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Mobile manipulators

A wheeled or tracked base and a robot arm sold as one product — a robot that can go somewhere and then do something with its hands.

  • mobile manipulator
  • MoMa
  • arm on wheels

What it is

A mobile manipulator pairs a mobile base with one or more arms, so it can both move through a space and act on things in it. That is what a fixed arm and a plain mobile robot each lack: the arm cannot go anywhere, the base cannot pick anything up. The cost is complexity: base and arm must run as one machine, the whole is heavier and dearer than either half, and a tall arm is top-heavy.

Also called a MoMa or an arm on wheels. In this taxonomy it is a top-level branch, and the rule is commercial as much as mechanical: base and arm must be sold together as one product. A wheeled robot with a human-like torso is a humanoid instead.

What they are used for

  • Logistics — unloading trucks; Boston Dynamics' Stretch is a base, a long arm and a vacuum gripper built for that job.
  • Home and care research — Hello Robot's Stretch 3, a slim base with a telescoping arm, is the standard platform.
  • Consumer — the first mass-market example is a robot vacuum with a fold-away arm, the Roborock Saros Z70, which picks up socks.
  • Hobby and open-source research — the LeKiwi kit and XLeRobot put SO-ARM101 arms on a cheap base.

What to compare

Attribute Why it matters In this catalogue
payload What the arm can lift, usually far less than what the base can carry 2 kg (Hello Robot Stretch 3) – 23 kg (Boston Dynamics Stretch)
reach Floor to shelf in a home; trailer floor to top row in logistics 400 mm (WowRobo XLeRobot) – 1950 mm (Boston Dynamics Stretch)
arm_count One arm picks; two arms can hold and work 1 (Boston Dynamics Stretch) – 2 (WowRobo XLeRobot)
axes Fewer joints is fine for pick-and-place; more for reaching round things 5 (Hello Robot Stretch 3) – 6 (WowRobo XLeRobot)
battery_runtime Base and arm share one battery, so runtime is shorter than the base alone 120 min (Hello Robot Stretch 3) – 960 min (Boston Dynamics Stretch)
navigation The arm is useless if the base cannot find the shelf none (2), slam (1)
sdk ROS 2 and a Python API decide whether a lab can use it python (3), ros2 (1), proprietary (1)
mass Research platforms are built light enough for one person to carry upstairs 24.5 kg (Hello Robot Stretch 3) – 1300 kg (Boston Dynamics Stretch)

Price picture (observed 2026-10-28)

  • Research: USD 179 (Seeed Studio LeKiwi Kit (12V Version)) to USD 24,950 (Hello Robot Stretch 3).
  • Education, hobby & consumer: USD 2,000 (Roborock Saros Z70).
  • On quotation: Boston Dynamics Stretch.

Prices are the latest observation per product, in the seller's currency; see each record's offers for history and VAT notes.

In the catalogue

Professional / industrial: Boston Dynamics Stretch
Research: Hello Robot Stretch 3 · Seeed Studio LeKiwi Kit (12V Version) · WowRobo XLeRobot
Education, hobby & consumer: Roborock Saros Z70

Edge cases

  • Base and arm sold separately (a research UGV with a cobot on top): two entries linked by compatible_with.
  • Quadruped with an arm: still a quadruped; the arm is has_arm.
  • Wheeled humanoid with arms: a humanoid.
  • Kit that builds one fixed design (LeKiwi): classified as what it becomes, so here.

Related

Robot · Arm · Humanoid · Legged robot · Ground robot · Aerial robot · Aquatic robot · Wearable robot · Stationary robot · Kit · Wheeled robot · Wheeled-base humanoid

Rule of membership

Base and arm(s) sold together as one product. A base and an arm sold separately are two entries linked by compatible_with.

Category rb-5 in the whatrobot taxonomy.