Once a niche appliance, robot vacuum cleaners have become a test of whether Samsung Electronics and LG Electronics can regain ground in a fast-growing Korean market increasingly shaped by Chinese rivals. China's strength in the sector is reflected in trade data. Figures from the General Administration of Customs of China showed China exported 11.32 billion yuan ($1.67 billion) worth of robots in the first quarter. Cleaning robots, a category newly added to customs product codes this year, accoun