By considering autocorrelation
among process data, canonical variate
analysis (CVA) can noticeably enhance fault detection performance.
To monitor nonlinear dynamic processes, a kernel CVA (KCVA) model
was developed by performing CVA in the kernel space generated by kernel
principal component analysis (KPCA). The Gaussian kernel is widely
adopted in KPCA for nonlinear process monitoring. In Gaussian kernel-based
process monitoring, a single learner is represented by a certain selected
kernel bandwidth. However, the selection of kernel bandwidth plays
a pivotal role in the performance of process monitoring. Usually,
the kernel bandwidth is determined manually. In this paper, a novel
ensemble kernel canonical variate analysis (EKCVA) method is developed
by integrating ensemble learning and kernel canonical variate analysis.
Compared to a single learner, the ensemble learning method usually
achieves greatly superior generalization performance through the combination
of multiple base learners. Inspired by the ensemble learning method,
KCVA models are established by using different kernel bandwidths.
Further, two widely used
T
2
and
Q
monitoring statistics are constructed for each model.
To improve process monitoring performance, these statistics are combined
through Bayesian inference. A numerical example and two industrial
benchmarks, the continuous stirred-tank reactor process and the Tennessee
Eastman process, are carried out to demonstrate the superiority of
the proposed method.