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Re: Tactile fingertip resolution - how fine do we actually need it?

Posted: Thu Sep 04, 2025 10:07 pm
by olga_lind
@ethan17 Side note that might be relevant: Force/torque sensors near the ankle give a direct read on ground reaction forces, which is valuable for balance control, but they add cost, a failure point, and routing complexity right at a joint that already takes the most mechanical abuse.

Re: Tactile fingertip resolution - how fine do we actually need it?

Posted: Fri Sep 05, 2025 9:53 pm
by camila.jackson0
@olga_lind Can I ask a dumb follow-up - Event cameras (which report per-pixel brightness changes rather than full frames) are still more of a research curiosity than a production sensor for humanoids, mainly because the software ecosystem and processing pipelines around them are far less mature than for standard frame-based cameras.

Re: Tactile fingertip resolution - how fine do we actually need it?

Posted: Wed Sep 17, 2025 9:22 pm
by carol.robinson
I can speak to this a bit. Proprioception (the robot's sense of its own joint angles, velocities, and forces) tends to get less attention than flashy vision systems, even though a lot of balance and manipulation failures trace back to proprioceptive noise or miscalibration rather than a vision problem.

Re: Tactile fingertip resolution - how fine do we actually need it?

Posted: Thu Sep 18, 2025 4:56 pm
by johnrossi
I dealt with almost this exact situation. 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. Sensor fusion mostly earns its keep by covering for each individual sensor's weaknesses - vision struggles with occlusion and lighting, IMUs drift, force/torque sensors are noisy at low loads - fusing them gives a more robust estimate than any one source alone, independent of raw compute.

Re: Tactile fingertip resolution - how fine do we actually need it?

Posted: Fri Sep 19, 2025 10:32 pm
by dchen
@johnrossi I'll believe the stronger version of that claim when it's independently verified. 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: Tactile fingertip resolution - how fine do we actually need it?

Posted: Tue Sep 30, 2025 8:02 am
by mia_lars
Genuinely curious - 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. Reminds me a bit of the early drone hobbyist scene, honestly.

Re: Tactile fingertip resolution - how fine do we actually need it?

Posted: Wed Oct 08, 2025 8:17 pm
by lbianchi
Minor factual note: 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 trying to eliminate drift at the source.

Re: Tactile fingertip resolution - how fine do we actually need it?

Posted: Fri Oct 17, 2025 4:41 pm
by dubois35
@lbianchi Worth being a little skeptical of the marketing angle here. Tactile skin arrays have improved a lot, but 'good enough to matter' really depends on the task - coarse contact detection across a large area is fairly mature, while fine, high-resolution force distribution sensing (like a human fingertip) is still the harder problem. 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: Tactile fingertip resolution - how fine do we actually need it?

Posted: Fri Oct 17, 2025 11:53 pm
by cynthia.muller
@dubois35 To answer this directly: Proprioception (the robot's sense of its own joint angles, velocities, and forces) tends to get less attention than flashy vision systems, even though a lot of balance and manipulation failures trace back to proprioceptive noise or miscalibration rather than a vision problem. 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: Tactile fingertip resolution - how fine do we actually need it?

Posted: Fri Oct 24, 2025 2:29 pm
by williams84
Small correction on one detail: Sensor fusion mostly earns its keep by covering for each individual sensor's weaknesses - vision struggles with occlusion and lighting, IMUs drift, force/torque sensors are noisy at low loads - fusing them gives a more robust estimate than any one source alone, independent of raw compute. Makes me wonder how this looks in another five years.