Chinese scientists fuel low-altitude economy with sparkling innovations

BEIJING -- For Huang Xun, a professor at Peking University's College of Engineering, the vision of flying cars filling the sky, as seen in science fiction, may soon become a reality.

He likens the shift to the transition from horse-drawn carriages to cars a century ago, noting that human beings are about to enter the "low-altitude vehicle era".

More than 100 years ago, the United States seized the opportunity of automobile development to become a country on wheels. Now, China is seizing the opportunity of the low-altitude economy to become a country on wings, Huang said.

However, he warned that numerous challenges must be overcome before low-altitude vehicles can be widely adopted, citing safety concerns, such as potential collisions with drones, privacy issues related to drone sensors, and environmental impacts like noise pollution.

Huang's reflections were published in Nature last month, marking the first article on the low-altitude economy in the prestigious journal.

In fact, over the past years, Huang and his colleagues have been focused on finding solutions to these challenges and supporting the rapid growth of the low-altitude economy.

Build invisible roads

With the vision of airborne vehicles coming into reality, ensuring flight safety is paramount. Chinese scientists are working to establish "invisible roads" in the airspace below 3,000 meters to ensure orderly flight.

Qu Tengteng, a researcher at Peking University's College of Engineering, and her team developed a geospatial grid system to map low-altitude airspace.

The system converts three-dimensional spatial coordinates into binary codes, which are loaded into computers to create a real-time dense grid of airways. These invisible roads would help prevent collisions between low-altitude aircraft and avoid buildings.

"With this air road network, we can design traffic rules and add 'traffic lights' to avoid accidents," Qu said.

To enhance air safety further, Li Zhongkui, a professor at the college, developed an unmanned aircraft vehicle trajectory planning system.

Inspired by how birds in flocks coordinate with one another to avoid collisions, the system developed by Li uses swarm intelligence to regulate the movement of low-altitude vehicles both online and in real-time, ensuring they maintain safe distances and fly in harmony.

Size down engines

For long-distance air travel, low-altitude vehicles will need robust power sources. While current small drones rely on battery storage, future vehicles, which will carry heavier loads, will need more powerful engines.

"A major challenge with lithium batteries is their weight, which limits low-altitude flight capabilities," said Chen Zheng, deputy dean of Peking University's College of Engineering, adding that the energy density of batteries is two orders of magnitude lower than that of liquid fuels.

The team is exploring ways to miniaturize combustion engines for use in low-altitude vehicles. Wang Shengkai, an assistant professor at the college, said the goal is to develop high-power, stable combustion engines that could fit into various unmanned aerial vehicle (UAV) sizes.

"By scaling down the engine and optimizing the combustion process, we can create efficient, long-range propulsion systems for UAVs," Wang said. The team is also looking into environmentally friendly fuels, such as hydrogen and biomass, to reduce the carbon footprint.

Meanwhile, Zhao Hao, a colleague of Wang, has been working on monitoring and regulating combustion engines and power batteries for low-altitude vehicles using advanced fiber optics. Zhao explained that power safety is a major concern for these vehicles, and this innovation helps create intelligent UAVs with enhanced safety.

Mitigate noise pollution

As low-altitude vehicles proliferate, noise pollution will likely become a growing concern. To address this, Chinese scientists are working on technologies to minimize the noise generated by UAV rotors.

Lyu Benshuai, an assistant professor at the university's College of Engineering, and his team developed a rapid prediction model for rotor noise. The model helps predict how different blade shapes and configurations affect noise levels, allowing for more efficient noise-reduction designs.

"We can do quite a lot in aeroacoustic optimization. For example, rotors mounted at the rear of the fuselage are often much noisier than those at the front, while blades with suitable geometry and serration designs generate less noise," Lyu said.

The team is collaborating with Chinese tech companies like Huawei and Ecovacs to implement these noise-reducing innovations. "We hope to bring these scientific advances to market soon," Lyu added.

The low-altitude economy in China has flourished in recent years, with an increase in drone manufacturers and expanded applications. The Civil Aviation Administration of China estimates that the country's low-altitude market will reach 1.5 trillion yuan (about $209 billion) in 2025 and as much as 3.5 trillion yuan in 2035.

Chen revealed that their college plans to offer more practical courses related to low-altitude vehicles. These courses will include opportunities for students to design their own aircraft and collaborate with enterprises on co-designing projects. "We are planning ahead to meet the growing demand for talent in the future."

"We often ask, where is the next technological revolution after the industrial revolution? I believe the low-altitude economy could be the answer," Huang added.