He now leads his own home robot company, Hoaloha Robotics, which is focused on a mobile robot to permit older people to live independently at home. Mr. Trower said that while he remained optimistic that in the long run he would be able to develop a robot that acted as a partner or an assistant for aging people, he realized that a commercial product was not on the near horizon.

Despite those repeated failures, many technologists remain optimistic that the home robot is just around the corner.

At Stanford University, which pioneered the original robot arm and first mobile robot in the 1960s, the roboticist Kenneth Salisbury developed the prototype PR1 home robot a decade ago.

The PR1 inspired Willow Garage, a start-up funded by Scott Hassan, one of Google’s original programmers. Willow Garage produced another prototype home robot, the PR2, which led to a number of spinoffs, but no successful commercial home applications emerged from the research.

Both the PR1 and PR2 were early explorations in performing common household tasks like getting a cup of coffee, loading and unloading the dishwasher, and going to the refrigerator and getting a beer. The robot prototypes performed these tasks, but only in highly controlled experiments.

Now, Stanford roboticists are working on a next-generation robot that could potentially work in the home. Silvio Savarese, a Stanford computer scientist, is leading a team developing a robot called JackRabbot, intended for home or campus delivery as well as some tasks in the home. But getting around a house is still difficult, even in a ranch house without stairs, he said.

Self-driving cars’ engineers use the technology “simultaneous localization and mapping,” or SLAM, to navigate. It makes it possible to create a map in an unknown environment and place the car accurately. But in a home, with densely packed objects, including humans, that move frequently, SLAM is insufficient, Mr. Savarese said.