JP2016104632A - Steering reaction force control device for steer-by-wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering reaction force control device for a steer-by-wire having stable steering reaction force for achieving comfort steering feeling on the basis of a behavior state of a vehicle and a road surface state without being affected by high frequency components included in an acquisition value of a sensor or the like to be used for generating the steering reaction force.SOLUTION: In a steering reaction force control device for a steer-by-wire, steering control means 16 includes: turning reaction force or the like estimation means 17 for calculating an estimation value of turning reaction force or the like from a vehicle motion model 20; and comparison means 18 for comparing the estimation value calculated in the turning reaction force or the like estimation means 17 with a detection value detected from a turning reaction force sensor 8 and selecting either the estimation value or the detection value; and steering reaction force generation means 19 which uses the selected estimation value or detection value for generation of steering reaction force. The comparison means 18 selects the estimation value calculated from the vehicle motion model 20 if vehicle speed is a fixed value or more, and selects the detection value detected from the turning reaction force sensor 8 if the vehicle speed is less than the fixed value.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a steering reaction force control device for a steer-by-wire type steering device that is steered by a steering wheel that is not mechanically connected to a shaft between tie rods for steering.

Conventionally, a steer-by-wire type steering apparatus has been proposed in which steering is performed with a steering wheel that is not mechanically connected to the shaft between tie rods. In this steer-by-wire type steering device, with respect to a method of generating a steering reaction force applied to the steering wheel, a technique (Patent Document 1) that detects a turning reaction force acting on a turning mechanism with a turning reaction force sensor, or a steering angle, In addition to steering angular velocity and steering angular acceleration, a technique (Patent Document 2) is disclosed that generates a steering reaction force using acquired values (yaw rate, lateral acceleration, steering reaction force) indicating a vehicle behavior state. .
Further, in a steering device such as EPS having a mechanical connection between a steering unit including a steering wheel and a steering mechanism unit that changes the direction of the tire, an assist torque to be applied to the steering torque by the steering wheel turning operation is calculated. In some cases, the steering feeling is changed using a vehicle motion model (Patent Document 3).

Japanese Patent Laid-Open No. 10-258748 JP 2000-108914 A JP 2004-338616 A

  In a conventional steering apparatus such as EPS, the frictional force in each mechanism part is directly felt as a steering reaction force. On the other hand, in steer-by-wire, since there is no mechanical connection between the steering unit and the steering mechanism unit, a steering reaction force is generated by a steering reaction force actuator provided in the steering unit. For the generation of the steering reaction force, the reaction force is generated based on the value of the steering reaction force sensor provided in the steering mechanism, and the behavior state of the vehicle is determined in addition to the steering angle, the steering angular velocity, and the steering angular acceleration. There is known a method for generating a reaction force by using acquired values (yaw rate, lateral acceleration, turning axial force, etc.). However, the acquired values of the sensors used to generate these reaction forces include high-frequency components due to the influence of vibrations due to road surface unevenness and individual differences in the alignment of the left and right wheels, leading to a deterioration in steering feeling.

In Patent Document 1, a high-frequency component is attenuated by passing a low-pass filter through the acquired steering reaction force sensor signal, but a time delay occurs by passing the low-pass filter, and the control system becomes unstable. The potential is great.
In Patent Document 2, since the acquired value indicating the behavior state of the vehicle is used as it is, it is considered that the steering feeling deteriorates depending on the situation due to the influence of the high frequency component.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a stable steering feeling that is not affected by high-frequency components contained in an acquired value of a sensor or the like used for generating a steering reaction force and that provides a comfortable steering feeling based on a vehicle behavior state and a road surface state. A steering reaction force control device for a steer-by-wire steering reaction force.

A steer-by-wire steering reaction force control apparatus according to a first aspect of the present invention includes a steering angle sensor 14 for detecting a steering angle with respect to a steering wheel 1 that is not mechanically connected to a steering tie-rod shaft 6. Based on the steering reaction force motor 13 that gives a steering reaction force and the steering angle detected by the steering angle sensor 14, the turning angle of the steering angle is adjusted together with driving state detection signals from other sensors 11 mounted on the vehicle. A steering reaction force control device in a steer-by-wire type steering device having a steering control means 16 that generates a command signal and controls a steering motor 15 of a steering mechanism 7 that drives a shaft 6 between tie rods,
The steering control means 16
Steering reaction force etc. estimating means 17 for calculating an estimated value of a steering reaction force or a parameter representing vehicle behavior from the vehicle motion model 20;
The estimated value calculated by the steered reaction force estimating means 17 is compared with the detected value detected from the steered reaction force sensor 8 for detecting the steered reaction force acting on the steered mechanism 7. Comparing means 18 for selecting one of the estimated value and the detected value in accordance with a given condition;
Steering reaction force generation means 19 that uses the estimated value or the detection value selected by the comparison means 18 to generate a steering reaction force,
The comparing means 18 selects the estimated value calculated from the vehicle motion model 20 if the vehicle speed is equal to or higher than a predetermined value as the predetermined condition, and the vehicle speed is less than the predetermined value. If there is, the detected value detected from the steering reaction force sensor 8 is selected.

  According to this configuration, the steering angle sensor 14 detects the steering angle, and the sensor for detecting the turning reaction force, that is, the turning reaction force sensor 8 detects the turning reaction force acting on the turning mechanism 7. Other sensors 11 detect the driving state. The steering control means 16 generates a turning angle command signal together with the driving state detection signal based on the steering angle, and controls the turning motor 15. The steering reaction force estimation means 17 in the steering control means 16 calculates an estimated value of the steering reaction force from the vehicle motion model 20 based on the vehicle motion equation. For example, if the vehicle speed is greater than a certain value, the estimated value of the steering reaction force calculated from the vehicle motion model 20 is used. If the vehicle speed is less than a certain value, the turning reaction force detected by the turning reaction force sensor 8 is used.

  The comparison means 18 in the steering control means 16 compares the estimated value of the calculated turning reaction force with the detected value detected from the turning reaction force sensor 8, and according to a predetermined condition, the estimated value and the detected value. Select one of the values. As the “predetermined condition”, for example, when the vehicle speed is equal to or greater than a predetermined value, if the difference between the estimated value and the detected value is equal to or less than a threshold value Fs, an estimated value from the vehicle motion model 20 is employed. To obtain the steering reaction force term. In normal steering, the “threshold value Fs” is set so as to allow the estimation error so that the estimated value is adopted. Thus, when the estimated value from the vehicle motion model 20 is employed when the vehicle speed is equal to or higher than the predetermined value, a high-frequency component due to the influence of vibration is not included.

  When the difference between the estimated value and the detected value is larger than the threshold value, the turning reaction force detected by the turning reaction force sensor 8 is used. For example, the steering reaction force that is an actual measurement value detected by the steering reaction force sensor 8 is used only in an abnormal situation where the estimated value is clearly significantly different from the detection value. When the turning reaction force is used when the vehicle speed is less than a certain value, or when the estimated value is significantly different from the detected value as described above, the value obtained from the turning reaction force sensor 8 is, for example, A high-frequency component included in the signal is attenuated through a low-pass filter, and a steered reaction force term is calculated. By the way, when the vehicle speed is less than a predetermined value, such as when the steering wheel 1 is stationary, the stationary operation is a slow operation of, for example, 0.5 Hz or less, so that the time delay due to the low-pass filter does not matter.

  The steering reaction force generation means 19 uses the estimated value or the detection value selected by the comparison means 18 as a turning reaction force term for generating a steering reaction force. The steering reaction force is generated using the steering reaction force term, for example, using a spring element proportional to the steering angle, a viscous element proportional to the steering angular velocity, an inertia element proportional to the steering angular acceleration, and a friction element. ing. Since the steering angle, the steering angular velocity, and the steering angular acceleration can be acquired by the steering angle sensor 14 in the vicinity of the steering wheel, high-frequency components due to unsprung vibrations are not included. Therefore, a stable steering reaction force that is not affected by the high-frequency component included in the acquired value of the sensor or the like used for generating the steering reaction force and that realizes a comfortable steering feeling based on the behavior state and road surface state of the vehicle. This steer-by-wire steering device can be realized.

A steer-by-wire steering reaction force control apparatus according to a second aspect of the present invention includes a steering angle sensor 14 for detecting a steering angle with respect to a steering wheel 1 that is not mechanically connected to a steering tie-rod shaft 6. Based on the steering reaction force motor 13 that gives a steering reaction force and the steering angle detected by the steering angle sensor 14, the turning angle of the steering angle is adjusted together with driving state detection signals from other sensors 11 mounted on the vehicle. A steering reaction force control device in a steer-by-wire type steering device having a steering control means 16 that generates a command signal and controls a steering motor 15 of a steering mechanism 7 that drives a shaft 6 between tie rods,
The steering control means 16
Steering reaction force estimation means 17 for calculating an estimated value of a steering reaction force or a parameter representing vehicle behavior from the vehicle motion model 20;
The estimated value calculated by the steered reaction force estimating means 17 is compared with the detected value detected from the steered reaction force sensor 8 for detecting the steered reaction force acting on the steered mechanism 7. Comparing means 18 for selecting one of the estimated value and the detected value in accordance with a given condition;
Steering reaction force generation means 19 that uses the estimated value or the detection value selected by the comparison means 18 to generate a steering reaction force,
If the difference between the estimated value and the detected value is greater than a threshold value when the vehicle speed is equal to or greater than a predetermined value, the comparing means 18 detects the steering reaction force sensor 8 as the predetermined condition. The detection value is selected.
If the difference between the estimated value and the detected value is less than or equal to a threshold value when the vehicle speed is equal to or higher than a predetermined value, the comparing means 18 determines the estimated value from the vehicle motion model 20 as the predetermined condition. When the vehicle speed and the difference condition are not satisfied, the detected value may be selected. The predetermined value is appropriately determined by simulation, experiment, or the like.
The steering reaction force sensor 8 may be provided on the tie rod shaft 6 or the tie rod 5. According to this configuration, the steer-by-wire steering device can be brought close to the feeling of the EPS mechanically connected to the shaft between the tie rods.

  The steering reaction force generation means 19 estimates one of yaw rate, roll rate, yaw angle, roll angle, and lateral acceleration as a parameter representing vehicle behavior from the vehicle motion model 20 and uses it as the estimated value. Also good. The vehicle behavior term is obtained by multiplying a coefficient corresponding to each parameter indicating the vehicle behavior. In this case, it is possible to output the vehicle behavior that could not be obtained with the conventional steer-by-wire type steering device by reflecting it in the steering reaction force, and the steering device according to the preference of the operator, the type of vehicle, etc. Can be realized.

  The steering reaction force generating means 19 uses any one of a spring component proportional to the steering angle, a viscosity component proportional to the steering angular velocity, an inertia component proportional to the steering angular acceleration, and a friction component for generating the steering reaction force. It is also good. In this case, it is possible to prevent a sense of incongruity and vibration when operating the steering wheel, and it is possible to obtain the same response as a conventional steering apparatus such as EPS.

  The steering reaction force generating means 19 may change the steering reaction force according to the vehicle speed. For example, by changing the steering reaction force in the high speed range to be larger than the steering reaction force in the medium / low speed range, a more stable steering reaction force can be obtained in the high speed range, and operation can be performed with a small force in the medium / low speed range. It is possible to obtain a steering reaction force that is easy to do.

A steer-by-wire steering reaction force control apparatus according to a first aspect of the present invention includes a steering angle sensor that detects a steering angle with respect to a steering wheel that is not mechanically connected to a shaft between tie rods for steering, and a steering reaction force. Based on the steering reaction force motor that applies force and the steering angle detected by the steering angle sensor, the steering angle command signal is generated together with the driving state detection signal from other sensors mounted on the vehicle, It is a steering reaction force control device in a steer-by-wire type steering device having steering control means for controlling a steering motor of a steering mechanism that drives a shaft between tie rods. The steering control means includes a steering reaction force estimation means for calculating an estimated value of a steering reaction force or a vehicle behavior parameter from the vehicle motion model, and the estimation calculated by the steering reaction force estimation means. And a detected value detected from a turning reaction force sensor that detects a turning reaction force acting on the turning mechanism, and according to a predetermined condition, either one of the estimated value or the detected value is compared. Comparing means for selecting, and steering reaction force generating means for using the estimated value or the detected value selected by the comparing means for generating a steering reaction force (premise configuration). The comparing means selects the estimated value calculated from the vehicle motion model if the vehicle speed is not less than a predetermined value as the predetermined condition, and if the vehicle speed is less than the predetermined value, The detection value detected from the steering reaction force sensor is selected. For this reason, stable steering reaction that is not affected by high-frequency components contained in the acquired value of the sensor or the like used for generating the steering reaction force and that realizes a comfortable steering feeling based on the behavior state and road surface state of the vehicle. A force steer-by-wire can be obtained.
In a steer-by-wire steering reaction force control apparatus according to a second aspect of the present invention, in the premise configuration, the comparing means is configured to calculate the estimated value when the vehicle speed is equal to or higher than a predetermined value as the predetermined condition. If the difference between the detection values is larger than a threshold value, the detection value detected from the steering reaction force sensor is selected. In addition, it is possible to obtain a steer-by-wire with a stable steering reaction force that realizes a comfortable steering feeling based on the behavior state of the vehicle and the road surface state.

It is explanatory drawing which shows schematic structure of the steer-by-wire type steering apparatus provided with the steering reaction force control apparatus which concerns on 1st Embodiment of this invention, and the conceptual structure of the control system. It is a block diagram of a control system of the steering reaction force control device. It is a flowchart of a process of the steering control means in the steering reaction force control device. It is a figure which shows the relationship between a steering angle and a spring component in the steering reaction force control apparatus which concerns on other embodiment of this invention. It is a figure which shows the relationship between steering reaction force and a friction component in the steering reaction force control apparatus which concerns on further another embodiment of this invention. It is a figure which shows the relationship between the vehicle speed and a steering reaction force coefficient in the steering reaction force control apparatus which concerns on further another embodiment of this invention. It is a flowchart of the process of a steering control means in the steering reaction force control apparatus which concerns on further another embodiment of this invention.

A first embodiment of the present invention will be described with reference to FIGS. The following description also includes a description of a steer-by-wire steering reaction force control method.
FIG. 1 is an explanatory diagram showing a schematic configuration of a steer-by-wire type steering device including a steering reaction force control device according to this embodiment and a conceptual configuration of its control system. As shown in FIG. 1, the steer-by-wire type steering device includes a steering wheel 1, a steering mechanism 2, and a steering tie rod connected to left and right steering wheels 3 and 3 via a knuckle arm 4 and a tie rod 5. An intermediate shaft 6, a turning mechanism 7, a turning reaction force sensor 8, other sensors 11 such as a vehicle speed sensor 9 and an acceleration sensor 10, and an ECU (electric control unit) 12 as a steering reaction force control device; Is provided. The ECU 12 includes steering control means described later, and is constituted by a microcomputer and an electronic circuit including a control program thereof.

The steering mechanism 2 includes a steering reaction force motor 13 that applies a steering reaction force to the steering wheel 1 that is not mechanically connected to the steering tie rod shaft 6, and a steering that detects the steering angle of the steering wheel 1. And an angle sensor 14.
The steered mechanism 7 includes a steered motor 15 that drives the shaft 6 between the tie rods. The steered motor 15 transmits the rotation as an axial movement to the tie rod shaft 6. The turning reaction force sensor 8 is a sensor that detects a turning reaction force that acts on the turning mechanism 7. For example, a load cell, a load sensor, or the like is applied to the turning reaction force sensor 8. In this case, when the steering motor 15 is rotated, the tie rod 5 moves in the axial direction, so that the steering reaction force sensor 8 detects the axial force applied to the tie rod 5 as the displacement of the load support portion. Converted into an electrical signal. In this example, the steering reaction force sensors 8 and 8 are provided on the tie rods 5 and 5, respectively, but the steering reaction force sensor 8 may be provided only on one tie rod 5. It is also possible to provide a steering reaction force sensor 8 on the shaft 6 between the tie rods.

  FIG. 2 is a block diagram of a control system of the steering reaction force control device. As shown in FIG. 2, the steering control unit 16 of the ECU 12 includes a steering reaction force estimation unit 17, a comparison unit 18, and a steering reaction force generation unit 19. The steering reaction force estimation means 17 calculates an estimated value of the steering reaction force from the vehicle motion model 20 based on the vehicle motion equation. The comparison means 18 compares the estimated value of the turning reaction force calculated by the turning reaction force estimation means 17 with the detected value detected from the turning reaction force sensor 8, and according to a predetermined condition, Either the estimated value or the detected value is selected. The steering reaction force generation means 19 uses the estimated value or the detection value selected by the comparison means 18 for generating the steering reaction force.

The vehicle motion model 20 was constructed with the following assumptions. When the vehicle traveling direction is the X-axis direction, the vehicle width direction is the Y-axis direction, and the vertical direction of the vehicle is the Z-axis direction,
A three-degree-of-freedom model describing the motion around the Y-axis direction, the Z-axis (yaw), and the X-axis (roll).
・ To take into account the difference in lateral force acting on the left and right wheels, a four-wheel model will be adopted.
・ Tire lateral force matches the Y-axis direction.
-The vehicle moves at a constant speed V in the X-axis direction (straight).

  The comparison means 18 compares the estimated value of the turning reaction force calculated from the vehicle motion model as described above with the actual turning reaction force, which is the detected value acquired by the turning reaction force sensor 8, and If the difference is equal to or less than the threshold value Fs, an estimated value from the vehicle motion model 20 is adopted to obtain a steering reaction force term of the equation (5) described later. In normal steering, the “threshold value Fs” is set so as to allow the estimation error so that the estimated value is adopted. If the difference between the estimated value and the detected value is larger than the threshold value, the comparing means 18 uses the actual turning reaction force detected by the turning reaction force sensor 8 to calculate the turning reaction force term of the equation (5). Ask. For example, the actual turning reaction force detected by the turning reaction force sensor 8 is used only in an abnormal situation where the estimated value is clearly significantly different from the detected value. When this actual turning reaction force is used, the value obtained from the turning reaction force sensor 8 passes through a low-pass filter to attenuate the high-frequency component included in the signal, and calculates the turning reaction force term of equation (5).

  The steering reaction force generating means 19 generates a spring reaction force proportional to the steering angle, a viscosity component proportional to the steering angular velocity, an inertia component proportional to the steering angular acceleration, a friction component, and a turning reaction force component to generate a steering reaction force. Use. That is, the steering reaction force generation means 19 adds the spring term of the first term on the right side of the formula, the viscosity term of the second term on the right side of the formula, the right term of the formula on the right side of the formula (5). The steering reaction force Tr is output by adding the inertia term of the third term and the friction term Tf of the fourth term on the right side of the equation.

  FIG. 3 is a flowchart of the processing of the steering control means 16 in this steering reaction force control apparatus. This will be described with reference to FIG. For example, this process is started when the ignition of the vehicle is turned on. In step S1, the steering control means 16 of the ECU 12 acquires the steering angle θ from the steering angle sensor 14, the vehicle speed V from the vehicle speed sensor 9, and the steering reaction force sensor value Fyb from the steering reaction force sensor 8. Next, in step S2, it is determined whether or not the acquired vehicle speed V is equal to or higher than a predetermined value Vs. If the vehicle speed is equal to or higher than the predetermined Vs (step S2: YES), the process proceeds to step S3, where the steering reaction force estimation means 17 obtains the current vehicle motion state from the vehicle motion model 20, and thereafter In step S4, an estimated value Fya of the steering reaction force is calculated and output.

In step S5, the comparison means 18 compares the estimated value Fya of the turning reaction force with the actual turning reaction force Fyb acquired by the turning reaction force sensor 8, and the difference Fys has a certain value Fys. If it is below (step S5: YES), the estimated value Fya from the vehicle motion model 20 is adopted. Next, the process proceeds to step S6 to obtain the steering reaction force term of the equation (5). Thereafter, the process proceeds to step S10.
When the vehicle speed is lower than the predetermined value Vs in step S2 (step S2: NO), or when the difference between the estimated value Fya of the turning reaction force and the actual turning reaction force Fyb is larger than the threshold value Fys (step S5) (S5: NO), the process proceeds to step S7.

  In step S7, the steering control means 16 uses the steering reaction force sensor value Fyb. The steered reaction force sensor value Fyb attenuates high frequency components included in the signal through a low-pass filter (step S8). Next, in step S9, a steering reaction force term of equation (5) based on the steering reaction force sensor value Fyb is calculated. Thereafter, the process proceeds to step S10. In step S10, the steering reaction force generating means 19 outputs the steering reaction force Tr as described above. Thereafter, the process returns to step S1.

  According to the steering reaction force control device described above, when the difference between the estimated value from the vehicle motion model 20 and the steering reaction force sensor value is a certain value or more, the steering reaction force detected by the steering reaction force sensor 8 is calculated. Use. For example, the steering reaction force that is an actual measurement value detected by the steering reaction force sensor 8 is used only in an abnormal situation where the estimated value is clearly significantly different from the detection value. When the turning reaction force is used when the vehicle speed is less than a predetermined value or when the estimated value is significantly different from the detected value as described above, the value obtained from the turning reaction force sensor 8 is: A high-frequency component included in the signal is attenuated through a low-pass filter, and a steered reaction force term is calculated. By the way, when the vehicle speed is less than a certain value, for example, when the steering wheel 1 is stationary, the stationary operation is a slow operation of, for example, 0.5 Hz or less.

  The steering reaction force generation means 19 uses the estimated value or the detection value selected by the comparison means 18 as a steering reaction force term for generating a steering reaction force. The steering reaction force is generated using the steering reaction force term, a spring element proportional to the steering angle, a viscosity element proportional to the steering angular velocity, an inertia element proportional to the steering angular acceleration, and a friction element. . Since the steering angle, the steering angular velocity, and the steering angular acceleration can be acquired by the steering angle sensor 14 in the vicinity of the steering wheel, high-frequency components due to unsprung vibrations are not included. Therefore, a stable steering reaction force that is not affected by the high-frequency component included in the acquired value of the sensor or the like used for generating the steering reaction force and that realizes a comfortable steering feeling based on the behavior state and road surface state of the vehicle. This steer-by-wire steering device can be realized.

A steering reaction force sensor 8 is provided on the tie rod 5, and the steering reaction force sensor 8 directly detects the axial force applied to the tie rod 5 as a displacement of the load support portion and converts it into an electrical signal. It becomes possible to bring the steer-by-wire steering device closer to the feeling of EPS mechanically connected to the shaft between tie rods.
The steering reaction force generating means 19 includes a spring component proportional to the steering angle (spring term), a viscosity component proportional to the steering angular velocity (viscosity term), an inertia component proportional to the steering angular acceleration (inertia term), and a friction component (friction). ) Is used to generate the steering reaction force, it is possible to prevent a sense of incongruity and vibration during operation of the steering wheel, and it is possible to obtain the same response as a steering device such as a conventional EPS.

Another embodiment will be described.
In the following description, when only a part of the configuration is described, the other parts of the configuration are the same as those described in the preceding. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

As shown in the example of FIG. 4, regarding the relationship between the steering angle θ and the spring component (Ks × θ), as the steering angle θ increases from 0 to θa degrees (θa is, for example, 120 degrees), the steering angle θ increases. The spring component, that is, a proportional relationship in which the spring term increases, may be determined so that the spring component is constant when the steering angle θ is equal to or greater than θa degrees.
As shown in the example of FIG. 5, regarding the relationship between the steering reaction force Fy and the friction component Tf, the larger the steering reaction force, the smaller the friction component, that is, the friction term, and the friction at the steering reaction force above a certain threshold. The component may be determined to be a constant value. In this case, when the turning reaction force is small, a necessary friction component can be applied according to the turning reaction force.
As shown in the example of FIG. 6, the turning reaction force coefficient Ky may be varied according to the vehicle speed V so that the turning reaction force coefficient becomes a constant value when the vehicle speed is equal to or higher than a certain speed. In this case, for example, a more stable steering reaction force can be obtained in the high speed range, and a steering reaction force that can be easily operated with a small force can be obtained in the medium / low speed range.

  A steering reaction force term obtained by multiplying a steering reaction force value estimated from the vehicle motion model 20 or a steering reaction force value detected from the steering reaction force sensor 8 by a certain coefficient is used for the steering reaction force generation means 19. However, it is not limited to this form. Instead of using the steering reaction force term, the vehicle behavior term is estimated by using any one of parameters such as yaw rate, roll rate, yaw angle, roll angle, and lateral acceleration representing the vehicle behavior estimated from the vehicle motion model 20. It may be generated. The vehicle behavior term is obtained by multiplying a coefficient corresponding to each parameter indicating the vehicle behavior.

In this case, as shown in FIG. 7, in step S1, the steering angle θ, the vehicle speed V, and the actual measurement value Fkb from the turning reaction force sensor 8 are acquired. After the conditions are classified according to the vehicle speed in step S2, the estimated value Fka of the turning reaction force and the estimated value Fkc of any parameter representing the vehicle behavior are calculated from the vehicle motion model 20 (step S3) in step S4. To do. Thereafter, in step S5, the comparison means 18 compares the estimated value Fka with the actual measurement value Fkb acquired from the turning reaction force sensor 8. If the difference is equal to or smaller than the threshold value Fks, the parameter from the vehicle motion model 20 is compared. The estimated value Fkc is used. Next, the process proceeds to step S6 to obtain the fifth term on the right side of the equation (6). In this case, the fifth term on the right side can be obtained by multiplying the estimated value Fkc by a coefficient corresponding to each parameter. In step 7, the steering reaction force Tra added with the first to fifth terms on the right side of the equation (6) is output. When the vehicle speed is less than the predetermined value Vs (step S2: NO), or when the difference between the estimated value Fka of the turning reaction force and the measured value Fkb from the turning reaction force sensor 8 is larger than the threshold value Fks in step S5. (Step S5: NO), the process proceeds to Step S8.

In step S8, the steering control means 16 uses the actual measurement value Fkb from the turning reaction force sensor 8, and this actual measurement value Fkb attenuates the high frequency component contained in the signal through a low-pass filter (step S9). Next, in step S10, the fifth term on the right side of equation (5) is obtained by multiplying the coefficient corresponding to the actual measurement value Fkb. In step S11, the steering reaction force Tr obtained by adding the first term to the fifth term on the right side of the equation (5) is output.
In the case of FIG. 7, since one of yaw rate, roll rate, yaw angle, roll angle, and lateral acceleration is estimated and used as the estimated value as a parameter representing the vehicle behavior, in the conventional steer-by-wire type steering apparatus, The vehicle behavior that could not be output can be reflected and output in the steering reaction force, and a steering device according to the preference of the operator, the type of vehicle, and the like can be realized.

DESCRIPTION OF SYMBOLS 1 ... Steering wheel 6 ... Shaft between tie rods 7 ... Steering mechanism 10 ... Acceleration sensor 13 ... Steering reaction force motor 14 ... Steering angle sensor 15 ... Steering motor 16 ... Steering control means 17 ... Steering reaction force estimation means 18 ... Comparison means 19 ... Steering reaction force generation means 20 ... Vehicle motion model

Claims (2)

A steering angle sensor that detects a steering angle, a steering reaction force motor that applies a steering reaction force to a steering wheel that is not mechanically connected to a shaft between tie rods for steering, and a steering angle that is detected by the steering angle sensor Steering control that controls the steering motor of the steering mechanism that generates the steering angle command signal and drives the shaft between the tie rods together with the driving state detection signal from other sensors mounted on the vehicle based on A steering reaction force control device in a steer-by-wire steering device having means,
The steering control means includes
Steering reaction force estimation means for calculating an estimated value of a steering reaction force or a parameter representing vehicle behavior from a vehicle motion model,
The estimated value calculated by the means for estimating the turning reaction force and the like is compared with the detection value detected from the turning reaction force sensor for detecting the turning reaction force acting on the turning mechanism, and a predetermined condition is established. According to the comparison means for selecting one of the estimated value and the detected value;
Steering reaction force generation means using the estimated value or the detection value selected by the comparison means for generating a steering reaction force,
The comparing means selects the estimated value calculated from the vehicle motion model if the vehicle speed is not less than a predetermined value as the predetermined condition, and if the vehicle speed is less than the predetermined value, A steer-by-wire steering reaction force control device that selects the detected value detected from the steering reaction force sensor. A steering angle sensor that detects a steering angle, a steering reaction force motor that applies a steering reaction force to a steering wheel that is not mechanically connected to a shaft between tie rods for steering, and a steering angle that is detected by the steering angle sensor Steering control that controls the steering motor of the steering mechanism that generates the steering angle command signal and drives the shaft between the tie rods together with the driving state detection signal from other sensors mounted on the vehicle based on A steering reaction force control device in a steer-by-wire steering device having means,
The steering control means includes
Steering reaction force estimation means for calculating an estimated value of a steering reaction force or a parameter representing vehicle behavior from a vehicle motion model,
The estimated value calculated by the means for estimating the turning reaction force and the like is compared with the detection value detected from the turning reaction force sensor for detecting the turning reaction force acting on the turning mechanism, and a predetermined condition is established. According to the comparison means for selecting one of the estimated value and the detected value;
Steering reaction force generation means using the estimated value or the detection value selected by the comparison means for generating a steering reaction force,
If the difference between the estimated value and the detected value is greater than a threshold when the vehicle speed is equal to or greater than a predetermined value, the comparing means detects the detected value detected from the turning reaction force sensor as the predetermined condition. Steer-by-wire steering reaction force control device for selecting.

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