A research team in China said it used a solar-powered brain control device to steer a pigeon in flight for nearly two hours on a sunny day.
The scientists, led by Huai Ruituo, a professor with the college of electrical and automation engineering at Shandong University of Science and Technology in eastern China, are studying the use of robotics in animals.
According to a paper published in China’s peer-reviewed Journal of Biomedical Engineering, the researchers strapped a solar panel about half the size of a smartphone screen to a pigeon’s back.
A small lithium battery charged by the panel then powered a brain control device on the bird’s head, generating nerve stimulating signals while maintaining wireless communication with the home base.
With the new device, “the animal robot can be guided to charge in the sun autonomously if the remaining power is low”, Huai and her colleagues wrote in the paper. They could not immediately be reached for comment.
The researchers noted that in previous experiments, pigeons followed human commands for about 45 minutes – a similar duration to a typical commercial drone because of the limited size of battery the birds could carry.
“The results show that for animals that are active outdoors, such as domestic pigeons, the running time is greatly extended after the system is installed, and they can perform tasks in farther places without worrying about the problem of energy exhaustion,” they said.
The first successful experiments in animal brain control were reported by a Japanese research team in 1997, in a presentation to an international robotics conference. They used electrical stimuli to keep a cockroach moving in a straight line.
Since then, many researchers from around the world have joined the field, extending the use of similar technology to a wide range of animals, including beetles, bees, geckos, rats and sharks.
Western countries have been taking the lead, but China has caught up rapidly in recent years, with breakthroughs including controlled movement of a swarm of animals and an automatic guidance system using GPS and image recognition to direct an animal to a location without human intervention.
The animals’ behaviours are usually manipulated through neural signals generated by the researchers to trigger unpleasant sensations such as pain or fear, prompting an immediate action such as turning right or left.
To function properly, the signal generator, computer chips and communication components for the brain control device require a constant, stable energy supply.
Overcoming the constraints of a limited energy supply is a major challenge preventing the technology from being applied to real-life scenarios including search and rescue efforts after a disaster and military operations.
Huai’s team said their solar-powered system had been built with mostly off-the-shelf components. It was not the most efficient energy source, and the low-cost computer chip in the brain control device also consumed more power than they would have liked.
To overcome these challenges, the scientists developed a smart power management system that closely monitored the brain control system and predicted its energy consumption, which increased energy efficiency, they said.
Using the forecasts, the brain control device can change the intensity of its stimulating signals and coordinate energy distribution to the different components to maximise an operation’s duration in a constantly changing environment.
The researchers said their study found the system could increase the effective power supply time by nearly 40 per cent, even on a cloudy day.
The team’s experiments with five pigeons showed the birds could follow simple orders – such as turning to the right or left with 80-90 per cent accuracy. The researchers said the birds were sometimes unresponsive because of fatigue or strong, unexpected distractions in the open environment.
Huai said the device’s performance could be improved through the use of artificial intelligence to reduce the burden of data collection and calculation. Better solar panels would also increase the conversion rate of sunlight to electricity, she said.
A Beijing-based researcher studying the use of robotics in animals said the technology – which usually requires the surgical implant of wires into an animal’s brain had potential uses in some military applications.
Some of the leading research projects in the field had been funded by the US Defence Advanced Research Projects Agency (DARPA) and China’s People’s Liberation Army, said the researcher, who asked for anonymity because of the issue’s sensitivity.
These included the development of brain-controlled animals to carry intelligence gathering instruments or weapons in dangerous situations such as anti-terrorist operations or combat missions, the researcher said.
According to the researcher, the PLA and DARPA had considered several energy supply methods, including using the animal’s blood sugar or their muscle movements to generate electricity, as well as wireless power transmission.
But these systems were rather complex, the researcher said. In contrast, a solar panel offered a simple engineering solution although it could add weight and reduce the animal’s mobility and its value in practice required further investigation.