Research on the line-arc-line constant-torque flexure hinge (LAL-CTFH) based on improved pseudo-rigid-body model (PRBM)

• Published in: Mechanism and machine theory 2022-08, Vol.174, p.104878, Article 104878
• Main Authors: Qiu, Lifang, Li, Chongxiang, Dai, Shenyuan, Yu, Yue
• Format: Article
• Language: English
• Subjects: Constant-torque mechanism; Flexure hinge; Line-arc-line segment; Optimization; Pseudo-rigid-body model (PRBM)
• ISSN: 0094-114X; 1873-3999
• DOI: 10.1016/j.mechmachtheory.2022.104878

•A constant-torque flexure hinge based on line-arc-line segment (LAL-CTFH) is designed.•An improved PRBM method called FB-PRBM for the LAL-CTFH is proposed.•Theoretical analysis, FEA and experimental test of LAL-CTFH are carried out for verification.•The constant-torque output proportion of LAL-CTFH is more than 65%. In order to enlarge the proportion of constant-torque output, a new type of constant-torque flexure hinge based on line-arc-line segment (LAL-CTFH) is designed. The LAL-CTFH has the characteristics of good constant-torque output performance, simple structure and easy manufacturing. The improved pseudo-rigid-body model (PRBM) method named four-bar linkage PRBM (FB-PRBM) for the LAL-CTFH is proposed to analyze the torque-angle characteristics of LAL-CTFH. The method is verified by finite element analysis (FEA). Furthermore, the constant-torque output characteristics of LAL-CTFH are optimized. Theoretical analysis, FEA, physical prototype production and experimental test of the optimized model are carried out respectively. The results show that in the range of 0–40°, the proportion of constant-torque output can reach more than 65%, the error between theoretical value and FEA value is less than 1%, and the average error between theoretical value and test value is less than 5%, which verifies the feasibility of the design scheme and the validity of the theoretical analysis. [Display omitted]