Calculating a Current Limit for a Climber Arm System

When doing empirical testing, keep in mind that the battery voltage changes as the match goes on. You might find that an acceptable current limit with a new battery won’t be enough power after running a hard match and having a lower voltage!

Personally, I’m a fan of current limits for some aspects of a robot, like an intake or a conveyor system. These types of systems rely on speed, where a high current condition indicates something very bad is happening. With a climber, you’re focused much less on speed and much more on torque. In this situation, you might expect a high current event. There can be a fine line between “enough current to do what’s needed” and “too much current”, and that line depends on the length of time you’re running at that current.

When it comes to climbers, I prefer to look at the movement rather than the current. In our case, we’re running our climber with Neo’s, and use the built-in encoder to see if the motor is stalled. If it’s stalled for too long, then the code stops it to prevent it from burning out. You can find our code here. If you struggle with finding an appropriate current limit, consider implementing a similar no-stall mode! It would help ensure the motor stops when it hits the bar, instead of over-driving and twisting the shaft.

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