• Dr. Ratneshwar Jha
  • Clarkson University
  • 1060 Torgersen Hall
  • 10:05 a.m.

This presentation will focus on the technologies of smart structures and adaptive systems with applications to aircraft design. Smart structures technology has the potential to significantly impact numerous products in diverse industries such as aerospace, wind energy, and civil infrastructure. Recent research in the Smart Structures Laboratory at Clarkson University will be presented with particular emphasis on Lamb wave based health monitoring of aerospace composite structures. This research involves the development of damage detection algorithms through an understanding of structural mechanics, elastic wave propagation, and advanced signal processing. The use of wavelet based spectral finite elements (FE in frequency domain) for wave propagation in composite plates will be discussed. An overview of vibration based damage detection using proper orthogonal decomposition and Hilbert-Huang transform will be presented.

 

Adaptive control systems can maintain consistent performance of a system in the presence of uncertainty or unknown variation in plant parameters. A hybrid adaptive control scheme is designed as a launch vehicle flight controller for ascent phase of NASA Crew Launch Vehicle. The hybrid adaptive control approach augments linear feedback signals with contributions from both direct and indirect adaptive control elements. In addition, signal filters are incorporated into the feedback loop to prevent harmful interaction between the flight control system and structural bending modes. The performance of the hybrid adaptive flight controller is compared to that of a typical gain-scheduled linear feedback controller in a high-fidelity Ares I ascent simulator obtained from the NASA Marshall Space Flight Center. The hybrid controller shows superior performance compared to a traditional PID flight controller for both rigid and flexible cases. Applications of adaptive control for active vibration suppression and flow control will also be discussed briefly.