A general method to determine compatible orientation workspaces for different types of 6-DOF parallel manipulators

•Analytical methods to develop a compatible reachable workspace are presented.•The methods take account of the effect of the passive joint limits, the link interactions and singularity.•The equations for the entire workspace can be easily determined.•The characteristics of workspace boundaries are studied.

This paper presents a general method to develop a compatible orientation workspace for a 6-DOF parallel manipulator. The workspace boundary for any type of manipulator can be determined using the proposed method, if the equations for inverse kinematics can be developed. The workspace boundary can be developed by solving the equations, but the results show that a search technique that uses the bisection method is more efficient, if the equations are 4th or higher degree polynomials. In general, a workspace can be developed in less than 5 min, using a personal computer. The effect of the size of the platform, the passive joint limits, the link interactions and singularity on the shape and size of a workspace are also determined.