Special issue on whole-body control of contacts and dynamics for humanoid robots
Auton Robot
Special issue on whole-body control of contacts and dynamics for humanoid robots
Serena Ivaldi 0 1 2 3 4
Jan Babicˇ 0 1 2 3 4
Michael Mistry 0 1 2 3 4
Robin Murphy 0 1 2 3 4
0 Robin Murphy
1 Michael Mistry
2 Texas A&M University, College Station , USA
3 University of Birmingham , Birmingham , UK
4 Jožef Stefan Institute , Ljubljana , Slovenia
Whether you are walking on a concrete floor, standing on a carpet, or sitting on a soft chair, your entire body continuously controls the posture and the contact forces that are produced by acting on rigid and compliant surfaces. Sometimes, like when reaching for a distant object or standing inside a moving bus that suddenly brakes, humans plan intentionally new contacts to preserve their balance and avoid falling. For humanoid robots to act in unstructured natural environments as humans do, contacts and physical interactions are necessary and unavoidable. In recent years, whole-body control techniques have matured to the point where various humanoid robots can robustly interact with their environment. Robots may exploit predictable contacts to aid in goal achievement, as well as learn dynamics of contact to generalize over novel tasks and domains. They may regulate their compliance to cope with unpredictable contacts and ensure safe behaviors. While these achievements are a major milestone for robotics, they still need to be applied to more challenging situations, inspired by natural settings and physical interaction scenarios. There is a strong need for advanced methods that can handle multiple contacts, unforeseen or
-
intentional, with different rigidity properties, and
guarantee the robust, autonomous execution of actions (balancing,
walking, manipulation) in variable contexts.
Such a need has never been as evident as was in the
DARPA Robotics Challenge (DRC), an international
competition funded by the US Defense Advanced Research Projects
Agency. During the DRC, several international teams were
remotely controlling a semi-autonomous humanoid robot to
perform whole-body tasks that involved contacts, such as
walking, driving a car and climbing stairs. The DRC spurred
the development of new humanoid robots and advances in
both mechanical design, hardware and software
development. Independently of the DRC, many projects addressing
control of contacts were funded by the European
Commission, such as CODYCO,1 COGIMON2 and WALKMAN.3
The latter was also instrumental to the design and building of
the homonym humanoid robot that participated to the DRC.
This increased interest for whole-body control has also
become apparent through the proliferation of several
international workshops at the most important robotics
conferences, such as the well attended workshop “Whole-body
Compliant Dynamical Contacts for Humanoid Robotics” at
ICRA 2013 in Karlsruhe, Germany.4 Several workshops
followed up, such as the “Torque-Controlled Humanoids” in
HUMANOIDS 20135 and the workshop “Towards a
Unifying Framework for Whole-body and Manipulation Control”
in RSS 2015.6
1 http://www.codyco.eu/.
2 http://cogimon.eu/.
3 http://www.walk-man.eu/.
4 http://www.codyco.eu/index.php/workshop-icra2013.
5 http://www.codyco.eu/index.php/workshop-humanoids2013.
6 http://www.codyco.eu/index.php/45-workshop-rss2015.
This special issue of the Autonomous Robots journal aims
at presenting the advances in whole-body control of real
robots, focusing on control and learning techniques applied to
estimation, control and adaptation of whole-body dynamics
movement and contact forces that go beyond basic balancing
abilities. The special issue received the support of the
IEEERAS Technical Committee in Whole-Body Control through
advertisement on its website.7 Papers were solicited with an
open call that was advertised about six months before the
deadline. A deadline extension was then allowed, as many
authors were still engaged in the DRC. We received more
than thirty submissions to the special issue, which were
rigorously reviewed by up to four reviewers, as well as by at
least one of the guest editors. Eight papers were selected
for this special issue. We consciously decided to narrow the
impressive pool of submissions to those papers which
presented relevant research and success stories with real robotics
platforms, shown in Fig. 1.
The paper “Optimization-based locomotion planning,
estimation and control design for the Atlas humanoid robot”
by Kuindersma et al., presents an overview of the
optimization algorithms for planning and control that were developed
for their Atlas robot competing in the DRC. Particularly, they
describe a sparse nonlinear trajectory optimization algorithm
that combines full body kinematics with centroidal
dynamics to efficiently compute whole-body motions in presence of
multiple contacts. Their controller relies on reduced
dynamical models to construct an efficiently-solvable quadratic
programming problem with active-sets, which is able to
achieve stable walking and (...truncated)