JP4595519B2 - Vehicle steering control device and its turning angle control method - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a technical field of a vehicle steering control device used in a steer-by-wire system or the like in which there is no mechanical connection between a steering side having a steering handle and a steered side having steering wheels. Belonging to.

In the conventional steer-by-wire system, based on the deviation between the target turning position and the actual turning position and the turning load, the turning is performed so that the deviation between the target turning position and the actual turning position is zero. The rudder amount was calculated and controlled (for example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 10-310074

  However, in the conventional vehicle steering control device, the followability with respect to the command turning angle from the steering side is high and the steering rigidity is equivalent to infinitely high, and the command turning angle and the actual turning in the steady state are equivalent. The rudder angle always matches. For this reason, it is impossible to accurately simulate the torsion on the steering side and the steering side with respect to a disturbance that causes a load on the steering side. In addition, if the steering stiffness is high, the vehicle tends to oversteer on curved roads, which may increase the slip angle and hinder the running stability of the vehicle. It can also lead to a decrease in comfort.

  The present invention has been made paying attention to the above-mentioned problem, and its object is to accurately simulate the torsion between the steering side and the steered side when traveling with external force applied to the steered wheels. Accordingly, it is an object of the present invention to provide a vehicle steering control device and a turning angle control method thereof that can achieve the stability of vehicle behavior, the improvement of riding comfort and the improvement of steering feeling.

In order to achieve the above object, in the present invention,
A steering actuator that steers steering wheels;
Steering angle detection means for detecting the steering angle of the steering wheel;
Steering control means for outputting a drive command value to the steering actuator so that the steering angle of the steered wheel becomes a command steering angle corresponding to the steering angle;
In a vehicle steering control device comprising:
Transient component estimating means for estimating a transient component amount of disturbance input to the steering wheel;
Stationary component estimation means for estimating a steady component amount of disturbance input to the steering wheel;
A drive command value correcting means for correcting the drive command value based on the before and Symbol transients amount the stationary component amount,
Equipped with a,
The drive command value correcting means is characterized variable and to Rukoto the stationary component correction value is a correction amount of the drive command value based on the constant component amount.

Thus, in the vehicular steering control apparatus of the present invention, a transient component amount and the steady-state component of the disturbance individually estimated, for correcting the dynamic instruction drive according to their response to transients of the disturbance The command turning angle compensation and the command turning angle compensation according to the steady component amount of the disturbance can be controlled independently. Therefore, it is possible to provide a steady deviation given by an external force between the command turning angle and the actual turning angle while compensating for a transient control impediment factor applied in a state where the turning angle changes. As a result, when traveling with external force applied to the steered wheels, it is possible to achieve stability of turning behavior, improvement of riding comfort and improvement of steering feeling.

  Hereinafter, the best mode for carrying out the vehicle steering control device of the present invention will be described based on Examples 1 and 2 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, and FIG. 2 is a steering reaction force control system and turning angle control of the vehicle steering control device of the first embodiment. It is a figure which shows the whole structure of a system.

  A steer-by-wire system to which the vehicle steering control device of the first embodiment is applied includes a steering handle 1 and a steering reaction force actuator (steering reaction force actuator) 2 as shown in FIG. 3, and the steered side by the steered device 7 having the steered wheels 4 and 5 and the steered actuator (steered actuator) 6, there is no mechanical connection.

The steering reaction force device 3 includes a steering handle 1, a steering column shaft 8, and a steering reaction force actuator 2 provided on the steering column shaft 8.
The steering reaction force actuator 2 has a reduction gear mechanism and a motor. The motor has 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. It is attached. The steering reaction force motor angle sensor 9 is used for controlling the angle of the motor and is also used as a steering angle detection means for detecting the actual steering angle θs. In addition, you may provide the sensor which detects the rotation angle of the steering wheel 1 separately.

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

  The steering reaction force controller 10 includes command turning angle calculation means for calculating the command turning angle θta from the actual steering angle θs and the vehicle speed V, control corresponding to the steering input equivalent control value Is, and control corresponding to the turning 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 Isa to which the command value It is added, and the motor control command value Tms to the motor of the steering reaction force actuator 2 Motor drive means by a motor drive circuit that converts the current into a command current.

  The steering device 7 is connected to a steering actuator 6, a steering gear mechanism 12 driven by the steering actuator 6, and a steering rack shaft 13 stroked by the steering gear mechanism 12. Steering wheels 4 and 5.

  The steering actuator 6 has a reduction gear mechanism and a motor, similar to the steering reaction force actuator 2, and the motor serves as a turning motor angle detection means for detecting the rotation speed of the motor shaft. A steering motor angle sensor (actual turning angle detection means and actual turning angular velocity detection means) 15 is provided. The steered motor angle sensor 15 is used for controlling the angle of the motor and is used as a steered angle detecting means for detecting the actual steered angle θt.

As an electronic control means for controlling the steering actuator 6, a steering device controller (steering control means) 16 is provided, and the steering device controller 16 and the steering reaction force device controller 10 are information. Are connected by a bidirectional communication line 17 for exchanging them. The steering device controller 16 includes the vehicle speed sensor 11, a steering motor angle sensor 15 as a steering motor angle detection unit that obtains actual steering angle information, and a front / rear acceleration detection unit as a vehicle longitudinal acceleration detection unit. acceleration Dose capacitors 18, a lateral acceleration sensor 19 as lateral acceleration detecting means of the vehicle, the input information from is supplied.

  The steering device controller 16 corrects the command current with respect to the deviation due to the disturbance between the obstacle turning determination means θ and the instruction turning angle θta and the actual turning angle θt. Correction amount calculation and correction determination means for performing amount calculation and correction determination, and adding a maximum value limit to the value obtained by subtracting the output of the robust compensator from the value obtained by adding the output of the feedforward compensator and the output of the feedback compensator Motor control command value calculating means for calculating a motor control command value by means of motor control means, and motor drive means by a motor drive circuit for converting the motor control command value into a command current Ita to the motor of the steering actuator 6.

FIG. 3 is a block diagram of the steering reaction force control system showing the motor control command value calculation means in the steering reaction force device controller 10 of the first embodiment.
First, the steering reaction force controller 10 includes a calculation unit for a control command value Is corresponding to a steering input, a calculation unit for a control command value Its for a steering output, and a limiter processing unit 10k. ing.

  The steering input equivalent torque Is calculating unit obtains a command value (Ka × θs) by multiplying the actual steering angle θs by a gain Ka corresponding to the vehicle speed V, and a time differential value of the actual steering angle θs. a differentiator 10b for obtaining ωs (= dθs / dt), a gain setting unit 10c for obtaining a command value (Ks × ωs) by multiplying the time differential value ωs of the actual steering angle θs by a gain Ks corresponding to the vehicle speed V, and a command An adder 10d that adds the value (Ka × θs) and the command value (Ks × ωs) to calculate the control command value Is corresponding to the steering input (Is = Ka × θs + Ks × ωs).

  Here, for example, as shown in FIG. 4 (a), the gain Ka is a gain of 1.0 at a vehicle speed with a high steering start frequency, and has a gain of 1.0 or more on the low vehicle speed side and the high vehicle speed side. Given. Further, for example, as shown in FIG. 4 (b), the gain Ks is gain 1.0 at a vehicle speed with a high steering start frequency as in the gain Ka, and is gained at a lower vehicle speed side and a higher vehicle speed side than the vehicle speed. Given by a value greater than 1.0.

The calculation unit for the control command value Its corresponding to the steering output corresponds to a difference unit 10e that calculates a deviation (θta−θt) between the command turning angle θta and the actual turning angle θt, and the vehicle speed to the deviation (θta−θt). Gain setting device 10f that obtains a command value (Kfa × (θta−θt)) by multiplying gain Kfa according to V, and time differential value ωts (= d (θta−θt) / dt) of deviation (θta−θt) A gain differentiator 10g for obtaining the command value (= Kfs × ωts) by multiplying the time differential value ωts by the gain Kfs corresponding to the vehicle speed V, and the command value (Kfa × (θta−θt)) An adder 10i that adds the command value (= Kfs × ωts) to calculate the control command value Its for the steering output equivalent (Its = Kfa × (θta−θt) + Kfs × ωts).
The gain Kfa and the gain Kfs are set according to the vehicle speed V in the same manner as the gains Ka and Ks shown in (a) and (b) of FIG.

  The limiter processing unit 10k adds the steering input equivalent control command value Is and the steering output equivalent control command value Is by the adder 10j to obtain an added value Isa (= Is + Its). A motor control command value Tms is obtained by performing limiter processing with a limit value Ls obtained from the road surface μ estimated from the yaw rate ψ, lateral acceleration YG, and the like.

  Here, as shown in FIG. 4C, the “limit value Ls” is set so as to increase as the road surface μ increases. This prevents the reaction force from becoming too large when the steering angle or the steering angular velocity is increased, prevents the steering handle 1 from being increased or difficult to increase, and depends on the estimated road surface μ. Therefore, it is possible to obtain an optimum steering reaction force.

FIG. 5 is a block diagram of the turning angle control system in the first embodiment. The turning device controller 16 includes a feedforward compensator 16a, a reference model (turning angle estimating means) 16b, a difference unit 16c, Feedback compensator and (stationary component estimated hand stage) 16d, a switch 16e, and adder-subtracter 16f, and a current limiter 16g, and robustness compensator (transients estimating means and the steering angular velocity estimating means) 16h, a gain setting unit 16j , And is configured.

In the switch 16e and the subtracter 16f and the gain setting device 16j, it constitutes drive command value correcting means.

  The feedforward compensator 16a receives the command turning angle θta and outputs a command current feedforward portion Iff that matches a desired response characteristic given in advance to the adder / subtractor 16f. The reference model 16b receives the command turning angle θta, generates a command turning angle reference value θta_ref (turning angle estimated value) through the reference model Gm (s), and outputs the command turning angle to the subtractor 16c.

  The subtractor 16c calculates a deviation by subtracting the actual turning angle θt from the command turning angle reference value θta_ref from the reference model 16b, and outputs the deviation to the feedback compensator 16d. The feedback compensator 16d receives a deviation between the command turning angle reference value θta_ref and the actual turning angle θt, and outputs a command current feedback Ifb corresponding to the deviation to the gain setting device 16j.

The gain setter 16j outputs a value (steady component correction value) Kcs × Ifb obtained by multiplying the command current feedback Ifb by a gain Kcs set in advance according to vehicle characteristics to the switch 16e. The switch 16e is turned on / off according to the vehicle state or the like , thereby switching whether to output the output Kcs × Ifb of the gain setting device 16j to the adder / subtractor 16f.

  The adder / subtractor 16f calculates a command current (drive command value) Ita by subtracting the disturbance compensation output Irbst from the robust compensator 16h from the command current feedforward component Iff from the feedforward compensator 16a. Further, when the switch 16e is ON, the output Kcs × Ifb of the gain setting device 16j is added.

  The current limiter 16g is a current limiter for preventing overcurrent with respect to the motor of the steering actuator 6. When the command current from the adder / subtractor 16f is less than the limit current, the command current is output as the command current Ita to the motor of the steering actuator 6 of the control target Gp (s), and when the current exceeds the limit current, the limit current is output. Is output as a command current Ita to the motor of the steering actuator 6 of the control target Gp (s).

The robust compensator 16h takes in a command current Ita that is an input to the control target Gp (s) and a turning angular velocity ωt that is an output from the control target, and includes a control hindrance including modeling errors (road surface wrinkles, unevenness) For example, input to the steering wheel at the wheel, change in load of the steering wheel during turning, deceleration, etc., torque steer due to torque change of the steering wheel due to change in road surface μ, etc.) Is a disturbance compensator that outputs. The output of the disturbance compensation amount from the robust compensator 16h is used as output I rbST for correcting the command current Ita (drive Doyubi command value) on the steering control in Embodiment 1.

That is, the control system of the steering device controller 16, two-degree-of-freedom control system comprises a robust compensator 16h in addition to the (feedforward compensator 16 a and feedback compensator 16d), the further output stage of the feedback compensator 16d The switch 16e is provided.

  In this control system, the robust compensator 16h is different from the robust compensator of the robust model matching method shown in FIG. 6 in that one of the inputs is not an angle to be controlled (actual turning angle θt) but an angular velocity (steering angular velocity). Since ωt) is used, there is a feature that the stationary one is not compensated, and only the transient one is compensated.

  In addition to this feature, by switching ON / OFF of the switch 16e provided at the output stage of the feedback compensator 16d, by switching whether or not to use the output of this part for control, when turning OFF, the command steering A constant deviation is provided between the angle θta and the actual turning angle θt. When ON, the deviation (N deviation or intended) is caused between the command turning angle θta and the actual turning angle θ. In such a case, it is possible to perform a control such that a correction for eliminating the deviation is performed when a difference from the deviation occurs.

Next, the operation will be described.
[Steering control processing]
FIG. 7 is a flowchart showing the flow of the turning control process executed by the turning device controller 16 according to the first embodiment. Each step will be described below.

In step S1, the vehicle speed V from the vehicle speed sensor 11, the longitudinal acceleration Gar from the longitudinal acceleration sensor 18, the lateral acceleration Gl from the lateral acceleration sensor 19, and the actual steering angle θs from the steering reaction force motor angle sensor 9 are set. The command turning angle θta set in accordance with this, the actual turning angle θt from the turning motor angle sensor 15, the actual turning current It from the turning current detection means provided in the motor drive circuit (not shown), , And the process proceeds to step S2.
Here, the “command steering angle θta” is considered when the gear ratio is variable,
θta = θs × Rst where Rst is determined by the steering / steering gear ratio.

In step S2, following the reading of the input information in step S1, it is determined whether or not the steered wheels 4 and 5 are in contact with an obstacle such as a curb. If YES, the process proceeds to step S3. If NO, To step S4.
Here, the “obstacle” refers to a thing that is difficult to physically increase the turning by touching the steered wheels 4 and 5 such as a curb.
The “obstacle contact determination” includes, for example, that the absolute value of the deviation between the command turning angle θta and the actual turning angle θt is a delay due to communication between the steering side / steering side, a response delay to the command, and a turning angle control. More than the judgment value θa determined in consideration of accuracy, etc., and the time when the actual turning angle θt has not changed compared to the previous value is Tit or more (for example, the maintained state within ± 1 ° is 1 second or more ) And when the actual turning current It is equal to or longer than Itt, it is determined that the steered wheels 4 and 5 are in contact with an obstacle such as a curb (see Japanese Patent Application No. 2003-422289). ).

  In step S3, based on the obstacle contact determination in step S2, the command turning angle θta is set to coincide with the actual turning angle θt, and the process proceeds to return.

In step S4, a correction amount for a deviation due to a disturbance between the command turning angle θta and the actual turning angle θt is calculated, and the process proceeds to step S5.
This correction amount is multiplied by a gain Kcs set in advance according to vehicle characteristics (for example, a high-rigidity sports type has a larger Kcs than a sedan type) to simulate the difference in rigidity due to the vehicle, and according to the vehicle speed V The amount is set to be variable (set smaller as the vehicle speed V is higher).

In step S5, it is determined whether or not the value calculated in step S4 is to be corrected. If YES, the process proceeds to step S6, and if NO, the process proceeds to step S7.
The correction determination is performed according to the longitudinal acceleration Gar, the lateral acceleration Gl, and the driver's steering state read in step S1. For example,
Condition 1: The steady-state deviation calculated by the feedback compensator 16d is a predetermined value or more (for example, a steering angle of 5 ° or more)
Condition 2: Longitudinal acceleration Gar is greater than or equal to the threshold value Gath (Gath is the longitudinal acceleration at which the tire suddenly accelerates to idle)
Condition 3: Longitudinal acceleration Gar is less than or equal to threshold value Grth (Grth is a deceleration that causes rapid deceleration such that the tire locks)
Condition 4: Lateral acceleration Gl is greater than or equal to a threshold Glth (Glth is a lateral acceleration that eliminates the ground contact force of the tire on the turning inner wheel side)
Condition 5: At the time of steering (when the angle of the steering wheel 1 is substantially constant for a predetermined time)
If any one of the above five conditions is satisfied, the correction is not performed, and if all the five conditions are not satisfied, the correction is performed. Thereby, it can correct | amend, ensuring the safety | security of a vehicle.
At the time of steering, the driver is willing to maintain the state, and since the steering is not added, such as turning back and turning back, a constant deviation is given without correction.

  In step S6, since it is determined in step S5 that correction is to be performed, the switch 16e in the output stage of the feedback compensator 16d is turned on, and the process proceeds to return.

  In step S7, since it is determined in step S5 that correction is not performed, the switch 16e in the output stage of the feedback compensator 16d is turned off, and the process proceeds to return.

[Twist between steering / steering]
The equation of motion of the steering system in a current vehicle having a mechanical connection (shaft) between steering / steering can be expressed as follows. FIG. 8 shows a schematic diagram of the steering system, and FIG. 9 shows a schematic diagram of the handle shaft therein.

Equation (1) shows the equation of rotational motion of the steering wheel converted around the kingpin, and equations (2) and (3) show the equation of rotational motion of the steering wheel around the kingpin.
◎ Rotating motion of steering wheel converted around kingpin
Ih (d ² δ / dt ² ) + Ch (dδ / dt) + Ks (α−δ) = Th (1)
◎ Rotating motion of front wheel around kingpin
Ts = (εn + εc) Kf {β + (lf / V) γ−δ} (2)
Is (d ² δ / dt ² ) + Cs (dδ / dt) + Ks (δ−α) = Ts (3)
here,
Ih: Moment of inertia equivalent to the handle around the kingpin
Ch: Coefficient of viscous friction of handle shaft
Ks: kingpin elastic modulus of around [delta]: actual rotation steering angle alpha: angle of rotation in terms of kingpin around the steering wheel
Th: Driver torque
Is: Moment of inertia around the kingpin
Cs: Coefficient of viscous friction around the kingpin
Kf: Cornering power
Ts: Moment acting around the kingpin
If: vehicle center of gravity and front axle distance β: side slip angle εn: pneumatic trail εc: caster rail V: vehicle speed γ: yaw angular velocity.

Equation (2), a steady deviation due to the torsion between the Ts so is to work to the steering wheel as an external force when viewed from the steering system, thereby steering wheel angle and the actual rotation steering angle (3) Will occur. For example, in the formula (1), turn off the steering wheel from [delta] = 0, will be Ks balancing with a torque Th (alpha-[delta]) is generated, the steering wheel angle and the actual rotation steering angle, the deviation occurs and Become. Further, Equation (2), (3), there when the actual rotation steering angle [delta], will be Ks to balance the tire force of the formula (2) ([delta]-alpha) occurs, steering wheel angle and the actual rotation steering angle In this case, a deviation occurs.

[Technical background]
In the conventional steer-by-wire system, as described in JP-A-10-310074, based on the deviation between the target turning position and the actual turning position and the turning load, the target turning position is further increased. The steering amount is calculated and controlled so that the deviation between the actual steering position and the actual steering position becomes zero.

  For this reason, the followability with respect to the command turning angle from the steering side is high, and it is impossible to accurately simulate the torsion on the steering side and the turning side and the steering reaction force to be generated with respect to a disturbance that causes a load on the turning side. . If the torsion on the steering side and the turning side are not simulated, the corresponding disturbance compensation works, so that the actual turning angle is always consistent with the command turning angle. This is equivalent to a vehicle having a very high steering rigidity.

  If the steering rigidity is equivalent to a vehicle with very high steering rigidity like a conventional steer-by-wire system, the actual steering angle is given to the high response when the steering handle is cut slightly larger on a curved road, so the vehicle Prone to oversteer. This is because a driver on a curved road cuts the steering handle slightly larger, and then performs return steering or corrective steering that gradually turns to obtain turning characteristics at the start of turning, and the behavior of the vehicle changes to the curved road. By controlling to be in line with For this reason, on a curved road, the slip angle of the vehicle body increases and the turning behavior stability decreases.

  In addition, if the steering rigidity is equivalent to a vehicle with extremely high steering rigidity on a saddle or swell road, if an external force is applied to the steered wheel, the steered wheel should not be changed so as not to change the actual steered angle. External force is received by the steering actuator. Therefore, when an external force is applied to the steered wheels, the reaction force (shock) received by the steering actuator is transmitted to the vehicle body as it is, so that the riding comfort is reduced.

  In addition, when the steering rigidity is equivalent to a vehicle having a very high steering rigidity, the steering wheel steers without causing a delay in response to the operation of the steering wheel and the yaw rate is generated. Since it becomes unnatural compared with a vehicle equipped with a steering device in which a facing wheel is mechanically connected, the driver feels uncomfortable and the steering feeling is lowered.

  In addition, when a large external force is input to the steered wheels, the steered actuator motor is heavily loaded because a large amount of current flows at once to overcome this and secure the steered wheels. It will be overheated.

[Steering control operation]
On the other hand, in the vehicle steering control apparatus of the first embodiment, the estimated disturbance component compensation is divided into a transient component and a steady component, and further the compensation amount of the steady component is made variable so that the steering actuator By performing control 6, when a disturbance element is input, it is possible to intentionally give a steady deviation between the command turning angle θta and the actual turning angle θt, and steering / steering according to the disturbance. It is possible to simulate the twist between the two and to prevent the driver from feeling uncomfortable.

  In the first embodiment, when the steered wheels 4 and 5 are not in contact with an obstacle such as a curb and the steady deviation obtained by the feedback compensator 16d is equal to or larger than a predetermined value, the steps in the flowchart of FIG. The process proceeds from S1, step S2, step S4, step S5, and step S7. In step S7, the switch 16e is turned off. Therefore, since the steady-state component correction amount of disturbance is set to zero, a steady deviation can be generated between the command turning angle θta and the actual turning angle θt (FIG. 10).

  On the other hand, when the steady-state deviation obtained by the feedback compensator 16d is smaller than the predetermined value, the process proceeds to step S1, step S2, step S4, step S5, step S6 in the flowchart of FIG. The correction amount for the deviation due to is calculated, and in step S6, the switch 16e is turned on. Therefore, since the command current value Ita is corrected according to the disturbance steady-state component correction amount, the control error and the steering feeling caused by the deviation due to the disturbance are suppressed (FIG. 11).

  When the steered wheels 4 and 5 come into contact with an obstacle such as a curb stone, the process proceeds from step S1 to step S2 to step S3 in the flowchart of FIG. 7, and in step S3, the command turning angle θta is set to the actual turning angle. The setting is made to coincide with θt, that is, the deviation between the command turning angle θta and the actual turning angle θt is set to zero.

  In this way, instead of directly changing the command current value of the steered side motor to a certain value, the command steered angle θta on the steered side is determined according to the actual steering angle θs in the normal state. By changing to a place where the deviation between θta and the actual turning angle θt becomes zero, that is, even if the driver turns the steering wheel 1 further, the turning side does not move any more, the current on the turning side is commanded It is not necessary to cancel the deviation between the turning angle θta and the actual turning angle θt, and it is only necessary to cancel the deviation, so that the current can be suppressed, and the motor overheat protection can be achieved. Become.

  In addition, instead of directly changing the command current value of the steered side motor to a certain value, the commanded turning angle θta on the steered side is changed, so it is determined that it is in contact with an obstacle such as a curb The switching when returning from normal control to normal angle control becomes smooth.

[Steering control action]
FIG. 12 is a diagram showing a response of the actual turning angle θt with respect to the command turning angle θta at the time of disturbance input when the switch 16e provided at the output stage of the feedback compensator 16d is turned OFF. When the steady-state deviation obtained by the feedback compensator 16d is greater than or equal to a predetermined value, the disturbance between the command turning angle θta and the actual turning angle θt is prevented by not adding the steady-state component correction amount of the disturbance to the control amount. Therefore, a twist corresponding to a disturbance can be generated between steering / steering.

  FIG. 13 shows the change in the actual turning angle θt when the switch 16e provided at the output stage of the feedback compensator 16d is turned ON and the deviation due to the disturbance between the command turning angle θta and the actual turning angle θt is corrected. FIG. If there is a difference from the N deviation or the intended deviation, the actual turning angle θt can be commanded with good response even if there is a disturbance input by adding the steady component correction amount of the disturbance to the control amount. It is possible to match the angle θta (robust compensation action against disturbance).

  In the first embodiment, the steady component correction amount is set in proportion to the gain Kcs set in advance according to the vehicle characteristics (step S4). Since the gain Kcs is set to a larger value as the vehicle rigidity is higher, the steering wheel 1 and the steered wheels 4 and 5 are different depending on the vehicle type (sport type car, sedan type car, etc.) having different steering rigidity. It is possible to accurately simulate the torsion between the two.

  Further, since the steady component correction amount becomes smaller as the vehicle speed V becomes higher, the vehicle behavior change with respect to the steady component correction of the disturbance becomes larger as the vehicle speed V becomes higher, whereas the steady component correction amount is changed according to the vehicle speed V. By making it small, the influence on the vehicle behavior change according to the vehicle speed V can be suppressed.

  Even when a deviation due to a disturbance occurs between the command turning angle θta and the actual turning angle θt, the steady component correction amount of the disturbance is zero when sudden acceleration / deceleration or excessive skid occurs. (Step S5). That is, when the vehicle behavior change is large, by leaving a deviation due to disturbance, it is possible to suppress the vehicle behavior change accompanying the cancellation of the steady deviation and stabilize the vehicle behavior.

  In addition, when the steering handle 1 is held at a constant angle, the disturbance steady-state component correction amount is set to zero. That is, when the driver does not intend to steer and wants to maintain the current state, leaving the steady deviation of the disturbance can prevent the driver from feeling uncomfortable.

Next, the effect will be described.
In the vehicle steering control apparatus according to the first embodiment, the following effects can be obtained.

(1) A steering actuator 6 that steers the steered wheels 4 and 5, a steering reaction force motor angle sensor 9 that detects the steering angle of the steering handle 1, and a steering reaction force that detects the actual steering angle θs. a motor angle sensor 9, to set the command steering angle θta so that the turning angle corresponding to the actual steering angle [theta] s, and outputs the drive Doyubi command value obtaining command steering angle θta to steering actuator 6 In a vehicle steering control device including a steering device controller 16, the transient component amount and the steady component amount of disturbance input to the steered wheels 4 and 5 are estimated, respectively, and the transient component amount and the steady component amount are estimated. The drive command value is corrected based on the steady component correction value corresponding to. Therefore, it is possible to provide a steady deviation given by an external force between the command turning angle θta and the actual turning angle θt while compensating for a transient control impediment factor applied in a state where the turning angle changes. it can. As a result, when traveling with an external force applied to the steered wheels 4, 5, it is possible to achieve stability of turning behavior, improved ride comfort, and improved steering feeling. Further, since a special sensor is not required when giving a steady deviation between the command turning angle θta and the actual turning angle θt, the cost can be reduced accordingly. Further, when a steady deviation is provided between the command turning angle θta and the actual turning angle θ, the command current to the motor of the steering actuator 6 is compared with a case where no deviation is provided. Since Ita is suppressed, the motor can be prevented from being overheated.

(2) robust to output a feedforward compensator 16a for outputting a command current feedforward amount Iff from command steering angle [theta] ta, the Irbst a transient formation amount of disturbance from the difference between the actual turning angular velocity ωt and the command current Ita A compensator 16h, a feedback compensator 16d for outputting a command current feedback Ifb from a difference between a command turning angle reference value θta_ref which is a reference model output of the command turning angle θta and an actual turning angle θt, and a command current feedback A gain setting unit 16j that multiplies the minute Ifb by a gain Kcs corresponding to the rigidity of the vehicle to calculate a steady component correction value Kcs × Ifb of the disturbance, and an output stage of the gain setting unit 16j. / includes a switch 16e for OFF, command current feedforward amount Iff, disturbances of the transient formation amount Irbst, a subtracter 16f for outputting a command current Ita from the stationary component compensation value Kcs × Ifb disturbance, the Therefore, the compensation amount of the steady component can be varied with a simple configuration.

(3) A robust compensator 16h that estimates a steered angular velocity estimated value from the command current Ita and a steered motor angle sensor 15 that detects the actual steered angular velocity ωt of the steered wheels 4 and 5 are provided. Since the compensator 16h estimates the amount of the transient component of the disturbance from the deviation between the steered angular velocity estimated value and the actual steered angular velocity ωt, the transient component of the disturbance can be estimated without using a special sensor. Further, even when an error occurs in the parameter due to the modeling error of the control object Gp (s), the response of the turning control can be brought close to the response of the reference model 16b by compensating for the transient component.

  (4) A reference model 16b that estimates the command turning angle reference value θta_ref from the command turning angle θta, and a steering motor angle sensor 15 that detects the actual turning angle θt of the steered wheels 4 and 5 The feedback compensator 16d estimates the steady-state component of the disturbance from the deviation between the command turning angle reference value θta_ref and the actual turning angle θt, and therefore can estimate the steady-state component of the disturbance without using a special sensor.

(5) The drive command value correction means increases the steady-state component correction value as the vehicle rigidity increases, so that the steering handle 1 and the steering handle 1 are different depending on the vehicle type (sport type vehicle, sedan type vehicle, etc.) with different steering stiffness. The torsion between the steering wheels 4 and 5 can be accurately simulated.

(6) the drive command value correcting means, the higher the vehicle speed V, for small Ku the stationary component correction value, it is possible to suppress the vehicle behavior change caused by the steady-state error eliminated, thereby stabilizing the vehicle behavior in accordance with the vehicle speed V Can do.

(7) The drive command value correction means turns off the switch 16e during the steering operation and sets the steady component correction value to zero. Therefore, when the driver desires the current steering state, the disturbance steady component By not performing the correction, it is possible to prevent the driver from feeling uncomfortable.

(8) Vehicle behavior state quantity detection means (longitudinal acceleration sensor 18 and lateral acceleration sensor 19) for detecting the longitudinal acceleration Gar or lateral acceleration Gl of the vehicle as the vehicle behavior state quantity is provided, and the drive command value correction means includes the vehicle behavior state when the magnitude of the amount (longitudinal acceleration Gar or lateral acceleration Gl) is a predetermined value or more, and OFF the switch 16e, to the stationary component correction amount to zero to suppress the vehicle behavior change caused by the steady-state deviation eliminated, vehicle behavior Can be stabilized.

(9) The drive command value correction means sets the steady component correction value to zero when the steady component amount is equal to or greater than a predetermined value. Therefore, it is possible to suppress overheating of the motor.

(10) Steering reaction force actuator 2 that applies reaction force to the steering handle 1, steering motor angle sensor 15 that detects the actual steering angle θt of the steered wheels 4 and 5, and the steering device controller And a steering reaction force device controller 10 for outputting a steering reaction force command value corresponding to a deviation between the command turning angle θta and the actual turning angle θt from the steering reaction force actuator 2 to the steering reaction force device 2. When a deviation occurs between the command turning angle θta and the actual turning angle θt, it is possible to notify that the steering tires 4 and 5 have an input of external force due to a change in the steering reaction force.

First, the configuration will be described.
FIG. 14 is a block diagram of the turning angle control system in the second embodiment. In contrast to the configuration of the first embodiment shown in FIG. 5, a disturbance compensation output limiter 16k is provided at the output stage of the feedback compensator 16d instead of the switch 16e. It differs in the point provided. In the second embodiment, a drive command value correcting unit is configured by the gain setting unit 16j, the disturbance compensation output limiter 16k, and the adder / subtractor 16f.

The disturbance compensation output limiter 16k the deviation between the instruction turning angle θta and actual rolling steering angle θt is set limiter value Lfb more increases to a large value (Fig. 15). That is, when the deviation is large, the limiter value Lfb is set to a large value and the restriction on the command current feedback Ifb is made small so that the deviation is quickly eliminated. On the other hand, when the deviation is small, the limiter value Lfb is set to a small value, and the restriction on the command current feedback Ifb is increased, so that the feedback is gently acted on the deviation.

Further, the limiter value Lfb varies according to parameters such as vehicle characteristics, vehicle state, and steering state.
(a) The higher the vehicle rigidity, the higher the limiter value Lfb.
(b) The higher the vehicle speed V, the lower the limiter value Lfb.
(c) The limiter value Lfb is set lower as the longitudinal acceleration Gar is higher.
(d) The higher the lateral acceleration Gl, the lower the limiter value Lfb.
(e) The limiter value Lfb is set lower as the steering angular velocity is higher.

Next, the operation will be described.
[Steering control processing]
FIG. 16 is a flowchart showing the flow of the turning control process executed by the turning device controller 16 according to the second embodiment. Each step will be described below. In addition, the same step number is attached | subjected to the step which performs the same process as the steering control process of Example 1 shown in FIG. 7, and description is abbreviate | omitted.

  In step S22, since it is determined that correction is performed in step S5, the value Lfb of the disturbance compensation output limiter 16j in the output stage of the feedback compensator 16d is changed to the vehicle stiffness, vehicle speed V, longitudinal acceleration, lateral acceleration, and steering angular velocity. Set accordingly and move to return.

  In step S23, since it is determined in step S5 that correction is not performed, the value Lfb of the disturbance compensation output limiter 16j in the output stage of the feedback compensator 16d is changed to Lfb = 0, and the process proceeds to return.

As described in the first embodiment, when the steady deviation obtained by the feedback compensator 16d is smaller than the predetermined value, the command current value Ita is corrected according to the steady component correction value of the disturbance. It is possible to suppress the control error and the steering feeling caused by the deviation due to the disturbance. When the steady deviation obtained by the feedback compensator 16d is equal to or larger than a predetermined value, the steady component correction value of the disturbance is set to zero, so that the steady deviation is between the command turning angle θta and the actual turning angle θt. Deviation can be generated.

Further, the limiter value Lfb as deviation between the instruction turning angle θta and actual rolling steering angle θt is increased is set to a large value, depending the stationary component correction value on the deviation between instruction turning angle θta and actual steered angle θt Limit to the upper limit. Therefore, when the steady deviation obtained by the feedback compensator 16d is smaller than a predetermined value, the control responsiveness can be changed according to the deviation between the command turning angle θta and the actual turning angle θt.

[Limiter value variable action according to vehicle characteristics, vehicle conditions, etc.]
In the second embodiment, the higher the vehicle rigidity is, the higher the limiter value Lfb of the disturbance compensation output limiter 16k is set. Therefore, the higher the vehicle rigidity is, the smaller the restriction on the steady component correction value is reduced. The higher the control response, the higher the control response.

Further, the higher the vehicle speed V, the longitudinal acceleration Gar, and the lateral acceleration Gl, the lower the limit value Lfb of the disturbance compensation output limiter 16k, and the larger the limit amount of the steady component correction value , the higher the speed range, the sudden acceleration / deceleration, When the vehicle behavior change is large, such as when turning suddenly, the influence on the vehicle behavior can be suppressed by gently applying feedback to the deviation.

Next, the effect will be described.
In the vehicle steering control device of the second embodiment, the following effects are obtained in addition to the effects (1) to (10) of the first embodiment.

(11) provided with a steering motor angle sensor 15 for detecting the actual steered angle θt of the steering wheel 4 and 5, the drive command value correcting means, the deviation between the instruction turning angle θta and actual rolling steering angle θt The limiter value Lfb is set to a larger value as the value becomes larger, and the steady component correction value is limited to an upper limit value corresponding to the deviation between the command turning angle θta and the actual turning angle θt. Therefore, when the deviation is large, the deviation can be quickly reduced, and when the deviation is small, the deviation can be slowly reduced.

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

For example, the steady component estimating means for estimating the steady component amount of the disturbance is not limited to the feedback compensator. For example, a disturbance compensator for estimating a disturbance from the command current Ita and the actual turning angle θt may be provided, and the steady component amount may be obtained by passing the output of the disturbance compensator through a low-pass filter.

  In the first and second embodiments, the vehicle steering control device applied to the steer-by-wire system in which the steering side and the steered side are completely separated from each other is shown. Even if mechanically connected as a countermeasure against failure, the steering reaction force is not transmitted to the steering wheel under normal conditions, or the ratio between the steering angle and the turning angle is not affected even if the steering side and the turning side are mechanically connected. This is a control system that makes the steering gear ratio variable.The steering actuator that steers the steered wheels and the command turning angle are set so that the steering angle is in accordance with the steering angle. The present invention can be applied to any vehicle including steering control means for outputting the obtained driving force command value to the steering actuator.

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. FIG. 2 is a steering reaction force control system block diagram showing motor control command value calculation means of the steering reaction force device controller in the first embodiment. It is a figure which shows the example of a setting according to the vehicle speed V of each gain Ka and Ks in steering reaction force control, and the example of a setting according to the estimated road surface micro | micron | mu of limit value Ls. 1 is a block diagram of a turning angle control system in Embodiment 1. FIG. It is a turning angle control system block diagram using the conventional robust model matching method. It is a flowchart which shows the flow of the steering control process performed in the controller 16 for steering apparatuses of Example 1. FIG. It is the schematic of the steering system with a mechanical connection between steering / steering. It is the schematic of the handle shaft in the steering system with a mechanical connection between steering / steering. It is a figure which shows the response of the actual turning angle (theta) t with respect to the instruction | command turning angle (theta) ta when not providing disturbance compensation when there exists an error in the parameter of control object. It is a figure which shows the response of the actual turning angle (theta) t with respect to instruction | command turning angle (theta) ta when disturbance compensation is put when there exists an error in the parameter of control object. It is a figure which shows the response of the actual turning angle (theta) t with respect to instruction | command turning angle (theta) ta when a disturbance is added when the part for feedback is not made to work. It is a figure which shows the response of the actual turning angle (theta) t with respect to the instruction | command turning angle (theta) ta at the time of deviation correction by disturbance. 6 is a block diagram of a turning angle control system in Embodiment 2. FIG. It is a setting map of the limiter value Ifb. It is a flowchart which shows the flow of the steering control process performed in the controller 16 for steering apparatuses of Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steering handle 2 Steering reaction force actuator 3 Steering reaction force device 4, 5 Steering wheel 6 Steering actuator 7 Steering device 8 Steering column shaft 9 Steering reaction force motor angle sensor 10 Steering reaction force device controller 11 Vehicle speed Sensor 12 Steering gear mechanism 13 Steering rack shaft 15 Steering motor angle sensor 16 Steering device controller 16a Feed forward compensator 16b Reference model 16c Differencer 16d Feedback compensator 16e Switch 16f Adder / Subtractor 16g Current limiter 16h Robust compensator 16j Gain setting device 16k Disturbance compensation output limiter 17 Bidirectional communication line 18 Longitudinal acceleration sensor 19 Lateral acceleration sensor

Claims (11)

A steering actuator that steers steering wheels;
Steering angle detection means for detecting the steering angle of the steering wheel;
Steering control means for outputting a drive command value to the steering actuator so that the steering angle of the steered wheel becomes a command steering angle corresponding to the steering angle;
In a vehicle steering control device comprising:
Transient component estimating means for estimating a transient component amount of disturbance input to the steering wheel;
Stationary component estimation means for estimating a steady component amount of disturbance input to the steering wheel;
Drive command value correcting means for correcting the drive command value based on the transient component amount and the steady component amount;
With
The vehicle steering control device, wherein the drive command value correcting means makes a steady component correction value that is a correction amount of the drive command value based on the steady component amount variable. The vehicle steering control device according to claim 1,
Steering angular velocity estimation means for estimating a steering angular velocity estimation value from the drive command value;
An actual turning angular velocity detecting means for detecting an actual turning angular velocity of the steered wheel;
With
The vehicle steering control device, wherein the transient component estimation means estimates the transient component amount from a deviation between the steered angular velocity estimated value and the actual steered angular velocity. The vehicle steering control device according to claim 1 or 2,
A turning angle estimating means for estimating a turning angle estimated value from the command turning angle;
An actual turning angle detection means for detecting an actual turning angle of the steering wheel;
With
The vehicle steering control device, wherein the steady component estimating means estimates the steady component amount from a deviation between the steered angle estimated value and the actual steered angle. The vehicle steering control device according to any one of claims 1 to 3,
The vehicle steering control device characterized in that the drive command value correction means increases the steady component correction value as the rigidity of the vehicle increases. The vehicle steering control device according to any one of claims 1 to 4,
The vehicle steering control device, wherein the drive command value correction means decreases the steady component correction value as the vehicle speed increases. The vehicle steering control device according to any one of claims 1 to 5,
The vehicle steering control device, wherein the drive command value correction means sets the steady component correction value to zero during steering. The vehicle steering control device according to any one of claims 1 to 6,
Vehicle behavior state quantity detecting means for detecting the longitudinal acceleration or lateral acceleration of the vehicle as the vehicle behavior state quantity,
The vehicle steering control device, wherein the drive command value correction means sets the steady component correction value to zero when the longitudinal acceleration or the lateral acceleration is greater than or equal to a predetermined value. The vehicle steering control device according to any one of claims 1 to 7,
The drive command value correction means sets the steady component correction value to zero when the steady component amount is equal to or greater than a predetermined value. The vehicle steering control device according to any one of claims 1 to 8,
An actual turning angle detection means for detecting an actual turning angle of the steered wheel;
The drive command value correcting means limits the steady component correction value to an upper limit value corresponding to a deviation between the command turning angle and the actual turning angle. The vehicle steering control device according to any one of claims 1 to 9,
A steering reaction force actuator that applies a reaction force to the steering wheel;
An actual turning angle detection means for detecting an actual turning angle of the steering wheel;
A steering reaction force control means for outputting a steering reaction force command value corresponding to a deviation between the command turning angle and the actual turning angle to the steering reaction force actuator;
A vehicle steering control device comprising: A steering actuator that steers steering wheels;
Steering angle detection means for detecting the steering angle of the steering wheel;
Steering control means for outputting a drive command value to the steering actuator so that the steering angle of the steered wheel becomes a command steering angle corresponding to the steering angle;
In a vehicle steering control device comprising:
A transient component amount and a steady component amount of disturbance input to the steered wheel are respectively estimated, the drive command value is corrected by the transient component amount and the steady component amount, and the based on the steady component amount A turning angle control method for a vehicle steering control device, wherein a steady component correction value that is a correction amount of a drive command value is variable.

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