Patent Application
20200371133
The present invention relates a multi-speed meter capable of measuring a wind speed with a self-correction function, a wind speed measuring method with a self-correction function, and a moving apparatus having a multi-speed meter installed therein, and more particularly, to a multi-speed meter capable of measuring a wind speed with a self-correction function, which is installed on a ground-based moving apparatus significantly affected by a wind speed such as a bicycle or motorcycle to measure a wind speed and correct a wind speed that may occur due to an occupant, a wind speed measuring method with a self-correction function, and a moving apparatus having a multi-speed meter installed therein.
A ground-based moving apparatus such as a car or motorcycle is equipped with a separate speedometer to guide a speed of the ground-based moving apparatus to a driver. Unlike cars or motorcycles, ground-based moving apparatus, such as bicycles without a separate internal combustion engine or system, may have a sensor attached to a side of a wheel to measure a magnetic field and a magnet attached to the wheel or a fork to calculate a speed of the ground-based moving apparatus by measuring a speed at which a magnetic field is converted by a magnetic sensor or to measure the speed of the ground-based moving apparatus using a global positioning system (GPS) in an application installed in a mobile phone, which is a user's option, though.
An RPM speedometer and a GPS speedometer for measuring a rotational speed of the wheel described above are disclosed in Korean Patent Laid-Open Publication No. 10-2009-0109247 (“Speed indicator for correcting error and method thereof” published on Oct. 20, 2009, Related Art 1). Both the RPM speedometer and the GPS speedometer disclosed in Related Art 1 measure an absolute speed of a moving apparatus, and the absolute speed measured in this way is problematic in that it does not consider a wind pressure acting on a driver due to wind when the driver is exposed to the outside such as a bicycle or a motorcycle among ground-based moving apparatus.
Meanwhile, in an aircraft, a relative speed is measured using a pressure speedometer. Since the pressure speedometer measures a total pressure and a static pressure and then calculates the relative speed of the aircraft using a difference between the total pressure and the static pressure, a wind pressure acting on the aircraft is considered.
The aircraft using the pressure speedometer may obtain an accurate relative speed because distortion of the total pressure and static pressure is not large, but in the case of the ground-based moving apparatus, in particular, a bicycle or motorcycle, a relative speed measured by the pressure speedometer includes an error due to different outer appearances based on accessories such as a bag attached to a body of the ground-based moving apparatus or a posture of an occupant. Therefore, the measured relative speed needs to be corrected to apply the pressure speedometer to the ground-based moving apparatus such as a bicycle or motorcycle.
An object of the present invention is to provide a multi-speed meter capable of measuring a wind speed with a self-correction function, a wind speed measuring method with a self-correction function, and a moving apparatus having a multi-speed meter installed therein, which are installed on a ground-based moving apparatus such as a bicycle or a motorcycle in which a driver is exposed to the outside to provide information such as an absolute speed, a relative speed, and a wind speed to the driver and which are capable of correcting the relative speed considering distortion that may occur in the bicycle or the motorcycle.
In one general aspect, a multi-speed meter capable of measuring a wind speed with a self-correction function includes: an absolute speedometer installed on a moving apparatus and measuring an absolute speed; a relative speedometer installed on the moving apparatus and measuring a relative speed; and a controller outputting the measured absolute speed and the relative speed transmitted from the absolute speedometer and the relative speedometer and outputting a wind speed which is a difference between the absolute speed and the relative speed.
The controller may derive a correction equation using a relationship between an absolute speed and a relative speed measured during a predetermined time in which the moving apparatus travels in an environment where wind does not blow, and output a relative speed corrected using the correction equation and a wind speed.
The absolute speedometer may include at least one selected from among an RPM speedometer, a GPS speedometer, a gyro sensor, and an acceleration sensor.
The controller may selectively output an absolute speed measured by each speedometer or sensor or output an average of all measured absolute speeds, when the absolute speedometer includes two or more of the RPM speedometer, the GPS speedometer, the gyro sensor, and the acceleration sensor.
The relative speedometer may be a pressure speedometer or an ultrasonic speedometer.
The relative speedometer may be integrated with the controller or may be separately installed on the moving apparatus.
The GPS speedometer may be integrated with the controller or separately installed on the moving apparatus, when the GPS speedometer is included in the absolute speedometer.
The pressure speedometer may include: a total pressure measuring unit installed toward a front of the moving apparatus to measure a total pressure; and a static pressure measuring unit installed on a side of the total pressure measuring unit.
The multi-speed meter may further include: a multi-speed meter body including the controller and an output unit outputting information received from the controller.
The multi-speed meter body may be a smart device.
In another general aspect, a wind speed measuring method with a self-correction function includes: an absolute speed measuring operation of measuring an absolute speed of a moving apparatus; a relative speed measuring operation of measuring a relative speed of the moving apparatus with wind around the moving apparatus; and a wind speed outputting operation of outputting a wind speed which is a difference between the absolute speed measured in the absolute speed measuring operation and the relative speed measured in the relative speed measuring operation.
The wind speed measuring method may further include: an absolute speed and relative speed outputting operation of outputting the absolute speed and the relative speed measured in the absolute speed measuring operation and the relative speed measuring operation, respectively, the absolute speed and relative speed outputting operation being performed after the absolute speed measuring operation and the relative speed measuring operation.
The wind speed outputting operation may include deriving a correction equation using a relationship between an absolute speed and a relative speed measured during a predetermined time in which the moving apparatus travels in an environment where wind does not blow, and outputting a relative speed corrected using the correction equation and a wind speed.
The multi-speed meter capable of measuring a wind speed with a self-correction function may be installed on a moving apparatus, and the moving apparatus may be a bicycle, a motorcycle, or a personal mobility device.
According to the multi-speed meter capable of measuring a wind speed with a self-correction function, a wind speed measuring method with a self-correction function, and a moving apparatus having a multi-speed meter installed therein according to various exemplary embodiments of the present invention, since an absolute speed and a relative speed are measured by the absolute speedometer and the relative speedometer measure, respectively, and a wind speed is calculated using a difference between the two speeds, a driver of a moving apparatus such as a bicycle, a motorcycle, or a personal mobility device in which a driver is exposed to the outside may easily adjust a speed and a pace of the moving apparatus according to a wind speed.
In addition, according to the present invention, in order to correct a distorted relative speed according to an external shape (appearance), a correction equation of an absolute speed and the relative speed while a moving apparatus travels in an environment without wind is obtained, and a corrected relative speed and a wind speed are then measured using the obtained correction equation in a real-usage environment, thereby providing a more accurate wind speed to the driver.
Hereinafter, exemplary embodiments of a multi-speed meter capable of measuring a wind speed with a self-correction function according to the present invention will be described in detail with reference to the accompanying drawings.
As shown in
In addition, various absolute speedometers such as the RPM speedometer, the GPS speedometer, the gyro sensor, or the acceleration sensor described above may be used independently alone or a combination of a plurality thereof may also be used. In one exemplary embodiment of the present invention illustrated in
The RPM speedometer may be implemented in various ways. In the present invention, the RPM speedometer may include a magnetic sensor 110 installed on a chain stay 11 located at a rear of a frame of a bicycle to measure a change in a magnetic field and a magnet (not shown) installed on a wheel or a fork as shown in
An absolute speed of the moving apparatus measured in the RPM speedometer and GPS speedometer, i.e., the absolute speed of the bicycle 10, is transmitted to a controller to be described later, and the RPM speedometer and GPS speedometer may include various wireless communication units such as ZigBee or Bluetooth or may be connected to the controller through wires to transmit the measured absolute speed of the moving apparatus to the controller.
A relative speedometer measures a relative speed of the moving apparatus with wind blowing around the moving apparatus.
The relative speedometer measures the relative speed of the moving apparatus with wind blowing around the moving apparatus in various ways, and a representative method of the relative speedometer may include a pressure speedometer 200 illustrated in
The pressure speedometer 200 is installed on the moving apparatus to measure the relative speed of the moving apparatus and includes a total pressure measuring unit 210 installed toward a front of the moving apparatus to measure a total pressure and a static pressure measuring unit 220 installed on a side of the total pressure measuring unit 210 to measure a static pressure.
The total pressure measuring unit 210 serves to measure a total pressure which is a pressure received from air as the bicycle 10 travels. The total pressure measuring unit 210 may be installed in the form of a probe so that a total pressure hole (not shown) faces forward as shown in
The static pressure measured by the static pressure measuring unit 220 refers to a pressure when there is no flow of a fluid or without considering a flow of a fluid, and is determined by temperature and air density. It is important for the static pressure measuring unit 220 itself to be installed on a portion where an influence of external air is minimized, and to this end, as shown in
As shown in
Only a single static pressure measuring unit 220 may not be installed but a plurality of static pressure measuring units 220 may be installed around the bicycle 10 to increase precision of the measured static pressure. For example, the static pressure measuring unit 220 may be installed on both sides of the bicycle in the moving direction of the bicycle 10.
The ultrasonic speedometer is a speedometer to measure a speed using a passage time of an ultrasonic wave and uses a principle that the passage time of the ultrasonic wave is faster than a reference time if a moving direction of the ultrasonic wave is the same as that of air and the passage time of the ultrasonic wave is slower than the reference time if the moving direction of the ultrasonic wave is the opposite to the moving direction of air.
The ultrasonic speedometer includes a pair of members for transmitting and receiving an ultrasonic wave or transmitting, reflecting, and receiving an ultrasonic wave. The pair of members are arranged to surround a specific space to measure a wind direction and a wind speed through a vector sum of each speed. When the ultrasonic speedometer is installed as a relative speedometer at the ground-based moving apparatus as in the present invention, a relative speed of the moving apparatus with ambient wind may be measured.
Although the pressure speedometer 200 and the ultrasonic speedometer as the relative speedometer described above may be used independently, or alternatively, the pressure speedometer 200 and the ultrasonic speedometer may be used together and an average of relative speeds measured by the pressure speedometer 200 and the ultrasonic speedometer may be used to increase accuracy of the measured relative speeds.
The controller (not shown) receives the absolute speed and the relative speed respectively measured by the absolute speedometer and the relative speedometer 200 and outputs them as they are or performs a predetermined correction thereon and outputs corrected speeds. In addition, the controller may obtain a difference between the absolute speed and the relative speed of the moving apparatus and output the difference as a wind speed.
The controller may be implemented in the form of a program inside the multi-speed meter main body. In addition to the controller, the multi-speed meter main body may further include an output unit for outputting information (absolute speed, relative speed, wind speed) received from the controller. The output unit may be typically a display but various types of output units capable of transmitting information to the driver of the ground-based moving apparatus such as a voice output unit may be used.
Since the multi-speed meter main body only needs to include the controller and the output unit, any device including an MCU may be used. For example, a smart device 300 shown in
Referring to
The multi-speed meter main body described above may be replaced by a smart device equipped with a necessary program.
As described above in the background, when the driver applies the pressure speedometer to the ground-based moving apparatus such as a bicycle or a motorcycle in which the driver is exposed to the outside, a total pressure and a static pressure are significantly distorted due to a non-uniform shape of the ground-based moving apparatus, and thus, the total pressure and the static pressure need to be corrected. Test traveling for correction may be performed for a predetermined time, and a separate button for determining ON/OFF of the test traveling for correction may be implemented as a mechanical button or a touch screen at the multi-speed meter main body or as a touch screen at the smart device 300 and installed on the bicycle.
The test traveling for correction may be conducted in an environment in which a wind speed needs not be considered, that is, in an environment where wind does not blow.
First in a wind-free environment, the driver rides on the bicycle equipped with the multi-speed meter capable of measuring a wind speed with a self-correction function based on the present invention, presses an ON button of the test traveling, and then slowly accelerates to a maximum speed in a stop state, while keeping a steady posture. Since wind does not blow in the traveling environment, an absolute speed and a relative speed measured by the absolute speedometer and the relative speedometer should be the same but distortion occurs due to the shape of the bicycle and the driver. In this case, it is considered that the distortion has occurred in the relative speed measured by the relative speedometer, and a relational expression between the absolute speed measured up to a maximum speed based on the absolute speed as a constant and the relative speed is derived. As the relational expression, a method such as a linear correction formula using a least square method and a multi-order function correction formula may be used due to a curve fitting problem based on data of the absolute speed and relative speed.
Specifically, m data sets of absolute speeds (yi) and relative speeds (xi) may be expressed by the least square method of (n−1)-th order polynomial as follows.
In the above formula, Xij is a polynomial j term of an i-th relative speed and Xi1=1, Xi2=xi, Xi3=xî2, Xin=xîn−1, and Bj is a coefficient of j term of the (n−1)-th order correction formula, and a determinant thereof is as follows.
If n>m in the above formula, there is no solution, if n=m, there is only one solution, and if n<m, there is no solution that satisfies all data but the coefficient Bj of the polynomial that minimizes the square of an error is obtained as follows.
{circumflex over (β)}=(XTX)−1 XTy.
In order to apply the corrected equation to the relative speed measurement in traveling, the order (n−1) of correction equation or correction test data set (m) need to be determined so as to satisfy the condition of n<m.
Since the measured relative speed Vp includes distortion due to the appearance of the moving apparatus body and the driver, the measured relative speed is corrected using the relational expression derived from the wind-free environment.
In
Hereinafter, a wind speed measuring method with a self-correction function according to the present invention will be described in detail.
The wind speed measuring method with a self-correction function according to an exemplary embodiment of the present invention may include an absolute speed measurement step, a relative speed measurement step, and a wind speed output step.
The absolute speed measurement step is to measure an absolute speed of a moving apparatus. The absolute speed measurement step may be performed by an absolute speedometer installed on the moving apparatus included in the multi-speed meter described above.
The relative speed measurement step is to measure a relative speed of the moving apparatus with wind around the moving apparatus. The relative speed measurement step may be performed by a relative speedometer installed on the moving apparatus included in the multi-speedometer described above.
The wind speed output step is to output a wind speed which is a difference between the absolute speed measured in the absolute speed measurement step and the relative speed measured in the absolute speed measurement step. The wind speed output step may be performed by a controller installed on the moving apparatus included in the multi-speed meter described above.
The present invention may further include an absolute speed and a relative speed output step in addition to the three steps described above. That is, in the present invention, the controller may not simply output the wind speed in the wind speed output step but may also output an absolute speed and a relative speed, thereby providing the absolute speed, the relative speed, and the wind speed of the moving apparatus as information required for the operation to the driver of the moving apparatus.
The wind speed output in the wind speed output step may be a corrected speed. This is because the measured wind speed may be distorted as the driver of the moving apparatus such as a bicycle, a motorcycle, a personal mobility device is exposed to the outside and due to an appearance varied depending on various accessories installed on the moving apparatus.
The specific method for correcting the wind speed in the wind speed output step may be a method of deriving a correction formula using a relation between the absolute speed and the relative speed measured for a predetermined time in which the moving apparatus travels in an environment without wind, and outputting the corrected relative speed and the wind speed using the correction formula.
It will be obvious to those skilled in the art to which the present invention pertains that the present invention described above is not limited to the above-mentioned exemplary embodiments and the accompanying drawings, but may be variously substituted, modified, and altered without departing from the scope and spirit of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2017-0104242 | Aug 2017 | KR | national |
The present application is a U.S. National Phase of International Patent Application Serial No. PCT/KR2018/009429 entitled “MULTI-SPEED METER CAPABLE OF PERFORMING WIND SPEED MEASUREMENT HAVING SELFCORRECTION FUNCTION, WIND SPEED MEASUREMENT METHOD HAVING SELF-CORRECTION FUNCTION, AND TRAVELING OBJECT HAVING MULTI-SPEED METER INSTALLED THEREIN,” filed on Aug. 17, 2018. International Patent Application Serial No. PCT/KR2018/009429 claims priority to Korean Patent Application No. 10-2017-0104242 filed on Aug. 17, 2017. The entire contents of each of the above-referenced applications are hereby incorporated by reference for all purposes.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2018/009429 | 8/17/2018 | WO | 00 |
