Physics-Based Communication Compression via Lyapunov-Weighted Event-Triggered Control

Event-Triggered Control (ETC) reduces communication overhead in networked systems by transmitting only when stability requires it. Conventional mechanisms use isotropic error thresholds ($\|e\| \le \sigma \|x\|$), treating all directions equally. This ignores stability geometry and triggers conservatively. We propose a static directional triggering mechanism that exploits this asymmetry. By weighting errors via the Lyapunov matrix $P$, we define an anisotropic half-space scaling with instantaneous energy margins: larger deviations tolerated along stable modes, strict bounds where instability threatens. We prove global asymptotic stability and exclusion of Zeno behavior. Monte Carlo simulations ($N=100$) show 43.6\% fewer events than optimally tuned isotropic methods while achieving $2.1\times$ better control performance than time-varying alternatives. The mechanism functions as a runtime safety gate for learning-based controllers operating under communication constraints.