Vehicle wheel alignment by rotating vision sensor

A method comprising:

• during a first measurement cycle, obtaining spatial coordinates of a plurality of points on a wheel to be characterized by positioning a vision sensor at a plurality of angular offsets relative to the wheel, the plurality of points sampled from each of the plurality of angular offsets;
• rotating the wheel from a first position to a second position between the first measurement cycle and a second measurement cycle, by moving a plate underneath the wheel with which the wheel interfaces;
• during the second measurement cycle, obtaining spatial coordinates of a plurality of points on the wheel by positioning the vision sensor at a plurality of angular offsets relative to the wheel, the plurality of points sampled from each of the plurality of angular offsets;
• and
• determining one or more characteristics of the wheel based upon the spatial coordinates collected during the first measurement cycle and the spatial coordinates collected during the second measurement cycle.

An apparatus comprising:

• a sensor means, having a field of vision, for determining spatial coordinates of a group of points within the field of vision;
• a means for rotating the vision sensor through a plurality of angular positions with respect to a wheel of a vehicle to be characterized during a first measurement cycle and a second measurement cycle so that the fields of vision associated with the plurality of angular positions together form at least a portion of a torus;
• a positional recording means for collecting, for each of the plurality of angular positions, spatial coordinates of a plurality of points located on a surface of the wheel and within the torus during the first measurement cycle and for collecting, for each of the plurality of angular positions, spatial coordinates of a plurality of points located on the surface and within the torus during the second measurement cycle;
• a means for maintaining the vehicle in substantially the same position while rotating the wheel from a first position to a second position between the first measurement cycle and the second measurement cycle;
• and
• a means for determining one or more characteristics of the wheel based upon the spatial coordinates collected during the first measurement cycle and the spatial coordinates collected during the second measurement cycle.

A method comprising:

• during a first measurement cycle, a step for obtaining spatial coordinates of a plurality of points on a wheel to be characterized by positioning a vision sensor at a plurality of angular offsets relative to the wheel, each of the plurality of points corresponding to a different one of the plurality of angular offsets;
• a step for rotating the wheel from a first position to a second position between the first measurement cycle and a second measurement cycle by a movement of a plate underneath the wheel;
• during the second measurement cycle, a step for obtaining spatial coordinates of a plurality of points on the wheel by positioning the vision sensor at a plurality of angular offsets relative to the wheel, each of the plurality of points corresponding to a different one of the plurality of angular offsets;
• and
• a step for determining one or more characteristics of the wheel based upon the spatial coordinates collected during the first measurement cycle and the spatial coordinates collected during the second measurement cycle.

A method comprising:

• during a first measurement cycle, obtaining spatial coordinates of a plurality of points on a wheel to be characterized by positioning a single movable vision sensor at a plurality of angular offset relative to the wheel, the plurality of points sampled from each of the plurality of angular offsets;
• rotating the wheel from a first position to a second position between the first measurement cycle and a second measurement cycle, by moving a plate underneath the wheel with which the wheel interfaces;
• during the second measurement cycle, obtaining spatial coordinates of a plurality of points on the wheel by positioning the single moveable vision sensor at a plurality of angular offsets relative to the wheel, the plurality of points sampled from each of the plurality of angular offsets;
• and determining one or more characteristics of the wheel based upon the spatial coordinates collected during the first measurement cycle and the spatial coordinates collected during the second measurement cycle.

A method comprising:

• determining a first set of measurements from which a first approximation of a plane of a wheel of a vehicle may be derived by periodically measuring a distance from a vision sensor to a surface of the wheel at a plurality of angular positions while rotating the vision sensor in a substantially circular arc relative to the wheel;
• rotating the wheel a predetermined angle about an axis of the wheel by expanding or contracting a hydraulic or pneumatic ram coupled to a moveable plate upon which the wheel rests;
• determining a second set of measurement from which a second approximation of the plane of the wheel may be derived by periodically measuring the distance from the vision sensor to the surface while again rotating the vision sensor relative to the wheel;
• and
• determining one or more alignment characteristics of the wheel based on the first set of measurements and the second set of measurements by removing an error competent contributing to inaccuracy of the first approximation of the plane of the wheel and the second approximation of the plane of the wheel.

A wheel alignment system comprising:

• a platform to support a vehicle;
• a vision sensor associated with the platform, the vision sensor having a field of vision and capable of determining spatial coordinates of a group of points within the field of vision:
• a motor coupled to the vision sensor to rotate the vision sensor through a plurality of angular positions with respect to a wheel of the vehicle to be characterized during a first measurement cycle and a second measurement cycle so that the fields of vision associated with the plurality of angular positions together form at least a portion of a torus;
• a positional recorder associated with the vision sensor to collect, for each of the plurality of angular positions, spatial coordinates of a plurality of points located on a surface of the wheel and within the torus during the first measurement cycle and to collect, for each of the plurality of angular positions, spatial coordinates of a plurality of points located on the surface and within the torus during the second measurement cycle;
• at least one inclined moveable plate moveably attached to the platform, the at least one inclined moveable plate configured to interface with the wheel and rotate the wheel from a first position to a second position between the first measurement cycle and second measurement cycle by expanding or contracting a hydraulic or pneumatic ram coupled to the at least one included moveable plate ans the platform;
• and
• a computer to determine one or more characteristics of the wheel based upon the spatial coordinates collected during the first measurement cycle and the spatial coordinates collected during the second measurement cycle.