WO2016204072A1 - Electric power steering device - Google Patents

Electric power steering device Download PDF

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Publication number
WO2016204072A1
WO2016204072A1 PCT/JP2016/067269 JP2016067269W WO2016204072A1 WO 2016204072 A1 WO2016204072 A1 WO 2016204072A1 JP 2016067269 W JP2016067269 W JP 2016067269W WO 2016204072 A1 WO2016204072 A1 WO 2016204072A1
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WIPO (PCT)
Prior art keywords
steering
turning angle
angle
torque sensor
acquisition unit
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PCT/JP2016/067269
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French (fr)
Japanese (ja)
Inventor
修 宮谷
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KYB Corp
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KYB Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits

Definitions

  • the present invention relates to an electric power steering apparatus.
  • JPH11-59447A controls the driving of the motor based on the vehicle speed signal and the steering torque signal from the steering torque sensor when the steering torque sensor is normal.
  • a device that controls the driving of an electric motor using a steering torque estimated based on a vehicle speed signal and a steering angle signal.
  • An object of the present invention is to improve the steering feeling when a torque sensor fails.
  • an electric power steering device wherein an electric motor that applies a steering assist torque that assists a steering operation by a driver based on a detection result of the torque sensor when the torque sensor is normal, and a torque A failure determination unit that determines a sensor failure, a steering angle acquisition unit that acquires a steering angle associated with a steering operation, a turning angle acquisition unit that acquires a steering angle of a wheel, and a failure determination unit that detects a failure of a torque sensor. If it is determined, the target turning angle of the wheel is set based on the acquisition result of the steering angle acquisition unit, and electric power is applied so that the turning angle acquired by the turning angle acquisition unit matches the target turning angle. And a motor control unit that controls driving of the motor.
  • FIG. 1 is a configuration diagram of an electric power steering apparatus according to an embodiment of the present invention.
  • FIG. 2 is a control block diagram of the electric power steering apparatus according to the embodiment of the present invention.
  • an electric power steering apparatus 100 includes an input shaft 2 that rotates in response to an operation of a steering wheel 1 by a driver (hereinafter referred to as “steering operation”), and a rack that steers wheels 6.
  • An output shaft 3 linked to the shaft 5 and a torsion bar 4 connecting the input shaft 2 and the output shaft 3 are provided.
  • a steering shaft 7 is configured by the input shaft 2, the output shaft 3, and the torsion bar 4.
  • a pinion gear 3a that meshes with a rack gear 5a formed on the rack shaft 5 is formed below the output shaft 3.
  • the electric power steering apparatus 100 includes an electric motor 10 that is a power source for assisting the driver in steering the steering wheel 1, and a speed reducer 11 that decelerates and transmits the rotation of the electric motor 10 to the steering shaft 7. , A torque sensor 12 for detecting the torque acting on the torsion bar 4 by the relative rotation of the input shaft 2 and the output shaft 3 accompanying the steering operation by the driver, and driving of the electric motor 10 based on the detection result of the torque sensor 12 And a controller 30 for controlling.
  • an electric motor 10 that is a power source for assisting the driver in steering the steering wheel 1
  • a speed reducer 11 that decelerates and transmits the rotation of the electric motor 10 to the steering shaft 7.
  • a torque sensor 12 for detecting the torque acting on the torsion bar 4 by the relative rotation of the input shaft 2 and the output shaft 3 accompanying the steering operation by the driver, and driving of the electric motor 10 based on the detection result of the torque sensor 12
  • a controller 30 for controlling.
  • the electric motor 10 is provided with a motor rotation angle sensor 10a as a motor rotation angle detector that detects the rotation angle of the electric motor 10.
  • the motor rotation angle sensor 10a is configured by a resolver.
  • the reducer 11 includes a worm shaft 11a connected to the output shaft of the electric motor 10 and a worm wheel 11b connected to the output shaft 3 and meshing with the worm shaft 11a.
  • the torque output from the electric motor 10 is transmitted from the worm shaft 11a to the worm wheel 11b and applied to the output shaft 3 as a steering assist torque.
  • the torque output from the electric motor 10 may be applied to the rack shaft 5 through the speed reducer.
  • the electric motor 10 applies steering assist torque to the steering system.
  • the steering torque applied to the input shaft 2 in accordance with the steering operation by the driver is detected by the torque sensor 12, and the torque sensor 12 outputs a voltage signal corresponding to the steering torque to the controller 30.
  • the controller 30 calculates the torque output from the electric motor 10 based on the voltage signal from the torque sensor 12, and controls the driving of the electric motor 10 so that the torque is generated.
  • the electric power steering apparatus 100 detects the steering torque applied to the input shaft 2 with the torque sensor 12, and controls the drive of the electric motor 10 with the controller 30 based on the detection result. Assist steering operation.
  • the torque sensor 12 is connected to the controller 30 through two systems, a main system and a sub system.
  • the input shaft 2 is provided with a steering angle sensor 15 as a steering angle acquisition unit that acquires a steering angle (absolute steering angle) that is a rotation angle of the steering wheel 1. Since the rotation angle of the input shaft 2 is equal to the steering angle of the steering wheel 1, the steering angle of the steering wheel 1 can be obtained by detecting the rotation angle of the input shaft 2 by the steering angle sensor 15. The detection result of the steering angle sensor 15 is output to the controller 30.
  • the steering angle sensor 15 includes a center gear that rotates integrally with the input shaft 2 and two outer gears that mesh with the center gear. Based on the change in magnetic flux accompanying the rotation of the two outer gears, The rotation angle of the center gear, that is, the rotation angle of the input shaft 2 is calculated.
  • the controller 30 is detected by a CPU that controls the operation of the electric motor 10, a ROM that stores control programs and setting values necessary for the processing operation of the CPU, and various sensors such as the torque sensor 12 and the steering angle sensor 15. And a RAM for temporarily storing information.
  • FIG. 2 is a control block diagram of the electric power steering apparatus.
  • the controller 30 includes a motor control unit 31 that controls driving of the electric motor 10, a failure determination unit 32 that determines failure of the torque sensor 12, and a turning angle acquisition unit 33 that acquires the actual turning angle of the wheel 6. .
  • the motor control unit 31 controls the drive of the electric motor 10 based on the detection result of the torque sensor 12 when the torque sensor 12 is normal, and acquires the detection result and the turning angle of the steering angle sensor 15 when the torque sensor 12 fails.
  • the drive of the electric motor 10 is controlled based on the turning angle of the wheel 6 acquired by the unit 33.
  • a voltage signal output from the main system is used to control the electric motor 10.
  • the voltage signal output from the sub system is not used for controlling the electric motor 10 but is used for determining a failure of the torque sensor 12.
  • the failure determination unit 32 compares the output voltage output from the main system and the output voltage output from the sub system, and determines that the difference is greater than or equal to a predetermined tolerance, the torque sensor 12 Is determined to be malfunctioning.
  • the motor control unit 31 controls the drive of the electric motor 10 based on the detection result of the torque sensor 12.
  • the motor control unit 31 switches the control method of the electric motor 10 from assist control based on the detection result of the torque sensor 12 to turning angle control based on the detection result of the steering angle sensor 15. Below, turning angle control at the time of failure of the torque sensor 12 is demonstrated.
  • the motor control unit 31 sets the target turning angle of the wheel 6 based on the detection result of the steering angle sensor 15.
  • the turning angle acquisition unit 33 calculates the actual turning angle of the wheel 6 based on the detection result of the motor rotation angle sensor 10a. Specifically, the turning angle acquisition unit 33 calculates the rotation angle of the output shaft 3 based on the detection result of the motor rotation angle sensor 10a and the reduction ratio of the speed reducer 11, and the rotation angle of the output shaft 3 and the pinion gear 3a. And the amount of movement of the rack shaft 5 in the axial direction is calculated from the reduction ratio of the rack gear 5a, and the actual turning angle of the wheel 6 is calculated based on the amount of movement. And the motor control part 31 controls the drive of the electric motor 10 so that the actual turning angle of the wheel 6 acquired by the turning angle acquisition part 33 may correspond with a target turning angle.
  • the assist control based on the detection result of the torque sensor 12 is switched to the turning angle control based on the steering angle of the steering wheel 1 accompanying the steering operation.
  • the torsion bar 4 is twisted, so that the steering of the steering wheel 1 is not so heavy and the steering wheel 1 is several times. Rotate. If the steering wheel 1 rotates several degrees, the rotation angle is detected by the steering angle sensor 15, so the target turning angle is set by the motor control unit 31 and the electric motor 10 is controlled. Therefore, even in the electric power steering apparatus 100 in which the steering wheel 1 and the rack shaft 5 are mechanically connected, the turning angle control is possible.
  • the actual turning angle of the wheel 6 acquired by the turning angle acquisition unit 33 matches the target turning angle set based on the detection result of the steering angle sensor 15.
  • the drive of the electric motor 10 is controlled.
  • the target turning angle is set in accordance with the steering operation of the driver, and the drive of the electric motor 10 is controlled so that the actual turning angle of the wheel 6 matches the target turning angle. Further, it is possible to improve the steering feeling when the torque sensor 12 fails.
  • the electric power steering apparatus 100 includes an input shaft 2 that rotates in accordance with a steering operation by a driver, an output shaft 3 that is linked to a rack shaft 5 that steers wheels 6, an input shaft 2, and an output shaft. 3, a torque sensor 12 that detects torque acting on the torsion bar 4, and a steering assist that assists the driver in steering operation based on the detection result of the torque sensor 12 when the torque sensor 12 is normal.
  • the electric motor 10 that applies torque
  • the failure determination unit 32 that determines failure of the torque sensor 12
  • the steering angle sensor 15 that acquires the steering angle associated with the steering operation
  • the turning angle that acquires the turning angle of the wheel 6
  • a motor control unit that sets the target turning angle of the wheel 6 based on the result and controls the drive of the electric motor 10 so that the turning angle acquired by the turning angle acquisition unit 33 matches the target turning angle. 31.
  • the electric motor is set such that the turning angle acquired by the turning angle acquisition unit 33 matches the target turning angle set based on the acquisition result of the steering angle sensor 15. 10 drive is controlled.
  • the turning angle control is performed based on the steering angle associated with the steering operation, not the assist control. Therefore, it is possible to improve the steering feeling when the torque sensor fails.
  • a pinion shaft that meshes with the rack gear 5a may be provided separately from the output shaft 3, and the output shaft 3 and the pinion shaft may be connected via a universal joint.
  • the mode in which the target turning angle of the wheel 6 is set based on the detection result of the steering angle sensor 15 has been described. Instead of this, if the vehicle speed information and the like are taken into account in addition to the detection result of the steering angle sensor 15, a more accurate target turning angle can be set.
  • the turning angle acquisition unit 33 has been described with respect to the form of calculating the actual turning angle of the wheel 6 based on the detection result of the motor rotation angle sensor 10a.
  • a turning angle sensor for detecting the actual turning angle of the wheel 6 may be provided, and the actual turning angle of the wheel 6 may be directly acquired instead of the calculation.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Steering Control In Accordance With Driving Conditions (AREA)
  • Power Steering Mechanism (AREA)

Abstract

The electric power steering device is provided with: an electric motor 10 for imparting a steering assist torque for assisting a steering operation by the driver on the basis of the detection result of a torque sensor 12 when the torque sensor 12 is operating normally; a failure determination unit 32 for determining a failure of the torque sensor 12; a steering angle acquisition unit 15 for acquiring the steering angle associated with the steering operation; a turning angle acquisition unit 33 for acquiring the turning angle of wheels 6; and a motor control unit 31 that, when the failure determination unit 32 has determined a failure of the torque sensor 12, sets a target steering angle of the wheels 6 on the basis of the acquisition result of the steering angle acquisition unit 15, and controls the driving of the electric motor 10 such that the turning angle acquired by the turning angle acquisition unit 33 matches the target steering angle.

Description

電動パワーステアリング装置Electric power steering device

　本発明は、電動パワーステアリング装置に関するものである。 The present invention relates to an electric power steering apparatus.

　従来の電動パワーステアリング装置として、ＪＰＨ１１－５９４４７Ａには、操舵トルクセンサが正常の場合には、車速信号と操舵トルクセンサからの操舵トルク信号とに基づいて電動機の駆動を制御し、操舵トルクセンサが故障と判断された場合には、車速信号と操舵角信号とに基づいて推定した操舵トルクを用いて電動機の駆動を制御するものが開示されている。 As a conventional electric power steering device, JPH11-59447A controls the driving of the motor based on the vehicle speed signal and the steering torque signal from the steering torque sensor when the steering torque sensor is normal. In the case where it is determined that there is a failure, there is disclosed a device that controls the driving of an electric motor using a steering torque estimated based on a vehicle speed signal and a steering angle signal.

　ＪＰＨ１１－５９４４７Ａに記載の電動パワーステアリング装置では、トルクセンサが故障した場合であっても、電動モータによるアシスト制御が継続される。その際には、車速信号と操舵角信号とに基づいて推定した操舵トルクを用いて電動機の駆動が制御されるため、操舵フィーリングは操舵トルクの推定精度に大きく依存することになる。しかし、車速信号と操舵角信号とに基づく操舵トルクの推定精度は高いものではないため、トルクセンサの故障時には良好な操舵フィーリングが得られないという問題がある。 In the electric power steering apparatus described in JPH11-59447A, assist control by the electric motor is continued even when the torque sensor fails. In that case, since the drive of the electric motor is controlled using the steering torque estimated based on the vehicle speed signal and the steering angle signal, the steering feeling greatly depends on the estimation accuracy of the steering torque. However, since the estimation accuracy of the steering torque based on the vehicle speed signal and the steering angle signal is not high, there is a problem that a good steering feeling cannot be obtained when the torque sensor fails.

　本発明は、トルクセンサ故障時の操舵フィーリングを向上させることを目的とする。 An object of the present invention is to improve the steering feeling when a torque sensor fails.

　本発明のある態様によれば、電動パワーステアリング装置であって、トルクセンサの正常時に、トルクセンサの検出結果に基づいて運転者によるステアリング操作を補助する操舵補助トルクを付与する電動モータと、トルクセンサの故障を判定する故障判定部と、ステアリング操作に伴う操舵角を取得する操舵角取得部と、車輪の転舵角を取得する転舵角取得部と、故障判定部がトルクセンサの故障を判定した場合には、操舵角取得部の取得結果に基づいて車輪の目標転舵角を設定し、転舵角取得部にて取得された転舵角が目標転舵角に一致するように電動モータの駆動を制御するモータ制御部と、を備えることを特徴とする。 According to an aspect of the present invention, there is provided an electric power steering device, wherein an electric motor that applies a steering assist torque that assists a steering operation by a driver based on a detection result of the torque sensor when the torque sensor is normal, and a torque A failure determination unit that determines a sensor failure, a steering angle acquisition unit that acquires a steering angle associated with a steering operation, a turning angle acquisition unit that acquires a steering angle of a wheel, and a failure determination unit that detects a failure of a torque sensor. If it is determined, the target turning angle of the wheel is set based on the acquisition result of the steering angle acquisition unit, and electric power is applied so that the turning angle acquired by the turning angle acquisition unit matches the target turning angle. And a motor control unit that controls driving of the motor.

図１は、本発明の実施形態に係る電動パワーステアリング装置の構成図である。FIG. 1 is a configuration diagram of an electric power steering apparatus according to an embodiment of the present invention. 図２は、本発明の実施形態に係る電動パワーステアリング装置の制御ブロック図である。FIG. 2 is a control block diagram of the electric power steering apparatus according to the embodiment of the present invention.

　以下、図面を参照して、本発明の実施形態に係る電動パワーステアリング装置１００について説明する。 Hereinafter, an electric power steering apparatus 100 according to an embodiment of the present invention will be described with reference to the drawings.

　図１に示すように、電動パワーステアリング装置１００は、運転者によるステアリングホイール１の操作（以下、「ステアリング操作」と称する。）に伴って回転する入力シャフト２と、車輪６を転舵するラック軸５に連係する出力シャフト３と、入力シャフト２と出力シャフト３を連結するトーションバー４と、を備える。入力シャフト２、出力シャフト３、及びトーションバー４によってステアリングシャフト７が構成される。 As shown in FIG. 1, an electric power steering apparatus 100 includes an input shaft 2 that rotates in response to an operation of a steering wheel 1 by a driver (hereinafter referred to as “steering operation”), and a rack that steers wheels 6. An output shaft 3 linked to the shaft 5 and a torsion bar 4 connecting the input shaft 2 and the output shaft 3 are provided. A steering shaft 7 is configured by the input shaft 2, the output shaft 3, and the torsion bar 4.

　出力シャフト３の下部には、ラック軸５に形成されたラックギヤ５ａと噛み合うピニオンギヤ３ａが形成される。ステアリングホイール１が操作されると、ステアリングシャフト７が回転し、その回転がピニオンギヤ３ａ及びラックギヤ５ａによってラック軸５の直線運動に変換され、ナックルアーム１４を介して車輪６が転舵される。 A pinion gear 3a that meshes with a rack gear 5a formed on the rack shaft 5 is formed below the output shaft 3. When the steering wheel 1 is operated, the steering shaft 7 rotates, and the rotation is converted into a linear motion of the rack shaft 5 by the pinion gear 3a and the rack gear 5a, and the wheel 6 is steered through the knuckle arm 14.

　また、電動パワーステアリング装置１００は、運転者によるステアリングホイール１の操舵を補助するための動力源である電動モータ１０と、電動モータ１０の回転をステアリングシャフト７に減速して伝達する減速機１１と、運転者によるステアリング操作に伴う入力シャフト２と出力シャフト３との相対回転によってトーションバー４に作用するトルクを検出するトルクセンサ１２と、トルクセンサ１２の検出結果に基づいて電動モータ１０の駆動を制御するコントローラ３０と、をさらに備える。 The electric power steering apparatus 100 includes an electric motor 10 that is a power source for assisting the driver in steering the steering wheel 1, and a speed reducer 11 that decelerates and transmits the rotation of the electric motor 10 to the steering shaft 7. , A torque sensor 12 for detecting the torque acting on the torsion bar 4 by the relative rotation of the input shaft 2 and the output shaft 3 accompanying the steering operation by the driver, and driving of the electric motor 10 based on the detection result of the torque sensor 12 And a controller 30 for controlling.

　電動モータ１０には、電動モータ１０の回転角度を検出するモータ回転角検出部としてのモータ回転角センサ１０ａが設けられる。モータ回転角センサ１０ａは、レゾルバによって構成される。 The electric motor 10 is provided with a motor rotation angle sensor 10a as a motor rotation angle detector that detects the rotation angle of the electric motor 10. The motor rotation angle sensor 10a is configured by a resolver.

　減速機１１は、電動モータ１０の出力軸に連結されるウォームシャフト１１ａと、出力シャフト３に連結されウォームシャフト１１ａに噛み合うウォームホイール１１ｂと、からなる。電動モータ１０が出力するトルクは、ウォームシャフト１１ａからウォームホイール１１ｂに伝達されて出力シャフト３に操舵補助トルクとして付与される。 The reducer 11 includes a worm shaft 11a connected to the output shaft of the electric motor 10 and a worm wheel 11b connected to the output shaft 3 and meshing with the worm shaft 11a. The torque output from the electric motor 10 is transmitted from the worm shaft 11a to the worm wheel 11b and applied to the output shaft 3 as a steering assist torque.

　電動モータ１０が出力するトルクを減速機１１を介して出力シャフト３に付与する構成に代えて、電動モータ１０が出力するトルクを減速機を介してラック軸５に付与する構成としてもよい。このように、電動モータ１０は、ステアリング系に操舵補助トルクを付与するものである。 Instead of the configuration in which the torque output from the electric motor 10 is applied to the output shaft 3 through the speed reducer 11, the torque output from the electric motor 10 may be applied to the rack shaft 5 through the speed reducer. As described above, the electric motor 10 applies steering assist torque to the steering system.

　運転者によるステアリング操作に伴って入力シャフト２に付与される操舵トルクはトルクセンサ１２によって検出され、トルクセンサ１２はその操舵トルクに対応する電圧信号をコントローラ３０に出力する。コントローラ３０は、トルクセンサ１２からの電圧信号に基づいて、電動モータ１０が出力するトルクを演算し、そのトルクが発生するように電動モータ１０の駆動を制御する。このように、電動パワーステアリング装置１００は、入力シャフト２に付与される操舵トルクをトルクセンサ１２にて検出し、その検出結果に基づいて電動モータ１０の駆動をコントローラ３０にて制御して運転者のステアリング操作をアシストする。 The steering torque applied to the input shaft 2 in accordance with the steering operation by the driver is detected by the torque sensor 12, and the torque sensor 12 outputs a voltage signal corresponding to the steering torque to the controller 30. The controller 30 calculates the torque output from the electric motor 10 based on the voltage signal from the torque sensor 12, and controls the driving of the electric motor 10 so that the torque is generated. As described above, the electric power steering apparatus 100 detects the steering torque applied to the input shaft 2 with the torque sensor 12, and controls the drive of the electric motor 10 with the controller 30 based on the detection result. Assist steering operation.

　トルクセンサ１２は、メイン系統とサブ系統の２つの系統にてコントローラ３０に接続される。 The torque sensor 12 is connected to the controller 30 through two systems, a main system and a sub system.

　入力シャフト２には、ステアリングホイール１の回転角度である操舵角（絶対操舵角）を取得する操舵角取得部としての操舵角センサ１５が設けられる。入力シャフト２の回転角度とステアリングホイール１の操舵角とは等しいため、操舵角センサ１５にて入力シャフト２の回転角度を検出することによってステアリングホイール１の操舵角が得られる。操舵角センサ１５の検出結果はコントローラ３０に出力される。 The input shaft 2 is provided with a steering angle sensor 15 as a steering angle acquisition unit that acquires a steering angle (absolute steering angle) that is a rotation angle of the steering wheel 1. Since the rotation angle of the input shaft 2 is equal to the steering angle of the steering wheel 1, the steering angle of the steering wheel 1 can be obtained by detecting the rotation angle of the input shaft 2 by the steering angle sensor 15. The detection result of the steering angle sensor 15 is output to the controller 30.

　操舵角センサ１５は、図示しないが、入力シャフト２と一体に回転するセンターギアと、センターギアに噛み合う２つのアウターギアと、を備え、２つのアウターギアの回転に伴う磁束の変化に基づいて、センターギアの回転角度、すなわち入力シャフト２の回転角度を演算するものである。 Although not shown, the steering angle sensor 15 includes a center gear that rotates integrally with the input shaft 2 and two outer gears that mesh with the center gear. Based on the change in magnetic flux accompanying the rotation of the two outer gears, The rotation angle of the center gear, that is, the rotation angle of the input shaft 2 is calculated.

　コントローラ３０は、電動モータ１０の動作を制御するＣＰＵと、ＣＰＵの処理動作に必要な制御プログラムや設定値等が記憶されたＲＯＭと、トルクセンサ１２や操舵角センサ１５等の各種センサが検出した情報を一時的に記憶するＲＡＭと、を備える。 The controller 30 is detected by a CPU that controls the operation of the electric motor 10, a ROM that stores control programs and setting values necessary for the processing operation of the CPU, and various sensors such as the torque sensor 12 and the steering angle sensor 15. And a RAM for temporarily storing information.

　次に、図２を参照して、コントローラ３０について説明する。図２は、電動パワーステアリング装置の制御ブロック図である。 Next, the controller 30 will be described with reference to FIG. FIG. 2 is a control block diagram of the electric power steering apparatus.

　コントローラ３０は、電動モータ１０の駆動を制御するモータ制御部３１と、トルクセンサ１２の故障を判定する故障判定部３２と、車輪６の実際の転舵角を取得する転舵角取得部３３と、を備える。 The controller 30 includes a motor control unit 31 that controls driving of the electric motor 10, a failure determination unit 32 that determines failure of the torque sensor 12, and a turning angle acquisition unit 33 that acquires the actual turning angle of the wheel 6. .

　モータ制御部３１は、トルクセンサ１２の正常時には、トルクセンサ１２の検出結果に基づいて電動モータ１０の駆動を制御し、トルクセンサ１２の故障時には、操舵角センサ１５の検出結果及び転舵角取得部３３によって取得された車輪６の転舵角に基づいて電動モータ１０の駆動を制御する。 The motor control unit 31 controls the drive of the electric motor 10 based on the detection result of the torque sensor 12 when the torque sensor 12 is normal, and acquires the detection result and the turning angle of the steering angle sensor 15 when the torque sensor 12 fails. The drive of the electric motor 10 is controlled based on the turning angle of the wheel 6 acquired by the unit 33.

　トルクセンサ１２の正常時には、電動モータ１０の制御には、メイン系統から出力される電圧信号が用いられる。サブ系統から出力される電圧信号は、電動モータ１０の制御には用いられず、トルクセンサ１２の故障を判定するために用いられる。 When the torque sensor 12 is normal, a voltage signal output from the main system is used to control the electric motor 10. The voltage signal output from the sub system is not used for controlling the electric motor 10 but is used for determining a failure of the torque sensor 12.

　故障判定部３２は、メイン系統から出力された出力電圧とサブ系統から出力された出力電圧とを比較し、その差が予め定められた許容差以上であると判断した場合には、トルクセンサ１２が故障していると判定する。 The failure determination unit 32 compares the output voltage output from the main system and the output voltage output from the sub system, and determines that the difference is greater than or equal to a predetermined tolerance, the torque sensor 12 Is determined to be malfunctioning.

　次に、図１及び２を参照して、電動パワーステアリング装置１００によるステアリング制御について説明する。 Next, steering control by the electric power steering apparatus 100 will be described with reference to FIGS.

　故障判定部３２がトルクセンサ１２の正常を判定している間は、モータ制御部３１は、トルクセンサ１２の検出結果に基づいて電動モータ１０の駆動を制御する。 While the failure determination unit 32 determines that the torque sensor 12 is normal, the motor control unit 31 controls the drive of the electric motor 10 based on the detection result of the torque sensor 12.

　トルクセンサ１２のメイン系統から出力された出力電圧とサブ系統から出力された出力電圧との差が予め定められた許容差以上となり故障判定部３２がトルクセンサ１２の故障を判定した場合には、モータ制御部３１は、トルクセンサ１２の検出結果に基づくアシスト制御から、操舵角センサ１５の検出結果に基づく転舵角制御へと、電動モータ１０の制御方法を切り換える。以下に、トルクセンサ１２の故障時における転舵角制御について説明する。 When the difference between the output voltage output from the main system of the torque sensor 12 and the output voltage output from the sub system is equal to or greater than a predetermined tolerance, and the failure determination unit 32 determines that the torque sensor 12 has failed, The motor control unit 31 switches the control method of the electric motor 10 from assist control based on the detection result of the torque sensor 12 to turning angle control based on the detection result of the steering angle sensor 15. Below, turning angle control at the time of failure of the torque sensor 12 is demonstrated.

　モータ制御部３１は、操舵角センサ１５の検出結果に基づいて車輪６の目標転舵角を設定する。一方、転舵角取得部３３は、モータ回転角センサ１０ａの検出結果に基づいて車輪６の実際の転舵角を演算する。具体的には、転舵角取得部３３は、モータ回転角センサ１０ａの検出結果及び減速機１１の減速比に基づいて出力シャフト３の回転角度を演算し、出力シャフト３の回転角度及びピニオンギヤ３ａとラックギヤ５ａの減速比からラック軸５の軸方向への移動量を演算し、その移動量に基づいて車輪６の実際の転舵角を演算する。そして、モータ制御部３１は、転舵角取得部３３で取得された車輪６の実際の転舵角が目標転舵角に一致するように、電動モータ１０の駆動を制御する。 The motor control unit 31 sets the target turning angle of the wheel 6 based on the detection result of the steering angle sensor 15. On the other hand, the turning angle acquisition unit 33 calculates the actual turning angle of the wheel 6 based on the detection result of the motor rotation angle sensor 10a. Specifically, the turning angle acquisition unit 33 calculates the rotation angle of the output shaft 3 based on the detection result of the motor rotation angle sensor 10a and the reduction ratio of the speed reducer 11, and the rotation angle of the output shaft 3 and the pinion gear 3a. And the amount of movement of the rack shaft 5 in the axial direction is calculated from the reduction ratio of the rack gear 5a, and the actual turning angle of the wheel 6 is calculated based on the amount of movement. And the motor control part 31 controls the drive of the electric motor 10 so that the actual turning angle of the wheel 6 acquired by the turning angle acquisition part 33 may correspond with a target turning angle.

　このように、トルクセンサ１２の故障時には、トルクセンサ１２の検出結果に基づくアシスト制御から、ステアリング操作に伴うステアリングホイール１の操舵角に基づく転舵角制御へと切り換えられる。トルクセンサ１２の故障時における転舵角制御では、運転者がステアリングホイール１を切り始めた直後は、トーションバー４が捩じれるため、ステアリングホイール１の操舵がそれほど重くならずステアリングホイール１が数度回転する。ステアリングホイール１が数度回転すれば、その回転角度が操舵角センサ１５によって検出されるため、モータ制御部３１にて目標転舵角が設定されて電動モータ１０が制御される。したがって、ステアリングホイール１とラック軸５が機械的に接続された電動パワーステアリング装置１００であっても、転舵角制御が可能となる。 Thus, when the torque sensor 12 fails, the assist control based on the detection result of the torque sensor 12 is switched to the turning angle control based on the steering angle of the steering wheel 1 accompanying the steering operation. In the turning angle control at the time of failure of the torque sensor 12, immediately after the driver starts turning the steering wheel 1, the torsion bar 4 is twisted, so that the steering of the steering wheel 1 is not so heavy and the steering wheel 1 is several times. Rotate. If the steering wheel 1 rotates several degrees, the rotation angle is detected by the steering angle sensor 15, so the target turning angle is set by the motor control unit 31 and the electric motor 10 is controlled. Therefore, even in the electric power steering apparatus 100 in which the steering wheel 1 and the rack shaft 5 are mechanically connected, the turning angle control is possible.

　以上の実施形態によれば、以下に示す効果を奏する。 According to the above embodiment, the following effects are obtained.

　トルクセンサ１２の故障時には、転舵角取得部３３にて取得された車輪６の実際の転舵角が操舵角センサ１５の検出結果に基づいて設定された目標転舵角に一致するように、電動モータ１０の駆動が制御される。このように、トルクセンサ１２の故障時には、アシスト制御ではなく、ステアリング操作に伴うステアリングホイール１の操舵角に基づいて転舵角制御が行われる。転舵角制御では、運転者のステアリング操作に伴って目標転舵角が設定され、車輪６の実際の転舵角が目標転舵角に一致するように電動モータ１０の駆動が制御されるため、トルクセンサ１２の故障時の操舵フィーリングを向上させることができる。 When the torque sensor 12 fails, the actual turning angle of the wheel 6 acquired by the turning angle acquisition unit 33 matches the target turning angle set based on the detection result of the steering angle sensor 15. The drive of the electric motor 10 is controlled. Thus, when the torque sensor 12 is out of order, not the assist control but the turning angle control is performed based on the steering angle of the steering wheel 1 accompanying the steering operation. In the turning angle control, the target turning angle is set in accordance with the steering operation of the driver, and the drive of the electric motor 10 is controlled so that the actual turning angle of the wheel 6 matches the target turning angle. Further, it is possible to improve the steering feeling when the torque sensor 12 fails.

　以下、本発明の実施形態の構成、作用、及び効果をまとめて説明する。 Hereinafter, the configuration, operation, and effect of the embodiment of the present invention will be described together.

　本実施形態では、電動パワーステアリング装置１００は、運転者によるステアリング操作に伴って回転する入力シャフト２と、車輪６を転舵するラック軸５に連係する出力シャフト３と、入力シャフト２と出力シャフト３を連結するトーションバー４と、トーションバー４に作用するトルクを検出するトルクセンサ１２と、トルクセンサ１２の正常時に、トルクセンサ１２の検出結果に基づいて運転者によるステアリング操作を補助する操舵補助トルクを付与する電動モータ１０と、トルクセンサ１２の故障を判定する故障判定部３２と、ステアリング操作に伴う操舵角を取得する操舵角センサ１５と、車輪６の転舵角を取得する転舵角取得部３３と、故障判定部３２がトルクセンサ１２の故障を判定した場合には、操舵角センサ１５の取得結果に基づいて車輪６の目標転舵角を設定し、転舵角取得部３３にて取得された転舵角が目標転舵角に一致するように電動モータ１０の駆動を制御するモータ制御部３１と、を備える。 In the present embodiment, the electric power steering apparatus 100 includes an input shaft 2 that rotates in accordance with a steering operation by a driver, an output shaft 3 that is linked to a rack shaft 5 that steers wheels 6, an input shaft 2, and an output shaft. 3, a torque sensor 12 that detects torque acting on the torsion bar 4, and a steering assist that assists the driver in steering operation based on the detection result of the torque sensor 12 when the torque sensor 12 is normal. The electric motor 10 that applies torque, the failure determination unit 32 that determines failure of the torque sensor 12, the steering angle sensor 15 that acquires the steering angle associated with the steering operation, and the turning angle that acquires the turning angle of the wheel 6 When the acquisition unit 33 and the failure determination unit 32 determine that the torque sensor 12 has failed, the acquisition of the steering angle sensor 15 can be performed. A motor control unit that sets the target turning angle of the wheel 6 based on the result and controls the drive of the electric motor 10 so that the turning angle acquired by the turning angle acquisition unit 33 matches the target turning angle. 31.

　この構成では、トルクセンサ１２の故障時には、転舵角取得部３３にて取得された転舵角が操舵角センサ１５の取得結果に基づいて設定された目標転舵角に一致するように電動モータ１０の駆動が制御される。このように、トルクセンサ１２の故障時には、アシスト制御ではなく、ステアリング操作に伴う操舵角に基づいて転舵角制御が行われる。よって、トルクセンサ故障時の操舵フィーリングを向上させることができる。 In this configuration, when the torque sensor 12 fails, the electric motor is set such that the turning angle acquired by the turning angle acquisition unit 33 matches the target turning angle set based on the acquisition result of the steering angle sensor 15. 10 drive is controlled. Thus, when the torque sensor 12 fails, the turning angle control is performed based on the steering angle associated with the steering operation, not the assist control. Therefore, it is possible to improve the steering feeling when the torque sensor fails.

　以上、本発明の実施形態について説明したが、上記実施形態は本発明の適用例の一部を示したに過ぎず、本発明の技術的範囲を上記実施形態の具体的構成に限定する趣旨ではない。 The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

　例えば、上記実施形態では、出力シャフト３の下部に形成されたピニオンギヤ３ａがラック軸５に形成されたラックギヤ５ａと噛み合う形態について説明した。これに代わり、出力シャフト３とは別にラックギヤ５ａに噛み合うピニオンシャフトを設け、出力シャフト３とピニオンシャフトを自在継手を介して連結するように構成してもよい。 For example, in the above-described embodiment, the form in which the pinion gear 3 a formed at the lower part of the output shaft 3 meshes with the rack gear 5 a formed on the rack shaft 5 has been described. Instead of this, a pinion shaft that meshes with the rack gear 5a may be provided separately from the output shaft 3, and the output shaft 3 and the pinion shaft may be connected via a universal joint.

　上記実施形態では、操舵角センサ１５の検出結果に基づいて車輪６の目標転舵角を設定する形態について説明した。これに代わり、操舵角センサ１５の検出結果に加えて車速情報等も考慮すれば、より精度の高い目標転舵角を設定することができる。 In the above embodiment, the mode in which the target turning angle of the wheel 6 is set based on the detection result of the steering angle sensor 15 has been described. Instead of this, if the vehicle speed information and the like are taken into account in addition to the detection result of the steering angle sensor 15, a more accurate target turning angle can be set.

　上記実施形態では、転舵角取得部３３は、モータ回転角センサ１０ａの検出結果に基づいて車輪６の実際の転舵角を演算する形態について説明した。これに代わり、車輪６の実際の転舵角を検出する転舵角センサを設け、演算ではなく車輪６の実際の転舵角を直接取得するように構成してもよい。 In the above embodiment, the turning angle acquisition unit 33 has been described with respect to the form of calculating the actual turning angle of the wheel 6 based on the detection result of the motor rotation angle sensor 10a. Instead of this, a turning angle sensor for detecting the actual turning angle of the wheel 6 may be provided, and the actual turning angle of the wheel 6 may be directly acquired instead of the calculation.

　本願は２０１５年６月１９日に日本国特許庁に出願された特願２０１５－１２３７０４に基づく優先権を主張し、この出願の全ての内容は参照により本明細書に組み込まれる。 This application claims priority based on Japanese Patent Application No. 2015-123704 filed with the Japan Patent Office on June 19, 2015, the entire contents of which are incorporated herein by reference.

Claims (4)

　運転者によるステアリング操作に伴って回転する入力シャフトと、
　車輪を転舵するラック軸に連係する出力シャフトと、
　前記入力シャフトと前記出力シャフトを連結するトーションバーと、
　前記トーションバーに作用するトルクを検出するトルクセンサと、
　前記トルクセンサの正常時に、前記トルクセンサの検出結果に基づいて運転者によるステアリング操作を補助する操舵補助トルクを付与する電動モータと、
　前記トルクセンサの故障を判定する故障判定部と、
　ステアリング操作に伴う操舵角を取得する操舵角取得部と、
　前記車輪の転舵角を取得する転舵角取得部と、
　前記故障判定部が前記トルクセンサの故障を判定した場合には、前記操舵角取得部の取得結果に基づいて前記車輪の目標転舵角を設定し、前記転舵角取得部にて取得された転舵角が前記目標転舵角に一致するように前記電動モータの駆動を制御するモータ制御部と、を備える電動パワーステアリング装置。 An input shaft that rotates in accordance with the steering operation by the driver;
An output shaft linked to the rack shaft that steers the wheels;
A torsion bar connecting the input shaft and the output shaft;
A torque sensor for detecting torque acting on the torsion bar;
An electric motor for applying a steering assist torque for assisting a steering operation by a driver based on a detection result of the torque sensor when the torque sensor is normal;
A failure determination unit for determining a failure of the torque sensor;
A steering angle acquisition unit for acquiring a steering angle associated with a steering operation;
A turning angle acquisition unit for acquiring a turning angle of the wheel;
When the failure determination unit determines that the torque sensor has failed, the target turning angle of the wheel is set based on the acquisition result of the steering angle acquisition unit, and is acquired by the turning angle acquisition unit. An electric power steering apparatus comprising: a motor control unit that controls driving of the electric motor such that a turning angle coincides with the target turning angle. 　前記操舵角取得部は、前記入力シャフトに設けられ前記入力シャフトの回転角度を取得する請求項１に記載の電動パワーステアリング装置。 The electric power steering apparatus according to claim 1, wherein the steering angle acquisition unit is provided on the input shaft and acquires a rotation angle of the input shaft. 　前記転舵角取得部は、前記電動モータの回転角度を検出するモータ回転角検出部の検出結果に基づいて前記車輪の転舵角を演算する請求項１に記載の電動パワーステアリング装置。 The electric power steering apparatus according to claim 1, wherein the turning angle acquisition unit calculates a turning angle of the wheel based on a detection result of a motor rotation angle detection unit that detects a rotation angle of the electric motor. 　前記電動モータの回転を前記出力シャフトに減速して伝達する減速機と、
　ラック軸に形成されたラックギヤと噛み合うピニオンギヤと、をさらに備え、
　前記転舵角取得部は、前記モータ回転角検出部の検出結果及び前記減速機の減速比に基づいて前記出力シャフトの回転角度を演算し、前記出力シャフトの回転角度及び前記ピニオンギヤと前記ラックギヤの減速比から前記ラック軸の軸方向への移動量を演算し、その移動量に基づいて前記車輪の転舵角を演算する請求項３に記載の電動パワーステアリング装置。 A decelerator that decelerates and transmits the rotation of the electric motor to the output shaft;
A pinion gear that meshes with a rack gear formed on the rack shaft,
The turning angle acquisition unit calculates a rotation angle of the output shaft based on a detection result of the motor rotation angle detection unit and a reduction ratio of the speed reducer, and calculates the rotation angle of the output shaft, the pinion gear, and the rack gear. The electric power steering apparatus according to claim 3, wherein an amount of movement of the rack shaft in the axial direction is calculated from a reduction ratio, and a turning angle of the wheel is calculated based on the amount of movement.
PCT/JP2016/067269 2015-06-19 2016-06-09 Electric power steering device Ceased WO2016204072A1 (en)

Applications Claiming Priority (2)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006143151A (en) * 2004-11-24 2006-06-08 Honda Motor Co Ltd Electric power steering device
JP2007062466A (en) * 2005-08-30 2007-03-15 Nissan Motor Co Ltd Vehicle steering shaft rotation abnormal range determination device and steering shaft rotation abnormal range determination method
JP2009012511A (en) * 2007-07-02 2009-01-22 Nsk Ltd Electric power steering device
JP2012101674A (en) * 2010-11-10 2012-05-31 Honda Motor Co Ltd Electric power steering system
JP2014004920A (en) * 2012-06-25 2014-01-16 Toyota Motor Corp Electric power steering apparatus for vehicle

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006143151A (en) * 2004-11-24 2006-06-08 Honda Motor Co Ltd Electric power steering device
JP2007062466A (en) * 2005-08-30 2007-03-15 Nissan Motor Co Ltd Vehicle steering shaft rotation abnormal range determination device and steering shaft rotation abnormal range determination method
JP2009012511A (en) * 2007-07-02 2009-01-22 Nsk Ltd Electric power steering device
JP2012101674A (en) * 2010-11-10 2012-05-31 Honda Motor Co Ltd Electric power steering system
JP2014004920A (en) * 2012-06-25 2014-01-16 Toyota Motor Corp Electric power steering apparatus for vehicle

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