Cogging force analysis of linear motor arrays driving the Thirty Meter Telescope

A finite element analysis of the cogging force generated by an array of linear synchronous motors moving on a curvilinear track is presented. This system is under consideration as the driving system for the two main axes of the Thirty Meter Telescope that will be built in Mauna Kea, Hawaii. The main objective of this work is the quantification of the effects of the curvilinear track on the motors cogging force. The finite element analysis is carried out using planar cross sections, and the results found are used to find an approximate solution for the three-dimensional model. The results show that the presence of the curvilinear-configured track significantly increases the cogging force of a single motor, while the presence of several motors interacts in limiting the increase in the cogging force. Finally, in order to reduce the total cogging force, an optimization in regards to the relative positions of the motors along the tracks is carried out.