Research on the mechanics of bionic prosthetic fingers: objectivity in the improvement of mechanical components

Abstract

This paper examines important challenges in the mechanics of bionic prostheses, focusing on improving their functionality, reliability, and accessibility against increasing global amputation rates. This research aims to identify key mechanical components requiring development and to substantiate the advantages of implementing compliant mechanism technology in bionic finger designs. The methodology is based on functional-cost analysis using the FAST diagram approach, which systematically breaks down the functional hierarchy of finger prostheses and reveals critical relationships between various components. This analysis is complemented by a comprehensive review of recent innovations in flexible joint mechanisms for robotic and prosthetic applications. Three main functional nodes with the highest interconnectivity were identified as subjects of research: phalanges material, drive mechanism with joints, and additive manufacturing technologies. Compliant mechanisms provide significant advantages over traditional designs, replacing multiple hinged joints with integrated flexible structures. Quantitative analysis from reviewed studies shows that optimized compliant designs can provide up to 68 % greater force (5.86 N compared to 3.48 N in conventional designs), absorb 11 % more impact energy, and withstand static loads up to 26 kg while maintaining natural movement patterns with deflection angles of 45–90°. The originality of this research lies in the systematic identification of functional relationships in bionic finger mechanics and the substantiation of compliant mechanism technology as an integrative solution that simultaneously satisfies multiple functional requirements. The practical value includes the potential for significantly reducing manufacturing complexity, eliminating maintenance needs, improving durability, and enhancing adaptive gripping capabilities, which directly contribute to better user experience and prosthetic acceptance.