JP4931877B2 - Smart key system - Google Patents

Description

  The present invention relates to a smart key system that includes a portable device and a vehicle control device that controls the operation of a device mounted on the vehicle with the requirement of successful two-way communication with the portable device.

In the smart key system, in order to avoid the failure of two-way communication between the portable device and the vehicle control device due to the influence of electromagnetic wave noise, the reception strength of the three receiving antennas with different directivities built in the portable device is A method of preferentially selecting and using a higher one has been proposed (see Patent Document 1).
Japanese Patent Laying-Open No. 2005-072972

  However, if the noise level around the vehicle is high, the level of the received signal through one receiving antenna becomes high, and if the one receiving antenna is designated as an effective antenna, communication between the portable device and the control device It is likely that the failure will be hampered by. On the other hand, since the effective antenna is designated based on the level of the received signal as described above, even if the designation of the effective antenna is once canceled, the same receiving antenna as before is designated again as the effective antenna, The state where the effective antenna cannot be switched continues.

For example, consider a situation in which the waveform signals shown in the upper, middle, and lower stages on the right side of FIG. 5 can be received by the first, second, and third receiving antennas, respectively. The waveform signals shown in the upper, middle, and lower stages on the right side of FIG. 5 are superimposed signals of the synchronization signal and activation code shown in the upper, middle, and lower stages on the left side of FIG. 5 and noise around the vehicle. . In this situation, when the level of the received signal by each receiving antenna shown on the right side of FIG. 5 is measured at time t ₁ , the first receiving antenna having the highest level is designated as the effective antenna. However, in the received signal through the first receiving antenna, the end of the synchronization signal transmission continuation period cannot be recognized because the noise waveform is obstructed, so it is determined that it is necessary to redesignate the effective antenna (FIG. 5). (See upper right / NG1). Therefore, when the level of the received signal by each receiving antenna shown on the right side of FIG. 5 is measured again at time t ₂ (> t ₁ ), the first reception whose level is still the highest due to the high noise level. The antenna is again designated as the effective antenna. However, in the received signal through the first receiving antenna, it is determined that the noise waveform has hindered the end of the synchronization signal transmission continuation period, and that the communication up to that point has failed (FIG. 5, upper right / NG2 reference).

  Therefore, an object of the present invention is to provide a smart key system that can improve the success probability of bidirectional communication between the portable device and the control device even when the noise level around the vehicle is high.

A smart key system according to a first aspect of the present invention includes a portable device and a vehicle control device that controls an operation of a device mounted on the vehicle based on a communication result with the portable device, and the portable device includes the vehicle control device. Is a smart key system that synchronizes with the vehicle control device in response to detecting the end of the synchronization signal transmission continuation period, and then recognizes the first signal transmitted from the vehicle control device as an activation signal. The portable device includes a plurality of reception antennas having different directivities and a transmission antenna, and one of the plurality of reception antennas has the highest received signal level. And a second signal is transmitted through the transmission antenna on the condition that the activation signal has been successfully recognized. Write, if it fails to recognize the end of the transmission duration of the synchronizing signal in the designated time period, the re-specify a valid antenna, recognition of the end of the transmission duration of the synchronizing signal in successive periods after said specified period of time The vehicle control device receives the second signal, operates the device on the condition that the portable device has been successfully authenticated based on the second signal, and the noise level around the vehicle is When the noise level is equal to or higher than the threshold, the synchronization signal transmission duration is extended as compared with the case where the noise level is lower than the threshold.

  According to the smart key system of the first invention, when the communication environment around the vehicle is so bad that communication between the portable device and the vehicle control device is hindered, the transmission duration of the synchronization signal by the vehicle control device is extended. Thus, when the end of the synchronization signal transmission continuation period within the specified period is not recognized through the effective antenna in a situation where the communication environment around the vehicle is poor, the effective antenna is redesignated. Since a receiving antenna different from the previous effective antenna can be designated as the effective antenna, the success probability of the two-way communication between the portable device and the vehicle control device can be improved even when the noise level around the vehicle is high. In addition, the operation of the on-vehicle equipment requires a successful two-way communication between the portable device existing outside the vehicle and the vehicle control device, such as door locking or unlocking (or the successful authentication of the portable device associated therewith). Means the operation of any in-vehicle device controlled.

A smart key system of a second invention is the smart key system of the first invention, wherein the device includes a door lock actuator for locking or unlocking a door, and the vehicle control device is present around the vehicle. An external communication antenna for communicating with the vehicle, and detecting a noise level in the vicinity of the vehicle based on an electromagnetic wave intensity in the periphery of the vehicle detected by the external communication antenna, or the device is not operated The number of detections of an event that triggers the locking or unlocking of the door in the state is measured as the noise level.

  According to the smart key system of the second invention, the noise level is detected by the vehicle communication antenna, or the number of events detected that triggers device operation when the device is not operating is measured as the noise level. Since a receiving antenna different from the previous effective antenna can be designated as the effective antenna according to the noise level as described above, the noise level around the vehicle that is detected based on the electromagnetic wave intensity detected by the communication antenna for vehicle exterior Even when the value is high, the success probability of bidirectional communication between the portable device and the vehicle control device can be improved.

  An embodiment of a smart key system of the present invention will be described with reference to the drawings. The smart key system shown in FIG. 1 includes a portable device 1 and a vehicle control device 2 mounted on the vehicle.

  The portable device 1 includes a portable device control device 10 built in a resin case (not shown), a reception circuit 11, a transmission circuit 12, a selection circuit 102, a first reception antenna 111, a second reception antenna 112, and A third receiving antenna 113 and a transmitting antenna 120 are provided. The portable device control device 10 is configured by a computer (configured by a CPU, ROM, RAM, I / O circuit, etc.). The case of the portable device 1 has, for example, a rectangular plate shape, and each of the three antennas 111, 112, and 113 has a long side direction (x direction), a short side direction (y direction), a thickness direction (z direction), and the like. Are arranged or arranged so as to have directivity in each of three directions orthogonal to each other. The portable device 1 is formed to be lightweight and compact so that it can be carried in a form such as being put in a pocket of clothing by a user such as a vehicle driver. The reception sensitivity of each reception antenna may be the same, the reception sensitivity of the first reception antenna 111 is higher than the reception sensitivity of the second reception antenna 112, and the reception sensitivity of the second reception antenna 112 is the reception sensitivity of the third reception antenna 113. The receiving sensitivity of each receiving antenna may be different, such as higher than the sensitivity. The receiving circuit 11 receives a signal from the outside through an effective antenna, demodulates this signal into a pulse signal, and outputs it to the portable device control device 10. The transmission circuit 12 modulates a signal output from the portable device control device 10 into a signal having a predetermined frequency and transmits the signal to the outside through the transmission antenna 120.

  The portable device control device 10 designates one of the three reception antennas 111, 112, and 113 as an “effective antenna” for receiving a transmission signal from the vehicle control device 2. The portable device control device 10 causes the selection circuit 102 to switch the effective antenna by transmitting a control signal to the selection circuit 102. In addition to or instead of the selection circuit 102, an invalidation circuit that switches connection and disconnection between the receiving antennas 111 to 113 and the portable device control device 10 may be provided, and the valid antenna may be switched by the invalidation circuit. . When the portable device control device 10 fails to recognize the end of the synchronization signal transmission continuation period within the designated period based on the received signal through the effective antenna, the portable device control apparatus 10 designates the effective antenna again.

  The vehicle control device 2 is constituted by an ECU (electronic control unit (CPU, ROM, RAM, I / O circuit and a data bus connecting them). The vehicle includes a transmission circuit 21, a reception circuit 22, an in-vehicle transmission antenna 211, an in-vehicle transmission antenna 212, an out-of-vehicle reception antenna 221, an in-vehicle reception antenna 222, a first task execution device 241, A two-task execution device 242 is mounted. The vehicle exterior transmission antenna 211 is disposed in the driver's seat door and the passenger seat door, and the vehicle interior transmission antenna 212 is disposed near the center of the interior space of the vehicle 1. The transmission circuit 21 modulates the signal output from the vehicle control device 2 into a signal having a predetermined frequency, and transmits this signal via the in-vehicle transmission antenna 211 or the in-vehicle transmission antenna 212. The vehicle exterior reception antenna 221 is disposed in the driver's seat door and the passenger seat door, and the indoor reception antenna 222 is disposed near the center of the vehicle interior space. The reception circuit 22 receives a signal from the portable device 1 via the vehicle external reception antenna 221 or the indoor reception antenna 222, demodulates this signal, and outputs it to the vehicle control device 2.

  The vehicle control device 2 executes the first task on the condition that the two-way communication with the portable device 1 through the vehicle transmitting antenna 211 and the vehicle receiving antenna 221 is successful (or the authentication of the portable device 1 due to the two-way communication). The device (corresponding to “the device mounted on the vehicle” in the present invention) 241 is caused to execute the “first task”. For example, when the “first task” is door locking or unlocking, the door is locked or unlocked by the vehicle control device 2 by a door lock actuator as the first task execution device 241. When the “first task” is a part or all of the window, the window is opened by the window actuator as the first task execution device 241. The vehicle control device 2 executes the second task on the condition that the successful bidirectional communication with the portable device 1 through the in-vehicle transmission antenna 212 and the in-vehicle receiving antenna 222 (or the successful authentication of the portable device 1 associated with the two-way communication) is a requirement. The device 242 is caused to execute the “second task”. For example, when the “second task” is engine start, the engine is started by the engine starter as the second task execution element 242. When the “second task” is control of the in-vehicle temperature, the in-vehicle temperature is controlled by the air conditioner device as the second task execution element 242. The vehicle control device 2 measures the noise level in the vicinity of the vehicle through the outside receiving antenna 221 or senses an event that triggers the locking or unlocking of the door, and the noise level or the number of times the event is sensed is greater than or equal to the threshold value. In this case, the transmission continuation period of the synchronization signal through the vehicle transmission antenna 211 is extended.

The function of the smart key system configured as described above will be described. First, processing contents executed by the portable device 1 will be described. The level of the received signal of each receiving antenna 111-113 is measured (FIG. 2 / S102). Then, the receiving antenna having the highest received signal level is designated as the effective antenna (FIG. 2 / S104). For example, consider a situation in which the waveform signals shown in the upper, middle, and lower stages on the right side of FIG. 4 can be received by the first receiving antenna 111, the second receiving antenna 112, and the third receiving antenna 113, respectively. The waveform signals shown in the upper, middle, and lower stages on the right side of FIG. 4 are superimposed signals of the synchronization signal and activation code shown in the upper, middle, and lower stages on the left side of FIG. 4 and noise around the vehicle. . If the level of the signal received by the reception antennas 111 to 113 shown in FIG. 4 right at time t ₁ in this situation is determined, the level is highest in the first reception antenna 111 is designated as an active antenna. Further, even in the situation shown in FIG. 5, as described above, the first receiving antenna 111 having the highest received signal level at time t ₁ is designated as the effective antenna.

Furthermore, the success or failure of recognition of the end of the synchronization signal transmission continuation period in the designated period is determined based on the received signal through the effective antenna (S106 in FIG. 2). Here, when it is determined that recognition of the end of the transmission duration of the synchronization signal has failed (FIG. 2 / S106... NO), the levels of the reception signals of the receiving antennas 111 to 113 are measured again (FIG. 2 / S102). ), An effective antenna is designated (FIG. 2 / S104). For example, in the received signal through the first receiving antenna 111, the synchronization signal transmission continuation period is extended as will be described later, so that the synchronization signal transmission continues at time t ₁ as shown in the upper left part of FIG. It is determined that recognition of the end of the period has failed (see the upper right side of FIG. 4 / NG1). Therefore, when the level of the received signal by each of the receiving antennas 111 to 113 shown on the right side of FIG. 4 is measured again at time t ₂ (> t ₁ ), the synchronization signal with an extended transmission duration as will be described later. The third receiving antenna 113 having the highest level is designated as an effective antenna in place of the first receiving antenna 111.

  On the other hand, if it is determined that the end of the transmission duration of the synchronization signal has been successfully recognized (FIG. 2 / S106... YES), the activation code (first signal) has been successfully recognized based on the received signal through the effective antenna. Is further determined (S108 in FIG. 2). For example, in the received signal through the third receiving antenna 113 that is a new effective antenna, it is determined that the end of the synchronization signal transmission continuation period has been successfully recognized (see the lower right / OK in FIG. 4).

  When it is determined that the activation code has been successfully recognized (FIG. 2 / S108... YES), the ID code is transmitted through the transmission antenna 120 (FIG. 2 / S110). The success or failure of recognition of the challenge code based on the received signal through the effective antenna (transmitted from the vehicle control device 2 on the condition that the authentication of the portable device 1 based on the ID code is successful as described later) is determined ( FIG. 2 / S112). If it is determined that the challenge code has been successfully recognized (FIG. 2 / S112... YES), a response code (second signal) is transmitted through the transmission antenna 120 (FIG. 2 / S114). As will be described later, the vehicle control device 2 executes the first task, that is, locking or unlocking the door of the vehicle in response to the reception of the response code. On the other hand, if the activation code recognition fails (FIG. 2 / S108... NO) or the challenge code recognition fails (FIG. 2 / S112... NO), the process is performed without transmitting the ID code or the response code. finish.

  Then, the processing content performed by the vehicle control apparatus 2 is demonstrated. The presence or absence of an event that triggers the locking or unlocking of the door is detected (FIG. 3 / S202). For example, a change in the capacitance of the door or the doorknob when the user brings his hand close to the doorknob is detected as the event. When an event is detected (FIG. 3 / S202... YES), the noise level around the vehicle is measured through the outside receiving antenna 221 (FIG. 3 / S204), and whether or not the measured noise level is equal to or higher than a threshold value. It is determined (FIG. 3 / S206). When it is determined that the noise level is equal to or higher than the threshold (FIG. 3 / S206... YES), the duration of the synchronization signal transmitted through the vehicle-mounted transmission antenna 211 is extended (FIG. 3 / S208). Thus, for example, the synchronization signals shown in the upper, middle and lower stages of the left side of FIG. 4 have a longer duration than the normal synchronization signals shown in the upper, middle and lower stages of the left side of FIG. It is transmitted through the transmission antenna 211. On the other hand, if it is determined that the noise level is less than the threshold (FIG. 3 / S206... NO), the transmission duration of the synchronization signal is not extended (FIG. 3 / S210). Thus, for example, as shown in the upper left, middle and lower stages in FIG. 5, a synchronization signal having a normal duration is transmitted through the vehicle-mounted transmission antenna 211. Instead of the noise level, the number of repeated detections of the event that triggers the door locking or unlocking is measured, and the duration of the synchronization signal is extended when the number of times is equal to or greater than the threshold. It may be. Further, the synchronization signal transmission duration may be extended when the number of synchronization signal end recognition failures is equal to or greater than a specified number.

  Subsequently, the activation code (first signal) is transmitted through the vehicle-mounted transmission antenna 211 (FIG. 3 / S212), and whether or not the ID code transmitted from the portable device 1 is received according to the activation code is determined as described above. (FIG. 3 / S214). If it is determined that the ID code has been successfully received (FIG. 3 / S214... YES), whether the portable device 1 is successfully authenticated based on the ID code is determined (FIG. 3 / S216). Specifically, the success or failure of authentication of the portable device 1 is determined depending on whether or not the ID code matches the ID code stored in the memory of the vehicle control device 1. When it is determined that the authentication of the portable device 1 is successful (FIG. 3 / S216... YES), the challenge code is transmitted through the vehicle-mounted transmission antenna 211 (FIG. 3 / S218). Further, as described above, whether or not the response code (second signal) transmitted from the portable device 1 is received according to the challenge code is determined (S220 in FIG. 3). When it is determined that the response code has been successfully received (FIG. 3 / S220... YES), the first task execution device 241 locks or unlocks the door (FIG. 3 / S222). On the other hand, when it is determined that reception of the ID code has failed (FIG. 3 / S214... NO), when it is determined that reception of the ID code has failed (FIG. 3 / S216... NO), reception of the response code has failed. If it is determined that the communication has failed (FIG. 3 / S220... NO), the user is notified that the communication has failed (FIG. 3 / S224). For example, a message or voice indicating that the two-way communication between the portable device 1 and the vehicle control device 2 has failed is output through a voice output device mounted on the vehicle, and in addition to or instead of being mounted on the vehicle. LED is turned on. If it is determined that reception of the ID code has failed (FIG. 3 / S214... NO), if it is determined that reception of the ID code has failed (FIG. 3 / S216... NO), or reception of the response code has failed. When it is determined that the notification has been made (FIG. 3 / S220... NO), the notification may be omitted and the series of processes may simply be terminated.

According to the smart key system that exhibits the above function, when the communication environment around the vehicle is bad enough to prevent communication between the portable device 1 and the vehicle control device 2, the duration of the synchronization signal transmitted from the vehicle control device 2 Is extended (see FIG. 3 / S206... YES, S208, FIG. 4 and FIG. 5). As a result, the end of the synchronization signal transmission continuation period within the specified period is not recognized through the effective antenna in a situation where the communication environment around the vehicle is bad, so that the effective antenna is redesignated (FIG. 2 / S106... NO, S102). , S104, see FIG. 4 / NG, time t _2). And since a receiving antenna different from the previous effective antenna can be designated as an effective antenna, even when the noise level around the vehicle is high, the success probability of bidirectional communication between the portable device 1 and the vehicle control device 2 is improved. The success probability of tasks such as door locking or unlocking can be improved (see FIGS. 2, 3, and 4 / OK).

Configuration explanatory diagram of the smart key system of the present invention Flow chart showing contents of execution process by portable device Flowchart representing execution process contents by vehicle control device Explanatory diagram related to successful communication of smart key system Explanatory drawing about communication failure example of smart key system

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Portable machine, 2 ... Vehicle control apparatus, 111-113 Receive antenna, 120 ... Transmit antenna, 211 ... Transmit antenna for vehicle exterior, 212 ... Transmit antenna for vehicle interior, 221 ... Receive antenna for vehicle exterior, 222 ... Receive antenna for vehicle interior

Claims (2)

A portable device and a vehicle control device that controls the operation of a device mounted on the vehicle based on a result of communication with the portable device, and the portable device ends an end of a synchronization signal transmission duration by the vehicle control device. A smart key system that recognizes a first signal transmitted from the vehicle control device as an activation signal after synchronization with the vehicle control device in response to detection of
The portable device includes a plurality of reception antennas and transmission antennas having different directivities, and receives a transmission signal from the vehicle control device through one reception antenna having the highest received signal level among the plurality of reception antennas. And the second signal is transmitted through the transmission antenna on the condition that the activation signal has been successfully recognized, while the end of the synchronization signal transmission continuation period in the designated period fails to be recognized. the case, the re-specify a valid antenna, re-attempt to recognize the end of the transmission duration of the synchronizing signal in successive periods after said specified period,
The vehicle control device receives the second signal, operates the device on the condition that the portable device is successfully authenticated based on the second signal, and a noise level around the vehicle is equal to or higher than a threshold value In the case, the smart key system is characterized in that the transmission duration of the synchronization signal is extended as compared with the case where the noise level is less than the threshold. The smart key system according to claim 1, wherein
The device includes a door lock actuator for locking or unlocking the door;
The vehicle control device includes an external communication antenna for communicating with the portable device existing in the periphery of the vehicle, and the periphery of the vehicle based on the electromagnetic wave intensity in the periphery of the vehicle detected by the external communication antenna A smart key system characterized in that the number of times of detection of an event that triggers a door lock or unlock when the device is not operated is measured as the noise level.

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