ICRA'20 Presentation LQR-Assisted Whole-Body Control of a Wheeled Bipedal Robot with Kinematic Loops

This video presents "LQR-Assisted Whole-Body Control of a Wheeled Bipedal Robot with Kinematic Loops" published in the IEEE Robotics and Automation Letters (RA-L) and presented at the virtual 2020 IEEE International Conference on Robotics and Automation (ICRA), Paris, France.
Abstract - We present a hierarchical whole-body controller leveraging the full rigid body dynamics of the wheeled bipedal robot Ascento. We derive closed-form expressions for the dynamics of its kinematic loops in a way that readily generalizes to more complex systems. The rolling constraint is incorporated using a compact analytic solution based on rotation matrices. The non-minimum phase balancing dynamics are accounted for by including a linear-quadratic regulator as a motion task. Robustness when driving curves is increased by regulating the lean angle as a function of the zero-moment point. The proposed controller is computationally lightweight and significantly extends the rough-terrain capabilities and robustness of the system, as we demonstrate in several experiments.
paper: www.ascento.ethz.ch/wp-conten...
paper video: • LQR-Assisted Whole-Bod...
project website: www.ascento.ethz.ch
DOI: 10.1109/LRA.2020.2979625
Chapters:
0:00 Introduction
0:30 Motivation
1:37 Modeling
3:07 Control
5:35 Balancing Robustness Experiment
5:59 Adaptive Legs Experiment
6:19 Curve Leaning Experiment
6:50 Indoor Parkour
7:12 Disturbance Rejection
7:35 Terrain Driving
7:46 More Info

[@expented]

seems to me inspired by the 80s "Mouser" invented by Dr. Baxter Stockman, haha! :) great job Alessandro

[@archi2nd]

Love that little bot

[@zeev]

7:48 makes me want to roller blade on one foot while skate-boarding .

[@MAtifAli]

that's very interesting work. Do you have a paper that shows detailed kinematics modelling?

[@julast6658]

I would be interested in it for wheel chairs -

[@ServetEdu]

any plans to open-source your work, including mechanical drawings, electrical diagrams and software?

[@davidmalawey]

Does Ascento have awareness of it's leg deflection? If so, to what resolution?

[@AscentoRobotics]

Yes! The joint encoders in the hip motors measure their rotation with a precision of ‹0.025° (17-bit encoders). This allows Ascento to directly calculate the extension of the corresponding leg linkage and thereof also the relative wheel positions.

[@legosam2067]

He deserves to be in Star Wars

[@Clever_Motel]

Already has the shape and function of a BD unit.

[@crafter2u]

nice just needs hands now

[@samhamsord7942]

I see one HUGE flow. You are doing great job at preventing it to ever tip over. But it will happen anyway sometimes. Wouldn't it be cool to have some additional system to put it back on wheels from whatever position?

[@victorklemm]

It's actually already able to do that! But that's not topic of this paper. Please have a look at our previous video: ua-cam.com/video/e1ZBNFv8kh0/v-deo.html

[@herp_derpingson]

I dont like these QA style conference videos. Sounds unnatural.

[@DP-sq7lw]

Yeah, it sounds like two robots talking to each other.