Vehicle wheel assembly position measurement method and apparatus thereof

A vehicle wheel assembly position measurement method for measuring a height position of a wheel assembly relative to a vehicle body, the vehicle wheel assembly position measurement method comprising:

• a distance measurement step of measuring a distance in a vehicle width direction between each of plural measurement points and a distance measuring instrument at at least three measurement positions in a circumferential direction on a lateral surface of a tire section of the wheel assembly, the distance measuring instrument being arranged on a lateral side of each of the measurement positions, and each of the plural measurement points being located on a specified line that crosses the lateral surface of the tire section from an inner circumferential end to an outer circumferential end;
• a vehicle body position measurement step of measuring a height position of a specified portion of the vehicle body by a vehicle body position measuring instrument;
• an approximate curve calculation step of calculating, at each of the measurement positions, an approximate curve in a graph on the basis of measurement data of each of the measurement points, at which the distance on the specified line is measured, a relationship between a position in an extending direction of the specified line and the distance of the respective measurement point being plotted in the graph;
• a rotation center position calculation step of calculating a rotation center position of the wheel assembly from a specific position on the approximate curve at each of the at least three measurement positions;
• and
• a wheel assembly height position calculation step of calculating the height position of the wheel assembly relative to the vehicle body from the rotation center position calculated in the rotation center position calculation step and the height position of the specified portion of the vehicle body measured in the vehicle body position measurement step.