JP2019209787A - Steering control device - Google Patents

Abstract

To provide a steering control device capable of achieving excellent steering feeling.SOLUTION: A reaction force component calculation part 63 comprises: a road surface axial force calculation part 81 for calculating a road surface axial force Fer; an ideal axial force calculation part 82 for calculating an ideal axial force Fib; and a distribution axial force calculation part 83 for distributing at a prescribed ratio, the ideal axial force fib and the road surface axial force Fer for calculating a distribution axial force Fd, so that the axial force applied from the road surface (road surface information transmitted from the road surface) to turning wheels is reflected. The reaction force component calculation part 63 comprises: a vehicle state amount axial force calculation part 91 for calculating a vehicle state amount axial force Fyr; a grip state amount calculation part 92 for calculating a grip state amount Gr indicating a grip state of the vehicle; and a distribution axial force adjustment part 88. The distribution axial force adjustment part 88 adjusts the distribution axial force Fd on the basis of the grip state amount Gr and the steering torque Th for calculating a reaction force component Fir.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a steering control device.

  Conventionally, an electric power steering device (EPS) using a motor as a drive source has been widely adopted as a steering device for a vehicle. In such a steering control device that uses EPS as a control target, there are various types to improve the steering feeling. Compensation control may be executed. For example, Patent Document 1 discloses a tire that detects a grip state of a tire (for example, a grip loss degree indicating a degree of tire grip loss) and varies the assist force according to the grip loss degree. The grip loss degree includes the assist torque calculated based on the steering torque, the inertia of the motor that applies the assist torque, the first self-aligning torque (SATa) calculated based on the frictional force, and the tire. It is obtained by calculating the difference between the second self-aligning torque (SATb) obtained from the product of the working lateral force and the trail.

  Now, in a steer-by-wire type steering apparatus that has been developed in recent years, power transmission between the steered wheels and the steering wheel is separated. For this reason, the road surface reaction force received by the steered wheels is not mechanically transmitted to the steering wheel. Therefore, in the steering control device that controls the steering device of the same type, the steering reaction in consideration of the road surface information is applied to the steering wheel. The force is applied by a steering side actuator (steering side motor). For example, in Patent Document 2, focusing on the axial force acting on the steered shaft connected to the steered wheels, the ideal axial force calculated from the target steered angle according to the target steered angle of the steering wheel, and the steered side There is disclosed a steering control device that determines a steering reaction force in consideration of a distributed axial force obtained by distributing a road surface axial force calculated from a driving current of a steered side motor that is a drive source of an actuator at a predetermined distribution ratio.

JP 2009-40341 A JP 2017-165219 A

  By the way, in a steering control device that controls a steer-by-wire type steering device, it is required to realize a better steering feeling, and even if the configuration as in Patent Document 2 is adopted, it is still required. The fact is that it cannot be said that this level has been reached. Therefore, the creation of a new technology that can realize a better steering feeling has been demanded.

  Note that the grip state detection method described in Patent Document 1 cannot be applied to a steer-by-wire type steering device because, for example, assist torque or the like is used as a parameter used to detect the grip loss degree.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a steering control device capable of realizing excellent steering feeling.

  A steering control device that solves the above problem is a structure in which a steering unit and a steering unit that steers steered wheels according to steering input to the steering unit are mechanically separated or mechanically connectable / disconnectable. And a control unit that controls the operation of a steering-side motor that applies a steering reaction force that is a force against steering that is input to the steering unit. The control unit includes the steered wheels. A plurality of types of axial force calculating units that calculate a plurality of types of axial forces acting on the steered shaft connected to each other on the basis of different state quantities, and the plurality of types of axial forces are added together with a distribution ratio set individually. A distributed axial force calculating unit that calculates a distributed axial force, a grip state amount calculating unit that calculates a grip state amount based on the plurality of types of axial forces, and adjusting the distributed axial force based on the grip state amount The distribution axial force adjustment unit and the distribution axial force adjustment unit A target steering angle calculation unit that calculates a target steering angle that is a target value of a steering angle of a steering wheel coupled to the steering unit in consideration of the adjusted distributed axial force that has been further adjusted; Based on the execution of angle feedback control for following the target steering angle, a target reaction force torque that is a target value of the steering reaction force is calculated.

  A steering control device that solves the above problem is a structure in which a steering unit and a steering unit that steers steered wheels according to steering input to the steering unit are mechanically separated or mechanically connectable / disconnectable. And a control unit that controls the operation of a steering-side motor that applies a steering reaction force that is a force against steering that is input to the steering unit. The control unit includes the steered wheels. A plurality of types of axial force calculating units that calculate a plurality of types of axial forces acting on the steered shaft connected to each other on the basis of different state quantities, and the plurality of types of axial forces are added together with a distribution ratio set individually. A distributed axial force calculating unit that calculates a distributed axial force, a grip state amount calculating unit that calculates a grip state amount based on the plurality of types of axial forces, and adjusting the distributed axial force based on the grip state amount Distributed axial force adjusting unit to be applied to the steering unit That computes a target reaction torque as a target value of the steering reaction force based on the steering torque and the adjusted allocation axial force adjusted by the allocation axial force adjustment unit.

  A steering control device that solves the above problem is a structure in which a steering unit and a steering unit that steers steered wheels according to steering input to the steering unit are mechanically separated or mechanically connectable / disconnectable. And a control unit that controls the operation of a steering-side motor that applies a steering reaction force that is a force against steering that is input to the steering unit. The control unit includes the steered wheels. A plurality of types of axial force calculating units that calculate a plurality of types of axial forces acting on the steered shaft connected to each other on the basis of different state quantities, and the plurality of types of axial forces are added together with a distribution ratio set individually. A distributed axial force calculating unit that calculates a distributed axial force, a grip state amount calculating unit that calculates a grip state amount based on the plurality of types of axial forces, and adjusting the distributed axial force based on the grip state amount The distribution axial force adjustment unit and the distribution axial force adjustment unit It computes a target reaction torque as a target value of the steering reaction force based on a more coordinated adjusted allocation axial force.

  Steering feeling is basically a sense of inertia, a sense of viscosity, a sense of rigidity expressed by an inertia term, a viscosity term, and a spring term in the equation of motion indicating the relationship between the input torque input to the steering device and the turning angle. Realized. By adjusting the distributed axial force corresponding to the spring term of the above-mentioned movement method based on the grip state amount as in each of the above configurations, the driver is given a sense of rigidity of steering operation according to the grip state as a response, Excellent steering feeling can be realized.

  In the steering control device, the distribution axial force adjustment unit includes a distribution adjustment gain calculation unit that calculates a distribution adjustment gain multiplied by the distribution axial force, and the distribution adjustment gain calculation unit is based on the grip state quantity. It is preferable to change the distribution adjustment gain.

  According to the above configuration, the distribution axial force is adjusted by multiplying the distribution adjustment gain. Since the distribution adjustment gain is changed based on the grip state quantity, it is possible to adjust the rigidity of the steering operation based on the gradient of the adjusted distribution axial force, that is, the change in the spring constant of the spring term.

In the steering control device, it is preferable that the distribution adjustment gain calculation unit changes the distribution adjustment gain according to a vehicle speed.
According to the above configuration, by adding the vehicle speed to the calculation of the distribution adjustment gain, a grip state that changes according to the vehicle speed can be given to the driver as a response through the rigidity of the steering operation realized based on the distribution adjustment gain. .

  In the steering control device, the distribution axial force adjustment unit includes an offset value calculation unit that calculates an offset value to be added to the distribution axial force, and the offset value calculation unit is configured to calculate the offset value based on the grip state quantity. Is preferably changed.

  According to the above configuration, the distribution axial force is adjusted by adding the offset value. And since the offset value is changed based on the grip state quantity, the rigidity feeling of the steering operation according to the grip state quantity can be given to the driver as a constant response regardless of the spring constant of the spring term. Steering feeling can be realized.

  In the steering control device, it is preferable that the distribution axial force adjustment unit adjusts the distribution axial force by adding the offset value when the steering unit is in a non-steering state where steering is not input to the steering unit.

  According to the above configuration, since the driver adjusts the distributed axial force by adding the offset value when the steering wheel is in the non-steering state, the steering speed of the steering wheel when returning can be adjusted according to the grip state.

In the steering control device, it is preferable that the offset value calculation unit changes the offset value according to a vehicle speed.
According to the above configuration, by adding the vehicle speed to the calculation of the offset value, a grip state that changes according to the vehicle speed can be given to the driver as a response through a sense of rigidity of the steering operation that is realized based on the offset value.

  According to the present invention, an excellent steering feeling can be realized.

The schematic block diagram of the steer-by-wire type steering apparatus of 1st Embodiment. The block diagram of the steering control apparatus of 1st Embodiment. The block diagram of the reaction force component calculating part of 1st Embodiment. The schematic diagram which shows the relationship between the lateral force which acts on an applied force point, the self aligning torque, and a pneumatic trail. The graph which shows the change of the ideal axial force with respect to the change of a slip angle, lateral force (both axial force of a vehicle state), self-aligning torque (road surface axial force), and a pneumatic trail. The block diagram of the distribution axial force adjustment part of 1st Embodiment. The block diagram of the steering side control part of 2nd Embodiment. The block diagram of the steering control apparatus of 3rd Embodiment. The block diagram of the steering control apparatus of 4th Embodiment. The schematic block diagram of the steer-by-wire type steering apparatus of a modification.

(First embodiment)
Hereinafter, a first embodiment of a steering control device will be described with reference to the drawings.
As shown in FIG. 1, a steer-by-wire type steering device 2 to be controlled by the steering control device 1 includes a steering unit 3 that is steered by a driver, and steered wheels 4 according to the steering of the steering unit 3 by the driver. And a steering section 5 that steers the wheel.

  The steering unit 3 includes a steering shaft 12 to which the steering wheel 11 is fixed, and a steering side actuator 13 that can apply a steering reaction force to the steering shaft 12. The steering-side actuator 13 includes a steering-side motor 14 serving as a drive source, and a steering-side speed reducer 15 that decelerates the rotation of the steering-side motor 14 and transmits it to the steering shaft 12.

  The steered portion 5 is capable of reciprocating between 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 the rack shaft 22. A rack housing 23 is provided. The first pinion shaft 21 and the rack shaft 22 are disposed with a predetermined crossing angle. The first pinion teeth 21 a formed on the first pinion shaft 21 and the first rack teeth 22 a formed on the rack shaft 22 The first rack and pinion mechanism 24 is configured by meshing. The rack shaft 22 is supported by the first rack and pinion mechanism 24 so that one end in the axial direction thereof can reciprocate. A tie rod 26 is connected to both ends of the rack shaft 22 via a rack end 25 formed of a ball joint, and a tip of the tie rod 26 is connected to a knuckle (not shown) to which the steered wheels 4 are assembled.

  Further, the steered portion 5 is provided with a steered side actuator 31 via a second pinion shaft 32 that imparts a steered force that steers the steered wheels 4 to the rack shaft 22. The steered side actuator 31 includes a steered side motor 33 serving as a drive source, and a steered side speed reducer 34 that decelerates the rotation of the steered side motor 33 and transmits it to the second pinion shaft 32. The second pinion shaft 32 and the rack shaft 22 are arranged with a predetermined crossing angle. The second pinion teeth 32 a formed on the second pinion shaft 32 and the second rack teeth 22 b formed on the rack shaft 22 The second rack and pinion mechanism 35 is configured. The rack shaft 22 is supported by the second rack and pinion mechanism 35 so that the other end in the axial direction can reciprocate.

  In the steering device 2 configured as described above, the second pinion shaft 32 is rotationally driven by the steered side actuator 31 in accordance with the steering operation by the driver, and this rotation is performed by the second rack and pinion mechanism 35 on the rack shaft 22. The turning angle of the steered wheels 4 is changed by being converted to axial movement. At this time, a steering reaction force against the driver's steering is applied to the steering wheel 11 from the steering side actuator 13.

Next, the electrical configuration of the present embodiment will be described.
The steering control device 1 is connected to the steering side actuator 13 (steering side motor 14) and the 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 every predetermined calculation cycle.

  A vehicle speed sensor 41 that detects the vehicle speed V of the vehicle and a torque sensor 42 that detects the steering torque Th applied to the steering shaft 12 are connected to the steering control device 1. The torque sensor 42 is provided closer to the steering wheel 11 than the portion of the steering shaft 12 connected to the steering actuator 13 (steering reduction gear 15). Further, the steering control device 1 includes a steering-side rotation sensor 43 that detects the rotation angle θs of the steering-side motor 14 as a detection value indicating the steering amount of the steering unit 3 with a relative angle within a range of 360 °, and a steering unit. A turning-side rotation sensor 44 that detects a rotation angle θt of the turning-side motor 33 as a detected value indicating a turning amount of 5 is connected. In addition, a yaw rate sensor 45 that detects the yaw rate γ of the vehicle and a lateral acceleration sensor 46 that detects the lateral acceleration LA of the vehicle are connected to the steering control device 1. The steering torque Th and the rotation angles θs and θt are positive values when steering in one direction (right in the present embodiment) and negative values when steering in the other direction (left in the present embodiment). Detect as. The steering control device 1 controls the operations of the steering side motor 14 and the steered side motor 33 based on these various state quantities.

Hereinafter, the configuration of the steering control device 1 will be described in detail.
As shown in FIG. 2, the steering control device 1 supplies driving power to the steering side motor 14 based on the steering side control unit 51 as a control unit that outputs the steering side motor control signal Ms and the steering side motor control signal Ms. And a steering side drive circuit 52 to be supplied. The steering control unit 51 detects the phase current values Ius, Ivs, and Iws of the steering side motor 14 that flow through the connection line 53 between the steering side drive circuit 52 and the motor coil of each phase of the steering side motor 14. A current sensor 54 is connected. In FIG. 2, for convenience of explanation, each phase connection line 53 and each phase current sensor 54 are collectively shown as one.

  Further, the steering control device 1 includes a steered side control unit 55 that outputs a steered side motor control signal Mt, and a steered side that supplies driving power to the steered side motor 33 based on the steered side motor control signal Mt. And a drive circuit 56. The steered side control unit 55 includes respective phase current values Iut, Ivt, and the like of the steered side motor 33 flowing through the connection lines 57 between the steered side drive circuit 56 and the motor coils of the respective phases of the steered side motor 33. A current sensor 58 for detecting Iwt is connected. In FIG. 2, for convenience of explanation, each phase connection line 57 and each phase current sensor 58 are shown together as one. In the steering side drive circuit 52 and the steered side drive circuit 56 of the present embodiment, known PWM inverters having a plurality of switching elements (for example, FETs) are respectively employed. The steering side motor control signal Ms and the steered side motor control signal Mt are gate on / off signals that define the on / off states of the respective switching elements.

  The steering control device 1 executes each calculation process shown in the following control blocks every predetermined calculation cycle, and generates a steering side motor control signal Ms and a steered side motor control signal Mt. The steering side motor control signal Ms and the steered side motor control signal Mt are output to the steered side drive circuit 52 and the steered side drive circuit 56, whereby each switching element is turned on and off, and the steered side motor 14 and the steered side are turned on. Driving power is supplied to the side motor 33. Thereby, the operation of the steering side actuator 13 and the steering side actuator 31 is controlled.

First, the configuration of the steering side control unit 51 will be described.
The steering side controller 51 receives the vehicle speed V, steering torque Th, rotation angle θs, lateral acceleration LA, yaw rate γ, phase current values Ius, Ivs, Iws, and q-axis current value Iqt. And the steering side control part 51 produces | generates and outputs the steering side motor control signal Ms based on these each state quantity.

  Specifically, the steering side control unit 51 includes a steering angle calculation unit 61 that calculates the steering angle θh of the steering wheel 11 based on the rotation angle θs of the steering side motor 14. Further, the steering side control unit 51 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, and a reaction force component that is a force that resists rotation of the steering wheel 11. And a reaction force component calculation unit 63 for calculating Fir. The steering-side control unit 51 includes a target steering angle calculation unit 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 force torque calculation unit 65 that calculates a target reaction force torque Ts * based on the steering angle θh and the target steering angle θh *, and a steering side based on the target reaction force torque Ts *. A steering side motor control signal generation unit 66 for generating a motor control signal Ms.

  The steering angle calculation unit 61 obtains the input rotation angle θs by converting it into an absolute angle in a range 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 calculation unit 61 calculates the steering angle θh by multiplying the rotation angle converted into the absolute angle by the conversion coefficient Ks based on the rotation speed ratio of the steering-side speed reducer 15.

  The steering torque Th is input to the input torque basic component calculation unit 62. The input torque basic component calculation unit 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 is larger. The input torque basic component Tb * is input to the target steering angle calculation unit 64 and the target reaction force torque calculation unit 65.

  In addition to the steering torque Th, the vehicle speed V, and the input torque basic component Tb *, a reaction force component Fir calculated by a reaction force component calculation unit 63 described later is input to the target steering angle calculation unit 64. The target steering angle calculation unit 64 is a model (steering model) that relates the input torque Tin *, which is a value obtained by adding the steering torque Th to the input torque basic component Tb * and subtracting the reaction force component Fir, and the target steering angle θh *. ) To calculate the target steering angle θh *. In this model formula, the steering wheel 11 (steering unit 3) and the steered wheels 4 (steering unit 5) are mechanically coupled, and the torque and rotation of the rotating shaft that rotates as the steering wheel 11 rotates. It is a representation of the relationship with the corner. This model equation is expressed using a viscosity coefficient C that models the friction of the steering device 2 and an inertia coefficient J that models the inertia of the steering device 2. The viscosity coefficient C and the inertia coefficient J are variably set according to the vehicle speed V. The target steering angle θh * calculated using the model formula in this way is output to the reaction force component calculation unit 63 in addition to the subtractor 69 and the steered side control unit 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 the subtractor 69. Then, the target reaction torque calculation unit 65 is based on the basis of the steering reaction force applied by the steering side motor 14 as a control amount for feedback control of the steering angle θh to the target steering angle θh * based on the angle deviation Δθs. The reaction force torque is calculated, and the target reaction force torque Ts * is calculated by adding the input torque basic component Tb * to the basic reaction force torque. Specifically, the target reaction force torque calculator 65 calculates the sum of the output values of the proportional element, the integral element, and the derivative element that receive the angle deviation Δθs as the basic reaction force torque.

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

  The steering side motor control signal generator 66 generates (calculates) a steering side motor control signal Ms to be output to the steering side drive circuit 52 by executing current feedback control in the d / q coordinate system. Specifically, the steering side motor control signal generation unit 66 maps the phase current values Ius, Ivs, Iws on the d / q coordinates based on the rotation angle θs. The d-axis current value Ids and the q-axis current value Iqs, which are actual current values of the steering side motor 14 in the d / q coordinate system, are calculated. Then, the steering-side motor control signal generation unit 66 sets d-axis current value Ids to follow d-axis target current value Ids * and d-axis current value Iqs to follow q-axis target current value Iqs *. A voltage command value is calculated based on each current deviation on the shaft and the q axis, and a steering side motor control signal Ms having a duty ratio based on the voltage command value is generated. When the steering side motor control signal Ms calculated in this way is output to the steering side drive circuit 52, drive power corresponding to the steering side motor control signal Ms is output to the steering side motor 14, and its operation is controlled. Is done.

Next, the steered side control unit 55 will be described.
The turning side control unit 55 receives the rotation angle θt, the target steering angle θh *, and the phase current values Iut, Ivt, Iwt of the turning side motor 33. And the steered side control part 55 produces | generates and outputs the steered side motor control signal Mt based on each of these state quantities.

  Specifically, the turning side control unit 55 calculates a turning corresponding angle θp corresponding to the turning angle (pinion angle) of the first pinion shaft 21 that is a rotating shaft that can be converted into the turning angle of the steered wheels 4. A rudder corresponding angle calculation unit 71 is provided. The steered side control unit 55 calculates a target turning torque Tt * based on the steering corresponding angle θp and the target steering angle θh *, and based on the target turning torque Tt *. And a steered side motor control signal generating unit 73 for generating a steered side motor control signal Mt. In the steering device 2 of the present embodiment, the steering angle ratio that is the ratio of the steering angle θh and the steering response angle θp is set to be constant, and the target steering response angle is equal to the target steering angle θh *. .

  The turning correspondence angle calculation unit 71 converts the input rotation angle θt into an absolute angle in a range exceeding 360 ° by counting the number of rotations of the turning side motor 33 from a neutral position where the vehicle goes straight, for example. And get. Then, the turning correspondence angle calculation unit 71 converts the rotation angle converted into the absolute angle 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. The steering response angle θp is calculated by multiplying the coefficient Kt. That is, the steering corresponding angle θp corresponds to the steering angle θh of the steering wheel 11 when the first pinion shaft 21 is assumed to be connected to the steering shaft 12.

  An angle deviation Δθp obtained by subtracting the steering response angle θp from the target steering angle θh * (target steering response angle) in the subtractor 74 is input to the target steering torque calculation unit 72. Then, the target turning torque calculator 72 calculates the turning force applied by the turning side motor 33 as a control amount for feedback control of the turning corresponding angle θp to the target steering angle θh * based on the angle deviation Δθp. A target turning torque Tt * that 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 derivative element that receive the angle deviation Δθp as the target turning torque Tt *.

  In addition to the target turning torque Tt *, the turning side motor control signal generation unit 73 receives the rotation angle θt and the phase current values Iut, Ivt, Iwt. Then, the steered side motor control signal generating unit 73 calculates the q-axis target current value Iqt * on the q-axis in the d / q coordinate system based on the target steered torque Tt *. In the present embodiment, the d-axis target current value Idt * on the d-axis is set to zero.

  The steered side motor control signal generation unit 73 generates (calculates) a steered side motor control signal Mt to be output to the steered side drive circuit 56 by executing current feedback control in the d / q coordinate system. Specifically, the steered side motor control signal generation unit 73 maps the phase current values Iut, Ivt, and Iwt on the d / q coordinate based on the rotation angle θt, thereby turning in the d / q coordinate system. The d-axis current value Idt and the q-axis current value Iqt, which are actual current values of the side motor 33, are calculated. Then, the steered side motor control signal generator 73 makes the d-axis current value Idt follow the d-axis target current value Idt *, and the q-axis current value Iqt follows the q-axis target current value Iqt *. A voltage command value is calculated based on the current deviation on the d-axis and the q-axis, and a steered side motor control signal Mt having a duty ratio based on the voltage command value is generated. When the steered side motor control signal Mt calculated in this way is output to the steered side drive circuit 56, drive power corresponding to the steered side motor control signal Mt is output to the steered side motor 33, Its operation is controlled. The q-axis current value Iqt calculated in the process of generating the steered side motor control signal Mt is output to the reaction force component calculation unit 63.

Next, the configuration of the reaction force component calculation unit 63 will be described.
The reaction force component calculation unit 63 receives the vehicle speed V, the steering torque Th, the lateral acceleration LA, the yaw rate γ, the q-axis current value Iqt of the steered side motor 33, and the target steering angle θh *. The reaction force component calculation unit 63 calculates a reaction force component Fir (base reaction force) corresponding to the axial force acting on the rack shaft 22 based on these state quantities, and outputs it to the target steering angle calculation unit 64.

  As shown in FIG. 3, the reaction force component calculation unit 63 includes a road surface axial force calculation unit 81 as an axial force calculation unit that calculates a road surface axial force Fer and an ideal as an axial force calculation unit that calculates an ideal axial force Fib. And an axial force calculation unit 82. The road surface axial force Fer and the ideal axial force Fib are calculated by a torque dimension (N · m). In addition, the reaction force component calculation unit 63 applies the ideal axial force Fib and the road surface axial force Fer to a predetermined ratio 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. And a distribution axial force calculation unit 83 that calculates the distribution axial force Fd by distributing the distribution axial force Fd.

  A target steering angle θh * (target steering response angle) and a vehicle speed V are input to the ideal axial force calculation unit 82. The ideal axial force calculator 82 is an ideal value of the axial force acting on the steered wheels 4 (transmitted force transmitted to the steered wheels 4), and the ideal axial force Fib that does not reflect road surface information is used as the target steering angle θh *. Calculate based on. Specifically, the ideal axial force calculation unit 82 calculates the absolute value of the ideal axial force Fib as the absolute value of the target steering angle θh * increases. Further, the ideal axial force calculation unit 82 calculates the absolute value of the ideal axial force Fi as the vehicle speed V increases. The ideal axial force Fib thus calculated is output to the multiplier 84.

  The q-axis current value Iqt of the steered side motor 33 is input to the road surface axial force calculation unit 81. The road surface axial force calculation unit 81 is an estimated value of the axial force acting on the steered wheels 4 (transmitted force transmitted to the steered wheels 4), and the road surface axial force Fer reflecting the road surface information is converted to a q-axis current value Iqt. Calculate based on Specifically, the road surface axial force calculation unit 81 determines that the torque applied to the rack shaft 22 by the steered side motor 33 and the torque corresponding to the force applied from the road surface to the steered wheels 4 are balanced. Calculation is performed so that the absolute value of the road surface axial force Fer increases as the absolute value of the current value Iqt increases. The road surface axial force Fer calculated in this way is output to the multiplier 85.

  In addition to the vehicle speed V, the road surface axial force Fer and the ideal axial force Fib are input to the distribution axial force calculation unit 83. The distribution axial force calculation unit 83 includes a distribution gain calculation unit 86 for calculating a distribution gain Gib and a distribution gain Ger that are distribution ratios for distributing the ideal axial force Fib and the road surface axial force Fer based on the vehicle speed V. I have. The distribution gain calculation unit 86 of this embodiment includes a map that defines the relationship between the vehicle speed V and the distribution gain Gib and Ger, and calculates the distribution gain Gib and Ger according to the vehicle speed V by referring to the map. To do. The distribution gain Gib is smaller when the vehicle speed V is large than when it is small, and the distribution gain Ger is larger when the vehicle speed V is large than when it is small. In the present embodiment, the value is set so that the sum of the distribution gains Gib and Ger is “1”. The distribution gain Gib calculated in this way is output to the multiplier 84, and the distribution gain Ger is output to the multiplier 85.

  The distribution axial force calculation unit 83 multiplies the ideal axial force Fib by the distribution gain Gib in the multiplier 84, multiplies the road surface axial force Fer by the distribution gain Ger in the multiplier 85, and adds these values in the adder 87. In addition, the distribution axial force Fd is calculated. The distribution axial force Fd calculated in this way is output to a distribution axial force adjustment unit 88 described later.

  The reaction force component calculation unit 63 includes a vehicle state quantity axial force calculation unit 91 as an axial force calculation unit that calculates the vehicle state quantity axial force Fyr, and a grip state that calculates a grip state quantity Gr that indicates the grip state of the vehicle. A quantity calculation unit 92. The vehicle state quantity axial force Fyr is calculated by the torque dimension (N · m). The vehicle state quantity axial force calculation unit 91 receives the yaw rate γ and the lateral acceleration LA as vehicle state quantities. The vehicle state quantity axial force calculation unit 91 calculates the lateral force Fy by inputting the yaw rate γ and the lateral acceleration LA into the following equation (1).

Lateral force Fy = Kla × lateral acceleration LA + Kγ × γ ′ (1)
“Γ ′” indicates a differential value of the yaw rate γ, and “Kla” and “Kγ” indicate coefficients set in advance by a test or the like. Then, the vehicle state quantity axial force calculation unit 91 can consider that the lateral force Fy calculated in this way can be regarded as an axial force acting on the rack shaft 22 approximately. Output as force Fyr.

  The grip state amount calculation unit 92 receives the vehicle state amount axial force Fyr and the road surface axial force Fer. The grip state quantity calculation unit 92 inputs the vehicle state quantity axial force Fyr and the road surface axial force Fer to the following equation (2), and thereby the grip state quantity including the grip degree indicating how much the steered wheels 4 are gripped. Gr is calculated.

Grip state amount Gr = (Ker × road surface axial force) / (Ky × vehicle state amount axial force) (2)
“Ker” and “Ky” indicate coefficients set in advance by a test or the like.
Here, the relationship between the slip angle β of the steered wheels and the force acting on the steered wheels will be described with reference to FIGS. 4 and 5.

  FIG. 4 is a view of the ground contact surface of the steered wheel with the slip angle β as viewed from above. A center line x toward the direction of the steered wheel indicates the original direction of the steered wheel, and the traveling direction of the steered wheel is indicated by a line α. In the figure, if point A is the contact start point of the steered wheel and point B is the contact end point, the tread surface is dragged by the slip angle β along the line α from the center line x. Bend. In FIG. 4, a region where the tread surface is displaced and bent is indicated by hatching. Among the bent areas, the area on the A point side is an adhesive area, and the area on the B point side is a sliding area. Then, the lateral force Fy acts on the force applied to the ground contact surface of the steered wheel when turning at such a slip angle β, and the moment around the vertical axis becomes the self-aligning torque SAT. The distance between the ground contact center of the steered wheels and the force point is the pneumatic trail, and the sum of the pneumatic trail and the caster trail is the trail.

  FIG. 5 shows changes in ideal axial force Fi, lateral force Fy (vehicle state amount axial force Fyr), self-aligning torque SAT (road surface axial force Fer), and pneumatic trail with respect to a change in slip angle β. . As shown in the figure, the ideal axial force Fib, lateral force Fy, and self-aligning torque SAT increase approximately linearly as the slip angle β increases in the turning angle of the steered wheels that are turning. However, the difference between these values is small. On the other hand, in the region where the slip angle β is large to some extent, the ideal axial force Fi continues to increase substantially linearly as the slip angle β increases, but the lateral force Fy shows a substantially constant or slightly decreasing tendency after continuing to increase. Further, the self-aligning torque SAT continues to increase for a while as the slip angle β increases, but shows a tendency to greatly decrease as the pneumatic trail decreases. Thus, each value changes approximately linearly, a region where these differences are small is defined as a normal region, and a region where the lateral force Fy and the self-aligning torque SAT change nonlinearly and these differences are large is defined as a limit region. . Note that the separation between the normal area and the limit area shown in FIG. 5 is for convenience.

  Here, if the axial force at the time of turning is regarded as the self-aligning torque SAT, the relationship between the self-aligning torque SAT and the lateral force Fy is as shown in FIG. 4 from the ground contact center between the steered wheel and the road surface. It can be expressed by the following equation (3) using parameters corresponding to the pneumatic trail up to the force point.

Self-aligning torque SAT = lateral force Fy × pneumatic trail (3)
When the self-aligning torque SAT is considered as “axial force≈reaction force from the road surface”, the road surface axial force Fer based on the driving current of the steered side motor 33 (that is, the q-axis current value Iqt) is calculated as the self-aligning torque. It can be said that SAT is expressed approximately.

  Further, the lateral force Fy is a force generated in the steered wheels 4 and is replaced with “lateral force Fy≈force generated in the lateral direction of the vehicle”, and the lateral force Fy is approximately expressed by the lateral acceleration LA. be able to. Note that, with only the lateral acceleration LA, the response at the start of movement is insufficient with respect to the actual axial force. Therefore, in order to improve the response, the derivative of the yaw rate γ is added to obtain the above equation (1).

Further, the grip state amount Gr can be expressed by the following equation (4) by the above equation (3).
Grip state quantity Gr = self-aligning torque SAT / lateral force Fy (4)
Then, considering that the road surface axial force Fer can approximately represent the self-aligning torque SAT and the vehicle state amount axial force Fyr can approximately represent the lateral force, the grip state amount Gr is expressed by the above equation (2). expressed.

  As shown in FIG. 3, the grip state amount Gr calculated by the grip state amount calculating unit 92 is output to the distribution axial force adjusting unit 88. Then, the distribution axial force adjustment unit 88 adjusts the distribution axial force Fd input from the distribution axial force calculation unit 83 based on the grip state amount Gr, the steering torque Th, and the vehicle speed V, so that the distribution axial force Fd is adjusted. The reaction force component Fir is calculated and output to the target steering angle calculation unit 64.

Next, the configuration of the distribution axial force adjustment unit 88 will be described.
As shown in FIG. 6, the distribution axial force adjustment unit 88 includes a distribution adjustment gain calculation unit 101. The distribution adjustment gain calculation unit 101 receives the grip state amount Gr and the vehicle speed V. The distribution adjustment gain calculation unit 101 includes a map that defines the relationship between the grip state amount Gr and the vehicle speed V and the distribution adjustment gain Kaa. By referring to the map, distribution according to the grip state amount Gr and the vehicle speed V is provided. The adjustment gain Kaa is calculated. In this map, the distribution adjustment gain Kaa is “1” in the region where the grip state amount Gr is equal to or less than the grip threshold Grth, and when the grip state amount Gr is greater than the grip threshold Grth, the distribution is based on the increase in the grip state amount Gr. The adjustment gain Kaa is set to be large. The grip threshold Grth is a value indicating the grip state amount Gr at the slip angle β that is the boundary between the normal region and the limit region, and is set in advance by a test or the like. Further, the map is set so that the distribution adjustment gain Kaa is increased based on the increase in the vehicle speed V in the region where the grip state amount Gr is larger than the grip threshold Grth. Note that the shape of the map can be changed as appropriate, and even in a region where the grip state amount Gr is larger than the grip threshold Grth, the distribution adjustment gain Kaa is set to be small based on the increase of the grip state amount Gr. Alternatively, the distribution adjustment gain Kaa may be set to be small based on the increase in the vehicle speed V.

  The distribution adjustment gain Kaa calculated in this way is input to the multiplier 102 together with the distribution axial force Fd. The distribution axial force adjustment unit 88 outputs a value obtained by multiplying the distribution axial force Fd by the distribution adjustment gain Kaa in the multiplier 102 to the adder 103 as a gradient adjustment distribution axial force Fd ′. In addition, the distribution axial force adjustment unit 88 includes an offset value calculation unit 104 and a non-steering gain calculation unit 105.

  The offset value calculation unit 104 receives the grip state amount Gr and the vehicle speed V. The offset value calculation unit 104 includes a map that defines the relationship between the grip state amount Gr and the vehicle speed V and the offset value Of, and the offset value Of corresponding to the grip state amount Gr and the vehicle speed V by referring to the map. Is calculated. In this map, the offset value is “0” in the region where the grip state amount Gr is equal to or less than the grip threshold Grth, and when the grip state amount Gr is larger than the grip threshold Grth, the offset value Of is based on the increase in the grip state amount Gr. Is set to be large. Further, the map is set so that the offset value Of is increased based on the increase in the vehicle speed V in a region where the grip state amount Gr is larger than the grip threshold Grth. The shape of the map can be changed as appropriate. For example, in a region where the grip state amount Gr is larger than the grip threshold value Grth, the offset value Of becomes smaller (becomes a negative value) based on the increase in the grip state amount Gr. Or may be set so that the offset value Of becomes smaller based on the increase in the vehicle speed V. The offset value Of calculated in this way is output to the multiplier 106.

  The non-steering gain calculator 105 receives the steering torque Th. The non-steering gain calculation unit 105 includes a map that defines the relationship between the steering torque Th and the non-steering gain Kns, and calculates the non-steering gain Kns according to the steering torque Th by referring to the map. This map shows that when the absolute value of the steering torque Th is “0”, the non-steering gain Kns becomes “1”, and the non-steering gain Kns decreases as the absolute value of the steering torque Th increases, and the steering torque Th When the absolute value becomes larger than the non-steering threshold value Tth, the non-steering gain Kns is set to be “0”. The non-steering threshold value Tth is a value that is recognized as a steering operation being performed by the driver, and is set in advance to a value near zero. The non-steering gain Kns calculated in this way is output to the multiplier 106.

  The distribution axial force adjustment unit 88 outputs to the adder 103 an offset value Of ′ obtained by multiplying the offset value Of by the non-steering gain Kns in the multiplier 106. Then, the distribution axial force adjustment unit 88 calculates, in the adder 103, a value obtained by adding the offset value Of 'to the gradient adjustment distribution axial force Fd' as a reaction force component Fir. As described above, the non-steering gain Kns becomes “0” when the steering operation is performed by the driver, so that the offset value Of is added and the distributed axial force Fd is adjusted only during non-steering. It becomes.

Next, a change in the steering feeling accompanying the adjustment of the distribution axial force Fd will be described.
For example, assuming that the vehicle travels on a low μ road surface and the slip angle β is likely to increase, the reaction force component Fir is adjusted to be smaller based on the grip state amount Gr than the distributed axial force Fd. To do. In this case, for example, from the stage before the slip angle β increases and enters the limit region, the steering reaction force applied to the steering wheel 11 from the steering side motor 14 can be made smaller than usual, and a so-called feeling of slipping occurs. The driver can easily recognize road surface information such as a low μ road.

  On the other hand, a case is assumed in which the reaction force component Fir is adjusted to be larger based on the grip state amount Gr than the distribution axial force Fd. In this case, for example, even when the slip angle β is increased, the steering reaction force applied from the steering motor 14 to the steering wheel 11 can be increased, and the driver can continue steering without a sense of incongruity.

The operation and effect of this embodiment will be described.
(1) The steering-side control unit 51 adjusts the distribution axial force Fd based on the grip state amount Gr, and changes the steering reaction force in consideration of the reaction force component Fir as the adjusted post-adjustment distribution axial force. . Here, the steering feeling is basically a sense of inertia represented by an inertia term, a viscosity term, and a spring term in the equation of motion indicating the relationship between the input torque Tin * input to the steering device 2 and the turning angle. Realized with a sense of viscosity and rigidity. By adjusting the distribution axial force Fd corresponding to the spring term of the above-mentioned movement process based on the grip state amount Gr as in the present embodiment, the rigidity of the steering operation according to the grip state is given to the driver as a response. In addition, excellent steering feeling can be realized.

  (2) The distribution axial force adjustment unit 88 includes a distribution adjustment gain calculation unit 101 that calculates a distribution adjustment gain Kaa that is multiplied by the distribution axial force Fd, and adjusts the distribution axial force Fd by multiplying the distribution adjustment gain Kaa. . Then, the distribution adjustment gain calculation unit 101 changes the distribution adjustment gain Kaa based on the grip state amount Gr, and therefore, based on the gradient of the reaction force component Fir (adjusted distribution axial force), that is, based on the change in the spring constant of the spring term. The rigidity of steering operation can be adjusted.

  (3) Since the distribution adjustment gain calculation unit 101 changes the distribution adjustment gain Kaa according to the vehicle speed V, a grip feeling that changes according to the vehicle speed V is realized based on the distribution adjustment gain Kaa. Can be given to the driver as a response.

  (4) The distribution axial force adjustment unit 88 includes an offset value calculation unit 104 that calculates an offset value Of added to the distribution axial force Fd, and adjusts the distribution axial force Fd by adding the offset value Of. Since the offset value calculation unit 104 changes the offset value Of based on the grip state amount Gr, the steering operation rigidity according to the grip state amount Gr has a certain response regardless of the spring constant of the spring term. Since it can be given to the driver, an excellent steering feeling can be realized.

  (5) The distribution axial force adjusting unit 88 includes a non-steering gain calculating unit 105 that calculates a non-steering gain Kns that is multiplied by the offset value Of, and the non-steering gain calculating unit 105 has an offset value Of of zero only during non-steering. The calculation is performed so that the value becomes larger than that. Therefore, in a state where the driver is not substantially steering the steering wheel 11, the offset value Of is added to adjust the distribution axial force Fd, so that the steering speed ωh of the steering wheel 11 at the time of return depends on the grip state. Can be adjusted.

  (6) Since the offset value calculation unit 104 changes the offset value Of according to the vehicle speed V, the grip state that changes according to the vehicle speed V is responded through the rigidity of the steering operation that is realized based on the offset value Of. It can be given to the driver.

(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 in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 7, the input torque basic component calculation unit 62 of the present embodiment calculates a torque command value Th * that is a target value of the steering torque Th that the driver should input with respect to the drive torque Tc. A value calculation unit 111 and a torque feedback control unit (hereinafter referred to as a torque F / B control unit) 112 that performs torque feedback calculation are provided.

  Specifically, the torque command value calculation unit 111 receives the drive torque Tc obtained by adding the input torque basic component Tb * to the steering torque Th in the adder 113. 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 is larger.

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

  The input torque basic component Tb * calculated in this way is output to the target reaction torque calculation unit 65 and output to the adder 113 as in the first embodiment. As a result, similarly to the first embodiment, the target steering angle calculator 64 calculates the target steering angle θh *, and the target reaction force torque calculator 65 calculates the target reaction force torque Ts *.

  The reaction force component calculation unit 63 calculates a reaction force component Fir (adjusted distributed axial force) adjusted based on the grip state amount Gr, as in the first embodiment. As a result, the target steering angle θh * is changed, and the target reaction force torque Ts * is changed.

As described above, the present embodiment has the same operations and effects as the operations (1) to (6) 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 in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 8, the steering-side control unit 51 of the present embodiment calculates a target turning correspondence angle θp * that is a target value of the turning correspondence angle θp that can be converted into the turning angle of the steered wheels 4. The steering corresponding angle calculation unit 121 is provided, and the target steering angle calculation unit 64 is not provided.

  The steering side control unit 51 includes an adder 122 to which an input torque basic component Tb * is input together with the steering torque Th, and the adder 122 adds these to calculate the drive torque Tc. Further, the steering side control unit 51 includes a subtractor 123 to which the reaction force component Fir is input together with the drive torque Tc, and the input torque Tin * is obtained by subtracting the reaction force component Fir from the drive torque Tc in the subtractor 123. Calculate. The input torque Tin * calculated in this way is output to the target reaction torque calculation unit 65 and the target turning corresponding angle calculation unit 121. The target reaction force torque calculation unit 65 calculates a target reaction force torque Ts * that 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 force torque calculator 65 calculates the target reaction force torque Ts * having a larger absolute value as the input torque Tin * is larger.

  An input torque Tin * and a vehicle speed V are input to the target turning corresponding angle calculation unit 121. The target turning correspondence angle calculation unit 121 calculates the target turning correspondence angle θp * by the same calculation process as the calculation process when the target steering angle calculation unit 64 of the first embodiment calculates the target steering angle θh *. To do. The target turning response 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 turning side control unit 55 and the reaction force component calculation unit 63. .

  The reaction force component calculation unit 63 calculates a reaction force component Fir (adjusted distributed axial force) adjusted based on the grip state amount Gr, as in the first embodiment. The input torque Tin * is changed based on the reaction force component Fir based on the grip state amount Gr. As a result, the target reaction torque Ts * based on the input torque Tin * is changed according to the grip state.

As described above, the present embodiment has the same operations and effects as the operations (1) to (6) 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 in the third embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 9, 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 force torque calculation unit 65 calculates the target reaction force torque Ts * having a larger absolute value as the absolute value of the reaction force component Fir is larger and as the vehicle speed V is larger.

  The reaction force component calculation unit 63 calculates a reaction force component Fir (adjusted distributed axial force) adjusted based on the grip state amount Gr, as in the first embodiment. As a result, the target reaction force torque Ts * is changed.

As described above, the present embodiment has the same operations and effects as the operations (1) to (6) of the first embodiment.
The present embodiment can be implemented with the following modifications. This embodiment and the following modifications can be implemented in combination with each other within a technically consistent range.

  In the third and fourth embodiments, the target turning response angle θp * is calculated based on the input torque Tin *, but is not limited thereto, and is calculated based on other parameters such as the steering angle θh. Also good.

In each of the above embodiments, the distribution axial force adjustment unit 88 may not have the non-steering gain Kns.
In each of the above embodiments, the non-steering gain calculator 105 calculates the non-steering gain Kns based on the steering torque Th (torsion bar torque) detected by the torque sensor 42. However, the present invention is not limited to this, and the non-steering gain Kns may be calculated based on the torque (estimated steering torque) applied to the steering wheel 11 by the driver. The estimated steering torque can be detected by, for example, a sensor provided on the steering wheel 11 or can be obtained by calculation from the steering torque Th.

  In each of the above embodiments, the distribution axial force adjustment unit 88 adjusts the distribution axial force Fd by simply multiplying the distribution adjustment gain Kaa or adding the offset value Of, and can be changed as appropriate. is there.

In each of the above embodiments, the distribution adjustment gain Kaa may be constant without being changed according to the vehicle speed V. Similarly, the offset value Of may not be changed according to the vehicle speed V but may be constant.
In each of the above embodiments, the grip degree obtained by dividing the road surface axial force Fer by the vehicle state quantity axial force Fyr is defined as the grip state quantity Gr. However, the present invention is not limited thereto, and for example, the vehicle state quantity axial force Fyr is calculated from the road surface axial force Fer. The grip loss degree (a value indicating how much the grip of the steered wheels 4 is lost) may be used as the grip state amount Gr.

  In the above embodiments, the grip state amount Gr is calculated based on the road surface axial force Fer and the vehicle state amount axial force Fyr. However, the present invention is not limited to this, and the grip state amount Gr can be calculated based on a plurality of types of axial forces. For example, based on the road surface axial force Fer and the ideal axial force Fib, or the road surface axial force Fer and the ideal axial force. The grip state amount Gr may be calculated based on Fi and the vehicle state amount axial force Fyr. Further, an axial force other than the ideal axial force Fib, the road surface axial force Fer, and the vehicle state quantity axial force Fyr may be calculated, and the axial force may be used for calculating the grip state quantity Gr.

  In each of the above embodiments, the road surface axial force Fer is calculated based on the q-axis current value Iqt. However, the present invention is not limited to this. For example, the rack shaft 22 is provided with a pressure sensor or the like that can detect the axial force, You may use as axial force Fer.

  In each of the above embodiments, the ideal axial force Fib is calculated based on the target steering angle θh * (target steering response angle) and the vehicle speed V. However, the present invention is not limited to this, and the target steering angle θh * (target steering response angle) ) Only on the basis of the steering response angle θp. Further, for example, the calculation may be performed by other methods such as adding other parameters such as the steering torque Th and the vehicle speed V.

  In each of the above embodiments, the ideal axial force Fib and the road surface axial force Fer are distributed at a predetermined ratio to calculate the distributed axial force Fd. However, the present invention is not limited to this. For example, the ideal axial force Fib and the vehicle state both axial force Fyr May be calculated at a predetermined ratio to calculate the distribution axial force Fd, and the calculation mode of the distribution axial force Fd can be changed as appropriate.

  In the above embodiment, the vehicle state biaxial force Fyr is calculated based on the yaw rate γ and the lateral acceleration LA. However, the present invention is not limited to this. For example, the vehicle state biaxial force is based on only one of the yaw rate γ and the lateral acceleration LA. The force Fyr may be calculated.

  In each of the above embodiments, the distribution axial force calculation unit 83 may calculate the distribution gains Gib and Ger in consideration of parameters other than the vehicle speed V. For example, in a vehicle in which a drive mode indicating a setting state of a control pattern such as an in-vehicle engine can be selected from a plurality of drive modes, the drive mode may be used as a parameter for setting the distribution gains Gib and Ger. In this case, it is possible to employ a configuration in which the distribution axial force calculation unit 83 includes a plurality of maps having different tendencies with respect to the vehicle speed V for each drive mode, and the distribution gains Gib and Ger are calculated by referring to the maps.

  In each of the above embodiments, the reaction force component calculation unit 63 calculates the adjusted distributed axial force as the reaction force component Fir, but is not limited to this, for example, a value obtained by adding another reaction force to the adjusted distributed axial force May be calculated 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, it is possible to employ an end reaction force that is a reaction force that resists further turning steering. As the rudder angle threshold, for example, the virtual rack end set to the neutral position side with respect to the mechanical rack end position in which the axial movement of the rack shaft 22 is regulated by the rack end 25 coming into contact with the rack housing 23. It is possible to use the steering corresponding angle θp at a position near the virtual rack end that is located on the neutral position side by a predetermined angle with respect to the position. Further, the steering angle θh at the rotation end position of the steering wheel 11 can also be used as the steering angle threshold value.

  In each of the above embodiments, the target steering angle calculation unit 64 sets the target steering angle θh * based on the steering torque Th and the vehicle speed V. However, the present invention is not limited to this, and if it is set based on at least the steering torque Th, For example, the vehicle speed V may not be used.

  In each of the above embodiments, the steering angle ratio between the steering angle θh and the steering response angle θp is constant. However, the present invention is not limited to this, and these may be variable according to the vehicle speed or the like. In this case, the target steering angle θh * and the target turning response angle are different values.

  In each of the above-described embodiments, the target steering angle calculation unit 64 uses the spring coefficient K determined by the specifications such as the suspension and the wheel alignment, and uses the model formula that is modeled by adding a so-called spring term. The angle θh * may be calculated.

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

In each of the above embodiments, the rack shaft 22 may be supported by, for example, a bush instead of the first rack and pinion mechanism 24.
In each of the above-described embodiments, as the steering-side actuator 31, for example, a steering-side motor 33 disposed on the same axis as the rack shaft 22, a steering-side motor 33 disposed parallel to the rack shaft 22, etc. It 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 unit 3 and the steered unit 5 are mechanically separated. Not limited to this, a steer-by-wire steering device that can mechanically connect and disconnect the steering unit 3 and the steered unit 5 with a clutch may be used.

  For example, in the example shown in FIG. 10, a clutch 301 is provided between the steering unit 3 and the steered unit 5. The clutch 301 is connected to the steering shaft 12 via an input side intermediate shaft 302 fixed to the input side element, and is connected to the first pinion shaft 21 via an output side intermediate shaft 303 fixed to the output side element. It is connected to. Then, when the clutch 301 is released by the control signal from the steering control device 1, the steering device 2 is in the steer-by-wire mode, and when the clutch 301 is in the engaged state, the steering device 2 is in the electric power steering mode. .

  DESCRIPTION OF SYMBOLS 1 ... Steering control apparatus, 2 ... Steering device, 3 ... Steering part, 4 ... Steering wheel, 5 ... Steering part, 11 ... Steering wheel, 12 ... Steering shaft, 13 ... Steering side actuator, 14 ... Steering side motor, 51 ... Steering side control part (control part) 62 ... Input torque basic component calculation part 63 ... Reaction force component calculation part 64 ... Target steering angle calculation part 65 ... Target reaction force torque calculation part 81 ... Road surface axial force calculation Part (axial force calculating part), 82 ... ideal axial force calculating part (axial force calculating part), 83 ... distributed axial force calculating part, 88 ... distributed axial force adjusting part, 91 ... vehicle state quantity axial force calculating part (axial force) Calculation unit), 92 ... Grip state quantity calculation unit, 101 ... Distribution adjustment gain calculation unit, 104 ... Offset value calculation unit, 105 ... Non-steering gain calculation unit, 111 ... Torque command value calculation unit, 112 ... Torque F / B control , 121... Target steering corresponding angle calculation unit Fd ... Distribution axial force, Fer ... Road surface axial force, Fi ... Ideal axial force, Fir ... Reaction force component, Fyr ... Vehicle state quantity axial force, Gr ... Grip state quantity, Kaa ... Distribution adjustment gain, Kns ... Non-steering gain, LA ... Lateral acceleration, Of ... Offset value, Tb * ... Input torque basic component, Tc ... Drive torque, Th ... Steering torque, Th * ... Torque command value, Tin * ... Input torque, Ts * ... Target reaction torque, Tt * ... target steering torque, V ... vehicle speed, γ ... yaw rate, θh ... steering angle, θp ... steering response angle, θh * ... target steering angle, θp * ... target steering response angle.

Claims (8)

A steering device and a steering device having a structure in which a steered portion that steers steered wheels according to steering input to the steered portion is mechanically separated or mechanically connectable / disconnectable is a control target,
A control unit that controls the operation of a steering side motor that applies a steering reaction force that is a force against steering input to the steering unit;
The controller is
A plurality of axial force calculation units that calculate a plurality of types of axial forces acting on the steered shaft to which the steered wheels are coupled, based on different state quantities;
A distributed axial force calculation unit that calculates a distributed axial force by adding the plurality of types of axial forces at a distribution ratio set individually;
A grip state quantity computing unit that computes a grip state quantity based on the plurality of types of axial forces;
A distributed axial force adjusting unit that adjusts the distributed axial force based on the grip state quantity;
A target steering angle calculation unit that calculates a target steering angle that is a target value of a steering angle of a steering wheel coupled to the steering unit in consideration of the adjusted distribution axial force adjusted by the distribution axial force adjustment unit; Prepared,
A steering control device that calculates a target reaction force torque that is a target value of the steering reaction force based on execution of angle feedback control that causes the steering angle to follow the target steering angle. A steering device and a steering device having a structure in which a steered portion that steers steered wheels according to steering input to the steered portion is mechanically separated or mechanically connectable / disconnectable is a control target,
A control unit that controls the operation of a steering side motor that applies a steering reaction force that is a force against steering input to the steering unit;
The controller is
A plurality of axial force calculation units that calculate a plurality of types of axial forces acting on the steered shaft to which the steered wheels are coupled, based on different state quantities;
A distributed axial force calculation unit that calculates a distributed axial force by adding the plurality of types of axial forces at a distribution ratio set individually;
A grip state quantity computing unit that computes a grip state quantity based on the plurality of types of axial forces;
A distributed axial force adjusting unit that adjusts the distributed axial force based on the grip state quantity;
A steering control device that calculates a target reaction force torque that is a target value of the steering reaction force based on a steering torque applied to the steering unit and an adjusted distribution axial force adjusted by the distribution axial force adjustment unit. A steering device and a steering device having a structure in which a steered portion that steers steered wheels according to steering input to the steered portion is mechanically separated or mechanically connectable / disconnectable is a control target,
A control unit that controls the operation of a steering side motor that applies a steering reaction force that is a force against steering input to the steering unit;
The controller is
A plurality of axial force calculation units that calculate a plurality of types of axial forces acting on the steered shaft to which the steered wheels are coupled, based on different state quantities;
A distributed axial force calculation unit that calculates a distributed axial force by adding the plurality of types of axial forces at a distribution ratio set individually;
A grip state quantity computing unit that computes a grip state quantity based on the plurality of types of axial forces;
A distributed axial force adjusting unit that adjusts the distributed axial force based on the grip state quantity;
A steering control device that calculates a target reaction force torque that is a target value of the steering reaction force based on the adjusted distribution axial force adjusted by the distribution axial force adjustment unit. In the steering control device according to any one of claims 1 to 3,
The distribution axial force adjustment unit includes a distribution adjustment gain calculation unit that calculates a distribution adjustment gain by which the distribution axial force is multiplied,
The distribution adjustment gain calculation unit is a steering control device that changes the distribution adjustment gain based on the grip state quantity. The steering control device according to claim 4, wherein
The distribution adjustment gain calculation unit is a steering control device that changes the distribution adjustment gain according to a vehicle speed. In the steering control device according to any one of claims 1 to 5,
The distribution axial force adjustment unit includes an offset value calculation unit that calculates an offset value to be added to the distribution axial force,
The said offset value calculating part is a steering control apparatus which changes the said offset value based on the said grip state quantity. The steering control device according to claim 6, wherein
The distribution axial force adjustment unit is a steering control device that adjusts the distribution axial force by adding the offset value when the steering unit is in a non-steering state where steering is not input. The steering control device according to claim 6 or 7,
The said offset value calculating part is a steering control apparatus which changes the said offset value according to a vehicle speed.