Apparatus for controlling linear motors

Abstract From the Canadian patent

A reciprocatable shuttle employed to advance a variable number of article carriers through successive work stations is driven on forward and return movements by a plurality of energizable linear motor stators for which the shuttle forms a common reactor. Energization of the stators is controlled by a programmable logic controller in response to inputs from velocity measuring circuits which determine the difference in the actual velocity of the shuttle relative to a desired maximum forward velocity return velocity, and creep velocity; to inputs from distance measuring circuits which determine the distance travelled by the shuttle relative to a forward deceleration point and to a return …