“Robots are typically heavy and hard — they aren’t very agile and they can be dangerous when near humans because they aren’t very flexible,” Alex Nemiroski, a former Harvard postdoctoral fellow who worked on the project, told Digital Trends. “In our work, we took inspiration from spiders, and used soft materials — plastic drinking straws and rubber — to design a new type of robotic actuator that is loosely based on the form of a spider’s joints and exoskeleton.”
Drinking straws share more in common with insects than you might initially think — thanks to a shared high strength-to-weight ratio. Spider joints were especially interesting to the researchers because, unlike most other creatures, they extend their limbs hydraulically by filling their joints with fluid.
“We did a very similar thing, but pneumatically, with air,” Nemiroski continued. “This principle is very simple to implement, doesn’t require hard electronic actuators, and ensures that the joints remain flexible and soft. By cutting notches into the straws and inserting small balloons, we could extend each joint by inflating the balloon, and retract it by deflating the balloon. We were able to build progressively more complex ‘arthrobots’ by adding more legs and more joints to each leg until we managed to create a full eight-legged spider.”
A paper describing the work was recently published in the journal Soft Robotics. While it’s still a long way from commercialization, Nemiroski said that there are possible real-world applications for the research.
“This work shows that very simple materials, with minor modifications, can be assembled to perform complex motions, and use nothing but air to move,” he said. “In the future, using tougher materials for both the exoskeleton and the inflatable joints will enable these robots to carry much more weight, including, potentially, people or supplies. These robots could be used in the future to navigate complex obstacles, such as rubble, in search and rescue operations, or to carry resources in the field.”
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