JP7147472B2 - steering controller - Google Patents

Description

The present invention relates to a steering control device.

Conventionally, as one type of steering system, there is a steer-by-wire system in which power transmission between a steering section steered by a driver and a steering section for turning steered wheels according to steering by the driver is separated. . In such a steering system, the road surface reaction force and the like received by the steered wheels are not mechanically transmitted to the steering wheel. Therefore, in a steering control device that controls the same type of steering device, a steering-side actuator (steering-side motor) applies a steering reaction force that takes into account the road surface reaction force and the like to the steering wheel. to the driver.

For example, Patent Document 1 discloses a steering control device that focuses on the axial force acting on a steered shaft connected to steered wheels and calculates a steering reaction force based on the distributed axial force obtained by distributing a plurality of types of axial force. It is As such an axial force, the document describes an angular axial force based on the steering angle of the steering wheel, a current axial force based on the drive current of the steering-side motor that is the driving source of the steering-side actuator, and a lateral force acting on the steered wheels. Lateral G axial force based on acceleration, yaw rate axial force based on the yaw rate of the vehicle, etc. are exemplified, and the steering reaction force is calculated based on the distributed axial force obtained by distributing these.

WO2013/061567

However, in the above-described conventional configuration, if the one axial force becomes an erroneous value, such as when an abnormality occurs in a sensor that detects a value that serves as a basis for calculating one of a plurality of types of axial forces, the distributed axial force is dispensed with. does not accurately reflect the actual road surface reaction force. As a result, an abnormal steering reaction force may be applied, and there is still room for improvement in this respect.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a steering control device capable of suppressing application of an abnormal steering reaction force.

A steering control device that solves the above problems controls a steering device having a structure in which power transmission between a steering section and a steering section that turns steered wheels according to steering input to the steering section is separated. A control unit for controlling the operation of a steering-side motor that provides a steering reaction force, which is a force that resists steering input to the steering unit, is provided, and the control unit controls the steering shaft to which the steerable wheels are connected. A basic reaction force calculation unit that obtains at least two of a plurality of types of axial forces acting on the steered wheels and tire forces acting on the steered wheels to calculate a basic reaction force, and a reaction force component based on the basic reaction force and a target steering angle calculation unit for calculating a target steering angle, which is a target value of the steering angle of the steering wheel connected to the steering unit, for executing angle feedback control for causing the steering angle to follow the target steering angle. A target reaction force torque, which is a target value of the steering reaction force, is calculated based on the basic reaction force calculation unit, and the basic reaction force calculation unit detects that one of the acquired axial forces and the tire forces is abnormal. In this case, the basic reaction force is calculated so that the contribution rate of the abnormal force to the basic reaction force is lower than when any one of the plurality of types of axial force and tire force is normal.

A steering control device that solves the above problems controls a steering device having a structure in which power transmission between a steering section and a steering section that turns steered wheels according to steering input to the steering section is separated. A control unit for controlling the operation of a steering-side motor that provides a steering reaction force, which is a force that resists steering input to the steering unit, is provided, and the control unit controls the steering shaft to which the steerable wheels are connected. A basic reaction force calculation unit that acquires at least two of a plurality of types of axial forces acting on the steered wheels and tire forces acting on the steered wheels and calculates a basic reaction force, and the steering torque applied to the steering unit and the A reaction force component based on the basic reaction force is used to calculate a target reaction force torque, which is a target value of the steering reaction force. When any one of the tire forces is abnormal, the contribution rate of the abnormal force to the basic reaction force becomes lower than when any one of the plurality of types of axial force and the tire force is not abnormal. to calculate the basic reaction force.

A steering control device that solves the above problems controls a steering device having a structure in which power transmission between a steering section and a steering section that turns steered wheels according to steering input to the steering section is separated. A control unit for controlling the operation of a steering-side motor that provides a steering reaction force, which is a force that resists steering input to the steering unit, is provided, and the control unit controls the steering shaft to which the steerable wheels are connected. A basic reaction force calculation unit that obtains at least two of a plurality of types of axial forces acting on the steered wheels and tire forces acting on the steered wheels and calculates a basic reaction force, and uses the reaction force component based on the basic reaction force and calculates a target reaction force torque that is a target value of the steering reaction force, and the basic reaction force calculation unit detects that one of the acquired axial forces and the tire forces is abnormal. In this case, the basic reaction force is calculated so that the contribution rate of the abnormal force to the basic reaction force is lower than when any one of the plurality of types of axial force and tire force is normal.

According to each of the above configurations, since the influence (contribution) of the abnormal axial force or tire force on the value of the basic reaction force is small, the target reaction force torque calculated using the basic reaction force becomes an abnormal value. can be suppressed, and application of an abnormal steering reaction force can be suppressed.

In the steering control device described above, the basic reaction force calculation unit determines, when any one of the acquired axial forces and tire forces is abnormal, that the contribution rate of the abnormal force to the basic reaction force is It is preferable to calculate the basic reaction force to be zero.

According to the above configuration, since the influence of the abnormal axial force or tire force on the value of the basic reaction force is eliminated, it is possible to suitably suppress the target reaction torque calculated based on the basic reaction force from becoming an abnormal value. .

In the steering control device described above, the basic reaction force calculation unit calculates one of the plurality of types of axial force and tire force when any one of the plurality of types of axial force and tire force acquired is abnormal. It is preferable to calculate the basic reaction force so that the contribution rate of forces other than the abnormal force to the basic reaction force is higher than when is not abnormal.

According to the above configuration, it is possible to suppress a change in the magnitude of the steering reaction force before and after an abnormality occurs in any one of a plurality of types of axial force and tire force, thereby reducing the discomfort felt by the driver.

According to the present invention, application of an abnormal steering reaction force can be suppressed.

1 is a schematic configuration diagram of a steer-by-wire steering system according to a first embodiment; FIG. 1 is a block diagram of a steering control device according to a first embodiment; FIG. FIG. 2 is a block diagram of a reaction force component calculator according to the first embodiment; The block diagram of the reaction force component calculating part of 2nd Embodiment. The block diagram of the steering side control part of 3rd Embodiment. The block diagram of the steering control apparatus of 4th Embodiment. The block diagram of the steering control apparatus of 5th Embodiment. FIG. 5 is a schematic configuration diagram of a steer-by-wire steering system according to a modification;

(First embodiment)
A first embodiment of the steering control device will be described below with reference to the drawings.
As shown in FIG. 1, a steer-by-wire steering device 2 to be controlled by a steering control device 1 includes a steering unit 3 steered by a driver and steered wheels 4 according to the steering of the steering unit 3 by the driver. and a steering portion 5 for steering.

The steering unit 3 includes a steering shaft 12 to which a steering wheel 11 is fixed, and a steering-side actuator 13 capable of applying a steering reaction force to the steering shaft 12 . The steering-side actuator 13 includes a steering-side motor 14 that serves as a drive source, and a steering-side reduction gear 15 that decelerates rotation of the steering-side motor 14 and transmits the reduced rotation to the steering shaft 12 . A three-phase brushless motor, for example, is adopted as the steering-side motor 14 of the present embodiment.

The steered portion 5 includes a first pinion shaft 21 as a rotation shaft that can be converted into a steered angle of the steered wheels 4, a rack shaft 22 connected to the first pinion shaft 21, and a rack shaft 22 that can reciprocate. and a rack housing 23 for accommodating them. The first pinion shaft 21 and the rack shaft 22 are arranged with a predetermined crossing angle. A first rack-and-pinion mechanism 24 is constructed by meshing the . The rack shaft 22 is supported by a first rack-and-pinion mechanism 24 so that one axial end thereof can reciprocate. A tie rod 26 is connected to both ends of the rack shaft 22 via a rack end 25 consisting of a ball joint, and the tip of the tie rod 26 is connected to a knuckle (not shown) to which the steered wheels 4 are assembled.

Further, the steering portion 5 is provided with a steering-side actuator 31 that imparts a steering force for steering the steered wheels 4 to the rack shaft 22 via a second pinion shaft 32 . The steering-side actuator 31 includes a steering-side motor 33 that serves as a drive source, and a steering-side reduction gear 34 that decelerates rotation of the steering-side motor 33 and transmits the reduced rotation to the second pinion shaft 32 . The second pinion shaft 32 and the rack shaft 22 are arranged with a predetermined crossing angle. A second rack-and-pinion mechanism 35 is constructed by meshing the . The rack shaft 22 is supported by the second rack-and-pinion mechanism 35 so that the other axial end thereof can reciprocate. A three-phase brushless motor, for example, is adopted as the steering-side motor 33 of the present embodiment.

In the steering apparatus 2 configured as described above, the steering-side actuator 31 rotates the second pinion shaft 32 in response to the driver's steering operation, and the rotation of the rack shaft 22 is caused by the second rack and pinion mechanism 35 . The steered angle of the steered wheels 4 is changed by converting it into an axial movement. At this time, the steering-side actuator 13 applies a steering reaction force to the steering wheel 11 against steering by the driver.

Next, the electrical configuration of this embodiment will be described.
The steering control device 1 is connected to a steering-side actuator 13 (steering-side motor 14) and a steering-side actuator 31 (steering-side motor 33), and controls these operations. The steering control device 1 includes a central processing unit (CPU) and a memory (not shown), and various controls are executed by the CPU executing a program stored in the memory at predetermined calculation cycles.

A torque sensor 41 for detecting a steering torque Th applied to the steering shaft 12 is connected to the steering control device 1 . The torque sensor 41 is provided closer to the steering wheel 11 than the connecting portion of the steering shaft 12 with the steering actuator 13 (steering reduction gear 15). The steering control device 1 is also connected to a left front wheel sensor 42l and a right front wheel sensor 42r provided in a hub unit 42 that rotatably supports the steered wheels 4 via a drive shaft (not shown). A left front wheel sensor 42l and a right front wheel sensor 42r detect the wheel speeds Vl and Vr of the steered wheels 4, respectively. Note that the steering control device 1 of the present embodiment detects an average value of the wheel speeds Vl and Vr as the vehicle speed V. FIG. The steering control device 1 also includes a steering-side rotation sensor 43 for detecting the rotation angle .theta.s of the steering-side motor 14 at a relative angle within a range of 360.degree. A steering-side rotation sensor 44 is connected to detect the rotation angle .theta.t of the steering-side motor 33 as a detection value indicating the steering amount of 5 as a relative angle. The steering control device 1 is also connected to an axial force sensor 45 that acquires a sensor axial force Fse, which is a detected value of the axial force acting on the rack shaft 22 . As the axial force sensor 45, for example, one that detects the axial force based on the pressure change according to the stroke of the rack shaft 22 can be used. The steering control device 1 acquires the sensor axial force Fse in the dimension of torque (N·m). The steering torque Th and the rotation angles θs and θt are given as positive values when steering in one direction (right in this embodiment) and negative values when steering in the other direction (left in this embodiment). To detect. Then, the steering control device 1 controls the operations of the steering-side motor 14 and the turning-side motor 33 based on these various state quantities.

The configuration of the steering control device 1 will be described in detail below.
As shown in FIG. 2, the steering control device 1 includes a steering-side control unit 51 as a control unit that outputs a steering-side motor control signal Ms, and supplies driving power to the steering-side motor 14 based on the steering-side motor control signal Ms. and a steering-side drive circuit 52 for supplying power. The steering-side control unit 51 detects phase current values Ius, Ivs, and Iws of the steering-side motor 14 flowing through connection lines 53 between the steering-side drive circuit 52 and the motor coils of the respective phases of the steering-side motor 14. A current sensor 54 is connected. In addition, in FIG. 2, for convenience of explanation, the connection lines 53 of each phase and the current sensors 54 of each phase are collectively illustrated as one.

The steering control device 1 also includes a steering-side control unit 55 that outputs a steering-side motor control signal Mt, and a steering-side motor 33 that supplies drive power to the steering-side motor 33 based on the steering-side motor control signal Mt. and a drive circuit 56 . The steering-side control unit 55 stores current values Iut, Ivt, and current values Iut, Ivt, and Iut of each phase of the steering-side motor 33 flowing through a connection line 57 between the steering-side drive circuit 56 and the motor coils of the respective phases of the steering-side motor 33 . A current sensor 58 is connected to detect Iwt. In addition, in FIG. 2, for convenience of explanation, the connection lines 57 of each phase and the current sensors 58 of each phase are shown together as one. A well-known PWM inverter having a plurality of switching elements (for example, FETs, etc.) is adopted for each of the steering-side drive circuit 52 and the turning-side drive circuit 56 of the present embodiment. The steering-side motor control signal Ms and the turning-side motor control signal Mt are gate on/off signals that define the on/off state of each switching element.

The steering control device 1 outputs the steering-side motor control signal Ms and the steering-side motor control signal Mt to the steering-side drive circuit 52 and the steering-side drive circuit 56, respectively, thereby controlling the steering-side motor 14 and the steering-side motor 33. , respectively. Thereby, the steering control device 1 controls the operations of the steering-side actuator 13 and the turning-side actuator 31 .

First, the configuration of the steering-side control section 51 will be described.
The steering-side control unit 51 executes each arithmetic processing shown in each control block below at each predetermined arithmetic cycle to calculate the steering-side motor control signal Ms. The steering-side control unit 51 receives the vehicle speed V, the steering torque Th, the rotation angle θs, the sensor axial force Fse, the phase current values Ius, Ivs, and Iws, and the q-axis current which is the driving current of the steering-side motor 33 described later. A value Iqt is entered. Then, the steering-side control section 51 calculates and outputs a steering-side motor control signal Ms based on these state quantities.

Specifically, the steering-side controller 51 includes a steering angle calculator 61 that calculates the steering angle θh of the steering wheel 11 based on the rotation angle θs of the steering-side motor 14 . The steering-side control unit 51 also includes an input torque basic component calculation unit 62 that calculates an input torque basic component Tb* that is a force that rotates the steering wheel 11 in the steering direction of the driver, and an input torque basic component calculation unit 62 that calculates the input torque basic component Tb*, which is a force that rotates the steering wheel 11 in the steering direction of the driver. and a reaction force component calculation unit 63 for calculating a reaction force component Fir, which is a force resisting the rotation of the . The steering-side control unit 51 also includes a target steering angle calculator 64 that calculates a target steering angle θh* based on the steering torque Th, the input torque basic component Tb*, the reaction force component Fir, and the vehicle speed V. Further, the steering-side control unit 51 includes a target reaction torque calculation unit 65 that calculates a target reaction torque Ts* based on the steering angle θh and the target steering angle θh*, and a steering-side control unit 65 that calculates a target reaction torque Ts* based on the target reaction torque Ts*. A steering-side motor control signal calculator 66 for calculating the motor control signal Ms is provided.

The steering angle calculator 61 obtains the input rotation angle θs by converting it into an absolute angle exceeding 360°, for example, by counting the number of rotations of the steering-side motor 14 from the steering neutral position. Then, the steering angle calculator 61 calculates the steering angle θh by multiplying the absolute angle-converted rotation angle by a conversion coefficient Ks based on the rotation speed ratio of the steering-side reduction gear 15 .

The steering torque Th is input to the input torque basic component calculator 62 . The input torque basic component calculator 62 calculates an input torque basic component (reaction force basic component) Tb* having a larger absolute value as the absolute value of the steering torque Th increases. The input torque basic component Tb* is input to the target steering angle calculator 64 and the target reaction force torque calculator 65 .

In addition to the steering torque Th, the vehicle speed V, and the input torque basic component Tb*, the reaction force component Fir calculated by the reaction force component calculation unit 63 described later is input to the target steering angle calculation unit 64 . The target steering angle calculator 64 calculates a model (steering model ) to calculate the target steering angle θh*.

Tin*=C·θh*′+J·θh*'' (1)
This model formula expresses the torque and rotation It defines and expresses the relationship with the angle. This model formula is expressed using a viscosity coefficient C that models the friction and the like of the steering device 2 and an inertia coefficient J that models the inertia of the steering device 2 . Note that the viscosity coefficient C and the inertia coefficient J are variably set according to the vehicle speed V. FIG. The target steering angle θh* thus calculated using the model formula is output to the reaction force component calculation section 63 in addition to the subtractor 67 and steering side control section 55 .

In addition to the input torque basic component Tb*, the target reaction force torque calculator 65 receives an angle deviation Δθs obtained by subtracting the steering angle θh from the target steering angle θh* in a subtractor 67 . Based on the angular deviation Δθs, the target reaction force torque calculation unit 65 provides a basis for the steering reaction force applied by the steering-side motor 14 as a control amount for feedback-controlling the steering angle θh to the target steering angle θh*. A target reaction torque Ts* is calculated by calculating a reaction torque and adding an input torque basic component Tb* to the basic reaction torque. Specifically, the target reaction torque calculator 65 calculates the sum of the output values of the proportional element, the integral element, and the differential element to which the angular deviation Δθs is input, as the basic reaction torque.

In addition to the target reaction torque Ts*, the rotation angle θs and the phase current values Ius, Ivs, and Iws are input to the steering-side motor control signal calculator 66 . Then, the steering-side motor control signal calculator 66 calculates a q-axis target current value Iqs* on the q-axis in the d/q coordinate system based on the target reaction torque Ts*. In this embodiment, the d-axis target current value Ids* on the d-axis is basically set to zero.

The steering-side motor control signal calculator 66 calculates the steering-side motor control signal Ms by executing current feedback control in the d/q coordinate system. Specifically, the steering-side motor control signal calculation unit 66 maps the phase current values Ius, Ivs, and Iws onto the d/q coordinates based on the rotation angle θs, so that the steering-side motor control signal in the d/q coordinate system A d-axis current value Ids and a q-axis current value Iqs, which are actual current values of 14, are calculated. Subsequently, the steering-side motor control signal calculator 66 causes the d-axis current value Ids to follow the d-axis target current value Ids* and the q-axis current value Iqs to follow the q-axis target current value Iqs*. A voltage command value is calculated based on each current deviation on the d-axis and the q-axis. Then, the steering-side motor control signal calculation unit 66 calculates a steering-side motor control signal Ms having a duty ratio based on the voltage command value, and outputs it to the steering-side drive circuit 52 . As a result, the steering control device 1 outputs the drive power corresponding to the steering motor control signal Ms to the steering motor 14 to control its operation.

Next, the steering-side control section 55 will be described.
The steering-side control unit 55 executes each arithmetic processing shown in each control block below at each predetermined computation cycle to calculate a steering-side motor control signal Mt. The rotation angle θt, the target steering angle θh*, and the phase current values Iut, Ivt, and Iwt of the steering-side motor 33 are input to the steering-side control unit 55 . Then, the steering-side control section 55 calculates and outputs a steering-side motor control signal Mt based on these state quantities.

Specifically, the steered-side control unit 55 calculates a steered corresponding angle θp corresponding to the rotation angle (pinion angle) of the first pinion shaft 21 , which is a rotation axis convertible to the steered angle of the steered wheels 4 . A rudder correspondence angle calculator 71 is provided. Further, the steering-side control unit 55 includes a target steering torque calculation unit 72 that calculates a target steering torque Tt* based on the steering corresponding angle θp and the target steering angle θh*, and a target steering torque calculation unit 72 that calculates a target steering torque Tt* based on the target steering torque Tt*. and a steering-side motor control signal calculator 73 for calculating a steering-side motor control signal Mt. In the steering device 2 of the present embodiment, the steering angle ratio, which is the ratio between the steering angle θh and the steering corresponding angle θp, is set constant, and the target steering corresponding angle is equal to the target steering angle θh*. .

The steering corresponding angle calculator 71 obtains the input rotation angle θt by converting it into an absolute angle, for example, by counting the number of rotations of the steering side motor 33 from the neutral position where the vehicle travels straight. Then, the steered corresponding angle calculation unit 71 converts the rotation angle converted to the absolute angle into a conversion based on the rotation speed ratio of the steered side reduction gear 34 and the rotation speed ratio of the first and second rack and pinion mechanisms 24 and 35. Multiplying the coefficient Kt, the corresponding steering angle θp is calculated. That is, the steered corresponding angle θp corresponds to the steering angle θh of the steering wheel 11 assuming that the first pinion shaft 21 is connected to the steering shaft 12 .

The target steering torque calculator 72 receives an angle deviation Δθp obtained by subtracting the steering corresponding angle θp from the target steering angle θh* (target steering corresponding angle) in a subtractor 74 . Based on the angular deviation Δθp, the target steering torque calculation unit 72 calculates the steering force applied by the steering-side motor 33 as a control amount for feedback-controlling the steering corresponding angle θp to the target steering angle θh*. A target steering torque Tt*, which is a target value, is calculated. Specifically, the target turning torque calculation unit 72 calculates the sum of the output values of the proportional element, the integral element, and the differential element to which the angular deviation Δθp is input, as the target turning torque Tt*.

In addition to the target steering torque Tt*, the rotation angle θt and the phase current values Iut, Ivt, and Iwt are input to the steering-side motor control signal calculator 73 . Then, the steering-side motor control signal calculator 73 calculates a q-axis target current value Iqt* on the q-axis in the d/q coordinate system based on the target steering torque Tt*. In this embodiment, the d-axis target current value Idt* on the d-axis is basically set to zero.

The steering-side motor control signal calculator 73 calculates a steering-side motor control signal Mt by executing current feedback control in the d/q coordinate system. Specifically, the steering-side motor control signal calculation section 73 maps the phase current values Iut, Ivt, and Iwt onto the d/q coordinates based on the rotation angle θt, thereby obtaining the steering angle in the d/q coordinate system. A d-axis current value Idt and a q-axis current value Iqt, which are actual current values of the side motor 33, are calculated. Subsequently, the steering-side motor control signal calculator 73 causes the d-axis current value Idt to follow the d-axis target current value Idt* and the q-axis current value Iqt to follow the q-axis target current value Iqt*. , the voltage command value is calculated based on the current deviation on the d-axis and the q-axis. Then, the steering-side motor control signal calculation unit 73 calculates a steering-side motor control signal Mt having a duty ratio based on the voltage command value, and outputs it to the steering-side drive circuit 56 . As a result, the steering control device 1 outputs drive power to the steering motor 33 according to the steering motor control signal Mt to control its operation. Note that the q-axis current value Iqt calculated in the process of calculating the steering-side motor control signal Mt is output to the reaction force component calculator 63 .

Next, the configuration of the reaction force component calculator 63 will be described.
The vehicle speed V, the sensor axial force Fse, the q-axis current value Iqt of the steering-side motor 33, and the target steering angle θh* are input to the reaction force component calculator 63 . The reaction force component calculator 63 calculates a reaction force component Fir corresponding to the axial force acting on the rack shaft 22 based on these state quantities, and outputs the calculated reaction force component Fir to the target steering angle calculator 64 .

As shown in FIG. 3, the reaction force component calculation unit 63 includes an abnormality determination unit 81 that determines whether each state quantity (signal) to be input is abnormal, and a reaction force component Fir based on each state quantity. and a basic reaction force calculator 82 for calculating the basic reaction force.

The vehicle speed V, the sensor axial force Fse, the q-axis current value Iqt, and the target steering angle θh* are input to the abnormality determination unit 81 . The abnormality determination unit 81 determines that there is an abnormality when, for example, each state quantity becomes an unacceptable value, or when the amount of change from the previous value exceeds a preset threshold value. It is determined whether each state quantity is abnormal. Then, the abnormality determination unit 81 uses the input vehicle speed V, the sensor axial force Fse, the q-axis current value Iqt, and the target steering angle θh* together with the determination signal Sde indicating the determination result of the abnormality determination as they are to the basic reaction force calculation unit 82 . output to

The basic reaction force calculator 82 includes a current axial force calculator 83 that calculates a current axial force (road surface axial force) Fer and an angular axial force calculator 84 that calculates an angular axial force (ideal axial force) Fib. there is The current axial force Fer and the angular axial force Fib are calculated in terms of torque (N·m). Further, the basic reaction force calculation unit 82 calculates the current axial force Fer, the angular axial force Fib, and the sensor axial force so that the axial force applied to the steered wheels 4 from the road surface (road surface information transmitted from the road surface) is reflected. A distributed axial force calculation unit 85 is provided for calculating a distributed axial force obtained by distributing the force Fse at a predetermined ratio as a reaction force component Fir (basic reaction force).

A q-axis current value Iqt of the steering-side motor 33 is input to the current axial force calculation unit 83 . A current axial force calculator 83 converts the current axial force Fer, which is an estimated value of the axial force acting on the steered wheels 4 (transmission force transmitted to the steered wheels 4) reflecting the road surface information, into the q-axis current value Iqt. Calculate based on Specifically, the current axial force calculation unit 83 calculates a q-axis The calculation is performed so that the absolute value of the current axial force Fer increases as the absolute value of the current value Iqt increases. The current axial force Fer calculated in this manner is output to the distributed axial force calculation unit 85 .

The target steering angle θh* (target steering corresponding angle) and the vehicle speed V are input to the angular axial force calculator 84 . The angular axial force calculator 84 converts the angular axial force Fib, which is an ideal value of the axial force acting on the steered wheels 4 (the transmission force transmitted to the steered wheels 4) and does not reflect the road surface information, into the target steering angle θh*. calculated based on Specifically, the angular axial force calculation unit 84 calculates so that the absolute value of the angular axial force Fib increases as the absolute value of the target steering angle θh* increases. Further, the angular axial force calculation unit 84 calculates so that the absolute value of the angular axial force Fib increases as the vehicle speed V increases. The angular axial force Fib calculated in this manner is output to the distributed axial force calculation unit 85 .

In addition to the determination signal Sde, the current axial force Fer and the angular axial force Fib, the sensor axial force Fse is input to the distributed axial force calculation unit 85 . The distribution axial force calculator 85 includes a current distribution gain Ger indicating the distribution ratio of the current axial force Fer, an angle distribution gain Gib indicating the distribution ratio of the angular axial force Fib, and a sensor distribution gain indicating the distribution ratio of the sensor axial force Fse. Gse is preset by experiment or the like. Then, the distributed axial force calculator 85 multiplies the angular axial force Fib by the angular distribution gain Gib, the current axial force Fer by the current distribution gain Ger, and the sensor axial force Fse by the sensor distribution gain Gse. The reaction force component Fir is calculated by adding the values obtained. That is, the basic reaction force calculator 82 of the present embodiment acquires three axial forces, ie, the current axial force Fer, the angular axial force Fib, and the sensor axial force Fse, and based on these three axial forces, the reaction force component Fir ( basic reaction force).

Here, each of the distribution gains Ger, Gib, and Gse is set to a different value according to the determination result indicated by the determination signal Sde. Specifically, when there is an abnormality in the acquired state quantity, the distribution gain multiplied by the axial force based on the state quantity with the abnormality becomes smaller than when there is no abnormality, and each state quantity without abnormality It is set so that the distribution gain multiplied by the axial force based on is large. That is, the basic reaction force calculation unit 82 of the present embodiment determines that the axial force is abnormal when the state quantity for calculating the axial force is abnormal. Then, each of the distribution gains Ger, Gib, and Gse, when there is an abnormality in each acquired state quantity, the contribution ratio of the axial force (abnormal axial force) based on the state quantity with the abnormality to the reaction force component Fir is It is set so that the rate of contribution of the axial force (normal axial force) based on each normal state quantity to the reaction force component Fir increases as the value decreases.

As an example, the current distribution gain Ger is "0.3" when each state quantity is normal, "0" when the q-axis current value Iqt is abnormal, and other than the q-axis current value Iqt (target steering If at least one of the angle θh*, the vehicle speed V, and the sensor axial force Fse) is abnormal, it is set to "0.45". The angle distribution gain Gib is "0.45" when each state quantity is normal, "0" when at least one of the target steering angle θh* and the vehicle speed V is abnormal, and the target steering angle θh * and the vehicle speed V (at least one of the q-axis current value Iqt and the sensor axial force Fse) is abnormal, it is set to "0.6". Further, the sensor distribution gain Gse is "0.7" when each state quantity is normal, "0" when the sensor axial force Fse is abnormal, and other than the sensor axial force Fse (target steering angle θh* , at least one of the vehicle speed V and the q-axis current value Iqt) is set to "0.9". The values of the distribution gains Ger, Gib, and Gse can be appropriately changed, and the sum of these may be set to "1", or may be set to be larger or smaller than "1". good.

Next, the operation and effects of this embodiment will be described.
(1) If any of the current axial force Fer, the angular axial force Fib, and the sensor axial force Fse is abnormal, the basic reaction force calculator 82 calculates distribution gains Ger and Gib by which the abnormal axial force is multiplied. , Gse are set to zero, the contribution ratio of the abnormal axial force to the reaction force component Fir (basic reaction force) is set to zero. Specifically, when there is no abnormality in the current axial force Fer, the angular axial force Fib, and the sensor axial force Fse, the basic reaction force calculation unit 82 sets the current axial force Fer to 30% and the angular axial force Fib to 45%. , the sensor axial force Fse is distributed at a rate of 70% to calculate the reaction force component Fir. Here, for example, assuming a case where the value of the sensor axial force Fse is abnormal, the basic reaction force calculation unit 82 sets the current axial force Fer to 45%, the angular axial force Fib to 60%, and the sensor axial force Fse to 0%. , and calculate the reaction force component Fir. This eliminates the influence (contribution) of the abnormal axial force on the value of the reaction force component Fir, so that the target reaction force torque Ts* calculated using the reaction force component Fir is preferably prevented from becoming an abnormal value. and the application of an abnormal steering reaction force can be suitably suppressed.

(2) When any one of the current axial force Fer, the angular axial force Fib, and the sensor axial force Fse is abnormal, the basic reaction force calculation unit 82 multiplies the axial force other than the abnormal axial force. By increasing Ger, Gib, and Gse, the contribution rate of the axial force other than the abnormal axial force to the reaction force component Fir is increased. As a result, it is possible to suppress the change in the magnitude of the steering reaction force before and after an abnormality occurs in any of the current axial force Fer, the angular axial force Fib, and the sensor axial force Fse, thereby reducing the discomfort felt by the driver. can.

(Second embodiment)
Next, a second embodiment of the steering control device will be described with reference to the drawings. For convenience of explanation, the same components as those of the first embodiment are denoted by the same reference numerals, and the explanation thereof is omitted.

As shown in FIG. 4, the target steering angle θh*, vehicle speed V, q-axis current value Iqt, and tire force Ft are input to the reaction force component calculator 63 of the present embodiment, but the sensor axial force Fse is not input. The tire force Ft is the load in the longitudinal direction of the vehicle (x direction), the load in the lateral direction of the vehicle (y direction), the load in the vertical direction of the vehicle (z direction), the load detected by the hub unit 42 (see FIG. 1), and the load in the vertical direction of the vehicle (z direction). It is a value (unit: Newton) based on at least one of the moment about the axis, the moment about the y-axis, and the moment about the z-axis.

The vehicle speed V, the q-axis current value Iqt, the target steering angle θh*, and the tire force Ft are input to the abnormality determination unit 81 of this embodiment. Then, the abnormality determination unit 81 performs abnormality determination of each state quantity in the same manner as in the first embodiment. θh* and the tire force Ft are directly output to the basic reaction force calculator 82 .

The basic reaction force calculation unit 82 of this embodiment includes a torque conversion unit 91 and an output switching unit 92 in addition to the current axial force calculation unit 83 , the angular axial force calculation unit 84 and the distribution axial force calculation unit 85 . The current axial force calculation unit 83 and the angular axial force calculation unit 84 calculate the current axial force Fer and the angular axial force Fib, respectively, and output them to the distribution axial force calculation unit 85 in the same manner as in the first embodiment.

The distributed axial force calculation unit 85 includes a distribution gain calculation unit 101 that calculates a current distribution gain Ger and an angle distribution gain Gib based on the vehicle speed V. FIG. The distribution gain calculator 101 of this embodiment has a map that defines the relationship between the vehicle speed V and the distribution gains Ger and Gib. do. The current distribution gain Ger has a larger value when the vehicle speed V is high than when it is low, and the angle distribution gain Gib has a smaller value when the vehicle speed V is high than when it is low. In this embodiment, the values are set so that the sum of the distributed gains Ger and Gib is "1". The current distribution gain Ger calculated in this way is output to the multiplier 102, and the angle distribution gain Gib is output to the multiplier 103. FIG.

The current axial force Fer is input to the multiplier 102 and the angular axial force Fib is input to the multiplier 103 . In the distributed axial force calculation unit 85, the multiplier 102 multiplies the current axial force Fer by the current distribution gain Ger, the multiplier 103 multiplies the angular axial force Fib by the angular distribution gain Gib, and the adder 104 multiplies the angular axial force Fib by the angular distribution gain Gib. are added together to calculate the distributed axial force Fd. The distributed axial force Fd calculated in this manner is output to the output switching section 92 .

A tire force Ft is input to the torque conversion unit 91 . The torque conversion unit 91 calculates the tire torque Tt around the first pinion shaft 21 by multiplying the tire force Ft by a conversion coefficient Kp based on the rotational speed ratio of the first rack-and-pinion mechanism 24 . The tire torque Tt calculated in this manner is output to the output switching section 92 .

The determination signal Sde is input to the output switching unit 92 in addition to the distributed axial force Fd and the tire torque Tt. Based on the determination signal Sde, the output switching unit 92 outputs the distributed axial force Fd as the reaction force component Fir when there is no abnormality in each state quantity that is the basis of the distributed axial force Fd. If at least one is abnormal, the tire torque Tt is output as the reaction force component Fir. That is, the basic reaction force calculator 82 of the present embodiment obtains three forces, the current axial force Fer and the angular axial force Fib, and the tire force Ft, and distributes the distribution axis based on the current axial force Fer and the angular axial force Fib. The force Fd or the tire torque Tt based on the tire force Ft is output as the reaction force component Fir. Further, the basic reaction force calculation unit 82 reduces the contribution ratio of the abnormal axial force to the reaction force component Fir by switching to the tire torque Tt when there is an abnormality in each state quantity that is the basis of the distributed axial force Fd. (zero) to calculate the reaction force component Fir.

As described above, the present embodiment has the same action and effect as the action and effect of (1) of the first embodiment.
(Third embodiment)
Next, a third embodiment of the steering control device will be described with reference to the drawings. For convenience of explanation, the same components as those of the first embodiment are denoted by the same reference numerals, and the explanation thereof is omitted.

As shown in FIG. 5, the input torque basic component calculation section 62 of the present embodiment is a torque command value Th* which is a target value of the steering torque Th to be input by the driver with respect to the driving torque Tc. It has a value calculation section 111 and a torque feedback control section (hereinafter referred to as torque F/B control section) 112 that performs torque feedback calculation.

Specifically, the drive torque Tc obtained by adding the input torque basic component Tb* to the steering torque Th in the adder 113 is input to the torque command value calculation unit 111 . The torque command value calculation unit 111 calculates a torque command value Th* that becomes a larger absolute value as the absolute value of the drive torque Tc increases.

Torque F/B control unit 112 receives torque deviation ΔT obtained by subtracting torque command value Th* from steering torque Th in subtractor 114 . Based on the torque deviation ΔT, the torque F/B control unit 112 calculates an input torque basic component Tb* as a control amount for feedback-controlling the steering torque Th to the torque command value Th*. Specifically, the torque F/B control unit 112 calculates the sum of the output values of the proportional element, the integral element, and the differential element to which the torque deviation ΔT is input, as the input torque basic component Tb*.

The input torque basic component Tb* calculated in this manner is output to the target steering angle calculation section 64 and the target reaction force torque calculation section 65, as well as to the adder 113, as in the first embodiment. Accordingly, the target steering angle θh* is calculated by the target steering angle calculator 64, and the target reaction torque Ts* is calculated by the target reaction torque calculator 65, as in the first embodiment.

As described above, the present embodiment has the same actions and effects as the actions and effects (1) and (2) of the first embodiment.
(Fourth embodiment)
Next, a fourth embodiment of the steering control device will be described with reference to the drawings. For convenience of explanation, the same components as those of the first embodiment are denoted by the same reference numerals, and the explanation thereof is omitted.

As shown in FIG. 6, the steering-side control unit 51 of the present embodiment calculates a target steering response angle θp*, which is a target value of the steering response angle θp that can be converted into the steering angle of the steerable wheels 4. The steering corresponding angle calculator 121 is provided, and the target steering angle calculator 64 is not provided.

The steering-side control unit 51 includes an adder 122 to which the input torque basic component Tb* is input together with the steering torque Th. The steering-side control unit 51 also includes a subtractor 123 to which the reaction force component Fir is input together with the driving torque Tc. Calculate. The input torque Tin* calculated in this manner is output to the target reaction force torque calculation section 65 and the target steering corresponding angle calculation section 121 . The target reaction force torque calculation unit 65 calculates a target reaction force torque Ts*, which is a target value of the steering reaction force applied by the steering-side motor 14, based on the input torque Tin*. Specifically, the target reaction torque calculation unit 65 calculates the target reaction torque Ts* having a larger absolute value as the input torque Tin* increases.

The input torque Tin* and the vehicle speed V are input to the target steering corresponding angle calculator 121 . The target steering corresponding angle calculation unit 121 calculates the target steering corresponding angle θp* by the same calculation processing as the calculation processing when the target steering angle calculation unit 64 of the first embodiment calculates the target steering angle θh*. do. The target steering corresponding angle θp* calculated in this way is the same value as the target steering angle θh* of the first embodiment, and is output to the steering side control section 55 and the reaction force component calculation section 63. .

As described above, the present embodiment has the same actions and effects as the actions and effects (1) and (2) of the first embodiment.
(Fifth embodiment)
Next, a fifth embodiment of the steering control device will be described with reference to the drawings. For convenience of explanation, the same components as those of the fourth embodiment are denoted by the same reference numerals, and the explanation thereof is omitted.

As shown in FIG. 7, the reaction force component Fir and the vehicle speed V are input to the target reaction force torque calculator 65 of the present embodiment. Then, the target reaction torque calculation unit 65 calculates the target reaction torque Ts* having a larger absolute value as the absolute value of the reaction force component Fir increases and as the vehicle speed V increases.

As described above, the present embodiment has the same actions and effects as the actions and effects (1) and (2) of the first embodiment.
This embodiment can be implemented with the following modifications. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

・In the first, third to fifth embodiments, the reaction force component Fir is calculated based on the current axial force Fer, the angular axial force Fib, and the sensor axial force Fse. Additionally or alternatively, the reaction force component Fir may be calculated using an axial force estimated based on other state quantities. Such other axial force includes, for example, vehicle state quantity axial force calculated based on yaw rate and lateral acceleration, tire axial force calculated based on tire force Ft, and the like. Similarly, in the above-described second embodiment, the distributed axial force Fd may be calculated using other state quantities.

- In the above-described second embodiment, the distributed axial force Fd or the tire torque Tt is output as the reaction force component Fir according to the result of the abnormality determination. However, the configuration for switching the output according to the determination result is not limited to this. Either one may be output, and the other may be output when the state quantity that is the basis of the one is abnormal.

・In the first, third to fifth embodiments, if any of the current axial force Fer, the angular axial force Fib, and the sensor axial force Fse is abnormal, the distribution gain Ger to be multiplied by the abnormal axial force , Gib, and Gse are set to zero, but the distribution gains Ger, Gib, and Gse may be set to values greater than zero as long as they are smaller than the normal case. As a result, the influence of the abnormal axial force on the value of the reaction force component Fir is reduced, so that the target reaction force torque Ts* calculated using the reaction force component Fir can be prevented from becoming an abnormal value.

・In the first, third to fifth embodiments, if any of the current axial force Fer, the angular axial force Fib, and the sensor axial force Fse is abnormal, the axial force other than the abnormal axial force is multiplied. Although the distribution gains Ger, Gib and Gse to be applied are increased, the present invention is not limited to this.

In each of the above-described embodiments, the abnormality determination unit 81 determines abnormality of the value of each state quantity itself, and determines that the axial force is abnormal when there is abnormality in the state quantity for calculating the axial force. However, not limited to this, in addition to or instead of the same determination, for example, the abnormality of the arithmetic processing (for example, the arithmetic processing of the current axial force calculation unit 83 that calculates the current axial force Fer based on the q-axis current value Iqt) is judged. However, whether or not the axial force is abnormal may be determined based on the same determination result, and the method for determining abnormality can be changed as appropriate.

- In each of the above-described embodiments, the current axial force Fer is calculated based on the q-axis current value Iqt.
・In each of the above embodiments, the angular axial force Fib is calculated based on the target steering angle θh* (target steering corresponding angle) and the vehicle speed V. ) only. Further, calculation may be performed based on not only the target steering angle θh*, but also the steering angle θh or the steering corresponding angle θp. Furthermore, other methods such as adding other parameters such as the steering torque Th and the vehicle speed V may be used.

- In the above-described second embodiment, the distributed axial force calculation section 85 may calculate the distributed gains Ger and Gib in consideration of parameters other than the vehicle speed V. For example, in a vehicle in which a drive mode indicating the setting state of a control pattern of an in-vehicle engine or the like can be selected from among a plurality of drive modes, the drive mode may be used as a parameter for setting the distribution gains Ger and Gib. In this case, it is possible to employ a configuration in which the distributed axial force calculation unit 85 is provided with a plurality of maps showing different tendencies with respect to the vehicle speed V for each drive mode, and the distributed gains Ger and Gib are calculated by referring to the maps.

- In the above-described fourth and fifth embodiments, the target steering corresponding angle θp* is calculated based on the input torque Tin*. good too.

- In each of the above-described embodiments, the reaction force component calculation unit 63 may calculate a value in consideration of a reaction force other than the distributed axial force Fd or the tire torque Tt as the reaction force component Fir. As such a reaction force, for example, when the absolute value of the steering angle θh of the steering wheel 11 approaches the steering angle threshold value, an end reaction force, which is a reaction force against further cutting steering, can be employed. Note that the steering angle threshold value is, for example, a virtual rack end set on the neutral position side of the mechanical rack end position where the axial movement of the rack shaft 22 is restricted when the rack end 25 comes into contact with the rack housing 23 . A steering corresponding angle θp at a position can be used. Further, the steering angle θh at the rotation end position of the steering wheel 11 can be used as the steering angle threshold.

- Although the steering angle ratio between the steering angle θh and the corresponding steering angle θp is constant in each of the above embodiments, the ratio is not limited to this and may be variable according to the vehicle speed or the like. In this case, the target steering angle θh* and the target steering corresponding angle are different values.

In each of the above-described embodiments, the target steering angle calculation unit 64 uses a model formula modeled by adding a so-called spring term using the spring coefficient K determined by the specifications of the suspension, wheel alignment, etc., to achieve the target steering angle. An angle θh* may be calculated.

・In the first to third embodiments, the target reaction torque calculation unit 65 calculates the target reaction torque Ts* by adding the input torque basic component Tb* to the basic reaction torque. For example, the basic reaction torque may be directly calculated as the target reaction torque Ts* without adding the input torque basic component Tb*.

- In each of the above embodiments, instead of the first rack and pinion mechanism 24, the rack shaft 22 may be supported by, for example, a bush.
In each of the above-described embodiments, as the steering-side actuator 31, for example, the steering-side motor 33 is arranged coaxially with the rack shaft 22, or the steering-side motor 33 is arranged parallel to the rack shaft 22. may be used.

In each of the above embodiments, the steering device 2 to be controlled by the steering control device 1 is a linkless steer-by-wire steering device in which the steering section 3 and the steering section 5 are mechanically separated. Alternatively, a steer-by-wire steering system may be used in which power transmission between the steering portion 3 and the steering portion 5 can be switched on and off by a clutch.

For example, in the example shown in FIG. 8 , a clutch 201 is provided between the steering section 3 and the steering section 5 . The clutch 201 is connected to the steering shaft 12 via an input-side intermediate shaft 202 fixed to its input-side element, and connected to the first pinion shaft 21 via an output-side intermediate shaft 203 fixed to its output-side element. connected to When the clutch 201 is released by the control signal from the steering control device 1, the steering device 2 enters the steer-by-wire mode, and when the clutch 201 enters the engaged state, the steering device 2 enters the electric power steering mode. .

Next, technical ideas that can be grasped from the above embodiments and modifications will be added below.
(b) The steering control device, wherein the basic reaction force calculation unit calculates the distributed axial force or the tire force obtained by adding up the plurality of types of axial forces at an individually set distribution ratio as the basic reaction force.

DESCRIPTION OF SYMBOLS 1... Steering control apparatus 2... Steering apparatus 3... Steering part 4... Steering wheel 5... Steering part 11... Steering wheel 12... Steering shaft 14... Steering side motor 22... Rack shaft (steering axis), 51... Steering-side control section (control section), 63... Reaction component calculation section, 64... Target steering angle calculation section, 65... Target reaction force torque calculation section, 81... Abnormality determination section, 82... Basic reaction force Calculation unit 83 Current axial force calculation unit 84 Angle axial force calculation unit 85 Distribution axial force calculation unit 91 Torque conversion unit 92 Output switching unit 101 Distribution gain calculation unit Fd Distribution axis Force, Ft...Tire force, Fer...Current axial force, Fib...Angular axial force, Fir...Reaction force component (basic reaction force), Fse...Sensor axial force, Ger...Current distribution gain, Gib...Angle distribution gain, Gse... Sensor distribution gain Sde... Judgment signal Th... Steering torque Ts*... Target reaction torque Th*... Torque command value Tt... Tire torque ?h... Steering angle ?h*... Target steering angle.

Claims (5)

A steering device having a structure in which power transmission between a steering unit and a steering unit that turns steerable wheels according to steering input to the steering unit is separated is controlled,
a control unit for controlling the operation of a steering-side motor that provides a steering reaction force that is a force that resists steering input to the steering unit;
The control unit
a basic reaction force calculation unit that acquires at least two of a plurality of types of axial forces acting on a steered shaft to which the steered wheels are connected and tire forces acting on the steered wheels to calculate a basic reaction force;
a target steering angle calculation unit that calculates a target steering angle, which is a target value of the steering angle of the steering wheel connected to the steering unit, using a reaction force component based on the basic reaction force;
A target reaction force torque, which is a target value of the steering reaction force, is calculated based on execution of angle feedback control for causing the steering angle to follow the target steering angle,
The basic reaction force calculation unit, when any one of the plurality of types of axial force and the tire force acquired is abnormal, is compared to a case where any of the plurality of types of axial force and the tire force is not abnormal. , a steering control device that calculates the basic reaction force so that the contribution rate of the abnormal force to the basic reaction force is low; A steering device having a structure in which power transmission between a steering unit and a steering unit that turns steerable wheels according to steering input to the steering unit is separated is controlled,
a control unit for controlling the operation of a steering-side motor that provides a steering reaction force that is a force that resists steering input to the steering unit;
The control unit
a basic reaction force calculation unit that acquires at least two of a plurality of types of axial forces acting on a steered shaft to which the steered wheels are connected and tire forces acting on the steered wheels and calculates a basic reaction force;
A target reaction force torque, which is a target value of the steering reaction force, is calculated using a reaction force component based on the steering torque applied to the steering unit and the basic reaction force,
The basic reaction force calculation unit, when any one of the plurality of types of axial force and the tire force acquired is abnormal, is compared to a case where any of the plurality of types of axial force and the tire force is not abnormal. , a steering control device that calculates the basic reaction force so that the contribution rate of the abnormal force to the basic reaction force is low; A steering device having a structure in which power transmission between a steering unit and a steering unit that turns steerable wheels according to steering input to the steering unit is separated is controlled,
a control unit for controlling the operation of a steering-side motor that provides a steering reaction force that is a force that resists steering input to the steering unit;
The control unit
a basic reaction force calculation unit that acquires at least two of a plurality of types of axial forces acting on a steered shaft to which the steered wheels are connected and tire forces acting on the steered wheels and calculates a basic reaction force;
A target reaction force torque, which is a target value of the steering reaction force, is calculated using a reaction force component based on the basic reaction force,
The basic reaction force calculation unit, when any one of the plurality of types of axial force and the tire force acquired is abnormal, is compared to a case where any of the plurality of types of axial force and the tire force is not abnormal. , a steering control device that calculates the basic reaction force so that the contribution rate of the abnormal force to the basic reaction force is low; In the steering control device according to any one of claims 1 to 3,
The basic reaction force calculation unit, when any one of the acquired plural types of axial force and the tire force is abnormal, calculates the basic reaction force so that the contribution rate of the abnormal force to the basic reaction force becomes zero. A steering control device that calculates the basic reaction force. In the steering control device according to any one of claims 1 to 4,
The basic reaction force calculation unit, when any one of the plurality of types of axial force and the tire force acquired is abnormal, is compared to the case where any of the plurality of types of axial force and the tire force is not abnormal. 3. A steering control device for calculating the basic reaction force so as to increase the contribution ratio of forces other than the abnormal force to the basic reaction force.

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