JPH06230125A - On-board ultrasonic measuring device - Google Patents

Abstract

PURPOSE:To enable detecting vehicle conditions other than car speed by synthesizing, using calculation means, speed vector obtained with the first ultrasonic wave transmitter/receiver and the second and third ones as well. CONSTITUTION:An ultrasonic wave transmitter/receiver TR1, attached to a vehicle 100, sends ultrasonic wave vibration, with a specified ultrasonic wave beam width, toward a road surface, and receives the reflected waves, so that speed vector V1 parallel to advancing direction of the vehicle 100 is obtained. Ultrasonic wave transmitter/receivers TR2 and TR3 have the same characteristics as the TR1, and send ultrasonic waves with a specified ultrasonic wave beam width toward the road surface, and receive the reflected waves, for obtaining speed vectors V2 and V3, respectively. With the TR1, the speed vector V1 in the advancing direction of vehicle 100, or car speed or acceleration, is detected, and with the TR2 and TR3, speed vectors V2 and V3, respectively, in the specified directions are obtained, and then they are synthesized for obtaining speed or acceleration of the components, in the advancing direction and the one vertical to it, of the vehicle 100, and a yaw angle and a yaw rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a measurement device that uses various speed information such as a navigation system, a vehicle speed detection device, a skid prevention device, an ABS device, a suspension device, a centrifugal force detection device, a yaw angle and a yaw rate detection device, and in particular, an ultrasonic wave loaded on a vehicle. The present invention relates to a vehicle-mounted ultrasonic measuring device.

[0002]

2. Description of the Related Art As a velocity measuring device using ultrasonic waves of this type, there is a technique disclosed in Japanese Utility Model Laid-Open No. 57-68574. The technology disclosed in this publication continuously transmits ultrasonic waves from a separate wave transmitter, continuously receives the waves received by reflecting from the reflector, and calculates the difference between the waves transmitted and received. It is for detecting the Doppler frequency and is a well-known technique at present.

Further, as a velocity measuring device using this kind of ultrasonic wave, there is a technique disclosed in JP-A-59-203973. The technique disclosed in this publication has a wave transmitter and a wave receiver which are separate bodies, as in the case of the above-mentioned publication, and in particular, the number of wave receivers is two, and vertical vibration of the vehicle body, nose up, This is to reduce the error due to nose down.

As a speed measuring device using this kind of ultrasonic wave, there is a technique disclosed in Japanese Patent Laid-Open No. 58-39971. The technology disclosed in this publication transmits ultrasonic waves in a pulse shape, opens a reception gate corresponding to the pulse width at the time of reflection and reception, and measures the time of a predetermined wavelength of the received wave. , The Doppler shift amount is obtained and the vehicle speed is measured.

Further, as a vehicle-mounted ultrasonic measuring device of this type, there is a technique disclosed in Japanese Patent Laid-Open No. 3-269388.

In this technique, ultrasonic waves are radiated from a wave transmitter / receiver on a road surface in the front or front direction of a vehicle at a predetermined depression angle, and from the received signals of the radiated ultrasonic waves and the reflected waves of the projections on the road surface to the projections. Is measured, and the signal level of the reflected wave of the road surface projection is compared with a predetermined threshold value to detect the presence and size of the road surface projection in front of the vehicle. Then, the vehicle height is detected from the straight line distance and the emission angle of the ultrasonic wave when the reflected wave returns from the road surface, and the vehicle speed is detected based on the obtained Doppler frequency.

That is, as shown in the operational principle diagram of FIG. 9 in which one ultrasonic wave transmitter / receiver TR of the on-vehicle ultrasonic wave measuring device transmits and receives, ultrasonic waves are radiated to reach the road surface. Letting L [m] be the distance up to, H [m] be its height, and φ be its emission angle, then L = H / sin φ (1)

Loss due to propagation distance at this time Loos
Is Loos = (diffusion loss) + (propagation loss) = 20 · log (2 · L) + 2 · L · α [dB] ··· (2) where α: damping constant, for example, α100KHz = 2.1 [DB / m] α200KHz = 8.5 [dB / m]

On the other hand, when the ultrasonic beam width θ is narrowed, the energy is concentrated in the transmitted wave, so that the signal component S increases. Moreover, the S / N for the isotropic noise is improved in the received wave.

The total transmission / reception gain G is G = (transmission gain) × (reception gain) = {10 · log (γ / θ ² )} × 2 (3) where γ Is γ = 3.4 × 1 if the beam is rotationally symmetric
It is 0 ⁴ .

In the operating principle diagram of the on-vehicle ultrasonic measuring device shown in FIG. 9, an ultrasonic wave having a frequency f [Hz] is intermittently radiated to the road surface, and the received frequency fo = f−df [Hz]. The Doppler frequency df [Hz] is calculated from df = 2f (V / 3.6) cosφ / C [Hz] ··· (4) where V: vehicle speed [Km / h] C: sound speed It becomes [m / s].

Particularly, in the technique disclosed in the above publication, ultrasonic waves are radiated with an equal radiation angle in the front-back direction of the vehicle body, and the Doppler frequency of the received signal of each reflected wave is detected,
By obtaining the Doppler frequency of the difference, the vehicle speed at which the vertical speed component of the vehicle body is canceled is detected. Also, only the vertical component is detected and used as the vehicle height.

In this way, the protrusions and the like on the front road surface during traveling of the vehicle are detected using the ultrasonic waves, and the vehicle height and vehicle speed are also detected.

[0014]

However, in the technique disclosed in the above publication, the vehicle height is detected from the straight line distance and the emission angle of the ultrasonic wave when the reflected wave returns from the road surface, and the obtained Doppler frequency is calculated. Based on the detected vehicle speed, or ultrasonic waves are emitted with an equal radiation angle in the longitudinal direction of the vehicle body, the Doppler frequency of the received signal of each reflected wave is detected, and the Doppler frequency of the difference is calculated. Thus, the vehicle speed at which the vertical speed component of the vehicle body is canceled is detected.

However, although the vehicle-mounted ultrasonic measuring device for measuring the movement of the vehicle by using this kind of ultrasonic wave can measure the vehicle speed, the vehicle height, etc., it also measures the vehicle speed component. However, its use was limited to vehicle speed and vehicle height.

Therefore, it is an object of the present invention to provide a vehicle-mounted ultrasonic measuring device capable of detecting the state of the vehicle other than the vehicle speed by using ultrasonic waves.

[0017]

SUMMARY OF THE INVENTION An in-vehicle ultrasonic measuring device according to the present invention transmits ultrasonic waves in parallel with a traveling direction of a vehicle with a predetermined depression angle gradient with respect to a road surface, and reflects the ultrasonic waves. With respect to a straight line parallel to the traveling direction of the vehicle of the first ultrasonic wave transceiver,
Two second ultrasonic wave transmitters / receivers and a third ultrasonic wave transmitter / receiver, which are separated from each other by an equal angle and transmit ultrasonic waves with a predetermined depression angle to the road surface and receive the reflected waves. The two-dimensional velocity of the vehicle is calculated by the calculating means by synthesizing the velocity vectors obtained by the above.

[0018]

According to the present invention, the speed in the traveling direction of the vehicle, that is, the vehicle speed or acceleration is detected by the first ultrasonic wave transmitter / receiver, and is specified by the second ultrasonic wave transmitter / receiver and the third ultrasonic wave transmitter / receiver. The velocities in the directions are obtained, and these are vector-synthesized to obtain the traveling direction of the vehicle and the component velocity or acceleration, the yaw angle, and the yaw rate perpendicular to the traveling direction of the vehicle.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An on-vehicle ultrasonic measuring device according to an embodiment of the present invention will be described below.

<Basic Principle> FIG. 1 is an explanatory view of the basic principle of the ultrasonic measuring device for vehicle according to the embodiment of the present invention.

In FIG. 1, the vehicle 10 is parallel to the traveling direction of the vehicle 100 and has a depression angle of 45 degrees with respect to a horizontal plane.
The ultrasonic transmitter / receiver TR1 attached to 0 is 200 [KHz]
The ultrasonic vibration of is transmitted to the road surface with a predetermined ultrasonic beam width,
The reflected wave is received, and a velocity vector V1 parallel to the traveling direction of the vehicle 100 is obtained. Specifically, the ultrasonic wave transmitter / receiver TR1 is disposed in the front center of the vehicle 100. The ultrasonic wave transmitter / receiver TR2 has the same characteristics as the ultrasonic wave transmitter / receiver TR1, transmits ultrasonic waves to the road surface with a predetermined ultrasonic beam width, and receives the reflected waves thereof. As shown in a), the ultrasonic transducer TR1 arranged in parallel with the traveling direction of the vehicle 100.
Is arranged at a position displaced by an angle of 180-δ degrees with respect to a straight line parallel to the traveling direction of the vehicle, and obtains a velocity vector V2. Similarly, the ultrasonic wave transmitter / receiver TR3 has the same characteristics as the ultrasonic wave transmitter / receiver TR1, transmits ultrasonic waves to the road surface with a predetermined ultrasonic beam width, and receives the reflected waves thereof. 18 along the straight line parallel to the traveling direction of the vehicle of the ultrasonic transducer TR1 arranged parallel to the traveling direction of the vehicle 100.
It is arranged at a position angularly displaced in the opposite direction of 0-δ degrees and obtains the velocity vector V3. These ultrasonic wave transmitter / receiver TR1, ultrasonic wave transmitter / receiver TR2, ultrasonic wave transmitter / receiver TR
3 is molded into each base member B made of synthetic resin as a mounting base, and integrated with each other. And FIG.
As shown in (b), the base member B is attached to the lower surface of the vehicle 100. The wheel width of the vehicle 100 of this embodiment is L [m].

Here, as the two-dimensional speed of the vehicle 100,
When the velocity vector Vx parallel to the traveling direction and the velocity vector Vy in the vertical direction (horizontal direction) are vector-synthesized, for example, the velocity vector Vx parallel to the traveling direction of the vehicle 100 is: velocity vector Vx = V1. (5) The velocity vector Vy of the lateral velocity of the vehicle 100 is velocity vector Vy = (V2-V3) / (2.sin?) (6) The yaw rate ω of the vehicle 100 is ω = (V2−V3) / L · cos δ (7)

Similarly, the distance and the acceleration can be calculated by integrating and differentiating the velocity vector.

<Circuit Configuration of the Embodiment> FIG. 2 is a circuit configuration diagram of an in-vehicle ultrasonic measuring device according to an embodiment of the present invention.

In FIG. 2, a microcomputer 1 having an A / D converter of 8ch inside is a known one having a RAM and a ROM and an arithmetic unit necessary for arithmetic control, and its internal function. The description will be given later. The ultrasonic wave transmitter / receiver TR1 transmits and receives ultrasonic waves of 200 [KHz] with a predetermined ultrasonic beam width. Further, the transmission / reception switching circuit 3 performs switching when outputting or receiving ultrasonic vibration from the ultrasonic wave transceiver TR1. Further, in the transmission / reception switching circuit 3, when the Zener diode ZD1 is turned on, the Zener diode ZD2 is turned on via the capacitor C1 and a signal is output from the ultrasonic transducer TR1. When the Zener diode ZD1 is turned off, the signal becomes small. Zener diode ZD2
Is turned off, and a signal is output to the preamplifier 4 via the series resonance circuit of the capacitor C1 and the coil L1.

Zener diode ZD of transmission / reception switching circuit 3
1 is connected in series to the secondary side of the transformer 5, and the primary side of the transformer 5 is connected by a switching transistor 6 so as to supply power. The switching transistor 6 has a rectangular wave of 100 [KH by the output of the frequency dividing circuit 7 to which the external oscillation frequency output of 10 [MHz] is input.
z] is input and the switching transistor 6 is opened and closed intermittently with a signal of 100 [KHz].

Therefore, when the microcomputer 1 sets the intermittent output P1 to "1", the output of the frequency dividing circuit 7 turns the switching transistor 6 on and off, and the secondary side of the transformer 5 has a high voltage of 200 [. KHz] is generated, which causes the ultrasonic transducer TR1 to generate ultrasonic waves.

The signal from the ultrasonic wave transceiver TR1 detected through the transmission / reception switching circuit 3 is amplified by the preamplifier 4 and the bandpass filter 8 corresponding to the speed change such as the vehicle speed.
Only the reflection of the ultrasonic wave radiated via is detected, which is further amplified by the amplifier 9 and input to the comparator 10 to be binarized. A part of the input of the comparator 10 is input to the reception level detection circuit 11 and is input to the A / D converter of the microcomputer 1.

The output signal of the comparator 10 is input to the frequency detecting PLL circuit 12, and the number of repetitive pulses proportional to the output of the comparator 10 is output as its output signal.

More specifically, since the output of the comparator 10 is very low and has a frequency of about several tens [KHz], it can be used as a vehicle speed and a circuit that multiplies the frequency in order to obtain resolution that can be obtained in a short time. Is used as. Further, since the output of the comparator 10 has meaning only during the time when the receiving gate is open, the frequency is sampled and held by the time signal during that time. PL when receiving gate is closed and not valid
The function as the L circuit is stopped, and the sampled and held voltage is held.

Specifically, a pulse obtained by dividing the output by a factor of 8 and the output of the comparator 10 are compared by the phase difference detection circuit PD, and the phase difference is guided to the analog switching circuit AS via the low pass filter LPF. , Its output is input to the resistor R and the capacitor C for sampling and holding, and is also input to the microcomputer 1 via the voltage controlled oscillation circuit VCO. Voltage controlled oscillator VCO
Is output to the phase difference detection circuit PD via the frequency dividing circuit DEM which divides the frequency by 1/8. As a result, the pulse repetition frequency multiplied by 8 is input to the microcomputer 1 from the voltage controlled oscillator circuit VCO.

The outside air temperature is detected by the thermistor 15 and input to the terminal of the A / D converter incorporated in the microcomputer 1.

This type of ultrasonic wave transmitter / receiver TR1, a transmission / reception switching circuit 3, a transformer 5, a switching transistor 6 and a frequency dividing circuit 7, and a transmission circuit system for transmitting an ultrasonic wave, an ultrasonic wave transmitter / receiver TR1, and a transmitter / receiver. The ultrasonic transmission / reception circuit 20TR includes a switching circuit 3, a preamplifier 4, a bandpass filter 8, an amplifier 9, a comparator 10, a reception level detection circuit 11, and a frequency detection PLL circuit 12, and a reception circuit system that receives ultrasonic waves. Are configured.

The ultrasonic transmission / reception circuit 30TR using the other ultrasonic transmission / reception device TR2 and the ultrasonic transmission / reception circuit 40TR using the ultrasonic transmission / reception device TR3 also have the same circuit configuration. It should be noted that the description of the specific circuit configuration is duplicated, and the description thereof is omitted.

FIG. 3 is a functional configuration diagram of the microcomputer 1 used in the circuit configuration of the vehicle-mounted ultrasonic measuring device according to the embodiment of the present invention.

In FIG. 3, a main operation control circuit (MCU) 101 driven by a clock oscillator 105.
Is a PROM 102 storing a program for driving and controlling the microcomputer 1, and a main operation control circuit 1
SRAM 10 for storing data required for 01 arithmetic control
3, a timer / counter 104 having a counting function as a timer and a counter, and 8ch A which is an external analog input
It has an A / D converter 106, a parallel port 107 for external digital input, an interrupt controller 108 for interrupt control, a serial communication interface 109 for serially outputting a vehicle speed calculation result, and the like, which are a data address control bus 110. It is connected by bus.

<Overall Basic Operation of Circuit Configuration> The ultrasonic transmission / reception circuit 20TR operates as follows.

From the ultrasonic wave transmitter / receiver TR1, a frequency of 200
[KHz], burst time of 1 [msec] 10 [ms
every ec], a gate signal for outputting a burst wave is output from the terminal P1 of the parallel port 107 of the microcomputer 1 for each transmission. The switching transistor 6 is turned on / off by the output of the frequency dividing circuit 7 to boost the voltage.
The output of 0 [KHz] causes the ultrasonic transducer TR1 to generate ultrasonic waves. At this time, the transmission / reception switching circuit 3 prevents an excessive signal from being applied to the input of the preamplifier 4 on the receiving side during the transmission operation.

When the ultrasonic wave transmitter / receiver TR1 receives the reflected wave from the road surface, it is amplified by the preamplifier 4 to about 80 [dB], and then the bandpass filter 8 is set to about 200 ± 5.
Only the signal of 0 [KHz] is taken out, further amplified, then binarized by the comparator 10, and the frequency detection PLL is used.
It is input to the circuit 12 and the frequency of the reflected wave from the road surface is detected. The output of the comparator 10 is a frequency detection PL
The L circuit 12 performs sampling and holding for a time period for detecting a specific reflected wave from the road surface, and holds the voltage thereof to hold a specific detection frequency of the reflected wave from the road surface. The output of the voltage controlled oscillator VCO is 1/8
And is fed back to the phase difference detection circuit PD and is thereby locked at a frequency that is eight times the reflection frequency input to the ultrasonic transducer TR1. Therefore, if the microcomputer 1 counts the output of the voltage controlled oscillation circuit VCO, the Doppler frequency is detected based on the emitted ultrasonic frequency and the reflected ultrasonic frequency. In this embodiment, a resolution of about 0.5 [Km / h] or higher was obtained in terms of vehicle speed.

The ultrasonic transmission / reception circuit 30TR and the ultrasonic transmission / reception circuit 40TR operate in the same manner, but the explanation of the operation will be omitted.

<Main Control Operation by Microcomputer> FIGS. 4 and 5 are flowcharts of a main program executed by the microcomputer 1 of the vehicle-mounted ultrasonic measuring device according to the embodiment of the present invention. 6 is a flowchart of an interrupt routine executed by the microcomputer 1 of the vehicle-mounted ultrasonic measurement device according to the embodiment of the present invention, and FIG. 7 is executed by the microcomputer 1 of the vehicle-mounted ultrasonic measurement device according to the embodiment of the present invention. 6 is a flowchart of a gate position calculation control to be performed.

FIG. 8 is a timing chart of control of the vehicle-mounted ultrasonic measuring device according to the embodiment of the present invention. In addition,
The basic operation is the same as the operation of the ultrasonic transmission / reception circuit 20TR, the ultrasonic transmission / reception circuit 30TR, and the ultrasonic transmission / reception circuit 40TR. Therefore, the operation will be mainly described here with reference to the ultrasonic transmission / reception circuit 20TR. 30 TR
The ultrasonic transmission / reception circuit 40TR is also controlled in the same manner.

When a power supply (not shown) is turned on, a reset pulse is input to the main operation control circuit 101 by the function of the power-on reset circuit, and this reset causes PR.
The processing of the main program of FIGS. 4 and 5 stored in the OM 102 is started.

In step S1, the ultrasonic wave transmitting / receiving circuit 20T
R, ultrasonic transmission / reception circuit 30TR, and ultrasonic transmission / reception circuit 4
Various memories of 0TR, counters, and timers are cleared or set to predetermined values, and initialization processing for initializing each output port and the like is performed. Particularly, the reception gate start time TG and the sampling start time Ts are set. The reception gate start time TG sets the reception time of the ultrasonic signal corresponding to the mounting height of the vehicle 100 in the standard state as a default value. For example, the mounting height is 280
[Mm], ultrasonic radiation angle is 45 degrees, sound velocity C = 34
When 5 [m / s] is set, TG = 2 × 0.28 / sin45 × 1/345 + 0.3 × 10 ⁻³ = 2.6 [msec]. Here, 0.3 [msec] is added because the position of the reception gate width 0.5 [msec] is set to the center of the reception wave with respect to the transmission pulse width 1 [msec]. is there.

In step S2, the 10 msec sequence end flag F10 for judging the end of the 10 [msec] sequence, the sampling permission flag Fs, and the main timer T are cleared. In step S3, a 100 μsec timer interrupt that interrupts every 100 [μsec] is enabled, and in step S3
In step 4, it is determined whether the 10 msec sequence end flag F10 has come down, and the process waits until the 10 msec sequence end flag F10 comes down, and the subsequent processing is performed every 10 [msec]. 10
When the msec sequence end flag F10 goes down, step S
At step 5, the switching transistor 6 is turned on to open the transmission gates of the ultrasonic transmission / reception circuit 20TR, the ultrasonic transmission / reception circuit 30TR, and the ultrasonic transmission / reception circuit 40TR, and step S6
Then, the main timer T judges whether 1 msec has elapsed, and the step S
7, the ultrasonic transmission / reception circuit 20TR and the ultrasonic transmission / reception circuit 30
The transmission gate of TR and the ultrasonic wave transmission / reception circuit 40TR is closed. As a result, a burst signal of ultrasonic waves of 1 [msec] is output. That is, as shown in FIG. 8, in steps S4 to S7, the transmission gate is opened by 1 every 10 [msec] of the output terminal P1 of the microcomputer 1.
It is carried out by "1" for [msec], and during that period, it becomes a burst signal indicated by the output e1 of the frequency dividing circuit 2, and the ultrasonic wave transmitter / receiver TR1, the ultrasonic wave transmitter / receiver TR2, and the ultrasonic wave transmitter / receiver TR3 are transmitted. Becomes the output e2. Further, the reflected wave is the ultrasonic wave transmitter / receiver TR1, the ultrasonic wave transmitter / receiver TR.
2. Output e3 is obtained via the ultrasonic wave transmitter / receiver TR3.

Up to this point, when ultrasonic waves are simultaneously transmitted, the ultrasonic wave transmitting / receiving circuit 20TR, the ultrasonic wave transmitting / receiving circuit 30TR, and the ultrasonic wave transmitting / receiving circuit 40TR are simultaneously controlled. However, after that, since the predicted sampling start time Ts for inputting the reflected wave is different for each of the ultrasonic wave transmitting / receiving circuit 20TR, the ultrasonic wave transmitting / receiving circuit 30TR, and the ultrasonic wave transmitting / receiving circuit 40TR, the ultrasonic wave transmitting / receiving circuit 20TR, the ultrasonic wave transmitting / receiving circuit 20TR Although the circuit 30TR and the ultrasonic transmission / reception circuit 40TR are individually controlled, in order to prevent the description from being complicated, the description of common items is omitted in this embodiment.

In step S8, the ultrasonic wave transmitting / receiving circuit 20TR
(Ultrasonic transceiver circuit 30TR, ultrasonic transceiver circuit 40T
For each R), the predicted sampling start time Ts at which the received signal of the reflected wave is input is determined, and when the sampling start time Ts arrives, the sampling permission flag Fs is set in step S9, and the initially set value or gate position calculation is performed. Each reception gate start time T obtained in the processing routine
Wait for the arrival of G in step S10. When each reception gate start time TG arrives, each reception gate of each ultrasonic transmission / reception circuit 20TR (ultrasonic transmission / reception circuit 30TR, ultrasonic transmission / reception circuit 40TR) is opened in step S11, and 0.5 [msec] in step S12. After turning on the receiving gate only, the receiving gate is turned off in step S13, and the process of step S14 starts. That is, in steps S8 to S13, the arrival of each reception gate start time TG for each ultrasonic transmission / reception circuit 20TR (ultrasonic transmission / reception circuit 30TR, ultrasonic transmission / reception circuit 40TR) is determined, and each ultrasonic transmission / reception circuit 20TR Corresponding to the sound wave transmission / reception circuit 30TR and the ultrasonic wave transmission / reception circuit 40TR, a reception gate for passing the reflected ultrasonic waves is opened and closed.

Then, in step S14, the counter COUNT1 (counters COUNT2, CO
The gate of UNT3) is opened, and it is determined in step S15 whether 3 [msec] has elapsed from the sampling start time Ts.
That is, the sampling start time Ts is ± 1.5 [msec] from the center of the ON time of the receiving gate, and the terminal Aoin of the A / D converter built in the microcomputer 1
A signal for each ultrasonic transmission / reception circuit 20TR (ultrasonic transmission / reception circuit 30TR, ultrasonic transmission / reception circuit 40TR) is input to (A / D converter terminals A1in, A2in), and an incoming signal is sampled. When 3 [msec] has elapsed from each sampling start time Ts, the sampling permission flag Fs is cleared in step S16. Step S17
In the main timer T, the time for which the gate of the counter is opened depends on the ultrasonic transmitter / receiver circuit 20TR
0TR, 2.5 msec has elapsed from the reception gate start time TG for each ultrasonic transmission / reception circuit 40TR), the count value of the counter is read in step S18, the gate of the counter is closed, and the two-dimensional velocity is calculated in step S19. And so on.

The calculation of the respective velocities V1, V2 and V3 is as follows: V1 = K * countX1 V2 = K * countX2 V3 = K * countX3 where countX1, X2, X3: coefficient values of counter K: coefficient determined by atmospheric temperature Do as. Further, the distance and the acceleration can be calculated by integrating and differentiating the velocity vector, and the lateral velocity Vy of the vehicle 100, the yaw rate ω of the vehicle 100, and the vehicle 10 can be calculated.
The centrifugal force applied to 0 can be calculated. Of course, it is also possible to calculate the rotational angular velocity about the central axis passing through the center of gravity of the vehicle 100, that is, the yaw rate.

In step S20, the gate position calculation processing routine is called. Then, in step S21, the sampling time is set 1.2 [msec] ahead of the reception gate start time TG to the sampling start time Ts. That is, the gate position calculation processing routine determines the next reception gate start time TG. And step S
In step 22, the 10 msec sequence end flag F10 is set, the atmospheric temperature is read in step S23, the value of the proportional constant K used in the next vehicle speed calculation is determined, and the routine from step S4 onward is repeated and executed.

<Timer Interrupt Operation of Microcomputer> In step S31, the main timer T is incremented by "+1", and in step S32, it is judged by the main timer T whether or not it is the interrupt timing every 100 [μsec], and in step S32, the interrupt is executed. If it is determined that the timing of step S33 and step S34 is 10
The 10 msec sequence end flag F10 for judging the end of the [msec] sequence is cleared and the main timer T is cleared. When it is determined that it is not the timing of the interrupt, the processing of steps S33 and S34 is avoided.

In step S35, it is determined whether or not the sampling permission flag Fs is set. When the sampling permission flag Fs is set, the A / D conversion is started by the output of the reception level detection circuit 11 in step S36.
In step S37, it is written in the buffer, and this routine is exited. If it is determined in step S35 that the sampling permission flag Fs is not set, this routine is exited.

That is, in this routine, the main timer T
The signal level is sampled through the signal level detection circuit 11 every 0.1 [msec], and the signal level is stored in the buffer incorporated in the main operation control circuit 101.

<Gate Position Control Operation by Microcomputer> Reception level data sampled by sampling by interruption every 0.1 [msec] is 15 samples before and after the central sample data, that is, 31 sample data in total. Exists. First, in step S51, an average value X is calculated by a simple average of all level data, and in step S52, the level value of the central sample data is used as the reception level data in the sample center data storage memory X
Store in c. In step S53, it is determined whether or not this is larger than the value obtained by adding a predetermined amount n to the average value X than the level value of 15 samples before and after, and the level value of the central sample data and the level value of 15 samples before and after are the predetermined average value. When the value is larger than the value obtained by adding a predetermined amount n to X, it means the data in which the target reflected wave is regularly reflected, so the process of step S54 is started to adopt this. However, when the level value of the central sample data and the level values of 15 samples before and after are not larger than the value obtained by adding the predetermined amount n to the predetermined average value X, the received waveform is distorted by random interference. Therefore, the adoption of this data is prevented. In step S54, a data period exceeding the value obtained by adding the predetermined amount n to the average value X of all the level data is searched before and after, and the previous time T1 and the subsequent time T are searched.
Ask for 2. In step S55, the width of T2-T1 is 1 [ms
ec], it is determined whether or not the timing for obtaining the reception level data is sufficiently covered. This judgment also prevents the adoption of data in which the received waveform is distorted by random interference. Then, in step S56, (T2 + T1) / 2 is set as the reception gate start time TG. When it is not larger than the value obtained by adding the predetermined amount n to the average value than the central sample level value in step S53, and the width of T2-T1 is 1 [ms in step S55.
ec] and the timing for obtaining the reception level data is not sufficiently covered, this routine is exited.

As described above, the ultrasonic measuring device for vehicle according to the present embodiment sets the depression angle to 45 degrees with respect to the traveling direction, transmits the ultrasonic wave from there, and receives the reflected wave from the road surface. The oscillating ultrasonic wave transceiver TR1 obtains a velocity V1 with respect to the traveling direction of the vehicle and uses it as the vehicle velocity directly. That is, the ultrasonic wave transmitter / receiver TR1 is parallel to the traveling direction of the vehicle, transmits ultrasonic waves with a predetermined depression angle gradient with respect to the road surface, and receives a reflected wave from the road surface. One ultrasonic wave transmitter / receiver can be used.

The ultrasonic wave transmitter / receiver TR1 as the first ultrasonic wave transmitter / receiver is equidistant from the straight line parallel to the traveling direction of the vehicle 100 on both sides by an equal angle ± δ and has a predetermined distance from the road surface. Ultrasonic wave transmitter / receiver TR2 and ultrasonic wave transmitter / receiver TR2 as two second ultrasonic wave transmitters / receivers which transmit ultrasonic waves with a depression angle gradient of and receive reflected waves from the road surface The ultrasonic wave transmitter / receiver TR3 is provided, and the ultrasonic wave transmitter / receiver TR2 and the ultrasonic wave transmitter / receiver TR3 are separated from each other by equal angles ± δ on both sides with respect to a straight line parallel to the traveling direction of the vehicle 100, Ultrasonic waves are transmitted with a predetermined depression angle gradient with respect to the road surface, and the speed V2 and the speed V3 in the directions deviated by ± (180-δ) degrees from the vehicle speed are obtained. That is, if the velocity V1 as the vehicle velocity obtained by the ultrasonic transducer TR1 is the X-axis velocity component, the velocity V2 and the velocity V3 are Y in the direction perpendicular to the straight line parallel to the traveling direction of the vehicle 100.
It will have an axial velocity component. This Y-axis velocity component is the lateral velocity of the vehicle 100. Further, it is necessary to provide a predetermined space between the ultrasonic wave transmitter / receiver TR2 as the second ultrasonic wave transmitter / receiver and the ultrasonic wave transmitter / receiver TR3 as the third ultrasonic wave transmitter / receiver. The difference in the rotational speed of the wheels appears as the vehicle speed in a straight line parallel to the traveling direction of the vehicle 100 at the speed V2 and the speed V3.

Therefore, in the speed calculation of step S19 as the calculating means of the above-mentioned embodiment, the vehicle 10 is calculated by the two-dimensional speed components of the X-axis speed component and the Y-axis speed component.
A velocity Vx of 0 in the traveling direction and a velocity Vy of the vehicle 100 in the direction perpendicular to the traveling direction can be obtained. Further, by calculating the yaw angle and the changing speed of the angle, the yaw rate and the velocity vector are integrated and differentiated, whereby the distance and the acceleration can be calculated, and the rotation speed about the center axis of the vehicle 100, and The differential angular acceleration can also be calculated.

Therefore, by using the obtained speed component, the correction of the moving distance and the moving direction of the navigation system, the speed detection device such as the vehicle speed and the lateral speed, the skid prevention device, the yaw rate correction, and the left and right correction are performed. It can be used for a measuring device and a control device using various speed information such as an ABS device that corrects a wheel rotation difference, a yaw rate correction, and a suspension device that adjusts the vehicle height between the road surface on the left and right wheel sides and the vehicle.

By the way, in the above embodiment, the vehicle speeds in three directions are detected by the three ultrasonic wave transmitters / receivers TR1, the ultrasonic wave transmitters / receivers TR2 and the ultrasonic wave transmitters / receivers TR3.
When the present invention is carried out, the sound velocity is not so high as to be negligible with respect to the vehicle speed. Therefore, when the ultrasonic beam width is narrowed in order to increase the total gain of the transmitted and received waves, the At this time, there is a shift in the beam when receiving waves.Therefore, at this time, the ultrasonic wave transmitter / receiver is used to measure the speed during low speed traveling, and the reflected wave is received by the ultrasonic wave receiver for measuring the speed during high speed traveling. The ultrasonic wave transmitter / receiver circuit 20TR, the ultrasonic wave transmitter / receiver circuit 30TR, and the ultrasonic wave transmitter / receiver circuit 40TR each use two ultrasonic wave transmitters / receivers. Only one may be dedicated to receiving ultrasonic waves. Further, in particular, the ultrasonic transmission / reception circuit for detecting the speed parallel to the traveling direction of the vehicle is composed of two ultrasonic wave transmitters / receivers and an ultrasonic wave transmitter / receiver, or an ultrasonic wave transmitter / receiver and an ultrasonic wave receiver,
Reliable speed can be obtained by changing the position where the reflected wave is received according to the vehicle speed.

In the embodiment of the present invention, a straight line passing through the ultrasonic wave transmitter / receiver TR1 arranged parallel to the traveling direction of the vehicle is set as a line object, and both sides are separated from each other by an equal angle ± δ. However, in the case of carrying out the present invention, the ultrasonic transducer T arranged parallel to the traveling direction of the vehicle.
The ultrasonic wave transmitter / receiver TR with the straight line passing through R1 as the line object
2. It is not necessary to dispose the ultrasonic wave transmitter / receiver TR3, and it is sufficient that the ultrasonic wave transmitter / receiver TR2 and the ultrasonic wave transmitter / receiver TR3 can be line objects parallel to the traveling direction of the vehicle. However, when the ultrasonic wave transmitter / receiver TR1 is arranged in the middle of the vehicle 100, the reliability of the vehicle speed becomes highest. At this time, if the ultrasonic wave transmitter / receiver TR2 and the ultrasonic wave transmitter / receiver TR3 are arranged with a straight line passing through the ultrasonic wave transmitter / receiver TR1 as a line object, the wheel difference of the vehicle 100 multiplies the coefficient between them. Directly, and the vector combination increases the calculation speed of the two-dimensional speed component.

Although the vehicle speed measurement has been described in the embodiment of the present invention, the vehicle-mounted ultrasonic measuring device according to the present invention uses the speed component to provide a navigation system, a speed detecting device, a skid prevention device, ABS equipment,
It can be used for measuring devices and control devices that use various speed information such as suspension devices.

[0062]

As described above, the in-vehicle ultrasonic measuring device of the present invention transmits ultrasonic waves in parallel with the traveling direction of the vehicle with a predetermined depression angle inclination with respect to the road surface, and transmits from the road surface. A first ultrasonic wave transmitter / receiver for detecting a vehicle speed that receives a reflected wave, and a predetermined distance at equal angles on both sides with respect to a straight line parallel to the traveling direction of the vehicle of the first ultrasonic wave transmitter / receiver 2 ultrasonic wave transmitters / receivers and a third ultrasonic wave transmitter / receiver which transmit ultrasonic waves with a predetermined inclination to the road surface and receive reflected waves from the road surface. According to the above, the velocity vectors obtained by them are combined by the computing means to compute the two-dimensional velocity of the vehicle.

Therefore, the first ultrasonic wave transmitter / receiver, which transmits ultrasonic waves with a predetermined depression angle gradient to the road surface and receives the reflected waves from the road surface, can directly detect the vehicle speed. . Moreover, two second ultrasonic wave transmitters / receivers and a third ultrasonic wave transmitter / receiver, which are arranged at equal angles on both sides with respect to a straight line parallel to the traveling direction of the vehicle and are separated from each other by a predetermined distance, The wave device will obtain a velocity in a direction deviated from the vehicle velocity by a predetermined angle, and as a result, a velocity component in a direction perpendicular to a straight line parallel to the traveling direction of the vehicle can be obtained, and By providing a predetermined distance between the second ultrasonic wave transmitter / receiver and the third ultrasonic wave transmitter / receiver, the rotational speed difference speed between the left and right wheels of the vehicle can be obtained. With this, the yaw angle and yaw rate can be calculated. Further, by integrating and differentiating the velocity vector, the distance and the acceleration can be calculated, and their loci can be traced, which can be used for the measuring device and the control device.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a basic principle of an in-vehicle ultrasonic measuring device according to an embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of an in-vehicle ultrasonic measuring device according to an embodiment of the present invention.

FIG. 3 is a functional configuration diagram of a microcomputer used in the circuit configuration of the vehicle-mounted ultrasonic measurement device according to the embodiment of the present invention.

FIG. 4 is a flowchart of a part of a main program executed by the microcomputer of the vehicle-mounted ultrasonic measurement device according to the embodiment of the present invention.

FIG. 5 is a flowchart of another part of the main program executed by the microcomputer of the vehicle-mounted ultrasonic measurement device according to the embodiment of the present invention.

FIG. 6 is a flowchart of an interrupt routine executed by the microcomputer of the vehicle-mounted ultrasonic measurement device according to the embodiment of the present invention.

FIG. 7 is a flowchart of gate position calculation control executed by the microcomputer of the vehicle-mounted ultrasonic measurement device according to the embodiment of the present invention.

FIG. 8 is a timing chart of control of the vehicle-mounted ultrasonic measurement device according to the embodiment of the present invention.

FIG. 9 is an operation principle diagram when transmitting and receiving by one ultrasonic wave transmitter / receiver of the vehicle-mounted ultrasonic measuring device.

[Explanation of symbols]

 TR1, TR2, TR3 ultrasonic wave transmitter / receiver 11 reception level detection circuit 12 frequency detection PLL circuit 20TR ultrasonic wave transmission / reception circuit 30TR ultrasonic wave transmission / reception circuit 40TR ultrasonic wave transmission / reception circuit 100 vehicle

Claims (1)

[Claims] 1. A first ultrasonic transducer, which is parallel to a traveling direction of a vehicle, transmits an ultrasonic wave with a predetermined depression angle gradient to a road surface, and receives a reflected wave thereof. With respect to a straight line parallel to the traveling direction of the vehicle of the ultrasonic wave transmitter / receiver, the ultrasonic waves are transmitted on both sides at equal angles with each other by a predetermined distance, and have a predetermined depression angle gradient with respect to the road surface, Two second ultrasonic wave transmitters / receivers and a third ultrasonic wave transmitter / receiver for receiving the reflected waves, the first ultrasonic wave transmitter / receiver, the second ultrasonic wave transmitter / receiver, and a third ultrasonic wave transmitter / receiver
An in-vehicle ultrasonic measuring device, comprising: an ultrasonic wave transmitter / receiver; and a calculating means for calculating a two-dimensional velocity of a vehicle by synthesizing velocity vectors obtained by them.