BeanBot: Motorless Robot Hops Like Mexican Jumping Bean

Researchers at the Italian Institute of Technology have engineered a novel robot, designated BeanBot, drawing inspiration from the unpredictable motion of Mexican jumping beans. This device operates without traditional motors, batteries, electronics, or onboard computing. Its movement depends solely on its interaction with its immediate environment, allowing it to hop, roll, flip, or slide in unpredictable ways. This represents a different approach to robotic locomotion.

Credit: BeanBot

Research conducted by the Italian Institute of Technology's Bioinspired Soft Robotics department led to the development of BeanBot, a small robot capable of jumping, rolling, flipping, sliding, and climbing slopes. The inspiration came from the Mexican jumping bean, whose distinctive movements are generated by a moth larva within a seed pod. Instead of directly replicating the animal, the team combined the bean's heat driven movement with its shell's shape. This design enables the robot to exhibit several distinct behaviours.

And BeanBot comprises two primary components, a small heat responsive spring and a lightweight, bean shaped shell. The spring, constructed from a shape memory alloy, changes its form when subjected to heat. Magnets secure this spring, permitting it to store energy. When the spring attains a sufficient temperature, it releases this energy abruptly, propelling the robot upwards. The shell then directs the subsequent action.

The robot lacks an internal system dictating its movements, such as when to jump, roll, or flip. Its physical shape and the surface it rests upon primarily determine its motion. The shell features one curved side and two flat sides, facilitating varied interactions with the ground. The curved section enables rolling, while the flat sides contribute to stability and aid in ascending inclines. This design also assists the robot in righting itself after landing, preparing for another jump.

But this straightforward design grants BeanBot a wide array of movements. Researchers observed the robot could jump approximately 30 centimetres high, roll for distances of about 80 centimetres, slide across smooth surfaces, and flip either in the air or upon impact. It also demonstrated an ability to climb slopes between 10 and 18 degrees, provided its magnetic force was adjusted. These actions all stem from the same heat powered spring.

The robot's behaviour adapts according to the surface it encounters. On a smooth surface, an initial jump might result in predominantly vertical travel or a slide. A rougher terrain can induce rolling, while irregular ground alters the trajectory and height of its jumps. Trials involving 92 jumps revealed that approximately 81.5 per cent led to additional movements, including rolling, sliding, bouncing, or flipping. This indicates that the robot's surroundings function as an integral part of its movement system.

So BeanBot presents as a notably simpler construction compared to conventional robotic systems. Its shell weighs roughly 3.8 grams, and the jumping module accounts for about 8 grams. The entire assembly incorporates a 3D printed shell, the shape memory alloy spring, and magnets. Crucially, no onboard electronics are required for managing its movements.

However, the current design has inherent limitations. The shape memory alloy spring necessitates temperatures ranging from 70 to 80°C to initiate a jump. Furthermore, the robot requires between 30 and 180 seconds to activate and a recovery period of 130 to 140 seconds before it can commence another cycle. Researchers anticipate that advancements in material science could allow BeanBot to operate at lower temperatures and with quicker cycle times.

The creators view BeanBot as an illustration of an alternative approach to robotics. This method proposes that a robot's physical structure can undertake functions typically handled by sensors, computers, and dedicated software. Rather than programming each specific movement, the robot's design, materials, and interaction with its environment inherently generate a variety of behaviours. This eliminates the need for complex control algorithms in certain applications.

• BeanBot operates without conventional motors, batteries, or computing.

• Its movement is driven by a heat responsive shape memory alloy spring.

• The robot's shell design and interaction with surfaces determine its motion.

• Capabilities include jumping, rolling, sliding, flipping, and climbing inclines.

• Current limitations involve activation temperature and recovery time.

Source: Interesting Engineering