JP2017165117A - Electric power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric power steering device that is able to carry out phase compensation matching a vehicle state and that is able to achieve steering feeling matching the vehicle state.SOLUTION: In an EPS 1 (Electric Power Steering device), a phase delay compensation control part 51 and a phase advancement compensation control part 53 select, according to a vehicle state, two phase compensation controls different from each other, which correspond to a vehicle state when external force is exerted to the vehicle and a vehicle state when external force is not exerted. As a result, phase compensation matching a vehicle state can be carried out, and steering feeling matching the vehicle state can be achieved.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electric power steering apparatus.

  Conventionally, in an electric power steering apparatus, stability of a steering system is ensured by performing phase advance compensation and phase delay compensation of a steering torque (see Patent Document 1 and Patent Document 2).

  Patent Document 1 discloses a map for changing the phase compensation coefficient K in accordance with the road surface μ and the vehicle speed, and discloses that the coefficient K is increased or decreased in accordance with the size of the road surface μ. Further, Patent Document 2 discloses that the phase of the output signal of the torque sensor is changed by the phase control element so that the gain is reduced in the frequency band higher than the set frequency as compared with the turning steering state during the return operation. ing.

Japanese Patent Laying-Open No. 2006-117223, FIG. 46, paragraph 0168 JP 2006-298040 A

By the way, when the vehicle performs fast follow-up steering while turning at a high G, due to phase delay compensation, the follow-up performance of the motor assist is lowered and insufficient assist occurs.
In order to improve the shortage of assist, it is necessary to reduce the phase delay compensation of the torque and increase the phase advance compensation. However, if there is too much torque phase advance compensation, the noise in the detection signal of the torque sensor during normal steering increases due to an increase in gain due to phase advance compensation, and the deterioration of the road information is a problem. It becomes.

Note that Patent Document 1 and Patent Document 2 do not disclose how to perform the above case.
An object of the present invention is to provide an electric power steering apparatus that can perform phase compensation suitable for a vehicle state and realize a steering feeling suitable for the vehicle state.

  In order to solve the above-described problems, an electric power steering apparatus according to the present invention includes a steering torque detection unit that detects a steering torque that acts on a steering system of a vehicle, an electric motor that provides auxiliary torque to the steering system, and the steering torque. A phase compensation unit that performs phase compensation, and a control unit that controls the electric motor based on the signal subjected to the phase compensation, wherein the phase compensation unit includes the phase compensation unit, Two different phase compensation controls corresponding to the vehicle state when an external force is applied to the vehicle and the vehicle state when no external force is applied are selected according to the vehicle state.

  According to the above configuration, the phase compensation unit selects two mutually different phase compensation controls corresponding to the vehicle state between the vehicle state when the external force is applied to the vehicle and the vehicle state when the external force is not applied. Do it.

  The phase compensation unit includes a phase lag compensation unit and a phase advance compensation unit, and each of the phase lag compensation unit and the phase advance compensation unit includes a vehicle state when an external force is applied to the vehicle, and an external force. It is preferable that two different phase compensation controls corresponding to the vehicle state in the case where the vehicle does not act are selected according to the steering state based on the steering torque and the vehicle state.

  According to the above configuration, the phase delay compensation unit and the phase advance compensation unit are different from each other corresponding to the vehicle state in the vehicle state when the external force is applied to the vehicle and the vehicle state when the external force is not applied. By selecting two phase compensation controls, phase compensation suitable for the vehicle state is performed.

In addition, it is preferable to include an external force presence / absence determining unit that determines the presence / absence of the action of an external force according to at least the lateral G information among the steering speed, yaw rate, and lateral G.
According to the above configuration, the external force presence / absence determining unit determines the presence or absence of the action of the external force according to at least the steering speed and the lateral G information among the steering speed, the yaw rate, and the lateral G.

  According to the present invention, phase compensation suitable for the vehicle state can be performed, and a steering feeling suitable for the vehicle state can be realized.

The lineblock diagram showing the composition of the electric power steering device of one embodiment. The block diagram which shows schematic structure of the control block in the electric power steering apparatus of one Embodiment. The block diagram which shows schematic structure of the phase compensation control part of one Embodiment. The block diagram which shows schematic structure of the phase delay compensation control part about an electric power steering apparatus. Explanatory drawing which shows the aspect of the phase delay compensation control based on an assist gradient. Explanatory drawing which shows the relationship between basic assist control amount and assist gradient. The block diagram which shows schematic structure of the phase advance compensation control part about an electric power steering apparatus. The flowchart which shows the calculation procedure of the assist gradient gain of the assist gradient gain calculation part when the turning follow-up steering determination flag is input. Explanatory drawing which shows the relationship between an assist gradient and an assist gradient gain. The flowchart which shows the calculation procedure of the system stabilization control amount of a system stabilization control part when a turning follow-up steering determination flag is input. The flowchart which shows the procedure which determines ON / OFF of the turning follow-up steering determination flag.

Hereinafter, an embodiment embodying an electric power steering device (hereinafter referred to as EPS) provided in a vehicle will be described with reference to FIGS.
As shown in FIG. 1, the EPS 1 controls the steering mechanism 2 that steers the steered wheels 15 based on the operation of the driver's steering wheel 10, the assist mechanism 3 that assists the driver's steering operation, and the assist mechanism 3. An ECU (electronic control unit) 30 is provided.

  The steering mechanism 2 includes a steering wheel 10 and a steering shaft 11 that rotates integrally with the steering wheel 10. The steering shaft 11 includes a column shaft 11a connected to the steering wheel 10, an intermediate shaft 11b connected to the lower end portion of the column shaft 11a, and a pinion shaft 11c connected to the lower end portion of the intermediate shaft 11b. Yes.

  A lower end portion of the pinion shaft 11 c is connected to the rack shaft 12 via a rack and pinion mechanism 13. Therefore, in the steering mechanism 2, the rotational movement of the steering shaft 11 is caused by the axis of the rack shaft 12 via the rack and pinion mechanism 13 including a pinion gear provided at the tip of the pinion shaft 11 c and a rack formed on the rack shaft 12. It is converted into a reciprocating linear motion in the direction (left-right direction in FIG. 1). The reciprocating linear motion is transmitted to the left and right steered wheels 15 via tie rods 14 respectively connected to both ends of the rack shaft 12, thereby changing the steered angle of the steered wheels 15. Here, the steering system is a system from the steering wheel 10 steered by the driver to the steered wheels 15.

  The assist mechanism 3 includes a motor 20 as an electric motor that is a source of assist force. A rotation shaft 21 of the motor 20 is connected to the column shaft 11a via a speed reduction mechanism 22. The reduction mechanism 22 reduces the rotation of the motor 20 and transmits the reduced rotational force to the column shaft 11a. That is, the turning force (torque) of the motor 20 is applied to the steering shaft 11 as an assist force, thereby assisting the driver's steering operation. As the motor 20, for example, a three-phase brushless motor that rotates based on three-phase (U, V, W) driving power is employed, but the motor 20 is not limited thereto.

  The ECU 30 controls the motor 20 based on the detection results of various sensors provided in the vehicle. Examples of various sensors include a torque sensor 40 and a rotation angle sensor 41. The torque sensor 40 is provided on the column shaft 11 a and the rotation angle sensor 41 is provided on the motor 20. The torque sensor 40 detects a steering torque Th0 applied to the steering shaft 11 in accordance with the driver's steering operation. The torque sensor 40 corresponds to a steering torque detector. The rotation angle sensor 41 detects the rotation angle θm of the rotation shaft 21.

  Further, as shown in FIG. 1, the lateral G sensor 18 and the yaw rate sensor 19 are connected to the ECU 30. The ECU 30 detects the lateral G (lateral acceleration) and the yaw rate δ based on the output signals of the lateral G sensor 18 and the yaw rate sensor 19.

  In this embodiment, the ECU 30 sets a target assist force based on the output of the torque sensor 40, and controls the current supplied to the motor 20 so that the actual assist force becomes the target assist force.

Next, the configuration of the ECU will be described in detail.
As shown in FIG. 2, the ECU 30 includes a microcomputer 31 that outputs a motor control signal to the drive circuit 32 and a drive circuit 32 that supplies drive power to the motor 20 based on the motor control signal. Yes. The microcomputer 31 corresponds to a control unit.

The microcomputer 31 includes an assist command value calculation unit 33, a current command value calculation unit 34, a motor control signal generation unit 36, and a turn additional steering determination unit 38 as an external force presence / absence determination unit.
The assist command value calculator 33 is based on the steering torque Th0 obtained from the torque sensor 40, and the basic assist control amount Tas * and the system stabilization control amount Tdt * 1 corresponding to the assist torque to be applied to the motor 20, or the system stability The control amount Tdt * 2 is calculated.

  The current command value calculation unit 34 calculates a current command value Ia * based on the basic assist control amount Tas * and the system stabilization control amount Tdt *. The motor control signal generation unit 36 sets the actual current value I detected by the current sensor 37 provided in the power supply path between the drive circuit 32 and the assist mechanism 3 and the rotation angle θm detected by the rotation angle sensor 41. Based on this, a motor control signal is generated so that the actual current value I follows the current command value I *.

Next, the assist command value calculation unit 33 will be specifically described.
The assist command value calculation unit 33 includes a torque shift control unit 50, a phase delay compensation control unit 51, a basic assist control unit 52, and a phase advance compensation control unit 53. The phase lag compensation control unit 51 corresponds to a phase lag compensation unit, and the phase lead compensation control unit 53 corresponds to a phase lead compensation unit. The phase lag compensation control unit 51 and the phase advance compensation control unit 53 correspond to a phase compensation unit.

  The torque shift control unit 50 calculates the correction torque Th by correcting the steering torque Th0 detected by the torque sensor 40 based on the steering state of the steering wheel 10 in order to improve the steering feeling. Specifically, the torque shift control unit 50 corrects the steering torque Th0 to increase when the steering wheel 10 is in the steering holding state or the switchback state, and corrects the steering torque Th0 when the steering wheel 10 is in the cutting state. Is set to “0”, the correction torque Th is calculated. The phase delay compensation control unit 51 delays the phase of the correction torque Th output from the torque shift control unit 50.

  The basic assist control unit 52 calculates the basic assist control amount Tas * as a basic component of the assist command value corresponding to the current command value Ia * based on the steering torque Th ′ after the phase delay compensation by the phase delay compensation control unit 51. To do.

  On the other hand, the phase advance compensation control unit 53 calculates the system stabilization control amount Tdt * by advancing the phase as a compensation component based on the differential value of the correction torque Th (correction torque differential value dTh).

  As shown in FIG. 4, the phase delay compensation control unit 51 includes an assist gradient gain calculation unit 51a that calculates an assist gradient gain Kag1 or Kag2 based on a turn follow-up steering determination flag and an assist gradient Rag, which will be described later, and an assist gradient Rag. Assist gradient sensitive filter 51b that changes the characteristics of phase lag compensation (filter coefficient, etc.) based on

  The assist gradient gain calculation unit 51a calculates smaller assist gradient gains Kag1 and Kag2 as the absolute value of the assist gradient Rag fetched from the basic assist control unit 52 is larger.

  When the assist gradient Rag has the same value, the assist gradient gain Kag1 is calculated when the turn additional steering determination flag is on (high G turn), and when the turn additional steering determination flag is off (non-high G turn). The assist gradient gain Kag2 (> Kag1) is calculated (see FIG. 9). The assist gradient gains Kag1 and Kag2 are values set in the range of 0 to 1.0.

  Further, as shown in FIG. 5, the assist gradient sensitive filter 51b selects a filter having a different gain G1 for each frequency f selected according to the assist gradient Rag (assist gradient gains Kag1, Kag2), and performs phase delay compensation. Do. The gain G1 is the ratio between the input and output of the assist gradient sensitive filter 51b, that is, the ratio between the correction torque Th before phase lag compensation and the correction torque Th 'after phase lag compensation. The phase delay compensation control unit 51 delays the phase of the correction torque Th ′ (first compensation value) after the phase delay compensation in accordance with the increase in the assist gradient Rag (in accordance with the decrease in the assist gradient gains Kag1 and Kag2). As described above (in order to reduce the gain), the phase delay compensation characteristics (such as gain G1) are changed.

  As shown in the graph of FIG. 6, the basic assist control unit 52 calculates a basic assist control amount Tas * having a larger absolute value as the absolute value of the steering torque Th ′ after phase delay compensation is larger. The absolute value of the assist gradient Rag is designed to increase as the absolute value of the correction torque Th ′ after phase delay compensation increases. The assist gradient Rag is a ratio of a change in the basic assist control amount Tas * with respect to a change in the steering torque Th ′ after the phase delay compensation. For example, the assist gradient Rag is the gradient of the tangent L shown in FIG.

As shown in FIG. 7, the phase lead compensation control unit 53 includes a torque differential value calculation unit 53a, a low-pass filter 53b, and a system stabilization control unit 53c.
The torque differential value calculation unit 53a calculates a corrected torque differential value dTh based on the input correction torque Th. The low-pass filter 53b performs low-pass filter processing on the input corrected torque differential value dTh and outputs the corrected torque differential value dTh ′ after the filter as the corrected torque after phase advance compensation.

  The system stabilization control unit 53c calculates the system stabilization control amount Tdt1 * or the system stabilization control amount Tdt2 * based on the corrected torque differential value dTh ′ after the filter, the assist gradient Rag, and the turn following steering determination flag. .

  That is, the system stabilization control unit 53c outputs the system stabilization control amount Tdt2 * when the turning follow-up steering determination flag is on, and the system stabilization control amount Tdt1 when the turning follow-up steering determination flag is off. * (<Tdt2 *) is output.

  Further, the system stabilization control unit 53c calculates the system stabilization control amount Tdt1 * and the system stabilization control amount Tdt2 * having larger absolute values as the absolute value of the corrected torque differential value dTh ′ is larger.

  The turn follow-up steering determination unit 38 shown in FIG. 2 grasps the vehicle state whether the vehicle is turning high G or non-high G based on the detected lateral G and yaw rate δ, and based on the steering speed, The steering state is ascertained, and it is determined whether or not the vehicle is following turning according to both states, and a turning follow-up steering determination flag that is the determination result is output to the phase delay compensation control unit 51 and the phase advance compensation control unit 53.

  Although not shown, the motor 20 is provided with a rotation angle sensor that detects the motor rotation angle. The ECU 30 includes a steering angle calculation unit (not shown) that calculates the actual steering angle of the steering wheel 10 based on the motor rotation angle detected by the rotation angle sensor, and a steering speed calculation unit that calculates the steering speed ( (Not shown) is provided. The steering angle calculation unit calculates a steering angle using a correlation between the motor rotation angle and the rotation angle of the steering shaft 11. In the present embodiment, when the steering wheel 10 is in the neutral position, the steering angle is “0 °”. The steering angle is defined to increase when the steering wheel 10 is operated in the right steering direction and to decrease when the steering wheel 10 is operated in the left steering direction. The steering speed calculation unit calculates a steering speed by performing a differential calculation on the steering angle.

(Operation of the embodiment)
Next, the operation of the assist gradient gain calculation unit 51a will be described.
As shown in FIG. 8, the assist gradient gain calculation unit 51a determines whether or not the input turn additional steering determination flag is on (S11). If the turn additional steering determination flag is off, the assist gradient gain Kag1 is output (S12), and the process is terminated. The assist gradient gain Kag1 is a value that changes according to the absolute value of the input assist gradient Rag. On the other hand, when the turn additional steering determination flag is ON, the assist gradient gain calculation unit 51a outputs the assist gradient gain Kag2 (S13), and the process ends.

  Incidentally, there is a relationship as shown in the graph of FIG. 9 between the assist gradient gains Kag1 and Kag2 and the assist gradient Rag. That is, the assist gradient gains Kag1 and Kag2 are values set in the range of 0 to 1.0 so as to be inversely proportional to the assist gradient Rag. Further, when the assist gradient gains Kag1 and Kag2 are “1”, the assist gradient Rag is “0”. As shown in FIG. 5, as the assist gradient Rag approaches “0” (assist gradient gain Kag1, Kag2 approaches “1”), the assist gradient sensitive filter 51b has a gain G1 regardless of the frequency f. The phase lag compensation is performed using a filter in which is almost “1”.

As shown in FIG. 9, when the assist gradient Rag is not “0”, the assist gradient gain Kag2> Kag1 when the assist gradient Rag has the same value.
As a result, when the turn additional steering determination flag is on, the assist gradient gain Kag2 is set, so that the phase of the correction torque Th ′ after phase delay compensation is suppressed, and the followability of the correction torque Th ′ is improved. It is done.

  On the other hand, when the turn additional steering determination flag is off, the assist gradient gain Kag1 is used, so that the phase of the correction torque Th ′ after phase delay compensation is promoted, and the followability of the correction torque Th ′ is suppressed. Is done.

Next, the operation of the phase lead compensation controller 53 will be described.
The torque differential value calculation unit 53a shown in FIG. 7 calculates the corrected torque differential value dTh after filtering based on the input correction torque Th, and outputs it to the low-pass filter 53b. The low-pass filter 53b performs low-pass filter processing on the input corrected torque differential value dTh and outputs the corrected torque differential value dTh ′ after the filter to the system stabilization control unit 53c as a corrected torque after phase advance compensation.

The system stabilization control unit 53c performs processing as follows.
As shown in FIG. 10, the system stabilization control unit 53c determines whether or not the input turn additional steering determination flag is on (S21). When the turn additional steering determination flag is off, the system stabilization control unit 53c calculates the system stabilization control amount Tdt1 * (<Tdt2 *) based on the corrected torque differential value dTh ′ and the assist gradient Rag after filtering. It calculates and outputs to the electric current command value calculating part 34 (S22), and complete | finishes a process. On the other hand, the system stabilization control unit 53c determines the system stabilization control amount Tdt2 * based on the corrected torque differential value dTh ′ and the assist gradient Rag after the filter when the turn additional steering determination flag is on. It calculates and outputs to the electric current command value calculating part 34 (S23), and complete | finishes a process.

  As described above, when the turning follow-up steering determination flag is ON, the system stabilization control amount Tdt2 * (> system stabilization control amount Tdt1 *) is supplied from the system stabilization control unit 53c to the current command value calculation unit 34. Therefore, in the current command value calculation unit 34, the system stabilization control amount Tdt2 * that increases the phase advance compensation is added to the basic assist control amount Tas *.

  When the turn additional steering determination flag is off, the system stabilization control unit 53c outputs the system stabilization control amount Tdt1 * (<system stabilization control amount Tdt2 *) to the current command value calculation unit 34. In the current command value calculation unit 34, the system stabilization control amount Tdt2 * that reduces the phase advance compensation is added to the basic assist control amount Tas *.

Next, an on / off determination method for the turn additional steering determination flag will be described. FIG. 11 is a flowchart of a program executed by the ECU 30 every predetermined control cycle.
As shown in FIG. 11, the turn follow-up steering determination unit 38 determines whether or not a turn follow-up steering determination condition is satisfied with respect to the vehicle state and the steering state (S31).

  The additional turning steering determination condition is that the lateral G is equal to or greater than the lateral G determination threshold Ga, the yaw rate δ is equal to or greater than the yaw rate determination threshold δa, and the steering speed is equal to or greater than the steering speed determination threshold. When the lateral G is equal to or greater than the lateral G determination threshold Ga and the yaw rate δ is equal to or greater than the yaw rate determination threshold δa, the vehicle state is a high G turning state, and when the steering speed is equal to or higher than the steering speed determination threshold, This means that follow-up steering is being performed and external force is acting on the vehicle.

  Moreover, when the above-mentioned turning additional steering determination condition is not satisfied, it means a state in which no additional force is applied without additional steering. The lateral G determination threshold Ga, the yaw rate determination threshold δa, and the steering speed determination threshold are values obtained by a test or the like, and are stored in a memory (not shown).

  In S31, when the turn additional steering determination condition is not satisfied (NO in S31), the process proceeds to S32, the turn additional steering determination flag is set to OFF, and this flowchart is temporarily ended.

  In S31, when the turn additional steering determination condition is satisfied (YES in S31), the process proceeds to S33. In S33, it is determined whether or not the turning follow-up steering determination flag of the previous value (the value before one cycle) is on. Note that the turning follow-up steering determination flag in the initial state is normally set to off. When the turn follow-up steering determination flag of the previous value is off (NO in S33), the turn follow-up steering determination flag is set on (S34), and this flowchart is temporarily ended.

  In S33, if the turn follow-up steering determination flag of the previous value (the value before one cycle) is on, the process proceeds to S35, the turn follow-up steering determination flag is kept on, and this flowchart is temporarily ended. .

  By performing the phase compensation as described above, when the vehicle is turning at a high G and the steering speed is steered faster than the steering speed determination threshold value, the phase lag compensation control unit 51 reduces the phase lag compensation, The advance compensation control unit 53 increases the phase advance compensation. As a result, when the vehicle is turning at a high G and the steering speed is higher than the steering speed determination threshold, the assist followability of the motor 20 can be improved, so that insufficient assist does not occur.

  Further, when the vehicle is in a normal state, that is, during a high G turn and the steering speed is less than the steering speed determination threshold, or when the vehicle is a non-high G turn, the phase delay compensation control unit 51 The delay compensation is increased, and the phase advance compensation controller 53 reduces the phase advance compensation. In this case, since the gain in the phase lead compensation does not increase in the normal time of the vehicle, the noise of the detection signal of the torque sensor does not deteriorate, and the road information does not deteriorate.

This embodiment has the following features.
(1) In the EPS 1 (electric power steering apparatus) of the present embodiment, the phase lag compensation control unit 51 and the phase advance compensation control unit 53 (phase compensation unit) have a vehicle state when an external force acts on the vehicle, and an external force Two mutually different phase compensation controls corresponding to the vehicle state when not acting are selected according to the vehicle state. As a result, according to this embodiment, phase compensation suitable for the vehicle state can be performed, and a steering feeling suitable for the vehicle state can be realized.

  (2) In the EPS 1 of the present embodiment, each of the phase delay compensation control unit 51 and the phase advance compensation control unit 53 corresponds to a vehicle state when an external force is applied to the vehicle and a vehicle state when no external force is applied. Two different phase compensation controls are selected according to the steering state based on the steering torque and the vehicle state. As a result, according to the present embodiment, the phase delay compensation control unit 51 (phase delay compensation unit) and the phase advance compensation control unit 53 (phase advance compensation unit) can perform phase compensation that matches the vehicle state. The steering feeling suitable for the vehicle state can be realized.

  (3) In the EPS 1 (electric power steering apparatus) of the present embodiment, the turn follow-up steering determination unit 38 (external force presence / absence determination) that determines the presence / absence of an external force acting on the vehicle according to the steering speed, yaw rate, and lateral G information. Part). As a result, according to the present embodiment, the external force presence / absence determining unit can easily determine the presence / absence of the action of the external force based on the steering speed, the yaw rate, and the lateral G.

In addition, embodiment of this invention is not limited to the said embodiment, You may change as follows.
In the embodiment, the target assist force is set based on the steering torque, but the target assist force may be set based on the steering torque 0 and the vehicle speed.

In the embodiment, a brushless motor is used as the motor 20, but a motor with a brush may be used.
In the above-described embodiment, a column-type electric power steering device is specifically illustrated. However, the present invention is not limited to this. For example, a rack parallel type electric power steering apparatus may be used.

  In the embodiment, the presence / absence determination of the external force is determined based on the steering speed, the lateral G (lateral acceleration), and the yaw rate. However, the determination may be performed based on the steering speed and the lateral G, or the yaw rate and the lateral G ( Lateral acceleration) or only lateral G (lateral acceleration) information may be used. Note that, when the presence / absence determination of the external force is performed by the determination of the steering speed, the lateral G, and the yaw rate as in the above-described embodiment, the determination accuracy can be improved more than the determination of the steering speed and the lateral G.

  In the embodiment, the phase delay compensation control unit 51 and the phase advance compensation control unit 53 are provided in order to perform compensation control on the basic assist control amount Tas *. However, only one of them is provided. Also good.

  In the present embodiment, the correction torque Th output from the torque shift control unit 50 is input to the phase lag compensation control unit 51 and the phase advance compensation control unit 53, but is not limited thereto. For example, the steering torque Th0 may be input to the phase advance compensation control unit 53, and the system stabilization control amount Tdt * may be calculated based on the steering torque Th0. Further, the phase shift compensation and the phase advance compensation may be performed using the steering torque Th0 without providing the torque shift control unit 50.

  In the embodiment, the phase advance compensation control unit 53 includes the torque differential value calculation unit 53a and performs the phase advance compensation using the corrected torque differential value. However, the present invention is not limited to this. For example, phase advance compensation may be performed using the difference value of the correction torque.

  In the above embodiment, the low-pass filter 53b is provided in the phase advance compensation control unit 53, but this is not a limitation. For example, a high-pass filter for removing a low frequency component of the corrected torque differential value dTh may be provided as necessary.

  In the embodiment, the rotation angle sensor 41 detects the rotation angle θm from the rotation shaft 21 of the motor 20, but is not limited thereto. For example, the pinion angle may be detected.

1 ... EPS (electric power steering device), 2 ... steering mechanism,
3. Assist mechanism, 10 ... Steering wheel,
11 ... Steering shaft, 11a ... Column shaft,
11b: Intermediate shaft, 11c: Intermediate shaft,
12 ... rack shaft, 13 ... rack and pinion mechanism, 14 ... tie rod,
15 ... steered wheel, 18 ... lateral G sensor, 19 ... yaw rate sensor,
20 ... motor (electric motor), 21 ... rotary shaft, 22 ... deceleration mechanism,
30 ... ECU (electronic control unit), 31 ... microcomputer (control unit),
32 ... Drive circuit, 33 ... Assist command value calculation unit, 34 ... Current command value calculation unit,
36: Motor control signal generator, 37: Current sensor,
38 ... turning additional steering determination unit (external force presence / absence determination unit),
40 ... torque sensor (steering torque detector), 41 ... rotation angle sensor,
50 ... torque shift control unit,
51 ... Phase lag compensation control unit (phase lag compensation unit, phase compensation unit),
51a ... assist gradient gain calculation unit, 51b ... assist gradient sensitive filter,
52 ... Basic assist control unit,
53 ... Phase advance compensation control unit (phase advance compensation unit, phase compensation unit),
53a ... Torque differential value calculation unit, 53b ... Low pass filter,
53c: System stabilization control unit, Th0: Steering torque, Th: Correction torque,
Th ′: Correction torque after compensation for phase delay (first compensation value), Rag: Assist gradient,
Kag: assist gradient gain, G1: gain, dTh: corrected torque differential value,
dTh ′: corrected torque differential value after filtering (second compensation value),
Tas *: Basic assist control amount (basic control amount), Tdt *: System stabilization control amount,
I *: current command value, Ilim: current limit value, Ia *: current command value,
I: actual current value (current value), θm: rotation angle, δ: yaw rate.

Claims (3)

A steering torque detector that detects a steering torque acting on a steering system of the vehicle; an electric motor that applies an auxiliary torque to the steering system; and a phase compensation unit that performs phase compensation on the steering torque. An electric power steering apparatus comprising: a control unit that controls the electric motor based on a performed signal,
The phase compensation unit performs two different phase compensation controls corresponding to the vehicle state when an external force is applied to the vehicle and the vehicle state when no external force is applied, according to the vehicle state. Electric power steering device. The phase compensation unit includes a phase lag compensation unit and a phase advance compensation unit,
Each of the phase delay compensation unit and the phase advance compensation unit performs two different phase compensation controls corresponding to a vehicle state when an external force acts on the vehicle and a vehicle state when no external force acts on the vehicle, The electric power steering apparatus according to claim 1, wherein the electric power steering apparatus is selected according to a steering state based on a steering torque and the vehicle state.   3. The electric power steering apparatus according to claim 1, further comprising an external force presence / absence determination unit that determines whether or not the external force is applied according to at least information on the lateral G among a steering speed, a yaw rate, and a lateral G. 4.

Images