U.S. patent application number 09/948237 was filed with the patent office on 2002-03-14 for detecting apparatus of vehicle speed.
Invention is credited to Ohkubo, Masashi.
Application Number | 20020030622 09/948237 |
Document ID | / |
Family ID | 18760382 |
Filed Date | 2002-03-14 |
United States Patent
Application |
20020030622 |
Kind Code |
A1 |
Ohkubo, Masashi |
March 14, 2002 |
Detecting apparatus of vehicle speed
Abstract
A detecting apparatus of vehicle speed including detecting means
for emitting an electromagnetic wave or an ultrasonic wave to a
road surface and detecting traveling speed of a vehicle from the
Doppler effect produced in a reflected wave thereof, a transmitting
circuit for sending information about the traveling speed detected
by the detecting means by radio, a power generation mechanism for
generating power by vibration produced in the vehicle, and a
charging circuit for charging a charging type battery by an output
voltage of the power generation mechanism.
Inventors: |
Ohkubo, Masashi; (Kanagawa,
JP) |
Correspondence
Address: |
Jay H. Maioli
Cooper & Dunham LLP
1185 Avenue of the Americas
New York
NY
10036
US
|
Family ID: |
18760382 |
Appl. No.: |
09/948237 |
Filed: |
September 7, 2001 |
Current U.S.
Class: |
342/104 ;
180/167; 180/169 |
Current CPC
Class: |
G01S 7/003 20130101;
G01S 13/60 20130101; B60T 7/16 20130101; G01S 15/60 20130101 |
Class at
Publication: |
342/104 ;
180/169; 180/167 |
International
Class: |
G01S 013/60; B62D
001/24; B60T 007/16 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 11, 2000 |
JP |
P2000-274652 |
Claims
What is claimed is:
1. A detecting apparatus of vehicle speed comprising: detecting
means for emitting an electromagnetic wave or an ultrasonic wave to
a road surface and detecting traveling speed of a vehicle from the
Doppler effect produced in a reflected wave thereof; a transmitting
circuit for sending information about the traveling speed detected
by the detecting means by radio; a power generation mechanism for
generating power by vibration produced in said vehicle; and a
charging circuit for charging a charging type battery by an output
voltage of the power generation mechanism.
2. The detecting apparatus of vehicle speed according to claim 1,
wherein voltage of said charging type battery is supplied to said
detecting means and said transmitting circuit as operating voltage
thereof.
3. The detecting apparatus of vehicle speed according to claim 2,
further comprising: a switching circuit; and a detecting circuit
for detecting a magnitude of the output voltage of said power
generation mechanism, wherein said switching circuit is connected
in series with the charging type battery and a voltage line between
said detecting means and said transmitting circuit, an output of
said detecting circuit is supplied to said switching circuit as a
control signal thereof, and when the magnitude of the output
voltage of said power generation mechanism is equal to or lower
than a predetermined value, said switching circuit is turned
off.
4. The detecting apparatus of vehicle speed according to claim 3,
wherein a hysteresis characteristic is provided to on/off of said
switching circuit.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a detecting apparatus of
vehicle speed preferably used in a navigation apparatus for vehicle
mounting or the like.
[0003] 2. Description of the Related Art
[0004] A navigation apparatus for vehicle mounting is constituted
as shown by, for example, FIG. 1. That is, in FIG. 1, there is
provided a microcomputer 10 as a control circuit for controlling
operation of a total of the navigation apparatus. The microcomputer
10 includes CPU (Central Processing Unit) 11 for executing various
programs, ROM (Read Only Memory) 12 written with the programs, RAM
(Random Access Memory) 13 for work area and an involatile memory 14
for holding various data and further includes an interface circuit
16 and an LCD (Liquid Crystal Display) controller 17, which are
connected to each other via a system bus 19.
[0005] Further, the interface circuit 16 is connected with various
operation keys (operation switches) 15 and the LCD controller 17 is
connected with a color LCD 18.
[0006] Further, the navigation apparatus of FIG. 1 is a case of
further using DVD (Digital Versatile Disc)--ROM 21 as medium of
large capacity having map data, that is, DVD-ROM 21 is contained
with various map data necessary for navigation. Further, there is
provided a DVD-ROM drive apparatus 22 for reading data from DVD-ROM
21 and the drive apparatus 22 is connected to the system bus
19.
[0007] Further, radio wave from a navigation satellite, for
example, a GPS (Global Positioning System) satellite is received by
a GPS antenna 23 and a received signal thereof is supplied to a GPS
unit (receiving circuit) 24, data of a position of its own is
outputted from the GPS unit 24 and the data is supplied to the
microcomputer 10.
[0008] Further, a self-contained navigation unit, for example, a
gyro 25 is provided, data in a direction of moving the vehicle per
se is outputted from the gyro 25 and the data is supplied to the
microcomputer 10. Further, a vehicle speed sensor for detecting
traveling speed of the vehicle is provided and an output signal
thereof is supplied to the microcomputer 10.
[0009] According to such constitution, output signals from the GPS
unit 24, the gyro 25 and the vehicle speed sensor 26 are processed
by CPU 11 to thereby determine a position of the vehicle of its own
and map data of a map including the position of the vehicle of its
own is read from DVD-ROM 21. Further, LCD 18 displays an electronic
map centering on a vicinity of the position of the vehicle of its
own in accordance with the read map data and displays, for example,
a triangular mark (.DELTA.) indicating the vehicle of its own at
the position of the vehicle of its own.
[0010] Further, in this case, the position of the vehicle of its
own can be determined with considerable accuracy only by the GPS
unit 24; however, radio wave from the GPS satellite may not be
received behind a building or in a tunnel. In such an occasion,
determination of the position of the vehicle of its own becomes
inaccurate or cannot be carried out at all.
[0011] Hence, the navigation apparatus of FIG. 1 is provided with
the gyro 25 and the vehicle speed sensor 26, thereby, even when
radio wave from the GPS satellite cannot be received, the position
of the vehicle of its own can be determined.
[0012] Further, as a method of detecting the traveling speed of the
vehicle by the vehicle speed sensor 26, there are reduced into
practice:
[0013] (1) outputting a speed signal from a signal cable reaching a
speedometer of the vehicle;
[0014] (2) detecting rotational speed of tire, that is, traveling
speed by magnetizing tire by a magnet and detecting the magnetism
by a magnetic sensor.
[0015] However, in the case of the method in item (1), it is
considerably difficult for a general user to execute operation for
the reasons of:
[0016] it is necessary to strip an inner lining of the vehicle;
[0017] wiring of the signal cable differs by vehicle kind;
[0018] it is necessary to find the signal cable from a number of
similar cables.
[0019] Therefore, sales routes of navigation apparatus are limited
to special stores and expensive attaching fee is needed, which
constitutes factors for hampering spread of the navigation
apparatus.
[0020] Further, in the case of the method in item (2), a power
supply cable and a signal cable are needed for the magnetic sensor
and these cables must be led between the magnetic sensor arranged
at outside of the vehicle and the navigation apparatus arranged at
inside of the vehicle, and so the operation requires time and
labor. Further, since tire cannot be magnetized strongly, the
magnetic sensor for detecting the magnetism needs to be provided
with high sensitivity. As a result, error is increased when the
vehicle is passing a steel bridge or traveling at a vicinity of a
railroad.
SUMMARY OF THE INVENTION
[0021] It is an object of the invention to solve the
above-described problem.
[0022] According to an aspect of the invention, there is provided,
for example, a detecting apparatus of vehicle speed comprising:
[0023] detecting means for emitting an electromagnetic wave or an
ultrasonic wave to a road surface and detecting traveling speed of
a vehicle from the Doppler effect produced in a reflected wave
thereof;
[0024] a transmitting circuit for sending information about the
traveling speed detected by the detecting means by radio;
[0025] a power generation mechanism for generating power by
vibration produced in the vehicle; and
[0026] a charging circuit for charging a charging type battery by
an output voltage of the power generation mechanism;
[0027] wherein voltage of the charging type battery is supplied to
the detecting means and the transmitting circuit as operating
voltage thereof.
[0028] Therefore, it is not necessary to connect a power supply
cable to the speed detecting apparatus, and it is not necessary to
connect a cable for informing the navigation apparatus of the
detected traveling speed, and so the transmission becomes wireless.
Accordingly, attachment of the speed detecting apparatus to the
vehicle is simplified. Further, it is not that the sales routes are
limited to special stores or expensive attachment fee is needed as
in the conventional navigation apparatus, and the speed detecting
apparatus can be sold in a general household electric appliance
store and is expedited to spread. Further, detection of vehicle
speed can be carried out with high accuracy.
[0029] Further, when the vehicle is disposed in a garage or a
parking lot and does not travel, consumption of the charging type
battery constituting a source of operating voltage can be
saved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 is a system diagram showing a prior art;
[0031] FIG. 2 is a system diagram showing an embodiment of the
invention; and
[0032] FIG. 3 is a waveform diagram for explaining the
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] In FIG. 2, reference numeral 30 designates an example of a
speed detecting apparatus according to the invention and reference
numeral 100 designates an example of a navigation apparatus using
the speed detecting apparatus. In this case, as shown by a chained
line, a total of the detecting apparatus 30 is contained in one
box-like member 39 and is attached to a portion of the vehicle
opposed to a surface of a road on which the vehicle travels, that
is, a road surface R, for example, a under surface of a floor of a
vehicle body.
[0034] Further, according to the detecting apparatus 30, a signal
of a millimeter wave of, for example, 70 GHz is formed by a forming
circuit 31, the millimeter wave is emitted from an antenna 32
obliquely toward the road surface R, a reflected wave of the
millimeter wave from the road surface R is received by the antenna
32 and a received signal thereof is supplied to a detecting circuit
33 and a detected signal SPD indicating a relative speed of the
vehicle body, that is, the vehicle relative to the road surface R
is outputted from the Doppler effect produced in the reflected
wave.
[0035] Further, as shown in, for example, FIG. 3, the detected
signal SPD is converted into a square wave signal the frequency of
which is changed in proportion to the speed. Further, the detected
signal SPD is supplied to a transmitting circuit 34 as a modulated
signal and as shown in, for example, FIG. 3, there is formed a PAM
(Pulse Amplitude Modulation) signal STX and the PAM signal STX is
supplied to an antenna 35 and transmitted to the navigation
apparatus 100.
[0036] Further, the detecting apparatus 30 is provided with a power
generation mechanism 36. That is, a permanent magnet 62 is attached
to an inner portion of the box-like member 39 by way of a spring 61
in a strip-like shape or a coil-like shape and the magnet 62 is
held such that the magnet 62 can be vibrated in a direction
indicated by an arrow relative to the box-like member 39. Further,
a coil 63 for power generation is provided at a position opposed to
the magnet 62. Therefore, when the vehicle travels, the magnet 62
is vibrated mainly in the direction indicated by an arrow by
vibration of the vehicle and alternating current voltage VAC is
generated in the coil 63.
[0037] Here, the alternating current voltage VAC is supplied to a
power supply circuit 37. That is, the alternating current voltage
VAC is supplied to a charging circuit 71 and rectified and elevated
and converted into direct current voltage VDC having a
predetermined magnitude, and the voltage VDC is supplied to a
charging type battery 72 such as a lithium ion battery or a lithium
polymer battery as charge voltage thereof. Therefore, when the
vehicle travels, the voltage VAC is generated and the battery 72 is
charged by the voltage VDC.
[0038] Further, the voltage VDC of the battery 72 is supplied to
the circuits 32 through 34 via a switching circuit 73 for power
saving as operating voltage of these. Further, voltage VAV produced
by rectifying the alternating current voltage is outputted from the
charging circuit 71 and the voltage VAV is supplied to a detecting
circuit 74 and the magnitude of the voltage VAV is detected.
Further, a detected output thereof is supplied to the switch
circuit 73 as a control signal and the switching circuit 73 is
turned on when VAV>VTH (VTH is predetermined voltage value) and
is turned off when VAV VTH. Further, the voltage VTH is a voltage
value in the case in which, for example, even when the alternating
current voltage VAC is provided, the voltage VAV is low and voltage
for charging the battery 72 is not provided from the charging
circuit 71.
[0039] Meanwhile, according to the navigation apparatus 100, the
vehicle speed sensor 26 is provided with an antenna 261 and a
receiving circuit 262. Further, the signal STX transmitted from the
antenna 35 is received by the antenna 261 and supplied to the
receiving circuit 262, the original detected signal SPD is
demodulated by and outputted from the receiving circuit 262 and the
outputted signal SPD is supplied to CPU 11 via the bus 19.
[0040] Further, other constituent portions such as ROM 12, RAM 13
and the like are connected to the system bus 19 similar to FIG. 1
although an explanation thereof will be omitted.
[0041] Further, the navigation apparatus 100, particularly LCD 18
thereof is provided at, for example, a dashboard.
[0042] According to the constitution, when the vehicle travels, the
voltage VAC is outputted from the coil 63 and when VAV>VTH, the
battery 72 is charged by the charging circuit 71, the switching
circuit 73 is turned on by the detected output from the detecting
circuit 74 and therefore, the voltage VDC of the battery 72 is
supplied to the circuits 32 through 34 by way of the switching
circuit 73 as operating voltage of these.
[0043] Therefore, the detected signal SPD detecting the speed of
the vehicle at this occasion is outputted from the detecting
circuit 33 and the signal SPD is transmitted to the navigation
apparatus 100 by the transmitting circuit 34. Further, in the
navigation apparatus 100, the signal SPD transmitted from the
detecting apparatus 30 is outputted from the receiving circuit 262
and is inputted to CPU 11. Therefore, the navigation apparatus 100
can be informed correctly of the traveling speed of the vehicle and
can execute correct navigation.
[0044] Further, when the voltage VAC is not provided since the
vehicle is disposed in a garage or a parking lot and does not
travel, or even when the voltage VAC is provided, in the case in
which the voltage is low and VAC.ltoreq.VTH, the switching circuit
73 is turned off and accordingly, there is brought about a power
saving state and the voltage VDC of the battery 72 is not
consumed.
[0045] In this way, according to the above-described detecting
apparatus 30, the traveling speed of the vehicle can be detected
and informed to the navigation apparatus 100. At this occasion,
operating voltage necessary for the detecting apparatus 30 is
provided by generating power with the magnet 62 and the coil 63.
Accordingly, it is not necessary to supply the operating voltage
from a car battery to the detecting apparatus 30 and therefore, it
is not necessary to connect a power supply cable to the detecting
apparatus 30.
[0046] Further, the traveling speed detected by the detecting
circuit 33 is informed to the navigation apparatus 100 by radio,
and so it is not necessary to connect a cable for informing the
traveling speed between the detecting circuit 33 and the navigation
apparatus 100.
[0047] Therefore, it is apparent also from FIG. 2, the detecting
apparatus 30 becomes wireless and therefore, when the detecting
apparatus 30 is attached, time and labor for stripping an inner
lining of the vehicle and finding a necessary cable from a number
of similar cables, is dispensed with and the detecting apparatus 30
can simply be attached to the vehicle. That is, the box-like member
39 containing the speed detecting apparatus 30 may only be attached
to the under surface of the floor of the vehicle body.
[0048] Further, since the attachment is simple in this way, as in a
conventional navigation apparatus, the sales routes are not limited
to special stores and expensive attachment fee is not needed, the
detecting apparatus 30 and the navigation apparatus 100 can be sold
in a general household electric appliance store and expedited to
spread.
[0049] Further, since the relative speed of the vehicle is detected
from the Doppler effect produced in the reflected wave of the
millimeter wave and therefore, even when the vehicle is passing
through a tunnel or a steel bridge or running at a vicinity of
railroad, the error is not increased.
[0050] Further, although in the above-described, the speed of the
vehicle is detected by using the millimeter wave, electromagnetic
wave such as light, ultrasonic wave or the like can also be used.
Further, when VAV.ltoreq.VTH, in the case in which the switching
circuit 73 is not immediately turned off and the state of
VAV.ltoreq.VTH continues over a predetermined time period, the
switch circuit 73 can be turned off. Similarly, in the state of
VAV>VTH continues over a predetermined time period, the
switching circuit 73 can be turned on.
[0051] Further, ON/OFF of the switching circuit 73 may be provided
with a hysteresis characteristic and when VAV.ltoreq.VTH1, the
switching circuit 73 can be turned off and when VAV>VTH2
(VTH2>VTH1), the switching circuit 73 can be turned on.
[0052] Further, although according to the above-described power
generation mechanism 36, power is generated by vibration of the
magnet 62 in the vertical direction, power can be generated also by
vibration in a horizontal direction or a front and rear direction.
Further, power can be generated by increasing the vibration of the
magnet 62 by using gears or the like.
* * * * *