AI-Powered Robot Navigates Home Using Language

Researchers have developed an AI system that guides robots using language-based instructions, improving navigation tasks without relying on extensive visual data. The method converts visual observations into text captions, allowing a language model to direct the robot’s movements. While not outperforming vision-based systems, it excels in data-limited scenarios and combines well with visual inputs for better performance.

Key Facts:

• AI system uses text captions to guide robot navigation.
• Language-based approach reduces the need for extensive visual data.
• Combining language and vision improves navigation accuracy.

Imagine asking your home robot to carry a load of dirty clothes downstairs and deposit them in the washing machine in the far-left corner of the basement. The robot will need to combine your instructions with its visual observations to determine the steps it should take to complete this task.

For an AI agent, this is easier said than done. Current approaches often utilize multiple hand-crafted machine-learning models to tackle different parts of the task, which require a great deal of human effort and expertise to build. These methods, which use visual representations to directly make navigation decisions, demand massive amounts of visual data for training, which are often hard to come by.

To overcome these challenges, researchers from MIT and the MIT-IBM Watson AI Lab devised a navigation method that converts visual representations into pieces of language, which are then fed into one large language model that achieves all parts of the multistep navigation task.

“By purely using language as the perceptual representation, ours is a more straightforward approach. Since all the inputs can be encoded as language, we can generate a human-understandable trajectory,” says Bowen Pan, an electrical engineering and computer science (EECS) graduate student and lead author of a paper on this approach.

Solving a Vision Problem with Language

The researchers sought to incorporate large language models into the complex task known as vision-and-language navigation. But such models take text-based inputs and can’t process visual data from a robot’s camera. So, the team needed to find a way to use language instead.

Their technique utilizes a simple captioning model to obtain text descriptions of a robot’s visual observations. These captions are combined with language-based instructions and fed into a large language model, which decides what navigation step the robot should take next.

The large language model outputs a caption of the scene the robot should see after completing that step. This is used to update the trajectory history so the robot can keep track of where it has been.

The model repeats these processes to generate a trajectory that guides the robot to its goal, one step at a time.

Caption: Robot navigation using language

Advantages of Language

When they tested this approach, while it could not outperform vision-based techniques, they found that it offered several advantages. First, because text requires fewer computational resources to synthesize than complex image data, their method can be used to rapidly generate synthetic training data. In one test, they generated 10,000 synthetic trajectories based on 10 real-world, visual trajectories.

The technique can also bridge the gap that can prevent an agent trained with a simulated environment from performing well in the real world. This gap often occurs because computer-generated images can appear quite different from real-world scenes due to elements like lighting or color. But language that describes a synthetic versus a real image would be much harder to tell apart.

Also, the representations their model uses are easier for a human to understand because they are written in natural language.

“If the agent fails to reach its goal, we can more easily determine where it failed and why it failed. Maybe the history information is not clear enough or the observation ignores some important details,” Pan says.

In addition, their method could be applied more easily to varied tasks and environments because it uses only one type of input. As long as data can be encoded as language, they can use the same model without making any modifications.

But one disadvantage is that their method naturally loses some information that would be captured by vision-based models, such as depth information.

However, the researchers were surprised to see that combining language-based representations with vision-based methods improves an agent’s ability to navigate.

“Maybe this means that language can capture some higher-level information than cannot be captured with pure vision features,” he says.

This is one area the researchers want to continue exploring. They also want to develop a navigation-oriented captioner that could boost the method’s performance. In addition, they want to probe the ability of large language models to exhibit spatial awareness and see how this could aid language-based navigation.