U.S. patent application number 09/947156 was filed with the patent office on 2002-03-07 for apparatus and method for detecting rotation angular speed and automobile using the apparatus.
This patent application is currently assigned to Alps Electric Co., Ltd.. Invention is credited to Hoshi, Toshiyuki, Kato, Hironori, Sanpei, Yoshio.
Application Number | 20020029126 09/947156 |
Document ID | / |
Family ID | 18759469 |
Filed Date | 2002-03-07 |
United States Patent
Application |
20020029126 |
Kind Code |
A1 |
Sanpei, Yoshio ; et
al. |
March 7, 2002 |
Apparatus and method for detecting rotation angular speed and
automobile using the apparatus
Abstract
There is provided a rotation angular speed detection apparatus
capable of detecting a rotation angular speed to reduce an error
when the rotation angular speed for rotating a rotating body is
low. A rotation angular speed detection apparatus comprises: a
receiving part for receiving a rotation angle at predetermined time
intervals from a rotation angle sensor for detecting a rotation
angle of a rotating body; a storage part for storing the received
rotation angle; and a control part for detecting a rotation angular
speed from the rotation angles stored in the storage part; wherein
when a difference between a first arbitrary angle stored and a
second angle stored before the first angle is less than a
predetermined value, the control part determines, from the rotation
angles stored in the storage part, a third angle in which a
difference between the first angle and the third angle is more than
the predetermined value, and wherein the control part divides the
difference between the first angle and the third angle by the time
required from storing of the third angle to storing of the first
angle so as to detect a rotation angular speed.
Inventors: |
Sanpei, Yoshio; (Miyagi-ken,
JP) ; Kato, Hironori; (Miyagi-ken, JP) ;
Hoshi, Toshiyuki; (Rochester, MI) |
Correspondence
Address: |
BRINKS HOFER GILSON & LIONE
P.O. BOX 10395
CHICAGO
IL
60610
US
|
Assignee: |
Alps Electric Co., Ltd.
|
Family ID: |
18759469 |
Appl. No.: |
09/947156 |
Filed: |
September 5, 2001 |
Current U.S.
Class: |
702/145 |
Current CPC
Class: |
G01D 3/08 20130101; B60G
2400/052 20130101; B60G 2400/208 20130101; B60G 17/01933 20130101;
B60T 7/12 20130101; B60G 17/0195 20130101; B62D 15/021 20130101;
B60T 8/171 20130101 |
Class at
Publication: |
702/145 |
International
Class: |
G01P 003/00; G06F
015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 5, 2000 |
JP |
2000-273552 |
Claims
What is claimed is:
1. A rotation angular speed detection apparatus comprising: a
receiving part for receiving an angular single at predetermined
time intervals from a rotation angle sensor for detecting a
rotation angle of a rotating body with respect to the reference
angle; a storage part for storing the rotation angle based on the
received angular signal; and a control part for dividing a
difference between a first arbitrary angle of the rotation angles
stored in the storage part and a second angle stored before the
first angle by the time required from storing of the second angle
to storing of the first angle so as to detect a rotation angular
speed; wherein when the difference between the first angle and the
second angle is less than a predetermined value, the control part
determines, from the angles stored in the storage part, a third
angle stored before the second angle in which a difference between
the first angle and the third angle is more than the predetermined
value, and wherein the control part divides the difference between
the first angle and the third angle by the time required from
storing of the third angle to storing of the first angle so as to
detect a rotation angular speed.
2. The rotation angular speed detection apparatus according to
claim 1, wherein when an angle in which a difference between the
first angle and the angle is more than the predetermined value is
not present in the rotation angles stored in the storage part, the
control part selects an arbitrary rotation angle of the second
angle of the rotation angles stored in the storage part as a fourth
angle, and wherein the control part divides a difference between
the first angle and the fourth angle by the time required from
storing of the fourth angle to storing of the first angle so as to
detect a rotation angular speed.
3. The rotation angular speed detection apparatus according to
claim 2, wherein when a sign of the difference between the first
angle and the second angle is reversed from a sign of the
difference between the second angle and the rotation angle stored
immediately before the second angle, the control part erases the
rotation angle before the second angle of the rotation angles
stored in the storage part.
4. A rotation angular speed detection method comprising the steps
of: detecting a rotation angle of a rotating body at predetermined
time intervals; storing the detected rotation angle; determining a
difference between a first arbitrary angle of the stored rotation
angles and a second angle stored before the first angle; and
detecting a rotation angle speed by dividing the difference by the
time required from storing of the second angle to storing of the
first angle so as to detect a rotation angular speed; wherein when
the difference is less than a predetermined value, a third angle
stored before the second angle in which a difference between the
first angle and the third angle is more than the predetermined
value, is determined from the stored rotation angles, and wherein
the difference between the first angle and the third angle is
divided by the time required from storing of the third angle to
storing of the first angle so as to detect a rotation angular
speed.
5. The rotation angular speed detection method according to claim
4, wherein the control part, when a rotation angle in which a
difference between the first angle and the angle is more than the
predetermined value is not present in the stored rotation angles,
an arbitrary rotation angle of the second angle of the stored
rotation angles is selected as a fourth angle; wherein a difference
between the first angle and the fourth angle is divided by the time
required from storing of the fourth angle to storing of the first
angle so as to detect a rotation angular speed.
6. The rotation angular speed detection method according to claim
5, wherein when a sign of the difference between the first angle
and the second angle is reversed from a sign of the difference
between the second angle and the rotation angle stored immediately
before the second angle, the angle before the second angle of the
stored rotation angles is erased.
7. An automobile comprising: the rotation angular speed detection
apparatus according to claim 1; and a vehicle stability control
system for stabilizing a vehicle; wherein the rotation angular
speed detection apparatus receives an angular signal from an angle
sensor detecting a rotation angle of a steering wheel so as to
detect a rotation angular speed of the steering wheel, and wherein
a rotation angular speed signal based on the detected rotation
angular speed is sent to the vehicle stability control system.
8. The rotation angular speed detection apparatus according to
claim 7, wherein when an angle in which a difference between the
first angle and the angle is more than the predetermined value is
not present in the rotation angles stored in the storage part, the
control part in the rotation angular speed detection apparatus
selects an arbitrary rotation angle of the second angle of the
rotation angles stored in the storage part as a fourth angle, and
wherein the control part divides a difference between the first
angle and the fourth angle by the time required from storing of the
fourth angle to storing of the first angle so as to detect a
rotation angular speed.
9. The rotation angular speed detection apparatus according to
claim 8, wherein when a sign of the difference between the first
angle and the second angle is reversed from a sign of the
difference between the second angle and the rotation angle stored
immediately before the second angle, the control part erases the
rotation angle before the second angle of the rotation angles
stored in the storage part.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an apparatus and method for
detecting a rotation angular speed and to an automobile using the
apparatus. In particular, the present invention relates to an
apparatus and method for detecting a rotation angular speed to
reduce a measurement error when a rotation angular speed is low,
and to an automobile using a rotation angular speed of a steering
wheel detected by the apparatus to stabilize a vehicle.
[0003] 2. Description of the Prior Art
[0004] In recent years, an automobile has been performing total
vehicle stability control such as braking control, suspension
control and traction control for stabilizing a vehicle so that the
driver can drive the automobile safely and comfortably. The total
vehicle stability control detects the rotation angle of a steering
wheel by a rotation angle sensor, detects a rotation angular speed
(a rotating speed) of the steering wheel by a rotation angular
speed detection apparatus from a traveling amount of the detected
rotation angle per predetermined time, and predicts the traveling
direction intended by the driver (the direction to finish turning
the steering wheel) by the detected rotation angular speed so as to
perform the vehicle stability control based on the prediction.
[0005] A prior art rotation angular speed detection apparatus has a
receiving part for receiving an angular signal from a rotation
angle sensor outputting an angular signal corresponding to the
rotation angle of a rotating body, for example, at intervals of 400
microseconds, a storage part for storing a first angle based on the
received angular signal, a sending part for sending the first angle
at intervals of 10 milliseconds, and a control part for determining
a difference between the first angle stored immediately before
sending the same and a second angle stored immediately before
sending the first angle which is then multiplied by 100 (1
second/10 milliseconds) so as to detect a rotation angular speed
(degrees/sec) When the rotation angular speed detection apparatus
is used in an automobile, an angular signal from an angle sensor
outputting an angular signal corresponding to the rotation angle of
a steering wheel is detected described above. Then, a rotation
angular speed signal based on the detected rotation angular speed
is calculated, for example, at intervals of 10 milliseconds to send
the result to vehicle stability control to stabilize the
vehicle.
[0006] Between the rotation angle actually rotating the rotating
body and the rotation angle stored in the storage part, there are
caused a measurement error of the rotation angle due to the
accuracy of the rotation angle sensor, an error at reception due to
electric delay, and an error at conversion of an analog signal to a
digital signal. It is difficult to remove these errors. For
example, when the total of these errors is a maximum of
0.2.degree., a rotation angular speed is calculated by the
abovementioned calculation, an error of 20 (degrees/sec) may be
caused. This error has an error rate of 2% when the rotating body
is rotated largely and for example, a difference of the rotation
angles at intervals of 10 ms is 10.degree. (1000 degrees/sec),
which is not very important. This error has an error rate of 20%
when the rotation amount of the rotating body is relatively small
and for example, a difference of the rotation angles at intervals
of 10 ms is 1.degree. (100 degrees/sec). In this manner, when the
rotation angular speed for actually rotating the rotating body is
low, the error rate of the detected rotation angular speed is very
high.
[0007] When the rotation angular speed detection apparatus is used
in an automobile, the rotation angular speed of the steering wheel
detected by the rotation angular speed detection apparatus is sent
to the vehicle stability control system of the automobile. For
example, when the steering wheel is turned at a small angle when
driving the automobile at high speed on an expressway, the error of
the rotation angular speed sent to the vehicle stability control
system is increased. The vehicle stability control misjudges that
the steering wheel is turned abruptly and performs unnecessary
traction control, so that the vehicle is unstable.
SUMMARY OF THE INVENTION
[0008] The present invention solves the problem above and
accordingly, an object of the present invention is to provide an
apparatus and method capable of detecting a rotation angular speed
to reduce an error when the rotation angular speed for rotating a
rotating body is low, and an automobile which can be driven more
safely when a steering wheel is turned slowly.
[0009] To solve the foregoing problems, in the present invention, a
rotation angular speed detection apparatus comprises: a receiving
part for receiving an angular single at predetermined time
intervals from a rotation angle sensor for detecting a rotation
angle of a rotating body with respect to the reference angle; a
storage part for storing the rotation angle based on the received
angular signal; and a control part for dividing a difference
between a first arbitrary angle of the rotation angles stored in
the storage part and a second angle stored before the first angle
by the time required from storing of the second angle to storing of
the first angle so as to detect a rotation angular speed; wherein
when the difference between the first angle and the second angle is
less than a predetermined value, the control part determines, from
the angles stored in the storage part, a third angle stored before
the second angle in which a difference between the first angle and
the third angle is more than the predetermined value, and wherein
the control part divides the difference between the first angle and
the third angle by the time required from storing of the third
angle to storing of the first angle so as to detect a rotation
angular speed.
[0010] Such a construction can divide the difference between the
rotation angles so as to reduce an error and detect a rotation
angular speed having high accuracy.
[0011] In the present invention, when an angle in which a
difference between the first angle and the angle is more than the
predetermined value is not present in the rotation angles stored in
the storage part, the control part selects an arbitrary rotation
angle of the second angle of the rotation angles stored in the
storage part as a fourth angle, and divides a difference between
the first angle and the fourth angle by the time required from
storing of the fourth angle to storing of the first angle so as to
detect a rotation angular speed.
[0012] Such a construction can detect a rotation angular speed
having high accuracy when the rotating body is hardly rotated. In
addition, the control part selects the rotation angle stored at the
first of the rotation angles stored in the storage part as the
fourth angle, and divides a difference between the first angle and
the fourth angle by the time required from storing of the fourth
angle to storing of the first angle so as to detect a rotation
angular speed. A rotation angular speed having higher accuracy can
be detected.
[0013] In the present invention, when a sign of the difference
between the first angle and the second angle is reversed from a
sign of the difference between the second angle and the rotation
angle stored immediately before the second angle, the control part
erases the rotation angles before the second angle of the rotation
angles stored in the storage part.
[0014] Such a construction can detect a rotation angular speed
having high accuracy when the forward/rearward rotation of the
rotating body is repeated frequently in a short time.
[0015] An automobile of the present invention comprises: the
rotation angular speed detection apparatus; and a vehicle stability
control system for stabilizing a vehicle; wherein the rotation
angular speed detection apparatus receives an angular signal from
an angle sensor detecting a rotation angle of a steering wheel so
as to detect a rotation angular speed of the steering wheel, and
wherein a rotation angular speed signal based on the detected
rotation angular speed is sent to the vehicle stability control
system.
[0016] Such a construction can provide an automobile which can
predict the traveling direction intended by the driver more
precisely and permits suitable vehicle stability control.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a diagram showing the construction of a rotation
angular speed detection apparatus of the present invention;
[0018] FIG. 2 is a flowchart showing a rotation angular speed
detection method of the present invention;
[0019] FIG. 3 is a diagram showing the construction of an
automobile of the present invention; and
[0020] FIG. 4 is a diagram showing an embodiment of the automobile
of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] The apparatus and method for detecting a rotation angular
speed according to the present invention will be described
hereinbelow with reference to FIGS. 1 to 2.
[0022] FIG. 1 is a diagram showing the construction of a rotation
angular speed detection apparatus of the present invention.
[0023] As shown in FIG. 1, a rotation angular speed detection
apparatus 11 of the present invention has a receiving part 12, a
storage part 13, a control part 14, and a sending part 15.
[0024] The receiving part 12 receives at predetermined time
intervals an angular signal from an angle sensor 17 for detecting a
rotation angle of a rotating body 16 such as a steering wheel with
respect to the reference angle.
[0025] The storage part 13 stores at predetermined time intervals
an angle based on the angular signal received by the receiving part
12.
[0026] The control part 14 divides a difference between the first
angle the rotation angles stored in the storage part 13 and the
second angle stored before the first angle by the time required
from storing of the second angle to storing of the first angle so
as to detect a rotation angular speed.
[0027] The sending part 15 sends the rotation angular speed
detected by the control part 14 to a vehicle stability control
system 18.
[0028] In the rotation angular speed detection apparatus 11 thus
constructed, the receiving part 12 receives the angular signal from
the angle sensor 17, the storage part 13 stores an angle based on
the received angular signal, the control part 14 detects a rotation
angular speed is detected from the stored angle, and the sending
part 15 sends a rotation angular speed signal based on the detected
rotation angular speed to the vehicle stability control system 18.
The vehicle stability control system 18 performs various controls
using the sent rotation angular speed signal.
[0029] FIG. 2 is a flowchart of assistance in explaining a method
for detecting a rotation angular speed by the control part 14 of
the rotation angular speed detection apparatus 11 of the present
invention.
[0030] As shown in FIG. 2, the receiving part 12 receives the
angular signal from the angle sensor 16 at intervals of
predetermined time ts (e.g., ts=10 ms) (S21). Then, the storage
part 13 stores an angle .theta.(n) based on the angular signal
received together with a counter n indicating the order of the
angle to be stored (S22). The loop counter .alpha. is set to 1
(S23) which is then compared with the value of the counter n
(S24).
[0031] In step S24, when the counter n is 0 (only the first time
after the main power supply is turned on), a rotation angular speed
cannot be obtained. The rotation angular speed is undefined (S25),
and then, the counter n is counted up (S26) to end the routine
(S27). When the counter n is 1, the equation of the rotation
angular speed .omega.=(.theta.(1)-.theta.(0))/ts is calculated to
detect a rotation angular speed (S28), and then, the counter n is
counted up (S26) to end the routine (S27). When the counter n is 2
or more, a sign of a difference .theta.(n)-.theta.(n-1) between a
first angle .theta.(n) latest-stored and a second angle
.theta.(n-1) stored ts before the first angle .theta.(n) is
compared with a sign of a difference .theta.(n-1)-.theta.(n-2)
between the second angle .theta.(n-1) and an angle .theta.(n-2)
stored ts before the second angle .theta.(n-1) (S29).
[0032] In step S29, when the sign of the difference
.theta.(n)-.theta.(n-1) between the first angle and the second
angle is different from the sign of the difference
.theta.(n-1)-.theta.(n-2) between the second angle and the angle
stored ts before the second angle (Y), the second angle
.theta.(n-1) is .theta.(0), the first angle .theta.(n) is
.theta.(1), the counter n is 1 (S30). The equation of the rotation
angular speed .omega.=(.theta.(1)-.theta.(0))/ts is calculated to
detect a rotation angular speed (S28), and then, the counter n is
counted up (S26) to end the routine (S27). When the sign of the
difference .theta.(n)-.theta.(n-1) between the first angle and the
second angle is equal to the sign of the difference
.theta.(n-1)-.theta.(n-2) between the second angle and the angle
stored ts before the second angle (N) the difference
.vertline..theta.(n)-.theta.(n-.alpha.).vertline. between the first
angle .theta.(n) and an angle .theta.(n-.alpha.) stored
ts.multidot..alpha. before the first angle .theta.(n) is compared
with a predetermine value .theta.s (e.g., .theta.s=10.degree.)
(S31).
[0033] In step S31, the difference
.vertline..theta.(n)-.theta.(n-.alpha.)- .vertline. between the
first angle and the angle stored ts.multidot..alpha. before the
first angle is more than the predetermined value .theta.s (N), for
example, .theta.(n-.alpha.) is a third angle. The equation for
dividing the difference .theta.(n)-.theta.(n-.alpha.) between the
first angle and the third angle by the time ts.multidot..alpha.
required from storing of the third angle to storing of the first
angle, that is, the rotation angular speed
.omega.=(.theta.(n)-.theta.(n-.alpha.))/(ts.multidot..alpha.) is
calculated to detect a rotation angular speed (S28), and then, the
counter n is counted up (S26) to end the routine (S27) The
difference .vertline..theta.(n)-.theta.(n-.alpha.) between the
first angle and the angle stored ts.multidot..alpha. before the
first angle is less than the predetermined value .theta.s (Y), the
counter .alpha. is compared with the counter n (S32).
[0034] In step S32, the counter .alpha. is equal to the counter n
(Y), an angle in which a difference between the first angle
.theta.(n) and the angle is more than the predetermined value
.theta.s is not present in the stored angles. The oldest angle
.theta.(0) of the stored angles is a fourth angle. The equation of
the rotation angular speed
.omega.=(.theta.(n)-.theta.(0))/(ts.multidot..alpha.) is calculated
to detect a rotation angular speed (S28) and then, the counter n is
counted up (S26) to end the routine (S27). When the counter .alpha.
and the counter n are not equal (N), the counter .alpha. is counted
up (S33) to return the routine to step S31. The routine is
repeated.
[0035] In the operation described above, a difference between the
first angle of the stored angles and another one angle selected is
divided by a difference in time storing two angles to detect a
rotation angular speed.
[0036] In the present invention, when the difference between the
first angle .theta.(n) and the second angle .theta.(n-1) is less
than the predetermined value .theta.s, the third angle
.theta.(n-.alpha.) in which the difference between the first angle
.theta.(n) and the third angle .theta.(n-a) is more than the
predetermined value .theta.s is determined from the stored angles,
and the difference .theta.(n)-.theta.(n-.alpha.) between the first
angle and the third angle is divided by the time
ts.multidot..alpha. required from storing of the third angel to
storing of the first angle so as to detect the rotation angular
speed. The rotation angular speed can be detected using a
sufficiently large angle .theta.s (e.g., 10.degree. or more) as
compared with an error (the total of a measurement error of the
rotation angle due to the accuracy of the angle sensor, an error at
reception due to electric delay, and an error at converting an
analog signal to a digital signal, e.g., 0.2.degree.). The rotation
angular speed having high accuracy (e.g., an error rate of below
2%) can be detected.
[0037] The step S32 is a process when the angle in which the
difference between the first angle .theta.(n) and the angle is more
than the predetermined value .theta.s is not present in the stored
angles. In the step, when the angle in which the difference between
the first angle .theta.(n) and the angle is more than the
predetermined value .theta.s is not present, the oldest angle
.theta.(0) of the stored angles is a fourth angle, for example. The
equation of the rotation angular speed
.omega.=(.theta.(n)-.theta.(0))/(ts.multidot..alpha.) is calculated
to detect the rotation angular speed. When the rotating body 16 is
hardly rotated, the difference is divided by the longest time
interval (ts.multidot..alpha.) for storing the stored angles. The
error rate is low (the difference is divided by ts in the prior
art, so that the error rate is 1/.alpha. as compared with the prior
art) so as to detect the rotation angular speed having high
accuracy. The arbitrary angle of the angles stored before the first
angle .theta.(n) is selected from the angles stored in the storage
part 13 as the fourth angle. The error rate can be reduced as
compared with the prior art rotation angular speed apparatus so as
to naturally detect the rotation angular speed having high
accuracy.
[0038] The steps S29 and S30 are processes when the rotation
direction of the rotating body 16 is reversed. The two steps erase
the angles before the rotation direction of the rotating body 16 is
reversed. When determining an angle in which the difference between
the first angle .theta.(n) and the angle is more than the
predetermined value .theta.s, the routine does not go back to the
angle before the rotation direction is reversed. When the rotating
body 16 frequently repeats forward/rearward rotation within a short
time, soon after the forward/rearward direction of the rotating
body 16 is switched, the forward/rearward rotation direction of the
rotation angular speed of the rotating body 16 can be detected
correctly.
[0039] FIG. 3 is a diagram showing the construction of an
automobile using the rotation angular speed detection apparatus 11
of the present invention. In FIG. 3, the same constructions as in
FIG. 1 are indicated by similar numerals, and the detailed
description thereof is omitted.
[0040] As shown in FIG. 3, an automobile 31 of the present
invention has the rotation angular speed detection apparatus 11 and
the vehicle stability control system 18 for stabilizing a
vehicle.
[0041] The rotation angular speed detection apparatus 11 receives
an angular signal from the angle sensor 17 for detecting the
rotation angle of the steering wheel 16 as the rotating body with
respect to the reference angle so as to detect a rotation angular
speed of the steering wheel 16, and then, sends a rotation angular
speed signal based on the detected rotation angular speed to the
vehicle stability control system 18.
[0042] The vehicle stability control system 18 is a control system
for safely driving a vehicle including braking control 18a,
suspension control 18b, auto-leveling control 18c, and traction
control 18d. The vehicle stability control system 18 receives a
rotation angular speed signal based on the rotation angular speed
of the steering wheel 16 detected by the rotation angular speed
detection apparatus 11. Then, the vehicle stability control system
18 predicts the traveling direction intended by the driver (the
direction to finish turning the steering wheel) from the rotation
angular speed of the steering wheel 16 based on the received
rotation angular speed signal so as to safely control the
vehicle.
[0043] In addition, the rotation angular speed detection apparatus
11 is connected through a CAN (Controller Area Network) transceiver
32 to a communication BUS 33 to a LAN system in the vehicle as a
multiplex transmission path, so as to be mutually communicated with
the vehicle stability control system 18 also connected to the
communication BUS 33 or with a vehicle speed sensor 49 for
detecting the speed of the vehicle.
[0044] FIG. 4 is a diagram showing an embodiment of the automobile
31 of the present invention. As shown in FIG. 4, for example, a
sending signal from the rotation angular speed detection apparatus
11 is received by the braking control 18a for controlling
front/rear brakes 34. Then, a control signal sent from the braking
control 18a controls the front/rear brakes 34. In addition, the
sending signal from the rotation angular speed detection apparatus
11 is received by the suspension control 18b for controlling
front/rear suspensions 35. A control signal sent from the
suspension control 18b controls the front/rear suspensions 35. The
total vehicle stability control is performed in this manner.
[0045] The automobile 31 uses the rotation angular speed detection
apparatus 11 of the present invention. An error is reduced when the
traveling direction intended by the driver is predicted, so that
the suitable vehicle stability control is possible. The automobile
31 can thus be driven more safely.
[0046] As described above, according to the present invention, a
rotation angular speed detection apparatus comprises: a receiving
part for receiving an angular single at predetermined time
intervals from a rotation angle sensor for detecting a rotation
angle of a rotating body with respect to the reference angle; a
storage part for storing the rotation angle based on the received
angular signal; and a control part for dividing a difference
between a first arbitrary angle of the rotation angles stored in
the storage part and a second angle stored before the first angle
by the time required from storing of the second angle to storing of
the first angle so as to detect a rotation angular speed; wherein
when the difference between the first angle and the second angle is
less than a predetermined value, the control part determines, from
the angles stored in the storage part, a third angle stored before
the second angle in which a difference between the first angle and
the third angle is more than the predetermined value, and wherein
the control part divides the difference between the first angle and
the third angle by the time required from storing of the third
angle to storing of the first angle so as to detect a rotation
angular speed. The present invention can divide the difference
between the rotation angles so as to reduce an error and detect a
rotation angular speed having high accuracy.
[0047] According to the present invention, an automobile comprises:
the rotation angular speed detection apparatus; and a vehicle
stability control system for stabilizing a vehicle; wherein the
rotation angular speed detection apparatus receives an angular
signal from an angle sensor detecting a rotation angle of a
steering wheel so as to detect a rotation angular speed of the
steering wheel, and wherein a rotation angular speed signal based
on the detected rotation angular speed is sent to the vehicle
stability control system. The present invention can provide an
automobile which can predict the traveling direction intended by
the driver more precisely and permits suitable vehicle stability
control.
* * * * *