JP2009006742A - Steering device and setting method for steering reaction force - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress vibration level when vibration occurs with a steering wheel when hysteresis characteristic is given to a steering reaction force characteristic when feeding or getting back a turn of steering wheel. <P>SOLUTION: When a steering reaction force command value Tp* is on a second characteristic line (for example, B and D), the inclination of the steering reaction force command value Tp* is increased from K2 to K1 when the direction of feeding and returning of the steering wheel is changed. When the steering reaction force command value Tp* is on a first characteristic line (for example, A2), the inclination of the steering reaction force command value Tp* is decreased from K1 to K2 when a steering angle θh reaches the angle corresponding to the intersection of the first characteristic line and the second characteristic line. When the vibration level of the steering angle θh is not less than a predetermined level, the inclination on the first characteristic line is set to K3 smaller than K1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a steering device and a steering reaction force setting method, and more specifically, an in-vehicle steering device that outputs a steering reaction force according to the operation of the steering wheel, and a steering reaction force according to the operation of the steering wheel of the vehicle. The present invention relates to a steering reaction force setting method.

  Conventionally, as this type of steering device, as disclosed in Patent Document 1 below, a steering reaction force is set with hysteresis characteristics based on the steering angle of the steering wheel and the determination result of the steering wheel turning back and forth. Has been proposed. The hysteresis characteristic here is the first characteristic in which the steering reaction force changes with the first inclination K1 with respect to the change in the steering angle, and the steering reaction force with respect to the change in the steering angle with respect to the first inclination K1. And a second characteristic that changes with a small second inclination K2, and when the steering reaction force with respect to the steering angle is on the second characteristic, the steering angle is increased and the return direction is changed. When the steering reaction force with respect to the steering angle changes from the second inclination K2 to the first inclination K1 and the steering reaction force with respect to the steering angle is on the first characteristic, the steering angle is the first characteristic and the second characteristic. When the angle corresponding to the intersection with is reached, the inclination of the steering reaction force with respect to the steering angle changes from the first inclination K1 to the second inclination K2. In this steering apparatus, by increasing the value of the first inclination K1, a hysteresis that approximates Coulomb friction is given to the steering reaction force characteristic by a spring element having a high rigidity (spring constant), and the hysteresis characteristic that does not depend on the steering speed is obtained. It is reproduced.

Japanese Patent No. 3889916

  In the above steering device, when the minimum resolution of the steering angle sensor for detecting the steering angle of the steering wheel is not sufficiently high, self-excited vibration is likely to be generated in the steering wheel. It will make you feel uncomfortable and uncomfortable. By reducing the value of the first slope K1 in the hysteresis characteristic, the level of self-excited vibration can be reduced, but on the other hand, the hysteresis characteristic due to Coulomb friction cannot be sufficiently obtained, and the steering feeling is reduced. This is a trade-off relationship of lowering.

  An object of the present invention is to suppress the vibration level when vibration is generated in the steering wheel when hysteresis is given to the steering reaction force characteristics when the steering wheel is additionally turned and turned back.

  The steering device and the steering reaction force setting method according to the present invention employ the following means in order to achieve the above-described object.

  The steering device according to the present invention is a vehicle-mounted steering device that outputs a steering reaction force corresponding to the operation of the steering wheel, and is based on the steering angle detection means that detects the steering angle of the steering wheel, and the detected steering angle. A turning-up / back-off judging means for judging whether the steering wheel is turned up and down, a vibration level computing means for computing a vibration level of the steering angle based on the detected steering angle, and a turning-up / back-back judging means Target steering reaction force setting means for setting the target steering reaction force with hysteresis characteristics based on the determination result and the detected steering angle, and outputting the steering reaction force so that the set target steering reaction force is output A steering reaction force output means, wherein the hysteresis characteristic includes a first characteristic in which the steering reaction force changes with a first inclination with respect to a change in the steering angle, and a steering reaction force with respect to a change in the steering angle. Smaller than the first inclination A second characteristic that changes with a second inclination, and when the steering reaction force with respect to the steering angle is on the second characteristic, the steering angle is increased and the return direction is changed. When the steering reaction force inclination with respect to the steering angle changes from the second inclination to the first inclination and the steering reaction force with respect to the steering angle is on the first characteristic, the steering angle is the first characteristic and the first characteristic. When the angle corresponding to the intersection with the second characteristic is reached, the inclination of the steering reaction force with respect to the steering angle is a characteristic that changes from the first inclination to the second inclination, and the target steering reaction force setting means When the vibration level calculated by the vibration level calculation means is equal to or higher than a predetermined level, the inclination of the steering reaction force with respect to the steering angle in the first characteristic is changed to a third inclination smaller than the first inclination. The gist is to set.

  In one aspect of the present invention, the target steering reaction force setting means has a steering angle within a set range including the vibration center when the vibration level calculated by the vibration level calculation means is equal to or greater than the predetermined level. It is preferable that the inclination of the steering reaction force with respect to the steering angle in the first characteristic is set to the third inclination under the condition.

  In one aspect of the present invention, the steering angle detecting means is means for detecting a steering angle with a predetermined resolution Δθh, and the setting range has an upper limit value obtained by adding Δθh to the vibration center of the steering angle. It is preferable that the lower limit is a value obtained by subtracting Δθh from the angular vibration center.

  In one aspect of the present invention, it is preferable that the target steering reaction force setting unit changes the setting range according to the vibration level calculated by the vibration level calculation unit. In this aspect, it is preferable that the target steering reaction force setting means increases the setting range with respect to an increase in the vibration level calculated by the vibration level calculation means.

  In one aspect of the present invention, it is preferable that the target steering reaction force setting unit changes the third inclination according to a vibration level calculated by the vibration level calculation unit. In this aspect, it is preferable that the target steering reaction force setting unit decreases the third inclination with respect to an increase in the vibration level calculated by the vibration level calculation unit.

  In one aspect of the present invention, the vibration level calculation means includes a resonance frequency of a handle that is determined based on the first inclination or the second inclination with respect to the steering angle detected by the steering angle detection means. It is preferable to calculate the vibration level of the steering angle after performing a filter process for passing the band. In this aspect, the target steering reaction force setting means determines whether a steering reaction force with respect to a steering angle is on the first characteristic or the second characteristic, and the vibration level calculation means is It is preferable to change the pass band in the filter processing according to the determination result.

  The steering reaction force setting method according to the present invention is a steering reaction force setting method for setting a steering reaction force according to an operation of a steering wheel of a vehicle, wherein only the steering wheel is increased based on the steering angle of the steering wheel. In the steering reaction force setting method of determining whether to return and setting a steering reaction force with a hysteresis characteristic based on the determination result and the steering angle of the steering wheel, the hysteresis characteristic is a steering reaction force against a change in the steering angle. A first characteristic that changes with a first inclination, and a second characteristic that a steering reaction force changes with a second inclination that is smaller than the first inclination with respect to a change in steering angle. When the steering reaction force with respect to the angle is on the second characteristic and the direction of the steering wheel turning back and forth changes, the inclination of the steering reaction force with respect to the steering angle changes from the second inclination to the first inclination. To the steering angle When the steering reaction force is on the first characteristic, when the steering angle reaches an angle corresponding to the intersection of the first characteristic and the second characteristic, the inclination of the steering reaction force with respect to the steering angle is A characteristic that changes from the first inclination to the second inclination, and when setting the steering reaction force, the vibration level of the steering angle is calculated based on the steering angle of the steering wheel, and the calculated vibration When the level is equal to or higher than a predetermined level, the gist is to set the inclination of the steering reaction force with respect to the steering angle in the first characteristic to a third inclination smaller than the first inclination.

  According to the present invention, it is possible to suppress the vibration level when vibration occurs in the steering wheel when hysteresis is given to the steering reaction force characteristics when the steering wheel is additionally turned and turned back.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a steering device 20 according to an embodiment of the present invention. A steering device 20 according to the present embodiment is mounted on a vehicle. As shown in the figure, a steering wheel 22 operated by a driver, a steering angle sensor 24 for detecting an angle (steering angle) of the steering wheel 22, and A torque sensor 26 for detecting the torque (steering reaction force) of the handle 22 and a reaction force motor 40 for simulating the steering reaction force of the handle 22 by applying a torque to the handle 22 in accordance with the operation of the handle 22 by the driver. And a steering motor 42 that transmits an output torque for changing the turning angle of the steering wheels 30 and 32 according to the steering angle of the steering wheel 22 to the rack 36 via the reduction gear 34 and outputs the output torque to the steering wheels 30 and 32. And an electronic control unit 50 for controlling the entire apparatus.

  The electronic control unit 50 is configured as a microprocessor centered on a CPU 52, and includes a ROM 54 that stores a processing program, a RAM 56 that temporarily stores data, and an input / output port (not shown). A steering angle θh from the steering angle sensor 24, a torque Th from the torque sensor 26, a vehicle speed V from the vehicle speed sensor 58, and the like are input to the electronic control unit 50 through an input port. Further, the electronic control unit 50 outputs drive signals to the reaction force motor 40 and the steering motor 42 through the output port.

  FIG. 2 is an explanatory diagram illustrating a control block when the electronic control unit 50 of the steering device 20 operates as the steering reaction force command value calculation block 60 for calculating the steering reaction force command value Tp *. As shown in the figure, the steering reaction force command value calculation block 60 is configured to add an increase / return determination unit 62 that determines whether the handle 22 is increased or decreased based on the input steering angle θh, and to input the steering angle θh. Based on the vibration level detection unit 64 that detects the vibration level (amplitude) of the steering wheel 22 (steering angle θh), the determination result of the additional switching / return determination unit 62, the vibration level detected by the vibration level detection unit 64, and the steering A steering reaction force command value calculation unit 66 for calculating a steering reaction force command value Tp * based on the angle θh and the vehicle speed V. In the electronic control unit 50, the steering reaction force acting on the handle 22 is steered based on the steering reaction force command value Tp * calculated by the steering reaction force command value calculation block 60 and the torque Th detected by the torque sensor 26. The reaction force motor 40 is driven and controlled so that the reaction force command value Tp * is obtained. However, here, the reaction force motor 40 may be driven and controlled based only on the steering reaction force command value Tp * without using the torque sensor 26. The steering angle θh is detected by the steering angle sensor 24 with a predetermined resolution (minimum resolution) Δθh.

  The increase / return determination unit 62 in the steering reaction force command value calculation block 60 determines whether the handle 22 is in the increased state or the reverted state based on the steering angle θh detected by the steering angle sensor 24. Is done. More specifically, the sign of the difference between the steering angle θh input last time and the steering angle θh input this time, that is, whether it is increased or decreased is determined by positive / negative.

  The vibration level detection unit 64 performs a band pass filter process for passing the set frequency band with respect to the input steering angle θh. Here, the band corresponding to the resonance frequency of the handle 22 is set by setting the pass band of the band-pass filter so as to pass the frequency band including the resonance frequency of the handle 22 determined based on the inertia and rigidity of the handle 22. The frequency component of the angle θh is extracted. The steering angle θh after the band-pass filter process is subjected to a low-pass filter process after a square process is performed by the vibration level detector 64 to detect the vibration level. By this process, the vibration level of the steering angle θh corresponding to the resonance frequency of the handle 22 is calculated.

  In the steering reaction force command value calculation unit 66, the steering reaction force acting on the steering wheel 22 based on the determination result of the additional switching / return determination unit 62, the vibration level detected by the vibration level detection unit 64, the steering angle θh, and the vehicle speed V. The steering reaction force command value Tp * is calculated so that the force has a hysteresis characteristic as illustrated in FIG. In FIG. 3, the horizontal axis is the steering angle θh, and the vertical axis is the steering reaction force Tp. The hysteresis characteristic illustrated in FIG. 3 includes the straight lines A and C (first characteristic lines) in which the steering reaction force Tp changes with the inclination K1 with respect to the change in the steering angle θh, and the steering reaction with respect to the change in the steering angle θh. This is a characteristic including straight lines B and D (second characteristic lines) in which the force Tp changes with a slope K2 (K2 <K1). In FIG. 3, the intercept of the straight line B is T0, and the intercept of the straight line D is -T0. Hereinafter, processing in which the steering reaction force command value calculation unit 66 calculates the steering reaction force command value Tp * will be described. The steering reaction force command value Tp * is calculated in the same way except that the sign differs between when the handle 22 is rotated to the right and when the handle 22 is rotated to the left. In the embodiment, the case where the handle 22 is rotated to the left will be described. For ease of explanation, a process for calculating the steering reaction force command value Tp * without using the vehicle speed V will be described.

  When the steering angle θh at the start of turning of the steering wheel 22 reaches the angle θ1 that intersects the straight line B on the straight line with the inclination K1 from the value 0, the steering angle θh and the steering reaction force Tp are set as the horizontal axis and the vertical axis. A steering reaction force command value Tp * is calculated as a straight line relationship passing through the origin with an inclination K1 on the coordinates. That is, the steering reaction force command value Tp * is calculated as the following equation (1).

  Tp * = K1 · θh (1)

  When the steering angle θh is increased after exceeding the angle θ1, every time the steering angle θh is increased by the minimum resolution Δθh, ΔT calculated by the following equation (2) is added. That is, when the value is increased by n times the minimum resolution Δθh, the steering reaction force command value Tp * is calculated by the equation (3).

ΔT = K2 · Δθh (2)
Tp * = K1 · θ1 + n · ΔT
= K2 · (θ1 + n · Δθh) + (K1−K2) · θ1 (3)

  FIG. 4 shows how the steering reaction force command value Tp * is set when the steering angle θh increases by the minimum resolution Δθh. As shown in the figure, after the steering angle θh exceeds the angle θ1, the calculated steering reaction force command value Tp * is a value on the straight line B (second characteristic line) of the slope K2. Note that (K1−K2) · θ1 in the second term on the right side in Equation (3) is the intercept T0 of the straight line B in FIG.

  When the steering wheel 22 is turned back from the state where the steering angle θh is larger than the angle θ1, the steering reaction force command value Tp * is calculated by the following equation (5).

  Tp * = K1 · θh− (K1−K2) · (θ2−θ1) (5)

  The steering reaction force command value Tp * immediately before the determination of the switchback is the value of the point B2 on the straight line B in FIG. When the switchback is started, the steering reaction force command value Tp * is calculated by the equation (5), and the steering reaction force command value Tp * is a straight line A2 (first characteristic) of the slope K1 passing through the point B2 in FIG. Value on line). Then, the steering reaction force command value Tp * is calculated by the equation (5) until the steering angle θh is reduced by the angle required to reach the intersection D2 with the straight line D from the intersection B2 with the straight line B on the straight line A2. The As described above, when the steering reaction force command value Tp * with respect to the steering angle θh is on the second characteristic line (for example, the straight line B), the steering reaction force command is changed when the direction of the additional turning back of the handle 22 is changed. The value Tp * becomes a value on the first characteristic line (for example, the straight line A2), and the inclination of the steering reaction force command value Tp * with respect to the steering angle θh changes (increases) from K2 to K1. Here, the straight line B with the inclination K2 corresponds to the steering reaction force characteristic at the time of addition, and the straight line A2 with the inclination K1 corresponds to the steering reaction force characteristic for applying the steering reaction force corresponding to the Coulomb friction. By increasing the value of the slope K1, it is possible to obtain a hysteresis approximating Coulomb friction by a spring element having a high rigidity (spring constant).

  Next, consider a case where the steering angle θh is cut back to an angle θ3 corresponding to the intersection D2 between the straight line A2 and the straight line D in FIG. When further turning back is performed from this angle θ3, every time the steering angle θh is turned back by the minimum resolution Δθh, ΔT calculated by the above equation (2) is subtracted. That is, when the angle θ3 is switched back by m times the minimum resolution Δθh, the steering reaction force command value Tp * is calculated by the following equation (6).

  Tp * = − T0 + K2 · (θ3−m · Δθh) (6)

  FIG. 4 shows how the steering reaction force command value Tp * is set when the steering angle θh decreases by the minimum resolution Δθh. As shown in the drawing, after the steering angle θh is decreased from the angle θ3, the calculated steering reaction force command value Tp * becomes a value on the straight line D (second characteristic line) of the slope K2. Thus, when the steering reaction force command value Tp * with respect to the steering angle θh is on the first characteristic line (for example, the straight line A2), the steering angle θh is at the intersection of the first characteristic line and the second characteristic line. When the corresponding angle (for example, the angle θ3 corresponding to the intersection D2 of the straight line A2 and the straight line D) is reached, the steering reaction force command value Tp * becomes a value on the second characteristic line (for example, the straight line D), and the steering is performed. The inclination of the steering reaction force command value Tp * with respect to the angle θh changes (decreases) from K1 to K2. The straight line D with the inclination K2 here corresponds to the steering reaction force characteristic at the time of switching back. In the present embodiment, the steering reaction force command value Tp * is set based on the steering angle θh and the determination result of the additional turning back, whereby the current state in the hysteresis characteristic (the steering angle θh and the steering reaction force Tp are linear) It is possible to reproduce the hysteresis characteristic due to Coulomb friction that does not depend on the steering speed while accurately grasping the position (A, B, C, D).

  When the minimum resolution Δθh of the steering angle sensor 24 is not sufficiently high, self-excited vibration is likely to occur in the steering wheel 22, and when the level of the self-excited vibration increases, the driver feels uncomfortable and uncomfortable. In particular, self-excited vibration is likely to occur when the absolute value of the steering reaction force Tp is small, such as when the steering wheel 22 is released or when the steering wheel 22 is held lightly. Therefore, in the present embodiment, when the vibration level detected by the vibration level detection unit 64 is equal to or higher than a predetermined level, the steering reaction force command value calculation unit 66 sets the first characteristic line (for example, the characteristic lines A, A2, and A2). The inclination at C) (the inclination of the steering reaction force Tp with respect to the steering angle θh) is set to K3 smaller than K1. Thereby, the level of self-excited vibration of the handle 22 is suppressed. On the other hand, when the vibration level detected by the vibration level detection unit 64 is lower than the predetermined level, the steering reaction force command value calculation unit 66 sets the inclination of the first characteristic line to K1.

  As described above, the vibration level detector 64 detects the vibration level of the steering angle θh corresponding to the resonance frequency of the handle 22. When the steering reaction force command value Tp * with respect to the steering angle θh is on a first characteristic line (for example, straight lines A, A2, and C), the rigidity (spring constant) of the handle 22 is represented by an inclination K1. The resonance frequency (angular frequency) ω1 is expressed by the following equation (7). On the other hand, when the steering reaction force command value Tp * with respect to the steering angle θh is on the second characteristic line (for example, straight lines B and D), the rigidity of the handle 22 is represented by the inclination K2, and the resonance frequency (angle) of the handle 22 is expressed. (Frequency) ω2 is expressed by the following equation (8). In equations (7) and (8), Jh is the moment of inertia of the handle 22.

ω1 = (K1 / Jh) ^0.5 (7)
ω2 = (K2 / Jh) ^0.5 (8)

  As shown in equations (7) and (8), the resonance frequency of the handle 22 is determined based on the inclination K1 or the inclination K2. In order to detect the vibration level of the steering angle θh corresponding to the resonance frequency of the handle 22 with high accuracy, the vibration level detector 64 allows a frequency band including the resonance frequencies ω1 and ω2 of the handle 22 to pass (in ω1 and ω2). It is preferable to set the pass band in the band pass filter processing so that the corresponding frequency component is extracted.

  As shown in FIG. 5, when the steering angle θh is held at an angle θ4 slightly cut back from the angle θ2, a resonance phenomenon (self-excited vibration) corresponding to the inertia Jh and the rigidity K1 of the handle 22 occurs. Consider an example in which the vibration level detected by the vibration level detector 64 is equal to or higher than a predetermined level. In this case, the steering reaction force command value calculation unit 66 has an inclination in the first characteristic line A2 (an inclination of the steering reaction force Tp with respect to the steering angle θh) under the condition that the steering angle θh is within a setting range including the vibration center θ4. ) Is set to K3 smaller than K1. Thus, the minimum unit of the steering reaction force command value Tp * can be reduced from K1 · Δθh to K3 · Δθh, and the vibration level when vibration occurs in the handle 22 can be quickly suppressed. For example, as shown in FIG. 5, the setting range here is from θ4−Δθh (lower limit value) to θ4 + Δθh (upper limit value) that is plus or minus the minimum resolution Δθh of the steering angle sensor 24 with the operating point θ4 as the vibration center. It can be a range. On the other hand, when the steering angle θh is out of the setting range where θ4−Δθh is the lower limit and θ4 + Δθh is the upper limit, as shown in FIG. 5, the slope of the first characteristic line A2 is set to K1. As a result, it is possible to give the driver a feeling of friction due to Coulomb friction. Note that the vibration level detection unit 64 can detect the operating point (vibration center of the steering angle θh) θ4 based on, for example, a vibration waveform (time-series waveform) of the steering angle θh.

  Furthermore, when the steering wheel 22 is turned back from the state where the steering angle θh is the angle θ4, the steering angle θh is reduced by an angle required to reach the intersection D2 with the straight line D on the characteristic A2 (straight line of the inclination K1). Until then, the steering reaction force command value Tp * is calculated by the following equation (9). In Equation (9), T2 is a steering reaction force command value at an angle θ4 (see FIG. 5).

  Tp * = T2−K3 · Δθh−K1 · (θ4−θh−Δθh) (9)

When the driver releases the handle 22 when the steering angle θh is the angle θ4, the steering angle θh converges to the angle θ5 (see FIG. 5) according to the equation of motion of the handle 22 expressed by the following equation (10). However, since the inclination (rigidity) K1 of the steering reaction force Tp with respect to the steering angle θh is a large value, the handle 22 vibrates. In equation (10), dθh / dt is the steering angular velocity (time derivative of the steering angle θh), d ² θh / dt ² is the steering angular acceleration (time derivative of the steering angular velocity), and ch is the viscous friction coefficient of the handle 22. is there.

Jh · d ² θh / dt ² = K1 · (θh−θ5) −ch · dθh / dt (10)

  When the stiffness in the vicinity of the angle θ5 (the inclination of the steering reaction force Tp with respect to the steering angle θh) is set to K1, the minimum unit K1 · Δθh of the steering reaction force command value Tp * is large as shown in FIG. Thus, the steering angle θh causes hunting by the control, and the vibration of the handle 22 becomes difficult to attenuate. On the other hand, in the present embodiment, when the vibration level detected by the vibration level detection unit 64 is equal to or higher than a predetermined level, the rigidity in the vicinity of the operating point θ5 (for example, a range in which θ5-Δθh is the lower limit and θ5 + Δθh is the upper limit), That is, since the inclination of the steering reaction force Tp with respect to the steering angle θh is set to K3 smaller than K1, the minimum unit of the steering reaction force command value Tp * can be reduced to K3 · Δθh as shown in FIG. As a result, the vibration of the handle 22 can be quickly suppressed without causing the hunting by the control of the steering angle θh. Further, since the minimum unit of the steering reaction force command value Tp * is small, there is an effect that the torque fluctuation of the steering wheel 22 is not concerned even when the driver is touching the steering wheel 22. For this purpose, it is preferable to set the value of the slope K3 so that the torque fluctuation K3 · Δθh is smaller than the torque fluctuation that the driver can feel. Further, when the driver tries to steer and the arm muscles are in a certain tension state, the equivalent inertia in the direction of rotation of the handle increases, and the self-excited vibration of the handle 22 is attenuated. In the present embodiment, when the vibration level detected by the vibration level detector 64 is lower than a predetermined level, the rigidity around the operating point θ5 (the inclination of the steering reaction force Tp with respect to the steering angle θh) is set to K1, which is larger than K3. Therefore, the driver who operates the handle 22 can sufficiently feel the friction feeling due to Coulomb friction.

  As described above, according to this embodiment, it is possible to reproduce the hysteresis characteristic due to Coulomb friction that does not depend on the steering speed, and to quickly suppress the vibration level when self-excited vibration occurs in the handle 22. Can do. As a result, a good steering feeling can be obtained.

  In the above description, for easy explanation, the steering reaction force command value Tp * is calculated without considering the vehicle speed V. However, in the steering apparatus 20 according to the embodiment, the slope K1 of the characteristic lines A, A2, and C, the slope K2 of the characteristic lines B and D, and the intercepts T0 and -T0 in FIGS. As a result, the steering reaction force command value Tp * can be calculated.

  In the present embodiment, when the vibration level detected by the vibration level detection unit 64 is equal to or higher than a predetermined level, the steering reaction force command value calculation unit 66 changes the value of the inclination K3 according to the vibration level. You can also. For example, the value of the slope K3 can be reduced as the vibration level detected by the vibration level detector 64 increases. Thus, by reducing the value of the inclination K3 with respect to the increase in the vibration level detected by the vibration level detection unit 64, the vibration of the handle 22 can be quickly suppressed when the vibration level of the handle 22 is large. In addition, when the vibration level of the handle 22 is small, the driver can be given a sufficient feeling of friction due to Coulomb friction.

  In the above description, when the vibration level detected by the vibration level detection unit 64 is equal to or higher than the predetermined level, the value θ4-Δθh obtained by subtracting the minimum resolution Δθh from the vibration center of the steering angle (for example, θ4 in FIG. 5) is set to the lower limit. The slope of the first characteristic line (for example, characteristic lines A, A2, and C) is set to K3 within a range in which the upper limit is a value θ4 + Δθh obtained by adding the minimum resolution Δθh to the vibration center θ4 of the steering angle. However, in the present embodiment, when the vibration level detected by the vibration level detection unit 64 is equal to or higher than a predetermined level, the steering reaction force command value calculation unit 66 responds to the first characteristic line (for example, It is also possible to change the range of the steering angle θh that reduces the inclination of the characteristic lines A, A2, C) to K3. For example, the greater the vibration level detected by the vibration level detection unit 64, the wider the range of the steering angle θh that makes the inclination of the first characteristic line smaller to K3. As described above, the vibration level of the steering wheel 22 is also increased by increasing the range of the steering angle θh that reduces the inclination of the first characteristic line to K3 with respect to the increase of the vibration level detected by the vibration level detector 64. When it is large, the vibration of the handle 22 can be quickly suppressed, and when the vibration level of the handle 22 is small, a feeling of friction due to Coulomb friction can be sufficiently given to the driver.

  In the present embodiment, the vibration level detection unit 64 can also change the passband in the bandpass filter process. In this case, the steering reaction force command value calculation unit 66 determines that the steering reaction force command value Tp * with respect to the steering angle θh is based on the steering angle θh and the determination result of turning back / up of the steering wheel 22 as the first characteristic line. Whether it is on (for example, straight lines A, A2, C) or a second characteristic line (for example, straight lines B, D) is determined. And the vibration level detection part 64 changes the pass band in a band pass filter process according to this determination result. For example, when the steering reaction force command value Tp * with respect to the steering angle θh is on the first characteristic line, the vibration level detection unit 64 allows the frequency band including the resonance frequency ω1 of the handle 22 to pass (the frequency corresponding to ω1). The passband in the bandpass filter process is set so that the component is extracted. On the other hand, when the steering reaction force command value Tp * with respect to the steering angle θh is on the second characteristic line, the vibration level detection unit 64 passes the frequency band including the resonance frequency ω2 of the handle 22 (the frequency corresponding to ω2). The passband in the bandpass filter process is set so that the component is extracted. Thereby, the vibration level corresponding to the resonance frequency of the handle 22 can be detected with higher accuracy.

  In the steering device 20 according to the embodiment, the characteristic of drawing the parallelogram in FIG. 3 has been described as the hysteresis characteristic of the steering reaction force command value Tp *. However, the steering angle θh and the steering reaction force command value Tp * As long as hysteresis characteristics are obtained in the relationship, various shapes as illustrated in FIG. 8 may be drawn. Further, the slopes K1 and K2 in the hysteresis characteristic do not necessarily have to be constant values, and can be changed according to the steering angle θh.

  In the steering device 20 according to the embodiment, the reaction force motor 40 is driven and controlled based on the calculated steering reaction force command value Tp *. However, as shown in the control block illustrated in FIG. A value obtained by multiplying the steering angular velocity, which is a time derivative of θh, by a damper gain may be added to the steering reaction force command value Tp *, and the reaction force motor 40 may be driven and controlled based on this value. In this way, the convergence characteristic to the equilibrium point when the hand is released from the handle 22 can be improved.

  In the steering device 20 according to the embodiment, the steering reaction force is applied to the handle 22 by the torque of the reaction motor 40. However, the steering reaction force can be applied to the handle 22 using an actuator other than the motor.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to such embodiment at all, and it can implement with a various form in the range which does not deviate from the summary of this invention. Of course.

It is a figure showing a schematic structure of steering device 20 concerning an embodiment of the present invention. It is explanatory drawing which illustrates a control block when the electronic control unit 50 of the steering device 20 which concerns on embodiment of this invention operate | moves as the steering reaction force command value calculation block 60 which calculates steering reaction force command value Tp *. It is explanatory drawing which shows an example of the relationship between steering angle (theta) h and steering reaction force Tp. It is explanatory drawing explaining a mode that steering reaction force command value Tp * is calculated from steering angle (theta) h. It is explanatory drawing explaining a mode that steering reaction force command value Tp * is calculated from steering angle (theta) h. It is a figure which shows an example of the vibration characteristic of the handle | steering-wheel 22 when maintaining the inclination of a 1st characteristic line at K1. It is a figure which shows an example of the vibration characteristic of the handle | steering-wheel 22 in the steering apparatus 20 which concerns on embodiment of this invention. It is explanatory drawing which shows an example of the shape of the hysteresis characteristic of a modification. It is explanatory drawing which shows an example of the control block of a modification.

Explanation of symbols

  20 Steering device, 22 Handle, 24 Steering angle sensor, 26 Torque sensor, 30, 32 Steering wheel, 34 Reducer, 36 Rack, 40 Reaction force motor, 42 Steering motor, 50 Electronic control unit, 52 CPU, 54 ROM, 56 RAM, 58 Vehicle speed sensor, 60 Steering reaction force command value calculation block, 62 Increase / return switching determination unit, 64 Vibration level detection unit, 66 Steering reaction force command value calculation unit

Claims (10)

A vehicle-mounted steering device that outputs a steering reaction force according to the operation of the steering wheel,
Steering angle detection means for detecting the steering angle of the steering wheel;
An increase / return determination means for determining whether to increase or decrease the steering wheel based on the detected steering angle;
Vibration level calculating means for calculating the vibration level of the steering angle based on the detected steering angle;
Target steering reaction force setting means for setting a target steering reaction force with hysteresis characteristics based on the determination result by the increase / decrease / return determination means and the detected steering angle;
Steering reaction force output means for outputting a steering reaction force so that the set target steering reaction force is output;
With
The hysteresis characteristic is
A first characteristic in which the steering reaction force changes with a first inclination with respect to a change in the steering angle, and a steering reaction force with a second inclination smaller than the first inclination with respect to a change in the steering angle. A second characteristic;
When the steering reaction force with respect to the steering angle is on the second characteristic and the direction of the steering wheel is increased and turned back, the inclination of the steering reaction force with respect to the steering angle is changed from the second inclination to the first inclination. When the steering angle changes to an inclination and the steering reaction force with respect to the steering angle is on the first characteristic, the steering angle reaches an angle corresponding to the intersection of the first characteristic and the second characteristic. The inclination of the steering reaction force with respect to an angle is a characteristic that changes from the first inclination to the second inclination,
The target steering reaction force setting means, when the vibration level calculated by the vibration level calculation means is equal to or higher than a predetermined level, sets the inclination of the steering reaction force with respect to the steering angle in the first characteristic as the first inclination. A steering device that sets a smaller third tilt. The steering apparatus according to claim 1,
When the vibration level calculated by the vibration level calculation means is equal to or higher than the predetermined level, the target steering reaction force setting means has the condition that the steering angle is within a setting range including the vibration center. A steering device that sets the inclination of the steering reaction force with respect to the steering angle in the characteristic to the third inclination. The steering apparatus according to claim 2,
The steering angle detecting means is means for detecting the steering angle with a predetermined resolution Δθh,
The steering device is a steering device in which a value obtained by adding Δθh to the vibration center of the steering angle is an upper limit, and a value obtained by subtracting Δθh from the vibration center of the steering angle is a lower limit. The steering apparatus according to claim 2,
The target steering reaction force setting means changes the setting range according to the vibration level calculated by the vibration level calculation means. The steering apparatus according to claim 4, wherein
The target steering reaction force setting means increases the setting range with respect to an increase in the vibration level calculated by the vibration level calculation means. The steering apparatus according to any one of claims 1 to 5,
The target steering reaction force setting means changes the third inclination according to the vibration level calculated by the vibration level calculation means. The steering apparatus according to claim 6, wherein
The target steering reaction force setting means is a steering device that reduces the third inclination with respect to an increase in vibration level calculated by the vibration level calculation means. The steering apparatus according to any one of claims 1 to 7,
The vibration level calculation means performs a filtering process for passing a band including a resonance frequency of a handle determined based on the first inclination or the second inclination with respect to the steering angle detected by the steering angle detection means. A steering device that calculates the vibration level of the steering angle after going. The steering apparatus according to claim 8, wherein
The target steering reaction force setting means determines whether a steering reaction force with respect to a steering angle is on the first characteristic or the second characteristic;
The vibration level calculation means is a steering device that changes a pass band in the filter processing according to the determination result. A steering reaction force setting method for setting a steering reaction force according to an operation of a steering wheel of a vehicle,
Based on the steering angle of the steering wheel, it is determined whether the steering wheel is increased or not,
In a steering reaction force setting method for setting a steering reaction force with hysteresis characteristics based on the determination result and the steering angle of the steering wheel,
The hysteresis characteristic is
A first characteristic in which the steering reaction force changes with a first inclination with respect to a change in the steering angle, and a steering reaction force with a second inclination smaller than the first inclination with respect to a change in the steering angle. A second characteristic;
When the steering reaction force with respect to the steering angle is on the second characteristic and the direction of the steering wheel is increased and turned back, the inclination of the steering reaction force with respect to the steering angle is changed from the second inclination to the first inclination. When the steering angle changes to an inclination and the steering reaction force with respect to the steering angle is on the first characteristic, the steering angle reaches an angle corresponding to the intersection of the first characteristic and the second characteristic. The inclination of the steering reaction force with respect to an angle is a characteristic that changes from the first inclination to the second inclination,
When setting the steering reaction force, the vibration level of the steering angle is calculated based on the steering angle of the steering wheel,
When the calculated vibration level is equal to or higher than a predetermined level, a steering reaction force setting method for setting the inclination of the steering reaction force with respect to the steering angle in the first characteristic to a third inclination smaller than the first inclination. .

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