Waters Technologies Corporation

Kevin Alstrin

David Louis Dingmann

Charles Groepper

Nicholas Fruge

Sudarshan Betigeri

A linear motor including a stator assembly, an armature mechanically coupleable to a test specimen configured to be moved relative to the stator assembly by operation of the linear motor, and a suspension system configured facilitate movement of the armature relative to the stator assembly along an axis of movement without physically touching the armature during movement. Further disclosed is a multi-phase linear motor, a linear motor having an armature with an array of flat magnets, and a linear motor having a magnetic damping system.

Linear motor

An actuator control system, mechanical testing system, and method for adaptive control of an actuator of a mechanical testing device is provided. The method includes applying a mechanical load to the specimen with the actuator, resulting in receiving a load sensor signal from a load sensor and a displacement sensor signal from a displacement sensor, deriving lumped dynamics of the mechanical testing device by analyzing a phase and magnitude relationship between a current command of a motor of the mechanical testing device and a resultant deflection of the specimen, and controlling the actuator based on the derived lumped dynamics of the mechanical testing device such that the controlling results in a stable motion.

Determination of dynamic parameters for adaptive actuator control

An actuator control system, mechanical testing system, and method for adaptive control of an actuator of a mechanical testing device is provided. The method may include applying a mechanical load to the specimen with the actuator, resulting in receiving a load sensor signal from a load sensor and a displacement sensor signal from a displacement sensor, determining a plurality of dynamic characteristics of the mechanical testing device throughout a length of the test from data received from the load sensor signal and the displacement sensor signal, and controlling the actuator based on the plurality of dynamic characteristics to adapt the actuator to track a desired performance of the actuator.

An actuator control system, mechanical testing system, and method for adaptive control of an actuator of a mechanical testing device may include determining a stiffness of a medium that the actuator is moving through and/or load gain of the actuator, wherein the stiffness and load gain is determined by generating a waveform to actuate the actuator until a load sensor signal and/or a displacement sensor signal is received, and controllably moving the actuator through the medium according to a predefined constant velocity by calculating a current request using the stiffness of the medium, and/or adjusting the load of the actuator in accordance with a constant load ramp rate.

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Excelsior, MN, United States of America

Kevin Alstrin