JP7819938B2 - Safety Systems - Google Patents

Description

The present invention relates to a safety system. In particular, it relates to a system that uses positioning using wideband wireless communication to protect the safety of drivers of motorcycles and other vehicles.

In recent years, jackets equipped with airbags to protect riders of motorcycles and other vehicles from impacts have become popular. These jackets use wireless communication with a device mounted on the vehicle body, and deploy the airbags based on information such as the distance between the vehicle and the rider. (See, for example, Patent Document 1.)

Patent No. 4548731

In the conventional system described in Patent Document 1, which deploys an airbag by referencing the distance between the vehicle body and the rider (driver), the distance is measured by comparing the phase of transmitted and received radio waves. This requires a reference signal on both the transmitting and receiving sides, which poses the issue of temperature drift of the reference signal phase directly leading to measurement errors.

In a previous patent application (Patent Application No. 2023-009041), the above issue was resolved by using ultra-high-precision distance measurement with ultra-wideband (UWB) wireless communication. However, determining airbag deployment solely based on the distance between the rider and the vehicle body was prone to error, particularly when the rider jumped out at an angle to the vehicle body.

The present invention aims to provide a highly accurate safety system by using wideband wireless communication (UWB) to measure not only distance but also position information, and by referring to this information, along with the obtained motion vectors and predicted positions, to determine whether to deploy an airbag.

The invention described in claim 1 is a safety system comprising a mobile object safety device having an antenna attached to a mobile object and a user safety device having an antenna attached to a user of the mobile object, and which performs wideband wireless communication between the mobile object safety device and the user safety device, wherein the wireless signal between the mobile object safety device and the user safety device includes a first reference signal having multiple harmonic components for measuring reception time and a second reference signal composed of a fundamental wave component, and the mobile object safety device includes a basic antenna for transmitting and receiving the wireless signal, one or more accessory antennas for receiving the wireless signal, and a front a receiving time measurement unit that measures the receiving time of a first reference signal of the radio signal received via the basic antenna; a relative angle measurement unit that measures the phase of a second reference signal of the radio signal received via the basic antenna and the accessory antenna and determines the relative angle between the movable body and the user of the movable body from the receiving phase difference between the basic antenna and the accessory antenna; a transmission data creation unit that generates measurement data including the receiving time of the first reference signal transmitted via the basic antenna and the relative angle between the movable body safety device and the user safety device; a mobile object safety device control unit that controls the relative angle measurement unit, the relative angle measurement unit, and the transmission data creation unit, wherein the user safety device comprises a basic antenna that transmits and receives the wireless signal, a transmission data creation unit that generates the first reference signal, the second reference signal, and data including transmission time information of the first reference signal via the basic antenna, a measurement data detection unit that detects the measurement data transmitted from the mobile object safety device via the basic antenna, a user protection device for protecting a user of the mobile object, a driver that drives the user protection device, distance conversion means that converts the transmission time of the first reference signal transmitted by the user safety device and the reception time of the first reference signal detected by the measurement data detection unit into the distance between the mobile object and the mobile object user, Cartesian coordinate conversion means that converts polar coordinates indicated by the relative angle detected by the measurement data detection unit and the distance converted by the distance conversion means into Cartesian coordinates between the mobile object and the mobile object user, and timing means that determines the drive timing of the driver by referring to the Cartesian coordinates of the mobile object and the mobile object user converted by the Cartesian coordinate conversion means.

The invention described in claim 2 is a safety system described in claim 1, characterized in that the user safety device control unit has a motion vector generation means that uses the difference between the current orthogonal coordinate created by the orthogonal coordinate conversion means and the previous orthogonal coordinate as a motion vector, and the timing means determines the drive timing of the driver by referring to the orthogonal coordinate and the motion vector.

The invention described in claim 3 is a safety system described in claim 2, characterized in that the user safety device control unit has a coordinate prediction means for determining predicted orthogonal coordinates after a predetermined time from the motion vector generated by the motion vector generation means and the orthogonal coordinates, and the timing means determines the driver's driving timing by referring to the orthogonal coordinates and the predicted orthogonal coordinates.

The invention described in claim 4 is a safety system described in claim 3, characterized in that the user safety device control unit includes a predicted polar coordinate conversion means for converting the predicted Cartesian coordinates of the coordinate prediction means into predicted polar coordinates displayed as a distance and angle from the origin, an alternative Cartesian coordinate creation means for replacing the distance from the origin of the predicted polar coordinates with the distance between the movable body and the user of the movable body obtained by the distance conversion means and creating alternative Cartesian coordinates by converting the polar coordinates into Cartesian coordinates, and a coordinate selection means for replacing the Cartesian coordinates input to the timing means with the alternative Cartesian coordinates by referring to the relative angle obtained by the relative angle measurement means.

The invention described in claim 5 is a safety system comprising a plurality of movable body safety devices each having an antenna attached to a movable body, and a user safety device each having an antenna attached to a user of the movable body, and which performs wideband wireless communication between the movable body safety devices and the user safety devices, wherein the wireless signal between the movable body safety devices and the user safety devices includes a first reference signal having multiple harmonic components for measuring reception time, and each of the movable body safety devices has a basic antenna for transmitting and receiving the wireless signal, a reception time measurement unit for measuring the reception time of the first reference signal of the wireless signal received via the basic antenna, a transmission data creation unit for generating data including the reception time of the first reference signal transmitted via the basic antenna, and a movable body safety device control unit for controlling the basic antenna, the reception time measurement unit, and the transmission data creation unit, and wherein the user safety device has a basic antenna for transmitting and receiving the wireless signal, a transmission data creation unit for generating data including the first reference signal and transmission time information of the first reference signal via the basic antenna, and a user safety device control unit including: a measurement data detection unit that detects the reception time of the first reference signal transmitted from each mobile body safety device via the basic antenna; a user protection device for protecting the user of the mobile body; a driver that drives the user protection device; distance conversion means that converts the transmission time of the first reference signal transmitted by the user safety device and the reception time of the first reference signal received by each mobile body safety device into the distance between each mobile body safety device and the mobile body user; mobile body safety device coordinate registration means that pre-registers the distance between each mobile body safety device attached to the mobile body; coordinate conversion means that converts the distance between each mobile body safety device and the mobile body user converted by the distance conversion means and the coordinates of the mobile body safety device registered by the mobile body safety device coordinate registration means into relative coordinates between the mobile body and the mobile body user; and timing means that determines the drive timing of the driver by referring to the relative coordinates of the mobile body and the mobile body user converted by the coordinate conversion means.

The invention described in claim 6 is a safety system described in claim 5, characterized in that the user safety device control unit has a motion vector generation means that uses the difference between the current orthogonal coordinate created by the coordinate conversion means and the previous orthogonal coordinate as a motion vector, and the timing means determines the drive timing of the driver by referring to the orthogonal coordinate and the motion vector.

The invention described in claim 7 is the safety system described in claim 6, characterized in that the user safety device control unit has a coordinate prediction means for determining predicted orthogonal coordinates after a predetermined time from the motion vector generated by the motion vector generation means and the orthogonal coordinates, and the timing means determines the driver's drive timing by referring to the orthogonal coordinates and the predicted orthogonal coordinates.

According to the present invention (claim 1), the system comprises a mobile object safety device attached to a mobile object and a user safety device attached to a user of the mobile object. Using wideband wireless communication, the user safety device transmits a first reference signal having multiple harmonic components for measuring reception time and a second reference signal composed of a fundamental wave component between the mobile object safety device and the user safety device. The mobile object safety device then measures the reception time of the first reference signal via the basic antenna and measures the phase of the second reference signal received via the basic antenna and an auxiliary antenna. The relative angle between the mobile object and the user of the mobile object is determined from the reception phase difference between the basic antenna and the auxiliary antenna. The user safety device obtains polar coordinate information consisting of distance and relative angle from the measurement data received in response from the mobile object safety device, and converts this information into Cartesian coordinates to obtain position information (Cartesian coordinate values). This invention uses the obtained position information to determine airbag deployment, thereby providing a highly accurate safety system.

In addition, since position information is used instead of distance information, restrictions on the mounting position of the moving body safety device on the moving body can be reduced.

Furthermore, according to the present invention (claims 2 and 6), airbag deployment is determined by referencing the current position of the user of the mobile body and their movement vector. The movement vector represents the relative speed of the user from the mobile body, and by limiting the target speed for airbag deployment to a predetermined range, unnecessary airbag deployment can be prevented, providing a more effective and accurate safety system.

Furthermore, according to the present invention (claims 3 and 7), the predicted position of the user of the mobile object is calculated from the current position and movement vector of the user of the mobile object. Since the difference between the current position and the predicted position is continuously within a certain value, it is possible to determine whether the airbag should be deployed, thereby providing a faster and more accurate safety system.

Furthermore, according to the present invention (claim 4), predicted Cartesian coordinates can be converted into predicted polar coordinates, and then Cartesian coordinates can be obtained again using the polar coordinates. This makes it possible to provide a highly accurate safety system even when the phase difference in the reception angle of the measured polar coordinates is large and reliability is low.

Furthermore, according to the present invention (claim 5), a system is provided that includes multiple mobile object safety devices attached to a mobile object and a user safety device attached to a user of the mobile object. A first reference signal having multiple harmonic components for measuring reception time and its transmission time information are transmitted from the user safety device using wideband wireless communication between the mobile object safety devices and the user safety devices. Each mobile object safety device then measures the reception time of the first reference signal via the basic antenna. The user safety device calculates distance from the measurement data (reception time) received in response from each mobile object safety device, and performs coordinate conversion to obtain position information (Cartesian coordinate values). This invention uses the obtained position information to determine airbag deployment, thereby providing a highly accurate safety system.

1 is a diagram schematically illustrating a configuration of a safety system according to a first embodiment. FIG. 10 is a diagram schematically illustrating the configuration of a safety system according to a second embodiment. 1 is a diagram illustrating a positioning method of a safety system according to the first embodiment. FIG. 3 is a diagram illustrating conversion from polar coordinates to Cartesian coordinates of the safety system according to the first embodiment. FIG. FIG. 10 is a diagram illustrating a positioning method of a safety system according to a second embodiment. 4 is a flowchart showing a flow of processing by a user safety device control unit of the safety system according to the first embodiment. 3 is a diagram illustrating the structure of a table managed by a user safety device control unit of the safety system according to the first embodiment. FIG.

Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 is a diagram showing a schematic configuration of a safety system 1 according to the first embodiment. This safety system 1 is a system that aims to protect the safety of a motorcycle as the movable object and its driver as the user of the movable object.

The mobile object safety device 100 and the user safety device 200 communicate with each other via wideband wireless communication. The wireless signal includes a first reference signal having multiple harmonic components for measuring reception time and a second reference signal composed of a fundamental wave component. The mobile object safety device 100 is mounted on a mobile object, i.e., a vehicle body of a saddle-type vehicle such as a motorcycle (hereinafter referred to as the vehicle body). The device is attached to the vehicle body, for example, on the handlebars. The basic antenna 113 transmits and receives the wireless signal. The accessory antennas 114 and 115 are antennas for receiving the wireless signal. The reception time measurement unit 112 measures the reception time of the first reference signal of the wireless signal received via the basic antenna 113. The relative angle measurement units 116 and 117 measure the phases of the second reference signals of the wireless signals received via the basic antenna 113 and the accessory antennas 114 and 115, respectively, and calculate the relative angle between the mobile object and the user of the mobile object from the phase difference between the basic antenna and the accessory antenna. The accessory antenna 114 is used to determine the relative angle with respect to the X-axis on the XY plane, and the accessory antenna 115 is used to determine the relative angle with respect to the XY plane. Using these two accessory antennas makes it possible to acquire three-dimensional position information. The transmission data creation unit 111 generates data including the reception time measured by the reception time measurement unit and the respective relative angles measured by the relative angle measurement units 116 and 117, and transmits the data to the user safety device 200 via the basic antenna 113.
The movable body safety device control unit 120 is composed of a processing unit such as a CPU (central processing unit) or an MPU (microprocessor), a storage unit such as a RAM (random access memory), and an input/output interface, and controls the transmission data creation unit 111, the reception time measurement unit 112, and the relative angle measurement units 116 and 117 through software processing.

The user safety device 200 is built into a jacket or the like (hereinafter referred to as the jacket) worn by a user of a mobile object, i.e., a rider of a motorcycle or the like. A transmission data creation unit 211 generates a first reference signal for measuring reception time, data including its transmission time information, and data of a second reference signal, and transmits these to the mobile object safety device 100 via a basic antenna 213. A measurement data detection unit 212 detects measurement data consisting of the reception time and two relative angles received from the mobile object safety device 100 via the antenna 213. The user protection device 240 is a device such as an airbag that is driven by the driver 230 and inflates when the driver determines that there is danger, thereby absorbing impact on the driver and protecting the driver.
The user safety device control unit 220 is composed of a processing unit such as a CPU (central processing unit) or MPU (microprocessor), a storage unit such as RAM (random access memory), and an input/output interface, and realizes its functions through software processing. It also includes a distance conversion unit 221, a timing unit 222, a Cartesian coordinate conversion unit 223, a motion vector generation unit 224, and a coordinate prediction unit 225. The distance conversion unit 221 calculates the time of flight (ToF) of the radio wave from the transmission time of the first reference signal and the reception time of the first reference signal detected by the measurement data detection unit, and multiplies this by the speed of light to calculate the distance between the mobile object and the mobile object user. The Cartesian coordinate conversion unit 223 converts the polar coordinates, represented by the distance acquired by the distance conversion unit 221 and the two relative angles detected by the measurement data detection unit 212, into Cartesian coordinates between the mobile object and the mobile object user. The Cartesian coordinate system has the origin at the position of the mobile object safety device attached to the vehicle (e.g., the handlebars), the X axis representing the direction of the saddle of the vehicle, the Y axis representing the lateral direction of the handlebars perpendicular to the X axis, and the Z axis representing the vertical direction (right-handed system). The motion vector generation means 224 generates a motion vector by calculating the difference between the XYZ coordinate values calculated by the Cartesian coordinate conversion means and the XYZ coordinate values calculated in the previous sampling. The coordinate prediction means 225 calculates predicted coordinates for a predetermined time period from the motion vector generated by the motion vector generation means 224 and the Cartesian coordinate values calculated by the Cartesian coordinate conversion means 223. The timing means 222 determines whether the mobile object user has deviated from the safety zone by referring to the Cartesian coordinate values calculated by the Cartesian coordinate conversion means 223, the motion vector generated by the motion vector generation means 224, and the predicted coordinate values calculated by the coordinate prediction means 225. If the mobile object user has deviated from the safety zone and it is determined that deployment of the user protection device 240 is necessary, the timing means 222 drives the driver 230 to deploy the user protection device (e.g., an airbag). The safety zone of the mobile object user is defined, for example, as a rectangular parallelepiped that includes the mobile object user and is set in advance.

The wireless communication used in the safety system of this embodiment is pulse communication using a wide band (500 MHz), and since the power density per unit frequency is low, it is recognized as noise by existing BLE (Bluetooth Low Energy) and Wi-Fi methods.
In addition, since the pulse is composed of many frequencies, it is also resistant to noise.
Furthermore, the pulse edges are steep, enabling highly accurate (for example, 100 ps) time measurement.The frequency band used is 8 GHz, which causes almost no interference with existing systems.

Distance measurement begins by transmitting a first reference signal for measuring reception time generated in the transmission data creation unit and data including its transmission time information from the user safety device 200 on the jacket side to the movable body safety device 100 on the vehicle body side via the antenna 213, and is performed by responding with the measured reception time of the first reference signal from the movable body safety device 100 on the vehicle body side.
The angle of arrival (AoA) of the radio wave can be calculated from the phase difference when the second reference signal transmitted from the user safety device on the jacket side is received by the basic antenna and the accessory antenna of the mobile body safety device 100 on the vehicle side (details will be described later). From these distances and relative angles, the polar coordinates of the user safety device can be obtained.

The above configuration enables highly accurate positioning that is less susceptible to noise and temperature characteristics, making it possible to build a safety system using this.

FIG. 2 is a diagram schematically illustrating the configuration of a safety system 2 according to the second embodiment.
The structural feature of this embodiment 2 is that, unlike embodiment 1, multiple (three in Figure 2) movable body safety devices are attached to the vehicle body, and each movable body safety device is equipped with only a basic antenna.

In FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals.
The movable body safety device 1 will be described.
The primary antenna 113 transmits and receives the radio signals.
The reception time measurement unit 112 measures the reception time of the first reference signal of the radio signal received via the basic antenna 113. The transmission data creation unit 111 generates transmission data including the reception time measured by the reception time measurement unit 112, and transmits the transmission data to the user safety device 200 via the basic antenna 113. The movable body safety device control unit 120 controls the transmission data creation unit 111 and the reception time measurement unit 112.

The movable body safety devices 2 and 3 have the same configuration as the movable body safety device 1. These devices are arranged, for example, with the movable body safety device 1 in the center of the handle of the vehicle body, and the movable body safety devices 2 and 3 on the left and right of the handle.
The reception time measurements of the movable body safety devices 1 to 3 are different because they are at different distances from the user safety device.

The user safety device 200 is built into a jacket or the like (hereinafter referred to as the jacket) worn by a user of the mobile object, i.e., a rider of a motorcycle or the like. A transmission data creation unit 211 generates data including a first reference signal for measuring reception time and its transmission time information, and transmits the data to the mobile object safety device 100 via a basic antenna 213. A measurement data detection unit 212 detects measurement data consisting of the reception times received from each of the mobile object safety devices 1 to 3 via the antenna 213. The user protection device 240 is a device such as an airbag that is driven by the driver 230 and inflates when the driver determines that there is danger, thereby absorbing impact on the driver and protecting the driver.
The user safety device control unit 220 is composed of a processing unit such as a CPU (Central Processing Unit) or an MPU (Microprocessor), a storage unit such as a RAM (Random Access Memory), and an input/output interface, and realizes its functions through software processing. It includes a distance conversion means 221, a timing control means 222, a coordinate conversion means 223, a motion vector generation means 224, a coordinate prediction means 225, and a movable body safety device coordinate registration means 226.
The distance conversion means 221 calculates the time of flight (ToF) of each radio wave from the transmission time of the first reference signal and the reception time of the first reference signal from each movable body safety device 1 to 3 detected by the measurement data detection unit, and multiplies this by the speed of light to calculate the distance between each movable body safety device 1 to 3 and the movable body user.
The coordinate conversion means 223 calculates the Cartesian coordinate values of the user safety device from the distance between each movable body safety device 1 to 3 and the user safety device obtained by the distance conversion means 221 and the coordinate values of the movable body safety device registered by the movable body safety device coordinate registration means 226.
The motion vector generation means 224 generates a motion vector by calculating the difference between the XYZ coordinate values calculated by the coordinate conversion means 223 and the XYZ coordinate values calculated in the previous sampling. The coordinate prediction means 225 calculates predicted coordinates for a predetermined time from the motion vector generated by the motion vector generation means 224 and the orthogonal coordinate values calculated by the coordinate conversion means 223. The timing means 222 determines whether the user of the mobile object has deviated from the safety zone by referring to the orthogonal coordinate values calculated by the coordinate conversion means 223, the motion vector generated by the motion vector generation means 224, and the predicted coordinate values calculated by the coordinate prediction means 225. If it is determined that the user has deviated from the safety zone and that deployment of the user protection device 240 is necessary, the timing means 222 drives the driver 230 to deploy the user protection device (airbag, etc.).

<Positioning method>
The positioning method of this safety system will now be described.
FIG. 3 is a diagram illustrating the angle of arrival (AoA) method in the first embodiment.
The user safety device is on the jacket side (tag), and the moving body safety device is on the vehicle body side (anchor).
Distance measurement is performed by transmitting a first reference signal carrying transmission time information from the tag, measuring the time it receives the first reference signal at the anchor, and then transmitting the reception time from the anchor to the tag, which calculates the radio wave flight time and multiplies it by the speed of light (approximately 300,000 km per second) to calculate the distance. This sequence is performed at predetermined intervals. The sampling interval (e.g., 10 ms) is controlled by the user safety device control unit.

In the angle-of-arrival method, radio waves are received by two antennas. The angle between the direction of arrival of the radio waves and the perpendicular direction of the plane formed by the two antennas is defined as θ. Furthermore, if the difference in the reach of the radio waves (d2 - d1) is defined as Δd and the distance between the antennas is L, then Δd = L sin(θ) (-π/2 < θ < π/2)
is.
If the phase difference between the fundamental waves received by the two antennas is Δφ, and the wavelength is λ, then 2π:λ = Δφ:Δd, so Δd = Δφ λ/2π
therefore,
sin(θ)=λ・Δφ/2π・L θ=arcsin(λ・Δφ/2π・L)
The arrival angle (relative angle) θ can be calculated using the following equation.
It should be noted that L must be λ/2 or less.
Furthermore, when L=λ/4, the angle of arrival is within ±60 degrees.

FIG. 4 is an explanatory diagram of the conversion from polar coordinates to rectangular coordinates.
The three-dimensional polar coordinate values (D, θ1, θ2) can be obtained from the arrival angle (relative angle) θ1 formed by one set of basic antenna and accessory antenna 1 with the X axis on the XY plane, and the arrival angle (relative angle) θ2 formed by another set of basic antenna and accessory antenna 2 with the XY plane, and the distance D.
If the Cartesian coordinate values of the current position P (relative position from the origin) of the tag (user safety device) are (X, Y, Z), then
X=D・cosθ2・cosθ1
Y=D・cosθ2・sinθ1
Z = D sinθ2
(P' is the projection point of P (tag position) onto the XY plane.)
The origin position is set at the handle part of the anchor (vehicle body), etc. The X axis is set in the direction of the saddle of the vehicle body, the Y axis is set in the left-right direction of the handle part, and the Z axis is set in the vertical direction from the origin (right-handed system).

FIG. 5 is a diagram illustrating the multi-anchor method according to the second embodiment.
The anchor movable body safety devices are arranged such that device 1 is located on the handlebar of the vehicle body, and devices 2 and 3 are located on the right and left sides of the handlebar as viewed from the front. The user safety device (tag) is built into the rider's jacket.
The distance measurement between the tag and the anchor is the same as that described in the first embodiment.
If the measured distances between the tag and anchors 1, 2, and 3 are L1, L2, and L3, respectively, and the coordinate values of the anchors are as shown in the figure, the relationship between the X, Y, and Z coordinate values of the lidar (tag) is expressed as equations (1), (2), and (3) in the figure.
These equations can be solved to find the X, Y, and Z coordinate values of the tag.
The X, Y, and Z coordinate values of the anchors 1, 2, and 3 are set at an initial stage by the movable body safety device coordinate registration means.

FIG. 6 is a flowchart showing the flow of processing by the user safety device control unit in the first embodiment.
The flowchart in the second embodiment is the same except for the position measurement method.
FIG. 7 is a diagram illustrating the structure of a table managed by the user safety device control unit.

When the user safety device is powered on, the process starts from the start at a predetermined time interval (sampling period: for example, 10 ms).
In step S101, it is determined whether this is the first time, and if the answer is Yes, in step S102, initialization processing of the control unit's management tables, etc. is performed. This includes initialization of the Cartesian coordinate table, motion vector table, predicted coordinate table, current time pointer, etc. The TDOA method's "movable safety device distance registration" and other settings are also set at this stage. If the answer is No, initialization is bypassed and the process proceeds to step S103.

In step S103, it is determined whether the START button has been pressed. The START button is attached to the user safety device (attached to the jacket), and the rider presses it when he or she has completed riding the motorcycle. Thereafter, sampling of the positioning is started.
If the answer is No, the process ends without doing anything, whereas if the answer is Yes, the process proceeds to step S104.
In step S104, measurement data, that is, reception time Tr and relative angles θ1 and θ2, are acquired from the measurement data detection unit.
In step S105, the distance conversion means calculates the time of flight of the radio wave from the difference between the reception time Tr and the transmission time of the first reference signal, and multiplies this by the speed of light to calculate the distance D between the tag and the anchor.
In step S106, it is determined whether the absolute value of the relative angle acquired in step S104 is within 60 degrees. If the absolute value of the relative angle exceeds 60 degrees, the reliability of the relative angle decreases. If the answer is Yes, the process proceeds to step S109; if the answer is No, the process proceeds to step S107. In step S107, predicted polar coordinates are created from the predicted rectangular coordinates by the predicted polar coordinate conversion means.
In step S108, alternative orthogonal coordinates are created by the alternative orthogonal coordinate creating means, and the process proceeds to step S110.
In step S109, the polar coordinates represented by D and the relative angles θ1 and θ2 obtained in step S105 are converted into XYZ Cartesian coordinates by the Cartesian coordinate conversion means (see FIG. 4 for details). This allows the relative position of the tag, i.e., the rider who is the user of the mobile object, from the origin coordinates to be obtained.
In step S110, this orthogonal coordinate value is recorded in the entry indicated by the current time pointer in the orthogonal coordinate table.
In step S111, a motion vector is calculated by the motion vector generating means, which is the difference between the X, Y, and Z coordinate values of the entry immediately preceding the current time pointer and the X, Y, and Z coordinate values of the entry indicated by the current time pointer.
In step S112, this motion vector information is recorded in the entry indicated by the current time pointer in the motion vector table.
In step S113, the coordinate prediction means calculates predicted coordinate values, which are coordinate values obtained by adding the orthogonal coordinate values indicated by the current time pointer to the motion vector, and are the orthogonal coordinate values predicted for the next sampling time.
In step S114, this predicted coordinate value is recorded in the entry indicated by the current time pointer in the predicted coordinate table.
In step S115, the orthogonal coordinates, the motion vector, and the predicted coordinates acquired in the previous step are referenced to determine whether or not the airbag should be deployed. The coordinates of the safety zone are set at an initial stage, and the orthogonal coordinates, the motion vector, and the predicted coordinates are evaluated to determine whether or not the airbag should be deployed.
The motion vector represents the displacement of the Cartesian coordinate system over a specified time interval, i.e., the rider's relative speed from the vehicle. The target speed for airbag deployment (the magnitude of the motion vector) is set between 15 km/h and 300 km/h, for example. Speeds below 10 km/h are considered normal dismounting behavior, and the airbag is not deployed. Speeds above 300 km/h are also considered an electronic malfunction, and the airbag is not deployed.
The predicted coordinates are evaluated by comparing the predicted coordinate values shown in the previous entry with the current Cartesian coordinate values. If the difference is within a certain value, the movement can be considered to be roughly as predicted, and this is the condition for airbag deployment.
The airbag is deployed when the following three conditions are met: (1) the Cartesian coordinate value is outside the safety zone, (2) the magnitude of the motion vector is within the target speed range, and (3) the difference between the predicted coordinate value and the Cartesian coordinate value is within a certain value.
If the determination in step S116 is Yes, the airbag is deployed in step S118, and sampling ends. By storing the management table in a nonvolatile memory, the situation immediately before the accident (airbag deployment) can be recorded and saved.
If the determination is No, in step S117, the current time pointer is advanced by 1. If the maximum number of entries is exceeded, the process returns to the first entry and is used repeatedly.

The safety system of this embodiment has been described above, but this is merely an example, and it goes without saying that various modifications are possible within the spirit and scope of the present invention.

1 Safety system 100 Movable body safety device 111 Transmission data creation unit 112 Reception time measurement unit 113 Basic antenna 114 Accessory antenna 1
115 Accessory antenna 2
116 Relative angle 1 measurement unit 117 Relative angle 2 measurement unit 120 Movable body safety device control unit 200 User safety device 211 Transmission data creation unit 212 Measurement data detection unit 213 Basic antenna 220 User safety device control unit 221 Distance conversion means 222 Timing means 223 Cartesian coordinate conversion means (coordinate conversion means)
224 Motion vector generating means 225 Coordinate prediction means 226 Movable body safety device coordinate registration means 230 Driver 240 User protection device 300 Movable body safety device 2
400 Movable body safety device 3

Claims (7)

A safety system including a movable body safety device having an antenna attached to a movable body and a user safety device having an antenna attached to a user of the movable body, the safety system performing wideband wireless communication between the movable body safety device and the user safety device,
the wireless signal between the movable body safety device and the user safety device includes a first reference signal having multiple harmonic components for measuring a reception time, and a second reference signal composed of a fundamental wave component;
The movable body safety device is
a basic antenna for transmitting and receiving the radio signal, and one or more accessory antennas for receiving the radio signal;
a reception time measurement unit that measures a reception time of a first reference signal of the radio signal received via the primary antenna;
a relative angle measurement unit that measures the phase of the second reference signal of the radio signal received via the basic antenna and the accessory antenna and determines the relative angle between the movable body and a user of the movable body from the reception phase difference between the basic antenna and the accessory antenna;
a transmission data creation unit that generates measurement data including a reception time of the first reference signal transmitted via the basic antenna and a relative angle between the movable object safety device and the user safety device;
a movable body safety device control unit that controls the basic antenna, the accessory antenna, the reception time measurement unit, the relative angle measurement unit, and the transmission data creation unit,
The user safety device comprises:
a basic antenna for transmitting and receiving the radio signal;
a transmission data generation unit that generates the first reference signal, the second reference signal, and data including transmission time information of the first reference signal via the basic antenna;
a measurement data detection unit that detects the measurement data transmitted from the movable body safety device via the basic antenna;
a user protection device for protecting a user of the movable body;
a driver for driving the user protection device;
a distance conversion means for converting a transmission time of the first reference signal transmitted by the user safety device and a reception time of the first reference signal detected by the measurement data detection unit into a distance between the movable body and a user of the movable body;
an orthogonal coordinate conversion means for converting polar coordinates having the movable body safety device as the origin, which are indicated by the relative angle detected by the measurement data detection unit and the distance converted by the distance conversion means, into orthogonal coordinates having the movable body safety device as the origin between the movable body and the movable body user;
a user safety device control unit including a timing unit that determines a drive timing of the driver by referring to the orthogonal coordinates of the movable body and the movable body user converted by the orthogonal coordinate conversion unit;
A safety system comprising: The user safety device control unit
a motion vector generating means for generating a motion vector based on a difference between the current orthogonal coordinates generated by the orthogonal coordinate conversion means and the immediately previous orthogonal coordinates;
2. The safety system according to claim 1, wherein the timing means determines the timing of the driver's movement by referring to the orthogonal coordinates and the motion vector. The user safety device control unit
a coordinate prediction means for determining predicted orthogonal coordinates after a predetermined time from the motion vector generated by the motion vector generation means and the orthogonal coordinates;
3. The safety system according to claim 2, wherein the timing means determines the timing of the driver's drive by referring to the orthogonal coordinates and the predicted orthogonal coordinates. The user safety device control unit
a predicted polar coordinate conversion means for converting the predicted rectangular coordinates of the coordinate prediction means into predicted polar coordinates represented by a distance and an angle from an origin;
an alternative orthogonal coordinate generating means for generating alternative orthogonal coordinates by converting the polar coordinates into orthogonal coordinates by replacing a distance portion from the origin of the predicted polar coordinates with the distance between the movable body and the movable body user obtained by the distance converting means;
4. The safety system according to claim 3, further comprising a coordinate selection means for replacing the orthogonal coordinates input to the timing means with the alternative orthogonal coordinates by referring to the relative angle obtained by the relative angle measurement unit. A safety system including a plurality of movable body safety devices each having an antenna attached to a movable body and a user safety device each having an antenna attached to a user of the movable body, the system performing wideband wireless communication between the movable body safety devices and the user safety devices,
the wireless signal between the movable object safety device and the user safety device includes a first reference signal having multiple harmonic components for measuring a reception time ;
Each of the movable body safety devices is
a first basic antenna for transmitting and receiving the radio signal;
a reception time measurement unit that measures a reception time of a first reference signal of the radio signal received via the first basic antenna;
a transmission data creation unit that generates data including a reception time of the first reference signal transmitted via the first basic antenna; and a movable body safety device control unit that controls the first basic antenna, the reception time measurement unit, and the transmission data creation unit,
The user safety device comprises:
a second basic antenna for transmitting and receiving the radio signal;
a transmission data generation unit that generates the first reference signal and data including transmission time information of the first reference signal via the second basic antenna;
a measurement data detection unit that detects a reception time of the first reference signal transmitted from each of the movable body safety devices via the second basic antenna;
a user protection device for protecting a user of the movable body;
a driver for driving the user protection device;
a distance conversion means for converting a transmission time of the first reference signal transmitted by the user safety device and a reception time of the first reference signal received by each of the movable body safety devices into a distance between each of the movable body safety devices and a user of the movable body;
a movable body safety device coordinate registration means for registering in advance coordinates of the movable body safety device located at the center of each of the movable body safety devices attached to the movable body as the origin ;
a coordinate conversion means for converting the distances between the movable body safety devices and the users of the movable body converted by the distance conversion means and the coordinates of the movable body safety devices registered by the movable body safety device coordinate registration means into relative coordinates between the movable body and the users of the movable body;
a user safety device control unit including a timing unit that determines a drive timing of the driver by referring to the relative coordinates of the movable body and the user of the movable body that have been converted by the coordinate conversion unit;
A safety system comprising: The user safety device control unit
a motion vector generating means for generating a motion vector based on a difference between the current orthogonal coordinates generated by the coordinate conversion means and the immediately previous orthogonal coordinates;
6. The safety system according to claim 5, wherein the timing means determines the timing of the driver's movement by referring to the orthogonal coordinates and the motion vector. The user safety device control unit
a coordinate prediction means for calculating predicted orthogonal coordinates after a predetermined time from the motion vector generated by the motion vector generation means and the orthogonal coordinates;
7. The safety system according to claim 6, wherein the timing means determines the timing of the driver's drive by referring to the orthogonal coordinates and the predicted orthogonal coordinates.