TY  - BOOK
AB  - Legged robots have many potential applications
in real-world scenarios where the tasks are too dangerous for
humans, and compliance is needed to protect the system against
external disturbances and impacts. In this paper, we propose a
model-based controller for hierarchical tasks of legged systems
subject to external disturbance. The control framework is
based on projected inverse dynamics controller, such that the
control law is decomposed into two orthogonal subspaces,
i.e., the constrained and the unconstrained subspaces. The
unconstrained component controls multiple desired tasks with
impedance responses. The constrained space controller maintains
the contact subject to unknown external disturbances,
without the use of any force/torque sensing at the contact
points. By explicitly modelling the external force, our controller
is robust to external disturbances and errors arising from
incorrect dynamic model information. The main contributions
of this paper include (1) incorporating an impedance controller
to control external disturbances and allow impedance shaping
to adjust the behaviour of the motion under external disturbances,
(2) optimising contact forces within the constrained
subspace that also takes into account the external disturbances
without using force/torque sensors at the contact locations. The
techniques are evaluated on the ANYmal quadruped platform
under a variety of scenarios.
DA  - 2018
LA  - eng
PY  - 2018
TI  - A Model-based Hierarchical Controller for Legged Systems subject to External Disturbances
UR  - https://nbn-resolving.org/urn:nbn:de:0070-pub-29189237
Y2  - 2024-11-25T04:05:17
ER  -