What's underrated: motor design or gearbox design, for overall performance?

[dchen]

@freya.smith Tangent, but worth mentioning: Backdrivability is the property that lets an external force move a joint without destroying the gearbox or the motor - it's central to both safe human-robot contact and to letting a leg comply naturally when the robot stumbles.

[freya.smith]

This is a great summary, thanks. Torque sensing is frequently integrated directly into the actuator housing via strain gauges near the output flange or spring element, rather than bolted on as an external sensor, to save weight and reduce noise from mechanical slop. Reminds me a bit of the early drone hobbyist scene, honestly.

[rtorres]

@freya.smith Short answer: Backdrivability is the property that lets an external force move a joint without destroying the gearbox or the motor - it's central to both safe human-robot contact and to letting a leg comply naturally when the robot stumbles. Totally unrelated but has anyone else noticed how fast component costs are dropping this year.

[rivera14]

@rtorres I'd push back on this a bit. For dynamic walking and recovery, joint control bandwidth in the tens of Hz range is typically necessary to react to a stumble before the center of mass gets too far outside the support polygon. Backdrivability is the property that lets an external force move a joint without destroying the gearbox or the motor - it's central to both safe human-robot contact and to letting a leg comply naturally when the robot stumbles.