JP4466066B2 - Vehicle steering control device - Google Patents

Description

  The present invention belongs to the technical field of a vehicle steering control device employed in a steering system such as a steer-by-wire system in which there is no mechanical connection between a steering side having steering means and a steered side having steered wheels.

In a steering reaction force generation mechanism of a so-called steer-by-wire system in which a steering wheel and a steered wheel (= steering wheel) are not mechanically connected, conventionally, the steering reaction force applied by a motor is the steering wheel angle (= (Steering angle) and steering angular velocity are multiplied by a gain determined in advance according to the vehicle speed, and added to each other to give feedback from the road surface. It has been obtained by a method of adding the product of the deviation between the target value of the ratio) and the actual value multiplied by a gain corresponding to the vehicle speed (see, for example, Patent Document 1).
JP 2003-137127 A

  However, in the conventional vehicle steering control device, the more stable the angle control on the steered side with respect to the disturbance from the road surface or the like, that is, the fluctuation with respect to the command value when the disturbance is applied. The smaller the is, the smaller the deviation between the target value and the actual value of the steering gear ratio. For this reason, the reaction force command value obtained from this term also becomes small, and there is a problem that a sufficient effect may not be obtained when information from the road surface is fed back.

  The present invention has been made paying attention to the above problem, and even if the steering side control has a strong stability against disturbance and there is almost no difference between the target turning angle and the actual turning angle, the steering reaction can be reduced. It is an object of the present invention to provide a vehicle steering control device that can accurately simulate a steering reaction force with respect to a disturbance equivalent in calculating a force command value.

In order to achieve the above object, in the present invention,
A steering system having a steering reaction force actuator for generating a reaction force in a steering means and a steering motor for changing a turning angle of a steered wheel ,
The steering system includes: a steering reaction force control unit that calculates a steering reaction force command value for the steering reaction force actuator; and a steering motor that turns a turning angle of a steered wheel to a target turning angle. A turning angle control means for calculating a command current ,
The turning angle control means has a disturbance compensator that calculates a disturbance estimated value based on the command current and the actual motor angle of the steering motor, and compensates the command current,
The steering reaction force control means, the disturbance estimated value and the disturbance equivalent, characterized in that the feedback only disturbance equivalent estimated to the steering reaction force command value.

Therefore, in the vehicle steering control device according to the present invention, the steering reaction force control means for calculating the steering reaction force command value for the steering reaction force actuator, and the turning angle of the steered wheels is the target turning angle. Steering angle control means for calculating a command current to the steering motor, and the steering angle control means is based on the command current and the actual motor angle of the steering motor. A disturbance compensator that calculates an estimated value and compensates for the command current, and the steering reaction force control means uses the disturbance estimated value estimated using the disturbance compensator as a disturbance equivalent, and only the estimated disturbance equivalent Is fed back to the steering reaction force command value, so that the steering reaction force command value is stable even if the turning side control has strong stability against disturbance and there is almost no difference between the target turning angle and the actual turning angle. Accurately calculate the steering reaction force against the disturbance equivalent Rukoto can.

  Hereinafter, the best mode for carrying out the vehicle steering control apparatus of the present invention will be described based on Examples 1 to 3 shown in the drawings.

First, the configuration will be described.
FIG. 1 is an overall view showing a steer-by-wire system to which the vehicle steering control device of the first embodiment is applied. FIG. 2 is an overall view of a steering reaction force control system and a turning angle control system of the vehicle steering control device of the first embodiment. It is a figure which shows a structure.

  As shown in FIG. 1, the steer-by-wire system to which the first embodiment device is applied includes a steering reaction device 3 having a steering wheel 1 (steering means) and a steering reaction force actuator 2, steered wheels 4, 5 and rolling wheels. There is no mechanical connection between the steering device 7 and the steering actuator 6.

  The steering reaction device 3 includes a steering wheel 1, a steering column shaft 8, and a steering reaction force actuator 2 provided to the steering column shaft 8 via a reduction gear mechanism.

  The steering reaction force actuator 2 is a motor with a clutch, and is provided with a steering reaction force motor angle sensor 9 as a steering reaction force motor angle detection means for detecting the rotation speed of the motor shaft. This steering reaction force motor angle sensor 9 is used as a steering angle detection means for detecting a steering angle.

  As an electronic control means for controlling the steering reaction force actuator 2, a steering reaction force device controller 10 (steering reaction force control means) is provided, and the steering reaction force device controller 10 includes a steering reaction force motor angle. Input information is supplied from a sensor 9, a vehicle speed sensor 11 as vehicle speed detection means, a yaw rate sensor 12 as yaw rate detection means, and a lateral acceleration sensor 13 as lateral acceleration detection means.

  The steering reaction force controller 10 includes a road surface μ estimating means (road surface friction coefficient estimating means) for estimating a road surface μ from a vehicle speed V, a yaw rate Y, a lateral acceleration G, and the like, a steering input equivalent torque Ts and a steering output. Motor control command value calculating means for calculating a motor control command value Tms by applying a limiter process to the motor control command value Tm obtained by adding the equivalent torque Tf and the disturbance equivalent torque To, Motor driving means by a motor driving circuit for converting into a command current of the force actuator 2.

  The steering device 7 includes a steering actuator 6, a steering gear mechanism 14 driven by the steering actuator 6, and motion conversion mechanisms 15 and 16 provided at both ends of the steering gear mechanism 14. And steered wheels 4 and 5 connected to each other.

  The steering actuator 6 is a motor with a clutch, like the steering reaction force actuator 2, and a steering motor angle sensor 17 as a steering motor angle detection means for detecting the rotational speed of the motor shaft is provided. It is attached. The steered motor angle sensor 17 is used as a steered angle detecting means for detecting the steered angle.

  As electronic control means for controlling the steering actuator 6, a steering device controller 18 (steering angle control means) is provided, and the steering device controller 18 and the steering reaction force device controller 10 are: They are connected by a bidirectional communication line 19 that exchanges information with each other. Input information from the steering motor angle sensor 17 is supplied to the steering device controller 18.

  The steering device controller 18 includes disturbance estimation means using a robust compensator, motor control command value calculation means for calculating a motor control command value using a model matching compensator and a current limiter, and an actuator for turning the motor control command value. Motor drive means by a motor drive circuit that converts the command current into six command currents.

FIG. 3 is a control block diagram of the steer-by-wire system to which the first embodiment apparatus is applied.
First, the steer-by-wire system is divided into a steering reaction force side having the steering reaction force device controller 10 and the steering reaction force actuator 2, and a steering side having the steering device controller 18 and the steering actuator 6. It is done.

  The steering reaction device controller 10 feeds back only the estimated disturbance value from the steering device controller 18 from the steering side to the steering reaction force side, and the actual steering angle from the steering actuator 6 and the steering reaction force. The actual steering angle from the force actuator 2 is input. Then, the command current is output to the steering reaction force actuator 2 and the target turning angle is output to the turning device controller 18.

  The steering reaction force actuator 2 inputs a command current from the steering reaction force device controller 10 and a steering force from the driver. Then, the actual steering angle is output to the steering reaction force controller 10.

  The steering device controller 18 inputs the target turning angle from the steering reaction force device controller 10 and the actual turning angle from the turning actuator 6. Then, the command current is output to the steering actuator 6 and the estimated disturbance value is output to the steering reaction force device controller 10.

  The steering actuator 6 receives a command current from the steering device controller 18. Then, the actual turning angle is output to the steering reaction force device controller 10 and the steering device controller 18.

FIG. 4 is a block diagram of the steering reaction force control system showing the motor control command value calculation means of the steering reaction force device controller 10 of the first embodiment.
First, the steering reaction force controller 10 includes a steering input equivalent torque Ts calculation unit, a steering output equivalent torque Tf calculation unit, a disturbance equivalent torque To calculation unit, and a first limiter processing unit 10m. And a second limiter processing unit 10n.

  The calculation portion for the steering input equivalent torque Ts is obtained by multiplying the actual steering angle θs by the gain Ka to obtain the torque Ta, the differentiator 10b for time-differentiating the actual steering angle θs, and the actual steering angle θs. A gain setting unit 10c that obtains torque Tas by multiplying the differential value by gain Kas, and an adder 10d that adds torque Ta and torque Tas to calculate torque Ts corresponding to steering input.

  The steering output equivalent torque Tf calculation unit includes a differencer 10e that calculates a steering angle difference θts between a target steering angle θta and an actual steering angle θt, and a torque obtained by multiplying the steering angle difference θts by a gain Kfa. A gain setting device 10f for obtaining Tfa, a differentiator 10g for differentiating the turning angle difference θts with respect to time, a gain setting device 10h for obtaining the torque Tfas by multiplying the differential value of the turning angle difference θts by the gain Kfas, and the torque Tfa An adder 10i for adding the torque Tfas to calculate the torque Tf corresponding to the turning output.

  The disturbance equivalent torque To calculation unit includes a gain setting unit 10j that calculates the disturbance equivalent torque To by multiplying the steering side disturbance estimated value Tg by a gain Ko.

  The first limiter processing unit 10m performs a limiter process on the steering input equivalent torque Ts to create a steering input equivalent torque limit value Ts (lmit).

  The second limiter processing unit 10n adds the steering output equivalent torque Tf and the disturbance equivalent torque To by the adder 10p, and the steering input equivalent torque limiter value to the added value (Tf + To) by the adder 10q. A limiter process is performed on the value (Ts + Tf + To) obtained by adding Ts (lmit) to calculate the motor control command value Tms.

FIG. 5 is a block diagram of a turning angle control system that employs a robust model matching method in the first embodiment. Here, the “robust model matching method” means that the dynamic characteristics of the vehicle to be controlled are set in advance using a reference model (for example, the steering response characteristics of the yaw rate and lateral acceleration) to minimize the effects of modeling errors and disturbances. This is a technique for controlling to match a preset norm model while suppressing to the limit.
First, the steering device controller 18 includes a model matching compensator 18a, a robust compensator 18b (disturbance compensator), a difference unit 18c, and a current limiter 18d.

  The model matching compensator 18a is a feedforward compensator that inputs a command motor angle and an actual motor angle and outputs a motor command current that matches a desired response characteristic given in advance.

  The robust compensator 18b takes in a command current that is an input to the controlled object and an actual motor angle that is an output from the controlled object, and outputs a disturbance estimated value obtained by estimating a control inhibition factor including a modeling error as a disturbance. It is a compensator. Note that the estimated disturbance value from the robust compensator 18b is used for steering reaction force control as described above.

  The difference unit 18c subtracts the estimated disturbance value from the robust compensator 18b from the motor command current from the model matching compensator 18a to generate a command current in which the disturbance is canceled.

  The current limiter 18d outputs the command current as it is to the controlled steering actuator 6 when the command current from the differentiator 18c is equal to or less than the limit current, and outputs the limit current when the command current exceeds the limit current. Output to the rudder actuator 6.

  Next, the operation will be described.

[Steering reaction force control processing]
FIG. 6 is a flowchart showing the flow of the steering reaction force control process executed by the steering reaction force device controller 10 of the first embodiment, and each step will be described below.

  In step S1, the reaction force motor angle θms from the steering reaction force motor angle sensor 9, the vehicle speed V from the vehicle speed sensor 11, the yaw rate Y from the yaw rate sensor 12, the lateral acceleration G from the lateral acceleration sensor 13, The disturbance estimated value Tg from the steering device controller 18 is read, and the process proceeds to step S2.

  In step S2, the reaction force motor angle θms is divided by the reduction gear ratio Rs between the motor and the steering column shaft to convert the steering wheel angle θs (= θms / Rs: actual steering angle θs), and the process proceeds to step S3.

  In step S3, it is determined whether or not the steering wheel angle θs converted in step S2 is greater than or equal to the maximum value θmax determined by the displaceable amount of the steered side displacement member. If YES, the process proceeds to step S18 and NO. If so, the process proceeds to step S4. When the steering gear ratio between the steering side and the steered side is variable, the maximum value θmax is determined in consideration of the gear ratio.

  In step S4, the steering wheel angle θs obtained in step S2 is time-differentiated to calculate the steering wheel angular velocity dθs / dt, and the process proceeds to step S5 (differentiator 10b).

  In step S5, an angle term torque Ta (= Ka × θs) is obtained by multiplying the steering wheel angle θs obtained in step S2 by a gain Ka calculated based on a target response and an attenuation coefficient determined in advance by the vehicle speed V. And the process proceeds to step S6 (gain setting device 10a).

  In step S6, each speed term torque Tas (= Kas) is obtained by multiplying the steering wheel angular velocity dθs / dt obtained in step S4 by a gain Kas calculated based on a target response and a damping coefficient determined in advance by the vehicle speed V. Xdθs / dt) is calculated, and the process proceeds to step S7 (gain setting device 10c).

  In step S7, the angular term torque Ta obtained in step S5 and the angular velocity term torque Tas obtained in step S6 are added to calculate a steering input equivalent torque Ts, and the process proceeds to step S8 (adder 10d). .

  In step S8, the vehicle speed V, the steering wheel angle θs, and the limit value Ls obtained from the road surface friction coefficient estimated from the vehicle speed V, the yaw rate Y, the lateral acceleration G, and the like, are equivalent to the steering input obtained in step S7. The torque Ts is subjected to a limiter process, and the process proceeds to step S9 (first limiter processing unit 10m).

  In step S9, the turning angle difference θts between the target turning angle θta and the actual turning angle θt is taken, and the process proceeds to step S10 (difference device 10e).

  In step S10, the steering angle difference θts is time-differentiated to calculate a steering angle difference differential value dθts / dt, and the process proceeds to step S11 (differentiator 10g).

  In step S11, the angle difference term torque Tfa (= Kfa × θts) is calculated by multiplying the steering angle difference θts obtained in step S9 by the gain Kfa determined according to the vehicle speed V, and the process proceeds to step S12. (Gain setting device 10f).

  In step S12, the steering angle difference differential value dθts / dt obtained in step S10 is multiplied by a gain Kfas determined according to the vehicle speed V to obtain an angle difference term differential term torque Tfas (= Kfas × dθts / dt). Then, the process proceeds to step S13 (gain setting device 10h).

  In step S13, the angle difference term torque Tfa obtained in step S11 and the angle difference term differential term torque Tfas obtained in step S12 are added to calculate a torque Tf (= Tfa + Tfas) corresponding to the turning output. The process proceeds to step S14 (adder 10i).

  In step S14, the disturbance equivalent value Tg estimated by the robust compensator 18b in the robust model matching method employed in the turning angle control is multiplied by the gain Ko to obtain the torque equivalent to the disturbance To (= Ko × Tg). Then, the process proceeds to step S15 (gain setting device 10j).

  In step S15, the steering input equivalent torque Ts obtained in step S8, the steering output equivalent torque Tf obtained in step S13, and the disturbance equivalent torque To obtained in step S14 are added. Total torque Tt (= Ts + Tf + To) is calculated, and the process proceeds to step S16 (adders 10p, 10q).

  In step S16, the total torque Tt obtained in step S15 is subjected to a limiter process with a limit value Lm predetermined for protecting the motor, a motor control command value Tms is calculated, and the process proceeds to step S17 (second step). Limiter processing unit 10n).

  In step S17, motor control of the steering reaction force actuator 2 is executed based on the motor control command value Tms calculated in step S16, and the process proceeds to return.

  In step S18, when it is determined in step S3 that the steering wheel angle θs is equal to or larger than the maximum value θmax, limiter processing is performed on the steering wheel angle θs with the limit value Lm, and the process proceeds to step S19.

  In step S19, the limit value Lm obtained in step S18 is set to the motor control command value Tms, so that the steering wheel angle θs is kept constant at the maximum value θmax and the steering reaction force is pulsated compared to that during normal control. Then, the process proceeds to step S17.

[Steering reaction force control action]
When the steering wheel angle θs is less than the maximum value θmax determined by the displaceable amount of the steered side displacement member, in the flowchart of FIG. 6, step S1, step S2, step S3, step S4, step S5, step S6, step S6. Proceeding to step S7, in step S7, the torque term torque Ta corresponding to the steering input is calculated by adding the angular term torque Ta obtained in step S5 and the angular velocity term torque Tas obtained in step S6. Then, the process proceeds from step S7 to step S8. In step S8, steering input is performed with the vehicle speed V, the steering wheel angle θs, and the limit value Ls obtained from the road surface friction coefficient estimated from the vehicle speed V, the yaw rate Y, the lateral acceleration G, and the like. A limiter process is applied to the torque Ts.

  Therefore, when the steering wheel angle θs and the steering wheel angular velocity dθs / dt increase, the steering reaction force is prevented from becoming too large, and the steering wheel 1 cannot be increased or is difficult to increase. It is possible to prevent the steering reaction force characteristic according to the vehicle characteristic. Further, in addition to the vehicle speed V and the steering wheel angle θs, the limit value Ls is given as a variable value in consideration of the road surface condition by estimating the road surface friction coefficient, so that the torque Ts corresponding to the steering input more faithful to the vehicle characteristics is obtained. be able to.

  From step S8, the process proceeds from step S9 to step S10, step S11, step S12, and step S13. In step S13, the angle difference term torque Tfa obtained in step S11 and the angle difference obtained in step S12. By adding the term differential term torque Tfas, the torque Tf corresponding to the turning output is calculated.

  Further, from step S13, the process proceeds to step S14, where the disturbance estimated value Tg estimated by the robust compensator 18b in the robust model matching technique employed in the turning angle control is multiplied by the gain Ko to generate a torque corresponding to the disturbance. To is calculated.

  Therefore, even if the control on the steered side has strong stability against disturbances, and there is little difference between the target turning angle and the actual turning angle even when a disturbance is applied from the road surface etc., the disturbance of the robust model matching method Disturbance estimated by the compensator (In the angle control on the turning side, the disturbance is estimated to match the target turning angle and the actual turning angle, and the command current is set so as to cancel the estimated disturbance. Therefore, the disturbance can be estimated even if there is almost no difference between the target turning angle and the actual turning angle.) Only the feedback to the steering reaction force side is used to calculate the steering reaction force. Thus, the steering reaction force against the disturbance can be simulated with higher accuracy.

  In addition, the disturbance compensator of the robust model matching method used in the turning angle control is used to estimate the disturbance while estimating the road surface reaction force using the difference between the target turning angle and the actual turning angle. Therefore, it is possible to estimate the disturbance reaction and to simulate the steering reaction force more faithful to the vehicle characteristics.

  Furthermore, since the disturbance is estimated using a disturbance compensator in the robust model matching method employed in the turning angle control, it is not necessary to provide a disturbance estimator separately for steering reaction force control.

  From step S14, the process proceeds from step S15 to step S16 to step S17. In step S15, the torque corresponding to the steering input, the torque corresponding to the steering output Tf, and the disturbance equivalent torque To are added to obtain the total torque. Tt is calculated, and in step S16, the total torque Tt is subjected to a limiter process with a limit value Lm determined in advance for motor protection to calculate a motor control command value Tms. In step S17, the motor control command value Tms is calculated. Based on this, motor control of the steering reaction force actuator 2 is executed.

  Therefore, when a motor control command value greater than the motor rating of the steering reaction force actuator 2 is calculated, the motor control command value is subjected to a limiter process to prevent an excessive current from flowing through the motor. Can be protected.

  On the other hand, when the steering wheel angle θs is equal to or larger than the maximum value θmax determined by the displaceable amount of the steered side displacement member, in the flowchart of FIG. 6, step S1, step S2, step S3, step S18, step S19, step In step S18, the limiter process is performed with the limit value Lm for the steering wheel angle θs. In step S19, the steering wheel angle θs is made constant at the maximum value θmax, and the steering reaction force is normally controlled. It is made to become large in a pulse compared with the time.

  Therefore, by increasing the steering reaction force in a pulse manner as compared with the normal control, it is possible to notify the driver that the steering angle is the maximum, and to prevent the driver from turning the steering wheel 1 too much.

  Further, since the steering wheel command value is determined by the steering wheel angle θs, it is possible to prevent the steering-side displacement member from colliding with the stopper by applying a limiter process to the steering wheel angle θs.

Next, the effect will be described.
In the vehicle steering control device of the first embodiment, the following effects can be obtained.

  (1) A steer-by-wire system in which there is no mechanical connection between a steering reaction device 3 having a steering wheel 1 and a steering reaction force actuator 2 and a steering device 7 having steered wheels 4 and 5, In the vehicle steering control device including the steering reaction force device controller 10 that calculates the steering reaction force command value to the steering reaction force actuator 2 by adding the equivalent amount of disturbance to the input / output amount, the steering reaction force The apparatus controller 10 sets the estimated disturbance estimated by using the disturbance compensator employed in the turning angle control as a disturbance equivalent, and feeds back only the estimated disturbance equivalent from the steered side to the steering reaction force side. Therefore, even if the steered side control has strong stability against disturbance and there is almost no difference between the target turning angle and the actual turning angle, the steering reaction force command value can be calculated accurately with the equivalent of disturbance. The steering reaction force against the minute can be simulated. In addition, it is not necessary to provide a separate disturbance estimator for steering reaction force control.

  (2) Since the disturbance compensator is a robust compensator 18b used in the robust model matching method adopted in the turning angle control for the purpose of minimizing the influence of modeling error and disturbance, This makes it possible to estimate the disturbance with high accuracy and to simulate the steering reaction force that is more faithful to the vehicle characteristics.

  (3) Since the steering reaction force actuator 2 is a motor with a clutch, it is possible to prevent an excessive steering reaction force from being generated by disengaging the clutch when the motor runs away.

  (4) A vehicle speed sensor 11 for detecting a vehicle speed and a steering reaction force motor angle sensor 9 for detecting a steering angle are provided, and the steering reaction force device controller 10 includes a steering wheel angle θs and an actual steering angle. The limiter by the first limiter processing unit 10m is obtained by multiplying the steering wheel angular velocity dθs / dt, which is the actual steering angular velocity, by the gain Ka and Kas calculated so as to obtain a target response and an attenuation coefficient corresponding to the vehicle characteristics. The first limiter processing unit 10m determines the limit value Ls according to the vehicle speed V and the steering wheel angle θs, so that the limit value Ls is not a constant value but the vehicle speed V. It becomes a variable value according to the steering wheel angle θs, and can be a steering reaction force according to vehicle characteristics.

  (5) A road surface friction coefficient estimating means for estimating the road surface friction coefficient is provided, and the first limiter processing unit 10m determines the road surface condition in order to determine the limit value Ls according to the vehicle speed V, the steering wheel angle θs, and the road surface friction coefficient. By taking the variable limit value Ls into consideration, it is possible to obtain a steering reaction force that is more faithful to vehicle characteristics.

  (6) The steering reaction force controller 10 includes a steering input equivalent torque Ts subjected to the limiter processing by the first limiter processing unit 10m, a difference θts between the target turning angle and the actual turning angle, and the difference between them. Steering output equivalent torque Tf calculated by multiplying each of the time differential values dθts / dt by gains Kfa, Kfas corresponding to vehicle speed V, disturbance equivalent torque To estimated using robust compensator 18b, In addition, since the limiter process is further performed by the second limiter processing unit 10n on the steering reaction force command value Tt to which is added, it is possible to prevent the excessive current from flowing to the motor of the steering reaction force actuator 2 and protect the motor. it can.

  (7) When the steering wheel angle θs reaches the maximum angle θmax, the steering reaction force device controller 10 keeps the steering wheel angle θs constant at the maximum angle θmax and increases the steering reaction force in a pulsed manner. Therefore, it is possible to notify the driver that the steering angle is the maximum steering angle and to prevent the driver from overcutting the steering wheel 1 and to prevent the displacement member on the steering side from colliding with the stopper. It becomes possible to do.

First, the configuration will be described.
FIG. 7 is a diagram illustrating an overall configuration of a steering reaction force control system and a turning angle control system of the vehicle steering control device according to the second embodiment.

  In addition to the configuration of the steering reaction force device controller 10 of the first embodiment shown in FIG. 2, the steering reaction force device controller 21 of the second embodiment determines whether the steered wheels 4 and 5 are in contact with an obstacle such as a curb. This embodiment differs from the first embodiment in that an obstacle contact determination unit is provided.

  The obstacle contact determination means determines whether the steered wheels 4 and 5 are based on the steered angle difference θts, which is the absolute value of the difference between the target steered angle θta and the actual steered angle θt, and the steered side motor current value. It is a means for determining whether or not the vehicle is hitting an obstacle such as a curb.

  Next, the operation will be described.

[Obstacle contact determination control processing]
FIG. 8 is a flowchart showing the flow of the obstacle contact determination control process executed by the steering reaction force controller 10a of the second embodiment, and each step will be described below.

  In step S21, the actual steering angle θs from the steering reaction force motor angle sensor 9, the vehicle speed V from the vehicle speed sensor 11, the yaw rate Y from the yaw rate sensor 12, the lateral acceleration G from the lateral acceleration sensor 13, and the rolling The actual turning angle θt and the steering-side motor current value It from the steering motor angle sensor 17 are read, and the process proceeds to step S22.

  In step S22, the judgment value Ia of the steered side motor current value is determined from the road surface μ and the vehicle speed V estimated from the vehicle speed V, yaw rate Y, lateral acceleration G, etc. read in step S21, and the process proceeds to step S23.

  In step S23, a steering angle difference θts, which is an absolute value of the difference between the target turning angle θta determined according to the steering angle and the actual turning angle θt, is calculated, and the process proceeds to step S24.

  In step S24, it is determined whether or not the turning angle difference θts is greater than or equal to a determination value θa determined in consideration of a delay due to communication between the steering side and the turning side, a response delay with respect to the command, and the like. If YES, the process proceeds to step S25, and if NO, the process proceeds to return.

  In step S25, it is determined whether or not the actual turning angle θt has changed compared to the previous value. If YES, the process proceeds to step S26, and if NO, the process proceeds to step S27.

  In step S26, the timer counts up the time, and the process proceeds to step S28.

  In step S27, the timer value is cleared, and the process proceeds to return.

  In step S28, it is determined whether or not the value counted up in step S26 is equal to or longer than the determination time tit. If YES, the process proceeds to step S29. If NO, the process proceeds to step S30.

  In step S29, the first time determination flag is set, and the process proceeds to step S37.

  In step S30, the time determination first flag is cleared, and the process proceeds to return.

  In step S31, it is determined whether the steered side current value It is equal to or greater than the determination value Ia obtained in step S22. If YES, the process proceeds to step S32. If NO, the process proceeds to return.

  In step S32, the timer counts up the time, and the process proceeds to step S34.

  In step S33, the timer value is cleared, and the process proceeds to return.

  In step S34, it is determined whether or not the value counted up in step S32 is equal to or longer than the determination time tt. If YES, the process proceeds to step S35, and if NO, the process proceeds to step S36.

  In step S35, the time determination second flag is set, and the process proceeds to step S37.

  In step S36, the time determination second flag is cleared, and the process proceeds to return.

  In step S37, it is determined whether both the time determination first flag and the time determination second flag are set. If YES, the process proceeds to step S38, and if NO, the process proceeds to return.

  In step S38, an obstacle contact determination flag for determining that the steered wheels 4 and 5 are in contact with an obstacle such as a curb is set, and the process proceeds to return.

[Obstacle contact judgment control action]
When the turning angle difference θts is not less than the determination value θa and the actual turning angle θt does not change for the determination time tit or more, in the flowchart of FIG. 8, step S21 → step S22 → step S23 → step S24 → step S25 → The flow proceeds from step S26 to step S28 to step S29 to step S37. That is, in step S29, the time determination first flag is set.

  When the turning angle difference θts is equal to or larger than the determination value θa and the turning-side current value It is equal to or larger than the determination value Ia, in the flowchart of FIG. 8, step S21 → step S22 → step S23 → step S24 → step S31. → Step S32 → Step S34 → Step S35 → Step S37. That is, in step S35, the time determination second flag is set.

  In step S37, if both the time determination first flag and the time determination second flag are set, the process proceeds to step S38, and the obstacle contact determination flag is set.

[Steering reaction force control processing]
FIG. 9 is a flowchart showing the flow of the steering reaction force control process executed by the steering reaction force device controller 10a of the second embodiment, and each step will be described below.

  In step S41, it is determined whether the obstacle contact determination flag is set. If YES, the process proceeds to step S42, and if NO, the process proceeds to step S45.

  In step S42, it is determined whether or not the turning angle difference θts is greater than or equal to a value θb (θa> θb> 0) determined in consideration of the turning angle control accuracy and the like. If YES, the process proceeds to step S43, and if NO, the process proceeds to step S44.

  In step S43, a command current value is calculated so as to obtain a pulsed steering reaction force, and the process proceeds to step S46.

  In step S44, the obstacle contact flag determination flag is cleared, and the process proceeds to step S45.

  In step S45, a command current value for normal control is calculated, and the process proceeds to step S46.

  In step S46, the command current value calculated in steps S43 and S45 is subjected to a limiter process with a limit value Lsm determined in advance for motor protection, and the process proceeds to step S47.

  In step S47, motor control of the steering reaction force actuator 2 is executed based on the command current value after the limiter process, and the process proceeds to return.

[Steering reaction force control action]
When the obstacle contact determination flag is set and the turning angle difference θts is equal to or larger than θb, the process proceeds to step S41 → step S42 → step S43 → step S46 → step S47 in the flowchart of FIG. It becomes a flow. That is, in step S43, the command current value is determined so as to be a pulsed steering reaction force, and in step S47, the motor of the steering reaction force actuator 2 is driven so as to be a pulsed steering reaction force.

  Therefore, when the steered wheels 4 and 5 are in contact with an obstacle such as a curb when the steering wheel 1 is further steered, and the steered wheels 4 and 5 cannot be further steered, a pulse-like steering reaction is performed. By generating the force, it is possible to inform the driver that steering is impossible and to prevent the steering wheel 1 from being overcut.

  On the other hand, when the turning angle difference θts is smaller than θb, the flow proceeds to step S41 → step S44 → step S45 → step S46 → step S47 in the flowchart of FIG. That is, the obstacle contact determination flag is cleared in step S44, the command current value for normal control is calculated in step S45, and the steering reaction force actuator is calculated based on the command current value for normal control in step S47. 2 motors are driven.

  Therefore, when the driver steers back the steering wheel 1 and the target turning angle θta and the actual turning angle θt are equal to each other, the normal steering control is restored, so that the steering is turned from turning back to turning back. Switching of the steering reaction force control in the case of transition can be performed smoothly.

[Steering angle control processing]
FIG. 10 is a flowchart showing the flow of the turning angle control process executed by the turning device controller 21 of the second embodiment, and each step will be described below.

  In step S51, the actual turning angle θt from the steering motor angle sensor 17 and the target turning angle θta from the steering reaction force controller 10a are read, and the process proceeds to step S52.

  In step S52, it is determined whether the obstacle contact determination flag is set. If YES, the process proceeds to step S53, and if NO, the process proceeds to step S56.

  In step S53, it is determined whether or not the turning angle difference θts is greater than or equal to a value θb (θa> θb> 0) determined in consideration of turning angle control control or the like. If YES, the process moves to step S54, and if NO, the process moves to step S55.

  In step S54, the target turning angle θta is set to the actual turning angle θt, and the process proceeds to step S56.

  In step S55, the obstacle contact determination flag is cleared, and the process proceeds to step S56.

  In step S56, normal turning angle control is performed to calculate a command current value, and the process proceeds to step S57. However, when the obstacle contact determination flag is set, the target turning angle θta is set to the actual turning angle θt as set in step S54, and the obstacle contact determination flag is not set. Is according to the steering angle.

  In step S57, the command current value calculated in steps S54 and S56 is subjected to limiter processing with a limit value Ltm determined in advance for motor protection, and the process proceeds to step S58.

  In step S58, motor control of the steering device actuator 6 is executed based on the command current value after the limiter process, and the process proceeds to return.

[Steering angle control action]
When the obstacle contact determination flag is set and the turning angle difference θts is equal to or greater than θb, in the flowchart of FIG. 10, step S51 → step S52 → step S53 → step S54 → step S56 → step S57. → The flow proceeds to step S58. That is, in step S54, the actual turning angle θt is set to the target turning angle θta, and in step S56, the motor of the steering device actuator 6 is driven using the actual turning angle θt as the target turning angle θta.

  Therefore, when the steered wheels 4 and 5 are in contact with an obstacle such as a curb when the steering wheel 1 is further steered and the steered wheels 4 and 5 cannot be further steered, the actual steered angle θt By setting to the target turning angle θta, it is possible to prevent excessive current from flowing to the motor of the steering device actuator 6.

  On the other hand, when the turning angle difference θts is smaller than θb, in the flowchart of FIG. 10, the flow proceeds from step S51 → step S52 → step S53 → step S55 → step S56 → step S57 → step S58. . That is, the obstacle contact determination flag is cleared in step S55, and the steering device actuator 6 is driven based on the command current value for normal control in step S58.

  Therefore, when the driver steers back the steering wheel 1 and the target turning angle θta and the actual turning angle θt are equal to each other, the normal steering control is restored, so that the steering is turned from turning back to turning back. It is possible to smoothly switch the steering angle control when the transition is made.

Next, the effect will be described.
In the vehicle steering control device of the second embodiment, in addition to the effects (1) to (7) of the first embodiment, the effects listed below can be obtained.

  (8) When the steered wheels 4 and 5 are in contact with an obstacle, the steering reaction force controller 10a performs processing so as to increase the steering reaction force in a pulse manner. It is possible to prevent the steering wheel 1 from being overcut.

  (9) The steering reaction force controller 10a switches to normal steering reaction force control when the turning angle difference θts becomes smaller than θb after the steered wheels 4 and 5 are in contact with the obstacle. It is possible to smoothly switch the steering reaction force control when the shift from the increase to the return is made.

First, the configuration will be described.
FIG. 11 is an overall view showing a steer-by-wire system to which the vehicle steering control device of the third embodiment is applied. FIG. 12 is an overall view of the steering reaction force control system and the turning angle control system of the vehicle steering control device of the third embodiment. It is a figure which shows a structure.

  The steer-by-wire system of the third embodiment includes an obstacle detection radar 31, a reaction force motor temperature sensor 32, and a steering motor temperature sensor 33 in addition to the configuration of the first embodiment shown in FIG. This differs from the first embodiment.

  As the obstacle detection radar 31, a laser radar, a millimeter wave radar, or the like is used, and detects an obstacle in front of the vehicle. The reaction force motor temperature sensor 32 and the turning motor temperature sensor 33 detect the motor temperatures of the steering reaction force actuator 2 and the turning actuator 6.

  The steering reaction force controller 30 according to the third embodiment includes a motor overheat determination unit and an obstacle avoidance steering determination unit in addition to the configuration of the first embodiment illustrated in FIG. Further, the steering device controller 34 includes a motor overheat determination means.

  The motor overheat determination means determines whether or not the motor is in an overheated state from the reaction force motor temperature sensor 32 and the steering motor temperature sensor 33. The obstacle avoidance steering determination means determines whether or not the steering is avoidable by the driver.

  Next, the operation will be described.

[Motor overheat protection control processing]
FIG. 13 is a flowchart showing the flow of the motor overheat protection control process executed by the steering reaction force controller 30 and the steering device controller 34 according to the third embodiment. Each step will be described below.

  In step S 61, the actual steering angle θs and actual steering angular velocity dθs / dt from the steering reaction force motor angle sensor 9, the temperature ts of the steering reaction force side motor from the reaction force motor temperature sensor 32, and the vehicle speed sensor 11 The vehicle speed V, the obstacle detection flag determined in advance by the detection signal from the obstacle detection radar 31, the actual turning angle θt from the turning motor angle sensor 17, and the turning side motor overheat protection flag ( The flag indicating whether or not it is in the overheat protection state is read, and the process proceeds to step S62.

  In step S62, it is determined from the actual steering angle θs, the actual steering angular velocity dθs / dt, the vehicle speed V, and the obstacle detection flag whether the driver's steering is for obstacle avoidance. If YES, the process proceeds to step S63, and if NO, the process proceeds to step S64.

  In step S63, an obstacle avoidance flag is set, and the process proceeds to step S65.

  In step S64, the obstacle avoidance flag is cleared, and the process proceeds to step S67.

  In step S65, it is determined whether the steered side motor overheat protection flag is set. If YES, the process proceeds to step S66, and if NO, the process proceeds to step S70.

  In step S66, normal control is performed, and the process proceeds to return.

  In step S67, it is determined whether the steered side motor overheat protection flag is set. If YES, the process proceeds to step S68, and if NO, the process proceeds to step S70.

  In step S68, it is determined whether or not the temperature ts of the steering reaction force side motor is equal to or higher than a value ta determined in advance from the rated value of the motor. If yes, then continue with S69, otherwise continue with step S71.

  In step S69, an unillustrated lamp or the like provided in the passenger compartment is lit to issue a warning to the driver, and the process proceeds to step S71.

  In step S70, it is determined whether the temperature ts of the steering reaction force side motor is equal to or higher than a value ta determined in advance from the rated value of the motor. If yes, then continue with S71, otherwise continue with step S77.

  In step S71, the steering reaction force side motor overheat protection flag is set, and the process proceeds to step S72.

  In step S72, it is determined whether or not the gain multiplied by the steering reaction force command value has reached the target value. If YES, the process proceeds to step S73, and if NO, the process proceeds to step S74. The target value is set to be reduced compared to the current value during normal control when the steering reaction force side is overheated, and compared with the current value during normal control when the steering side is overheated only. When the both of the steering reaction force side and the steered side are overheated, the current value is set to be lower than the current value during normal control.

  In step S73, the current control is maintained and the process proceeds to return.

  In step S74, it is determined whether or not the current position is a predetermined reference position. If YES, the process proceeds to step S75, and if NO, the process proceeds to step S76. Note that the reference position is variable depending on the vehicle speed V, and the actual turning angle θt becomes the reference position near the vehicle speed zero. When the vehicle speed V increases and the influence of the self-aligning torque is large, the steering angle center (the steering angle Zero angle) is the reference position.

  In step S75, control is performed to gradually change the gain applied to the steering reaction force side motor current so as to approach the target value, and the process proceeds to step S72.

  In step S76, the current control is maintained without changing the gain, and the process proceeds to step S72.

  In step S77, it is determined whether or not the steering reaction force side motor overheat protection flag is set. If YES, the process proceeds to step S78, and if NO, the process proceeds to step S83.

  In step S78, it is determined whether the gain multiplied by the steering reaction force command value has reached the target value. If YES, the process proceeds to step S79, and if NO, the process proceeds to step S80.

  In step S79, the motor overheat protection flag on the steering reaction force side is cleared, and the routine proceeds to return.

  In step S80, it is determined whether or not the current position is a predetermined reference position. If YES, the process proceeds to step S81. If NO, the process proceeds to step S82.

  In step S81, control for changing the gain multiplied by the steering reaction force command value little by little to bring it closer to the target value is performed, and the process proceeds to step S78.

  In step S82, the current control is maintained without changing the gain, and the process proceeds to step S78.

  In step S83, if the warning lamp is lit, the lamp is turned off and the process proceeds to return.

[Motor overheat protection control function]
When the driver is steering for obstacle avoidance and the motor overheat protection flag on the steered side is set, in the flowchart of FIG. 13, step S61 → step S62 → step S63 → step S65. → The flow proceeds to step S66. That is, since normal control is performed in step S66, the driver can steer for obstacle avoidance.

  When the driver is steering for obstacle avoidance and the motor overheat protection flag on the steered side is not set, the process proceeds from step S61 to step S62 to step S63 to step S65 to step S70. .

  If the motor temperature ts of the steering reaction force actuator 2 is greater than or equal to ta in step S70, the process proceeds from step S71 to step S72 until the gain multiplied by the steering reaction force command value reaches the target value in step S72. Then, step S72 → step S74 → step S75 is repeated, and control for changing the gain little by little to approach the target value is performed. That is, the target current value of the steering reaction force command value is reduced compared to the current value during normal control, and the steering reaction force is controlled so as to gradually approach the target current value. A sudden change in reaction force can be prevented.

  In step S74, if the current position is not the reference position, the process proceeds to step S76, and the current control is maintained without changing the gain. Can be prevented.

  In step S70, when the motor temperature ts of the steering reaction force actuator 2 is lower than ta, the process proceeds to step S77.

  In step S77, if the steering reaction force side motor overheat protection flag is set, the process proceeds from step S77 to step S78. In step S78, until the gain multiplied by the steering reaction force command value reaches the target value, step S78 → step S80 → step S81 is repeated, and the gain is changed little by little so as to approach the target value. That is, since the steering reaction force is controlled so as to gradually approach the target current value, a sudden change in the steering reaction force can be prevented while protecting the motor.

  In step S80, if the current position is not the reference position, in step S82, the current control is maintained without changing the gain, thereby preventing a sudden change in the steering reaction force at the time of additional steering or switchback steering. it can.

  If the steering reaction force side motor overheat protection flag is not set in step S77, the lamp is turned off in step S83, and normal control is performed.

  If the driver is not steering for obstacle avoidance, the process proceeds from step S61 to step S62 to step S64 to step S67.

  In step S67, if the steered-side motor overheat protection flag is set, the process proceeds to step S68. If the motor temperature ts of the steering reaction force actuator 2 is equal to or higher than ta, the process proceeds to step S69. After the lamp is turned on to alert the driver, the process proceeds from step S71 to step S72. In step S72, since both the steering side motor and the steered side motor are overheated, the target current value of the steering reaction force command value is set smaller than the current value during normal control.

  In step S68, when the motor temperature ts of the steering reaction force actuator 2 is lower than ta, the process proceeds from step S71 to step S72. In step S72, since only the steered motor is overheated, the target current value of the steering reaction force command value is set higher than the current value during normal control. That is, it is possible to increase the driver's steering feeling by increasing the steering reaction force, and to reduce the region where it is difficult for the steering side to follow the steering.

  In step S67, when the motor overheat protection flag on the steered side is not set, the process proceeds to step S70.

  If the motor temperature ts of the steering reaction force actuator 2 is greater than or equal to ta in step S70, the process proceeds from step S71 to step S72. In step S72, since only the steering side motor is overheated, the target current value of the steering reaction force command value is set smaller than the current value during normal control, and the motor can be overheat protected.

[Steering angle control processing]
FIG. 14 is a flowchart showing the flow of the turning angle control process executed by the turning device controller 34 of the third embodiment, and each step will be described below.

  In step S91, the motor temperature tt is read from the steering motor temperature sensor 33 and the obstacle avoidance flag is read from the steering reaction force device controller 30, and the process proceeds to step S92.

  In step S92, it is determined whether the obstacle avoidance flag is set. If YES, the process moves to step S93, and if NO, the process moves to step S94.

  In step S93, normal control is performed, and the process proceeds to step S return.

  In step S94, it is determined whether the temperature tt of the steered side motor is equal to or higher than a value tb determined in advance from the rated value of the motor. If YES, the process proceeds to step S95, and if NO, the process proceeds to S101.

  In step S95, the motor overheat protection flag on the steered side is set, and the process proceeds to step S96.

  In step S96, it is determined whether or not the gain multiplied by the steering command value has reached the target value. If YES, the process proceeds to step S97, and if NO, the process proceeds to step S98. The target value is set so as to be reduced compared to the current value during normal control.

  In step S97, the current control is performed, and the process proceeds to return.

  In step S98, it is determined whether or not the current position is a predetermined reference position. If YES, the process proceeds to step S99, and if NO, the process proceeds to step S100.

  In step S99, control is performed to gradually change the gain applied to the steered side motor current so as to approach the target value, and the process proceeds to step S96.

  In step S100, the current control is maintained without changing the gain, and the process proceeds to step S96.

  In step S101, it is determined whether the motor overheat protection flag on the steered side is set. If YES, the process proceeds to step S102, and if NO, the process proceeds to step S106.

  In step S102, it is determined whether or not the current position is a predetermined reference position. If YES, the process proceeds to step S103, and if NO, the process proceeds to step S1105.

  In step S103, the steered side motor command value is used for normal control, and the process proceeds to step S104.

  In step S104, the motor overheat protection flag on the steered side is cleared, and the process proceeds to return.

  In step S105, the current control is maintained without changing the gain, and the process proceeds to step S102.

  In step S106, normal control is performed, and the process proceeds to return.

[Steering angle control action]
When the obstacle avoidance flag is set, the process proceeds from step S91 to step S92 to step S93 in the flowchart of FIG. 14, and normal control is performed in step S93. That is, responsiveness and followability during normal control are ensured.

  If the obstacle avoidance flag is not set, the process proceeds from step S91 to step S92 to step S94. If the motor temperature tt of the steering actuator 6 is equal to or higher than tb in step S94, step S95 → Proceed to step S96. On the other hand, if the motor temperature tt of the steering actuator 6 is smaller than tb in step S94, the process proceeds to step S101, and then, if the motor overheat protection flag on the steering side is not set, Proceeding to step S106, normal control is performed.

  In Step S96, Step S98 → Step S99 is repeated until the gain multiplied by the steering command value reaches the target value, and the gain is changed little by little so as to approach the target value. That is, the target current value of the turning angle command value is reduced compared to the current value during normal control, and the turning angle is controlled so as to gradually approach the target current value. It is possible to prevent excessive follow-up and response deterioration.

  If the current position is not the reference position in step S98, the current control is maintained in step S100 without changing the gain. In step S96, when the gain reaches the target value, the process proceeds to step S97, and the current control is maintained.

  If the steer-side motor overheat protection flag is set in step S101, the process proceeds to step S102, and the gain is not changed in step S105 until the current position becomes the reference position in step S102. Maintain current control.

  When the current position becomes the reference position in step S102, the process proceeds from step S103 to step S104. In step S103, the steered side motor command value is used for normal control. In step S104, the steered side motor is overheated. Clear the protection flag. That is, immediately following the normal target current value can ensure followability and responsiveness.

Next, the effect will be described.
In the vehicle steering control device of the third embodiment, in addition to the effects (1) to (7) of the first embodiment, the effects listed below can be obtained.

  (10) The steering reaction force device controller 30 sets the target current value of the steering reaction force command value to be reduced compared to the current value during normal control when the motor of the steering reaction force actuator 2 is overheated. Since the gain multiplied by the reaction force command value is changed little by little, the motor can be protected from overheating. In addition, it is possible to suppress a sense of discomfort given to the driver by preventing a sudden change in the steering reaction force.

  (11) When the motor of the steering actuator 6 is overheated, the steering device controller 34 is set so that the target current value of the steering angle command value is reduced compared to the current value at the time of normal control. Since the gain multiplied by the command value is changed little by little, the current value of the motor is reduced little by little, so that it is possible to protect the motor from overheating. In addition, it is possible to prevent rapid follow-up / responsiveness deterioration.

  (12) When the motor of the steering actuator 6 is overheated, the steering reaction force device controller 30 sets a target current value of the steering reaction force command value higher than that during normal control, and sets a gain by which the steering reaction force command value is multiplied. Since the steering reaction force is changed little by little, it is possible to increase the driver's steering feeling by increasing the steering reaction force, and to reduce the region where it is difficult for the steering side to follow the steering.

  (13) When the steering reaction force actuator controller 30 releases the current value reduction control when the steering reaction force actuator 2 is overheated, the steering reaction force device controller 30 changes the gain multiplied by the steering reaction force command value little by little. This can prevent the driver from feeling uncomfortable.

  (14) The steering device controller 34 immediately returns the target current value of the steering angle command value to the current value at the time of normal control when canceling the current value reduction control when the steering actuator 6 is overheated. Trackability and responsiveness can be secured.

  (15) When the turning angle is near the reference position, the steering reaction force controller 30 switches between normal control and current value reduction control. In turning-up and turning-back steering, a sudden change in the steering reaction force can be prevented, and the uncomfortable feeling given to the driver can be reduced.

  (16) When obstacle avoidance steering is performed, the motor current value of the steering actuator 6 is not decreased, and the motor current value of the steering reaction force actuator 2 is not increased. In addition to making it possible for the driver to steer for obstacle avoidance, the steered side can also be steered with normal response and followability. Moreover, since it corresponds to the steering for temporary obstacle avoidance, even if the motor is in an overheated state, the possibility that the motor is broken is reduced.

  (17) When the motors of the steering reaction force actuator 2 and the steering actuator 6 are both overheated, the steering reaction device controller 30 turns on the lamp and issues a warning to the driver. Then, the steering reaction force controller 30 and the steering device controller 34 perform the current value reduction control after the lamp is lit. That is, in the current value reduction control when the motor is overheated, the driver can be notified in advance by issuing a warning to the driver, for example, by turning on a lamp.

(Other examples)
As mentioned above, although the vehicle steering control apparatus of the present invention has been described based on the first to third embodiments, the specific configuration is not limited to these first to third embodiments. Design changes and additions are permitted without departing from the spirit of the invention according to each claim of the scope.

  In the first to third embodiments, an example of estimating from the vehicle speed V, the yaw rate Y, the lateral acceleration G, and the like as the road surface friction coefficient estimating means has been shown. For example, as described in JP-A-2002-200987, Alternatively, the road surface friction coefficient may be estimated based on parameters such as vehicle speed, turning angle, yaw rate, and the equation of motion of the vehicle.

1 is an overall view showing a steer-by-wire system to which a vehicle steering control device of Embodiment 1 is applied. It is a figure which shows the whole structure of the steering reaction force control system of the vehicle steering control apparatus of Example 1, and a turning angle control system. 1 is a control block diagram of a steer-by-wire system to which an apparatus according to a first embodiment is applied. It is a steering reaction force control system block diagram which shows the motor control command value calculation means of the controller 10 for steering reaction force devices of the first embodiment. It is a turning angle control system block diagram which employ | adopted the robust model matching method in Example 1 apparatus. It is a flowchart which shows the flow of the steering reaction force control process performed in the controller 10 for steering reaction force apparatuses of Example 1 apparatus. It is a figure which shows the whole structure of the steering reaction force control system of the steering control apparatus for vehicles of Example 2, and a turning angle control system. It is a flowchart which shows the flow of the obstacle contact determination control processing performed in the controller 10a for steering reaction force apparatuses of Example 2 apparatus. It is a flowchart which shows the flow of the steering reaction force control process performed in the controller 10a for steering reaction force apparatuses of Example 2 apparatus. It is a flowchart which shows the flow of the turning angle control process performed in the controller 21 for turning apparatuses of Example 2 apparatus. It is a general view which shows the steer-by-wire system to which the vehicle steering control device of the third embodiment is applied. It is a figure which shows the whole structure of the steering reaction force control system of the vehicle steering control apparatus of Example 3, and a turning angle control system. It is a flowchart which shows the flow of the motor overheat protection control process performed with the controller 30 for steering reaction force apparatuses and the controller 34 for steered apparatuses of Example 3. FIG. It is a flowchart which shows the flow of the turning angle control process performed in the controller 34 for turning apparatuses of Example 3 apparatus.

Explanation of symbols

1 Steering wheel (steering means)
2 Steering reaction force actuator 3 Steering reaction force device 4, 5 Steering wheel 6 Steering wheel actuator 7 Steering device 8 Steering column shaft 9 Steering reaction force motor angle sensor (steering angle detection means)
10. Steering reaction force controller (steering reaction force control means)
11 Vehicle speed sensor (vehicle speed detection means)
12 Yaw Rate Sensor 13 Lateral Acceleration Sensor 14 Steering Gear Mechanisms 15 and 16 Operation Conversion Mechanism 17 Steering Motor Angle Sensor 18 Steering Device Controller (steering angle control means)
18a Model matching compensator 18b Robust compensator (disturbance compensator)
18c Differentiator 18d Current limiter 19 Bidirectional communication line

Claims (16)

A steering system having a steering reaction force actuator for generating a reaction force in a steering means and a steering motor for changing a turning angle of a steered wheel ,
The steering system includes: a steering reaction force control unit that calculates a steering reaction force command value for the steering reaction force actuator; and a steering motor that turns a turning angle of a steered wheel to a target turning angle. A turning angle control means for calculating a command current ,
The turning angle control means has a disturbance compensator that calculates a disturbance estimated value based on the command current and the actual motor angle of the steering motor, and compensates the command current,
The steering reaction force control means, the disturbance estimated value and the disturbance equivalent, only disturbance equivalent estimated the steering reaction force command value vehicular steering control apparatus characterized by feedback to. The vehicle steering control device according to claim 1,
The turning angle control means calculates a command current for matching the response of the actual motor angle to the reference model based on the command motor angle and the actual motor angle of the steering motor according to the target turning angle. With a matching compensator,
The disturbance compensator estimates the control inhibition factor including the modeling error of the reference model as a disturbance based on the command current calculated by the model matching compensator and the actual motor angle of the steering motor. A vehicle steering control device, characterized by being a robust compensator for calculating an estimated disturbance value . In the vehicle steering control device according to claim 1 or 2,
Vehicle speed detection means for detecting the vehicle speed;
A steering angle detection means for detecting the steering angle;
The steering reaction force control means has a value obtained by multiplying an actual steering angle by a first gain calculated so as to be a target response and an attenuation coefficient corresponding to the vehicle characteristics, and a target response corresponding to the actual steering angular velocity according to the vehicle characteristics. And the steering reaction force command value is calculated based on a value obtained by adding a limiter process with a predetermined limit value to the sum of the value multiplied by the second gain calculated to be the damping coefficient,
The vehicle steering control device, wherein the first limiter processing unit determines the predetermined limit value according to a vehicle speed and a steering angle . In the vehicle steering control device according to claim 3 ,
A road surface friction coefficient estimating means for estimating the road surface friction coefficient is provided,
The vehicle steering control device, wherein the first limiter processing unit determines the predetermined limit value according to a vehicle speed, a steering angle, and a road surface friction coefficient . In the vehicle steering control device according to claim 3 or 4 ,
The steering reaction force control means is a value calculated by multiplying the difference between the value subjected to the limiter processing by the first limiter processing unit and the target turning angle and the actual turning angle by a third gain corresponding to the vehicle speed. The difference between the target turning angle and the actual turning angle is time-differentiated and the value calculated by multiplying the fourth gain according to the vehicle speed is added, and a disturbance compensator is used. And a second limiter processing unit for calculating a steering reaction force command value by performing a limiter process for limiting the upper limit value to a predetermined value with respect to the value calculated by adding the disturbance equivalent estimated in the above. A vehicle steering control device. The vehicular steering control apparatus as claimed in any one of claims 1 to claim 5,
The steering reaction force control means calculates the target turning angle based on a steering angle, and when the steering angle reaches the maximum steering angle, the steering angle used for calculating the target turning angle is constant at the maximum steering angle. And a steering control device for a vehicle , wherein the steering reaction force is processed to increase in a pulse manner . The vehicle steering control device according to any one of claims 1 to 6,
Obstacle contact determination means for determining whether the steered wheel is in contact with an obstacle based on the absolute value of the difference between the target turning angle and the actual turning angle and the current value of the steering motor. Provided,
The steering reaction force control means performs processing so as to increase the steering reaction force in a pulse manner when it is determined by the obstacle contact determination means that the steered wheel is in contact with the obstacle. A vehicle steering control device. In the vehicle steering control device according to claim 7 ,
The steering control device for a vehicle according to claim 1, wherein the steering reaction force control means switches to normal steering reaction force control when the steered wheel contacts the obstacle and then leaves the obstacle . In the vehicle steering control device according to claim 3 ,
The steering reaction force actuator is a steering reaction force motor,
The steering reaction force control means performs steering reaction force motor current value reduction control for gradually reducing the current value of the steering reaction force motor when the steering reaction force motor is overheated. apparatus. The vehicle steering control device according to claim 9 , wherein
The steering angle control means performs a steering motor current value reduction control for gradually reducing the current value of the steering motor when the steering motor is overheated . The vehicle steering control device according to claim 10,
The steering reaction force control means is provided in an area where the turning angle cannot follow the driver's steering due to the reduction of the current value of the steering motor by the steering motor current value reduction control when the steering motor is overheated. A steering control device for a vehicle, characterized in that the current value of the steering reaction force motor is gradually increased compared to that during normal control . The vehicle steering control device according to claim 9 or 11,
When the steering reaction force motor current value reduction control is canceled, the steering reaction force control means gradually brings the current value of the steering reaction force motor closer to the current value during normal control . Steering control device. The vehicle steering control device according to any one of claims 10 to 12,
The steering angle control means is a vehicle steering control device that immediately returns the current value of the steering motor to the current value during normal control when the steering motor current value reduction control is canceled . The vehicle steering control device according to any one of claims 9 to 13,
The steering reaction force control means sets the switching timing from the normal control to the steering reaction force motor current value reduction control when the turning angle is in the vicinity of the reference position, and also releases the steering reaction force motor current value reduction control release timing. Similarly, the vehicle steering control device is characterized in that it is in the vicinity of the reference position of the turning angle . The vehicle steering control device according to any one of claims 9 to 14 ,
An obstacle avoidance steering detection means for determining the obstacle avoidance steering of the driver based on the steering angle, the steering angular speed, the vehicle speed, and the presence or absence of an obstacle is provided,
When obstacle avoidance steering is performed,
The steered angle control means does not reduce the current value of the steered motor even if the steered motor is overheated.
The vehicle steering control device, wherein the steering reaction force control means does not increase a motor current value . The vehicle steering control device according to any one of claims 9 to 15,
When the steering reaction force motor and the turning motor are both overheated, a warning means for issuing a warning to the driver is provided,
The steering reaction force control means and the turning angle control means perform a steering reaction force motor current value reduction control and a steering motor current value reduction control after a warning is issued by a warning means . Steering control device.

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