Non-dimensional approach for static balancing of rotational flexures

• We introduce a non-dimensional method for statically balancing compliant mechanisms.
• Methods are developed for idealized and load-dependent systems.
• A physical prototype of a load-dependent cross-axis-flexural pivot is designed and tested.
• An average stiffness reduction of 87% is demonstrated over an 80 degree deflection range.

This work presents a general method of statically balancing flexural hinges. Using a set of non-dimensional parameters, we show that one can quickly design a statically balanced rotational flexure. First, a balancing method is developed for an idealized hinge/torsion spring system. This method is then extended to load-dependent systems and is demonstrated with the design of a balanced cross-axis-flexural pivot with stiffness that varies as a function of compressive preload. A physical prototype is built and tested to verify the design method. This method is general for any system that has a well understood stiffness response to an applied compressive load.