Fig. 2From: An analysis of usability evaluation practices and contexts of use in wearable roboticsTechnology Maturity of Current Wearable Robotic Devices: The Technology Readiness Levels (TRL) of the four general usage purposes, visualized as stacked histogram (n = 143). The TRL were grouped in three Technology Readiness Phases (TRP): “Concept” (TRL 1–3), “Prototype” (TRL 4–7) and “Product” (TRL 8–9)Back to article page