A tiny robot named MilliMobile, powered only by surrounding light or radio waves, could be used to catch gas leaks or track warehouse inventory, scientists have said.
Moving robots typically demand a lot of energy, which requires a battery that only has a limited lifetime.
Researchers at the University of Washington (UW) have created MilliMobile, which is equipped with a solar panel-like energy harvester and four wheels.
The robot is about the size of a penny, weighs as much as a raisin and can move roughly the length of a bus (approximately 10 metres) in an hour, even on a cloudy day.
The robot can also drive on surfaces such as concrete or packed soil and carry nearly three times its own weight in equipment, such as a camera or sensors. It uses a light sensor to move automatically toward light sources so it can run indefinitely on harvested power.
“We took inspiration from ‘intermittent computing,’ which breaks complex programs into small steps, so a device with very limited power can work incrementally as energy is available,” said co-lead author Kyle Johnson, a UW doctoral student.
“With MilliMobile, we applied this concept to motion. We reduced the robot’s size and weight so it takes only a small amount of energy to move. And, similar to an animal taking steps, our robot moves in discrete increments, using small pulses of energy to turn its wheels.”
The team tested the robot both indoors and outdoors, in environments such as parks, an indoor hydroponic farm and an office. Even in very low light situations – for example, only the lights under a kitchen counter – the robots are still able to inch along, albeit more slowly.
Running continuously, even at that pace, opens new abilities for a swarm of robots deployed in areas where other sensors have trouble generating nuanced data, the scientists said.
The robots are also able to steer themselves, navigating with onboard sensors and tiny computing chips. To demonstrate this, the team programmed them to use their onboard light sensors to move towards a light source.
“IOT sensors are usually fixed in specific locations,” said co-lead author Zachary Englhardt, a UW doctoral student.
“Our work crosses domains to create robotic sensors that can sample data at multiple points throughout a space to create a more detailed view of its environment, whether that’s a smart farm where the robots are tracking humidity and soil moisture, or a factory where they’re seeking out electromagnetic noise to find equipment malfunctions.”
Researchers have outfitted MilliMobile with light, temperature and humidity sensors, as well as with Bluetooth, letting it transmit data over 200 metres. In the future, they plan to add other sensors and improve data-sharing among swarms of these robots.
