We have two large FANUC Robots that depalletize full layers of liquid in trays of cans or cases of bottles using a global vacuum head. Generally works great.
But it sometimes happens that the edges of the large end-of-arm-tool head come into contact with misplaced product as the robot is moving downwards to pick the next layer. We have found that the in-built collision detection works best when the collision is near the center of the head, where the force is felt directly by the robot arm moving down. But when it is the edge that collides with product, the Robot keeps going down because of the way the forces act on the frame. This can damage and bend certain components.
So we'd like to supplement the software collision detection with some simple but robust sensors that could be added to the piece of aluminum that makes contact with the product in these events. We'd program the motion to stop as soon as any of them are activated.
My question is... do you have any suggestions for types / models of sensors that would be well-suited for this application? We would want something that detects a physical touch, not a capacitive sensor that detects the near-presence of an object, because it often happens that the product is very close to the edge and we don't want false positives - we just want to detect these collisions earlier than with the software collision detection.
Thanks in advance, gents.