Wheel alignment measuring instrument and wheel alignment measuring

A wheel alignment measuring device for measuring the distance from and the inclination of the measuring surface of a measured plate which is attached to a wheel of a vehicle being measured so that the origin thereof corresponds to the center of the rotational axis of the wheel, comprising:

• said wheel alignment measuring device comprises at least four distance measuring light emitting and receiving means having light emitting portions which are arranged on a same virtual plane at predetermined intervals for emitting distance measuring light onto the measuring surface, receiving the distance measuring light reflected by the measuring surface, and outputting distance measuring signals,
• said light emitting portions being so arranged on the same virtual plane at intervals that the distance measuring light emitted from at least three of the at least four distance measuring light emitting and receiving means impinges on the measuring surface under predetermined measuring conditions,
• the virtual plane is arranged so that it contains a straight line substantially in parallel with a vertical direction of the vehicle to be measured,
• a virtual parallelogram being arranged on the virtual plane so that the straight line includes one of the diagonal lines of the virtual parallelogram,
• the light emitting portions of the at least four distance measuring light emitting and receiving means are arranged at each corner of the virtual parallelogram, and
• the virtual parallelogram is arranged so that the distance measuring light is emitted from the two light emitting portions on the other diagonal line not included in the straight line within a common area for a first measuring surface corresponding to a maximum distance moved by the measuring surface in a first direction along the straight line, and a second measuring surface corresponding to a maximum distance moved by the measuring surface in a second direction opposite to the first direction.

A wheel alignment measuring method for measuring, by employing a measuring plate attached coaxially with a rotary axis of a wheel, a distance from a measuring surface of the measuring plate, and an angle of inclination of the measuring surface, comprising the steps of:

• emitting at least three out of at least four distance measuring light beams spaced at predetermined intervals onto the measuring surface and receiving the distance measuring light beams reflected therefrom;
• and
• calculating a camber angle of the measuring surface based on the received distance measuring light beams,
• a virtual plane being arranged so that it includes a straight line substantially in parallel with the vertical direction of the vehicle to be measured,
• the step of distance measuring light emitting and receiving being implemented by arranging a virtual parallelogram on the virtual plane so that the straight line includes one of the diagonal lines of the virtual parallelogram, emitting the distance measuring light beams from each apex of the virtual parallelogram and receiving the distance measuring light beams reflected at the measuring surface,
• the step of calculating camber angle being implemented by receiving reflected distance measuring light beams emitted from two apexes on the other diagonal line not included in the straight line onto a common area for a first measuring surface corresponding to a maximum distance moved by the measuring surface in a first direction along the straight line, and a second measuring surface corresponding to a maximum distance moved by the measuring surface in a second direction opposite to the first direction and by receiving reflected distance measuring light beam emitted from either one of apexes on the diagonal line included in the straight line onto the measuring surface.

A caster angle measuring device comprising:

• a wheel alignment measuring plate having a measuring object thereon;
• a CCD camera for picking up an image of the wheel alignment measuring target plate;
• original caster angle data calculating means for calculating original caster angle data θ CAS by quantizing a caster angle formed between a measuring object line and a predetermined reference line based on the image data;
• and
• output means for outputting the original caster angle data θ CAS as the effective caster angle data θ ECAS when the original caster angle data θ CAS changes its value.

A wheel alignment measuring device comprising:

• a CCD camera for outputting image data by picking up an image of a caster angle measuring object line provided on a wheel alignment measuring target plate attached to a vehicle;
• a caster angle measuring device for outputting effective caster angle data θECAS having a desired measuring accuracy based on the image data obtained by picking up an image, with use of the external CCD camera, of the caster angle measuring object line, comprising:
• original caster angle data calculating means for calculating original caster angle data θ CAS by quantizing the caster angle formed between the measuring object line and a predetermined reference line based on the image data;
• and
• effective data output means for outputting the original caster angle data θ CAS as the effective caster angle data θ ECAS when the original caster angle data θ CAS changes its value and
• data comparing means for comparing the effective caster angle data θ ECAS with measured data of a different dimension at substantially the same time when there is said change in the original caster angle data θCAS.

A caster angle measuring device for outputting effective caster angle data θ ECAS having a desired measuring accuracy based on image data obtained by picking up an image with use of an external CCD camera, of a caster angle measuring object line provided on a wheel alignment measuring target plate mounted on a vehicle, comprising:

• original caster angle data calculating means for calculating original caster angle data θ CAS based on the image data when the caster angle formed between the measuring object line and a predetermined reference line changes continuously in either direction of increasing or decreasing;
• comparing means for comparing original caster angle data θ CAS(n−1) measured in a previous measurement timing with original caster angle data θ CAS(n) measured in a current measurement timing;
• and
• effective data output means for outputting the original caster angle data θ CAS(n) of the current measurement as the effective caster angle data θ ECAS when the comparison results in:
• θ CAS(n−1)≠θ CAS(n).

A wheel alignment measuring device comprising:

• a CCD camera for outputting image data by picking up an image of a caster angle measuring object line drawn on a wheel alignment measuring target plate attached to a vehicle;
• a caster angle measuring device for outputting effective caster angle data θ ECAS having a desired measuring accuracy based on image data obtained by picking up an image, with use of the external CCD camera, of the caster angle measuring object line, comprising:
• original caster agile data calculating means for calculating original caster angle data θ CAS based on the image data when the caster angle formed between the measuring object line and a predetermined reference line changes continuously in either direction of increasing or decreasing;
• comparing means for comparing original caster angle data θCAS(n−1) measured in a previous measurement timing with original caster angle data θCAS(n) measured in a current measurement timing;
• and
• effective data output means for outputting the original caster angle data θ CAS(n) of the current measurement as the effective caster angle data θ ECAS when the comparison results in:
• θ CAS(n−1)≠θ CAS(n);
• and
• data comparing means for comparing the current original caster angle data θ CAS(n) with measured data of a different dimension at substantially the same time as the measurement of the current original caster angle data θ CAS(n).

A caster angle measuring method for calculating an effective caster angle θ ECAS having a desired measuring accuracy based on image data obtained by picking up an image, with use of an external CCD camera of a caster angle measuring object line provided on a wheel alignment measuring target plate attached to a vehicle, comprising the steps of:

• calculating an original caster angle θ CAS based on the image data when the caster angle formed between the measuring object line and a predetermined reference line changes continuously in either direction of increasing or decreasing;
• comparing an original caster angle θ CAS(n−1) measured in a previous measurement timing with an original caster angle θ CAS(n) measured in a current measurement timing;
• and
• judging the current original caster angle θ CAS(n) to use as an effective caster angle θ ECAS when the comparison results in:
• θ CAS(n−1)≠θ CAS(n).

A wheel alignment measuring method comprising the steps of:

• picking up an image of a caster angle measuring object line provided on a wheel alignment measuring target plate attached to a vehicle;
• calculating an original caster angle θ CAS by quantizing the caster angle formed between the picked-up measuring object line and a predetermined reference line;
• judging the original caster angle θ CAS to use as the effective caster angle θ ECAS when the caster angle θ CAS changes its value;
• and
• comparing the effective caster angle θ ECAS with measured data of a different dimension at substantially the same time when there is said change in the original caster angle θ CAS.

A wheel alignment measuring method comprising the steps of:

• picking up an image of a caster angle measuring object line provided on a wheel alignment measuring target plate attached to a vehicle;
• calculating an original caster angle θ CAS when the caster angle formed between the picked-up measuring object line and a predetermined reference line changes continuously in either direction of increasing or decreasing;
• comparing an original caster angle θ CAS(n−1) measured in a previous measurement timing with an original caster angle θ CAS(n) measured in a current measurement timing;
• judging the current original caster angle θ CAS(n) to use as an effective caster angle θ ECAS when the comparison results in:
• θ CAS(n−1)≠θ CAS(n);
• and
• comparing the current original caster angle θ CAS(n) with measured data of a different dimension at substantially the same time as a timing of the measurement of the current original caster angle θCAS(n).

A wheel alignment measuring device for measuring wheel alignment comprising:

• a measuring plate configured to be attached to a vehicle wheel with its origin of coordinate being coincide with the center of the wheel, said measuring plate comprising:
• a first reference mark having its origin of coordinate at a predetermined position;
• a plurality of second reference marks having their origins of coordinates at intersections, except the position of the first reference mark, of first virtual parallel lines provided hypothetically on a measuring surface and second virtual parallel lines provided hypothetically on the measuring surface at right angles to the first virtual lines;
• and
• a plurality of correction lines being provided on the measuring surface at regular intervals and in parallel with either the first virtual lines or the second virtual lines;
• first image pick-up means for outputting a first picked-up image signal by taking a picture of a first area including said first reference mark and said plurality of second reference marks on said measuring surface of the measuring plate;
• second image pick-up means for outputting a second picked-up image signal by taking a picture of a second area which is smaller than the first area and included in the first area, said second image pick-up means having an optical axis positionally related beforehand with an optical axis of said first image pick-up means;
• selecting means for selecting one of said second reference marks within said second area as a selected second reference mark based on the second picked-up image signal;
• relative reference position calculating means for calculating coordinates of relative reference position on the basis of the position coordinates of the selected second reference mark by specifying said selected second reference mark within said first area based on the first picked-up image signal;
• and
• position calculating means for calculating reference position coordinates of the origin of position given by a predetermined position within the second area based on the second picked-up image signal and the relative reference position coordinates.

A wheel alignment measuring method for measuring wheel alignment comprising the steps of:

• providing a measuring plate configured to be attached to a vehicle wheel with its origin of coordinate being coincide with the center of the wheel, said measuring plate comprising:
• a first reference mark having its origin of coordinate at a predetermined position;
• a plurality of second reference marks having their origins of coordinates at intersections, except the position of the first reference mark, of first virtual parallel lines provided hypothetically on a measuring surface and second virtual parallel lines provided hypothetically on the measuring surface at right angles to the first virtual lines;
• and
• a plurality of correction lines being provided on the measuring surface at regular intervals and in parallel with either the first virtual lines or the second virtual lines;
• picking up an image of a first area containing the first reference mark and the plurality of second reference marks on the measuring surface of said measuring plate;
• picking up an image of a second area having smaller area than that of the first area and included in the first area;
• selecting any one of the second reference marks within the second area to use as a selected second reference mark;
• specifying said selected second reference mark within the first area and calculating position coordinates of said selected second reference mark to use as relative reference position coordinates;
• and
• calculating reference position coordinates of the origin of position which are position coordinates on the basis of the origin of a predetermined position in the second area, based on the relative reference position coordinates.