- Curriculum Vitae
- liu98 (at) illinois (dot) edu
- Doctoral Candidate (Expected Graduation – May 2014)
- M.S. – University of Illinois at Urbana-Champaign, 2011
- B.Eng. (Hons.) – University of Birmingham, UK, 2008
- B.S. – Harbin Institute of Technology, China, 2008
- Research Interests: System Identification, Learning Control, Motion Control, Automatic Guidance
The overall focus of my research within Alleyne Research Group is on the identification of systems that are asked to execute the same task repetitively. One example of these systems is manufacturing processes. The repetitive nature of such systems allows us to adopt a notion similar to Iterative Learning Control. More specifically, the information obtained in one trial can be passed to a subsequent trial to improve the parameter learning. This identification method is shown to be valuable for both Linear Time Varying systems and Linear Time Invariant systems.
For Linear Time Varying systems whose parameters have discontinuous changes, classical adaptive estimation has the limitation of slower transient than desirable. For many manufacturing systems, the task set for the control system repeats itself from part to part. This will allow us to adopt Iterative Learning Identification method and achieve convergence in the iteration domain instead of the time domain, which will in turn improve the transient identification result. One example of the applications is a pick and place robot shown in the video below.
For Linear Time Invariant systems which are asked to repeat their trajectories, Iterative Learning Identification can be adopted to achieve smaller parameter variance. This identification method has been verified using a John Deere 7700 tractor. The lateral dynamics model of the tractor is obtained using Iterative Learning Identification method, and a feedback controller is designed based on the identified model. This feedback controller is verified in a hardware-in-the-loop test, and the tractor tracking results with lane changes are shown in the video below.
Selected Publications
1. N. Liu and A. Alleyne, “Iterative Learning Identification Applied to an Automated Off-highway Vehicle” Accepted for publication in IEEE Transactions on Control Systems Technology, 2013
2. N. Liu and A. Alleyne, “Time-varying Norm Optimal Iterative Learning Identification”, Proceedings of the 2013 American Control Conference, Washington, D.C., 2013 (Best Presentation in Session Award)
2. N. Liu and A. Alleyne, “Norm Optimal Iterative Learning Identification for Linear Time Varying Systems”, Proceedings of ASME Dynamic Systems and Control Conference, 2012
3. N. Liu and A. Alleyne, “Iterative Learning Identification for an Automated Off-highway Vehicle”, Proceedings of the 2011 American Control Conference, San Francisco, CA, June29-July1, 2011 (Best Presentation in Session Award)
