Eye, Robot: Learning Expressive Gaze Dynamics via a VLM-Guided Transformer-VAE
Organizations: Creative Machines Lab, Department of Mechanical Engineering, Columbia University
Abstract
Gaze coordinates attention in human interaction through coupled eye, head, and eyelid motion. A humanoid robot must choose where to look while generating a suitable movement toward that target; fixed tracking rules alone do not model the temporal structure of human gaze. We separate these tasks with an asynchronous vision-language model that selects a scene referent, a reactive perception module that maintains fixation, and a Realistic Gaze Transformer (RGT) that generates target-conditioned motion. RGT is a Transformer-VAE trained on markerless human recordings retargeted to the robot's 11-DoF joint space: self-supervised pretraining encodes recent full-head history, and autoregressive fine-tuning exposes the model to its own predictions during rollout. At inference, a four-dimensional binocular-eye trajectory conditions coordinated neck and eye motion; an auxiliary blink predictor triggers eyelid templates during playback. On a two-second benchmark in which all controllers receive the same ground-truth target, RGT-Base obtains the lowest reported overall seven-joint MSE, and physical demonstrations show the integrated targeting and control pipeline. The evidence establishes robot-space kinematic fidelity and real-time RGT inference; perceived naturalness and open-vocabulary target-selection accuracy remain questions for controlled evaluation.
Figures & tables
| Method | BID 1 | BID 2 | BID 3 | BID 4 | BID 5 | BID 6 | Overall |
|---|---|---|---|---|---|---|---|
| Head-Only | 5.8e-2 | 5.9e-2 | 7.3e-2 | 7.2e-2 | 7.2e-2 | 6.8e-2 | 6.8e-2 |
| Eye-Only | 5.1e-2 | 5.4e-2 | 5.7e-2 | 5.6e-2 | 5.5e-2 | 5.2e-2 | 5.2e-2 |
| Eye-Head Coord. | 1.3e-2 | 1.2e-2 | 3.9e-2 | 1.5e-2 | 1.7e-2 | 1.4e-2 | 1.8e-2 |
| Head-Only (w/o fixed) | 1.6e-2 | 1.3e-2 | 5.8e-2 | 2.3e-2 | 3.2e-2 | 2.1e-2 | 3.1e-2 |
| Eye-Only (w/o fixed) | 1.7e-2 | 1.8e-2 | 1.5e-2 | 2.3e-2 | 1.1e-2 | 1.6e-2 | 1.7e-2 |
| RNN | 1.3e-4 | 2.0e-4 | 1.6e-4 | 2.2e-4 | 3.7e-4 | 9.8e-4 | 3.0e-4 |
Appendix figures & tables3 assets
Supplementary material from the paper’s appendix.
Appendix
| Method | BID 1 | BID 2 | BID 3 | BID 4 | BID 5 | BID 6 | Overall |
|---|---|---|---|---|---|---|---|
| RNN | 8.6e-5 | 1.3e-4 | 1.2e-4 | 1.9e-4 | 3.2e-4 | 9.9e-4 | 2.6e-4 |
| VAE-CNN | 1.2e-5 | 1.5e-5 | 3.7e-5 | 2.0e-5 | 5.2e-5 | 4.8e-4 | 8.7e-5 |
| Flow Matching (16-step) | 4.2e-6 | 1.0e-5 | 1.4e-5 | 2.6e-5 | 1.9e-5 | 1.9e-5 | 1.2e-5 |
| RGT-Base | 1.6e-5 | 2.5e-5 | 3.8e-5 | 3.9e-5 | 9.5e-5 | 3.9e-4 | 8.5e-5 |
| RGT-Large | 1.4e-5 | 2.1e-5 | 4.1e-5 | 2.9e-5 | 8.9e-5 | 6.0e-4 | 1.1e-4 |
| RGT-Small | 1.4e-5 | 2.3e-5 | 4.3e-5 | 3.2e-5 | 8.5e-5 | 6.5e-4 | 1.2e-4 |
| Behavior (Subject) | Description | Rows |
|---|---|---|
| Behavior 1 (Subject 1) | This sequence mimics natural human eye tracking behavior. The head oscillates within 10 ∘ , while the eyes move in coordination, turning left and right with an anticipatory expression. | 31487 |
| Behavior 2 (Subject 1) | Similar to Behavior 1, this sequence replicates eye tracking behavior but over a shorter duration. The head and eye motions follow the same pattern. | 26739 |
| Behavior 3 (Subject 1) | This sequence captures a Head-Down Scan gesture. The motion begins by lowering the head approximately 30 ∘ , followed by a slow left-right head rotation of about 15 ∘ , expressing contemplation. | 8358 |
| Behavior 4 (Subject 1) | This sequence represents a Head-Up Survey gesture. The head raises approximately 45 ∘ and then moves left and right, coordinated with eye movements, expressing alertness. | 6750 |
| Behavior 5 (Subject 1) | This sequence features a Head-Mid Survey , using head oscillations within 10 ∘ along with coordinated eye movements. | 10014 |
| Behavior 6 (Subject 1) | This sequence follows an All Survey pattern, combining head oscillations within 10 ∘ and coordinated eye movements to express anticipation. | 14310 |
Robot Motion Generation
Robot motion generation creates feasible, task-directed trajectories for robots to move, manipulate objects, and interact with people and environments.
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