JP2010105566A - Vehicle control characteristic changing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle control characteristic changing method that enables a continuous control change, but does not make a vehicle driver feel a sense of incongruity. <P>SOLUTION: The vehicle control characteristic changing method for a vehicle control device includes a first frequency analyzing process in which a vehicle operation input frequency analyzing part calculates a first FF frequency element ratio (λ1) that is smaller than a predetermined frequency threshold based on an operation input detected by a vehicle operation input detecting part, a second frequency analyzing process in which the vehicle operation input frequency analyzing part calculates a second FF frequency element ratio (λ2) that is smaller than the predetermined frequency threshold based on the operation input detected by the vehicle operation input detecting part after the first frequency analyzing process, and a process for determining control characteristics of the vehicle control device after the change based on a gap (Δλ) between the second FF frequency element ratio (λ2) and the first FF frequency element ratio (λ1), and the second FF frequency element ratio (λ2). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle control characteristic changing method of a vehicle control device.

  A vehicle steering apparatus that determines a driver's familiarity with respect to a steering characteristic based on a physical quantity that changes according to a difference in driving experience of operating a steering wheel of the steering apparatus, and changes the steering characteristic according to the determined familiarity However, it is disclosed in, for example, Patent Document 1 below.

Further, a comprehensive control method for changing the control characteristics of the control device in accordance with the characteristics of the user based on the determination result obtained by determining the characteristics of the user is disclosed in Patent Document 2 below.
JP 2008-087533 A JP-A-10-154002

  When the vehicle control characteristics are changed based on the driver's familiarity with operation and adaptability, the vehicle control characteristics are continuously changed so that the driver does not feel uncomfortable. There was room for further study.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a vehicle control characteristic changing method that is a continuous control change in which a driver of the vehicle does not feel uncomfortable.

  A vehicle control characteristic changing method according to the present invention includes a vehicle operation input detection unit that detects a vehicle operation input by a driver, and a vehicle operation input frequency analysis unit that performs frequency analysis of the vehicle operation input input to the vehicle operation input detection unit. A vehicle control characteristic changing method for a vehicle control device comprising: a first FF frequency component ratio that is smaller than a predetermined threshold frequency by the vehicle operation input frequency analysis unit from an operation input detected by the vehicle operation input detection unit After the first frequency analysis step for calculating (λ1) and the operation input detected by the vehicle operation input detection unit after the first frequency analysis step, a second FF frequency component ratio (λ2) smaller than a predetermined threshold frequency is calculated. Based on the second frequency analysis step to be calculated, the difference (Δλ) between the second FF frequency component ratio (λ2) and the first FF frequency component ratio (λ1), and the second FF frequency component ratio (λ2). And a step of determining the control characteristics of the vehicle control apparatus Sarago.

  According to the present invention, it is possible to provide a vehicle control characteristic changing method that is a continuous control change in which the driver of the vehicle does not feel uncomfortable.

  FIG. 1 is a flowchart for explaining a vehicle control characteristic changing method of the vehicle steering apparatus according to the embodiment. Hereinafter, the vehicle control characteristic changing method will be described in order for each step shown in FIG.

(Step S100)
If the ignition is turned on, the process proceeds to step S110.

(Step S110)
The first measurement for determining the familiarity of driving operation and the adaptability of the driver is started. That is, a steering input, for example, a value such as a steering angle, a steering angular velocity, and a steering torque is detected by a detection sensor.

(Step S120)
It is determined whether the measurement time (T) is longer than a predetermined measurement reference time (T0) and the driving operation amount (Q) is larger than a predetermined reference driving operation amount (Q0). If the measurement time (T) is larger than the predetermined measurement reference time (T0) and the driving operation amount (Q) is larger than the predetermined reference driving operation amount (Q0), the process proceeds to step S130. If the measurement time (T) is not longer than the predetermined measurement reference time (T0) and the driving operation amount (Q) is not larger than the predetermined reference driving operation amount (Q0), the process stands by in step S120.

(Step S130)
The ratio (λ1) of the FF operation component, which is a vehicle operation familiarity index by the driver, and the ratio (1-λ1) of the FB operation component are calculated. The ratio (λ1) of the FF operation component is a power spectrum density of a frequency smaller than a predetermined threshold frequency by frequency analysis of a steering input (for example, steering angle, steering angular velocity, steering torque, etc.) by the driver. Further, the ratio (1-λ1) of the FB operation component is obtained by frequency analysis of a steering input (for example, steering angle, steering angular velocity, steering torque, etc.) by the driver, and a power spectral density having a frequency larger than a predetermined threshold frequency. is there.

  Here, FIG. 2A is a diagram conceptually showing a time change of the operation input of the vehicle steering by the driver. FIG. 2B is a conceptual diagram showing the result of frequency analysis for the amount corresponding to the reference driving operation amount (Q0) with respect to the operation input of the vehicle steering by the driver.

  As shown in FIG. 2B, the ratio (λ1) of the FF operation component and the FB operation are determined depending on whether or not the predetermined threshold frequency is ω0 (v) and the frequency is greater than ω0 (v). The ratio of components (1-λ1) is discriminated. Note that the value of the predetermined threshold frequency ω0 (v) is determined depending on the vehicle speed. The ratio (λ1) of the FF operation component may be obtained by, for example, an area ratio obtained by integrating a predetermined threshold frequency with respect to a region smaller than ω0 (v).

(Step S140)
The second measurement for determining the familiarity of the driving operation and the adaptability of the driver is started. That is, a steering input, for example, a value such as a steering angle, a steering angular velocity, and a steering torque is detected by a detection sensor.

(Step S150)
It is determined whether the measurement time (T) is longer than a predetermined measurement reference time (T0) and the driving operation amount (Q) is larger than a predetermined reference driving operation amount (Q0). If the measurement time (T) is larger than the predetermined measurement reference time (T0) and the driving operation amount (Q) is larger than the predetermined reference driving operation amount (Q0), the process proceeds to step S160. If the measurement time (T) is not longer than the predetermined measurement reference time (T0) and the driving operation amount (Q) is not larger than the predetermined reference driving operation amount (Q0), the process stands by in step S150.

(Step S160)
The ratio (λ2) of the FF operation component that is a vehicle operation familiarity index by the driver and the ratio (1-λ2) of the FB operation component are calculated. The ratio (λ2) of the FF operation component is a power spectrum density of a frequency smaller than a predetermined threshold frequency by frequency analysis of a steering input (for example, steering angle, steering angular velocity, steering torque, etc.) by the driver. Further, the ratio (1-λ2) of the FB operation component is obtained by frequency analysis of a steering input (for example, steering angle, steering angular velocity, steering torque, etc.) by the driver, and a power spectral density having a frequency larger than a predetermined threshold frequency. is there.

  In the embodiment, it is determined that the driver is more accustomed to steering the vehicle as the ratio (λ2) of the FF operation component is larger.

  As shown in FIG. 2B, the ratio (λ2) of the FF operation component and the FB operation are determined depending on whether or not the predetermined threshold frequency is ω0 (v) and the frequency is higher than the predetermined threshold frequency ω0 (v). The ratio of components (1-λ2) is discriminated. The value of the predetermined threshold frequency ω0 (v) is determined depending on the vehicle speed.

(Step S170)
A difference (Δλ) in the familiarity index that is an index of the operation adaptability of the driver of the vehicle is calculated. That is, the adaptive power index (Δλ) = (λ2−λ1).

(Step S180)
A new vehicle control characteristic is calculated according to the familiarity index (λ2) and the adaptive power index (Δλ).

(Step S190)
The vehicle control characteristic is changed to the new vehicle control characteristic calculated in step S180. Here, it is assumed that the larger the adaptive power index is, the smaller the operation input is. That is, if the adaptive power index is large, the reference driving operation amount (Q0) can be set to a smaller value.

  A method for changing the vehicle control characteristics will be briefly described.

  f is the vehicle characteristic during the characteristic change, f0 is the vehicle characteristic before the characteristic change, f 'is the vehicle characteristic after the change, Q is the driving operation amount by the driver, and Q1 is the changed reference driving operation amount. Then, the following formula (1) is obtained.

  By changing the vehicle control characteristics as described above, the vehicle control characteristics can be changed with fewer operation inputs as the driver has an adaptability to the operation. In the vehicle control characteristic changing method described above, the change reference driving operation amount (Q1) is set to be inversely proportional to the ratio (λ1) of the FF operation component calculated from the first measurement.

  By adapting the changed reference driving operation amount (Q1) to be inversely proportional to the ratio (λ1) of the FF operation component calculated from the first measurement, it is possible to adapt to the vehicle characteristics from the beginning. The change reference driving operation amount (Q1) of the driver with high power and the change reference driving operation amount (Q1) of the driver with low adaptability can be set to different values.

  The characteristics relating to the driving operation such as the vehicle motion and the small steering angle steer are not only familiar to the characteristics but also required characteristics depending on the driving skill possessed by each driver. The vehicle control characteristic changing method described above uses not only the indexed habituation and the indexed adaptability that is one of the driving skills, but also reconstructs the vehicle characteristics according to them, as well as the vehicle driver. The present invention proposes a method for continuously and efficiently transitioning to a characteristic reconstructed from the current characteristic on the basis of the adaptive power of the system while reducing a sense of incongruity.

  Note that changing the steering control characteristics so as to facilitate the driving of the vehicle according to the driver's familiarity with the steering of the vehicle is also disclosed in, for example, Japanese Patent Application Laid-Open No. 2008-87533. The configuration of the vehicle control device, which is a vehicle steering device as a typical example, is considered to be well known to those skilled in the art, but the configuration overview and the operation overview will be described below as an example.

  FIG. 3 is a diagram schematically illustrating a vehicle steering apparatus 100 that employs the steering-by-wire system according to the embodiment. The steering device 100 includes a steering handle 11 that is turned by a driver to steer left and right front wheels FW1 and FW2 as steered wheels. The steering handle 11 is fixed to the upper end of the steering input shaft 12, and the lower end of the steering input shaft 12 is connected to a reaction force actuator 13 including an electric motor and a speed reduction mechanism. The reaction force actuator 13 applies a reaction force to the turning operation of the steering handle 11 by the driver.

  Further, the steering device 100 includes a steering actuator 21 including an electric motor and a speed reduction mechanism. The turning force by the turning actuator 21 is transmitted to the left and right front wheels FW1, FW2 via the turning output shaft 22, the pinion gear 23, and the rack bar 24. With the above-described configuration, the rotational force from the steering actuator 21 is transmitted to the pinion gear 23 via the steering output shaft 22, and the rack bar 24 is displaced in the axial direction by the rotation of the pinion gear 23. The left and right front wheels FW1, FW2 are steered left and right by the displacement in the axial direction.

  An electric control device that controls the operation of the reaction force actuator 13 and the steering actuator 21 will be described. The electric control device includes a steering angle sensor 31, a turning angle sensor 32, a vehicle speed sensor 33, a lateral acceleration sensor 34, and a yaw rate sensor 35. The steering angle sensor 31 is assembled to the steering input shaft 12, detects the rotation angle from the neutral position of the steering handle 11, and outputs it as the steering angle θ.

  The turning angle sensor 32 is assembled to the turning output shaft 22, detects the rotation angle from the neutral position of the turning output shaft 22 and corresponds to the actual turning angle δ (corresponding to the turning angle of the left and right front wheels FW1, FW2). Output as. Here, the neutral position is an operating position of the steering handle 11, the steering input shaft 12, the steering output shaft 22, and the left and right front wheels FW1, FW2 for maintaining the vehicle in a straight traveling state. Further, regarding the steering angle θ and the turning angle δ, the neutral position is “0”, the left rotation angle is represented by a positive value, and the right rotation angle is represented by a negative value.

  The vehicle speed sensor 33 detects and outputs the vehicle speed V. The lateral acceleration sensor 34 detects and outputs the actual lateral acceleration G of the vehicle. The yaw rate sensor 35 detects and outputs the actual yaw rate γ of the vehicle. Note that the actual lateral acceleration G and the actual yaw rate γ are also expressed as positive acceleration and yaw rate in the left direction and negative acceleration and yaw rate in the right direction.

  The sensors 31 to 35 are connected to the electronic control unit 36. The electronic control unit 36 is mainly composed of a microcomputer composed of a CPU, EEPROM, RAM, timer, and the like. Further, the electronic control unit 36 controls the operations of the reaction force actuator 13 and the turning actuator 21 by executing various programs including a program to be described later.

  Drive circuits 37 and 38 for driving the reaction force actuator 13 and the steering actuator 21 are connected to the output side of the electronic control unit 36, respectively. In the drive circuits 37 and 38, current detectors 37a and 38a for detecting a drive current flowing through the electric motor in the reaction force actuator 13 and the steering actuator 21 are provided. The drive current detected by the current detectors 37a and 38a is fed back to the electronic control unit 36 in order to control the drive of both electric motors.

  The steering-by-wire steering device 100 is a steering device 100 that can relatively rotate the steering output shaft 22 with respect to the rotation of the steering input shaft 12. Next, the operation of the steering device 100 will be described. In general, when a driver who has a long operation experience of the normal steering device 100 in which the steering input shaft and the steering output shaft do not rotate relative to each other operates the steering device 100 of the steering-by-wire system, It is necessary to get used to the difference in steering characteristics that express the relationship between operation and reaction force characteristics and steering characteristics. The degree of familiarity with this difference in steering characteristics (hereinafter referred to as the degree of familiarity) varies depending on the driver.

  For this reason, the electronic control unit 36 executes a steering characteristic changing program shown in FIG. 4 in order to change the steering characteristic of the steering-by-wire system as appropriate in consideration of the driver's familiarity. Therefore, this steering characteristic changing program will be specifically described. When an ignition switch (not shown) is turned on, the electronic control unit 36 repeatedly executes the steering characteristic changing program every predetermined short time.

(Step S10)
The electronic control unit 36 starts executing the steering characteristic changing program.

(Step S11)
The electronic control unit 36 inputs each detection value detected by the sensors 31 to 35.

(Step S12)
The electronic control unit 36 estimates and determines the familiarity degree coefficient Nk_0 representing the familiarity degree with respect to the steering characteristics of the driver who has boarded. However, the familiarity coefficient Nk_0 is a variable that changes from “0” to “1”, and is determined to be a value closer to “0” as the driver who gets on the vehicle becomes less familiar with the steering characteristics. It is assumed that the value is closer to “1” as the value increases.

  Here, the electronic control unit 36 is a travel distance and travel time in which the driver has operated the steering device 100 to drive the vehicle, the number of correction rotation operations of the steering handle 11 when the vehicle is turning, and the rotation of the steering handle 11. The familiarity degree coefficient Nk_0 is estimated and determined based on a comprehensive physical quantity mainly related to the driving experience of the driver, such as the behavior change amount of the vehicle accompanying the operation.

  Steering characteristics are improved as the travel distance and travel time of the vehicle on which the steering device 100 is mounted are shorter, the number of correction turning operations of the steering handle 11 during turning is greater, or the behavior change amount of the vehicle is greater. Presumed to be unfamiliar.

  Therefore, the electronic control unit 36, for example, the current travel distance and travel time of the vehicle, the number of corrective turning operations of the steering handle 11 during turning, the actual input from the lateral acceleration sensor 34 and the yaw rate sensor 35 in the step S11. Based on the amount of change in the lateral acceleration G and the actual yaw rate γ, the familiarity degree coefficient Nk_0 is estimated and determined.

(Step S13)
The electronic control unit 36 determines whether or not the absolute value of the detected steering angle θ input from the steering angle sensor 31 in step S11 is decreased, in other words, whether or not the steering handle 11 is in the switchback operation state. If the absolute value of the detected steering angle θ has decreased, the process proceeds to step S14. If the absolute value of the detected steering angle θ has not decreased, the process proceeds to step S15.

(Step S14)
The electronic control unit 36 corrects the familiarity degree coefficient Nk_0 determined in step S12 according to the switchback operation state. Specifically, when the steering output shaft 22 is rotatable relative to the steering input shaft 12 as in the steering device 100, the rotation amount of the steering input shaft 12 and the steering output shaft 22 The ratio (for example, gear ratio) with the rotation amount can be changed as appropriate.

  Thereby, the turning amount of the left and right front wheels FW1, FW2 can be changed with respect to the turning operation amount of the steering handle 11, and the vehicle can be easily turned or the turning behavior can be stabilized. In such a steering characteristic, especially when the steering handle 11 is turned back, the steering operation of the left and right front wheels FW1 and FW2 may be quick, and as a result, the steering characteristic in the steering-by-wire system has become familiar. Even the driver may feel uncomfortable in the steering operation of the left and right front wheels FW1, FW2.

  Therefore, the electronic control unit 36 sets the corrected familiarity degree coefficient Nk_1 corrected so that the value of the familiarity degree coefficient Nk_0 determined in step S12 becomes small when the steering handle 11 is in the return operation state.

(Step S15)
The electronic control unit 36 determines the familiarity degree coefficient Nk_0 determined in step S12 as the corrected familiarity degree coefficient Nk_1 in order to correspond to each subsequent step process.

(Step S16)
In order to steer the left and right front wheels FW1, FW2 in accordance with the familiarity degree coefficient Nk_0 determined in step S12, the electronic control unit 36, for example, sets a target turning angle δd that changes in a power function as the following formula (2): Calculate according to

δd = (1 / Kg) · a · θI (2)
However, a in the formula (2) is a vehicle speed coefficient that changes according to the detected vehicle speed V input from the vehicle speed sensor 33 in step S11, and is larger than “1” within a range where the detected vehicle speed V is small. It is assumed that the detected vehicle speed V is smaller than “1” within a large range and decreases nonlinearly with “1” sandwiched as the detected vehicle speed V increases. As the vehicle speed coefficient a, a ratio of the rotation amount of the steered output shaft 22 to the rotation amount of the steering input shaft 12, for example, a transmission ratio or a gear ratio can be employed.

  In the equation (2), θ represents the absolute value of the detected steering angle θ input from the steering angle sensor 31 in step S11. If the detected steering angle θ is a positive value, the vehicle speed coefficient a If the detected steering angle θ is a negative value, the value of the vehicle speed coefficient a is a negative value having the same absolute value as the positive value. Furthermore, I in the formula (2) is a constant representing a power index, and is set to a value larger than “1”.

  Further, Kg in the formula (2) is a turning amount correction coefficient that changes in accordance with the familiarity degree coefficient Nk_0 determined in step S12. That is, as the familiarity degree coefficient Nk_0 becomes smaller, that is, the driver As the steering characteristics become unfamiliar, it changes to a large value Kg0, and as the familiarity degree coefficient Nk_0 increases, that is, it has a characteristic that changes to a small value (for example, “1”) as the driver gets used to the steering characteristics. To do.

  Thus, by changing the steering amount correction coefficient Kg according to the familiarity degree coefficient Nk_0, the left and right front wheels FW1 and FW2 can be steered according to the familiarity of the steering characteristics of the steering-by-wire system by the driver. .

  When the driver who is unfamiliar with the steering characteristics of the steering-by-wire system, that is, when the familiarity degree coefficient Nk_0 is determined to be a value close to “0”, the turning amount correction coefficient Kg is set to a large value. As a result, the value of the target turning angle δd that changes in a power function with respect to the change in the detected steering angle θ is calculated to be relatively smaller than the turning operation of the steering handle 11 by the driver. The front wheels FW1 and FW2 can be gently steered. Therefore, even a driver who is not familiar with steering characteristics of the steering-by-wire system can easily turn the vehicle.

  When the driver who is used to the steering characteristics of the steering-by-wire system, that is, the familiarity degree coefficient Nk_0 is determined to be a value close to “1”, the turning amount correction coefficient Kg is set to a small value. As a result, the value of the target turning angle δd that changes in a power function is calculated to be relatively large. As a result, the left and right front wheels FW1, FW2 can be quickly turned.

  Therefore, when the driver is accustomed to the steering characteristics of the steering-by-wire system, for example, the vehicle can be easily turned with a small turning amount of the steering handle 11 in the low speed range.

(Step S17)
The electronic control unit 36 responds to the turning operation of the left and right front wheels FW1, FW2 with respect to the turning operation of the steering handle 11 by the driver according to the value of the corrected habituation degree coefficient Nk_1 determined in step S14 or step S15. To change. That is, the electronic control unit 36 changes the time constant τ of the soft filter provided in the drive circuit 38 according to the value of the corrected familiarity degree coefficient Nk_1. Here, the time constant τ has a characteristic that changes to a large value τ0 as the value of the corrected habituation degree coefficient Nk_1 decreases and changes to a small value as the value of the corrected habituation degree coefficient Nk_1 increases. Shall.

  The electronic control unit 36 sets the time constant τ to a large value if the corrected familiarity degree coefficient Nk_1 is small, that is, if the driver is not accustomed to the steering characteristics of the steering-by-wire system. As a result, the operation start timing of the steering actuator 21 (more specifically, the electric motor) that is driven and controlled according to the turning operation of the steering handle 11 by the driver can be slightly delayed, and the left and right front wheels FW1 and FW2 are steered. The responsiveness of operation can be made dull.

  Therefore, even when a driver unfamiliar with the steering characteristics of the steering-by-wire method turns the steering handle 11 relatively quickly, the abrupt turning operation of the left and right front wheels FW1, FW2 is suppressed, and the steering by the driver It is possible to satisfactorily suppress the vehicle behavior disturbance caused by the turning operation of the handle 11.

  On the other hand, the electronic control unit 36 sets the time constant τ to a small value if the corrected familiarity degree coefficient Nk_1 is large, that is, if the driver is accustomed to the steering characteristics of the steering-by-wire system. As a result, the operation start timing of the steering actuator 21 (more specifically, the electric motor) with respect to the turning operation of the steering handle 11 by the driver can be advanced, and the responsiveness of the steering operation of the left and right front wheels FW1, FW2 can be agile. Can be.

  Therefore, a driver who is used to the steering characteristics of the steering-by-wire system can turn the vehicle crisply in accordance with the turning operation of his / her steering handle 11.

(Step S18)
The electronic control unit 36 sets the target reaction force torque Tz to be applied to the turning operation of the steering handle 11 by the driver according to the value of the corrected familiarity degree coefficient Nk_1 determined in step S14 or step S15, using the following equation (3 )

Tz = Ks · Ts + Kf · Tf + Kr · Tr (3)
However, Ts in the equation (3) represents a spring term component torque that changes in accordance with the magnitude of the detected steering angle θ input from the steering angle sensor 31 in step S11, and Tf represents the time of the detected steering angle θ. The friction term component torque that changes according to the magnitude of the differential value dθ / dt (hereinafter, this differential value is referred to as the steering angular velocity dθ / dt), and Tr represents the viscosity that changes according to the magnitude of the steering angular velocity dθ / dt. This represents the term component torque.

  Here, the spring term component torque Ts, the friction term component torque Tf, and the viscosity term component torque Tr will be briefly described. The spring term component torque Ts is proportional to the detected steering angle θ, and the electronic control unit 36 calculates the spring term component torque Ts with respect to the detected steering angle θ using a predetermined conversion table. The friction term component torque Tf depends on the magnitude of the steering angular velocity dθ / dt and has a hysteresis characteristic. The electronic control unit 36 uses the predetermined conversion table and the friction term component torque with respect to the steering angular velocity dθ / dt. Calculate Tf. The viscosity term component torque Tr is proportional to the steering angular velocity dθ / dt, and the electronic control unit 36 calculates the viscosity term component torque Tr with respect to the steering angular velocity dθ / dt using a predetermined conversion table.

  Further, the coefficients Ks, Kf, Kr in the equation (3) are correction coefficients that change in accordance with the correction familiarity degree coefficient Nk_1 determined in step S14 or step S15. Specifically, the correction coefficient Ks is a correction coefficient for correcting the spring component term torque Ts, and changes to a large value Ks0 as the correction habituation degree coefficient Nk_1 decreases, and the correction habituation degree coefficient Nk_1 It is assumed that it has a characteristic that changes to a smaller value as it increases.

  Further, the correction coefficient Kf is a correction coefficient for correcting the friction component term torque Tf, and changes to a large value Kf0 as the correction familiarity degree coefficient Nk_1 decreases, and the correction familiarity degree coefficient Nk_1 increases. It shall have the characteristic which changes to a small value with. Further, the correction coefficient Kr is a correction coefficient for correcting the viscous component term torque Tr, and changes to a large value Kr0 as the correction familiarity degree coefficient Nk_1 decreases, and the correction familiarity degree coefficient Nk_1 increases. It shall have the characteristic which changes to a small value with.

  The electronic control unit 36 calculates the target reaction force torque Tz corresponding to the corrected familiarity degree coefficient Nk_1 determined in step S14 or step S15. That is, if the corrected familiarity degree coefficient Nk_1 is small, the electronic control unit 36 sets the correction coefficients Ks, Kf, Kr to large values and increases the target reaction force torque Tz calculated according to the above equation (3). As a result, a large turning operation of the steering handle 11 by a driver unfamiliar with steering-by-wire steering characteristics can be suppressed.

  On the other hand, if the correction familiarity degree coefficient Nk_1 is large, the electronic control unit 36 sets the correction coefficients Ks, Kf, and Kr to small values, and decreases the target reaction force torque Tz calculated according to the equation (3). As a result, a driver who is used to the steering characteristics of the steering-by-wire system can easily turn the steering handle 11.

(Step S19)
Based on the target turning angle δd calculated in step S16, the time constant τ set in step S17, and the target reaction torque Tz calculated in step S18, the electronic control unit 36 reacts to the reaction force actuator 13. And the operation of the steering actuator 21 is controlled. Hereinafter, the reaction force control will be specifically described.

  The electronic control unit 36 inputs a drive current flowing from the current detector 37a provided in the drive circuit 37 to the electric motor in the reaction force actuator 13, and the drive current corresponding to the target reaction force torque Tz is input to the electric motor. The drive circuit 37 is feedback controlled so as to flow. By the drive control of the electric motor in the reaction force actuator 13, the electric motor applies a reaction force corresponding to the target reaction force torque Tz to the steering handle 11 via the steering input shaft 12.

  Next, turning control will be specifically described. The electronic control unit 36 inputs the actual turning angle δ detected by the turning angle sensor 32, and turns the turning actuator so that the turning output shaft 22 rotates to the target turning angle δd calculated in step S16. The rotation of the electric motor in 21 is feedback controlled. At this time, the electronic control unit 36 inputs a drive current flowing from the current detector 38a provided in the drive circuit 38 to the electric motor in the steering actuator 21, and the electric motor has a magnitude corresponding to the steering force. The drive circuit 38 is feedback-controlled so that the drive current of the current flows appropriately.

  The electronic control unit 36 also drives the drive circuit 38 so that the electric motor in the steered actuator 21 generates drive force based on the time constant τ of the soft filter provided in the drive circuit 38 set in step S17. To control. Thereby, the pinion gear 23 integrally assembled with the steering output shaft 22 rotates, and the rack bar 24 is displaced in the axial direction by the rotation of the pinion gear 23. Then, due to the displacement of the rack bar 24 in the axial direction, the left and right front wheels FW1, FW2 are steered corresponding to the target turning angle δd.

  When the electronic control unit 36 controls the operation of the reaction force actuator 13 and the steering actuator 21, the reaction force actuator 13 applies an appropriate reaction force to the driver according to the corrected familiarity degree coefficient Nk_1 (that is, the familiarity degree coefficient Nk_0). Can be given to the turning operation of the steering handle 11 by.

  Further, the steering actuator 21 can appropriately steer the left and right front wheels FW1, FW2 according to the familiarity degree coefficient Nk_0. Therefore, when driving the steering device 100, that is, a vehicle equipped with the steering device 100 in which the steering input shaft 12 and the steering output shaft 22 can be rotated relative to each other, the optimum according to the driver's familiarity with the steering characteristics. Steering characteristics and reaction force characteristics can be provided, and the driver can drive the vehicle very easily without feeling uncomfortable with the transfer.

(Step S20)
The electronic control unit 36 once terminates execution of the steering characteristic changing program. Then, after a predetermined short time has elapsed, the electronic control unit 36 returns to step S10 and starts execution of the steering characteristic change program, and responds according to the familiarity degree coefficient Nk_0 (corrected familiarity degree coefficient Nk_1). The force actuator 13 and the steering actuator 21 are operated.

  When driving the steering device 100, it changes according to the difference in experience of operating the steering handle 11, more specifically, the difference in driving experience such as the travel distance and travel time of driving the vehicle on which the steering device 100 is mounted. The driver's habituation degree coefficient Nk_0 with respect to the steering characteristics can be determined based on the number of correction rotation operations of the steering handle 11, the lateral acceleration G, the amount of change in the yaw rate γ, and the like as physical quantities to be performed.

  Then, according to the determined familiarity coefficient Nk_0, if the driver is unfamiliar with the steering characteristic, the reaction force characteristic is changed to apply a large reaction force torque Tz to suppress a large operation of the steering handle 11. Or the left and right front wheels FW1, FW2 can be changed to a turning characteristic that turns gently.

  Furthermore, the operations of the reaction force actuator 13 and the turning actuator 21 can be controlled based on the changed steering characteristics. Therefore, an appropriate steering characteristic can be set according to the degree of familiarity with the driver's steering characteristic, and the driver can easily drive the vehicle.

  The above is an example of the configuration overview and operation overview of the steering device that changes the steering control characteristics so as to facilitate the driving of the vehicle according to the degree of vehicle steering familiarity with the driver, and the description of the operation processing.

  The method for changing the vehicle control characteristics described above is not limited to the operation processing described in the embodiment, and the configuration of the vehicle control device and the operation processing for changing the control characteristics are appropriately set within the obvious range based on the disclosed technical idea. It is easily understood by those skilled in the art that the above can be changed. Further, the vehicle control characteristic changing method according to the present invention is not limited to the vehicle steering device, but may be applied to other vehicle control devices.

It is a flowchart explaining the control characteristic change method of the vehicle steering device concerning embodiment. FIG. 2A is a diagram conceptually showing a time change of an operation input for steering the vehicle by the driver. FIG. 2B is a conceptual diagram showing the result of frequency analysis for the amount corresponding to the reference operation amount. It is a figure showing roughly the steering device of vehicles which adopted the steering by wire system. It is a flowchart which illustrates a steering characteristic change program.

Explanation of symbols

  11 .... steering handle, 12 .... steering input shaft, 13 .... reaction actuator, 21 ... steering actuator, 22 .... steering output shaft, 23 ... pinion gear, 24 ... rack bar.

Claims (1)

A vehicle operation input detection unit for detecting an input of a vehicle operation by a driver;
A vehicle operation input frequency analysis unit for analyzing a frequency of a vehicle operation input input to the vehicle operation input detection unit;
In a vehicle control characteristic changing method of a vehicle control device comprising:
The vehicle operation input frequency analysis unit is
A first frequency analysis step of calculating a first FF frequency component ratio (λ1) smaller than a predetermined threshold frequency from the operation input detected by the vehicle operation input detection unit;
A second frequency analysis step of calculating a second FF frequency component ratio (λ2) smaller than the predetermined threshold frequency from the operation input detected by the vehicle operation input detection unit after the first frequency analysis step;
The vehicle after the change based on the difference (Δλ) between the second FF frequency component ratio (λ2) and the first FF frequency component ratio (λ1) and the second FF frequency component ratio (λ2). Determining the control characteristics of the control device;
A vehicle control characteristic changing method comprising:

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