On the mobility and configuration singularity of mechanisms with variable topologies

The mechanisms with variable topologies (MVTs) are usually changing their topological structures in accordance with the varying mobility and quasi-singular configurations. The mobility analysis and configuration singularity of MVTs are studied via screw theory in this paper. The configurations of MVTs are formulated by a set of variable combinations of screw coordinates. For the mobility analysis, two examples provided show that the proposed approach is adoptable for dealing with common MVTs. For the configuration singularity, the concepts of stationary configuration and uncertainty configuration are utilized to demonstrate the topology varying strategy of MVTs. The result in this work provides the theoretical basis and inspiration for the configuration synthesis and analysis of mechanisms with variable topologies.