Cyclic Movable Cultivation Rack with TIR-Based Supplemental Lighting for Hydroponic Barley Fodder

Improving space use while reducing supplemental-lighting demand is important for compact hydroponic fodder production. We developed a cyclic movable cultivation rack with total internal reflection (TIR)-based supplemental lighting and evaluated its geometry, preliminary structural performance, device-level light distribution, and short-cycle crop response. Relative to a predefined double-sided static geometric reference, the cyclic configuration increased nominal tray cultivation area by 36.4%. A preliminary linear-static check under a 5850 N equivalent load gave a maximum von Mises stress of 108.8 MPa, maximum deformation of 3.307 mm, and a yield-based safety factor of 2.16 for Q235 steel. At comparable recorded input power, TIR increased mean PPFD by 93.1% within the prescribed 350 mm single-unit reference-plane grid. After calibration to reference-plane mean-PPFD equivalence, lighting-unit AC active power decreased from 25.41 to 13.10 W, a descriptive 48.4% reduction relative to the same lens-free WS2812-based prototype baseline. In cultivation, harvested fresh biomass differed by approximately 0.3%, and the retrospective one-sided confidence bound was compatible with an exploratory 5% engineering margin but not the stricter 2% sensitivity margin. The results support prototype feasibility while array-level canopy photon exposure, whole-facility energy performance, and long-term mechanical reliability require further validation.