JP2019127217A - Steering control device for controlling steer-by-wire vehicular steering device - Google Patents

Abstract

To provide a steering control device for controlling a steer-by-wire vehicular steering device that sets reaction force with distribution of estimated axial force and ideal axial force and that is capable of conveying collision with an obstacle to a steering person when a steering wheel collides with an obstacle.SOLUTION: A steering control device has determination conditions that a steering angle deviation θpΔ between a target steering angle θp* and a steering angle θp exceeds a collision determination deviation threshold Δθpr, and that a current iq (steering current) of a q-axis exceeds a collision determination current threshold ir. The steering control device has a determination unit M40 which determines that a steering wheel collided with a curb stone when both determination conditions are satisfied. After the determination unit M40 determines that the steering wheel collided with the curb stone, the control device switches ideal axial force Fib calculated from a target steering angle to estimated axial force Fer as axial force transmitted to a rack axis, and calculates reaction force.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a steering control apparatus that controls a steer-by-wire type vehicle steering apparatus.

  In the steer-by-wire vehicle steering device, the transmission of power between the steered wheels and the steering is mechanically separated, so that a reaction force is applied to the steering by a reaction force actuator (Patent Literature). 1, Patent Document 2, Patent Document 3).

  In Patent Document 1, the torque of the reaction force is determined based on the deviation between the position of the turning shaft that operates the turning wheels and the target position of the turning shaft calculated based on the rotation angle of the steering. . And in patent document 1, at the time of the curbing of a turning wheel, based on that the said deviation becoming large, the said reaction force is enlarged and the curbing collision is transmitted to a steering person.

  In Patent Document 2, the estimated disturbance equivalent is added to the command value of the steering reaction force calculated based on the difference between the target turning angle and the actual turning angle. In Patent Document 2, when it is determined that the steered wheel has collided with an obstacle such as a curbstone, the steering reaction force is increased in a pulse manner to notify the steering person that the steered wheel has collided with the obstacle. .

  In Patent Document 3, focusing on the axial force acting on the steered shaft, the ideal axial force calculated from the target turning angle obtained based on the steering angle and the estimated axial force calculated from the road surface information are respectively distributed By doing so, the reaction force is determined.

JP-A-2006-298223, FIG. 5-A, FIG. 6, paragraph 0031 Japanese Patent Laying-Open No. 2005-96725, paragraph 0075 JP, 2017-165219, A

  By the way, in Patent Document 3, the estimated axial force is calculated based on the turning current as the road surface information of the turning actuator. In the vehicle running state, the ideal axial force is distributed when the steering is near the neutral center, and the estimated axial force is distributed when the steering is cut. Further, in the stop state, the reaction force based on the ideal axial force is transmitted to the steerer in the entire area of the working range of the turning shaft.

  As described above, since the reaction force based on the ideal axial force is partially or entirely used in the vehicle traveling state and the stopping state, the collision with the curb or the like is caused when the curb or the like of the steered wheel collides. There is a risk that they will not be

  An object of the present invention is to provide a steer-by-wire vehicle steering device that sets a reaction force by distributing an estimated axial force and an ideal axial force. It is an object of the present invention to provide a steering control device in which a steer-by-wire type vehicle steering device capable of transmitting a collision of an obstacle to a steerer is controlled.

  In order to solve the above-mentioned problems, a steering control device for which the steer-by-wire vehicle steering device of the present invention is controlled includes a reaction force actuator that applies a reaction force against steering operation, a steered wheel, A steered actuator for steering the steered wheel via a steered shaft under a power cut-off state with respect to a steering, a steered control unit for controlling the steered actuator according to steering of the steering, and the reaction A steering control device for controlling a steer-by-wire type vehicle steering apparatus including a reaction force control unit for calculating a reaction force for controlling a force actuator, wherein the reaction force control unit is a determination condition. And a determination unit for determining an obstacle collision when at least a deviation between the target turning angle and the actual turning angle exceeds a collision determination deviation threshold value, and after this determination, the shaft transmitted to the turning shaft As an ideal axial force for calculating the target turning angle, it is switched to the estimated axial force calculated from the turning current of the steering actuator is for calculating the reaction force.

  According to the above configuration, when the steered wheels collide with an obstacle, the steered wheels cannot be steered by the obstacle, and the actual steered angle becomes constant. On the other hand, since the steer-by-wire does not have mechanical connection between the steered wheels and the steering, if the steering is steered so as to be in the same direction as the steered wheels after the steered wheels collide with the obstacle, the steering Accordingly, the target turning angle is increased and calculated. When the deviation between the target turning angle and the actual turning angle exceeds the collision determination deviation threshold value, the determination unit determines that there is an obstacle collision. After this determination, the reaction force control unit switches the ideal axial force calculated from the target turning angle as the axial force transmitted to the turning shaft to the estimated axial force calculated from the turning current of the turning actuator. And calculating the reaction force.

  Further, the determination unit determines that an obstacle collision is satisfied when all the combined determination conditions are further satisfied, with any one or more of the following (a) to (c) as the determination conditions. Also good.

(A) The turning current exceeds the collision determination current threshold.
(B) | turning angular velocity | <collision determination turning angular velocity threshold, and | target turning angular acceleration | <collision determination target steering angle acceleration threshold.

(C) | estimated axial force | --ideal axial force | exceeds the collision determination axial force difference threshold.
If any one or more combinations of (a) to (c) are used as the determination condition, the determination accuracy is improved.

  For example, the determination unit may further determine that the steering current exceeds the collision determination current threshold as a determination condition, and determine that the collision is an obstacle when all of the determination conditions are satisfied. In general, the steering actuator is subjected to feedback control, and when the determination conditions are combined, when there is an obstacle collision, the steering current is increased by feedback control. If the deviation between the target turning angle and the actual turning angle described above exceeds the collision determination deviation threshold and the turning current exceeds the collision determination current threshold, the determination unit determines that an obstacle has collided. .

  In addition, for example, the determination unit may determine whether the deviation between the target turning angle and the actual turning angle exceeds a collision determination deviation threshold, or whether the steering current exceeds a collision determination current threshold. In addition, | the turning angular velocity | <the collision determination turning angular velocity threshold and the | target turning angular acceleration | <the collision determination target steering angular acceleration threshold are used as the determination conditions, and all of these determination conditions are satisfied. It may be determined that an obstacle collides.

  During sudden steering or sine steering, the deviation between the target turning angle and the actual turning angle and the turning current may increase. Therefore, even though the turning wheels do not collide with obstacles. There is a possibility that an obstacle collision may be misjudged.

  Here, the steered angular velocity is output at the time of sudden steering or sin steering, but decreases at the time of an obstacle collision, and the steered angular velocity is constant while the steered wheel is hitting the obstacle. And takes a value near 0.

  Note that when turning the steering back during sin steering, the turning angular velocity becomes a value less than the collision determination turning angular velocity threshold value, and therefore there is a possibility of erroneous detection only with the turning angular velocity. For this reason, by setting the time when the target turning angular acceleration is less than the collision determination target turning angular acceleration threshold as the further determination condition of the obstacle collision, it is possible to prevent the erroneous determination in the turning back at the time of the sin steering.

  In this manner, the obstacle collision is caused by further adding that the turning angular velocity and the target turning angular acceleration are less than the collision determination turning angular velocity threshold and the collision determination target turning angular acceleration threshold, respectively, as a determination condition. It is possible to eliminate false positives.

  Further, for example, the determination unit may exceed a collision determination deviation threshold between the target turning angle and the actual turning angle, the steering current may exceed a collision determination current threshold, and | estimated axial force It may be determined as an obstacle collision when all of these determination conditions are satisfied, with the determination condition that ||| ideal axial force | exceeds the collision determination axial force difference threshold.

  In contrast to the ideal axial force calculated from the target steering angle, the estimated axial force calculated from the steering current as road surface information increases at the time of obstacle collision. For this reason, the absolute value of the estimated axial force is larger than the absolute value of the ideal axial force. In the case of | estimated axial force−ideal axial force |> threshold, on the low μ road, the ideal axial force> estimated axial force, and there is a possibility of an erroneous determination.

  In this way, it is possible to eliminate an erroneous determination of an obstacle collision by adding that the | estimated axial force |-| ideal axial force | exceeds the collision determination axial force difference threshold as a determination condition. Become.

  According to the present invention, in a steer-by-wire vehicle steering device that sets a reaction force by distributing an estimated axial force and an ideal axial force, when a steered wheel collides with an obstacle, the collision of the obstacle is given to the steering wheel. There is an effect that can be conveyed.

FIG. 1 is an overall schematic view showing a steering control device in which a steer-by-wire type vehicle steering device according to a first embodiment is controlled. The block diagram of the steering control apparatus of the embodiment. The figure which shows the threshold value of the steering angle and turning angle concerning the embodiment. The block diagram which shows the axial force distribution calculating part concerning the embodiment. Explanatory drawing of the determination conditions concerning the embodiment. Explanatory drawing of the determination conditions concerning the embodiment. The block diagram of the steering apparatus for vehicles of 2nd Embodiment. (A) And (b) is explanatory drawing of the determination conditions of 2nd Embodiment. The block diagram of the steering control device of a 3rd embodiment. Explanatory drawing of the determination conditions of 3rd Embodiment. FIG. 10 is an overall schematic diagram showing a steering control device steering control device that is a control target of a steer-by-wire vehicle steering device of a fourth embodiment.

First Embodiment
Hereinafter, a first embodiment of a steering control device in which a steer-by-wire type vehicle steering device is controlled will be described with reference to the drawings.

  As shown in FIG. 1, in the steering control device according to the present embodiment, the steering wheel (steering 10) is connected to a reaction force actuator 20 that applies a reaction force that is a force against the operation of the steering 10. . The reaction force actuator 20 drives a steering shaft 22 fixed to the steering wheel 10, a reaction force side speed reducer 24, a reaction force motor 26 having a rotating shaft 26 a connected to the reaction force side speed reducer 24, and the reaction force motor 26. An inverter 28 is provided. Here, the reaction force motor 26 is a surface magnet synchronous motor (SPMSM).

  The reaction force motor 26 is connected to the battery 72 via the inverter 28. The inverter 28 is a circuit that opens and closes between each of the positive electrode and the negative electrode of the battery 72 and each of the three terminals of the reaction force motor 26.

The steered actuator 40 includes a rack and pinion mechanism 52, a steered side motor 56 (SPMSM), and an inverter 58.
The rack-and-pinion mechanism 52 includes a rack shaft 46 and a pinion shaft 50 arranged with a predetermined crossing angle, and the rack teeth 46 b formed on the rack shaft 46 and the pinion teeth 50 a formed on the pinion shaft 50 Meshed. The steered wheels 30 are connected to both ends of the rack shaft 46 via tie rods (not shown). The rack shaft 46 corresponds to a steered shaft.

  The pinion shaft 50 is connected to the rotating shaft 56 a of the steered side motor 56 via the steered side speed reducer 54. An inverter 58 is connected to the steered side motor 56. The rack shaft 46 is accommodated in the rack housing 44.

  In FIG. 1, among the symbols of the switching elements (MOS field effect transistors) constituting the inverter 58, the ones connected to the three terminals of the steered side motor 56 are “u, v, w”. The upper arm is given “p” and the lower arm is given “n”. In the following, “u, v, w” will be collectively described as “¥” and “p, n” will be collectively described as “#”. That is, the inverter 58 switches between the switching element S ¥ p that opens and closes between the positive terminal of the battery 72 and the terminal of the steered side motor 56 and between the negative terminal of the battery 72 and the terminal of the steered side motor 56 A series connection body with the element S ¥ n is provided. A diode D ¥ # is connected in reverse parallel to the switching element S ¥ #.

  A spiral cable device 60 is connected to the steering 10. The spiral cable device 60 is accommodated in a space defined by the first housing 62 fixed to the steering 10, the second housing 64 fixed to the vehicle body, the first housing 62 and the second housing 64, and the second A tubular member 66 fixed to the housing 64 and a spiral cable 68 wound around the tubular member 66 are provided. The steering shaft 22 is inserted into the cylindrical member 66. The spiral cable 68 is an electrical wiring that connects the horn 70 fixed to the steering 10 and the battery 72 fixed to the vehicle body.

  The control device 80 (steering control device) performs control to steer the steered wheels 30 according to the operation of the steering 10 by operating the steering device provided with the reaction force actuator 20 and the steering actuator 40. In the present embodiment, a steer-by-wire system is realized by the reaction force actuator 20 and the steering actuator 40, and the control device 80 executes control to steer the steered wheels 30 in accordance with the operation of the steering 10. The control device 80 corresponds to a steering control unit and a reaction force control unit.

  At this time, the control device 80 takes in the rotation angle θs 0 of the rotation shaft 26 a of the reaction force motor 26 detected by the steering sensor 92 and the steering torque Trqs applied to the steering shaft 22 detected by the torque sensor 94. Further, the control device 80 takes in the rotation angle θt 0 of the rotation shaft 56 a of the turning side motor 56 detected by the turning side sensor 90, and the vehicle speed V detected by the vehicle speed sensor 96. The control device 80 acquires voltage drops of the shunt resistors 86 connected to the respective source sides of the switching elements S ¥ n in the inverter 58 as the currents iu, iv, iw, and refers to these. Further, the control device 80 takes in a drive mode DM indicating a setting state of a control pattern of a vehicle-mounted engine or the like. Depending on the drive mode DM, the responsiveness (direct feeling) to the traveling of the vehicle to the fuel efficiency and the user's request may differ. For example, the drive mode DM includes an ECO mode that optimizes the output of the engine and the like so as to improve fuel efficiency, and a normal that optimizes the output of the engine and the like so that the responsiveness to the user's request is enhanced compared to the ECO mode. A sports mode that optimizes the output of the engine or the like so as to increase the responsiveness to the user's request regardless of the mode and fuel consumption is included. This drive mode DM is switched by a switch 98 that can be operated by a user, that is, a steering wheel.

  Specifically, the control device 80 includes a CPU 82 (central processing unit) and a memory 84. When the CPU 82 executes a program stored in the memory 84, the reaction force actuator 20 and the steering actuator 40 are operated. .

(Operation of the embodiment)
FIG. 2 shows a part of processing executed by the control device 80. The process shown in FIG. 2 describes a part of the process realized by the CPU 82 executing the program stored in the memory 84 for each type of the realized process.

  The integration processing unit M2 converts the rotation angle θs0 detected by the steering side sensor 92 and the rotation angle θt0 detected by the steered side sensor 90 into numerical values in an angle region wider than 0 to 360 °, and thereby the rotation angle. Let θs and θt. For example, when the steering 10 is fully rotated to the right or left from the neutral position for advancing the vehicle straight, the rotation shaft 26a rotates a plurality of times. Therefore, in the integration processing unit M2, for example, when the rotation shaft 26a rotates twice in the predetermined direction from the state where the steering 10 is at the neutral position, the output value is set to 720 °. The integration processing unit M2 sets the output value at the neutral position to zero.

  The weighing unit setting processing unit M4 calculates the steering angle θh by multiplying the output value of the steering sensor 92 processed by the integration processing unit M2 by the conversion coefficient Ks, and the processing by the integration processing unit M2 is performed. The turning value θp as the actual turning angle is calculated by multiplying the output value of the turning side sensor 90 by the conversion coefficient Kt. Here, the conversion factor Ks is determined in accordance with the rotational speed ratio between the reaction reduction gear 24 and the rotation shaft 26a of the reaction motor 26, and thereby, the change amount of the rotation angle θs of the rotation shaft 26a It is converted into the amount of rotation of the steering 10. Therefore, the steering angle θh is the rotation angle of the steering 10 based on the neutral position. The conversion coefficient Kt is a rotation speed ratio between the steered side reduction gear 54 and the rotating shaft 56 a of the steered side motor 56. Thereby, the rotation amount of the rotating shaft 56a is converted into the rotation amount of the steering wheel 10 when it is assumed that the steering shaft 22 is connected.

  The processing in FIG. 2 is positive when the rotation angles θs and θt, the steering angle θh, and the turning angle θp are rotation angles in a predetermined direction, and is negative when the rotation angles are in the opposite direction. For example, the integration processing unit M2 sets the output value to a negative value when the rotation shaft 26a rotates in the reverse direction to the predetermined direction from the state where the steering 10 is at the neutral position. However, this is only an example of the logic of the control system. In particular, in the present specification, when the rotation angles θs and θt, the steering angle θh, and the turning angle θp are large, it is assumed that the amount of change from the neutral position is large. In other words, the absolute value of the parameter that can take a positive or negative value as described above is large.

  The reaction torque setting processing unit M6 sets the reaction torque Trqa * based on the steering torque Trqs. The reaction torque Trqa * is set to a larger value as the steering torque Trqs is larger. The addition processing unit M8 adds the steering torque Trqs to the reaction torque Trqa * and outputs it.

  The reaction force setting processing unit M <b> 10 sets a reaction force Fir that is a force that resists the rotation of the steering wheel 10. Specifically, in the normal traveling state where the steered wheels 30 do not collide with the obstacle or in the stopped state, the reaction force setting processing unit M10 controls the base reaction force according to the operation of the steering 10 by the base reaction force setting processing unit M10a. Set Fd. Further, the reaction force setting processing unit M10 resists the steering 10 from being further moved to the upper limit side when the rotation amount of the steering 10 approaches the allowable maximum value by the restriction reaction force setting processing unit M10 b. Set the limiting reaction force Fie that is a force. Then, the reaction force setting processing unit M10 adds the base reaction force Fd and the restriction reaction force Fie by the addition processing unit M10c, and outputs this as a reaction force Fir.

The deviation calculation processing unit M12 outputs a value obtained by subtracting the reaction force Fir from the output of the addition processing unit M8.
The target steering angle calculation processing unit M20 sets the target steering angle θh * based on the output value of the deviation calculation processing unit M12. Here, a model equation expressed by the following equation (c1) which relates the output value Δ of the deviation calculation processing unit M12 and the target steering angle θh * is used.

Δ = C · θh * ′ + J · θh * ′ ′ (c1)
The model represented by the above equation (c1) is a relationship between the torque of the rotation shaft that rotates with the rotation of the steering 10 and the rotation angle in the case where the steering 10 and the steered wheels 30 are mechanically connected. It is a model that determines. In the above equation (c1), the viscosity coefficient C models the friction of the steering device, and the inertia coefficient J models the inertia of the steering device. Here, the viscosity coefficient C and the inertia coefficient J are variably set according to the vehicle speed V.

  The steering angle feedback processing unit M22 sets a target reaction force torque Trqr * that is a target value of the reaction force torque generated by the reaction force motor 26 as an operation amount for feedback control of the steering angle θh to the target steering angle θh *. To do. Specifically, the sum of the output values of a proportional element, an integral element, and a differential element, which has a value obtained by subtracting the steering angle θh from the target steering angle θh *, is set as a target reaction force torque Trqr *.

  The operation signal generation processing unit M24 generates an operation signal MSs for the inverter 28 based on the target reaction force torque Trqr * and outputs the operation signal MSs to the inverter 28. This is known, for example, to set the command value of the q-axis current based on the target reaction force torque Trqr * and to set the voltage command value of the dq axis as an operation amount for feedback controlling the current of the dq axis to the command value. It can be realized by current feedback control. The d-axis current may be controlled to zero, but when the rotational speed of the reaction force motor 26 is large, the field-weakening control may be performed by setting the absolute value of the d-axis current to a value larger than zero. . However, it is also possible to set the absolute value of the d-axis current to a value larger than zero in the low rotational speed region. The reaction torque setting processing unit M6, addition processing unit M8, reaction force setting processing unit M10, deviation calculation processing unit M12, target steering angle calculation processing unit M20, steering angle feedback processing unit M22, and operation signal generation processing unit M24. Is an example of a reaction force processing unit, and in particular, the steering angle feedback processing unit M22 and the operation signal generation processing unit M24 are an example of a steering angle control processing unit.

  The steering angle ratio variable processing unit M26 sets a target operating angle θa * for variably setting a steering angle ratio, which is a ratio between the steering angle θh and the turning angle θp, based on the target steering angle θh *. The addition processing unit M28 calculates the target turning angle θp * by adding the target operating angle θa * to the target steering angle θh *.

  The turning angle feedback processing unit M32 sets a target turning torque Trqt * generated by the turning side motor 56 as an operation amount for feedback control of the turning angle θp to the target turning angle θp *. Specifically, the sum of the output values of a proportional element, an integral element, and a differential element using a value obtained by subtracting the turning angle θp from the target turning angle θp * is taken as a target turning torque Trqt *.

  The operation signal generation processing unit M34 generates an operation signal MSt for the inverter 58 based on the target turning torque Trqt * and outputs the operation signal MSt to the inverter 58. This can be performed in the same manner as the operation signal generation processing by the operation signal generation processing unit M24. The turning angle feedback processing unit M32 and the operation signal generation processing unit M34 are an example of a turning angle control processing unit.

Maximum value selection processing unit M36 selects and outputs the larger value (maximum value θe) of target steering angle θh * and target turning angle θp *.
The base reaction force setting processing unit M10a receives the target turning angle θp * as an input. On the other hand, the limiting reaction force setting processing unit M10b sets the limiting reaction force Fie with the maximum value θe as an input. This is both immediately before the end of the rack shaft 46 comes into contact with the rack housing 44 (rack stopper) as the rack shaft 46 is displaced in the axial direction, and just before the steering 10 rotates to the upper limit value determined from the spiral cable 68. In FIG. 4, the steering force is set to increase the force that resists the steering 10 from further increasing the magnitude of the steering angle. This will be described below.

  FIG. 3 shows the relationship between upper limit values θhH and θpH of the steering angle θh and the turning angle θp. As illustrated, in the present embodiment, the upper limit value θhH of the steering angle θh and the upper limit value θpH of the turning angle θp are substantially equal. This is realized by setting the measurement unit of the steering angle θh and the turning angle θp by the measurement unit setting processing unit M4. In the present embodiment, when the steering shaft 22 is in a connected state, when the rack shaft 46 is displaced in the axial direction until it comes into contact with the rack housing 44, the spiral is set so that the steering 10 can be further rotated slightly. The length of the cable 68 has a slight margin. For this reason, steering is performed by setting the steering angle θh as the rotation angle of the steering 10 and the turning angle θp as the rotation angle of the steering 10 assuming that the target operating angle θa * is zero by the weighing unit setting processing unit M4. The upper limit value θhH of the angle θh and the upper limit value θpH of the turning angle θp have substantially the same value.

  In the present embodiment, the steering angle θh and the turning angle θp are provided with the common threshold θen, and the steering angle θh reaches the upper limit value θhH and before the turning angle θp reaches the upper limit value θpH. Increase control of reaction force. The limiting reaction force setting processing unit M10b illustrated in FIG. 2 includes a map that defines the relationship between the maximum value θe and the limiting reaction force Fie. In this map, when the magnitude of the maximum value θe becomes equal to or greater than the common threshold θen, the limiting reaction force Fie becomes larger than zero, and in particular, the limiting reaction force Fie exceeds the common threshold θen to a certain extent. In other words, the value is set so large that it cannot be operated by human power any more. Although FIG. 2 only shows that the limiting reaction force Fie increases as the maximum value θe increases from zero to a predetermined rotation direction, it is a case where the restriction reaction force Fie increases in a direction opposite to the predetermined rotation direction. Even so, the absolute value of the limiting reaction force Fie increases. However, the limiting reaction force Fie in the process of FIG. 2 is negative in the direction opposite to the predetermined rotation direction.

  Determination unit M40 determines whether or not turning wheel 30 has collided with an obstacle such as a curb or the like. Although it is not limited to the curb that the steered wheels 30 collide and the turning of the steered wheels 30 becomes difficult, the following description will be made on the case of collision with the curb as a representative example of the obstacle.

  Specifically, determination unit M40 inputs target turning angle θp * and turning angle θp (actual turning angle), and | target turning angle θp * −turning angle θp (actual turning angle) | = A turning angle deviation Δθp is calculated, and it is determined whether the turning angle deviation Δθp exceeds the collision determination deviation threshold value Δθpr.

  That is, when the steered wheels 30 collide with a curb (obstacle), the steered wheels 30 can not be steered by the curbs, and the steered angle θp (actual steered angle) becomes constant. Since there is no mechanical connection between the steered wheels 30 and the steering 10, the steer 10 is steered so that the steer-by-wires have the same direction as the steered wheels 30 after the steered wheels 30 collide with a curb (obstacle). This is because the target turning angle θp * increases and is calculated in accordance with the steering (see FIG. 5).

  Accordingly, when the turning angle deviation Δθp between the target turning angle θp * and the turning angle θp (actual turning angle) exceeds the collision determination deviation threshold value Δθpr, the determination unit M40 is one of the determination conditions for the curb collision. Is determined to be satisfied.

Further, the determination unit M40 inputs the values of the currents iu, iv, iw which are the turning currents, and calculates the q-axis current iq based on these. The calculation of the q-axis current iq will be described later.
The determination unit M40 determines whether the steering current exceeds the collision determination current threshold ir using the q-axis current iq as the steering current.

  As shown in FIG. 6, when there is a curb collision, the steering current is increased by the feedback control. When the increasing turning current exceeds the collision determination current threshold ir, that is, when one or more turning currents exceed the collision determination current threshold ir, one of the judgment conditions of the curb collision is set. It is determined that the user is satisfied.

  If both of the above two determination conditions are satisfied, the determination unit M40 determines that there is a curb collision, and determines that the collision flag F of “1” is an axial force distribution calculation unit M10aa of the reaction force setting processing unit M10 described later. Output to. Further, when at least one of the above two determination conditions is not satisfied, the determination unit M40 determines that there is no curb collision, and a collision flag F of "0" is a reaction force setting processing unit described later. It outputs to the axial force distribution calculating part M10aa of M10.

<When collision flag F = 0>
As shown in FIG. 2, in the present embodiment, the reaction force setting processing unit M10 determines the ideal axial force Fib and the estimated axial force Fer so as to reflect the axial force applied to the steered wheels 30 from the road surface. As a distribution component distributed at a ratio, an axial force distribution calculation unit M10aa is provided which executes calculation for setting a base reaction force Fd. The axial force applied to the steered wheels 30 is road surface information transmitted from the road surface to the steered wheels 30.

  Further, the reaction force setting processing unit M10 is an ideal value of the axial force (transmission force transmitted to the turning wheel 30) acting on the turning wheel 30, among the components of the base reaction force Fd, and the road surface information is not reflected An ideal axial force calculation unit M10ab is provided that calculates an ideal axial force Fib that is an ideal component. The ideal axial force calculation unit M10ab calculates an ideal axial force Fib based on the target turning angle θp *. For example, the absolute value of the ideal axial force Fib is set to increase as the absolute value of the target turning angle θp * increases. The axial force distribution calculation unit M10aa is an example of a distribution component calculation unit. The ideal axial force calculation unit M10ab is an example of an ideal component calculation unit.

  The reaction force setting processing unit M10 is an estimated value of the axial force acting on the steered wheels 30 (the transmission force transmitted to the steered wheels 30) among the components of the base reaction force Fd, and road surface information is reflected. An estimated axial force calculation unit M10ac is provided to calculate an estimated axial force Fer, which is a road surface component. The estimated axial force calculation unit M10ac acquires the currents iu, iv, iw that are actual current values of the steered side motor 56, and calculates the estimated axial force Fer based on the q-axis current iq calculated by this. The calculation of the current ip of the q axis can be realized based on the rotation angle θt0 of the turning side motor 56 by conversion processing of the dq axis which is a rotation coordinate system to the coordinate system. Then, the estimated axial force calculation unit M10ac calculates the estimated axial force Fer by multiplying the q-axis current iq by a predetermined coefficient K1.

  Here, the predetermined coefficient K1 is set based on the gear ratio of the turning side reduction gear 54, the ratio of the torque of the pinion shaft 50 to the axial force of the rack shaft 46, and the torque constant. That is, the torque of the turning side motor 56 is determined by multiplying the q-axis current iq by a constant. Then, the torque of the turning side motor 56 is converted by the turning side reduction gear 54 or the like and added to the rack shaft 46. Therefore, the axial force applied to the rack shaft 46 by the steered side motor 56 can be calculated by multiplying the q-axis current iq by a predetermined coefficient K1. When the axial force applied to the rack shaft 46 by the steered side motor 56 and the axial force applied from the road surface to the steered wheels 30 can be regarded as a balanced relationship, the steered wheel 30 is turned based on the q-axis current iq. Thus, the axial force applied from the road surface can be estimated as the estimated axial force Fer. The estimated axial force Fer is a component that reflects at least road surface information. The estimated axial force calculation unit M10ac is an example of a road surface component calculation unit.

  As shown in FIG. 4, the axial force distribution calculation unit M10aa calculates a distribution gain Gib and a distribution gain Ger that are distribution ratios for distributing the ideal axial force Fib and the estimated axial force Fer, respectively. It has. The gain calculation unit M10aaa includes a three-dimensional map that defines the relationship between the vehicle speed V, each of the distribution gains Gib and Ger, and the drive mode DM selected by the user, and receives the drive mode DM and the vehicle speed V as inputs. Each distribution gain Gib, Ger is map-calculated. While the distribution gain Gib is smaller in value when the vehicle speed V is large, the distribution gain Ger is larger in value when the vehicle speed V is large than when it is small.

  The values of the distribution gains Gib and Ger are set such that the sum becomes 1 when, for example, the drive mode DM is the ECO mode or the normal mode. On the other hand, each of the distribution gains Gib and Ger increases the value of the distribution gain Ger so that the sum exceeds 1, for example, when the drive mode DM is the sports mode. In particular, the distribution gain Ger increases as the vehicle speed V increases. It is set to increase the value.

  Then, the axial force distribution calculation unit M10aa multiplies the output value of the ideal axial force calculation unit M10ab by the distribution gain Gib by the multiplication processing unit M10aab. Further, the axial force distribution calculation unit M10aa multiplies the output value of the estimated axial force calculation unit M10ac by the distribution gain Ger by the multiplication processing unit M10aac. Further, in the addition processing unit M10aad, the axial force distribution calculation unit M10aa adds the product obtained by multiplying the distribution gain Gib by the ideal axial force Fib and the product obtained by multiplying the distribution gain Ger by the estimated axial force Fer, Calculate and output force Fd.

  As described above, when the collision flag F = 0, in the vehicle traveling state, the ideal axial force is main when the steering is near the neutral center, and the estimated axial force when the steering is cut. Is distributed to become the main. Further, in the stopped state, the reaction force based on the ideal axial force is transmitted to the steerer in the entire area of the operation range of the rack shaft 46 (the steered shaft).

<When collision flag F = 1>
When the collision flag F = 1, the axial force distribution operation unit M10aa of the reaction force setting processing unit M10 sets the distribution gain Gib of the ideal axial force to 0 and sets the distribution gain Ger of the estimated axial force to 1. As a result, the axial force distribution calculation unit M10aa substitutes the ideal axial force calculated from the target turning angle as the axial force transmitted to the rack shaft 46 (steering shaft) to the estimated axial force calculated from the turning current By switching, the base reaction force Fd is calculated. The reaction force setting processing unit M10 adds the base reaction force Fd and the limiting reaction force Fie by the addition processing unit M10c, and outputs this as the reaction force Fir to the deviation calculation processing unit M12.

According to the present embodiment described above, the following actions and effects can be obtained.
In the steering control device in which the steer-by-wire type vehicle steering apparatus of the present embodiment is controlled, the turning angle deviation Δθp between the target turning angle θp * and the turning angle θp (actual turning angle) is a collision determination deviation It is determined that the threshold value Δθpr has been exceeded and that the q-axis current iq (turning current) exceeds the collision determination current threshold ir. The control device 80 (a reaction force control unit) includes a determination unit M40 that determines that the steered wheels 30 collide with a curb when the determination conditions are satisfied. After the determination unit M40 determines that a curb collision has occurred, the ideal axial force Fib calculated from the target turning angle is switched to the estimated axial force Fer as the axial force transmitted to the rack shaft 46 (turning shaft), and the reaction force is determined. Calculate.

  As a result, according to the present embodiment, in the steering control device for controlling the steer-by-wire type vehicle steering device that sets the reaction force by the distribution of the estimated axial force and the ideal axial force, it is turned to a curb (obstacle) When the steering wheel collides, there is an effect that the collision of a curb (obstacle) can be transmitted to the steerer by the reaction force based on the estimated axial force.

  In addition, by giving the reaction force of the curb collision calculated based on the estimated axial force to the steerer, it is possible to further prevent the steering from being cut to the curb side, thereby suppressing mechanical damage. There is an effect that can.

Second Embodiment
Next, a steering control device in which the steer-by-wire type vehicle steering device of the second embodiment is controlled will be described with reference to FIGS. 7 and 8. In addition, about the same structure as 1st Embodiment, or the structure equivalent, the same code | symbol is attached | subjected, the detailed description is abbreviate | omitted, and a different structure is demonstrated.

  In the present embodiment, a determination unit M42 is provided instead of the determination unit M40 of the first embodiment. In the determination unit M42, the following two determination conditions are further satisfied as well as the determination whether the two determination conditions performed by the determination unit M40 are satisfied as the determination conditions for determining the presence or absence of a curb collision It is different from the determination unit M40 in that it is determined whether or not it is.

The added determination condition is | steering angular velocity | <collision judgment steering angular velocity threshold A and | target steering angular acceleration | <collision judgment target steering angular acceleration threshold B.
Determination unit M 42 differentiates the input turning angle θp (actual turning angle) to obtain turning angular velocity θp / dt, and it is determined whether | turning angular velocity | <collision determination turning angular velocity threshold A or not Determine whether.

  During sudden steering or sin steering by the steering 10, the turning angle deviation Δθp between the target turning angle θp * and the turning angle θp (actual turning angle) and the q-axis current iq (steering current) increase. There are things to do.

  For this reason, in the said embodiment, although the steered wheel 30 is not curb collision, there exists a possibility of misjudging with curb collision. On the other hand, the turning angular velocity θp / dt is output at the time of sudden steering or sin steering, but decreases after the curb collision, as shown in FIG. While hitting, the turning angular velocity is constant and takes a value near zero.

For this reason, in the present embodiment, it is determined whether or not | turning angular velocity θp / dt | <collision determination turning angular velocity threshold A.
Since the turning angular velocity θp / dt becomes a value smaller than the collision determination turning angular velocity threshold A when turning back the steering at the time of sin steering, it is possible to make an erroneous determination by comparing and judging only the turning angular velocity θp / dt. There is sex.

  For this reason, as shown in FIG.8 (b), when the target turning angular acceleration d ^ 2 (theta) p * / dt ^ 2 is less than the collision determination target turning angular acceleration threshold B, it is set as the further determination conditions of a curb collision. In this case, erroneous determination is not made at the turning-back at the time of sin steering. Note that “^” indicates power, and “^ 2” indicates square.

  In this way, the determination unit M42 determines that a curb collision has occurred when all of the above four determination conditions are satisfied, and sets the collision flag F of “1” to the axial force distribution calculation of the reaction force setting processing unit M10. Output to section M10aa. When at least one of the above four determination conditions is not satisfied, the determination unit M42 determines that there is no curb collision, and sets the collision flag F of "0" to the axial force of the reaction force setting processing unit M10. Output to the distribution operation unit M10aa. Other configurations are the same as those of the first embodiment.

  As described above, in the present embodiment, in addition to the determination conditions in the first embodiment, | turning angular velocity | <collision determination turning angular velocity threshold A, and | target turning angle acceleration | <collision determination By using the target rudder angular acceleration threshold B as a determination condition, it is possible to eliminate erroneous determination of curb collision.

Third Embodiment
Next, a steering control device in which the steer-by-wire type vehicle steering device of the third embodiment is controlled will be described with reference to FIGS. 9 and 10. In addition, about the same structure as 1st Embodiment, or the structure equivalent, the same code | symbol is attached | subjected, the detailed description is abbreviate | omitted, and a different structure is demonstrated.

  In the present embodiment, a determination unit M44 is provided instead of the determination unit M40 of the first embodiment. In the determination unit M44, as the determination condition for determining the presence or absence of a curb collision, in addition to the determination as to whether or not the two determination conditions performed by the determination unit M40 are satisfied, | estimated axial force |-| ideal It is added as a judgment condition that the axial force | exceeds the collision judgment axial force difference threshold D.

The determination unit M44 receives the estimated axial force Fer and the ideal axial force Fib, and determines whether | estimated axial force Fer |-| ideal axial force Fib | satisfies the collision determination axial force difference threshold D or not.
As shown in FIG. 10, the estimated axial force calculated from the road surface information increases at the time of curb collision with respect to the ideal axial force calculated from the target turning angle that is angle information, so the absolute value of the estimated axial force is There is a characteristic that becomes larger than the absolute value of the ideal axial force. Note that a determination condition of | estimated axial force−ideal axial force |> threshold is also conceivable, but in a low μ road, ideal axial force> estimated axial force may be satisfied.

  As described in the second embodiment, the steering angle deviation Δθp between the target turning angle θp * and the turning angle θp (actual turning angle) at the time of sudden steering by the steering 10 or at the time of sin steering, The q-axis current iq (steering current) may increase. For this reason, in 1st Embodiment, although the steered wheel 30 is not curb collision, there exists a possibility of misjudging with curb collision.

  On the other hand, the determination unit M44 determines that there is a curb collision when there is no erroneous determination at the time of sudden steering by the steering 10 or at the time of sin steering, and any of the three determination conditions described above is satisfied. The collision flag F is output to the axial force distribution calculation unit M10aa of the reaction force setting processing unit M10. When at least one of the above four determination conditions is not satisfied, the determination unit M42 determines that there is no curb collision, and sets the collision flag F of "0" to the axial force of the reaction force setting processing unit M10. Output to the distribution operation unit M10aa. The other configuration is the same as that of the first embodiment.

  As described above, in addition to the determination condition in the first embodiment, the condition that | the estimated axial force |-| ideal axial force | exceeds the collision determination axial force difference threshold D is further set as the determination condition. This makes it possible to eliminate erroneous determination of curb collision.

In addition, each embodiment can also be implemented with the following forms.
In the above embodiment, the steering control device is controlled to be a clutchless steer-by-wire steering device, but as shown in FIG. 11, a steer-by-wire steering device with a clutch is controlled. You may actualize to the steering control apparatus made into object.

  The steering shaft 22 is connectable to the pinion shaft 42 of the steering actuator 40 via the clutch 12. With the above configuration, the turning actuator 40 includes the rack and pinion mechanisms 48 and 52, the turning side motor 56, and the inverter 58. Further, the rack and pinion mechanism 48 includes a rack shaft 46 and a pinion shaft 42 disposed with a predetermined crossing angle, and includes rack teeth 46 a formed on the rack shaft 46 and pinion teeth 42 a formed on the pinion shaft 42. Are engaged.

  The clutch 12 is in a released state or a connected state according to a command from the control device 80. Normally, the clutch 12 is in the released state, but when there is an abnormality such as a steering reaction force, control is performed by the command so as to be in the connected state.

-A judgment part is good also as a judgment condition only when the collision judgment deviation threshold value of a target turning angle and an actual turning angle is exceeded.
· The determination unit (a) that the turning current exceeds the collision determination current threshold, (b) | turning angle velocity | <collision determination turning angular velocity threshold, and | target turning angle acceleration | The determination condition may be all of the determination target rudder angular acceleration threshold and (c) | estimated axial force |-| ideal axial force | exceeds the collision determination axial force difference threshold. When all the determination conditions are satisfied, the determination unit may output a collision flag F of “1” to M10aa.

  The values of the distribution gains Gib and Ger may be set so that the sum is 1 regardless of the drive mode DM. In this case, the gain calculation unit M10aaa may calculate the remaining distribution gains by performing map operation on any of the distribution gains Gib and Ger and subtracting the obtained distribution gains from one. The distribution gains Gib and Ger may be set so that the sum is less than 1.

  · Parameters for calculating the distribution gains Gib and Ger include steering angle θh, turning angle θp, rotational angular velocity (so-called yaw rate) about the vertical axis passing through the center of gravity of the vehicle, and turning wheels 30 on the left and right Alternatively, parameters such as a wheel speed difference of a wheel speed sensor provided respectively may be used instead of the drive mode DM or the vehicle speed V. The parameters including the drive mode DM and the vehicle speed V may be used alone or in any combination. Further, each allocation gain Gib, Ger may be calculated based on information obtained from GPS or the like. In this manner, the steering feeling can be adjusted by arbitrarily selecting a parameter to be emphasized, and the degree of freedom in adjusting the steering feeling can be enhanced.

  The relationship between the distribution gain Gib and Ger and the vehicle speed V can be changed. For example, the distribution gain Gib may be smaller as the vehicle speed V is larger. Also, the distribution gain Ger may be a value that increases as the vehicle speed V increases. That is, the relationship with the vehicle speed V can be set for each of the distribution gains Gib and Ger according to the vehicle specifications, the vehicle usage environment, and the like.

  -The type of drive mode DM may be increased or decreased according to vehicle specifications. In this case, a map may be provided according to the type of drive mode DM. The drive mode DM may not be selected by the user. For example, the drive mode DM may be automatically selected by the control device 80 (vehicle side) according to the traveling state of the vehicle or the user's operation. Good.

In the first embodiment, the limiting reaction force setting processing unit M10b may be deleted from the reaction force setting processing unit M10.
In each embodiment, the reaction force motor 26 and the steered side motor 56 are not limited to SPMSM, and for example, an IPMSM may be used.

  -In each embodiment, if it is a rack assist type as the steering actuator 40, for example, what arranges the steering side motor 56 coaxially with the rack shaft 46, a steering side motor parallel to the rack shaft 46, etc. 56 may be arranged.

  In each embodiment, the control device 80 may be provided with dedicated hardware (ASIC) in addition to the CPU 82 and the memory 84. Then, a part of the processing of the CPU 82 may be hardware processing, and the CPU 82 may acquire it from the hardware.

10 ... Steering, 12 ... Clutch, 20 ... Reaction force actuator,
22 ... steering shaft, 24 ... reaction force reduction gear, 26 ... reaction force motor
26a ... rotating shaft, 28 ... inverter, 30 ... steered wheel,
40: steering actuator, 42: pinion shaft, 44: rack housing,
46 ... rack shaft (steering shaft), 46b ... rack teeth, 50 ... pinion shaft,
50a ... pinion teeth, 52 ... rack and pinion mechanism,
54: turning side reduction gear, 56: turning side motor, 56a: rotating shaft,
58 ... Inverter, 60 ... Spiral cable device,
62 ... 1st housing, 64 ... 2nd housing, 66 ... Cylindrical member,
68 ... spiral cable, 70 ... horn, 72 ... battery,
80 ... Control device (steering control unit, reaction force control unit), 82 ... CPU,
84 ... Memory, 86 ... Shunt resistance, 90 ... Steering side sensor,
92 ... steering side sensor, 94 ... torque sensor,
96 ... vehicle speed sensor, 98 ... switch,
M10: Reaction force setting processing unit, M10a: Base reaction force setting processing unit,
M10aa: axial force distribution operation unit, M10aaa: gain operation unit,
M10aab ... multiplication processing unit, M10aac ... multiplication processing unit,
M10aad ... addition processing unit, M10ab ... ideal axial force calculation unit,
M10ac: Estimated axial force calculation unit, M10b: Reaction force setting processing unit for restriction,
M10c ... addition processing unit, M12 ... deviation calculation processing unit,
M20 ... Target steering angle calculation processing unit, M22 ... Steering angle feedback processing unit,
M24: operation signal generation processing unit, M26: steering angle ratio variable processing unit,
M28 ... addition processing unit, M32 ... turning angle feedback processing unit,
M34 ... operation signal generation processing unit, M36 ... maximum value selection processing unit,
M40, M42, M44 ... determination unit, M48 ... target steering angle calculation processing unit.

Claims (5)

A reactive actuator that applies a reaction force that opposes the operation of steering, a steering actuator that steers the steered wheels through a steered shaft under a power cutoff state between the steered wheels and the steering, the turning A steer-by-wire type vehicle steering apparatus comprising: a steering control unit that controls a rudder actuator in accordance with the steering of the steering; and a reaction control unit that calculates the reaction force for controlling the reaction force actuator. A steering control device to be controlled,
The reaction force control unit includes a determination unit that determines an obstacle collision when at least a collision determination deviation threshold between a target turning angle and an actual turning angle is exceeded as a determination condition. For steer-by-wire vehicles that calculate the reaction force by switching the ideal axial force calculated from the target turning angle as the axial force transmitted to the shaft to the estimated axial force calculated from the turning current of the turning actuator A steering control device that controls the steering device. The determination unit further determines an obstacle collision when any combination of the following (a) to (c) is satisfied as a determination condition and all the combination determination conditions are satisfied. The steering control apparatus which made the control object the vehicle steering apparatus of the steer-by-wire type as described in 4.
(A) The turning current exceeds the collision determination current threshold.
(B) | turning angular velocity | <collision determination turning angular velocity threshold, and | target turning angular acceleration | <collision determination target steering angle acceleration threshold.
(C) | estimated axial force | --ideal axial force | exceeds the collision determination axial force difference threshold.   The determination unit further determines that the steering current exceeds the collision determination current threshold as the determination condition, and determines that the collision is an obstacle when all the determination conditions are satisfied. A steering control device for which a steer-by-wire vehicle steering device is controlled.   The determination unit further determines that | turning angular velocity | <collision determination turning angular velocity threshold and | target turning angle acceleration | <collision determination target steering angle acceleration threshold, as the determination condition, 4. The steering control apparatus according to claim 3, wherein it is determined that an obstacle collision occurs when all the determination conditions are satisfied.   The determination unit further determines that | estimated axial force | − | ideal axial force | exceeds the collision determination axial force difference threshold as the determination condition, and when all the determination conditions are satisfied, an obstacle collision occurs. A steering control apparatus for controlling the steer-by-wire type vehicle steering apparatus according to claim 3, which is determined as