JP2016094139A - Vehicle speed estimation device of four-wheel drive vehicle and control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle speed estimation device of a four-wheel drive vehicle which can accurately estimate a vehicle speed at not only direct advance but also a turn, and is simple in an estimation procedure of the vehicle speed.SOLUTION: Each-wheel vehicle speed equivalent amount calculation means 6 is arranged which calculates a vehicle speed equivalent amount Vbeing a speed which is equivalent to a vehicle speed from a wheel angle speed ω in each wheel 2 by using a yaw angle speed γ of a vehicle 1. Means 7 is arranged which acquires a first vehicle speed change amount α' being a vehicle speed change amount per unit time of the vehicle speed equivalent amount which becomes minimum or maximum out of the vehicle speed equivalent amount Vaccording to a positive value or a negative value of the fore-and-aft acceleration of the vehicle 1. Vehicle speed estimation means 8 is arranged which acquires the vehicle speed V corresponding to the presence or absence of a slip by comparing an absolute value |α-α'| of a difference between a second vehicle speed change amount αbeing acceleration in a vehicle fore-and-aft direction and the first vehicle speed change amount α' with a threshold δ.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle speed estimation device for a four-wheel drive vehicle for estimating the vehicle speed of a four-wheel drive vehicle, and a vehicle drive control device using the same.

  The vehicle speed is detected accurately when traction control (control for maintaining grip when the vehicle is accelerated) or ABS control (control for maintaining grip when the vehicle is decelerated) (ABS: antilock brake system) is applied to the vehicle. Necessary. In a two-wheel drive vehicle, the vehicle speed is obtained from the rotational speed of the driven wheel. However, in a four-wheel drive vehicle, there is no driven wheel, so it is necessary to estimate the vehicle speed while judging the grip or slip of each wheel.

Conventionally, the following methods have been proposed as methods for estimating the vehicle speed of a four-wheel drive vehicle.
In Patent Document 1, the first vehicle speed change amount per unit time is calculated using the minimum wheel speed. Moreover, the vehicle acceleration which is a 2nd vehicle speed variation | change_quantity is calculated | required with vehicle-mounted G sensor. If the difference between the first vehicle speed change amount and the second vehicle speed change amount is small, it is determined that each wheel is gripping, and the pseudo vehicle speed is calculated using the first vehicle speed change amount. On the other hand, when the difference between the first vehicle speed change amount and the second vehicle speed change amount is large, it is determined that each wheel is slipping, and the pseudo vehicle speed is calculated using the second vehicle speed change amount.

  In Patent Document 2, a first upper limit acceleration is given to estimate the first vehicle speed from the wheel speed, a second upper limit acceleration is given to estimate the second vehicle speed from the minimum wheel speed, The vehicle speed is corrected and estimated by comparing the second vehicle speed.

Japanese Patent Laid-Open No. 04-293651 Japanese Patent Laid-Open No. 01-314656

The proposed technique of Patent Document 1 can accurately estimate the vehicle speed when the vehicle is moving straight ahead, but cannot accurately estimate the vehicle speed when the vehicle is turning.
In the proposed technique of Patent Document 2, the vehicle speed estimation procedure is complicated. Further, since the longitudinal acceleration of the vehicle is not used, it may be considered that the vehicle speed cannot be estimated with high accuracy.

An object of the present invention is to provide a vehicle speed estimation device for a four-wheel drive vehicle that can accurately estimate the vehicle speed not only when going straight but also when turning, and having a simple procedure for estimating the vehicle speed.
Another object of the present invention is to provide a vehicle drive control device capable of accurately and simply estimating the vehicle speed not only when going straight but also when turning, and appropriately performing traction control or ABS control.

A vehicle speed estimation device for a four-wheel drive vehicle according to the present invention is a device for estimating a vehicle speed in a four-wheel drive vehicle 1,
Using the yaw angular velocity γ of the vehicle 1 acquired from the sensor 4, a vehicle speed equivalent amount V _i ( _i : 1 to 4), which is a speed corresponding to the vehicle speed, is calculated from the rotational speed (for example, the wheel angular speed ω) at each wheel 2. Each wheel vehicle speed equivalent amount calculating means 6;
According to the sign of the longitudinal acceleration of the vehicle acquired from the sensor 4 or another sensor, the vehicle speed equivalent amount per unit time corresponding to the minimum value of the vehicle speed equivalent amounts V _i of the wheels 2 at the time of acceleration. A first vehicle speed change amount α _x ′ which is a vehicle speed change amount per unit time of a vehicle speed equivalent amount which is the maximum value of the vehicle speed equivalent amount V _i of each wheel 2 at the time of vehicle speed change amount and deceleration is obtained. First vehicle speed change amount calculating means 7;
Absolute value | α _x −α of the difference between the second vehicle speed change amount α _x and the first vehicle speed change amount α _x ′, which are accelerations in the vehicle longitudinal direction, acquired from any one of the sensors 4 or other sensors. _x ′ | is compared with a threshold value δ. When the longitudinal acceleration of the vehicle 1 is less than the threshold value δ, the minimum value of the vehicle speed equivalent amount V _i is obtained when the longitudinal acceleration of the vehicle 1 is accelerated, and The vehicle speed V is determined, and when the absolute value | α _x −α _x ′ | of the difference is equal to or larger than the threshold value δ, the vehicle speed V is obtained by integrating the second vehicle speed change amount α _x. Speed estimation means 8,
With.
The threshold value δ may be appropriately set based on the results of tests and simulations.

According to this configuration, the grip or slip of the wheel 2 during any travel including turning is determined using the rotational speed of the wheel 2, the longitudinal acceleration α _{x of} the vehicle 1, and the yaw angular velocity γ of the vehicle 1, and the determination result The vehicle speed V is estimated by selecting a calculation method according to the grip and the slip. In particular, since the amount of change in vehicle speed is calculated at each wheel 2 in consideration of the yaw angular velocity γ of the vehicle 1, the vehicle speed can be estimated even when the vehicle 1 is turning.

That is, each wheel vehicle speed equivalent amount calculation means 6 uses the yaw angular speed γ of the vehicle 1 to calculate a vehicle speed equivalent amount V _i that is a speed corresponding to the vehicle speed from the rotational speed (wheel angular speed ω) of each wheel 2. To do. The first vehicle speed change amount calculation means 7 obtains a first vehicle speed change amount α _x ′ that is a vehicle speed change amount per unit time. In this case, depending on the sign of the longitudinal acceleration of the vehicle, during acceleration of the vehicle speed change amount per unit time of the vehicle speed corresponding amount as the minimum value of the vehicle speed corresponding amount V _i of each wheel 2, during deceleration The vehicle speed change amount per unit time of the vehicle speed equivalent amount that is the maximum value among the vehicle speed equivalent amounts V _i of the wheels 2 is defined as a first vehicle speed change amount α _x ′.
Vehicle speed estimating means 8, the second vehicle speed change alpha _x and the first vehicle speed change alpha _x is a vehicle longitudinal acceleration obtained from the sensor _'absolute value of the difference between | α _x -α _x' By comparing | with the threshold value δ, the grip or slip of the wheel 2 is determined. Based on the determination result, the calculation method according to the grip and the slip is selected to estimate the vehicle speed V.
When the absolute value | α _x −α _x ′ | of the difference is less than the threshold value δ, it is considered that the vehicle is slipping, and the minimum value of the vehicle speed equivalent V _i when the vehicle 1 is accelerated. the determined by the vehicle speed V, the deceleration determines the maximum value of the vehicle speed corresponding amount V _i as the vehicle speed V. If you slip, thus out of the vehicle speed corresponding amount V _i of a four-wheel, in order to estimate the most actual vehicle speed corresponding amount V _i which are considered to be close to the speed of the vehicle speed V, a simple calculation method The vehicle speed V can be calculated with
Further, when the absolute value | α _x −α _x ′ | of the difference is equal to or larger than the threshold value δ, it can be considered that the vehicle is gripped. Therefore, the second vehicle speed change amount α _x is integrated and the vehicle is integrated. By obtaining the speed V, the vehicle speed V can be estimated accurately and easily.
Thus, the vehicle speed V can be accurately estimated not only when traveling straight but also when turning, and the estimation procedure of the vehicle speed V can be simplified.

In the present invention, the yaw angular velocity γ and the longitudinal acceleration of the vehicle 1 are acquired from the attitude sensor 4, and the rotational speed of the wheels 2 (wheel angular velocity ω) is a rotational sensor (for example, rotational) of the wheels 2 provided on the wheels 2. It may be acquired from the (angle sensor) 9.
The attitude sensor 4 is often used for various controls of the vehicle 1, and the attitude sensor 4 can be used for this vehicle speed estimation device. Further, the rotation sensor 9 for the wheel 2 is often provided for ABS control or the like, and the sensor can be used for this vehicle speed estimation device.

In the present invention, the traveling drive means 5 for driving the wheels 2 of the vehicle 1 may be an in-wheel motor drive device.
In the case of an in-wheel motor drive device, the braking / driving torque can be controlled with high accuracy by the motor. Therefore, by applying the vehicle speed estimation device of the present invention, the vehicle speed can be accurately adjusted even when turning while being four-wheel drive. The effect of being able to estimate well is exhibited more effectively in traction control and ABS control.

The vehicle drive control device of the present invention is a device for controlling the travel drive source 5 of the vehicle 1, and is a vehicle speed estimation device 10 for a four-wheel drive vehicle having any one of the above configurations of the present invention, and this vehicle speed estimation device. And traction control means 12 for performing traction control using the vehicle speed estimated in (1).
Since the vehicle speed estimation device 10 of the present invention can accurately estimate the vehicle speed V not only when traveling straight but also when turning as described above, and the estimation procedure of the vehicle speed V is simple, the vehicle speed estimation device of the present invention. By using 10 for the traction control, the traction control can be performed with high accuracy and efficiency while being four-wheel drive.

Another vehicle drive control device of the present invention is a vehicle drive control device that controls the vehicle 1, and is a vehicle speed estimation device 10 for a four-wheel drive vehicle having any one of the above configurations of the present invention, and this vehicle speed estimation device. And ABS control means 13 for performing ABS control using the vehicle speed V estimated at 10.
Since the vehicle speed estimation device 10 of the present invention can accurately estimate the vehicle speed not only when traveling straight but also when turning as described above, and the vehicle speed estimation procedure is simple, the vehicle speed estimation device 10 of the present invention is By using it for the ABS control, the ABS control can be effectively performed with high accuracy while being four-wheel drive.

  A vehicle speed estimation device for a four-wheel drive vehicle according to the present invention is a device for estimating a vehicle speed in a four-wheel drive vehicle, and uses the vehicle yaw angular velocity obtained from a sensor to determine the vehicle speed from the rotation speed provided on each wheel. Vehicle speed equivalent amount calculating means for calculating a vehicle speed equivalent amount that is a speed corresponding to the vehicle speed, and the vehicle of each wheel during acceleration according to the sign of the longitudinal acceleration of the vehicle acquired from the sensor or another sensor. The vehicle speed change amount per unit time of the vehicle speed equivalent amount that is the minimum value of the speed equivalent amount, and at the time of deceleration, the vehicle speed equivalent amount that is the maximum value of the vehicle speed equivalent amount of each wheel per unit time A first vehicle speed change amount calculating means for obtaining a first vehicle speed change amount that is a vehicle speed change amount; a second vehicle speed change amount that is an acceleration in the vehicle longitudinal direction acquired from any one of the sensors or other sensors; and When the absolute value of the difference from one vehicle speed change amount is compared with a threshold value and is less than the threshold value, and the longitudinal acceleration of the vehicle is accelerated, the minimum value of the vehicle speed equivalent amount is Includes a vehicle speed estimating means for determining the maximum value as a vehicle speed and, when the absolute value of the difference is equal to or greater than the threshold value, integrating the second vehicle speed change amount to obtain a vehicle speed, In addition to providing a vehicle speed estimation device for a four-wheel drive vehicle, the vehicle speed can be accurately estimated even when turning, and the vehicle speed estimation procedure is simple.

  According to the vehicle drive control device of the present invention, the vehicle speed can be estimated accurately and simply not only when traveling straight but also when turning, and traction control or ABS control can be appropriately performed.

It is a block diagram which shows the conceptual structure of the vehicle speed estimation apparatus of the four-wheel drive vehicle which concerns on one Embodiment of this invention. It is explanatory drawing of each direction used with the vehicle speed estimation apparatus. It is a flowchart which shows the flow of a process of the vehicle speed estimation apparatus. 4 is a graph showing a comparison between a vehicle speed estimation result obtained by the vehicle speed estimation device and an actual measurement value of the vehicle speed. It is a block diagram which shows the traction control and ABS control which use the vehicle speed estimated with the vehicle speed estimation apparatus. It is a block diagram which shows an example of a conceptual structure of the vehicle drive control apparatus using the traction control means and ABS control means of FIG. It is sectional drawing which shows an example of the in-wheel motor drive device which is the driving means for driving | running | working in the vehicle used as the control object of FIG.

  An embodiment of the present invention will be described with reference to the drawings. In FIG. 1, a vehicle 1 to which the vehicle speed estimation device 10 of this embodiment is applied is a four-wheel drive vehicle in which travel drive means 5 is individually provided for each wheel 2 as a front wheel and a rear wheel. The travel drive means 5 may be, for example, an in-wheel motor drive device as described later, or a motor provided on a chassis or an internal combustion engine. The vehicle speed estimation device 10 is provided as a part of the ECU 3 that performs overall cooperative control, overall control, and the like of the vehicle 1 in the example of FIG.

The vehicle speed estimation device 10 is constituted by each wheel vehicle speed equivalent amount calculation means 6, first vehicle speed change amount calculation means 7, and vehicle speed estimation means 8. In addition, a posture sensor 4 and a rotation angle sensor 9 are provided as sensors. The attitude sensor 4 is a sensor that detects the yaw angular velocity γ of the vehicle 1. Here, an acceleration sensor such as a gyro sensor that can detect both the yaw angular velocity γ and the longitudinal acceleration α _x of the vehicle 1 is used. Yes. The rotation angle sensor 9 is a sensor for detecting the rotation angular velocity α _x of each wheel 2, and may be provided for the wheel 2, wheel bearing or the like. May be a sensor that detects the rotational angular velocity of the motor. For example, a resolver.

Each wheel vehicle speed equivalent amount calculation means 6 uses the yaw angular velocity γ of the vehicle 1 acquired from the attitude sensor 4, and a vehicle speed equivalent amount V _i that is a speed corresponding to the vehicle speed from the wheel angular speed ω in each wheel 2. ( _I : 1 to 4) is calculated. The wheel angular velocity ω is acquired from the rotation angle sensor 9.

The first vehicle speed change amount calculation means 7 determines the minimum of the vehicle speed equivalent amounts V _i of the wheels 2 during acceleration according to the sign of the longitudinal acceleration α _x of the vehicle 1 acquired from the attitude sensor 4. vehicle speed change amount per unit time of the vehicle speed corresponding amount as a value, during deceleration the vehicle speed variation per unit of time the vehicle speed corresponding amount as the maximum value of the vehicle speed corresponding amount V _i of each wheel 2 A first vehicle speed change amount α _x ′ is obtained.

The vehicle speed estimator 8 calculates the absolute value | α _x of the difference between the second vehicle speed change amount α _x that is the acceleration in the vehicle longitudinal direction acquired from the attitude sensor 4 and the first vehicle speed change amount α _x ′. −α _x ′ | is compared with a threshold value δ. When the longitudinal acceleration of the vehicle 1 is accelerated, the minimum value of the vehicle speed equivalent V _i is reduced when the vehicle 1 is accelerated. The maximum value is determined as the vehicle speed V. When the absolute value | α _x −α _x ′ | of the difference is equal to or larger than the threshold value δ, the second vehicle speed change amount α _x is integrated to obtain the vehicle speed V. Ask. The threshold value δ is appropriately set based on the results of tests and simulations.
In the first vehicle speed variation calculation means 7 and the vehicle speed estimation means 8, the longitudinal acceleration (α _x ) of the vehicle 1 is an acceleration sensor provided separately from the attitude sensor 4 that detects the yaw angular velocity γ. You may make it acquire from (not shown).

Next, a vehicle speed estimation procedure performed by the vehicle speed estimation device 10 will be described using the flowchart of FIG.
In step S1, a vehicle speed equivalent speed V _i ( _i : 1 to 4) of each wheel, which is an amount corresponding to the vehicle speed, is calculated from each wheel angular speed ω of the vehicle 1 and yaw angular speed γ of the vehicle 1 to each wheel vehicle speed. The equivalent amount calculation means 6 calculates according to the following formula.

  R represents a wheel radius and d represents a tread. As shown in FIG. 2, the axis is vertically upward, and the direction of the yaw angular velocity when rotating counterclockwise around this axis is positive. In addition, the double sign in equation (1) is positive for the left wheel and negative for the right wheel. The subscript i represents the wheel 2 number. The angular velocity ω of the wheel 2 is obtained using the rotation angle sensor 9 of the wheel 2. The yaw angular velocity γ of the vehicle 1 is obtained from the attitude sensor 4 mounted on the vehicle.

Next, in step S2, by the first vehicle speed change calculating means 7, depending on the sign of the longitudinal acceleration alpha _x of the vehicle 1 obtained from the orientation sensor 4 (acceleration or deceleration), the vehicle speed change per unit time The corresponding amount α _x ′ (first vehicle speed change amount) is calculated by the following equation. That is, a value obtained by differentiating the minimum value or the maximum value of the vehicle speed equivalent amount is adopted as α _x ′ (step S3, step S4).

Thereafter, the following processes are performed by the vehicle speed estimation means 8.
In step S5, the longitudinal acceleration α _x obtained from the attitude sensor 4 is set as the second vehicle speed change amount, and the first vehicle speed change amount α _x ′ and the second vehicle speed change amount α _x are compared. If the absolute value | α _x −α _x ′ | of the difference is less than the threshold value δ as in the following equation, it is determined that at least one wheel is gripping, and if it is equal to or greater than the threshold value δ, Judge that all wheels are slipping.

一輪以上スリップしていると判断したときは、第二の車速変化量α_ｘの正負に基づき（ステップＳ６）、車両速度Ｖを次式で推定する。すなわち、車両１が加速しているときは車速相当量Ｖ_ｉの最小値を（ステップＳ７）、車両１が減速しているときは車速相当量Ｖ_ｉの最大値を車両速度Ｖとする（ステップＳ８）。

When it is determined that one or more wheels are slipping, the vehicle speed V is estimated by the following equation based on the sign of the second vehicle speed change amount α _x (step S6). That is, the minimum value of the vehicle speed corresponding amount V _i when the vehicle 1 is accelerating (step S7), and the maximum value of the vehicle speed corresponding amount V _i and the vehicle speed V when the vehicle 1 is decelerating (Step S8).

全輪スリップしていると判断したときは、次式の通り、第二の車速変化量α_ｘを積分して車両速度Ｖを推定する（ステップＳ９）。車両速度の初期値Ｖ０には、｜α_ｘ−α_ｘ′｜となる直前に、式（４）から求められる車両速度を用いる。

When it is determined that all wheels are slipping, the vehicle speed V is estimated by integrating the second vehicle speed change amount α _x as shown in the following equation (step S9). As the initial value V0 of the vehicle speed, the vehicle speed obtained from the equation (4) is used immediately before | α _x −α _x ′ |.

  In this way, by calculating the vehicle speed change amount for each wheel 2 in consideration of the yaw angular velocity γ of the vehicle 1, the vehicle speed V can be estimated even when the vehicle 1 is turning.

  FIG. 4B shows a result of estimating the vehicle speed in the deceleration slalom using the estimation method by the vehicle speed estimation device 10. FIG. 6A shows actual measurement values. It can be confirmed that the estimated vehicle speed is in good agreement with the actually measured one.

The above is an estimation method when a road surface with no inclination is assumed, but the longitudinal acceleration is corrected using the pitch angle and the vertical acceleration acquired as the output signal of the attitude sensor 4 even on the road surface with an inclination. If the vehicle speed is estimated in the same manner as described above, the vehicle speed can be estimated with high accuracy.
By accurately estimating the vehicle speed as described above, traction control and ABS control can be effectively applied to the vehicle.

Next, an example of traction control using the vehicle speed estimation device 10 of the above embodiment will be described with reference to FIGS. FIG. 5 is a block diagram of the traction control means 12. The traction control means 12 is provided on each wheel 2. The traction control means 12 sets the target slip ratio λ ^* in the target slip ratio setting means 14, obtains the difference (λ ^* −λ) from the actual slip ratio λ by the comparison unit 16, and controls the upper control. In accordance with the braking / driving torque Ta given from the means, the controller 17 generates a braking / driving torque T having a control amount corresponding to the difference (λ ^* −λ) in the slip ratio. If the difference (λ ^* −λ) in the slip ratio is zero, the controller 17 outputs the given braking / driving torque Ta as the braking / driving torque T as it is, and if the difference is not zero, a predetermined control is performed. The braking / driving torque T output from the input braking / driving torque Ta and the difference (λ ^* −λ) is calculated according to a rule.

The actual slip ratio lambda, the slip ratio calculating unit 15 calculates equations defined from the wheel speed V _i and the vehicle speed V, for example, in accordance with the following equation. As said vehicle speed V, the vehicle speed V calculated | required with the said vehicle speed estimation apparatus 10 demonstrated with FIGS. 1-3 was used.

Although FIG. 5 has been described as the traction control means 12, the same configuration is applied to the ABS control means 13 by regenerative control when the travel drive means 5 of FIG. However, the target slip ratio λ ^* set in the target slip ratio setting means 14 is set to about 0.1 to 0.2 in the case of traction control, and is set to about −0.2 to −0.1 in the ABS control. The braking / driving torque Ta that is input is a positive value in the case of traction control, and a negative value in the case of ABS control.

The traction control means 12 in FIG. 5 sets two types of values for traction control and ABS control as the target slip ratio λ ^{* in} the target slip ratio setting means 14 and determines whether the braking / driving torque Ta input is positive or negative. If the target slip ratio λ ^* output from the target slip ratio setting means 14 is switched in accordance with the control, the control means can be used for both traction control and ABS control. The control contents of the controller 17 are also calculated according to the positive / negative of the input braking / driving torque Ta.
When the traction control means 12 and the ABS control means 13 are separately provided in parallel, they are properly used according to the positive / negative of the input braking / driving torque Ta.

  Thus, by estimating the vehicle speed V using the vehicle speed estimation device 10 according to the embodiment of FIGS. 1 to 3 and calculating the slip ratio, the vehicle speed V can be accurately estimated even when turning. Thus, traction control and ABS control can be appropriately performed.

  FIG. 6 shows a conceptual configuration of a vehicle drive control device provided with the traction control means 12 of FIG. The example in the figure is basically the same as the example shown in FIG. 1, and the description of matters overlapping with those described with reference to FIG. 1 is omitted. In FIG. 6, the travel drive device 5 for each wheel 2 is an in-wheel motor drive device, and a specific example thereof will be described with reference to FIG.

  The traveling drive device 5 that is the in-wheel motor device of FIG. 1 includes a wheel bearing 26 that supports the wheel 2, a motor 25, and a rotating wheel that also serves as a hub for the wheel bearing 26 by decelerating the rotation of the motor 25. And a reduction gear 27 that transmits to the inner ring 26b, and a part thereof is located inside the wheel 2. The wheel bearing 26 is a rolling bearing in which a rolling element 26c is interposed between an outer ring 26a which is a fixed ring and the inner ring 26b. A brake rotor 23a of the brake device 23 is attached to the inner ring 26b, which is a rotating wheel, together with the wheel 2. An outer ring 26 a that is a fixed ring is attached to a common housing 28 of the motor 25 and the speed reducer 27. The motor 25 is, for example, an embedded magnet type synchronous motor, and includes a stator 29 fixed to the housing 28 and a rotor 30 rotatably supported on the housing 28 via a bearing. The stator 29 includes a stator coil. The rotor 30 is provided with a permanent magnet (not shown).

  In FIG. 6, the ECU 3 is a means for performing overall control of the entire vehicle as described above with reference to FIG. 1, and the ECU 3 is provided with a torque distribution means 19 and the vehicle speed estimation device 10. The torque distribution means 19 obtains the braking / driving torque of the entire vehicle according to the operation amounts of the accelerator operation means 21 such as an accelerator pedal and the brake operation means 22 such as a brake pedal, and the motor 25 of the travel drive apparatus 5 including each in-wheel motor apparatus. The braking / driving torque Ta is distributed to the inverter device 18 that controls.

  The inverter device 18 includes a power circuit unit 18a and a motor control unit 18b that controls the power circuit unit 18a. The power circuit unit 18a converts the DC power of a battery (not shown) into AC power for driving the motor 25, and control for controlling the inverter 20 by PWM control or the like in accordance with a current command from the motor control unit 18b. And a circuit unit (not shown).

  The motor control unit 18b has torque control means 32 for controlling the torque of the motor 25 by vehicle control or the like in accordance with the braking / driving torque Ta commanded from the torque distribution means 19 of the ECU 3, which is the upper control means. The current command generated in 32 is output to the power circuit unit 18a. In such a motor control unit 18b, the traction control means 12 and the ABS control means 13 described above with reference to FIG. The traction control means 12 and the ABS control means 13 perform the processing as shown in the example of FIG. 5 on the braking / driving torque Ta commanded from the torque distributing means 19 of the ECU 3 to generate the braking / driving torque T.

In FIG. 6, each brake 23 provided for each wheel 2 is controlled by a brake control means 31. Although the brake control means 31 is described outside the ECU 3 in the drawing, a part or the whole of the brake control means 31 is provided in the ECU 3. The brake control means 31 shown in FIG. 1 performs braking by each brake 23 and regeneration by each motor 5 from information such as various traveling conditions obtained by the ECU 3 in accordance with a braking command based on an operation amount input from the brake operating means 21. The distribution means for distributing the brakes and the individual brake control means for controlling the brakes 23 in accordance with the control commands for the distributed brakes 23 are collectively shown. When the brake is an electric brake and ABS control is possible, the ABS control performs the same control as the control shown in the control block diagram of FIG. In this case, however, the torque Ta input to the controller 17 and the output torque T are a torque command corresponding to the distributed braking force and a torque command obtained by processing the torque command.
Also in this case, since the vehicle speed V calculated by the vehicle speed estimation device 10 according to the embodiment is used for the calculation of the slip ratio, the vehicle speed can be accurately estimated not only when traveling straight but also when turning, and the ABS control is appropriately performed. Can be done.

  As mentioned above, although the form for implementing this invention based on the Example was demonstrated, embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 ... Vehicle 2 ... Wheel 3 ... ECU
4 ... Attitude sensor 5 ... Travel drive device (in-wheel motor drive device)
6 ... Each wheel vehicle speed equivalent amount calculation means 7 ... Vehicle speed change amount calculation means 8 ... Vehicle speed estimation means 9 ... Rotation angle sensor (rotation sensor)
12 ... Traction control means 13 ... ABS control means 18 ... Inverter device 25 ... Motor α _x '... First vehicle speed change amount V _i ... Vehicle speed equivalent amount γ ... Yaw angular velocity δ ... Threshold value

Claims (5)

An apparatus for estimating a vehicle speed in a four-wheel drive vehicle,
Each wheel vehicle speed equivalent amount calculating means for calculating a vehicle speed equivalent amount that is a speed corresponding to the vehicle speed from the rotational speed of each wheel using the yaw angular velocity of the vehicle acquired from the sensor;
According to the sign of the longitudinal acceleration of the vehicle acquired from the sensor or another sensor, the vehicle speed change amount per unit time of the vehicle speed equivalent amount that becomes the minimum value of the vehicle speed equivalent amount of the wheels during acceleration, First vehicle speed change amount calculating means for obtaining a first vehicle speed change amount that is a vehicle speed change amount per unit time of the vehicle speed equivalent amount that is the maximum value of the vehicle speed equivalent amount of each wheel during deceleration;
The absolute value of the difference between the second vehicle speed change amount and the first vehicle speed change amount, which is the acceleration in the vehicle longitudinal direction obtained from any one of the sensors or other sensors, is compared with a threshold value. The minimum value of the vehicle speed equivalent amount is determined as the vehicle speed when the longitudinal acceleration of the vehicle is accelerated, and the maximum value is determined as the vehicle speed when the vehicle is decelerated, and the absolute value of the difference is equal to or greater than the threshold value. In this case, vehicle speed estimation means for integrating the second vehicle speed change amount to obtain the vehicle speed,
A vehicle speed estimation device for a four-wheel drive vehicle.   2. The vehicle speed estimation device for a four-wheel drive vehicle according to claim 1, wherein the yaw angular velocity and the longitudinal acceleration of the vehicle are acquired from an attitude sensor, and the rotation speed of the wheel is determined from a rotation sensor of a wheel provided on each wheel. A vehicle speed estimation device for a four-wheel drive vehicle to be acquired.   The vehicle speed estimation device for a four-wheel drive vehicle according to claim 1 or 2, wherein the traveling drive means for driving each wheel of the vehicle is an in-wheel motor drive device. .   A vehicle speed estimation device for a four-wheel drive vehicle according to any one of claims 1 to 3, and a traction control means for performing traction control using the vehicle speed estimated by the vehicle speed estimation device. A vehicle drive control device for controlling a vehicle travel drive means.   A vehicle speed estimation device for a four-wheel drive vehicle according to any one of claims 1 to 3, and an ABS control means for performing ABS control using the vehicle speed estimated by the vehicle speed estimation device. A vehicle drive control device for controlling a vehicle.

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