JP2004084810A - Range selector device for automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately learn a target angle of each range even if an angle detection value of a range selector shaft finely changes in a range selector device for driving the range selector shaft to turn with a motor. <P>SOLUTION: When an angle of the range selector shaft exists within a standard angle range to be set per each range, angular velocity of the range selector shaft is computed, and while low-pass filtering is performed to the angular velocity. The angle at two points wherein the angular velocity after the filtering crosses the predetermined value is obtained, and on the basis of a central value of the angle at the two points, a target angle of the range selector shaft in the corresponding range is learned. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a range switching device that switches a range of an automatic transmission by an actuator that is electrically driven and controlled, and more particularly, to a technique for learning a control target position of each range.
[0002]
[Prior art]
Conventionally, a predetermined play amount is provided in a power transmission path between an actuator that is electrically driven and controlled and a range switching shaft positioned at an angle corresponding to each range by a detent mechanism, and the range switching shaft has a predetermined play amount. 2. Description of the Related Art There is known a range switching device of an automatic transmission that can be switched to a plurality of ranges by rotation (see Japanese Patent Application Laid-Open No. 07-280083).
[0003]
Further, there is known a configuration in which a control target position of each range is learned in order to compensate for a shift in a detection position of a range switching valve (range switching shaft). In the device disclosed in Japanese Patent Application Laid-Open No. 07-08448, When the change in the position detection value becomes very small within the range recognized as the specific range position, the position detection value at that time is used as the learning value at the specific range position.
[0004]
[Problems to be solved by the invention]
However, as described above, the configuration in which a small change in the position detection value is determined has a problem that the target position of each range is likely to be erroneously learned due to the influence of noise and voltage fluctuation.
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a range of an automatic transmission that can learn a target position of each range without being greatly affected by noise superposition or voltage fluctuation. It is an object to provide a switching device.
[0005]
[Means for Solving the Problems]
Therefore, the invention according to claim 1 detects the angle of the range switching shaft, calculates the angular velocity of the range switching shaft based on the angle, and performs low-pass filter processing on the angular velocity.
When the angle of the range switching shaft is within a reference angle range preset for each range, the range switching shaft is set based on the median of the angles at two points where the low-pass filtered angular velocity crosses the determination value. Of learning the target angle in the range.
[0006]
According to the above configuration, the range switching shaft generates rotation fluctuation near the angle corresponding to each range even if the rotation of the actuator is constant due to the retraction action of the detent mechanism having play. It is perceived as a change in angular velocity.
Specifically, the position at which the angular velocity suddenly changes due to the pull-in action within the reference angle range, the angle at which the angular velocity subjected to the low-pass filter processing exceeds the determination value, and the increase / decrease direction are inverted, and the low-pass Is obtained as a median value with respect to the angle at the time when the angular velocity applied again crosses the determination value, and the target angle in the range is learned based on the central angular position.
[0007]
Therefore, the so-called valley position (position determined by the detent mechanism) of the detent mechanism can be accurately learned without being affected by a minute change in the detected angle value, and the angular velocity maintains the peak value for a certain period. However, it is possible to stably learn the valley position as the target angle.
In the invention according to claim 2, the angle of the range switching shaft is detected, the angular acceleration of the range switching shaft is calculated based on the angle, and the angular acceleration is subjected to a low-pass filter process,
When the angle of the range switching shaft is within a reference angle range preset for each range, the range switching is performed based on the median value of the angles at two points where the low-pass filtered angular acceleration crosses the determination value. The target angle of the shaft in the range is learned.
[0008]
The above configuration captures the retracting action of the detent mechanism as a change in angular acceleration, and determines the position at which the angular acceleration suddenly changes due to the retracting action within the reference angle range. The angle at the time of exceeding and the increasing / decreasing direction are reversed, and the angular acceleration subjected to the low-pass filter processing is obtained as a median of the angle at the time when the angular acceleration again crosses the determination value. Learn the target angle in the range.
[0009]
Therefore, the so-called valley position (position determined by the detent mechanism) of the detent mechanism can be accurately learned without being affected by the minute change of the detected angle value, and the angular acceleration maintains the peak value for a certain period. Even if there is, the valley position can be stably learned as the target angle.
According to the third aspect of the present invention, the angle of the range switching shaft is detected, the angular velocity and the angular acceleration of the range switching shaft are calculated based on the angle, and the angular velocity and the angular acceleration are each subjected to low-pass filtering.
When the angle of the range switching shaft is within a reference angle range set in advance for each range, the product of the angular velocity and the angular acceleration subjected to the low-pass filter processing is equal to the median of the angles at two points crossing the determination value. Based on this, the configuration is such that the target angle of the range switching shaft in the range is learned.
[0010]
In the above configuration, the retracting action of the detent mechanism is regarded as a change in the integrated value of the angular velocity and the angular acceleration, and the position at which the integrated value suddenly changes due to the retracting action within the reference angle range is subjected to low-pass filter processing. The angle at the time when the integrated value of the angular velocity and the angular acceleration exceeds the determination value, and the angle at which the increase / decrease direction is reversed and the integrated value crosses the determination value again are obtained as the median value of the angle. The target angle in the range is learned based on the angular position of.
[0011]
Therefore, the so-called valley position (position determined by the detent mechanism) of the detent mechanism can be accurately learned without being affected by a minute change in the detected angle value, and the integrated value of the angular velocity and the angular acceleration indicates the peak value. Even when the valley position is maintained for a certain period, the valley position can be stably learned as the target angle.
In the invention according to claims 1 to 3, even if the median value of the angles of the two points deviates from a so-called valley position (true target angle) of the detent mechanism, the amount of the deviation depends on the characteristics of the detent mechanism and the low-pass. Since the constant value is determined according to the filter processing, the target angle can be learned from the median value.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a system configuration diagram of a range switching device of an automatic transmission according to an embodiment.
In FIG. 1, a motor 2 (actuator) for driving a range switching valve 6 described later is attached to an automatic transmission 1 mounted on a vehicle.
[0013]
A reduction gear mechanism 3 is provided on the output shaft of the motor 2, and the range switching shaft 4 is driven to rotate via the reduction gear mechanism 3.
A predetermined play amount is provided in the rotational direction at the connection between the last stage of the reduction gear mechanism 3 and the range switching shaft 4.
A detent mechanism 5 for positioning the range switching shaft 4 at an angle corresponding to each of a plurality of ranges is attached to the range switching shaft 4.
[0014]
As shown in FIG. 2, the detent mechanism 5 includes a detent lever 5A that is fixed to the range switching shaft 4 and rotates integrally, and a roller that engages with a recess formed on the periphery of the detent lever 5A corresponding to each range. And a detent spring 5B that presses and biases the roller toward the recess.
The detent mechanism 5 moves the range switching shaft 4 by the above-described configuration to the P range (parking range), the R range (reverse range), the N range (neutral range), the D range (drive range), the 2 range, and the 1 range. Positioning at an angle corresponding to either of
[0015]
The rotational movement of the range switching shaft 4 is converted into the axial movement of the range switching valve 6 by the engagement between the detent lever 5A and the range switching valve 6, and the range switching valve 6 is displaced in the axial direction within the valve body 7. By doing so, the opening and closing of the hydraulic port is switched, and the line pressure is delivered according to each shift range.
A cam 9 is attached to the other end of the rod 8 having one end attached to the detent lever 5A, and a parking pole 10 that is swingably supported is swingably driven by sliding contact with the cam 9 to be in a P range position. In, the pawl 10a of the parking pole 10 meshes with the recess 11a of the parking gear 11, and the parking gear 11 is fixed.
[0016]
The range switching shaft 4 is provided with a potentiometer 21 for continuously detecting the angle of the range switching shaft 4, while an inhibitor switch 22 for detecting which of the ranges the automatic transmission 1 is switched to. Is provided.
Further, a range select switch 23 operated by the driver is provided.
[0017]
The signals from the potentiometer 21, the inhibitor switch 22, and the range select switch 23 are input to an A / T control unit (A / TC / U) 24.
The A / T control unit 24 sets a target angle of the range switching shaft 4 corresponding to the range select switch 23, and sets the target angle detected by the potentiometer 21 to the target angle. The drive signal of the motor 2 (duty drive signal for turning on / off the power supply at a high frequency) is feedback-controlled.
[0018]
The range switching shaft 4 is rotated by the electric drive control of the motor 2 by the A / T control unit 24, so that the range of the automatic transmission 1 is switched to the range required by the driver.
Further, the A / T control unit 24 has a function of learning a target angle for each of the ranges in order to compensate for a deviation of the detection angle by the potentiometer 21. FIG. This will be described according to the flowchart of FIG.
[0019]
In the flowchart of FIG. 3, in step S11, the angle of the range switching shaft 4 detected by the potentiometer 21 is read.
In step S12, it is determined whether the angle read in step S11 is included in any of the reference angle ranges (learning angle ranges) of the respective ranges including the reference target angle preset for each range (FIG. 6, 7).
[0020]
If it is within the reference angle range, the process proceeds to step S13, in which the angle of the range switching shaft 4 detected by the potentiometer 21 is differentiated to calculate the angular velocity.
In the next step S14, a digital low-pass filter process (LPF) is performed on the angular velocity calculated in step S13.
[0021]
In step S15, the angular velocity after the low-pass filter processing is compared with a rotation direction (range switching direction) of the range switching shaft 4 and a determination value preset according to the corresponding range at that time.
For example, as shown in FIG. 6A, assuming that the detection angle of the potentiometer 21 decreases and changes in the P → D switching direction, the angular velocity at this time becomes minus as shown in FIG. 6B. When the value is calculated as a value and the retracting operation of the detent mechanism 5 having play is started, the absolute value of the angular velocity sharply increases.
[0022]
Here, if a value at which a negative angular velocity crosses at the time of a sharp decrease in angle due to the retracting operation of the detent mechanism 5 is set as the determination value, the angular velocity is determined before and after the angular velocity shows a peak value by the retracting operation. Will cross the value.
As shown in FIGS. 6 and 7, the angular velocity is calculated as a plus or minus value depending on the rotation direction (range switching direction) of the range switching shaft 4, and the peak value of the angular velocity differs in the range. The value is different depending on the range switching direction and the range at that time.
[0023]
When the determination value is changed according to the range, it is not always necessary to set different determination values for all ranges. For example, when the peak value of the angular velocity is different between the P range and the other ranges. For example, a determination value for the P range and a determination value for other ranges may be set for each range switching direction.
From the result of the comparison between the angular velocity and the determination value in step S15, in step S16, the detection angles θa and θb of the potentiometer 21 at two points a and b where the angular velocity crosses the determination value before and after the peak value is obtained ( 6 and 7).
[0024]
In the next step S17, the median of the angles θa and θb of the two points a and b obtained in step S16 is calculated.
Median = (θa + θb) / 2
The median value roughly indicates an angle at which the angular velocity shows a peak value due to the pull-in operation of the detent mechanism 5, but is calculated as an angular position delayed from the actual peak position by performing a low-pass filter process on the angular velocity. In addition, there is a deviation between the angle at which the angular velocity shows the peak value and the valley position of the detent mechanism 5.
[0025]
However, since the deviation between the median and the valley position of the detent mechanism 5 is constant, the deviation angle is stored in advance, and in step S18, the angle obtained by correcting the median by the deviation angle is calculated. The target angle in the range is stored in the ROM (non-volatile memory) of the A / T control unit 24.
When performing range switching control, if the target angle corresponding to the target range has been learned, the A / T control unit 24 performs feedback control of the motor 2 based on the target angle obtained as a result of learning. For example, the motor 2 is feedback-controlled according to a reference target angle stored in advance.
[0026]
According to the above configuration, since the angular velocity is subjected to the low-pass filter processing and compared with the determination value, the two points a and b before and after the peak value of the angular velocity generated by the pull-in operation of the detent mechanism 5 are changed to a minute change of the detected angle value. Since the target angle can be obtained accurately without being affected, and the target angle is learned based on the median of the angles of the two points a and b corresponding to the peak occurrence time of the angular velocity. Even when continuing, the target angle of each range can be learned with high accuracy.
[0027]
The flowchart of FIG. 4 shows a second embodiment of the target angle learning control.
The second embodiment shown in the flowchart of FIG. 4 is different from the first embodiment shown in the flowchart of FIG. 3 in that the angular velocity is replaced with the angular acceleration.
In the flowchart of FIG. 4, the angle of the range switching shaft 4 is detected in step S21, and if it is determined in step S22 that the angle is within the reference angle range, the process proceeds to step S23.
[0028]
In step S23, the angle detected in step S21 is differentiated to calculate an angular velocity, and in the next step S24, the angular velocity is differentiated to calculate an angular acceleration.
In step S25, a digital low-pass filter process is performed on the angular acceleration calculated in step S24.
[0029]
In step S26, the angular acceleration after the low-pass filter processing is compared with a rotation direction (range switching direction) of the range switching shaft 4 and a determination value preset according to the corresponding range at that time.
In step S27, the detection angles θa and θb of the potentiometer 21 at two points a and b where the angular acceleration crosses the determination value before and after the peak value is obtained are obtained.
[0030]
In the next step S28, the median of the angles θa and θb of the two points a and b obtained in step S27 is calculated.
Median = (θa + θb) / 2
The median value roughly indicates an angle at which the angular acceleration shows a peak value due to the retraction operation of the detent mechanism 5, but is calculated as an angular position delayed from the actual peak position by performing low-pass filtering on the angular acceleration. In addition, there is a deviation between the angle at which the angular acceleration shows the peak value and the valley position of the detent mechanism 5.
[0031]
However, since the deviation between the median value and the valley position of the detent mechanism 5 is constant, the deviation angle is stored in advance, and in step S29, the angle obtained by correcting the median value with the deviation angle is calculated. The target angle in the range is stored in the ROM (non-volatile memory) of the A / T control unit 24.
According to the above configuration, since the angular acceleration is subjected to the low-pass filter processing and compared with the determination value, the two points a and b before and after the peak value of the angular acceleration generated by the retracting operation of the detent mechanism 5 are determined by the minute change of the angle detection value. And the target angle is learned with reference to the median of the angles θa and θb of the two points a and b corresponding to the peak occurrence time of the angular acceleration. Even when the state of maintaining the value continues, the target angle of each range can be learned with high accuracy.
[0032]
The flowchart of FIG. 5 shows a third embodiment of the learning control of the target angle.
The third embodiment shown in the flowchart of FIG. 5 differs from the first embodiment shown in the flowchart of FIG. 3 in that an integrated value of the angular velocity and the angular acceleration is used instead of the angular velocity.
In the flowchart of FIG. 5, the angle of the range switching shaft 4 is detected in step S31, and if it is determined in step S32 that the angle is within the reference angle range, the process proceeds to step S33.
[0033]
In step S33, the angular velocity is calculated by differentiating the angle detected in step S21.
The angular velocity calculated in step S33 is subjected to digital low-pass filtering in step S34, and is used for calculating angular acceleration in step S35.
[0034]
Then, the digital low-pass filter processing is performed in step S36 on the angular acceleration calculated based on the angular velocity before the digital low-pass filter processing is performed.
Then, the angular velocity subjected to the digital low-pass filter processing (LPF) and the angular acceleration similarly subjected to the digital low-pass filter processing are integrated in step S37.
[0035]
In step S38, the integrated value (= post-LPF angular velocity × LPF rear angular acceleration) and a determination value preset according to the rotation direction of the range switching shaft 4 (range switching direction) and the corresponding range at that time are obtained. Compare.
Note that the integrated value has no sign inversion in the range switching direction and the difference in peak level between the ranges is small, so that the determination value is set in accordance with the range switching direction and / or the determination value is determined in accordance with the corresponding range. The setting may be omitted.
[0036]
In step S39, the detection angles θa and θb of the potentiometer 21 at two points a and b crossing the determination value before and after the integrated value indicates the peak value are obtained (see FIG. 7).
In the next step S40, the median of the angles θa and θb of the two points a and b obtained in step S39 is calculated.
[0037]
Median = (θa + θb) / 2
The median value roughly indicates an angle at which the integrated value (LPF rear angular velocity × LPF rear angular acceleration) shows a peak value due to the retracting operation of the detent mechanism 5, and the angular velocity and the angular acceleration respectively subjected to the low-pass filter processing. Is used, the angle position is calculated as an angle position delayed from the actual peak position, and there is a deviation between the angle at which the integrated value indicates the peak value and the valley position of the detent mechanism 5.
[0038]
However, since the deviation between the median value and the valley position of the detent mechanism 5 is constant, the deviation angle is stored in advance, and in step S41, the angle obtained by correcting the median value with the deviation angle is calculated. The target angle in the range is stored in the ROM (non-volatile memory) of the A / T control unit 24.
According to the above configuration, since the integrated value of the angular velocity and the angular acceleration subjected to the low-pass filter processing are compared with the determination value, two points before and after the peak value of the integrated value generated by the retracting operation of the detent mechanism 5 are determined. Since the target angle can be obtained accurately without being affected by a minute change in the detected angle value, and the target angle is learned based on the median value of the angles of the two points corresponding to the peak occurrence time of the integrated value. Even if the state where the peak value is maintained continues, the target angle of each range can be learned with high accuracy.
[0039]
In the first to third embodiments, the target angle is individually learned for each range switching direction, the target angle is set based on the range switching direction and the target range, and the feedback control of the motor 2 is performed. You may do it.
Further, technical ideas other than the claims that can be grasped from the above embodiment will be described below together with their effects.
(A) The range switching device for an automatic transmission according to any one of claims 1 to 3, wherein the determination value is set to a different value according to the range. Switching device.
[0040]
According to the above configuration, the judgment value is switched in response to the difference in the peak level of the angular velocity, the angular acceleration, and the integrated value of the angular velocity and the angular acceleration in each range due to a difference in the shape of the detent mechanism corresponding to each range. .
Therefore, even if the peak levels such as the angular velocities are different in each range, the optimum judgment value for the judgment of the peak occurrence angle can be set, and the target angle can be learned with high accuracy.
(B) In the range switching device for an automatic transmission according to any one of claims 1 to 3, the determination value is set to a different value in accordance with a range switching direction. Range switching device.
[0041]
According to the above configuration, when the peak levels such as the angular velocities generated in the same range are different depending on the switching direction of the range, the determination value is set corresponding to the difference in the peak level.
Therefore, even if the peak level differs depending on the range switching direction, it is possible to set the optimum determination value for determining the peak occurrence angle, and to learn the target angle with high accuracy.
(C) A range switching device for an automatic transmission according to any one of claims 1 to 3,
A range switching device for an automatic transmission, wherein the target angle is individually learned for each range switching direction.
[0042]
According to the above configuration, for example, as the target angle of the neutral range N, the target range when switching from the parking range P or the reverse range R to the neutral range N and the target range when switching from the drive range D to the neutral range N are individually set. Even if the target range after switching is the same neutral range N, the target angle is set depending on which range to switch from.
[0043]
Therefore, it is possible to learn a target angle that is different depending on the range switching direction and is optimal for convergence to the valley position of the detent mechanism, and high convergence stability can be obtained.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram showing a range switching device of an automatic transmission.
FIG. 2 is a perspective view showing a drive mechanism of a range switching shaft.
FIG. 3 is a flowchart showing a first embodiment of learning control of a target angle.
FIG. 4 is a flowchart showing a second embodiment of target angle learning control;
FIG. 5 is a flowchart showing a third embodiment of learning control of a target angle.
FIG. 6 is a timing chart showing changes in angle, angular velocity, and angular velocity × angular acceleration when switching from P to D range.
FIG. 7 is a timing chart showing changes in angle, angular velocity, and angular velocity × angular acceleration when switching from D to P range.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Automatic transmission, 2 ... Motor (actuator), 3 ... Reduction mechanism, 4 ... Range switching shaft, 5 ... Detent mechanism, 6 ... Range switching valve, 21 ... Potentiometer, 22 ... Inhibitor switch, 23 ... Range select switch, 24 A / T control unit

Claims (3)

A predetermined amount of play is provided in a power transmission path between an actuator that is electrically driven and controlled and a range switching shaft that is positioned at an angle corresponding to each range by a detent mechanism, and a plurality of play amounts are provided by rotation of the range switching shaft. In a range switching device of an automatic transmission that can be switched to a range of
Detecting the angle of the range switching shaft, calculating the angular velocity of the range switching shaft based on the angle, performing low-pass filter processing on the angular velocity,
When the angle of the range switching shaft is within a reference angle range preset for each range, the range based on the median of the angles at two points where the angular velocity subjected to the low-pass filter processing crosses the determination value. A range switching device for an automatic transmission, wherein a target angle of the switching shaft in the range is learned. A predetermined amount of play is provided in a power transmission path between an actuator that is electrically driven and controlled and a range switching shaft that is positioned at an angle corresponding to each range by a detent mechanism, and a plurality of play amounts are provided by rotation of the range switching shaft. In a range switching device of an automatic transmission that can be switched to a range of
Detecting the angle of the range switching shaft, calculating the angular acceleration of the range switching shaft based on the angle, performing low-pass filtering on the angular acceleration,
When the angle of the range switching shaft is within a reference angle range preset for each range, the low-pass filtered angular acceleration is based on a median value of angles at two points crossing a determination value. A range switching device for an automatic transmission, which learns a target angle of a range switching shaft in the range. A predetermined amount of play is provided in a power transmission path between an actuator that is electrically driven and controlled and a range switching shaft that is positioned at an angle corresponding to each range by a detent mechanism, and a plurality of play amounts are provided by rotation of the range switching shaft. In a range switching device of an automatic transmission that can be switched to a range of
Detecting the angle of the range switching shaft, calculating the angular velocity and angular acceleration of the range switching shaft based on the angle, performing low-pass filter processing on the angular velocity and angular acceleration, respectively.
When the angle of the range switching shaft is within a reference angle range preset for each range, the median value of the angles at two points at which the product of the angular velocity and the angular acceleration subjected to the low-pass filter processing crosses the determination value. A range switching device for an automatic transmission, wherein a target angle of the range switching shaft in the range is learned based on the target angle.

Images