Humanoid-universe.com

<t>Slight correction, though the overall point stands:

Off-the-shelf RC servos are a reasonable starting point for a first small biped because they bundle motor, gearbox, and basic position control in one part, but they generally can't deliver the torque density or backdrivability needed to scale ...

<t>Follow-up question though -

A realistic hobbyist bill-of-materials for a small biped balloons fast once you add a real IMU, decent motor controllers, a reasonable battery/BMS setup, and enough compute for onboard control - the headline '$5k' budget assumes a fair amount of DIY fabrication ...

<t>@carol38 One nitpick -

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. Field-oriented control (FOC) tuning directly affects how smooth torque ...

<t>Slight correction, though the overall point stands:

Reflected inertia is what a limb 'feels like' to the outside world through the gearbox - a high-ratio harmonic drive reflects a lot of the rotor's inertia back to the joint, making the limb feel stiffer and less forgiving on unexpected ...

<t>@william.moreau6 One nitpick -

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. Harmonic drives use high ...

<t>@william.moreau6 I dealt with almost this exact situation.

IMU drift over time (bias instability) is usually the real culprit behind slowly diverging state estimates, not noise - it's typically handled with sensor fusion against other references (visual odometry, joint kinematics) rather than ...

<t>Pretty much this. One thing to add:

Vibration is one of the most underrated sources of noisy IMU and tactile readings - mounting matters as much as sensor quality, and a poorly isolated mount can add more noise than the sensor's own datasheet specs would suggest. LiDAR gives reliable, lighting ...

@james15 Just to be precise about one thing: Wet, oily, or otherwise low-friction objects are still a genuine edge case for most current hands, since tactile sensing and grasp-force controllers are typically tuned and validated on dry, higher-friction test objects.

<t>Small correction on one detail:

Thermal margin in a densely packed humanoid chassis is often the real limiting factor on sustained performance, not raw motor power - actuators get thermally throttled well before they'd hit their absolute torque limits, especially during repeated high-load ...

From hands-on experience, Fast charging accelerates capacity fade over repeated cycles, so fleet operators generally have to choose between minimizing downtime (fast charging) and maximizing pack lifespan (slower charging or swap-based approaches) rather than getting both for free.