Configurations and mathematical models of parallel link mechanisms using multi drive linear motors

In this paper, parallel link mechanisms for multi drive linear motors (MDLMs) are proposed. The multi drive is a control method for linear motors in which a number of moving parts are individually driven on one stator part. Various configurations of parallel link mechanisms which were constructed for MDLMs are proposed. These mechanisms offer a wide range of motion in addition to the existing characteristics that parallel mechanisms provide, namely, rigid mechanisms, high precision, and high speed. Moreover, they are suitable for force control because of their low friction direct drive actuators. In this paper, the kinematic and dynamic characteristics of 2-DOF (xy) and 3-DOF (xy¿) planar parallel link mechanisms are investigated. A singularity analysis and internal force control method for a 3-DOF with 4 redundant moving parts is derived. The condition of dynamic decoupling and the constant inertia design of a 2-DOF with 2 moving parts and a 3-DOF with 4 moving parts are derived. The effectiveness of these analyses is then confirmed by numerical simulation. Based on this analysis, a prototype of the 3-DOF with 4 moving parts is designed and developed.