Application Status of Engineering Materials in Humanoid Robot Bodies and a Preliminary Exploration of Systematic Material Selection Methodology

Humanoid robots are transitioning from laboratory prototypes to industrial mass production, with body material selection directly affecting locomotion performance, energy consumption, and manufacturing cost. Current representative products have adopted combinations of carbon fiber composites, polyetheretherketone (PEEK), aluminum alloys, and magnesium alloys. However, material selection largely relies on engineering experience and industry conventions, lacking a systematic methodology that accounts for multi-component coupling characteristics. The application status of metallic, polymeric, and composite materials in humanoid robot bodies is reviewed, and existing methodologies including the Ashby material selection approach and multi-criteria decision making (MCDM) methods are examined, identifying two fundamental limitations: the single-component assumption and combinatorial explosion. On this basis, a three-tier selection framework of “component-level constraint screening → system-level coupling optimization → supply-chain scenario assessment” is proposed. Using the NimbRo-OP2X open platform as a case study with parameterized verification covering 12 components and 16 candidate materials, the framework is shown to effectively balance mass, cost, and manufacturability, providing a structured decision-support pathway for material selection in production-oriented humanoid robots.