KR20230152949A - Method and device for lateral control in costregen steering of vehicle - Google Patents

Abstract

Disclosed is a lateral control method and device for cost-regenerating steering of a vehicle.
The lateral control method includes receiving a request related to regenerative braking control; determining whether a slip ratio calculated based on the wheel speed satisfies a first entry condition; determining whether the yaw rate error between the required yaw rate and the actual yaw rate satisfies a second entry condition; In response to the slip rate and the error satisfying first and second entry conditions, respectively, applying stabilization torque as a motor torque of a motor driving the wheel; and applying a required torque according to the regenerative braking control to the motor torque in response to at least one of the slip rate and the error not satisfying first and second entry conditions.

Description

Lateral control method and device for costregen steering of a vehicle {METHOD AND DEVICE FOR LATERAL CONTROL IN COSTREGEN STEERING OF VEHICLE}

The present disclosure relates to a lateral control method and device for cost-regenerative steering of a vehicle, and more specifically, to a lateral control method and device for securing lateral stability of a vehicle during deceleration by regenerative braking control on a low-friction road. It is about.

Electric energy-based vehicles can utilize regenerative braking as a means of auxiliary braking. An electric energy-based vehicle may, for example, be a mobile vehicle that employs a directly charged electric battery or a hydrogen-based fuel cell as an energy source. With the user's regenerative braking operation, the vehicle can be slowed down without the user having to operate an active braking device such as a brake. However, it is necessary to control the regenerative braking torque to prevent the vehicle from slipping on a low friction road during deceleration according to regenerative braking control.

When controlling regenerative braking torque, control can be performed according to a target slip ratio that can secure maximum braking force. Braking force is maximum at an appropriate slip rate, but lateral force tends to decrease as the slip rate increases, and when lateral force is reduced, vehicle shaking increases and driving stability becomes unstable. In particular, when the slip rate is high, the user's rapid steering combined with low lateral force may cause the vehicle to lose stability and spin. In addition, rapid steering on low-friction roads, unevenness of the road surface, etc. cause the vehicle to sway left and right, and these fluctuations behave similarly to pendulum movements and do not disappear as long as regenerative braking continues.

Therefore, in situations where regenerative braking control is selected, there is a need for technology to ensure both longitudinal and lateral stability in low-friction road situations using only motor control without brake intervention.

The technical problem of the present disclosure is to provide a lateral control method and device for cost-regenerative steering of a vehicle to ensure lateral stability of the vehicle when decelerating by regenerative braking control on a low-friction road.

The technical problems to be achieved by this disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by those skilled in the art from the description below. You will be able to.

According to one aspect of the present disclosure, a method for controlling the lateral direction when cost-regenerating steering of a vehicle is provided. The lateral control method includes receiving a request related to regenerative braking control; determining whether a slip ratio calculated based on the wheel speed satisfies a first entry condition; determining whether the yaw rate error between the required yaw rate and the actual yaw rate satisfies a second entry condition; In response to the slip rate and the error satisfying first and second entry conditions, respectively, applying stabilization torque as a motor torque of a motor driving the wheel; and applying a required torque according to the regenerative braking control to the motor torque in response to at least one of the slip rate and the error not satisfying first and second entry conditions.

According to another embodiment of the present disclosure, the stabilization torque is a preset torque and may be zero torque.

According to another embodiment of the present disclosure, The first entry condition may be a condition in which the slip rate is equal to or greater than the critical slip rate.

According to another embodiment of the present disclosure, if the slip rate that entered above the threshold slip rate changes and the condition of continuing for more than the release threshold time below the release slip rate that is less than the threshold slip rate continues, the first entry The condition may further include a step of being released.

According to another embodiment of the present disclosure, the wheel includes front and rear wheels, and one of the front and rear wheels is a driving wheel, and the other wheel of the front and rear wheels is a driven wheel, When the speed of the driven wheel is faster than the driving wheel, the slip rate may be calculated as a ratio of the difference between the driven wheel speed and the driving wheel speed to the driven wheel speed.

According to another embodiment of the present disclosure, the driven wheel includes a driven left wheel and a driven right wheel, and the driving wheel includes a driven left wheel and a driven right wheel, and the slip rate is determined by the following: It may be calculated based on the maximum value of the left slip rate calculated based on the speeds of the driven left wheel and the right slip rate calculated based on the speeds of the driven right wheel and the driven right wheel.

According to another embodiment of the present disclosure, The required yaw rate may be calculated based on the vehicle's speed, wheel steering angle, and wheel base distance between the front and rear wheels.

According to another embodiment of the present disclosure, the second entry condition may be a condition in which the yaw rate error continues to exceed the reference error.

According to another embodiment of the present disclosure, the second entry condition may be a condition in which the yaw rate error greater than the reference error continues for more than the error threshold time.

According to another aspect of the present disclosure, a lateral control device for costrigen steering of a vehicle may be provided. The lateral control device includes a memory storing at least one instruction; and a processor executing the at least one instruction stored in the memory. The processor receives a request related to regenerative braking control, determines whether the slip rate calculated based on the wheel speed satisfies the first entry condition, and determines whether the yaw rate error between the required yaw rate and the actual yaw rate meets the second entry condition. is satisfied, and in response to the slip rate and the error satisfying the first and second entry conditions, respectively, applying stabilization torque as a motor torque of the motor driving the wheel, and among the slip rate and the error In response to the at least one not satisfying the first and second entry conditions, it is configured to apply the required torque according to the regenerative braking control to the motor torque.

The features briefly summarized above with respect to the present disclosure are merely exemplary aspects of the detailed description of the present disclosure described below, and do not limit the scope of the present disclosure.

According to the present disclosure, it is possible to provide a lateral control method and device for costrigen steering of a vehicle to ensure lateral stability of the vehicle when decelerating by regenerative braking control on a low friction road.

Specifically, it detects the vehicle's shaking or instability using the vehicle's yaw rate, steering angle, and slip rate as factors, and transmits motor torque appropriate for the detected situation to prevent acceleration of vehicle left and right sway and vehicle spin. Thus, the lateral stability of the vehicle can be secured.

According to the present disclosure, the occupant's unique injury risk information estimated in an actual collision situation is transmitted to the emergency system through the vehicle's emergency notification system, so that the occupant's exact injury situation can be provided to the medical institution. Additionally, following treatment of the occupant, medical data can be fed back to the crash optimization model so that the model and personalized injury risk information can be updated to better suit the occupant.

The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description below. will be.

1 is a block diagram showing the configuration modules of a vehicle equipped with a lateral control device according to an embodiment of the present disclosure.
Figure 2 is a flowchart of a lateral control method according to another embodiment of the present disclosure.
Figure 3 is a diagram showing a lateral control device according to an embodiment of the present disclosure from a logic module perspective.
Figure 4 is a flowchart of the process of determining the low friction situation of a vehicle according to the slip rate.
Figure 5 is a diagram showing a logic module that determines entry and release of the first entry condition.
Figure 6 is a flowchart of the process of determining the shaking of the vehicle based on the yaw rate of the vehicle.
Figure 7 is a diagram illustrating the factors and calculation process used to calculate the required yaw rate.
FIG. 8 is a diagram showing data related to a spin phenomenon of a vehicle due to continued regenerative braking of a conventional vehicle in a vehicle shaking situation.
FIG. 9 is a diagram showing data related to vehicle stability in a vehicle shaking situation due to stabilization torque output according to the present disclosure.

Hereinafter, with reference to the attached drawings, embodiments of the present disclosure will be described in detail so that those skilled in the art can easily practice them. However, the present disclosure may be implemented in many different forms and is not limited to the embodiments described herein.

In describing embodiments of the present disclosure, if it is determined that detailed descriptions of known configurations or functions may obscure the gist of the present disclosure, detailed descriptions thereof will be omitted. In addition, in the drawings, parts that are not related to the description of the present disclosure are omitted, and similar parts are given similar reference numerals.

In the present disclosure, when a component is said to be “connected,” “coupled,” or “connected” to another component, this is not only a direct connection relationship, but also an indirect connection relationship where another component exists in between. It may also be included. In addition, when a component is said to "include" or "have" another component, this does not mean excluding the other component, but may further include another component, unless specifically stated to the contrary. .

In the present disclosure, terms such as first, second, etc. are used only for the purpose of distinguishing one component from other components, and do not limit the order or importance of components unless specifically mentioned. Therefore, within the scope of the present disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, the second component in one embodiment may be referred to as a first component in another embodiment. It may also be called.

In the present disclosure, distinct components are intended to clearly explain each feature, and do not necessarily mean that the components are separated. That is, a plurality of components may be integrated to form one hardware or software unit, or one component may be distributed to form a plurality of hardware or software units. Accordingly, even if not specifically mentioned, such integrated or distributed embodiments are also included in the scope of the present disclosure.

In the present disclosure, components described in various embodiments do not necessarily mean essential components, and some may be optional components. Accordingly, embodiments consisting of a subset of the elements described in one embodiment are also included in the scope of the present disclosure. Additionally, embodiments that include other components in addition to the components described in the various embodiments are also included in the scope of the present disclosure.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments presented below and can be implemented in various different forms. The present embodiments are merely provided to ensure that the disclosure of the present invention is complete and to be understood by those skilled in the art It is provided to fully inform those who have the scope of the invention.

Hereinafter, with reference to FIG. 1, a lateral control device for costrigen steering of a vehicle according to an embodiment of the present disclosure will be described.

1 is a block diagram showing the configuration modules of a vehicle equipped with a lateral control device according to an embodiment of the present disclosure.

The vehicle 100 may be a moving object driven based on electrical energy. The vehicle 100 may be, for example, a mobile vehicle that uses a directly charged electric battery or a gas-based fuel cell as an energy source. In the case of a fuel cell, the vehicle 100 can use various types of gas that can generate electrical energy in the fuel cell, and the gas may be hydrogen, for example. However, it is not limited to this and various gases are applicable.

Vehicle 100 may refer to, for example, a device that can move. The mobile device may be a conventional passenger or commercial vehicle, a mobile office, or a mobile hotel. The vehicle may be a four-wheeled vehicle, such as a passenger car, SUV, or small truck, or may be a vehicle with more than four wheels, such as a large truck, container carrier, or heavy equipment vehicle. In the present disclosure, a four-wheeled vehicle is used as an example for convenience of explanation, but the embodiments according to the present disclosure are not limited to this but are applicable to all vehicles having a plurality of wheels other than four wheels. The vehicle 100 may be implemented as manned or autonomous driving (including semi-autonomous and fully autonomous driving).

Meanwhile, the vehicle 100 may communicate with other devices or other moving objects. At this time, as an example, the mobile object may communicate with another device based on cellular communication, WAVE communication, Dedicated Short Range Communication (DSRC), or other communication methods. In other words, communication networks such as LTE and 5G, WiFi communication networks, WAVE communication networks, etc. can be used as cellular communication networks. In addition, a short-range communication network used in mobile devices, such as DSRC, may be used, and is not limited to the above-described embodiment.

Specifically, the vehicle 100 includes a front wheel unit 102, a rear wheel unit 104, a sensor unit 112, a regenerative braking unit 114, a transceiver unit 116, a memory 118, a display 120, and a processor. It may include (122).

The front wheel part 102 and the rear wheel part 104 may be members that contact the ground and allow the vehicle to travel in a desired driving direction according to the user's manipulation. In the present disclosure, the front and rear are distinguished and named as front and rear wheel units 102 and 104 based on the front direction from which the driver of the vehicle gazes, but this is merely described for convenience. Therefore, the front and rear wheel parts 102 and 104 may be named oppositely depending on the viewpoint, and in cases where the driving direction is determined and controlled regardless of the driver's gaze direction, such as in an unmanned shuttle or autonomous driving, the front and rear wheel parts (102, 104) may simply be referred to as first and second wheel portions. Accordingly, the names according to the front and rear wheel parts 102 and 104 in this specification do not limit the scope of rights according to the present disclosure.

Depending on the design of the vehicle 100, any one of the front wheel portion 102 and the rear wheel portion 104 may be a drive wheel (or drive wheel), and the other wheel of the front wheel portion 102 and the rear wheel portion 104 may be a drive wheel (or drive wheel). It may be composed of an additional driven wheel (or driven wheel, non-driven wheel, etc.). The wheel portion related to the driven wheel may be mainly configured to have a power transmission system other than wheels and a motor.

The wheel part related to the driving wheel may include a wheel such as a tire, a motor that transmits driving force to the wheel, and a motor control module that controls motor torque, motor rotation direction, braking, etc. Additionally, the wheel portion related to the driving wheel may be driven by receiving power supplied from the battery 108 and passing through the inverter 110. In the case of a fuel cell, the battery 108 may include a hydrogen fuel cell with a plurality of stacks that generate electrical energy through a reaction between hydrogen supplied from the hydrogen tank 106 and oxygen introduced to the outside. The battery 108 can provide the generated energy to driving, lighting, air conditioning, and various electrical devices of the vehicle 100. The battery 112 may include, for example, a first battery that supplies energy to a drive wheel and high-power electrical equipment, and a second battery that supplies energy to low-power electrical equipment and charges the first battery. Here, the second battery may be comprised of a hydrogen fuel cell. Inverter 110 may convert one form of power, such as alternating current, from battery 108 to another form, such as direct current, and reduce the voltage.

Regardless of the driving wheel and the driven wheel, any one of the front wheel part 102 and the rear wheel part 104 may include a steering module that receives steering according to the steering operation. In addition, at least one of the front wheel unit 102 and the rear wheel unit 104 may be configured to have a wheel braking module that directly brakes the wheel by the user's operation of the brake module, for example, by pressing the brake pedal.

Additionally, taking four-wheel drive as an example in the present disclosure, the front wheel unit 102 may include a front left wheel unit 102a and a front right wheel unit 102b. The rear wheel portion 104 may include a rear left wheel portion 104a and a rear right wheel portion 104b. The left and right wheel parts may include the above-described modules and members depending on the driving wheel and article transmission function.

The sensor unit 112 may be equipped with various types of sensor modules to detect various states and situations occurring inside and outside the vehicle. The sensor unit 112 includes, for example, a speedometer that detects the speed of the vehicle 100, a steering sensor and wheel steering angle sensor that measure the steering angle of the steering and wheels, and a posture of the vehicle including the yaw of the vehicle 100. It may include a posture/orientation sensor that detects, a wheel sensor that measures the speed of each wheel of the front and rear wheel units 102 and 104, etc. The attitude/orientation sensor may be, for example, a gyro sensor, an IMU (Inertial Measurement Unit) sensor, etc. In addition, the sensor unit 112 may include a GPS sensor, an image sensor that provides visual images of the inside and outside of the vehicle, a distance sensor, etc., and may further include sensors that detect various situations not listed here.

The regenerative braking unit 114 brakes at least one of the front and rear wheel units 102 and 104 by adjusting the regenerative braking torque according to the user's regenerative braking command, rather than wheel braking by the brake module, and also brakes the battery ( The vehicle 100 can be controlled to charge 108). The regenerative braking unit 114 has a hardware interface or a software interface provided to enable touch input on the display 120, and can receive the user's command through the above-described interface. The hardware interface may be, for example, an operation key or button, and the software interface may be, for example, a soft key provided on the display 120. For example, through the interface, the user can turn on regenerative braking and request regenerative braking commands such as detailed control of braking level, braking change rate, deceleration, etc. in regenerative braking. The regenerative braking unit 114 may transmit the torque required for regenerative braking according to the regenerative braking control command to the processor 122.

The transceiver unit 116 can support mutual communication with moving objects around the vehicle, a traffic intelligence service server or roadside base station, servers providing various vehicle services, or edge devices.

The display 120 may function as a user interface. The display 120 displays the operating state of the vehicle 100, control state, route/traffic information, shaking state of the vehicle 100, regenerative braking control state, battery state, gas remaining amount information, and user information by the processor 122. Requested content, etc. can be displayed to be output. Taking the vehicle shaking state and regenerative braking control state as an example, the display 120 displays low-friction road information on the driving road, road surface conditions, vehicle shaking state according to steering, slip state, and vehicle stability information related to slip prediction, and regenerative braking. The processing status and results of the processor 122 according to the command may be provided to the user. More specifically, the processing status and results of the processor 122 include the execution status of the regenerative braking command requested by the user, the current braking level or braking change rate, vehicle control conditions for releasing vehicle slip, such as steering guidance, vehicle speed guidance, etc. You can. The display 120 is configured as a touch screen capable of detecting user input, and can receive a user's request instructing the processor 122.

The memory 118 stores applications and various data for controlling the vehicle 100, and can load applications or read and write data at the request of the processor 122. In the present disclosure, the memory 118 stores an application and at least one instruction for securing lateral stability during costrigen steering, and the processor 122 is configured to execute the application and instructions stored in the memory 118. You can.

The processor 122 performs overall control of the vehicle 100 and, in relation to the present disclosure, executes applications and instructions stored in the memory 118 to ensure lateral stability when steering the vehicle 100. The operation can be controlled.

Specifically, the processor 122 may receive a request related to regenerative braking control from the user through the interface. The processor 122 determines whether the yaw rate error between the required yaw rate and the actual yaw rate satisfies the first entry condition, and the slip ratio calculated based on the wheel speed satisfies the second entry condition. You can determine whether it is sufficient. When the yaw rate error and slip rate satisfy the first and second entry conditions, respectively, the processor 122 applies stabilization torque as the motor torque of the motor driving the wheel, and at least one of the error and slip rate is the first entry condition. And when the second entry condition is not satisfied, the front and rear wheel units 102 and 104 can be controlled to apply the required torque according to regenerative braking control using motor torque.

The lateral control device according to the present disclosure includes at least a front wheel unit 102, a rear wheel unit 104, a regenerative braking unit 114, a processor 122, and a memory 118, and the front and rear wheel units 102 and 104 ) may be a device configured to implement the above-described control by the processor 122. Control of the above-described processor 122 will be described in detail with reference to FIGS. 2 to 7.

With reference to FIGS. 2 to 7 , a lateral control method during costrigen steering of a vehicle will be described. Figure 2 is a flowchart of a lateral control method according to another embodiment of the present disclosure. Figure 3 is a diagram showing a lateral control device according to an embodiment of the present disclosure from a logic module perspective. The lateral control method of the present disclosure is described as an example of being implemented with the lateral control device illustrated in FIG. 1, and the processor 122 uses the logical software module or the logical software module illustrated in FIG. 3 to implement the lateral control method. Hardware modules can be provided. Additionally, for convenience of explanation, in the present disclosure, it is exemplified that the front and rear wheel units 102 and 104 are four-wheeled vehicles each having two wheels.

First, the regenerative braking unit 114 may receive a regenerative braking command requested by the user through an interface and transmit it to the processor 122. The regenerative braking command may, for example, turn on the regenerative braking and may also include precise control such as braking level, braking change rate, deceleration, etc. in the regenerative braking. When regenerative braking is turned on, the vehicle 100 can control deceleration of the front and rear wheel units 102 and 104 at a preset braking change rate. In addition, if the user requests precise control such as braking level, braking change rate, etc., other than the set value, the regenerative braking unit 114 may transmit a command related to the precise control to the processor 122. The processor 122 can check the user's required torque according to regenerative braking control through the vehicle speed detected by the speedometer along with the set value or precise control command. In FIG. 3 , this may correspond to the Costrigen required torque according to the regenerative braking lever and vehicle speed.

Next, the processor 122 may check whether the slip rate and yaw rate error satisfy the first and second entry conditions corresponding to each parameter (S105).

In Figure 3, this may correspond to 'entry Slip Ratio satisfaction' and 'entry Yaw Rate error judgment'.

The point of confirming whether the slip rate satisfies the first entry condition will be described with reference to FIGS. 4 and 5. Figure 4 is a flowchart of the process of determining the low friction situation of a vehicle according to the slip rate. Figure 5 is a diagram showing a logic module that determines entry and release of the first entry condition. Meanwhile, this may correspond to each wheel speed input, which is a factor used in 'entry Slip Ratio satisfaction' and slip rate calculation in FIG. 3.

Referring to FIG. 4, the processor 122 may receive the speed of each wheel measured by the wheel sensor (S205). Each wheel speed may be the wheel speed of each of the front left and right wheel parts 102a and 102b, and the wheel speed of each of the rear left and right wheel parts 104a and 104b. In addition, the processor 122 can recognize in advance the wheel part that functions as a driving wheel and the wheel part that functions as a driven wheel.

Next, when the processor 122 confirms that the speed of the driven wheel is faster than the driving wheel, it can calculate the left and right slip rates and calculate the slip rate based on these slip rates (S210).

The fact that the speed of the driven wheel is faster than that of the driving wheel may mean that the driving road is in a low-friction situation, causing the driving wheel to temporarily rotate abnormally or stop, that is, the driving wheel is locked.

The left and right slip rates can be calculated according to the driving state based on Equation 1. The driving state may be either front-wheel drive in which the front wheel unit 102 is a driving wheel or rear-wheel drive in which the rear wheel unit 104 is a driving wheel. Looking at Equation 1, it can be seen that the slip rate is calculated as the ratio of the difference between the driven wheel and the driving wheel with respect to the driven wheel.

[Equation 1]

In the case of rear-wheel drive, Equation 1 is applied as Equation 2, and the left and right slip rates can be calculated using Equation 2. In this case, the non-driving wheel speed may be the speed of the front left and right wheel parts 102a and 102b, and the driving wheel speed may be the speed of the rear left and right wheel parts 104a and 104b. Looking at Equation 2, it can be seen that the left slip rate is calculated based on the speeds of the driven left wheel and the driven left wheel, and the right slip rate is calculated based on the speeds of the driven right wheel and the driven right wheel.

Here, σ _LH , σ _RH , V _FL , V _RL , V _FR , and V _RR are the left slip rate, right slip rate, front left wheel speed, rear left wheel speed, front right wheel speed, and rear right wheel speed, respectively. You can.

[Equation 2]

In the case of front-wheel drive, Equation 1 is applied as Equation 3, and the left and right slip rates can be calculated using Equation 3. In this case, the non-driving wheel speed may be the speed of the rear left and right wheel parts 104a and 104b, and the driving wheel speed may be the speed of the front left and right wheel parts 102a and 102b. Equation 3 is also similar to Equation 2, and it can be seen that the left slip rate is calculated based on the speeds of the driven left wheel and the driven left wheel, and the right slip rate is calculated based on the speeds of the driven right wheel and the driven right wheel. You can. Here, σ _LH , σ _RH , V _FL , V _RL , V _FR and V _RR are the same as the factors in Equation 2.

[Equation 3]

Subsequently, the processor 122 may calculate the slip rate based on the left slip rate and right slip rate calculated using Equation 2 or 3. For example, the slip rate can be finally calculated based on the maximum value of the left and right slip rates, as shown in Equation 4. _{Here , σ}

[Equation 4]

Next, the processor 122 determines whether the calculated slip rate is greater than or equal to the critical slip rate (S215), and if the determination result is greater than or equal to the critical slip rate, the processor 122 may determine that the sleep rate satisfies the first entry condition (S220). As a result of the determination, if the sleep rate is confirmed to be less than the critical sleep rate, the processor 122 may confirm that the sleep rate does not satisfy the first entry condition.

The critical slip rate related to the first entry condition may be a value at which it is determined that the vehicle 100 has entered a low friction situation on the driving road. The critical slip rate may be set to, for example, 2%, and the reason why the critical slip rate is set to 2% is that the regenerative braking controlled vehicle 100 depends on the road surface condition and the user's operation, such as the degree of steering, vehicle speed, etc. This is because it is a value related to the possibility of slipping or rocking, that is, the possibility of certain loss of lateral stability. As illustrated in FIG. 5, it may be determined that the first entry condition is satisfied if the slip rate and the critical slip rate _σ

The value of the above-mentioned critical slip rate was obtained experimentally, but may vary depending on detailed design details of the vehicle 100 and road conditions.

Next, the processor 122 may check whether the sleep rate that has entered the threshold sleep rate or higher changes and reaches the release condition (S225). If the varying slip rate reaches the release condition, the processor 122 estimates that the vehicle 100 is out of the low friction situation, and if the release condition is not reached, the processor 122 determines that the slip rate is still in the first entry condition. It can be judged that the conditions are satisfied.

The release slip rate of the release condition may be set to be smaller than the critical slip rate. The release condition is not simply satisfied when the release slip rate is reached, but can be satisfied when a slip rate below the release slip rate continues above the release threshold by further applying a hysteresis condition.

As in the example of FIG. 5, if the slip rate changes and the release slip rate, for example, continues below 0 for more than 0.2 seconds, which is the release threshold time, the first entry condition for the slip rate may be released. The release slip rate and release critical time may be values at which it is determined that the vehicle 100 has substantially escaped a low friction situation on a driving road. The release slip rate and release critical time may be obtained experimentally, but may vary depending on detailed design details of the vehicle 100 and road conditions.

The point of checking whether the yaw rate error satisfies the second entry condition will be described with reference to FIG. 6. Figure 6 is a flowchart of the process of determining the shaking of the vehicle based on the yaw rate of the vehicle.

Referring to FIG. 6, the processor 122 may calculate the required yaw rate and receive the actual yaw rate of the vehicle 100 obtained from the attitude/orientation sensor (S305).

Details regarding this may correspond to 'desired yaw rate calculation' and 'Yaw rate' in FIG. 3.

The required yaw rate can theoretically be calculated by Equation 5 based on the cornering coefficient.

[Equation 5]

The relational expression for the required yaw rate including the cornering coefficient is theoretically similar to the actual vehicle behavior, but the value of the cornering coefficient is not easy to measure. Even if the cornering coefficient value is obtained, it may change differently depending on the degree of tire wear and differences in air pressure. Additionally, even if a vehicle manufacturer develops and manufactures a vehicle with the cornering coefficient value of a specific tire, there is a possibility that the tires may be replaced with tires from various manufacturers in the actual field. To eliminate these variables, the present disclosure uses driver steering demand through Ackerman geometry to determine the required yaw rate.

Figure 7 is a diagram illustrating the factors and calculation process used to calculate the required yaw rate.

Referring to FIG. 7, assuming that the turning radius (R=r _RR ) is sufficiently larger than the wheel base distance (l) between the front and rear wheels, that is, when the steering angle (α=δ) is small, the required yaw rate ( ) can be calculated by Equation 6. Here, V _veh is l, θ, and k may be the vehicle speed, wheel base distance, steering angle, and streering unit ratio, respectively. θ/k may correspond to the wheel steering angle (δ). In Figure 7, V _FL , V _RL , V _FR , and V _RR are substantially the same as the parameters in Equation 2.

[Equation 6]

Looking at Equation 6, the required yaw rate ( ) can be seen to be calculated based on the vehicle speed (V _veh ), wheel steering angle (δ), and wheel base distance (l).

Referring again to FIG. 6, the processor 122 may check whether the yaw rate error according to the difference between the required yaw rate and the actual yaw rate is greater than or equal to the reference error (S310).

The reference error related to the second entry condition may be a value at which the vehicle 100 is expected to turn excessively due to the user's operation, such as steering steering and vehicle speed. The reference error is related to the yaw rate error that the driver attempts to steer in the opposite direction when the vehicle 100 begins to deviate laterally, and can be set according to the design details of the vehicle 100 and road surface conditions.

As a result of the determination, if the yaw rate error is greater than the standard error, the processor 122 may determine whether the yaw rate error greater than the standard error continues for more than the error threshold time (S315).

In addition to the reference error, the error threshold time may be a detailed requirement related to the second entry condition. The error threshold considers the possibility that an error exists in at least one of the required yaw rate and the actual yaw rate, and it can be assumed that if the errors are continuously spaced apart for a certain period of time, there can be no error in both yaw rates. The error threshold time may be set to 200 ms, for example, but may vary depending on the design details of the vehicle 100 and road surface conditions.

As a result of the determination, if the yaw rate error greater than the standard error continues for more than the error threshold time, the processor 122 may finally determine that the yaw rate error satisfies the second entry condition (S320).

In contrast, if the determination results in steps S310 and S315 are less than the reference error or remain less than the error threshold time, the processor 122 may determine that the yaw rate error has not reached the second entry condition.

Returning again to S105 of FIG. 2, the processor 122 may check whether the slip rate and yaw rate errors calculated in FIGS. 2 and 4 satisfy the corresponding first and second entry conditions. The stabilization torque can be output so that the stabilization torque is applied by the motor torque of the motor driving the front and rear wheel parts 102 and 104 (S115).

The stabilization torque is a preset torque and, as illustrated in FIG. 3, may be zero torque. Without being limited thereto, if lateral stability of the vehicle 100 can be maintained in a low friction situation, the stabilizing torque may not be limited to the illustrated value.

If at least one of the slip rate and yaw rate error does not satisfy the first and second entry conditions, the processor 122 uses motor torque to satisfy the driver's request according to the regenerative braking control requested through the regenerative braking unit 114. By outputting torque, the motors of the front and rear wheel units 102 and 104 can be controlled (S120). In FIG. 3, this may correspond to the cross-regen required torque according to regenerative braking control being output as motor torque.

FIG. 8 is a diagram showing data related to a spin phenomenon of a vehicle due to continued regenerative braking of a conventional vehicle in a vehicle shaking situation.

In a conventional vehicle, even if lateral stability is lost due to a low friction situation after regenerative braking control is started, regenerative braking control is maintained, as shown in the motor torque graph. As a result, the vehicle turns opposite to the required steering angle, or an undesired turning motion is caused even when the steering angle is 0. Furthermore, it can be confirmed through the Yaw Rate and Slip Ratio graphs that even when turning motion is induced, the required torque according to regenerative braking control is maintained as motor torque, and the vehicle's lateral stability is rapidly lost.

FIG. 9 is a diagram showing data related to vehicle stability in a vehicle shaking situation due to stabilization torque output according to the present disclosure.

As shown in the motor torque graph according to the present disclosure, a situation in which loss of lateral stability is estimated as the vehicle enters a low friction situation is detected, and zero torque as stabilization torque is applied instead of the driver's required torque according to regenerative braking control. Printed out.

As shown in the steering angle, yaw rate, and control flag graphs, it was confirmed that by detecting the entry of the above situation and controlling the wheel motor with stabilizing torque, vehicle shaking and spin were significantly reduced. That is, according to the embodiment of the present disclosure, lateral stability of the vehicle can be secured when decelerating by regenerative braking control on a low friction road.

Exemplary methods of the present disclosure are expressed as a series of operations for clarity of explanation, but this is not intended to limit the order in which the steps are performed, and each step may be performed simultaneously or in a different order, if necessary. In order to implement the method according to the present disclosure, other steps may be included in addition to the exemplified steps, some steps may be excluded and the remaining steps may be included, or some steps may be excluded and additional other steps may be included.

The various embodiments of the present disclosure do not list all possible combinations but are intended to explain representative aspects of the present disclosure, and matters described in the various embodiments may be applied independently or in combination of two or more.

Additionally, various embodiments of the present disclosure may be implemented by hardware, firmware, software, or a combination thereof. For hardware implementation, one or more ASICs (Application Specific Integrated Circuits), DSPs (Digital Signal Processors), DSPDs (Digital Signal Processing Devices), PLDs (Programmable Logic Devices), FPGAs (Field Programmable Gate Arrays), general purpose It can be implemented by a processor (general processor), controller, microcontroller, microprocessor, etc.

The scope of the present disclosure is software or machine-executable instructions (e.g., operating system, application, firmware, program, etc.) that cause operations according to the methods of various embodiments to be executed on a device or computer, and such software or It includes non-transitory computer-readable medium in which instructions, etc. are stored and can be executed on a device or computer.

Claims (18)

In the lateral control method when steering a vehicle,
Receiving a request related to regenerative braking control;
determining whether a slip ratio calculated based on the wheel speed satisfies a first entry condition;
determining whether the yaw rate error between the required yaw rate and the actual yaw rate satisfies a second entry condition;
In response to the slip rate and the error satisfying first and second entry conditions, respectively, applying stabilization torque as a motor torque of a motor driving the wheel; and
In response to at least one of the slip rate and the error not satisfying first and second entry conditions, applying a required torque according to the regenerative braking control to the motor torque.
According to claim 1,
The stabilizing torque is a preset torque and is zero torque.
According to claim 1,
The first entry condition is a condition in which the slip rate is greater than or equal to a critical slip rate.
According to claim 1,
If the slip rate that entered above the threshold slip rate changes and the condition continues for more than the release threshold time below the release slip rate that is less than the threshold slip rate, the first entry condition is released, further comprising: Lateral control method.
According to claim 1,
In addition to the wheel having front and rear wheels, one of the front and rear wheels is a driving wheel, and the other wheel of the front and rear wheels is a driven wheel,
When the speed of the driven wheel is faster than the driving wheel, the slip rate is calculated as a ratio of the difference between the driven wheel speed and the driving wheel speed to the driven wheel speed.
According to claim 5,
The driven wheel has a driven left wheel and a driven right wheel, and the driving wheel has a driven left wheel and a driven right wheel,
The slip rate is the maximum value of the left slip rate calculated based on the speeds of the driven left wheel and the driven left wheel and the right slip rate calculated based on the speeds of the driven right wheel and the driven right wheel. Calculated based on the lateral control method.
According to claim 1,
The required yaw rate is calculated based on the vehicle's speed, wheel steering angle, and wheel base distance between front and rear wheels.
According to claim 1,
The second entry condition is a condition in which the yaw rate error continues above the reference error.
According to claim 8,
The second entry condition is a condition in which the yaw rate error greater than the reference error continues for more than the error threshold time.
In the lateral control device for costrigen steering of a vehicle,
a memory storing at least one instruction; and
A processor that executes the at least one instruction stored in the memory,
The processor,
Receive requests related to regenerative braking control,
Determine whether the slip rate calculated based on the wheel speed satisfies the first entry condition,
Determine whether the yaw rate error between the required yaw rate and the actual yaw rate satisfies the second entry condition,
In response to the slip rate and the error satisfying first and second entry conditions, respectively, applying stabilization torque as a motor torque of a motor driving the wheel,
Transverse control device, configured to apply a required torque according to the regenerative braking control to the motor torque in response to at least one of the slip rate and the error not satisfying the first and second entry conditions.
According to claim 10,
The stabilizing torque is a preset torque and is zero torque.
According to claim 10,
The first entry condition is a condition in which the slip rate is greater than or equal to a critical slip rate.
According to claim 10,
The processor is configured to release the first entry condition when a condition in which the sleep rate entered above the threshold slip rate changes and continues for more than the release threshold time below the release slip rate less than the threshold slip rate. , transverse control device.
According to claim 10,
In addition to the wheel having front and rear wheels, one of the front and rear wheels is a driving wheel, and the other wheel of the front and rear wheels is a driven wheel,
When the speed of the driven wheel is faster than the driving wheel, the slip rate is calculated as a ratio of the difference between the driven wheel speed and the driving wheel speed to the driven wheel speed.
According to claim 14,
The driven wheel has a driven left wheel and a driven right wheel, and the driving wheel has a driven left wheel and a driven right wheel,
The slip rate is the maximum value of the left slip rate calculated based on the speeds of the driven left wheel and the driven left wheel and the right slip rate calculated based on the speeds of the driven right wheel and the driven right wheel. Calculated based on the lateral control device.
According to claim 10,
The required yaw rate is calculated based on the vehicle's speed, wheel steering angle, and wheel base distance between front and rear wheels.
According to claim 10,
The second entry condition is a condition in which the yaw rate error continues above the reference error.
According to claim 17,
The second entry condition is a condition in which the yaw rate error greater than the reference error continues for more than the error threshold time.

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