Motor protection function

[asmidgard]

I have seen descriptions of motor rated current and maximum current, but I'm still wondering, won't the motor's metal wires burn out if a current exceeding the rating flows for a certain period of time? I can't find information about features like electronic thermal functions or I2T, so I'm left with this question. I assume this is taken into consideration, so please tell me about it.

[otegami]

Thanks for the thoughtful question!

I checked the DM-J4310/J4340/ 8009 docs we have and couldn’t find any explicit mention of electronic-thermal/I²t style protection.
What I do see are threshold-based protections that disable “Enable” when tripped.

ref: https://docs.openarm.dev/hardware/specifications/motor

Could this be helpful? We do get T_MOS, T_Rotor, ERR, and position/velocity/torque from the feedback frame,
which might be enough for host-side thermal/protection logic.

cc: @pruthakj / @Hardware-Hero If you have any insights on the hardware/design side, it’d be great if you could share them and help out.

[asmidgard]

Thank you for your response. It seems the information isn't readily available.

Regardless of whether it's an open-source robot or not, I believe users need to know what safety features are, and are not, included. This is because users must be able to set boundaries for how to use the product and conduct their own risk assessments.

To encourage future users to purchase with confidence, I would appreciate a response.

We also shouldn't guess safety features from their names. While we can infer the motor control method to some extent from FB values, motor protection is a very difficult function to understand from the outside.

Unfortunately, you'll only realize that the protection feature wasn't effective after you've burned out the motor, but by then, the only option is to replace the motor with burned wires.

[Hardware-Hero]

Sorry for the late reply.
I completely agree with your thoughts on the hardware in open source projects and the safety features that users should be informed about.

I will be contacting the manufacturer directly to find out more information that is not included in the specifications. I plan to share the results of my inquiry with the community this week.