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Re: How much does hand mass distribution affect arm control complexity?
Posted: Sun Aug 30, 2026 11:59 am
by dchen
I'd take that specific number with a grain of salt, honestly.
Object occlusion by the robot's own hand during the final approach to a grasp is a common and annoying perception problem - the closer the hand gets to a good grasp position, the more it blocks the camera's view of exactly what it's about to grab.
Re: How much does hand mass distribution affect arm control complexity?
Posted: Sun Aug 30, 2026 11:59 am
by sven.wilson4
@dchen This is a great summary, thanks.
Object occlusion by the robot's own hand during the final approach to a grasp is a common and annoying perception problem - the closer the hand gets to a good grasp position, the more it blocks the camera's view of exactly what it's about to grab.
Re: How much does hand mass distribution affect arm control complexity?
Posted: Sun Aug 30, 2026 11:59 am
by emily45
@sven.wilson4 Slight correction, though the overall point stands:
Grasp planning for deformable or non-rigid objects (bags, cables, cloth) remains one of the genuinely unsolved problems in manipulation - rigid-body grasp models simply don't capture how the object will behave once contact starts.
Re: How much does hand mass distribution affect arm control complexity?
Posted: Sun Aug 30, 2026 11:59 am
by camila.jackson0
@emily45 Agreed, and I'd add:
Figure's fourth-generation Dexterous Hand (on Figure 02/03) reportedly offers 16 degrees of freedom per hand with sensors integrated into each finger, aimed at fine force control tasks like handling small electronic components without crushing them. Payload-to-hand-weight ratio varies a lot across current dexterous hands, and it's a meaningful tradeoff - more DoF and finer sensing generally means more actuators and mass in the hand itself, which eats into the arm's usable payload budget.
Re: How much does hand mass distribution affect arm control complexity?
Posted: Sun Aug 30, 2026 11:59 am
by mia_lars
@camila.jackson0 Short answer:
Vision-based grasp confidence estimation (predicting success before attempting a grasp) and tactile-based confirmation (confirming after contact) are complementary rather than competing - vision helps you choose a grasp, tactile tells you if it actually worked.
Re: How much does hand mass distribution affect arm control complexity?
Posted: Sun Aug 30, 2026 11:59 am
by karen_kim
@mia_lars Small correction on one detail:
Compliant wrists that absorb impact during a bad approach or misjudged contact reduce mechanical stress on the whole arm, which matters a lot for long-term reliability even though it's a less visible feature than the hand itself. Vision-based grasp confidence estimation (predicting success before attempting a grasp) and tactile-based confirmation (confirming after contact) are complementary rather than competing - vision helps you choose a grasp, tactile tells you if it actually worked.
This whole thread is a good reminder how young this field still is.
Re: How much does hand mass distribution affect arm control complexity?
Posted: Sun Aug 30, 2026 11:59 am
by shill
@karen_kim Here's the relevant bit as far as I understand it:
Vision-based grasp confidence estimation (predicting success before attempting a grasp) and tactile-based confirmation (confirming after contact) are complementary rather than competing - vision helps you choose a grasp, tactile tells you if it actually worked. In-hand reorientation (repositioning a grasped object without setting it down) is one of the more advanced manipulation skills, requiring either a highly dexterous hand with enough DoF or clever use of gravity and controlled slipping - it's an active research area rather than a solved problem.
Re: How much does hand mass distribution affect arm control complexity?
Posted: Sun Aug 30, 2026 11:59 am
by betty.king
Counterpoint:
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.
Re: How much does hand mass distribution affect arm control complexity?
Posted: Sun Aug 30, 2026 11:59 am
by dchen
@betty.king Worth being a little skeptical of the marketing angle here.
Cable routing through a wrist joint with multiple degrees of freedom is a genuinely tricky mechanical design problem - tendons and wiring both need enough slack to avoid binding through the full range of motion without tangling or fraying over thousands of cycles.
Re: How much does hand mass distribution affect arm control complexity?
Posted: Sun Aug 30, 2026 11:59 am
by kwilliams
I can speak to this a bit.
Grasp planning for deformable or non-rigid objects (bags, cables, cloth) remains one of the genuinely unsolved problems in manipulation - rigid-body grasp models simply don't capture how the object will behave once contact starts.