Most of the retail robots have just enough human qualities to make them appear benign, but not too many to suggest they are replacing humans entirely.

“It’s like Mary Poppins,” said Peter Hancock, a professor at the University of Central Florida, who has studied the history of automation. “A spoonful of sugar makes the robots go down.”

Perhaps no other retailer is dealing as intensely with the sensitivities around automation as Walmart, the nation’s largest private employer, with about 1.5 million workers. The company spent many months working with the firm Bossa Nova and researchers at Carnegie Mellon University to design a shelf-scanning robot that they hope both employees and customers will feel comfortable with.

This robot was designed without a face, because its developers did not want customers to think they could interact with the device. But many of the robots have names, given to them by store staff. Some also wear name badges.

“We want the associates to have an attachment to it and want to protect it,” said Sarjoun Skaff, a co-founder and the chief technology officer at Bossa Nova. Walmart said it planned to deploy the robots in 1,000 stores by the end of the year, up from about 350.

At the Walmart Supercenter in Phillipsburg, N.J., on the Pennsylvania border, employees named the robot Wall-E — a choice partly inspired by the Pixar film that depicts a trash-collecting robot on a deserted planet.

The robot can work 365 days a year, scanning shelves with high-resolution cameras tabulating out-of-stock items. It takes a short break between shifts to recharge its batteries in a docking station.