KR20230106400A - Steering system and control method therefor - Google Patents

Abstract

The present invention relates to a steering system using a joystick and a control method thereof. a micromanipulation unit that is manipulated for fine steering of the wheel; A basic steering angle is calculated based on the operation state of the basic control unit, a fine steering angle is calculated based on the operation state of the micro control unit, a final steering angle is calculated by adding the basic steering angle and the fine steering angle, and the final steering angle is used to steer the wheel. A steering system comprising a steering angle control unit for controlling and a control method thereof is introduced.

Description

Steering system and control method thereof {Steering system and control method therefor}

The present invention provides a steering system that improves vehicle steering stability and reduces driver's fatigue by performing fine steering control as necessary in addition to basic steering control of a joystick and performs fail-safe steering using fine steering control technology, and the same It's about the control method.

The Steer-by-Wire (SbW) system is a steering system that eliminates the mechanical connection structure between the steering wheel and the steering rack and replaces it with electronic control.

The structure of the steering rack at the bottom of the SBW system is similar to that of the existing MDPS (Motor Driven Power Steering) system, but a feedback actuator is added to the steering wheel at the top to generate and transmit steering reaction force to the driver.

Recently, research on a joystick as a steering interface for future mobility is being actively conducted.

Joysticks are largely divided into hand-operated joysticks and finger-operated joysticks according to the operation method, and depending on the operating principle, regardless of the tilt or pressure of the joystick, It can be divided into a displacement joystick in which a constant input is applied in a direction, and an isometric joystick in which an input is applied according to the tilt and pressure of the joystick.

However, in order to steer using the joystick, the relationship between the displacement of the joystick and the actual front wheel position must be kept constant, and the driving situation of the vehicle must be fed back through the joystick. Research on a kind of hybrid type joystick that provides active force feedback to a displacement joystick is being actively conducted.

However, although the joystick is suitable for controlling the attitude of the vehicle, it has a disadvantage in that it has a small movable range compared to conventional steering wheels, making it difficult to precisely control the vehicle, and in particular, it is very difficult to fine-tune steering.

Accordingly, oversteer frequently occurs compared to conventional steering wheels, resulting in poor steering stability of the vehicle and increased driver fatigue due to repeated corrective steering.

The matters described as the background art above are only for improving understanding of the background of the present invention, and should not be taken as an admission that they correspond to prior art already known to those skilled in the art.

KR 10-2019-0074555 A

The present invention has been made to solve the above-described problems, and a steering system and control method for improving vehicle steering stability and reducing driver's fatigue by performing fine steering control as necessary in addition to basic steering control of a joystick. is to provide

Another object of the present invention is to provide a steering system and a control method for performing fail-safe steering using a fine steering control technology when basic steering control of a joystick is impossible.

The configuration of the steering system of the present invention for achieving the above object is a basic operation unit that is operated by steering for basic steering of a wheel; a micromanipulation unit that is manipulated for fine steering of the wheel; A basic steering angle is calculated based on the operation state of the basic control unit, a fine steering angle is calculated based on the operation state of the micro control unit, a final steering angle is calculated by adding the basic steering angle and the fine steering angle, and the final steering angle is used to steer the wheel. It may be characterized by comprising a; steering angle control unit for controlling.

The basic manipulation unit may have a joystick shape capable of direction manipulation, and the fine manipulation unit may be provided in the form of a button on the basic manipulation unit.

An angle sensor for sensing a steering angle according to manipulation of the basic manipulation unit may be further included, and the basic steering angle may be calculated based on a relationship between the steering angle and vehicle speed.

A force sensor for detecting a force sensing value with respect to a manipulation direction of the basic manipulation unit may be further included, and a micro steering angle may be calculated based on a relationship between an on-time of the micro manipulation unit, a force sensing value, and vehicle speed.

When an absolute value of the force sensing value exceeds a threshold value in an ON operation state of the micro manipulation unit, a micro steering angle calculation may be activated.

The micro-steering angle may be determined in proportion to an ON operation holding time of the micro-control unit.

When the micro-control unit is turned on, the micro-steering angle may gradually increase according to a set increase rate for a time during which the micro-control unit is operated.

When the micro-manipulation unit is turned off, the micro-steering angle may gradually decrease according to a set decrease rate.

When it is determined that the basic steering angle cannot be calculated in a fail state, the final steering angle can be calculated based on the relationship between the fine steering angle and the vehicle speed.

The configuration of the control method of the steering system according to the present invention comprises: calculating, by a steering angle controller, a basic steering angle based on an operating state of a basic steering unit operated for basic steering of a wheel; calculating, by a steering angle control unit, a fine steering angle based on a manipulation state of a fine manipulation unit in which a wheel is manipulated for fine steering; A steering angle control unit calculating a final steering angle by adding the basic steering angle and the fine steering angle, and controlling the wheel to be steered with the final steering angle; may be characterized in that it comprises a.

Through the above problem solving means, the present invention implements a fine steering command as needed in addition to basic left and right steering angle commands by adding a button for fine steering to the steering joystick, thereby performing fine steering of the vehicle.

Therefore, precise steering control is possible even through steering control using a joystick, thereby improving the steering stability of the vehicle, and also, since fine steering correction is possible, frequent steering correction is unnecessary, thereby reducing driver's fatigue. .

In addition, when it is impossible to calculate the basic steering angle of the joystick, there is an advantage of performing fail-safe steering by replacing the fine steering angle with the basic steering angle and performing emergency steering in case of emergency.

1 is a view illustrating a steering mechanism of a joystick type according to the present invention.
2 is a configuration diagram of a steering system according to the present invention.
3 is a block diagram showing a process of determining a final steering angle by a control unit of a steering system according to the present invention.
4 is a block diagram for explaining a method for determining a basic steering angle according to the present invention.
5 is a block diagram for explaining a method for determining a fine steering angle according to the present invention.
6 is a view for explaining an operation in which the amount of fine steering is determined according to the on-manipulation time of the fine manipulation unit and the force sensing value detected by the force sensor in the present invention.
7 is a block diagram for explaining a method for determining a final steering angle according to the present invention.
8 is a flowchart illustrating a process of controlling a steering system according to the present invention.

Specific structural or functional descriptions of the embodiments of the present invention disclosed in this specification or application are merely illustrated for the purpose of explaining the embodiments according to the present invention, and the embodiments according to the present invention may be implemented in various forms. It may be and should not be construed as being limited to the embodiments described in this specification or application.

Embodiments according to the present invention can apply various changes and can have various forms, so specific embodiments are illustrated in the drawings and described in detail in this specification or application. However, this is not intended to limit the embodiments according to the concept of the present invention to specific disclosures, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The above terms are only for the purpose of distinguishing one component from another component, e.g., without departing from the scope of rights according to the concept of the present invention, a first component may be termed a second component, and similarly The second component may also be referred to as the first component.

It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle. Other expressions describing the relationship between elements, such as "between" and "directly between" or "adjacent to" and "directly adjacent to", etc., should be interpreted similarly.

Terms used in this specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "comprise" or "having" are intended to designate that the described feature, number, step, operation, component, part, or combination thereof exists, but one or more other features or numbers However, it should be understood that it does not preclude the presence or addition of steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined herein, they are not interpreted in an ideal or excessively formal meaning. .

A preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating a steering mechanism of a joystick type according to the present invention, and FIG. 2 is a configuration diagram of a steering system according to the present invention.

As shown in the drawing, the present invention is a steering system in which steering operation of a vehicle is performed through a joystick rather than a conventional steering wheel.

Accordingly, in the description of the steering system, signals related to steering operation are detected by a sensor provided in the joystick according to the operation of the joystick, and the detected signals are input to the sensor signal processing unit in the control unit and converted into digital signals.

In addition, various signals reflecting the driving state of the vehicle may be detected together and received by the CAN signal transmission/reception unit of the control unit, and the received signals may be transmitted to other devices in the vehicle through CAN communication of the vehicle.

In addition, the current state information of the joystick is displayed on the display device through the joystick information display unit, thereby providing the driver with the state information of the joystick.

In addition, as a joystick control logic in the control unit, a steering angle control unit 200 that determines the vehicle wheel steering angle and a reaction force control unit that determines the amount of reaction force applied to the driver when the joystick is operated are included.

The steering angle control unit 200 is a technical feature of this application and will be described in detail below.

In addition, the reaction force motor controller controls the joystick reaction force motor 300 to implement the amount of reaction force determined by the reaction force controller.

And, the vehicle wheel control unit controls the steering actuator to follow the steering angle determined by the steering angle control unit 200 .

Meanwhile, FIG. 3 is a block diagram showing a process of determining a final steering angle by a control unit of a steering system according to the present invention.

Referring to Figures 1 and 3, the steering system of the present invention, the basic operation unit 100 is operated for the basic steering of the wheel; a fine manipulation unit 110 that is manipulated for fine steering of the wheel; The basic steering angle is calculated based on the operating state of the basic manipulation unit 100, the fine steering angle is calculated based on the operating state of the fine manipulation unit 110, the final steering angle is calculated by adding the basic steering angle and the fine steering angle, and the final steering angle is calculated. It is configured to include; a steering angle control unit 200 that controls to steer the wheel at a steering angle.

For example, the basic manipulation unit 100 has the shape of a bar-shaped joystick capable of direction manipulation, and the basic steering angle calculation unit 210 calculates the basic steering angle corresponding to the steering manipulation according to the left and right steering manipulation of the basic manipulation unit 100. do.

Further, the micromanipulation unit 110 is provided in the form of a button in the basic operation unit 100, and a button is provided at the top of the joystick to enable on/off operation depending on whether or not the button is pressed.

According to the on/off manipulation of the micro-manipulation unit 110, the micro-steering angle calculator 220 calculates a micro-steering angle corresponding to the manipulation of the micro-manipulation unit 110.

The steering angle control unit 200 includes the basic steering angle calculation unit 210, the fine steering angle calculation unit 220, and the final steering angle calculation unit 230, and the final steering angle calculation unit 230 calculates the basic steering angle. The final steering angle is determined by adding the basic steering angle calculated in the unit 210 and the fine steering angle calculated in the fine steering angle calculation unit 220, and the determined final steering angle command is applied to the steering actuator 400 to control the steering angle of the wheel. do.

As such, the present invention implements a fine steering command as needed in addition to basic left and right steering angle commands by adding a button for fine steering to the steering joystick, thereby performing fine steering of the vehicle.

Therefore, precise steering control is possible even through steering control using a joystick, thereby improving the steering stability of the vehicle, and also enabling finely corrected steering, which eliminates the need for frequent corrected steering, thereby reducing driver's fatigue.

Meanwhile, FIG. 4 is a block diagram for explaining a method for determining a basic steering angle according to the present invention.

Referring to the drawings, the present invention further includes an angle sensor 120 for sensing a steering angle by the basic manipulation unit 100.

Also, the basic steering angle may be calculated based on the relationship between the steering angle and vehicle speed.

Here, the angle sensor 120 is provided on the joystick to sense a steering angle according to left and right steering of the joystick.

That is, when the steering angle and vehicle speed according to the operation of the joystick are input to the basic steering angle calculating unit 210, the vehicle speed scale for the vehicle speed is determined, and the steering ratio is determined according to the vehicle speed scale for the corresponding steering angle, so that the basic steering angle can be calculated. .

For example, since there are many situations where the steering angle of a wheel is large, such as a parking/U-turn situation in a low-speed region, the steering ratio is set relatively large.

On the other hand, in the high-speed range, the vehicle rotates in the yaw direction even at a small steering angle, and tire slip occurs at a large steering angle, causing the vehicle to become unstable. Therefore, the steering ratio is set relatively small to enable stable steering.

5 is a block diagram for explaining a method for determining a fine steering angle according to the present invention.

Referring to the drawings, the present invention is configured to further include a force sensor 130 for detecting a force sensing value with respect to the manipulation direction of the basic manipulation unit 100.

Further, the fine steering angle may be calculated based on the relationship between the on-time of the fine manipulation unit 110, the force sensing value, and the vehicle speed.

For example, the force sensor 130 detects a negative (-) force sensing value when the driver applies force by steering the joystick in the left direction, and detects a positive (+) force sensing value when applying force in the right direction. It is possible to check the left and right steering direction by detecting The force sensing value may be a torque value for left and right rotation of the basic manipulation unit 100 .

That is, when the force sensing value is detected as the driver steers the joystick to the left or right in a state in which the ON manipulation signal of the micro-manipulation unit 110 is input to the micro-steering angle calculation unit 220, the micro-control unit 110 is operated. Depending on the time, the fine steering amount for the corresponding steering direction is calculated.

In addition, since the vehicle speed scale for the vehicle speed is determined, the steering ratio is determined according to the input vehicle speed, so that the fine steering angle can be calculated.

In addition, FIG. 6 is a diagram for explaining an operation in which the amount of fine steering is determined according to the ON operation time of the fine manipulation unit 110 and the force sensing value detected by the force sensor 130 in the present invention.

Referring to the drawing, in the present invention, when the absolute value of the force sensing value exceeds the threshold value in the on-manipulation state of the micro-manipulation unit 110, the micro-steering angle calculation may be activated.

For example, assuming that the threshold value is α, the fine steering angle calculation is activated when the force sensing value exceeds -α according to leftward steering of the joystick.

In addition, when the force sensing value exceeds α even when the joystick is steered in the right direction, fine steering angle calculation is activated.

That is, by setting a threshold value to the force sensing value and controlling the fine steering operation not to be performed within the threshold value, sudden steering change in the left and right directions is prevented.

In addition, as shown in FIG. 6 , the micro steering angle may be determined in proportion to an ON operation holding time of the micro manipulation unit 110 .

Preferably, when the micro-manipulation unit 110 is turned on, the micro-steering angle is gradually increased according to a set increase rate for a time during which the micro-manipulation unit 110 is operated.

That is, as the operating time continues in the state in which the micro-manipulation unit 110 is turned on, the amount of micro-control increases linearly up to a preset maximum value based on a preset increase rate.

On the other hand, when the micro-manipulation unit 110 is turned off, the micro-steering angle is configured to gradually decrease according to the set decrease rate.

That is, when the fine manipulation unit 110 is operated from an on state to an off state, the amount of fine steering decreases linearly based on a preset reduction rate.

For reference, the slope of the increase rate at which the amount of fine steering increases may be set more gently than the slope at the rate of decrease at which the amount of fine steering decreases.

Meanwhile, FIG. 7 is a block diagram for explaining a method for determining a final steering angle according to the present invention.

Referring to the drawings, the present invention may calculate the final steering angle based on the relationship between the fine steering angle and the vehicle speed when it is determined that the calculation of the basic steering angle is impossible.

For example, in a situation where the steering system operates normally, the final steering angle command is applied to the steering actuator 400 by calculating the basic steering angle and the fine steering angle and calculating the final steering angle by adding the calculated basic steering angle and the fine steering angle.

However, when a failure of the joystick angle sensor 120 occurs, it is impossible to calculate the basic steering angle. In particular, when the joystick steering mechanism is applied to the SBW system, since the hardware coupling between the wheel and the joystick is removed, the driver's steering intention cannot be transmitted to the wheel.

Therefore, in this case, by replacing the fine steering angle with the basic steering angle, emergency steering can be performed in case of emergency to perform failsafe steering. Of course, since the steering angle is small, the fine steering angle can be amplified through the vehicle speed scale and replaced with an emergency steering command in case of failure.

Meanwhile, the control method of the steering system according to the present invention includes the steps of calculating, by the steering angle control unit 200, a basic steering angle based on the operation state of the basic operation unit 100 that is operated for basic steering of a wheel; calculating, by the steering angle controller 200, a fine steering angle based on an operating state of the fine manipulation unit 110 in which the wheel is manipulated for fine steering; The steering angle control unit 200 calculates a final steering angle by summing the basic steering angle and the fine steering angle, and controls the wheel to be steered with the final steering angle.

For reference, the steering angle control unit 200 according to an exemplary embodiment of the present invention is a non-volatile memory configured to store data related to an algorithm configured to control the operation of various components of a vehicle or software instructions for reproducing the algorithm (shown in FIG. not shown) and a processor (not shown) configured to perform an operation described below using data stored in a corresponding memory. Here, the memory and the processor may be implemented as individual chips. Alternatively, the memory and processor may be implemented as a single chip integrated with each other. A processor may take the form of one or more processors.

8 is a flowchart illustrating a process of controlling a steering system according to the present invention.

Accordingly, a process of controlling the steering system of the present invention will be described below with reference to FIG. 8 .

When a steering operation is performed by the joystick, signals detected by sensors provided in the joystick are input, and a vehicle speed signal and the like are input together with the signals (S10).

Accordingly, the basic steering angle calculation unit 210 calculates the basic steering angle based on the relationship between the steering angle of the joystick and the vehicle speed (S20).

Then, the fine steering angle calculation unit 220 calculates the fine steering amount based on the button manipulation signal and the force sensing value, and calculates the fine steering angle by multiplying the calculated fine steering amount by the vehicle speed scale according to the vehicle speed (S30).

Specifically, when the manipulation signal of the button is turned on and the absolute value of the force sensing value is greater than a preset threshold value (ex: α), the fine steering angle calculation is activated, and as the activation continues, the fine steering angle adjusts to the preset increase rate. will increase according to

Next, it is determined whether the angle sensor 120 is out of order (S40).

As a result of the determination in step S40, when the angle sensor 120 operates normally and the basic steering angle is normally calculated, the final steering angle is calculated by adding the basic steering angle and the fine steering angle, and the calculated final steering angle command is provided to the steering actuator 400 Do (S50).

Accordingly, the steering angle of the wheel is controlled according to the final steering angle (S70).

On the other hand, as a result of the determination in step S40, if the angle sensor 120 fails and the basic steering angle cannot be calculated, the vehicle is steered using only the fine steering angle instead of the basic steering angle (S60).

That is, the final steering angle is calculated by amplifying the fine steering angle through the vehicle speed scale according to the vehicle speed, and emergency steering is performed with the calculated final steering angle.

Accordingly, the steering angle of the wheel is controlled according to the final steering angle (S70).

As described above, the present invention implements a fine steering command as needed in addition to basic right and left steering angle commands by adding a button for fine steering to the steering joystick, thereby performing fine steering of the vehicle.

Therefore, precise steering control is possible even through steering control using a joystick, thereby improving the steering stability of the vehicle, and also enabling finely corrected steering, which eliminates the need for frequent corrected steering, thereby reducing driver's fatigue.

In addition, when it is impossible to calculate the basic steering angle of the joystick, failsafe steering can be performed by replacing the fine steering angle with the basic steering angle and performing emergency steering in case of emergency.

On the other hand, although the present invention has been described in detail only for the specific examples described above, it is obvious to those skilled in the art that various changes and modifications are possible within the scope of the technical idea of the present invention, and it is natural that these changes and modifications fall within the scope of the appended claims. .

100: basic operation unit
110: fine manipulation unit
120: angle sensor
130: force sensor
200: steering angle control unit
210: basic steering angle calculation unit
220: fine steering angle calculation unit
230: final steering angle calculation unit
300: reaction motor
400: steering actuator

Claims (10)

Basic steering control unit for basic steering of the wheel;
a micromanipulation unit that is manipulated for fine steering of the wheel;
A basic steering angle is calculated based on the operation state of the basic control unit, a fine steering angle is calculated based on the operation state of the micro control unit, a final steering angle is calculated by adding the basic steering angle and the fine steering angle, and the final steering angle is used to steer the wheel. Steering system comprising a; steering angle control unit for controlling. The method of claim 1,
The basic operation unit has a joystick form capable of direction manipulation,
The steering system, characterized in that the fine control unit is provided in the form of a button on the basic operation unit. The method of claim 1,
It further includes; an angle sensor for sensing a steering angle according to manipulation of the basic manipulation unit;
A steering system characterized in that a basic steering angle is calculated in relation to the steering angle and vehicle speed. The method of claim 1,
Further comprising a force sensor for detecting a force sensing value with respect to the manipulation direction of the basic manipulation unit,
A steering system according to claim 1 , wherein a fine steering angle is calculated in relation to an on-time of the fine manipulation unit, a force sensing value, and a vehicle speed. The method of claim 4,
The steering system, characterized in that the fine steering angle calculation is activated when the absolute value of the force sensing value exceeds a threshold value in the on-manipulation state of the fine manipulation unit. The method of claim 4,
The steering system according to claim 1, wherein the fine steering angle is determined in proportion to an ON operation holding time of the fine manipulation unit. The method of claim 4,
The steering system characterized in that, when the micro-control unit is turned on, the micro-steering angle gradually increases according to a set increase rate for a time during which the control is maintained. The method of claim 4,
The steering system, characterized in that the fine steering angle is gradually reduced according to the set reduction rate when the fine control unit is turned off. The method of claim 1,
The steering system characterized in that when it is determined that the operation of the basic steering angle is impossible, the final steering angle is calculated in relation to the fine steering angle and vehicle speed. calculating, by a steering angle control unit, a basic steering angle based on an operating state of a basic steering unit operated for basic steering of a wheel;
calculating, by a steering angle control unit, a fine steering angle based on a manipulation state of a fine manipulation unit in which a wheel is manipulated for fine steering;
A steering angle control unit calculating a final steering angle by summing the basic steering angle and the fine steering angle, and controlling the steering to steer the wheel with the final steering angle.

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