Apparatus and method for maintaining wheel alignment sensor runout compensation
AssigneeHunter Engineering Company
InventorJohn D. Klarer
Life of this patent
Estimating the term…
Abstract
A vehicle wheel alignment sensor unit is configured with an absolute rotational position sensor to provide an absolute rotational position of a mounting shaft relative to the vehicle wheel alignment sensor unit enabling resumption of operation and recall of stored runout data subsequent to an operational disruption such as a system power loss. An internal power source maintains the integrity of the sensor memory for a definite span of time during momentary system power losses such as battery changes or during overnight shutdowns, permitting the mounting shaft runout compensation values to be maintained and utilized upon the restoration of system power.
Claims19
A method for re-establishing runout compensation of a vehicle wheel alignment sensor unit having a mounting shaft operatively coupled to a vehicle wheel, comprising the steps of:
- obtaining runout compensation data representative of runout present about a complete rotation of the mounting shaft relative to the vehicle wheel alignment sensor unit;
- associating said runout compensation data with at least one absolute rotational position of the mounting shaft relative to the wheel alignment sensor unit;
- storing said obtained runout compensation data and said associated absolute rotational position in a memory;
- identifying a current absolute rotational position of the mounting shaft relative to the vehicle wheel alignment sensor unit;
- and
- comparing said current absolute rotational position with said stored associated absolute rotational position to identify at least one runout compensation value associated with a current rotation position of the mounting shaft relative to the vehicle wheel alignment sensor unit.
An improved vehicle wheel alignment sensor unit including a housing, a mounting shaft having an axis about which the housing is rotatably disposed, at least one angle sensor, and a micro-processor operatively coupled to the at least one angle sensor, the improvement comprising:
- a magnet operatively coupled to the mounting shaft;
- a first Hall Effect sensor disposed in proximity to said magnet, said first Hall Effect sensor configured to generate a first signal representative of an rotational position of said magnet about the axis of the mounting shaft;
- a second Hall Effect sensor disposed in proximity to said magnet, said second Hall Effect sensor configured to generate a second signal representative of an rotational position of said magnet about the axis of the mounting shaft;
- wherein said micro-processor is operatively coupled to said first and second Hall Effect sensors to receive said signals to identify an absolute rotational position of said magnet about the axis of the mounting shaft from said received first and second signals;
- and
- wherein said micro-processor is configured to utilize said identified absolute rotational position to identify a runout compensation value associated with said current rotational position.
An improved vehicle wheel alignment sensor unit including a housing, a mounting shaft having an axis about which the housing is rotatably disposed, at least one angle sensor, and a micro-processor operatively coupled to the at least one angle sensor, the improvement comprising:
- a magnet operatively coupled to the mounting shaft;
- a two-axis Hall Effect sensor disposed in proximity to said magnet, said two-axis Hall Effect sensor configured to generate a signal representative of an absolute rotational position of said magnet about the axis of the mounting shaft;
- wherein said micro-processor is operatively coupled to said two-axis Hall Effect sensor to receive said signal;
- and
- wherein said micro-processor is configured to utilize said identified absolute rotational position, together with stored data representative of a sinusoidal runout pattern associated with an absolute rotational position of said magnet, to synchronize rotation of said mounting shaft about said axis with said sinusoidal runout pattern.
The improved vehicle wheel alignment sensor unit of claim 12 wherein said second Hall Effect sensor is a two-axis Hall Effect sensor.
The improved vehicle wheel alignment sensor unit of claim 12 wherein said at least one signal is representative of a coarse absolute rotational position measurement, and wherein said at least one second signal is representative of a fine absolute rotational position measurement.
An improved vehicle wheel alignment sensor unit including a housing, a mounting shaft having an axis about which the housing is rotatably disposed, at least one angle sensor, and a micro-processor operatively coupled to the at least one angle sensor, the improvement comprising:
- a magnet operatively coupled to the mounting shaft;
- a two-axis Hall Effect sensor disposed in proximity to said magnet, said two-axis Hall Effect sensor configured to generate a signal representative of an absolute rotational position of said magnet about the axis of the mounting shaft;
- wherein said micro-processor is operatively coupled to said two-axis Hall Effect sensor to receive said signal;
- and
- wherein said micro-processor is further configured to compare said identified absolute rotational position with at least one selected rotational position of the mounting shaft relative to the housing to identify when the sensor unit is rotationally disposed at said selected rotational position.
A method for facilitating mounting of a vehicle wheel alignment sensor unit relative to a mounting shaft on a no-compensation wheel adapter, comprising:
- identifying an absolute rotational position of the mounting shaft relative to the vehicle wheel alignment sensor unit;
- and
- comparing said identified absolute rotational position with at least one predetermined rotational position of the mounting shaft relative to the vehicle wheel alignment sensor unit to identify when the sensor unit is rotationally disposed at a selected rotational position.
Dependencies are inferred from the claim text.