Vehicle with road surface condition detector

A vehicle includes: a vehicle body; front and rear wheels configured to move the vehicle body; and a road surface condition detector configured to detect road surface conditions in front of each of the front wheels, wherein the road surface condition detector is positioned in front of each of the front wheels, and a direction of radiating laser beams by the road surface condition detector for detecting a detection point on a road surface is inclined in a direction of a tangent to an arc, about a pitch center of the vehicle body and running through the detection point, at the detection point, when the vehicle body is viewed laterally.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority to Japanese Patent Application No. 2021-038070 filed on Mar. 10, 2021, the disclosures of all of which are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The present invention relates to a vehicle with a road surface condition detector.

BACKGROUND OF THE INVENTION

A conventional vehicle detects conditions of a road surface to be followed by wheels, to control the vehicle for comfortable riding. There are two methods of detecting road surface conditions by a conventional road surface condition detection sensor. First one is to mount a sensor at above a front window, to detect road surface conditions in front of the vehicle. Second one is to mount a sensor at a bumper, to detect road surface conditions right below the vehicle.

For example, in Japanese Patent Application Publication No. 2013-205196 (hereinafter, referred to as Patent Document 1; see FIGS. 1 to 4, paragraphs 0015, 0016), a projector 12 and a camera 18, provided in vicinity to a front bumper, are used to estimate road surface conditions in front of a vehicle 10. According to the disclosure, the projector 12 uses a projection controller 24 to control on-off of projecting a reference pattern or adjust radiation intensity depending on environmental conditions.

SUMMARY OF THE INVENTION

Problems to be Solved

However, with the invention of Patent Document 1, detection points on the road surface are displaced in a front-rear direction when the vehicle experiences a pitching motion. In this case, there is a change in a distance between the detection points and wheels, to have a risk of having an error. For example, there can be a difference between said distance, when a sensor has detected a hubbly road surface, and said distance, when the wheels run over the hubbly road surface, even with the vehicle traveling at the same speed, and this leads to a gap in traveling time to cause an error when an electromagnetic damper of a suspension is controlled. The distance between the detection points and the wheels thus need to be corrected with control thereover. In other words, calculations need to be done to correct the error.

In contrast, in a case where a sensor is mounted at a bumper to detect points right below a vehicle, changes in a distance from wheels to road surface detection points are smaller than those in Patent Document 1, when the vehicle experiences a pitching motion, but there is still an error. The present invention has been invented in view of above-described situations, and is intended to provide a vehicle with an error, in changes in a distance between road surface detection points and wheels, reduced to improve controllability.

Solution to Problem

In order to solve the above-identified problem, a vehicle with a road surface condition detector according to a first aspect of the present invention includes: a vehicle body; front and rear wheels configured to move the vehicle body; and a road surface condition detector configured to detect road surface conditions in front of each of the front wheels, wherein the road surface condition detector is positioned in front of each of the front wheels, and a direction of radiating laser beams by the road surface condition detector for detecting a detection point on a road surface is inclined in a direction of a tangent to an arc, about a pitch center of the vehicle body and running through the detection point, at the detection point, when the vehicle body is viewed laterally.

A vehicle with a road surface condition detector according to a second aspect of the present invention includes: a vehicle body; front and rear wheels configured to move the vehicle body; and a road surface condition detector configured to detect road surface conditions in front of each of the rear wheels, wherein the road surface condition detector is positioned in front of each of the rear wheels, and a direction of radiating laser beams by the road surface condition detector for detecting a detection point on a road surface is inclined in a direction of a tangent to an arc, about a pitch center of the vehicle body and running through the detection point, at the detection point, when the vehicle body is viewed laterally.

Advantageous Effects of the Invention

The present invention provides a vehicle with an error, in changes in a distance between a detection point on a road surface and wheels, reduced to improve controllability.

EMBODIMENTS OF THE INVENTION

Hereinafter, a description is given in detail of an embodiment of the present invention, with reference to the drawings as required.FIG.1Ais a conceptual side view of a vehicle1according to an embodiment of the present invention, andFIG.1Bis a perspective view of the vehicle1according to the embodiment. The present invention relates to a sensing direction for detecting road conditions by preview sensors5f,5rof the vehicle1. The preview sensors5f,5ruse laser beams or the like for the detection. The vehicle1of the present embodiment includes a right front wheel2rand a left front wheel2l, as steering wheels to change a moving direction of the vehicle1, at a front thereof. The vehicle1includes a right rear wheel3rand a left rear wheel3l, as driven wheels or driving wheels, at a rear thereof.

A vehicle body1hsupported by the wheels2r,2l,3r,3lof the vehicle1is configured to have one or more passengers therein. The vehicle1is provided, on a front thereof, with a headlight3hto irradiate a road surface R to come, and is provided, on a rear thereof, with a rear light3ato irradiate the road surface R to go. The vehicle1is also provided, at a front and a rear thereof, with a front bumper4fand a rear bumper4reach configured to absorb impact from a collision at the front or the rear.

The vehicle1has the preview sensor5fprovided at a position overlapping with the right front wheel2r, when viewed from front, as shown inFIG.1B. The vehicle1also has the preview sensor5fprovided at a position overlapping with the left front wheel2l, when viewed from front. The preview sensors5fare provided at positions without any misalignment in a vehicle width direction with respect to, and overlapping with, the front wheels2r,2l, respectively, as viewed from front. This allows for more precisely detecting conditions of a road surface to be followed by the front wheels2r,2l.

Likewise, the vehicle1has the preview sensor5rprovided at a position overlapping with the right rear wheel3r, when viewed from front. The vehicle1also has the preview sensor5rprovided at a position overlapping with the left rear wheel3l, when viewed from front. The preview sensors5rare provided at positions without any misalignment in a vehicle width direction with respect to, and overlapping with, the rear wheels3r,3l, respectively, as viewed from front. This allows for more precisely detecting road surface conditions followed by the rear wheels3r,3l. Used as the preview sensors5f,5rare sensors such as radars, cameras, and laser devices, or other sensors. The preview sensors5f,5rcan be any sensors as far as they can detect road surface conditions.

A description is given of the embodiment with sensors using laser devices, as the preview sensors5f,5r, by way of example. For detecting conditions of the road surface R, the preview sensors5f,5rare configured to radiate laser beams rb toward the road surface R (seeFIG.1A), as described below, to detect a distance therefrom to the road surface (road surface condition).

The vehicle1(vehicle body1h) has a pitch center c with respect to the road surface R, when the vehicle1is in a standstill as shown inFIG.1A.FIG.2is a conceptual side view of the vehicle1according to the embodiment to show positional relationships between the pitch center c, the front wheels2r,2l, and detection points5s,5sron the road surface R detected by the preview sensors5f,5r. An arc c1is drawn about the pitch center c of the vehicle1, so as to run through the detection point5son the road surface R irradiated with the laser beams rb from the preview sensors5f. A tangent c1sis then drawn to the arc c1at the detection point5s.

The direction of radiating the laser beams rb is set in this manner, when the vehicle1is in a standstill, to that of the tangent c1sto the arc c1at the detection point5s. In other words, the direction of radiating the laser beams rb from the preview sensors5fis set, when the vehicle1is in a standstill as shown inFIG.1A, to that of the tangent c1sto the arc c1, about the pitch center c of the vehicle1and running through the detection point5s, at the detection point5s.

That is, the direction of radiating the laser beams rb from the preview sensors5fis inclined in that of the tangent to the arc c1, about the pitch center c of the vehicle1, at the detection point5s. In other words, the direction of radiating the laser beams rb from the preview sensors5fis in line with that of the tangent c1sto the arc c1, about the pitch center c of the vehicle1, at the detection point5s. This causes the vehicle1to have the direction of radiating the laser beams rb for detecting conditions of the road surface R set to that of the tangent to the arc c1, about the pitch center c, at the detection point5s, to detect conditions of the road surface R.

Likewise, an arc c2is drawn about the pitch center c of the vehicle1, so as to run through the detection point5son the road surface R irradiated with the laser beams rb from the preview sensors5r. A tangent c2sis then drawn to the arc c2at the detection point5sr.

The direction of radiating the laser beams rb is set in this manner, when the vehicle1is in a standstill, to that of the tangent c2sto the arc c2at the detection point5sr. In other words, the direction of radiating the laser beams rb from the preview sensors5ris set, when the vehicle1is in a standstill as shown inFIG.1A, to that of the tangent c2sto the arc c2, about the pitch center c of the vehicle1, at the detection point5sr.

That is, the direction of radiating the laser beams rb from the preview sensors5ris inclined in that of the tangent to the arc c2, about the pitch center c of the vehicle1, at the detection point5sr. In other words, the direction of radiating the laser beams rb from the preview sensors5ris in line with that of the tangent c2sto the arc c2, about the pitch center c of the vehicle1, at the detection point5sr. This causes the vehicle1to have the direction of radiating the laser beams rb for detecting conditions of the road surface R set to that of the tangent to the arc c2, about the pitch center c, at the detection point5sr, to detect conditions of the road surface R.

Here, the rear preview sensor5rexecutes detection in the same manner as the front preview sensor5f. Then, the preview sensor5fis described below, but a description of the preview sensor5ris omitted.

Change in Distance from Front Wheel to Detection Point on Road Surface, when Vehicle of Comparative Example 1 Experiences Pitching Motion

Descriptions are given below of Comparative Examples 1, 2.FIG.3Ais a conceptual side view of a vehicle101having a road surface condition detection sensor105of Comparative Example 1, to show a relationship between the vehicle101and a detection point r0on the road surface R detected by the road surface condition detection sensor105.FIG.3Bis a conceptual side view of the vehicle101of Comparative Example 1, to show displacement of a detection point r0on the road surface R detected by the road surface condition detection sensor105, when the vehicle1experiences a pitching motion.

The vehicle101of Comparative Example 1 has the road surface condition detection sensor105mounted at above a front window101a, as shown inFIG.3A. The vehicle101has the detection point r0set on the road surface R, to be detected by the road surface condition detection sensor105when the vehicle101is in a standstill. The road surface condition detection sensor105uses the laser beams rb to detect the detection point r0on the road surface R in front of the vehicle101for detecting road surface conditions. In this case, a distance from front wheels102r,102lto the detection point r0, as a detected road surface position, is s0.

With the vehicle101experiencing a pitching motion about a pitch center101c, the detection point r0detected by the road surface condition detection sensor105displaces in a range between a detection point r1and a detection point r2, as shown inFIG.3B. This causes the distance s0to be changed between a distance s1to the detection point r1, as a detected road surface position, and a distance s2to the detection point r2, as a detected road surface position, from the front wheels102r,102l. Thus, in order to detect road surface conditions for accurate control, correction is required for a distance between the distance s1to the detection point r1, as a detected road surface position, and the distance s2to the detection point s2a, as a detected road surface position, from the front wheels102r,102l, based on a difference from the distance s0at the detection point r0.

Change in Distance from Front Wheel to Detection Point on Road Surface, when Vehicle of Comparative Example 2 Experiences Pitching Motion

FIG.4is a conceptual side view of a vehicle201having a road surface condition detection sensor205of Comparative Example 2, to show a relationship between the vehicle201and a detection point r10on the road surface R detected by the road surface condition detection sensor205. The vehicle201of Comparative Example 2 has the road surface condition detection sensor205mounted at a front bumper204f, to detect the road surface R right therebelow.

The road surface condition detection sensor205is configured to use the laser beams rb to detect the detection point r10on the road surface R right below the vehicle201.FIG.5Ais a conceptual side view of the vehicle201of Comparative Example 2, to show displacement of the detection point r10on the road surface R detected by the road surface condition detection sensor205, when the vehicle201experiences a pitching motion, andFIG.5Bis an enlarged side view to show positional relationships between detection points r11, r12and front wheel202r,202linFIG.5Afor Comparative Example 2.

With the vehicle201of Comparative Example 2 experiencing a pitching motion about a pitch center201c, as shown inFIG.5A, the detection point r10detected by the road surface condition detection sensor205, when the vehicle201is in a standstill, displaces in a range between a detection point r11and a detection point r12, as shown inFIG.3B. This causes a distance s10from the front wheels202r,202lto the detection point r10, as a detected road surface position, to be changed between a distance s11to the detection point r11, as a detected road surface position, and a distance s12to the detection point r12, as a detected road surface position, from the front wheels202r,202l.

Thus, in order to detect road surface conditions for accurate control, correction is required for a distance between the distance s11to the detection point r11, as a detected road surface position, and the distance s12to the detection point s12, as a detected road surface position, from the front wheels202r,202l, based on a difference from the distance s10at the detection point r10.

Change in Distance from Front Wheel to Detection Point, when Vehicle of Present Embodiment Experiences Pitching Motion

In contrast to Comparative Examples 1 and 2 as described above, the vehicle1of the present embodiment has a direction of radiating the laser beams rb, when obtaining information on conditions of the road surface R from the preview sensor5f, set in line with the direction of the tangent c1sto the arc c1, about the pitch center c of the vehicle1, at the detection point5son the arc c1, when the vehicle1(vehicle body1h) in a standstill is viewed laterally. In other words, the direction of radiating the laser beams rb from the preview sensor5fis orthogonal to a line (bold chain line inFIG.2) connecting the detection point5son the arc about the pitch center c of the vehicle1with the pitch center c.

The preview sensors5fare mounted in front of the front wheels2r,2lof the vehicle body1hat positions overlapping with the front wheels2r,2l, as viewed from front, as shown inFIGS.1A,1B.FIG.6Ais a conceptual side view of the vehicle1according to the embodiment, experiencing a pitching motion about the pitch center c, andFIG.6Bis a conceptual side view of the vehicle1according to the embodiment, experiencing a pitching motion, to show positional relationships between the pitch center c, the front wheel2r,2l, and the detection point5sdetected by the preview sensor5f.

When the vehicle1experiences a pitching motion due to conditions of the road surface R, the vehicle body1hexperiences a pitching motion about the pitch center c, as shown inFIG.6A. The preview sensor5fmounted to the vehicle body1halso experiences a pitching motion about the pitch center c. For example, when the road surface R changes to a downhill road surface R1with respect to the vehicle body1h, the detection point5sis displaced to a detection point5s1on the road surface R1, as shown inFIG.6B. At this time, the preview sensor5fpivots downward about the pitch center c to a position indicated as a preview sensor5a. However, the front wheels2r,2lexperience a pitching motion about the pitch center c and thus there is no change in distances between the front wheels2r,2land the pitch center c.

When the entire vehicle1experiences a pitching motion about the pitch center c so as to take a dive, a displacement of the detection point5son the road surface R, due to the pitching motion, to the detection point5s1on the road surface R1is minimal, with respect to the arc c1about the pitch center c. Likewise, when the road surface R changes to an uphill road surface R2with respect to the vehicle body1h, the detection point5sis displaced to a detection point5s2on the road surface R2. At this time, the preview sensor5fpivots upward about the pitch center c to a position indicated as a preview sensor5b. However, the front wheels2r,2lexperience a pitching motion about the pitch center c so as to be raised, and thus there is no change in distances between the front wheels2r,2land the pitch center c.

When the entire vehicle1experiences a pitching motion about the pitch center c so as to take a squat, a displacement of the detection point5son the road surface R, due to the pitching motion, to the detection point5s2on the road surface R2is minimal, with respect to the arc c1about the pitch center c.

FIG.7Ais a conceptual side view of the vehicle traveling on an uphill road surface Rn, andFIG.7Bis a conceptual side view of the vehicle1traveling on the uphill road surface Rn, to show positional relationships between the pitch center c, the front wheels2r,2l, and the detection point5sdetected by the preview sensor5f.

When the vehicle1is traveling on the uphill road surface Rn, as shown inFIG.7A, the preview sensor5f(seeFIGS.1A,1B), mounted on the vehicle body1hon the flat road surface R, is displaced to a position indicated as the preview sensor5a, as shown inFIG.7B. A detection point5s3(seeFIG.7B) is the point detected by the preview sensor5aon the uphill road surface Rn. When the road surface is the uphill road surface Rn, the vehicle1takes a squat. In this case, the positional relationships with the pitch center c and front wheels2r,2lof the vehicle body1hare substantially not changed, as shown inFIG.7B, between at the detection point5son the flat road surface R, detected by the preview sensor5f, and at the detection point5s3on the uphill road surface Rn, detected by the preview sensor5a.

Also when the vehicle1is traveling on a downhill road surface, the positional relationships with the pitch center c and front wheels2r,2lof the vehicle body1hare substantially not changed, as inFIG.7B, between at the detection point on the downhill road surface, detected by the displaced preview sensor5f, and at the detection point5son the flat road surface R, detected by the preview sensor5f. When the vehicle1travels on an inclined road surface, the vehicle1takes a squat or takes a dive, but the positional relationships from the detection point5s3on the uphill road surface Rn to the front wheels2r,2lremain substantially the same as those when the vehicle1travels on a flat road surface. As a result, when the vehicle1according to the embodiment experiences a pitching motion, the positional relationships between the detection point5s(5s1,5s2) and the front wheels2r,2lare substantially not changed, as compared with Comparative Example 1 inFIG.3Band Comparative Example 2 inFIG.5B.

According to the above-described embodiment, the direction of radiating the laser beams rb from the preview sensors5fis inclined in that of the tangent to the arc c1, about the pitch center c of the vehicle1, at the detection point5s, as shown inFIGS.1A and2. Accordingly, even when the vehicle1experiences a pitching motion or travels on the inclined road surface Rn, as shown inFIGS.7A and7B, an error in changes in a distance between the detection point5s1,5s2, or5s3on the road surface R or Rn and the front wheels2r,2lis reduced to improve controllability. In addition, no need of correcting an error, in changes in a distance between the detection point5s1,5s2, or5s3on the road surface R or Rn and the front wheels2r,2l, reduces a load in calculation.

Likewise, the direction of radiating the laser beams rb from the preview sensors5ris inclined in that of the tangent to the arc c2, about the pitch center c of the vehicle1, at the detection point5sr, as shown inFIG.1A. Accordingly, even when the vehicle1experiences a pitching motion or travels on the inclined road surface Rn, as inFIG.7B, an error in changes in a distance between a detection point on the road surface R or Rn and the rear wheels3r,3lis reduced to improve controllability.

In addition, no need of correcting an error, in changes in a distance between the detection point on the road surface R or Rn and the rear wheels3r,3l, reduces a load in calculation.

Modifications

The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of appended claims

LIST OF REFERENCE SIGNS