I have a wheel that I need to be able to drive by either the motor, or by manually turning it. I’m using the Motor 269 with the Cortex and programming in ROBOTC. Is there really no way to float the motor or set it to neutral? The page for the Motor Controller 29 says that “brake mode” might not be supported by my compiler, but it seems to me that the motor is always braked; I can’t get it to not brake.
Without neutral, the only solutions I can think of are either gearing up far enough for the motor to be manually back-drivable, or implementing some sort of reverse PID to move the motor slightly if there is the encoder detects a slight turn. Both solutions have their problems.
Also, neutral mode would be hugely useful for manually adjusting arm or motor position; I’d be really disappointed if there’s no way to do this.
A few quick thoughts… All the vex motors have a friction drag torque of about 6 to 10% of the max torque. A 393 has about 1 inlb and as I recall, the 269 is about half that. So even if a wire is disconnected, a manual twist will have to provide at least that torque. If the manual twist is slow enough then the back emf braking will be small. If you have to manually turn at a fast rate then you might consider adding a simple switch that opens the motor leads during manual operation or just provide a slip clutch coupling to the motor that can easily be overridden by manual torque.
These suggestions may or may not be helpful with your particular requirements. Let us know more about your design if you need additional help.