JP5477130B2 - Steering angle detection device and steering angle detection method - Google Patents

Description

  The present invention relates to a steering angle detection device and a steering angle detection method for detecting a steering angle of a steering wheel of a vehicle.

There are steering stability and vehicle motion characteristics as evaluation items for evaluating the performance of tires mounted on vehicles, and the steering angle of the steering wheel is an important measurement item in evaluating these steering stability and motion characteristics. is there.
Conventionally, a dedicated steering angle meter or steering angular force meter is incorporated, and a steering wheel developed for each vehicle type is prepared. After the steering wheel provided on the vehicle to be measured is removed, the dedicated steering wheel is used. The wheel is attached to the vehicle.
In addition, it is conceivable to detect a steering angle by incorporating an angle measuring device for measuring a rotation angle as shown in Patent Document 1 into a steering mechanism.
Alternatively, as shown in Patent Document 2, it has been proposed to use a rotation angle detection device incorporated in the steering mechanism from the beginning.

Japanese Patent Laid-Open No. 2003-166821 JP 2000-066552 A

However, when using a dedicated steering wheel in which the steering angle meter or steering angular force meter described above is used, it is a matter of course that the installation work on the vehicle becomes complicated and time-consuming. A dedicated steering wheel must be prepared, which is disadvantageous in facilitating measurement work and reducing costs.
Further, even when using the devices disclosed in Patent Documents 1 and 2, since the work of mounting these devices on a vehicle is complicated and time-consuming, there are disadvantages in facilitating measurement work and reducing costs. is there.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a steering angle detection device and a steering angle detection method that are advantageous in facilitating measurement work and reducing costs.

In order to achieve the above object, the present invention provides a steering angle detection for detecting a steering angle of a steering wheel of a vehicle provided with a non-circular shape portion extending around the rotation axis when viewed from the rotation axis direction. An inclined surface that is arranged along the outer periphery of the shape portion and monotonously increases from the lowest bottom to the highest top along the outer periphery of the shape portion; A plurality of detection protrusions each including a plurality of detection protrusions, each of which includes a standing surface connecting the lowermost portion of the adjacent detection protrusion and the uppermost portion of the inclined surface and extending along a radial direction of the rotation axis; Displacement amount detecting means having a displacement amount sensor for detecting a displacement amount in the radial direction of the rotating shaft of the inclined surface that changes with rotation of the steering wheel at a location; and for one rotation of the steering wheel. A plurality of steering angles which are actually measured, and the data table creation means for creating a data table correlating the detected amount of displacement by the displacement amount detecting means in correspondence with each of the steering angle of the plurality of the data table Each time a new steering angle is specified by the steering angle detection means, a data table means for storing data, a steering angle detection means for specifying a steering angle from the data table and outputting steering angle data indicating the steering angle, and The steering angle holding means for updating and holding the steering angle as the nearest steering angle, and the data table creation means includes a plurality of discretely measured steering angles, and each of the plurality of steering angles. An intermediate data table corresponding to the detected displacement amount is created, and interpolation processing is performed on the steering angle and displacement amount of the intermediate data table to obtain a data having an arbitrary resolution. Create a data table, the specific of the steering angle by the steering angle detecting means, a displacement amount detected by the displacement amount detecting means is made based on said last steering angle, it is characterized.
Further, the present invention is a steering angle detection method for detecting a steering angle of a steering wheel of a vehicle provided with a non-circular shape portion extending around the rotation axis when viewed from the rotation axis direction, Inclined surfaces that are arranged along the outer periphery of the shape portion and monotonously increase from the lowest portion along the outer periphery of the shape portion to the highest portion with the highest height, and the adjacent detection protrusions A plurality of detection projections each including a rising surface connecting the lowermost portion and the uppermost portion of the inclined surface and extending along a radial direction of the rotating shaft, and the steering wheel at a predetermined measurement location. A displacement amount detecting step for detecting a displacement amount of the inclined surface in the radial direction of the rotating shaft, which changes with rotation of the steering wheel, a plurality of steering angles measured over one rotation of the steering wheel, Showing the amount of displacement detected by the displacement amount detecting means corresponding to each of the steering angle and the data table creation step of creating a data table that associates the specified the steering angle of the steering angle from the data table A steering angle detecting step for outputting steering angle data; and a nearest steering angle holding step for updating and holding the steering angle as the nearest steering angle each time a new steering angle is specified by the steering angle detecting means. The steering angle is specified by the steering angle detection step based on the displacement amount detected in the displacement amount detection step and the most recent steering angle.

A plurality of detection protrusions having an inclined surface and an upright surface are provided along the outer periphery of the shape portion of the steering wheel, the displacement amount of the inclined surface in the radial direction of the rotation axis is detected, and the steering angle and the displacement amount are associated with each other. The steering angle is identified from the data table and the steering angle data indicating the steering angle is output, and the steering angle is identified based on the detected displacement amount and the most recent steering angle.
Therefore, it is not necessary to prepare an expensive dedicated steering wheel, and complicated work such as replacement of the dedicated steering wheel or installation of a dedicated measuring device in the steering mechanism of the vehicle is not required, thus facilitating measurement work. This is advantageous in reducing cost and cost.

It is explanatory drawing which shows the structure of the steering angle detection apparatus 10 which concerns on embodiment. It is a block diagram which shows the structure of the control system of the steering angle detection apparatus 10 which concerns on embodiment. It is a front view which shows the shape of the non-circular shaped part 4. FIG. FIG. 6 is a front view showing a state in which a plurality of detection protrusions 12 are arranged on the outer periphery of a non-circular shaped portion 4. It is a perspective view of the adhesive tape 20 provided with the some protrusion 12 for a detection. It is explanatory drawing explaining the detection operation | movement of the displacement amount d in the radial direction of the rotating shaft of 12 A of inclined surfaces by the displacement amount detection means. It is explanatory drawing which shows the relationship between the displacement amount d in the radial direction of the rotating shaft of 12 A of inclined surfaces detected by the displacement amount detection means 14, and steering angle (theta). It is explanatory drawing which shows the relationship between the displacement amount d detected by the displacement amount detection means 14, and steering angle (theta). It is a flowchart which shows the creation process of the data table in the steering angle detection apparatus 40 which concerns on embodiment. It is an operation | movement flowchart of the steering angle detection apparatus 40 which concerns on embodiment. Explanatory drawing which shows the relationship between the displacement amount d detected by the displacement amount detection means 14 and steering angle (theta) when the positional relationship of 12 A of inclined surfaces of the protrusion 12 for detection, and the standing surface 12B is reverse to FIG. It is. It is explanatory drawing which shows the relationship between the displacement amount d and steering angle (theta) when shape part 2D is comprised by the circular shape part.

Embodiments of a vehicle steering angle detection device and a steering angle detection method according to the present invention will be described below with reference to the drawings.
First, a steering wheel 2 whose steering angle is detected by the steering angle detection device 10 of the present embodiment will be described with reference to FIG.
The steering wheel 2 includes an annular rim portion 2A operated by a driver, a central case portion 2B disposed in the center inside the rim portion 2A, and a plurality of rim portions 2A and the central case portion 2B. Spoke part 2C.
A shape portion 2D is integrally provided on the back surface of the central case portion 2B, and a boss portion 2E is integrally provided on the back surface of the shape portion 2D. The boss portion 2E is coupled to a steering shaft (not shown).
In the present embodiment, the shape portion 2D is composed of a non-circular shape portion 4 that exhibits a non-circular shape around the rotation axis when viewed from the steering shaft direction, that is, the rotation axis direction.
The shape portion 2D may be formed of a circular shape portion that is concentric with the rotation axis.

Next, the steering angle detection device 10 of the present embodiment will be described.
As shown in FIG. 1, the steering angle detection device 10 includes a plurality of detection protrusions 12, a displacement amount detection means 14, an operation unit 16, and an ECU 18.

As shown in FIGS. 1 and 4, the plurality of detection protrusions 12 are arranged along the outer periphery of the non-circular shape portion 4, and in the present embodiment, the plurality of detection protrusions 12 have the same shape and the same size. It is.
As shown in FIG. 4, each detection projection 12 includes an inclined surface 12A and an upright surface 12B.
The inclined surface 12A monotonously increases along the outer periphery of the non-circular shaped portion 4 from the lowest lowest part to the highest highest part.
The standing surface 12B connects the lowermost part of the adjacent detection projection 12 and the uppermost part of the inclined surface 12A and extends along the radial direction of the rotation axis.

In the present embodiment, as shown in FIG. 4, the adhesive tape 20 provided with a plurality of detection projections 12 as shown in FIG. 5 is attached to the outer periphery of the non-circular shaped portion 4 shown in FIG. A plurality of detection projections 12 are arranged on the outer periphery of the circular shaped portion 4.
As shown in FIG. 5, the adhesive tape 20 has a strip shape. A plurality of detection protrusions 12 are formed along the longitudinal direction of the adhesive tape 20 on the surface 20B of the adhesive tape 20 opposite to the adhesive surface 20A.
By using such an adhesive tape 20, a plurality of detection protrusions 12 can be easily provided on the outer periphery of the shape portion 20D, which is advantageous in facilitating the steering angle measurement operation.

Further, the height h of the rising surface 12B of the detection protrusion 12, in other words, the dimension h of the rising surface 12B along the radial direction of the rotating shaft is in the range of 0.5 to 20 mm, which will be described later. It is preferable for facilitating the attaching operation of the adhesive tape 20 while ensuring the detection accuracy of the steering angle detected by the detecting means 30 (FIG. 2).
That is, if the dimension of the upright surface 12B is less than the above range, the change amount of the displacement amount detected by the displacement amount detection means 14 with respect to the change amount of the steering angle is too small, which is disadvantageous in ensuring the detection accuracy of the steering angle. It becomes.
If the size of the rising surface 12B exceeds the above range, the outer shape of the detection projection 12 becomes too large, which may hinder driving operations and the like, and work for attaching the adhesive tape 20 to the outer periphery of the non-circular shaped portion 4 There is a disadvantage that sex is reduced.

The displacement amount detection means 14 detects the displacement amount d in the radial direction of the rotation axis of the inclined surface 12A that changes with the rotation of the steering wheel 2 at a predetermined measurement location, and generates a detection signal corresponding to the displacement amount d. This is supplied to the ECU 18.
The displacement amount detection means 14 is preferably a non-contact type displacement amount sensor because the displacement amount d can be detected without contacting the detection projection 12.
In the present embodiment, the displacement amount detection means 14 is constituted by a non-contact displacement amount sensor fixed at a location in the vehicle compartment facing the plurality of detection protrusions 12.
As such a non-contact displacement sensor, the reflected light reflected by the object is received by irradiating the object with laser light as detection light, and the displacement is based on the incident angle of the received reflected light. Various conventionally known displacement amount sensors such as a laser displacement amount sensor that detects the distance between the sensor and the object and detects the displacement amount based on the distance can be used.
The displacement amount detection means 14 may be fixed to the passenger compartment by, for example, fixing it to an instrument panel located in front of the driver's seat via an attachment member (not shown). Means are arbitrary.

FIG. 6 is an explanatory diagram for explaining the operation of detecting the displacement d in the radial direction of the rotation axis of the inclined surface 12A by the displacement detection means 14, and FIG. 7 shows the rotation axis of the inclined surface 12A detected by the displacement detection means 14. It is explanatory drawing which shows the relationship between the displacement amount d in radial direction, and steering angle (theta).
As shown in FIG. 6, when the steering wheel 2 is rotated, each inclined surface 12 </ b> A is rotated about the rotation axis O.
In the figure, θ represents the steering angle of the steering wheel 2. Further, d indicates the displacement amount in the radial direction of the rotation axis of the inclined surface 12A detected by the displacement amount detection means 14.

FIG. 7 shows the detection by the displacement detection means 14 when the steering wheel 2 is rotated once, in other words, when the steering wheel 2 is rotated 360 degrees, for example, clockwise from the neutral position of 0 degrees. The amount of displacement d is shown.
The neutral position of the steering wheel 2 corresponds to a case where the vehicle is driven straight.
That is, the displacement amount d when the steering angle θ is changed from 0 degree to 360 degrees is shown.
As shown in FIG. 7, the waveform S0 indicating the displacement d is obtained by adding the waveform S1 indicated by a broken line corresponding to the shape of the outer periphery of the non-circular shape portion 4 and the waveform S2 corresponding to the shape of the inclined surface 12A. It will be a thing.

As shown in FIG. 1, the operation unit 16 supplies a signal generated in accordance with a user operation to the ECU 18.
In the present embodiment, the operation unit 16 includes a reference angle setting switch 22.
The function of the reference angle setting switch 22 will be described later.

As shown in FIG. 1, the ECU 18 includes a CPU 18A, a first ROM 18B that stores a control program, a second ROM 18C that can rewrite data, a RAM 18D that provides a working area, an interface unit 18E, and the like. Is constituted by a microcomputer connected by a bus.
The interface unit 18E serves as an interface between the displacement amount detection means 14 and the operation unit 16.
As shown in FIG. 2, the ECU 18 includes data table means 26, data table creation means 28, steering angle detection means 30, and nearest steering angle holding means 32.
The data table means 26 is constituted by the second ROM 18C.
The data table creation means 28, the steering angle detection means 30, and the latest steering angle holding means 32 are realized by the CPU 18A executing the control program.

The data table means 26 is data in which a plurality of steering angles actually measured over one rotation of the steering wheel 2 are associated with displacement amounts detected by the displacement amount detection means 14 corresponding to each of the plurality of steering angles. The table is stored.
As shown in FIG. 8, this data table includes data in which the displacement amount d and the steering angle θ are associated with each other.

  The data table creation means 28 creates the data table and stores it in the data table means 26.

The steering angle detection means 30 is for specifying the steering angle from the data table of the data table means 26 and outputting steering angle data indicating the steering angle.
The identification of the steering angle by the steering angle detection means 30 is based on the displacement amount d detected by the displacement amount detection means 14 and the most recent (previous) steering angle θ ₀ held by the nearest steering angle holding means 32 described below. And based on
The output steering angle data is supplied to an external device (not shown) connected via the interface unit 18E of the ECU 18, for example, a data logger, accumulated in the data logger, and used for various evaluations.
The form of the output steering angle data may be a digital signal or an analog signal.

The nearest steering angle holding means 32 updates and holds the steering angle θ as the nearest steering angle θ ₀ each time a new steering angle θ is specified by the steering angle detection means 30.

Next, the operation of the steering angle detection device 10 will be described with reference to the flowcharts of FIGS.
First, as shown in FIG. 9, prior to the detection of the steering angle θ by the steering angle detection device 10, a process of creating a data table in advance and storing it in the data table means 26 is executed.
That is, the user attaches a protractor to the steering wheel 2 so that the steering angle θ of the steering wheel 2 can be measured (step S10).
Next, the user connects a personal computer as an external device for data input to the interface unit 18E (step S12).
The user operates the personal computer every time the steering wheel 2 is rotated from the neutral position by a predetermined angle, for example, 2 degrees, for example, clockwise from the neutral position using the protractor. Thus, the actually measured steering angle θ is supplied to the data table creating means 28 via the personal computer (step S14).

  Each time the data table creation unit 28 receives the actually measured steering angle θ, the data table creation unit 28 generates data that associates the actually measured steering angle θ with the displacement amount d detected by the displacement amount detection unit 14 at that time. An intermediate data table is created by storing in the data table means 26 (step S16). Specifically, the steering angle θ of the intermediate data table is an integral multiple of a predetermined angle. In this example, the steering angle θ = 0 degree, 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees, It is a discrete value of 30 degrees, ..., 360 degrees.

Next, the data table creation means 28 determines whether or not the actually measured steering angle θ supplied from the personal computer has reached 360 degrees (step S18).
If the determination result of step S18 is negative, the data table creation unit 28 returns to step S14.
If the determination result in step S18 is affirmative, the data table creation unit 28 finishes creating the intermediate data table.
In the intermediate data table, since the steering angle θ is a discrete value, and in this example, the steering angle θ is every 5 degrees, the resolution of the steering angle θ remains low.
Therefore, in order to detect the steering angle θ with higher resolution, the data table creation means 28 performs the interpolation process on the steering angle θ and the displacement amount d of the intermediate data table to thereby reduce the resolution of the steering angle θ and the displacement amount d. For example, a data table having a higher resolution of the steering angle θ is created (step S20). Note that various known interpolation methods can be used as the interpolation processing.

Next, a data table is created as follows based on the interpolated steering angle θ and displacement d (step S22).
That is, normally, the steering wheel 2 rotates one or more times clockwise with respect to the neutral position and rotates one or more times counterclockwise with respect to the neutral position.
Therefore, if the steering angle θ corresponding to the neutral position is 0 degree, the steering angle θ in the clockwise direction is a positive value, and the steering angle θ in the counterclockwise direction is a negative value, the steering angle θ is −180 degrees to It changes beyond the range of 180 degrees.
Therefore, it is necessary that the steering angle θ and the displacement amount d constituting the data table correspond to the entire rotation range of the steering wheel 2.
As described above, the displacement d has a repetitive waveform with the steering angle θ = 360 degrees as one cycle. Therefore, the steering angle θ = 0 degrees in the range where the steering angle θ is less than 0 degree and the range where it exceeds 360 degrees. A data table may be created by repeatedly using data of the displacement amount d corresponding to ˜360 degrees.
If a data table corresponding to the entire rotation range of the steering wheel 2 is created, the data table is stored in the data table means 26 (step S24).
Here, the data table is data in which the displacement amount d and the steering angle θ are associated as shown in FIG.
This completes the process of creating the data table and storing it in the data table means 26.

Next, the detection operation of the steering angle θ by the steering angle detection device 10 will be described.
It is assumed that the steering wheel 2 is positioned in a substantially neutral position in advance, and therefore the steering angle θ is a value in the vicinity of 0 degrees.
In this state, when the user operates the reference angle setting switch 22, a reference angle setting signal is supplied to the steering angle detection means 30 (step S30).

  When the steering angle detection unit 30 receives the reference angle setting signal, the steering angle detection unit 30 refers to the data table of the data table unit 26 and matches the displacement amount d supplied from the displacement amount detection unit 14 in the vicinity of the steering angle θ = 0 degrees. The displacement amount d on the data table is specified. Then, the steering angle θ corresponding to the specified displacement amount d is specified from the data table, and steering angle data indicating the specified steering angle θ (reference angle) is output (step S32).

Last steering angle holding means 32, and holds the updated steering angle theta specified in step S32 as the last steering angle theta ₀ (step S34).
The steering angle detection means 30 refers to the data table based on the detected displacement amount d and the most recent steering angle θ ₀ , identifies the current steering angle d, and corresponds to the identified steering angle d. Steering angle data is output (step S36).
Thereafter, returning to step S34, the same processing is repeated.

Here, the operation of the steering angle detection means 30 in step S36 will be described in detail.
When the steering wheel 2 is rotated clockwise or counterclockwise and the steering angle θ is changed, the displacement d supplied from the displacement detection means 14 increases or decreases along the waveform shown in FIG. .
As shown in FIG. 8, the waveform S0 indicating the relationship between the displacement d and the steering angle θ has a shape corresponding to the inclined surface 12A and the standing surface 12B of the detection projection 12.
That is, the waveform S0 is configured by repeating the unit waveform W composed of the inclined portion α and the straight portion β.
That is, the inclined portion α is a portion where the displacement d increases monotonously from the minimum value as the steering angle θ increases.
The straight line portion β is a portion that connects the minimum value of the adjacent inclined portion α and the maximum value of the inclined portion α and is parallel to the vertical axis that indicates the displacement d.

In the present embodiment, when the steering wheel 2 is rotated in the clockwise direction, the steering angle θ changes in the positive direction. Therefore, the displacement amount d continuously changes in a direction increasing along the inclined portion α. Eventually, when the displacement amount d reaches the maximum value, the displacement amount d instantaneously changes to the minimum value along the straight line portion β, and again, the displacement amount d continuously changes in the increasing direction along the inclined portion α.
In this case, as long as the steering wheel 2 continues to rotate in the clockwise direction, the displacement d repeats the above-described change.
On the other hand, when the steering wheel 2 is rotated counterclockwise, the steering angle θ changes in the negative direction, so that the displacement d continuously changes in a direction that decreases along the inclined portion α. Eventually, when the displacement amount d reaches the minimum value, the displacement amount instantaneously changes to the maximum value along the straight line portion β, and the displacement amount d continuously changes again in a decreasing direction.
In this case, as long as the steering wheel 2 continues to rotate counterclockwise, the displacement d repeats the above-described change.
In other words, on one inclined portion α, the displacement amount d increases as the steering angle θ increases, and the displacement amount d decreases as the steering angle θ decreases.

On the other hand, as apparent from FIG. 8, a plurality of steering angles θ correspond to the same displacement amount d, so that the true steering angle θ is not specified only by specifying the displacement amount d.
Therefore, in the present embodiment, the steering angle detection means 30 corresponds to which inclination part α of the plurality of inclination parts α constituting the waveform S0 on the data table, the displacement amount d currently detected. the dolphin, identified based on the most recent of the steering angle θ _0.
Then, the steering angle detection means 30 specifies the steering angle θ corresponding to the currently detected displacement amount d as the true steering angle θ by using the specified inclined portion α of the waveform S0. .
Further, in the present embodiment, as described above, on one inclined portion α, the displacement amount d increases continuously when the steering angle θ increases, and the displacement amount d increases continuously when the steering angle θ decreases. The relationship will decrease.
Accordingly, as long as the inclined portion α is specified, two or more steering angles θ do not correspond to one displacement d, and the displacement d and the steering angle θ always have a one-to-one relationship.
Therefore, the true steering angle θ can be accurately specified based on the displacement amount d.
When the positional relationship between the inclined surface 12A and the standing surface 12B of the detection projection 12 is opposite to that in FIG. 4, the positional relationship between the inclined portion α and the straight portion β in the waveform S0 is also opposite to that in FIG. Specifically, the positional relationship is as shown in FIG.
In this case, on one inclined portion α, the displacement d decreases continuously when the steering angle θ increases, and the displacement d increases continuously when the steering angle θ decreases.
Accordingly, as long as the inclined portion α is specified, two or more steering angles θ do not correspond to one displacement d, and the displacement d and the steering angle θ always have a one-to-one relationship. Is the same as in the case of FIG.

As described above, according to the present embodiment, the plurality of detection protrusions 12 including the inclined surface 12A and the standing surface 12B are provided along the outer periphery of the shape portion 2D of the steering wheel 2, and the rotation shaft of the inclined surface 12A is provided. Is detected, a steering angle θ is identified from a data table in which the steering angle θ and the displacement amount d are associated, and steering angle data indicating the steering angle θ is output to identify the steering angle θ. Is performed based on the detected displacement amount d and the most recent steering angle θ ₀ .
Accordingly, since it is sufficient to install the displacement amount detection means 14 for detecting the displacement amount d in the radial direction of the rotation axis of the inclined surface 12A, for example, in the passenger compartment, it is advantageous in facilitating measurement work and reducing costs. .
That is, conventionally, it is necessary to replace the steering wheel of the vehicle with a dedicated steering wheel having a steering angle meter or a steering angular force meter, or to incorporate a dedicated measuring device into the steering mechanism of the vehicle.
Therefore, in the former case, it is a matter of course that the replacement work of the steering becomes complicated, and there is an inconvenience that it is expensive to prepare an expensive dedicated steering wheel. In the latter case, there is a disadvantage that a complicated and costly operation is required. On the other hand, this embodiment is extremely advantageous for facilitating work and reducing costs.

In addition, if a plurality of detection protrusions 12 are provided on the shape portion 2D of the steering wheel 2, the steering angle data can be obtained accurately without any complicated work in any vehicle. This is advantageous in conducting an evaluation test using a vehicle.
Further, the resolution and accuracy of the steering angle data obtained by the apparatus and method of the present embodiment depend on the resolution and accuracy of the displacement detected by the displacement detection means 14.
Therefore, steering angle data having the necessary resolution and accuracy can be obtained by appropriately selecting the displacement amount detection means 14.

Further, in the present embodiment, the case where the shape portion 2D is configured by the non-circular shape portion 4 has been described. However, in the present invention, the shape portion 2D is configured by a circular shape portion that is concentric with the rotation axis. Of course, this is applicable.
In this case, as shown in FIG. 12, the waveform S0 indicating the displacement amount d is only the component of the waveform S2 corresponding to the shape of the inclined surface 12A, but the operation of the steering angle detection device 10, in other words, the displacement amount detection. The configurations of the means 14, the data table means 26, the steering angle detection means 30, and the nearest steering angle holding means 32 are the same as those in the above embodiment.

2 ... Steering wheel, 2D ... Shape part, 4 ... Non-circular shape part, 10 ... Steering angle detection device, 14 ... Displacement amount detection means, 26 ... Data table means, 30 ... Steering angle detection means , 32 ...... last steering angle holding means, theta ...... steering angle, theta _{0 ......} last steering angle, d ...... displacement.

Claims (5)

A steering angle detection device for detecting a steering angle of a steering wheel of a vehicle provided with a non-circular shape portion extending around the rotation axis when viewed from the rotation axis direction,
An inclined surface that is arranged along the outer periphery of the shape portion and monotonously increases from the lowest portion along the outer periphery of the shape portion to the highest portion with the highest height, and adjacent to the detection portion A plurality of detection protrusions comprising a standing surface connecting the lowermost part of the protrusion and the uppermost part of the inclined surface and extending along a radial direction of the rotation axis;
A displacement amount detecting means having a displacement amount sensor for detecting a displacement amount in the radial direction of the rotating shaft of the inclined surface that changes with rotation of the steering wheel at a predetermined measurement point;
A data table for creating a data table in which a plurality of steering angles actually measured over one rotation of the steering wheel are associated with displacement amounts detected by the displacement amount detection means corresponding to each of the plurality of steering angles. Creating means;
A data table means for storing the data table,
Steering angle detection means for specifying a steering angle from the data table and outputting steering angle data indicating the steering angle;
Each time a new steering angle is specified by the steering angle detection means, the steering angle holding means updates and holds the steering angle as the nearest steering angle, and
The data table creation means creates an intermediate data table associating a plurality of discretely measured steering angles with displacement amounts detected corresponding to each of the plurality of steering angles. Create a data table with an arbitrary resolution by interpolating the steering angle and displacement amount of
The identification of the steering angle by the steering angle detection means is made based on the displacement amount detected by the displacement amount detection means and the most recent steering angle.
A steering angle detecting device characterized by that. The displacement amount sensor is configured by a non-contact displacement amount sensor fixed to a location in the vehicle compartment facing the plurality of detection protrusions.
The steering angle detection device according to claim 1, wherein: The plurality of detection protrusions are formed along the longitudinal direction of the adhesive tape on the surface opposite to the adhesive surface of the belt-shaped adhesive tape,
Arrangement of the plurality of detection protrusions along the outer periphery of the shape portion is performed by attaching the adhesive surface to the outer periphery of the shape portion.
The steering angle detection device according to claim 1 or 2, wherein A dimension of the standing surface along a radial direction of the rotation axis is in a range of 0.5 to 20 mm;
The steering angle detection device according to any one of claims 1 to 3, wherein A steering angle detection method for detecting a steering angle of a steering wheel of a vehicle provided with a non-circular shape portion extending around the rotation axis when viewed from the rotation axis direction,
An inclined surface that is arranged along the outer periphery of the shape portion and monotonously increases from the lowest portion along the outer periphery of the shape portion to the highest portion with the highest height, and adjacent to the detection portion Providing a plurality of detection protrusions comprising a standing surface connecting the lowermost portion of the protrusion and the uppermost portion of the inclined surface and extending along the radial direction of the rotation axis,
A displacement amount detecting step for detecting a displacement amount in the radial direction of the rotating shaft of the inclined surface that changes with rotation of the steering wheel at a predetermined measurement point;
A data table for creating a data table in which a plurality of steering angles actually measured over one rotation of the steering wheel are associated with displacement amounts detected by the displacement amount detection means corresponding to each of the plurality of steering angles. Creation steps,
A steering angle detection step of identifying a steering angle from the data table and outputting steering angle data indicating the steering angle;
Each time a new steering angle is specified by the steering angle detection means, the steering angle holding step for updating and holding the steering angle as the nearest steering angle,
The identification of the steering angle by the steering angle detection step is made based on the displacement amount detected in the displacement amount detection step and the most recent steering angle.
A steering angle detection method characterized by the above.

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