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Re: Anyone using capacitive proximity sensing for pre-contact grasp adjustment?
Posted: Fri Sep 20, 2024 9:43 am
by deborahperez
Thanks for laying this out, genuinely useful.
Unitree's Dex3-1 dexterous hand packs around 33 pressure/tactile sensors per hand across the fingers and palm, capable of sensing pressure roughly in the 10g-2500g range - a useful reference point for what 'production tactile sensing' looks like right now. Depth sensing range and reliability both degrade outdoors in direct sunlight for most structured-light and active stereo cameras, since the ambient IR washes out the projected pattern - it's a real limitation for humanoids intended for anything beyond indoor, controlled environments.
Re: Anyone using capacitive proximity sensing for pre-contact grasp adjustment?
Posted: Sat Sep 21, 2024 2:01 am
by dubois35
@deborahperez This raises a question for me -
Latency between a perceived event (like a slip) and a corrective control response matters enormously for balance - even 50-100ms of extra perception latency can be the difference between a smooth recovery and a fall, which is part of why a lot of balance-critical sensing is proprioceptive rather than vision-based.
Re: Anyone using capacitive proximity sensing for pre-contact grasp adjustment?
Posted: Sat Sep 21, 2024 3:55 am
by deborahperez
@dubois35 That's the official framing, at least - reality tends to lag a bit.
Depth sensing range and reliability both degrade outdoors in direct sunlight for most structured-light and active stereo cameras, since the ambient IR washes out the projected pattern - it's a real limitation for humanoids intended for anything beyond indoor, controlled environments.
Re: Anyone using capacitive proximity sensing for pre-contact grasp adjustment?
Posted: Tue Sep 24, 2024 3:58 pm
by kwilliams
@deborahperez Slight correction, though the overall point stands:
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.
Re: Anyone using capacitive proximity sensing for pre-contact grasp adjustment?
Posted: Wed Sep 25, 2024 9:23 am
by deborahperez
+1 to this. Worth adding:
Estimating joint torque from motor current draw is cheap and requires no extra sensor, but it's less accurate than a dedicated torque sensor because it doesn't capture friction losses through the gearbox - good enough for coarse control, not always for precise force-controlled tasks.
Re: Anyone using capacitive proximity sensing for pre-contact grasp adjustment?
Posted: Tue Oct 01, 2024 2:31 am
by williams84
From hands-on experience,
SLAM in a working warehouse is harder than in a controlled lab mainly because the map keeps changing - pallets move, people walk through, lighting shifts near dock doors - so a lot of production systems lean on semi-static maps refreshed periodically rather than pure continuous SLAM.