Pulsed robotic inspection

• US 4,838,696 A
• Filed: 09/24/1985
• Issued: 06/13/1989
• Est. Priority Date: 01/28/1983
• Status: Expired due to Term

• Current Assignee: LMI Technologies Inc.
• Original Assignee: Diffracto, Ltd. (LMI Technologies Inc.)
• Inventors: Pryor, Timothy R.
• Primary Examiner(s): Evans, F. L.
• Application Number:
  US06/779,457
• Time in Patent Office: 1,358 Days
• Field of Search: 356/372, 356/373, 356/375, 356/376, 356/383, 356/384, 356/385, 356/387, 901/2, 901/47, 33/125 A, 33/125 C, 250/237 G
• US Class Current: 356/602
• CPC Class Codes: G01B 11/02 for measuring length, width or thickness G01B11/08 takes precedence
• CPC Class Codes: G01D 5/36 Forming the light into pulses

Abstract

Robotic machines such as coordinate measuring machines, contour projectors and other optical measuring machines are provided wherein a pulsed light is used to "freeze" the dimensional or positional data. The light source of an electro-optical sensor which in motion on the machine during an inspection operation is pulsed responsive to a triggering pulse from an encoder. Where the motion is in more than a single axis, the triggering pulse can be provided from that encoder which experiences the most rapid motion or which is associated with the direction of the greatest dimension change of the part under inspection. Several different forms of position encoding apparatus are also disclosed.

Claims

1. A method for determining at least one dimension, location or other characteristic of a part being inspected utilizing an optical sensor attached to an inspection machined, said method comprising the steps of:

providing a read command signal to cause the optical sensor to begin sensing and, at essentially the same time, determining a first position of at least one axis of the inspection machine,

determining a second position of said at least one axis when the sensor, in sensing the part, has accumulated sufficient data from sensing the part to provide a useful reading,

determining, from the first and second positions of said at least one axis, data related to an intermediate position of said at least one axis between said first and second positions, and

determining from a combination of said intermediate location data and said sensor reading, the characteristic of the part.

2. A method according to claim 1 in which axes compensation sensors are used and the intermediate location of the axes compensation sensors is further determined.

3. A method according to claim 1 wherein said light sensor comprises a scanning photodetector array and said first and second axis positions are determined within a single photodetector array scan.

4. A method according to claim 1 wherein multiple positions of said axis, between said first and second positions, are sequentially stored in memory with respect to time and related to time based sensor data stored in a further memory during a scan of said sensor so as to more accurately determine the axis position at the time a feature of said part is sensed.