Tag reader for tyre condition monitoring

The present invention relates to radio communication devices relating to vehicle tires for reporting a tire condition.

As vehicles become more sophisticated, vehicle designers are changing more and more parameters to change performance and improve safety. One of the parameters that can be modified to change performance is the pressure in the vehicle's tires. Unintended changes in tire pressure in the vehicle can cause unwanted changes in performance. These changes in performance can include not only changes in fuel consumption but also safety. Efforts have been made to control the pressure in the vehicle's tires. Apart from pressure control tires, it is also necessary to transmit data from the control point to the place where the information can be used.

Wire communication is unrealistic due to tire rotation. Because the pressure control device must be attached to the tire, preferably inside, the rotation of the tire will prevent wired communication. Radio communication offers many advantages and offers several systems. In a simple proposal, the transponder can be positioned inside the vehicle and connected to a pressure recorder. The interrogator interrogates the transponder over radio and the transponder provides information from the pressure transducer.

Due to different vehicle designs, it is advisable to have transponder designs of different designs. The presence of a larger number of transponder designs allows designers a greater choice when integrating transponders into vehicles and, as a result, may result in better design. Until now, there was a lack of knowledge on how to place the interrogator in a vehicle. Because the transponder responses are parameters of the transducer system, they can be changed depending on the requirements of the interrogator. Using a dual mode or multi-mode transponder in this way can benefit the designer.

The present invention relates to the use of a radio communication device on a tire to control the condition of the tire and to transmit information about the condition of the tire using an interrogator.

Checking the condition of a tire on a vehicle can be done when the vehicle is stationary or in motion. Special consideration must be made when using a request counter on a vehicle to determine the condition of the tire by an answering machine or radio frequency identification (RFID) associated with the tire. The transponder on the tire may not always be within the range of the request counter during tire rotation when the vehicle is moving. Two aspects of the present invention are intended to give vehicle designers greater choice when using interrogators and transponders to control vehicle tire pressure. The latter position provides additional functionalities for the transponder.

The first aspect of the present invention comprises distributing the interrogator unit under the vehicle in various forms to provide designers with flexibility in positioning vehicle elements. In the first embodiment, the interrogator is located along the wheel well along with sufficient processing power to determine the tire pressure from the transponder data. The output of the interrogator is sent to the vehicle control system for use. The output energy is sent to the interrogator.

In a second embodiment, energy is sent from the vehicle control system and the interrogator returns a group spectrum signal that the vehicle system processes to determine the tire pressure.

In the third embodiment, only the antenna is located in the wheel well. The transponder receives a modulated signal and directs it to the vehicle control system for all processing operations.

Another aspect of the present invention relates to how a tire-related transponder is interrogated. Due to electromagnetic radiation, the device may use relatively little power due to the request. For example, if the interrogator is located in the wheel rim of the vehicle, the transponder may not respond when it is in the lower rotation of the tire. In this way, it may be desirable to interrogate the transponder only when the transponder is in the upper part of the tire rotation, in order to obtain a proper response, save energy and time, or reduce radiation. This aspect of the invention determines where the transponder is located during tire rotation and interrogates the transponder only when it is closest to the interrogator.

An example methodology for determining the transponder position includes interaction with the vehicle control system to determine wheel orientation, and empirical positioning and interaction with the vehicle control system to track its position with velocity changes. Some embodiments of the antenna design to improve communication between the transponder and the interrogator are related to this aspect.

A third aspect of the present invention provides a dual mode transponder which responds in different ways based on the type of request signal received. In the first mode, the transponders work in a rival access protocol and allow data to be recorded when the transponders have associated memory. Contest access allows an individual requesting device to address multiple transponders simultaneously. The transponder may enter a second mode based on the type of signal the transponder receives. In an exemplary embodiment, if the transponder enters a radio frequency field for a predetermined time period, but the radio frequency field does not have an amplitude modulation data modulation scheme, the transponder transmits readings from the pressure transducer and controls the results as soon as the radio frequency field is appropriate.

One skilled in the art will appreciate the scope of the present invention and will understand further aspects thereof, having read the following detailed description of preferred embodiments, with reference to the drawings.

The accompanying drawings, which form part of this description, illustrate several aspects of the present invention and serve, in conjunction with the description, to explain the principles of the invention.

FIG. 1 shows a vehicle fitted with a tire fitted with a pressure gauge according to an embodiment of the present invention

FIG. 2 shows a tire fitted with a transponder and a pressure transducer assembly according to an embodiment of the present invention

FIG. 3A-3C illustrate three variants of an interrogator arrangement according to one aspect of the present invention

FIG. 4 is a side elevational view of an interrogator and transponder interacting in a wheel well;

FIG. 5 illustrates a first embodiment of an antenna structure for use with the present invention;

FIG. 6 shows a second embodiment of an antenna construction for use with the present invention;

FIG. 7 is a schematic diagram of a first embodiment of a transponder position on a portion of the interrogator;

FIG. 8 is a diagram showing the positioning of the interrogator and its inputs on the transponder position;

FIG. 9 is a schematic diagram of a second embodiment of a transponder position on a portion of the interrogator; and

FIG. 10 is a schematic diagram of a preferred embodiment of the dual mode functions of the present invention.

The following embodiments provide necessary information to a person skilled in the art on how to apply the invention and illustrate the best way to apply the invention. Reading the following description, with reference to the accompanying drawings, will be apparent to one of ordinary skill in the art, and will be understood by reference to the present invention, and not only as set forth herein. It should be made clear that these concepts and uses fall within the scope of this publication and definition.

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This invention is intended to provide designers with vehicle and tire choices. While attempting to provide more information to the vehicle regulator, the tire pressure or other condition of the tire may be recorded and transmitted by radio with an answering machine and interrogator, the present invention illustrates several embodiments of these elements for selecting additional features and designs when requesting a query system. on the condition of the vehicle tire.

FIG. 1 shows a vehicle 10 with a body 12 and tires 14 as usual. The housing 12 may define the boundaries of the wheel wells 16 in which the tires 14 are substantially contained during operation of the vehicle. The vehicle regulator 18 may be coupled to the vehicle 10 and disposed within the housing 12. The transponder 20 may be disposed in one tire or in multiple tires 14 and radio communication with a respective interrogator 22 disposed at least partially in respective wheel bays 16 or at other locations closest to the tires 14 sufficient to establish radio communication with the transponder.

20.

FIG. 2 shows a more detailed view of tire 14 with associated transponder 20. The tire 14 may comprise a rim 24 and a tread member 26, as will be understood.

A transponder 20 disposed within the tire 14 may include an antenna 28 and a radio circuit 30. The tire condition transducer 32 may be associated with an transponder 20. The tire condition transducer 32 may be a pressure transducer, a temperature transducer, a humidity transducer, a tread transducer, or any other a type of sensor that measures or records the environmental conditions associated with a tire 14 or the conditions around a tire 14. The radio communication circuit 30 and the tire condition sensor 32 may be integrated in a single unit as required or decided. Further information about the radio circuit 30, the antenna 28, and the tire condition sensor 32 can be found in U.S. Patents 5,181,423; 4,529,961; 5,473,938; 6,087,930; 5,977,870; 5,562,787; 5,463,374; 5,844,130; U.S. Patent Nos. 5,541,574 and 4,160,971; No. 10/164459, filed June 6, 2002, and entitled "Capacitive Pressure Gauge," all of which are hereby incorporated by reference. In an exemplary embodiment, the radio communication circuit 30 comprises ONETAG ™ as shown in U.S. Patent Application Ser. No. 09 / 678,271, filed Oct. 3, 2000, entitled "Radiocommunication Device and Method", or MICROINSERT ™, as disclosed in U.S. Pat. No. 09 / 618,505, filed July 18, 2000, entitled "Radio Equipment and Method," both of which are incorporated by reference and sold by the assignee of the present invention. These units are compatible with INTELLITAG transponders sold by INTERMEC (6001 36th Avenue West, Everett, WA 98203-9280). U.S. Patent Application No. 60 / 378,384, entitled "RFID Temperature Device and Method," discloses a temperature sensor, which is incorporated herein by reference. An example of a humidity sensor is described in U.S. Pat. 6,342,295, entitled "Humidity Sensor", incorporated herein by reference. An example of a tread sensor is described in U.S. Pat.

6,028,503, entitled "Tire Tread Detection System", incorporated herein by reference. It should be noted that any type of sensor can be used as a tire condition sensor 32.

The transponder 22 is shown schematically in Figs. 3A-3C. The transponder 22 may include an antenna 34, a detector 36, and a group spectrum processor 38. Further, filters, mixers and the like may be understood to follow. The transponder 22 may be arranged in several different ways to provide an additional design option for the vehicle. As shown in Figs. 3A, Antenna 34, Detector 36, and Group Spectrum Processor 38 - all integrated in a single unit and disposed in a wheel well 16. Processed data and power go to and from vehicle controller 18 and group spectrum processor 38 via communication 40.

FIG. 3B illustrates an embodiment wherein the group spectrum processor 38 is integrated into the vehicle controller 18 but the antenna 34 and the detector 36 are integrated into a separate unit and located in the wheel well 16. Demodulated but raw signal and power go to the vehicle controller 18 and detector 36 and of which through connection 42.

FIG. 3C shows a third embodiment in which the group spectrum processor 38 and the detector 36 are integrated into the vehicle controller 18. Only the antenna is located in the wheel well 16. Raw and unmodulated signals and power go to and from the antenna 34 and the group spectrum processor 38.

Together, these three embodiments provide a variety of application choices for the designer when incorporating transponders in vehicles. As previously noted, the greater number of options allows designers flexibility and improves the likelihood of having the right design that meets the designer's criteria. It should be noted that these three embodiments do not correspond to an INTERMEC device, but that any person skilled in the art can place INTERMEC elements on such devices.

Other aspects of the present invention may now be discussed with these techniques. In the past, some systems were continuously receiving information from transponder 20 with interrogator 22. This wasted energy, raising the issue of electromagnetic compatibility as well as the frequency-current converter issue. As vehicles become more sophisticated, with more electronics, the risk of interference and transient RF emissions become much more serious. So the ability to query selectively can give designers more choices on these things. The selective query may also protect the requesting device 22 from making false requests for transponders 20 located next to vehicles or transponders 20 placed on other tires 14 of the vehicle 10. If all of these are in the design phase, another matter is speed. Typically, the interrogator 22 must first transmit a data sequence to initiate a scan from the tire condition sensor 32. This is followed by the reception of data from the transponder 20. This request and response take some time. If the transponder 20 is not in the field of view, the first byte of the original data sequence is sent, the remainder of the message is lost, and the transponder 20 must remain in the field until another message is sent, duplication of time required and vehicle speed at which transponder 20 is readable . Precise tuning ensures that only one protocol cycle can be required to read data, which allows for maximum speed.

As shown in Figs. 4, the interrogator 22 generates an electromagnetic field 46, which in the exemplary embodiment is a leaf-shaped field. Field 46 exact frequency is a project choice but usually a radio frequency field. It may be appropriate to interrogate transponder 20 when transponder 20 is in field 46. Thus, the transponder 20 must be positioned at an extreme position 48 such that the request should begin as soon as transponder 20 enters field 46. FIG. 7th and 9 illustrate two methods for determining the position 48 of the transponder 20. From the boundary position 48, it is time to start transponder 20 request.

Armed with the time available to interrogate the transponder 20, it is possible to make changes to the antenna design such that a focused request occurs. The main purpose is to optimize the communication between the interrogator 22 and the transponder 20 so as to obtain an almost continuous connection. One way to achieve this is by using multiple antennas. If multiple antennas are transmitted simultaneously, the radiation pattern of the group may be deformed by interference induced by the null.

Since the position and velocity of the transponder 20 are known, the antenna only requires communication with the transponder 20 through the narrowest arc of the wheel 14. In addition, multiple antennas may be actuated sequentially based on known position and velocity, thereby directing any associated deformation. FIG. 5 and 6 show the construction of such two antennas. In the first embodiment, FIG. A plurality of transmission antennas 72 are used in conjunction with a separate receiving antenna 74. In the embodiment, five antennas 72A-72E are shown, although it is to be understood that fewer or more transmission antennas 72 may be used if required or so decided. Transmission antennas 72A-72E generate corresponding electromagnetic chart sheets 76A-76E. Leaves 76A-76E are narrow and extend substantially far to reach the probable position of transponder 20. The transponder 20 responds with an electromagnetic signal received by the receiving antenna 74. Since the reflected signal from the transponder 20 typically has a signal-to-noise ratio of 20 dB to 50 dB, it is not necessary that the sheet structure of the receiving antenna 74 be as accurate as the transmission antennas 72.

Another embodiment of FIG. 6 illustrates an embodiment of the antenna structure 70 consisting of a plurality of dual-function antennas 78A-78E arranged around a wheel well 16. Each antenna 78 transmits and receives electromagnetic signals with a focused leaf 80. When the transponder 20 moves through the field of view of the antenna 78, sequentially changing functions to achieve maximum output communication, transmission, critical path, adequate input communication, and reception. For example, initially the first antenna 78A may be in transmission mode while the second antenna 78B may be in receive mode. The remaining antennas 78C-78E may be disconnected. As the transponder 20 moves in front of the second antenna 78B, the second antenna 78B is used for transmission, while the first and third antennas 78A and 78C are used for reception. The remaining antennas 78D and 78E remain disconnected. The transponder 20 can then move to the leaf 80C, substantially facing the third antenna 78C, so that the third antenna 78C is used for transmission and the second and fourth antennas 78B and 78D are used for reception. The first and fifth antennas 78A and 78E are disconnected. This process continues until transponder 20 leaves leaf 80E or last leaf of antenna structure 70.

FIG. 7 shows a first embodiment of positioning of transponder 20.

It is possible that the present invention may be practiced while the vehicle 10 is not operating, but for purposes of illustration, suppose that the invention is carried out while the vehicle is in operation. In this way, the process begins when the vehicle 10 moves (block 100). Initially, before the interrogator 20 overcomes the transponder 20, the interrogator 22 emits an electromagnetic field 46 (block 102).

Transponder 20 enters field 46 as a function of rotation of tire 14 (block 104). Conversely, transponder 20 may be in field 46 as soon as field 46 is triggered. In any case, transponder 20 responds to a request signal (block 106) when well understood. The interrogator 22 or the vehicle controller 18 may determine the elapsed time for the transponder 20 to respond (unit (108). In the event that transponder 20 appears in field 46, or to reduce the likelihood of a false first signal, the setting may wait until the first edge of the response is detected after no response. That is, the detector (vehicle controller 18 or interrogator 22) confirms that there was no response initially, and the interrogator 22 remains active and waits for the response to be detected before measuring the time period to respond. When the edge is detected, by detecting that the signal is received by the interrogator 22, the wait ends and the measurement begins.

From the setting time and the size of the wheel 14, a circular speed of 48 (block

110). The size of the wheel 14 defines the arc through which the transponder 20 passes, and the portion of the arc which is inside the field can be divided at a calculated time to determine a circular velocity. When an absence of response is detected, the interrogator 22 may be turned off (block 112). With the circular speed and the size of the wheel 14, the vehicle controller 18 or the interrogator 22 can calculate a set time until the transponder 20 returns to field 46 (block

114). The portion of the arc that is outside of field 46 is divided by the circular velocity 48 to provide a time estimate.

The interrogator 22 may be turned on or off immediately before the return time (block 116). In a preferred embodiment, the absence of a response should be detected and confirmed, and then the transponder would enter field 46, which would result in a response. Similarly, acceleration and deceleration can be achieved. It is thought that the phrase "immediately before the estimated return time" should be interpreted as allowing acceleration at the maximum possible speed of the vehicle 10.

Once set, vehicle 10 is deactivated (unit 118). If the answer is negative, the process is repeated. If the answer is positive, the process is terminated (block 120). Note that the exact order of events as required is not required, and process rearrangements are under consideration.

FIG. The other embodiment described in Figure 7 may require additional technical measures. Referring to FIGS. 8, in which the vehicle controller 18 is schematically connected to a plurality of inputs. Namely, the vehicle controller 18 is connected to the odometer 50, tachometer 52, axle sensor 54, transmission sensor 56 and / or fuel injection computer 58 as well as the interrogator 22. From the various inputs, the vehicle controller 18 can determine the rotation of the wheel 14 to a certain degree of accuracy, and from the knowledge already available to the vehicle controller 18, the position and speed of the transponder 20 can be determined. Note that not all inputs need to be used, some require more processing than others to determine the speed of the wheels 14. Other sensors or inputs may also be used if required or decided.

Further, the memory 60 in which data is stored, such as the last position of the transponder 20 before the engine is switched off, may be associated with the vehicle controller 18.

With these inputs and references to Figs. 9, a second embodiment of enabling and disabling the positioning of the interrogator 20 in response to the position of the transponder 20 may be explained. Vehicle 10 begins operation (unit 150) when the ignition is switched on. The vehicle controller 18 instructs the memory 60 to determine the last extreme position of the transponder 20 (block 152). This can already be detected and entered at the factory check, by the mechanic who last rotated and / or changed the tires 14, or stored in the memory since the last time the vehicle 10 was operating. In addition, this can be determined empirically, e.g. 7 in the manner indicated.

When the field 46 is activated, the vehicle controller 18 or the interrogator 22 determines whether the transponder 20 is in the field 46 (block 154). If not, vehicle controller 18 may specify inputs, such as axis sensor 54 or transmission sensor 56, to determine the position of transponder 20 and determine its initial position and vehicle speed when transponder 20 enters field 46 (block 156). After setting block 156 or if block 154 responds positively, the interrogator 22 is activated (block 158). If the transponder 20 was outside field 46, then the interrogator 22 is immediately activated prior to the intended arrival of the transponder 20 in field 46.

The interrogator 22 receives the response signal from the transponder 20 while the transponder 20 is in field 46 (block 160). The vehicle controller 18 or the interrogator 22 determines whether the transponder 20 has left field 46 (block 162). If the answer is negative, the process is repeated. If the answer is positive, then the interrogator 22 is turned off (block 164).

The vehicle controller 18 determines whether the vehicle is off (block 166). If the answer is no, the process is repeated as indicated. If the answer is yes, the process is completed (block 168).

Again, as noted above, the exact order of the steps does not need to be linear as indicated, and changes to the order of the steps are discussed, with some steps being performed simultaneously instead of sequentially.

A third aspect of the present invention relates to how the transponder 20 may have at least dual mode functions depending upon the type of radio frequency field in which the transponder 20 is operated. During production, a plurality of transponders 20 and tires 14 may be arranged closest to one another. In such examples, it may be desirable to operate in a first mode so that the transponder 20 responds in the first mode so that the sole interrogator 22 can interrogate the transponder 20 in the same manner as during the production of the tire 14. Plus, it slows down every transponder

20th response time, since the interrogator 22 needs to distinguish between different transponders 20. In addition, when transponder 20 is mounted on a tire 14 operating in vehicle 10, it may be desirable to operate in a second mode such that interrogator 22 and transponder 20 may communicate extensively. rather, since transponder 20 would no longer worry about bandwidth with other transponders 20, then transponder 20 would respond in a second way. Other modes may also be included in the operation of transponder 20, if required or so decided. References are made to Figs. 10, where an action diagram illustrating this dual mode is provided.

Initially, transponder 20 enters the radio frequency field (block 200). This may be a radio frequency field 46 or a field such as that in a production environment. The transponder 20 determines whether there is an amplitude modulation (AM) element for the field (block 202). Conversely, the presence of a known byte will play the same role, in which case the stage becomes equivalent to the transponder stage 20 and determines whether a known byte is present. If the answer is negative, then there is no amplitude modulation element (indicating that the transponder is in a field analogous to field 46), the transponder 20 starts transmitting the pressure data obtained from the tire condition sensor 32 and the control results at this speed and bandwidth as possible 204). The transponder 20 then determines whether the transponder 20 is no longer in the field 46 (block 206). If the answer is negative, the process is terminated (block 208) until a new radio frequency field (block 200) is detected by the transponder 20. If the response to block 206 is positive, the transponder 20 determines whether the field 46 is changed (block 210). If the response to block 210 is negative,₁₂ EN 5313 B process is repeated as indicated. If the response to block 210 is positive, then the transponder may enter modes (block 212).

Further, if the setting in block 202 indicates that there is an amplitude modulation element for field 5 (or if a byte is known), then the transponder 20 may enter the contest access protocol mode (block 214). If necessary or so decided, this may include a multiple time division system, a multiple frequency division system, or the like. An exemplary rival access protocol is based on the carrier registration multiple access protocol commonly used for Ethemet connections.

When acknowledged (block 216), the transponder 20 transmits information and data, this transmission transmits the information requested by the field that forced the transponder 20 to enter this mode (block 218). The transponder 20 may detect that the transponder 20 is still in the field (not shown) and / or determine that the field has been changed (block 220). If the field is changed, transponder 20 can switch modes (block 212). Further, if the field is unchanged, the transponder 20 may repeat the process as instructed.

Whereas what is previously referred to as an amplitude modulation field presence or known byte test, a continuous radio frequency field presence or single modulated continuous speed signal test could equally be used to trigger input to a mode where transponder 20 transmits data from tire condition sensor 32 continuously and as soon as possible. The capability of the speedometer is to change what allows the transponder 20 to use the speedometer (known as accurate) as a reference by which the transponder 20 can measure the output of the tire condition sensor 32.

Note that some setting steps are not accurate and the presence or absence of a field may cause the setting. This is especially true when transponder 20 is more of a passive device than an active device. In addition, the transponder 20, and in particular the radio circuit 30, may include information and memory having complex functions, if necessary or so decided. Note also that the present invention may include and is not limited to the transmission of any type of tire information 14 including pressure.

₁₃ LT 5313 B

Improvements and modifications to the best embodiments of the present invention will be apparent to those skilled in the art. All of these improvements and modifications are within the scope of the concept and appended definition set forth herein. It should be noted that while the pressure of the tire 14 is adjustable, other tire conditions in addition to the pressure or additional pressure may also be adjusted using the present invention.