JPH07113526B2 - Automotive load control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention relates to a device for controlling an automobile load according to a rotating state of a steering wheel, and more particularly to a rotating state of the steering wheel. The present invention relates to a vehicle load control device in which an absolute encoder detects the indicated signal.

(Prior Art) In recent years, in automobiles, in order to obtain better steering stability or comfortable riding comfort, damping force control of suspension according to the rotation angle (steering angle) of the steering wheel and traveling speed, It is considered to perform shift position control of an automatic transmission, steering control of rear wheels (so-called four-wheel steering system control), and the like.

For the above-mentioned control, a rotation detection device for detecting the rotation angle (and the rotation direction as necessary) of the steering wheel is required. As such a rotation detection device, it has been conventionally considered to use an absolute encoder that generates a position signal indicating an absolute amount of rotation of a steering wheel from a specific position (for example, a neutral position). That is, as this type of encoder, for example, an encoder provided with a brush on a rotating member that follows the rotation of a steering wheel and a resistor that generates a resistance value output according to the sliding contact position of the brush is provided. With this model, the brush position is adjusted in advance so that a predetermined resistance value output (output indicating the origin of the absolute encoder) can be obtained with the steering wheel in the neutral position. ing.

(Problems to be Solved by the Invention) Recently, with the maturation of the automobile market, it is required to control the load of the automobile with high accuracy. For this purpose, the absolute encoder as described above is required. When the load of the vehicle is controlled by the output, the output indicating the origin and the neutral position of the steering wheel must be exactly matched. However, when the absolute encoder is mounted, the dimensional error of the parts, the assembly error, and the error due to the variation in the assembly accuracy on the steering wheel side are superimposed, and the actual neutral position of the steering wheel and the absolute encoder are overlapped. There is a possibility that the neutral position indicated by the output of the origin will shift. Therefore, in such a case, the error of the position signal from the absolute encoder becomes large, and the control accuracy of the vehicle load deteriorates.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a position signal from an absolute encoder used for controlling a vehicle load, that is, a position signal indicating a rotation amount of a steering wheel from a specific position. An object of the present invention is to provide a vehicle load control device that can easily and surely eliminate an error, and thus can control a vehicle load with high accuracy.

[Structure of the Invention] (Means for Solving the Problems) An automobile load control apparatus according to the present invention is an absolute encoder that is assembled to generate a position signal indicating the amount of rotation of a steering wheel from a specific position. ,
Setting means for outputting a storage command signal when the steering wheel is in the specific position, and an error correction signal corresponding to the position signal from the absolute encoder at the time the storage command signal is output are stored. The storage means is provided respectively, and the control means for controlling the load on the vehicle is provided based on the signal obtained by correcting the position signal from the absolute encoder by the error correction signal.

(Function) The position signal output from the absolute encoder indicates the amount of rotation of the steering wheel from a specific position. However, in reality, the steering wheel may be affected by dimensional errors of parts, assembly errors, and variations in assembly accuracy. It may deviate from the actual amount of rotation of the wheel. On the other hand, the position signal at the time when the storing command signal is output from the setting means accurately indicates the state where the steering wheel is at the specific position. Therefore, the signal obtained by correcting the position signal output from the absolute encoder according to the rotation of the steering wheel by the stored content of the storage means, that is, the error correction signal corresponding to the position signal at the above-mentioned time point is the actual steering wheel Accurately corresponds to the amount of rotation of the vehicle, and the vehicle load can be controlled with high accuracy based on such a corrected signal.

(Embodiment) A first embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

In FIG. 3, reference numeral 1 is a steering wheel connected to a steering shaft (not shown), and 2 is a plastic annular base fixed to an appropriate stationary portion (for example, a steering column) while surrounding the steering shaft. It is formed in a double cylinder shape having a side wall 2a and an inner peripheral side wall 2b. Reference numeral 3 denotes a cylindrical coupling body, for example made of plastic, rotatably arranged between the periphery of the steering shaft and the inner periphery of the base 2. This has a projection 3a projecting on the upper surface thereof, which is a recess on the steering wheel 1 side. By engaging with the steering wheel 1
It is provided so as to rotate integrally with.

Reference numeral 4 denotes a cylindrical rotor rotatably arranged on the lower surface side of the base 2 so as to surround the connecting body 3, and an engaging groove 4a on the inner peripheral surface of the rotor is provided on the outer peripheral surface of the connecting body 3 so as to project therefrom. The rotor 4 is engaged with the mating protrusion 3b, whereby the rotor 4 is configured to rotate integrally with the connecting body 3 and further with the steering wheel 1. Further, on the outer peripheral surface of the rotor 4, a sun gear 6 which is a part of a gear mechanism 5 including a planetary gear mechanism is provided.

The gear mechanism 5 includes, in addition to the sun gear 6, an internal gear 7 formed on the inner periphery of the outer peripheral side wall 2a of the base 2, and a planetary gear including a two-stage gear interposed between the sun gear 6 and the internal gear 7. Have eight. Further, 9 is a decelerating rotating body which is an object to be driven by the gear mechanism 5, which is composed of an annular plate and is arranged in the outer peripheral side wall 2a of the base 2 so as to rotate around the rotor 4. The planetary gear 8 is rotatably supported on a support shaft 9a that is integrally provided upright on the deceleration rotor 9. Here, the small-diameter pinion 8a located on the upper stage of the planetary gear 8 is meshed with the internal gear 7, and the large-diameter pinion 8b located on the lower stage is meshed with the sun gear 6, thus configured. In the gear mechanism 5, the rotation of the steering wheel 1 is converted into the revolution force of the planetary gears 8, and the revolution force is transmitted to the deceleration rotor 9. The reduction ratio at this time is set to about 1/4. In this case, in a general automobile, the movable range of the steering wheel 1 (so-called lock-to-lock range) is 3.5.
Since the rotation speed is set to about the rotation amount, the rotation range of the deceleration rotation body 9 is suppressed to less than one rotation.

10 is a composite substrate fixed to the lower surface of the base 2,
As shown in FIG. 4, the endless annular electrode patterns 11 and 12 arranged concentrically are formed on the lower surface of this by printing, and the first resistor located inside the electrode pattern 11 is also formed. A first resistance pattern 13 having an end ring as a body and a second resistance pattern 14 having an end ring as a second resistor located outside the electrode pattern 12 are formed by printing, respectively. In Figure 4, each pattern 11-14 is marked with a shaded band). In addition, the composite substrate 10 is provided with terminals 11a and 12a connected to the electrode patterns 11 and 12, respectively, and terminals 13a and 13b and second resistors connected to both ends of the first resistance pattern 13 are provided. Terminals 14a and 14b connected to both ends of the pattern 14 are provided respectively. An insulating coating 15 is applied to the portion shown by the chain double-dashed line in FIG.

The rotor 4 is provided with an arm 4b, and the arm 4b is provided with a first brush 16 bridging between the electrode pattern 11 and the first resistance pattern 13.
Then, the brush 16, the electrode pattern 11, the first resistance pattern 13 and the rotor 4 constitute a first absolute encoder 17. At this time, the first brush
Reference numeral 16 is provided so as to be movable in the circumferential direction of the rotor 4, and in a state where the steering wheel 1 is in a neutral position which is a specific position, an intermediate point of the first resistance pattern 13 (C ₁ point in FIG. 4). It is adjusted so as to bridge between the electrode pattern 11 and the electrode pattern 11.

Therefore, when the steering wheel 1 is in the neutral position, the resistance value between the terminals 11a and 13a and the resistance value between the terminals 11a and 13b are equal, but depending on whether the steering wheel 1 is rotated right or left. Each resistance value changes. Especially, terminals 11a and 13b
In the case of focusing on the resistance value between them, the resistance value increases linearly as the steering wheel 1 is rotated to the right (rotation in the direction of arrow A in FIG. 4) and linearly to the left. Will be reduced. In this case, a constant voltage Vc (the ground potential of the terminal 13b is applied) is applied between the terminals 13a and 13b, so that the steering wheel 1 rotates between the terminals 11a and 13b. A first voltage signal V _{1 that} is a position signal that changes as shown by the solid line in FIG. 5 is output. That is, the first voltage signal V ₁ changes from zero to Vc every time the steering wheel 1 makes one revolution, and the rotation angle and the rotation direction of the steering wheel 1 can be detected.

On the other hand, the deceleration rotor 9 is provided with a second brush 18 bridging the electrode pattern 12 and the second resistance pattern 14, and the brush 18, the electrode pattern 12, and the second resistance pattern 14 are provided. The decelerating and rotating body 9 constitutes a second absolute encoder 19. At this time, the second
The brush 18 is provided so that it can be moved and adjusted in the circumferential direction of the deceleration rotor 9, and when the steering wheel 1 is in the neutral position, the brush 18 has an intermediate point (C ₂ point in FIG. 4) of the second resistance pattern 14. ) And the electrode pattern 12 are bridged.

Therefore, when the steering wheel 1 is in the neutral position, the resistance value between the terminals 12a and 14a and the resistance value between the terminals 12a and 14b are equal, but depending on whether the steering wheel 1 is rotated right or left. Each resistance value changes. In particular, terminals 12a and 14b
When focusing on the resistance value between them, the resistance value increases linearly as the steering wheel 1 is rotated clockwise and decreases linearly as the steering wheel 1 is rotated counterclockwise. In this case as well, a constant voltage Vc (the ground potential of the terminal 14b) is applied between the terminals 14a and 14b, so that the steering wheel 1 is rotated between the terminals 12a and 14b. A second voltage signal V _{2 which} is a changing position signal is output as shown by the chain double-dashed line in FIG. That is, the second voltage signal V ₂ changes from zero to Vc in response to the steering wheel 1 being rotated about 3.5 times, thereby changing the rotation angle and the rotation direction of the steering wheel 1 from the neutral position. It can be detected.

FIG. 6 schematically shows the configuration of the signal processing circuit 20 for synthesizing the first and second voltage signals V ₁ and V ₂ . In FIG. 6, reference numerals 21 and 22 are analog switches that are made conductive only when a high level signal is received at the gate terminal, and one analog switch 21 is provided between the first absolute encoder 17 and the output terminal 23. The other analog switch 22 is interposed between the second absolute encoder 19 and the output terminal 23. twenty four
Is a discriminating circuit for receiving the second voltage signal V ₂ from the second absolute encoder 19, which is within a range of ± 45 ° from the neutral position of the steering wheel 1 indicated by the voltage signal V ₂ . The discriminator signal Sd (high level signal) is output only when Then, the determination signal Sd is the analog switch 21
Of the analog switch 22 and the gate terminal of the analog switch 22 via the inverter 25, and the auxiliary output terminal 26 to an external circuit.

As a result of such a configuration, in the range where the rotation angle of the steering wheel 1 from the neutral position is within ± 45 °, the analog switch 21 conducts and the first voltage signal V ₁ from the first absolute encoder 17 is reached. Is the output terminal 23
Is output through. At this time, the determination signal Sd is output from the auxiliary output terminal 26. Then, the rotation angle of the steering wheel 1 from the neutral position is ± 45.
° In the range beyond the, is output through the second voltage signal V ₁ is output 23 from the second absolute-type encoder 19 an analog switch 22 becomes conductive. That is, as the steering wheel 1 is rotated, the output terminal 23
As shown in FIG. 7 (a), a combined voltage signal Vn, which is a position signal obtained by combining the first and second voltage signals V ₁ and V ₂ , is output from the auxiliary output terminal 26 (b) in FIG. The discrimination signal Sd as shown in () is output. The composite voltage signal Vn from the output terminal 23 is used for controlling the vehicle load (suspension control, automatic transmission control, etc.) as described later, but the determination signal Sd from the auxiliary output terminal 26 is The composite voltage signal Vn during control is
It is used to determine which one of the first and second voltage signals V ₁ and V ₂ corresponds.

Now, FIG. 1 shows an outline of a vehicle load control system using the combined voltage signal Vn and the discrimination signal Sd. In FIG. 1, 27 is an EPROM as a storage means, 28
Is a setting means including a switch element, for example, a wire cut switch, which is configured to output a storage command signal Sa when the signal wire in the wire cut switch is cut by a tool or the like. At this time, the cutting of the signal wire as described above is performed, for example, in the automobile production line when the steering wheel 1 is in the neutral position (straight ahead position). 29
Is a load for automobiles, examples of which include an electromagnetic solenoid for changing the damping force of a suspension or an electromagnetic solenoid for changing the shift position of an automatic transmission. Reference numeral 30 denotes a control circuit as a control means, which is configured by using a microcomputer, and has a combined voltage signal Vn from the signal processing circuit 20, a discrimination signal Sd, the stored contents of the EPROM 27, a storage command signal Sa from the setting means 28, and The vehicle load 29 is controlled based on a control program stored in advance.

Therefore, in the following, of the control program of the control circuit 30, the contents of the portion related to the gist of the present invention will be described with reference to FIG.

That is, when the storage command signal Sa is first input, in other words, when the steering wheel 1 is at the neutral position, the control circuit 30 reads the composite voltage signal Vn input at that time and temporarily. Memorize (steps a and b). Then, ΔV = Vn−Vc / 2 is calculated, and the calculated result ΔV is used as an error correction signal in the EPROM 27.
(Steps c and d).

Here, Vc / 2 corresponds to the neutral position of the steering wheel 1 indicated by the composite voltage signal Vn, as can be understood from FIGS. 5 and 7, and therefore the error correction signal ΔV is It represents the deviation between the actual neutral position of the steering wheel 1 and the neutral position detected by the first and second absolute encoders 17 and 19. That is, the combined voltage signal Vn indicates the amount of rotation of the steering wheel from the neutral position, but actually the first and second
Due to dimensional errors of parts, assembly errors, and variations in assembly accuracy of the absolute encoders 17 and 19 in Fig. 7, there is a case where the characteristic curve originally required is deviated as shown by the broken line in Fig. 7. The voltage value indicated by ΔV appears as an error therein.

The control circuit 30 stores the error correction signal ΔV in the EPROM 27 as described above, and then the combined voltage signal Vn
And a correction signal V′n obtained by subtracting the error correction signal ΔV from the combined voltage signal Vn (step e,
f) The control routine of the vehicle load 29 is executed based on the correction signal V'n. Then, after this, a loop for sequentially executing the steps e and f and the control routine g is formed.

In the configuration of this embodiment described above, the error correction signal ΔV stored in the EPROM 27 is the actual neutral position of the steering wheel 1 and the combined voltage signal sequentially input.
Since this corresponds to the deviation from the neutral position indicated by Vn, that is, the error, this error correction signal Δ
Correction signal V'obtained by subtracting V from the combined voltage signal Vn
The above-mentioned error is eliminated and n corresponds to the actual amount of rotation of the steering wheel 1 accurately. Therefore, the vehicle load 29 due to the control circuit 30
The control accuracy of is extremely high. Further, the second voltage signal V ₂ from the second absolute encoder 19 changes linearly even when the steering wheel 1 is rotated a plurality of times, and thus the second voltage signal V ₂
Based on the above, the rotation angle and the rotation direction of the steering wheel 1 from the neutral position can be detected in a wide range in real time. However, since the second voltage signal V ₂ is obtained by decelerating the rotation of the steering wheel 1, its resolution, that is, accuracy is low. On the other hand, the first voltage signal V output from the first absolute encoder 17
₁ is a rotor 4 that rotates integrally with the steering wheel 1.
However, although the neutral position of the steering wheel 1 cannot be specified, the accuracy of the information about the rotation angle and the rotation direction of the steering wheel 1 obtained based on this is high. Therefore, the first and second voltage signals V ₁ and V ₂ are
The synthesized voltage signal Vn synthesized so as to complement each other by the signal processing circuit 20 shows the rotation angle and the rotation direction of the steering wheel 1 from the neutral position in a wide range with high accuracy and in real time. In this case, in this embodiment, the rotation range of the steering wheel 1 that requires particularly high accuracy (± 45 from the neutral position).
Since the first voltage signal V ₁ is used in the range (° range), the vehicle suspension control, automatic transmission control, etc. can be finely performed.

In the above embodiment, the error correction signal is ΔV (= Vn
-Vc / 2) is stored in the EPROM27, but the combined voltage signal Vn at the time when the storage command signal Sa is output may be stored as it is in the EPROM27 as an error correction signal. In circuit 30, the combined voltage signal
Every time when Vn is read, the calculation of the error based on the above stored contents may be performed. Further, in the above embodiment, the storage means
Although the EPROM 27 is used, other storage means such as a RAM with a backup power supply may be used instead of the EPROM 27.

FIG. 8 shows a second embodiment of the present invention, and only the parts different from the first embodiment will be described below. That is, 31 is a setting means, which has a function of detecting the traveling distance of the automobile, and is configured to output the storage command signal S'a when the traveling distance reaches a constant value. 32 is an average value calculation circuit, which is a composite voltage signal
The average value of Vn is calculated in real time, and the calculation result is output as the average position signal Vna. In the control circuit 30, the average position signal when the storage command signal S'a is given.
It has a function to store Vna in EPROM 27. At this time, the average position signal Vna when the vehicle travels for a certain distance is close to the combined voltage signal Vn when the steering wheel 1 is in the neutral position. It can be used for error correction. Therefore, also in this embodiment, the same effect as that of the first embodiment can be obtained.

In the second embodiment, the function of the average value calculation circuit 32 may be obtained by the control program of the control circuit 30.

Besides, the present invention is not limited to the embodiments described above and shown in the drawings. For example, it is not necessary to provide two types of absolute encoders, and various modifications are made without departing from the scope of the invention. be able to.

EFFECTS OF THE INVENTION According to the present invention, as is apparent from the above description, a position signal indicating the rotational position of the steering wheel is obtained by the absolute encoder, and the load of the vehicle is controlled by the position signal. The device has an excellent effect that the error of the position signal can be eliminated easily and surely, and the load of the vehicle can be controlled with high accuracy.

[Brief description of drawings]

1 to 7 show a first embodiment of the present invention, FIG. 1 is a block diagram showing an outline of an electrical configuration, and FIG. 2 shows a main part of control contents by a control means. FIG. 3 is a flow chart, FIG. 3 is a vertical cross-sectional view of the absolute type encoder and its related parts, FIG. 4 is a front view showing the main part of FIG. 3, FIG. 5 is an output characteristic diagram of the absolute type encoder, and FIG. FIG. 7 is an electrical configuration diagram showing the outline of the signal processing circuit, and FIG. 7 is an output characteristic diagram of the signal processing circuit. Further, FIG. 8 is a view corresponding to FIG. 1 of the second embodiment of the present invention. In the figure, 1 is a steering wheel, 2 is a base, 4 is a rotor, 5 is a gear mechanism, 6 is a sun gear, 7 is an internal gear, 8 is a planetary gear, 9 is a deceleration rotor, 10 is a composite substrate, 1
1, 12 is an electrode pattern, 13 is a first resistance pattern, 14 is a second resistance pattern, 16 is a first brush, 17 is a first absolute encoder, 18 is a second brush, and 19 is a second brush.
Absolute encoder, 20 is a signal processing circuit, 27
Is an EPROM (storage means), 28 is a setting means, 29 is a vehicle load, 30 is a control circuit (control means), 31 is a setting means, and 32 is an average value calculation circuit.

Claims (4)

[Claims] Claim: What is claimed is: 1. An apparatus for controlling an automobile load according to a rotating state of a steering wheel,
An absolute encoder assembled so as to generate a position signal indicating a rotation amount from a specific position according to the rotation of the steering wheel, and setting means for outputting a storage command signal in a state where the steering wheel is at the specific position. And storage means for storing an error correction signal corresponding to the position signal from the absolute encoder at the time when the storage command signal is output, and a position signal from the absolute encoder by the error correction signal. And a control means for controlling the load on the vehicle on the basis of the corrected signal. 2. The vehicle load control device according to claim 1, wherein the specific position corresponding to the absolute encoder is a neutral position of the steering wheel. 3. The vehicle load control device according to claim 1, wherein the setting means includes a switch element that generates a storage command signal in response to a manual operation. . 4. The setting means is configured to generate a storage command signal when the automobile has traveled a certain distance or more, and the storage means is configured to store an average value of the position signals from the absolute encoder. The load control device for an automobile according to claim 1, wherein