Dual encoders

[seg9585]

Originally Posted by Caleb Sykes

My team is running a tank drive setup this year, and have added an encoder onto each side. We are also using the NavX for angle measurements. We will have a variety of methods that rely on angle measurements from the NavX and distance measurements using one or both encoders.

However, I am wondering if there is really any benefit to having both encoders. If for distance we just take a raw average of both measurements, we are basically getting slightly more precision in exchange for a doubled failure rate. It seems to me that unless you are using two encoders to sense angles in place of a gyro (or some sort of fusion) there is almost no benefit to having dual encoders.

How does your team integrate dual encoders into the code? Does anyone just mount/use a single encoder?

In industry, we would actually use 3 encoders and then always select the midvalue one.

Just as we say:
- With 1 sensor, you don't know that you're wrong.
- With 2 sensors, you know you're wrong but aren't sure which is correct.
- With 3 sensors, you always know which one is wrong and which is right

(From a single-fault-tolerance perspective)