TY - GEN
T1 - Combined run-to-run and delta LQG control
T2 - International Conference on Control, Automation and Systems, ICCAS 2010
AU - Won, Wangyun
AU - Kwang, Soon Lee
AU - Sang, Hyun Ji
PY - 2010
Y1 - 2010
N2 - A constrained iterative learning control (ILC) technique based on a delta-form linear quadratic Gaussian (LQG) technique has been designed for overcoming model error and for numerically stable control of a rapid thermal processing(RTP). The RTP is characterized by very short sampling time and repetition of single batch. The delta form LQG control technique was applied for accurate control in high frequency caused by short sampling time. The designed control technique, ILC, acquired both numerically stable and to overcome model error in combination with the multivariable delta form LQG technique. A structural problem of the equipment or an excessive model error may cause physically unreasonable solution computed by the delta form LQG. For this, Constraints were applied to the ILC solution to be placed on the physically reasonable area. Cubic spline approximation was used as a numerical method to approximate time-varying gain matrices. The method remarkably reduced not only a computation time, but also a data transmission time from computer to DSP board in RTP equipment. In the results of simulation, control performance was improved from batch to batch, and finally reached specification-satisfied wafer's temperature uniformity with physically reasonable lamp powers. The proposed control technique was designed for commercial RTP equipment which has 10 tungsten-halogen lamp groups and 6 pyrometers installed for heating and measure a 12-inch wafer.
AB - A constrained iterative learning control (ILC) technique based on a delta-form linear quadratic Gaussian (LQG) technique has been designed for overcoming model error and for numerically stable control of a rapid thermal processing(RTP). The RTP is characterized by very short sampling time and repetition of single batch. The delta form LQG control technique was applied for accurate control in high frequency caused by short sampling time. The designed control technique, ILC, acquired both numerically stable and to overcome model error in combination with the multivariable delta form LQG technique. A structural problem of the equipment or an excessive model error may cause physically unreasonable solution computed by the delta form LQG. For this, Constraints were applied to the ILC solution to be placed on the physically reasonable area. Cubic spline approximation was used as a numerical method to approximate time-varying gain matrices. The method remarkably reduced not only a computation time, but also a data transmission time from computer to DSP board in RTP equipment. In the results of simulation, control performance was improved from batch to batch, and finally reached specification-satisfied wafer's temperature uniformity with physically reasonable lamp powers. The proposed control technique was designed for commercial RTP equipment which has 10 tungsten-halogen lamp groups and 6 pyrometers installed for heating and measure a 12-inch wafer.
KW - Cubic spline
KW - Delta operator
KW - ILC (iterative learning control)
KW - LQG (linear quadratic gaussian)
KW - RC (repetitive control)
KW - RTP (rapid thermal processing)
UR - http://www.scopus.com/inward/record.url?scp=78751531843&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:78751531843
SN - 9781424474530
T3 - ICCAS 2010 - International Conference on Control, Automation and Systems
SP - 469
EP - 474
BT - ICCAS 2010 - International Conference on Control, Automation and Systems
Y2 - 27 October 2010 through 30 October 2010
ER -