Parallel mechanisms usually have several direct kinematic solutions that are attributed to different assembly modes (AMs) or postures. The present investigation deals with AM changing, and shows that beside the known cusp points, it is possible to change AM by moving on a path like a ramp, while encircling an alpha-curve in the joint space. For micromechanisms, where clearances at the mechanism joints are relatively large, AM changing may also occur when approaching a direct kinematic singularity.

This paper introduces a new architecture of a six degrees-of-freedom parallel robot suitable for microelectromechanical systems (MEMS) fabrication. The robot consists of only revolute joints for the passive joints, and linear actuators located at the base for the active ones, both of which are easier to manufacture in MEMS technology. The hybrid kinematic structure contains three single-loop submechanisms connected in parallel to the moving platform. The solutions of the inverse and direct kinematics problems are presented

This paper deals with the difficulties that arise in the realization of micro-mechanisms by MEMS fabrication technique e.g.: fabrication of joints and actuators, joints clearance, lifting the structure from the 2D silicon wafer plane. It then introduces a new structure of a six degrees-of-freedom parallel robot that is suitable for MEMS fabrication. The robot consists of linear actuators located at the base and only revolute joints, both of which are easier to manufacture in MEMS technology. The hybrid kinematic structure contains three single loop sub-mechanisms connected in parallel to the moving platform, and the solution of its inverse kinematics which yields 4,096 solutions is presented.