LI Youwei, JIN Huaiping, YANG Biao, CHEN Xiangguang
Control Engineering of China.
2025, 32(4):
653-663.
Soft sensor technology has been widely used to estimate the key difficult-to-measure variables in the process industry. However, its performance is often limited by problems such as lack of labeled samples, improper feature extraction, and poor performance of the single model. Therefore, a new semi-supervised ensemble soft sensor is proposed, which integrates latent feature extraction, semi-supervised learning, and ensemble learning into the same modeling framework to achieve complementary advantages. Firstly, diverse latent features are extracted from process data by the extreme learning machine auto-encoder (ELMAE), and a set of diverse Gaussian process regression (GPR) base models are established. Then, to augment the limited labeled sample set, pseudo-labeled samples are generated for each base model by a multi-learner pseudo-label generation strategy. Finally, the base models are retrained based on the augmented labeled sample set, and the base models are integrated to build the final soft sensor model. The proposed method is applied to the prediction of substrate concentration in the process of chloromycin fermentation, and the experimental results verified the effectiveness and superiority of the proposed method.