Design and Modeling of a Two-Axis Compliant Joint Based on Flexure Leaf Springs

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 com-pliant 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 con-figuration consists of four FLSs arranged in a revolute-revolute (RR) layout. Based on Euler–Bernoulli beam theory and the deformation superposition principle, linear ana-lytical 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 performance evaluation of compliant joints, which highlights its potential for practical engineering application.