JP2015131546A - Tire position registration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire position registration system which can further correctly determine a tire position.SOLUTION: A period calculation part 23 calculates one rotational period of an axle on the basis of a detection signal output from an axle detection part 22. A parameter calculation part 24 calculates determination parameters between respective peaks by dividing the one rotational period of the axle by gravity sampling interval time transmitted from a tire valve 4. An acceleration/deceleration determination part 25 determines acceleration/deceleration of a vehicle 1 by confirming change in time series of the determination parameters. A position determination part 26 executes determination of the tire position by considering the determination result of the acceleration/deceleration determination part 25.

Description

  The present invention relates to a tire position registration system for registering a tire valve ID in a receiver in association with a tire mounting position.

  2. Description of the Related Art Conventionally, as one function of a tire pressure monitoring system, a tire position registration system that automatically registers a tire valve ID (valve ID) in a receiver without using a trigger device such as an initiator is well known (Patent Document 1). Etc.). If the initiator is not required for registering the valve ID in the receiver, the number of components mounted on the vehicle can be reduced.

Special table 2011-527971 gazette

  By the way, in this type of tire position determination system, there is a need to determine the tire position more correctly. However, depending on the tire position determination method, there is a problem that the accuracy is inevitably deteriorated when the position determination is performed based on data when the vehicle is accelerated or decelerated.

  An object of the present invention is to provide a tire position registration system capable of more correctly determining a tire position.

  A tire position registration system that solves the above problems is necessary for transmitting a radio wave including tire pressure data from a tire valve of each tire, and monitoring the pressure of each tire by receiving the radio wave by a receiver of a vehicle body. Yes, in the configuration in which the ID of the tire valve is registered in the receiver in association with the tire position, the cycle per one rotation of the axle is determined based on the axle rotation information obtained from the axle rotation detection unit that can detect the rotation of the axle. A determination parameter is calculated based on a cycle calculation unit that can be calculated and executed over a plurality of rotations, a variable gravity sampling interval time that is an execution interval of gravity detection, and an axle one rotation cycle. A parameter calculation unit for determining the acceleration / deceleration of the vehicle from the change of the determination parameter, and the tire valve is a tire. A radio wave that is known to be located at a specific position in the rolling direction is transmitted from each tire valve and received by the receiver, and the axle rotation information of each axle when each tire valve takes the specific position is specified. A position determination unit that obtains a plurality of each position and confirms which axle rotation information the valve ID is synchronized with, and associates the valve ID and the axle to determine the tire position, The position determination unit determines a tire position based on a determination result of the acceleration / deceleration determination unit.

  According to this configuration, the calculation for determining the determination parameter is performed for each rotation period of the axle based on the one rotation period of the axle and the gravity sampling interval time, and the acceleration / deceleration is determined by checking the time series change of these determination parameters. To do. Based on the acceleration / deceleration determination result, the tire position is determined. Therefore, when determining the tire position and registering it in the receiver, it is possible to determine the position according to the acceleration / deceleration of the vehicle. Therefore, even if the vehicle is accelerating / decelerating, the tire position can be determined more correctly. It becomes.

  In the tire position registration system, it is preferable that the parameter calculation unit calculates the determination parameter by dividing the one axle rotation cycle by the gravity sampling interval time. According to this configuration, the division value obtained by dividing the rotation period of one axle by the gravity sampling interval time corresponds to the number of times of sampling per one period of gravity sampling. Therefore, since acceleration / deceleration is determined from a change in the number of gravity samplings per cycle, it is advantageous for determining acceleration / deceleration more correctly.

  In the tire position registration system, it is preferable that the period calculation unit calculates the one rotation period of the axle in a time zone in which the specific position is monitored in the tire valve. According to this configuration, the one axle rotation cycle on the receiver side and the gravity sampling cycle on the tire valve side are associated with each other, which is advantageous in determining the acceleration more correctly.

  In the tire position registration system, the acceleration / deceleration determination unit continuously performs the acceleration / deceleration determination in time series by repeating the process of comparing the determination parameters before and after each time a new determination parameter is calculated. It is preferable to carry out. According to this configuration, it is possible to continuously monitor acceleration / deceleration monitoring, which is advantageous in determining acceleration more correctly.

  In the tire position registration system, when it is determined that acceleration / deceleration is being performed, the position determination unit lightens the weight of the received radio wave or discards the radio wave, and when it is determined that acceleration / deceleration is not being performed, the received radio wave It is preferable to adopt or increase the weight of the radio wave. According to this configuration, the weight of the tire valve radio wave is weighted according to the acceleration / deceleration dependency of the vehicle, so that even if the vehicle is in a state of acceleration / deceleration, the tire position can be determined more correctly. Is advantageous.

  In the tire position registration system, the tire valve can notify the receiver of information on the number of gravity samplings per cycle of gravity sampling calculated in the tire valve in communication with the receiver. If the determination unit can confirm the validity of the gravity sampling based on the rotation period of the axle, the gravity sampling interval time, and the number of gravity samplings, the received radio wave is normally transmitted even if the gravity sampling number does not take the target value. It is preferable to handle as street. By the way, the number of times of gravity sampling per one period of gravity sampling is easily influenced by, for example, acceleration / deceleration of the vehicle or traveling on a rough road, so that the number of times of gravity sampling may not become a predetermined target value. In this case, if the data is discarded simply because the number of times of gravity sampling does not reach the target value, sufficient data necessary for determining the tire position cannot be easily collected, and it takes time to determine the tire position. Therefore, the information on the number of gravity samplings is transmitted from the tire valve to the receiver, and this is compared with the highly reliable axle one rotation cycle. If they match, the number of gravity samplings is assumed to be the target value. Even if not, it is taken in as data used for determination of the tire position. As a result, data necessary for the determination of the tire position can be collected at an early stage, and as a result, it is advantageous to accelerate the determination of the tire position.

  In the tire position registration system, the position determination unit calculates a distribution of axle rotation information of each axle for each valve ID by taking statistics of the axle rotation information for each valve ID, and based on this distribution. It is preferable to determine the tire position by confirming the synchronization of the valve ID and the axle. According to this configuration, since the tire position is determined by handling each piece of axle rotation information as individual data, a large amount of data necessary for determining the tire position can be collected in a short time. This is advantageous in that the time required for tire position determination can be shortened. Therefore, it is possible to determine the tire position more correctly in a short time.

  According to the present invention, the tire position can be determined more correctly.

The lineblock diagram of the tire position registration system of a 1st embodiment. Explanatory drawing which shows the component of the gravity component force detected with a tire valve. (A), (b) is a communication sequence diagram of a tire valve. Explanatory drawing of sampling logic of gravity force. The distribution map of axle rotation information (pulse count value) of each wheel in a certain ID. Waveform diagram of gravitational force during constant speed running. Waveform diagram of gravitational force during acceleration running. A distribution table of axle rotation information (pulse count value) created for each ID. Deviation mean and standard deviation formulas. The communication sequence diagram of the tire valve of 2nd Embodiment.

(First embodiment)
Hereinafter, 1st Embodiment of a tire position registration system is described according to FIGS.
As shown in FIG. 1, the vehicle 1 includes a tire pressure monitoring system (TPMS) 3 that monitors the air pressure and the like of each tire 2 (2 a to 2 d). The tire pressure monitoring system 3 includes tire valves 4 (4a to 4d) attached to the tires 2a to 2d. The tire valve 4 is a tire valve sensor in which a tire plug is provided with a sensor and a communication function. The tire pressure monitoring system 3 transmits a radio wave (valve radio wave) Sva associated with at least the pressure data and ID of the tire 2 from the tire valves 4 a to 4 d to the vehicle body 5. Monitor air pressure.

  The tire valve 4 detects a controller 6 that controls the operation of the tire valve 4, a pressure detection unit 7 that detects tire air pressure, a temperature detection unit 8 that detects the temperature of the tire 2, and gravity that occurs in the tire valve 4. And a transmission antenna 10 that enables radio wave transmission from the tire valve 4. A valve ID is written and stored in the memory 11 of the controller 6 as a unique ID of each tire valve 4. The pressure detector 7 is preferably a pressure sensor, for example. The temperature detector 8 is preferably a temperature sensor, for example. The gravity detector 9 is preferably an acceleration sensor (G sensor), for example. The transmission antenna 10 is preferably capable of transmitting a radio wave of, for example, a UHF (Ultra High Frequency) band.

  The vehicle body 5 includes a receiver (hereinafter referred to as a TPMS receiver 12) that monitors the air pressure of the tires 2a to 2d by receiving the radio waves Sva transmitted from the tire valves 4a to 4d. The TPMS receiver 12 includes a tire pressure monitoring ECU (Electronic Control Unit) 13 that controls the operation of the TPMS receiver 12 and a receiving antenna 14 that enables radio waves to be received by the TPMS receiver 12. In the memory 15 of the tire pressure monitoring ECU 13, the valve IDs acquired from the tire valves 4a to 4d are written and stored. The TPMS receiver 12 is connected to a display unit 16 that displays the monitoring result of the air pressure. It is preferable that the display part 16 is installed in the instrument panel in a vehicle, for example.

  When the reception antenna 14 receives the radio wave Sva transmitted from the tire valves 4a to 4d at a certain timing, the TPMS receiver 12 collates the valve ID in the radio wave Sva, and if the valve ID collation is established, Check the pressure data (air pressure data). If the air pressure is equal to or lower than the low pressure threshold, the TPMS receiver 12 displays on the display unit 16 that the tire air pressure is low. The TPMS receiver 12 performs the tire pressure determination for each received radio wave Sva, and monitors the tire pressures of the tires 2a to 2d.

  The tire pressure monitoring system 3 automatically associates the valve IDs of the tire valves 4a to 4d with the IDs of the tires 2a to 2d attached to the front, rear, left and right of the vehicle body 5 to the TPMS receiver 12 automatically. A tire valve ID registration function to register, a so-called auto location function (tire position registration system 17) is provided. The tire position registration system 17 performs a plurality of operations to acquire the rotation position (rotation amount) of each axle 18 (18a to 18d) of the four wheels when the tire valves 4a to 4d take a specific position in the tire rotation direction. By ascertaining which valve ID is synchronized with which rotational position (rotation amount) of each axle 18a-18d, the valve ID is associated with the axles 18a-18d, and the tires 2a-2d The position of is determined.

  FIG. 2 illustrates a gravity component detected by the gravity detection unit 9. It is preferable that the gravity detection unit 9 detects the gravity component Gr in the axle direction (tire radial direction) with respect to the gravity G as the gravity applied to the tire valve 4. For example, if the centrifugal force is not taken into account, the gravitational component force Gr takes “−1G” or “+ 1G” when it is located at the peak (position “12 o'clock” or “6 o'clock”) in the tire rotation direction. . The detected gravity component Gr may be a tangential component force in the tire rotation direction.

  FIG. 3A illustrates a radio wave transmission sequence of the tire valve 4. It is preferable that the tire valve 4 alternately takes a first time zone T1 of a short time during which radio waves can be transmitted and a second time zone T2 of a long time during which radio waves are not transmitted. The first time period T1 is preferably “1 second”, for example. The second time period T2 is preferably “30 seconds”, for example. Thus, the tire valve 4 repeats the operation of transmitting radio waves during a limited time of 1 second with an interval of about 30 seconds.

  As shown in FIG. 1, the tire valve 4 includes a specific position detection unit 19 that can detect that the tire valve 4 is positioned at a specific position in the tire rotation direction, and a radio wave that indicates that the tire 2 is positioned at a specific position ( As an example, it is preferable to include the transmission processing unit 20 that transmits the specific position information radio wave Spi) from the tire valve 4 including at least the valve ID. The specific position detection unit 19 and the transmission processing unit 20 are preferably provided in the controller 6, for example. The specific position is preferably, for example, a peak position in the tire rotation direction (an example is a position of “12:00”). The detection of the peak position is preferably executed a plurality of times continuously before radio wave transmission. The transmission of the specific position information radio wave Spi may be executed a plurality of times, for example, according to the number of times the peak position is detected. The specific position information radio wave Spi is transmitted during a first time period T1 that the tire valve 4 periodically takes.

  The tire valve 4 preferably includes an information holding unit 21 that holds one or more specific position information Dgr indicating when the tire valve 4 took a specific position in the second time zone T2. This is because, for example, when the vehicle 1 travels at a low speed and the tire 2 rotates slowly, there may occur a situation in which the peak cannot be detected a predetermined number of times during the short first time period T1, so that the peak occurs in the second time period T2 where radio waves are not transmitted This is because the position is detected in advance. Also, for example, if the radio wave is transmitted only at a certain tire angle, when this point becomes null, it will continue to be affected by the null, but the transmission of this example In this case, since radio waves are transmitted at an arbitrary tire angle, there is no fixed influence of null. That is, there is an advantage of preventing a risk that the reception rate of the TPMS receiver 12 is remarkably lowered in the determination of the tire position.

  The specific position information Dgr is preferably peak information that can determine when the tire valve 4 has taken a peak. The specific position information Dgr is constructed from the number of gravity sampling points Nx indicating how many times the measurement has been performed since the start of gravity sampling (actual gravity sampling), the gravity sampling interval time Tb that is the execution interval of gravity sampling, and the like. It is preferable.

  As shown in FIG. 3B, it is preferable that the information holding unit 21 detects a peak of a predetermined number of times (for example, 8 times) in a predetermined time zone that goes back from the start point T1a of the first time zone T1. . The transmission processing unit 20 sequentially transmits one or more specific position information Dgr held so far together with the valve ID in the number of the specific position information Dgr at the first time period T1 in which radio wave transmission is possible. Is preferred. That is, the transmission processing unit 20 causes the tire valve 4 to transmit radio waves including the specific position information Dgr and ID (for example, the specific position information radio wave Spi) in order from the tire valve 4 by the number of the specific position information Dgr held. The transmission processing unit 20 may continuously transmit the specific position information radio waves Spi for one packet so as to finish transmission during the first time period T1. The specific position information radio wave Spi has a time length of about 10 ms, for example, and may be repeatedly transmitted at intervals of about 100 ms.

  As shown in FIG. 1, the tire position registration system 17 is based on the axle rotation information (pulse measurement value) Dc obtained from the axle rotation detection unit 22 that can detect the rotation of the axle 18, and the cycle (hereinafter referred to as the cycle per axle rotation). , A cycle calculating unit 23 for calculating one axle rotation cycle Sn (where n = 1, 2,...) Is provided. The period calculation unit 23 is preferably provided, for example, in the tire air pressure monitoring ECU 13. The cycle calculating unit 23 may calculate the one axle rotation cycle Sn for one specific axle 18, or based on the detection signals of the axle rotation detecting units 22a to 22d, the axle one rotation cycle Sn for each axle 18a to 18d. May be calculated.

  The axle rotation detection units 22a to 22d are preferably ABS (Antilock Brake System) sensors provided on the axles 18a to 18d. In this case, the axle rotation information Dc is preferably the number of pulses detected by, for example, an ABS sensor, that is, a pulse count value. The axle rotation detectors 22a to 22d detect, for example, a plurality of (for example, 48) teeth provided on the axles 18a to 18d by the sensing unit on the vehicle body 5 side, thereby generating a rectangular wave-shaped pulse signal Spl as a TPMS. Output to the receiver 12. The axle rotation detection unit 22 detects 96 pulses (count value: 0 to 95) per tire rotation if both the rising edge and falling edge of the input pulse signal Spl are detected.

  The tire position registration system 17 is a parameter calculation unit 24 that can calculate a determination parameter K for each axle rotation period Sn, based on a variable gravity sampling interval time Tb, which is a gravity detection execution interval, and the axle rotation period Sn. Is provided. The parameter calculation unit 24 is preferably provided, for example, in the tire pressure monitoring ECU 13. The determination parameter K is preferably “Sn / Tb” obtained by dividing the one axle rotation period Sn by the gravity sampling interval time Tb.

  The tire position registration system 17 includes an acceleration / deceleration determination unit 25 that determines acceleration / deceleration of the vehicle 1 based on a change in the determination parameter “Sn / Tb”. The acceleration / deceleration determination unit 25 is preferably provided, for example, in the tire air pressure monitoring ECU 13. When the acceleration / deceleration determination unit 25 confirms that the determination parameter “Sn / Tb” decreases before and after, the vehicle 1 determines that “acceleration” and the determination parameter “Sn / Tb” increases before and after. Then, it is determined that the vehicle 1 is “decelerating”. The acceleration / deceleration determination unit 25 repeats the process of comparing the determination parameters “Sn / Tb” before and after each time a new determination parameter “Sn / Tb” is calculated, thereby determining the acceleration / deceleration determination in time series. It is good to execute continuously. The acceleration / deceleration determination unit 25 may be any unit that determines at least one of acceleration and deceleration.

  The tire position registration system 17 includes a position determination unit 26 that associates each valve ID with a tire position and registers it in the TPMS receiver 12. The position determination unit 26 causes each tire valve 4 to transmit a radio wave (for example, the specific position information radio wave Spi) that indicates that the tire valve 4 is located at a specific position (an example is a peak position) in the tire rotation direction, and this is transmitted to the TPMS. A plurality of axle rotation information Dc of each axle 18a to 18d when each tire valve 4 takes a specific position is received for each specific position. The position determination unit 26 determines the tire position by associating the valve ID and the axles 18a to 18d with each other by confirming which ID is synchronized with which of the axle rotation information Dc. The position determination unit 26 determines the tire position based on the determination result of the acceleration / deceleration determination unit 25.

  The position determination unit 26 treats a plurality (eight in this example) of specific position information radio waves Spi received as one packet as individual data. Each time the position determination unit 26 receives the specific position information radio wave Spi, it reads out the axle rotation information Dc of each axle rotation detection unit 22a to 22d, takes these distributions, and confirms the distributions to thereby determine the tires 2a to 2a. The position of 2d is determined. When peak detection is performed in advance in the second time period T2, the position determination unit 26 uses the axle rotation information Dc stored in the memory 15, and the axle rotation for each specific position from the received specific position information Dgr. It is preferable to reversely calculate the information Dc and determine the tire position from the reversely calculated value.

Next, operation | movement of the tire position registration system 17 is demonstrated using FIGS.
As shown in FIG. 4, when the tire valve 4 is in the second time zone T2 in which radio waves are not transmitted, the gravitational component force Gr is read a predetermined time before the peak detection is started, and is read in order to confirm the gravity waveform. A gravity sampling interval time Ta having a longer time corresponding to the gravity component Gr is set. Then, the tire valve 4 starts pre-gravity sampling for detecting the gravitational force Gr at the gravity sampling interval time Ta.

  In the pre-gravity sampling, the tire valve 4 first monitors where the peak of the gravity component Gr is in the gravity sampling performed at the gravity sampling interval time Ta. For the peak, for example, it is preferable to determine the second “decrease” point when the gravity component Gr changes from decrease → decrease → increase → increase as the peak position. When the tire valve 4 detects the peak of the gravity component force Gr, the tire valve 4 again monitors the peak of the gravity component force Gr in order to measure one period of the pre-gravity sampling. When the tire valve 4 detects the peak of the gravity component Gr again, the tire valve 4 calculates the pre-gravity sampling period based on the time between the previous peak and the subsequent peak. Then, the tire valve 4 sets “Tb” corresponding to the period of the pre-gravity sampling as a gravity sampling interval time used in actual gravity sampling. That is, since the number of times of gravity sampling per rotation of the tire is determined by a specified value (for example, 12 times), the optimum gravity sampling interval time Tb is set so that the number of times of gravity sampling takes the specified value during actual gravity sampling. The

  The tire valve 4 executes actual gravity sampling at the gravity sampling interval time Tb. That is, the tire valve 4 repeatedly detects the gravitational force Gr at the gravity sampling interval time Tb, and detects a plurality of peak positions necessary for determining the tire position. In the case of this example, one period of actual gravity sampling is “Tr” having a time width including a specified number (for example, 12 times) of the gravity sampling interval time Tb.

  When the information holding unit 21 detects the peak position in the gravity sampling repeatedly executed at the gravity sampling interval time Tb, the information holding unit 21 stores the specific position information Dgr in the memory 11. Thereafter, the information holding unit 21 holds the specific position information Dgr in the memory 11 every time a peak is detected.

  As shown in FIG. 3, when the transmission processing unit 20 reaches the first time zone T1 in which radio wave transmission is possible, the specific position information Dgr held in the memory 11 is equal to the number of specific position information Dgr. The specific position information radio wave Spi is transmitted in order from the transmission antenna 10. The specific position information radio wave Spi is a signal including at least a valve ID and specific position information Dgr. More specifically, the specific position information radio wave Spi may be a signal including each information of the valve ID, the number of gravity sampling points Nx, and the gravity sampling interval time Tb. The number of gravity sampling points Nx corresponds to the number (total number) of gravity samplings after the gravity sampling is started at the gravity sampling interval time Tb. The specific position information radio wave Spi may be continuously transmitted at a short interval of, for example, 100 ms so that it can be transmitted during the first time period T1.

  As illustrated in FIG. 5, the position determination unit 26 acquires the axle rotation information Dc of each axle rotation detection unit 22a to 22d every time the specific position information radio wave Spi is received. In the case of this example, the position determination unit 26 reversely calculates the axle rotation information Dc stored in the memory 15 based on the received specific position information Dgr, and calculates a reverse calculation value for each specific position information Dgr. And the position determination part 26 takes the statistics of these back calculation values, and adds each statistic every time it receives each specific position information radio wave Spi of a packet unit, and determines a tire position. That is, as shown in the figure, when the portion is calculated at the first packet and the tire position is not fixed at the first packet, the tire position is determined by adding the distribution of the second packet to the distribution of the first packet. The The same processing is repeated after the third packet, and the distribution is updated, and the tire position is determined from this distribution.

  FIG. 6 illustrates a change in the waveform of the gravity component Gr when the vehicle speed is constant. The TPMS receiver 12 determines whether or not the vehicle 1 is accelerating / decelerating when receiving a plurality of specific position information radio waves Spi transmitted from the tire valve 4. At this time, first, the period calculation unit 23 calculates the axle one rotation period S1 for the first peak based on the axle rotation information Dc by calculating backward the axle rotation information Dc stored in the memory 15. Further, the parameter calculation unit 24 calculates the determination parameter “S1 / Tb” for the first peak by dividing the one axle rotation cycle S1 by the gravity sampling interval time Tb in the specific position information radio wave Spi. Further, in the same way, the cycle calculation unit 23 calculates the axle one rotation cycle S2 for the second peak, and the parameter calculation unit 24 calculates the determination parameter “S2 / Tb” for the second peak.

  The acceleration / deceleration determination unit 25 determines the acceleration / deceleration of the vehicle 1 by comparing the determination parameter “S1 / Tb” for the first peak with the determination parameter “S2 / Tb” for the second peak. If the difference between “S1 / Tb” and “S2 / Tb” is less than a predetermined value, the acceleration / deceleration determination unit 25 determines that the vehicle 1 is not accelerating / decelerating, and “S1 / Tb” and “S2 / Tb” are determined. If the difference from “Tb” is equal to or greater than a predetermined value, it is determined that the vehicle 1 is accelerating / decelerating.

  Subsequently, the cycle calculating unit 23 calculates an axle one rotation cycle S3 for the third peak through a process of calculating back the axle rotation information Dc stored in the memory 15. Further, the parameter calculation unit 24 calculates the determination parameter “S3 / Tb” for the third peak by dividing the one axle rotation cycle S3 by the gravity sampling interval time Tb. The acceleration / deceleration determination unit 25 determines acceleration / deceleration of the vehicle 1 by comparing “S2 / Tb” with “S3 / Tb”. Thereafter, the acceleration / deceleration determination unit 25 confirms whether acceleration / deceleration has occurred in the vehicle 1 by repeating the same processing.

  In the case of the example in FIG. 6, the gravitational component force Gr has the same amplitude and repeats a certain period. That is, since the axle rotation period Sn is constant in time series and the gravity sampling interval time Tb is also fixed, the determination parameter “Sn / Tb” matches or approximates. The acceleration / deceleration determination unit 25 determines that the vehicle speed is “constant” during the time period if the determination parameter “Sn / Tb” is constant or approximate before and after the time series. The acceleration / deceleration determination unit 25 performs the same determination every time a new determination parameter “Sn / Tb” is calculated, and determines whether or not the vehicle speed is constant.

  When it is determined that the vehicle speed is constant (not determined as accelerating / decelerating), the position determination unit 26 may adopt the received specific position information radio wave Spi or increase the weight. In order to increase the weighting, for example, it may be realized by increasing the weighting coefficient. When the vehicle speed is constant and low, it can be said that the accuracy of the received specific position information radio wave Spi is high, so that the weighting may be set heavier.

  FIG. 7 illustrates a change in the waveform of the gravitational component force Gr when the vehicle 1 is accelerating. The waveform of the gravitational force Gr takes a waveform that gradually rises to the right with the passage of time (speed increase). That is, although the gravity sampling interval time Tb is always constant, the determination parameter “Sn / Tb” gradually decreases because the axle rotation period Sn decreases with acceleration. The acceleration / deceleration determination unit 25 determines that the vehicle 1 is “accelerating” during the time period if a predetermined amount of difference occurs in the determination parameter “Sn / Tb” before and after the time series. On the other hand, if the difference is within the predetermined amount, it is determined that the vehicle 1 is “not accelerating” during the time period. The acceleration / deceleration determination unit 25 performs the same determination every time a new determination parameter “Sn / Tb” is calculated, and determines whether or not the vehicle 1 is accelerating.

  The position determination unit 26 may reduce or discard the weighting of the received specific position information radio wave Spi when it is determined that the acceleration value is large. In order to reduce the weighting, for example, it may be realized by reducing the weighting coefficient. When it is determined that the acceleration value is small, the position determination unit 26 may handle the received specific position information radio wave Spi as usual. In this case, the specific position information radio wave Spi may be simply taken in, or the weight may be increased.

  This determination method can also be applied when the vehicle 1 decelerates. That is, at the time of deceleration, the determination parameter “Sn / Tb” gradually changes to a large value, so that the difference between the determination parameter “Sn / Tb” before and after the time series becomes larger than a predetermined amount. Therefore, the acceleration / deceleration determination unit 25 can determine that the vehicle 1 is decelerating with this difference.

  When the determination parameter “Sn / Tb” matches or approximates the target value (for example, 12 times), the position determination unit 26 treats the received specific position information radio wave Spi as accurate data, and conversely sets the target value and the predetermined value. When there is a difference, the received specific position information radio wave Spi may be handled as inaccurate data. The target value is an ideal number of gravity samplings per one period of gravity sampling. Handling with high accuracy data may be, for example, handling of acquiring data or increasing weighting. The handling as data with poor accuracy may be, for example, handling such as discarding the data or reducing the weight of the data to be captured.

  As shown in FIG. 8, a specific example of tire position determination is illustrated. The position determination unit 26 creates a distribution table 27 as shown in FIG. The position determination unit 26 performs “absolute evaluation” for determining the correctness of the distribution independently in each axle rotation information Dc, and “relative evaluation” for determining the correctness of the distribution between the other axle rotation information Dc. It is preferable to determine the tire position based on these evaluation results. Relative evaluation is an index for determining whether the own wheel is sufficiently synchronized with the other wheel by comparing the own wheel with the other wheel. In this example, “average of deviation” and “standard deviation” are given as examples of distribution. The average deviation and standard deviation are smaller as the determination result is better.

  As shown in FIG. 9, the average deviation is the same when the pulse count value is “x”, the total number of collected pulse count values is “n”, and the average of the collected pulse count values is “x ′”. It is calculated from the equation (α) in the figure. The standard deviation is calculated from the equation (β) in the figure. Hereinafter, “average deviation” and “standard deviation” are collectively referred to as “bias value”. The absolute evaluation is an evaluation for determining whether or not the bias value falls below a threshold value. Relative evaluation calculates the difference between the deviation value of the own wheel and the deviation value of the other wheel, and whether or not this difference is equal to or greater than the threshold, that is, the deviation value of the absolute evaluation of the own wheel is sufficiently larger than that of the other wheel It is evaluation which determines whether it is small. The position determination unit 26 determines that the axle 18 and the tire 2 are synchronized and determines the combination if the bias value is equal to or smaller than the threshold value in the absolute evaluation and the difference between the bias values is equal to or larger than the threshold value in the relative evaluation. .

  In the case of the example of FIG. 8, the pulse count values of the left front axle 18b in ID1 are collected in the vicinity of “20”, so the bias value of the left front axle 18b in ID1 is within the threshold value, and the left front axle 18b satisfies the absolute evaluation in ID1. To do. On the other hand, in ID1, since each pulse count value of the right front axle 18a, the right rear axle 18c, and the left rear axle 18d takes a value that does not converge to one value, these bias values take bad values. For this reason, the difference between the deviation value of the left front axle 18b in ID1 and that of the other axle is equal to or greater than the threshold value, so the relative evaluation is also satisfied. Therefore, since it can be confirmed that ID1 is synchronized with the left front axle 18b, these are linked and it is determined that ID1 is the left front tire 2b. Similarly, the tire positions are also determined in ID2 to ID4.

  If the position determination unit 26 cannot determine the positions of all four wheels in one determination, the position determination unit 26 determines the positions of the remaining wheels by the same process. Then, the same processing is repeated until the positions are determined for all four wheels. When the position determination for all four wheels is completed, the position determination unit 26 writes the determination result in the memory 15 and updates the tire position. The tire position determination process may be executed each time the ignition switch of the vehicle 1 is turned on, for example.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) “Sn / Tb”, which is a determination parameter K between each peak-peak, based on one axle rotation period Sn calculated by the TPMS receiver 12 and the gravity sampling interval time Tb set by the tire valve 4 ”Is calculated, and the acceleration / deceleration of the vehicle 1 is determined by checking the time-series changes of these determination parameters“ Sn / Tb ”. Based on the acceleration / deceleration determination result, the tire position is determined. Therefore, when determining the tire position and registering it in the TPMS receiver 12, it is possible to determine the position according to the acceleration / deceleration of the vehicle 1, so that even if the vehicle 1 is accelerating / decelerating, the tire position is more correctly determined. can do.

  (2) The determination parameter K is “Sn / Tb”, which is a value obtained by dividing the axle rotation period Sn by the gravity sampling interval time Tb. This corresponds to the number of times of sampling per cycle of gravity sampling. Therefore, since acceleration / deceleration is determined from a change in the number of gravity samplings per cycle, it is advantageous for determining acceleration / deceleration more correctly.

  (3) The cycle calculation unit 23 calculates an axle one-rotation cycle Sn in a time zone in which the specific position of the tire valve 4 is monitored (this example is an actual gravity sampling time zone). Therefore, the axle 1 rotation cycle Sn on the TPMS receiver 12 side and the gravity sampling cycle Tr on the tire valve 4 side are associated with each other, which is advantageous for determining the acceleration more correctly.

  (4) The acceleration / deceleration determination unit 25 repeats the process of comparing the previous and subsequent determination parameters “Sn / Tb” each time a new determination parameter “Sn / Tb” is calculated, thereby determining acceleration / deceleration. Run continuously in series. That is, “S1 / Tb” and “S2 / Tb” are compared, followed by “S2 / Tb” and “S3 / Tb”, and the same process is repeated each time a new Sn is acquired. Determine deceleration. Therefore, it is possible to continuously monitor the acceleration / deceleration monitoring, which is advantageous for determining the acceleration more correctly.

  (5) When it is determined that acceleration is being performed, the weight of the received radio wave Sva is decreased, or the radio wave Sva is discarded, and when it is not determined that acceleration is being performed, the received radio wave Sva is adopted or the radio wave Sva is increased in weight. To do. Therefore, since the weighting according to the acceleration / deceleration dependency of the radio wave Sva is performed, even if the vehicle 1 is in a state of acceleration / deceleration, it is advantageous to determine the tire position more correctly.

  (6) The tire valve 4 transmits to the TPMS receiver 12 a radio wave Sva that can determine that the tire valve 4 is positioned at the peak in the tire rotation direction. The TPMS receiver 12 acquires the axle rotation information Dc of the axles 18a to 18d when the tire valve 4 takes the peak position, and performs this operation for each of ID1 to ID4 and for each acquired peak. A data group of axle rotation information Dc necessary for position determination is collected. The distribution of the axle rotation information Dc is calculated for each of ID1 to ID4 by taking statistics of the axle rotation information Dc for each of the axles 18a to 18d for each of ID1 to ID4, and the tire position is determined from this distribution. As described above, since the tire position is determined by handling each piece of the axle rotation information Dc as individual data, a large amount of data necessary for the tire position determination can be collected in a short time. This is advantageous in that the time required for tire position determination can be shortened. Therefore, the tire position can be determined more correctly in a short time.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG. The second embodiment is an example in which the handling of the received radio wave (specific position information radio wave Spi) of the first embodiment is changed. Therefore, the same part as 1st Embodiment attaches | subjects the same code | symbol, description is abbreviate | omitted, and only a different part is explained in full detail.

  As shown in FIG. 10, the tire valve 4 is preferably capable of notifying the TPMS receiver 12 of the information on the number of gravity samplings Np per cycle calculated in the tire valve 4 in communication with the TPMS receiver 12. . The number of gravity samplings Np is the total number of gravity samplings performed between the previous and next peaks. In sampling the gravity component Gr, the tire valve 4 sequentially measures the number of gravity samplings Np required for one cycle of gravity sampling each time a peak is detected. The tire valve 4 may notify the TPMS receiver 12 of the gravity sampling frequency Np by transmitting information on the gravity sampling frequency Np in the specific position information radio wave Spi.

  The position determination unit 26 determines the appropriateness of the accuracy of gravity sampling based on the number of gravity samplings Np acquired from the tire valve 4, the one axle rotation cycle Sn, and the gravity sampling interval time Tb. More specifically, the position determination unit 26 compares the above-described determination parameter “Sn / Tb” with the number of gravity samplings Np acquired from the tire valve 4 to determine the validity of the accuracy of gravity sampling. The position determination unit 26 compares the determination parameter “Sn / Tb” with the number of gravity sampling times Np for each received specific position information radio wave Spi. In other words, it is preferable that the validity determination is performed every time the determination parameter “Sn / Tb” is obtained, for example.

  The position determination unit 26 calculates the difference between the determination parameter “Sn / Tb” and the number of gravity samplings Np, and if the difference is within a predetermined value, the received position information radio wave Spi is normally transmitted. Handle and get as correct data. That is, not only when the gravity sampling number Np matches the target value (for example, 12 times), but even if the gravity sampling number Np deviates from the target value, the difference between “Sn / Tb” and Np is a predetermined value. If it falls within the range, the specific position information radio wave Spi received at this time is acquired as correct data. When acquired as correct data, the received specific position information radio wave Spi may be weighted.

  By the way, when the vehicle is in a special traveling state such as traveling on a rough road, for example, the determination parameter “Sn / Tb” may not necessarily match the target value. However, if the determination parameter “Sn / Tb” takes a value close to the number of gravity samplings Np actually measured by the tire valve 4, it can be said that these are likely to be a set. Therefore, in this example, if it can be confirmed that the difference between the determination parameter “Sn / Tb” and the number of gravity samplings Np falls within a predetermined value, the data is acquired as correct data. This makes it possible to determine the tire position efficiently without wasting information on the peak position detected by the tire valve 4.

  In addition, the validity judgment of the accuracy of gravity sampling can be changed to another method. For example, the axle one rotation cycle Sn is calculated by the same method as described above, and the axle one rotation cycle Sn is divided by the gravity sampling number Np acquired from the tire valve 4 to calculate the sampling time information “Sn / Np”. . Then, the sampling time information “Sn / Tb” is compared with the gravity sampling interval time Tb actually measured by the tire valve 4, and if this difference is within a predetermined value, it is determined that the accuracy of the gravity sampling is good, and the reception is performed. The specified position information radio wave Spi may be handled as usual.

According to the configuration of the present embodiment, the following effects can be obtained in addition to (1) to (6) described in the first embodiment.
(7) The information of the number of gravity samplings Np is transmitted from the tire valve 4 to the TPMS receiver 12, and this is compared with the highly reliable axle rotation period Sn of the data. Even if the number of times of sampling Np is not the target value, the received radio wave Sva is captured as data used for determining the tire position. As a result, data necessary for the determination of the tire position can be collected at an early stage, and as a result, it is advantageous to accelerate the determination of the tire position.

Note that the embodiment is not limited to the configuration described so far, and may be modified as follows.
-In each embodiment, the tire valve 4 performs transmission of a specific position information radio wave Spi of one packet for a predetermined number of times, and then does not perform gravity monitoring, and simply transmits a tire pressure signal associated with air pressure data and an ID. A sequence may be taken.

In each embodiment, the specific position information Dgr collected during the second time zone T2 may be transmitted all at once at the time of the first radio wave transmission when the first time zone T1 arrives.
-In each embodiment, various information, such as the time which detected the peak position, the time which traced back from the starting point T1a of 1st time slot | zone T1, can be employ | adopted for specific position information Dgr.

In each embodiment, the specific position is not limited to the peak position, and may be a specific position taken by the tire valve 4 in the tire rotation direction.
In each embodiment, the axle rotation detection unit 22 may output a pulse count value detected during a certain time interval to the TPMS receiver 12 as count data.

In each embodiment, the axle rotation detection unit 22 may wirelessly transmit a detection signal to the TPMS receiver 12.
In each embodiment, the axle rotation information Dc is not limited to the pulse count value, and can be changed to another parameter as long as it is similar to the rotation position of the axle 18.

In each embodiment, the weighting method can be changed to various modes.
In each embodiment, the tire valve 4 is not limited to detecting the peak in advance in the second time zone T2 in which radio wave transmission is not performed, but in the first time zone T1 in which radio wave transmission is possible. The specific position information radio wave Spi may be transmitted at the timing.

In each embodiment, the tire valve 4 may periodically transmit the specific position information Dgr.
In each embodiment, when the specific position information radio wave Spi is transmitted a plurality of times, the gravity sampling interval time Tb information may be transmitted only once.

  In the second embodiment, the TPMS receiver 12 is not limited to obtaining information on the number of gravity sampling times Np from the tire valve 4, and for example, calculates the difference in the number of gravity sampling points Nx before and after in time series, and gravity sampling The number of times Np may be calculated.

  In each embodiment, the comparison of the determination parameter “Sn / Tb” is not limited to being performed continuously in time series. For example, a predetermined number may be skipped so as to compare “S1 / Tb” with “S3 / Tb”. Further, “S1 / Tb” and “S2 / Tb” may be compared, and “S3 / Tb” and “S4 / Tb” may be compared next.

  In each embodiment, the determination parameter K is not limited to a value obtained by dividing the axle rotation period Sn by the gravity sampling interval time Tb, and a value calculated by another calculation method may be adopted.

  In each embodiment, the tire position determination method is not limited to the method of determining the position by taking the distribution of the axle rotation information Dc of each axle 18a to 18d for each ID as described in the embodiment. For example, the tire position may be determined by averaging the axle rotation information Dc of each axle 18a to 18d for each ID and confirming which of the average values the ID is synchronized with. Thus, the tire position determination method can be appropriately changed to various modes.

  In each embodiment, the distribution is not limited to variation, average deviation, and standard deviation, and can be changed to other parameters as long as the synchronization between the valve ID and the axle 18 can be determined.

  In each embodiment, the radio wave for auto location is not limited to being classified into Spi with respect to Sva. That is, the tire pressure notification radio wave Sva and the specific position information radio wave Spi can be handled as the same radio wave.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 (2a-2d) ... Tire, 4 (4a-4d) ... Tire valve, 5 ... Vehicle body, 12 ... Receiver (TPMS receiver), 17 ... Tire position registration system, 18 (18a-18d) ... Axle, 22 (22a-22d) ... Axle rotation detector, 23 ... Cycle calculator, 24 ... Parameter calculator, 25 ... Acceleration / deceleration determiner, 26 ... Position determiner, Sva ... Radio wave, Spi ... Tire valve radio wave Specific position information radio waves, Sn (n = 1, 2,...) ... axle one rotation period, Tb ... gravity sampling interval time, K (Sn / Tb) ... determination parameter, Dc ... axle rotation information (pulse count value) ), Np: number of gravity samplings.

Claims (7)

Necessary for transmitting a radio wave including tire pressure data from the tire valve of each tire and receiving the radio wave with a receiver of the vehicle body and monitoring the air pressure of each tire, and the tire valve ID corresponds to the tire position In addition, in the tire position registration system for registering in the receiver,
Based on the axle rotation information obtained from the axle rotation detection unit capable of detecting the rotation of the axle, a cycle per one rotation of the axle can be calculated, and a cycle calculating unit capable of executing this over a plurality of rotations;
A parameter calculation unit that calculates a determination parameter based on a variable gravity sampling interval time that is an interval of gravity detection and an axle rotation period, and obtains the determination parameter for each rotation period of the axle;
An acceleration / deceleration determination unit that determines acceleration / deceleration of the vehicle from a change in the determination parameter;
Axle of each axle when each tire valve takes the specific position by transmitting a radio wave from each tire valve that is recognized that the tire valve is located at a specific position in the tire rotation direction and receiving the radio wave by the receiver Position determination for determining tire position by associating the valve ID with the axle by obtaining a plurality of rotation information for each specific position and confirming which axle rotation information the valve ID is synchronized with With
The tire position registration system, wherein the position determination unit determines a tire position based on a determination result of the acceleration / deceleration determination unit. 2. The tire position registration system according to claim 1, wherein the parameter calculation unit calculates the determination parameter by dividing the one rotation period of the axle by the gravity sampling interval time. 3. The tire position registration system according to claim 1, wherein the cycle calculation unit calculates the one rotation cycle of the axle in a time zone in which the specific position is monitored in the tire valve. The acceleration / deceleration determination unit continuously performs the acceleration / deceleration determination in time series by repeating the process of comparing the determination parameters before and after each time a new determination parameter is calculated. The tire position registration system according to any one of claims 1 to 3. When it is determined that acceleration / deceleration is being performed, the position determination unit lightens the weight of the received radio wave, or discards the radio wave, and when it is not determined that acceleration / deceleration is being performed, uses the received radio wave, or The tire position registration system according to any one of claims 1 to 4, wherein weighting is increased. The tire valve can notify the receiver of information on the number of gravity samplings per cycle of gravity sampling calculated in the tire valve in communication with the receiver,
If the position determination unit can confirm the validity of the gravity sampling based on the one axle rotation cycle, the gravity sampling interval time, and the gravity sampling frequency, the received radio wave can be received even if the gravity sampling frequency does not take the target value. The tire position registration system according to any one of claims 1 to 5, wherein the tire position is handled as usual. The position determination unit calculates a distribution of axle rotation information of each axle for each valve ID by taking statistics of the axle rotation information for each valve ID, and synchronizes the valve ID and the axle based on this distribution. The tire position registration system according to any one of claims 1 to 6, wherein the tire position is determined by checking the tire position.