JPH0592769U - Inter-vehicle distance alarm device - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the occurrence of undetectable areas and erroneous detection due to changes in vehicle speed. [Structure] Antennas 11, 12, 13 for radiating a plurality of radar beams in front of a vehicle, respectively, and a transceiver 1 for outputting a start signal to the antenna and receiving a received signal.
4, 15, 16, detection distance setting means 21 for setting a detection distance, signal processing means 22 for outputting a detection signal according to an obstacle in the detection area, vehicle speed sensor 18 for outputting vehicle speed information, and vehicle The yaw rate sensor 19 for outputting the yaw rate information of the vehicle and the turning radius calculation means 20 for calculating the turning radius of the vehicle are provided, and the detection distance setting means 21 sets the detection distance B of each radar beam on the anti-turning side based on the turning radius. The detection distance of the radar beam is set shorter, and the detection distance of the turning radar beam is set longer.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a device that emits a radar beam in front of a vehicle to detect an obstacle, and more particularly, to an inter-vehicle distance warning device that divides each of a plurality of radar beams into right and left and emits them to detect an obstacle.

[0002]

[Prior Art]

 Conventionally, an inter-vehicle distance warning device mounted on a vehicle radiates a radar beam, which is a detection wave, to an obstacle such as a vehicle or a guide rail in front of a traveling road, and this radar beam reflects the reflected wave when it hits an obstacle. Is received and the presence or absence of an obstacle is determined based on the output according to the difference between the frequencies of the transmitted wave and the received wave. An example of such a device is disclosed in Japanese Patent Publication No. 60-34708. This device scans a radar beam horizontally from a scanning antenna 2 mounted on a vehicle 1 as shown in FIG. 8 and spreads the beam in detection areas E 1, E 2 and E 3 which respectively spread in 3 directions as shown by a chain double-dashed line. It is radiating. In this case, the scanning antenna 2 is configured to sequentially change the beam direction by mechanical scanning or electrical scanning and radiate the beam to each of detection areas E1, E2, E3 which spread in three directions.

If there are obstacles C (other vehicles), G (guard rails), etc., the beam as the detection wave radiated as described above is delayed by the delay according to the distance to each obstacle and the like and is reflected. As received. For example, when the received wave is received within a predetermined reception time (in the case of pulse radar), or when the received wave is received, the difference between the frequencies of the transmitted and received waves is calculated (in the case of FM-CW radar). When the beat outputs are obtained, the signal processor 3 is configured to issue a predetermined alarm command based on these outputs.

Here, in particular, the turning angle (steering turning angle) θs of the steering wheel is taken in by the attitude detector 4, and the information on the straight-ahead or left-right turning direction of the vehicle is taken in the signal processor 3. Thereby, the signal processor 3 removes the reflected wave (detection signal) for a certain time or longer by using the time gate preset for the reflected wave of each detection area E1, E2, E3, or A reflected wave (detection signal) with a certain frequency or higher is removed by using a preset filter for the reflected wave of each detection area E1, E2, E3 to detect each detection area (detection area of each beam). The detection signal is removed from the area outside the range (range cut). By such range cut processing, the obstacles C and G in the non-detection areas e1, e2, and e3, which are areas outside the area (area E1 in FIG. 8) opposite to the curving direction when the vehicle 1 travels in a curve. It eliminates the inconvenience of erroneously determining that an obstacle in the traveling direction and outputting a detection signal.

[0005]

[Problems to be solved by the device]

 Here, when the range cut processing is performed based on the information on the straight traveling direction and the right-and-left bending direction of the vehicle obtained by the steering turning angle θs, the following problems occur. That is, it is assumed that the turning radius at an extremely low speed is obtained according to the steering angle θs, and the detection distance for the range cut processing is set uniformly for each detection region according to the turning radius. Then, even if the steering angle θs is the same, the amount of side slip of the tire increases, so that the turning radius Ra at the low speed shown in FIG. 9 (a) becomes higher than that at the high speed shown in FIG. 9 (b). The turning radius Rb becomes large. Therefore, the detection distances of the detection areas a1, a2, a3 at the time of low speed shown in FIG. 9 (a) are relatively proper values, and the non-detection areas e1, e2, e3 are also proper. On the other hand, the detection areas a1, a2, a3 at the time of high speed shown in FIG. 9 (b) are too short, and the undetectable areas b1, b2, b3 which should originally be the detection areas are expanded. In this way, in the range cut processing by setting the detection area according to the steering angle θs, the non-detection areas b1, b2, b3 are widened at high speed, and the function of the inter-vehicle distance warning device cannot be fully exerted. Is made.

Further, the driver does not always keep the steering wheel at a constant angle when passing through one curve, and the steering angle θs changes frequently. Therefore, if the range cut distance (detection distance) is determined according to the steering angle θs, an erroneous alarm is likely to be issued, which is also a problem. An object of the present invention is to provide an inter-vehicle distance warning device that can prevent the occurrence of an undetectable area and erroneous detection due to changes in vehicle speed.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides an antenna that radiates a plurality of radar beams whose emission directions are divided into left and right, respectively, in front of a vehicle, and a transceiver that outputs a start signal to the antenna and receives a received signal. Machine, detection distance setting means for setting a detection distance according to the detection area of the obstacle, and a signal for calculating and outputting a detection signal according to the obstacle within the detection area based on the start signal and the reception signal It has a processing means, a vehicle speed sensor for outputting the vehicle speed information of the vehicle, a yaw rate sensor for outputting the yaw rate information of the vehicle, and a turning radius calculation means for calculating the turning radius of the vehicle based on the vehicle speed and the yaw rate. However, the detection distance setting means sets the detection distance of each radar beam based on the turning radius to be shorter as the detection distance of the anti-turning side radar beam, And sets as the detection distance of the beam long.

[0008]

[Action]

 The vehicle speed sensor outputs vehicle speed information, the yaw rate sensor outputs yaw rate information, the turning radius calculation means calculates the turning radius of the vehicle based on the vehicle speed and yaw rate, and the detection distance setting means determines the radar beam of each radar beam based on the turning radius. Since the detection distance is set shorter for the radar beam on the anti-turning side and longer for the radar beam on the turning side, the signal processing means uses the detection signal corresponding to the obstacle in the detection area as the start signal. When calculating and outputting based on the received signal, it is possible to eliminate unnecessary detection signals from obstacles in the detection area on the anti-turning side, which is easily deviated from the traveling direction.

[0009]

【Example】

 The inter-vehicle distance warning device of FIG. 1 is attached to the front end of the vehicle 10 and outputs first and second pulse antennas 11, 12, and 13, and transmission antennas 111, 121, 131 of the respective antennas. The first, second, and third transmitters / receivers 14, 15, 16 receiving the received waves by the reception antennas 112, 122, 132 and the reception by the receivers 14, 15, 16 A controller 17 capable of receiving a wave and determining whether an obstacle is present and outputting a detection signal Se, a vehicle speed sensor 18 outputting the vehicle speed Vc information of the vehicle 10 to the controller 17, and a displacement angle of the traveling direction of the vehicle 10 The yaw rate sensor 19 outputs a yaw rate (° / sec) as a time ratio of a certain yaw angle α (see FIG. 2) to the controller 17.

Here, the first, second and third transmitting antennas 111, 121 and 131 are controlled by the first, second and third transceivers 14, 15 and 16 to have a predetermined time width tb (see FIG. 5 (c)), pulses p1, p2, p3 (see FIGS. 5A, 5B, and 5C), which are transmission waves, are sequentially emitted. The first, second and third receiving antennas 112, 122 and 132 are controlled by the first, second and third transceivers 14, 15 and 16 to receive a received pulse pr (Fig. 5 (a)). , (B), (c)) are sequentially emitted.

Here, the second transmission antenna 121 emits a pulse p2 to the detection area A2 within a predetermined angle in the direction of the vehicle body centerline in plan view, and the first transmission antenna 111 has the detection area in plan view. The pulse p1 is emitted to the detection area A1 in the left proximity area of A2, and the third transmission antenna 131 emits the pulse p3 to the detection area A3 in the right proximity area of the detection area A2 in plan view.

Here, the controller 17 has functions as a turning radius calculation means 20, a detection distance setting means 21, and a signal processing means 22, which will be described later. Each of the transceivers 14, 15 and 16 has the same configuration, and a well-known oscillator (not shown) for causing the transmission antennas 111, 121 and 131 to radiate the pulses p1, p2 and p3 having a predetermined width is connected. A well-known amplifier (not shown) that amplifies and outputs each reception pulse pr is connected to each of the first, second, and third reception antennas 112, 122, and 132. The oscillation signal of each oscillator and the reception pulse pr which is the output of the amplifier are output to the signal processing means 22 of the controller 17.

As shown in FIG. 2, the yaw rate sensor 19 sequentially detects yaw angle α information, which is a change angle of the center line Lc of the vehicle body in a plan view, from the movement of an inertial body (not shown), and the yaw angle α A timer and an arithmetic circuit for calculating a change in unit time, that is, a time ratio as a yaw rate γ (° / sec) are provided. And outputs it to the controller 17. Here, the change of the yaw angle α is provided by a yaw rate sensor 19 not shown. The yaw rate γ and the vehicle speed Vc are taken into the turning radius calculation means 20. The turning radius calculation means 20 calculates the yaw rate γ by the following equation (1).

R = V / (γ × π / 180) (1) Note that the turning radius is R (m) and the vehicle speed is V (m / sec). Since the turning radius R (m) obtained by the equation (1) is proportional to the vehicle speed Vc and inversely proportional to the yaw rate γ, it is possible to consider the increase in the turning radius due to the tire slip accompanying the vehicle speed increase as described above. It will be.

In consideration of the equation (1), a turning radius map (see FIG. 3) for calculating the turning radius R of the vehicle from the yaw rate γ and the vehicle speed Vc is prepared in advance, and the turning radius R is calculated based on the map. It may be calculated. It should be noted that this turning radius map differs depending on the driving characteristics of each vehicle, and a map manufactured in advance for each vehicle is adopted. The detection distance setting means 21 of the controller sets the detection distances B1, B2, B3 for each of the first, second and third detection areas A1, A2, A3 based on the turning radius R. In particular, the detection distance of the detection area on the side opposite to the turning direction on the side opposite to the turning direction is set shorter, and the detection distance on the side of the turning side in the turning direction is set longer. Considering such characteristics, the detection distance calculation map as shown in FIG. 4 is set. Here, in the case of a right turn, the detection distances of the detection areas A1, A2, A3 are set so that each value increases with an increase in the right turn amount while keeping B1 <B2 <B3. In the case of a left turn, the detection distances of the detection areas A1, A2, A3 are set so that the respective values increase with an increase in the left turn amount while keeping B1> B2> B3.

The signal processing means 22 of the controller outputs the detection signals Se corresponding to the obstacles within the detection distances B1, B2, B3 corresponding to the detection areas A1, A2, A3 to the pulses p1, p2, p3 (starting). Signal) and each received pulse pr (received signal), and calculates and outputs. That is, the signal processing means 22 of the controller sequentially calculates the detection times tf1, tf2, tf3 corresponding to the respective detection distances B1, B2, B3. The detection distance B in the pulse radar is proportional to the detection time tf, and if the proportionality constant is k1, then equation (2) is obtained.

B = k1 × tf (2) Therefore, each pulse p 1, p 2, p 3 from each of the first, second and third transceivers 14, 15, 16 is It is determined whether or not there is a received pulse pr to be input until the detection time tf1, tf2, tf3 elapses from the rising time. When the reception pulse pr is input, the detection signal Se is output to the alarm means and vehicle speed regulation means (not shown). Here, the inter-vehicle distance warning control process performed by the controller 17 will be described with reference to the inter-vehicle distance warning control routine of FIG.

When the control is started, step s1 is reached, where it is determined whether or not the vehicle speed Vc exceeds a vehicle speed 30 (Km / h) as a threshold value for determining whether or not the system operation range is set, and the vehicle speed Vc is lower than the threshold value. While returning, return to step s2. Here, the latest yaw rate γ is fetched, and it is judged whether or not this value is 0. If it is 0 (straight ahead), return is made, and if not straight ahead, the routine proceeds to step s3. In step s3, the turning radius R is calculated from the vehicle speed Vc and the yaw rate γ according to the equation (1), and the detection distance (range cut distance) is calculated from the turning radius R. Then, the detection times tf1, tf2, tf3 corresponding to the detection distances B1, B2, B3 are sequentially calculated. After that, the process proceeds to step s4, where each pulse p1, p2, p3 (starting signal) from each of the first, second and third transceivers 14, 15, 16 is time-filtered, that is, each transceiver 14 , 15 and 16 are detected during the detection time tf1, tf2, tf3 from the rise of each pulse p1, p2, p3, and only the input received pulse pr (received signal) is regarded as the detection signal Se and output. , Return.

As described above, the time filter outputs the detection signal Se based on the received pulse pr input within the detection times tf1, tf2, and tf3 (see FIG. 5A), and the detection times tf1, tf2, and tf3. After that, that is, the received pulse pr (received signal) out of the time filter is eliminated, and erroneous detection due to an obstacle in the anti-turning direction different from the traveling direction can be eliminated. In particular, the turning radius R is calculated from the vehicle speed Vc and the yaw rate γ, and the detection times tf1, tf2, tf3 corresponding to the detection distance (range cut distance) are calculated from the turning radius R, and the time filter based on this is applied. Since an accurate detection distance (range cut distance) can be secured, it is possible to prevent the occurrence of an undetectable area (see Fig. 9 (b)), and the yaw rate γ, which has less fluctuation than the steering angle θs, is used. Therefore, it is possible to reduce false detection due to changes in vehicle speed.

In the above description, the inter-vehicle distance warning device of FIG. 1 detects an obstacle by a pulse radar, but instead of this, a frequency modulation (FM-CW) radar may be used. The inter-vehicle distance warning device in this case includes many of the same members as the device of FIG. 1, and a duplicate description is omitted here. That is, the transmitters / receivers 14, 15 and 16 of the apparatus of FIG. 1 are replaced with those of the well-known FM-CW radar, and the control of the signal processing means 22 in the controller 17 (the control flow is shown in FIG. 7) is used. Only the difference.

The signal processing means (see FIG. 1) of the controller 17 detects the beat output of the difference Δf (= fh−fr) between the transmission wave frequency fh and the reception wave frequency fr, and amplifies the beat output at the time of detection. It is output as the detection signal Se. In this case, in particular, the detection frequencies (frequency filters) f1, f2, f3 corresponding to the detection distances B1, B2, B3 are sequentially calculated. The detection frequency fn in the FM-CW radar is proportional to the detection distance B, and if the relative constant is k2, it becomes as shown in equation (3).

B = k2 × fn (3) Therefore, the transmission frequency fh and the reception frequency fr from the first, second and third transceivers 14, 15 and 16 respectively. When a beat output having a difference Δf (= fh-fr) is detected, it is amplified, and if it is within each of the detection frequencies (frequency filters) f1, f2, f3, an alarm means not shown as a detection signal Se is shown. And the vehicle speed regulation means. Here, the inter-vehicle distance warning control processing performed by the controller 17 will be described with reference to the inter-vehicle distance warning control routine of FIG. 7. Note that duplicate description of the same routine as that shown in FIG. 6 will be simplified.

When the control is started, step s1 is reached, and unless the vehicle speed Vc is 30 (Km / h) or less, step s2 is proceeded to. Here, unless the yaw rate γ is 0, the process proceeds to step s3. In step s3 ', the vehicle speed Vc, the turning radius R corresponding to the yaw rate γ, and the detection distances B1, B2, B3 corresponding to the turning radius R are calculated. Then, the respective detection frequencies (frequency filters) f1, f2, tf3 corresponding to the detection distances B1, B2, B3 are sequentially calculated. After this, the process proceeds to step s4 'to perform range cut. That is, when the beat output of the difference Δf (= fh−fr) between the transmission frequencies fh and the reception frequencies fr from the first, second and third transceivers 14, 15, 16 is detected, If this is amplified and is within each of the detection frequencies (frequency filters) f1, f2, f3, this is regarded as the detection signal Se and output, and the process returns.

As described above, since the detection signal Se is output by the frequency filter based on the reception wave fr input within the detection frequencies f1, f2, and f3, the reception wave (reception signal) of the reception frequency that has deviated from the frequency filter is Therefore, false detection due to an obstacle in the anti-turning direction, which is different from the traveling direction, can be eliminated. In particular, the turning radius R is calculated from the vehicle speed Vc and the yaw rate γ, and the respective detection frequencies f1, f2, f3 corresponding to the detection distance (range cut distance) are calculated from the turning radius R, and the frequency filter based on this is applied. Since a proper detection distance (range cut distance) can be secured, the occurrence of a non-detectable area (see FIG. 9 (b)) can be prevented, and since the yaw rate γ that has less fluctuation than the steering angle θs is used, False detection due to changes in vehicle speed can be reduced.

[0025]

[Effect of the device]

 As described above, the present invention calculates the turning radius of the vehicle based on the vehicle speed and the yaw rate, and sets the detection distance of each radar beam based on the turning radius as short as the detection distance of the anti-turning side radar beam. Since the detection distance of the beam is set to be longer, the detection signal corresponding to the obstacle in the detection area is calculated based on the start signal and the received signal and is output. Unnecessary detection signals from obstacles can be eliminated, and in particular, generation of undetectable areas due to changes in vehicle speed and erroneous detection can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an inter-vehicle distance warning device as one embodiment of the present invention.

FIG. 2 is an explanatory view of the posture of an automobile equipped with the device of FIG.

3 is a three-dimensional characteristic diagram of a turning radius calculation map that can be adopted by the controller of the apparatus of FIG.

FIG. 4 is a characteristic diagram of a detection distance calculation map used by the controller of the apparatus of FIG.

5A is a waveform diagram for explaining the operation of the device in FIG. 1 in a first transceiver, and FIG. 5B is a waveform diagram for explaining the operation of the device in FIG. 1 in a second transceiver. FIG. 3C is a waveform diagram for explaining the operation of the device of FIG. 1 in the third transceiver.

FIG. 6 is a control flowchart of the apparatus of FIG.

FIG. 7 is a control flowchart of an inter-vehicle distance warning device according to another embodiment of the present invention.

FIG. 8 is a schematic configuration diagram of a conventional device.

FIG. 9A is an explanatory view of the operation of the conventional device at low speed. (B) It is operation | movement explanatory drawing at the time of the high speed of the conventional apparatus.

[Explanation of symbols]

 10 Car 11 Transceiver 12 Transceiver 13 Transceiver 14 Transceiver 15 Transceiver 16 Transceiver 17 Controller 18 Vehicle speed sensor 19 Yaw rate sensor 20 Turning radius calculating means 21 Detecting distance calculating means 22 Signal processing means B Detecting distance R Turning radius γ Yaw rate

Claims (1)

[Scope of utility model registration request] 1. An antenna for radiating a plurality of radar beams whose emission directions are divided into left and right in front of a vehicle, respectively.
A transmitter / receiver that outputs a start signal to the antenna and receives a received signal, a detection distance setting unit that sets a detection distance according to an obstacle detection area, and a detection signal that corresponds to an obstacle in the detection area Signal processing means for calculating and outputting based on a start signal and a received signal, a vehicle speed sensor for outputting vehicle speed information of the vehicle, a yaw rate sensor for outputting yaw rate information of the vehicle, and a vehicle speed based on the vehicle speed and yaw rate of the vehicle. And a turning radius calculation means for calculating a turning radius, wherein the detection distance setting means sets the detection distance of each of the radar beams based on the turning radius to be shorter than the detection distance of the anti-turning side radar beam. An inter-vehicle distance warning device characterized in that the detection distance of the beam is set longer.