Stiffness mapping of compliant parallel mechanisms in a serial arrangement

This paper presents a stiffness mapping of a mechanism having two compliant parallel mechanisms in a serial arrangement. A derivative of the wrench connecting two moving bodies is derived and applied to obtain the stiffness matrix of the mechanism. It is shown that the resultant compliance of two compliant parallel mechanisms that are serially arranged is not the summation of the compliances of the constituent mechanisms unless the external wrench applied to the mechanism is zero. A numerical example is presented to support the result.