JPH07113553B2 - Rotation angle detector - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rotation angle detection device for detecting a rotation angle of a steering wheel provided on a vehicle.

[Conventional technology]

Conventionally, a device using a gyro or a geomagnetic sensor has been known as a device for detecting the turning angle of a vehicle. However, the former has a large size and is expensive, and the latter has a problem that the detection system is deteriorated due to the distorted geomagnetism near the building.

Therefore, it is conceivable to detect the rotation angle of the steering wheel and obtain the turning rotation angle of the vehicle from the rotation angle of the steering wheel.
In this case, you don't need expensive equipment like a gyro,
In addition, unlike the geomagnetic sensor, its detection accuracy does not deteriorate under the influence of disturbance such as a building.

[Problems to be Solved by the Invention]

However, when detecting the rotation angle of the handle,
A deviation is likely to occur due to secular change of the detection device. That is, in the above-described detection device, it is difficult to accurately set the neutral rotation angle due to errors and variations in manufacturing and mounting of the device itself, and even if it can be set, an error occurs thereafter due to a change with time. Therefore, there is a problem that the detected rotation angle of the handle includes a deviation.

The present invention has been made in view of the above points, and provides a rotation angle detection device capable of detecting a rotation angle of a steering wheel of a vehicle with high accuracy even when a change with time or the like occurs. The purpose is to do.

[Means for Solving the Problems]

In order to achieve the above object, a rotation angle detection device according to the present invention includes a steering wheel angle detection means for detecting a rotation angle Δφ of a steering wheel provided on a vehicle, a distance detection means for detecting a travel distance ΔL of the vehicle, and a vehicle. A speed detecting means for detecting the traveling speed of the vehicle, the traveling speed belonging to a predetermined speed range, and the traveling distance Δ
Each time L reaches a predetermined distance, the rotation angle Δφ of the steering wheel detected by the steering wheel angle detection means is fetched,
Determining means for determining whether or not the fetched change angle of the rotation angle Δφ of the handle falls within a predetermined angle range; and the plurality of handles determined to belong to the predetermined angle range by the determining means. And a rotation angle of the steering wheel detected by the steering wheel angle detection means with reference to the steering wheel offset angle obtained by the computation means. Rotation angle calculation means for calculating the actual rotation angle of the handle based on Δφ.

[Action]

With the above configuration, the rotation angle Δφ of the steering wheel of the vehicle, the traveling distance ΔL, and the traveling speed are detected. Then, each time the traveling speed belongs to the predetermined speed range and the traveling distance ΔL reaches the predetermined distance, the rotation angle Δφ of the steering wheel detected by the steering wheel angle detecting means is taken in, and the rotation angle Δφ of the taken steering wheel is changed. It is determined whether the angle belongs to a predetermined angle range. This makes it possible to determine whether or not the vehicle is stably maintained in the straight traveling state.

Then, the handle offset angle is obtained by arithmetic operation based on the rotation angles Δφ of the plurality of handles determined to belong to the predetermined angle range by the determining means.
As described above, the handlebar offset angle is obtained based on the plurality of handlebar rotation angles Δφ, so that the accuracy can be improved.

The actual rotation angle of the handle is calculated based on this offset angle, so even if it changes over time,
The effect can be eliminated.

(Example) Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

In FIG. 2, 1 is a steering wheel angle detecting device as steering wheel angle detecting means, 2 is a distance detecting means distance calculating circuit,
3 is a computer. Reference numeral 4 is a proportional constant calculation command switch described later.

As the steering wheel angle detecting device 1, for example, Japanese Patent Laid-Open No.
The shaft rotation direction detecting device disclosed in Japanese Patent No. 148262 can be used. This is because the first disk 11 having two kinds of electrodes formed at equal intervals on the outer periphery is provided on the stationary side, and the shaft is provided with two kinds of electrodes formed at equal intervals so as to face the disk 11. Two discs 12 are provided, and pulse signals of opposite phases are applied to the electrodes of the first disc 11 so that pulse signals appearing on the electrodes of the second disc 12 as the shaft rotates. The rotation direction and rotation angle of the shaft are known from the phase advance / retard and the number of pulses. In this embodiment, 60 pulses are output for each forward and reverse rotation of the steering wheel, and the counter 13 adds or subtracts these pulses to generate steering wheel rotation angle data T.

The distance calculation circuit 2 includes a rotation sensor 21 which detects the rotation of the vehicle speed cable and outputs a pulse signal of 30 pulses per rotation of the cable, and a counter 22 which counts the pulses generated by the rotation sensor 21 and outputs distance data S. Have.

The computer 3 is a microcomputer that executes digital arithmetic processing by software according to a predetermined program, and includes a CPU, ROM, RAM, I / 0 circuit unit, clock generation unit, etc., and a stabilized power supply circuit (not shown in FIG. A stabilized voltage of 5 V is supplied via a not-shown) to enter an operating state, and arithmetic processing is executed in FIGS. 3 to 5 described later. It should be noted that the RAM is constantly supplied with power from the vehicle-mounted battery so that the stored contents are not erased even when the vehicle is not operating (when the key switch is off).

The operation of the above configuration will be described with reference to the program flow charts shown in FIGS. In the vehicle including the respective constituent elements 1 to 4 shown in FIG. 2, when the key switch is turned on at the time of starting the operation, electric power is supplied from the on-vehicle battery to activate the electric systems of the respective parts. Then, the microcomputer 3 is supplied with a stabilizing voltage of 5V from the vehicle-mounted battery via the stabilizing power supply circuit, and becomes in an operating state, and executes the calculation of the main routine shown in FIG.
First, in step 100, registers in the microcomputer 3 and timers are initialized, and variables n and ml are initialized to zero. Next, at step 101, if the proportional constant calculation command switch 4 (FIG. 2) is closed, a proportional constant calculation routine 200 described later is executed. When the switch 4 is open, step 104 and subsequent steps are repeated every 0.1 second unit time (steps 102 and 103).
In steps 104 to 106, the traveling distance ΔL within the unit time is calculated, and in steps 107 to 109, the average steering wheel rotation angle Δφ within the unit time is calculated. That is, the distance data S is read from the counter 22 (step 104), and the counter 22 is reset after reading (step 105). The distance data S is multiplied by the proportional constant K1 to obtain the traveling distance ΔL (step 106). The constant of proportionality K1 is about 1000m when the vehicle speed cable is
In this embodiment, which rotates 637, Is.

Then, the handle rotation angle data T is read from the counter 13 (step 107). At step 108, the average rotation angle data T _A of the rotation angle data T read this time and the rotation angle data T1 read last time is calculated, and the rotation angle data T is calculated.
Is stored as rotation angle data T1. The average steering wheel rotation angle Δ is calculated by multiplying the above average rotation angle data T _A by a proportional constant K2.
Obtain φ (step 109). The proportional constant K2 is Is.

The offset calculation routine in step 300 calculates and updates the offset (deviation) ΔφC of the steering wheel angle.
(Details will be described later.) Subsequently, offset ΔφC is subtracted from the average steering wheel angle Δφ to perform offset compensation (step 110). At step 111, the vehicle rotation angle Δθ within the unit time is calculated by the following formula from the traveling distance ΔL within the unit time and the average steering wheel angle Δφ, and is output (step 112), and the process returns to step 101 to perform the above-mentioned processing. repeat.

Δθ = K · tan Δφ · ΔL The proportional constant K is the proportional constant calculation routine 20 shown in FIG.
Determined by 0. This processing routine will be described below. First, the steering wheel is operated so that the vehicle travels straight ahead and the command switch 4 is closed (step 101).
Is started and the steering wheel rotation angle data TC at this time is read (step 201), then the command switch 4 is once opened, and the process proceeds to step 203, where the steering wheel is rotated to start the vehicle at an appropriate turning radius, and the operation is started. Put on the line. When the command switch 4 is closed, the steering wheel rotation angle data T ₀ at this time is read (step 204), and then the distance counter 22 (FIG. 2) is reset (step 20).
Five). In this state, the vehicle is driven and returns to the start line again. When the command switch 4 is opened, the traveling distance data S ₀ is read from the counter 22 in steps 206 and 204 (step 207) and reset (step 208). Subsequently, the traveling distance L ₀ is calculated from the distance data S ₀ (step 209), and the steering wheel rotation angle data T
A steering wheel rotation angle offset ΔφC and a steering wheel rotation angle φ ₀ are calculated from C and T ₀ (step 210). And step 2
At 11, calculate the proportionality constant and the following equation.

After that, the timer for determining the unit time is reset (step 212), the proportional constant calculation routine ends, and the process returns to step 102 of the main routine.

The proportional constant K can be calculated by K = 1 / tan (π · Nk) · Rk, where Rk is the minimum turning radius of the vehicle and Nk is the maximum turning speed of the steering wheel (from the normal rotation end to the reverse rotation end). It is difficult to measure the above Rk and Nk with high accuracy, and the method of the above embodiment is more accurate.

Next, the offset calculation routine 300 will be described (see FIG. 5). Accumulate the traveling distance ΔL within the unit time (step 301), and proceed to step 303 and onward every time the distance exceeds 10 m, and 1
When it is less than 0 m, the routine proceeds to step 321, the routine 300 is terminated, and the routine returns to the main routine. The processing from step 303 onward will be executed every about 10 m of cumulative traveling distance. In step 303, the total traveled distance is set to zero and the vehicle speed SP (Km / h)
= 36 × ΔL is calculated (step 304). Next step 3
When the vehicle speed SP is in the range of K3 (39 Km / h) and K4 (60 Km / h) at 05, proceed to step 306, and when n = 0, proceed to step 309.
If n ≠ 0, the process proceeds to step 307. In step 307,
The steering wheel rotation angle Δφ obtained in step 109 described above is Δ
It is determined whether or not it is within the range of φA ± K5 (0.05π in this embodiment). If YES, the process proceeds to step 309, and if NO, the n is set to zero in step 308 and the process proceeds to step 321 and returns to the main routine. In step 309, it is stored in Δφn, the average ΔφA of Δφn so far is obtained, and in step 310, 1 is added to n. In step 311, it is determined whether or not n is 10, and if NO, the process proceeds to step 321, returning to the main routine, and if YES, the process proceeds to step 312. If the vehicle speed is in the range of K3 to K4 and the steering wheel rotation angle Δφ for each of 10 consecutive 10 revolutions does not fluctuate so much, the processing of steps 301 to 311 is performed.
This is to find the average value ΔφA of the times.

The processing of steps 313 to 319 is to obtain the three-time average value ΔφB of ΔφA when the continuous three times ΔφA does not change much, following the same procedure as steps 306 to 312. Here, the average value K6 of the variation of ΔφA is 0.05 in this embodiment.
π (step 314).

Handle rotation angle Δ due to the processing from steps 301 to 319
Since the variation in φ is removed and the offset ΔφB in the straight traveling state is obtained, in step 320, ΔφC = ΔφB + Δφ
A new offset ΔφC is obtained by the calculation of C, and the offset calculation routine ends.

Here, the calculation formula Δ of the vehicle rotation angle Δφ in step 111
θ = K · tan Δφ · ΔL will be described. When a normal vehicle turns, its turning center is on an extension of the rear axle, as shown in FIG. If the steering wheel rotation angle Δφ, the turning radius R, and the wheel base 1 are satisfied, the relationship of tan Δφ = 1 / R can be obtained. On the other hand, since there is a relationship of ΔL = R · Δθ between the arc ΔL, the radius R, and the rotation angle Δφ, the following formula can be obtained by substituting the above formula and rearranging.

Δθ = (1 / l) · ΔL · tan Δφ Here, if K = 1 / l, Δθ = K · tan Δφ · ΔL can be obtained.

When Δφ <1, since Δφ≈tan Δφ can be approximated,
It can be expressed as Δθ ≒ K · Δφ · ΔL, but the accuracy is reduced.

Vehicle rotation angle Δθ per unit time calculated by the above procedure
Can be known as a vehicle rotation angle, that is, a vehicle traveling direction from a predetermined reference direction (for example, north direction) by accumulating the values, and can be applied to an azimuth meter and a current position display device.

The vehicle rotation angle Δθ for each unit time is an angular velocity, and the angular velocity or centripetal acceleration calculated from the angular velocity can be used as vehicle running control information.

In the above embodiment, the vehicle rotation angle is calculated for each unit time, but it may be calculated for each unit travel distance.

Further, in the calculation of the proportional constant K, it is not always necessary for the vehicle to make one rotation, and the known rotation angle θ ₀
Just rotate it up to.

Further, although the average value of 10 and 3 times is used in the calculation of the offset ΔφC, any number of times may be used.

Further, the rotation angle θ of the vehicle can be obtained by the following method without being limited to the above formula.

That is, since the angle ε of the direction in which the vehicle is going to travel is determined by the substantial steering wheel angle φ _{0 with} respect to straight travel, the traveling angle ε of the vehicle with respect to a certain steering wheel angle φ ₀ is obtained by measurement, and φ ₀ A map of ε and ε is created, and this map is stored in the ROM of the microcomputer 3.

If the handlebar offset angle is φC and the handlebar angle is φ, the actual handlebar angle φ ₀ is φ
_{Since 0} = φ−φC, the traveling angle ε of the vehicle corresponding to the value of φ ₀ is taken out from the map, and this ε is multiplied by the traveling distance L to obtain the rotation angle θ of the vehicle.

(Effects of the Invention) As described above, the present invention has a plurality of handle rotation angles Δ.
Since the offset angle is obtained based on φ, it is possible to obtain a highly accurate offset angle, and even if a change with time occurs, the actual rotation angle of the steering wheel calculated based on the offset angle can be calculated. It is possible to improve accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of the present invention, FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 3, FIG.
FIG. 5 and FIG. 5 are control flowcharts of the microcomputer shown in FIG. 2, and FIG. 6 is an explanatory diagram of vehicle rotation angle detection by the device of the present invention. 1 …… Handle angle detection device, 2 …… Distance calculation circuit, 3 ……
Computer.

Front page continuation (72) Inventor Akira Kuno 1-1, Showa-cho, Kariya city, Aichi Prefecture, Nihon Denso Co., Ltd. (56) Reference JP-A-60-183518 (JP, A) JP-A-57-41267 ( JP, A) JP 59-186775 (JP, A)

Claims (1)

[Claims] 1. A steering wheel angle detecting means for detecting a rotation angle Δφ of a steering wheel provided on a vehicle, a distance detecting means for detecting a traveling distance ΔL of the vehicle, a speed detecting means for detecting a traveling speed of the vehicle, The traveling speed belongs to a predetermined speed range and the traveling distance Δ
Each time L reaches a predetermined distance, the rotation angle Δφ of the steering wheel detected by the steering wheel angle detection means is fetched,
Determining means for determining whether or not the fetched change angle of the rotation angle Δφ of the handle falls within a predetermined angle range; and the plurality of handles determined to belong to the predetermined angle range by the determining means. And a rotation angle of the steering wheel detected by the steering wheel angle detection means with reference to the steering wheel offset angle obtained by the computation means. A rotation angle detecting device for calculating an actual rotation angle of the handle based on Δφ.