WO2023079691A1 - Dispositif de direction assistée électrique - Google Patents

Dispositif de direction assistée électrique Download PDF

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Publication number
WO2023079691A1
WO2023079691A1 PCT/JP2021/040815 JP2021040815W WO2023079691A1 WO 2023079691 A1 WO2023079691 A1 WO 2023079691A1 JP 2021040815 W JP2021040815 W JP 2021040815W WO 2023079691 A1 WO2023079691 A1 WO 2023079691A1
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WIPO (PCT)
Prior art keywords
steering
angle
vehicle
amount
correction
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PCT/JP2021/040815
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English (en)
Japanese (ja)
Inventor
光太郎 岡田
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株式会社ジェイテクト
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Application filed by 株式会社ジェイテクト filed Critical 株式会社ジェイテクト
Priority to PCT/JP2021/040815 priority Critical patent/WO2023079691A1/fr
Publication of WO2023079691A1 publication Critical patent/WO2023079691A1/fr

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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 disclosure relates to an electric power steering device.
  • cab-over type vehicles such as trucks where the driver's seat is located in front of the front axle, often use an axle-suspension type suspension in which the left and right wheels are connected by an axle.
  • a ball screw type steering gear box is often used in a vehicle having an axle suspension type.
  • the steering gearbox is mounted, for example, on a vehicle body frame.
  • the electric power steering device of Patent Document 1 has a motor and a ball screw type steering gear box.
  • the steering gearbox converts rotary motion of the steering shaft into swinging motion of the pitman arm.
  • the direction of the steered wheels is changed in conjunction with the pitman arm.
  • Torque of the motor is transmitted to the ball screw shaft of the steering gearbox via the speed reducer. This assists the steering of the steering wheel.
  • the vertical position of the body frame changes greatly depending on how the goods are loaded. Therefore, the vertical position of the steering gear box mounted on the body frame also changes. Since the pitman arm and the steered wheels are connected by a link mechanism, the steered position (steering angle) of the steered wheels changes according to the position change of the steering gear box. A similar phenomenon occurs when the vehicle accelerates or decelerates.
  • the relationship between the steering angle of the steering wheel and the steering angle of the steered wheels differs from the original relationship according to the steering angle ratio, which is the ratio of the steering angle of the steering wheel and the steering angle of the steered wheels, depending on the loading state of the goods or the running state of the vehicle. It is feared that this will change. For example, even though the rotational position of the steering wheel is the steering neutral position corresponding to the straight running state of the vehicle, the steered position of the steered wheels is different from the steering neutral position corresponding to the straight running state of the vehicle.
  • An electric power steering device applies torque to a steering mechanism of a vehicle.
  • the vehicle is configured such that the steered angle of the steered wheels changes according to the vehicle attitude.
  • the electric power steering device has a motor configured to generate the torque, and a steering control device configured to control the motor in accordance with a steering state. Based on the correlation between the vehicle attitude and the change in the steering angle, the steering control device corrects the change in the steering angle in accordance with the vehicle attitude detected by an on-vehicle sensor. is configured to control
  • FIG. 1 is a schematic diagram of an embodiment of an electric power steering device
  • FIG. FIG. 2 is a cross-sectional view of the steering gearbox of FIG. 1
  • FIG. 2 is a block diagram of a steering control device that controls the motor of FIG. 1
  • FIG. 2 is a side view of a vehicle equipped with the electric power steering device of FIG. 1
  • FIG. 2 is a schematic diagram showing sinking of the body frame of FIG. 1
  • 4 is a block diagram showing the configuration of the steering control device of FIG. 3
  • FIG. FIG. 6 is a graph showing the relationship between the amount of sinking of the body frame of FIG. 5 and the correction angle
  • FIG. FIG. 2 is a schematic diagram for explaining the process of correcting the steering angle of the steered wheels in FIG. 1;
  • an electric power steering device 20 is mounted on a cab-over type vehicle 10, for example.
  • the vehicle 10 has an axle suspension type suspension 11 .
  • a suspension 11 supports a front axle 12 .
  • Both ends of the front axle 12 are connected to steered wheels 13 which are front wheels.
  • the suspension 11 has leaf springs 14 .
  • the leaf spring 14 is positioned above the front axle 12 as an example.
  • the leaf spring 14 extends in the longitudinal direction of the vehicle. Both ends of the leaf spring 14 are attached to a vehicle body frame 16 via a support member 15 such as a shackle.
  • the electric power steering device 20 has a steering shaft 21, a steering gearbox 22, and a motor 23.
  • Steering shaft 21 and steering gear box 22 constitute a steering mechanism of vehicle 10 .
  • a first end of steering shaft 21 is connected to steering wheel 24 .
  • a second end of the steering shaft 21 is connected to a steering gearbox 22 .
  • the motor 23 is connected to the steering gear box 22 via a reduction gear 25 .
  • the steering gearbox 22 is, for example, of the RBS type (recirculating ball screw type).
  • the steering gearbox 22 is connected to the steered wheels 13 via the link mechanism 30 .
  • the link mechanism 30 has a pitman arm 31 , a drag link 32 and tie rods 33 .
  • a base end of the pitman arm 31 is connected to a side portion of the steering gear box 22 .
  • the pitman arm 31 can swing about its base end in the longitudinal direction of the vehicle.
  • a first end of the drag link 32 is rotatably connected to the tip of the pitman arm 31 .
  • a second end of the drag link 32 is rotatably connected to a knuckle arm 34 of the right steerable wheel 13 .
  • Both ends of the tie rod 33 are connected to the left and right steered wheels 13 via tie rod arms 35 .
  • the rotation of the steering wheel 24 is transmitted to the steering gear box 22 via the steering shaft 21.
  • the steering gearbox 22 converts the rotary motion of the steering shaft 21 into the swinging motion of the pitman arm 31 .
  • the swinging motion of the pitman arm 31 drives the drag link 32 in the longitudinal direction of the vehicle.
  • the steerable wheels 13 are steered by swinging of the knuckle arms 34 interlocking with the drag links 32 .
  • the motor 23 generates torque in the same direction as the steering direction of the steering wheel 24. Torque of the motor 23 is transmitted to the steering shaft 21 via the reduction gear 25 and steering gear box 22 . Thereby, the steering of the steering wheel 24 is assisted.
  • the steering gearbox 22 has a housing 40. As shown in FIG. A ball screw shaft 41 , a ball screw nut 42 , a plurality of balls 43 , a sector shaft 44 as an output shaft, and a sector gear 45 are provided inside the housing 40 .
  • the ball screw shaft 41 is rotatably supported with respect to the housing 40 via two bearings 46 and 47. A first end of the ball screw shaft 41 passes through the housing 40 and is exposed to the outside. A first end of the ball screw shaft 41 is connected to the steering wheel 24 via the steering shaft 21 . A second end of the ball screw shaft 41 opposite to the steering wheel 24 is connected to the reduction gear 25 .
  • the ball screw nut 42 is screwed onto the ball screw shaft 41 via a plurality of circulating balls 43 .
  • Rack teeth 42A are provided on the outer peripheral surface of the ball screw nut 42 so as to be aligned in the axial direction of the ball screw nut 42 .
  • the sector shaft 44 extends in a direction orthogonal to the axis of the ball screw nut 42 (perpendicular to the paper surface of FIG. 2).
  • the sector shaft 44 is rotatably supported with respect to the housing 40 via bearings (not shown).
  • the sector shaft 44 has an outer end that passes through the housing 40 and is exposed to the outside.
  • a base end of the pitman arm 31 is fixed to the outer end of the sector shaft 44 .
  • the sector gear 45 is provided so as to be integrally rotatable with respect to the sector shaft 44 .
  • the sector gear 45 is a sector gear and has a plurality of teeth 45A.
  • the teeth 45A of the sector gear 45 mesh with the rack teeth 42A of the ball screw nut 42. As shown in FIG.
  • the rotation of the steering wheel 24 is transmitted to the ball screw shaft 41 via the steering shaft 21.
  • the ball screw shaft 41 rotates, the ball screw nut 42 moves axially relative to the ball screw shaft 41 .
  • the sector gear 45 swings around the sector shaft 44 .
  • the pitman arm 31 swings around the sector shaft 44 .
  • the speed reducer 25 has a housing 50 .
  • the housing 50 is connected to the housing 40 of the steering gearbox 22 .
  • the insides of these housings 40 and 50 communicate with each other.
  • a motor 23 is attached to the outside of the housing 50 .
  • An output shaft 23A of the motor 23 extends in a direction perpendicular to the axis of the ball screw shaft 41 and parallel to the axis of the sector shaft 44. As shown in FIG.
  • An output shaft 23A of the motor 23 penetrates the housing 50 and is inserted inside the housing 50 .
  • a shaft 51 , a worm wheel 52 and a worm 53 are provided inside the housing 50 .
  • the shaft 51 is rotatably supported with respect to the housing 50 via two bearings 54 and 55 .
  • a first end of the shaft 51 is connected to a second end of the ball screw shaft 41 so as to rotate together.
  • a gap is provided between the second end of the shaft 51 and the housing 50 .
  • the worm wheel 52 is provided rotatably with the shaft 51 .
  • the worm 53 is provided so as to be integrally rotatable with respect to the output shaft 23A of the motor 23 .
  • the axis of the output shaft 23A and the axis of the worm 53 coincide with each other.
  • the worm 53 meshes with the worm wheel 52 .
  • the torque of the motor 23 is transmitted to the ball screw shaft 41 via the reduction gear 25.
  • the steering of the steering wheel 24 is assisted by applying torque in the same direction as the steering direction of the steering wheel 24 to the ball screw shaft 41 .
  • the electric power steering device 20 has a steering control device 60 .
  • the steering control device 60 controls the motor 23 based on the detection result of the sensor.
  • the sensors include torque sensor 61 and rotation angle sensor 62 .
  • the torque sensor 61 is provided on the steering shaft 21 .
  • a torque sensor 61 detects a steering torque T h applied to the steering shaft 21 through the steering wheel 24 .
  • the rotation angle sensor 62 is provided on the motor 23 .
  • a rotation angle sensor 62 detects the rotation angle ⁇ m of the motor 23 .
  • the steering control device 60 controls power supply to the motor 23 based on the steering torque T h detected by the torque sensor 61 and the rotation angle ⁇ m detected by the rotation angle sensor 62 .
  • the vehicle 10 may have a driving support function for improving safety or convenience, or an automatic driving function in which the system substitutes for driving.
  • the vehicle 10 has a host controller 70 .
  • the host control device 70 centrally controls control devices of various in-vehicle systems including the electric power steering device 20 .
  • the host control device 70 determines the optimum control method based on the state of the vehicle at that time, and issues individual control commands to various control devices according to the control method that is determined.
  • the host control device 70 intervenes in steering control by the steering control device 60 .
  • the host controller 70 switches the automatic driving function between ON and OFF, for example, based on the operation of a switch provided in the driver's seat.
  • Automated driving functions also include driving assistance functions.
  • the host controller 70 calculates a target angle ⁇ * , which is a command value for causing the vehicle 10 to run on the target lane, for example, in a state where the automatic driving function is turned on.
  • the host controller 70 calculates the target angle ⁇ * according to the surrounding environment of the vehicle or the position of the vehicle.
  • the surrounding environment of the own vehicle is detected through a camera, for example.
  • the position (latitude, longitude) of the own vehicle is detected based on positioning signals from artificial satellites for GPS (Global Positioning System).
  • the target angle ⁇ * is a target value of the steering angle ⁇ s of the steering wheel 24, for example.
  • the steering control device 60 controls the motor 23 based on the target angle ⁇ * calculated by the host control device 70 .
  • Motor 23 and steering shaft 21 are connected to each other via steering gear box 22 and speed reducer 25 . Therefore, there is a correlation between the rotation angle ⁇ m of the motor 23 and the steering angle ⁇ s . Using this correlation, the steering angle ⁇ s can be obtained from the rotation angle ⁇ m of the motor 23 .
  • the steering control device 60 obtains the difference between the steering angle ⁇ s calculated based on the rotation angle ⁇ m of the motor 23 and the target angle ⁇ * , and controls power supply to the motor 23 so as to eliminate this difference.
  • the vehicle 10 is, for example, a truck having an article loading facility 10A.
  • the value of the vertical load F1 applied to the vehicle body changes depending on how the articles are loaded.
  • the vehicle 10 has an axle suspension type suspension 11 (see FIG. 1).
  • the deflection amount of the leaf spring 14 of the suspension 11 changes according to the loaded state of the articles.
  • the vertical position of the vehicle body frame 16 changes according to the amount of deflection of the leaf spring 14 .
  • the deflection amount of the leaf spring 14 increases.
  • the body frame 16 sinks downward according to the deflection amount of the leaf spring 14 .
  • the steering gearbox 22 is mounted on the vehicle body frame 16 . Therefore, the vertical position of the steering gear box 22 also changes according to the vertical position change of the vehicle body frame 16 . Therefore, in the vehicle 10, we are concerned about the following. That is, since the pitman arm 31 and the steered wheels 13 are connected by the link mechanism 30, the steered position (steering angle ⁇ w ) of the steered wheels 13 changes according to the vertical position change of the steering gear box 22. Change.
  • the relationship between the steering angle ⁇ s of the steering wheel 24 and the steering angle ⁇ w of the steerable wheels 13 differs from the original relationship according to the steering angle ratio, which is the ratio of the steering angle ⁇ s of the steering wheel 24 and the steering angle ⁇ w of the steered wheels 13, depending on the loading state of the articles in the vehicle 10.
  • the steering angle ratio which is the ratio of the steering angle ⁇ s of the steering wheel 24 and the steering angle ⁇ w of the steered wheels 13, depending on the loading state of the articles in the vehicle 10.
  • the steering control device 60 is configured as follows. ⁇ Detailed Configuration of Steering Control Device> As shown in FIG. 6, the steering control device 60 has a microcomputer 60A and a drive circuit 60B. The drive circuit 60B supplies drive power to the motor 23 according to the current command value I * calculated by the microcomputer 60A.
  • the microcomputer 60A has an assist control amount calculator 71, a correction amount calculator 72, a first adder 73, a steering angle calculator 74, an automatic driving control amount calculator 75, and a second adder 76. there is These arithmetic units are functional parts realized by the CPU (Central Processing Unit) of the microcomputer 60A executing the control program.
  • Microcomputer 60A includes a memory that stores control programs. Memory includes computer-readable media such as random access memory (RAM) and read only memory (ROM). However, it is only an example that each calculation unit is realized by software, and at least a part of the calculation unit may be realized by hardware such as a logic circuit.
  • the steering control device 60 includes (1) one or more processors that operate according to a computer program (software), (2) one or more dedicated hardware circuits that execute at least part of various types of processing, or (3) a combination thereof.
  • the host control device 70 can also be configured as a processing circuit having the same configuration as the steering control device 60 .
  • the assist control amount calculator 71 calculates an assist control amount I 1 * based on the steering torque Th detected through the torque sensor 61 .
  • the assist control amount I 1 * indicates the amount of current to be supplied to the motor 23 in order to cause the motor 23 to generate an assist torque corresponding to the steering torque Th .
  • the assist control amount calculation unit 71 calculates the assist control amount I 1 * having a larger absolute value as the absolute value of the steering torque T h increases.
  • the assist control amount calculation section 71 corresponds to a first calculation section or a first calculation circuit.
  • the assist control amount I 1 * corresponds to the first control amount.
  • the correction amount calculator 72 operates only while the automatic operation function is on.
  • the correction amount calculation unit 72 calculates a correction angle ⁇ c , which is a correction amount for the target angle ⁇ * , according to the loading state of the articles on the vehicle 10 .
  • the correction amount calculator 72 calculates the correction angle ⁇ c using the correction map Mc .
  • the correction map Mc is stored in the storage section 72A of the correction amount calculation section 72.
  • the correction map Mc has the following characteristics, with the horizontal axis representing the sinking amount L1 of the vehicle body frame 16 and the vertical axis representing the absolute value of the correction angle ⁇ c . That is, as the sinking amount L1 of the vehicle body frame 16 increases, the absolute value of the correction angle ⁇ c is set to a larger value. This is because the amount of change in the steering angle ⁇ w increases as the sinking amount L1 of the body frame 16 increases.
  • the correction angle ⁇ c is set to the steering angle ⁇ w corresponding to the sinking amount L1 of the body frame 16. is assigned a sign opposite to the direction of change of .
  • the steering angle of the steerable wheels 13 changes to the right with respect to the steering neutral position as the steering gear box 22 descends. Therefore, for example, when the right steering direction with reference to the steering neutral position is positive and the left steering direction is negative, the correction angle ⁇ c is given a negative sign.
  • the correction map Mc is set by the following procedures (A1) and (A2), for example, through experiments using an actual vehicle or computer simulation.
  • (A1) First, the relationship between the loading state of the articles on the vehicle 10 and the sinking amount L1 of the body frame 16 is grasped. For example, when the steered position of the steered wheels 13 is maintained at the steered neutral position and the load amount of the goods is changed within the range from 0 to the maximum load amount for each unit load amount, each load amount of the goods is detected.
  • the steered neutral position is a steered position of the steered wheels 13 corresponding to the straight running state of the vehicle 10 .
  • the sinking amount L1 is the amount of displacement of the body frame 16 with reference to the position of the body frame 16 when the load of the article is zero.
  • the amount of displacement of the body frame 16 is the amount of change in the position of the steering gear box 22 on the body frame 16 at which the steering gear box 22 is mounted.
  • the amount of change in the steering angle ⁇ w with respect to the sinking amount L1 for each load amount of articles is grasped.
  • the amount of change in the steering angle ⁇ w with respect to the amount of depression L1 is determined by the mechanical restraint conditions of the steered wheels 13 by the link mechanism 30 .
  • the amount of change in the steered angle ⁇ w is the amount of change in the steered angle ⁇ w with respect to the steered neutral position of the steered wheels 13 .
  • the amount of correction of the turning angle ⁇ w required for correcting the steering angle ⁇ w can be obtained for each load amount of articles. Since there is a correlation between the steering angle ⁇ w and the steering angle ⁇ s , the steering angle ⁇ w is corrected to an angle corresponding to the straight running state of the vehicle 10 from the correction amount of the steering angle ⁇ w.
  • a correction angle ⁇ c that is a correction amount of the steering angle ⁇ s required for the load can be obtained for each load amount of articles.
  • the correction amount calculator 72 monitors the actual loading state of the vehicle 10 .
  • the correction amount calculation unit 72 recognizes the loading state of the articles based on the sinking amount L1 of the vehicle body frame 16 detected by the vehicle-mounted sensor 63 .
  • the sensor 63 is, for example, a vehicle height sensor that detects the movement of the suspension 11, and is provided on each of the front, rear, left, and right wheels including the steered wheels 13 of the vehicle.
  • the correction amount calculator 72 calculates the correction angle ⁇ c based on the sinking amount L1 of the body frame 16 detected by the sensor 63 and using the correction map Mc shown in the graph of FIG.
  • the sinking amount L1 of the vehicle body frame 16 is a state variable that reflects the vehicle attitude.
  • the correction amount calculator 72 corresponds to a third calculator or a third calculator.
  • the first adder 73 adds the target angle ⁇ * calculated by the host controller 70 and the correction angle ⁇ c calculated by the correction amount calculation unit 72 to obtain the final target angle ⁇ f *. to calculate
  • a steering angle calculator 74 calculates a steering angle ⁇ s that is the rotation angle of the steering wheel 24 based on the rotation angle ⁇ m of the motor 23 detected by the rotation angle sensor 62 .
  • the steering angle calculator 74 counts the number of rotations of the motor 23 with reference to the steering neutral position of the steering wheel 24 corresponding to the straight running state of the vehicle, for example, and calculates the absolute value of the rotation angle ⁇ m of multiple rotations exceeding 360°. Calculate.
  • the steering angle calculator 74 calculates the steering angle ⁇ s by multiplying the rotation angle ⁇ m of the motor 23 by a conversion coefficient based on the reduction ratio between the motor 23 and the steering shaft 21 .
  • the automatic driving control amount calculator 75 operates only while the automatic driving function is on.
  • the automatic driving control amount calculator 75 takes in the final target angle ⁇ f * calculated by the first adder 73 and the steering angle ⁇ s of the steering wheel 24 calculated by the steering angle calculator 74 .
  • the automatic driving control amount calculation unit 75 calculates the automatic driving control amount I 2 * through execution of feedback control that causes the steering angle ⁇ s to follow the final target angle ⁇ f * .
  • the automatic operation control amount I 2 * is calculated by performing proportional calculation, integral calculation and differential calculation on the calculated deviation ⁇ . That is, the automatic driving control amount I 2 * is the sum of the output value of the proportional element whose input is the deviation ⁇ , the output value of the integral element whose input is the deviation ⁇ , and the output value of the differential element whose input is the deviation ⁇ . is.
  • the automatic driving control amount I 2 * indicates the amount of current to be supplied to the motor 23 to cause the steering angle ⁇ s calculated by the steering angle calculator 74 to follow the final target angle ⁇ f * .
  • the automatic operation control amount calculation section 75 corresponds to a second calculation section or a second calculation circuit.
  • the automatic driving control amount I 2 * corresponds to the second control amount.
  • the second adder 76 calculates a current command value I * for the motor 23 by adding the assist control amount I1 * and the automatic operation control amount I2 * .
  • the target angle ⁇ * calculated by the host controller 70 is not corrected.
  • the steered wheels 13 are steered with respect to the steered neutral position according to the loaded state of the articles.
  • the state is shifted to the right by an angle ⁇ w . That is, the steering angle ⁇ w corresponding to the target angle ⁇ * cannot be obtained. Therefore, even if the rotational position of the steering wheel 24 is controlled to the steering neutral position corresponding to the straight running state of the vehicle 10, the vehicle 10 does not run straight. That is, the vehicle 10 travels in the direction in which the steered wheels 13 are displaced according to the loaded state of the articles.
  • the steering angle ⁇ w of the steerable wheels 13 is corrected according to the loaded state of the articles. Specifically, a correction angle ⁇ c corresponding to the loading state of the articles is added to the target angle ⁇ * .
  • the correction angle ⁇ c is set from the viewpoint of canceling out the steering angle ⁇ w corresponding to the displacement of the steerable wheels 13 according to the loaded state of the articles.
  • the target angle ⁇ * is an angle corresponding to the straight running state of the vehicle 10
  • a correction angle ⁇ c for turning the steered wheels 13 to the left by an angle ⁇ w is added to the target angle ⁇ * .
  • the final target angle ⁇ f * is calculated.
  • the steering control device 60 detects the vehicle body position through the vehicle-mounted sensor 63 based on the correlation between the amount of sinking L1 of the body frame 16 that indicates one of the vehicle attitudes and the change in the steering angle ⁇ w .
  • the motor 23 is controlled so as to correct the change in the steering angle ⁇ w according to the sinking amount L1 of the frame 16 . Therefore, the influence of the sinking amount L1 of the vehicle body frame 16 on the steering angle ⁇ w and thus on the behavior of the vehicle 10 can be suppressed.
  • the sinking amount L1 of the vehicle body frame 16 changes according to the loading state of articles or the running state of the vehicle 10 .
  • a change in the steering angle ⁇ w is corrected in accordance with the amount of sinking L1 of the vehicle body frame 16 . Therefore, it is possible to suppress the influence of the loading state of the articles or the driving state of the vehicle 10 on the turning angle ⁇ w .
  • the steering control device 60 determines the steering angle ⁇ according to the sinking amount L1 based on the sinking amount L1 of the body frame 16 detected by the sensor 63. Calculate a correction angle ⁇ c with respect to the target angle ⁇ * for correcting the change in w .
  • the target angle ⁇ * is, for example, the target value of the steering angle ⁇ s .
  • the final target angle ⁇ f * is obtained by reflecting the correction angle ⁇ c in the target angle ⁇ * .
  • the steering control device 60 has a correction map Mc that defines the relationship between the sinking amount L1 of the body frame 16 and the correction angle ⁇ 1.
  • the correction map Mc By using the correction map Mc , the correction angle ⁇ c can be easily obtained based on the sinking amount L1 of the vehicle body frame 16 .
  • the correction amount calculation unit 72 may operate even during a period in which the automatic driving function is turned off.
  • the correction amount calculator 72 calculates the correction control amount Ic according to the loading state of the articles while the automatic driving function is turned off.
  • the correction control amount Ic indicates the amount of current to be supplied to the motor 23 in order to cancel the steering angle ⁇ w corresponding to the displacement of the steerable wheels 13 according to the loaded state of the articles.
  • the absolute value of the correction control amount Ic is set to a larger value as the sinking amount L1 of the body frame 16 increases.
  • the second adder 76 calculates a current command value I * for the motor 23 by adding the assist control amount I1 * and the correction control amount Ic while the automatic driving function is turned off.
  • the second adder 76 calculates a current command value I * for the motor 23 by adding the assist control amount I1 * and the correction control amount Ic while the automatic driving function is turned off.
  • the correction amount calculation unit 72 may recognize the loading state of the articles based on the pitching motion of the vehicle 10 .
  • the pitching motion is a rotational motion about the left-right direction with respect to the traveling direction of the vehicle body. For example, when the brake is stepped on, the vehicle body leans forward, while when the brake is released, the rear portion of the vehicle body sinks in reaction. Pitching motion is also caused by road surface irregularities.
  • the pitch angle changes with the pitching motion.
  • the pitch angle is the angle at which the vehicle body is tilted about the horizontal direction with respect to the traveling direction of the vehicle body.
  • the pitch angle also changes depending on how the articles are loaded. Since the sinking amount L1 of the vehicle body frame 16 increases as the load of articles increases, the pitch angle tends to increase.
  • the correction amount calculator 72 calculates the correction angle ⁇ c or the correction control amount Ic according to the pitch angle detected by the pitch angle sensor mounted on the vehicle.
  • ⁇ A steering sensor may be mounted on the steering shaft 21 .
  • the steering sensor is an angle sensor that detects the steering angle ⁇ s of the steering wheel 24 .
  • the automatic driving control amount calculator 75 may calculate the automatic driving control amount I 2 * using the steering angle ⁇ s detected by the steering sensor.
  • the target angle ⁇ * calculated by the host controller 70 may be the target rotation angle of the motor 23 .
  • the correction amount calculation unit 72 calculates the correction angle ⁇ c for the target rotation angle of the motor 23 based on the sinking amount L1 of the body frame 16 detected by the sensor 63 .
  • the correction amount calculator 72 calculates the target rotation angle of the motor 23 using a correction map that defines the relationship between the sinking amount L1 of the body frame 16 and the absolute value of the correction angle ⁇ c with respect to the target rotation angle of the motor 23. Calculate the correction angle ⁇ c for .
  • the first adder 73 adds the target rotation angle of the motor 23 calculated by the host controller 70 and the correction angle ⁇ c calculated by the correction amount calculation unit 72 to obtain the final rotation angle of the motor 23. Calculate the target rotation angle.
  • the automatic driving control amount calculation unit 75 calculates the automatic driving control amount I 2 * through feedback control that causes the rotation angle ⁇ m of the motor 23 detected by the rotation angle sensor 62 to follow the final target rotation angle of the motor 23. Calculate.
  • the target angle ⁇ * calculated by the host controller 70 may be the target steering angle of the steerable wheels 13 .
  • the correction amount calculation unit 72 calculates the correction angle ⁇ c of the steerable wheels 13 with respect to the target turning angle based on the sinking amount L1 of the vehicle body frame 16 detected by the sensor 63 .
  • the correction amount calculation unit 72 uses a correction map that defines the relationship between the sinking amount L1 of the vehicle body frame 16 and the absolute value of the correction angle ⁇ c with respect to the target turning angle, and calculates the correction angle ⁇ with respect to the target turning angle. Compute c .
  • the first adder 73 adds the target turning angle calculated by the host controller 70 and the correction angle ⁇ c calculated by the correction amount calculating section 72 to obtain the final target turning angle. Calculate.
  • the automatic driving control amount calculation unit 75 performs automatic driving control amount I 2 * is calculated.
  • Vehicle 10 may have an independent suspension type suspension that supports each wheel independently.
  • the type of steering gearbox 22 is not limited to the RBS type.
  • the steering gearbox 22 may be, for example, a rack and pinion steering gearbox.
  • the suspension that supports at least one of the left and right steered wheels 13 sinks relative to the steered wheels 13 due to the inertial force thereof. w may change.
  • the steering angle ⁇ w of the sinking of the suspension supporting the steered wheels 13 can suppress the influence of

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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)

Abstract

Ce dispositif de direction assistée électrique (20) applique un couple à un mécanisme de direction d'un véhicule (10). Le véhicule (10) est conçu de telle sorte qu'un angle de braquage (θw) de roues braquées (13) change selon une orientation de véhicule (L1). Le dispositif de direction assistée électrique (20) comporte un moteur (23) qui génère un couple et un dispositif de commande de direction (60) qui commande le moteur (23) en fonction d'un état de direction. Le dispositif de commande de direction (60) est conçu pour commander le moteur (23) de manière à corriger le changement de l'angle de braquage (θw) conformément à une orientation de véhicule (L1) détectée par l'intermédiaire d'un capteur embarqué (63), sur la base de la corrélation entre l'orientation du véhicule (L1) et le changement de l'angle de braquage (θw).
PCT/JP2021/040815 2021-11-05 2021-11-05 Dispositif de direction assistée électrique WO2023079691A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007001564A (ja) * 2005-05-26 2007-01-11 Nsk Ltd ステアバイワイヤシステム
JP2013164292A (ja) * 2012-02-09 2013-08-22 Advics Co Ltd 操舵輪軸重推定装置
JP2016501775A (ja) * 2012-12-20 2016-01-21 ボルボ トラック コーポレイション 電気操舵システムのための方法及び装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007001564A (ja) * 2005-05-26 2007-01-11 Nsk Ltd ステアバイワイヤシステム
JP2013164292A (ja) * 2012-02-09 2013-08-22 Advics Co Ltd 操舵輪軸重推定装置
JP2016501775A (ja) * 2012-12-20 2016-01-21 ボルボ トラック コーポレイション 電気操舵システムのための方法及び装置

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