Analysing hazardous environments
Sometimes an extreme situation requires a tool that can go to extremes. Emergency response teams often need to enter dangerous or confined spaces, but performing a search and rescue operation in precarious areas involves a high degree of risk.
Unstable structures, like collapsed buildings, are difficult for conventional robots and even drones to navigate. We’re working on robots that can pick their way through even the most unstable terrain to get the job done.
Nature has many examples of creatures that can move on uneven surfaces, with our team of scientists and engineers taking inspiration from the way they get around. Our multi-legged robots can go where other robots or human can’t, like a collapsed mine.
They can safely explore and assess confined and hazardous areas to perform reconnaissance, identify degrees of structural damage, and execute maintenance.
The evolution of hexapods
Our hexapods use biomimicry to replicate the movement of insects with the same number and configuration of legs, like ants and cockroaches. They are programmed with different gaits that have made their natural counterparts successful.
One of our hexapods, Weaver, has five joints on each of its six legs, enabling it to move freely and negotiate uneven terrain easily.It also has 'eyes' in the form of a pair of stereo cameras, allowing it to create a digital elevation map of an area, and detect any physical obstacles in its path. Sensors in each of its leg joints allow this insect-like bot to measure the forces felt at its foot tips. When each foot touches the ground, it feeds this information back through a sequence of algorithms.
By combining that input with its elevation map, Weaver can gauge the stability of the surface and adjust the stiffness of its legs as it travels. This allows it to avoid getting stuck or losing balance by adjusting the flexibility of its leg joints depending on the roughness of the terrain.
Then there's Gizmo, a small, streamlined hexapod designed for versatility and compact spaces. Gizmo is ideal for tasks like inspecting and mapping ceiling and floor cavities, a joboften needed in the construction and mining, where some areas are too difficult or unsafe for humans to reach.
While Gizmo’s servo motors are compact, they’re strong enough to carry a payload of up to 2kg in hard-to-access areas. The robot's small form, easy-to-control interface and the fact that it runs off a Raspberry Pi computer - a computer running on the easy-to-learn script Python - makes it an ideal platform for robotics education as well.
Gizmo is well-suited to exploring new worlds, too, and is currently featured as part of the Australian Space Agency’s Mars exhibition.
Bruce, on the other hand, can support 5kgs while still being able to operate effectively in a mix of flat and rough terrains. With 80 per cent of its structure 3D printed, Bruce combines fast dynamic locomotion on flat terrain and fast stable locomotion on rough terrain. This makes the Bruce ideal for applications in where it’s necessary to get there fast and stay stable on all kinds of surfaces.
Hexapod robots are ideal for working at 'dog scale' and 'catscale'. Dog size is perfect for forest systems, such as in bushfire management. They are more stable on littered forest floors than quadruped robots, and don’t damage the ground like track systems. Cat size can move stably through confined spaces.
Probing before stepping
One of hexapods' strong points is the ability to work on surfaces that might be prone to collapsing. These can be difficult to identify using 'exteroceptive sensing' (a robot's version of sight) alone. Environments like a leaf-covered forest floor, or snow/ice, can disguise holes that can disable most robots. Low light, smoke, or dust could make matters worse.
Biomimicry can also compensate in these conditions. When visibility is poor, animals often use senses such as touch to perceive the environment. In much the same way, multi-legged robots like Gizmo can probe the terrain using sensors in their legs to predictions about its safety before fully committing to stepping on it. This can be built into their regular gait.
Weaver can not only identify obstacles, but push them aside using one of its front legs. It estimates the weight first, to avoid overloading its leg joints by pushing something too heavy.
Future iterations of Weaver are planned to be able to use two legs, moving in different directions, to enable it to clear larger and more cumbersome objects out of its path.
Some jobs need six legs to get them done right
Robots like Weaver, Gizmo and Bruce are being deployed in a variety of emergency situations and helping to enhance range of processes within the construction and mining industries.
In the last six years, our research teams have designed a suite of legged robots for a range of applications, from emergency rescue operations to rainforest monitoring and aeroplane manufacturing, such as when inspecting the wing cavity of an aircraft.
We have also designed and implemented the world's first testbed for evolving legged robot controllers in hardware, capable of perpetual operation with inbuilt error reporting, data logging, experiment scheduling and behaviour monitoring.
Curious? Learn more about hexapods at CSIRO's Data61 Legged Robots.