Daniel Grant

Flight Dynamics of a Morphing Aircraft Utilizing Independent Multiple-Joint Wing Sweep:

Morphing, which changes the shape and configuration of an aircraft, is being adopted to expand mission capabilities of aircraft. The introduction of biologically-inspired morphing is particularly attractive in that highly-agile birds present examples of aerodynamically-effective shapes. This paper introduces an aircraft with a multiple-joint design that allows variations in sweep to mimic some shapes observed in birds. These variations are independent on the left and right wings along with on the inboard and outboard sections. The aircraft is designed and analyzed to demonstrate the range of flight dynamics which result from the morphing. In particular, the vehicle is shown to have enhanced turning capabilities and crosswind rejection which are certainly critical metrics for the urban environments in which these aircraft are anticipated to operate.

Time-varying dynamics of a micro air vehicle with variable-sweep morphing

In this paper, we investigate the dynamics of a rapidly morphing, variable wing sweep micro air vehicle. The time scales over which the morphing occurs are of the same order as those of the flight dynamics of the MAV. We investigate the time-varying poles and zeros of this MAV for different morphing trajectories. There are several existing notions of timevarying poles and zeros of a linear time-varying system, each with its relative advantages and disadvantages. We explore the use of two of these notions in the study of the timevarying dynamics of the MAV in both the longitudinal as well as the lateral-directional axes.

Effects of Time-Varying Inertias on Flight Dynamics of an Asymmetric Variable-Sweep Morphing Aircraft

Mission capability can be enabled by morphing an aircraft to optimize its aerodynamics and associated flight dynamics for each maneuver. Such optimization often consider the steady-state behavior of the configuration; however, the transient behavior must also be analyzed. In particular, the time-varying inertias have an effect on the flight dynamics that can adversely affect mission performance if not properly compensated. These inertia terms cause coupling between the longitudinal and lateral-directional dynamics even for maneuvers around trim. A simulation of a variable-sweep aircraft undergoing a symmetric morphing for an altitude change shows a noticeable lateral translation in the flight path because of the induced asymmetry.

Design and analysis of biomimetic joints for morphing of micro air vehicles

Flight capability for micro air vehicles is rapidly maturing throughout the aviation community; however, mission capability has not yet matured at the same pace. Maintaining trim during a descent or in the presence of crosswinds remains challenging for fixed-wing aircraft but yet is routinely performed by birds. This paper presents an overview of designs that incorporate morphing to enhance their flight characteristics. In particular, a series of joints and structures is adopted from seagulls to alter either the dihedral or sweep of the wings and thus alter the flight characteristics. The resulting vehicles are able to trim with significantly increased angles of attack and sideslip compared to traditional fixed-wing vehicles.

Optimal Tracking of Time-Varying Modes For Control of Morphing Aircraft

Morphing vehicles have inherently time-varying dynamics due to the alteration of their configurations; consequently, the numerous techniques for analysis and control of timeinvariant systems are inappropriate. A control scheme is introduced that directly considers a concept of time-varying pole to command morphing. The resulting trajectory minimizing tracking error for either a state response or a pole response.