Universal Instruments Corporation

Steven C Bessette

Andrew Zalesski

Charles Andrew Coots

James E York

A variable reluctance linear motor has a stator and an armature mounted so as to be movable along the length of the stator. Armature bearings are mounted to the armature via mechanical vibration dampers and contact the stator so that vibrations in the stator are transmitted to the bearings and dissipated in said vibration dampers. A sensor is mounted to the armature for obtaining position data for the armature with respect to the stator. A controller then calculates the phase currents for the motor phases based on the position data and a desired force value. The phase currents are calculated to maintain a minimum normal force between the armature and said stator, thereby further reducing vibrations. A conditional filter is applied when armature is within a predetermined distance from a desired location. The conditional filter, after a time delay, clamps the velocity feedback to a predetermined range and simultaneously reduces the velocity loop gain.

Method and apparatus for vibration reduction/control in a variable

A controller for force compensation in a variable reluctance motor includes a sensor coupled to the variable reluctance motor for obtaining instantaneous motor position data and a controller coupled to the sensor for receiving the instantaneous motor position data and desired force command. The controller includes a circuit for comparing the instantaneous motor position data and the desired force command with a plurality of stored data points. Each stored data point represents a phase current value. The comparing circuit identifies a selected stored data point having position and desired force command values numerically closest to the instantaneous motor position data and the desired force command. The controller also includes a circuit for interpolating a desired phase current value based on the phase current value of the selected stored data points; a circuit for generating a current having the desired phase current values; and a circuit for outputting the current to the variable reluctance motor. A method of force compensation in a variable reluctance motor includes the steps of obtaining instantaneous motor position data for the variable reluctance motor; using a truncated value of the instantaneous motor position and desired force command to identify a selected stored data points from a plurality of stored data points; interpolating a desired phase current value based on the selected stored data; and applying a current having the desired phase current value to the variable reluctance motor. The selected data points are numerically closest to the instantaneous motor position data and the desired force command and the stored data points each represent a phase current value.

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Maine, NY, United States of America

Steven C Bessette