Autonomous Motion Conference Paper 2007

Inverse dynamics control with floating base and constraints

In this paper, we address the issues of compliant control of a robot under contact constraints with a goal of using joint space based pattern generators as movement primitives, as often considered in the studies of legged locomotion and biological motor control. For this purpose, we explore inverse dynamics control of constrained dynamical systems. When the system is overconstrained, it is not straightforward to formulate an inverse dynamics control law since the problem becomes an ill-posed one, where infinitely many combinations of joint torques are possible to achieve the desired joint accelerations. The goal of this paper is to develop a general and computationally efficient inverse dynamics algorithm for a robot with a free floating base and constraints. We suggest an approximate way of computing inverse dynamics algorithm by treating constraint forces computed with a Lagrange multiplier method as simply external forces based on FeatherstoneÕs floating base formulation of inverse dynamics. We present how all the necessary quantities to compute our controller can be efficiently extracted from FeatherstoneÕs spatial notation of robot dynamics. We evaluate the effectiveness of the suggested approach on a simulated biped robot model.

Author(s): Nakanishi, J. and Mistry, M. and Schaal, S.
Book Title: International Conference on Robotics and Automation (ICRA2007)
Pages: 1942-1947
Year: 2007
Bibtex Type: Conference Paper (inproceedings)
Address: Rome, Italy, April 10-14
URL: http://www-clmc.usc.edu/publications/N/nakanishi-ICRA2007.pdf
Cross Ref: p2597
Electronic Archiving: grant_archive
Note: clmc

BibTex

@inproceedings{Nakanishi_ICRA_2007,
  title = {Inverse dynamics control with floating base and constraints},
  booktitle = {International Conference on Robotics and Automation (ICRA2007)},
  abstract = {In this paper, we address the issues of compliant
  control of a robot under contact constraints with a goal of using
  joint space based pattern generators as movement primitives,
  as often considered in the studies of legged locomotion and
  biological motor control. For this purpose, we explore inverse
  dynamics control of constrained dynamical systems. When the
  system is overconstrained, it is not straightforward to formulate
  an inverse dynamics control law since the problem becomes
  an ill-posed one, where infinitely many combinations of joint
  torques are possible to achieve the desired joint accelerations.
  The goal of this paper is to develop a general and computationally
  efficient inverse dynamics algorithm for a robot
  with a free floating base and constraints. We suggest an
  approximate way of computing inverse dynamics algorithm by
  treating constraint forces computed with a Lagrange multiplier
  method as simply external forces based on FeatherstoneÕs
  floating base formulation of inverse dynamics. We present how
  all the necessary quantities to compute our controller can be
  efficiently extracted from FeatherstoneÕs spatial notation of
  robot dynamics. We evaluate the effectiveness of the suggested
  approach on a simulated biped robot model.},
  pages = {1942-1947},
  address = {Rome, Italy, April 10-14},
  year = {2007},
  note = {clmc},
  slug = {nakanishi_icra_2007},
  author = {Nakanishi, J. and Mistry, M. and Schaal, S.},
  crossref = {p2597},
  url = {http://www-clmc.usc.edu/publications/N/nakanishi-ICRA2007.pdf}
}