JP2017079517A - Vehicle control device - Google Patents

Abstract

To provide a vehicle control device capable of appropriately suppressing vertical vibration regardless of the disturbance condition of a front wheel. A vehicle control device includes a front wheel and a rear wheel suspended on a vehicle body via a suspension mechanism, an in-wheel motor, a stroke sensor, and an ECU. The ECU has a vertical displacement of the front wheel. A vertical displacement estimator 61 for estimating the vertical displacement of the rear wheel based on the above, a control command value calculator 62 for calculating the front wheel and rear wheel control command values based on the vertical displacement of the front wheel and the vertical knitting of the rear wheel, When the sign of the control command value for the front wheels is opposite to the sign of the control command value for the rear wheels, no braking / driving force is generated for the front wheels and the rear wheels, or the control command value for the rear wheels for the rear wheels A braking / driving force corresponding to a control command value obtained by subtracting a predetermined value from the braking / driving force that generates a braking / driving force in the opposite direction and the same magnitude as the braking / driving force generated on the rear wheels relative to the front wheels. Force control unit 6 And, equipped with a. [Selection] Figure 2

Description

  The present invention relates to a vehicle control device.

  2. Description of the Related Art An in-wheel motor type vehicle is known in which a motor is disposed in or near a wheel in each wheel of the vehicle and the driving force and braking force of each wheel are independently controlled. For example, in Patent Document 1, in an in-wheel motor vehicle, the vertical force generated in the vehicle body is utilized based on the arrangement of the suspension mechanism by controlling the driving force and braking force (braking / driving force) of the driving wheels. A vehicle control device that suppresses vertical vibration (bouncing) of the vehicle body is disclosed.

JP 2006-109642 A

  In the vehicle control device in Patent Document 1, when performing braking / driving force control for suppressing vertical vibration of the vehicle body caused by disturbance from the road surface, the braking / driving force generated on the front wheel side is opposite to the braking / driving force generated on the rear wheel side. It was necessary to generate a braking / driving force in the same direction and in the same magnitude. In other words, the direction and magnitude of the braking / driving force of the front wheels when suppressing vertical vibrations of the vehicle body is determined according to the braking / driving force of the rear wheels, regardless of the disturbance state of the front wheels. Therefore, it may be difficult for the vehicle control device in Patent Document 1 to obtain the targeted effect depending on the disturbance condition of the front wheels.

  The present invention has been made in view of the above, and an object of the present invention is to provide a vehicle control device that can appropriately suppress vertical vibration regardless of the disturbance state of the front wheels.

  In order to solve the above-described problems and achieve the object, a vehicle control device according to the present invention is provided for a front wheel and a rear wheel suspended on a vehicle body via a suspension mechanism, and for the front wheel and the rear wheel, respectively. By controlling the braking / driving force generating mechanism, the braking / driving force generating mechanism for independently generating the braking / driving force including the driving force and the braking force, the vertical displacement detecting means for detecting the vertical displacement of the front wheel, and the braking / driving force generating mechanism, Control means for suppressing vertical vibrations of the vehicle body, wherein the control means includes vertical displacement estimation means for estimating vertical displacement of the rear wheel based on vertical displacement of the front wheel, and vertical displacement of the front wheel. A control command value calculating means for calculating the control command value for the front wheel based on the vertical displacement of the rear wheel, and a control command value calculating means for calculating the control command value for the rear wheel based on the vertical displacement of the rear wheel; The braking / driving force corresponding to the control command value for the rear wheel is generated for the rear wheel, and the braking / driving force generated for the rear wheel for the front wheel is in the opposite direction and the same magnitude. Braking / driving force control means for generating braking / driving force, wherein the braking / driving force control means has a sign of the control command value for the front wheel calculated by the control command value calculating means. In the case where the sign is opposite, the braking / driving force is not generated for the front wheel and the rear wheel, or the control command value is obtained by subtracting a predetermined value from the control command value for the rear wheel for the rear wheel. A corresponding braking / driving force is generated, and a braking / driving force in the opposite direction and the same magnitude as the braking / driving force generated on the rear wheel is generated with respect to the front wheel.

  Accordingly, the vehicle control device can appropriately suppress the vertical vibration of the vehicle body regardless of the front wheel disturbance state by switching the control in consideration of the front wheel disturbance state.

  According to the vehicle control device of the present invention, the vertical vibration of the vehicle body can be appropriately suppressed regardless of the disturbance condition of the front wheels, so that the riding comfort of the vehicle can be improved.

FIG. 1 is a diagram illustrating a configuration of a vehicle including a vehicle control device according to an embodiment of the present invention and forces acting on the vehicle. FIG. 2 is a block diagram showing a configuration of the vehicle control device according to the embodiment of the present invention. FIG. 3 is a diagram illustrating a response delay of the rear wheel with respect to the front wheel in the vertical vibration attenuation reduction control. FIG. 4 is a diagram illustrating forces generated on the front wheels and the rear wheels in the attenuation reduction control of the vertical vibration. FIG. 5 is a flowchart showing an example of the vertical vibration attenuation reduction control by the vehicle control apparatus according to the embodiment of the present invention. FIG. 6 is a graph showing a control command value calculated from the front wheel stroke speed and a control command value calculated from the rear wheel stroke speed in the vertical vibration attenuation reduction control. FIG. 7 is a flowchart showing another example of vertical vibration attenuation reduction control by the vehicle control apparatus according to the embodiment of the present invention.

  A vehicle control device according to an embodiment of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  The vehicle control device is mounted on an in-wheel motor vehicle. As shown in FIGS. 1 and 2, the vehicle 1 includes four suspension mechanisms 20, two front wheels 31, two rear wheels 32, four in-wheel motors (braking / driving force generating mechanisms) 40, A stroke sensor (vertical displacement detection means) 50 and an ECU (Electronic Control Unit: control means) 60 are provided. Here, the vehicle control device includes at least the suspension mechanism 20, the in-wheel motor 40, the stroke sensor 50, and the ECU 60.

  The suspension mechanism 20 includes, for example, a strut type suspension including a shock absorber with a built-in shock absorber, a coil spring, and a suspension arm, and a wishbone type suspension including a coil spring, a shock absorber, and upper and lower suspension arms. Can be used.

  As shown in FIG. 1, the front wheel 31 and the rear wheel 32 are suspended from the vehicle body 10 via independent suspension mechanisms 20. Further, in-wheel motors 40 are respectively provided in the front wheels 31 and the rear wheels 32.

  The in-wheel motor 40 generates a driving force or a braking force (regenerative braking force) for the front wheel 31 and the rear wheel 32 independently of each other. The in-wheel motor 40 is composed of a brushless motor, for example, and is connected to a battery (not shown) via a motor driver (not shown). The force including the driving force and the braking force is defined herein as “braking / driving force”.

  The in-wheel motor 40 is driven and controlled by being supplied with AC power from a motor driver, and generates driving force for the front wheels 31 and the rear wheels 32. Thus, the operation of supplying electric power to the in-wheel motor 40 to generate the drive torque is called powering.

  The in-wheel motor 40 also functions as a generator, and can regenerate the power generated by the rotational energy of the front wheels 31 and the rear wheels 32 to the battery via the motor driver. The braking torque generated by the power generation of the in-wheel motor 40 generates a braking force for the front wheels 31 and the rear wheels 32.

  The stroke sensor 50 detects the vertical displacement of the front wheel 31 and the rear wheel 32. The stroke sensor 50 is provided in each of the front wheel 31 and the rear wheel 32, and specifically detects the stroke speed of each suspension mechanism 20.

  Although not shown, the vehicle 1 includes a steering angle sensor, an accelerator sensor, a throttle sensor, a brake sensor, a sprung vertical acceleration sensor, a lateral acceleration sensor, a vehicle speed sensor, a yaw rate sensor, a pitch rate sensor, a roll rate sensor, and the like. I have.

  The ECU 60 has a microcomputer composed of a CPU, a ROM, a RAM, and the like as main components, and executes various programs. As shown in FIG. 2, signals from various sensors including the stroke sensor 50 are input to the ECU 60. Further, as shown in FIG. 2, the ECU 60 includes a vertical displacement estimation unit (vertical displacement estimation unit) 61, a control command value calculation unit (control command value calculation unit) 62, and a braking / driving force control unit (braking / driving force control). Means) 63. The description of these configurations will be described later.

(Outline of attenuation reduction control of vertical vibration)
Hereinafter, an outline of the attenuation reduction control (braking / driving force control) of the vertical vibration will be described with reference to FIGS. 1 and 3. Here, the attenuation reduction control of the vertical vibration is a control for improving the riding comfort by controlling the in-wheel motor 40 to suppress the vertical vibration of the vehicle 1.

As shown in FIG. 1, the front wheel 31 and the rear wheel 32 of the vehicle 1 are connected to the vehicle body 10 via the suspension mechanism 20. Generally, the instantaneous rotation center _Xf of the suspension mechanism 20 on the side of the front wheel 31 that connects the front wheel 31 to the vehicle body 10 is located behind and above the front wheel 31, and the rear wheel 32 that connects the rear wheel 32 to the vehicle body 10. instantaneous center of rotation X _r side of the suspension mechanism 20, rather than the rear wheel 32 located in front of and above.

Therefore, as shown in FIG. 1, when driving torque is applied from the in-wheel motor 40 to the front wheels 31, a braking / driving force (driving force) F _f1 forward to the grounding point of the front wheels 31 with respect to the traveling direction of the vehicle 1. The braking / driving force F _f1 generates a vertical force Ff ₁₁ that urges downward in the vertical direction via the suspension mechanism 20 at the ground contact point of the front wheel 31. Therefore, by driving the front wheel 31, a force in the direction of sinking the vehicle body 10 acts. Conversely, when braking torque is applied to the front wheel 31 from the in-wheel motor 40, a braking / driving force (braking force) F _f2 facing backward in the traveling direction of the vehicle 1 acts on the ground contact point of the front wheel 31, and this force Due to F _f2 , a vertical force F _f21 that urges upward in the vertical direction via the suspension mechanism 20 is generated at the ground contact point of the front wheel 31. Therefore, by braking the front wheel 31, a force in the direction of lifting the vehicle body 10 is applied.

On the other hand, with respect to the rear wheel 32, the vertical force is generated in the opposite direction to the front wheel 31. That is, as shown in FIG. 1, when driving torque is applied from the in-wheel motor 40 to the rear wheel 32, a forward force (driving force) F _{r1 with} respect to the traveling direction of the vehicle 1 at the ground contact point of the rear wheel 32. The driving force F _r1 generates a vertical force F _r11 urging vertically upward via the suspension mechanism 20 at the ground contact point of the rear wheel 32. Therefore, by driving the rear wheel 32, a force in a direction to lift the vehicle body 10 acts. Conversely, when a braking torque is applied from the in-wheel motor 40 to the rear wheel 32, a rearward force (braking force) _Fr2 acts on the ground contact point of the rear wheel 32 with respect to the traveling direction of the vehicle 1, and this braking is applied. Due to the power F _r2 , a vertical force F _r21 that urges downward in the vertical direction via the suspension mechanism 20 is generated at the ground contact point of the rear wheel 32. Therefore, by braking the rear wheel 32, a force in the direction of sinking the vehicle body 10 is applied.

  In the vertical vibration attenuation reduction control, the front wheel 31 and the rear wheel 32 are independently converted into the front wheel 31 and the rear wheel 32 by the in-wheel motor 40 using the action of converting the braking / driving force of the front wheel 31 and the rear wheel 32 into the vertical force. By generating braking / driving force, vertical vibration is suppressed.

In the vertical vibration attenuation reduction control, the braking / driving force is controlled based on the rear wheel 32 side. For example, as shown in FIG. 1, the angle formed between the ground point of the front wheel 31 and the instantaneous rotation center _Xf and the ground horizontal plane is θ _f , and the ground point of the rear wheel 32 and the instantaneous rotation center _Xr are connected. When the angle between the line and the ground plane is θ _r , the magnitude of the vertical force on the front wheel 31 side is F _f tan θ _f , and the magnitude of the vertical force on the rear wheel 32 side is F _r tan θ _r . That is, F _f tan θ _f and F _r tan θ _r are conversion rates for converting the braking / driving force generated at the front wheels 31 and the rear wheels 32 into the vertical force of the vehicle body 10.

Here, in a general vehicle, as shown in FIG. 1, the structure of the suspension mechanism 20, theta is larger theta _r as compared with _{f (θ f <θ r)} . Therefore, the conversion rate of the vertical force is greater on the rear wheel 32 side than on the front wheel 31 side. That is, the range of the vertical force that can be generated by controlling the braking / driving force of the rear wheel 32 is larger than the range of the vertical force that can be generated by controlling the braking / driving force of the front wheel 31. Therefore, in the damping reduction control of the vertical vibration, the braking / driving force is controlled based on the rear wheel 32 side.

Specifically, when the vehicle 1 travels on a road surface where the disturbance Z ₀ exists as shown in FIG. 3, the front wheel 31 and the rear wheel 32 pass through the disturbance Z ₀ in this order. when passing through the _zero without control of the braking-driving force of the front wheels 31, rear wheels 32 and controls the braking and driving force of the rear wheel 32 when passing through the disturbance Z _0. At that time, braking-driving force is generated in the rear wheel 32 (and the vertical force based on the braking-driving force), the front wheel 31 is the magnitude of the vertical displacement when passing through the disturbance Z ₀ (for example, the front wheel 31 side suspension mechanism 20 Is calculated based on the stroke speed).

When the rear wheel 32 passes through the disturbance Z ₀ , the in-wheel motor 40 generates braking / driving force (and vertical force based on this braking / driving force) on the rear wheel 32, and is provided on the rear wheel 32 side. Vertical vibration is suppressed by extending and contracting the suspension mechanism 20. At that time, if a braking / driving force is generated only on the rear wheel 32, a longitudinal force (front / rear fluctuation) is generated. Therefore, a braking / driving force is generated on the rear wheel 32, and at the same time, a rear wheel is applied to the front wheel 31. A braking / driving force having the same magnitude as that of the braking / driving force generated in the direction 32 is generated in the reverse direction. Thereby, it is possible to suppress vertical vibration while suppressing generation of longitudinal force.

Here, as described above, in the conventional vehicle control device, it may be difficult to suppress the vertical vibration depending on the road surface where the front wheels 31 and the rear wheels 32 are grounded. For example, in the case of the road surface as shown in FIG. 4, the rear wheel 32 side, because of the upward slope in the direction of travel, the braking-driving force to the rear wheel 32 (driving force) is generated F _r1, vertical force in the vertical upward direction F _r11 is generated. On the front wheel 31 side, in order to suppress the generation of the longitudinal force, the braking / driving force (braking force) F _f2 having the same magnitude and the reverse direction as the braking / driving force (driving force) F _r1 generated on the rear wheel 32. And a vertical upward force F _f21 is generated. As described above, the control for generating the braking / driving force that always cancels the braking / driving force on the rear wheel 32 side on the front wheel 31 side is effective, for example, on a road surface with a moderate (small) disturbance as shown in FIG. It is. However, as shown in FIG. 4, there is a case where the vertical vibration of the vehicle body 10 is deteriorated on a road surface with a strong (large) disturbance in which a large upward gradient and a large downward gradient are continuous.

For example, as shown in FIG. 4, when the front wheel 31 is traveling on a descending slope when the rear wheel 32 is traveling on an ascending slope, the vertical force F _f11 (downward in the vertical direction on the front wheel 31 side) It is necessary to extend the suspension mechanism 20 in the direction of the gradient by generating a broken-line circle frame in FIG. However, in the conventional control, since the braking / driving force that always cancels the braking / driving force on the rear wheel 32 side is generated on the front wheel 31 side, as shown in FIG. A vertical upward force F _f21 is generated in the vertical direction, and the suspension mechanism 20 is contracted. Thereby, the vertical vibration of the vehicle body 10 is deteriorated.

  Therefore, the above problem is avoided by switching the control according to the disturbance situation on the front wheel 31 side. Hereinafter, control by the vehicle control apparatus according to the present embodiment will be described with reference to FIGS. 5 and 6.

The vehicle control apparatus according to the present embodiment first detects the stroke speed of the front wheel 31 (hereinafter referred to as front wheel stroke speed) by the stroke sensor 50, and the vertical displacement estimation unit 61 of the ECU 60 determines the rear wheel speed based on the front wheel stroke speed. A stroke speed (hereinafter referred to as rear wheel stroke speed) is estimated (step S1). Here, as shown in FIG. 3, the disturbance Z _{0 at} the contact point of the front wheel 31 also acts on the rear wheel 32 after Δt seconds. Accordingly, the vertical displacement estimation unit 61 estimates the front wheel stroke speed before Δt seconds as the rear wheel stroke speed at the present time.

The delay time Δt of the disturbance Z ₀ can be calculated by, for example, “Δt = wheel base / vehicle speed + delay time compensation value”. The “delay time compensation value” is a correction value set based on, for example, fluctuations in the wheel speed of the rear wheel 32, and the ECU 60 associates the delay time compensation value with fluctuations in the wheel speed of the rear wheel 32. Previously stored maps. Thus, by including the delay time compensation value in the delay time Δt, the rear wheel stroke speed can be estimated in real time.

Subsequently, the control command value calculation unit 62 of the ECU 60 calculates the control command value M _f of the front wheel 31 based on the front wheel stroke speed, and calculates the control command value M _r of the rear wheel 32 based on the rear wheel stroke speed. (Step S2). Here, the “control command value” indicates a required value for causing the in-wheel motor 40 to generate braking / driving force on the front wheels 31 and the rear wheels 32. The ECU 60 holds a map that associates the stroke speed with the control command value in advance, and the control command value calculation unit 62 refers to this map to control the control command value M _f for the front wheels 31 and the control command value for the rear wheels 32. to calculate the M _r.

Subsequently, the braking / driving force control unit 63 of the ECU 60 determines that the control command value M _{f for the} front wheels 31 and the control command value M _{r for the} rear wheels 32 have a relationship of “| M _f −M _r | ≧ | M _r |”. It is determined whether or not it is satisfied (step S3). This step S3 determines whether or not the sign of the control command value M _f of the front wheel 31 calculated by the control command value calculating unit 62 is opposite to the sign of the control command value _Mr of the rear wheel 32. It is.

Here, FIG. 6 is a graph showing the control command value M _{f for the} front wheel 31 and the control command value M _{r for the} rear wheel 32, respectively. As regions indicated by circled in the figure, the part code and is in the reverse control command value M _r of the code and the rear wheel 32 of the control command value M _f of the front wheel 31 on the time axis, As shown in FIG. 4 described above, the vehicle 1 is traveling in a place where the disturbance on the road surface is intense such that the front wheel 31 side is a downward slope and the rear wheel 32 side is an upward slope.

Therefore, the braking / driving force control unit 63 determines in step S3 whether or not the relationship of “| M _f −M _r | ≧ | M _r |” is satisfied, whereby the control command value M _f of the front wheel 31 is determined. It is determined whether or not the sign is opposite to the sign of the control command value _Mr of the rear wheel 32. Incidentally, in the conventional vehicle control device is calculated only control command value M _r of the rear wheels 32, but was not used control command value M _f of the front wheel 31, the vehicle control apparatus according to this embodiment, step In S3, it is used as a material for judging the disturbance state of the front wheel 31.

When the control command value M _f of the front wheel 31 and the control command value M _r of the rear wheel 32 satisfy the relationship “| M _f −M _r | ≧ | M _r |” (Yes in step S3), since the disturbance is severe, the braking-driving force control unit 63, in-wheel to the motor 40, the control command value by subtracting a predetermined value from the control command value M _r of the rear wheels 32 α × M _{r (where,} alpha <1) Is output (step S4). The braking / driving force control unit 63 generates a braking / driving force corresponding to the control command value α × M _r of the rear wheel 32 for the rear wheel 32 and is generated for the rear wheel 32 for the front wheel 31. The braking / driving force control is executed by generating the braking / driving force in the opposite direction to the braking / driving force to be performed (step S6), and the process is terminated.

On the other hand, when the control command value M _f of the front wheel 31 and the control command value M _r of the rear wheel 32 do not satisfy “| M _f −M _r | ≧ | M _r |” (No in step S3), the front wheel 31 since disturbance is gentle, the braking-driving force control unit 63 outputs a control command value M _r of the rear wheel 32 relative to the in-wheel motor 40 (step S5). Then, braking-driving force control unit 63, to the rear wheel 32, together to generate a braking driving force corresponding to the control command value M _r of the rear wheel 32, and regulations against the front wheel 31, is generated in the rear wheel 32 The braking / driving force control is executed by generating the braking / driving force in the direction opposite to that of the driving force (step S6), and the process is terminated.

  By performing the control as described above, the vehicle control apparatus according to the present embodiment switches the control in consideration of the disturbance state of the front wheel 31, so that the vertical vibration of the vehicle body 10 is performed regardless of the disturbance state of the front wheel 31. Can be appropriately suppressed, and thereby the ride comfort of the vehicle 1 can be improved.

In the example of FIG. 5, when the control command value M _f of the front wheel 31 and the control command value M _r of the rear wheel 32 satisfy the relationship “| M _f −M _r | ≧ | M _r |”, Although the control for reducing the braking / driving force generated from the rear wheel 32 side is performed, the braking / driving force control itself is not generated for the front wheel 31 and the rear wheel 32 as shown in FIG. 6, for example. May not be executed (step S7). Thereby, it is possible to reliably prevent the vertical vibration from deteriorating when the disturbance is intense, and to improve the riding comfort of the vehicle 1.

  The vehicle control apparatus according to the present invention has been described in detail with reference to the embodiments for carrying out the invention. However, the gist of the present invention is not limited to these descriptions, and is based on the descriptions in the claims. Must be interpreted widely. Needless to say, various changes and modifications based on these descriptions are also included in the spirit of the present invention.

  For example, in the vehicle control device according to the embodiment, the in-wheel motor 40 is exemplified as the braking / driving force generation mechanism, but an actuator capable of controlling the braking / driving force independently by the front wheels 31 and the rear wheels 32 may be used.

DESCRIPTION OF SYMBOLS 1 Vehicle 10 Car body 20 Suspension mechanism 31 Front wheel 32 Rear wheel 40 In-wheel motor (braking / driving force generating mechanism)
50 Stroke sensor (Vertical displacement detection means)
60 ECU (control means)
61 Vertical displacement estimation unit (Vertical displacement estimation means)
62 Control command value calculation unit (control command value calculation means)
63 Braking / driving force control section (braking / driving force control means)

Claims (1)

Front and rear wheels suspended on the vehicle body via a suspension mechanism;
A braking / driving force generating mechanism for generating braking / driving force consisting of driving force and braking force independently for the front wheel and the rear wheel;
Vertical displacement detecting means for detecting vertical displacement of the front wheel;
Control means for suppressing vertical vibrations of the vehicle body by controlling the braking / driving force generating mechanism;
In a vehicle control device comprising:
The control means includes
Vertical displacement estimating means for estimating the vertical displacement of the rear wheel based on the vertical displacement of the front wheel;
Control command value calculation means for calculating the control command value of the front wheel based on the vertical displacement of the front wheel, and calculating the control command value of the rear wheel based on the vertical displacement of the rear wheel;
The braking / driving force generating mechanism generates a braking / driving force corresponding to the control command value of the rear wheel for the rear wheel, and is opposite to the braking / driving force generated for the rear wheel with respect to the front wheel. And braking / driving force control means for generating a braking / driving force of the same magnitude;
With
When the sign of the control command value for the front wheel calculated by the control command value calculating means is opposite to the sign of the control command value for the rear wheel, the braking / driving force control means applies to the front wheel and the rear wheel. On the other hand, braking / driving force is not generated, or braking / driving force corresponding to a control command value obtained by subtracting a predetermined value from a control command value of the rear wheel is generated for the rear wheel, and the front wheel is A vehicle control device that generates a braking / driving force in the opposite direction and the same magnitude as the braking / driving force generated on the rear wheel.

Images