# Synthetic-generation methodology

The repository uses deterministic surrogate equations to produce reproducible signals with the same dimensional structure expected from an OpenSim-centered upper-limb exoskeleton workflow.

- Cycle duration: 6.0 s
- Sampling rate: 50 Hz
- Samples per cycle: 300
- Random seed: 7026226

A smooth overhead-work envelope is defined as `0.5*(1-cos(2*pi*t/T))`. Shoulder elevation, trunk flexion, baseline shoulder moment, device assistance, muscle-activation surrogates, and interface forces are generated from this envelope, scenario load, virtual-model scaling, and small seeded perturbations. Interface normal force depends on base preload, assistance torque transfer, movement envelope, and interface-specific gains. Tangential force is a signed fraction of normal force with interface-specific phase offset. Estimated mean pressure equals normal force divided by the declared effective contact area.

The 45 N threshold is used only to compute time-above-threshold and high-load peak counts in this synthetic demonstration. It has no clinical, physiological, or injury interpretation.