RetiredSucceeded by LittleDog United StatesAssisted

BigDog

A petrol-powered four-legged robot mule funded by DARPA to carry soldiers' gear over rough ground. Famous for recovering its balance when kicked or on ice.

Price: —DARPA-funded research robot, not sold
Height: 76 cmTaller than 82%
Weight: 110 kgHeavier than 98%
Payload: 150 kgCarries more than 96%
Speed: 6.4 km/hFaster than 24%
Battery: —Not published

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Why it matters

The first widely seen dynamically balanced quadruped robot built for a military load-carrying role.

Real-world use

Field trials only; the programme was discontinued at the end of 2013.

Timeline

First shown: 2005
Released: Not yet

Publicly described in February 2005

Maker

Boston DynamicsCompany · founded 1992 · Waltham, Massachusetts, United States

Owned by Hyundai Motor Group since June 2021 (80% stake bought from SoftBank for about $880M; SoftBank kept about 20%).

How it stacks up

Against other robot dogs that publish the figure. Pick a measure.

BigDog is taller than 82% of the 22 other robot dogs that publish a height. Bars show the 7 closest in date.

Height 76 cm 11 cm100 cm #5 of 23 · taller than 82%

Not published by the maker: joints, battery, price.

Public attention

A historic robot: no longer sold or in use, so it is not ranked against current machines.

6,820 views of its Wikipedia article in the last 90 days (BigDog)
No recent press stories listed yet

Measures how much people read and write about a robot, not how good it is. Measured 2026-10-13; same method for every robot. How it is measured

What’s inside

The parts the company has talked about publicly.

Movement: Walks on legs
How it runs: Assisted. An operator commanded its speed, direction and gait through a control unit, while onboard algorithms coordinated its posture and walking on uneven terrain.
Actuators & motors: 16 hydraulic actuators (four per leg), each with cylinder, servo valve, position and force sensors; pump driven by a 15 hp single-cylinder two-stroke engine (about 9,000 rpm).
Sensors & vision: About 50 sensors: joint position and force, ground contact, laser gyroscope, stereo vision, LIDAR, hydraulic pressure and temperature.
Compute: Ruggedised PC/104 stack: Pentium M running QNX for sensing and control, plus a Core Duo for vision.
Battery & power: Petrol engine (no battery power for locomotion); noise was the main reason it was shelved.
AI & software: QNX real-time OS with custom C++ control; dynamic balance.
Other details: About 110 kg, 0.76 m tall; carried up to 150 kg and climbed 35-degree slopes; a 2013 version added an arm that threw objects.

Lineage

Every Boston Dynamics (with Foster-Miller, NASA JPL and Harvard; DARPA-funded) machine in order.

Boston Dynamics also makes 5 humanoids. See every Boston Dynamics robot

Made, sold and where

Unit counts are usually company figures; analysts often disagree.

Price: Not publishedDARPA-funded research robot, not sold
How to get one: No official buying page found
Built: Several versions
Sold or delivered: not sold
Where it is sold or used: Boston Dynamics, Waltham, Massachusetts (with Foster-Miller, NASA JPL and Harvard)
Customers and pilots: DARPA-funded; programme ended in December 2013

Sources

Figures come from press coverage. Every link below backs something on this page.

Boston Dynamics / IFAC BigDog, the Rough-Terrain Quadruped Robot Boston Dynamics Boston Dynamics History & Legacy — Handle Wikipedia BigDog researchgate.net BigDog: how it is operated

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