Video Overview

Joint vision-tactile prediction for robot policy evaluation and learning.

Real robot recordings

Tactile Textures

Distinct tactile patterns from grasping different objects.

Wrist View

Left hand
GTLeft grasp
Marker Disp.0.0000

90th percentile XYZ displacement · native units

Shaft

Contact selection
Representative test tube, isolated from its background

Representative object · schematic robot pose

Grasp, handover and right-hand reorientation.

Tactile Response

Two paired surfaces
Surface 0
Surface 1

Sensor-plane marker arrows · display scale ×5

0.0 / 4.0 s

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PhysCanvas

Overview

PhysCanvas: contact-rich tasks, a unified visual-tactile world model, joint generation, and policy evaluation and learning.

PhysCanvas maps multi-view RGB observations, tactile images, marker displacement, task state, and actions into a unified visual space. Conditioned on projected robot motion and reference observations, the model jointly predicts visual and tactile futures. Reward-based supervision supports consistent interactions, enabling robot policy evaluation and learning through imagined rollouts.

Framework

PhysCanvas framework: a unified multimodal world model conditioned on projected robot motion, reward model training, and consistency-aware world model post-training.

Unified multimodal generation. PhysCanvas combines multi-view RGB, tactile images, marker displacement, and task state in a unified canvas. A shared video VAE and Wan 2.2 predict future observations, conditioned on projected robot motion, an initial RGB anchor, and updated reference observations.

Consistency-aware post-training. Scene, Modality, and State Reward Models are trained using expert data and world-model rollouts. These reward models are then frozen to guide post-training toward scene consistency, visual-tactile compatibility, and agreement between predicted task state and task outcomes.

Feature Projection

Modality structure before and within the world model.

After VAE

Transformer block 1

Transformer block 15

Transformer block 30

Multi-view RGB, tactile images, marker displacement, and task state are projected into the same visual space; the panels show clean VAE latents and self-attention Value projections, with colors indicating source modality.

WM Prediction

Ground truth and model predictions across contact-rich tasks.

Baseline Comparison

Selected baseline failure cases and favorable PhysCanvas examples, not paired across methods. These qualitative examples do not estimate overall performance or success rates.

EVAC

Test tube
OverheadLeft wristRight wrist
Small rack details deform in wrist views.
Bottle
OverheadLeft wristRight wrist
Soft boundaries around the cap and gripper.
Blocks
OverheadLeft wristRight wrist
Bag openings and folds change shape.
Rubik's Cube
OverheadLeft wristRight wrist
Rubik's Cube sticker boundaries become soft during rotation.

Open-Sora

Test tube
OverheadLeft wristRight wrist
Fine rack and gripper boundaries become blurred.
Bottle
OverheadLeft wristRight wrist
Fine bottle and gripper details become smooth.
Blocks
OverheadLeft wristRight wrist
Bag and block surface details become smooth.
Rubik's Cube
OverheadLeft wristRight wrist
Rubik's Cube face geometry and fine detail deform.

WoVR

Test tube
OverheadLeft wristRight wrist
Rack appearance and brightness change over time.
Bottle
OverheadLeft wristRight wrist
Noticeable appearance and illumination drift.
Blocks
OverheadLeft wristRight wrist
Bag edges and background appearance drift.
Rubik's Cube
OverheadLeft wristRight wrist
Strong appearance changes in Rubik's Cube and wrist views.

PhysCanvas

Test tube
OverheadLeft wristRight wrist
Retained rack structure and scene appearance.
Bottle
OverheadLeft wristRight wrist
Stable tabletop appearance and visible cap detail.
Blocks
OverheadLeft wristRight wrist
Visible block colors and bag boundaries.
Rubik's Cube
OverheadLeft wristRight wrist
Visible face colors and coherent rubik's cube geometry.

Policy Evaluation

World-model versus real-world success rates on Test tube, Bottle, Blocks and Rubik's Cube, comparing WM and WM with state supervision.
Each point compares world-model and real-world success rates for one evaluation batch. State supervision improves agreement across four tasks, increasing mean task-wise Pearson correlation from 0.602 to 0.885. The dotted diagonal indicates ideal agreement.

Policy Learning

Table 4: Real-world success rates for FM and pi 0.5 with SFT, RL in WM, and RL in WM plus reward models, across four tasks.
Real-world policy success rates (%) after supervised fine-tuning or reinforcement learning in the world model. Values are mean ± population standard deviation over three runs. Learning in the consistency-post-trained simulator improves average real-world performance, with gains varying by task.

Real-World Testing

Selected baseline and GRPO policy rollouts. Episodes are not paired and do not estimate success rates.

Flow Matching (FM)

Test tube

Failure · The tube drops beside the tray before rack placement.
Failure · The tube is not successfully lifted and placed in the rack.
Failure · Reaches the rack, but the tube is not seated and the rack is displaced.

Bottle

Failure · The bottle is released with the cap still attached.
Failure · Repeated grasp-and-turn attempts do not separate the cap.
Success · Unscrews the cap and leaves the bottle and cap separated.

Blocks

Failure · The green bag is knocked over during placement.
Failure · The blocks are left on the table rather than inside their bags.
Success · Separates the blocks and places both into the matching bags.

ACT

Rubik's Cube

Missed grasp.
Face remains uncorrected.
Dropped before placement.

π₀.₅

Test tube

Failure · The tube is not retained upright in the rack after release.
Failure · The tube is left lying on the tabletop beside the rack.
Success · Completes the handover and leaves the tube standing in the rack.

Bottle

Failure · Turning ends without separating the cap from the bottle.
Failure · Releases the bottle before the cap has been removed.
Success · Removes the cap and places it separately from the bottle.

Blocks

Failure · The green block misses its bag and remains on the table.
Failure · Neither block reaches its bag after the separation attempt.
Success · Separates and deposits both blocks into their matching bags.

Rubik's Cube

Failure · The face turn remains incomplete when the Rubik's Cube is set down.
Failure · Releases the Rubik's Cube with a visibly offset layer.
Success · Completes the corrective face turn and sets down the aligned Rubik's Cube.

Outcomes are visually assessed; failure descriptions refer to observed behavior.