JP3470402B2 - Vehicle turning angle detection 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 angle detection device, and more particularly to a vehicle steering angle detection device in which a potentiometer type analog steering angle sensor is attached to a steering wheel.

[0002]

2. Description of the Related Art A steering angle sensor used in this type of steering angle detecting device is a potentiometer type analog steering angle sensor.
It is roughly classified into a rotary encoder type digital steering angle sensor. The former analog type steering angle sensor fixes the main body of the potentiometer on the vehicle body side, and changes the output voltage due to the relative rotation of the slider fixed to the steering shaft and the main body, for example. Corners) are detected.

On the other hand, the latter digital steering angle sensor is
For example, a rotary encoder is attached to the steering shaft, and the absolute value of the steering angle of the steering wheel is detected by sampling a two-phase pulse signal output with the rotation of the steering wheel.

By the way, if the analog steering angle sensor is directly attached to the steering handle as described above, the steering handle or the steering shaft rotates about three times, so that the neutral position of the steering angle cannot be uniquely determined. It will be.

On the other hand, also in the digital steering angle sensor, in order to determine the relative value of the steering angle, it is necessary to determine the neutral position of the steering wheel with respect to the steering angle. In this case, it is conceivable to attach a sensor that generates a single-shot pulse signal corresponding to the neutral position of the steering wheel.
Since it rotates, the neutral position of the steering angle cannot be uniquely determined.

Furthermore, in both analog type and digital type steering angle sensors, the ignition switch O
If the steering wheel is turned after FF, the neutral position of the steering angle indicated by the output of the steering angle sensor may deviate from the neutral position of the steering wheel. Therefore, after the ignition switch is turned on, the output of the steering angle sensor is The neutral position of the steering wheel steering angle shown must correspond to the neutral position of the steering wheel or the steering angle.

To solve such a problem, for example, in Japanese Patent Laid-Open No. 4-38419, a steering angle is estimated from the wheel speeds of the left and right wheels in a rotary encoder type digital steering angle sensor. At the same time, the technical idea of determining the neutral position of the steering angle (steering handle) from the estimated steering angle is disclosed. In addition, JP-A-4-31
In Japanese Patent No. 8414, a potentio-type analog steering angle sensor and a rotary encoder-type digital steering angle sensor are provided, and steering is performed based on the output of the analog steering angle sensor until the neutral position is determined. A configuration for calculating the corner is shown.

According to the former, since the neutral position of the turning angle can be obtained even in the turning state of the vehicle, the turning angle can be detected early by using the rudder angle sensor.
Further, according to the latter, since the steering angle is calculated based on the output of the analog steering angle sensor until the neutral position is determined after the ignition switch is turned on, erroneous detection of the steering angle is prevented. Become.

[0009]

However, even in the conventional techniques described in the above publications, the following problems to be solved remain.

First, according to the former, since the steering angle is estimated based on the difference between the wheel speeds of the left and right wheels, there is a problem in that the steering angle cannot be obtained accurately.

Next, according to the latter, a linear sliding type potentiometer is adopted as an analog steering angle sensor to detect the stroke amount of the tie rod transmitted by decelerating the operation of the steering wheel. Therefore, even in this case, the steering angle cannot be obtained accurately.

When the analog steering angle sensor is attached to the steering wheel, a reduction gear is provided between the steering shaft and the rotating shaft of the steering angle sensor,
If the rotation of the steering wheel or steering shaft is decelerated at a ratio of, for example, 1/3 or less and transmitted to the steering angle sensor, the output value of the steering angle sensor can be uniquely associated with the steering wheel angle. However, there is a drawback that the manufacturing cost becomes high.

The present invention addresses the above problem in the case where an analog steering angle sensor is attached to a steering wheel, and the steering angle can be quickly changed even after the ignition switch is turned on without increasing the manufacturing cost. In addition, the main purpose is to enable accurate detection.

[0014]

That is, the invention of claim 1 of the present application (hereinafter referred to as the first invention) is a steering angle detecting device for a vehicle in which a potentiometer type analog steering angle sensor is attached to a steering handle. In the above, the steering angle sensor and the steering wheel are interlocked and coupled at a rotation ratio of 1: 1, yaw rate detecting means for detecting a yaw rate of the vehicle, vehicle speed detecting means for detecting a vehicle speed of the vehicle, and the steering angle. The steering angle range covered by the output signal of the sensor is a neutral zone within a predetermined range including at least the neutral position, the output signals of the steering angle sensors in the right zone and the left zone respectively adjacent to the neutral zone have the same value. It is divided into the three zones shown, and which of these zones the current steering angle is located in is detected by each of the above detection means. Characterized by providing a determining zone determination means based on the rate and vehicle speed.

The invention of claim 2 of the present application (hereinafter referred to as the second
(Invention), the zone determination means in the first invention is configured to perform zone determination by comparing the actual yaw rate indicated by the signal from the yaw rate detection means with a reference yaw rate preset according to the vehicle speed. It is characterized by having done.

The invention of claim 3 of the present application (hereinafter referred to as the third invention) is provided with a wheel speed detecting means for detecting a wheel speed in addition to the configuration of the first and second inventions.
The zone determination means is configured to perform zone determination based on the wheel speed difference between the left and right wheels detected by the wheel speed detection means, the yaw rate, and the vehicle speed.

The invention of claim 4 of the present application (hereinafter, referred to as the fourth
(Invention), in the configuration of the first to third invention,
The yaw rate or the wheel speed difference is set so that the zone determination is performed at the boundary between the neutral zone and the right zone or the left zone.

Further, according to the invention of claim 5 of the present application (hereinafter referred to as the fifth invention), in addition to the configuration of the first to fourth inventions, the output signal from the steering angle sensor is based on a preset reference value. Is provided with zone shift judging means for judging shift between adjacent zones when a large change is shown.

The invention of claim 6 of the present application (hereinafter, referred to as the sixth
(Invention) is a potentiometer type analog rudder angle sensor.
Steering angle detection of the vehicle attached to the steering wheel
In the device, the steering angle sensor and steering handle
And the vehicle are linked together at a rotation ratio of 1: 1 and
Wheel speed detecting means for detecting the wheel speed of the vehicle and the vehicle speed of the vehicle.
And vehicle speed detection means for detecting
The steering angle range covered by at least the neutral position
Neutral zone within a specified range, adjacent to each neutral zone
The output signals of the steering angle sensor in the right and left zones
The current rudder is divided into three zones that show the same value.
The corner is located in any of these zones
Is the wheel speed difference between the left and right wheels detected by the above detection means
And zone determination means for determining based on the vehicle speed
It is characterized by

The invention according to claim 7 of the present application (hereinafter referred to as the seventh invention) is, in the configuration of the sixth invention, a wheel so that zone determination is performed at the boundary between the neutral zone and the right zone or the left zone. The feature is that the speed difference is set.

The invention of claim 8 of the present application (hereinafter,
In addition to the configurations of the sixth and seventh inventions,
It is characterized in that a zone shift judging means for judging the shift between the adjacent zones when the output signal from the steering angle sensor shows a change larger than a preset reference value is provided.

[0022]

[0023]

[0024]

[0025]

According to the above construction, the following operation can be obtained.

That is, in any of the first to fifth inventions, a potentiometer type analog rudder angle sensor is attached, and the rudder angle sensor and the steering wheel are interlocked at a rotation ratio of 1: 1. Therefore, the turning angle can be accurately detected.

In that case, the output signal of the steering angle sensor shows the same value at different rotational positions of the steering wheel, but the range of the steering angle covered by the output signal of the steering angle sensor is at least at the neutral position. The present steering angle is divided into three zones in which the output signals of the steering angle sensors of the neutral zone within a predetermined range including the right zone and the left zone respectively adjacent to the neutral zone show the same value, and the current steering angle is within these zones. Which zone among them is located is determined based on at least the yaw rate and the vehicle speed, so that the output signal of the steering angle sensor can be uniquely associated with the steering angle. I of ignition switch
Even after N, the steering angle can be detected as soon as possible. Moreover, since the range in which the steering angle is located is determined based on the yaw rate and the vehicle speed,
There is an advantage that the error is reduced as compared with the case where the steering angle or the neutral position is directly calculated based on these measured values. Further, since the sensor for determining the neutral position and the reduction gear are not required, the cost can be reduced.

Further, according to the second aspect of the invention, for example, the zone determination is made by comparing the actual yaw rate indicated by the output from the yaw rate sensor with the reference yaw rate preset according to the vehicle speed. The zone determination will be performed accurately.

Further, according to the third aspect of the invention, the zone determination is performed based on the wheel speed difference between the left and right wheels of the vehicle, the yaw rate, and the vehicle speed, so that the zone determination can be performed more accurately.

According to the fourth aspect of the invention, the yaw rate or the wheel speed difference is set so that the zone determination is made at the boundary between the neutral zone and the right zone or the left zone. Therefore, for example, the actual yaw rate is the reference yaw rate. When it is larger than the above, the right zone is judged, and when the actual yaw rate is smaller than the reference yaw rate, it is judged as the neutral zone, so that the zone judgment is surely made.

Further, according to the fifth aspect of the invention, when the output signal from the steering angle sensor shows a change larger than a preset reference value, the transition between adjacent zones is judged. It is possible to easily determine the transition between zones and prevent the erroneous determination by setting the reference value so that the output change is faster than the steering speed of a person.

In any of the sixth to eighth inventions, a potentiometer type analog rudder angle sensor is attached, and the rudder angle sensor and the steering wheel are interlocked at a rotation ratio of 1: 1. Therefore, the steering angle can be detected accurately.

Moreover, the range of the steering angle covered by the output signal of the steering angle sensor is a neutral zone within a predetermined range including at least the neutral position, and the steering angle sensors of the right zone and the left zone respectively adjacent to the neutral zone. The output signal is divided into three zones that show the same value, and in which of these zones the current steering angle is located,
Since the determination is made based on at least the wheel speed difference and the vehicle speed, it becomes possible to uniquely associate the output signal of the steering angle sensor with the steering angle, and even after the ignition switch is turned ON, The steering angle can be detected promptly. Moreover, since the range in which the steering angle is located is only determined based on the wheel speed difference and the vehicle speed, there is an error compared to the case where the steering angle or the neutral position is calculated directly based on these measured values. Has the advantage that Further, since the sensor for determining the neutral position and the reduction gear are not required, the cost can be reduced.

According to the seventh aspect of the invention, since the wheel speed difference is set so that the zone determination is performed at the boundary between the neutral zone and the right zone or the left zone, the zone determination is performed as in the fourth aspect. Will be done reliably.

Furthermore, according to the eighth aspect of the invention, the transition between the adjacent zones is judged when the output signal from the steering angle sensor shows a change larger than a preset reference value. Similar to the fifth aspect of the present invention, it is possible to easily determine the transition between zones, and in this case also, by setting the reference value so that the output change is faster than the steering speed of the human, erroneous determination is prevented. Will be done.

[0036]

[0037]

[0038]

[0039]

[0040]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a vehicle 1 according to this embodiment is a front wheel steering mechanism 10 for steering left and right front wheels 3, 4 as driven wheels by operating a steering handle 2.
A rear wheel steering mechanism 20 that steers the left and right rear wheels 5 and 6 as driving wheels, and is attached to the rear wheel steering mechanism 20.
A steering ratio variable mechanism 30 for setting and changing a steering ratio (= rear wheel steering angle / front wheel steering angle). The rear wheel steering mechanism 20
Is linked to the front wheel steering mechanism 10 via the transmission shaft 7 and is adjusted to a predetermined target rear wheel steering angle according to the front wheel steering angle transmitted via the transmission shaft 7. The rear wheels 5 and 6 are steered.

The vehicle 1 is also equipped with a control unit 40. This control unit 4
0 is a signal from a wheel speed sensor 41 to 44 that detects the rotational speed (wheel speed) of the left and right front and rear wheels 3 to 6, a signal from an analog steering angle sensor 45 attached to the steering handle 2, and a steering handle 2, a signal from a digital steering angle sensor 46, a signal from a steering ratio sensor 47 that detects a steering ratio, a signal from a yaw rate sensor 48 that detects a yaw rate of the vehicle 1, and a signal from an ignition switch 49. Is input to set the steering angle of the steering wheel based on these signals, and the rear wheel steering angle is controlled via the rear wheel steering mechanism 20 by controlling the operation of the steering ratio varying mechanism 30. It has become.

The analog steering angle sensor 45 and the digital steering angle sensor 46 will now be described. The former analog steering angle sensor 45 is constructed as follows, for example.

That is, this analog type steering angle sensor 45
Is a potentiometer-type position sensor, and as shown schematically in FIG. 2, its main body 50 is concentrically arranged so as to surround the outer circumference of the steering shaft 2a that rotates integrally with the steering handle 2, and Body 5
A slider 52 that is brought into contact with a resistor 51 provided on the 0 is fixed to a slip ring 53 that rotates integrally with the steering shaft 2a. And this slip ring 5
The rotation of the steering shaft 2a between one output terminal 55a connected to the slider 54 brought into contact with 3 and the other output terminal 55b branched and connected to the power supply line 57 connected to the input terminal 56. The voltage corresponding to the corner is output. In that case, the steering shaft 2
When the slider 52 is fixed in correspondence with the neutral position of "a" and a voltage of 5V is applied to the input terminal 56, the output voltage Va output between the output terminals 55a and 55b is shown in FIG. 3, for example. Thus, it changes in the range of 0 to 5V according to the steering angle of the steering wheel.

That is, if the counterclockwise direction is positive with respect to the axis of the steering shaft 2a, and the steering handle 2 is rotated counterclockwise from the neutral position, for example,
Along with that, the output voltage Va decreases linearly, 180 °
The output voltage Va suddenly changes from 0V to 5V at the rotated position, and when the steering handle 2 is further rotated, the output voltage Va linearly decreases again to 0V at the position rotated by 540 °. When the steering handle 2 is rotated clockwise from the neutral position, the output voltage Va increases linearly with it, and the output voltage Va suddenly changes from 5V to 0V at the position rotated by 180 °, and the steering wheel When the handle 2 is further rotated, the output voltage Va increases linearly again and becomes 5V at the position rotated by 540 °.

In this embodiment, as shown in the figure, the range in which the steering wheel steering angle is -180 ° to 180 ° is the C zone, and the range in which the steering wheel steering angle is 180 ° to 540 ° is the L zone. , The steering angle of the steering wheel is -180 °-
The range located at 540 ° is set as the R zone.

On the other hand, the latter digital steering angle sensor 46
Is an increment type rotary encoder, and, as schematically shown in FIG. 4, for example, a large number of outer slits 61a ... 61a are arranged at equal intervals in the circumferential direction on the outer peripheral portion of the disk 60 fixed to the steering shaft 2a. The outer slits 61a ... 61a are formed while being formed.
61a ... 61a on the inner side in the radial direction of
A large number of inner slits 61b ... 61b are formed at equal intervals in the circumferential direction while being offset by a predetermined angle. Then, on one side of the disc 60, first and second light emitting diodes 62, 63 for irradiating light to the inner and outer slits 61a, 61a, 61b, 61b are arranged, and the disc 60 is also provided. On the other side, first and second phototransistors 64 and 65 for receiving the light passing through the slits 61a ... 61a, 61b ... 61b are arranged.

In this case, the first and second phototransistors 64 when the steering handle 2 is rotated to the right,
The output waveform of 65 is as shown in FIG. 5, and the output waveforms of the first and second phototransistors 64 and 65 when rotated to the left are as shown in FIG. In this way, since the pattern of the output waveform of the digital steering angle sensor 46 differs depending on the rotating direction of the steering shaft 2,
Steering handle 2 or steering shaft 2
The rotation direction is detected together with the rotation angle of a.

Next, the outline of the rear wheel steering angle control performed by the control unit 40 will be described.

That is, the control unit 40 is
The left and right front wheel speeds Vf1, Vf2 and the left and right rear wheel speeds Vr1, indicated by the signals from the wheel speed sensors 41 to 44, respectively.
The vehicle speed Vb is calculated by arithmetically averaging Vr2, and the steering wheel steering angle (hereinafter referred to as analog steering angle) Θa indicated by the signal from the analog steering angle sensor 45 and the signal from the digital steering angle sensor 46 are calculated. After setting the final steering wheel angle Θ based on the steering wheel steering angle (hereinafter referred to as digital steering angle) Θd, the front wheel steering angle Θf is calculated based on the final steering wheel angle Θ. Then, the target rear wheel steering ratio Ro is calculated based on the vehicle speed Vb, the front wheel steering angle Θf, and the actual yaw rate Yr indicated by the signal from the yaw rate sensor 48, and then the target rear wheel steering ratio Ro and the final steering wheel are used. Rear wheel steering angle Θ calculated based on the steering angle Θ
In order to realize r, a servomotor (not shown) provided in the rear wheel variable mechanism 30 based on the actual turning ratio Rr detected by the turning ratio sensor 47 and the target rear wheel turning ratio Ro. Feedback control.

Next, the control unit 40 calculates the analog steering angle Θa based on the output voltage Va of the analog steering angle sensor 45. Prior to that, the control unit 40 sets the analog steering angle sensor 45. It is adapted to determine which of the neutral zone, the L zone and the R zone shown in FIG. 3 where the current steering angle is located.

That is, the control unit 40 is
In step S1 of the flowchart of FIG. 7, it is determined whether or not the ignition switch 49 is in the ON state, and if the ignition switch 49 is not in the ON state, steps S2, S
3 is executed to set the first and second flags F1 and F2 to 0, respectively, and then the process returns to step S1.

On the other hand, when the control unit 40 determines in step S1 that the ignition switch 49 is in the ON state, it proceeds to step S4 and determines whether the value of the first flag F1 is 1 or not. If it is determined that the value of the 1-flag F1 is not 1, step S5
When it is determined that the value of the first flag F1 is 1, the process proceeds to step S6, and the predetermined zone shift determination process is performed. That is, it is determined which of the neutral zone, the L zone and the R zone shown in FIG. 3 the analog steering angle Θa indicated by the output voltage Va of the analog steering angle sensor 45 is located.

In this case, in this embodiment, the initial zone judgment processing is executed as follows according to the flowchart of FIG.

That is, the control unit 40 is
In step S11, it is determined whether or not the determination rule 1 shown in Table 1 below is established. That is, the vehicle speed Vb obtained from the wheel speeds of the front and rear wheels 3 to 6 is the first predetermined value V1 (for example, 2 km.
/ H) and the second predetermined value (for example, 10 km / h), it is determined whether the value of the reverse flag Fr is set to 0 indicating the non-reverse drive state. Specifically, it is determined whether or not the vehicle is moving forward at a speed of 2 to 10 km / hour.

[0056]

[Table 1] When the control unit 40 determines that the determination rule 1 is satisfied, the process proceeds to step S12, and this time, it is determined whether the determination rule 2 shown in Table 1 is satisfied.
That is, it is determined whether the actual yaw rate Yr indicated by the signal from the yaw rate sensor 48 is higher than a predetermined reference yaw rate Ys. In other words, the value of the yaw rate in the left turning state is positive, and it is determined whether or not the vehicle is in the left turning state. In this case, the reference yaw rate Ys is set with the vehicle speed Vb as a parameter, as shown in Table 2 below, and the reference yaw rate Ys also increases as the vehicle speed Vb increases.

[0057]

[Table 2] When the control unit 40 determines in step S12 that the determination rule 2 is satisfied, that is, when both the determination rule 1 and the determination rule 2 are satisfied, the control unit 40 executes step S13 to make these determinations. While determining whether a predetermined time has passed since the rule was established,
When it is determined that the predetermined time has elapsed, step S1
In step S15, it is determined that the analog steering angle Θa is located in the L zone, and in step S15, 1 is set in each of the first and second flags F1 and F2.

When the control unit 40 determines in step S12 that the determination rule 2 is not satisfied, the control unit 40 proceeds to step S16 and determines whether the determination rule 4 shown in Table 1 is satisfied. . That is,
The left front wheel speed Vf1 is subtracted from the right front wheel speed Vf2,
A value obtained by dividing that value by the front left wheel speed Vf1 is a predetermined value Vo.
(For example, 0.1) is determined. In other words, even in this case, it is determined whether or not the vehicle is turning left. Control unit 40
When it is determined that the determination rule 4 is satisfied, that is, when both the determination rule 1 and the determination rule 4 are determined to be satisfied, in this case also, step S13 is executed and these determination rules are satisfied. It is determined whether or not the predetermined time has elapsed from when the predetermined time has elapsed, and when it is determined that the predetermined time has elapsed, the process proceeds to step S14 and it is determined that the analog steering angle Θa is located in the L zone.

On the other hand, when the control unit 40 determines in step S16 that the determination rule 4 is not satisfied, the control unit 40 proceeds to step S17 and determines whether or not the determination rule 3 shown in Table 1 is satisfied. That is, the actual yaw rate Yr indicated by the signal from the yaw rate sensor 48.
Is smaller than a value obtained by sign-converting the reference yaw rate Yb into a negative value, in other words, it is determined whether the vehicle is making a right turn. Then, when it is determined that the determination rule 3 is satisfied, that is, when both the determination rule 1 and the determination rule 3 are determined to be satisfied, step S18 is executed and a predetermined time has passed since these determination rules were satisfied. When it is determined whether or not the predetermined time has elapsed, the process proceeds to step S19, where the analog steering angle Θa is R
It is determined that the vehicle is located in the zone and step S1
At 9, the first and second flags F1 and F2 are set to 1 respectively.

When the control unit 40 determines in step S17 that the determination rule 3 is not satisfied, the control unit 40 proceeds to step S21 and determines whether the determination rule 5 shown in Table 1 is satisfied. . That is,
Subtract the right front wheel speed Vf2 from the left front wheel speed Vf1,
A value obtained by dividing that value by the right front wheel speed Vf2 is a predetermined value Vo.
Is greater than. In other words, even in this case, it is determined whether or not the vehicle is making a right turn. When the control unit 40 determines that the determination rule 5 is satisfied, that is, when both the determination rule 1 and the determination rule 5 are satisfied, the control unit 40 also executes step S18 and executes these steps. While judging whether a predetermined time has passed since the judgment rule was established,
When it is determined that the predetermined time has elapsed, step S19
Then, it is determined that the analog steering angle Θa is located in the L zone.

When the control unit 40 determines in step S21 that the determination rule 5 is not satisfied, whether or not a predetermined time has elapsed since the determination rule 1 was satisfied by executing step S22. If it is determined that the predetermined time has elapsed, the process proceeds to step S23, where it is determined that the analog steering angle Θa is located in the C zone, and at step S24, the first,
1 is set to each of the second flags F1 and F2.

In this way, the analog steering angle sensor 4
Since it is easy to determine which of the neutral zone, the L zone, and the R zone in the map of FIG. 3 set corresponding to the output voltage Va of No. 5, the current analog steering angle Θa is located. , Ignition switch 4
After turning on 9, the output voltage V of the analog steering angle sensor 45
Based on a, the analog steering angle Θa will be obtained as quickly as possible.

In this case, the analog steering angle Θa is obtained as follows according to the zone determination result.

That is, the control unit 40 is
When it is determined that the analog steering angle Θa is located in the neutral zone, the analog steering angle Θa is calculated according to the following relational expression, and when it is determined that the analog steering angle Θa is located in the L zone, the following relational expression is calculated. Analog steering angle Θa
And it is determined that the analog steering angle Θa is located in the R zone, the analog steering angle Θa is calculated according to the following relational expression.

Θa = 360 (5-Va) / 5-180 ... Θa = 360 (5-Va) / 5 + 180 ... Θa = 360 (5-Va) / 5-540 ... The analog steering angle Θa is uniquely determined with respect to the output signal of the steering angle sensor 45.

Further, the zone shift determination processing is specifically performed as follows according to the flowchart of FIG.

That is, the control unit 40 determines in step S31 whether the analog steering angle Θa is located in the L zone. If it is determined that the analog steering angle Θa is located in the L zone, the process proceeds to step S32 and the analog type The output voltage change amount ΔV per sampling cycle of the steering angle sensor 45 is the first reference value V1 (for example, −500 mV / 10 m).
If it is determined that the output voltage change amount ΔV is smaller than the reference value V1, the process proceeds to step S33 and the analog steering angle Θa shifts from the L zone to the C zone. To determine. In that case, the first reference value V1 is set to be an output voltage change amount that is faster than the human steering speed. This prevents erroneous determination.

On the other hand, when the control unit 40 determines in step S31 that the analog steering angle Θa is not located in the L zone, the control unit 40 proceeds to step S34 and this time determines whether the analog steering angle Θa is located in the C zone. Determine whether or not. If it is determined that the output voltage change amount ΔV per sampling period of the analog steering angle sensor 45 is not the second reference value V2 (eg, 500 mV), the process proceeds to step S35.
/ 10 ms), and when it is determined that the output voltage change amount ΔV is larger than the second reference value V2, the process proceeds to step S36 and the analog steering angle θ
It is determined that a has moved from the R zone to the C zone. Also in this case, the second reference value V2 is set to be the output voltage change amount that is faster than the human steering speed.

When the control unit 40 determines in step S34 that the analog steering angle Θa is located in the C zone, the control unit 40 proceeds to step S37 and outputs the change amount of the output voltage of the analog steering angle sensor 45 per sampling cycle. When it is determined whether ΔV is larger than the second reference value V2 and it is determined that the output voltage change amount ΔV is larger than the second reference value V2, step S3 is performed.
When it is determined that the analog steering angle Θa has shifted from the C zone to the L zone and the output voltage change amount ΔV is not larger than the second reference value V2 in Step 6,
Proceeding to step S39, the output voltage change amount ΔV per sampling period of the analog steering angle sensor 45 is the above first value.
When it is determined whether the output voltage change amount ΔV is smaller than the first reference value V1 by determining whether the analog steering angle Θa is from the C zone to the R zone. It is determined that the process has moved to.

In this way, it is possible to easily determine the transition between zones.

Further, in this embodiment, the final steering wheel steering angle Θ is set as follows according to the flowchart of FIG.

That is, the control unit 40 is
In step T1, it is determined whether or not the value of the second flag F2 is set to 3, and if the value of the flag F2 is not set to 3, the process proceeds to step T2 and this time the value of the second flag F2. Is set to 2 or not. When it is determined that the value of the second flag F2 is not 2, the process proceeds to step T3, it is determined whether or not the value of the second flag F2 is set to 1, and the flag F
When it is determined that the value of 2 is set to 1, the process proceeds to step T4, where the analog steering angle Θa at that time is set as the steering angle reference value Θb of the digital steering angle sensor 46, and at step T5 2 The value of the flag F2 is set to 2.

When the control unit 40 determines in step T2 that the value of the second flag F2 is set to 2, the control unit 40 proceeds to step T6 and determines whether the digital steering angle sensor 46 is out of order. If it is determined that there is no failure, step T
7 is executed, the value obtained by subtracting the steering angle reference value Θb from the digital steering angle Θd indicated by the signal from the digital steering angle sensor 46 is set as the final steering wheel steering angle Θ, and in step T8, for example, the left and right front wheel wheels are set. It is determined whether the speed difference ΔVf is smaller than the predetermined value α. It is determined whether or not the vehicle is in a straight traveling state.

When the control unit 40 determines in step T8 that the front and rear wheel speed difference ΔVf is smaller than the predetermined value α, the control unit 40 proceeds to step T9 and determines whether or not the final steering wheel steering angle Θ has converged to zero. If it is not converged to 0, it is determined in step T10 whether or not the final steering wheel steering angle Θ is larger than 0. If it is larger than 0, in step T11 the final steering wheel steering angle Θ is determined.
The value obtained by subtracting a small amount δ (> 0) from the above is replaced with the final steering wheel steering angle Θ, and if the final steering wheel steering angle Θ is not greater than 0, the value obtained by adding a small amount δ to the final steering wheel steering angle Θ in step T12. Is replaced with the final steering wheel steering angle Θ.
As a result, the final steering wheel steering angle Θ is corrected so as to gradually converge to zero.

On the other hand, when the control unit 40 determines in step T6 that the digital steering angle sensor 46 is out of order, the control unit 40 proceeds to step T13 and sets the value of the second flag F2 to 3.

Further, when the control unit 40 determines in step T1 that the value of the second flag F2 is set to 3, the control unit 40 proceeds to step T14 and sets the analog steering angle Θa as the final steering wheel steering angle Θ. . In this way, when the digital steering angle sensor 46 fails, it is switched to the analog steering angle sensor 45, so that the fail-safe property is improved.

Next, a second embodiment of the initial zone determination processing will be described with reference to the flowchart of FIG.

That is, the control unit 40 is
In step S11 ', it is determined whether or not the determination rule 1 shown in Table 1 above is established. When the control unit 40 determines that the determination rule 1 is satisfied, the control unit 40 proceeds to step S12 ′, and this time determines whether or not the determination rule 2 shown in Table 1 above is satisfied. When it is determined that the determination rule 2 is satisfied, the process proceeds to step S13 ′ to determine whether or not the determination rule 4 shown in Table 1 is satisfied, and the determination rule 4 is also satisfied. When it is determined that the judgment rule 1, the judgment rule 2 and the judgment rule 4 are all satisfied, the step S14 ′ is executed and a predetermined time elapses after the judgment rules are satisfied. If it is determined that the predetermined time has elapsed, the process proceeds to step S15 ′, and the analog steering angle Θa
Is determined to be located in the L zone, and 1 is set to the first and second flags F1 and F2 in step S16 '.

When the control unit 40 determines in step S12 'that the determination rule 2 is not established, the control unit 40 proceeds to step S17' and returns to table 1 above.
It is determined whether the determination rule 3 shown in is satisfied. When determining that the determination rule 3 is satisfied, the control unit 40 proceeds to step T18 ′ and determines whether the determination rule 5 shown in Table 1 above is satisfied. Then, when it is determined that the determination rule 5 is also satisfied, that is, when it is determined that the determination rule 1, the determination rule 3, and the determination rule 5 are satisfied, step S19 ′ is executed to execute these determination rules. It is determined whether or not a predetermined time has elapsed since the condition was established, and when it is determined that the predetermined time has elapsed, the process proceeds to step S20 ′ and it is determined that the analog steering angle Θa is located in the L zone. Together with step S2
At 1 ', 1 is set to each of the first and second flags F1 and F2.

Further, when the control unit 40 determines in step S17 'that the determination rule 3 is not established, the control unit 40 proceeds to step S22' and determines whether or not the determination rule 4 is established. When the control unit 40 determines that the determination rule 4 is not established, the control unit 40 proceeds to step S23 ′ to determine whether or not the determination rule 5 is established this time, and the determination rule 4 is also not established. If it is determined that step S24 'is executed to determine whether or not a predetermined time has elapsed since the determination rule 1 was established, and if it is determined that the predetermined time has elapsed, the process proceeds to step S25'. It is determined that the analog steering angle Θa is located in the C zone, and step S2
At 6 ', 1 is set to each of the first and second flags F1 and F2.

Therefore, also in this embodiment, the current analog steering angle Θa is set in any of the neutral zone, the L zone and the R zone in the map of FIG. 3 set corresponding to the output voltage of the analog steering angle sensor 45. Since it can be easily determined whether or not the position of the analog steering angle sensor 4 is turned on after the ignition switch 49 is turned on.
The analog steering angle Θa can be obtained as quickly as possible based on the output voltage of No. 5.

According to this embodiment, the zone determination is performed based on the yaw rate, the wheel speed difference between the left and right wheels, and the vehicle speed. Therefore, the zone determination can be performed more accurately than in the first embodiment. become.

[0083]

As described above, in any of the first to fifth inventions of the present application, the potentiometer-type analog steering angle sensor is attached, and the steering angle sensor and the steering handle are one-to-one. Since the steering angles are linked and linked, the turning angle can be accurately detected.

In this case, the range of the steering angle covered by the output signal of the steering angle sensor is defined as a neutral zone within a predetermined range including at least the neutral position, and the steering angles of the right zone and the left zone respectively adjacent to the neutral zone. The output signal of the sensor is divided into three zones each having the same value, and which zone of the zones the current steering angle is located in is determined based on at least the yaw rate and the vehicle speed. Therefore, the output signal of the rudder angle sensor can be uniquely associated with the rudder angle, and the rudder angle can be detected as quickly as possible even after the ignition switch is turned on. Moreover, since the range in which the steering angle is located is only determined based on the yaw rate and the vehicle speed, there is less error than when the steering angle or neutral position is calculated directly based on these measured values. Has the advantage that Further, since the sensor for determining the neutral position and the reduction gear are not required, the cost can be reduced.

Further, according to the second aspect of the invention, for example, the zone determination is performed by comparing the actual yaw rate indicated by the output from the yaw rate sensor with the reference yaw rate preset according to the vehicle speed. The zone determination will be performed accurately.

According to the third aspect of the invention, the zone determination is performed based on the wheel speed difference between the left and right wheels of the vehicle, the yaw rate, and the vehicle speed. Therefore, the zone determination can be performed more accurately.

According to the fourth aspect of the invention, the yaw rate or the wheel speed difference is set so that the zone determination is made at the boundary between the neutral zone and the right zone or the left zone. Therefore, for example, the actual yaw rate is the reference yaw rate. When it is larger than the above, the right zone is judged, and when the actual yaw rate is smaller than the reference yaw rate, it is judged as the neutral zone, so that the zone judgment is surely made.

Further, according to the fifth aspect of the invention, when the output signal from the steering angle sensor shows a change larger than the preset reference value, the transition between the adjacent zones is judged. It is possible to easily determine the transition between zones and prevent the erroneous determination by setting the reference value so that the output change is faster than the steering speed of a person.

Further, in any of the sixth to eighth inventions of the present application, a potentiometer-type analog steering angle sensor is additionally provided, and the steering angle sensor and the steering wheel are interlocked at a rotation ratio of 1: 1. Therefore, the rudder angle is accurately detected.

Moreover, the range of the steering angle covered by the output signal of the steering angle sensor is a neutral zone within a predetermined range including at least the neutral position, and the steering angle sensors of the right zone and the left zone respectively adjacent to the neutral zone. The output signal is divided into three zones that show the same value, and in which of these zones the current steering angle is located,
Since the determination is made based on at least the wheel speed difference and the vehicle speed, it becomes possible to uniquely associate the output signal of the steering angle sensor with the steering angle, and even after the ignition switch is turned ON, The steering angle can be detected promptly. Moreover, since the range in which the steering angle is located is only determined based on the wheel speed difference and the vehicle speed, there is an error compared to the case where the steering angle or the neutral position is calculated directly based on these measured values. Has the advantage that Further, since the sensor for determining the neutral position and the reduction gear are not required, the cost can be reduced.

According to the seventh aspect of the invention, the wheel speed difference is set so that the zone determination is made at the boundary between the neutral zone and the right zone or the left zone. Will be done reliably.

Further, according to the eighth aspect of the invention, the transition between the adjacent zones is judged when the output signal from the steering angle sensor shows a change larger than a preset reference value. Similar to the fifth aspect of the present invention, it is possible to easily determine the transition between zones, and in this case also, by setting the reference value so that the output change is faster than the steering speed of the human, erroneous determination is prevented. Will be done.

[0093]

[0094]

[0095]

[0096]

[Brief description of drawings]

FIG. 1 is a control system diagram of a vehicle steering system according to an embodiment.

FIG. 2 is a schematic diagram showing a potentio-type analog steering angle sensor.

FIG. 3 is a characteristic diagram showing a relationship between an output voltage of an analog steering angle sensor and a steering wheel steering angle.

FIG. 4 is a schematic view showing a rotary encoder type digital steering angle sensor.

FIG. 5 is a waveform diagram showing an output waveform of the digital steering angle sensor when the steering handle rotates to the right.

FIG. 6 is a waveform diagram showing an output waveform of the digital steering angle sensor when the steering handle is also rotated counterclockwise.

FIG. 7 is a flowchart showing a main routine of analog steering angle zone determination processing.

8 is a flowchart showing a subroutine of initial zone determination processing in the flowchart of FIG.

9 is a flowchart showing a subroutine of zone shift determination processing in the flowchart of FIG.

FIG. 10 is a flowchart showing a setting process of a final steering wheel steering angle.

FIG. 11 is a flowchart showing a second embodiment of the initial zone determination processing.

[Explanation of symbols]

1 vehicle 2 steering wheel 40 control unit 41-44 Wheel speed sensor 45 Analog type rudder angle sensor 46 Digital rudder angle sensor 48 Yaw rate sensor

─────────────────────────────────────────────────── ───Continued from the front page (56) References JP-A 2-40504 (JP, A) JP-A 2-218909 (JP, A) JP-A 4-318414 (JP, A) JP-A 4- 348216 (JP, A) JP 6-18255 (JP, A) JP 5-215542 (JP, A) JP 5-85369 (JP, A) JP 3-45469 (JP, A) JP-A 1-172057 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01B 7/30 G01B 21/22

Claims (8)

(57) [Claims] 1. A steering angle detecting device for a vehicle, wherein a potentiometer type analog steering angle sensor is attached to a steering wheel, wherein the steering angle sensor and the steering wheel are interlocked at a rotation ratio of 1: 1. In addition, the yaw rate detecting means for detecting the yaw rate of the vehicle, the vehicle speed detecting means for detecting the vehicle speed of the vehicle, and the range of the steering angle covered by the output signal of the steering angle sensor are at least a predetermined range including the neutral position. The current steering angle is divided into three zones in which the output signals of the steering angle sensors of the neutral zone within the range, the right zone and the left zone respectively adjacent to the neutral zone show the same value, and the current steering angle is among these zones. Zone determination means for determining in which zone the vehicle is located based on the yaw rate detected by each of the detection means and the vehicle speed is provided. And a turning angle detecting device for a vehicle. 2. The zone determination means is configured to perform zone determination by comparing an actual yaw rate indicated by a signal from the yaw rate detection means with a reference yaw rate preset according to a vehicle speed. The turning angle detection device for a vehicle according to claim 1, wherein the turning angle detection device is a vehicle steering angle detection device. 3. A wheel speed detecting means for detecting a wheel speed is provided, and the zone judging means judges a zone on the basis of a left / right wheel speed difference detected by the wheel speed detecting means, a yaw rate and a vehicle speed. The steering angle detection device for a vehicle according to claim 1, wherein the steering angle detection device is configured to perform the following. 4. The yaw rate or the wheel speed difference is set so that the zone determination is performed at the boundary between the neutral zone and the right zone or the left zone.
4. The turning angle detecting device for a vehicle according to claim 3. 5. A zone shift judging means for judging shift between adjacent zones when an output signal from the steering angle sensor shows a change larger than a preset reference value. The steering angle detection device for a vehicle according to any one of claims 1 to 4. 6. A turning angle detecting device for a vehicle, wherein a potentiometer type analog rudder angle sensor is attached to a steering wheel, wherein the rudder angle sensor and the steering wheel are interlocked at a rotation ratio of 1: 1. Along with, the wheel speed detection means for detecting the wheel speed of the vehicle, the vehicle speed detection means for detecting the vehicle speed of the vehicle, the range of the steering angle covered by the output signal of the steering angle sensor, at least at the neutral position. The present steering angle is divided into three zones in which the output signals of the steering angle sensors of the neutral zone within a predetermined range including the right zone and the left zone respectively adjacent to the neutral zone show the same value, and the current steering angle is within these zones. It is provided with zone determination means for determining which one of the zones is located based on the vehicle speed and the wheel speed difference between the left and right wheels detected by the detection means. A characteristic vehicle turning angle detection device. 7. The turning angle detecting device for a vehicle according to claim 6, wherein the wheel speed difference is set so that the zone determination is performed at the boundary between the neutral zone and the right zone or the left zone. . 8. A zone shift judging means for judging shift between adjacent zones when an output signal from the steering angle sensor shows a change larger than a preset reference value. The steering angle detection device for a vehicle according to claim 6 or 7.