Paper Info
Title
Coupled Control Systems: Periodic Orbit Generation With Application to Quadrupedal Locomotion
Abstract
A robotic system can be viewed as a collection of lower-dimensional systems that are coupled via reaction forces (Lagrange multipliers) enforcing holonomic constraints. Inspired by this viewpoint, this letter presents a novel formulation for nonlinear control systems that are subject to coupling constraints via virtual “coupling” inputs that abstractly play the role of Lagrange multipliers. The main contribution of this letter is a process - mirroring solving for Lagrange multipliers in robotic systems - wherein we isolate subsystems free of coupling constraints that provably encode the full-order dynamics of the coupled control system from which it was derived. This dimension reduction is leveraged in the formulation of a nonlinear optimization problem for the isolated subsystem that yields periodic orbits for the full-order coupled system. We consider the application of these ideas to robotic systems, which can be decomposed into subsystems. Specifically, we view a quadruped as a coupled control system consisting of two bipedal robots, wherein applying the framework developed allows for gaits (periodic orbits) to be generated for the individual biped yielding a gait for the full-order quadrupedal dynamics. This is demonstrated on a quadrupedal robot through simulation and walking experiments on rough terrains.
Year
DOI
Venue
2021
10.1109/LCSYS.2020.3006963
IEEE Control Systems Letters
Keywords
DocType
Volume
Robotics,cooperative control,optimization
Journal
5
Issue
ISSN
Citations 
3
2475-1456
0
PageRank 
References 
Authors
0.34
0
3
Name
Order
Citations
PageRank
Wen-Loong Ma1256.05
Noel Csomay-Shanklin223.42
Aaron D. Ames31202136.68