JPH09236663A - Obstacle detecting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the accuracy in detection by having a step motor rotating a mirror for emission of a light beam and by controlling a rotational position of the step motor so that the rotational position of the mirror be made to coincide with the initial position. SOLUTION: A mirror case 26 rotates and comes into contact with a stopper S on one side of a base 26a thereof. Therefore the initial position of a step motor 25, i.e., the initial position of a mirror 29, is determined. As the result, a rotational position of the mirror 29 is set initially at one-side end of rotation thereof. A cyclic process of a step motor scanning routine is repeated thereafter. When a light beam is reflected by an obstacle, according to this constitution, the position of presence of the obstacle can be detected accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an obstacle detection system suitable for detecting an obstacle existing in front of or behind a moving body such as a vehicle.

[0002]

2. Description of the Related Art Conventionally, for example, in an obstacle detection system for a vehicle, as disclosed in Japanese Utility Model Laid-Open No. 3-95979, a laser beam reflected by a mirror is emitted toward the front of the vehicle. There is a device which detects an obstacle based on the reflected laser light when the emitted laser light is reflected by the obstacle ahead.

In this obstacle detection system, in order to widen the obstacle detection range, the mirror is reciprocated by a DC motor over a predetermined angle range.

[0004]

However, as described above,
The reciprocating position of the mirror at the time of starting the detection of the obstacle cannot be specified by simply reciprocating the mirror by the DC motor over a predetermined rotation range. For this reason, there is a problem in that it is difficult to identify the position of the detection obstacle in the predetermined rotation range during the rotation process of the mirror.

Further, in the drive by the DC motor, the rotation of the motor is unstable, so that it is difficult to specify the position of the detection obstacle in the predetermined rotation range.
Therefore, the present invention, in order to deal with the above,
The step motor is used as the driving source of the mirror that reflects the laser beam toward the obstacle, and the obstacle detection is designed to improve the detection accuracy by maintaining the mirror at a predetermined initial position when the detection of a wide range of obstacles is started. The purpose is to provide a system.

[0006]

In order to achieve the above object, according to the invention described in claims 1 and 2, the beam light emitting means has a step motor for rotating the mirror,
At the start of obstacle detection, the drive control means controls the turning position of the step motor so that the turning position of the mirror coincides with the initial position.

As a result, the subsequent rotation of the step motor is controlled by the drive control means on the basis of the initial position. For this reason, when the light beam is reflected by an obstacle, the mirror is set to the initial position in advance as described above and the step motor is used, so that the turning position of the mirror is based on the initial position. As a result, it is accurately calculated under the step action of the step motor. As a result, the location of the obstacle can be detected accurately.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a schematic configuration of a vehicle obstacle detection system according to the present invention. The obstacle detection system includes a light emitting circuit 10,
The light emitting circuit 10 emits laser light. The light emitting circuit 10 also outputs the light emission timing of the laser light as a timing signal to the microcomputer 60 described later.

The laser light emitting device 20 includes a mirror mechanism 20a mounted at a proper position of the vehicle and the mirror mechanism 20a.
And an emission lens 20b that emits the laser light from the vehicle toward the front of the vehicle. The mirror mechanism 20a is
A base 21 having a shape shown in FIGS. 2 to 4 is provided, and the base 21 is horizontally mounted at a proper position of the vehicle by a flange 21a thereof.

Further, the mirror mechanism 20a is provided with an idle gear train 22, and the idle gear train 22 has an upper end of a rotary shaft 24 which is rotatably supported in the boss 21b of the base 21 via both bearings 23. Is coaxially supported. The idle gear train 22 includes a large-diameter gear 22a and a small-diameter gear 22b coaxially and integrally formed on the large-diameter gear 22a.
And (see FIG. 3).

As shown in FIG. 4, the mirror mechanism 20a has a step motor 25, which is fixed to the upper wall of the recess 21c of the base 21. . The pinion gear 25a has a recess 21c.
The pinion gear 25a is coaxially supported by the rotation shaft of the step motor 25 extending through the opening of the upper wall.
Engages with the large-diameter gear 22a of the idle gear train 22.

Further, the mirror mechanism 20a is shown in FIGS.
As shown in, the mirror case 26 is provided, and the mirror case 26 has a lower surface side boss 2 of the substrate portion 26a.
At 6b, it is coaxially supported on the upper end of the rotary shaft 28. The rotating shaft 28 is rotatably supported in the boss 21d of the base 21 via both bearings 27. Substrate 2
An arcuate internal gear 26c is formed on the lower surface of 6a, and this internal gear 26c meshes with the small-diameter gear 22b of the idle gear train 22. Thus, the mirror case 26 rotates about the boss 26b while meshing with the small diameter gear 22b by the internal gear 26c.

The mirror case 26 has a substrate portion 26a.
There is a case portion 26d having an L-shaped cross section that extends vertically from the plate mirror 29 is vertically accommodated in the case portion 26d. This mirror 29 is used for the light emitting circuit 1.
The laser light from 0 is reflected toward the emission lens 20b. A stopper S is formed on the upper wall of the base 21 as shown by a solid line in FIG.
Is the upper wall 2 of the base 21 below the mirror case 26 in the figure.
It is fixed on 1e. Here, this stopper S is
It plays a role of specifying the initial position of the mirror case 26, that is, the mirror 29 (corresponding to the one-side rotating end of the mirror 29 in FIG. 2).

In FIG. 3, reference numeral 26e indicates a torsion coil spring, and the torsion coil spring 26e biases the mirror case 26 in one rotation direction with respect to the base 21. However, the play between the idle gear train 22 and the pinion gear 25a is absorbed. In this case, the spring force of the torsion coil spring 26e is smaller than the holding force due to the detent torque of the step motor 25.

The obstacle detection system also has a light-receiving lens 30, which collects the laser light from the emission lens 20b reflected by the reflector R of the vehicle in front, for example. The photodiode 40 is made to receive light. The photodiode 40 converts the received laser light into a detection signal. The amplifier 50 amplifies the detection signal from the photodiode 40 and outputs it to the microcomputer 60.

The microcomputer 60 executes a computer program based on the outputs of the light emitting circuit 10 and the amplifier 50 according to the flowchart shown in FIG. The microcomputer 60 has the light emitting circuit 1
0 and arithmetic processing for driving and controlling the drive circuit 70 of the step motor 25 are performed. The drive circuit 70 is controlled by the microcomputer 60 to control the step motor 2
Rotate 5 back and forth. The microcomputer 60 operates by turning on the power.

In the present embodiment thus constructed, when the microcomputer 60 is activated by turning on the power source, the vehicle speed of the vehicle is determined in step 100. If the vehicle speed is 10 km / h or more, the determination in step 100 is YES, and the next step 1
At 10, the position initialization process of the step motor 25 is performed.

That is, during a time period sufficient to bring the substrate 26a of the mirror device 26 into contact with the stopper S on one side thereof, an initial rotation signal (a rotation direction indicated by reference symbol A in FIGS. 7 and 8) is used. Signal) to the drive circuit 70. Then, the step motor 25 is driven by the drive circuit 70 based on the initial rotation signal to rotate in the A direction, the small-diameter gear 22a of the idler gear train 22 is rotated by the pinion 25a, and the internal gear 26c moves to the idler gear train 22. The large diameter gear 22b is rotated.

As a result, the mirror device 26 rotates and contacts the stopper S at one side of the substrate 26a. Therefore, the initial position of the step motor 25, that is, the mirror 25
The initial position of is determined. As a result, the turning position of the mirror 25 is initially set to the one-side turning end (see FIG. 6).
After that, if the vehicle speed is 10 km / h or more, the process of circulating the step motor scanning routine 120 and step 130 is repeated.

In the step motor scan routine 120,
Light emission start processing of the light emitting circuit 10 is performed. Therefore, the light emitting circuit 10 emits a laser beam and a timing signal indicating the light emission timing is supplied to the microcomputer 6
Output to 0. Further, a reciprocal rotation signal (a signal in the rotation direction indicated by both symbols A and B in FIGS. 7 and 8) for reciprocally rotating the step motor 25 is output to the drive circuit 70.

In this way, the reciprocating rotation signal is the drive circuit 70.
Is output to the drive circuit 70.
It is driven by and reciprocally rotates. Along with this, the mirror 2
9 is driven by the step motor 25 via the pinion 25a and the idler gear train 22, and the point O in FIG.
Reciprocating rotation (corresponding to the axis of the rotating shaft 28) is performed (see FIGS. 7 and 8). In this case, the mirror 29 starts to rotate from its initial position, rotates 8 degrees in the B direction over 144 msec, and then rotates in the A direction and returns to the initial position over 56 msec. The step motor 25 is rotated by 0.25 ° every 4.5 msec in 32 steps.

When the light emitting circuit 10 emits a laser beam as described above, the laser beam is reflected by the mirror 29, passes through the emitting lens 20b, and is emitted toward the front of the vehicle. In this case, the forward irradiation direction of the laser light changes over the range indicated by the symbol C in FIG. 8 according to the reciprocating rotation of the mirror 29. In this state, when the emitted laser light is reflected by the reflector R of the oncoming vehicle, the reflected laser light is received by the light receiving lens 30 and enters the photodiode 40. Then, the detection signal of the photodiode 40 is amplified by the amplifier 50 and output to the microcomputer 60.

Then, the timing signal and the amplifier 50
From the output to the microcomputer 60, the rotation angle of the mirror 29 is calculated based on the number of steps of the step motor 25, and the position of the reflector R is determined based on this rotation angle. However, the rotation angle of the mirror 29 is calculated during the rotation process in the A direction. In this case, as described above, since the initial position of the mirror 29 is set in advance and the step motor 25 is used, the rotation angle of the mirror 29 thereafter is set to the step motor 25 with reference to the initial position. Under the step action,
Calculated accurately. As a result, the reflector R that is an obstacle
The presence position of can be detected accurately. The pinion 25
Since the play between the meshing teeth of the a, the idler gear train 22 and the internal gear 26c is eliminated by the urging force of the torsion coil spring, the play described above causes an error in the obstacle detection result during the rotation process of the mirror 29. There is no mixing.

Next, FIG. 9 shows a modification of the above embodiment.
This will be described with reference to FIGS. In this modified example, instead of the mirror case 20d of the mirror mechanism 20a described in the above embodiment, a mirror case 80 integrally formed of an elastic resin material is adopted. This mirror case 80
Is a lower surface side boss 81a of the substrate portion 81 (corresponding to the substrate portion 26a of the mirror case 20d described in the above embodiment) (the mirror case 20d described in the above embodiment.
Corresponding to the lower surface side boss 26b) is coaxially supported by the upper end of the rotating shaft 28 described in the above embodiment. An arc-shaped internal gear 81b (corresponding to the arc-shaped internal gear 26c described in the above embodiment) is formed on the lower surface of the substrate portion 81, and the internal gear 81b is an idle gear train. It meshes with the small diameter gear 22b of No. 22.

Further, the mirror case 80 has a plate-shaped case portion 82 (which corresponds to the case portion 26d of the mirror case 26 described in the above embodiment) which extends vertically from the substrate portion 81, The plate-shaped mirror 29 described in the above embodiment is vertically housed in the case portion 82 (see FIG. 9). Here, the mirror 2 of the mirror case 80
The accommodating structure for 9 will be described in detail with reference to FIGS. 9 to 11. At the upper edge intermediate portion of the plate-shaped case portion 82,
The claw 83 is integrally formed so as to extend forward (toward the mirror 29 side), and the claw 83 has its L-shaped tip portion 83 a for connecting the upper edge of the mirror 29 to the inner wall of the case portion 82. Sandwiched between. In FIG. 10, reference numeral 83b denotes a tip portion 83 of the claw 83 when the mirror case 80 is integrally molded.
The punched hole required for molding a is shown.

At the middle portion of the left side edge of the plate-like case portion 82,
The claw 84 is integrally formed so as to extend toward the front. The claw 84 holds the left edge of the mirror 29 between the claw 84 and the inner wall of the case 82 at its L-shaped tip 84a. There is. Note that, in FIG. 10, reference numeral 84b indicates a hole required for molding the tip end portion 84a of the claw 84 when the mirror case 80 is integrally molded.

At the middle portion of the right side edge of the plate-shaped case portion 82,
As shown in FIGS. 9 to 11, the claw 85 is integrally molded, and the claw 85 extends from the rear surface of the case portion 82 toward the front in a U shape, and has an L-shaped tip portion 85a. ,
The right edge of the mirror 29 is elastically held between the right edge of the mirror 29 and the inner wall of the case 82. Further, as shown in FIGS. 9 to 11, each of the cut-and-raised parts 86 to 88 is cut and raised toward the front side in the case part 82.
Each of the cut-and-raised parts 86 to 88 presses the back surface of the mirror 29 forward by elastic force at its tip parts 86a to 88a and presses it against the tip parts of the claws 83 to 85.

As described above, the mirror 29 is mounted on the case portion 8 by the elasticity of the claw 85 and the cut-and-raised portions 86 to 88 by the claws 83 to 86 formed integrally with the case portion 82.
Since the mirror 29 is housed in the mirror case 80 by sandwiching the mirror 29 with the mirror 2, it is possible to use the mirror case 80 without using an adhesive or the like.
The mirror 29 can be firmly fixed in the mirror case 80 for a long period of time without being affected by vibration or the like in the mirror case 80 and without being displaced.

In this case, in this fixing, as described above, it is only necessary to form the claws 83 to 86 on the case portion 82, so that the mirror 29 is fixed to the case portion 82.
It can be realized with a simple configuration. When replacing the mirror 29 with a new one, the elasticity of the claw 85 is resisted and the mirror 29
Since it can be easily removed from the case 82,
The above replacement is easy. Other configurations and operational effects are similar to those of the above embodiment.

In implementing the present invention, the spring force of the torsion coil spring 26e is set to be larger than the holding force of the step motor 25 due to the detent torque and smaller than the rotational force of the step motor 25 when the power is turned on. In this case, even if the microcomputer 60 does not initialize the rotational angle position of the step motor 25, the torsion coil spring 26e causes the step motor 2 to rotate.
The rotation angle position of 5 can be initialized.

Further, in the above-described embodiment, an example in which the double bearings 27 are adopted as the means for rotatably supporting the rotating shaft 28 in the boss 21d of the base 21 has been described. Alternatively, a miniature ball bearing may be adopted. In this case, in these miniature ball bearings, since the clearance between the inner ring and the outer ring is very small, the rattling of the rotating shaft 28 in the radial direction can be suppressed to the minimum.

As a result, the degree of tilt of the mirror 29 in the vertical direction can be suppressed to a minimum. Further, in carrying out the present invention, not only when detecting an obstacle in front of the vehicle, but also when detecting an obstacle behind the vehicle, even if the present invention is applied and executed, The same effect as the form can be achieved.

Further, in carrying out the present invention, instead of the stopper S, a stopper Sa may be adopted as shown by a chain double-dashed line in FIG. Here, the stopper Sa is fixed to the upper wall of the base 21 above the substrate 26a of the mirror device 26 in FIG. Therefore, the substrate 26a contacts the stopper Sa at the other side rotation end.
Also by this, the initial position of the mirror 29 is set in the same manner as described in the above embodiment. Therefore, it is possible to achieve the same effect as that of the above embodiment.

In implementing the present invention, a switch is used instead of the stopper S, and the mirror device 26 is
The step motor 25 may be prevented from rotating in the A direction by rotating the switch in the direction A and contacting the switch. Further, in carrying out the present invention, not only laser light but also light in the form of a beam (beam light) may be used, and this beam light can also achieve the same effect as the above-mentioned embodiment.

In implementing the present invention, the present invention may be applied to not only vehicles but also obstacle detection systems for various moving bodies such as ships and aircrafts.

[Brief description of drawings]

FIG. 1 is a schematic overall configuration diagram of an obstacle detection system according to the present invention.

FIG. 2 is a plan view of the laser light emitting device of FIG.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is a sectional view taken along line 4-4 in FIG. 2;

5 is a flowchart showing the operation of the microcomputer of FIG.

FIG. 6 is a plan view showing a contact state with a stopper of the mirror device.

FIG. 7 is a plan view showing a rotating state of the mirror device.

FIG. 8 is an explanatory diagram showing changes in the emission direction of laser light when the mirror is rotated.

FIG. 9 is a plan view showing a main part of a modified example of the above embodiment.

FIG. 10 is a rear view of the mirror case with the mirror removed from the mirror case in the modified example.

FIG. 11 is a sectional view taken along the line 11-11 in FIG. 10;

[Explanation of symbols]

10 ... Light emitting circuit, 20 ... Laser emitting device, 20
a ... Mirror drive mechanism, 21 ... Base, 22 ...
Idol gear train, 26 ... Mirror case, 29 ...
Mirror, 30 ... Light receiving lens, 60 ... Microcomputer, 70 ... Driving circuit, S, Sa ... Stopper.

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location G01S 17/02 G01S 17/02 Z

Claims (2)

[Claims] 1. A beam light emitting means (10, 20) for emitting a beam light by reflecting it by a mirror, and detecting the obstacle based on the reflected beam light when the emitted beam light is reflected by an obstacle. Detection means (3
0, 40, 50), the beam light emitting means has a step motor (25) for rotating the mirror, and the step so that the mirror reciprocates within a predetermined rotation range. Drive control means for driving and controlling the motor (6
0, 70), and the drive control means controls the turning position of the step motor so as to match the turning position of the mirror with the initial position when starting the obstacle detection. 2. The obstacle detection system according to claim 1, wherein the initial position is a position corresponding to one side turning end of the mirror.