Jumping Jollbot

A robot that jumps like a grasshopper and rolls like a ball has been developed by a Bath University researcher.

A robot that jumps like a grasshopper and rolls like a ball has been developed by a Bath University PhD researcher.

The Jollbot can jump over obstacles and roll over terrain, meaning it could be used for space exploration or land survey work.

One of the major challenges that faces robots designed for space exploration is being able to move over rough terrain. Robots with legs are generally very complex, expensive to build and control, and encounter problems if they fall over. Wheels are a simpler solution to this, but are limited by the size of obstacles they can overcome.

To solve the problem, Rhodri Armour and his colleagues at Bath University’s Centre for Biomimetic and Natural Technologies have been looking to nature for inspiration – designing a robot that jumps obstacles in its path like an insect.

The Jollbot is shaped like a spherical cage and can roll in any direction, giving it the manoeuvrability of wheels without the problem of overturning or getting stuck in potholes.

The robot is also flexible and small, weighing less than a kilogram, meaning it’s not damaged when landing after jumping and is therefore less expensive than conventional exploration robots.

‘In the past, others have made robots that jump and robots that roll; but we’ve made the first robot that can do both,’ said Armour.

In nature, there are two main types of jumping: hopping, like a kangaroo, which uses its fine control and direct muscle action to propel it along; and ‘pause and leap’, like a grasshopper, which stores muscle energy in spring-like elements and rapidly releases it to make the jump.

‘We’ve made a robot that jumps in a similar way to the grasshopper, but uses electrical motors to slowly store the energy needed to leap in its springy skeleton. Before jumping, the robot squashes its spherical shape. When it is ready, it releases the stored energy all at once to jump to heights of up to half a metre,’ added Armour.

Future prototypes could include a stretchy skin covered in solar cells on the outside of the robot, so it could power itself, and robotic control sensors to enable it to sense its environment.

The components of the robot were made by rapid prototyping technology, similar to that used by the RepRap machine pioneered by the university, which builds parts by ‘printing’ layers of plastic on top of each other to produce a 3D object.