Robotic 3D pick & place assembly of dishwasher insulation material

Need

The insulation pad is flexible and porous; in the stack every pad sits shifted and skewed relative to the one below, and its top surface is wavy. A fixed pick point grips the pad in the wrong place; the pad sags in transfer and lands on the tub out of tolerance.

Solution approach

A 3D laser profile sensor on a post scans the top of the stack and builds a point cloud of the top pad; centre, angle and stack height are computed from it and sent to the robot. The robot turns the vacuum gripper to that angle, picks the pad and sets it on the tub; a ring-lit camera measures the pad edges against the tub edges, and if the offset is large the robot corrects the pad and re-checks.

Process steps

1. 01

   3D scan

   The laser line sweeps the top of the stack and builds a point cloud of the top pad.

2. 02

   Pose

   Centre, angle and height of the pad are computed from the cloud and sent to the robot.

3. 03

   Pick

   The robot turns the gripper to the measured angle and picks the pad by vacuum.

4. 04

   Place

   The angle is corrected on the way and the pad is set down on top of the tub.

5. 05

   Verify

   The robot clears the view and a camera measures the pad edges against the tub edges. If there is an offset the robot corrects the pad and the measurement is repeated.