Objects play an especially important role in people's lives. Objects within human environments are usually found on flat surfaces that are orthogonal to gravity, such as floors, tables, and shelves. EL-E is an assistive robot that is explicitly designed to take advantage of this common structure in order to retrieve unmodeled, everyday objects for people with motor impairments. EL-E incorporates two key innovations.
First, EL-E is equipped with a laser pointer interface that detects when a user illuminates a location with an off-the-shelf green laser pointer and estimates its 3D position. This enables a user to unambiguously communicate a 3D location to the robot using a point-and-click style of interaction, which provides a direct way to tell the robot which object to manipulate or where to go.
Second, EL-E is able translate its manipulator and associated sensors to different heights, which enables it to grasp objects on a variety of surfaces, such as the floor and tables, using the same perception and manipulation strategies. The robot can approach an object selected with the laser pointer interface, detect if the object is on an elevated surface, raise or lower its arm and sensors to this surface, and visually and tactily grasp the object. Once the object is acquired, the robot can place the object on a laser designated surface above the floor, follow the laser pointer on the floor, or deliver the object to a seated person selected with the laser pointer.