One-armed HyQ robot can knock obstacles out of its way
One-armed HyQ robot can knock obstacles out of its way
Reuters By Matthew Stock
6 hours ago
Quadruped robots could soon be an important tool for
replacing humans in dangerous situations. The maneuverability of advanced
four-legged robots means they can navigate uneven terrain and could aid rescue
efforts and disaster recovery scenarios.
No matter how agile a legged robot is, however, their
role has traditionally been limited to load carrying or observation tasks.
A team of robotics engineers from the Italian Institute
of Technology (IIT) in Genoa have designed a robotic arm that they've attached
to one of their flagship HyQ quadruped robots in order to give it manipulation
capabilities.
According to Claudio Semini, head of the Dynamic Legged
Systems (DLS) lab, future quadruped robots operating in real-world applications
will most likely need a degree of manual dexterity.
"For us, it was natural to start to design also an
arm, and then the plan is to build two arms and have them both on the robot to
create a 'centaur' style of robot. And with the two arms the robot can be
deployed to the real area where it needs to do any maintenance work or turn a
valve in a rescue scenario or pick up a sample in a contaminated area or just
clean up radioactive materials; there's a lot of potential future applications
where manipulation is really important," Semini told Reuters.
Eventually, their centaur-style robot will consist of a
quadruped locomotion platform and a pair of arms. Currently, the team is
testing one prototype arm attached to the front of the four-legged robot. To
demonstrate how the HyQ-Centaur could operate, an obstacle is placed in its
path with the robot arm being remotely controlled to knock it out of the way.
The hydraulically actuated arm was designed by PhD
student Bilal Ur Rehman who explained that the arm not only adds dexterity to
the robot but can aid its maneuverability.
"Right now this arm can carry 10 kg when it's fully
extended. It's total weight is 12.5 kg, so it can almost carry the same
external load as its own weight. It's also pretty fast with the hydraulics
speeds. You can use it as a counter force if you apply an external force on the
body of the robot. You can use the arm as a tail as well to counter the
external forces," said Rehman.
The additional weight of the arm and the forces exerted
by its motion gave the roboticists an added hurdle to overcome. They developed
algorithms that 'train' the robot to ignore the external disturbances and
remain stable.
"If we have a moving mass in front, that creates
also a disturbance in the legs. So what we're developing is algorithms that can
take into account that external disturbance from the payload or from the arm.
And then servo the legs, control the legs in a way to compensate for these disturbances.
And we've managed to do this very well; there's an example where we moved the
arm left and right relatively fast, and if we don't use the smart controller
the robot moves a lot. But if we turn on the smart controller, the torque and
forces in the cylinders and joints are optimized so that the robot is
relatively firm and rejects all these external disturbances," said Semini.
The HyQ robot was first presented as part of Semini's PhD
thesis in 2010. It shares similarities with quadruped robots developed by other
institutions, such as Spot the dog robot developed by Google's Boston Dynamics.
But Semini said that while seeing a robot running and balancing in a mainly
reactive way looks impressive, the real test comes when such a robot has to
cross very rough terrain where a carefully planned foot placement is vital.
Much of their research is focused on developing algorithms that help HyQ decode
its surroundings and plan the next footsteps, said Semini.
"Compared to other teams in China and the U.S. we have
focused a lot on the versatility. So this (HyQ) platform can do many different
motions ranging from very fast motions like a run or a jump. But it can also do
the more careful navigation on rough terrain where we need to plan really one
foothold after the next. And this is important, once we see the 3D map of the
environment we can start to understand how to best move through that
environment," he said.
"We don't want to be the fastest or the best
climber, but we want to have a machine that can do many of these motions; as in
the real world, the machine will need to have many different skills."
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