Research projects


Reconfiguration of Control in Flight for Integral Global Upset Recovery



The EU-FP7 project RECONFIGURE aims to develop fault detection and fault-tolerant control techniques that facilitate automated handling and help alleviate the pilot's workload during so-called off nominal/abnormal events, and optimize the aircraft's status and flight. This must be performed while maintaining current aircraft safety levels.

Selected publications:

  • H. Alwi and C. Edwards, A Fault Tolerant Integral Sliding Mode Control Allocation Scheme for the RECONFIGURE Benchmark Problem, American Control Conference, 2014.
  • H. Alwi, L. Chen and C. Edwards, Reconstruction of Simultaneous Actuator and Sensor Faults for the RECONFIGURE Benchmark Using a Sliding Mode Observor, accepted in 19th IFAC World Congress, 2014.


Advanced Fault Diagnosis for Sustainable Flight Guidance and Control





ADDSAFE comprises a consortium of European industrial partners, research establishments and universities to address the challenge of the future 'sustainable' aircraft which are cleaner, quieter, smarter and more affordable. The overall aim of the project, termed, is to contribute to the aircraft's structural design and performance optimization thanks to advanced Fault Detection and Diagnosis (FDD) in the Flight Control System (FCS). More precisely, it can be demonstrated that improving the fault diagnosis performance in FCS allows optimization of the aircraft's structural design (resulting in weight saving), which in turn helps to improve aircraft performance and to decrease its environmental footprint (i.e. fuel consumption and noise).

Selected publications:

  • H. Alwi and C. Edwards. Development and Application of Sliding Mode LPV Fault Reconstruction Schemes for the ADDSAFE Benchmark. ADDSAFE special issue for Control Engineering Practice, DOI: 10.1016/j.conengprac.2014.05.003, 2014.
  • H. Alwi and C. Edwards. Second Order Sliding Mode Observers for the ADDSAFE Actuator Benchmark Problem. Control Engineering Practice, DOI:, 2013.
  • H. Alwi and C. Edwards. Robust Fault Reconstruction for Linear Parameter Varying Systems Using Sliding Mode Observers. International Journal of Robust and Nonlinear Control, DOI: 10.1002/rnc.3009, 2013.
  • H. Alwi, C. Edwards, An Adaptive Sliding Mode Differentiator for Actuator Oscillatory Failure Case Reconstruction. Automatica, Vol. 49(2):642-651, 2013.



The objective of the AG16 project was to conduct and coordinate research activity in Europe for developing fault-tolerant control (FTC) techniques with application to aircraft, which includes fault detection and diagnosis (FDD) and reconfigurable flight control in the presence of malfunctions in actuators, control surfaces and sensors. Specifically, the action group will address the integration of new, advanced methods for fault detection and diagnosis together with schemes for control system reconfiguration applied to a representative, nonlinear Matlab/Simulink aircraft benchmark model, the techniques will also be evaluated/assessed in a flight simulator at Delft University of Technology.

Selected publications:

  • Edwards, T., J.J. Lombaerts, M.H. Smaili, Fault Tolerant Flight Control – A Benchmark Challenge. Springer Verlag, 501-517, 2010.
  • H. Alwi, C. Edwards and C.P. Tan. Fault Detection and Fault Tolerant Control Using Sliding Modes. Springer Verlag, 2011.
  • H. Alwi, C. Edwards, O. Stroosma and J.A. Mulder. Evaluation of a Sliding Mode Fault-Tolerant Controller for the El Al Incident, AIAA journal of Guidance Control and Dynamics, Vol. 33(3):677-694, 2010.
  • H. Alwi, C. Edwards, O. Stroosma and J.A. Mulder. Fault Tolerant Sliding Mode Control Design with Piloted Simulator Evaluation, AIAA journal of Guidance Control and Dynamics, 31(5):1186-1201, 2008.
  • H. Alwi and C. Edwards. Fault Tolerant Control Using Sliding Modes with On-line Control Allocation. Automatica, Vol. 44(7):1859-1866, 2008.

Robustness and adaptivity: advanced control and estimation algorithms for the transverse dynamic atomic force microscope




Observing the dynamic behavior and interactions of single bio-molecules is a long-standing goal to facilitate biomedical research. Standard practice is to use one of several types of scanning probe microscopes (SPMs) - principally atomic force microscopy (AFM). The principle of an AFM is simple: a horizontally-oriented cantilever with a very sharp tip is moved across the object of interest, allowing the capture of a three-dimensional topographical image. A significant challenge to imaging bio-molecular interactions is that the forces typically present between the probe and the sample disturb or even damage the bio-molecules.

To counter these issues, we will combine the latest advances in control theory with the novel SPM instrumentation, currently in development in Bristol, to produce a new scanning probe microscope capable of imaging these fragile samples without damaging them. The challenges will be to achieve practical control at bandwidths above 1MHz and to understand and exploit the nonlinear dynamics for better data interpretation. The resulting instrument will be a true non-contact imaging device capable of comparable spatial resolution and lower interaction forces than AFMs, and will display pico-Newton force-sensitivity providing a wealth of information from direct observation of the interacting bio-molecules.

Selected publications:

  • T. Nguyen-Tien, S.G. Khan, C. Edwards, G. Herrmann, R. Harniman, S.C. Burgess, M. Antognozzi and M. Miles, ‘Shear force reconstruction in a vertically oriented probe microscope using a super-twisting observer’. Proc of the IEEE Conference on Decision and Control, Florence, Italy, 2013.
  • T. Nguyen, S.G. Khan, C. Edwards, G. Herrmann, L. Picco, R. Harniman, S.C. Burgess, M. Antognozzi and M.J. Miles, ‘Estimation of the Shear Force in Transverse Dynamic Force Microscopy Using a Sliding Mode Observer’. Proc of the American Control Conference, Washington, 2013.







This project funded by the European Space Agency in conjunction with DEIMOS-Space Systems (Spain) and Astrium (France) investigated the application of sliding mode observers for fault detection in a satellite demonstrator project. The objective here was to demonstrate increased Technology Readiness Levels for sliding mode observer-based fault detection schemes for space applications.

Selected publications:

  • A. Marcos, H. Alwi, C. Edwards, A. Falcoz and E. Bornschlegl. Verification & Validation of a Satellite Fault Detection and Isolation Scheme Based on Sliding-Mode Observers, IFAC Symposium on Fault Detection and Safety of Technical Process, 2012.
  • H. Alwi, C. Edwards and A. Marcos, FDI for a Mars Orbiting Satellite Based on a Sliding Mode Observer Scheme, Conference on Control and Fault Tolerant systems (SysTol’10), 2010.

'Active Aircraft'






In response to the ACARE 2020 (Advisory Council for Aeronautics Research in Europe) target of a 50% reduction in emissions by the year 2020, aircraft manufacturers are looking to develop technology to lower in-flight drag, thereby increasing fuel efficiency. In collaboration with the University of Warwick, Queen's University Belfast and Sheffield University, the 'Active Aircraft' project developed novel nonlinear estimation schemes, which are underpinned by rigorous theory but which are practical enough to be implemented on-line for drag estimation and fault-tolerant flow control.

Selected publication:

  • J.M. Andrade Da Silva, Halim Alwi, Christopher Edwards, Sliding Mode Based On-Line Drag Estimation of a Simulated Aircraft Over a Wireless Network, 20th Mediterranean Conference on Control and Automation, 2012.