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 Robotics engineers in Switzerland and Italy are developing
algorithms that they hope will make a dog robot robust enough for
use in search and rescue missions and environmental disasters that
are too dangerous to employ humans.
The HyQ quadruped robot was developed and built by Claudio Semini,
of the Italian Institute of Technology (IIT) in Genoa, who completed
it in 2010. A copy of the robot was built in 2012 for ETH Zurich
Professor Jonas Buchli's laboratory, part funded by the National
Science Foundation. Buchli's team is developing algorithms to
increase the robot's viability.
ETH Zurich postdoctoral researcher Thiago Boaventura told Reuters
that HyQ's actuation system makes it mechanically robust and allows
it to run at speed. "One of the key characteristics of this robot is
that we use an actuation system that is mechanically very robust and
is strong and fast, so wheels, hydraulic activators, to drive the
joints. Us humans have muscles to move the joints, we use this kind
of actuations to drive and move the joints and these actuators are
able to withstand impact that some kind of actuations, for example
electro motors they might have some issues. This is a key
characteristic of this robot here to perform and withstand impacts
that are intrinsic to walking and trotting motions, for example,"
said Boaventura.
 Pointing to one of the actuators, he said that they were "able to
control all the interaction forces that we generate with the leg. So
we can essentially set the dynamical behavior of the robot using the
software, so we can define the stiffness and damping parameters of
the leg and all the joints using only software instead of real
springs or dampers that are placed on the robot."
Emulating the elastic elements and springiness of the robot's joints
by using software, rather than hardware, is another positive.
Boaventura said an actuator in each knee joint allows programmers to
control the force applied when overcoming a variety of terrain.
"Here in the knee joint we have the hydraulic actuator that's
attached to the joint through a load cell. This load cell is what
allows us to control the force that we apply in this joint and
consequently to the terrain, so the joints control the forces that
will move the robot," he said.
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Buchli agreed that HyQ's force control is crucial. "The force, or
what we also call torque control, of this robot is a very important
feature when you're interacting with the environment and it actually
is the only way to really make interaction with the environment
robust, and that's our research interest in this machine, that we
have a machine that can go out there and work in environments that
are not known to the robot and do these robustly, so that eventually
we can use these robots to do something useful," he said.
According to Buchli, HyQ shares many similarities with Spot, the dog
robot developed by Google's Boston Dynamics, not least its ability
to withstand being kicked and pulled around when on the move. Yet he
says the multinational company's secrecy makes it difficult to
understand the specifics of Spot's functionality. Conversely the
makers of HyQ have revealed many of the secrets behind their robot,
encouraging others in the academic community to emulate their work.
In tests on a treadmill and outside of the laboratory, researchers
at IIT, where Buchli and Boaventura previously worked, have shown
for the first time that an actively controlled machine, without
passive springs, can successfully walk, run and jump over obstacles
and difficult terrain.
Buchli's team at ETH Zurich is using HyQ as a research platform on
so-called Optimal and Learning Control, with the aim of making it
undertake useful, dynamic, tasks.
The eventual aim is for HyQ, or a future successor, to be able to be
sent to conduct dirty and dangerous tasks, such as at a nuclear
disaster site, instead of humans.
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