Abstract: For the sake of improving the properties of parallel mechanisms, the application of compliant bi-stable mechanism for overcoming the singularity of kinematics and force manipu-lation of parallel mechanism are investigated. A kind of cam compliant mechanism with bi-stable property is proposed. The bi-stable compliant cam mechanism can provide nonzero inter-nal force in unstable configuration for a parallel mechanism, thus the nonzero internal force can be used to remove the un-certainty of motion or manipulation force. As an example, a planar five bars 2-DOF parallel mechanism is discussed, the working space is drawn and the motion and force manipulation singularity are analyzed. The simulation and calculation results show that the bi-stable compliant cam mechanism can control the planar five bars 2-DOF parallel mechanism at the singular-ity configuration.

Key words: Bi-stable mechanism, Force singularity, Kinematics singularity, Parallel mechanism