WO1995015479B1

WO1995015479B1 - Vehicle alignment system

Info

Publication number: WO1995015479B1
Application number: PCT/US1994/012824
Authority: WO
Filing date: 1994-12-01
Publication date: 1995-07-06

Abstract

An improved vehicle alignment system (1) includes automatic angle and distance range calibration whereby various vehicle distances such as track width and wheelbase may be measured electro-optically during the alignment process. The system also includes an improved process which results in shorter measurement cycles for the sensors by utilizing an electronic shutter control. The sensors (19, 21 and 23) work in pairs, and a novel synchronization scheme is used to ensure that the emitters (25) of one sensor (19) are not radiating at the same time the emitters (25) of the other sensor (21) of that pair are radiating and to determine which emitter (25) of the pair corresponding to a sensor (19) is radiating. Reflections of the emitters (25) from nearby surfaces are discriminated from direct transmissions so that the angle of incidence is accurately determined. Moreover, determination of the angle of incidence is simplified by use of a lens (95) whose image position varies in a specific manner as the imaged object moves radially away from the axis of the lens (95). The present system is particularly suited for measuring difficult alignment measurements such as toe-out on turns electro-optically with a minimal number of sensors (19, 21, 23).

Claims

AMENDED CLAIMS

[received by the International Bureau on 12 June 1995 (12.06.95); original claims 5 and 6 amended; remaining claims unchanged (2 pages)]

with respect to another wheel of the vehicle and the distance measured corresponds to track width.

4. A vehicle wheel aligner comprising: a radiation source adapted to be removably mounted to a first wheel of a vehicle; an image detector adapted to be removably mounted to a second wheel of a vehicle, said image detector having a plurality of pixels for receiving radiation from the radiation source and generating a pixel-by-pixel representation of the image falling on the detector; a mask including an aperture disposed adjacent the image detector for defining an image of the radiation source on the image detector; a lens disposed between the aperture and the image detector, the lens having a focal length and ray turning angle which is dependent on the position and angle of the incident radiation on the lens surface, said lens in combination with said aperture performing an inverse tangent function on the incident radiation; a controller operatively connected to the image detector for determining angles of incidence of radiation from the radiation source from the pixel-by- pixel representation of the image falling on the detector and determining vehicle alignment information therefrom.

5. A method of electronically determining distance in connection with the servicing of a vehicle comprising: removably mounting a sensor to a front wheel of a vehicle; removably mounting a pair of radiation sources to a rear wheel of the vehicle; projecting a pair of images from the pair of radiation sources upon an image detector associated with said sensor, said images being separated such that the separation is a function of the distance between the pair of sensors; and electronically determining the separation of the images and calculating therefrom the distance between said image detector and the pair of radiation sources and electronically determining the toe of said front wheel of a vehicle from the representation of the images falling on the image detector at a first steered angle of said front wheel.

6. The method as set forth in claim 5 further including the steps of storing the toe and distance information corresponding to said first steered angle, moving said front wheel to a second steered angle, acquiring toe and distance information corresponding to the second steered angle, and determining the change in the steered angle from the toe and distance information at both steered angles. 7. A method of electronically determining distance between a pair of sensors mounted in known relationships to a vehicle comprising: mounting a first sensor at a first position on one side of a vehicle; mounting a second sensor at a second position on the opposite side of the vehicle from the first sensor; projecting a pair of images upon an image detector associated with one of said sensors, said images being separated such that the separation is a function of the distance between the pair of sensors; and electronically determining the separation of the images and calculating therefrom said distance between said pair of sensors. 8. A method of electronically determining distance between a pair of sensors mounted in known relationships to a vehicle comprising: mounting a first sensor at a first position on a vehicle other than on a wheel of the vehicle; mounting a second sensor at a second position on the vehicle; projecting a pair of images upon an image detector associated with one of said sensors, said images being separated such that the separation is a function of the distance between the pair of sensors; and electronically determining the separation of the images and calculating therefrom said distance between said pair of sensors. 9. A method of correcting vehicle wheel alignment angles comprising: