A robot delivers meals to a customer at an Asian restaurant in Vienna, Austria, on May 28, 2020. An Asian restaurant in Vienna uses robots to deliver meals in order to reduce unnecessary contact between waiters and customers during the COVID-19 outbreak. (Xinhua/Guo Chen)

A robot delivers meals to a customer at an Asian restaurant in Vienna, Austria, on May 28, 2020. An Asian restaurant in Vienna uses robots to deliver meals in order to reduce unnecessary contact between waiters and customers during the COVID-19 outbreak. (Xinhua/Guo Chen)

A robot delivers meals at an Asian restaurant in Vienna, Austria, on May 28, 2020. An Asian restaurant in Vienna uses robots to deliver meals in order to reduce unnecessary contact between waiters and customers during the COVID-19 outbreak. (Xinhua/Guo Chen)

A robot delivers meals at an Asian restaurant in Vienna, Austria, on May 28, 2020. An Asian restaurant in Vienna uses robots to deliver meals in order to reduce unnecessary contact between waiters and customers during the COVID-19 outbreak. (Xinhua/Guo Chen)

A robot delivers meals at an Asian restaurant in Vienna, Austria, on May 28, 2020. An Asian restaurant in Vienna uses robots to deliver meals in order to reduce unnecessary contact between waiters and customers during the COVID-19 outbreak. (Xinhua/Guo Chen)

A waiter sets the table number for the robot delivery at an Asian restaurant in Vienna, Austria, on May 28, 2020. An Asian restaurant in Vienna uses robots to deliver meals in order to reduce unnecessary contact between waiters and customers during the COVID-19 outbreak. (Xinhua/Guo Chen)