AGV (automated guided vehicle) robots line up to serve food to customers in a smart restaurant operated by Chinese e-commerce giant Alibaba at the National Exhibition and Convention Center in east China's Shanghai, Oct. 15, 2018. (Xinhua/Fang Zhe)

A customer takes food served by an AGV (automated guided vehicle) robot in a smart restaurant operated by Chinese e-commerce giant Alibaba at the National Exhibition and Convention Center in east China's Shanghai, Oct. 15, 2018. (Xinhua/Fang Zhe)

Customers take photos of an AGV (automated guided vehicle) robot serving food in a smart restaurant operated by Chinese e-commerce giant Alibaba at the National Exhibition and Convention Center in east China's Shanghai, Oct. 15, 2018. (Xinhua/Fang Zhe)

An AGV (automated guided vehicle) robot serves food to customers in a smart restaurant operated by Chinese e-commerce giant Alibaba at the National Exhibition and Convention Center in east China's Shanghai, Oct. 15, 2018. (Xinhua/Fang Zhe)