As Web-based video becomes more prominent as a teaching tool, special education advocates say these robots are valuable alternatives to tutoring. About 23,000 students across the country are homebound or hospitalized each school year. They might not otherwise interact with classmates or could fall farther behind academically, advocates say.

“Soon, these robots should be the price of an inexpensive laptop,” said Maja Mataric, a computer science professor at the University of Southern California, who studies how robots help children with learning disabilities. “They should make access to education much easier for students who are convalescing.”

Dr. Mataric’s research focuses on using robots to teach social cues to children with autism. Children adapt far more quickly to the technology than adults and treat the machine like another classmate, she says. During a fire drill at one Texas school, students were so worried about the VGo that they insisted on escorting it out of the building to safety.

The VGo is four feet tall, weighs 18 pounds and is shaped like a white chess pawn, with a video screen on its face. Lexie controls its movement with her computer mouse. Video of the classroom at Alice Drive Elementary School appears on her computer screen, and video of her face appears on the robot’s display screen. The robot and Lexie’s computer support two-way voice communication, and Lexie can flash her VGo’s lights to get the teacher’s attention.