JP2019209944A - Steering control device - Google Patents

Abstract

To provide a steering control device which can properly transmit a state of a steering device.SOLUTION: A reaction force component calculation part 73 comprises: a base reaction force calculation part 101 for calculating a base reaction force Fd; an end reaction force calculation part 102 for calculating an end reaction force Fie; and an obstacle contact reaction force calculation part 103 for calculating an obstacle contact reaction force Fo. The obstacle contact reaction force calculation part 103 calculates the obstacle contact reaction force Fo on the basis of an obstacle contact gain indicating an approximation degree to a state in which the obstacle contact reaction force Fo should be applied, and a current gain which is foundation of calculating the obstacle contact gain is calculated on the basis of a steering side q axis target current value Iqt*.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a steering control device.

  Conventionally, as a kind of steering device, there is a steer-by-wire type in which power transmission between a steering unit steered by a driver and a steering unit that steers steered wheels according to the steering of the driver is separated. . In such a steering device, the road surface reaction force received by the steered wheels is not mechanically transmitted to the steering wheel. Therefore, a steering control device that controls a steering device of the same type is provided with a steering reaction force in consideration of the road surface information to the steering wheel by a steering side actuator (steering side motor), thereby driving the road surface information. There is something to tell the person.

  For example, in Patent Document 1, 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.

  Further, in the steering control device of the same document, as a reaction force component to be considered when determining the steering reaction force, an end reaction force that alleviates a so-called end impact that the rack end that is the end of the rack shaft hits the rack housing is used. It is added to the distribution axial force. This end reaction force sets a virtual rack end position closer to the neutral position than the actual rack end position where the axial movement of the rack shaft is mechanically restricted, and the target turning angle is greater than the virtual rack end position. Is also given when the steering angle threshold value corresponding to the position near the virtual rack end set on the neutral position side is exceeded. As a result, the incision steering by the driver is restricted before the end contact occurs, and the occurrence of impact is suppressed.

JP 2017-165219 A

  By the way, in recent years, in such a steering control device, it has been required to more appropriately convey the state of the steering device by applying a steering reaction force. For this reason, even if the configuration of the above-mentioned Patent Document 1 is adopted, it cannot be said that the required level is reached yet, and in addition to the situation where the steering is performed to the vicinity of the rack end, the situation of the steering device is appropriately communicated. There was a need to create new technologies that could do this.

  An object of the present invention is to provide a steering control device capable of appropriately transmitting the state of the steering device.

  A steering control device that solves the above problems controls a steering device having a structure in which power transmission between a steering unit and a steered unit that steers steered wheels according to steering input to the steering unit is separated. A steering-side control unit that controls the operation of a steering-side motor that applies a steering reaction force that resists steering input to the steering unit, and a steering force that is a force that steers the steered wheels. A steered side control unit that controls the operation of the steered side motor to be applied, and the steered side control unit is a target turning that is a target value of the rotation angle of the rotating shaft that can be converted into the steered angle of the steered wheel A steered side target that calculates a steered side target current value that is a target value of a drive current supplied to the steered side motor based on execution of angle feedback control that causes the steered corresponding angle to follow the actual steered angle. Based on the current value calculation unit and the value indicating the driving state of the steered side motor A guard processing unit that limits the absolute value of the steered-side target current value to a predetermined limit value or less, and controls the operation of the steered-side motor based on the restricted steered-side target current value after the restriction. The steering-side control unit calculates an obstacle contact reaction force that increases the steering reaction force when it is determined that the steered wheel is hitting an obstacle by turning. A calculation unit that calculates a target reaction force torque that is a target value of the steering reaction force in consideration of the obstacle contact reaction force, and the obstacle contact reaction force calculation unit includes at least the steering It is determined based on the side target current value whether or not the steered wheel is hitting an obstacle by steering.

  According to the above configuration, since the steering reaction force is calculated in consideration of the obstacle contact reaction force, it is possible to inform the driver of the situation in which the steered wheel is hitting the obstacle by turning. Here, in a situation where the steered wheel hits an obstacle by turning, the obstacle becomes an obstacle and cannot be steered even if the steered wheel is driven by driving the steered side motor. Therefore, when determining whether or not the same situation occurs, it is necessary to determine whether or not the steered wheel is to be steered by driving the steered side motor. It is conceivable to use a drive current to be supplied. On the other hand, for example, for the purpose of overheating protection of the steered side motor, the drive current supplied to the steered side motor may be limited. In a situation where the steered wheel hits an obstacle, the steered wheel does not steer and the actual steered response angle cannot follow the target steered response angle. The side motor is likely to overheat. Therefore, in a situation where the steered wheels are hitting an obstacle by turning, it is likely to be necessary to limit the drive current supplied to the steered side motor. When the drive current supplied to the steered side motor is limited in this way, the drive current supplied to the steered side motor is used to determine whether or not the steered wheel is hitting an obstacle by turning. And there is a possibility that the determination cannot be performed accurately. In this regard, in the above configuration, in order to determine whether or not the steered wheel is hitting an obstacle by turning based on at least the steered side target current value before restriction by the guard processing unit, the steered side motor Even in a situation where the drive current to is limited, it can be determined whether the steered wheel is in a situation where it is hitting an obstacle by turning.

  In the steering control device, the guard processing unit reduces the steered side target current value below the predetermined limit value when the drive current to the steered side motor continuously exceeds a predetermined current value for a predetermined time or longer. It is preferable to limit to.

According to the above configuration, when a large drive current is supplied to the steered side motor for a long time, the drive current is limited, so that overheating of the steered side motor can be suitably suppressed.
In the steering control device, the obstacle contact reaction force calculation unit calculates the obstacle contact reaction force based on an obstacle contact gain indicating an approximation degree with respect to a situation where the obstacle contact reaction force should be applied. The current gain serving as the basis for calculating the obstacle contact gain is preferably calculated based on the steered side target current value.

  For example, it is determined whether or not it is a situation to which an obstacle contact reaction force should be applied, and when it is determined that the situation should be applied, the obstacle contact reaction force is set to a value larger than zero and If it is determined that there is no obstacle and the obstacle reaction force is zero, the value of the obstacle application reaction force changes abruptly before and after the determination is established. Therefore, the steering reaction force changes abruptly, which may give the driver a feeling of strangeness. In this regard, according to the above configuration, the obstacle contact reaction force is rapidly changed because the obstacle contact reaction force is calculated based on the gain indicating the degree of approximation to the situation to which the obstacle contact reaction force should be applied. This can be suppressed and a good steering feeling can be realized.

  According to the present invention, it is possible to appropriately convey the status of the steering device.

1 is a schematic configuration diagram of a steer-by-wire steering device according to an embodiment. The block diagram of the steering control apparatus of one Embodiment. The block diagram of the steered side motor control signal output part of one Embodiment. The flowchart which shows the process sequence of the calculation by the guard process part of one Embodiment. The block diagram of the reaction force component calculating part of one Embodiment. The block diagram of the obstacle reaction force calculating part of one Embodiment. (A) is a graph showing the relationship between the steered side target current value and the restricted steered side target current value of one embodiment, and (b) is the drive current supplied to the steered side motor when it hits an obstacle. The graph which shows an example of a change of. The schematic block diagram of the steer-by-wire type steering apparatus of a modification.

Hereinafter, an 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.

  A spiral cable device 21 is connected to the steering wheel 11. The spiral cable device 21 is divided by a first housing 22 fixed to the steering wheel 11, a second housing 23 fixed to the vehicle body, a second housing 23, and the first and second housings 22 and 23. A cylindrical member 24 accommodated in the space formed, and a spiral cable 25 wound around the cylindrical member 24. The steering shaft 12 is inserted through the cylindrical member 24. The spiral cable 25 is an electrical wiring that connects the horn 26 fixed to the steering wheel 11 and the in-vehicle power supply B fixed to the vehicle body. The length of the spiral cable 25 is set to be sufficiently longer than the distance between the horn 26 and the in-vehicle power source B, and the horn is allowed to rotate while the steering wheel 11 is allowed to rotate within a range corresponding to the length. 26 is supplied with electric power.

  The steered portion 5 includes a first pinion shaft 31 as a rotation shaft that can be converted into a steered angle of the steered wheels 4, a rack shaft 32 as a steered shaft connected to the first pinion shaft 31, and a rack shaft 32. And a rack housing 33 for reciprocally moving the housing. The first pinion shaft 31 and the rack shaft 32 are arranged with a predetermined crossing angle. The first pinion teeth 31 a formed on the first pinion shaft 31 and the first rack teeth 32 a formed on the rack shaft 32 The first rack and pinion mechanism 34 is configured by meshing the two. The rack shaft 32 is supported by the first rack and pinion mechanism 34 so that one end in the axial direction thereof can reciprocate. A tie rod 36 is connected to both ends of the rack shaft 32 via a rack end 35 formed of a ball joint, and a tip of the tie rod 36 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 41 via a second pinion shaft 42 that imparts a steered force that steers the steered wheels 4 to the rack shaft 32. The steered side actuator 41 includes a steered side motor 43 serving as a drive source and a steered side speed reducer 44 that decelerates the rotation of the steered side motor 43 and transmits it to the second pinion shaft 42. The second pinion shaft 42 and the rack shaft 32 are arranged with a predetermined crossing angle, and the second pinion teeth 42 a formed on the second pinion shaft 42 and the second rack teeth 32 b formed on the rack shaft 32, The second rack and pinion mechanism 45 is configured by meshing the two. The rack shaft 32 is supported by the second rack and pinion mechanism 45 so that the other end in the axial direction can reciprocate.

  In the steering apparatus 2 configured as described above, the second pinion shaft 42 is rotationally driven by the steered side actuator 41 in accordance with the steering operation by the driver, and this rotation is caused by the second rack and pinion mechanism 45 to rotate the rack shaft 32. 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 a steering actuator 13 (steering motor 14) and a steering actuator 41 (steering motor 43), 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.

  The steering control device 1 is connected to a vehicle speed sensor 51 that detects a vehicle speed SPD of the vehicle and a torque sensor 52 that detects a steering torque Th applied to the steering shaft 12. The torque sensor 52 is provided closer to the steering wheel 11 than the portion of the steering shaft 12 connected to the steering side actuator 13 (steering side speed reducer 15). Further, the steering control device 1 includes a steering-side rotation sensor 53 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 54 that detects the rotation angle θt of the turning-side motor 43 as a relative angle as a detection value indicating the turning amount of 5 is connected. 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 43 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 includes a steering side control unit 61 that outputs a steering side motor control signal Ms, and a steering side that supplies driving power to the steering side motor 14 based on the steering side motor control signal Ms. And a drive circuit 62. The steering-side control unit 61 detects the phase current values Ius, Ivs, Iws of the steering-side motor 14 flowing through the connection line 63 between the steering-side drive circuit 62 and the motor coils of the respective phases of the steering-side motor 14. A current sensor 64 is connected. In FIG. 2, for convenience of explanation, each phase connection line 63 and each phase current sensor 64 are collectively shown as one.

  Further, the steering control device 1 includes a steered side control unit 66 that outputs a steered side motor control signal Mt, and a steered side that supplies driving power to the steered side motor 43 based on the steered side motor control signal Mt. And a drive circuit 67. In the steered side control unit 66, the phase current values Iut, Ivt, etc. of the steered side motor 43 flowing through the connection lines 68 between the steered side drive circuit 67 and the motor coils of the respective phases of the steered side motor 43 are provided. A current sensor 69 for detecting Iwt is connected. In FIG. 2, for convenience of explanation, each phase connection line 68 and each phase current sensor 69 are collectively shown as one. For the steering side drive circuit 62 and the steered side drive circuit 67 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. Then, the steering side motor control signal Ms and the steered side motor control signal Mt are output to the steered side drive circuit 62 and the steered side drive circuit 67, so that each switching element is turned on and off. 14 and the steered side motor 43 are supplied with driving power, respectively. Thereby, the operation of the steering side actuator 13 and the steering side actuator 41 is controlled.

First, the configuration of the steering side control unit 61 will be described.
The steering-side control unit 61 includes the vehicle speed SPD, the steering torque Th, the rotation angle θs, the phase current values Ius, Ivs, Iws, a steering-response angle θp output from the steering-side control unit 66, which will be described later, The q-axis current value Iqt that is the drive current of the side motor 43 and the steered-side q-axis target current value Iqt * as the steered-side target current value that is the target value are input. And the steering side control part 61 produces | generates and outputs the steering side motor control signal Ms based on these each state quantity.

  Specifically, the steering side control unit 61 includes a steering angle calculation unit 71 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 61 also includes an input torque basic component calculation unit 72 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 73 that calculates Fir. The steering side control unit 61 includes a target steering angle calculation unit 74 that calculates a target steering angle θh * based on the steering torque Th, the vehicle speed SPD, the input torque basic component Tb *, and the reaction force component Fir. Further, the steering side control unit 61 includes a target reaction force torque calculation unit 75 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 output unit 76 for outputting a motor control signal Ms.

  The steering angle calculation unit 71 obtains the input rotation angle θs by converting it to an absolute angle including 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 71 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 angle θh calculated in this way is output to the subtractor 78 and the reaction force component calculation unit 73.

  The steering torque Th is input to the input torque basic component calculation unit 72. The input torque basic component calculation unit 72 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 * calculated in this way is input to the target steering angle calculation unit 74 and the target reaction force torque calculation unit 75.

  In addition to the steering torque Th, the vehicle speed SPD, and the input torque basic component Tb *, a reaction force component Fir calculated by a reaction force component calculation unit 73 described later is input to the target steering angle calculation unit 74. The target steering angle calculation unit 74 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 * (1) The target steering angle θh * is calculated using the model (steering model) formula.

Tin * = C · θh * '+ J · θh *''(1)
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 SPD. The target steering angle θh * calculated using the model formula in this way is output to the reaction force component calculation unit 73 in addition to the subtractor 78 and the steered side control unit 66.

  In addition to the input torque basic component Tb *, the target reaction force torque calculator 75 receives an angle deviation Δθs obtained by subtracting the steering angle θh from the target steering angle θh * in the subtractor 78. Then, the target reaction force torque calculation unit 75 is a basis for 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 calculation unit 75 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 output unit 76 receives the rotation angle θs and the phase current values Ius, Ivs, and Iws. The steering side motor control signal output unit 76 of the present embodiment calculates a steering side 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 steering-side d-axis target current value Ids * on the d-axis is basically set to zero. The steering side motor control signal output unit 76 generates (calculates) the steering side motor control signal Ms to be output to the steering side drive circuit 62 by executing current feedback control in the d / q coordinate system.

  Specifically, the steering-side motor control signal output unit 76 maps the phase current values Ius, Ivs, and Iws on the d / q coordinate based on the rotation angle θs, so that the steering-side motor in the d / q coordinate system. A d-axis current value Ids and a q-axis current value Iqs, which are 14 actual current values, are calculated. The steering-side motor control signal output unit 76 follows the d-axis current value Ids to follow the steering-side d-axis target current value Ids *, and follows the q-axis current value Iqs to the steering-side q-axis target current value Iqs *. In order to achieve this, a target voltage value is calculated based on each current deviation on the d-axis and the q-axis, and a steering side motor control signal Ms having a duty ratio based on the target voltage value is generated. When the steering side motor control signal Ms calculated in this way is output to the steering side drive circuit 62, 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 66 will be described.
The turning side control unit 66 receives the rotation angle θt, the target steering angle θh *, and the phase current values Iut, Ivt, Iwt of the turning side motor 43. Then, the steered side control unit 66 generates and outputs a steered side motor control signal Mt based on these state quantities.

  Specifically, the steered side control unit 66 includes a steered corresponding angle calculating unit 81 that calculates a steered corresponding angle θp corresponding to the rotation angle (pinion angle) of the first pinion shaft 31. Further, the steered side control unit 66 is based on the target turning torque calculating unit 82 that calculates the target turning torque Tt * based on the turning corresponding angle θp and the target steering angle θh *, and the target turning torque Tt *. And a steered side motor control signal output unit 83 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 corresponding angle calculation unit 81 obtains the input rotation angle θt by converting it to an absolute angle by counting the number of rotations of the turning side motor 43 from a neutral position where the vehicle goes straight, for example. Then, the turning corresponding angle calculation unit 81 converts the rotation angle converted into the absolute angle based on the rotation speed ratio of the steering reduction gear 44 and the rotation speed ratio of the first and second rack and pinion mechanisms 34 and 45. 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 31 is assumed to be connected to the steering shaft 12. The steering corresponding angle θp calculated in this way is output to the subtractor 84 and the reaction force component calculation unit 73. In addition to the steering response angle θp, the target steering angle θh * (target steering response angle) is input to the subtractor 84.

  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 84 is input to the target steering torque calculation unit 82. Then, the target turning torque calculation unit 82 calculates the turning force applied by the turning side motor 43 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 82 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 output unit 83 receives the rotation angle θt and the phase current values Iut, Ivt, Iwt. The steered side motor control signal output unit 83 calculates the steered side q axis target current value Iqt * on the q axis in the d / q coordinate system based on the target steered torque Tt *. The steered side motor control signal output unit 83 limits the absolute value of the steered side q-axis target current value Iqt * to a predetermined limit value Ilim or less based on the driving state of the steered side motor 43. The predetermined limit value Ilim is smaller than the rated current Ir set in advance as the maximum value of the drive current that can be supplied to the steered side motor 43, and the steered wheel 4 can be smoothly moved if it does not hit an obstacle such as a curb. It is a value that can be steered, and is set based on experiments and the like in advance. In the present embodiment, the steered side d-axis target current value Idt * on the d-axis is basically set to zero. The steered side motor control signal output unit 83 generates (calculates) a steered side motor control signal Mt to be output to the steered side drive circuit 67 by executing current feedback control in the d / q coordinate system. To do.

  Specifically, as shown in FIG. 3, the steered side motor control signal output unit 83 includes a steered side target current value calculation unit 91 that calculates the steered side target current values Idt * and Iqt *, and a steered side target. And a guard processing unit 92 that limits the absolute values of the current values Idt * and Iqt * to be small.

  A target turning torque Tt * is input to the turning target current value calculation unit 91. The steered side target current value calculation unit 91 calculates the steered side q-axis target current value Iqt * based on the target steered torque Tt *. Specifically, the steered side target current value calculating unit 91 calculates a steered side q-axis target current value Iqt * having a larger absolute value based on an increase in the absolute value of the target steered torque Tt *. The steered side q-axis target current value Iqt * calculated in this way is output to the guard processing unit 92 and the reaction force component calculation unit 73. Further, the steered side target current value calculating unit 91 outputs the steered side d-axis target current value Idt * indicating zero to the guard processing unit 92.

  The guard processing unit 92 receives the steered-side target current values Idt * and Iqt *, the d-axis current value Idt and the q-axis current value Iqt output from the dq conversion unit 93 described later. The guard processing unit 92 limits the absolute value of the steered-side q-axis target current value Iqt * to a predetermined limit value Ilim or less based on the q-axis current value Iqt that is a value indicating the drive state of the steered-side motor 43. To do.

  Specifically, as shown in the flowchart of FIG. 4, for example, when the guard processing unit 92 acquires various state quantities (step 101), the guard side q-axis target current value Iqt * is limited to a predetermined limit value Ilim or less. It is determined whether or not a restriction flag indicating that it is in a state of being set is set (step 102). Subsequently, if the limit flag is not set (step 102: NO), is the flag set condition in which the absolute value of the q-axis current value Iqt continues for the predetermined time tth or more and becomes the predetermined current value Ith1 or more is satisfied? It is determined whether or not (step 103). In the present embodiment, the predetermined current value Ith1 is set to the same value as the predetermined limit value Ilim. The predetermined time tth is a time at which it can be determined that the turning of the steered wheels 4 is obstructed by the turning of the steered wheels 4 and is set in advance based on experiments or the like. Subsequently, when the flag setting condition is satisfied (step 103: YES), a restriction flag is set (step 104), and the process proceeds to step 105. On the other hand, if the restriction flag is set (step 102: YES), the process directly proceeds to step 105.

  In step 105, the guard processing unit 92 determines whether or not the absolute value of the steered side q-axis target current value Iqt * is larger than a predetermined limit value Ilim. If the absolute value of the steered side q-axis target current value Iqt * is larger than the predetermined limit value Ilim (step 105: YES), the absolute value of the steered side q-axis target current value Iqt * is set to the predetermined limit value. The value limited to Ilim is output as the limited turning side q-axis target current value Iqt ** (step 106). On the other hand, when the absolute value of the steered side q-axis target current value Iqt * is equal to or smaller than the predetermined limit value Ilim (step 105: NO), the limit flag is reset (step 107), and the steered side q-axis target current is set. The value Iqt * is output as it is as the limited turning side q-axis target current value Iqt ** (step 108). When the flag set condition is not satisfied (step 103: NO), the process directly proceeds to step 108, and the steered side q-axis target current value Iqt * is directly used as the limited steered side q-axis target current value Iqt **. Output.

  By performing the guard process in this way, as indicated by a solid line in FIG. 7A, when the absolute value of the steered side q-axis target current value Iqt * is equal to or smaller than the predetermined limit value Ilim, the limit after the limit is set. The steered side q-axis target current value Iqt ** is equal to the steered side q-axis target current value Iqt *. Further, when the absolute value of the steered side q-axis target current value Iqt * is larger than the predetermined limit value Ilim, as shown by a one-dot chain line in FIG. The absolute value is equal to the predetermined limit value Ilim. Since the steered side d-axis target current value Idt * is zero, the guard processing unit 92 sets the steered side d axis target current value Idt * as it is as the limited steered side d axis target current value Idt **. Output.

  As shown in FIG. 3, each phase current value Iut, Ivt, Iwt input to the steered side motor control signal output unit 83 is input to the dq conversion unit 93. The dq converter 93 calculates the d-axis current value Idt and the q-axis current value Iqt by mapping each phase current value Iut, Ivt, Iwt on the dq coordinate based on the rotation angle θt. The d-axis current value Idt is input to the subtractor 94d together with the limited turning side d-axis target current value Idt **, and the q-axis current value Iqt is combined with the limited turning side q-axis target current value Iqt **. Is input. Each of the subtractors 94d and 94q calculates a d-axis current deviation ΔIdt and a q-axis current deviation ΔIqt. The q-axis current value Iqt is also output to the reaction force component calculation unit 73.

  The d-axis current deviation ΔIdt and the q-axis current deviation ΔIqt are input to the corresponding F / B (feedback) control units 95d and 95q, respectively. Each of the F / B control units 95d and 95q is configured so that the d-axis current value Idt and the q-axis current value Iqt, which are actual current values, follow the limited turning-side target current values Idt ** and Iqt **. The d-axis target voltage value Vdt * and the q-axis target voltage value Vqt * are calculated by multiplying the axis current deviation ΔIdt and the q-axis current deviation ΔIqt by a predetermined gain, respectively.

  The d-axis target voltage value Vdt * and the q-axis target voltage value Vqt * are input to the dq inverse conversion unit 96 together with the rotation angle θt. The dq inverse transform unit 96 maps the three-phase target voltage values Vut * and Vvt by mapping the d-axis target voltage value Vdt * and the q-axis target voltage value Vqt * on the three-phase AC coordinates based on the rotation angle θt. *, Vwt * is calculated. Subsequently, these target voltage values Vut *, Vvt *, and Vwt * are input to the PWM conversion unit 97. The PWM converter 97 calculates duty command values αut *, αvt *, αwt * based on the target voltage values Vut *, Vvt *, Vwt *, and outputs them to the control signal generator 98. The control signal generation unit 98 compares the duty command values αut *, αvt *, αwt * with the PWM carrier as a carrier wave such as a triangular wave or a saw wave, and the duty indicated by the duty command values αut *, αvt *, αwt *. A steered side motor control signal Mt having a ratio is generated and output to the steered side drive circuit 67. Thereby, as shown in FIG. 2, the drive electric power according to the steering side motor control signal Mt is output to the steering side motor 43, and the operation | movement is controlled.

Next, the configuration of the reaction force component calculation unit 73 will be described.
The reaction force component calculation unit 73 receives the vehicle speed SPD, the steering angle θh, the steering response angle θp, the target steering angle θh *, the q-axis current value Iqt, and the steering-side q-axis target current value Iqt *. The reaction force component calculation unit 73 calculates the reaction force component Fir based on these state quantities and outputs the calculated reaction force component Fir to the target steering angle calculation unit 74.

  As shown in FIG. 5, the reaction force component calculation unit 73 includes a base reaction force calculation unit 101, an end reaction force calculation unit 102, and an obstacle contact reaction force calculation unit 103. The base reaction force calculation unit 101 calculates a base reaction force Fd corresponding to the axial force of the rack shaft 32. When the absolute value of the steering angle θh of the steering wheel 11 approaches the limit steering angle, the end reaction force calculation unit 102 calculates an end reaction force Fie that is a reaction force that resists further turning steering. The obstacle contact reaction force calculation unit 103 calculates an obstacle contact reaction force Fo that resists further incision steering when the steered wheel 4 hits an obstacle such as a curb due to turning. . Then, the reaction force component calculation unit 73 outputs a value obtained by adding the reaction force having the largest absolute value of the end reaction force Fie and the obstacle reaction force Fo to the base reaction force Fd as the reaction force component Fir. .

  Specifically, the base reaction force calculation unit 101 includes a road surface axial force calculation unit 111 that calculates the road surface axial force Fer and an ideal axial force calculation unit 112 that calculates the ideal axial force Fib. The road surface axial force Fer and the ideal axial force Fib are calculated by a torque dimension (N · m). Further, the reaction force component calculation unit 73 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. The distributed axial force calculation unit 113 is provided that calculates the distributed axial force distributed in step 1 as the base reaction force Fd.

  A target steering angle θh * (target steering response angle) is input to the ideal axial force calculation unit 112. The ideal axial force calculation unit 112 is an ideal value of the axial force acting on the steered wheels 4 (transmitted force transmitted to the steered wheels 4), and an 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 112 calculates the absolute value of the ideal axial force Fib as the absolute value of the target steering angle θh * increases. The ideal axial force Fib thus calculated is output to the multiplier 114.

  The q-axis current value Iqt of the steered side motor 43 is input to the road surface axial force calculation unit 111. The road surface axial force calculation unit 111 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 111 determines that the torque applied to the rack shaft 32 by the steered side motor 43 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 thus calculated is output to the multiplier 115.

  In addition to the vehicle speed SPD, the road surface axial force Fer and the ideal axial force Fib are input to the distributed axial force calculation unit 113. The distribution axial force calculation unit 113 includes a distribution gain calculation unit 116 that calculates distribution gains Gib and Ger that are distribution ratios for distributing the ideal axial force Fib and the road surface axial force Fer based on the vehicle speed SPD. Yes. The distribution gain calculation unit 116 of the present embodiment includes a map that defines the relationship between the vehicle speed SPD and the distribution gain Gib and Ger, and calculates the distribution gain Gib and Ger according to the vehicle speed SPD by referring to the map. To do. The distribution gain Gib is smaller when the vehicle speed SPD is larger than when it is small, and the distribution gain Ger is larger when the vehicle speed SPD 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 thus calculated is output to the multiplier 114, and the distribution gain Ger is output to the multiplier 115.

  The distribution axial force calculation unit 113 multiplies the ideal axial force Fib by the distribution gain Gib in the multiplier 114, multiplies the road surface axial force Fer by the distribution gain Ger in the multiplier 115, and adds these values in the adder 117. In addition, a base reaction force Fd (distributed axial force) is calculated. The base reaction force Fd calculated in this way is output to the adder 105.

  A target steering angle θh * (target steering response angle) is input to the end reaction force calculation unit 102. The end reaction force calculation unit 102 includes a map that defines the relationship between the target steering angle θh * and the end reaction force Fie. By referring to the map, the end reaction force Fie corresponding to the target steering angle θh * is obtained. Calculate. In the map, a threshold angle θie is set. When the absolute value of the target steering angle θh * is less than or equal to the threshold angle θie, zero is calculated as the end reaction force Fie, and the target steering angle θh * is the threshold angle θie. Is exceeded, the end reaction force Fie whose absolute value is greater than zero is calculated. The end reaction force Fie calculated in this way is output to the reaction force selection unit 106. It should be noted that the end reaction force Fie is set to have a large absolute value such that when the target steering angle θh * increases to some extent beyond the threshold angle θie, further infeed steering cannot be performed by human force.

  Here, in the present embodiment, in relation to the mechanical configuration of the steered portion 5, a mechanical rack end position in which the rack shaft 32 is restricted from moving in the axial direction by the rack end 35 coming into contact with the rack housing 33. The virtual rack end position is set closer to the neutral position side. Then, the threshold angle θie is set to the value of 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 further than the virtual rack end position. Further, the threshold angle θie (steering response angle θp near the virtual rack end) is a mechanical configuration with the steering unit 3 when it is assumed that the steering unit 3 and the steering unit 5 are connected. In relation, the steering angle θh at the steering end position of the steering wheel 11 allowed to the maximum by the spiral cable device 21 is set to the neutral position side. That is, in the steering device 2 of the present embodiment, the position near the virtual rack end is set as the steering angle limit position of the steered portion 5, and the steering end position is set as the steering angle limit position of the steering portion 3. When it is assumed that the first pinion shaft 31 is connected to the steering shaft 12, the steered portion 5 (the steered wheels 4) first reaches the steering angle limit position. The threshold angle θie corresponds to the steering angle threshold set according to the steering device 2.

  In addition to the steering side q-axis target current value Iqt *, the obstacle contact reaction force calculation unit 103 includes an angle deviation Δθx obtained by subtracting the steering corresponding angle θp from the steering angle θh in the subtractor 107, and the steering corresponding angle θp. The turning speed ωt obtained by differentiating is inputted. The obstacle contact reaction force calculation unit 103 according to the present embodiment calculates an obstacle contact gain Go indicating the degree of approximation to the situation to which the obstacle contact reaction force Fo should be applied based on these state quantities, and the obstacle contact reaction force Fo. An obstacle contact reaction force Fo is calculated based on the gain Go.

  Specifically, as shown in FIG. 6, the obstacle application reaction force calculation unit 103 is based on the current gain calculation unit 121 that calculates the current gain Goi based on the steered-side q-axis target current value Iqt *, and the angle deviation Δθx. An angle gain calculation unit 122 that calculates the angle gain Goa and a speed gain calculation unit 123 that calculates a speed gain Gos based on the turning speed ωt are provided.

  The steered-side q-axis target current value Iqt * is input to the current gain calculation unit 121. The current gain calculation unit 121 includes a map that defines the relationship between the absolute value of the steered-side q-axis target current value Iqt * and the current gain Goi. By referring to this map, the steered-side q-axis target current The current gain Goi corresponding to the value Iqt * is calculated. This map shows that the current gain Goi is “0” when the absolute value of the steered-side q-axis target current value Iqt * is zero, and is proportional to the increase in the absolute value of the steered-side q-axis target current value Iqt *. The current gain Goi increases. The current gain Goi is set to “1” when the absolute value of the steered side q-axis target current value Iqt * becomes larger than the current threshold Ith2. That is, in the present embodiment, as one of the conditions for determining that the steered wheels 4 are approximated to the situation where the steered wheels 4 are hitting an obstacle, the fact that the steered wheels 4 are to be steered is adopted. It is determined that the larger the absolute value of the q-axis target current value Iqt * is, the closer the situation is to the situation where the steered wheel 4 is hitting an obstacle by turning. The current threshold value Ith2 is a current value that can be used to steer the steered wheels 4 when supplied to the steered side motor 43 on a normal road surface, and is set in advance by a test or the like. The current gain Goi calculated in this way is input to the multiplier 124.

  An angle deviation Δθx is input to the angle gain calculation unit 122. The angle gain calculation unit 122 includes a map that defines the relationship between the absolute value of the angle deviation Δθx and the angle gain Goa, and calculates the angle gain Goa according to the angle deviation Δθx by referring to the map. In this map, when the absolute value of the angle deviation Δθx is zero, the angle gain Goa becomes “0”, and the angular gain Goa increases in proportion to the increase in the absolute value of the angle deviation Δθx. When the absolute value of the angle deviation Δθx becomes larger than the angle deviation threshold value Δθth, the angle gain Goa is set to “1”. That is, in this embodiment, as one of the conditions for determining that the steered wheels 4 are approximated to the situation where the steered wheels 4 are hitting an obstacle, the deviation between the steering angle θh and the steering corresponding angle θp is large. It is determined that the larger the absolute value of the angle deviation Δθx is, the closer it is to the situation where the steered wheels 4 are hitting an obstacle by turning. Note that the angle deviation threshold Δθth is an angle at which the steering angle θh and the steering response angle θp can be regarded as deviated even in consideration of sensor noise or the like, and is set in advance by a test or the like. The angle gain Goa calculated in this way is input to the multiplier 124.

  The speed gain calculation unit 123 receives the turning speed ωt. The speed gain calculation unit 123 includes a map that defines the relationship between the absolute value of the turning speed ωt and the speed gain Gos, and calculates the speed gain Gos corresponding to the turning speed ωt by referring to the map. . In this map, when the absolute value of the turning speed ωt is zero, the speed gain Gos becomes “1”, and the speed gain Gos decreases in proportion to the increase in the absolute value of the turning speed ωt. The speed gain Gos is set to “0” when the absolute value of the steering speed ωt becomes larger than the speed threshold ωth. That is, in this embodiment, as one of the conditions for determining that the steered wheels 4 are approximated to the situation where the steered wheels 4 are hitting an obstacle, the fact that the steered speed ωt is low is adopted, and the absolute value of the steered speed ωt is adopted. It is determined that the lower the value is, the closer to the situation where the steered wheel 4 is hitting an obstacle by steering. Note that the speed threshold ωth is a speed at which the steered wheels 4 can be regarded as steered even in consideration of sensor noise and the like, and is set in advance by a test or the like. The speed gain Gos calculated in this way is input to the multiplier 124.

  The obstacle contact reaction force calculation unit 103 multiplies the current gain Goi, the angle gain Goa, and the speed gain Gos in the multiplier 124 to obtain an approximation degree for the situation where the obstacle contact reaction force Fo should be applied. The obstacle hitting gain Go shown is calculated. The obstacle hitting gain Go calculated in this way is output to the reaction force calculation processing unit 125.

  The reaction force calculation processing unit 125 includes a map that defines the relationship between the obstacle contact gain Go and the obstacle contact reaction force Fo. By referring to the map, the obstacle contact according to the obstacle contact gain Go is provided. The reaction force Fo is calculated. In this map, when the obstacle contact gain Go is zero, the obstacle contact reaction force Fo becomes “0”, and the obstacle contact reaction force Fo gradually increases in proportion to the increase in the obstacle contact gain Go. When the obstacle contact gain Go becomes larger than the gain threshold Gth, the obstacle contact reaction force Fo increases rapidly in proportion to the increase in the obstacle contact gain Go. The gain threshold Gth is a magnitude of a gain that can be determined as a situation where the steered wheels 4 are hitting an obstacle by steering, and is set in advance by a test or the like. Further, the obstacle contact reaction force Fo is set to have a large absolute value so that when the obstacle contact gain Go exceeds the gain threshold value Gth to some extent, a further power steering cannot be performed. . Thereby, in the region where the obstacle hitting gain Go is equal to or less than the gain threshold Gth, the reaction force when only the tire portion of the steered wheel 4 hits the obstacle is reproduced by the obstacle hitting reaction force Fo, and the obstacle hitting gain Go In a region where is larger than the gain threshold value Gth, the reaction force when the wheel portion of the steered wheel 4 hits the obstacle is reproduced by the obstacle reaction force Fo. The obstacle contact reaction force Fo thus calculated is output to the reaction force selection unit 106 (see FIG. 3).

  As shown in FIG. 5, in addition to the end reaction force Fie and the obstacle contact reaction force Fo, a steering speed ωh obtained by differentiating the steering angle θh is input to the reaction force selection unit 106. The reaction force selection unit 106 selects a reaction force having a large absolute value from the end reaction force Fie and the obstacle contact reaction force Fo, and a sign (direction) of the reaction force indicated by the steering speed ωh. Is output to the adder 105 as the selected reaction force Fsl. Then, in the adder 105, the reaction force component calculation unit 73 calculates a value obtained by adding the selected reaction force Fsl to the base reaction force Fd as a reaction force component Fir, and the target steering angle calculation unit 74 (see FIG. 2). Output.

Next, the operation when the steered wheel 4 hits an obstacle such as a curb by turning will be described.
For example, as shown in FIG. 7B, when the steering is steered to the left or right, the steered wheels 4 are obstructed by turning at the time t1 when the steering angle θh is on the neutral position side of the threshold angle θie. Assume that no more steering is possible. In this case, since the steerable wheels 4 cannot be steered, the actual steering response angle θp cannot follow the target steering angle θh * (target steering response angle), and therefore the steered side q-axis target current value Iqt * (restriction) The steered side q-axis target current value Iqt **) increases. As shown in the figure, the q-axis current value Iqt exceeds the predetermined limit value Ilim and further increases to the rated current Ir. Further, as the steered side q-axis target current value Iqt * increases, the current gain Goi (obstacle application gain Go) increases and the obstacle application reaction force Fo increases. As a result, an increase in the steering reaction force informs the driver that the steered wheels 4 have hit an obstacle due to the steer.

  Here, when the driver continues to steer in the same direction even if the steering reaction force increases, as described above, when the predetermined time tth elapses after the q-axis current value Iqt exceeds the predetermined limit value Ilim, As shown in FIG. 7A, the absolute value of the limit turning side q-axis target current value Iqt ** becomes equal to the predetermined limit value Ilim. As a result, as shown in FIG. 7B, after time t2 when the restriction of the q-axis current value Iqt is started, the q-axis current value Iqt becomes substantially equal to the predetermined restriction value Ilim, and the turning-side motor 43 Overheating is suppressed. At this time, since the current gain Goi is calculated based on the steered-side q-axis target current value Iqt * as described above, the obstacle reaction force Fo changes before and after the q-axis current value Iqt is limited. Therefore, it is possible to prevent the driver from feeling uncomfortable and to accurately notify the driver that the steered wheels 4 are in a situation where they are hitting an obstacle by turning.

The operation and effect of this embodiment will be described.
(1) The steering-side control unit 61 calculates an obstacle contact reaction force Fo that increases the steering reaction force when it is determined that the steered wheel 4 is hitting an obstacle by turning. Since the calculation unit 103 is provided and the target reaction force torque Ts * is calculated in consideration of the obstacle contact reaction force Fo, it is possible to inform the driver of the situation where the steered wheels 4 are hitting the obstacle by turning. Then, based on the steered side q-axis target current value Iqt * before the restriction by the guard processing unit 92, the obstacle contact reaction force computing unit 103 determines whether or not the steered wheels 4 are hitting the obstacle by turning. Therefore, even when the q-axis current value Iqt, which is the drive current to the steered side motor 43, is limited, it can be determined whether the steered wheel 4 is hitting an obstacle by turning.

  (2) The guard processing unit 92 limits the q-axis current value Iqt when the q-axis current value Iqt of the steered side motor 43 continues to be equal to or greater than the predetermined current value Ith1 for a predetermined time tth or longer. When large driving power is supplied over time, overheating of the steered side motor 43 can be suitably suppressed.

  (3) For example, it is determined whether or not it is a situation where an obstacle contact reaction force Fo should be applied, and when it is determined that the situation should be applied, the obstacle contact reaction force Fo is set to a value greater than zero. If it is not determined that the situation should be given, if the obstacle reaction force Fo is zero, the value of the obstacle reaction force Fo changes abruptly before and after the determination is established. Therefore, the steering reaction force changes abruptly, which may give the driver a feeling of strangeness. In this respect, in the present embodiment, the obstacle contact reaction force calculation unit 103 calculates the obstacle contact reaction force Fo based on the obstacle contact gain Go, so that the obstacle contact reaction force Fo changes rapidly. It can be suppressed and a good steering feeling can be realized.

  (4) The steering-side control unit 61 has the largest absolute value selected by the reaction force selection unit 106 from the end reaction force Fie and the obstacle contact reaction force Fo as the reaction force to be added to the base reaction force Fd. Therefore, it is possible to suppress an excessive steering reaction force.

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 above embodiment, the predetermined current value Ith1 may be set to a value different from the predetermined limit value Ilim.

  In the above embodiment, when the absolute value of the steered-side q-axis target current value Iqt * is equal to or smaller than the predetermined limit value Ilim, the limit flag is immediately reset. The limit flag may be reset when a state in which the absolute value of the target current value Iqt * is equal to or less than the predetermined limit value Ilim continues for a certain period of time.

  In the above embodiment, the q-axis current value Iqt is limited when the q-axis current value Iqt of the steered side motor 43 continues for the predetermined time tth or more and becomes the predetermined current value Ith1 or more. However, the present invention is not limited to this, for example, a temperature sensor that detects the temperature of the steered side motor 43 may be provided, and the q-axis current value Iqt may be limited when the output value of the temperature sensor exceeds the temperature threshold, The conditions for starting the limitation of the q-axis current value Iqt can be changed as appropriate.

In the embodiment described above, the reaction force component calculation unit 73 may include an additional reaction force calculation unit that calculates an additional reaction force for transmitting other situations in addition to the obstacle contact reaction force calculation unit 103.
In the above embodiment, the obstacle gain G0 is obtained by multiplying the current gain Goi based on the steering side q-axis target current value Iqt *, the angle gain Goa based on the angle deviation Δθx, and the speed gain Gos based on the steering speed ωt. Was calculated. However, the present invention is not limited to this, and if the obstacle contact gain Go is based on at least the current gain Goi (steering side q-axis target current value Iqt *), the angle gain Goa (angle deviation) is calculated in the obstacle contact gain Go. At least one of (Δθx) and speed gain Gos (steering speed ωt) may not be used.

  In the above embodiment, the obstacle contact reaction force calculation unit 103 calculates the obstacle contact reaction force Fo based on the obstacle contact gain Go. However, the present invention is not limited to this, and at least if the steered side q-axis target current value Iqt * is used, it is alternatively determined whether or not the obstacle hitting reaction force Fo should be applied. The obstacle reaction force Fo may be calculated accordingly.

  In the above embodiment, 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 the above embodiment, 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, and other methods such as calculation based on a change in the yaw rate γ or the vehicle speed SPD may be used. Further, for example, a pressure sensor or the like that can detect the axial force may be provided on the rack shaft 32, and the detection result may be used as the road surface axial force Fer.

  In the above embodiment, the ideal axial force Fib is calculated based on the target steering angle θh * (target steering response angle), but is not limited thereto, and may be calculated based on the steering angle θh, for example. The calculation may be performed by other methods such as adding other parameters such as the torque Th and the vehicle speed SPD.

  In the above embodiment, the distribution axial force calculation unit 113 may calculate the distribution gains Gib and Ger in consideration of parameters other than the vehicle speed SPD. 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 113 includes a plurality of maps having different tendencies with respect to the vehicle speed SPD for each drive mode and calculates the distribution gains Gib and Ger by referring to the maps.

  In the above embodiment, the target steering angle calculation unit 74 sets the 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 SPD. If it is set based on the steering torque Th, the input torque basic component Tb *, and the reaction force component Fir, for example, the vehicle speed SPD may not be used.

  In the above-described embodiment, the target steering angle calculation unit 74 uses the model formula that is modeled by adding a so-called spring term using a spring coefficient K determined by specifications such as suspension and wheel alignment. θh * may be calculated.

  In the above embodiment, the target reaction force torque calculation unit 75 calculates the target reaction force torque Ts * by adding the input torque basic component Tb * to the basic reaction force torque. The basic reaction force torque may be directly calculated as the target reaction force torque Ts * without adding Tb *.

In the above embodiment, instead of the first rack and pinion mechanism 34, the rack shaft 32 may be supported by a bush or the like, for example.
In the above embodiment, as the steered side actuator 41, for example, one that arranges the steered side motor 43 on the same axis as the rack shaft 32 or one that arranges the steered side motor 43 in parallel with the rack shaft 32 is used. May be.

  In the above embodiment, 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. Alternatively, 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. 8, a clutch 201 is provided between the steering unit 3 and the steered unit 5. The clutch 201 is connected to the steering shaft 12 via an input side intermediate shaft 202 fixed to the input side element, and is connected to the first pinion shaft 31 via an output side intermediate shaft 203 fixed to the output side element. It is connected to. When the clutch 201 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 201 is in the engaged state, the steering device 2 is in the electric power steering mode. .

  Fd: Base reaction force, Fsl: Selection reaction force, Go: Obstacle contact gain, Fie: End reaction force, Fo: Obstacle contact reaction force, Goa ... Angular gain, Goi ... Current gain, Gos ... Speed gain, Ilim ... Predetermined limit value, Ith1 ... predetermined current value, Idt ... d-axis current value, Iqt ... q-axis current value, Idt * ... steering side d-axis target current value, Iqt * ... steering side q-axis target current value, Idt * * ... Limited steering side d-axis target current value, Iqt ** ... Limited steering side q-axis target current value, Ts * ... Target reaction force torque, Tt * ... Target steering torque, tth ... Predetermined time, θh ... Steering Angle, θp: Steering response angle, θh *: Target steering angle, 1 ... Steering control device, 2 ... Steering device, 3 ... Steering unit, 4 ... Steering wheel, 5 ... Steering unit, 14 ... Steering side motor, 31 ... 1st pinion shaft (rotating shaft), 43 ... Steering side motor, 61 ... Steering side control unit, 66 ... Steering side control unit, 75 ... Target reaction force torque calculation unit, 82 ... Target steering torque Calculation unit, 83 ... Steering side motor control signal output unit, 91 ... Steering side target current value calculation unit, 92 ... Guard processing unit, 103 ... Obstacle contact reaction force calculation unit, 121 ... Current gain calculation unit, 122 ... Angle gain calculation unit, 123... Speed gain calculation unit.

Claims (3)

A steering device having a structure in which power transmission between a steering unit and a steered unit that steers steered wheels according to steering input to the steering unit is separated is a control target,
A steering-side control unit that controls the operation of a steering-side motor that applies a steering reaction force that is a force that resists steering input to the steering unit;
A steered side control unit that controls the operation of a steered side motor that gives a steered force that is a force to steer the steered wheels, and
The steered side control unit
Based on the execution of angle feedback control for causing the actual steering response angle to follow the target steering response angle, which is the target value of the rotation angle of the rotary shaft that can be converted into the steering angle of the steered wheels, the steering side motor A steered side target current value computing unit that computes a steered side target current value that is a target value of the drive current supplied to
A guard processing unit that limits the absolute value of the steered side target current value to a predetermined limit value or less based on a value indicating a driving state of the steered side motor;
Control the operation of the steered side motor based on the limited steered side target current value after the limit,
The steering-side control unit includes an obstacle contact reaction force calculation unit that calculates an obstacle contact reaction force that increases the steering reaction force when it is determined that the steered wheel is hitting an obstacle by turning. Provided, calculating a target reaction torque that is a target value of the steering reaction force in consideration of the obstacle application reaction force,
The obstacle control reaction force calculation unit determines whether or not the steered wheel is hitting an obstacle by turning based on at least the steered side target current value. The steering control device according to claim 1, wherein
The guard processing unit restricts the steered side target current value to the predetermined limit value or less when the drive current to the steered side motor continues for a predetermined time or more and becomes a predetermined current value or more. . The steering control device according to claim 1 or 2,
The obstacle contact reaction force calculation unit is configured to calculate the obstacle contact reaction force based on an obstacle contact gain indicating an approximation degree with respect to a situation where an obstacle contact reaction force should be applied.
A steering control device in which a current gain serving as a basis for calculating the obstacle application gain is calculated based on the steered side target current value.