Chinese customers' growing appetite for robotic vacuum cleaners is drawing a renewed technology competition from the world's biggest brands, stuffing the mini-housekeepers with increasingly sophisticated sensors and software for tasks from smart routing to language processing and mobile communications.

The latest war of innovation was ignited by a reviving demand of robot vacuums from last year, after the pandemic lifted the hygiene standards of many strained at home. Total sales of the cleaning robots in China increased 19.1 percent in 2020 to 9.4 billion yuan (about $1.46 billion), recovering from a dip in 2019, according to data from research firm China Market Monitor (CMM) and cheaa.com, a home appliance portal website.

Globally, the International Federation of Robotics estimated 31 million household robots were sold from 2016 to 2019, 96 percent of which are vacuum and floor-cleaning robots. The robotic vacuum cleaner market is expected to increase at a compound annual growth rate of 13 percent from 2021 to 2026, according to ResearchAndMarkets.com, a leading market research platform.

After meeting the basic cleaning requirement, the development of next-generation vacuum cleaners is focused on more advanced technologies including artificial intelligence, cloud computing human-machine interaction and coordination among different machines, said a white paper released by cheaa.com, operated by the China Household Electrical Appliance Association.

"The technology upgrades turned vacuum robots into matured products from a high-end category after local brands such as Ecovacs and Xiaomi introduced robots at more reasonable prices," said the white paper.

Ecovacs Robotics, the first company to enlist AI and visual recognition to robot learners, dominated the Chinese market last year, according to the white paper. It controlled 46.9 percent of the online market and owns a whopping 71.3 percent market share from brick-and-mortar sales, data from CMM showed. Local players Xiaomi and Roborock also hold sizable online market shares as their functionality and design appeal to young buyers.

Laser technology is becoming an essential in top-tier products. Using a tailored algorithm, the robot translates laser feedback into a three-dimensional model of the surroundings so it can identify items such as table legs, pets and socks and avoid collisions.

In early 2020, Ecovacs introduced a product that is mounted with a laser system and a camera module that allows the robot to detect objects twice as far away. Its detection accuracy of small objects also increased by four times compared to previous products, the company said.

Xiaomi also highlights how far its products can see. Using a similar laser and camera setup, the Beijing-based company claims its robot can detect objects 10 meters away. In addition, taking advantage of its Siri-like AI voice assistant XiaoAI, users can give vocal orders to the robot to recharge itself, start or pause cleaning.

Roborock's latest rollout looks downward. Developers placed an ultrasonic sensor underneath the robot to detect carpet. The robot then uploads the information to the user's apps so they can either order the robot to stay away from the carpet or clean the carpet with its vacuum function.

"It's becoming increasingly important for players to find their strengths to distinguish themselves from competition," said the white paper.