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GUIDE · 4 MIN READ

Humanoid manipulation

How to read the hand, gripper and payload figures humanoid makers publish, and what they mean when you choose a robot for manipulation work.

REVIEWED BY WBH · · DRAFTED WITH AI ASSISTANCE FROM THE CITED SOURCES

For: People who build, program or evaluate humanoid robots.

Hands, grippers and swappable tools

NEURA Robotics delivers 4NE1 Gen 3.5 with integrated high-dexterity hands and states that specialised or third-party end effectors are not part of the delivery [2]. Its product page also lists exchangeable forearms [1].

Agility Robotics went the other way for Digit: a modular system in which the robot snaps a different gripper onto its arms for each kind of work [12]. Agility's argument is durability: in its view a robot balancing on two legs will eventually fall, and delicate fingers break when it does [13]. Boston Dynamics says that for Atlas it has been iterating on gripper design to get the right mix of strength, fine motor skill and durability [21].

The AGIBOT Genie G1 lists a 6-DoF end effector that can be replaced with a two-finger gripper [8]. The AGIBOT X2 Ultra Edition supports optional OmniPicker and OmniHand modules [10]. For the Booster T2, the end effector is listed as optional, compatible with dexterous hands and grippers [20]. When you read such a listing, find out which end effector the quoted configuration actually includes.

Degrees of freedom in arms and hands

The Astribot S1 [15], AGIBOT's Genie G2 [9] and the A2-W [6] each list 7 degrees of freedom per arm. The count is not the same across a maker's range, and within one model the variant matters. The AGIBOT A2 Ultra has 7 joints per arm and a 6-DoF dexterous hand, while the A2 Lite has 5 per arm and no hand listed [4].

The hands change the total count for a robot. For the Booster T1, the standard arms have 4 degrees of freedom and are described as extensible [17]; with grippers the robot has 31 degrees of freedom in total (7 per arm, 1 per hand), and with dexterous hands 41 (6 per hand) [16].

NEURA's smaller 4NE1 Mini makes the same point from the buyer's side: the Pro version has 12 DoF dexterous hands, while the Standard version has no manipulation at all [3]. Before comparing two robots, check that the figures belong to the configuration you would actually buy.

Reading payload figures

Before comparing numbers, establish what each one describes:

  • Per arm or both arms: Astribot S1 gives 5 kg per arm at horizontal reach [15], while Booster T2 gives a maximum of 10kg for both arms together [18].
  • A best posture or the whole workspace: for the AGIBOT X2, the maximum of 3 kg holds in a specific posture, and across the full workspace the figure is ≤ 1 kg [11]. Booster adds that its arm payload varies significantly with posture [19].
  • With or without the end effector: AGIBOT states both X2 figures as without an end-effector [11], so ask whether a number includes the hand or gripper.
  • Brief or sustained: Boston Dynamics lists 50 kg instant and 30 kg sustained capacity for Atlas [22].
  • Repeated lifting: Agility says Digit 5 can repeatedly lift loads of up to 22.7 kg [14].

The AGIBOT A2 page lists a Max Arm Load of about 2 kg without saying whether that is per arm [5]. AGIBOT's A2-W page lists a single arm load of 5kg [6], and the Genie G2 documentation says each arm supports a payload of 5 kg [9]. NEURA states a payload of 10-100 kg for 4NE1 without saying on that page how it is measured [1], so treat such a range as a question to ask rather than a figure to compare.

Force and torque sensing

AGIBOT Genie G2 is equipped with a joint torque sensor in each joint, and its documentation says the robot can perform force-controlled operations including hole searching, insertion and surface alignment [9]. Other AGIBOT pages list force sensors. The A2-W carries 2 six-dimensional force sensors alongside its LiDAR and vision sensors [7], and the Genie G1 lists a six-axis force sensor [8].

On the G2, the joint sensors measure the torque applied to each joint, and its changes, in real time [9]. Where a maker lists only a force sensor, ask where it is mounted and what it measures.

Questions to ask before choosing

  1. Which end effector is included, and which are extra? NEURA, for example, excludes specialised and third-party tools from the 4NE1 delivery [2].
  2. Is the hand part of the variant you are pricing? The A2 Lite lists no hand [4], and the 4NE1 Mini Standard has no manipulation [3].
  3. Is the payload per arm or for both arms, and in which posture [19]?
  4. Does the figure include the end effector [11]?
  5. Is it an instant or a sustained value [22]?
  6. Does the task need force control, and is it measured at the joints or at the wrist [9]?

Where a page leaves a question open, as NEURA's does for its 10-100 kg payload range [1], put the question to the maker.