A Load-Bearing, Fluid-Mediated Robotic Joint Architecture Combining Variable-Geometry Friction Interlocks with Passive Multi-Stage Granular Jamming Inside a Tensegrity Compression Frame

This paper describes the QUINTO-CMC modular articulation architecture, built to hold high structural loads in contaminated or corrosive operating environments while cutting static holding power to a minimal telemetry-only draw. The system replaces high-maintenance, actively powered joints with an unpowered, field-replaceable cartridge that locks mechanically under zero electrical load. The physical joint module weighs no more than 1.75 kg. Static holding draw is limited to 18–25 W for telemetry and monitoring alone — the mechanical lock itself needs no electrical power. Three kinematically uncoupled passive locking layers trigger in sequence during pressure drops or sudden fluid loss. The primary retention tier uses a 4.5° self-locking mechanical wedge gate, where laser-etched micro-surfaces hold an operational friction coefficient of at least 0.11 nominal (0.095 as a conservative end-of-life floor) when submerged in a colloidal magnetic nanoparticle medium. The auxiliary tier deploys a granular particle-jamming core that triggers when system pressure drops below 3.0 MPa, giving an unpowered structural lock that stays disengaged through normal transient pressure dips down to 2.1 MPa. A radial friction stop forms the final safety boundary, limiting structural backlash to 0.5°. Hydraulic fluid routing runs through the internal hollow passages of the rigid compression struts in a structural tensegrity frame, keeping the high-pressure working fluid circuits fully separated from the dry tension network. This document records these mechanism combinations as prior art, protecting the disclosed technical baseline from third-party patent claims.