Microsoft Research publishes Rho, open-weight vision-language-action models for robots

Microsoft Research published the technical report for Rho on September 29, 2026. Rho is a family of vision-language-action models of about 5 billion parameters for two-armed robot manipulation, combining a Phi-family vision-language backbone with an action module. The models include a base model and checkpoints adapted to three robot platforms (I2RT YAM Box, Universal Robots UR AI Trainer, and Franka FR3 Duo). Their weights are on Hugging Face and the fine-tuning and adaptation code is on GitHub, both under the MIT license.1234