Testing and Cause of Failure for Encoders and Hall Effect sensors

[Mike Betts]

Originally Posted by ChrisH

There are other ways that might be cheaper and lighter than a full up scope. And these might be?

Chris,

I would suggest this.

On another note, I feel that the single most important function which the mechanical team can provide the electrical team is to integrate the sensor(s) and wiring into your design from the beginning. In other words, protect it so that it will not break...

Walk around any competition and you will see wonderfully designed mechanical mechanisms with limit switches or potentiometers mounted with rubber bands, tie wraps and hot glue. These devices and their wires are invariably exposed to the interface between 130 lb robots colliding at 5 to 10 ft/sec.

Just as invariably, you will hear the mechanical team complaining about the lack of robustness of the sensors. In my view, it is the shortsightedness of the mechanical team which allowed such a fragile item to be exposed to such an environment.

Don't leave the mechanical design of electrical components to the electrical team. They do not have your experience.

As an example: When you CAD a gearbox, add in an extra gear and mount for an encoder within the gearbox at design time. Without side loads and properly protected, these devices should be as robust as anything else in your geartrain.

Designing for failure tends to encourage failure. Worrying about failure analysis during the competition can become a self fulfilling prophesy. Break your pots in the fall and learn how to keep them from breaking.

Driver practice, software verification and strategy aside, the winning robot is not the fastest, the most powerful or the most clever design. At the end of the day, it is often the last robot standing which wins the competition.

JMHO,

Mike