Feedback control of a shape memory alloy actuator for control surface deflection

[摘要] ENGLISH ABSTRACT:The successful design, implementation and testing of a feedback control system fortab-deflection control of a shape memory alloy (SMA) based control surface actuatoris presented. The research is performed as part of the Control Surfaces in ConfinedSpaces (CoSICS) research project conducted at Stellenbosch University. The researchgroup investigates ways to provide control surface actuation in size-restricted spacesin commercial aircraft such as the Airbus A320 and A330. This is achieved by investigatingthe concept of trailing edge tabs to reduce the required torque load, resultingin reduced actuator requirements enabling the use of smaller actuators. This thesiscontributes to the project by investigating the possibility of using SMA-based actuatorsin reduced hinge moment requirement applications.An SMA-based tab actuator demonstrator design is presented. Mathematical modelsare derived for the SMA material, thermodynamics and actuator geometry. The modelsare combined to formulate an SMA-based control surface actuator model. The model isutilised in four tracking feedback controller designs; two based on linear and two basedon non-linear control techniques.The manufactured prototype is presented along with the incorporated hardware forcontroller implementation. System identification follows and validates the three mathematicalmodels.Practical verification of the model and two of the controllers is conducted. The unimplementedcontrollers are implemented through a validated model simulation. Controllerevaluation, based on the dynamic controller performance, is conducted. The resultsvalidate the concept of using an SMA actuator for tab-deflection control and indicateimportant limitations for the intended application.

[发布机构] Stellenbosch University