Day 67

The chain conversion on the second stage of the arm finally got all the way put together. It was slow going because we had to resolve some clearance issues that were missed in CAD. Now there is a new problem with the gear box, it flexes a lot when powering the arm down. Watch the Neos closely you can see the flex.

CAD has already released a fix which adds two plates, a bearing to support the output shaft and extends the output shaft. With only two shafts and three plates to make we should have the upgrade ready to put on the robot by Saturday.

We noticed the flex when we were tuning PID on the arm. It was happening while the arm was very poorly tuned. The flex might not be as bad if the arm is well tuned but we want to solve this problem now at our shop rather then during competition.

Now that the arm has a chain(and isn’t controlled by a winch) we can calculate static gains to use with feed forward control. Programming got this added to the arm, feed forward makes the PID easier to tune which results in a smoother moving arm. Next up we have to tune PID on the second joint and because the arm got .5″ longer we have to find all the new key positions of the arm.






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