Limited-angle Torque Motor Research Articles

Performance evaluation for a limited-angle torque motor

Describes the performance evaluation of a limited-angle torque motor, using a simple piecewise analytical approach to overcome system nonlinearities. A block-diagram model developed from a combination of measurement and manufacturer's data is shown to be capable of accurately predicting both the steady-state and the dynamic performance. The approach described is of valuable assistance in the design of a complex multiloop nonlinear controller that is needed for a drive system containing the motor.

Investigation of the effects of design parameters on output characteristics of capacitive angular displacement sensors by finite element field modelling

The effects of design parameters on performance characteristics of a capacitive angular displacement sensor used in limited angle torque motors are investigated. This is done by 2D finite element modelling and computation of electrostatic fields in the complex geometry of the sensor. Results are presented in terms of sensor's output characteristic showing the effects of some of its material and geometric parameters. The output characteristic investigated is the variation of sensor output voltage V with angular position /spl theta/ of the motor rotor, V=f(/spl theta/). The design parameters used comprise permittivities of various dielectric materials and angular width w/sub 1/ of the sensor.

Modern dynamo electric machinery

This paper presents techniques for design and control of a brushless direct-current (DC) limited-angle torque motor (LATM) with its application to fuel control of gas turbine engines. Given the desired specifications, a two-pole brushless DC LATM with a toroidally wound armature is designed using selected ferromagnetic material and rare-earth permanent magnets; its electromagnetic characteristics is then computationally found and well tuned using the finite element method (FEM) in order to ensure whether the design meets the performance specifications. To achieve the simple and inexpensive semi-closed-loop fuel control, a robust position controller (including a proportional-integral-derivative (PID) controller with a prefilter) is synthesized for providing the required positioning performance for the developed motor, thereby achieving an inexpensive semi-closed-loop fuel control. A closed-loop fuel controller associated with the proposed position controller and a flow meter is then proposed based on multi-loop control structure in order to achieve required linear input–output relationship. All the proposed fuel control laws were implemented using a stand-alone single-chip digital signal processor (DSP). Experimental results are conducted to show the efficacy and usefulness of the developed limited-angle torque motor with its application to an experimental gas turbine fuel control test platform.