Abstract: As the distributed fully-compliant mechanism contains no rigid components and kinematic-pairs, the conversion between its motion and energy is realized by the deformation of compliant components, so it has the advantages of simple construction, less mass and no joint clearance. The pseudo-rigid-body modeling method for this kind of mechanism is investigated by taking J-type energy storing foot as an example. To enhance the model precision, the compliant mechanism is equalized to the elastically articulated multi-rigid-body system, the curvature principle and stiffness principle for pseudo-rigid-segments partition are proposed on the basis of geometrical shape and stiffness distribution of compliant components, and the modified formula for calculating torsional spring constants of equivalent joints is developed. The formula for calculating deformations of a multi-rigid-body system is also given on the basis of influence coefficient theory. By comparing with the corresponding results from finite element analysis, the influence of partition methods, partition number and torsional spring constants on the model precision is investigated. The results show that the partition method based on geometrical shape and stiffness distribution is effective. The appropriate segment number of the J-type energy-storing foot and the correction coefficients of torsional spring constants are obtained. The presented modeling method can be further applied to the design and analysis of the distributed fully-compliant mechanisms with closed loops.

Key words: Distributed fully-compliant mechanism, Energy-storing foot, Pseudo-rigid-body modeling, Pseudo-rigid-segment partition