KR20230070715A - Apparatus for controlling motor driven power steering apparatus and method thereof - Google Patents

Abstract

Disclosed are a control device of an electric steering apparatus and a method thereof. The control device of the electric steering apparatus of the present invention comprises: a steering angle accumulation unit which accumulates a command steering angle output from an autonomous driving module; a change amount prediction unit which predicts a steering angle change amount by reflecting a steering angular velocity and a vehicle speed from the command steering angle accumulated in the steering angle accumulation unit; and a position control unit which outputs a final steering angle by adjusting position control gain for the command steering angle based on the steering angle change amount and the vehicle speed predicted by the change amount prediction unit. An objective of the present invention is to provide the control device of the electric steering apparatus, which adjusts control responsiveness of a position controller, and the method thereof.

Description

Control device and method of electric power steering device {APPARATUS FOR CONTROLLING MOTOR DRIVEN POWER STEERING APPARATUS AND METHOD THEREOF}

The present invention relates to a control device and method for an electric power steering device, and more particularly, to a steering angle change amount when fine steering correction is required due to left and right shaking of a vehicle during straight or gentle turning steering with a small steering range during autonomous driving. It relates to a control device and method for an electric power steering device that adjusts the control responsiveness of a position controller by predicting in advance.

With the development of automobile technology, it is expected that the spread of self-driving vehicles that can operate on their own without driver's control will rapidly advance. These autonomous vehicles control various sensors and control systems with artificial intelligence to drive themselves say possible cars.

In addition, autonomous vehicles not only prevent accidents caused by careless mistakes of drivers or aggressive driving, but also have the advantage that unlicensed, blind, and minors can freely use vehicles. In particular, regarding the safety of autonomous vehicles, A lot of research is being done. For example, when a vehicle is switched (or transitioned) from an autonomous driving mode to a manual mode in which the driver directly manipulates the vehicle, a lot of research is being conducted related to a technology for stably switching the right to control the vehicle to the driver.

However, research in the field of enabling an autonomous vehicle to maintain a sense of stability (e.g., anxiety or distrust in autonomous driving may occur if the sense of stability is reduced) to the user during autonomous driving mode operation is insufficient.

For example, as the driving speed of an autonomous vehicle changes (eg, driving speed changes from low speed to high speed or from high speed to low speed) during autonomous driving mode operation, for control of the motor driven power steering (MDPS) There is a problem in that a feeling of heterogeneity occurs when an operation mode (or MDPS control mode) transitions.

For example, when the driving speed of the vehicle changes from low speed to high speed (or from high speed to low speed), the operation mode for MDPS control is also changed from position control mode to torque control mode (or from torque control mode to position control mode). There is a problem in that an output difference occurs in an intermediate process in which an operation mode for controlling an electric steering device is changed.

In this way, when an output difference occurs in the middle process of changing the operation mode for controlling the electric steering device, there is a problem in that the occupant feels insecure (ie, the sense of stability is reduced).

The background art of the present invention is disclosed in Korean Patent Registration No. 10-1779823 (registered on September 13, 2017, method for switching control mode of autonomous vehicle and its device).

In addition to the control mode conversion mentioned above, fine left and right command steering angles are applied to the electric steering system (MDPS or EPS) when the steering range is small during autonomous driving, that is, straight driving or gentle turning driving.

In fact, when driving straight or gently turning during autonomous driving, the steering angle of the vehicle must be maintained. It shakes rapidly, so the error of the position controller occurs the same. At this time, the electric steering system is also corrected through position control, but the autonomous driving module also controls each other by receiving the steering angle of the electric steering system received as feedback. The control of the electric steering system may become unstable and a sense of difference may be given to the occupants.

In this way, in the autonomous driving system, when a finely small correction command steering angle is applied to the electric steering device for straight driving or gentle turning driving, in reality, not only does the control not work well, but also reverse control occurs because they do not sync with each other. There is a problem that often causes control instability.

Therefore, in order to solve this problem, there are many proposals such as obtaining the change in the command steering angle based on the currently received command steering angle and lowering the controller gain only when the change amount is small, but these methods have a problem in that immediate control response is impossible.

That is, when a quick steering change is made in the next step, the previously lowered gain setting state cannot be changed instantaneously, so there is a problem in that responsiveness may deteriorate during a control operation requiring a quick response.

The present invention has been made to improve the above problems, and an object of the present invention according to one aspect is to require fine steering correction due to left and right shaking of the vehicle during straight or gentle turning steering with a small steering range during autonomous driving. To provide a control device and method for an electric power steering device that adjusts the control responsiveness of a position controller by predicting the amount of steering angle change in advance in case of an emergency.

A control apparatus for an electric steering apparatus according to an aspect of the present invention includes a steering angle accumulator for accumulating command steering angles output from an autonomous driving module; a change amount prediction unit that predicts a steering angle change amount by reflecting the steering angle speed and vehicle speed from the command steering angle accumulated in the steering angle accumulator; and a position control unit configured to output a final steering angle by adjusting a position control gain for the command steering angle based on the steering angle change amount and vehicle speed predicted by the change amount prediction unit.

In the present invention, the variation prediction unit derives a simultaneous equation through randomly extracted data from the accumulated values accumulated in the steering angle accumulator, sets a critical range based on the steering angle speed and vehicle speed in the derived simultaneous equation, and then includes it within the critical range. It is characterized in that the amount of steering angle change is predicted by repeatedly deriving simultaneous equations to have a set probability by extracting the number of data to be determined.

In the present invention, the variation prediction unit is characterized in that the threshold range is set wider as the steering angular velocity increases with respect to the y-axis in the simultaneous equation, and the threshold range is set narrower as the vehicle speed increases.

In the present invention, the variation prediction unit is characterized in that the higher the vehicle speed, the higher the probability is set.

In the present invention, the variation prediction unit is characterized in predicting the steering angle variation with the slope of the final simultaneous equations repeatedly derived.

In the present invention, the position controller lowers the position control gain as the vehicle speed is high and the steering angle change amount is low through a two-dimensional table map of vehicle speed and steering angle change amount.

A control method of an electric steering device according to another aspect of the present invention includes accumulating a steering angle command output from an autonomous driving module by a steering angle accumulator of the electric steering device; predicting a steering angle change by a change estimation unit by reflecting the steering angular velocity and the vehicle speed from the command steering angle accumulated in the steering angle accumulation unit; adjusting, by a position control unit, a position control gain for a command steering angle based on a steering angle change amount and a vehicle speed predicted by a change amount prediction unit; and outputting, by the position control unit, a final steering angle by applying a position control gain to the steering angle command output from the autonomous driving module.

In the present invention, the step of estimating the amount of steering angle change may include deriving a simultaneous equation through data randomly extracted from the accumulated value accumulated in the steering angle accumulator by the change amount prediction unit; Setting a critical range based on the steering angular velocity and the vehicle speed in the derived simultaneous equations; extracting the number of data included in the threshold range; Deriving a final system of equations by repeating the above process so that the number of extracted data has a set probability; and estimating a steering angle variation based on the gradient of the final system of equations.

In the step of setting the threshold range in the present invention, the variation prediction unit sets the threshold range wider as the steering angular speed increases with respect to the y-axis in the simultaneous equation, and sets the threshold range narrower as the vehicle speed increases.

In the step of deriving the final simultaneous equations in the present invention, the variation predictor sets a higher probability as the vehicle speed increases.

In the step of outputting the final steering angle in the present invention, the location control unit lowers the position control gain as the vehicle speed is high and the steering angle change amount is low through a two-dimensional table map of vehicle speed and steering angle change amount.

An electric steering control apparatus and method according to an aspect of the present invention predicts the amount of change in steering angle in advance when fine steering correction is required due to left and right shaking of a vehicle during straight or gentle turning steering with a small steering range during autonomous driving. By adjusting the control responsiveness of the position controller, it is possible to improve the vehicle's behavior and steering heterogeneity through smooth steering.

1 is a block configuration diagram showing a control device for an electric power steering device according to an embodiment of the present invention.
2 is a flowchart illustrating a control method of an electric power steering apparatus according to an embodiment of the present invention.

Hereinafter, a control device and method for an electric power steering device according to the present invention will be described with reference to the accompanying drawings. In this process, the thickness of lines or the size of components shown in the drawings may be exaggerated for clarity and convenience of explanation. 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 a user or operator. Therefore, definitions of these terms will have to be made based on the content throughout this specification.

1 is a block configuration diagram showing a control device for an electric power steering device according to an embodiment of the present invention.

As shown in FIG. 1 , a control device for an electric steering apparatus according to an embodiment of the present invention may include a steering angle accumulator 20 , a variation estimation unit 30 and a position control unit 40 .

The steering angle accumulator 20 may accumulate command steering angles output from the autonomous driving module 10 .

At this time, the command steering angle output from the autonomous driving module 10 is also output to the position control unit 40 at the same time.

The change amount prediction unit 30 may estimate the steering angle change amount by reflecting the steering angle speed and vehicle speed from the command steering angle accumulated by the steering angle accumulator 20 for a set time.

Here, the change amount predictor 30 randomly extracts two or more pieces of data from the accumulated value accumulated for a set time in the steering angle accumulator 20 and then derives a simultaneous equation through the extracted data.

Then, a critical range is set based on the steering angular velocity and vehicle speed in the derived system of equations, and the number of data included in the critical range is extracted.

Here, the threshold range may be set wider as the steering angular speed increases based on the steering angle of the y-axis, and narrower as the vehicle speed increases.

That is, when the threshold range is set wide, data with a large steering angle variation is extracted, and when the threshold range is set narrowly, data with a small steering angle variation is extracted.

The variation prediction unit 30 repeats the process of extracting the number of data included in the critical range by extracting random data, deriving a simultaneous equation, and repeating the process of extracting the number of data included in the critical range until the number of data extracted in this way satisfies the set probability. derive the equation

Here, the probability may be set higher as the vehicle speed increases. That is, when the vehicle speed is high, the probability is increased to increase stability.

After deriving the final system of equations in this way, the amount of steering angle change can be predicted by the slope of the final system of equations.

The position control unit 40 adjusts and sets the position control gain for the command steering angle based on the steering angle change amount and vehicle speed predicted by the change amount predictor 30, and sets the set position control gain as a command output from the autonomous driving module 10. Position control can be performed by outputting the final steering angle by applying it to the steering angle.

That is, the position control unit 40 may lower the position control gain as the vehicle speed is high and the steering angle change amount is low through a two-dimensional table map of vehicle speed and steering angle change amount.

When the steering angle change in the position control unit 40 is low or the vehicle speed is high, in a situation where sensitive control is unnecessary, that is, a smooth driving feeling can be provided by varying the position control gain through a previously predicted driving path or command steering change.

For example, in situations where left and right fine correction is not required, such as straight driving or turning driving, the responsiveness of position control is slightly lowered to adjust the control responsiveness to the command steering angle, so that the vehicle can be controlled in the lateral direction smoothly. can

As described above, according to the control device of the electric steering device according to the embodiment of the present invention, steering angle change amount when fine steering correction is required due to left and right shaking of the vehicle during straight driving with a small steering range or gentle turning steering driving during autonomous driving. By predicting in advance and adjusting the control responsiveness of the position controller, it is possible to improve the vehicle's behavior and steering heterogeneity through smooth steering.

2 is a flowchart illustrating a control method of an electric power steering apparatus according to an embodiment of the present invention.

As shown in FIG. 2 , in the control method of the electric steering device according to an embodiment of the present invention, first, the steering angle accumulator 20 of the electric steering device accumulates the command steering angle output from the autonomous driving module 10 ( S10).

Here, the command steering angle output from the autonomous driving module 10 is simultaneously output to the steering angle accumulator 20 and the position control unit 40 .

When the set time command steering angle is accumulated in the steering angle accumulator 20 in step S10, the variation predictor 30 predicts the steering angle change by reflecting the steering angle speed and vehicle speed from the command steering angle accumulated in the steering angle accumulator 20 ( S30).

Here, the change amount predictor 30 randomly extracts two or more pieces of data from the accumulated value accumulated for a set time in the steering angle accumulator 20 and then derives a simultaneous equation through the extracted data.

Then, a critical range is set based on the steering angular velocity and vehicle speed in the derived system of equations, and the number of data included in the critical range is extracted.

Here, the threshold range may be set wider as the steering angular speed increases based on the steering angle of the y-axis, and narrower as the vehicle speed increases.

That is, when the threshold range is set wide, data with a large steering angle variation is extracted, and when the threshold range is set narrowly, data with a small steering angle variation is extracted.

Thereafter, the variation prediction unit 30 repeats the process of extracting the number of data included in the critical range by extracting random data, deriving a simultaneous equation, and extracting the number of data included in the critical range until the number of data extracted in this way satisfies the set probability. Derive a system of equations.

Here, the probability may be set higher as the vehicle speed increases. That is, when the vehicle speed is high, the probability is increased to increase stability.

After deriving the final system of equations in this way, the amount of steering angle change can be predicted by the slope of the final system of equations.

If the steering angle change amount is predicted in step S20, the position control unit 40 adjusts and sets the position control gain for the command steering angle based on the steering angle change amount predicted by the change amount predictor 30 and the vehicle speed (S30).

After setting the position control gain for the command steering angle based on the steering angle change amount and vehicle speed predicted in step S30, the position control unit 40 applies the position control gain to the command steering angle output from the autonomous driving module 10 to determine the final steering angle. It outputs and performs position control (S40).

That is, the position control unit 40 may lower the position control gain as the vehicle speed is high and the steering angle change amount is low through a two-dimensional table map of vehicle speed and steering angle change amount.

When the steering angle change in the position control unit 40 is low or the vehicle speed is high, in a situation where sensitive control is unnecessary, that is, a smooth driving feeling can be provided by varying the position control gain through a previously predicted driving path or command steering change.

For example, in situations where left and right fine correction is not required, such as straight driving or turning driving, the responsiveness of position control is slightly lowered to adjust the control responsiveness to the command steering angle, so that the vehicle can be controlled in the lateral direction smoothly. can

As described above, according to the control method of the electric steering device according to an embodiment of the present invention, steering angle change amount when fine steering correction is required due to left and right shaking of the vehicle during straight driving with a small steering range or gentle turning steering during autonomous driving. By predicting in advance and adjusting the control responsiveness of the position controller, it is possible to improve the vehicle's behavior and steering heterogeneity through smooth steering.

Implementations described herein may be embodied in, for example, a method or process, an apparatus, a software program, a data stream, or a signal. Even if discussed only in the context of a single form of implementation (eg, discussed only as a method), the implementation of features discussed may also be implemented in other forms (eg, an apparatus or program). The device may be implemented in suitable hardware, software and firmware. The method may be implemented in an apparatus such as a processor, which is generally referred to as a processing device including, for example, a computer, microprocessor, integrated circuit, 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.

The present invention has been described with reference to the embodiments shown in the drawings, but this is only exemplary, and those skilled in the art can make various modifications and equivalent other embodiments. will understand

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

10: autonomous driving module
20: steering angle accumulator
30: change amount prediction unit
40: position control

Claims (11)

a steering angle accumulator for accumulating command steering angles output from the autonomous driving module;
a change estimation unit for estimating a steering angle change amount by reflecting the steering angular velocity and vehicle speed from the command steering angle accumulated in the steering angle accumulator; and
and a position control unit configured to output a final steering angle by adjusting a position control gain for the command steering angle based on the steering angle change amount and vehicle speed predicted by the variation prediction unit.
The method of claim 1 , wherein the change prediction unit derives a simultaneous equation through data randomly extracted from the accumulated values accumulated in the steering angle accumulator, and sets a critical range based on the steering angle speed and vehicle speed in the derived simultaneous equation. and then extracting the number of data included in the critical range and repeatedly deriving simultaneous equations to have a set probability to predict the amount of steering angle change.
3. The electric power steering according to claim 2, wherein the variation prediction unit sets the threshold range wider as the steering angular speed increases with respect to the y-axis in the simultaneous equation, and sets the threshold range narrower as the vehicle speed increases. device controls.
The control device of claim 2 , wherein the variation prediction unit sets the probability higher as the vehicle speed increases.
The control device of claim 2, wherein the change amount prediction unit predicts the steering angle change amount using a slope of a final simultaneous equation repeatedly derived.
4. The control of the electric steering apparatus according to claim 1 , wherein the position control unit lowers the position control gain as the vehicle speed is higher and the steering angle change amount is lower, through a two-dimensional table map of the vehicle speed and the steering angle change amount. Device.
Accumulating a steering angle command output from an autonomous driving module by a steering angle accumulator of an electric power steering device;
predicting a steering angle change by a change estimation unit by reflecting the steering angular velocity and vehicle speed from the command steering angle accumulated in the steering angle accumulator;
adjusting, by a position controller, a position control gain for the command steering angle based on the steering angle variation predicted by the variation predictor and the vehicle speed; and
and outputting, by the position control unit, a final steering angle by applying the position control gain to the command steering angle output from the autonomous driving module.
The method of claim 7, wherein the step of estimating the amount of steering angle change comprises:
deriving a simultaneous equation through the data randomly extracted from the accumulated values accumulated in the steering angle accumulator by the variation prediction unit;
setting a threshold range based on the steering angular velocity and the vehicle speed in the derived simultaneous equations;
extracting the number of data included in the threshold range;
Deriving a final system of equations by repeating the above process so that the number of extracted data has a set probability; and
The control method of an electric power steering device comprising the; step of estimating the amount of steering angle change based on the gradient of the final simultaneous equation.
9. The method of claim 8 , wherein the step of setting the threshold range comprises: the variation predictor sets the threshold range wider as the steering angular velocity increases with respect to the y-axis in the simultaneous equation, and narrows the threshold range as the vehicle speed increases A control method of an electric power steering device, characterized in that for setting.
The control method of claim 8 , wherein, in the step of deriving the final simultaneous equation, the variation predictor sets a higher probability as the vehicle speed increases.
The method of claim 7 , wherein the outputting of the final steering angle comprises: the location control unit lowering the position control gain as the vehicle speed is high and the steering angle change amount is low, through a two-dimensional table map of the vehicle speed and the steering angle change amount. A control method for an electric power steering system characterized by

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