Design and analysis of planar rotary springs

This paper is concerned with the analysis, design, and prototyping of rotary planar springs for robotics applications such as rotary series elastic actuators, or mechanical couplings. The key contribution is the development of a mathematical model, based on curved beam theory, that allows rapid design, analysis, and optimization of rotary springs that have arbitrary arm shape. The paper also introduces methods to reduce the spring mass via composite arm structures, or arm cutouts. A prototype is designed, analyzed and tested to demonstrate the validity of the model.