TalkToWalk

Text-guided visual navigation of a humanoid robot

Give a humanoid robot directions the way you would give them to a person: “go straight, and at the next junction turn right”. TalkToWalk aims to fine-tune a vision-language-action (VLA) model, such as NVIDIA GR00T N1, so that a Unitree G1 can walk such a route through a real building, guided by its camera and the text alone, without collisions.

Work in progress: planning phase

Bachelor’s thesis, Comenius University Bratislava, 2026–2027

Floor plan with the target route A rectangular loop of corridors around a block of rooms, with side corridors at the top and at the bottom. The route starts on the bottom corridor, passes six junctions, turns right four times and ends where it started. Start

Go straight. At the next junction, turn right, then right again, go straight, turn right, turn right and stop where you started.

Robot
Unitree G1 humanoid
Base model
NVIDIA GR00T N1 (VLA)
Training
Isaac Sim, then the real robot
Tools
Python, PyTorch, ROS 2

What the robot should learn

Humanoid robots are increasingly controlled by vision-language-action (VLA) models: networks that look at camera images, read an instruction and output actions. Open foundation models such as GR00T N1 are trained mostly for manipulation with the hands. This thesis adapts one of them to a different job: walking through a specific building along a route that is described only in words.

Input

Camera image

What the robot sees right now.

Input

Route in text

The command it is following, for example “at the next junction, turn right”.

Model

Fine-tuned VLA model

GR00T N1, with an extra output head that recognizes junctions.

Output

Walking commands

Walk forward, turn, stop. The G1’s own controller keeps the robot balanced.

Feedback during fine-tuning

LiDAR distances keep the robot clear of walls, people and other obstacles. Corrections from a person show what a good run looks like.

Planned approach

The design is not final. This is the current plan, and it will change as the first experiments come in.

  1. Write the route

    The route is a short sequence of commands, such as “go straight”, “at the next junction turn right” and “stop”.

  2. Look

    At every step the model gets the current camera frame together with the command it is following.

  3. Decide

    A fine-tuned GR00T N1 turns the image and the command into a walking action. An extra output head answers one question: am I at a junction right now?

  4. Move to the next command

    At a junction the robot carries out the current command (straight, left or right), and the next command in the sequence becomes the model’s input.

  5. Walk

    The action goes to the G1’s built-in walking controller through Unitree SDK2 and ROS 2, so the model never has to balance the robot itself.

  6. Stay clear and improve

    LiDAR measures the distance to walls, people and other static or moving obstacles. Together with corrections from a person, it gives the feedback for fine-tuning.

What counts as a junction

A place where the robot has a real decision to make:

  1. it can continue in at least two different directions, or
  2. it cannot continue straight ahead.
  • Side corridor rule 1
  • Crossroads rule 1
  • Corner rule 2

Recognizing junctions reliably is the first research milestone, because every command in the route is tied to one.

Training plan

  • Simulation first

    Most of the work happens in NVIDIA Isaac Sim, with a model of the G1 and of the building’s corridors.

  • Data

    From simulation and from a few routes walked with the real robot under manual or semi-manual control.

  • Learning

    Supervised learning, reinforcement learning or a combination of both; not decided yet.

  • Final test

    A full lap of the corridor loop in the faculty building, with static and moving obstacles.

Roadmap

Planned submission: spring 2027. This list is updated as the work moves on.

  1. Done

    Topic and literature review

    Thesis assigned in October 2026; the core papers on VLA models and humanoid navigation reviewed.

  2. Next

    Getting to know the G1

    Power and safety routine, the ROS 2 interface, streaming the camera and LiDAR, high-level walking commands.

  3. Planned

    Simulation

    The G1 and a corridor environment in NVIDIA Isaac Sim.

  4. Planned

    Junction detection

    A dataset from simulation and real routes; an extra output head on GR00T N1.

  5. Planned

    Text-guided navigation

    Fine-tuning GR00T N1 to follow a sequence of commands.

  6. Planned

    Real-world test

    A full lap of the corridor loop in the faculty building, with static and moving obstacles.

  7. Planned

    Thesis and release

    The written thesis; code and, where possible, data and models published in this repository.

Key literature

The three papers the thesis builds on, as listed in the thesis assignment.

  1. J. Björck et al., NVIDIA, 2025

    GR00T N1: An Open Foundation Model for Generalist Humanoid Robots

    arXiv:2503.14734

    The model to fine-tune. A slow vision-language “System 2” understands the scene and the instruction; a fast diffusion-transformer “System 1” turns that into motor actions.

  2. Collision-free local navigation on the same robot, the Unitree G1, with attention guided by predicted waypoints.

  3. D. Shah et al., CoRL 2023

    ViNT: A Foundation Model for Visual Navigation

    PMLR 229, pp. 711–733

    Shows that a pre-trained navigation model can be adapted cheaply to new environments and new kinds of goals, including directions such as “turn left”.

Previous work

This thesis builds on experience from my year project, where I built a reinforcement learning pipeline from scratch.

Year project at FMFI UK, page in Slovak

PyTorch Game Agent

From a DQN agent for Snake to a full CNN and Monte Carlo tree search self-play pipeline for the Kaggle Hungry Geese competition, benchmarked against a gold-medal public agent. The experience with training loops, self-play and careful evaluation carries straight over to this thesis.

  • 102 self-play iterations
  • 1.74 M training positions
  • 65.7 hours of training
  • 13,400 lines of code

Cite this work

The thesis is still being written. If you build on this repository before it is finished, please cite it as:

BibTeX

@misc{monis2026talktowalk,
  author       = {Moni{\v{s}}, D{\'a}vid},
  title        = {{TalkToWalk}: Text-Guided Visual Navigation of a Humanoid Robot},
  year         = {2026},
  howpublished = {\url{https://github.com/DavidMonis/talk-to-walk}},
  note         = {Bachelor's thesis in preparation, Comenius University Bratislava}
}