JP2006240443A - Wheel steering system, and steering reaction force control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel steering system and a steering reaction force control method capable of controlling the fluctuation of the steering reaction force attributable to the disturbance such as the kickback according to a driver. <P>SOLUTION: In the wheel steering system to steer wheels according to the operational quantity of a steering wheel, the magnitude of the external force received by a wheel transmitted to the steering wheel via an external force transmission means is controlled according to information on the arm mass of a driver. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wheel steering system that steers a wheel according to an operation amount of a steering wheel, and a steering reaction force control method that controls the magnitude of a steering reaction force that a driver receives from a steering wheel.

  2. Description of the Related Art Today, a steering apparatus for a vehicle such as an automobile is generally equipped with a power assist device using a hydraulic type or an electric motor (so-called power steering system). In a steering device for a vehicle such as an automobile, the steering feeling (steering reaction force characteristic) that the driver recognizes mainly through the touch feeling of the hand or arm via the steering wheel has an appropriate characteristic according to the driver. Is preferred. Conventionally, there has been proposed a power assist device having a function of detecting a driver's posture and muscle strength and optimizing a steering reaction force characteristic according to the driver.

For example, in the following Patent Document 1, by detecting the driver's sitting posture and the driver's physique, and controlling the assist rate in the power assist device according to the information on the sitting posture and the physique, An electric power steering apparatus is disclosed in which a driver obtains an appropriate steering feeling. In Patent Document 2 below, the electric power that detects the driver's physique and posture and controls the assist rate in accordance with the information on the physique and posture allows the driver to always obtain a good steering feeling. A steering device is disclosed. These Patent Literatures 1 and 2 focus on the steering reaction force when the driver actively steers the wheel by operating the steering wheel (changing or correcting the direction of the vehicle). The steering reaction force in the active operation of the steering wheel by the driver is suitably adjusted according to the driver. On the other hand, Patent Document 3 below proposes an electric steering device that suppresses and prevents fluctuations in the steering reaction force that occurs when an external force that a wheel receives from the road surface, such as kickback, is transmitted to the steering wheel. Fluctuation in steering reaction force due to disturbance such as kickback is necessary to some extent for the driver to grasp the road surface and vehicle (wheel) condition, but if it is too large, the driver cannot hold the steering wheel. There is also a problem that vehicle control (steering) becomes impossible. In Patent Document 3, the fluctuation of the steering reaction force due to such a kickback is suppressed and the driver can drive the vehicle (steer the wheel) with a good operation feeling.
JP-A-6-99829 JP-A-8-301136 JP 2004-168150 A

  By the way, when the vehicle is running straight ahead or the vehicle is cornering gently, it is not necessary to move the steering wheel suddenly or hold it firmly, The steering wheel is operated without using the muscle strength of the arm in a state where the steering wheel is gripped to release the arm force and the arm weight is applied to the steering wheel. This trend is getting stronger now that the performance of power steering devices has improved. If the vehicle wheel passes through the road surface unevenness or the saddle that the driver does not recognize, the steering reaction force fluctuation due to kickback suddenly occurs at a timing unexpected by the driver. In a driving state in which the steering wheel is operated without using arm strength, the driver cannot respond suddenly to the sudden change in steering reaction force due to an unexpected kickback. It will be moved greatly. Such fluctuations in the steering wheel vary depending on the mass of the driver's arm. This is because when the driver puts the arm mass on the steering wheel, the moment of the steering wheel (rotational moment about the steering shaft) takes into account the mass of the arm, and naturally the mass of the arm is heavy. This is because the moment of the steering wheel increases. In particular, in the case of a driver such as a woman who has a relatively thin arm and a light arm weight, this moment is reduced, and the steering is greatly shaken by an unexpected kickback, which greatly deteriorates the stability of the vehicle.

  In Patent Document 3 described above, fluctuations in the steering reaction force caused by disturbances such as kickback are suppressed and prevented according to the steering wheel steering amount and vehicle speed, but it is suggested that control is performed according to the driver. It has not been. Patent Document 1 and Patent Document 2 are inventions related to control of the assist rate of the power assist device, and do not describe suppression of fluctuations in steering reaction force due to disturbance such as kickback. Naturally, both of the cited document 1 and the cited document 2 are all about a specific method for controlling the fluctuation of the steering reaction force caused by disturbance such as kickback according to the driver, and parameters for the control. Not suggested.

  Therefore, in order to solve the above problem, the present invention provides a wheel steering system and a steering reaction force control method capable of controlling the fluctuation of the steering reaction force caused by disturbance such as kickback according to the driver. .

  In order to solve the above problems, the present invention provides a wheel steering system for steering a wheel in response to an operation of a steering wheel, the wheel acting to steer the wheel against the operation of the steering wheel. The external force transmitting means for transmitting the external force received by the steering wheel to the steering wheel, and the transmission for adjusting the magnitude of the transmitted external force transmitted to the steering wheel via the external force transmitting means according to the arm mass information of the driver A wheel steering system comprising an external force adjusting means is provided.

  The external force transmission means includes transmission external force reduction means for reducing the magnitude of the external force received by the wheel and transmitting the reduced force to the steering wheel. The transmission external force adjustment means is configured to transmit the transmission force based on the arm mass information. It is preferable to adjust the magnitude of the external force transmitted from the wheel side to the steering wheel by controlling the reduction rate of the external force in the external force reducing means.

  Moreover, it is preferable to provide arm mass information acquisition means for acquiring the driver's arm mass information. As the arm mass information acquisition means, a drive means for driving the steering wheel, a drag measurement means for measuring a resistance force applied to the driving of the steering wheel, and calculating the arm mass information based on the measured resistance force. Arm mass calculation means, and control means for controlling the operation of the drive means, the drag measurement means, and the arm mass calculation means, wherein the control means holds the steering wheel by the driver, In the state where the driver's arm weight is applied to the steering wheel, the driving means is driven to drive the steering wheel, and the resistance force at this time is measured by the drag measuring means, and based on the measured resistance force Preferably, the arm mass calculation means calculates the arm mass information.

  Further, the steering wheel and the wheel are mechanically connected via the external force transmission means, and further receives the operation of the steering wheel, and multiplies this operation force and transmits it to the wheel side. The transmission external force adjusting means controls the multiplication factor of the operating force in the power assist device based on the arm mass information, thereby controlling the external force transmitted from the wheel side to the steering wheel. It is preferable to adjust the size.

  According to the present invention, in the wheel steering in which the driver grips the steering wheel and steers the wheel by operating the rotation of the steering wheel, the magnitude of the steering reaction force that the driver receives from the steering wheel is determined. An operation reaction force characterized by controlling the magnitude of a disturbance-induced reaction force acting on the steering wheel according to an external force received by the wheel based on the arm mass information of the driver. A control method is also provided.

  According to the wheel steering system and the steering reaction force control method of the present invention, fluctuations in the steering reaction force caused by disturbance such as kickback can be moderately suppressed for each driver according to the driver's arm mass. . As a result, any driver can ensure the running stability of a vehicle such as an automobile driven by the driver, and can steer the wheel with a good steering feeling for each driver.

  Hereinafter, a wheel steering system and a steering reaction force control method of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

  FIG. 1 is a schematic configuration diagram of a wheel steering system 10 which is an example of a wheel steering system of the present invention. The wheel steering system 10 is a wheel steering system for passenger cars, and the driver operates the steering wheel 12 to control the turning angle of the wheel 14 to steer the wheel 14. The wheel steering device 10 includes a steering unit 16 that receives an operation of a steering wheel by a driver, and a steering unit 18 that steers the wheel 14 in accordance with an operation by the driver received by the steering unit 16. 16 and the steering unit 18 are connected via a power transmission mechanism 20. The wheel steering device 10 also includes arm mass information acquisition means 22 that measures the arm mass of the driver holding the steering wheel 12 and acquires the driver's arm mass information. The arm mass acquisition means 22 will be described in detail later. The wheel steering device 10 also includes control means 24 that receives various information sent from each part and controls the operation of each part based on the information. As the above-described power transmission mechanism 20, for example, when a steering unit and a steering unit are mechanically connected, such as a known rack and pinion type steering device, the steering shaft 40 that holds the steering wheel 12 is coupled. The main shaft corresponds to this. In the case of a steer-by-wire system (steer-by-wire system) in which the steering unit and the steering unit are mechanically separated to exchange information between the units, information transmission / reception between the steering unit and the steering unit is performed. Means correspond to this.

  The steering unit 16 includes a steering torque detection unit 26 and a transmission external force adjustment unit 28. The steering torque detection means 26 detects and controls the rotational torque around the steering shaft axis generated in the steering shaft 40 that supports the steering wheel 12 in response to an operation performed by the driver holding the steering wheel 12. Send to system 24. A known torque sensor may be used as the steering torque detecting means.

  The transmission external force adjusting means 28 transmits the power transmission mechanism 20 from the side of the wheel 14 to the steering wheel 12 by an external force acting on the wheel 14 while the vehicle is traveling and acting against the operation of the steering wheel 12. It is a means for adjusting the transmitted external force transmitted. The external force of this wheel will be described later. The transmission external force adjusting means 28 includes, for example, a brake torque applying means that applies a rotational resistance to the steering wheel 12 in a direction against the transmission external force transmitted through the power transmission mechanism 20 described above. As the brake torque applying means, for example, a known brake torque applying mechanism such as a variable damper, an electromagnetic fluid brake, or an electromagnetic brake may be used. Further, rotational torque may be applied to the steering wheel 12 in a direction against the transmission external force transmitted through the power transmission mechanism 20, and in this case, a known means such as an electric motor or actuator may be used. The magnitude of the resistance applied to the steering wheel 12 by the transmission external force adjusting unit 28 is controlled by the control unit 24 based on at least the arm mass information of the driver acquired by the arm mass information acquiring unit 26. For example, when the steering unit and the steering unit are mechanically connected, the brake means 28 may be configured by a known power assist device. Such a power assist device multiplies the steering force received from the steering unit side and transmits it to the wheel 14 side via the power transmission mechanism 20. The external force received by the wheel 14 is also transmitted to the side of the steering unit (finally the steering wheel 12) via the mechanical connection, but is attenuated by the power assist device. In this invention, you may provide both such a power assist apparatus and a brake torque provision means. Further, in the above steer-by-wire system, the reaction force accompanying the turning of the wheel is applied to the steering wheel so that the driver can obtain an appropriate steering feeling. In this case, what is necessary is just to adjust the magnitude | size of the reaction force accompanying the steering of this wheel. The transmission external force adjusting means of the present invention is not particularly limited.

  The steered unit 18 includes steered means 30 and external force detecting means 32. The steering means 30 receives the steering torque transmitted from the steering unit 16 via the power transmission mechanism 20, and steers the wheel 14 in accordance with the steering torque. For example, in a known rack and pinion type steering device, the rotational motion of the main shaft (the motion associated with the rotational motion of the steering wheel 40) is changed to a horizontal motion, and this horizontal motion is further steered. A series of mechanisms such as a steering gear housing and a tie rod that convert into motion correspond to the steering means 30.

  The external force detection means 32 is a means for detecting an external force acting on the wheel 14. The external force referred to here is, for example, a force that the wheel of the vehicle receives from the road surface when passing through the road surface unevenness or a saddle and acts to change the turning amount of the wheel against the operation of the steering wheel 12. I mean. That is, the external force is a force related to the wheel turning that the wheel receives in addition to the steering torque described above. Examples of the external force detection means 32 include a known torque sensor that detects rotational torque in the vicinity of the gear unit of the main shaft, and a displacement sensor that measures horizontal displacement of the tie rod. Information (external force information) related to the external force acquired by the external force detection means is sent to the control means 24.

  The control means 24 receives the information of the steering torque detected by the steering torque detection means 26, the external force information detected by the external force detection means 32, and the arm mass information acquired by the arm mass information acquisition means 22, and includes these information. On the basis of this, by controlling the operation of the transmission external force adjusting means 28, the magnitude of the resistance force applied to the operation of the steering wheel 12 (particularly, the magnitude of the external force received by the wheel transmitted from the wheel 14 side to the steering wheel 12). Is controlled to a predetermined size. As described above, when the driver puts the arm mass on the steering wheel, the moment of the steering wheel (rotational moment about the steering shaft) becomes a moment that takes into account the mass of the arm, and the mass of the arm is heavy. As the steering wheel moment increases. Therefore, when the magnitude of the external force received from the wheel 14 side to the steering wheel 12 is the same, the steering reaction force that the driver feels as the driver's arm mass increases (here, the driver The force on the muscles) And the steering reaction force felt by the driver increases as the driver's arm mass decreases. In the present invention, the magnitude of the transmitted external force transmitted from the wheel side to the steering wheel is set to the magnitude of the driver's arm mass so that the steering feeling felt by the driver is good regardless of the driver. Control is made to a predetermined size set accordingly.

  Here, the arm mass acquisition unit 22 and the arm mass acquisition unit 22 will be described. FIG. 2 is a schematic configuration diagram illustrating an example of arm mass acquisition means. The arm mass acquisition means 22 is provided on a steering shaft 40 that supports the steering wheel 12, and includes a wheel drive unit 42, a torque detection unit 44, an angular velocity detection unit 45, an arm mass calculation unit 46, And control means 48 for controlling the operation. The arm mass acquisition unit 22 includes an instruction information output unit (not shown) connected to the control unit 48 such as a display and a speaker. The instruction information output means (not shown) outputs information instructing the driver's operation in the arm mass information acquisition operation performed by the arm mass information acquisition means 22.

  The wheel drive unit 42 applies torque around the axis to the steering shaft 40 to forcibly drive the steering wheel 12 around the axis of the steering shaft 40. The angular velocity detector 45 measures the angular velocity at this time and sends it to the controller 48. The control unit 48 adjusts the rotational force of the wheel drive unit 42 (that is, adjusts the rotational torque) so that the measured value of the angular velocity becomes a predetermined angular velocity set in advance. Specifically, the control unit 48 causes the angular velocity around the axis of the steering shaft 40 of the steering wheel 12 to be an angular velocity that changes in time series (predetermined angular velocity) that can be represented by a cosine wave shown in FIG. Then, the rotational force of the wheel drive unit 42 is adjusted. At this time, the displacement of the steering wheel 12 around the axis of the steering shaft 40 is a time-series displacement represented by a sine wave as shown in FIG. The torque detector 44 detects the magnitude of the torque around the axis of the steering shaft 40 at this time. As shown in FIG. 3C, the torque detection unit 44 detects the value of the magnitude of time-varying torque (torque around the axis of the steering shaft 40) that varies depending on the magnitude of the arm mass. The Information on the angular velocity of the steering shaft 40 driven by the wheel drive unit 42 under the control of the control unit 48 (information on the predetermined angular velocity) and information on the angular velocity acquired by the torque detection unit 44 are obtained from the arm mass calculation unit 46. Sent to.

  As shown in FIG. 4, the magnitude of the torque around the axis of the steering shaft is proportional to the angular velocity around the axis of the steering shaft, and its inclination changes according to the moment of inertia. The arm mass calculation unit 46 is a state in which the driver holds the steering wheel 12 based on the magnitude and inclination of the torque with respect to the change in the angular velocity when the angular velocity changing in the above time series is given around the axis of the steering shaft 40. The inertia moment (total moment) around the steering shaft axis is obtained. In a state where the driver holds the steering wheel 12 and leaves the weight of the arm to the steering wheel 12, the overall moment is obtained by adding the moment component of the mass of the driver's arm to the moment component of the steering wheel itself. Yes.

  The arm mass information acquisition means 22 stores in advance information on the rotational moment (wheel moment) around the axis of the steering shaft 40 of the steering wheel 12 alone, and the arm mass calculator 46 calculates the calculated total moment of inertia. Therefore, the moment around the axis of the steering shaft 40 (driver moment) of the driver's arm mass is obtained by removing the wheel moment component. Then, the driver's arm mass is calculated from the driver moment and the radius of the steering wheel 12 (that is, the distance between the position where the driver's arm mass is applied to the steering wheel 12 and the axis of the steering wheel 40).

  Such acquisition of arm mass information by the arm mass information acquisition means 22 is performed before the driver starts steering the wheel, preferably immediately after the driver gets into the vehicle. The arm mass information obtained by the arm mass information acquisition unit 22 may be started under the control of the control unit 48 in response to an instruction input from the driver. In addition, a sensor mounted on the vehicle may detect that the driver has entered the vehicle by using a weight sensor or the like, and may start according to the detection information. When the acquisition of the arm mass information by the arm mass information acquisition unit 22 is started, the control unit 48 controls the operation of the instruction information output unit (not shown) so that the driver grips the steering wheel 12 and the arm force Instruct to not remove the arm muscles. In a state where the driver holds the steering wheel 12, the control means 48 rotates the steering wheel by the wheel driving unit 42, and detects the angular velocity at this time by the angular velocity detecting unit 44. Then, the arm mass calculation unit 46 is controlled to calculate the arm mass as described above. At this time, for example, in order to remove the influence of the arm muscle activity, the myoelectric information accompanying the arm muscle activity is measured, and the magnitude of the arm muscle activity is calculated based on this myoelectric information, You may correct | amend the calculation result of arm mass according to the magnitude | size of the calculated muscle activity. The arm mass information acquisition unit 22 acquires the driver's arm mass information in this manner, for example. The obtained arm mass information is sent to the control means 24 as described above.

  FIGS. 5A to 5B are diagrams for explaining the effect of the present invention. Information on the arm masses of the drivers A to D acquired by the above-described arm mass information acquisition unit and each driver are shown in FIGS. It is a figure which shows correlation with the physical feature-value of. FIG. 5A is a scatter diagram showing the correspondence between the weights of the drivers A to D and the arm mass information, and FIG. 5B shows the heights and arm mass information of the drivers A to D. It is a scatter diagram which shows correspondence. FIG. 5C is a scatter diagram showing the correspondence between the muscle strength and arm mass of each of drivers A to D. As shown in FIGS. 5A to 5C, any information on the height of the driver, the weight of the driver, and the muscle strength of the driver has a low correlation with the arm mass. Even if the driver's arm mass is calculated (estimated) based on the driver's physical features, only arm mass information with low accuracy can be obtained. The present invention can directly acquire arm mass information with high accuracy using the arm mass information acquiring means as described above. In the present invention, the arm mass information acquisition means is not limited to the calculation based on the rotation speed of the steering wheel when the torque is applied to the steering shaft and the steering wheel is rotated. For example, the driver is photographed by a camera provided in the vehicle, the driver's arm region is extracted from the photographed image to estimate the driver's arm volume, and the driver is based on the estimated volume. The arm mass information may be calculated as arm mass information. The arm mass information acquisition means of the present invention is not particularly limited.

  The control unit 24 controls the operation of the transmission external force adjusting unit 28 based on the driver's arm mass information acquired in this way, so that the steering characteristics felt by the driver are good regardless of the driver. In addition, the magnitude of the external force received by the wheel transmitted from the wheel side to the steering wheel 12 is controlled. For example, the operation of the transmission external force adjusting means 28 is controlled so that the angular velocity around the axis of the steering wheel 40 of the steering wheel 12 when the wheel is disturbed, and the torque around the axis of the steering wheel 40 is increased. adjust. For example, when the driver's arm mass is small, the operation of the transmission external force adjusting means 12 is controlled so that the torque around the axis of the steering wheel 40 becomes relatively small according to the external force information received by the wheels. When the driver's arm mass is large, the operation of the transmission external force adjusting means 12 is controlled so that the torque around the axis of the steering wheel 40 becomes relatively large according to the external force information received by the wheels. The torque setting value around the axis of the steering wheel 40 set according to the arm mass of the driver is stored in the control means 12 in advance. Further, this set value may be appropriately changed according to the above-described steering torque information and external force information.

Assume that the torque around the axis of the steering wheel 40 is not adjusted by the transmission external force adjusting means 28 according to the external force received by the wheel. For example, in response to external force wheel is subjected, the torque T _S is to have occurred around the axis of the steering wheel 40 (see FIG. 4). In this case, when the driver has a relatively small arm mass, for example, when the total moment is a moment corresponding to the graph shown in FIG. 4A, the driver is driving with the weight of the arm left on the steering wheel 12. , steering wheel 12, to exercise at an angular velocity ω _a. If the steering wheel moves relatively quickly as described above, the steering wheel moves greatly until the driver reacts. Thus, when the steering wheel moves greatly, the behavior of the vehicle becomes unstable. In addition, a driver with a small arm mass is often relatively weak, and it is difficult to control the steering wheel. As a result, the hand holding the steering wheel may be shaken off. Also, for example, when the driver has a relatively large arm mass and the arm moment is B in FIG. 4, and the driver is driving with the weight of the arm left on the steering wheel 12, the steering wheel 12 Exercise at ω _B. Thus, if the steering wheel is moved relatively slowly (just moving slowly), the driver cannot obtain an appropriate sense of disturbance.

For example, when torque T _s is generated around the axis of the steering wheel 40 according to the external force received by the wheel, the driver knows that a suitable steering feeling can be obtained when the steering angular velocity becomes ω _S. And In this case, in the present invention, the torque around the axis of the steering wheel 40 is adjusted by the transmission external force adjusting means 28. For example, in the arm weight is relatively small driver, for example, if the overall moments are moments corresponding to the graph shown in A in FIG. 4, the transmitted external force adjusting means 28, the torque about the axis of the steering wheel 40 T _A Adjust to. By adjusting in this way, a suitable steering feeling can be obtained even for a driver whose overall moment corresponds to the graph shown in FIG. 4A and whose arm mass is relatively small. Further, when the driver has a relatively large arm mass, for example, when the overall moment is a moment corresponding to the graph shown in FIG. 4B, the torque around the axis of the steering wheel 40 is expressed as T _B by the transmission external force adjusting means 28. Adjust to. By adjusting in this way, a suitable steering feeling can be obtained even for a driver whose arm mass corresponds to the graph shown in FIG. 4B and whose arm mass is relatively large. In the present invention, by adjusting the torque around the axis of the steering wheel 40 in accordance with the driver's arm mass, the steering wheel 12 moves at an appropriate angular velocity that can accurately grasp the state of the disturbance, and the driver's The steering wheel can be rotated with an appropriate torque according to the arm mass. In this way, the driver can obtain a good steering feeling regardless of the mass of the driver. In particular, a driver with a small arm mass has an effect of increasing the stability of the vehicle.

  The wheel steering system and the steering reaction force control method of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various improvements and modifications can be made without departing from the scope of the present invention. Of course you can go.

It is a schematic block diagram of an example of the wheel steering system of this invention. It is a schematic block diagram explaining an example of the arm mass information acquisition means of the wheel steering system of this invention. It is a figure explaining an example of operation | movement of the arm mass information acquisition means of the wheel steering system of this invention. It is a graph which shows the relationship between the torque around the axis | shaft of a steering shaft, and angular velocity in the state in which the driver | operator hold | maintained the steering wheel about each of several driver | operators. (A)-(c) is a figure which shows the correlation with the information of each arm mass of driver | operator AD acquired by the arm information acquisition means, and the physical feature-value of each driver | operator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Wheel steering system 12 Steering wheel 14 Wheel 16 Steering unit 18 Steering unit 20 Power transmission mechanism 22 Arm mass information acquisition means 24 Control means 26 Detection means 28 Transmission external force adjustment means 30 Steering means 32 External force detection means 40 Steering shaft 42 Wheel Drive unit 44 Torque detection unit 45 Angular velocity detection unit 46 Arm mass calculation unit 48 Control means

Claims (6)

A wheel steering system for steering a wheel in accordance with an operation of a steering wheel,
An external force transmission means for transmitting the external force received by the wheel acting to steer the wheel against the operation of the steering wheel to the steering wheel;
A wheel steering system comprising: a transmission external force adjusting unit that adjusts a magnitude of a transmission external force transmitted to the steering wheel via the external force transmission unit in accordance with a driver's arm mass information. The external force transmission means includes transmission external force reduction means for reducing the magnitude of the external force received by the wheel and transmitting the reduced force to the steering wheel.
The transmission external force adjustment means adjusts the magnitude of the external force transmitted from the wheel side to the steering wheel by controlling a reduction rate of the external force in the transmission external force reduction means based on the arm mass information. The wheel steering system according to claim 1, wherein:   The wheel steering system according to claim 1, further comprising arm mass information acquisition means for acquiring arm mass information of the driver. The arm mass information acquisition unit includes: a driving unit that drives the steering wheel; a drag measurement unit that measures a resistance against the driving of the steering wheel; and an arm that calculates the arm mass information based on the measured resistance A mass calculating means; and a control means for controlling operations of the driving means, the drag measuring means, and the arm mass calculating means,
The control means causes the driving means to drive the steering wheel in a state where the driver grips the steering wheel and the arm weight of the driver is applied to the steering wheel. The wheel steering system according to claim 3, wherein a force is measured by the drag measuring unit, and the arm mass calculating unit is configured to calculate the arm mass information based on the measured resistance force. The steering wheel and the wheel are mechanically connected via the external force transmission means,
And a power assist device that receives the operation of the steering wheel, and multiplies the operation force to transmit to the wheel side,
The transmission external force adjusting means adjusts the magnitude of the external force transmitted from the wheel side to the steering wheel by controlling a multiplication factor of the operation force in the power assist device based on the arm mass information. The wheel steering system according to any one of claims 1 to 4. A method of controlling the magnitude of a steering reaction force received by the driver from the steering wheel in wheel steering in which the driver grips the steering wheel and operates the rotation of the steering wheel to steer the wheel. ,
An operation reaction force control method, comprising: controlling a magnitude of a disturbance-induced reaction force acting on the steering wheel according to an external force received by the wheel based on arm mass information of the driver.

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