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: https://www.ascento.ethz.ch/wp-conten...
paper video:    • LQR-Assisted Whole-Body Control of a ...  
project website: https://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