Laser tracking wheel alignment measurement apparatus and method

A method for determining the actual rotational plane of at least two wheels of a vehicle in a common coordinate system, comprising the steps of:

• locating a first response member on a first of said wheels;
• locating a second response member on a second of said wheels;
• rotating said first wheel about its central axis of rotation while the vehicle is in a natural loaded driving condition;
• rotating said second wheel about its central axis of rotation while the vehicle is in a natural loaded driving condition;
• tracking the position of said first and second response members respectively in three dimensional space during the rotation of said first and second wheels by directing a light beam at said responsive member capable of accurately following the movement of said responsive member;
• generating a first signal directly representative of the actual rotational plane of said first wheel;
• and
• generating a second signal directly representative of the actual rotational plane of said second wheel.

A method for determining the actual rotational plane of each of four wheels of a vehicle in a common coordinate system, comprising the steps of:

• affixing a first reflective device to a first of said four wheels at any point on said first wheel offset from the central axis of rotation of said first wheel;
• affixing a second reflective device to second of said four wheels at any point on said second wheel offset from the central axis of rotation of said second wheel;
• affixing a third reflective device to a third of said four wheels at any point on said third wheel offset from the central axis of rotation of said third wheel;
• affixing a fourth reflective device to fourth of said four wheels at any point on said fourth wheel offset from the central axis of rotation of said four wheel;
• rotating said first, second, third and fourth wheels about each of their respective central axes of rotation while the vehicle is in a natural, loaded driving condition;
• tracking the position of said first, second, third and fourth reflective devices respectively in three dimensional space during the rotation of said wheels by directing a light beam at each said respective reflective device capable of accurately following the movement of said respective reflective device;
• generating a first signal directly representative of the actual rotational plane of said first wheel;
• generating a second signal directly representative of the actual rotational plane of said second wheel;
• generating a third signal directly representative of the actual rotational plane of said third wheel;
• and
• generating a fourth signal directly representative of the actual rotational plane of said fourth wheel.

A method for determining the actual rotational plane of at least two wheels of a vehicle in a common coordinate system, comprising the steps of:

• affixing a first reflective device to a first of said at least two wheels at any point on said wheel offset from the central axis of rotation of said first wheel;
• affixing a second reflective device to second of said at least two wheels at any point on said other wheel offset from the central axis of rotation of said second wheel;
• rotating said first wheel about its central axis of rotation by driving the vehicle in any natural loaded driving condition;
• rotating said second wheel about its central axis of rotation by driving the vehicle in any natural loaded driving condition;
• tracking the position of said first and second reflective devices respectively in three dimensional space by directing a light beam at said reflective device capable of accurately following the movement of said reflective device;
• generating a first signal directly representative of the actual rotational plane of said first wheel;
• and
• generating a second signal directly representative of the actual rotational plane of said second wheel.

An apparatus for measuring the natural rotational plane of a wheel comprising:

• a reflective device affixable to said wheel;
• a laser tracking device adapted to track the movements of said reflective device in three dimensional space while the wheel is in a natural loaded driving condition during the rotation of said wheel and generating a signal directly representative of the actual rotational plane of said wheel;
• and
• a processor for receiving said signal and comparing said signal to a electronically stored mathematical model to determine wheel alignment conditions.