JP4089096B2 - Vehicle steering control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle steering control device including a transmission ratio variable mechanism.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a steering control device equipped with a transmission ratio variable mechanism that changes a transmission ratio between a steering angle of a steering wheel and a turning angle of a steered wheel is known. For example, Japanese Patent Laid-Open No. 11-34894 discloses a steering control device including a lock mechanism that locks a differential mechanism in such a transmission ratio variable mechanism. This lock mechanism is a mechanism for engaging the convex portion of the lock arm fixed to the motor housing side with the concave portion of the rotating body fixed to the motor rotation shaft of the transmission ratio variable mechanism.
[0003]
[Problems to be solved by the invention]
Since the lock mechanism is a mechanism that engages the concave portion and the convex portion as described above, the positional relationship between the concave portion of the rotating body and the convex portion of the lock arm does not match at the time of locking, and the lock may not be applied well. In addition, when the lock is released, the lock may not be released successfully due to the biting between the lock arm and the rotating body.
[0004]
The present invention has been made to solve such problems, and an object of the present invention is to provide a vehicle steering control device that can reliably operate a lock mechanism of a transmission ratio variable mechanism.
[0005]
[Means for Solving the Problems]
Therefore, a vehicle steering control device according to claim 1 is a vehicle steering control device that performs steering control of a vehicle, and includes an input shaft connected to a steering wheel side and an output shaft connected to a steered wheel side. The transmission ratio variable means for changing the transmission ratio between the input shaft and the output shaft by the rotational drive of the motor, the rotational position detection means for detecting the rotational position of the motor, and the tilting with respect to the stator side constituting the motor A tilting member supported by the tilting member, a driving unit for tilting the tilting member, a rotating member fixed to a rotor constituting the motor and having lockable portions that can be locked with the tilting member, and a driving unit. And a lock control means for controlling the unlocking of the tilting member and the rotating member, and the lock control means includes a driving means for separating the tilting member from the rotating member. Drive A tilt control means for, constituting a motor control means for reciprocating the motor at a predetermined range.
[0006]
The differential mechanism in the transmission ratio variable means is locked and unlocked by the locking and unlocking of the tilting member and the rotating member. When the locking is released , the lock control means controls the operation of the driving means. In addition, the motor operation is controlled. As a result , even when a biting occurs between the tilting member and the rotating member at the time of unlocking, it is possible to perform control to release this biting by operating the motor.
Further, when the lock is released, the tilting member is tilted by the tilting control means so as to be separated from the rotating member. During this control process, the motor is reciprocated within a predetermined range by the motor control means. As a result, the locking member of the rotating member is oscillatingly displaced with respect to the tilting member, and this movement acts so that the biting between the tilting member and the rotating member is released.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[0016]
FIG. 1 shows a configuration of a steering control device including a transmission ratio variable mechanism according to the first embodiment.
[0017]
The transmission ratio variable mechanism 100 has an input shaft 20 connected to the steering handle 10 side and an output shaft 40 connected to the wheel FW side, and the steering angle θh of the steering handle 10 with respect to the input shaft 20. A steering angle sensor 60 is provided for detecting the above. The output shaft 40 is connected to a rack shaft 51 via a rack and pinion gear device 50, and wheels FW are connected to both sides of the rack shaft 51.
[0018]
FIG. 2 schematically shows the transmission ratio variable mechanism 100 in an enlarged manner. The transmission ratio variable mechanism 100 includes a motor 110, a speed reducer 120, and a lock mechanism 130, and has a function of changing the transmission ratio of the rotation amount between the input shaft 20 and the output shaft 40.
[0019]
The motor 110 includes a stator 111 fixed in the motor housing 101 and a rotor 112 rotatably supported in the motor housing 101, and a rotation angle sensor 102 that detects a rotation angle θm of the motor (see FIG. 1). The servomotor which can control a rotation position is comprised.
[0020]
The reduction gear 120 constitutes a planetary gear mechanism, and a sun gear 121 located at the center is fixed to a rotating shaft 113 that rotates integrally with the rotor 112. In addition, planetary gears 122 that revolve around the sun gear 121 while rotating are arranged at equal intervals around the sun gear 121, and each planetary gear 122 is rotatably supported by a carrier 123 connected to the input shaft 20. . Further, a ring gear 124 formed on the inner peripheral surface of the motor housing 101 is arranged so as to surround each planetary gear 122, and the motor housing 101 is connected to the output shaft 40.
[0021]
In addition, a lock mechanism 130 that locks the differential mechanism of the variable transmission ratio mechanism is provided at a portion indicated by line AA between the motor 110 and the speed reducer 120. As shown in FIG. 3, the lock mechanism 130 includes a disk-shaped lock holder 140 and a lock arm 150 curved in an arc shape.
[0022]
The lock holder 140 is fixed to a rotary shaft 113 that penetrates the center portion, and the lock holder 140, the rotary shaft 113, and the rotor 112 rotate integrally. Engagement recesses 141 are formed at predetermined intervals on the peripheral edge of the lock holder 140.
[0023]
On the other hand, the lock arm 150 has an engagement projection 151 that engages in the engagement recess 141 of the lock holder 140 and protrudes toward the lock holder 140. The base end portion of the lock arm 150 is supported by a support pin 152 fixed to the motor housing 101 so as to be tiltable about the support pin 152, and an electromagnetic coil 154 is provided at the distal end portion of the lock arm 150. A metal plate (magnet plate) 155 fixed on the motor housing 101 side is disposed at a position facing the electromagnetic coil 154. Further, the other end of a spring 153 having one end fixed to the motor housing 101 is fixed to the tip of the lock arm 150.
[0024]
In this way, the lock arm 150 is always urged to tilt toward the lock holder 140 around the support pin 152 by the action of the spring 153, and as shown in FIG. The engagement protrusion 151 of the lock arm 150 enters the state 141, and the lock holder 140 and the lock arm 150 are locked to each other, thereby preventing relative rotation between the motor housing 101 and the rotor 112. For this reason, the transmission ratio variable mechanism becomes inoperable, and the transmission ratio variable mechanism 100 is locked.
[0025]
On the other hand, when the electromagnetic coil 154 is energized, an electromagnetic repulsive force is generated between the electromagnetic coil 154 and the action causes the lock arm 150 to be separated from the lock holder 140 as shown in FIG. As a result, the engaging projection 151 of the lock arm 150 moves out of the engaging recess 141 of the lock holder 140, and the lock holder 140 and the lock arm 150 are unlocked. Thus, the motor housing 101 and the rotor 112 are in a state in which relative rotation is possible, and the transmission ratio variable mechanism 100 is a mechanism that is released from the locked state.
[0026]
Here, if the rotation angle of the output shaft 40 is the output angle θp, the relationship between the steering angle θh, the rotation angle θm of the motor 110, and the output angle θp is expressed by the equation (1), and the steering angle θh, output angle θp, transmission Since the relationship of the ratio G is defined by equation (2), the rotation angle θm of the motor 110 can be expressed by equation (3) from equations (1) and (2). Note that “K” in the equation is a reduction ratio of the reduction gear 120.
[0027]
θp = θh + K · θm (1)
θp = G · θh (2)
θm = (G−1) · θh / K (3)
Therefore, the transmission ratio control between the input shaft 20 and the output shaft 40 is controlled by controlling the rotation angle θm of the motor 110 according to the steering angle θh based on the set transmission ratio G based on the equation (3). It can be carried out. Since the output angle θp corresponds to the stroke position of the rack shaft 51 and the stroke position of the rack shaft 51 corresponds to the turning angle of the wheel FW, the steering angle θh and the rotation angle θm are detected (1 ), The output angle θp can be detected, and the turning angle of the wheel FW can be detected based on the detected output angle θp.
[0028]
Operation control of the transmission ratio variable mechanism 100 and the lock mechanism 130 configured as described above is performed by the steering control device 70, and the steering control device 70 detects the detection results of the steering angle sensor 60, the rotation angle sensor 102, and the vehicle speed sensor 71. Then, the control signal Is is output to the motor 110 to drive the transmission ratio variable mechanism 30. Further, at the time of locking and unlocking, predetermined control such as energization control for the electromagnetic coil 154 is performed.
[0029]
Here, the process implemented by the steering control apparatus 70 is demonstrated along the flowchart of FIG.
[0030]
This flowchart is activated by turning on the ignition switch. While the ignition switch is in the OFF state, the lock mechanism 130 of the transmission ratio variable mechanism 100 is operated and is in the locked state. Therefore, the process proceeds to step 200 (hereinafter, step is referred to as “S”), and the transmission ratio is variable. The lock release control for releasing the lock state of the mechanism 100 is executed.
[0031]
This unlock control is shown in the flowchart of FIG.
[0032]
First, in S <b> 202, energization of the electromagnetic coil 154 is started, and a driving force is applied to the lock arm 150 in a direction away from the lock holder 140.
[0033]
In subsequent S204, a predetermined control signal Istart1 defined in advance is output to the motor 110. This control signal Istart1 is a control signal set in advance to reciprocate the motor 110 in a predetermined range in a vibrating manner. The reciprocating range includes the engagement convex portion 151 of the lock arm 150 and the lock holder 140. A range sufficient to release the engagement with the engaging recess 141 is set. In the subsequent S206, the rotation angle θm1 of the motor 110 at the time when the processing of S204 is completed is read.
[0034]
In subsequent S208, a predetermined control signal Istart2 defined in advance is output to the motor 110. The control signal Istart2 is a control signal set in advance so that the lock holder 140 rotates at a rotation angle that is larger than the formation width of the engagement recess 141, for example. In the subsequent S210, the rotation angle θm2 of the motor 110 at the time when the processing of S208 is completed is read.
[0035]
In the subsequent S212, the deviation Δ between the rotation angle θm2 and the rotation angle θm1 is set as Δ = θm2−θm1, and in the subsequent S214, it is determined whether the deviation Δ is equal to or greater than the threshold value Δth. This threshold value Δth is, for example, the rotation angle of the motor 110 corresponding to the formation width of the engagement recess 141 in the lock holder 140.
[0036]
As a result, if “Yes” is determined in S214, the lock holder 140 has been rotated more than the formation width of the engagement recess 141, and thus the engagement with the lock arm 150 has been released. This routine can be finished as it is. On the other hand, if “No” is determined in S214, the lock holder 140 and the lock arm 150 have not been released for some reason such as biting or malfunction of the lock arm 150. In this case, the process proceeds to S216, the failure display lamp indicating the failure of the lock mechanism 130 is turned on, the driver is notified of the occurrence of the failure, and this routine is terminated.
[0037]
Thus, immediately after the ignition switch is turned on, the lock release control shown in S202 to S216 is executed. Note that the processing order of S202 and S204 is not particularly limited, and may be executed simultaneously.
[0038]
Returning to FIG. 5 again, after performing the lock release control (S200), the process proceeds to S102. In S102, the steering angle θh detected by the steering angle sensor 60, the rotation angle θm of the motor 110 detected by the rotation angle sensor 102, and the vehicle speed V detected by the vehicle speed sensor 71 are read.
[0039]
In the subsequent S104, a map search is performed based on the vehicle speed V read in S102 from the map showing the relationship between the vehicle speed V and the transmission ratio G shown in FIG. 7, and the transmission ratio G corresponding to the vehicle speed V is set. Then, using the above equation (3), the target rotation angle θmm of the motor 110 is set based on the steering angle θh read in S102 and the transmission ratio G set in S104.
[0040]
In subsequent S108, an angular deviation e between the target rotation angle θmm set in S106 and the rotation angle θm read in S102 is set as e = θmm−θm.
[0041]
In subsequent S110, the control signal Is for controlling the motor 110 is determined so that the deviation e is set to 0 without overshooting. As an example of this process, the control signal Is can be determined by appropriately setting a parameter for PID control based on an arithmetic expression of Is = C (s) · e. Note that (s) in the formula is a Laplace operator.
[0042]
In subsequent S112, the control signal Is determined in S110 is output to the motor 110, the motor 110 is driven in accordance with the control signal Is, and then the process proceeds to S114 to determine whether the ignition switch (IG) is turned off. In the case of “No”, the process returns to S102, and the processes after S102 are repeatedly executed until “Yes” is determined in S114.
[0043]
When the ignition switch is turned off (“Yes” in S114), the process proceeds to S300, and lock control for locking the transmission ratio variable mechanism 100 is executed.
[0044]
This lock control is shown in the flowchart of FIG.
[0045]
In S310, first, energization of the electromagnetic coil 154 is stopped. As a result, the lock arm 150 tilts toward the lock holder 140 around the support pin 152 by the restoring force of the spring 153.
[0046]
In subsequent S312, the rotation angle θm of the motor 110 indicating the rotation position of the lock holder 140 at this time is read.
[0047]
In the steering control device 70, the rotation position where the lock holder 140 can be locked with the lock arm 150 is stored in advance, and in the subsequent S314, the nearest lockable position θmr is selected with respect to the rotation angle θm read in S312. .
[0048]
In subsequent steps S316 to S320, the lockable position θmr selected in step S314 is treated as the target rotation angle, and the same processing as in steps S108 to S112 is performed.
[0049]
By performing such a lock control process, the lock holder 140 is rotationally driven to the lockable position, so that the engagement convex portion 151 of the lock arm 150 is securely inserted into the engagement concave portion 141 of the lock holder 140. The locking operation is surely performed.
[0050]
Also, the lock control in S300 can be performed as shown in FIG.
[0051]
First, after stopping energization of 154 to the electromagnetic coil in S330, the control signal Is is set as Is = C (s) · Econst using a predetermined deviation Econst in S332, and the control signal set in S332 in S334. The motor 110 is driven according to Is.
[0052]
The deviation Econst is a value defined as an angle deviation corresponding to the formation pitch of the engagement recesses 141 formed in the lock holder 140. While the lock holder 140 rotates by the formation pitch of the engagement recesses 141, the lock Econst Since the engagement concave portion 141 of the holder 140 always passes through the position facing the engagement convex portion 151 of the lock arm 150, the locking operation is surely performed.
[0053]
Then, after a predetermined time has passed, the process proceeds to S336, where the rotation angle θm of the motor 110 indicating the rotation position of the lock holder 140 at this time is read. In the subsequent S338, is the rotation angle θm read in S336 a pre-stored lockable position? Judging. If the determination is “Yes”, it can be confirmed that the locking operation between the lock holder 140 and the lock arm 150 has been performed reliably, and thus this routine is terminated. If “No” is determined in S338, the lock holder 140 and the lock arm 150 are not engaged with each other for some reason, and the lock holder 140 has rotated past the lockable position or stopped before the lockable position. It will be done. In such a case, the process proceeds to S340, the failure display lamp indicating the failure of the lock mechanism 130 is turned on, the driver is notified of the occurrence of the failure, and this routine is terminated.
[0054]
If “No” is determined in S338, the process from S330 onward can be repeated a predetermined number of times, and then the process can proceed to S340.
[0055]
In the embodiment described above, the lock holder 140 and the lock arm 150 are exemplified as the lock mechanism 130, but the present invention is not limited to this shape and arrangement state, and the lock mechanism 130 is formed with a concave portion on one side and a convex portion on the other side. If it is, it will not specifically limit.
[0056]
In addition, the locking operation and the unlocking operation described in the embodiment are not limited to the example described, and for example, the locking operation and the unlocking operation that are performed when the rack stroke ends or when the system fails are applied. be able to.
[0057]
【The invention's effect】
As described above, according to the vehicle steering control device according to each claim, by the lock control means, in addition to the operation control of the drive unit, since the operation control of the motor, during unlocking, the tilting member and the rotating member Even when there is a bite between the two, it is possible to perform control to release this bite by operating the motor. Thus, the lock mechanism 130 of the transmission ratio variable mechanism can be reliably operated.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of a steering control device according to an embodiment.
FIG. 2 is a cross-sectional view showing a transmission ratio variable mechanism.
3 is a plan view of a lock mechanism showing a locked state in a cross section taken along line AA in FIG. 2; FIG.
4 is a plan view of the lock mechanism showing the unlocked state in a cross section taken along line AA in FIG. 2; FIG.
FIG. 5 is a flowchart showing variable control of a transmission ratio.
FIG. 6 is a flowchart showing lock release control.
FIG. 7 is a map that defines the relationship between the vehicle speed V and the transmission ratio G;
FIG. 8 is a flowchart showing lock control.
FIG. 9 is a flowchart showing lock control.
[Explanation of symbols]
FW ... wheels (steered wheels), 10 ... steering handle, 100 ... transmission ratio variable mechanism 102 ... rotation angle sensor, 110 ... motor, 111 ... stator 112 ... rotor, 120 ... speed reducer, 130 ... lock mechanism,
140: Lock holder (rotating member), 141: Engaging recess (lockable portion)
150 ... Lock arm (tilting member)

Claims (1)

A vehicle steering control device that performs steering control of a vehicle,
A transmission ratio variable means having an input shaft connected to the steering wheel side and an output shaft connected to the steered wheel side, and changing a transmission ratio between the input shaft and the output shaft by rotational driving of the motor;
Rotational position detecting means for detecting the rotational position of the motor;
A tilting member supported to be tiltable with respect to the stator side constituting the motor;
Drive means for tilting the tilting member;
A rotating member fixed to a rotor constituting the motor, and having a locking portion that can be locked with the tilting member at a predetermined interval;
A lock control means for controlling the operation of the motor together with the operation control of the drive means, and controlling the unlocking of the tilting member and the rotation member ;
The lock control means includes
Tilt control means for driving the drive means so that the tilt member is separated from the rotating member;
Motor control means and the vehicle steering control apparatus Ru comprising a reciprocating said motor in a predetermined range.

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