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Re: 3-finger vs 5-finger designs - when does the extra finger actually pay off?

Posted: Sat Nov 22, 2025 5:49 pm
by mary.taylor6
Minor factual note: 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: 3-finger vs 5-finger designs - when does the extra finger actually pay off?

Posted: Thu Dec 04, 2025 3:48 am
by williams84
Agreed, and I'd add: Palm sensing gets less attention than fingertip sensing, but a lot of power grasps (holding a box, a tool handle) rely more on palm and lateral finger contact than fingertip contact, so under-sensing the palm can leave a real blind spot in grasp confidence. 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: 3-finger vs 5-finger designs - when does the extra finger actually pay off?

Posted: Sun Dec 07, 2025 2:31 pm
by matthew43
@williams84 This raises a question for me - 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. Kind of makes me think about how different this all looked even three years ago.

Re: 3-finger vs 5-finger designs - when does the extra finger actually pay off?

Posted: Mon Dec 08, 2025 1:56 am
by larrysokolov
@matthew43 Side note that might be relevant: 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: 3-finger vs 5-finger designs - when does the extra finger actually pay off?

Posted: Wed Dec 17, 2025 11:27 pm
by byang
Not sure I fully agree 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. 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. Reminds me a bit of the early drone hobbyist scene, honestly.