Two years ago at IROS 2015 in Germany, Honda R&D presented a paper on an experimental new humanoid robot designed for disaster response. This wasn’t entirely surprising, since we’d guessed that Honda had started working on a humanoid designed to be more robust, and practical, than Asimo after the Fukushima disaster. But as with most large Japanese companies, Honda does an excellent job of (almost) never communicating about the projects that it has under development. Pretty much the only sneak peeks we ever get come from research papers, and last week at IROS 2017 in Vancouver, we got the biggest look inside Honda’s humanoid robotics research and development program that we’ve had in years.
In a paper entitled “Development of Experimental Legged Robot for Inspection and Disaster Response in Plants,” roboticists from Honda R&D showed off the latest prototype of their disaster relief robot, the E2-DR. It’s strong, it’s nimble, and it can even get rained on without exploding.
According to Honda, “the following functional items should be achieved for inspection, maintenance and first response for disasters in social infrastructures, such as plants”:
- Three dimensional movement such as stairs, stepladders and vertical ladders with minimum size cages including transitions between ladders and steps
- Moving in narrow free widths and narrow spaces
- Moving over pipes on the floor
- Passing through closed doors along corridors
- Able to absorb contacts while moving
- Moving upon scattered debris
- Perception of environment for planning and monitoring
- Prevention of catastrophic fall when robot loses power while moving in a high place such as stairs and ladders
That’s a comprehensive list, and most of the robots that competed in the DARPA Robotics Challenge would find it hard to do most of those things. E2-DR is 1.68 meters high and weighs 85 kilograms, which includes a 1000-Wh lithion-ion battery good for a 90-minute operating time. At only 25 cm “thick,” it can squeeze through 30-cm gaps, a size which Honda designed towards because factories often have “shortcut” passages of about that width that can be used to get around blocked corridors. E2-DR has a total of 33 degrees of freedom, including 8 DoFs per arm, 6 DoFs per leg, 2 for its torso, and 1 for hands and head.
To climb stairs, E2-DR can rotate its torso 180 degrees, which has the effect of reversing the direction of its knees, so they don’t bump on the steps. You can see this in action 30 seconds into the video; it helps the robot especially with steep stairs. (This was the same approach adopted by DRC-HUBO, the robot that won the DARPA Robotics Challenge.)
To keep E2-DR’s size and mass to a minimum, Honda decided to trade out traditional communication cables for optical fibers, which are eight times smaller at just 0.5-mm in diameter. Optical fibers have a reputation for being less robust, but Honda says that they tested one by twisting and bending it one million times without having any problems. The hands are only designed for basic gripping to aid in mobility (like climbing ladders or stairs), as Honda has other plans for interacting with the world:
As for manipulation tasks, we assume that special tools with wireless communication designed for robots can be used. Therefore the proposed robot does not need to have dexterous hands but only needs to have the ability to grasp the tools and structures in environments such as a cross bar of a ladder to move.
On its head, E2-DR is sporting two rotating Hokuyo laser rangefinders, a monocular camera with a synchronized LED flash, a SR4000 time of flight camera, and a stereo camera coupled to an infrared light projector. There are also cameras and a 3D sensor on each of the hands. It sounds like the expectation is that the robot will be almost entirely teleoperated, although some DRC-style flexible autonomy seems like it’ll be in the works eventually, especially since Asimo has plenty of autonomy already.
The last piece of the puzzle here is making sure that E2-DR can handle real disasters, and that means making it dustproof, splashproof, and able to operate between -10 and 40 °C, all of which it can do. The robot’s joints use a labyrinth structure and grease to keep out contaminants, and Honda came up with a “segregated cooling structure” to move heat out of the E2-DR’s body. With an Intel Core-i7 CPU, a discrete GPU, and DC-DC converters that suck down 226 watts by themselves (not including the motor drivers), there’s a lot of heat to get rid of. Honda solved this by routing air ducts through E2-DR’s torso, with internal fans to keep the air moving. Heat producing hardware is attached to the outside of the ducts with thermal conducting sheets, and fins inside the ducts help to maximize cooling.
So far, Honda has gotten E2-DR to do the following:
(a) Bipedal walking at 4 km/h
(b) Quadrupedal walking at 2.3 km/h
(c) Stepping over a 200mm pipe
(d) Frontal transition between ladder and floor
(e) Sideways transition between ladder and floor
(f) Climbing up 200mm stairs
(g) Quadrupedal walking through an 800mm walkway
(h) Bipedal walking through a 500mm walkway
(i) Passing through an 800mm door
(j) walking on piled debris
(k) Walking under 26mm/hour rain for 20 minutes
(l) Climbing up and down a vertical ladder under 26mm/h rain
Notably missing here is any fall testing. Honda suggests that the robot can stand up on its own after falling down, although we don’t know any specifics about how structurally durable it is.
At their IROS talk, Honda stressed that E2-DR is just a prototype right now, and that there’s lots to be done before the robot can be useful. They’ve been working on it for several years, but the overall scale of the project is a “company secret.” At this point, Honda’s priority is teaching E2-DR to handle collisions, while also developing a system for “control of the robot for real usage.” We’re most excited about the latter, and maybe at IROS 2019 we’ll see E2-DR performing practical tasks. Or, you know, earlier would be cool too.