Chapter 5: Active Control Systems

Active vibration damping per IEEE Control Systems Society guidelines, model-based vs adaptive control, MIMO state-space synthesis, system identification per Lennart Ljung System Identification Toolbox.

This chapter elaborates on the Active Control Systems portion of Smart Material (WIA-MAT-SMART-001). The smart material canonical envelope shape, API surface, and protocol exchanges are designed to interoperate across implementations published under the WIA Standards family. Each Phase file in `spec/` documents one architectural layer (envelopes, REST surface, federation, ecosystem) and the present chapter focuses on the active control systems subset of that layering.

Implementations of active control systems need to reconcile the per-standard expectations of IEEE 176-1987 (Standard on Piezoelectricity), ASTM F2229-19 (Smart materials data exchange), ISO 23932 (Adaptive structures), IEC 60068 series (Environmental testing), MIL-STD-810H (Environmental engineering). The Phase 1 envelope class for Smart Material carries the per-host identifier and per-tenant identifier so that audit records can be reconstructed across hosts that federate through the Phase 3 protocol layer.

Operators stepping into active control systems typically follow this trajectory: stand up the reference simulator at `simulator/index.html`, walk the canonical envelope per the CLI helper at `cli/smart-material.sh envelope`, then exercise the Phase 2 endpoints with curl/Postman against a host running the reference container at `wia/smart-material-host:1.0.0`. Once those steps complete, integrators wire the real backend one endpoint at a time per the Phase 1 §A.* envelope catalogue and the Phase 2 §B.* endpoint catalogue.

A common operational concern in the active control systems space is observability. Every Phase 1 envelope SHOULD emit a structured log line at the host's audit transport with: timestamp per RFC 3339, host identifier, tenant identifier, envelope class, envelope identifier, operation outcome, and a W3C Trace Context `traceparent` propagated end-to-end. Phase 2 surfaces this trace identifier as the `X-WIA-Trace-Id` response header. Phase 3 protocol exchanges propagate the trace identifier inside the exchange envelope so that a federation crossing remains correlatable end-to-end.

The active control systems portion of the standard composes with: WIA-OMNI-API for credential storage, WIA-AIR-SHIELD for runtime trust list, WIA-INTENT for workload intent declaration, and WIA Secure Enclave for sealed-data envelopes where personal data is processed. The composition lets one host running multiple WIA family standards reuse one identity, one signing-key chain, and one audit transport rather than maintaining N parallel per-standard implementations.