The first thing my kids did last year after creating one of the “standard” builds (clawbot I believe?) was to burn out a motor. Looking at the Snapshot build, I expect the exact same thing would happen unless we add some protection features for the arm motor.
What are ways I can stop a motor from running if it’s overheating, especially in the scenario where it’s being told to move (by the student on the controls) but can’t move (because whatever is attached to the motor is physically blocked from moving further).
Apologies if this has been answered before; I’m new and couldn’t find anything by searching. I’m not entirely sure if I’m posting under the right topic, but I tried my best!
If you are talking about driving it too far into the mechanical limits of the motion, you can do that through software using the integrated encoders in the arm motor (same with the claw).
Hopefully someone already has an example of this software and can post.
Also consider trying out motor torque limits, especially for the extender arm. Most especially look at setting motor timeouts for any autonomous operation of the extender arm; this can shut off the motor automatically after a certain amount of time, so if it doesn’t reach the target position after a number of seconds, it stops movement.
Here is where I see frequent design mistakes that cause motors to overheat.
A best practice is to only allow the motor to run when it is being controlled by a button or stick. IE: It’s not good to continuously apply 50% power to the motors in the closing direction to hold on to something.
Next is to teach them about setting the Stop Mode on a motor to Hold when they want an arm or a claw to maintain position.
If a motor has to continue to fight to keep the position of an arm then teams will want to introduce counterweights (or rubber bands) to assist the motor.
I see overheating is when students are moving an arm without any gears to ratio the power. It would be the rare exception to connect an arm directly to the motor output. Use gears to slow down the movement and gain power.
It can be a problem is when the motors don’t have enough power. Teams may want use motors in parallel groups for running things like flywheels.
