Design and Control of a Proof-of-Concept Active Jet Engine Intake using Shape Memory Alloy Actuators

Gangbing Song*  and    Ning Ma

Department of Mechanical Engineering

University of Houston

Houston, Texas

 

Nick Penney

Ohio Aerospace Institute (OAI)

Cleveland, Ohio

 

Todd Barr

Jackson & Tull Aerospace Division

Cleveland, Ohio

 

Ho-Jun Lee and Steve Arnold

NASA Glenn Research Center

Cleveland, Ohio

ABSTRACT

It has been shown in the literature that active adjustment of the intake area of a jet engine has potential to improve its fuel efficiency. This paper presents the design and control of a novel proof-of-concept active jet engine intake using Nickel-Titanium (Ni-Ti or Nitinol) shape memory alloy (SMA) wire actuators. The Nitinol SMA material is used in this research due to its advantages such as high power-to-weight ratio and electrical resistive actuation. Nitinol SMA material can be fabricated into a variety of shapes such as strips, foils, rods and wires. In this paper, SMA wires are used due to its ability to generate a large strain: up to 6% for repeated operations. The proposed proof-of-concept engine intake employs overlapping leaves in a concentric configuration. Each leaf is mounted on a supporting bar which can rotate. The supporting bars can be actuated by an SMA wire actuator in a ring configuration. Electrical resistive heating is used to actuate the SMA wire actuator and rotate the supporting bars. To enable feedback control, a laser range sensor is used to detect the movement of a leaf and therefore the radius of the intake area. Due to the hysteresis, an inherent nonlinear phenomenon associated with SMAs, a nonlinear robust controller is used to control the SMA actuators. The control design uses the sliding-mode approach and can compensate the nonlinearities associated with the SMA actuator. A proof-of-concept model has been fabricated and its feedback control experiments show that the intake area can be precisely controlled using the SMA wire actuator and has the ability to reduce the area up to 25%. The experiments demonstrate the feasibility of engine intake area control using the proposed design.