changes can be made without departing from the spirit of the invention. In these embodiments and modifications, the scope of the invention is included in the gist, and is included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Engine, 3 ... Power transmission mechanism, 4 ... Motor, 5 ... Front axle, 6 ... Front wheel, 7 ... Motor, 8 ... Power transmission mechanism, 9 ... Rear axle, 10 ... Rear wheel, 11 ... Motor Generator, 12 ... Converter, 13, 14 ... Rotational speed sensor, 20 ... Battery power supply, 21, 22 ... Inverter, 30 ... ECU (control means), 31 ... Accelerator opening sensor, 32 ... Brake sensor, 33 ... Vehicle speed sensor, 34 ... Shift position sensor

Claims (5)

A first motor that drives the front wheels of the vehicle;
A second motor for driving rear wheels of the vehicle;
Control means for controlling the output torque of each motor;
With
When either one of the front wheel and the rear wheel enters or advances from a gradient, the control means determines the output torque of each motor based on a comparison between the rotation speed of the front wheel and the rotation speed of the rear wheel. The vehicle control apparatus characterized by correcting. When the difference between the rotational speed of the front wheel and the rotational speed of the rear wheel is equal to or greater than a predetermined value, the control means outputs the output torque of the motor corresponding to the wheel having the larger rotational speed acceleration among the motors. It correct | amends. The vehicle control apparatus of Claim 1 characterized by the above-mentioned. The control means determines the increase / decrease direction of the correction of the output torque of the motor corresponding to the wheel having the larger rotational speed acceleration among the motors according to the sign of the rotational speed acceleration. The vehicle control device according to claim 2. The control means determines an absolute value of a correction amount of an output torque of a motor corresponding to a wheel having a larger rotational speed acceleration among the motors according to a ratio of both rotational speeds. The vehicle control device according to claim 3. The control means determines an absolute value of a correction amount of an output torque of a motor corresponding to a wheel having a larger rotational speed acceleration among the motors according to a difference between the rotational speeds. The vehicle control device according to claim 3.

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