Guidance and Control Systems
Guidance and control projects include:
The AEC Guidance and Control (G&C) Group has six faculty members and one research engineer. covering diverse areas in guidance and control (J. Zhu, T. Adami, D. Lawrence, J. Mitchell, D. Irwin), flight mechanics (R. Williams) and discrete event systems (R. Judd, W. Zhang). Together with the navigation competencies in the AEC, they form a synergy in autonomous and fault-tolerant flight management systems that integrate guidance, navigation and control with integrated vehicle health management systems (IVHM).
Facilities and Tools
AEC has two flight control test beds: a 3-DOF (VTOL) differential-thrust flight control test bed and a 6-DOF thrust-attitude control test bed. The attitude change of the 3-DOF test bed is effected by differential thrust in roll and pitch, and differential reactive torque in yaw, which exhibit significant nonlinearity and coupling. Two video clips are attached to demonstrate successful control algorithm development and the capability of the test bed. The 6-DOF test bed features a 6-DOF load cell that measures the forces and moments on the test article, a hot-wire anemometer that measure flow speed and mass flow rate, and a 48-port Scanivalve pressure sensor that measure pressure distribution on a lifting surface at 48 locations. It accommodates test articles with wingspan up to 6 feet with electrical propeller or duct fan engines. This facility can be used to study thrust and airframe interactions, and demonstrate the effectiveness of advanced control techniques. This test bed will be mounted on a moving vehicle to enable affordable near-flight condition testing of thrust and aerodynamic control effectors and control algorithms. Control algorithms and flight software validated with these test beds can be further validated with AEC’s research aircraft.
In June 2001, NASA awarded a $4.4M, 4.25-year contract to AEC under the NRA8-30 2nd Generation Reusable Launch Vehicle (2G RLV) Program to develop an Integrated Guidance and Control (IG&C) system in support of all RLV architecture concepts, which is the only G&C contract awarded in that program. The IG&C technology includes advanced adaptive, re-configurable and fault-tolerant guidance and control for trans-atmospheric ascent (powered) and entry (unpowered) flights, and an autonomous flight manager called Autocommander that integrates the IVHM system with the G&C system to autonomously execute nominal flight and cope with abnormal flight conditions with adaptation, reconfiguration and various abort modes in response to escalating anomalies. The IG&C/Autocommander technology is characterized by its crosscutting capability and an open, modular architecture, which allow the system to be quickly adapted for different vehicle architecture and expended and upgraded with the vehicle development and operation. The AEC subsequently negotiated a $5M contract with NASA for Autocommander technology gap elimination. Although both contracts were prematurely terminated as NASA restructured the NRA8-30 Program, the various components of the IG&C/Autocommander technology were successfully matured to TRL 3+ to TRL 4. Due to the nature of RLV flight, the IG&C/Autocommander technology is readily adapted for aircraft operations. After the NRA8-30 Program transitioned to the Orbital Space Plane (OSP), AEC was subcontracted by Lockheed Martin to develop fault-tolerant flight control system for it’s OSP. When the OSP program was terminated by NASA and the new Exploration Program initiated in 2004, AEC was invited to participate in a $32M Boeing proposal for developing an autonomous planetary landing vehicle for the H&RT program, which was selected for funding. The AEC’s role in this project was to develop the fault adaptive flight executive based on the Autocommander technology. This program was terminated prematurely by NASA soon after due to restructuring of the Space Program and fiscal uncertainty.