Singularity analysis of parallel manipulators using constraint plane method

One of the most challenging problems in dealing with parallel manipulators is identifying their forward singular configurations. In such configurations these mechanisms become uncontrollable and cannot tolerate any external force. In this article a geometrical method, namely Constraint Plane Method (CPM), is introduced with the use of which one can easily obtain the singular configurations in many parallel manipulators. CPM is a methodical technique based on the famous Ceva plane geometry theorem. It is interesting to note that CPM involves no calculations and yields te result quickly. In addition, some of the previous geometrical methods led to many separate singular configurations; however, CPM yields the answer in just one phrase. In this article we have obtained singular configurations of some parallel manipulators. Moreover, a comparison is made between CPM and the previous methods to show the advantages of CPM.