JP3518590B2 - Vehicle steering control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle steering control device having a transmission ratio variable mechanism for changing a transmission ratio between a steering angle of a steering wheel and a steered angle of steered wheels.

[0002]

2. Description of the Related Art Conventionally, there has been known a vehicle steering control device provided with a transmission ratio variable mechanism for changing a transmission ratio between a steering angle of a steering wheel and a steering angle of steered wheels. For example,
Japanese Unexamined Patent Publication No. 6-227422 discloses a device that controls an actuator that drives a transmission ratio variable mechanism according to a steering angle of a steering wheel, based on a transmission ratio set according to a vehicle speed.

[0003]

The drive control of the actuator in such a transmission ratio variable mechanism is performed based on the steering angle of the steering wheel, the rotation angle of the output shaft of the transmission ratio variable mechanism, the operating angle of the actuator, and the like. As a matter of fact, as the sensor for detecting the steering angle or the like, a relative angle sensor for detecting the relative displacement may be adopted due to the simplicity of the configuration, the manufacturing cost and the like. For example, as an example of the structure of the steering angle sensor, it is configured by a rotary encoder that rotates together with the steering shaft, and by counting the two-phase pulse signals output from this rotary encoder,
It is a mechanism that detects the relative rotation angle of the steering wheel. Thus, it is possible to use the relative angle sensor and perform the steering control based on the detection result of the relative angle sensor. However, if the absolute angle of the detection target can be grasped from the start of the control, the suitable steering control can be immediately performed. Can be performed.

The present invention has been made to solve such a problem, and an object thereof is to use a relative angle sensor and an absolute angle sensor as a detection sensor in combination for control, which is more preferable than when starting control. It is an object of the present invention to provide a vehicle steering control device capable of performing steering control.

[0005]

According to a first aspect of the present invention, there is provided a vehicle steering control device including a transmission ratio variable mechanism for changing a transmission ratio between a steering angle of a steering wheel and a steering angle of steered wheels. A steering control device for vehicle, comprising: a steering angle detecting means for detecting a steering angle of a steering wheel by a relative angle; a driving means for rotationally driving a transmission ratio variable mechanism; and an operating angle for detecting an operating angle of the driving means by an absolute angle. The control unit includes a detection unit, a control unit that controls the drive of the drive unit based on the transmission ratio set according to the traveling state, and the steering angle detected by the steering angle detection unit. An estimation means for estimating the absolute steering angle of the steering wheel is provided based on the detection result of the operating angle detection means and the transmission ratio set in the transmission ratio variable mechanism.

The steered angle of the steered wheels is the sum of the steered angle of the operated steering wheel and the operating angle of the variable transmission ratio mechanism which is rotationally driven by the drive means. Further, at that time, the steering angle of the operated steering wheel is transmitted as the steering angle of the steered wheels under the transmission ratio set in the transmission ratio variable mechanism. Therefore, the estimating means detects the operating angle of the driving means as an absolute angle based on these relationships, and based on the detected operating angle and the transmission ratio at that time, the steering angle of the steering wheel is calculated as an absolute angle. Estimate as.

A vehicle steering control device according to claim 2 is
A steering control device for a vehicle, comprising a transmission ratio variable mechanism for changing a transmission ratio between a steering angle of a steering wheel and a steered angle of steered wheels, comprising: a drive unit for rotationally driving the transmission ratio variable mechanism; An operating angle detecting means for detecting an operating angle of the means, and a lock means for setting a lock position for prohibiting the variable operation of the transmission ratio in the variable transmission ratio mechanism at each angular pitch A (A> 0) are provided. The operating angle detecting means is a means for detecting the operating angle of the driving means in units of angular pitch B (B> 0), and the relationship between the angular pitches A and B is B <A <2B. .

Even when the position where the locking means is operated and the lock position where the transmission ratio variable mechanism is actually locked deviate by one angular pitch A, the relationship between the angular pitches A and B becomes
By setting B <A <2B, it becomes possible to reliably detect this shift amount by the operating angle detection means.

A vehicle steering control device according to claim 3 is
A steering control device for a vehicle, comprising a transmission ratio variable mechanism for changing a transmission ratio between a steering angle of a steering wheel and a steering angle of steered wheels, comprising steering angle detection means for detecting a steering angle of a steering wheel. Drive means for rotationally driving the variable transmission ratio mechanism,
Control for performing drive control of the drive means based on the operation angle detection means for detecting the operation angle of the drive means, the transmission ratio set according to the traveling state, and the steering angle detected by the steering angle detection means. The steering angle detecting means and the operating angle detecting means, one of which is configured as a relative angle detecting means for detecting a relative angle, and the other is configured as an absolute angle detecting means for detecting an absolute angle. The angle deviation generated between the absolute angle detected by the absolute angle detection means at the end of control and the absolute angle detected by the absolute angle detection means after the control is restarted is reduced in accordance with the steering operation of the steering wheel. The drive control of the drive means is performed.

It should be noted that "after the control is restarted" is meant to include the start of the restarted control.

When there is an angular deviation between the absolute angles detected by the absolute angle detecting means at the end of control and after the control is restarted, if the driving means is driven immediately to eliminate the angular deviation, the steering wheel is turned. Alternatively, the steered wheels may be displaced and driven, which may give the driver a feeling of strange steering. Therefore, in such a case, the control means allows the detected angular deviation to remain, and controls the driving of the driving means so that the angular deviation gradually decreases with the steering operation of the steering wheel.

A vehicle steering control device according to a fourth aspect of the present invention is
A steering control device for a vehicle, comprising a transmission ratio variable mechanism for changing a transmission ratio between a steering angle of a steering wheel and a steering angle of steered wheels, comprising steering angle detection means for detecting a steering angle of a steering wheel. Drive means for rotationally driving the variable transmission ratio mechanism,
The operating angle detecting means for detecting the operating angle of the drive means, the turning angle detecting means for detecting the turning angle of the steered wheels, the transmission ratio set according to the traveling state, and the steering angle detecting means The steering angle detection means and the operation angle detection means, one of which is a relative angle detection means for detecting a relative angle, and the other is an absolute angle. The control means is configured as an absolute angle detecting means for detecting an angle, and the control means includes a turning angle detected by the turning angle detecting means, a steering angle detected by the steering angle detecting means, and an operating angle detected by the operating angle detecting means. Based on the above, it further comprises a determination means for determining a failure of the relative angle detection means.

Since the relative angle detecting means detects the angle based on the relative change from the previous detection result, if the previous detection memory is lost or the detection target is skipped, etc. Reduces the reliability of the detection result. Further, the amount obtained by adding the angle corresponding to the operating angle of the driving means to the steering angle becomes the steering angle. Therefore, the determining means determines the steering angle detecting means and the operating angle detecting means based on this relationship. A failure of the relative angle detecting means when one of the two is used as the relative angle detecting means is determined.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.
Description will be given with reference to the accompanying drawings.

FIG. 1 shows the configuration of the steering system according to the first embodiment.

The input shaft 20 and the output shaft 40 are connected via a variable transmission ratio mechanism 100, and the steering handle 10 is connected to the input shaft 20. The output shaft 40 is connected to a rack shaft 51 via a rack and pinion type gear device 50.
Wheels FL and FR as steered wheels are connected to both sides of the rack shaft 51.

Further, since the steering angle of the steering wheel 10 corresponds to the rotation angle of the input shaft 20, the input shaft 20 is provided with an input angle sensor 21 for detecting the input angle θh as the rotation angle of the input shaft 20, The output shaft 40 is provided with an output angle sensor 41 that detects an output angle θp as a rotation angle of the output shaft 40. The input angle sensor 21 and the output angle sensor 41 are
The rotary encoder is configured to detect a relative displacement angle, and a two-phase pulse signal output from the rotary encoder is given to a steering control device 70 described later.
The rotation direction of the steering wheel 10 is detected based on the phase difference between the two-phase pulse signals, and the relative rotation angle of the steering wheel 10 is detected by counting the number of pulses.

Since the rotation angle of the output shaft 40 corresponds to the stroke position of the rack shaft 51, and the stroke position of the rack shaft 51 corresponds to the turning angles of the wheels FL and FR, the output angle sensor 41 outputs the rotation angle. By detecting the rotation angle of the shaft 40, the steering angles of the wheels FL and FR are detected.

The variable transmission ratio mechanism 100 connects the input shaft 20 and the output shaft 40 via a predetermined gear mechanism for connecting the input shaft 20 and the output shaft 40.
The gear mechanism is driven by an actuator 110 composed of, for example, a servo motor, so that the transmission ratio between the steering angle of the steering wheel 10 and the turning angles of the wheels FL and FR is changed. The actuator 110 is provided with an operating angle sensor 131 that detects the operating angle of the actuator 110 by an absolute angle (absolute operating angle), and the detected operating angle θm is given to the steering control device 70. The actuator 110 has a mechanism that is locked after the control is completed by turning off the ignition switch, and the operating angle of the actuator 110 does not change before the ignition switch is turned on. Absent.

The drive control of the variable transmission ratio mechanism 100 is carried out by the steering control device 70. The steering control device 70 includes an input angle sensor 21, an output angle sensor 41, an operating angle sensor 131, a vehicle speed sensor 60 for detecting the vehicle speed,
Wheel speed sensor 61 for detecting the rotational speeds of the wheels FL, FR
Of each of the detection signals, the transmission ratio G is set based on these signals, the control current Is is output to the actuator 110, and the control current Is is transmitted according to the input angle θh that is the steering angle of the steering wheel 10. The drive control of the ratio variable mechanism 100 is performed.

The control process executed by the steering control device 70 will be described below with reference to the flow chart of FIG.

This flowchart is started by turning on the ignition switch. First, the process proceeds to step (hereinafter referred to as “S”) 102, and the working angle θmo of the actuator 110 stored in the memory is read. The operating angle θmo is, as will be described later,
It is an operating angle indicating the absolute rotational position of the actuator 110 stored when the ignition switch is turned off.

In subsequent S104, the absolute angles of the input shaft 20 and the output shaft 40 at the start of control are estimated based on the operating angle θmo of the actuator 110 read in S102. If the transmission ratio is G, the input angle θh and the output angle θp
The relationship between and is θp = G · θh. Further, since the actuator 110 rotates by the operating angle θm, the input angle θ
Since h is accelerated to the output angle θp, θp = θh + θ
Suppose that the relationship is m.

From these relationships, the input angle θh and the output angle θp are expressed by the transmission ratio G and the operating angle θm, respectively, and the following equations (1) and (2) are obtained.

Θh = θm / (G−1) (1) θp = G · θm / (G−1) (2) The operating angle of the actuator 110 when the ignition switch is turned off is θmo. When vehicle speed V
= 0, the vehicle speed V =
The transmission ratio at 0 is Go. Therefore, when the absolute angle of the input shaft 20 at the start of control is θho and the absolute angle of the output shaft 40 is θpo, the equations (1) and (2) can be expressed by the following equations (3) and (4). .

Θho = θmo / (Go−1) (3) θpo = Go · θmo / (Go−1) (4) Thus, the absolute angle θ of the input shaft 20 at the start of control
ho and the absolute angle θpo of the output shaft 40 are the actuator 1
It can be estimated based on the operating angle θmo of 10 and the transmission ratio Go.

At S106, the input angle θh detected by the input angle sensor 21, the output angle θp detected by the output angle sensor 41, and the vehicle speed V detected by the vehicle speed sensor 60 are read. As described above, the input angle sensor 21 and the output angle sensor 41 are sensors that detect relative rotation angles, and are detected as relative displacement angles from the absolute angles θho and θpo estimated in S104.

In subsequent S108, the map showing the relationship between the vehicle speed V and the transmission ratio G shown in FIG. 3 is searched based on the vehicle speed V read in S106, and the transmission ratio G corresponding to the vehicle speed V is set. .

In subsequent S110, θpm = G · θh is calculated based on the transmission ratio G set in S108 and the input angle θh read in S106 to set the output angle target value θpm.

In subsequent S112, a deviation e between the output angle target value θpm set in S110 and the output angle θp detected by the output angle sensor 41 is calculated as e = θpm−θp.

In subsequent S114, the actuator 11 is controlled so that the deviation e is set to 0 without overshooting.
A control current Is for controlling 0 is determined. As an example of this process, based on the arithmetic expression of Is = C (s) · e, P
The control current Is can be determined by appropriately setting the ID control parameter. In addition, "(s)" in a formula is a Laplace operator.

In subsequent S116, the control current Is determined in S114 is output to the actuator 110, and the actuator 110 is driven based on the control signal Is.

After that, the process proceeds to S118, it is determined whether the ignition switch (IG) is turned off, and "No" is determined.
In the case of, the process returns to S106, and the above-described processing of S106 and thereafter is repeatedly executed until it is determined to be “Yes” in S118.

When the ignition switch is turned off, it is determined to be "Yes" in S118, the process proceeds to S120, the operating angle θm of the actuator 110 detected by the operating angle sensor 131 at this time is read, and the subsequent S12 is performed.
In 2, the read operating angle θm is θmo,
It is stored in the memory in the steering control device 70.

By repeating such processing, the rotation angles of the input angle θh and the output angle θp can be grasped at the start of the steering control. Based on this result, the wheels FL corresponding to the input angle θh and the vehicle speed V, It becomes possible to immediately start suitable steering control of the FR.

Next, a second embodiment will be described.

The control processing according to the second embodiment is shown in FIG.
A description will be given according to the flowchart in FIG. It should be noted that the same processing steps as those in the flowchart of FIG.

After turning on the ignition switch, S
102 to S106 are similarly executed, and thereafter, S202
Proceed to.

In S202, it is determined whether the correction flag F indicating that the correction processing of the input angle θh has been executed is reset to 0. Since the correction flag F is reset at the time of start-up, immediately after the start-up, it is determined as “Yes” and S20.
Go to 4.

In S204, it is determined whether or not the vehicle speed V is higher than the threshold value Vth. If the vehicle speed V is equal to or lower than the threshold value Vth, it is determined as "No". The process is executed.

When the vehicle speed V becomes higher than the threshold value Vth after the start of traveling, it is determined to be "Yes" in S204 and the routine proceeds to S206, where the left and right wheel speeds VWFL detected by the wheel speed sensor 61, Read VWFR.

In subsequent S208, the output angle θphat which is the rotation angle of the output shaft 40 is estimated based on the read left and right wheel speeds VWFL and VWFR. Specifically, assuming that the transmission ratio being set is G, the wheelbase of the vehicle is L, and the tread is W, the output angle θphat can be estimated based on the following equation (5).

Θphat = (2 · G · L / W) · (VWFL−VWFR) / (VWFL + VWFR) (5) If there is a deviation between the estimated output angle θphat and the detected θp, it is detected. This means that the value of the input angle θh is deviated from the absolute angle by the angle calculated by (θphat−θp) / G. Therefore, in subsequent S210, the calculation result of θh− (θphat−θp) / G is newly set as the input angle θh.

In subsequent S212, a correction flag F indicating that the correction processing of the input angle θh has been executed is set to 1,
Then, the process proceeds to S108 and the subsequent steps.

Since the correction flag F is set to 1 in this way, in the next routine, S106 is executed and then S is executed.
Since the processing proceeds to 202 and is determined to be “No” in S202 and proceeds to S108, the correction processing of S204 to S212 is not repeatedly executed.

By executing the processing of S202 to S212 as described above, the absolute angle θho of the input shaft 20 estimated in S104 is estimated for some reason, for example, the steering wheel is operated after the ignition switch is turned off. Can be dealt with even when is deviated from the regular absolute angle, and the absolute angle of the input angle θh can be grasped by such a correction process.

In each of the embodiments described above, the actuator 110 when the ignition switch is turned off.
The operating angle θm of the actuator 110 is stored, but the operating angle θm of the actuator 110 is detected when the ignition switch is turned on, and the expressions (3) and (4) are used based on the detection result and the transmission ratio Go. It is also possible to estimate the absolute angles θho and θpo.

Further, in the flow chart shown in FIG. 4, when the correction condition is satisfied, the correction processing of the input angle θh is as follows:
Although the case where the deviation calculated by (θphat−θp) / G is corrected at one time has been exemplified, for example, 1 / N of this deviation is corrected for each correction process and the routine is repeated N times. It is also possible to gradually correct the input angle θh such as ending the correction process, and thus it is possible to prevent a sudden change in the turning angles of the wheels FL and FR during the correction.

Further, the case where the transmission ratio of the transmission ratio variable mechanism 100 is set according to the vehicle speed V has been exemplified, but it may be set according to the running state of the vehicle, such as based on the vehicle speed V and the input angle θh. Is.

Next, a third embodiment will be described.

FIG. 5 shows an example of the transmission ratio variable mechanism 100. In the drawings shown below, the same components as those shown in FIG. 1 are designated by the same reference numerals.

The variable transmission ratio mechanism 100 has a cylindrical housing 101. A stator 111 is fixed to the inside of the cylindrical surface of the housing 101, and a rotor 112 integrated with a hollow shaft 113 is provided inside the stator 111. The stator 110 and the rotor 112 constitute the actuator 110. The actuator 110 is, for example, a brushless motor having two magnetic poles.

The hollow shaft 113 is the wave gear reducer 1
It is integrated with the elliptical cam 121 that forms part 20 and has a structure in which the movable flange 122 rotates relative to the housing 101 by rotationally driving the elliptical cam 121 by the actuator 110. The input shaft 20 is fixed to the movable flange 122, and the housing 1
Since the output shaft 40 is fixed to 01, the input shaft 20 and the output shaft 40 are relatively rotated by rotationally driving the actuator 110. This action is a mechanism for changing the transmission ratio of the rotation amount between the input shaft 20 and the output shaft 40, and the transmission ratio is variably controlled by controlling the rotation of the actuator 110.

As shown in FIG. 6, on the outer peripheral portion of the hollow shaft 113, an N pole 130N and an S pole 13 are formed in a semicircular arc shape.
Since the ring-shaped magnet 130 with 0S is fixed and the number of magnetic poles of the actuator 110 is 2, the N pole 130N and the S pole 130S have a width of 180 °. Further, three operating angle sensors 131 are arranged at a pitch of 120 ° at positions facing the magnet 130 and fixed to the housing 101. The operating angle sensor 131 is composed of a Hall IC, and the Hall I
The rotation amount of the actuator 110 is detected by detecting the magnetic pole change by C.

Further, in the housing 101, there is provided a lock mechanism that prevents relative rotation between the rotor 112 and the stator 111 and prohibits variable transmission ratio operation when a failure occurs in the transmission ratio variable mechanism 100. ing.

As shown in FIG. 7, this lock mechanism is provided with a lock arm 140 curved in an arc shape, and a lock holder 114 around which concave and convex grooves having a convex portion forming pitch of 90 ° are formed. The lock arm 140 tilts around a support shaft 141 fixed to the housing 101 side, and the lock holder 114 is formed integrally with the hollow shaft 113 at the end of the hollow shaft 113.

The lock arm 140 is provided with a convex portion 140a, and by locking the convex portion 140a of the lock arm 140 in the concave portion of the lock holder 114, the rotor 1
12 is in a locked state in which relative rotation between the stator 12 and the stator 111 is prohibited.

The drive mechanism of the lock arm 140 is as follows. A drive coil 142 is provided at the tip of the lock arm 140, and a magnet 143 is fixed to the housing 101 side facing the drive coil 142. Although not shown, a coil spring is provided on the support shaft 141 of the lock arm 140, and the lock arm 140 constantly presses the lock arm 140 so as to incline toward the lock holder 114 side. Then, when the ignition switch is turned on, a current flows through the drive coil 142, so that a repulsive force due to an electromagnetic force is generated between the drive coil 142 and the magnet 143, and the lock arm is resisted against the pressing force of the coil spring. 140 is tilted in the direction away from the lock holder 114 and the lock is released.
Further, when the ignition switch is turned off or a failure occurs, the energization of the drive coil 142 is stopped and the repulsive force disappears. Therefore, the lock arm 140 tilts due to the pressing force of the coil spring, as shown in FIG. Return to the proper locked state.

Here, a method for detecting the working angle of the actuator 110 by the working angle sensor 131 will be described. FIG. 8 shows the detection signals of the three working angle sensors 131 as u, v, and w in the order of arrangement of the working angle sensors 131. For example, when the operating angle sensor 131 detects the N pole 130N of the magnet 130, 1 (High)
Level), 0 (Low) when the S pole 130S is detected
Assuming that the level signal is output, the detection signal of each operating angle sensor 131 changes as shown in FIG. That is, the magnetic pattern (u, v, w) that is the detection result of each operating angle sensor 131 is the rotor 112 and the stator 11
If the relative rotation with 1 is the same direction, the relative rotation angle is 60 °
, (1, 0, 0), (1, 1, 0), ... Therefore, the detection mechanism illustrated here detects the operating angle of the actuator 110 in units of an angular pitch of 60 °. Note that the magnetic pattern (u, v, w) changes in a 360 ° cycle, as can be seen from the transition of the numerical value P obtained by weighting and adding 2 ^{2 to} u, 2 ^{1 to} v, and 2 ⁰ to w. However, the relative rotation angle of the rotor 112 can be grasped from the magnetic pattern (u, v, w) or the number of changing pitches of the count value P.

As described above, the magnetic patterns (u, v, w) detected by the respective working angle sensors 131 regularly change in accordance with the relative rotation between the rotor 112 and the stator 111, so that the working angle of the actuator 110 is increased. If θm can be grasped, the operating angle θm of the actuator 110 after rotation can be grasped based on the magnetic pattern (u, v, w) or the change pitch number of the numerical value P, and based on this result. The absolute angle between the input angle θh and the output angle θp can be estimated.

An example of steering control using the detection result of the operating angle sensor 131 will be described below with reference to the flowchart of FIG. It should be noted that the same processing steps as those in the flowchart of FIG.

In S302, the operating angle θmo1 and the magnetic pattern (u, u of the actuator 110 when the ignition switch is turned off, which is stored in S316 to be described later.
Read the numerical value Po of v, w).

In the following S304, at this time, the magnetic pattern (u, v,
Read the numerical value Px of w).

By turning off the ignition switch,
Since the lock mechanism that locks the variable transmission ratio mechanism operates, the meter value Po and the meter value Px usually match. However, when the lock mechanism is activated, the lock holder 11 and the lock arm 140 are in a positional relationship, and therefore, the lock holder 11
The convex portion 1 of the lock arm 140 corresponds to the convex portion of the concave and convex groove 4
The locking operation may stop in the state where the 40a is in contact. In such a state, when the steering handle 10 is operated between the turning-off operation and the turning-on operation of the ignition switch, the lock holder 114 rotates according to the operation direction, and the lock holder 114 is positioned adjacent to the rotation direction. Inside the recess of the lock holder 114, the protrusion 14 of the lock arm 140
0a is locked, and the lock state is normal. In order to grasp such a situation, in S304, the meter value Px of the magnetic pattern (u, v, w) at the start of control is detected.

In subsequent S306, the numerical value Po of the magnetic pattern (u, v, w) read in S302 and S304
A map search is performed based on the deviation (Po-Px) from the measured value Px of the magnetic pattern (u, v, w) detected in 1. to set the change pitch number ΔP of the magnetic pattern.

In the following S308, based on the change pitch number ΔP of the magnetic pattern (u, v, w) set in S306 and the detection angle pitch of 60 ° of the working angle sensor 131, S308 is performed.
The operating angle θm of the actuator 110 read by 302
The angle correction value θx for o1 is calculated as θx = 60 ° · ΔP.

In subsequent S310, the working angle θmo1 of the actuator 110 read in S302 is corrected in consideration of the angle correction value θx calculated in S308. That is, the operating angle θmo of the actuator 110 is θmo = θ
Newly set as mo1 + θx.

After that, the processing shifts to S104 to S118 described in the flowchart of FIG. 2, and in S104, the operating angle θmo of the actuator 110 set in S310 is calculated from the equations (3) and (4) shown above. Based on, the absolute angle θho of the input shaft 20 and the output shaft 40 at the start of control
Estimate the absolute angle θ po of.

Then, the process proceeds to S118 and S11
The processes of S106 to S118 are repeatedly executed until it is determined in the determination of 8 that the ignition switch (IG) is turned off.

If it is determined in S118 that "Yes", that is, if the ignition switch (IG) is turned off, the process proceeds to S314, and the operating angle θm and the magnetic pattern (u, v) of the actuator 110 detected at this time are detected. , W) is read.

In subsequent S316, the operating angle θm read in S314 is stored as θmo1, and at the same time, S314.
The numerical value P read in step 3 is stored as Po to prepare for the next startup.

In order to carry out the correction processing in S302 to S310 in this way, it is necessary to be able to detect the deviation of the operating angle θm that may occur after the ignition switch is turned off. Taking the lock mechanism shown in FIG. 7 as an example, the groove pitch of the concave and convex grooves of the lock holder 114 defines the angular pitch of the lock position. The angular pitch of the lock position (groove pitch of the concave and convex grooves) is A, and the operating angle is When the angular pitch that can be detected by the sensor 131 is B, the relationship between the angular pitches A and B is set to B <A <2B, so that even if the lock position deviates by one angular pitch A, this misalignment Can be reliably detected by the operating angle sensor 131.

In the third embodiment, the number of magnetic poles of the brushless motor constituting the actuator 110 is exemplified as 2. However, even when the number of magnetic poles other than the two magnetic poles is set, the angular pitch of the lock position ( The groove pitch A of the concave and convex grooves can be set. That is, the number of magnetic poles of the motor is n, and the number of operating angle sensors 131 provided is u, v, w.
Assuming that there are three, the angular pitch B that can be detected by the operating angle sensor 131 is B = 360 / (3 · n).
Therefore, the angular pitch of the lock position (groove pitch of the concave and convex grooves)
A is 360 / (3 · n) <A <{360 / (3 ·
n)} · 2 may be set.

Next, a fourth embodiment will be described.

In the flowchart of FIG. 4 described as the second embodiment, the control target value of the output angle θp is set as the output angle target value θpm, and the output angle target value θpm and the output angle θ are set.
Although the drive control of the actuator 110 is performed according to the deviation from p, the drive control of the actuator 110 can also be performed based on the control deviation related to the operating angle θm of the actuator 110. The flow chart of FIG. 4 is rewritten in a form corresponding to this processing and shown in FIG.

In S104 of FIG. 10, the process of estimating the absolute angle θpo of the output shaft 40 is unnecessary as compared with S104 of FIG. 4, and in S106 of FIG. 10, instead of the output angle θp of S106 of FIG. The operating angle θm of 110 is read. Further, in S110 of FIG. 10, the control target is set as the operating angle target value θmm of the actuator 110 according to the above-described equation (1), and in the subsequent S112, the deviation e that is the control deviation is set to the operating angle set in S110. It is set as the difference between the target value θmm and the operating angle θm read in S106. Since θp = θh + θm, in S210 of FIG. 10, instead of θp of FIG. 4, (θh + θ
m) is used. The other control processes in the flowchart of FIG. 10 are the same as those in FIG.

When the control processing is carried out as shown in FIG. 10, as shown in FIG. 11, S208 and S210 of FIG.
The failure determination processing S400 can be performed between and. This failure determination process is a process of determining a failure of the sensor that detects the relative rotation angle, and corresponds to the input angle sensor 21 in the example of FIG.

FIG. 12 shows the failure determination process. First, S4
02, based on the input angle θh and the operating angle θm read in S106, the output angle θphat estimated in S208, and a predetermined threshold value Δth, | (θh + θm) −θphat | <
It is determined whether Δth. As mentioned above, (θh + θ
Since m) = θp, in S402, the output angle θp obtained from the relationship between the input angle θh and the operating angle θm, and S208
It is determined whether the deviation from the output angle θphat estimated in step 3 is smaller than the threshold value Δth.

In the case of "Yes" in S402, the output angle θp obtained from the relationship between the input angle θh and the operating angle θm,
It is determined that the output angle θphat estimated in S208 substantially matches, and the process proceeds to S210 and subsequent steps.

On the other hand, "No" in S402, that is, the output angle θp obtained from the relationship between the input angle θh and the operating angle θm.
If the deviation from the output angle θphat estimated in S208 is equal to or larger than the threshold value Δth, it means that either the detected value or the estimated value includes a large error. In this case, the operating angle θm is the rotation angle of the actuator 110 that constitutes the servo mechanism, and the output angle θphat is the angle estimated based on the left and right wheel speeds, and both are highly reliable.
On the other hand, since the input angle sensor 21 is a relative angle sensor and detects the angle based on the relative change from the previous detection result, the previous detection memory is lost, or the detection part is skipped. Can occur. Furthermore, since the transmission ratio control is performed based on the input angle θh, it is difficult to continue the steering control as it is when the reliability of the detection result of the input angle sensor 21 is low. From these, when it is determined to be "No" in S402, it can be determined that the reliability of the detection result of the input angle sensor 21 is low, and in this case, it is determined that the input angle sensor 21 has a failure. , S
Proceeding to 404, the failure indicator lamp is turned on to inform the driver that a failure has occurred. Then, in subsequent S406, the entire steering control thereafter is prohibited, and this routine is ended.

In the fourth embodiment, the input angle sensor 2
1 has been described as the relative angle sensor, the operating angle sensor 13
Even when 1 is configured as a relative angle sensor and the input angle sensor 21 is configured as an absolute angle sensor, the same failure determination process can be performed in S400. In this case, it is possible to determine whether or not there is a failure in the operating angle sensor 131. Will be judged.

Next, a fifth embodiment will be described.

FIG. 13 shows the control processing according to the fifth embodiment.
It is shown in the flowchart. The flow chart is started by turning on the ignition switch, and the input angle sensor 21 is an absolute angle sensor and the operation angle sensor 131 is a relative angle sensor.

First, in S502, the steering control device 70
The input angle θho stored in the internal memory is read. It should be noted that this input angle θho is, as described later, the input angle sensor 21 stored when the ignition switch is turned off.
Is the detection result of.

In the following S504, the input angle θh detected by the input angle sensor 21 is read at the time when the ignition switch is turned on, and in the following S506, the S
Based on the input angle θho read in 502 and the input angle θh read in S504, (θh−θho) is calculated,
The result is set as the first correction value Δθh. The first correction value Δθh indicates the steering angle of the steering wheel 10 that is displaced after the ignition switch is turned off until it is turned on.

In the following S508, the second correction value S set in the setting process described later is read. The specific setting process will be described later.

At S510, based on the input angle θh read at S504, the first correction value Δθh set at S506, and the second correction value S read at S508, θh is obtained.
-(Δθh-S) is calculated, and the result is newly input as the input angle θ.
Set as h. By this processing, the value of the input angle θh read in S504 is updated. Referring to the arithmetic expression of S510, the first correction value Δθh acts so as to allow the deviation between the input angle θho and the input angle θh to remain, and the second correction value S reduces the remaining deviation. Acts like. The initial value of the second correction value S is S = 0, and S
Since the input angle θh = θho is set by 510,
At the time of restarting control, the input angle θh is the input angle θ at the end of control.
Treated as unchanged from ho.

In the following S512, the operating angle θm detected by the operating angle sensor 131 and the vehicle speed V detected by the vehicle speed sensor 60 are read, and the following S514 to S522 are executed.
The same processing as S108 to S116 in FIG. 10 described above is performed, and the process proceeds to S524.

In S524, the value of the first correction value Δθh is set to
The value is updated by using the value obtained by subtracting the second correction value S from the first correction value Δθh. This sets the first correction value Δθh in S506 as a value indicating the initial deviation of the input angle θh.
Since the initial deviation is reduced by the second correction value S by a series of processes, in S524, the value of the remaining initial deviation is newly set as the first correction value Δθh.

While the ignition switch is on,
In the next step S526, it is determined to be "No" and the process proceeds to step S528.
The input angle θh that is the detection result of the input angle sensor 21 is newly read, and the processing from S508 is repeatedly executed.
Then, when the ignition switch is turned off, S
When it is determined to be “Yes” at 526, the process proceeds to S530, where the input angle θh detected by the input angle sensor 21 is θh.
It is stored in the memory as o and the steering control is ended.

Now, the process of setting the above-mentioned second correction value S will be described with reference to the flowchart of FIG.

First, in S602, it is determined whether or not the value of the first correction value Δθh has been updated in S524 of FIG. 13, and when updated (“Yes” in S602), the process proceeds to S604.

In S604, the updated first correction value Δθ
It is determined whether h = 0, that is, whether the initial deviation has been eliminated. In the case of “Yes” in this determination, the process proceeds to S606, the second correction value S = 0 is set, and the setting process of the second correction value S is ended.

On the other hand, if the first correction value Δθh ≠ 0 (“No” in S604), that is, if the initial deviation remains, the process proceeds to S608 and the steering speed dθh / d shown in FIG.
From the map showing the relationship between t and the second correction value S, a map search is performed based on the steering speed dθh / dt, and the second correction value S that decreases the first correction value | Δθh |
Is set according to the steering speed dθh / dt.

When such a correction process is continued, the first correction value | Δθh | gradually becomes the initial deviation of the input angle θh.
Changes so that the first correction value Δθh increases in S604.
= 0, that is, when it is determined that the initial deviation has been eliminated, the process proceeds to S606 as described above, the second correction value S = 0 is set, and the setting process of the second correction value S is ended.

In the illustrated map shown in FIG. 15, the second correction value S increases as the absolute value of the steering speed dθh / dt increases.
Is set to a large absolute value, and the steering speed dθh / d
In the steering holding state where t = 0, the second correction value S = 0 is set. As a result, the correction of the initial deviation is small at the time of slow steering, the correction is made larger as the steering is faster, and the correction processing is stopped in the case of the steering holding state. Therefore, it is possible to sufficiently suppress the uncomfortable feeling of steering given to the driver and efficiently correct the phase deviation.

In the example of FIG. 15, the steering speed dθh /
Although the second correction value S is set so as to be proportional to dt, in addition to this, the timing at which the steering angle θh passes the neutral position,
The second correction value S is set such that the second correction value S is set at the timing of the turning operation of the steering wheel 10 so that the first correction value Δθh decreases with the steering operation of the steering wheel 10.
If it is possible to set, there is no particular limitation.

In the fifth embodiment described above, the input angle sensor 21 is an absolute angle sensor, and the operating angle sensor 13
Although 1 is configured by a relative angle sensor, the input angle sensor 21 may be configured by a relative angle sensor and the operating angle sensor 131 may be configured by an absolute angle sensor. As an example of processing in this case,
In the flowchart of FIG. 4 described above, the first correction value Δ
The initial value of θh is (θphat−θp) / in S210.
In order to deal with G, the second correction value S may be set so that the first correction value Δθh decreases in accordance with the steering state, as in the processing illustrated in the flowchart of FIG.

[0099]

As described above, according to the vehicle steering control device of the first aspect, the control means for controlling the drive of the drive means transmits the detection result of the operating angle detecting means for detecting the absolute angle. Based on the transmission ratio set in the ratio variable mechanism, a configuration including an estimation means for estimating the absolute steering angle of the steering wheel is adopted. As a result, even when the relative angle sensor is used as the sensor for detecting the steering angle of the steering wheel, the control means can grasp the absolute steering angle of the steering wheel at the start of control.

According to the vehicle steering control device of the second aspect, the relationship between the angular pitch A of the lock position for prohibiting the variable operation of the transmission ratio and the angular pitch B for detecting the operating angle of the drive means is B <A. <2B. As a result, even when the position where the locking means is operated and the lock position where the transmission ratio variable mechanism is actually locked deviate by one angular pitch A,
This deviation can be reliably detected by the operating angle detection means.

According to the vehicle steering control device of the third aspect, the control means for controlling the drive of the drive means is arranged so that the angular deviation detected after the control is restarted decreases with the steering operation of the steering wheel. The configuration provided is adopted. As a result, when the angular deviation is detected, the angular deviation is allowed and steering control is performed, and it is possible to perform control so that the angular deviation gradually decreases with the steering operation of the steering wheel. It is possible to sufficiently suppress the uncomfortable steering feeling given to the driver during the correction control of.

According to the vehicle steering control device of the fourth aspect, when one of the steering angle detecting means and the operating angle detecting means is configured as the relative angle detecting means and the other is configured as the absolute angle detecting means, the steering angle is changed. A configuration is adopted that includes a determination unit that determines a failure of the relative angle detection unit based on the relationship among the angle, the operating angle, and the steering angle. As a result, it is possible to promptly determine that the relative angle detecting means has lost the detection memory, skips the reading of the detection target, etc., and deteriorates the reliability of the detection result.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a steering device.

FIG. 2 is a flowchart showing a control process according to the first embodiment, which is executed by a steering control device.

FIG. 3 is a map defining a relationship between a vehicle speed V and a transmission ratio G.

FIG. 4 is a flowchart showing a control process according to a second embodiment, which is executed by a steering control device.

FIG. 5 is a vertical cross-sectional view showing a transmission ratio variable mechanism according to a third embodiment.

6 is a cross-sectional view taken along the line AA in FIG.

7 is a sectional view taken along line BB in FIG.

FIG. 8 is a diagram showing a transition of each detection signal in three operating angle sensors.

FIG. 9 is a flowchart showing a control process according to a third embodiment, which is executed by a steering control device.

FIG. 10 is a flowchart showing a control process according to a fourth embodiment, which is executed by a steering control device.

FIG. 11 is an explanatory diagram showing a processing timing of failure determination processing.

12 is a flowchart showing the failure determination processing of FIG.

FIG. 13 is a flowchart showing a process according to a fifth embodiment, which is executed by the steering control device.

FIG. 14 is a flowchart showing a process of setting a second correction value S.

FIG. 15 is a map defining a relationship between a steering speed dθh / dt and a second correction value S.

[Explanation of symbols]

20 ... Input shaft, 21 ... Input angle sensor, 40 ... Output shaft, 4
DESCRIPTION OF SYMBOLS 1 ... Output angle sensor 61 ... Wheel speed sensor, 70 ... Steering control device, 100 ... Transmission ratio variable mechanism 110 ... Actuator, 131 ... Operating angle sensor

─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Shinri Nakatsu 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor Masahiko Shindo 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (56) References JP-A-8-26128 (JP, A) JP-A-7-2132 (JP, A) JP-A-3-292266 (JP, A) (58) Fields investigated (Int. Cl. ⁷⁾ , DB name) B62D 6/00 B62D 5/22

Claims (4)

(57) [Claims] 1. A vehicle steering control device including a transmission ratio variable mechanism for changing a transmission ratio between a steering angle of a steering wheel and a steering angle of steered wheels, wherein the steering angle of the steering wheel is set to a relative value. Steering angle detecting means for detecting the angle, drive means for rotationally driving the transmission ratio variable mechanism, operating angle detecting means for detecting the operating angle of the driving means by an absolute angle, and the operating angle detecting means set according to a traveling state. The control means performs drive control of the drive means based on the transmission ratio and the steering angle detected by the steering angle detection means, and the control means is the detection result of the operating angle detection means. A steering control device for a vehicle, comprising: an estimation unit that estimates an absolute steering angle of the steering wheel based on a transmission ratio set in the transmission ratio variable mechanism. 2. A steering control device for a vehicle, comprising a transmission ratio variable mechanism for changing a transmission ratio between a steering angle of a steering wheel and a steering angle of steered wheels, wherein the transmission ratio variable mechanism is rotationally driven. Driving means, an operating angle detecting means for detecting an operating angle of the driving means, and a lock position for prohibiting a variable operation of the transmission ratio in the transmission ratio varying mechanism are set for each angular pitch A (A> 0). The operating angle detecting means is a means for detecting the operating angle of the driving means in units of angular pitch B (B> 0), and the relationship between the angular pitches A and B is B < A vehicle steering control device characterized in that A <2B. 3. A vehicle steering control device comprising a transmission ratio variable mechanism for changing a transmission ratio between a steering angle of a steering wheel and a steering angle of steered wheels, the steering angle of a steering wheel being detected. Steering angle detection means, drive means for rotationally driving the variable transmission ratio mechanism, operating angle detection means for detecting an operating angle of the drive means, the transmission ratio set according to a traveling state, and the steering angle And a control unit that controls the drive of the drive unit based on the steering angle detected by the detection unit, and one of the steering angle detection unit and the operating angle detection unit detects a relative angle. Relative angle detection means, the other is configured as an absolute angle detection means for detecting an absolute angle, the control means, the absolute angle detected by the absolute angle detection means at the end of control, and the absolute angle detection means after the control is restarted. Raw between detected absolute angle A vehicle steering control device, characterized in that the drive control of the drive means is performed so that the twisted angle deviation decreases with the steering operation of the steering wheel. 4. A vehicle steering control device including a transmission ratio variable mechanism for changing a transmission ratio between a steering angle of a steering wheel and a steering angle of steered wheels, the steering angle of a steering wheel being detected. Steering angle detecting means, drive means for rotationally driving the variable transmission ratio mechanism, operating angle detecting means for detecting an operating angle of the driving means, and steering angle detecting means for detecting a steering angle of the steered wheels. The steering angle is set according to the traveling state and the steering angle detected by the steering angle detection means is included in the control means. Of the detection means and the operating angle detection means, one is configured as a relative angle detection means for detecting a relative angle, and the other is configured as an absolute angle detection means for detecting an absolute angle, and the control means is detected by the turning angle detection means. Steering angle detected by the steering angle detection means Was based on the operation angle detected by the steering angle and the operating angle detecting means, further comprising a steering control apparatus for a vehicle determination means for determining failure of said relative angle detecting means.