Equal Motor Output with Encoders Help

[Gunnar Frahm]

Answers to your questions.
1) We used a handheld digital tachometer to measure each motors RPM individually at free speed. The RPM hovered in those ranges for each motor.
2) The shaft is in fact twisting a bit. We are worried that the couplings are going to break as a result of this.
4) The arm we are moving is a "boom-like" structure 48.5 inches long and made out of aluminum. The fulcrum where the motors (connected by the shaft) are an inch from the end. Just moving the arm is heavy enough, but it is more so when there is a load on the end of it. This is a video of our robot when we were using a snowblower motor to pivot the arm. The snowblower motor ended up not giving as much lift power as we wanted. https://www.youtube.com/watch?v=YJ1LrNceyyI
5) We were not using PID at all. Just normal select triangles for buttons to create an output.