Author: Street A. Barnett

Publisher:

Published: 2015

Total Pages: 99

ISBN-13:

A laboratory apparatus and data acquisition system were constructed for evaluating aircraft flight control actuators under simulated mission profiles. A MTS hydraulic load frame was used to simulate a control surface's aero load. A NI based DAQ system was used to record the motor controller's DC bus voltage at a high rate, actuator's position, load, and temperatures. The DC bus rms voltage, current, and power, and regenerative power were recorded by a Newton's 4th power analyzer. Key performance characteristics tests such as frequency response, step response, reversal, backlash, and holding with a Danahar EC5 actuator were carried out to verify this laboratory setup.The continuous frequency sweeping test revealed that the EMA reached the speed limit first, then the current limit, and finally the temperature limit. When the actuator's electronics reached the thermal limit, the actuator controller drastically reduced its power. This caused drastic magnitude attenuation and phase lagging. Continuous frequency sweeping proved to be a useful test to evaluate the EMA's characteristics. The lab tests showed that holding presents the most significant challenge to the thermal management of an EMA system. To reduce the thermal gradient within the motor, a half rotation back forth at 0.01 Hz sinusoidal disturbance was imposed during holding to evenly engage the motor's three phases. This resulted in an 81% temperature variation reduction among the three windings. Although this small motion disturbance is effective in reducing the motor and motor drive's thermal gradient, it is not known if such a disturbance is feasible in practice.The step response and reversal test showed that when an EMA reverses direction or suddenly decelerates, a significant spike of regenerative power occurred. This regenerative power could present itself as a thermal challenge to an aircraft flight control EMA system.Using the MTS hydraulic load frame to simulate a dynamic aero load of a flight control surface in synchronization with position movement of an actuator proved to be a challenge. A double loop control scheme has been derived which compensates the time delay difference between the load frame and the actuator. It is our hope that this control strategy, once fully implemented, will enable more accurate dynamic load control in simulating an EMA's mission profile for performance evaluation.