Research

Decentralized Optimal Structural Control

Modern structural sensing and control technologies offer the opportunities of densely instrumenting a civil structure with a large number of control devices.  Through real-time feedback, the control devices provide forces and reduce excessive structural vibrations during earthquakes or typhoons.  However, the scalability of control systems is severely hindered by their dependence on traditional centralized control strategies.  Our pioneering research generated novel theoretical frameworks that enable the design of decentralized control systems, where control decisions are made based upon data acquired from distributed sensors located in the vicinity of a control device.  The seminal research on this topic received a Best Student Paper Award at the 2006 SPIE symposium on Smart Structures and NDE.  The non-convex optimization problems in decentralized control design are well-known to be NP-hard. Off-the-shelf numerical solvers are not available for solving such problems.  We have investigated various heuristic algorithms that enable effective decentralized structural control design.  Among others, the homotopic transformation methods through matrix inequalities have received very positive feedback from the research community, including an article on decentralized H∞ controller design published in Structural Control and Health Monitoring.  Furthering research along this line, the other important area of our research aims to formulate decentralized structural control problems through convex optimization.

Selected Publications

1. Qu, C., Huo, L., Li, H., and Wang, Y. (2014). “A double homotopy approach for decentralized H∞ control of civil structures,” Structural Control and Health Monitoring, 21(3): 269-281
   
   
2. Qu, C., Wang, Y., Law, K.H. and Li, H. (2011). “Decentralized H₂ controller design for civil structures through double homotopy transformation,” Proceedings of the 6th International Workshop on Advanced Smart Materials and Smart Structures Technologies (ANCRiSST), Dalian, China, July 25 – 26, 2011.
   
   
3. Wang, Y. (2011). “Time-delayed dynamic output feedback H∞ controller design for civil structures: a decentralized approach through homotopic transformation,” Structural Control and Health Monitoring, 18(2): 121-139.
   
   
4. Wang, Y., Law, K.H. and Loh, C.-H. (2010). “Decentralized H₂ control for civil structures through homotopic transformation,” Proceedings of the 5th World Conference on Structural Control and Monitoring, Tokyo, Japan, July 12 – 14, 2010.
   
   
5. Wang, Y., Law, K.H., and Lall, S. (2009). ” Time-delayed decentralized H∞ controller design for civil structures: a homotopy method through linear matrix inequalities,” Proceedings of the 2009 American Control Conference (ACC 2009), St. Louis, MO, June 10 – 12, 2009.
   
   
6. Wang, Y., Lynch, J.P. and Law, K.H. (2009). “Decentralized H∞ controller design for large-scale civil structures,” Earthquake Engineering and Structural Dynamics, 38(3): 377-401.
   
   
7. Wang, Y., Lynch, J.P. and Law, K.H. (2007). “Decentralized H∞ controller design for large-scale wireless structural sensing and control systems,” Proceedings of the 6th International Workshop on Structural Health Monitoring, Stanford, CA, September 11 – 13, 2007.
   
   
8. Wang, Y., Swartz, R.A., Lynch, J.P., Law, K.H. and Loh, C.-H. (2007). “Performance evaluation of decentralized wireless sensing and control in civil structures,” Proceedings of SPIE 14th International Symposium on Smart Structures and Materials & Nondestructive Evaluation and Health Monitoring, 6531: 653113, San Diego, CA, March 18 – 22, 2007.
   
   
9. Wang, Y., Swartz, R.A., Lynch, J.P., Law, K.H., Lu, K.-C. and Loh, C.-H. (2007). “Decentralized civil structural control using real-time wireless sensing and embedded computing,” Smart Structures and Systems, 3(3): 321-340.
   
   
10. Wang, Y., Swartz, R.A., Lynch, J.P., Law, K.H., Lu, K.-C. and Loh, C.-H. (2006). “Application of decentralized wireless sensing and control in civil structures,” Proceedings of the US-Taiwan Workshop on Smart Structural Technology for Seismic Hazard Mitigation, Taipei, Taiwan, October 12-14, 2006.
    
    
11. Wang, Y., Swartz, R.A., Lynch, J.P., Law, K.H., Lu, K.-C. and Loh, C.-H. (2006). “Decentralized real-time velocity feedback control of structures using wireless sensors,” Proceedings of the 4th International Conference on Earthquake Engineering, Taipei, Taiwan, October 12-13, 2006.
    
    
12. Loh, C.-H., Lu, K.-C., Wang, Y., Swartz, R.A., Lynch, J.P. and Law, K.H. (2006). “Discussion on the application of wireless active sensing unit for structural control,” Proceedings of the 4th World Conference on Structural Control and Monitoring, San Diego, CA, USA, July 11 – 13, 2006.