KR101998368B1 - Method and apparatus for controlling electric motor of electric assist steering system - Google Patents

Abstract

A method of calculating a steering assist torque for controlling a motor of an electric assist steering system includes generating a low frequency torque signal from an applied steering torque signal using a low pass filter, calculating a low frequency assist torque based on the low frequency torque signal Generating a relative high frequency torque signal using the applied steering torque signal and the low frequency torque signal; generating a high frequency torque signal from the relative high frequency torque signal using a high pass filter; Frequency assist torque, and calculating the steering assist torque by the sum of the low-frequency assist torque and the high-frequency assist torque. Wherein the high-pass filter includes a plurality of high-pass filters divided in accordance with a steering angle section, and the relative high-frequency torque signal is selectively distributed to any one of the plurality of high-pass filters according to a magnitude of a steering angle at the time, A high frequency torque signal is generated.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electric assist steering system,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control method of a motor-assisted steering system of a vehicle, and more particularly to a determination of a high-frequency assist component for motor control.

BACKGROUND ART An electric assist steering system is a device that provides a steering assist torque that assists a steering force of a driver by utilizing the force of an electric motor, and is recently widely used in a steering apparatus of a vehicle.

The electric assist steering system includes various algorithms for determining the steering assist torque, and determines a proper steering assist torque based on the parameters such as the steering torque inputted by the driver and the vehicle speed, and accordingly generates a voltage signal .

Typically, the steering torque is divided into a low-frequency steering torque and a high-frequency steering torque by a predetermined cut-off frequency according to the vehicle speed, and a low-frequency steering torque and a high-frequency steering torque are divided into a low- Frequency assist torque and the high-frequency assist torque. The output of the assist torque is determined by adding the high frequency assist torque to the low frequency assist torque. At this time, the low frequency assist torque forms the main output determining the steering assist according to the speed of the vehicle, and the high frequency assist torque is related to the response of the system, so that the responsiveness of the system is enhanced at the time of steep steering or sudden cornering, Allows you to maintain a sense of steering. Here, the high frequency assist torque is calculated by amplifying by the high frequency steering torque and the high frequency assist gain, and the high frequency assist gain is usually determined by the vehicle speed and the input frequency magnitude.

The steering feel, responsiveness, and stability in the on-center area, ie, in the middle of the 15-degree range of steering angle, for example, correspond to the basic performance index of the steering system. Are also very important indicators that are related. However, according to the conventional assist torque calculating method, in the high-frequency assist torque calculation, it is separately processed in a manner of processing into lower logic in the assist torque logic in the on-center region or in a manner of determining the degree of amplification or attenuation with a specific gain. With such a conventional method, fine tuning is difficult in the on-center area.

U.S. Published patent application US2010 / 0198461 (published on Aug. 05, 2010)

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a steering assist torque control method capable of finely and accurately adjusting a steering assist in an on-center region.

A motor control method for controlling a motor of an electric assist steering system according to an embodiment of the present invention includes generating a low frequency torque signal by a low pass filter using a sensed applied steering torque signal and a vehicle speed, Generating a relative high frequency torque signal by using the applied steering torque signal and the low frequency torque signal, and outputting the relative high frequency torque signal to the high pass filter using the relative high frequency torque signal and the vehicle speed, Generating a high frequency assist torque signal by using the high frequency torque signal and the vehicle speed; generating a torque command signal by using a sum of the low frequency assist torque signal and the high frequency assist torque signal; Step, and the torque command And generating an output signal for driving the motor using a signal. Wherein the high-pass filter includes a plurality of high-pass filters divided in accordance with a steering angle section, and the relative high-frequency torque signal is selectively distributed to any one of the plurality of high-pass filters according to a magnitude of a steering angle at the time, A high frequency torque signal is generated.

The high pass filter may be configured to generate the high frequency torque signal using a cutoff frequency set for each of a plurality of steering angle sections and a plurality of vehicle speed sections.

The high-pass filter may include an on-center section high-pass filter, a transition section high-pass filter, and an off-center section high-pass filter divided according to a steering angle section, And an off-center period, and a vehicle speed section including a low speed section, a middle speed section, and a high speed section.

In the step of generating the high frequency assist torque, the high frequency assist torque signal may be calculated using a high frequency assist gain set for each of a plurality of steering angle sections and a plurality of vehicle speed sections.

The high frequency assist gain may be set according to a section of the steering angle consisting of an on-center section, a transition section, and an off-center section, and a section of a vehicle speed including a low speed section, a middle speed section and a high speed section.

A motor control apparatus for controlling a motor of an electric assist steering system according to an embodiment of the present invention includes a torque sensor for sensing an applied steering torque signal indicative of an applied steering torque and a torque sensor for detecting an applied steering torque signal and a low frequency torque signal A low frequency assist circuit for generating a low frequency assist torque signal by using the low frequency torque signal and the vehicle speed, a low frequency assist circuit for generating a low frequency torque signal by using the low frequency torque signal and the low frequency torque signal, A high frequency assist circuit for generating a high frequency torque signal by using the high frequency torque signal and the vehicle speed, a high frequency assist circuit for generating a high frequency assist torque signal by using the high frequency torque signal and the vehicle speed, Sat Signal and a summing amplifier for generating a torque assist signal by adding the high frequency assist torque signal, and includes a variable notch filter for generating a torque command signal with the torque assist signal. Wherein the high-pass filter includes a plurality of high-pass filters divided in accordance with a steering angle section, and the relative high-frequency torque signal is selectively distributed to any one of the plurality of high-pass filters according to a magnitude of a steering angle at the time, A high frequency torque signal is generated.

Meanwhile, a method for calculating a steering assist torque for controlling a motor of an electric power assist steering system according to an embodiment of the present invention includes generating a low frequency torque signal from an applied steering torque signal using a low pass filter, Generating a relative high frequency torque signal using the applied steering torque signal and the low frequency torque signal, generating a high frequency torque signal from the relative high frequency torque signal using a high pass filter, calculating a low frequency assist torque based on the relative high frequency torque signal, Calculating a high frequency assist torque based on the high frequency torque signal, and calculating a steering assist torque by a sum of the low frequency assist torque and the high frequency assist torque. Wherein the high-pass filter includes a plurality of high-pass filters divided in accordance with a steering angle section, and the relative high-frequency torque signal is selectively distributed to any one of the plurality of high-pass filters according to a magnitude of a steering angle at the time, A high frequency torque signal is generated.

The high pass filter may be configured to generate the high frequency torque signal using a cutoff frequency set for each of a plurality of steering angle sections and a plurality of vehicle speed sections.

The high-pass filter may include an on-center section high-pass filter, a transition section high-pass filter, and an off-center section high-pass filter divided according to a steering angle section, And an off-center period, and a vehicle speed section including a low speed section, a middle speed section, and a high speed section.

In the step of generating the high frequency assist torque, the high frequency assist torque signal may be calculated using a high frequency assist gain set for each of a plurality of steering angle sections and a plurality of vehicle speed sections.

The high frequency assist gain may be set according to a section of the steering angle consisting of an on-center section, a transition section, and an off-center section, and a section of a vehicle speed including a low speed section, a middle speed section and a high speed section.

An apparatus for calculating a steering assist torque for controlling a motor of an electric power assist steering system according to an embodiment of the present invention includes a low pass filter for generating a low frequency torque signal from an applied steering torque signal and a low frequency assist torque generator for generating a low frequency assist torque based on the low frequency torque signal, A relative high frequency torque signal calculation circuit for generating a relative high frequency torque signal using the applied steering torque signal and the low frequency torque signal, a high pass filter for generating a high frequency torque signal from the relative high frequency torque signal, A high frequency assist circuit for calculating a high frequency assist torque based on the high frequency torque signal and a summation circuit for calculating a steering assist torque by a sum of the low frequency assist torque and the high frequency assist torque. Wherein the high-pass filter includes a plurality of high-pass filters divided in accordance with a steering angle section, and the relative high-frequency torque signal is selectively distributed to any one of the plurality of high-pass filters according to a magnitude of a steering angle at the time, A high frequency torque signal is generated.

According to the present invention, the high-pass filter is composed of a plurality of high-pass filters divided by the vehicle speed section and the cut-off frequency for extracting the high-frequency components is also determined for each vehicle speed section and the steering angle section, .

1 is a schematic view of a motor-assisted steering system to which a motor control method according to an embodiment of the present invention can be applied.
2 is a diagram showing a torque control algorithm in the motor control method of the electric motor assisted steering system according to the embodiment of the present invention.
3 is a diagram illustrating an example of a cutoff frequency table used in a motor control method according to an embodiment of the present invention.
4 is a diagram illustrating an example of a high-frequency gain table used in a motor control method according to an embodiment of the present invention.

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

Referring to FIG. 1, the electric assist steering system 10 includes a steering wheel 12 connected to an input steering shaft 11. The input steering shaft 11 may be connected to the output steering shaft 14 via a torsion bar 13. The steering torque applied through the steering wheel 12 is transmitted to the output steering shaft 14 through the input steering shaft 11 and the torsion bar 13 and the torsion bar 13 is transmitted to the input steering shaft 11 and the output shaft 12. [ And is formed so as to be twisted corresponding to the rotation of the steering wheel 12 so that relative rotation of the steering shaft 14 is possible.

The position sensor 15 detects the relative rotational position between the input steering shaft 11 and the output steering shaft 14. [ The position sensor 15 forms a torque sensor 20 together with the torsion bar 13. The torque sensor 20 transmits an applied torque signal t _app to the torque signal processor 21.

When the steering wheel 12 is rotated, the relative rotation angle between the input steering shaft 11 and the output steering shaft 14 changes in accordance with the input torque applied to the steering wheel 12. [ The torque signal processor 21 monitors the relative rotation angle between the input steering shaft 11 and the output steering shaft 14 through the input torque signal and detects the relative rotation angle between the applied torque signal t _app and the physical characteristics of the torsion bar 13 (For example, a spring constant) is used to output the applied steering torque t _s .

The output steering shaft 14 can be connected to the pinion gear 31 constituting the steering gear box and the pinion gear 31 can be engaged with the rack gear of the rack bar 32. [ The pivotal movement of the wheel 33 connected thereto can be achieved by the lateral movement of the rack bar 32. [

An electric motor 40 for providing a steering assist may be connected to the rack bar 32 to provide a force for the left and right movement of the rack bar 32. The electric motor 40 may be connected to the rack bar 32 to transmit a force to the rack bar 32 in a manner known in the art. On the other hand, the electric motor 40 may be installed on the output steering shaft 14 instead of the rack bar 32 to provide the steering assist.

The electric motor 40 may be various types of motors known in the art. For example, the electric motor 40 may be a permanent magnet ac motor (PMAC motor), and the magnitude and direction of the current generated by the electric motor 40 may be determined by the magnitude and direction of the current applied to the rotor coil . Hereinafter, the case where the electric motor 40 is a permanent magnet AC motor will be described.

The rotor position sensor 50 senses the position of the rotor relative to the stator of the electric motor 40 and outputs a rotor position signal? That is a value indicative of the relative position between the rotor and the stator.

An electric assist steering system (10) according to an embodiment of the present invention includes an electronic control unit (ECU) (60). The ECU 60 may include a microprocessor, memory and associated hardware and software, and may be programmed to perform the steering assist logic described below.

The ECU 60 can be connected to the drive circuit 70 which is an electric circuit for driving the electric motor 40 and the drive circuit 70 can be connected to the vehicle power supply 71. [ The vehicle power supply 71 may include a battery, a power supply, a relay, and the like, and provides power for driving the electric motor 40. The ECU 60 provides the voltage output signal v _out to the drive circuit 70 and the drive circuit 70 outputs the motor current i _m by the voltage output signal v _out .

The voltage / current monitoring device 80 monitors the motor current i _m supplied to the electric motor 40 and outputs the measured motor current signal i _mea .

The vehicle speed sensor 91 provides the vehicle speed signal v indicative of the vehicle speed to the ECU 60 and other inputs for the steering assist control may be provided to the ECU 60. [

The ECU 60 may include a control algorithm for steering assist control and the control algorithm may include a torque control algorithm 61, a motor control algorithm 62 and a current control algorithm 63. The control algorithm may be implemented in software or in the form of an electrical circuit.

The torque control algorithm 61 outputs the demand torque command _tcmd . Required torque command signal (t _cmd) indicates the size of the steering assist torque required by the electric motor 40, the required torque command (t _cmd) is the sensed applied steering torque (t _s) and sensing the vehicle speed (v) . ≪ / RTI > The demand torque command (t _cmd ) is provided to the motor control algorithm 62.

The motor control algorithm 62 can determine the motor current command (i _cmd ) and the dq current advance angle (delta). The motor current command (i _cmd ) indicates the magnitude of the current to be supplied to the electric motor 40. The dq current advance angle (delta) represents the rotation angle of the motor current with respect to the q-axis on which the motor operates and can be determined as a function of the motor speed. The motor current command i _cmd and the dq current advance angle delta can be determined based on the required torque command t _cmd and the rotor speed ω calculated by the sensed rotor position θ. The measured motor current signal _imea and the sensed rotor position [theta] may be provided to the motor control algorithm 62 for feedback and monitoring purposes. The motor control algorithm 62 provides the motor current command (i _cmd ) and the dq current forward angle [delta] to the current control algorithm 63.

The current control algorithm 63 serves to determine the output voltage signal v _out . The output voltage signal v _out represents the voltage supplied to each phase of the PMAC electric motor 40 and is the sum of the motor current command i _cmd , the dq current forward angle delta and the sensed rotor position [theta] . ≪ / RTI > The measured motor current signal (i _mea ) may be supplied to motor control algorithm 62 and current control algorithm 63.

Hereinafter, an example of a method for determining the required torque command _tcmd will be described with reference to Fig. 2, the torque control algorithm 61 using the sensing and the sensed applied steering torque (t _s), vehicle speed (v) to produce a required torque command _(cmd t).

The sensed applied steering torque t _s is supplied to the low-pass filter 622. The low pass filter 622 may pass a component having a frequency smaller than the cutoff frequency? _CL among the detected steering torque signals and block the remaining signals. The cutoff frequency? _CL may be determined using a lookup table (cutoff frequency table) 6221 having cutoff frequency data according to the vehicle speed v, or may be determined by a predetermined equation as a function of the vehicle speed. The cut-off frequency may be set so as to gradually increase as the vehicle speed v increases.

The low-pass filter 622 generates a low-pass torque signal t _sL and supplies it to the low-frequency assist circuit 625. The low frequency assist circuit 625 generates a low frequency assist torque signal t _asLF having a value associated with the low pass torque signal t _sL and the sensed vehicle speed v.

On the other hand, a torque signal of a relatively high frequency band determined according to the cut-off frequency (? _CL ) of the low-pass filter 622 is obtained. For example, applied through a subtractor 621 by subtracting the steering torque (t _s), the low-pass torque signal (t _sL) can be obtained at a relatively high frequency torque (t _{sH _R).}

According to an embodiment of the invention, the high-pass filter (623) are composed of a plurality of high-pass filter (623a, 623b, 623c), a relatively high frequency torque (t _{sH _R)} is high through a de-multiplexer (demultiplexer) (624) Pass filters 623a, 623b, and 623c constituting the pass filter 623. The high pass filters 623a, 623b,

According to an embodiment of the invention, a low-pass filter 622, and obtain a relatively high-frequency component primarily through the subtracter 621 and passed through high-pass the relatively high frequency torque (t _{sH _R)} primarily obtained by the back filter 623 A high frequency component is obtained secondarily. Thus, in the embodiment of the present invention, extraction of a high-frequency component of a double structure occurs.

The high-pass filter 623 includes three high-pass filters, that is, an on-center section high-pass filter 623a, a transition section high-pass filter 623b, And an off-center section high-pass filter 623c. Here, the on-center section, the transition section, and the off-center section are arbitrarily classified according to the steering angle of the steering wheel according to the conditions required for the vehicle, and the on- And the off-center interval may mean an interval in which the steering wheel is out of the center range of 300 or 400 degrees, and the interval between the on-center interval and the off-center interval may be the normal It is called transition section.

On the de-multiplexer 624 is a relatively high frequency torque (t _{sH _R)} for the input and can be configured to work with the steering angle of the steering wheel in the distribution condition, a relatively high frequency torque (t _{sH _R)} in accordance with the steering wheel angle - A center section high-pass filter 623a, a transition section high-pass filter 623b, and an off-center section high-pass filter 623c.

On the other hand, the high-pass filter 623 passes a component having a frequency of a size greater than the cut-off frequency (ω _cH) of a relatively high frequency torque (t _{sH _R)} and the rest signal can be blocked. The cutoff frequency? _CH can be determined using a lookup table (cutoff frequency table) 6231 having cutoff frequency data according to the vehicle speed, and can be set to have a gradually increasing value as the vehicle speed v increases as a whole have. On the other hand, the cutoff frequency may be determined by a predetermined equation as a function of the vehicle speed.

3, the cutoff frequency table 6231 may include a cutoff frequency determined for each steering angle and for each of the vehicle speed sections. For example, the vehicle speed section may include three vehicle speed sections, that is, a low vehicle speed section, a middle vehicle speed section, and a low vehicle speed section, which are divided on the basis of two predetermined speeds (for example, 30 km / h and 80 km / h) And a high vehicle speed, and the steering angle section may be divided into three steering angle sections, i.e., an on-center section, a transition section, and an off-center section. In this way, the cut-off frequency table 6231 can be composed of cut-off frequency data determined for each of the vehicle speed section and the steering angle.

The relatively high frequency torque by (t _{sH _R)} is turned on according to the magnitude of the steering angle at that time by the de-multiplexer 624-center range a high-pass filter (623a), the transition period the high-pass filter (623b), and an off-center Pass filter _623c and the cut-off frequency determined from the cut-off frequency table 6231 is selected according to the size of the vehicle speed at that point of time and the high-pass-torque signal t _sH ) Is generated.

A high pass filter 623 produces a high-pass torque signal _(sH t) by using as input a relatively high frequency torque (t _{sH _R).} In the embodiment of the present invention, based on the fact that the degree of change in the response characteristic through the change of the gain is larger than the change in the response characteristic obtained by changing the degree of the input using the high-pass filter, By adopting a structure in which high frequency components are extracted, it is possible to change the response characteristic more finer and finer than the response change obtained by changing the gain. In particular, by applying a high-pass filter 623 in addition to the relative high-frequency component obtained by first applying the low-pass filter 622, the high-frequency component is applied to the low-frequency assist 623, It is possible to achieve a change in the fine response characteristic by changing the high frequency component without changing the characteristic of the high frequency component. According to the embodiment of the present invention, the high-pass filter 623 is divided into an on-center section high-pass filter 623a, a transition section high-pass filter 623b, and an off-center section high- Pass filter 623c, and the cut-off frequency is set for each of the steering angle section and the vehicle speed section, so that finer and accurate response tuning is possible.

Then, the high-frequency assist circuit 626 amplifies the high-pass torque signal t _sH by the high-frequency assist gain to generate the high-frequency assist torque signal t _asHF . Referring to FIG. 4, the high frequency assist gain table 6261 may include a high frequency assist gain determined for each steering angle and a vehicle speed section. For example, the vehicle speed section may include three vehicle speed sections, that is, a low vehicle speed section, a middle vehicle speed section, and a low vehicle speed section, which are divided on the basis of two predetermined speeds (for example, 30 km / h and 80 km / h) And a high vehicle speed, and the steering angle section may be divided into three steering angle sections, i.e., an on-center section, a transition section, and an off-center section. As described above, the high frequency assist gain table 6261 can be composed of high frequency assist gain data that is determined for each vehicle speed section and steering angle. According to the embodiment of the present invention, by setting the high frequency assist gain for each steering angle section and the vehicle speed section, different high frequency assist gains can be set according to the vehicle speed even within a specific steering angle section, Tuning is possible.

Then, the assist torque is calculated by the sum of the high frequency assist torque and the low frequency assist torque.

2, the summing circuit 627 calculates the assist torque signal t _as by summing the low frequency assist torque signal t _asLF and the high frequency assist torque signal t _asHF . The calculated torque assist signal t _as may be filtered by the variable notch filter 628 and calculated as the torque command signal t _cmd . For example, the variable notch filter 628 may be configured to variably remove a frequency component of a specific band according to the vehicle speed, and a known variable notch filter may be used.

Further, although not shown in FIG. 2, logic necessary for steering assist force control such as damping logic, friction logic, and return logic may be added to yield a final torque command signal.

While the present invention has been particularly shown and described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And all changes and modifications to the scope of the invention.

10: Electric assist steering system
11: input steering shaft
13: Torsion bar
14: Output steering shaft
15: Position sensor
20: Torque sensor
21: torque signal processor
40: Electric motor
60: ECU
91: vehicle speed sensor
61: Torque control algorithm
62: Motor control algorithm
63: Current control algorithm
621:
622: Low-pass filter
623: High pass filter
624: Demultiplexer
625: Low frequency assist circuit
626: High frequency assist circuit
627: summing circuit

Claims (20)

A motor control method for controlling a motor of an electric assist steering system,
Generating a low frequency torque signal by a low pass filter using the sensed applied steering torque signal and the vehicle speed,
Generating a low frequency assist torque signal using the low frequency torque signal and the vehicle speed,
Generating a relative high frequency torque signal using the applied steering torque signal and the low frequency torque signal;
Generating a high frequency torque signal by a high pass filter using the relative high frequency torque signal and the vehicle speed,
Generating a high frequency assist torque signal using the high frequency torque signal and the vehicle speed,
Generating a torque command signal using the sum of the low frequency assist torque signal and the high frequency assist torque signal, and
Generating an output signal for driving the motor using the torque command signal,
Wherein the high-pass filter includes a plurality of high-pass filters divided in accordance with a steering angle section, and the relative high-frequency torque signal is selectively distributed to any one of the plurality of high-pass filters according to a magnitude of a steering angle at the time, A high frequency torque signal is generated,
Wherein the high pass filter is configured to generate the high frequency torque signal using a cutoff frequency that is set differently for each of a plurality of steering angle sections and for a plurality of vehicle speed sections in each steering angle section
Motor control method. delete The method of claim 1,
Wherein the high-pass filter includes an on-center section high-pass filter, a transition section high-pass filter, and an off-center section high-pass filter divided according to a steering angle section,
Wherein the cut-off frequency is set according to a section of the steering angle consisting of an on-center section, a transition section, and an off-center section, and a section of a vehicle speed including a low speed section, a middle speed section and a high speed section. The method of claim 1,
Wherein the high frequency assist torque signal is calculated using a high frequency assist gain set for each of a plurality of steering angle sections and a plurality of vehicle speed sections in the step of generating the high frequency assist torque. 5. The method of claim 4,
Wherein the high frequency assist gain is set according to a section of a steering angle consisting of an on-center section, a transition section, and an off-center section, and a section of a vehicle speed comprising a low speed section, a middle speed section and a high speed section. A motor control apparatus for controlling a motor of a motor-assist steering system,
A torque sensor for sensing an applied steering torque signal indicative of an applied steering torque,
A low pass filter for generating a low frequency torque signal using the sensed applied steering torque signal and the vehicle speed,
A low frequency assist circuit for generating a low frequency assist torque signal using the low frequency torque signal and the vehicle speed,
A relative high-frequency torque signal calculation circuit for generating a relative high-frequency torque signal using the applied steering torque signal and the low-frequency torque signal,
A high pass filter for generating a high frequency torque signal using the relative high frequency torque signal and the vehicle speed,
A high frequency assist circuit for generating a high frequency assist torque signal using the high frequency torque signal and the vehicle speed,
A summer for summing the low frequency assist torque signal and the high frequency assist torque signal to generate a torque assist signal;
And a variable notch filter for generating a torque command signal using the torque assist signal,
Wherein the high-pass filter includes a plurality of high-pass filters divided in accordance with a steering angle section, and the relative high-frequency torque signal is selectively distributed to any one of the plurality of high-pass filters according to a magnitude of a steering angle at the time, A high frequency torque signal is generated,
Wherein the high pass filter is configured to generate the high frequency torque signal using a cutoff frequency that is set differently for each of a plurality of steering angle sections and for a plurality of vehicle speed sections in each steering angle section
Motor control device. delete The method of claim 6,
Wherein the high-pass filter includes an on-center section high-pass filter, a transition section high-pass filter, and an off-center section high-pass filter divided according to a steering angle section,
Wherein the cut-off frequency is set according to a section of the steering angle consisting of an on-center section, a transition section, and an off-center section, and a section of a vehicle speed including a low speed section, a middle speed section and a high speed section. The method of claim 6,
Wherein the high frequency assist circuit calculates the high frequency assist torque signal using a high frequency assist gain set for each of a plurality of steering angle sections and a plurality of vehicle speed sections. The method of claim 9,
Wherein the high frequency assist gain is set according to a section of the steering angle consisting of an on-center section, a transition section, and an off-center section, and a section of a vehicle speed including a low speed section, a middle speed section and a high speed section. A method for calculating a steering assist torque for controlling a motor of an electric assist steering system,
Generating a low frequency torque signal from the applied steering torque signal using a low pass filter,
Calculating a low frequency assist torque based on the low frequency torque signal,
Generating a relative high frequency torque signal using the applied steering torque signal and the low frequency torque signal;
Generating a high frequency torque signal from the relative high frequency torque signal using a high pass filter,
Calculating a high frequency assist torque based on the high frequency torque signal, and
And calculating a steering assist torque by a sum of the low-frequency assist torque and the high-frequency assist torque,
Wherein the high-pass filter includes a plurality of high-pass filters divided in accordance with a steering angle section, and the relative high-frequency torque signal is selectively distributed to any one of the plurality of high-pass filters according to a magnitude of a steering angle at the time, A high frequency torque signal is generated,
Wherein the high pass filter is configured to generate the high frequency torque signal using a cutoff frequency that is set differently for each of a plurality of steering angle sections and for a plurality of vehicle speed sections in each steering angle section
Method for calculating steering assist torque. delete 12. The method of claim 11,
Wherein the high-pass filter includes an on-center section high-pass filter, a transition section high-pass filter, and an off-center section high-pass filter divided according to a steering angle section,
Wherein the cutoff frequency is set in accordance with a section of the steering angle consisting of an on-center section, a transition section, and an off-center section, and a section of a vehicle speed including a low speed section, a middle speed section and a high speed section. 12. The method of claim 11,
Wherein the high frequency assist torque signal is calculated using a high frequency assist gain set for each of a plurality of steering angle sections and a plurality of vehicle speed sections in the step of generating the high frequency assist torque. The method of claim 14,
Wherein the high frequency assist gain is set in accordance with a steering angle section including an on-center section, a transition section, and an off-center section, and a vehicle speed section composed of a low speed section, a middle speed section and a high speed section. An apparatus for calculating a steering assist torque for controlling a motor of an electric assist steering system,
A low-pass filter for generating a low-frequency torque signal from the applied steering torque signal,
A low frequency assist torque circuit for calculating a low frequency assist torque based on the low frequency torque signal,
A relative high-frequency torque signal calculation circuit for generating a relative high-frequency torque signal using the applied steering torque signal and the low-frequency torque signal,
A high pass filter for generating a high frequency torque signal from the relative high frequency torque signal,
A high frequency assist circuit for calculating a high frequency assist torque based on the high frequency torque signal, and
And a summation circuit for calculating a steering assist torque by a sum of the low-frequency assist torque and the high-frequency assist torque,
Wherein the high-pass filter includes a plurality of high-pass filters divided in accordance with a steering angle section, and the relative high-frequency torque signal is selectively distributed to any one of the plurality of high-pass filters according to a magnitude of a steering angle at the time, A high frequency torque signal is generated,
Wherein the high pass filter is configured to generate the high frequency torque signal using a cutoff frequency that is set differently for each of a plurality of steering angle sections and for a plurality of vehicle speed sections in each steering angle section
Steering assist torque calculating device. delete 17. The method of claim 16,
Wherein the high-pass filter includes an on-center section high-pass filter, a transition section high-pass filter, and an off-center section high-pass filter divided according to a steering angle section,
Wherein the cutoff frequency is set in accordance with a steering angle section including an on-center section, a transition section, and an off-center section, and a vehicle speed section composed of a low speed section, a middle speed section and a high speed section. 17. The method of claim 16,
Wherein the high frequency assist circuit calculates the high frequency assist torque signal using a high frequency assist gain set for each of a plurality of steering angle sections and a plurality of vehicle speed sections. 20. The method of claim 19,
Wherein the high frequency assist gain is set according to a steering angle section including an on-center section, a transition section, and an off-center section, and a section corresponding to a vehicle speed section including a low speed section, a middle speed section and a high speed section.

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