Design of general kinematotropic mechanisms

•A systematic design method of general kinematotropic mechanisms is presented.•Basic structures of spatial motions in serial and parallel forms are synthesized.•Basic kinematotropic design principles and rules are presented.•Four kinematotropic mechanisms are synthesized and analyzed as examples.

The general mobility of a linkage mechanism is determined during its continuous motions, but there is a class of mechanisms with kinematotropic properties whose mobility can be changed at singularities of their pose, while their kinematic structure remains unchanged in the different motion modes. This paper presents a systematic design method for general kinematotropic mechanisms. Firstly, the basic kinematic structures of spatial motions in serial and parallel forms are introduced. Secondly, the basic properties and design rules of kinematotropic mechanisms are defined, and the basic serial kinematic chains with variable constraint relations are presented. Thirdly, a systematic method for kinematic structural synthesis of general kinematotropic mechanisms is proposed. Finally, two types of motion transformations with four kinematotropic mechanisms are synthesized and analyzed as illustrative examples of the method.