KR101903585B1 - Apparatus and method for reducing noise of Electric Power Steering - Google Patents

Abstract

The present invention relates to an apparatus and method for reducing noises of an electric power steering apparatus, and more particularly, to an apparatus and method for reducing noise in an electric power steering system, which includes a noise information receiver for receiving steering information according to a steering input of a driver and operation information of a steering apparatus based on the steering information, A noise reduction unit that generates a noise reduction signal having a frequency that is less than a frequency band of the estimated noise and that is different from an amplitude difference between the noise and the noise, And a noise reduction signal transmitter for transmitting the noise reduction signal to the steering device.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a noise reduction apparatus and method for an electric power steering apparatus,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for noise reduction of an electric steering system, and more particularly, to an apparatus and method for artificially generating a noise reduction signal to reduce noise generated in a motor and a belt of a steering apparatus.

The electric steering system is a device for controlling the steering of a vehicle by using an electronic control device for a vehicle according to the steering intention of a driver. It detects a steering torque generated in response to an operation of a steering wheel of a driver, and, based on the detected steering torque, And controls the steering of the vehicle by outputting the driving current for driving the motor that provides the power.

Electronic power steering (EPS) can be classified into various types such as R-EPS (Rack type EPS), C-EPS (Column type EPS) and DP-EPS (Dual Pinion type EPS) depending on the type and position of the reducer There is a kind of noise, but different noise is generated for each electric power steering device depending on the design structure of the reducer and the reduction gear ratio.

The most unpleasant noise among the noise generated is the noise in the vehicle interior such as the zipper noise due to the structure of the motor and the decelerator. Such noise is a noise generated according to the design structure, I have.

In this way, in the steering system, a noise having a specific frequency that may cause an unpleasant feeling to the driver of the vehicle occurs. In order to improve the noise, the noise is changed by the change of the design structure or the noise transmission path is shielded. And there is a problem that a separate device for noise reduction is not provided in the steering apparatus.

Recently, a method of reducing life noise by applying white noise is used. White noise is a noise level that does not have a specific auditory pattern because it is a signal having a substantially constant frequency spectrum over a wide frequency range. These white noises are very easy to get used to the ears, so they do not interfere with the work, and they act to cover up the annoying background noise.

However, a noise reduction apparatus for reducing the noise of a steering apparatus having a narrow frequency range by applying the same principle as that of white noise to a vehicle has not been developed yet.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides an apparatus and method for noise reduction of an electric steering system that reduces noise in a vehicle that is uncomfortable to a driver.

And a noise reduction apparatus and method for artificially generating a noise reduction signal corresponding to the noise frequency by calculating a noise frequency of the electric power steering apparatus.

The problems to be solved by the present invention are not limited to the above-mentioned problems, and other matters not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a noise reduction apparatus for an electric power steering system, including a noise information receiver for receiving steering information according to a steering input of a driver and operation information of a steering apparatus based on the steering information, A noise reduction unit for estimating a noise frequency of the steering apparatus based on the information and the operation information, a noise reduction unit for estimating a noise reduction frequency of the noise reduction unit, And a noise reduction signal transmitter for transmitting the noise reduction signal to the steering apparatus.

According to another aspect of the present invention, there is provided a noise reduction method of an electric power steering apparatus including a noise information reception step of receiving steering information based on a steering input of a driver and operation information of a steering apparatus based on the steering information, A noise estimating step of analyzing and estimating a frequency of a noise of the steering apparatus based on the information, a noise generating step of generating a noise reducing signal having a frequency except for the estimated frequency band of the noise, And a noise reduction signal transmission step of transmitting the noise reduction signal to the steering apparatus.

According to the present invention, it is possible to provide convenience to the vehicle driver by reducing the noise of the electric power steering apparatus.

Further, since the noise reduction signal corresponding to the noise of the electric power steering apparatus is easily generated, the noise reduction effect can be minimized accurately and quickly.

1 is a block diagram of a noise reduction apparatus according to an embodiment of the present invention.
2 is a flowchart of a noise reduction method according to an embodiment of the present invention.
Fig. 3 is a component configuration diagram for a motor apparatus included in an electric steering system.
4 is a diagram showing an example of reducing the noise of the steering type steering apparatus in the noise reducing apparatus.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In the drawings, like reference numerals are used to denote like elements throughout the drawings, even if they are shown on different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the components from other components, and the terms do not limit the nature, order, order, or number of the components. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; intervening "or that each component may be" connected, "" coupled, "or " connected" through other components.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. As used herein, the terms "comprises" and / or "made of" means that a component, step, operation, and / or element may be embodied in one or more other components, steps, operations, and / And does not exclude the presence or addition thereof.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a block diagram of a noise reducing apparatus 100 according to an embodiment of the present invention, and FIG. 3 is a diagram illustrating a configuration of a motor apparatus 300 included in an electric steering system.

1, the noise reduction apparatus 100 of the electric power steering apparatus according to the present invention includes a noise information receiving unit 110 for receiving steering information according to a steering input of a driver and operation information of a steering apparatus based on the steering information, A noise estimating unit 120 for analyzing and estimating a noise frequency of the steering apparatus based on the steering information and the operation information, a frequency estimating unit 120 for estimating the noise frequency of the steering apparatus, A noise reduction signal generation unit 130 for generating a noise reduction signal and a noise reduction signal transmission unit 140 for transmitting the noise reduction signal to the steering apparatus.

The noise information storage unit 150 stores the noise reduction signal corresponding to the estimated noise frequency, and generates and stores data in which the steering information, the operation information, and the noise reduction signal corresponding thereto are mapped .

At this time, the noise reducing apparatus 100 may be installed in the space of the electric steering apparatus or adjacent to the electric steering apparatus.

The noise reduction signal generated by the noise reduction apparatus 100 is a signal having a substantially constant frequency spectrum in a wide frequency range, and is a sound wave having no specific auditory pattern. This noise reduction signal acts to cover the noise of the unfavorable narrow frequency band.

Specifically, the noise generated by the torque ripple of the motor among the noise generated in the electric power steering apparatus is the largest, and the frequency of the noise generated in the electric steering apparatus is proportional to the angular speed of the handle operated by the driver Therefore, the frequency range of the noise may be different depending on the steering angle speed input by the steering operation of the driver.

Referring to FIG. 3, the motor device 300 generally includes a motor pulley 301, a rotor core and magnet 302, a rotor shaft 303, A motor power terminal 305, a bearing 306 on the motor pulley 301 side, an electronic control unit (ECU) side bearing 307, a sensing magnet assembly (Sensing Magnet Assembly) 308, a bracket 309, an O-ring 310, and a housing 311. In the motor device 300, the remaining components except for the motor pulley 301 may be referred to as a " motor ".

This configuration of the motor device 300 as shown in FIG. 3 is only an example, and may vary depending on the function of the motor device 300 and the type of the electric type steering device to which the motor device 300 is mounted.

At this time, the steering information received by the noise information receiving unit 110 may include at least one of the steering torque, the steering angle, the steering angle speed, and the steering assist force of the steering apparatus.

The operation information relates to information generated by the operation of the motor 300 and the motor pulley 301 according to the steering information. The information includes a revolution number (rpm) of the motor 300 of the steering apparatus, And may include at least one of the number of slots of the motor 300, the number of the poles of the motor 300, and the number of pulleys of the belt (the number of the mountains of the motor pulley 301).

In this case, the steering information and the operation information may be information sensed by various sensors provided in the vehicle such as a torque sensor, a steering angle sensor, a vehicle speed sensor, a rotation sensor, and a vibration sensor.

The noise estimator 120 receives the steering information and the operation information from the noise information receiver 110 and calculates a complex of the number of rotations of the motor apparatus 300 and the number of slots, Or the number of pulleys of the motor pulley 301 is proportional to the noise frequency of the motor or the belt.

Specifically, when the noise frequency of the motor 300 is f _motor , the number of rotations of the motor is R _motor , When the number of poles of the motor referred to the N _p, of the motor the number of slots N _S, noise frequency of the motor 300 is f _motor = ((number of poles of the motor) / 2) * ((6 * (number of revolutions of the motor ) (rpm) / 60 [sec / min] That is, f _motor = (N _p / 2) * (R _motor / 20) (Hz)

For example, when the number of revolutions of the motor 300 is 1000 rpm and the number of poles of the motor 300 is 6, the noise frequency of the motor 300 according to the above formula is (6 * 1000 rmp) / 20 sec / min = 300 Hz. ≪ / RTI > That is, depending on the number of revolutions of the motor 300, 0.3 * R _motor It can be assumed that a noise having a frequency of (Hz) is generated in the motor 300 of the steering apparatus. Therefore, the formula for the calculated noise frequency, 0.3 * R _motor (Hz), the number of revolutions of the motor 300 operating in accordance with the steering input of the driver is set to R _motor The noise frequency can be accurately estimated and calculated. Therefore, the noise frequency band of the calculated motor 300 (0.3 * R _motor It is possible to generate the noise reduction signal so as to have a frequency other than the frequency (Hz).

The noise frequency of the _motor 300 is f _motor = (the number of slots of the motor) * (the number of rotations of the motor) rpm / 60 [sec / min] because various noise is generated in the steering apparatus due to the internal circuit imbalance. That is, f _motor = N _S * R _motor / Be represented by the formula 60 (Hz) and or f _motor = (the number of poles of the motor) * (number of revolutions of the motor) [rpm] / 60 [sec / min] In other words, f _motor = N _P * R _motor / 60 ( Hz). ≪ / RTI >

If the noise frequency of the _belt is f _belt and the number of pulleys is N _mp , the noise frequency of the _belt is f _belt = (number of pulley teeth of the belt) * (number of revolutions of the motor) rpm / 60 sec / min], that is, f _belt = N _mp * R _motor / 60 (Hz).

For example, when the number of revolutions of the motor 300 is 1000 rpm and the number of pulleys of the belt is 30, the noise frequency of the belt according to the above formula is (30 * 1000 rmp) / 60 sec / min = 500 Hz Can be estimated. Therefore, the noise reduction signal can be generated so as to have a frequency other than 500 Hz which is the noise frequency band of the belt calculated.

Therefore, by substituting the above-mentioned steering information and the operation information into the above-mentioned equations, and estimating and calculating the noise frequency value, the noise reduction signal for reducing the noise by the motor 200 and the belt can be easily Can be generated.

The noise reduction signal generation unit 130 can determine a frequency band and an amplitude of the noise reduction signal with respect to the noise frequency estimated and calculated by the noise estimation unit 120 and outputs the noise reduction signal to the frequency band of the noise reduction signal The torque value of the steering apparatus can be calculated.

Specifically, the noise reduction signal generating unit 130 determines the frequency band of the noise reduction signal so as to have a frequency other than the noise frequency band, and adjusts the noise reduction signal so that the difference between the amplitude and the noise frequency is equal to or less than a threshold value. Can be determined. In this case, a torque value proportional to the noise reduction signal can be calculated by inversely converting the determined noise reduction signal into a time-axis signal regardless of the phase.

The noise reduction signal transmission unit 140 may transmit the torque value calculated by the noise reduction signal generation unit 130 to the motor control unit of the steering apparatus so as to output the noise reduction signal from the steering apparatus.

At this time, the motor control unit controls the motor unit 300 by using the result obtained by summing the torque value received from the noise reduction signal transmitting unit 140 and the steering torque value generated according to the steering input of the driver, The noise reduction signal may be output from the motor device 300. [

Therefore, by outputting the noise reduction signal from the motor 300 of the steering system so that various noise of the steering system can not be recognized, the driver can reduce the unpleasant feeling due to the noise of the steering system.

The noise information storage unit 150 stores the noise frequency calculated based on the steering information and the operation information and stores the noise reduction signal corresponding to the noise frequency, A look-up table for the noise reduction signal corresponding to the operation information can be generated, and the steering information, the operation information, and the noise reduction signal can be mapped using the lookup table .

Therefore, by extracting the noise reduction signal data mapped to the steering information and operation information received through the noise information reception unit 110 from the noise information storage unit 150, The controller 130 can directly calculate the torque value of the noise reduction signal.

Therefore, the process of estimating and calculating the noise frequency owing to the mapped data stored in the noise information storage unit 150 is omitted, so that the calculation processing speed of the noise reduction apparatus 100 is improved and the calculation cost is reduced.

As described above, since the noise generated in the steering apparatus is accurately analyzed and estimated according to the steering information and the operation information, the noise reduction signal of the steering apparatus is also easily generated. Therefore, Of course, the computation cost can also be reduced.

2 is a flowchart of a noise reduction method according to an embodiment of the present invention.

A noise reduction method of an electric power steering apparatus according to the present invention includes a noise information reception step of receiving steering information according to a steering input of a driver and operation information of a steering apparatus based on the steering information, A noise reduction signal generation step of generating a noise reduction signal having a frequency except for the estimated frequency band of the noise and having a difference in amplitude between the noise and the noise is less than or equal to a threshold; And a noise reduction signal transmission step of transmitting the noise reduction signal to the steering apparatus.

Referring to FIG. 2, in the noise information receiving step, the steering information and the steering angle information from various sensors provided in the vehicle including a torque sensor, a steering angle sensor, a vehicle speed sensor, a rotation sensor, And receives the operation information (S200).

And estimating the noise by using the steering information and the operation information to calculate a product of the number of rotations of the motor and the number of slots of the motor, a product of the number of rotations of the motor and the number of poles of the motor, At least one of the product of the number of pulleys of the motor pulley and the number of pulleys of the motor pulley is proportional to the noise frequency of the motor or the belt at step S210.

Here, the noise frequency of the motor 300 is f _motor , the number of rotations of the motor is R _motor , The noise frequency of the _motor is f _motor = ((the number of poles of the motor) / 2) * ((6 * (the number of rotations of the motor)) when the number of poles of the motor is N _p and the number of slots of the motor N _s . [rpm] / 60 [sec / min] That is, f _motor = (N _p / 2) * (R _motor / 20) (Hz). For example, when the number of revolutions of the motor is 1000 rpm and the number of poles of the motor is 6, it is estimated that the noise frequency of the motor according to the formula can be 6 * 1000 rmp / 20 sec / min = 300 Hz can do.

Then, the frequency band of the noise reduction signal is determined so as to have a frequency other than the noise frequency band calculated in the noise reduction signal generation step (S220), and the noise reduction is performed so that the difference between the amplitude and the noise frequency is less than a threshold value The amplitude of the signal is determined.

That is, by determining the frequency and amplitude of the noise reduction signal, a waveform of the noise reduction signal having a frequency of a wide band is generated (S230).

In this case, it is possible to calculate the torque value of the steering apparatus with respect to the frequency band of the generated noise reduction signal. In S230, the noise reduction signal is inversely transformed into a time axis signal regardless of the phase (S230) A proportional torque value can be calculated (S250).

In the noise reduction signal transmission step, the torque value calculated to output the noise reduction signal in the steering apparatus is transmitted to the motor control unit of the steering apparatus in step S260.

The noise reduction signal may be output from the motor by using the result of summing the torque value received by the motor control unit and the steering torque value generated by the driver's steering input, have.

Fig. 4 is a diagram showing an example of reducing the noise of the steering type steering apparatus in the noise reduction apparatus 100. Fig.

4 (a) to 4 (c) are graphs showing amplitudes according to the frequencies of the motor noise 41 and the noise reduction signal 42. FIG.

4 (a) shows the steering information according to the steering input of the driver and the operation information of the steering apparatus based on the steering information from the noise information receiving unit 110, At least one of a product of the number of revolutions of the motor 300 and the number of slots, a product of the number of revolutions and the number of poles, or a product of the number of revolutions and the number of pulleys of the motor pulley 301, The frequency of the motor noise 41 is estimated and calculated using the frequency-proportional relation. At this time, as shown in (a), the motor noise 41 frequency has a narrow frequency band.

Referring to FIG. 4B, the noise reduction signal generating unit 130 generates a noise reduction signal 42 having a frequency other than the motor noise 41 frequency band estimated and calculated from the noise estimation unit 120 FIG. 4 (b) also shows the frequency graph of the generated noise reduction signal 42 and the frequency graph of the motor noise 41 together.

At this time, the amplitude of the noise reduction signal 42 is determined so that the difference between the amplitude of the noise reduction signal 42 and the amplitude of the motor noise 41 is equal to or less than the threshold value, thereby generating the waveform of the noise reduction signal 42. Then, the torque value of the steering apparatus for the frequency band of the noise reduction signal 42 is calculated and transmitted to the noise reduction signal transmission unit 140.

Then, the motor control unit of the steering apparatus controls the motor 300 by using the resultant sum of the torque value received from the noise reduction signal transmitting unit 140 and the steering torque value generated in accordance with the steering input of the driver, 300 to output the noise reduction signal 42.

At this time, as shown in the graph of FIG. 4 (c), the motor noise (41) and the noise reduction signal (42) output from the motor are combined to generate a sound wave having a constant amplitude in a wide frequency band. And the noise reduction signal 42 are combined, the driver of the vehicle can recognize that the noise 41 is reduced.

As described above, according to the present invention, it is possible to provide convenience to a vehicle driver by reducing the noise of the electric power steering apparatus and to easily generate a noise reduction signal corresponding to the noise of the electric power steering apparatus, Can be provided.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined by the appended claims. The embodiments of the present invention are not intended to limit the scope of the present invention but to limit the scope of the present invention.

100: Noise reduction device
110: Noise information reception unit 120: Noise estimation unit
130: Noise reduction signal generator 140: Noise reduction signal transmitter
150: Noise information storage unit
300: Motor device
41: motor noise 42: noise reduction signal

Claims (9)

A noise information receiver for receiving steering information according to a steering input of a driver and operation information of a steering apparatus based on the steering information;
A noise estimator for analyzing and estimating a noise frequency of the steering apparatus based on the steering information and the operation information;
A noise reduction signal generation unit for generating a noise reduction signal having a frequency except for the estimated frequency band of noise and having an amplitude difference between the noise and the noise being below a threshold value; And
A noise reduction signal transmitter for transmitting the noise reduction signal to the steering device; , ≪ / RTI &
Wherein the noise reduction signal generation unit comprises:
And determining the frequency band and the amplitude of the noise reduction signal with respect to the noise frequency and calculating the torque value of the steering apparatus with respect to the frequency band of the noise reduction signal.
The method according to claim 1,
A noise information storage unit for storing the noise reduction signal corresponding to the estimated noise frequency and generating and storing the data in which the steering information and the operation information are mapped to the noise reduction signal corresponding thereto; Further comprising: a noise reduction device for an electric steering system.
The method according to claim 1,
Wherein the steering information includes at least one of a steering torque, a steering angle, a steering angle velocity, and a steering assist force of the steering apparatus, and the operation information includes at least one of a motor rotation number, a motor slot number, a motor pole number, The noise reduction device comprising:
The method of claim 3,
The noise estimator may include:
Wherein at least one of a product of the number of rotations and the number of slots, a product of the number of rotations and the number of poles, or a product of the number of rotations and the number of pulleys is proportional to the noise frequency of the motor or the belt, Noise reduction device of electric steering system calculating frequency.
delete The method according to claim 1,
The noise reduction signal transmitter includes:
And transmits the torque value calculated so as to output the noise reduction signal to the motor control unit of the steering apparatus.
A noise information receiving step of receiving steering information according to a steering input of a driver and operation information of a steering apparatus based on the steering information;
A noise estimation step of analyzing and estimating a frequency of a noise of the steering apparatus based on the steering information and the operation information;
A noise reduction signal generation step of generating a noise reduction signal having a frequency excluding the estimated frequency band of the noise and having a difference in amplitude with the noise below a threshold value; And
A noise reduction signal transmission step of transmitting the noise reduction signal to the steering apparatus; , ≪ / RTI &
The noise reduction signal generation step may include:
And determining a frequency band and an amplitude of the noise reduction signal with respect to the noise frequency and calculating a torque value of the steering apparatus with respect to the frequency band of the noise reduction signal.
delete 8. The method of claim 7,
Wherein the noise reduction signal transmission step comprises:
And the torque value calculated to output the noise reduction signal in the steering apparatus is transmitted to the motor control unit of the steering apparatus.

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