Methods and systems for autonomously interacting with persons in a public environment to store and transport their personal material items are described herein. A service robot includes one or more secure storage cells, and is configured to collect items such as personal belongings, refuse, etc., from users and transport the collected items to different locations. The service robot maneuvers through a crowded environment autonomously, avoiding collisions with people and objects, and minimizing disturbances to traffic flow. Users indicate a desire to store and transport items to a desired location. In response, the service robot unlocks a lid of a storage cell, and the user is able to load material items. In some examples, access to the storage cell is controlled based on access codes. In some examples, access to the storage cell is controlled based on receipt of an electronic payment.