Past research interests

#### Performance Analysis of perioic controllers for disturbance rejection and robust stabilization

We conduct a performance analysis of nonlinear periodically time varying
sampled-data controllers acting upon a linear time invariant plant. Time invariant
controllers are distinguished from strictly periodically time varying controllers. For a
given nonlinear strictly periodic controller, a time invariant controller is constructed.
Necessary and sufficient conditions are given under which the time invariant controller
gives strictly better control performance than the time invariant controller
from which it was obtained, for the the rejection of L_p disturbances, and the robust stabilization of L_p unstructured perturbations.

Co-workers: Professor Cishen Zhang (Swinburne University)

Publications

Publications

#### Journal Articles

- Schmid, R.., Limitations of Nonlinear Discrete Periodic Control for Disturbance Attenuation and Robust Stabilization,
*Automatica*
42 (2006) pp. 2151-2158.
- Schmid, R. and C. Zhang, Performance Analysis of Nonlinear Periodic Sampled-data Controllers for L_p Disturbance Rejection,
*IEEE Transactions on Automatic Control *, Vol. AC-48, (2003), pp. 1385-1389.
- Schmid, R. and C. Zhang, Performance Analysis of Periodic control for H_2 and mixed H_2 / H_infinity Sampled-Data Control,
* The Transactions of the South African Institute of Electrical Engineers*, Vol. 93, No. 2, (Jun. 2002), pp.73-77.
- Schmid, R. and C. Zhang , Performance Analysis of Periodic Control
for l_1 and l_infinity Disturbance Rejection,
*Asian Journal of Control*, Vol 3, No 3, 2001, pp 240-247.
- C. Zhang, J. Zhang and R. Schmid, On l_p disturbance rejection using periodic
feedback control,
* Systems & Control Letters * 38 (1999) pp 227-234.

#### Conference Papers

- Schmid, R. Limitations of nonlinear periodic sampled-data control
for robust stabilization,
*17th IFAC World Congress *, Seoul, Korea, July 2008.
- Schmid, R. Limitations of Nonlinear Discrete Periodic Control for Robust Stabilization,
* 5th ASCC Asian Control Conference* Melbourne, July 2004.
- Schmid, R. and C. Zhang, Performance Analysis of Nonlinear Periodic Control for l_p Disturbance Rejection,
*4th ASCC Asian Control Conference*, Singapore, September 2002.
- Schmid, R. and C. Zhang, Performance Analysis of Periodic Control for L_1 and L_infinity Sampled-data Control,
*IEEE Third International Conference on Control Theory and Applications,* Pretoria, South Africa, December 2001.