Robotic vacuum cleaners, washer dryers and dishwashers are popular among two-income households, as they afford families more free time by relieving them of daily chores, according to electronics makers and retailers. Electronics chain Bic Camera Inc. said the number of robot cleaners it sold in the first half of 2017 increased 20 percent from the year before. U.S. manufacturer iRobot Corp. has introduced low-end Roomba robot vacuums priced below ¥60,000 with a system that allows users to control the machine with their smartphones. The system was previously limited to high-end models. Hitachi Ltd. and Panasonic Corp. are among the Japanese firms offering robot cleaners, with their products sold mainly in the ¥60,000 range.