JP4557157B2 - Electric vehicle control system - Google Patents

Description

  The present invention relates to a vehicle control device for an electric vehicle, and more particularly to a technique for suppressing pitching of a vehicle.

The posture of the vehicle body changes depending on the traveling state and the road surface state. For example, when acceleration or deceleration is performed, so-called pitching, which is a vertical change in the front-rear direction of the vehicle body, occurs, and when turning, so-called rolling, which is a vertical change in the left-right direction of the vehicle body, occurs. Further, pitching or rolling may occur due to unevenness of the road surface.
In order to suppress such a change in vehicle body posture, the vehicle is provided with a suspension device (suspension), a shock absorber (damper), and the like.

Although the ride comfort and handling stability of the vehicle are determined by the settings of these suspensions and dampers, it is difficult to achieve both ride comfort and handling stability.
Therefore, a technology has been developed to control the vehicle body posture by controlling the driving force of the vehicle to complement the functions of the suspension and the damper.
For example, when the front wheel part (front) of the vehicle body is raised, the moment in the direction of raising the front due to the reaction force from the road surface is reduced by reducing the output torque of the vehicle, and when the front is lowered, There is a technique for increasing the moment in the direction of raising the front due to the reaction force from the road surface applied to the drive wheels by increasing the output torque of the vehicle and suppressing the pitching of the vehicle (see Patent Document 1).
JP 62-12305 A

However, in the technique disclosed in Patent Document 1, since the overall output torque is reduced during acceleration in order to suppress the pitching of the vehicle body, the driving force necessary for acceleration cannot be obtained sufficiently, and the entire output torque during deceleration is not obtained. Since the output torque is increased, the braking force necessary for deceleration may not be obtained sufficiently, which is not preferable.
As described above, in Patent Document 1, the overall output torque is controlled and the reaction force from the road surface is increased or decreased to suppress the pitching of the vehicle, so that the running stability of the vehicle is impaired. There's a problem.

  Further, referring now to FIG. 5, a schematic diagram illustrating the anti-squat angle in a typical vehicle is shown. As shown in the figure, in a general vehicle configured to transmit a driving force generated from a motor or an internal combustion engine from a drive shaft 100 to a driving wheel 102, including the above-mentioned Patent Document 1, the mounting position of the lower arm 104 and the suspension A line L1 ′ drawn from an instantaneous rotation center O ′ determined by the mounting angle 106 to an action point B (center of the drive wheel 102 connected to the drive shaft 100) for transmitting force from the drive wheel 102 to the vehicle body, The angle βf with respect to the horizontal line L2 ′ from the action point B was relatively small.

The angle is an anti-squat angle that affects the control width of the anti-squat generated by the driving force with respect to the so-called squat phenomenon of the vehicle, which is the vertical displacement of the vehicle body. It becomes easy to obtain an effect.
However, it is difficult for a conventional vehicle to take a large anti-squat angle, and the effect of anti-squat is not obtained so much.

  The present invention has been made in order to solve the above-described problems, and the object of the present invention is to control the vehicle driving force while favorably suppressing the vehicle pitching while ensuring the running stability. Another object of the present invention is to provide a vehicle control device for an electric vehicle that can improve the ride comfort of the occupant.

In order to achieve the above-described object, in the vehicle control device for an electric vehicle according to claim 1, a traveling drive motor that is provided on each of the front wheel and the rear wheel of the vehicle and drives the wheel; Acceleration / deceleration detection means for detecting a deceleration state, pitching detection means for detecting vertical displacement of the vehicle in the longitudinal direction of the vehicle, and when the acceleration state of the vehicle is detected by the acceleration / deceleration detection means , the pitching detection means In accordance with the detected upward displacement of the front side of the vehicle body, the control for increasing the driving force of the front wheel by the travel drive motor, and the downward displacement of the rear side of the vehicle body detected by the pitching detection means And driving force control means for performing either or both of the control for increasing the driving force of the travel driving motor for the rear wheels .

As a result, during acceleration of the vehicle, control for increasing the driving force of the front wheels according to the upward displacement of the front side of the vehicle body and control for increasing the driving force of the rear wheels according to the downward displacement of the rear side of the vehicle body. Either or both are performed to suppress the vertical displacement .

In the vehicle control apparatus for an electric vehicle 請 Motomeko 2 is provided on each of the wheels of the front and rear wheels of the vehicle, a travel drive motor for driving the wheel acceleration and deceleration detection for detecting a deceleration state of the vehicle Means, a pitching detection means for detecting the vertical displacement of the vehicle in the longitudinal direction of the vehicle, and a downward direction on the vehicle front side detected by the pitching detection means when the deceleration state of the vehicle is detected by the acceleration / deceleration detection means Control for reducing the driving force of the driving motor for the front wheels according to the displacement of the front wheel, and the traveling of the rear wheels according to the upward displacement on the rear side of the vehicle body detected by the pitching detection means. Power control means for performing both or one of the controls for reducing the driving force by the driving motor is provided .

As a result, when the vehicle is decelerating, the control of reducing the driving force of the front wheels according to the downward displacement of the front side of the vehicle body and the control of reducing the driving force of the rear wheels according to the upward displacement of the rear side of the vehicle body. Do both or either.
The vehicle control apparatus for an electric vehicle according to claim 3 is characterized in that the driving force to be increased or decreased by the driving force control means is limited within a predetermined range.

Thus, the driving force used for pitching suppression is limited within a predetermined range.
5. The vehicle control apparatus for an electric vehicle according to claim 4 , further comprising acceleration / deceleration prediction means for predicting acceleration / deceleration of the vehicle, wherein the driving force control means detects an acceleration / deceleration change amount detected by the acceleration / deceleration prediction means. When is greater than or equal to a predetermined value, the driving force of the travel drive motor is controlled so that the degree of vertical change in the longitudinal direction caused by the acceleration / deceleration is attenuated.

  Thus, the degree of change in pitching during acceleration / deceleration of the vehicle body is attenuated by the driving force.

According to the vehicle control apparatus for an electric vehicle of claim 1 of the present invention using the above means, the electric vehicle of the in-wheel motor can obtain a wide control width of the anti-squat because the anti-squat angle is large. Further, by providing an in-wheel motor for each wheel, the driving force can be controlled independently for each wheel.
Accordingly, the vertical displacement can be sufficiently suppressed by controlling the driving force of either or both of the front wheels and the rear wheels in accordance with the vertical displacement of the front and rear of the vehicle body at the time of acceleration / deceleration of the vehicle. The ride comfort can be improved.

In particular, by controlling the driving force of the wheels, it is possible to suppress the pitching during acceleration by improving the force for lowering the vehicle body on the front side of the vehicle body and the force for raising the vehicle body on the rear side of the vehicle body.
According to the vehicle control device for an electric vehicle of the second aspect , by controlling the driving force of the wheels, the force for lowering the vehicle body on the front side of the vehicle body and the force for raising the vehicle body on the rear side of the vehicle body are reduced. , Pitching during deceleration can be suppressed.

According to the vehicle control apparatus for an electric vehicle of claim 3 , by limiting the driving force used for suppressing the pitching of the vehicle, the driving force necessary for the acceleration / deceleration of the vehicle can be ensured, and the running stability of the vehicle can be secured. Sex can be maintained.
According to the vehicle control apparatus for an electric vehicle of the fourth aspect , the same effect as that of a general damper can be obtained by controlling the driving force.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Referring to FIG. 1, there is shown a schematic configuration diagram of an electric vehicle equipped with a vehicle control device according to the present invention. With reference to FIG. 2, the anti-squat angle of an electric vehicle equipped with a vehicle control device according to the present invention is shown. A schematic diagram is shown.
As shown in FIG. 1, a vehicle 1 is a four-wheel drive electric vehicle in which each wheel 2 is provided with a drive motor 4 (running drive motor) independently.

Specifically, a right front drive motor 4FR is provided in the right front wheel 2FR, a left front drive motor 4FL in the left front wheel 2FL, a right rear drive motor 4RR in the right rear wheel 2RR, and a left rear drive motor 4RL in the left rear wheel 2RL. Yes.
These drive motors 4 are so-called outer rotor type in- hibits composed of a rotor 4a provided on the inner periphery of the wheel 2 and a stator 4b fixed to the vehicle body via a knuckle (not shown). It is a wheel motor.

  In the vehicle 1 having such an outer rotor type in-wheel motor, as shown in FIG. 2, the instantaneous rotation center O determined by the mounting position of the lower arm 6 and the mounting angle of the suspension 8 is the same as the conventional one. A portion for transmitting force from 2 to the vehicle body is a stator 4 b portion of the drive motor 4. Here, since the portion of the stator 4b can be approximated to a contact point between the wheel 2 and the ground, the contact point can be regarded as an action point A. From this, a line L1 drawn from the action point A to the instantaneous rotation center O. And the anti-squat angle αf, which is an angle between the operating point A and the horizontal line L2, is larger than the conventional one.

As a result, the outer rotor type in-wheel motor can have a large control width of the anti-squat.
The driving force of each driving motor 4 depends on the electric power supplied from the traveling battery 10 provided in the vehicle 1 via the inverters 12FR, 12FL, 12RR, 12RL corresponding to the driving motor 4. appear.

Further, the vehicle 1 has an APS (accelerator position sensor) 14 that detects an accelerator operation amount, a BPS (brake position sensor) 16 that detects a brake operation amount, and a G sensor 20 that detects acceleration acting on the vehicle 1 (acceleration / deceleration detection). Means).
Vehicle height sensors 22F and 22R (also referred to as vehicle height sensors 22) are provided on the vehicle body front side (front) and vehicle body rear side (rear), respectively. The vertical displacement from the reference position before and after the vehicle body 1 is detected (pitching detection means). Here, the reference position is based on the vehicle body posture when the vehicle 1 is stopped, for example.

The vehicle 1 is equipped with a TCU (torque control unit) 30 (driving force control means) for controlling the driving force generated by each driving motor 4, and the TCU 30 includes the inverters 8, the APS 14, It is connected to various devices such as the BPS 16, the G sensor 20, and the vehicle height sensors 22.
The operation of the vehicle control apparatus for an electric vehicle according to the present invention configured as described above will be described below.

Referring to FIGS. 3 and 4, a driving force control routine of each driving motor 4 executed in the TCU 30 is shown in a flowchart, and will be described below based on the flowchart.
The driving force that is increased or decreased by the driving force control is limited to a predetermined value (for example, within 20% of the driving force required for acceleration / deceleration) in order to secure the driving force required for acceleration / deceleration. .

First, in step S1, it is determined from the G sensor 20 whether or not a lateral acceleration (hereinafter referred to as a lateral G) of the vehicle acting on the vehicle 1 is acting. When the determination result is false (No), that is, when the vehicle 1 is turning, the routine is exited. On the other hand, if the determination result is true (Yes), the process proceeds to step S2.
In step S <b> 2, it is determined whether or not the vehicle 1 is in an acceleration operation state by detecting acceleration in the vehicle longitudinal direction acting on the vehicle 1 from the G sensor 20. If the determination result is true (Yes), the process proceeds to step S3.

In step S3, the vertical displacement of the front is detected from a vehicle height sensor 22F provided at the front of the vehicle 1, and it is determined whether or not the front is displaced upward, that is, whether it is in an elevated state. If the determination result is true (Yes), the process proceeds to step S4. On the other hand, if the determination result is false (No), the process proceeds to step S10.
In step S4 and step S10, the vertical displacement of the rear is detected from a vehicle height sensor 22R provided on the rear of the vehicle 1, and it is determined whether the rear is displaced downward, that is, whether it is in a lowered state. .

In step S4, if the determination result is true (Yes), that is, if the front of the vehicle 1 is raised and the rear is lowered, the process proceeds to step S5.
In step S5, the driving force of the driving motors 4FR and 4FL provided in the front wheels 2FR and 2FL is increased, and the driving motors 4RR and 4RL provided in the rear wheels 2RR and 2RL are increased. Increase the driving force and exit the routine.

In step S4, if the determination result is false (No), that is, if only the front of the vehicle 1 is rising, the process proceeds to step S6.
In step S6, the driving force of the driving motors 4FR and 4FL provided in the front wheels 2FR and 2FL is increased, and the routine is exited.
If the determination result is true (Yes) in step S10, that is, if only the rear of the vehicle 1 is descending, the process proceeds to step S11.

In step S11, the driving power of the drive motors 4RR and 4RL provided in the rear wheels 2RR and 2RL is increased, and the routine is exited.
Further, in step S10, when the determination result is false (No), that is, when the front of the vehicle 1 is not raised and the rear is not lowered, that is, when the vehicle 1 is not pitched due to acceleration, the routine is executed. Exit.

  As described above, when the vehicle 1 is accelerated, the driving force of the front wheels 2FR, 2FL is increased according to the rise of the front of the vehicle 1, and the driving force of the rear wheels 2RR, 2RL is increased according to the rise of the rear. Thus, it is possible to improve the anti-squat force, which is generated by the driving force and works downward on the front and upward on the rear, and suppresses the front rising and rear lowering.

On the other hand, if the determination result of whether or not the vehicle 1 is in the acceleration operation state is false (No) in step S2, the process proceeds to step S20.
In step S20, it is determined whether or not the vehicle 1 is in a decelerating operation state by detecting acceleration in the vehicle longitudinal direction acting on the vehicle 1 from the G sensor 20. When the determination result is false (No), that is, when the vehicle is in steady running, the routine is exited. On the other hand, if the determination result is true (Yes), the process proceeds to step S21.

In step S21, the vertical displacement of the front is detected from a vehicle height sensor 22F provided at the front of the vehicle 1, and it is determined whether or not the front is in a lowered state. If the determination result is true (Yes), the process proceeds to step S22. On the other hand, if the determination result is false (No), the process proceeds to step S30.
In step S22 and step S30, a vertical displacement of the rear is detected from a vehicle height sensor 22R provided on the rear of the vehicle 1, and it is determined whether or not the rear is in an ascending state.

In step S22, if the determination result is true (Yes), that is, if the front of the vehicle 1 is lowered and the rear is raised, the process proceeds to step S23.
In step S23, the driving force of the driving motors 4FR and 4FL provided in the front wheels 2FR and 2FL is reduced, and the driving motors 4RR and 4RL provided in the rear wheels 2RR and 2RL are reduced. Decrease the driving force and exit the routine.

In step S22, if the determination result is false (No), that is, if only the front of the vehicle 1 is descending, the process proceeds to step S24.
In step S24, the driving force of the drive motors 4FR and 4FL provided in the front wheels 2FR and 2FL is decreased, and the routine is exited.
If the determination result is true (Yes) in step S30, that is, if only the rear of the vehicle 1 is rising, the process proceeds to step S31.

In step S31, the driving force of the drive motors 4RR and 4RL provided in the rear wheels 2RR and 2RL is decreased, and the routine is exited.
Furthermore, if the determination result is false (No) in step S30, that is, if the front of the vehicle 1 is not lowered and the rear is not raised, that is, if the vehicle 1 is not pitching, the routine is exited. .

  As described above, when the vehicle 1 is decelerated, the driving force of the front wheels 2FR, 2FL is decreased according to the lowering of the front of the vehicle 1, and the driving force of the rear wheels 2RR, 2RL is decreased as the rear is raised. Thus, the anti-squat force, which is generated by the driving force and works downward at the front and upward at the rear, can be reduced, and the lowering of the front and the rear can be suppressed.

Thus, according to the pitching at the time of acceleration / deceleration of the vehicle 1, the pitching can be suppressed by controlling the driving force of both or either of the front wheels 2FR, 2FL and the rear wheels 2RR, 2RL.
Further, since the vehicle 1 is an outer rotor type four-wheel in-wheel motor electric vehicle, the driving force can be controlled independently for each wheel, and the control range of the anti-squat by the driving force control is large and sufficient. A pitching suppression effect can be obtained.

As a result, the riding comfort of the vehicle 1 can be improved.
Further, the driving force used for suppressing the pitching is limited so as to ensure the amount necessary for acceleration / deceleration, so that the running stability of the vehicle 1 can be maintained without impeding the acceleration / deceleration of the vehicle 1. .
Here, when the change amount of the accelerator operation amount and the brake operation amount detected by the APS 14 and the BPS 16 (acceleration / deceleration prediction means) is a predetermined value or more, the degree of vertical change in the front and rear of the vehicle 1 caused by the acceleration / deceleration. It is also possible to control the driving force of the driving motor 4 for the front wheels 2FR, 2FL and the rear wheels 2RR, 2RL so as to attenuate. For example, if the accelerator operation amount change detected by the APS 14 is greater than or equal to a predetermined value when a sudden accelerator operation is performed, the front wheels 2FR, 2FL are set so as to attenuate the degree to which the front is suddenly raised and the rear is lowered. The driving force of the rear wheels 2RR and 2RL is decreased. By doing so, the same effect as that of a general damper can be obtained by controlling the driving force.

Although the description of the embodiment of the vehicle control apparatus for an electric vehicle according to the present invention is finished as above, the embodiment is not limited to the above embodiment.
For example, in the above embodiment, the vertical displacement in the front-rear direction of the vehicle body is detected by the vehicle height sensors 22F and 22R. However, any device that can detect the pitching of the vehicle body may be used. You may make it do.

In the above embodiment, the G sensor 20 is used as a means for detecting acceleration / deceleration. However, the present invention is not limited to this, and an APS 14 or BPS 16 may be used.
Moreover, in the said embodiment, although acceleration / deceleration is estimated using APS14 or BPS16, it is not restricted to this, You may use another apparatus.

It is a schematic block diagram of the vehicle provided with the vehicle control apparatus which concerns on this invention. It is a schematic diagram which shows the anti squat angle of the vehicle which concerns on this invention. It is a part of flowchart which shows the driving force control routine of each drive motor performed in TCU in the vehicle control apparatus of the electric vehicle which concerns on this invention. FIG. 4 is the remaining part of the flowchart showing the control routine following FIG. 3. FIG. It is a schematic diagram which shows the anti squat angle in a common vehicle.

Explanation of symbols

1 vehicle 2 wheel 4 drive motor (traveling drive motor)
14 APS (acceleration / deceleration prediction means)
16 BPS (acceleration / deceleration prediction means)
20 G sensor (acceleration / deceleration detection means)
22 Vehicle height sensor (pitching detection means)
30 TCU (driving force control means)

Claims (4)

A driving motor for driving the wheels provided on the front and rear wheels of the vehicle;
Acceleration / deceleration detecting means for detecting an acceleration / deceleration state of the vehicle;
Pitching detection means for detecting vertical displacement of the vehicle longitudinally of the vehicle;
When the acceleration state of the vehicle is detected by the acceleration / deceleration detection means, the driving force of the traveling drive motor for the front wheels is increased in accordance with the upward displacement of the front side of the vehicle body detected by the pitching detection means. And / or a control for increasing the driving force of the travel driving motor of the rear wheels in accordance with the downward displacement of the rear side of the vehicle body detected by the pitching detection means. Force control means;
A vehicle control device for an electric vehicle, comprising: A driving motor for driving the wheels provided on the front and rear wheels of the vehicle;
Acceleration / deceleration detecting means for detecting an acceleration / deceleration state of the vehicle;
Pitching detection means for detecting vertical displacement of the vehicle longitudinally of the vehicle;
When the deceleration state of the vehicle is detected by the acceleration / deceleration detecting means, the driving force of the traveling drive motor for the front wheels is reduced according to the downward displacement of the front side of the vehicle body detected by the pitching detecting means. control to, and driven in response to said direction of displacement on the detected vehicle body rear side by the pitching detection means, performs both or either of the control for reducing the driving force by the driving motor for driving the rear wheel Force control means;
The vehicle control apparatus for an electric vehicle characterized by comprising a. 3. The vehicle control device for an electric vehicle according to claim 1, wherein the driving force to be increased or decreased by the driving force control means is limited within a predetermined range. Furthermore, an acceleration / deceleration prediction means for predicting acceleration / deceleration of the vehicle is provided,
When the acceleration / deceleration change detected by the acceleration / deceleration predicting means is equal to or greater than a predetermined value, the driving force control means is configured to reduce the degree of vertical change in the longitudinal direction caused by the acceleration / deceleration. electric motor vehicle control device according to claim 1, wherein the controller controls the driving force of a motor.

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