Human Motion Foundation Model

KAIST Exoskeleton Lab

Human Motion Foundation Model

Understanding Human Motion from Sparse Observations

Detailed movement analysis often relies on motion capture systems and force measurements in a laboratory. Wearable sensors allow repeated measurements in everyday settings, but provide only a partial view of the body's motion and forces.

The Human Motion Foundation Model aims to recover full-body movement and biomechanical loading from limited wearable measurements. Paired wearable and laboratory recordings provide the basis for learning how signals from motion sensors and pressure insoles relate to whole-body movement.

Our research combines wearable sensing, biomechanics, machine learning and physics simulation.

Inputs

  • Motion signals
  • Insole pressure
  • Context & masks
Motion signals, insole pressure and context enter a sequence model that outputs body motion, foot forces and moments, and uncertainty. Human Movement Model

Outputs

  • Body motion
  • Foot forces & moments
  • Uncertainty

Toward Human Movement Understanding and Wearable Assistance

Paired wearable and laboratory recordings provide the foundation for developing the Human Motion Foundation Model. Data collection across multiple sites, supported by refinement and quality checks, is intended to capture a wider range of people and movement conditions. Synthetic IMU signals will complement measured recordings.

The resulting model is intended to support human movement research and wearable assistance by connecting wearable measurements with full-body motion and force estimates. These outputs provide a basis for applications that account for how people move.

Person wearing IMUs, a sensor vest and pressure insoles, seen from the front, side and back.

Wearable sensors

Movement and pressure measurements

Recordings funnelled through quality checks into a clean, structured dataset.

Training data

Paired wearable and laboratory recordings

A neural network maps a sparsely instrumented walker to a full-body motion estimate.

Human Motion Foundation Model

Movement and force estimates

Person walking with a lower-limb wearable assistance device.

Applications

Movement research and wearable assistance

Leg motion converted into simulated accelerometer and gyroscope signals.

Synthetic data generation

Simulated wearable signals add to the training data.

The multi-site data behind the model follows the lab's Exo-Data Standard.

Combining Physics and Neural Models for IMU Synthesis

Synthetic IMU generation converts recorded human motion into acceleration and gyroscope signals. Motion-capture recordings provide the basis for physics-based signal calculation. Neural models then refine these signals to better match real IMU recordings.

This approach combines physics-based signal generation with learning from measured data. The generated signals are intended to complement recorded IMU data and support training of the Human Motion Foundation Model to recover full-body movement and biomechanical loading from sparse wearable measurements.

IMU synthesis: optical marker recordings feed physics-based IMU synthesis, which produces initial acceleration and gyroscope signals; neural signal refinement, trained against recorded IMUs, outputs refined synthetic IMUs used by motion estimation models to recover full-body motion and joint kinematics.

Physics-Based Motion Generation

The proposed approach uses a motion generator to provide a reference trajectory. An imitation policy learns to control a simulated body to follow that trajectory inside a physics simulator. Contact with the ground, gravity and joint limits constrain how the body moves.

This connects generated motion with physically plausible execution. Alongside the resulting movement, the simulator provides estimates of ground-reaction forces, joint moments and power. These outputs allow researchers to examine both how the body moves and the mechanical demands involved in performing the movement.

Movement representation

Motion features + other details

Motion Generator

Generated body motion

INSIDE A PHYSICS SIMULATOR

Imitation Learning Policy

Tracks the reference

Plausible Motion

Motion and forces

WALK

Reference motion
Imitated motion

KICK

Reference motion
Imitated motion

JUMP

Reference motion
Imitated motion

SQUAT

Reference motion
Imitated motion