I’m wondering if it’s possible to use position inputs from two encoders to generate the error signal for a single motor (i.e. by addition/subtraction of two encoder inputs)
The reason for this is that I am designing a robot arm, and want to have encoders mounted directly to each joint axis (i.e. not directly to the motors), but two of my joints (J5 and J6) are coupled with a differential drive arrangement.
The result is that if you drive both motors with the same direction/speed, only J5 rotates, and if you drive the motors in opposite directions, only J6 rotates.
This produces the following relationship: (units are degrees)
J5/6 Motor A Error = (J5 Encoder Error + J6 Encoder Error)/2
J5/6 Motor B Error = (J5 Encoder Error - J6 Encoder Error)/2
Maybe the stock firmware isn’t capable of this, but I don’t mind modifying the firmware to enable this functionality. I am really just wondering if this is possible.