Biology-inspired engineering
Rhodri Armour, a PhD student from the University of Bath, has created the ‘Jollbot’, a simple and sophisticated robot that has addressed some of the challenges faced by conventional robots. Armour, who will soon receive his Doctorate, did the project at Bath’s Centre for Biomimetic and Natural Technologies. His background was in mechanical engineering, but with an interest in Biology he was drawn to Biomimetics – engineering inspired by biology.

‘The main inspiration,’ says Armour, ‘comes from the prevalence of jumping in nature, when animals, and particularly insects, move across rough terrain.’ Conventional robots have trouble when faced with natural barriers, and robots with legs are complicated and cost more. Wheel-based robots are also limited.

Grasshopper
Armour had considered flying-robots but they would consume a high, continuous, source of energy. Because jumping is periodic it requires as less dense energy source that can possibly be amplified for a jump. ‘This is exactly what small animals do,’ says Armour. ‘When they jump, they amplify their muscle energy by storing the work from muscles in springy skeletal elements.’ The robot jumps like a grasshopper and stores the energy needed in a springy skeleton.

Speed isn’t essential to exploration but versatility is. Combining jumping and rolling adds a dimension. Because the robot had a spherically shaped energy store, Armour says that the shape encouraged him to ‘incorporate a powered rolling motion for movement over smooth surfaces.’

The main challenge in building the mechanism was combining the two types of motion in a single device. ‘Jumping requires lightness and a centre of gravity almost in the centre of the sphere,’ explains Armour, ‘whereas powered-rolling requires substantial mass toward the outside of the sphere.’

Flexible
The robot is mainly built in steel and plastic, using standard modeling parts like servo-motors, battery packs and receivers. ‘The outer skeleton is the energy store,’ says Armour, ‘and is made from spring steel elements.  The main chassis components are made from Rapid Prototyped (RP) plastic which are made directly from the computer aided design models.’ The resulting robot is flexible, small and weighs less than a kilogram.

Armour would love the opportunity to work with people to develop the idea. And where does the name come from? It comes from the combined Jumping and Rolling movement, resulting in Jollbot.’