JP2011130628A - Controller for right-left drive force adjusting device for vehicle - Google Patents

Abstract

The present invention provides a control device for a vehicle left / right driving force adjusting device that performs control according to a control law by eliminating the influence of a torque difference generated by an inertia moment.
When the rotation speed of a motor 16 is N _m , the rotation speed difference between the left and right wheels is ΔN, the moment of inertia of the motor 16 is I, and the reduction ratio G of the motor 16 is [N _m / ΔN], the rotation speed difference The torque difference correction value [2G ² · I · dΔN] is obtained by integrating G ² which is the square of the moment of inertia I and the reduction ratio G to the rotational speed difference angular acceleration dΔN obtained by differentiating ΔN. From the control laws 1 to M, a control output corresponding to the torque difference is obtained, a correction value is added to the control output, a correction torque difference is obtained, and the motor 16 is controlled so as to obtain the obtained correction torque difference. Perform vehicle attitude control.
[Selection] Figure 2

Description

  The present invention relates to a control device for a left / right driving force adjusting device for a vehicle.

  2. Description of the Related Art Conventionally, a vehicle left / right driving force adjusting device that adjusts driving force of left and right wheels of a vehicle is known. The vehicle left / right driving force adjusting device includes, for example, a differential gear 14 having a prime mover 11 connected between a left wheel 12 and a right wheel 13 and a driving force adjusting mechanism 15 as shown in FIG. is doing. As one of the driving force adjusting mechanisms 15, as shown in FIG. 1, an electric active yaw control (hereinafter referred to as electric AYC) having an electric motor 16 and a gear mechanism 17 is known. Control device 20 controls electric motor 16 to adjust the distribution of driving force to left wheel 12 and right wheel 13.

Japanese Patent No. 3686626 JP 2006-046495 A JP 2006-057745 A JP 2003-335143 A

In the electric AYC, the motor rotation speed N _m is proportional to the reduction ratio G and the rotation speed difference ΔN between the left and right wheels, and can be expressed by the following equation (1).
N _m = G · ΔN (1)
Further, when the torque difference between the left and right wheels and a [Delta] T, the torque movement amount [Delta] T / 2 to each of the right wheel and the left wheel is proportional to the reduction ratio G and the motor torque T _m, be represented by the following formula (2) Can do.
ΔT / 2 = G · T _m (2)
Further, in order for the motor having the moment of inertia I to rotate at the angular acceleration dN _m (differential value of N _m ), the torque represented by the following formula (3) is required.
τ _LOAD = I · dN _m = I · G · dΔN (3)
Here, dΔN is an angular acceleration of a difference in rotational speed between the left and right wheels, and is a differential value of ΔN.
Therefore, the torque τ _LOAD represented by the equation (3) acts on the vehicle as the torque difference ΔT _LOAD represented by the following equation (4) or (5) from the equation (2).
ΔT _LOAD = 2G ・ τ _LOAD
= 2G · (I · G · dΔN)
= 2G ² · I · dΔN (4)
Or ΔT _LOAD = 2G · τ _LOAD
= 2G · (I · dN _m )
= 2G · I · dN _m (5)

As the characteristics of the electric AYC, as expressed by the equation (4), the torque difference ΔT _LOAD proportional to the angular moment of inertia I, the square of the reduction ratio G, and the angular acceleration dΔN of the difference between the rotational speeds of the left and right wheels, or As represented by 5), a torque difference ΔT _LOAD proportional to the moment of inertia I, the reduction ratio G, and the angular acceleration dN _m of the motor rotation speed acts on the vehicle. This means that the moment of inertia I of the motor itself affects the attitude control of the vehicle. In particular, when the reduction ratio G is increased in order to amplify the motor torque, the torque difference ΔT _LOAD becomes a large value that affects the vehicle motion.

  Therefore, when the vehicle attitude control is performed due to the influence of the torque difference generated by the inertia moment I of the motor itself, a torque difference different from the value calculated by the control law is generated and the control is performed. Even when there is not, there is a possibility that an unintended torque difference occurs and the desired posture control cannot be performed.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a control device for a left / right driving force adjusting device for a vehicle that performs control according to a control law while eliminating the influence of a torque difference caused by a moment of inertia. To do.

A control device for a left / right driving force adjusting device for a vehicle according to a first aspect of the present invention for solving the above-described problem is provided.
A left and right driving force adjusting device for a vehicle that has a motor that generates a torque difference between the left and right wheels of the vehicle, and controls the attitude of the vehicle using the motor;
A control device for controlling the motor,
The controller is
When the rotational speed of the motor is N _m , the rotational speed difference between the left and right wheels is ΔN, the moment of inertia of the motor is I, and the reduction ratio G of the motor is [N _m / ΔN],
The torque difference correction value [2G ² · I · dΔN] is obtained by accumulating G ² which is the square of the inertia moment I and the reduction ratio G to the rotational speed difference angular acceleration dΔN obtained by differentiating the rotational speed difference ΔN. ]
Obtaining a control output corresponding to the torque difference by at least one known control law;
Add the correction value to the control output to obtain a correction torque difference,
The attitude of the vehicle is controlled by controlling the motor so that the correction torque difference is obtained.

A control device for a vehicle left-right driving force adjusting device according to a second invention for solving the above-described problems
A left and right driving force adjusting device for a vehicle that has a motor that generates a torque difference between the left and right wheels of the vehicle, and controls the attitude of the vehicle using the motor;
A control device for controlling the motor,
The controller is
When the rotational speed of the motor is N _m , the rotational speed difference between the left and right wheels is ΔN, the moment of inertia of the motor is I, and the reduction ratio G of the motor is [N _m / ΔN],
The motor angular acceleration dN _m obtained by differentiating the rotational speed N _m is integrated with the moment of inertia I and the reduction ratio G to obtain a correction value [2G · I · dN _m ] for the torque difference,
Obtaining a control output corresponding to the torque difference by at least one known control law;
Add the correction value to the control output to obtain a correction torque difference,
The attitude of the vehicle is controlled by controlling the motor so that the correction torque difference is obtained.

  According to the present invention, the torque difference is corrected in accordance with the rotational speed difference angular acceleration or the motor angular acceleration, thereby eliminating the influence of the torque difference caused by the moment of inertia of the motor, and the control law. It is possible to perform control as calculated by.

  In addition, when correcting the torque difference using the motor angular acceleration, it is possible to obtain the motor angular acceleration with higher accuracy than when correcting the torque difference using the rotational speed difference angular acceleration. The control accuracy is also higher.

It is a schematic structure figure explaining an example of an embodiment of a control device of a right-and-left driving force adjustment device for vehicles concerning the present invention. It is a block diagram explaining the control apparatus shown in FIG. It is a block diagram explaining the modification of the control apparatus shown in FIG.

  Hereinafter, with reference to FIG. 1 to FIG. 3, an example of an embodiment of a control device for a vehicle left-right driving force adjusting device according to the present invention will be described.

Example 1
FIG. 1 is a schematic configuration diagram illustrating a control device for a left / right driving force adjusting device for a vehicle according to the present embodiment. FIG. 2 is a block diagram for explaining the control device shown in FIG. 1, and FIG. 3 is a block diagram for explaining a modification of the control device shown in FIG.

  As shown in FIG. 1, the vehicle left / right driving force adjusting device transmits an output from a prime mover 11 such as an engine or a motor to the left wheel 12 and the right wheel 13 as a driving force, and rotates the left wheel 12 and the right wheel 13. A differential gear 14 that adjusts the number difference and a driving force adjusting mechanism 15 that adjusts the distribution of the driving force to the left wheel 12 and the right wheel 13 are provided between the left wheel 12 and the right wheel 13. The driving force adjusting mechanism 15 includes an electric motor 16 and a gear mechanism 17 that generate a torque difference between the left wheel 12 and the right wheel 13 by output torque. The electric motor 16 is an ECU (control device) 20. Controlled by This is a so-called electric AYC, which functions as an actuator that generates a yaw moment for controlling the attitude of the vehicle. By controlling the electric motor 16 by the ECU 20, the left and right wheels 12 and 13 are connected to the right wheel 13. The distribution of driving force is adjusted.

  Note that, for example, a bevel gear type is used as the differential gear 14, but the configuration of the differential gear 14 is not directly related to the present invention, and a detailed description thereof will be omitted.

  The gear mechanism 17 adjusts the distribution amount of the driving force transmitted to the left wheel 12 and the right wheel 13 together with the electric motor 16, but the configuration itself of the gear mechanism 17 is also directly related to the present invention. Since it is not a part to do, the detailed description is abbreviate | omitted.

  The left wheel 12 and the right wheel 13 to be controlled may be front wheels only, rear wheels only, or all four wheels, but in this embodiment, the description will be made assuming that the control objects are only rear wheels.

  Next, the function and control of the ECU 20 will be described with reference to FIG. 2 (FIG. 3). Here, the counterclockwise direction is a positive sign of the yaw rate and yaw moment, and the left-right wheel rotation speed difference and the motor rotation direction when turning counterclockwise in the grip state are positive signs.

The ECU 20 includes a plurality of control laws _{1 to M} for obtaining a torque difference, a calculator C1 that calculates the sum of the torque differences ΔT _{1 to} ΔTM obtained by the control laws _{1 to M} as a control output, and a correction value. , A computing unit C2 for integrating the rotational speed difference angular acceleration and [2G ² · I], and a computing unit C3 for adding a correction value from the computing unit C2 to the control output from the computing unit C1 to obtain a corrected torque difference. And motor control for controlling the electric motor 16 so that the motor output torque is converted to the torque difference → motor output torque conversion means B1 converted to the motor output torque based on the correction torque difference obtained by the calculator C3. Means B2.

Here, the speed reduction ratio G is expressed by G = N _m / ΔN using the motor rotation speed N _m and the rotation speed difference ΔN between the left and right wheels, as can be seen from the equation (1). The inertia moment I is unique to the electric motor 16.

  The control laws 1 to M may be known control laws such as yaw rate feedback control, target rotational speed difference tracking control, and drive torque feedforward control. For example, the yaw rate feedback control performs PD control of the difference between the target yaw rate calculated from the vehicle speed and the steering angle and the actual yaw rate. Further, the target rotational speed difference follow-up control performs PD control of the difference between the target left and right wheel rotational speed difference calculated from the vehicle speed and the steering angle and the actual left and right wheel rotational speed difference. In addition, the drive torque feedforward control performs feedforward control according to the increase in drive torque and steering angle. Note that the events corresponding to the control laws 1 to M are independent of each other.

なお、ここでは、最適な制御出力を演算するために、単純に、複数のトルク差ΔＴ₁〜ΔＴ_Mの総和を演算したが、例えば、複数のトルク差ΔＴ₁〜ΔＴ_Mの中から最適な１つを選択し、選択したものを制御出力としてもよいし、複数のトルク差ΔＴ₁〜ΔＴ_Mを用いて、確率論的モデルにより、最適な制御出力を求めるようにしてもよい。 The computing unit C1 uses the torque differences ΔT _{1 to} ΔT _M obtained by a plurality of control laws _{1 to M} to obtain a control output by the following equation.

Here, in order to calculate the optimum control output, the sum total of a plurality of torque differences ΔT _{1 to} ΔT _M is simply calculated. However, for example, the optimum among the plurality of torque differences ΔT _{1 to} ΔT _M is calculated. One may be selected, and the selected one may be used as a control output, or an optimal control output may be obtained by a probabilistic model using a plurality of torque differences ΔT _{1 to} ΔT _M.

The rotational speed difference angular acceleration used in the computing unit C2 detects the right rear wheel rotational speed and the left rear wheel rotational speed using a wheel speed sensor provided in each wheel, and detects the detected right rear wheel rotational speed and the left rear rotational speed. Based on the wheel rotational speed and the conversion coefficient K _R for converting the rotational speed to radians, the rotational speed difference angular acceleration is obtained by the following equation.
Speed difference angular acceleration = differential [(right rear wheel speed−left rear wheel speed) × K _R ] (7)
Then, the correction value for the torque difference is obtained by adding G ² that is the square of the inertia moment I and the reduction ratio G to the obtained rotational speed difference angular acceleration according to the following equation.
Correction value = (Rotational speed difference angular acceleration) · 2G ² · I (8)
This correction value is a torque difference generated by the inertia moment I inherent in the electric motor 16, and this is used as a correction value to eliminate the influence of the inertia moment I of the electric motor 16.

Instead of the above-described computing unit C2, as shown in FIG. 3, a computing unit C4 that integrates motor angular acceleration and [2G · I] to obtain a correction value may be used. In this case, based on the rotation speed of the electric motor 16 and the conversion coefficient K _R , the motor angular acceleration is obtained by the following equation.
Motor angular acceleration = differential [(motor rotational speed) × K _R ] (9)
Then, the correction value for the torque difference is obtained by adding the moment of inertia I and the reduction ratio G to the obtained motor angular acceleration according to the following equation.
Correction value = (motor angular acceleration) · 2G · I (10)
This correction value is a torque difference generated by the inertia moment I inherent in the electric motor 16, and this is used as a correction value to eliminate the influence of the inertia moment I of the electric motor 16. 3 is different from the ECU 20 shown in FIG. 2 only in the correction value calculation part.

Further, the torque difference → motor output torque conversion means B1 uses the conversion coefficient = 1 / (2G) based on the above equation (2) and the corrected torque difference obtained by the calculator C3 to calculate the motor output by the following equation. Convert to torque.
Motor output torque = corrected torque difference × (1 / (2G)) (11)

  Here, with reference to FIG.2 and FIG.3, a series of control procedures in ECU20 are demonstrated.

Torque differences ΔT _{1 to} ΔT _M are obtained by a plurality of control laws _{1 to M, and} a total sum of the plurality of torque differences ΔT _{1 to} ΔT _M is obtained by the calculator C1 using the above equation (6).

The calculator C2, by using equation (8), the rotational speed difference angular acceleration determined by measurement and calculation, by integrating G ² is the square of the moment of inertia I and the reduction ratio G, the correction value of the torque difference Ask for. Or, instead of the calculator C2, the calculator C4 adds the moment of inertia I and the reduction ratio G to the motor angular acceleration obtained by measurement and calculation using the above equation (10) to correct the torque difference. Find the value.

  The arithmetic unit C3 adds the correction value obtained by the arithmetic unit C2 or the arithmetic unit C4 to the control output obtained by the arithmetic unit C1, thereby obtaining a correction torque difference.

  Then, the torque difference → motor output torque conversion means B1 converts the correction torque difference obtained by the calculator C3 into the motor output torque using the above equation (11).

  Then, the electric motor 16 is controlled by the motor control means B2 so that the converted motor output torque is obtained.

  With the control described above, the torque difference is corrected according to the rotational speed difference angular acceleration or the motor angular acceleration, thereby eliminating the influence of the torque difference generated by the inertia moment I of the electric motor 16, Control as calculated by the control law can be performed. In particular, when correcting the torque difference using the motor angular acceleration, the motor rotational speed is G times the reduction ratio of the left and right wheel rotational speed difference, so the rotational speed difference angular acceleration is used to correct the torque difference. It is possible to obtain the motor angular acceleration with higher accuracy than in the case of performing the above, and the control accuracy becomes higher.

  The present invention is suitable for a control device for a left / right driving force adjusting device for a vehicle that uses an electric motor to adjust the driving force of the left / right wheels of the vehicle.

11 prime mover 12 left wheel 13 right wheel 14 differential gear 15 driving force adjustment mechanism 16 electric motor 17 gear mechanism 20 ECU

Claims (2)

A left and right driving force adjusting device for a vehicle that has a motor that generates a torque difference between the left and right wheels of the vehicle, and controls the attitude of the vehicle using the motor;
A control device for controlling the motor,
The controller is
When the rotational speed of the motor is N _m , the rotational speed difference between the left and right wheels is ΔN, the moment of inertia of the motor is I, and the reduction ratio G of the motor is [N _m / ΔN],
The torque difference correction value [2G ² · I · dΔN] is obtained by accumulating G ² which is the square of the inertia moment I and the reduction ratio G to the rotational speed difference angular acceleration dΔN obtained by differentiating the rotational speed difference ΔN. ]
Obtaining a control output corresponding to the torque difference by at least one known control law;
Add the correction value to the control output to obtain a correction torque difference,
A control device for a vehicle left-right driving force adjustment device, wherein the motor is controlled to control the attitude of the vehicle so that the correction torque difference is obtained. A left and right driving force adjusting device for a vehicle that has a motor that generates a torque difference between the left and right wheels of the vehicle, and controls the attitude of the vehicle using the motor;
A control device for controlling the motor,
The controller is
When the rotational speed of the motor is N _m , the rotational speed difference between the left and right wheels is ΔN, the moment of inertia of the motor is I, and the reduction ratio G of the motor is [N _m / ΔN],
The motor angular acceleration dN _m obtained by differentiating the rotational speed N _m is integrated with the moment of inertia I and the reduction ratio G to obtain a correction value [2G · I · dN _m ] for the torque difference,
Obtaining a control output corresponding to the torque difference by at least one known control law;
Add the correction value to the control output to obtain a correction torque difference,
A control device for a vehicle left-right driving force adjustment device, wherein the motor is controlled to control the attitude of the vehicle so that the correction torque difference is obtained.

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