Wheels Or Legs? Why Not Both?

Out of the thousands of constraints and design decisions to consider when building a robot, the way it moves is perhaps one of the most fundamental. The method of movement constrains the design and use case for the robot perhaps more than any other parameter. A team of researchers at Texas A&M led by [Kiju Lee] is trying to have their cake and eat it too by building a robot with wheels that transform into legs, known as a-WaLTR (Adaptable Wheel-and-Leg Transformable Robot).

a-WaLTR was designed to conquer one of wheeled robots’ biggest obstacles: stairs. By adding a bit of smarts to determine whether a given terrain is better handled by wheels or legs, a-WaLTR can convert its segmented wheels into simple legs. Rather than implemented complex and error-prone articulated legs, the team stuck with robust appendages that remind us a little of whegs.

The team will show off their prototype at DARPA OFFSET Sprint-5 in February 2021, which is a program focused on building robots that can form adaptive human-swarm teams.

Thanks to the rise of 3D printers and hobbyist electronics there are more open-source experimental robot designs than ever. We’ve seen smaller versions of the famous Boston Dynamics’ Spot as well as simpler quadruped bots with more servos. a-WaLTR isn’t the first transforming robot we’ve seen, but we’re looking forward to seeing more unique takes on robotic locomotion in the future.

Thanks to [Qes] for sending this one in!

28 thoughts on “Wheels Or Legs? Why Not Both?

      1. Hmm, that’s not exactly what I remember. I think the one I’m thinking of was a “Stomper” with special wheels that did something similar (and on all 4 wheels, according to my memory). That “animal” truck seems a lot newer than what I remember, though similar in function.

        Of course, my memory is definitely NOT a reliable source!

          1. Yes, that’s the one I was thinking of!
            I was mistaken in thinking it was a Stomper. Thanks for finding that. 😀
            I looked up Stompers because I remember when they first came out. Okay, I’m old. That was in 1980, and I got one for Christmas that year.

  1. Am I missing something? I don’t see any legs. I just see wheels that transform from smoothly round to claw-like. That doesn’t mean it’s not a useful and effective idea. But to me, a leg is something that works by articulation rather than rotation, and this doesn’t fit the bill at all.

    1. I must agree, a wheel is still a wheel even if it’s in a different shape than the norm.

      That being said, kudos to the people that worked on this clever project. As someone that often has to rely on a mobility scooter to get around, I appreciate that there are people working on ways to to make wheels go up stairs.

      1. I’d be very scared of using these on a mobility scooter. One suspects the centre of gravity of a mobility scooter might be a bit higher than this robot? The thought of a mobility scooter falling over backwards down the stairs is bad enough, let alone with someone in it.

        1. For such a scooter you’d mount the chair portion on a platform that can tilt fore and after. Then have it self level as the stairs are climbed.

          The OP is pretty clever but my first thought would be to look at memorizing the “climbing” hand trucks that use a tri-wheel setup as shown here…


    1. There is ‘nothing’ new under the sun …. But is neat to see someone bringing it to life again. We need reminded sometimes ;) . And who knows, some brainiac might come up with a breakthrough to make it useful for every day use.

  2. Looks like they’d work for ‘paddles’ to if you run into some water. Zip across the pond…. Definitely would have to figure out ‘dirt/Mud’ problem to prevent jamming….. Neat concept though.

  3. Those are NOT legs! Legs means feet, ankle, knee, hip, thig. Where the hell are them? that is just a “triangular whells”!
    Why H-a-D allows this? It is only to get some click? are you short of worthy columnists? Where is the problem? maybe you does not pay enough…. Quality means cost, and here I don’t see qulity.

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