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Re: How much does wrist DoF count actually matter for real tasks?
Posted: Sun Apr 06, 2025 3:06 pm
by kwilliams
@pierregreen I see it a little differently.
Imitation learning from human demonstration video (without robot teleoperation data) is an appealing way to scale up training data cheaply, but it runs into the embodiment gap - human hand kinematics and force profiles don't map directly onto a robot hand's very different mechanism. A lot of the manipulation shown in production demos still leans heavily on teleoperation, particularly for anything involving fine force control or novel objects - autonomous grasp success rates on genuinely unstructured, previously-unseen clutter are still well below what teleoperation can achieve.
Re: How much does wrist DoF count actually matter for real tasks?
Posted: Tue Apr 08, 2025 10:18 am
by park44
@kwilliams Related question -
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. Imitation learning from human demonstration video (without robot teleoperation data) is an appealing way to scale up training data cheaply, but it runs into the embodiment gap - human hand kinematics and force profiles don't map directly onto a robot hand's very different mechanism.
Re: How much does wrist DoF count actually matter for real tasks?
Posted: Wed Apr 09, 2025 4:59 am
by kwilliams
I see it a little differently.
Tendon-driven fingers let you move the heavier actuators back into the palm or forearm, keeping the fingers themselves light and fast, but they introduce cable routing, tensioning, and long-term wear problems that direct-actuated fingers don't have. 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 wrist DoF count actually matter for real tasks?
Posted: Fri Apr 11, 2025 11:10 am
by chenperez
Speaking from personal experience here,
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.
Re: How much does wrist DoF count actually matter for real tasks?
Posted: Sun Apr 13, 2025 8:04 pm
by park44
@chenperez Agreed, and I'd add:
A lot of the manipulation shown in production demos still leans heavily on teleoperation, particularly for anything involving fine force control or novel objects - autonomous grasp success rates on genuinely unstructured, previously-unseen clutter are still well below what teleoperation can achieve. Bimanual manipulation - two arms coordinating on one task - is harder than it looks mostly because of the added degrees of freedom and the timing/force coordination required; a lot of 'two-handed' demos are actually closer to two independent single-hand tasks done in sequence.
Re: How much does wrist DoF count actually matter for real tasks?
Posted: Tue Apr 22, 2025 7:04 pm
by zoeanderson
@park44 Genuinely curious -
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.
Makes me wonder how this looks in another five years.
Re: How much does wrist DoF count actually matter for real tasks?
Posted: Sun Apr 27, 2025 9:34 am
by yuki71
Genuine beginner question -
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: How much does wrist DoF count actually matter for real tasks?
Posted: Mon Apr 28, 2025 12:12 pm
by emilyperez
Worth being a little skeptical of the marketing angle here.
A lot of the manipulation shown in production demos still leans heavily on teleoperation, particularly for anything involving fine force control or novel objects - autonomous grasp success rates on genuinely unstructured, previously-unseen clutter are still well below what teleoperation can achieve.
Re: How much does wrist DoF count actually matter for real tasks?
Posted: Sat May 03, 2025 4:37 pm
by park44
@emilyperez I'd frame this differently.
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. 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 wrist DoF count actually matter for real tasks?
Posted: Mon May 05, 2025 4:57 am
by nicole57
@park44 Can I ask a dumb follow-up -
Tendon-driven fingers let you move the heavier actuators back into the palm or forearm, keeping the fingers themselves light and fast, but they introduce cable routing, tensioning, and long-term wear problems that direct-actuated fingers don't have.