Patent Publication Number: US-2022234398-A1

Title: Multi-antenna tire-pressure monitoring system with automatically positioning function

Description:
BACKGROUND OF THE INVENTION 
       1 . Field of the Invention 
     The present invention is related to a multi-antenna tire-pressure monitoring system with automatically positioning function and applied to a technology field of vehicle. The present invention mainly applies a difference in the phase angles between the tire-pressure sensor installed on the tire and the antennas to calculate relative angles, so as to accurately determine horizontal positions and longitude positions of the tires, and determine whether the positions of the tires are accurate. 
     2. Description of the Related Art 
     In recent years, traffic safety is taken seriously, so walking pedestrians or drivers must follow many traffic rules, and, new delivered vehicles and small trucks must be equipped with tire pressure monitoring systems (TPMS), in order to improve safety of pedestrian and ensure the stability of the vehicle at high speed. 
     In the process of production and assembly, the vehicle factory installs tire-pressure sensors on tires, and the tire-pressure sensor is able to sense information of the tire such as pressure, temperature or battery power and provide the information to the driver when the vehicle is driving on the road in the future. Therefore, in order to install the tire-pressure sensors, the tire-pressure sensors must be adjusted and set to correspond the positions of the tires through multiple processes, so that the installed tire-pressure sensors are able to sense the tires when the vehicle is driving in the future. Generally, there are two existing methods for setting the tire-pressure sensors, the first existing method is manual input, a user holds a host to read the tires one by one and inputs data through on-board diagnostics (OBD II) interface in sequence, and the user must manually determine the inputted positions of the tires relative to the vehicle carefully. Obviously, the manual input method is very inconvenient. 
     The second existing method is an automatically-positioning method. The tire-pressure sensors can be classified into inside-type sensors and outside-type sensors, the inside-type sensor has a fixed installation direction, so the receiver receives data of X-axis and Z-axis accelerators on the inside-type sensor and calculates the position of the tire with algorithm. The automatically-positioning method can be implemented by a wireless auto location (WAL) method or a phase auto location (PAL) method. The WAL method uses X-axis rotation direction to determine the horizontal positions of tires and uses the signal strength to determine the longitudinal positions of the tires, so as to position the tires. In the PAL method, a rotation angle of the tire is obtained by ABS and then compared with RF transmission time to obtain a phase angle difference of the rotating rim, thereby calculating the position of the tire. When installing the tire-pressure sensor by the WAL or PAL method, the X-axis of the tire-pressure sensor must be parallel to a driving direction and the Z-axis of the tire-pressure sensor must be perpendicular to the driving direction for accurate calculation of the acceleration. However, for outside-type tire-pressure sensors, the angles of valves are different and the rotation angles after assembly are not constant, so the data of the X-axis and Z-axis sensor of the outside-type tire-pressure sensor cannot be used in the PAL method for positioning the tires. 
     Therefore, if the tire-pressure sensor fails to accurately position the tires after the above-mentioned vehicle assembly process, the tire-pressure monitoring system may continuously detect the tire with error while the vehicle is driving, and it causes the vehicle to have a very high risk in driving. 
     SUMMARY OF THE INVENTION 
     An objective of the present invention is to apply tire-pressure sensors to position tires by a quicker and more accurate manner, so as to solve the above-mentioned conventional technology drawbacks and problems. 
     In order to achieve the objective, the present invention provides a multi-antenna tire-pressure monitoring system with automatically positioning function, and the multi-antenna tire-pressure monitoring system includes tire-pressure sensors, a receiver, and a central processing unit. The tire-pressure sensors are installed on tires of a vehicle, respectively, one of the tires is installed with at least one of the tire-pressure sensors, and each of the tire-pressure sensors includes a signal transmitting unit built therein. The receiver includes two antennas, and a receiver control unit built therein, wherein the two antennas are spaced by an interval and configured to receive signals transmitted from the tire-pressure sensors, a first phase angle and a second phase angle are formed between the signal transmitted from each of the tire-pressure sensors and the two antennas, respectively, wherein the receiver control unit receives the first phase angle and the second phase angle, and the arithmetic unit calculates phase-difference parameter values based on the first phase angle and the second phase angle, the receiver control unit calculates relative angles between the tire-pressure sensors and the receiver based on the phase-difference parameter values, to determine horizontal and longitudinal positions of the tires. The central processing unit includes a signal receiving unit built therein, and the signal receiving unit is configured to receive and display information calculated by the arithmetic unit of the receiver. The two antennas receive the signal transmitted from each of the tire-pressure sensors to form the first phase angle and the second phase angle, the arithmetic unit calculates a phase difference between the first phase angle and the second phase angle to form the phase-difference parameter value, the receiver control unit accurately determines the horizontal and longitudinal positions of the tires based on the phase-difference parameter values. 
     According to aforementioned contents that the two antennas are configured to obtain the first phase angle and the second phase angle of each tire-pressure sensors installed on each tire and the arithmetic unit calculates the phase differences to obtain the different phase-difference parameter values, and then calculates the relative angles between the tire-pressure sensors and the receiver based on the phase-difference parameter values, so as to determine the positions of the tires based on the relative angles. Therefore, the present invention has advantages of quickly precisely positioning the tires and preventing the error caused by manual input manner. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The structure, operating principle and effects of the present invention will be described in detail by way of various embodiments which are illustrated in the accompanying drawings. 
         FIG. 1  is a block diagram of the present invention. 
         FIG. 2  is a schematic view showing a positional relationship between antennas and a tire-pressure sensor installed on a bottom left tire and located at an initial position, according to the present invention. 
         FIG. 3  is a schematic view showing a positional relationship between antennas and a tire-pressure sensor installed on a top left tire and located at an initial position, according to the present invention. 
         FIG. 4  is a schematic view showing a positional relationship between antennas and a tire-pressure sensor installed on a bottom right tire and located at an initial position, according to the present invention. 
         FIG. 5  is a schematic view showing a positional relationship between antennas and a tire-pressure sensor installed on a top right tire and located at an initial position, according to the present invention. 
         FIG. 6  is a schematic view showing a positional relationship between antennas and a tire-pressure sensor installed on a bottom left tire and located at an extremely-close position and an extremely-far position while the tire is rotating, according to the present invention. 
         FIG. 7  is a schematic view showing a positional relationship between antennas and a tire-pressure sensor installed on a top left tire at an extremely-close position and an extremely-far position while the tire is rotating, according to the present invention. 
         FIG. 8  is a schematic view showing a positional relationship between antennas and a tire-pressure sensor installed on a bottom right tire at an extremely-close position and an extremely-far position while the tire is rotating, according to the present invention. 
         FIG. 9  is a schematic view showing a positional relationship between antennas and a tire-pressure sensor installed on a top right tire and located at an extremely-close position and an extremely-far position while the tire is rotating, according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following embodiments of the present invention are herein described in detail with reference to the accompanying drawings. These drawings show specific examples of the embodiments of the present invention. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. it is to be acknowledged that these embodiments are exemplary implementations and are not to be construed as limiting the scope of the present invention in any way. Further modifications to the disclosed embodiments, as well as other embodiments, are also included within the scope of the appended claims. 
     These embodiments are provided so that this disclosure is thorough and complete, and fully conveys the inventive concept to those skilled in the art. Regarding the drawings, the relative proportions and ratios of elements in the drawings may be exaggerated or diminished in size for the sake of clarity and convenience. Such arbitrary proportions are only illustrative and not limiting in any way. The same reference numbers are used in the drawings and description to refer to the same or like parts. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms, as well, unless the context clearly indicates otherwise. 
     It is to be acknowledged that, although the terms ‘first’, ‘second’, ‘third’, and so on, may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only for the purpose of distinguishing one component from another component. Thus, a first element discussed herein could be termed a second element without altering the description of the present disclosure. As used herein, the term “or” includes any and all combinations of one or more of the associated listed items, 
     It will be acknowledged that when an element or layer is referred to as being “on,” “connected to” or “coupled to” another element or layer, it can be directly on, connected or coupled to the other element or layer, or intervening, elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly connected to” or “directly coupled to” another element or layer, there are no intervening elements or layers present. 
     In addition, unless explicitly described to the contrary, the words “comprise” and “include”, and variations such as “comprises”, “comprising”, “includes”, or “including”, will be acknowledged to imply the inclusion of stated elements but not the exclusion of any other elements. 
     In order to clearly describe the objective of the present invention, the features and effects of the present invention are illustrated in detail with reference to embodiments. Please refer to  FIGS. 1 to 9 . As shown in  FIG. 1 , a multi-antenna tire-pressure monitoring system includes tire-pressure sensors  1  installed on tires  10  of a vehicle, respectively, and each tire  10  is installed with at least one tire-pressure sensor  1 . Each of the tire-pressure sensors  1  includes a signal transmitting unit  11  built therein, a receiver  2 , and a central processing unit  3 . In figures of the present invention, the receiver  2  is installed on the rear end of a vehicle for illustration, but the installation position of the receiver  2  of the present invention is not limited to the example. The receiver  2  includes two antennas  21  and built-in receiver control unit  22 , the two antennas  21  are disposed at the same horizontal levels and with the same heights, and spaced apart from each other by a certain interval. The two antennas  21  receive signals transmitted from the signal transmitting units  11  of the tire-pressure sensors  1 . A first phase angle Θ 1  and a second phase angle Θ 2  are formed between the signal transmitted from each of the tire-pressure sensors  1  and the two antennas  21 , respectively, and the receiver control unit  22  receives the first phase angle Θ 1  and the second phase angle Θ 2 . The arithmetic unit  23  performs calculation to obtain phase-differences parameter values, the receiver control unit  22  determines the horizontal and longitude positions of the tires  10  based on the phase-difference parameter values. The central processing unit  3  includes a signal receiving unit  31  built therein and configured to receive and display the information calculated by the arithmetic unit  23  of the receiver  2 . The two antennas  21  receive the signals transmitted from the tire-pressure sensor  1 , to form the first phase angle Θ 1  and the second phase angle Θ 2 , and the arithmetic unit  23  calculates the phase difference between the first phase angle Θ 1  and the second phase angle Θ 2 , so as to obtain the phase-difference parameter values. The receiver control unit  22  can accurately determine the horizontal and longitude positions of the tires  10 . 
     Please refer to  FIGS. 1 to 9 . The embodiment of single tire  10  will be illustrated in the following paragraphs according to aforementioned contents,  FIGS. 2 to 5  shows four tires  10  which are respectively labelled as “A” (bottom left), “B” (top left), “C” (bottom right), and “D” (top right) for convenience in explanation. Each of the tires  10  is installed with one of the tire-pressure sensors  1 , and the tire-pressure sensors  1  are labelled as “A 1 ”, “B 1 ”, “C 1 ”, “D 1 ” corresponding to the labels of the tires, respectively. The positioning operation of the present invention is illustrated under the condition that the tires  10  are not deflected, as shown in.  FIG. 2 , when the tire  10  (labelled as “A 1 ”) is not rotated, the position of the tire-pressure sensor  1  (labelled as “A 1 ”) is defined as an initial position  4 , the tire-pressure sensor  1  (labelled as “A 1 ”) transmits signal to the receiver  2  through the signal transmitting unit  11 , the two antennas  21  (labelled as X and Y, respectively) disposed in the receiver  2  receive the signal. With the configuration of the antenna  21  (labelled as X) and the antenna  21  (labelled as Y) spaced apart from each other by the interval, the receiver  2  obtains the first phase angle Θ 1  between the tire-pressure sensor  1  (labelled as A 1 ) and the antenna  21  (labelled as X), and the second phase angle Θ 2  between the tire-pressure sensor  1  (labelled as A 1 ) and the antenna  21  (labelled as Y), and the first phase angle Θ 1  is smaller than the second phase angle Θ 2 . After the receiver control unit  22  obtains the values of the first phase angle Θ 1  and the second phase angle Θ 2 , the arithmetic unit  23  built in the receiver  2  can calculate the phase-difference parameter values, and the obtained phase-difference parameter values are dedicated data of the tire  10  (labelled as A), and the arithmetic unit  23  transmits the calculated phase-difference parameter values to the central processing unit  3 . The central processing unit  3  processes and converts the signal received by the signal receiving unit  31 , to accurately position the tire  10  (labelled as “A”), so that the driver can obtain the current situation of the tire  10  (labelled as “A”); as shown in  FIG. 2 , the tires (labelled as “A” and “C”) are determined as left and right tires based on signal transmission; the signal transmission is also occurred at another tires  10 , the dotted line indicates the signal transmission, and  FIGS. 3 and 5  shows the signal transmission in the way. 
     The manner of positioning another tires  10 , which are respectively labelled as “B”, “C” and “D”, is the same as above-mentioned manner. The above-mentioned positioning manner is mainly to determine the horizontals positions of the tires  10  relative to the vehicle, but unable to accurately determine the longitudinal positions of the tires  10 . In the present invention, the longitudinal positions of the tires  10  are accurately determined while the tires  10  are rotating. As shown in  FIG. 6 , while the tire  10  (labelled as “A”) is rotating, an extremely-close position  5  and an extremely-far position  6  of the tire-pressure sensor  1  (labelled as “A 1 ”) relative to the receiver  2  can be defined, respectively; when the tire-pressure sensor  1  (labelled as “A 1 ”) is at the extremely-close position  5 , the tire-pressure sensor  1  (labelled as “A 1 ”) transmits signal and the antenna  21  (labelled as “X”) and the antenna  21  (labelled as “Y”) of the receiver  2  receive the signal; when the tire-pressure sensor  1  (labelled as “A 1 ”) is at the extremely-far position  6 , the tire-pressure sensor  1  (labelled as “A 1 ”) transmits signal, and the antenna  21  (labelled as “X”) and the antenna  21  (labelled as “Y”) of the receiver  2  receive the signal. After the tire  10  (labelled as “A”) rotates and the receiver  2  receives and cumulate signals for a period, the arithmetic unit  23  can calculate the signals to obtain another phase-difference parameter values of the tire  10  (labelled as “A”), so as to position the longitudinal position of the tire  10 . As shown in  FIG. 7 , the first phase angles Θ 1  and the second phase angles Θ 2  shown in  FIG. 6  and  FIG. 7  are not the same, so that the longitudinal positions of the left tires  10  of the vehicle can be clearly determined; after the longitudinal position of the tire  10  (labelled as “A”) is determined and in corporation with the phase-difference parameter value generated by the manner of determining the horizontal position of the tire  10  (labelled as “A”), the tire  10  (labelled as “A”) can be accurately determined to locate at the bottom left position of the vehicle. As shown in  FIG. 6 , the tires  10  (labelled as “A” and “B”) are determined to be a front tire and a rear tire based on signal transmission; at the tire  10  (labelled as “A”), the signal transmission from the extremely-close position  5  is drawn by thick solid line, and the signal transmission from the extremely-far position  6  is drawn by thin solid line, signal transmission is also occurred at another tire  10 , and the dotted line indicates the signal transmission, and  FIGS. 6 to 9  show the signal transmission in the same way. 
     According to aforementioned illustration, the manner of positioning the remaining tires  10  (labelled as “B”, “C” and “D”) is the same as above-mentioned manner, the tire-pressure sensor  1  can transmit signal to the two antennas  21  at the initial position  4 , the extremely-close position  5  and the extremely-far position  6 , and the arithmetic unit  23  can calculate different. phase-difference parameter values based on the received signal, so that the position of the tire  10  can be accurately and quickly determined. The phase difference calculation is performed by the arithmetic unit based on the formula: θ=arccos((∅ λ)/(2πd)), θ is a relative angle between the tire-pressure sensor  1  and the receiver  2 , ψ is a phase difference, λ is wavelength of signal transmitted from the tire-pressure sensor  1  to the antenna  21 , and d is the distance between the two antennas  21 ; the calculation based on the above-mentioned formula can obtain accurate phase angle difference between the signals transmitted from the tire-pressure sensor  1  to the two antennas  21 , so that the receiver control unit  22  can determine the positions of the tires  10  based on the phase-difference parameter values. 
     Another detailed features of the present invention will be illustrated in the following paragraphs. Please refer to  FIG. 1 . The receiver  2  of the present invention includes an RF transceiver unit  24  built therein and configured to transmit signal. The RF transceiver unit  24  receives the signals of the tire-pressure sensors  1  and transmits the phase-difference parameter values calculated by the arithmetic unit  23  to the central processing unit  3 . In an embodiment, the central processing unit  3  of the present invention can be an electronic apparatus with a display screen, so that the central processing unit  3  can provide a driver or a user to check the result of positioning the tires  10 , and condition information of the tire  10  before positioning. Besides displaying the positioning status of the tires  10 , the central processing unit  3  of the present invention can display the detailed situations of the tires  10 ; for example, each tire-pressure sensor  1  can include a processing unit  12 , a pressure sensing unit  13 , a temperature sensing unit  14  and an acceleration sensing unit  15  built therein, the pressure sensing unit  13  senses a remaining pressure of the tire  10 , the temperature sensing unit  14  senses a temperature inside the tire  10 , the acceleration sensing unit  15  senses a rotation speed of the tire  10  while the tire  10  is rotating, and the processing unit  12  integrates the sensed pressure, temperature and the rotation speed, and transmits the integrated data to the receiver  2  through the signal transmitting unit II. The receiver  2  collects and converts the data, and then transmits the converted data to the central processing unit  3 , and the central processing unit  3  displays the received data to make the driver or the user obtain the relevant parameter values including pressure, temperature and acceleration, thereby ensuring driving safety, as shown in  FIG. 1 . 
     It is worth noting that the amount of the antennas  21  of the present invention can be more than two to more accurately position the tires, and the configuration of more antennas  21  can resist noise interference. in an embodiment, the antennas  21  can be arranged in a line, a matrix or a circle (not shown in figures). Therefore, the configuration of more antennas  21  can improve calculation accuracy to effectively position the tires  10 . 
     The present invention disclosed herein has been described by means of specific embodiments. However, numerous modifications, variations and enhancements can be made thereto by those skilled in the art without departing from the spirit and scope of the disclosure set forth in the claims.