Atlas (DARPA Robotics Challenge version)

What Atlas was

Atlas was a humanoid robot built for disaster response. DARPA commissioned it from Boston Dynamics of Waltham, Massachusetts, and the machine made its public debut on 11 July 2013 ^[1]. In its original form it was 6 ft 2 in tall and weighed 330 pounds ^[1] — roughly the build of a large adult, which matters for a machine intended to work in places built for people.

How the original machine was put together

The first Atlas had 28 hydraulically actuated joints ^[2]. Hydraulic actuation drives joints with pressurised fluid rather than electric motors, which gives high force for a given size at the cost of pumps, fluid lines and heat. Atlas accordingly carried a hydraulic pump and thermal management hardware on board ^[2]. Its sensor head came from Carnegie Robotics and included LIDAR and stereo sensors ^[2] — sensing used to build a picture of nearby surfaces and obstacles. An on-board real-time control computer handled the low-level running of the machine ^[2]. It came with two sets of hands, one provided by iRobot and one by Sandia National Labs ^[2], so teams could pick the end effector that suited their approach.

Tethered operation

In its first form Atlas was not a self-contained machine. A tether connected it to an off-board power supply and to a computer, and a human operator issued commands through that computer ^[1]. Power and command computing therefore sat outside the robot, and the tether constrained where and how it could move. Keeping power and computing off the machine is a common arrangement in early-stage robot platforms, because it reduces what the robot itself has to carry while the software and control side is still being worked out.

The DARPA Robotics Challenge

Atlas was the platform built for the DARPA Robotics Challenge. Seven Atlas robots were given to the teams that qualified from a simulation-based round of the challenge ^[1]. Those teams then used their Atlas robots at the live DRC Trials in December 2013 ^[1]. Handing the same machine to several groups means the comparison between teams rests on their software and control methods rather than on differences in hardware.

Changes for the 2015 finals

Ahead of the June 2015 DRC Finals in Pomona, California, DARPA asked Boston Dynamics to make three changes: switch Atlas to on-board power and wireless communication, strengthen its limbs, and improve its durability ^[1]. The work was completed in mid-2015 ^[1]. With power and communication moved onto the machine, the robot no longer depended on the tether for energy and commands. The stronger limbs and improved durability address a different problem: live trials put repeated physical strain on a 330-pound machine, and hardware has to survive that strain to be tested at all.

Place in the field, and retirement

The original Atlas was a hydraulically actuated robot ^[2], and the changes made for the finals kept that underlying design while removing its dependence on outside power and cabling. Later, Boston Dynamics announced the retirement of the hydraulic Atlas in April 2024 ^[3]. What ended was the hydraulic line of Atlas machines — the branch of the design that began with the tall, tethered platform unveiled in 2013.

Across its life the platform went through a clear sequence: a tethered research machine handed to qualifying teams ^[1], live use at the DRC Trials in December 2013 ^[1], a mid-2015 rebuild for on-board power, wireless communication, stronger limbs and better durability ^[1], and finally the retirement of the hydraulic version in April 2024 ^[3]. For readers looking back on humanoid robotics, Atlas is a useful marker of how a full-size hydraulic humanoid was actually fielded: built by a robot company for a government research programme, operated at first through a tether and an operator's commands ^[1], and only later made to carry its own power and communications ^[1].