KR20210035939A - Apparatus for controlling in wheel traction of in wheel hybird vehicle and method thereof - Google Patents

Abstract

Disclosed are an in-wheel traction control apparatus for an in-wheel hybrid vehicle, and a method thereof. According to the present invention, the in-wheel traction control apparatus for an in-wheel hybrid vehicle comprises: a wheel speed sensing unit for measuring a wheel speed at each wheel; a vehicle speed sensing unit detecting a vehicle speed of the vehicle; a control unit configured to receive the wheel speed and vehicle speed of each wheel from the wheel speed sensing unit and the vehicle speed sensing unit, determine a slip state, calculate a target wheel slip rate, and adjust a driving torque of an in-wheel motor based on the target wheel slip rate; and an in-wheel driving unit for driving the in-wheel motor based on the driving torque adjusted from the control unit.

Description

In-wheel traction control device of in-wheel hybrid vehicle and its method {APPARATUS FOR CONTROLLING IN WHEEL TRACTION OF IN WHEEL HYBIRD VEHICLE AND METHOD THEREOF}

The present invention relates to an in-wheel traction control apparatus and method for an in-wheel hybrid vehicle, and more specifically, traction based on the difference between the slip state of each wheel and a target slip value in a hybrid vehicle equipped with an in-wheel motor inside the front wheel. The present invention relates to an in-wheel traction control apparatus and method for an in-wheel hybrid vehicle capable of securing acceleration stability in a driving slip situation of a vehicle by reducing a slip rate by performing control.

In general, an in-wheel system is a system in which an in-wheel motor is mounted in the wheel of each wheel of a vehicle and each wheel can be controlled by independent driving. The drive system is simple, and thus space utilization is excellent.

In addition, since each wheel can be controlled by independent driving, the torque for each wheel can be adjusted, thereby improving the behavioral performance of the vehicle.

Hybrid vehicle refers to driving a vehicle by efficiently combining two or more different types of power sources, but in most cases, it is used in engines that obtain rotational power by burning fuel (fossil fuels such as gasoline) and electric motors that obtain rotational power by battery power. It means a vehicle driven by.

These hybrid vehicles are future vehicles that can reduce exhaust gas and improve fuel economy by adopting an electric motor as an auxiliary power source, as well as an engine, and more active research in response to the demands of the times to improve fuel economy and develop eco-friendly products. Is in progress.

On the other hand, as a device for improving the stability during driving of the vehicle, the ABS (Anti-lock Brake System) for preventing slip during braking, the TCS (Traction Control System) for preventing slip during sudden start, and the vehicle attitude during driving of the vehicle It is using ESC (Electronic Stability Control), a stability system that improves driving stability by maintaining stability.

The background technology of the present invention is disclosed in Korean Patent Application Publication No. 2012-0122599 (published on November 7, 2012, vehicle and its control method).

Conventional TCS uses ESC to apply hydraulic brake torque to the wheel when the drive wheel slips on a slippery road surface as each wheel operates individually. By doing so, it is possible to prevent the wheel slip of the wheel.

However, in the conventional TCS, since it takes a constant time to generate hydraulic pressure to apply the brake torque, relatively large lags and delays occur. Accordingly, the TCS can operate only after the wheel slip has already progressed to a considerable level. There was a disadvantage in that the wheel slip could not be effectively controlled. In short, since the TCS operates after the wheel slip of each wheel has occurred and the wheel slip has progressed to a considerable level, there is a disadvantage that it is difficult to effectively control the wheel slip for the corresponding wheel.

The present invention was conceived to improve the above problems, and an object of the present invention according to one aspect is based on the difference between the slip state of each wheel and the target slip value in a hybrid vehicle equipped with an in-wheel motor inside the front wheel. It is to provide an in-wheel traction control apparatus and method for an in-wheel hybrid vehicle capable of securing acceleration stability in a driving slip situation of a vehicle by reducing the slip rate by performing traction control.

In-wheel traction control apparatus of an in-wheel hybrid vehicle according to an aspect of the present invention,

A wheel speed sensing unit that measures the wheel speed at each wheel; A vehicle speed detection unit that detects a vehicle speed of the vehicle; A control unit for calculating a target wheel slip rate by receiving the wheel speed and vehicle speed of each wheel of the wheel speed detection unit and the vehicle speed detection unit rotor, determining a slip state, and adjusting a driving torque of the in-wheel motor based on the target wheel slip rate; And an in-wheel drive unit for driving the in-wheel motor based on the driving torque adjusted by the control unit.

In the present invention, the in-wheel hybrid vehicle is characterized in that it is a four-wheel drive vehicle in which an in-wheel motor is mounted on a front wheel of a rear-wheel drive vehicle.

In the present invention, the control unit is characterized in that it determines the slip state based on the difference between the wheel speed of each wheel and the vehicle speed.

The present invention further includes a motor RPM detection unit for detecting the RPM of the in-wheel motor, wherein the control unit determines the soundness of the wheel speed by comparing the wheel speed with the RPM of the in-wheel motor.

In the present invention, the control unit is characterized in that it calculates a target wheel slip rate based on a difference between the estimated vehicle speed and the vehicle speed.

In the present invention, the control unit is characterized in that it adjusts the driving torque by performing PI control.

In the present invention, the control unit is characterized in that when the slip rate decreases while reducing the driving torque, the driving torque is maintained and then the driving torque is gradually increased while adjusting the driving torque.

In another aspect of the present invention, a method for controlling in-wheel traction of an in-wheel hybrid vehicle includes the steps of: receiving, by a controller, a wheel speed and a vehicle speed of each wheel from a wheel speed detection unit and a vehicle speed detection unit; Determining, by the controller, a slip state of each wheel based on the wheel speed and the vehicle speed of each wheel; Determining, by the controller, a slip state of each wheel and calculating a target wheel slip rate; And adjusting, by the control unit, a driving torque of the in-wheel motor based on the target wheel slip rate.

In the present invention, the in-wheel hybrid vehicle is characterized in that it is a four-wheel drive vehicle in which an in-wheel motor is mounted on a front wheel of a rear-wheel drive vehicle.

In the present invention, the step of determining the slip state is characterized in that the control unit determines the slip state of each wheel based on a difference between the wheel speed of the wheel and the vehicle speed.

In the present invention, the step of determining the slip state may further include the step of determining, by the control unit, the soundness of the wheel speed by receiving the RPM of the in-wheel motor from the motor RPM detection unit and comparing it with the wheel speed.

In the present invention, the step of calculating the target wheel slip rate is characterized in that the target wheel slip rate is calculated based on a difference between the estimated vehicle speed and the vehicle speed.

In the present invention, the step of adjusting the driving torque of the in-wheel motor is characterized in that the control unit performs PI control to adjust the driving torque.

In the present invention, the step of adjusting the driving torque of the in-wheel motor is characterized in that the control unit adjusts the driving torque while gradually increasing the driving torque after maintaining the driving torque when the slip rate decreases while reducing the driving torque. .

The in-wheel traction control apparatus and method of an in-wheel hybrid vehicle according to an aspect of the present invention perform traction control based on a difference between a slip state of each wheel and a target slip value in a hybrid vehicle equipped with an in-wheel motor inside the front wheel. Accordingly, it is possible to reduce the slip rate and secure acceleration stability in a driving slip situation of the vehicle.

1 is a block diagram showing an in-wheel traction control apparatus of an in-wheel hybrid vehicle according to an embodiment of the present invention.
2 is a graph comparing in-wheel traction control states of an in-wheel hybrid vehicle according to an embodiment of the present invention.
3 is a flowchart illustrating an in-wheel traction control method of an in-wheel hybrid vehicle according to an embodiment of the present invention.

Hereinafter, an in-wheel traction control apparatus and method for an in-wheel hybrid vehicle according to the present invention will be described with reference to the accompanying drawings. In this process, the thickness of the lines or the size of components shown in the drawings may be exaggerated for clarity and convenience of description. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of users or operators. Therefore, definitions of these terms should be made based on the contents throughout the present specification.

1 is a block diagram showing an in-wheel traction control apparatus of an in-wheel hybrid vehicle according to an embodiment of the present invention, and FIG. 2 is a graph comparing in-wheel traction control states of an in-wheel hybrid vehicle according to an embodiment of the present invention. .

As shown in FIG. 1, the in-wheel traction control apparatus of an in-wheel hybrid vehicle according to an embodiment of the present invention includes a wheel speed detection unit 10, a vehicle speed detection unit 20, a control unit 30, and an in-wheel drive unit 40. It characterized in that it comprises a.

In this embodiment, the in-wheel hybrid vehicle controls the wheel speed by adjusting the drive torque and the regenerative torque using the responsiveness and accuracy of the in-wheel motor 50 in a four-wheel drive vehicle in which the in-wheel motor 50 is mounted on the front wheel of the rear-wheel drive vehicle. It is to do.

The wheel speed detection unit 10 may measure the wheel speed at each wheel and provide it to the control unit 30.

The motor RPM detection unit 15 may detect the RPM of the in-wheel motor 50 and provide it to the control unit 30.

The vehicle speed detection unit 20 may detect the vehicle speed of the vehicle and provide it to the control unit 30.

The control unit 30 calculates a target wheel slip rate by receiving the wheel speed and vehicle speed of each wheel of the rotor with the wheel speed detection unit 10 and the vehicle speed detection unit 20, and calculates a target wheel slip rate based on the target wheel slip rate. Traction control may be performed by adjusting the driving torque of the in-wheel motor 50.

Here, the controller 30 may determine a slip state by calculating a slip ratio of each wheel, which is a difference between the wheel speed of each wheel and the vehicle speed.

On the other hand, when the control unit 30 receives the RPM of the in-wheel motor 50 from the motor RPM detection unit 15, it is possible to determine the soundness of the wheel speed by comparing it with the wheel speed input from the wheel speed detection unit 10. In addition, it is also possible to determine the slip state based on the RPM of the in-wheel motor 50.

In addition, a target wheel slip rate may be calculated based on a difference between the estimated vehicle speed and the vehicle speed, compared with the slip rate of each wheel, and traction control may be performed when the set value is exceeded.

That is, the controller 30 may adjust the actual wheel speed by adjusting the driving torque and the regenerative torque of the in-wheel motor 50 through PI control.

In this case, when the slip rate is reduced while reducing the driving torque, the controller 30 may perform traction control so that the vehicle is towed while maintaining the driving torque and gradually increasing the driving torque.

The in-wheel drive unit 40 may control the slip by driving the in-wheel motor 50 based on the driving torque and the regenerative torque adjusted by the control unit 30 to tow the vehicle.

As shown in Fig. 2, a state in which traction control is not performed (①) and a state in which traction control is performed (②) in a state in which a driving slip situation is generated by stepping on the accelerator pedal to the maximum at low friction. In comparison, in terms of acceleration stability, the maximum vehicle speed was about 45 km/h, and the road surface escape time was about 20 seconds apart. It can be seen that the driving slip rate has also been reduced.

Even in the low-friction road climbing performance, it has succeeded in climbing on a 15% inclined road surface, and through the responsiveness of the in-wheel motor 50 of the front wheel, the front wheel first secures the frictional force of the wheel, and thus the vehicle can be towed.

As described above, according to the in-wheel traction control apparatus of the in-wheel hybrid vehicle according to the embodiment of the present invention, the in-wheel traction control apparatus of the in-wheel hybrid vehicle and the method thereof are By performing traction control based on the difference between the slip state and the target slip value, the slip rate can be reduced, so that acceleration stability can be secured in the driving slip situation of the vehicle.

3 is a flowchart illustrating an in-wheel traction control method of an in-wheel hybrid vehicle according to an embodiment of the present invention.

3, in the in-wheel traction control method of an in-wheel hybrid vehicle according to an embodiment of the present invention, first, the control unit 30 uses the wheel speed detection unit 10 and the vehicle speed detection unit 20 to determine the wheels of each wheel. The speed and vehicle speed are inputted (S10).

In this embodiment, the in-wheel hybrid vehicle performs traction control by adjusting the driving torque and the regenerative torque using the responsiveness and accuracy of the in-wheel motor 50 in a four-wheel drive vehicle in which the in-wheel motor 50 is mounted on the front wheel of the rear-wheel drive vehicle. This explains how to control the wheel speed.

After receiving the wheel speed and vehicle speed of each wheel in step S10, the controller 30 determines the slip state of each wheel (S20).

Here, the controller 30 may determine a slip state by calculating a slip ratio of each wheel, which is a difference between the wheel speed of each wheel and the vehicle speed.

On the other hand, when the control unit 30 receives the RPM of the in-wheel motor 50 from the motor RPM detection unit 15, it is possible to determine the soundness of the wheel speed by comparing it with the wheel speed input from the wheel speed detection unit 10. In addition, it is also possible to determine the slip state based on the RPM of the in-wheel motor 50.

When the slip state is determined in step S10 and the slip state is not determined, it ends, and when the slip state is determined, the control unit 30 calculates a target wheel slip rate based on the difference between the estimated vehicle speed and the vehicle speed (S30).

After calculating the target wheel slip rate in step S30, the controller 30 compares the target wheel slip rate with the actual wheel slip rate (S40).

When the difference between the target wheel slip rate and the actual wheel slip rate exceeds a set value by comparing the target wheel slip rate and the actual wheel slip rate in step S40, the controller 30 uses the in-wheel drive unit 40 to provide an in-wheel motor ( The traction control is performed to follow the target wheel slip rate by adjusting the driving torque and regenerative torque of 50) (S50).

Here, the control unit 30 may adjust the actual wheel speed by adjusting the driving torque and the regenerative torque of the in-wheel motor 50 through PI control.

In this case, when the slip rate is reduced while reducing the driving torque, the controller 30 may perform traction control so that the vehicle is towed while maintaining the driving torque and gradually increasing the driving torque.

Therefore, as shown in Fig. 2, due to the responsiveness of the in-wheel motor 50 of the front wheel during early rapid acceleration in a low friction road, the driving slip rate of the rear wheel can be reduced to secure optimal acceleration performance, and the slope of the low friction road In terms of performance, the front wheel can first secure the frictional force of the wheel through the responsiveness of the in-wheel motor 50 of the front wheel to pull the vehicle, thereby climbing the mountain.

As described above, according to the in-wheel traction control method of the in-wheel hybrid vehicle according to the embodiment of the present invention, the in-wheel traction control apparatus of the in-wheel hybrid vehicle and the method thereof are By performing traction control based on the difference between the slip state and the target slip value, the slip rate can be reduced, so that acceleration stability can be secured in the driving slip situation of the vehicle.

The implementation described herein may be implemented in, for example, a method or process, an apparatus, a software program, a data stream or a signal. Although discussed only in the context of a single form of implementation (eg, only as a method), the implementation of the discussed features may also be implemented in other forms (eg, an apparatus or program). The device may be implemented with appropriate hardware, software and firmware. The method may be implemented in an apparatus such as a processor, which generally refers to a processing device including, for example, a computer, a microprocessor, an integrated circuit or a programmable logic device, or the like. Processors also include communication devices such as computers, cell phones, personal digital assistants ("PDAs") and other devices that facilitate communication of information between end-users.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is only illustrative, and those of ordinary skill in the field to which the technology pertains, various modifications and other equivalent embodiments are possible. I will understand.

Therefore, the true technical protection scope of the present invention should be determined by the following claims.

10: wheel speed detection unit
15: motor RPM detection unit
20: vehicle speed detection unit
30: control unit
40: in-wheel drive
50: in-wheel motor

Claims (14)

A wheel speed sensing unit that measures the wheel speed at each wheel;
A vehicle speed detector for detecting a vehicle speed of the vehicle;
The wheel speed detection unit and the vehicle speed detection unit receive the wheel speed and the vehicle speed of each wheel of the rotor, determine a slip state, calculate a target wheel slip rate, and calculate the driving torque of the in-wheel motor based on the target wheel slip rate. A control unit to adjust; And
And an in-wheel drive unit for driving the in-wheel motor based on a driving torque adjusted by the control unit.
The in-wheel traction control apparatus according to claim 1, wherein the in-wheel hybrid vehicle is a constant four-wheel drive vehicle in which the in-wheel motor is mounted on a front wheel of a rear-wheel drive vehicle.
The in-wheel traction control apparatus of claim 1, wherein the control unit determines the slip state based on a difference between the wheel speed of each wheel and the vehicle speed.
The method of claim 1, further comprising a motor RPM detection unit configured to detect RPM of the in-wheel motor, wherein the control unit determines soundness of the wheel speed by comparing the wheel speed with the RPM of the in-wheel motor. In-wheel traction control device for in-wheel hybrid vehicle.
The in-wheel traction control apparatus of claim 1, wherein the control unit calculates the target wheel slip rate based on a difference between the estimated vehicle speed and the vehicle speed.
The in-wheel traction control apparatus of claim 1, wherein the control unit adjusts the driving torque by performing PI control.
The in-wheel hybrid according to claim 1, wherein the control unit adjusts the driving torque while gradually increasing the driving torque after maintaining the driving torque when the slip rate decreases while reducing the driving torque. Vehicle in-wheel traction control.
Receiving, by the control unit, the wheel speed and vehicle speed of each wheel from the wheel speed detection unit and the vehicle speed detection unit;
Determining, by the control unit, a slip state of each wheel based on the wheel speed and the vehicle speed of each wheel;
Calculating, by the control unit, a target wheel slip rate by determining the slip state of each wheel; And
And adjusting, by the control unit, the driving torque of the in-wheel motor based on the target wheel slip rate.
9. The method of claim 8, wherein the in-wheel hybrid vehicle is a constant four-wheel drive vehicle in which the in-wheel motor is mounted on a front wheel of a rear-wheel drive vehicle.
The in-wheel traction control of an in-wheel hybrid vehicle according to claim 8, wherein the determining of the slip state comprises determining, by the controller, the slip state of each wheel based on a difference between the wheel speed and the vehicle speed. Way.
The method of claim 8, wherein the determining of the slip state further comprises: receiving, by the control unit, an RPM of the in-wheel motor from a motor RPM detection unit and comparing it with the wheel speed to determine soundness of the wheel speed In-wheel traction control method of an in-wheel hybrid vehicle, characterized in that.
The method of claim 8, wherein the calculating of the target wheel slip rate comprises calculating the target wheel slip rate based on a difference between the estimated vehicle speed and the vehicle speed.
The method of claim 8, wherein the adjusting of the driving torque of the in-wheel motor comprises adjusting the driving torque by performing PI control by the control unit.
The method of claim 8, wherein the adjusting of the driving torque of the in-wheel motor comprises: when the slip rate decreases while the control unit reduces the driving torque, the driving torque is gradually increased after maintaining the driving torque. In-wheel traction control method of an in-wheel hybrid vehicle, characterized in that adjusting the driving torque.

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