Analysis on coupling effect of 2-DOF direct drive induction motor based on 3-D model

Two degrees of freedom (2-DOF) direct-drive induction motor capable of producing pure rotary motion, pure linear motion, or helical motion can be applied in some special occasions. The complex structure and multi-form motion of 2-DOF direct-drive induction motor made it difficult to analyze the characteristics. This paper analyzed the 2-DOF motor from the perspective of single DOF motor and converted cylindrical coordinate system to Cartesian coordinate system adopting the simplified equivalent plate model. Analytic models of two-dimensional (2-D) electromagnetic field for end-effect and 3-D motion coupling effect in the motor were established using Maxwell´s equations respectively. Three-dimensional (3-D) finite element model of 2-DOF direct drive induction motor was established for taking account of the influence of motion coupling, magnetic field coupling and end-effect more accurately. The motor performances in different operation state were simulated and the rationality and feasibility of the proposed motor as well as the existence of electromagnetic coupling and motion coupling effect was verified.