JP7342414B2 - Steering control device - Google Patents

Description

The present invention relates to a steering control device.

2. Description of the Related Art Conventionally, there has been an EPS (electric power steering system) that applies torque from a motor as assist force to a steering mechanism of a vehicle. For example, the EPS control device described in Patent Document 1 switches the motor control method between a torque control method and a rotation angle control method according to a predetermined switching trigger. The torque control method refers to a control method for controlling the output torque of the motor. The rotation angle control method refers to a control method for controlling the rotation angle of the motor.

For example, when switching its operating mode from manual steering mode to automatic steering mode, the control device switches the motor control method from the torque control method to the rotation angle control method. This is because the driver basically does not steer the steering wheel when automatic steering is performed. Further, when switching its own operation mode from automatic steering mode to manual steering mode, the control device switches the motor control method from the rotation angle control method to the torque control method.

When switching its operating mode from automatic steering mode to manual steering mode, the control device directs the current command value for the motor from a first command value based on the rotation angle control method to a second command value based on the torque control method. change gradually. Thereby, when the operation mode of the control device is switched from automatic steering mode to manual steering mode, a sudden change in the current command value for the motor is suppressed.

Japanese Patent Application Publication No. 2004-17881

The control device of Patent Document 1 basically sets a first command value based on a rotation angle control method and a second command value based on a torque control method as a command value for the current to be supplied to the motor, depending on its own operation mode. Use one of the command values. Therefore, the motor torque applied to the steering mechanism is also based on either the first command value or the second command value.

In recent years, there has been a need to respond to globally diversifying needs. EPS control devices are also required to respond flexibly to changes in product specifications or future specifications. Therefore, the EPS control device is required to have more room to adjust the motor torque, for example, in order to generate a more appropriate assist force according to the product specifications.

Note that a control device for a so-called steer-by-wire steering device in which power transmission between the steering wheel and steered wheels is separated also has the same problem as the EPS control device.
An object of the present invention is to provide a steering control device that can apply more appropriate driving force to a steering mechanism.

A steering control device capable of achieving the above object includes a control unit that controls a motor, which is a source of a driving force applied to a steering mechanism of a vehicle, based on a command value calculated according to a steering state. The control unit includes a first calculation unit that calculates a first command value that is reflected in the command value depending on a steering state, and a second calculation unit that calculates a second command value that is reflected in the command value depending on the steering state. a second calculation section that calculates a first distribution ratio for the first command value and a second distribution ratio for the second command value in response to an external command instructing a steering state of the vehicle; 3, the calculation unit calculates the command value by adding together the value obtained by multiplying the first command value by the first distribution ratio and the value obtained by multiplying the second command value by the second distribution ratio. and a fourth calculation unit that calculates. The first calculation unit calculates the first command value through feedback control of steering torque detected through a first sensor mounted on the vehicle. The second calculation unit calculates the second command value through feedback control of a steering angle detected through a second sensor mounted on the vehicle.

According to this configuration, the proportion of the first command value and the second command value in the command value is changed according to the first distribution ratio and the second distribution ratio calculated by the third calculation unit. Is possible. If the ratio of the first command value and the second command value to the command value changes, the command value based on the first command value and the second command value also changes. Therefore, there is more room to adjust the torque of the motor depending on the steering state of the vehicle. Furthermore, depending on the settings of the first distribution ratio and the second distribution ratio, it is possible to apply a more appropriate driving force to the steering mechanism of the vehicle.

In the above steering control device, when the value of the first distribution ratio calculated by the third calculation unit is changed, the first distribution ratio before the change is changed from the first distribution ratio after the change. When the value of the second distribution ratio calculated by the first gradual change processing unit and the third calculation unit is changed, the value of the second distribution ratio is changed from the second distribution ratio before the change. It is preferable to include a second gradual change processing section that gradually changes the distribution ratio toward the changed second distribution ratio.

According to this configuration, when the first distribution ratio and the second distribution ratio are changed, sudden changes in the command value can be suppressed. The discomfort caused by sudden changes in command values can be suppressed.
In the above steering control device, the control unit is configured to execute steering control based on a distribution command generated when a higher-level control device mounted on the vehicle intervenes in steering control, and the external command is configured to May include instructions.

The requirements for the driving force generated by the motor may differ depending on whether or not the higher-level control device intervenes in steering control. In this regard, according to the above configuration, the distribution ratios of the first command value and the second command value are respectively set based on the distribution command generated by the host controller, so that the host controller controls the steering control. The final values of the first command value and the second command value reflected in the command value change depending on whether or not to intervene. That is, when the host control device intervenes in steering control, the driving force generated by the motor is changed according to the distribution command. Therefore, it is possible to appropriately respond to intervention in steering control by the host control device.

The above-mentioned steering control device may include an abnormality detection section that detects abnormality of the first sensor and the second sensor. In this case, the external command may include an abnormality detection signal generated by the abnormality detection section.

The demand for the driving force generated by the motor may be different depending on whether or not an abnormality occurs in the first sensor or the second sensor. In this regard, according to the above configuration, the distribution ratios of the first command value and the second command value are respectively set based on the abnormality detection signal generated by the abnormality detection section. The final values of the first command value and the second command value reflected in the command value change depending on whether an abnormality occurs in the second sensor or not. That is, when an abnormality occurs in the first sensor or the second sensor, the driving force generated by the motor is changed according to the distribution ratio. Therefore, it is possible to appropriately respond to abnormalities in the first sensor or the second sensor.

In the above-described steering control device, when an abnormality in either the first sensor or the second sensor is detected through the abnormality detection unit, the third calculation unit is configured to detect the abnormality in the sensor in which the abnormality has been detected. While reducing the distribution ratio for either the first command value or the second command value obtained through use, the first command value or the second command value obtained through the use of a sensor in which no abnormality is detected is reduced. It is preferable to increase the allocation ratio of one command value to the other.

According to this configuration, the degree to which the first command value or the second command value obtained through the use of the sensor in which the abnormality has been detected is reflected in the final command value is reduced. Therefore, the influence of sensor abnormality on the motor torque can be reduced. Furthermore, although one of the first command value and the second command value obtained through the use of the sensor in which the abnormality has been detected decreases, the first command value and the second command value obtained through the use of the sensor in which the abnormality is not detected are decreased. The other of the two command values increases. Therefore, a significant decrease in the total command value, that is, the torque generated by the motor as a whole, is suppressed.

In the above-mentioned steering control device, on the premise that the motor has a plurality of winding groups, the number of control units is the same as the number of systems that independently control the power supply to the plurality of winding groups for each system. , and an abnormality detection unit that independently detects abnormalities in a plurality of power supply systems including the control unit for each system. In this case, the external command may include an abnormality detection signal generated by the abnormality detection section.

The requirements for the driving force generated by the winding groups of each power supply system may be different depending on whether or not an abnormality occurs in one of the plurality of power supply systems. In this regard, according to the above configuration, the distribution ratio of the first command value and the second command value is set in each of the control parts of the same number as the number of systems based on the abnormality detection signal generated by the abnormality detection part. be done. As a result, the final first command value and the final command value to be reflected in the command value for each of the winding groups of the multiple power supply systems, depending on whether or not an abnormality occurs in one of the multiple power supply systems. The value of command value 2 changes. That is, when an abnormality occurs in any one of the plurality of power supply systems, the driving force generated by the motor is changed according to the distribution command. Therefore, it is possible to appropriately respond to an abnormality in any one of the plurality of power supply systems.

In the above steering control device, when an abnormality in any one of the plurality of power supply systems is detected through the abnormality detection unit, the control unit of the abnormality system detects a winding group of the own system that is abnormal. While decreasing the allocation ratios for the first command value and the second command value to be reflected in the command value for the normal system, the control unit of the normal system reduces the command value for the winding group of the self system that is normal. It is preferable to respectively increase the distribution ratios for the first command value and the second command value that are reflected in the first command value and the second command value.

According to this configuration, the command value for the winding group of the abnormal system is reduced. Therefore, the influence of an abnormality occurring in the abnormal system on the torque of the motor can be reduced. Further, although the command value for the winding group of the abnormal system decreases, the command value for the winding group of the normal system increases. Therefore, a significant decrease in the torque generated by the motor as a whole is suppressed.

In the above steering control device, the steering mechanism includes a steering shaft that rotates in conjunction with the operation of a steering wheel and has separate power transmission from the steered wheels, and the motor is attached to the steering shaft. The driving force may be a reaction force motor that generates a steering reaction force that is a torque in a direction opposite to the steering direction.

In the above steering control device, the steering mechanism includes a shaft that rotates in conjunction with the operation of a steering wheel, and a steering shaft that steers steered wheels in conjunction with the rotation of the shaft, and the motor is configured to rotate the shaft. Alternatively, the driving force applied to the steered shaft may be an assist motor that generates a steering assist force that is a torque in the same direction as the steering direction.

According to the steering control device of the present invention, more appropriate driving force can be applied to the steering mechanism.

FIG. 1 is a configuration diagram of a steer-by-wire steering device in which a first embodiment of a steering control device is installed. FIG. 1 is a control block diagram of a first embodiment of a steering control device. FIG. 3 is a control block diagram of a steering reaction force command value calculation section in the first embodiment. FIG. 3 is a control block diagram showing a first comparative example of an arbitration processing unit. FIG. 7 is a control block diagram showing a second comparative example of an arbitration processing unit. FIG. 2 is a control block diagram showing a peripheral configuration of an arbitration processing unit in the first embodiment. FIG. 7 is a control block diagram showing a peripheral configuration of an arbitration processing section in a second embodiment of the steering control device. FIG. 7 is a control block diagram showing a peripheral configuration of an arbitration processing section in a third embodiment of the steering control device. FIG. 7 is a control block diagram of a fourth embodiment of the steering control device. FIG. 7 is a control block diagram showing a peripheral configuration of an arbitration processing unit in a fourth embodiment. FIG. 7 is a control block diagram of a steering reaction force command value calculating section in a fifth embodiment of the steering control device. FIG. 7 is a control block diagram of a sixth embodiment of a steering control device installed in an electric power steering device.

<First embodiment>
A first embodiment in which a steering control device is applied to a steer-by-wire steering device will be described below.

As shown in FIG. 1, a vehicle steering system 10 includes a steering shaft 12 connected to a steering wheel 11. As shown in FIG. The steering shaft 12 constitutes a steering mechanism. The steering device 10 also includes a steering shaft 14 that extends along the vehicle width direction (the left-right direction in FIG. 1). Left and right steered wheels 16, 16 are connected to both ends of the steered shaft 14 via tie rods 15, 15, respectively. By linearly moving the steered shaft 14, the steered angle θ _w of the steered wheels 16, 16 is changed.

<Configuration for generating steering reaction force: reaction force unit>
Further, the steering device 10 includes a reaction force motor 31, a deceleration mechanism 32, a rotation angle sensor 33, and a torque sensor 34 as components for generating a steering reaction force. Incidentally, the steering reaction force refers to a force (torque) that acts in a direction opposite to the direction in which the steering wheel 11 is operated by the driver. By applying a steering reaction force to the steering wheel 11, it is possible to give the driver an appropriate feeling of response.

The reaction force motor 31 is a source of steering reaction force. As the reaction motor 31, for example, a three-phase (U, V, W) brushless motor is employed. The reaction motor 31 (more precisely, its rotating shaft) is connected to the steering shaft 12 via a speed reduction mechanism 32 . The torque of the reaction force motor 31 is applied to the steering shaft 12 as a steering reaction force.

The rotation angle sensor 33 is provided on the reaction force motor 31. The rotation angle sensor 33 detects the rotation angle _θa of the reaction force motor 31. The rotation angle θ _a of the reaction motor 31 is used to calculate the steering angle (steering angle) θ _s . The reaction motor 31 and the steering shaft 12 are interlocked via a speed reduction mechanism 32. Therefore, there is a correlation between the rotation angle θ _a of the reaction motor 31 and the rotation angle of the steering shaft 12 , and furthermore, the steering angle θ _s which is the rotation angle of the steering wheel 11 . Therefore, the steering angle θ _s can be determined based on the rotation angle θ _a of the reaction motor 31.

The torque sensor 34 detects the steering torque T _h applied to the steering shaft 12 through a rotational operation of the steering wheel 11 . The torque sensor 34 is provided in a portion of the steering shaft 12 closer to the steering wheel 11 than the speed reduction mechanism 32 is.

<Configuration for generating steering force: steering unit>
Further, the steering device 10 includes a steering motor 41, a deceleration mechanism 42, and a rotation angle sensor 43 as a configuration for generating steering force that is power for steering the steered wheels 16, 16. There is.

The steering motor 41 is a source of steering force. As the steering motor 41, for example, a three-phase brushless motor is employed. The steering motor 41 (more precisely, its rotating shaft) is connected to a pinion shaft 44 via a speed reduction mechanism 42 . The pinion teeth 44a of the pinion shaft 44 are engaged with the rack teeth 14b of the steered shaft 14. The torque of the steering motor 41 is applied to the steering shaft 14 via the pinion shaft 44 as a steering force. In accordance with the rotation of the steering motor 41, the steering shaft 14 moves along the vehicle width direction (left-right direction in the figure).

The rotation angle sensor 43 is provided on the steering motor 41. The rotation angle sensor 43 detects the rotation angle θ _b of the steering motor 41 .
Incidentally, the steering device 10 has a pinion shaft 13. The pinion shaft 13 is provided so as to intersect with the steered shaft 14. The pinion teeth 13a of the pinion shaft 13 are engaged with the rack teeth 14a of the steered shaft 14. The reason for providing the pinion shaft 13 is to support the steering shaft 14 together with the pinion shaft 44 inside a housing (not shown). That is, the steering shaft 14 is supported movably along its axial direction by a support mechanism (not shown) provided in the steering device 10 and is pressed toward the pinion shafts 13 and 44 . Thereby, the steered shaft 14 is supported inside the housing. However, other support mechanisms may be provided to support the steered shaft 14 in the housing without using the pinion shaft 13.

<Control device>
Further, the steering device 10 includes a control device 50. The control device 50 controls the reaction motor 31 and the steering motor 41 based on the detection results of various sensors. In addition to the aforementioned rotation angle sensor 33, torque sensor 34, and rotation angle sensor 43, the sensors include a vehicle speed sensor 501. Vehicle speed sensor 501 is provided in a vehicle and detects vehicle speed V, which is the traveling speed of the vehicle.

The control device 50 executes reaction force control to generate a steering reaction force according to the steering torque _Th through drive control of the reaction force motor 31. The control device 50 calculates a target steering reaction force based on the steering torque _Th and the vehicle speed V, and calculates a target steering angle of the steering wheel 11 based on the calculated target steering reaction force, the steering torque _Th , and the vehicle speed V. The control device 50 calculates a steering angle correction amount through feedback control of the steering angle θ _s that is executed to make the actual steering angle θ _s follow the target steering angle, and sets the calculated steering angle correction amount to the target steering angle. The steering reaction force command value is calculated by adding it to the force. The control device 50 supplies the reaction force motor 31 with the current required to generate a steering reaction force according to the steering reaction force command value.

The control device 50 performs steering control to steer the steered wheels 16, 16 according to the steering state through drive control of the steered motor 41. The control device 50 calculates the pinion angle θ _p , which is the actual rotation angle of the pinion shaft 44, based on the rotation angle θ _b of the steering motor 41 detected through the rotation angle sensor 43. This pinion angle θ _p is a value that reflects the steered angle θ _w of the steered wheels 16 , 16 . The control device 50 calculates a target pinion angle using the target steering angle described above. Then, the control device 50 determines the deviation between the target pinion angle and the actual pinion angle θ _p , and controls the power supply to the steering motor 41 so as to eliminate the deviation.

Here, the vehicle is equipped with a driving support system that supports the driver's driving operations in order to achieve safe and better driving, or an automated driving system that realizes an automated driving function where the system replaces driving. There is. In this case, in the vehicle, cooperative control is performed between the control device 50 and the control devices of other in-vehicle systems. Cooperative control refers to a technology in which control devices of multiple types of in-vehicle systems cooperate with each other to control the movement of a vehicle. The vehicle is equipped with, for example, a host control device 500 that centrally controls control devices of various in-vehicle systems. The host control device 500 determines an optimal control method based on the current state of the vehicle, and issues individual control instructions to various vehicle-mounted control devices according to the desired control method.

The higher-level control device 500 intervenes in the steering control by the control device 50. The host control device 500 switches its own driving support control function or automatic driving control function between on (valid) and off (invalid) through the operation of a switch (not shown) provided on the driver's seat or the like.

The host control device 500 calculates an additional angle command value, for example, as a command value S ^* for causing the vehicle to travel on the target lane. The additional angle command value is a target value of the steering angle (an angle to be added to the current steering angle) required to drive the vehicle along the lane, depending on the current driving state of the vehicle. The control device 50 controls the reaction motor 31 and the steering motor 41 using the command value S ^* calculated by the host control device 500.

Further, the host control device 500 generates a flag as a distribution command S _r for the control device 50 . The flag is information indicating whether the driving support control function or the automatic driving control function is on or off. The upper control device 500 sets the value of the flag to "1" when the driving support control function or the automatic driving control function is on, and sets the value of the flag to "0" when the driving support control function or the automatic driving control function is off. Set to . Note that the distribution command S _r corresponds to an external command that instructs the steering state of the vehicle.

<Detailed configuration of control device>
Next, the control device 50 will be explained in detail.
As shown in FIG. 2, the control device 50 includes a reaction force control section 50a that performs reaction force control, and a steering control section 50b that performs steering control.

<Reaction force control section>
The reaction force control section 50a includes a steering angle calculation section 51, a steering reaction force command value calculation section 52, and an energization control section 53.

The steering angle calculating section 51 calculates the steering angle _{θ s} of the steering wheel 11 based on the rotation angle _{θ a} of the reaction force motor 31 detected through the rotation angle sensor 33 .
The steering reaction force command value calculating section 52 calculates the steering reaction force command value T ^* based on the steering torque T _h , the vehicle speed V, and the steering angle θ _s . The steering reaction force command value calculating section 52 calculates a steering reaction force command value T ^* having a larger absolute value as the absolute value of the steering torque T _h is larger and as the vehicle speed V is lower. Incidentally, the steering reaction force command value calculation unit 52 calculates the target steering angle θ ^* of the steering wheel 11 in the process of calculating the steering reaction force command value T ^* . The steering reaction force command value calculation unit 52 will be described in detail later.

The energization control unit 53 supplies the reaction force motor 31 with electric power according to the steering reaction force command value T ^* . Specifically, the energization control unit 53 calculates a current command value for the reaction force motor 31 based on the steering reaction force command value T ^* . Further, the energization control unit 53 detects, through a current sensor 54 provided in the power supply path to the reaction force motor 31, the actual current value _Ia generated in the power supply path. This current value _Ia is the actual value of the current supplied to the reaction force motor 31. Then, the energization control unit 53 determines the deviation between the current command value and the actual current value _Ia , and controls the power supply to the reaction force motor 31 so as to eliminate the deviation (feedback control of the current _Ia ). Thereby, the reaction force motor 31 generates torque according to the steering reaction force command value T ^* . It is possible to provide the driver with an appropriate feeling of response depending on the road reaction force.

<Steering control section>
The steering control section 50b includes a pinion angle calculation section 61, a pinion angle feedback control section 62, and an energization control section 63.

The pinion angle calculating section 61 calculates a pinion angle θ _p which is the actual rotation angle of the pinion shaft 44 based on the rotation angle θ _b of the steering motor 41 detected through the rotation angle sensor 43 . The steering motor 41 and pinion shaft 44 are interlocked via a speed reduction mechanism 42 . Therefore, there is a correlation between the rotation angle θ _b of the steering motor 41 and the pinion angle θ _p . Using this correlation, the pinion angle θ _p can be determined from the rotation angle θ _b of the steering motor 41. Further, the pinion shaft 44 is meshed with the steered shaft 14. Therefore, there is also a correlation between the pinion angle θ _p and the amount of movement of the steered shaft 14 . That is, the pinion angle θ _p is a value that reflects the steered angle θ _w of the steered wheels 16 , 16 .

The pinion angle feedback control unit 62 takes in the target steering angle θ ^* calculated by the steering reaction force command value calculation unit 52 as the target pinion angle θ _p ^* . Further, the pinion angle feedback control section 62 takes in the actual pinion angle θ _p calculated by the pinion angle calculation section 61. The pinion angle feedback control unit 62 performs feedback control (PID control) _of the pinion angle θ _p in order to make the actual pinion angle θ p follow the target pinion angle θ _p ^* (here, equal to the target steering angle θ ^* ). A pinion angle command value T _p ^* is calculated.

The energization control unit 63 supplies power to the steering motor 41 according to the pinion angle command value T _p ^* . Specifically, the energization control unit 63 calculates a current command value for the steering motor 41 based on the pinion angle command value T _p ^* . Further, the energization control unit 63 detects, through a current sensor 64 provided in the power supply path to the steering motor 41, an actual current value _Ib generated in the power supply path. This current value _Ib is the actual value of the current supplied to the steering motor 41. Then, the energization control unit 63 determines the deviation between the current command value and the actual current value _Ib , and controls the power supply to the steering motor 41 so as to eliminate the deviation (feedback control of the current value _Ib ). As a result, the steering motor 41 rotates by an angle corresponding to the pinion angle command value T _p ^* .

<Steering reaction force command value calculation section>
Next, the steering reaction force command value calculation section 52 will be explained in detail.
As shown in FIG. 3, the steering reaction force command value calculation unit 52 includes an adder 70, a target steering torque calculation unit 71, a torque feedback control unit 72, an axial force calculation unit 73, a target steering angle calculation unit 74, a steering angle feedback It has a control section 75 and an arbitration processing section 76.

The adder 70 adds the steering torque T _h detected through the torque sensor 34 and the first steering reaction force command value T ₁ ^* calculated by the torque feedback control unit 72 to calculate the amount of torque that is applied to the steering shaft 12 . The input torque T _in ^* as the torque to be calculated is calculated.

The target steering torque calculating section 71 calculates a target steering torque T _h ^* based on the input torque T _in ^* calculated by the adder 70 . The target steering torque T _h ^* refers to the target value of the steering torque T _h to be applied to the steering wheel 11. The target steering torque calculation unit 71 calculates a target steering torque T _h ^* having a larger absolute value as the absolute value of the input torque T _{in *} becomes larger ^.

The torque feedback control unit 72 takes in the steering torque T _h detected through the torque sensor 34 and the target steering torque T _h ^* calculated by the target steering torque calculation unit 71. The torque feedback control unit 72 controls the first steering reaction force command value T through feedback control (PID control) of the steering torque T _h so that the steering torque T _h detected through the torque sensor 34 follows the target steering torque T _h ^* . ₁ ^* is calculated.

The axial force calculation unit 73 takes in the target steering angle θ ^* calculated by the target steering angle calculation unit 74 as the target pinion angle θ _p ^* . The axial force calculation unit 73 also takes in the current value I _b of the steering motor 41 detected through the current sensor 64 and the vehicle speed V detected through the vehicle speed sensor 501. The axial force calculation unit 73 calculates the axial force F _ax that acts on the steered shaft 14 through the steered wheels 16 and 16 based on the target pinion angle θ _p ^* , the current value I _b of the steered motor 41, and the vehicle speed V. . Specifically, it is as follows.

The axial force calculation unit 73 calculates an ideal axial force, which is an ideal value of the axial force acting on the steered shaft 14 through the steered wheels 16, 16, based on the target pinion angle θ _p ^* . The axial force calculation unit 73 calculates the ideal axial force using an ideal axial force map stored in a storage device (not shown) of the control device 50. The ideal axial force increases as the absolute value of the target pinion angle θ _p ^* (or the target steering angle obtained by multiplying the target pinion angle θ _p ^* by a predetermined conversion coefficient) increases, and as the vehicle speed V decreases. , set to a larger absolute value. Note that the vehicle speed V does not necessarily have to be taken into consideration.

Further, the axial force calculation unit 73 calculates the estimated axial force acting on the steered shaft 14 based on the current value _Ib of the steered motor 41. Here, the current value _Ib of the steered motor 41 is determined by the difference between the target pinion angle θ _p ^* and the actual pinion angle θ _p due to the fact that a disturbance according to the road surface condition (road surface frictional resistance) acts on the steered wheels 16. It changes depending on the difference between the two. That is, the current value Ib of the steered motor 41 reflects the actual road surface reaction force acting on the steered wheels 16, 16. Therefore, it is possible to calculate the axial force that reflects the influence of the road surface condition based on the current value _Ib of the steering motor 41. The estimated axial force is obtained by multiplying the current value Ib of the steering motor 41 by a gain that is a coefficient according to the vehicle speed V.

Then, the axial force calculation unit 73 individually sets a distribution ratio (gain) for the ideal axial force and a distribution ratio for the estimated axial force. The axial force calculation unit 73 calculates the axial force F _ax by summing values obtained by multiplying the ideal axial force and the estimated axial force by distribution ratios set individually. The distribution ratio is set according to various state variables that reflect vehicle behavior, road surface conditions, or steering conditions.

The target steering angle calculation unit 74 calculates the steering torque T _h detected through the torque sensor 34, the first steering reaction force command value T ₁ ^* calculated by the torque feedback control unit 72, and the axial force calculation unit 73. The axial force F _ax and the vehicle speed V detected through the vehicle speed sensor 501 are taken in. The target steering angle calculation unit 74 calculates the target steering angle θ ^* of the steering wheel 11 based on the incorporated steering torque T _h , first steering reaction force command value T ₁ ^* , axial force F _ax , and vehicle speed V. . Specifically, it is as follows.

The target steering angle calculation unit 74 converts the axial force F _ax into torque from the input torque T _in ^* which is the sum of the first steering reaction force command value T ₁ ^* and the steering torque _Th . By subtracting the corresponding steering reaction force), the final input torque T _in ^* to the steering wheel 11 is determined. The target steering angle calculating section 74 calculates a target steering angle θ ^* (target steering angle) from the final input torque T _in ^* based on an ideal model expressed by the following equation (A). This ideal model assumes a steering device in which the steering wheel 11 and the steered wheels 16, 16 are mechanically connected, and the steering wheel corresponds to the ideal steered angle according to the input torque T _in ^*. 11 are modeled in advance through experiments and the like.

T _in ^* =Jθ ^*′′ +Cθ ^*′ +Kθ ^* …(A)
However, "J" is the inertia coefficient corresponding to the moment of inertia of the steering wheel 11 and the steering shaft 12, "C" is the viscosity coefficient (friction coefficient) corresponding to the friction of the steering shaft 14 against the housing, and "K" is the steering This is a spring coefficient when the wheel 11 and the steering shaft 12 are each considered as a spring. The viscosity coefficient C and the inertia coefficient J have values according to the vehicle speed V. Further, "θ ^*'' " is the second-order time differential value of the target steering angle θ ^* , and "θ ^* '" is the first-order time differential value of the target steering angle θ ^* .

Incidentally, when the additional angle command value is calculated as the command value S ^* through execution of driving support control or automatic driving control by the host controller 500, the command value S ^* is the target rudder angle calculated by the target rudder angle calculation unit 74. is added to the angle θ ^* . The final target steering angle θ ^* to which this command value S ^* is added is supplied to the axial force calculation section 73 and the steering angle feedback control section 75, respectively.

The steering angle feedback control unit 75 takes in the steering angle θ _s calculated by the steering angle calculation unit 51 and the target steering angle θ ^* calculated by the target steering angle calculation unit 74 . The steering angle feedback control unit 75 sets a second steering reaction force command value T through feedback control of the steering angle θ _s in order to cause the actual steering angle θ _s calculated by the steering angle calculation unit 51 to follow the target steering angle θ ^* . ₂ ^* is calculated.

The arbitration processing unit 76 adjusts the first steering reaction force command value T ₁ ^* calculated by the torque feedback control unit 72 and the second steering reaction force command value T ₂ ^* calculated by the steering angle feedback control unit 75. Based on this, a steering reaction force command value T ^* is calculated.

<Comparison example of arbitration processing unit>
The arbitration processing unit 76 may have various configurations depending on product specifications, etc., and here, two configurations will be first described as comparative examples.

As shown in FIG. 4, the first comparative example of the arbitration processing unit 76 includes a switch 81. The switch 81 receives a first steering reaction force command value T ₁ ^* calculated by the torque feedback control unit 72 and a second steering reaction force command value T ₂ calculated by the steering angle feedback control unit 75 as data inputs. Incorporate ^* . Further, the switch 81 takes in a flag as a distribution command S _r generated by the host control device 500 as a control input. The switch 81 controls the final steering reaction to supply either the first steering reaction force command value T ₁ ^* or the second steering reaction force command value T ₂ ^* to the energization control section 53 based on the value of the flag. Set as force command value T ^* . When the value of the flag as the distribution command S _r is "0", the switch 81 converts the first steering reaction force command value T ₁ ^* calculated by the torque feedback control unit 72 into the final steering reaction force command value. It is supplied to the energization control section 53 as T ^* . When the value of the flag as the distribution command S _r is “1” (more precisely, when the value of the flag is not “0”), the switch 81 is activated to control the second The steering reaction force command value T ₂ ^* is supplied to the energization control unit 53 as the final steering reaction force command value T ^* .

As shown in FIG. 5, the second comparative example of the arbitration processing section 76 includes a switch 82 and an adder 83. The switch 82 takes in the second steering reaction force command value T ₂ ^* calculated by the steering angle feedback control unit 75 and a fixed value “0” stored in a storage device (not shown) as data input. Further, the switch 82 takes in a flag as a distribution command S _r generated by the host control device 500 as a control input. The switch 82 selects either the second steering reaction force command value T ₂ ^* or the fixed value "0" based on the value of the flag. The switch 82 selects the fixed value "0" when the value of the flag as the distribution command _Sr is "0". When the value of the flag as the distribution command S _r is “1” (more precisely, when the value of the flag is not “0”), the switch 82 is activated to control the second The steering reaction force command value T ₂ ^* is selected. The adder 83 outputs a first steering reaction force command value T ₁ ^* calculated by the torque feedback control unit 72 and a fixed value “0” selected by the switch 82 or a second steering reaction force command value T ₂ ^* . The final steering reaction force command value T ^* is calculated by adding .

Thus, according to the first comparative example of the arbitration processing unit 76, the first steering reaction force command value T 1 ^* calculated by the torque feedback control unit 72 is used as the final steering reaction force command value T _* ^. , and the second steering reaction force command value T ₂ ^* calculated by the steering angle feedback control unit 75. Further, according to the second comparative example of the arbitration processing unit 76, only the first steering reaction force command value T 1 * is used as the final steering reaction force command value T ^* , or the first steering reaction force command value T ₁ ^* is used as the final steering reaction force command value T *. A value that is simply the sum of the reaction force command value T ₁ ^* and the second steering reaction force command value T ₂ ^* is used. That is, the torque generated by the reaction force motor 31 is equal to at least the first steering reaction force command value T ₁ ^* of the first steering reaction force command value T ₁ ^* and the second steering reaction force command value T ₂ ^* . It will be based on.

However, in recent years, in order to flexibly respond to product specifications or future specification changes, the control device 50 has been equipped with a control device that, for example, adjusts the torque of the reaction force motor 31 in order to generate a more appropriate steering reaction force according to the product specifications. It is necessary to expand the scope for Therefore, in this embodiment, the following configuration is adopted as the control device 50.

<Arbitration processing unit>
As shown in FIG. 6, the steering reaction force command value calculation unit 52 of the control device 50 includes a control manager 91. The control manager 91 takes in the flag as the distribution command _Sr generated by the higher-level control device 500. The control manager 91 calculates two distribution ratios DR _m and DR _a based on the value of the flag as the distribution command S _r and according to multiple types of state variables that reflect vehicle behavior, road surface conditions, or steering conditions. . The distribution ratio DR _m is for the first steering reaction force command value T ₁ ^* calculated by the torque feedback control unit 72 . The distribution ratio DR _a is for the second steering reaction force command value T ₂ ^* calculated by the steering angle feedback control unit 75.

The control manager 91 can set the values of the two distribution ratios DR _m and DR _a in the range of "0" to "1", for example, in increments of "0.1" based on product specifications and the like. However, the control manager 91 sets the two distribution ratios DR _m and DR _a such that the sum of the two distribution ratios DR _m and DR _a becomes "1". Incidentally, state variables include, for example, yaw rate, lateral acceleration, steering angle θ _s , pinion angle θ _p , vehicle speed V, steering speed, pinion angular velocity, and the like. The steering speed is obtained by differentiating the steering angle θ _s . The pinion angular velocity is obtained by differentiating the pinion angle θ _p .

Further, the arbitration processing section 76 includes two multipliers 92 and 93 and an adder 94.
The multiplier 92 multiplies the first steering reaction force command value T ₁ ^* calculated by the torque feedback control unit 72 by the distribution ratio DR _m calculated by the control manager 91 to obtain the distribution ratio DR _m . A corresponding first steering reaction force command value T _1m ^* is calculated. The distribution ratio DR _m is set each time according to a state quantity that reflects vehicle behavior, road surface condition, or steering condition.

The multiplier 93 multiplies the second steering reaction force command value T ₂ ^* calculated by the steering angle feedback control unit 75 by the distribution ratio DR _a calculated by the control manager 91, thereby determining the distribution ratio DR _a. A second steering reaction force command value T _2a ^* corresponding to is calculated. The distribution ratio _DRa is set each time according to a state quantity that reflects vehicle behavior, road surface condition, or steering condition.

The adder 94 adds the first steering reaction force command value T _1m ^* calculated by the multiplier 92 and the second steering reaction force command value T _2a ^* calculated by the multiplier 93. A final steering reaction force command value T ^* is calculated.

<Operation of the first embodiment>
Next, the operation of the first embodiment will be explained.
As described above, the control manager 91 can appropriately set the values of the two distribution ratios DR _m and DR _a in the range of "0" to "1" in increments of "0.1". Therefore, during automatic operation and manual operation, the first steering reaction force that accounts for the final steering reaction force command value T ^* is determined by the values of the two distribution ratios DR _m and DR _a calculated by the control manager 91. The ratio of the command value T ₁ ^* and the second steering reaction force command value T ₂ ^* is set, for example, from "T ₁ ^* : T ₂ ^* = 100%: 0%" to "T ₁ ^* : T ₂ ^* = 0%: It can be freely changed within the range of 100%.

For example, when driving support or automatic driving is performed, that is, when the value of the flag as the distribution command S _r is "1", the control manager 91 sets the value of the distribution ratio DR a to "_1" according to the product specifications etc. 0.5 (50%)", and the value of the distribution ratio DR _m may be set to "0.5 (50%)". In this case, the proportions of the first steering reaction force command value T ₁ ^* and the second steering reaction force command value T ₂ ^* in the final steering reaction force ^command value T * are each 50%.

Further, when the value of the flag as the distribution command S _r is "1", the control manager 91 sets the value of the distribution ratio DR _a to "0.7 (70%)" and the distribution ratio DR according to the product specifications. The value of _m may be set to "0.3 (30%)". In this case, the ratio of the second steering reaction force command value T ₂ ^* to the final steering reaction force command value T ^* is 70%, and the ratio of the first steering reaction force command value T ₁ ^* is 30%. .

Further, when the value of the flag as the distribution command S _r is "1", the control manager 91 sets the value of the distribution ratio DR _a to "0.3 (30%)" and the distribution ratio DR according to the product specifications, etc. The value of _m may be set to "0.7 (70%)". In this case, the ratio of the second steering reaction force command value T ₂ ^* to the final steering reaction force command value T ^* is 30%, and the ratio of the first steering reaction force command value T ₁ ^* is 70%. .

Further, when the value of the flag as the distribution command S _r is "1", the control manager 91 sets the value of the distribution ratio DR _{a to} "1" and the value of the distribution ratio DR _m to "0" according to the product specifications etc. ”. In this case, the ratio of the second steering reaction force command value T ₂ ^* to the final steering reaction force command value T ^* is 100%, and the ratio of the first steering reaction force command value T ₁ ^* is 0%. . That is, the second steering reaction force command value T ₂ ^* is used as is as the final steering reaction force command value T ^* .

Further, when the value of the flag as the distribution command S _r is "0", the control manager 91 sets the value of the distribution ratio DR _a to "0" and the value of the distribution ratio DR _m to "1" according to the product specifications etc. ”. In this case, the ratio of the second steering reaction force command value T ₂ ^* to the final steering reaction force command value T ^* is 0%, and the ratio of the first steering reaction force command value T ₁ ^* is 100%. . That is, the first steering reaction force command value T ₁ ^* is used as is as the final steering reaction force command value T ^* .

In this way, similarly to the first comparative example or the second comparative example, the first steering reaction force command is used as the final steering reaction force command value T ^* during automatic operation and manual operation. It can also be used by switching between the value T ₁ ^* and the second steering reaction force command value T ₂ ^* .

Note that it is also conceivable that the control device 50 is supplied with the automatic operation rate instead of the flag (“0” or “1”) as the distribution command _Sr from the host control device 500. In this case, the control manager 91 may set the values of the two distribution ratios DR _m and DR _a according to the automatic driving rate depending on the content of driving support or automatic driving. The automatic driving rate refers to a value indicating the degree of involvement of the system in driving the vehicle (here, the degree of involvement of the higher-level control device 500 in steering control). As driving support systems become more complex or sophisticated as the level of technology increases, the degree of involvement of the system in driving increases. For example, when the automatic driving rate is 100%, the system completely replaces driving. Conversely, when the automatic driving rate is 0%, the driver performs all recognition of the driving environment, risk judgment, and vehicle driving operations (steering, acceleration/deceleration, etc.). The host control device 500 sets, for example, a value in the range of "0 (0%) to 1 (100%)" in increments of "0.1" as the automatic operation rate.

The control manager 91 directly sets the value of the automatic operation rate as the distribution ratio DR _a for the second steering reaction force command value T ₂ ^* , while setting the value of the automatic operation rate as the distribution ratio DR a to the second steering reaction force command value T 2 *. The distribution ratio DR _m for the first steering reaction force command value T ₁ ^* is calculated by subtracting the value of the automatic operation rate as the distribution ratio DR _a from "100%)".

For example, when the value of the automatic operation rate is "1 (100%)", the value of the distribution ratio DR _m with respect to the first steering reaction force command value T ₁ ^* is set to "0 (0%)". Furthermore, when the value of the automatic operation rate is "0.7 (70%)", the value of the distribution ratio DR _m with respect to the first steering reaction force command value T ₁ ^* is "0.3 (30%)". Set. Furthermore, when the value of the automatic operation rate is "0.3 (30%)", the value of the distribution ratio DR _m to the first steering reaction force command value T ₁ ^* is "0.7 (70%)". Set. Furthermore, when the value of the automatic driving rate is "0 (0%)", that is, when the driving support control function or the automatic driving control function is turned off, the distribution ratio to the first steering reaction force command value T ₁ ^* The value of DR _m is set to "1 (100%)".

<Effects of the first embodiment>
Therefore, according to the first embodiment, the following effects can be obtained.
(1) As described above, the control manager 91 can appropriately set the values of the two distribution ratios DR _m and DR _a in the range of "0" to "1" in increments of "0.1". . Therefore, during automatic operation and manual operation, the first steering reaction force that accounts for the final steering reaction force command value T ^* is determined by the values of the two distribution ratios DR _m and DR _a calculated by the control manager 91. The ratio of the command value T ₁ ^* and the second steering reaction force command value T ₂ ^* is set, for example, from "T ₁ ^* : T ₂ ^* = 100%: 0%" to "T ₁ ^* : T ₂ ^* = 0%: It can be freely changed within the range of 100%. Therefore, according to the control device 50, it is possible to increase the scope for adjusting the torque of the reaction force motor 31. Further, it is possible to generate a more appropriate steering reaction force according to product specifications.

<Second embodiment>
Next, a second embodiment of the steering control device will be described. This embodiment differs from the first embodiment in the configuration of the arbitration processing section 76.

As shown in FIG. 7, the arbitration processing section 76 includes two gradual change processing sections 95 and 96 in addition to two multipliers 92 and 93 and an adder 94. The gradual change processing section 95 is provided in the calculation path between the control manager 91 and the multiplier 92. The gradual change processing unit 95 performs gradual change processing (processing for gradually changing) with respect to time on the change in the distribution ratio DR _m calculated by the control manager 91 . The gradual change processing section 96 is provided in the calculation path between the control manager 91 and the multiplier 93. The gradual change processing unit 96 performs gradual change processing with respect to time on the change in the distribution ratio DR _a calculated by the control manager 91 .

As the gradual change processing units 95 and 96, the following configuration (a1) or (a2) is adopted.
(a1) The gradual change processing units 95 and 96 have a so-called change amount guard function with respect to time, which limits the amount of change in the distribution ratios DR _m and DR _a per unit time to a predetermined limit value. However, the gradual change processing units 95 and 96 may change the limit value according to the steering speed, target steering speed, steering torque, or steering torque differential value. For example, the gradual change processing units 95 and 96 set the limit values so that the faster the steering speed is, the faster the distribution ratios DR _{m and} DR _a are changed, and the slower the steering speed is, the slower the distribution ratios DR m and DR _a are. Set.

(a2) A low-pass filter is employed as the gradual change processing units 95 and 96. However, the cutoff frequency of the low-pass filter may be changeable depending on the steering speed, target steering speed, steering torque, or steering torque differential value.

Therefore, according to the second embodiment, in addition to the effect (1) of the first embodiment, the following effect can be obtained.
(2) For example, when switching from automatic operation to manual operation, the distribution ratio DR _m is switched from "0" to "1", while the distribution ratio DR _a is switched from "1" to "0". When the final steering reaction force command value T ^* changes immediately from the second steering reaction force command value T ₂ ^* to the first steering reaction force command value T ₁ ^* , there is a possibility that the steering reaction force changes suddenly. There is. This is because when a driving support system or an automatic driving system is installed in a vehicle, the steering reaction force generated by the reaction force motor 31 affects the behavior of the steering wheel 11, so when the driver performs manual driving. This is because the requirements for the reaction force control executed by the control device 50 may differ depending on when driving support or automatic driving is performed.

In this regard, in this embodiment, when the driving support control function or the automatic driving control function is switched between on and off, the distribution ratio DR _m , Rapid changes in DR _a are suppressed. That is, the steering reaction force command value T ^* , and thus the steering reaction force applied to the steering wheel 11, is prevented from changing rapidly. Therefore, switching between driving support or automatic driving and manual driving can be performed smoothly. In other words, between the steering reaction force for automatic operation based on the second steering reaction force command value T ₂ ^* and the steering reaction force for manual operation based on the first steering reaction force command value T ₁ ^* . Steering reaction force can be smoothly changed. Therefore, the driver is less likely to feel discomfort due to changes in the steering reaction force.

<Third embodiment>
Next, a third embodiment of the steering control device will be described. This embodiment differs from the first embodiment in the trigger for changing the two distribution ratios DR _m and DR _a . Incidentally, this embodiment can also be applied to the second embodiment.

As shown in FIG. 8, the control device 50 includes an abnormality detection section 97. The abnormality detection unit 97 detects an abnormality in the rotation angle sensor 33 and an abnormality in the torque sensor 34. The abnormality detection unit 97 generates an abnormality detection signal S _d indicating whether the rotation angle sensor 33 and the torque sensor 34 are respectively normal or abnormal as a result of detecting abnormalities in the rotation angle sensor 33 and the torque sensor 34 . Note that the abnormality detection signal S _d corresponds to an external command instructing the steering state of the vehicle when the rotation angle sensor 33 and the torque sensor 34 are abnormal.

When the abnormality detection signal S _d indicates an abnormality in the rotation angle sensor 33 , the control manager 91 determines the distribution ratio DR _m for the first steering reaction force command value T ₁ ^* calculated by the torque feedback control unit 72 . The distribution ratio DR _a for the second steering reaction force command value T ₂ ^* calculated by the steering angle feedback control unit 75 is set to "1" and "0". As a result, the ratio of the first steering reaction force command value T ₁ ^* to the final steering reaction force command value T ^* is 100%, and the ratio of the second steering reaction force command value T ₂ ^* is 0%. . That is, the first steering reaction force command value T ₁ ^* is used as is as the final steering reaction force command value T ^* . The reaction force motor 31 is supplied with electric power according to the first steering reaction force command value T ₁ ^* through the energization control section 53 .

When the abnormality detection signal S _d indicates an abnormality in the torque sensor 34 , the control manager 91 sets the distribution ratio DR _m to the first steering reaction force command value T ₁ ^* calculated by the torque feedback control unit 72 as “ 0'', and the distribution ratio DR _a for the second steering reaction force command value T ₂ ^* calculated by the steering angle feedback control unit 75 is set to ``1''. As a result, the ratio of the first steering reaction force command value T ₁ ^* to the final steering reaction force command value T ^* is 0%, and the ratio of the second steering reaction force command value T ₂ ^* is 100%. . That is, the second steering reaction force command value T ₂ ^* is used as is as the final steering reaction force command value T ^* . The reaction force motor 31 is supplied with electric power according to the second steering reaction force command value T ₂ ^* through the energization control section 53 .

The second steering reaction force command value T ₂ ^* is determined using the steering angle θ _s calculated based on the rotation angle _{θ a} of the reaction force motor 31 . Therefore, if the rotation angle sensor 33 is abnormal, the value of the steering angle θ _s detected through the rotation angle sensor 33, and the second steering reaction force command value calculated using the steering angle θ _s . There is a possibility that T ₂ ^* may take an abnormal value. Therefore, when an abnormality in the rotation angle sensor 33 is detected, the second steering reaction force command value T ₂ ^* , which is affected by the rotation angle θ _a of the reaction force motor 31 detected through the rotation angle sensor 33, is not used. It is preferable. Even in this case, since the reaction force motor 31 is supplied with electric power according to the first steering reaction force command value T ₁ ^* , the reaction force motor 31 responds to the first steering reaction force command value T ₁ ^* . It is possible to generate a large amount of torque.

The first steering reaction force command value T ₁ ^* is determined using the steering torque T _h detected through the torque sensor 34 . Therefore, when the torque sensor 34 is abnormal, the value of the steering torque _Th detected through the torque sensor 34, and the first steering reaction force command value _T1 calculated using the steering torque _Th . ^* may be an abnormal value. Therefore, when an abnormality in the torque sensor 34 is detected, it is preferable not to use the first steering reaction force command value T ₁ ^* , which is influenced by the steering torque T _h detected through the torque sensor 34 . Even in this case, since the reaction force motor 31 is supplied with electric power according to the second steering reaction force command value T ₂ ^* , the reaction force motor 31 responds to the second steering reaction force command value T ₂ ^* . It is possible to generate a large amount of torque.

As shown by the two-dot chain line in FIG. 8, when this embodiment is applied to the second embodiment, a gradual change processing section 95 is provided in the calculation path between the control manager 91 and the multiplier 92. , a gradual change processing section 96 is provided in the calculation path between the control manager 91 and the multiplier 93. Therefore, when an abnormality in the rotation angle sensor 33 or the torque sensor 34 is detected, the distribution ratio DR _a to the second steering reaction force command value T ₂ ^* or the distribution ratio to the first steering reaction force command value T ₁ ^* Even when DR _m is switched between "0" and "1", rapid changes in the distribution ratios DR _m and DR _a are suppressed through execution of gradual change processing by the gradual change processing units 95 and 96. . Therefore, the steering reaction force command value T ^* , and thus the steering reaction force applied to the steering wheel 11, is prevented from changing rapidly.

<Effects of the third embodiment>
Therefore, according to the third embodiment, in addition to the effect (1) of the first embodiment, the following effect can be obtained.

(3) The first steering reaction force command value T ₁ ^* or the second steering reaction force command value T ₂ ^* based on the detection result of the sensor (33, 34) in which an abnormality has been detected is the final steering reaction force command Not used in the calculation of the value T ^* . That is, the detection result of a sensor in which an abnormality has been detected is not reflected in the final steering reaction force command value T ^* , and the reaction force motor 31 receives a steering reaction force command in which the detection result of a normal sensor is reflected. Power is supplied according to the value T ^* . Therefore, even if an abnormality occurs in either one of the two sensors, it is possible to suppress the reaction motor 31 from generating abnormal torque.

(4) As described above, the demand for the torque generated by the reaction motor 31 may differ depending on whether an abnormality occurs in the sensors (33, 34) or not. According to the present embodiment, based on the abnormality detection signal S _d generated by the abnormality detection unit 97, the distribution ratio DR _m to the first steering reaction force command value T ₁ ^* and the second steering reaction force command value T are determined. A distribution ratio DR _a for ₂ ^* is set respectively. For this reason, the final first ^steering reaction force command value T ₁ ^* and the second The steering reaction force command value T ₂ ^* changes. That is, when an abnormality occurs in either one of the two sensors, the torque generated by the reaction force motor 31 is changed according to the distribution ratio (DR _m , DR _a ). Therefore, it is possible to appropriately respond to abnormalities in the two sensors.

<Fourth embodiment>
Next, a fourth embodiment of the steering control device will be described. This embodiment differs from the first embodiment in that power supply to a motor having two systems of coils is controlled.

As shown in FIG. 9, the reaction motor 31 has a rotor 31a, a first winding group 31b and a second winding group 31c wound around a stator (not shown). The first winding group 31b includes a U-phase coil, a V-phase coil, and a W-phase coil. The second winding group 31c also includes a U-phase coil, a V-phase coil, and a W-phase coil.

The reaction force control unit 50a independently controls power feeding to the first winding group 31b and the second winding group 31c for each system. The reaction motor 31 as a whole generates a torque that is the total of the torque generated by the first winding group 31b and the torque generated by the second winding group 31c. The reaction force control section 50a includes a first reaction force control section 50a1 and a second reaction force control section 50a2.

The first reaction force control unit 50a1 controls the steering torque T _h1 detected through the first torque sensor 34a, the vehicle speed V detected through the vehicle speed sensor 501, and the rotation of the reaction force motor 31 detected through the rotation angle sensor 33a. The angle θ _a1 is taken in, and the steering torque T _h1 , the vehicle speed V, and the rotation angle θ _a1 of the reaction force motor 31 are used to control the power supply to the first winding group 31b.

The second reaction force control unit 50a2 controls the steering torque T _h2 detected through the second torque sensor 34b, the vehicle speed V detected through the vehicle speed sensor 501, and the rotation of the reaction force motor 31 detected through the rotation angle sensor 33b. The steering torque T _{h2 ,} the vehicle speed V, and the rotation angle θ _a2 of the reaction motor 31 are used to control the power supply to the second winding group 31c.

The first reaction force control section 50a1 and the second reaction force control section 50a2 basically have the same configuration as the reaction force control section 50a of the first embodiment shown in FIG. There is.
As shown in FIG. 10, the steering reaction force command value calculation section 52a of the first reaction force control section 50a1 and the steering reaction force command value calculation section 52b of the second reaction force control section 50a2 are configured as shown in FIG. It has the same configuration as the first embodiment shown in . However, in FIG. 10, only the main parts of the steering reaction force command value calculation sections 52a and 52b are shown.

The steering reaction force command value calculation section 52a includes a torque feedback control section 72a, a steering angle feedback control section 75a, an arbitration processing section 76a, and a control manager 91a. The torque feedback control unit 72a calculates the first steering reaction force command value T _1a ^* through feedback control of the steering torque T _h1 in order to cause the steering torque T _h1 to follow the target steering torque T _h1 ^* . The steering angle feedback control unit 75a calculates the second steering reaction force command value T _2a ^* through feedback control of the steering angle θ _s in order to cause the steering angle θ _s to follow the target steering angle θ ₁ ^* . As in the first embodiment, the control manager 91a determines the distribution ratio DR _m1 for the first steering reaction force command value T _1a ^* calculated by the torque feedback control unit 72a, and the steering angle feedback control unit 75a. The distribution ratio DR _a1 for the second steering reaction force command value T _2a ^* calculated by is calculated. The arbitration processing unit 76a multiplies the first steering reaction force command value T _1a ^* by the distribution ratio DR _m1 and the second steering reaction force command value T _2a ^* by the distribution ratio DR _a1 . By adding them up, the final steering reaction force command value T _a ^* is calculated.

The steering reaction force command value calculation section 52b includes a torque feedback control section 72b, a steering angle feedback control section 75b, an arbitration processing section 76b, and a control manager 91b. The torque feedback control unit 72b calculates the first steering reaction force command value T _1b ^* through feedback control of the steering torque T _h2 in order to cause the steering torque T _h2 to follow the target steering torque T _h2 ^* . The steering angle feedback control unit 75b calculates a second steering reaction force command value T _2b ^* through feedback control of the steering angle θ _s in order to cause the steering angle θ _s to follow the target steering angle θ ₂ ^* . As in the first embodiment, the control manager 91b controls the distribution ratio DR _m2 for the first steering reaction force command value T _1b ^* calculated by the torque feedback control unit 72b, and the steering angle feedback control unit 75b. The distribution ratio DR _a2 for the second steering reaction force command value T _2b ^* calculated by is calculated. The arbitration processing unit 76b multiplies the first steering reaction force command value T _1b ^* by the distribution ratio DR _m2 and the second steering reaction force command value T _2b ^* by the distribution ratio DR _a2 . By adding them up, the final steering reaction force command value T _b ^* is calculated.

Further, the first reaction force control section 50a1 has an abnormality detection section 98a, and the second reaction force control section 50a2 has an abnormality detection section 98b. The abnormality detection unit 98a detects an abnormality in the power supply system for the first winding group 31b including each part of the first reaction force control unit 50a1, and generates an abnormality detection signal S _d1 as a result of the detection of the abnormality. The abnormality detection unit 98b detects an abnormality in the power supply system for the second winding group 31c including each part of the second reaction force control unit 50a2, and generates an abnormality detection signal S _d2 as a result of the detection of the abnormality. These abnormality detection units 98a and 98b exchange the generated abnormality detection signals S _d1 and S _d2 with each other and transmit them to the corresponding control managers 91a and 91b, respectively. Note that the abnormality detection signals S _d1 and S _d2 correspond to external commands that instruct the steering state of the vehicle when the power supply system for the first winding group 31b and the second winding group 31c is normal or abnormal. .

Next, the operation of the fourth embodiment will be explained. Here, the torque required to be generated by the reaction motor 31 is covered in half by the torque generated by the first winding group 31b and the torque generated by the second winding group 31c.

When the two abnormality detection signals S _d1 and S _d2 both indicate normality, the control manager 91a of the first reaction force control unit 50a1 sets the values of the two distribution ratios DR _m1 and DR _a1 to “0,” respectively. .5”. The arbitration processing unit 76a multiplies the first steering reaction force command value T _1a ^* by the distribution ratio DR _m1 and the second steering reaction force command value T _2a ^* by the distribution ratio DR _a1 . By adding them up, the steering reaction force command value T _a ^* is calculated. Electric power corresponding to the steering reaction force command value T _a ^* is supplied to the first winding group 31b. Thereby, the first winding group 31b generates torque according to the steering reaction force command value T _a ^* .

When the two abnormality detection signals S _d1 and S _d2 both indicate normality, the control manager 91b of the second reaction force control unit 50a2 sets the values of the two distribution ratios DR _m2 and DR _a2 to "0", respectively. .5”. The arbitration processing unit 76a multiplies the first steering reaction force command value T _1b ^* by the distribution ratio DR _m2 and the second steering reaction force command value T _2b ^* by the distribution ratio DR _a2 . By adding them up, the steering reaction force command value T _b ^* is calculated. Electric power corresponding to the steering reaction force command value T _b ^* is supplied to the second winding group 31c. Thereby, the second winding group 31c generates torque according to the steering reaction force command value T _b ^* .

When the abnormality detection signal S _d1 indicates normality and the abnormality detection signal S _d2 indicates abnormality, the control manager 91a of the first reaction force control unit 50a1 changes the values of the two distribution ratios DR _m1 and DR _a1 to their original values. is set to "1" which is twice the value of "0.5". Therefore, the steering reaction force command value T _a ^* calculated by the arbitration processing unit 76a is twice the value compared to the normal state in which both the two abnormality detection signals S _d1 and S _d2 indicate normality. Since the first winding group 31b is supplied with twice as much power as normal, the torque generated by the first winding group 31b is also twice as much as normal.

When the abnormality detection signal S _d1 indicates normality and the abnormality detection signal S _d2 indicates abnormality, the control manager 91b of the second reaction force control unit 50a2 changes the values of the two distribution ratios DR _m2 and DR _a2 to their original values. change from "0.5" to "0". Therefore, the steering reaction force command value T _b ^* calculated by the arbitration processing unit 76a becomes "0". Since no power is supplied to the second winding group 31c, the torque generated by the second winding group 31c is "0". However, since the first winding group 31b generates twice as much torque as when it is normal, the torque generated by the reaction motor 31 as a whole is the same as when it is normal.

Contrary to the above, even when the abnormality detection signal S _d1 indicates abnormality and the abnormality detection signal S _d2 indicates normality, the distribution ratios DR _m1 , DR _a1 , DR _m2 , DR _a2 are determined by the control managers 91a and 91b. Through the adjustment, the torque generated by the winding group in the normal system is set to twice the normal torque, and the torque generated by the winding group in the abnormal system is set to "0".

<Effects of the fourth embodiment>
Therefore, according to the fourth embodiment, in addition to the effect (1) of the first embodiment, the following effect can be obtained.

(5) If _an abnormality _occurs in one of the two _power supply systems, the winding _group of the normal system is The torque generated by the winding group of the abnormal system is assumed to be twice that of the normal one, and the torque generated by the winding group of the abnormal system is assumed to be "0". Therefore, fail-safe operation is achieved by not using the abnormal system, and the torque generated by the reaction motor 31 as a whole can be maintained at the same level as during normal operation.

(6) The requirements for the torque generated by the winding groups (31b, 31c) of each power supply system may differ depending on whether or not an abnormality occurs in one of the two power supply systems. According to the present embodiment, based on the abnormality detection signals S _d1 and S _d2 generated by the abnormality detection units _98a and _98b , the first steering reaction force command values (T _1a ^* , T _1b ^* ) and distribution ratios (DR _m1 , DR _a1 , DR _m2 , DR _a2 ) of the first steering reaction force command values (T _2a ^* , T _2b ^* ). are set respectively. As a result, the final first command value and the final command value to be reflected in the command value for each of the winding groups of the multiple power supply systems, depending on whether or not an abnormality occurs in one of the multiple power supply systems. The value of command value 2 changes. That is, when an abnormality occurs in one of the two power supply systems, the torque generated by the reaction force motor 31 is changed according to the distribution command. Therefore, it is possible to appropriately respond to an abnormality in either one of the two power supply systems.

<Fifth embodiment>
Next, a fifth embodiment of the steering control device will be described. This embodiment differs from the first embodiment in the configuration of the steering reaction force command value calculation section 52.

As shown in FIG. 11, the steering reaction force command value calculation section 52 includes a control manager 91, an axial force calculation section 73, and a target steering angle calculation section 74, as in the first embodiment (see FIG. 3). , a steering angle feedback control section 75, and an arbitration processing section 76. Further, the steering reaction force command value calculation unit 52 includes a target steering reaction force calculation unit 99 in place of the target steering torque calculation unit 71 and the torque feedback control unit 72 in the first embodiment. The target steering reaction force calculation unit 99 calculates a target steering reaction force as a first steering reaction force command value T ₁ ^* based on the steering torque T _h and the vehicle speed V.

Incidentally, the target steering reaction force calculation unit 99 takes in the axial force F _ax of the steered shaft 14 calculated by the axial force calculation unit 73 in addition to the steering torque _Th and the vehicle speed V, and calculates the steering torque _Th to be taken in. , the first steering reaction force command value T ₁ ^* as the target steering reaction force may be calculated based on the vehicle speed V and the axial force F _ax . Further, the target steering reaction force calculation section 99 does not take in the steering torque _Th and the vehicle speed V, but takes in only the axial force F _ax calculated by the axial force calculation section 73, and performs the target steering based on the taken in axial force F _ax . The first steering reaction force command value T ₁ ^* as the reaction force may be calculated.

Therefore, according to the fifth embodiment, the same effect as (1) in the first embodiment can be obtained in the control device 50 of a type that does not perform feedback control of the steering torque T _h .

<Sixth embodiment>
Next, a sixth embodiment will be described in which the steering control device is implemented as a control device for an EPS (electric power steering device). Note that the same members as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

In the EPS, the steering wheel 11 and steered wheels 16, 16 shown in FIG. 1 are mechanically connected. That is, the steering shaft 12, the pinion shaft 13, and the steered shaft 14 function as a power transmission path between the steering wheel 11 and the steered wheels 16, 16. As the steered shaft 14 moves linearly as the steering wheel 11 is rotated, the steered angle θ _w of the steered wheels 16, 16 is changed. Further, the EPS includes an assist motor provided at the same position as either the reaction force motor 31 or the steering motor 41 shown in FIG. The assist motor generates steering assist force (assist force).

As shown in FIG. 12, the control device 101 of the EPS 100 executes assist control to generate a steering assist force according to the steering torque _Th through power supply control to the assist motor 102. The control device 101 controls the assist motor based on the steering torque T _h detected through the torque sensor 34 , the vehicle speed V detected through the vehicle speed sensor 501 , and the rotation angle θ _m detected through the rotation angle sensor 103 provided in the assist motor 102 . Controls power supply to 102.

The control device 101 includes a pinion angle calculation section 111, an assist command value calculation section 112, and an energization control section 113. The pinion angle calculation unit 111 takes in the rotation angle θ _m of the assist motor 102 and calculates the pinion angle θ _p , which is the rotation angle of the pinion shaft 13, based on the rotation angle θ _m . The assist command value calculation unit 112 calculates an assist command value T _as ^* based on the steering torque T _h and the vehicle speed V. The assist command value T _as ^* is a command value indicating the assist torque that is the rotational force that the assist motor 102 should generate. The energization control unit 113 supplies electric power to the assist motor 102 according to the assist command value T _as ^* . A current sensor 114 is provided on the power supply path to the assist motor 102. Current sensor 114 detects a current value I _m that is the actual value of current supplied to assist motor 102 .

Next, the configuration of the assist command value calculation section 112 will be explained in detail.
The assist command value calculation section 112 includes an assist torque calculation section 121, an axial force calculation section 122, a target pinion angle calculation section 123, a pinion angle feedback control section (pinion angle F/B control section) 124, a control manager 125, and an arbitration processing section. It has a section 126.

The assist torque calculation unit 121 calculates a first assist torque T _as1 ^* based on the steering torque T _h . The assist torque calculation section 121 includes an adder 131, a target steering torque calculation section 132, and a torque feedback control section 133. The adder 131 adds the steering torque T _h detected through the torque sensor 34 and the first assist torque T _as1 ^* calculated by the torque feedback control unit 133 to obtain the torque to be applied to the steering shaft 12. The input torque T _in ^* is calculated. The target steering torque calculating section 132 calculates a target steering torque T _h ^* based on the input torque T _in ^* calculated by the adder 131 . The target steering torque calculation unit 132 calculates a target steering torque T _h ^* having a larger absolute value as the absolute value of the input torque T _{in *} becomes larger ^. The torque feedback control unit 133 takes in the steering torque T _h detected through the torque sensor 34 and the target steering torque T _h ^* calculated by the target steering torque calculation unit 132. The torque feedback control unit 133 controls the first assist torque T _as1 ^* through feedback control (PID control) of the steering torque T _h so that the steering torque T _h detected through the torque sensor 34 follows the target steering torque T _h ^* . calculate.

Incidentally, the following configuration may be adopted as the assist torque calculation section 121. That is, the assist torque calculation unit 121 uses a three-dimensional map that defines the relationship between the steering torque T _h and the first assist torque T _as1 ^* according to the vehicle speed V, instead of performing feedback control of the steering torque T _h . , calculates the first assist torque T _as1 ^* . The assist torque calculation unit 121 sets the absolute value of the first assist torque T _as1 ^* to a larger value as the absolute value of the steering torque T _h increases and as the vehicle speed V decreases.

The axial force calculation section 122 has the same function as the axial force calculation section 73 of the first embodiment shown in FIG. 3 above. The axial force calculation unit 122 calculates the current value I _m of the assist motor 102 detected through the current sensor 114, the target pinion angle θ _p ^* calculated by the target pinion angle calculation unit 123, and the vehicle speed V detected through the vehicle speed sensor 501. is taken in, and the axial force F _ax acting on the steered shaft 14 is calculated based on the current value I _m of the assist motor 102, the target pinion angle θ _p ^* , and the vehicle speed V.

The target pinion angle calculation section 123 has the same function as the target steering angle calculation section 74 of the first embodiment shown in FIG. 3 above. The target pinion angle calculation unit 123 calculates the first assist torque T _as1 ^* calculated by the assist torque calculation unit 121, the steering torque T _h detected through the torque sensor 34, and the axial force calculated by the axial force calculation unit 122. Using F _ax , the target pinion angle θ _p ^* is calculated based on the ideal model expressed by the above equation (A).

The pinion angle feedback control section 124 has the same function as the steering angle feedback control section 75 of the first embodiment shown in FIG. 3 above. The pinion angle feedback control unit 124 takes in the target pinion angle θ _p ^* calculated by the target pinion angle calculation unit 123 and the actual pinion angle θ _p calculated by the pinion angle calculation unit 111, respectively. The pinion angle feedback control unit 124 performs PID (proportional, integral, differential) control as feedback control of the pinion angle θ _p so that the actual pinion angle θ _p follows the target pinion angle θ _p ^* . That is, the pinion angle feedback control unit 124 calculates the deviation between the target pinion angle θ _p ^* and the actual pinion angle θ _p and calculates the second assist torque T _as2 ^* so as to eliminate the deviation.

The control manager 125 has the same functions as the control manager 91 of the first embodiment shown in FIG. 6 above. The control manager 125 takes in the flag as the distribution command S _r generated by the higher-level control device 500 . The control manager 125 calculates two distribution ratios DR _as1 and DR _as2 according to multiple types of state variables that reflect vehicle behavior, road surface conditions, or steering conditions. The distribution ratio DR _as1 is for the first assist torque T _as1 ^* calculated by the assist torque calculation unit 121. The distribution ratio DR _as2 is for the second assist torque T _as2 ^* calculated by the pinion angle feedback control unit 124.

The arbitration processing unit 126 has the same function as the arbitration processing unit 76 of the first embodiment shown in FIG. 6 above. The arbitration processing unit 126 adds up the value obtained by multiplying the first assist torque T _as1 ^* by the distribution ratio DR _as1 and the value obtained by multiplying the second assist torque T _as2 ^* by the distribution ratio DR _as2 to determine the final result. A typical assist command value T _as ^* is calculated.

The energization control unit 113 calculates a current command value for the assist motor 102 based on the assist command value T _as ^* . Further, the energization control unit 113 takes in the current value _Im detected through the current sensor 114. Then, the energization control unit 113 determines the deviation between the current command value and the actual current value _Im , and controls the power supply to the assist motor 102 so as to eliminate the deviation. As a result, the assist motor 102 generates torque according to the assist command value T _as ^* . That is, steering assist is performed according to the steering state.

Therefore, according to the sixth embodiment, in a steering device that mechanically connects power transmission between the steering wheel 11 and steered wheels 16, 16, (1) in the first embodiment is provided. A similar effect can be obtained. That is, according to the control device 101 of the EPS 100, it is possible to increase the scope for adjusting the torque of the assist motor 102. Furthermore, it is possible to generate more appropriate assist force according to product specifications.

<Other embodiments>
Note that each of the embodiments described above may be modified and implemented as follows.
- In the third embodiment, when the abnormality detection signal _Sd indicates an abnormality in the torque sensor 34, the control manager 91 sets the first steering reaction force command value T calculated by the torque feedback control unit 72. The distribution ratio DR _m for ₁ ^* may be reduced to a value smaller than the original value instead of "0". Furthermore, when the abnormality detection signal S _d indicates an abnormality in the rotation angle sensor 33, the control manager 91 determines the distribution ratio for the second steering reaction force command value T ₂ ^* calculated by the steering angle feedback control unit 75. DR _a may be decreased to a value smaller than the original value instead of "0".

- In the fourth embodiment, when the abnormality detection signal S _d2 indicates normality and the abnormality detection signal S _d1 indicates abnormality, the control manager 91a of the first reaction force control unit 50a1 sets two distribution ratios DR. The values of _m1 and DR _a1 may be decreased not to "0" but to a value greater than "0" and smaller than the original value "0.5". When the abnormality detection signal S _d1 indicates normality and the abnormality detection signal S _d2 indicates abnormality, the control manager 91b of the second reaction force control unit 50a2 sets the values of the two distribution ratios DR _m2 and DR _a2 as “ Instead of "0", the value may be decreased to a value larger than "0" and smaller than the original value "0.5".

- In the first to fifth embodiments, the steering device 10 may be provided with a clutch. In this case, the steering shaft 12 and pinion shaft 13 are connected via the clutch 21, as shown by the two-dot chain line in FIG. As the clutch 21, an electromagnetic clutch is employed that cuts and cuts power by turning on and off electricity to an excitation coil. The control device 50 executes intermittent control that switches the clutch 21 on and off. When the clutch 21 is disconnected, power transmission between the steering wheel 11 and the steered wheels 16, 16 is mechanically disconnected. When clutch 21 is connected, power transmission between steering wheel 11 and steered wheels 16, 16 is mechanically coupled.

- In the first to sixth embodiments, it is also assumed that the host control device 500 calculates an additional torque command value instead of an additional angle command value as the command value S ^* . In this case, the steering reaction force command value calculation unit 52 of the first to fifth embodiments and the assist command value calculation unit 112 of the sixth embodiment convert the additional torque command value into an additional angle command value, This converted additional angle command value may be used. However, the steering reaction force command value calculation unit 52 and the assist command value calculation unit 112 are provided with a conversion unit that converts the additional torque command value into an additional angle command value.

DESCRIPTION OF SYMBOLS 10... Steering device, 11... Steering wheel, 12... Steering shaft (shaft) which constitutes a steering mechanism, 14... Steering shaft which constitutes a steering mechanism, 16... Steered wheel, 31... Reaction force motor (motor), 31b... 1st winding group, 31c...2nd winding group, 33...rotation angle sensor (second sensor), 34...torque sensor (first sensor), 41...steering motor, 44...pinion shaft ( shaft), 50, 100...control device (steering control device), 50a...reaction force control section (control section), 50a1...first reaction force control section, 50a2...second reaction force control section, 72...torque feedback Control unit (first calculation unit), 75... Rudder angle feedback control unit (second calculation unit), 76... Arbitration processing unit (fourth calculation unit), 91... Control manager (third calculation unit), 95... Gradual change processing section (first gradual change processing section), 96... Gradual change processing section (second gradual change processing section), 97, 98a, 98b... Abnormality detection section, 102... Assist motor, 500... Upper order Control device, DR _m ...Allocation ratio (first allocation ratio), DR _a ...Allocation ratio (second allocation ratio), S _d, S _d1, S _d2 ... Abnormality detection signal (external command), S _r ... Allocation Command (external command), T ^* ...Steering reaction force command value, T1 _* ^... First steering reaction force command value (first command value), _T2 ^* ...Second steering reaction force command value (second command value), T _h ...steering torque, θ _p ... pinion angle, θ _s ... steering angle.

Claims (9)

A steering control device having a control unit that controls a motor, which is a source of a driving force applied to a steering mechanism of a vehicle, based on a command value calculated according to a steering state,
The control unit includes:
a first calculation unit that calculates a first command value that is reflected in the command value according to the steering state;
a second calculation unit that calculates a second command value that is reflected in the command value according to the steering state;
a third calculation unit that calculates a first distribution ratio for the first command value and a second distribution ratio for the second command value in response to an external command instructing a steering state of the vehicle;
A fourth method of calculating the command value by adding together a value obtained by multiplying the first command value by the first distribution ratio and a value obtained by multiplying the second command value by the second distribution ratio. It has an arithmetic unit ;
The first calculation unit calculates the first command value through feedback control of steering torque detected through a first sensor mounted on the vehicle;
The second calculation unit is a steering control device that calculates the second command value through feedback control of a steering angle detected through a second sensor mounted on the vehicle. When the value of the first distribution ratio calculated by the third calculation unit is changed, it is gradually changed from the first distribution ratio before the change to the first distribution ratio after the change. a first gradual change processing section;
When the value of the second distribution ratio calculated by the third calculation unit is changed, it is gradually changed from the second distribution ratio before the change to the second distribution ratio after the change. The steering control device according to claim 1, further comprising a second gradual change processing section. The control unit is configured to execute steering control based on a distribution command generated when a higher-level control device mounted on the vehicle intervenes in steering control,
The steering control device according to claim 1 or 2, wherein the external command includes the distribution command. comprising an abnormality detection unit that detects an abnormality in the first sensor and the second sensor,
The steering control device according to any one of claims 1 to 3, wherein the external command includes an abnormality detection signal generated by the abnormality detection section. The third calculation unit is
When an abnormality in either the first sensor or the second sensor is detected through the abnormality detection unit,
While reducing the allocation ratio for either the first command value or the second command value obtained through the use of the sensor in which the abnormality has been detected;
The steering control device according to claim 4, wherein a distribution ratio for one of the first command value and the second command value obtained through use of a sensor in which no abnormality is detected is increased. Assuming that the motor has multiple winding groups,
the same number of control units as the number of systems that independently control power feeding to the winding groups of the plurality of systems for each system;
an abnormality detection unit that independently detects abnormalities in a plurality of power supply systems including the control unit for each system,
The steering control device according to any one of claims 1 to 3, wherein the external command includes an abnormality detection signal generated by the abnormality detection section. When an abnormality in any one of the plurality of power supply systems is detected through the abnormality detection unit,
The control unit of the abnormal system reduces the allocation ratio for the first command value and the second command value to be reflected in the command value for the winding group of the self system that is abnormal, while
7. The control unit of the normal system increases a distribution ratio for each of the first command value and the second command value to be reflected in the command value for the winding group of the self-system that is normal. Steering control device. The steering mechanism includes a steering shaft that rotates in conjunction with the operation of a steering wheel, and in which power transmission between the steering shaft and the steered wheels is separated;
The motor is a reaction force motor that generates a steering reaction force that is a torque in a direction opposite to the steering direction as the driving force applied to the steering shaft, according to any one of claims 1 to 7. steering control device. The steering mechanism includes a shaft that rotates in conjunction with the operation of a steering wheel, and a steering shaft that steers steered wheels in conjunction with the rotation of the shaft,
The motor is an assist motor that generates a steering assist force that is a torque in the same direction as the steering direction as the driving force applied to the shaft or the steered shaft. The steering control device described in .