Investigation of Special Positions of the Parallel Mechanism of the Delta Family with Four Degrees of Freedom

The results of investigation of two types of special positions of parallel mechanism with four degrees of freedom and four linear drives are presented. To solve the problem, an iterative algorithm is used, which consists in a linear exhaustive search of the points of the working zone of the mechanism and analysis of the behavior of the determinants of the matrices of partial derivatives of the input and output coordinates. The solution of the problem stated is necessary to estimate the dimensions of the effective working zone of the mechanism and is an important stage in its parametric synthesis and design.