Vision-guided precision robotic assembly of TV panels

Need

The clearance between the cell and its seat in the chassis is tight; robot repeatability alone is not enough, and the cell sits slightly differently in the gripper at every pick. The glass edge has low contrast; unless both corners are seen at the same time an angular error goes unnoticed.

Solution approach

Two long-focal-length cameras with ring lights look squarely at diagonal corners and see cell and chassis corner in the same frame; X, Y and angle offsets are computed from the two corners. If the first measurement is out of tolerance the offset is sent to the robot and the measurement is repeated; once within tolerance the cell is lowered and the corners are verified once more after release.

Process steps

1. 01

   Pre-position

   The chassis stops in the station and the robot brings the cell above it.

2. 02

   Acquire

   Two cameras image diagonally opposite corners of cell and chassis at the same time; the first offset is out of tolerance.

3. 03

   Correct

   The computed X, Y and angle offsets are sent to the robot and the measurement is repeated.

4. 04

   Set down

   Once the offsets are within tolerance the cell is lowered into the seat.

5. 05

   Verify

   After release the corners are measured once more.