In the field of parallel robots, traditional rigid joints compromise motion accuracy owing to inherent friction and backlash, thus driving the demand for high-performance compliant joints. This paper proposes a parametric design method for a two-axis compliant joint that employs flexure leaf springs (FLSs) as rigid joint alternatives. The joint configuration consists of four FLSs arranged in a revolute–revolute (RR) layout. Based on Euler–Bernoulli beam theory and the deformation superposition principle, linear analytical models for the compliance and stress characteristics of both the flexure leaf spring (FLS) and the compliant joint are derived. These models are validated through finite element analysis (FEA) and rotational motion experiments. The results indicate that the relative errors between the analytical model (AM) and finite element model (FEM) are below 8%, while the relative errors between the AM and experimental data are within 12%. The proposed parametric design method enables rapid preliminary design and the performance evaluation of the two-axis compliant joint, which is intended as a rotational joint for six degrees of freedom (6-DOF) parallel robots with typical applications in high-precision optical alignment.
Feng et al. (Tue,) studied this question.