The development of Facial Expression Recognition (FER) technology has significantly enhanced the naturalness and intuitiveness of human-robot interaction. In the field of service robots, particularly in applications such as production assistance, caregiving, and daily service communication, efficient FER capabilities are crucial. However, existing Convolutional Neural Network (CNN) models still have limitations in terms of feature representation and recognition accuracy for facial expressions. To address these challenges, we propose CAGNet, a novel network that combines multiscale feature aggregation and attention mechanisms. CAGNet employs a deep learning-based hierarchical convolutional architecture, enhancing the extraction of features at multiple scales through stacked convolutional layers. The network integrates the Convolutional Block Attention Module (CBAM) and Global Average Pooling (GAP) modules to optimize the capture of both local and global features. Additionally, Batch Normalization (BN) layers and Dropout techniques are incorporated to improve model stability and generalization. CAGNet was evaluated on two standard datasets, FER2013 and CK+, and the experiment results demonstrate that the network achieves accuracies of 71.52% and 97.97%, respectively, in FER. These results not only validate the effectiveness and superiority of our approach but also provide a new technical solution for FER. Furthermore, CAGNet offers robust support for the intelligent upgrade of service robots.

Facial expression recognition (FER) is crucial for endowing service robots with emotional perception capabilities. Achieving high-performance facial expression recognition hinges on effectively balancing the capture of subtle local textures with the understanding of overall facial configurations. However, coordinating local feature variations with global semantic dependencies in unconstrained environments while maintaining semantic alignment remains a challenge. To address this issue, we propose FER-SDAM, a network architecture based on hierarchical attention collaboration. Through a dual-attention hierarchical collaboration mechanism, this architecture introduces an Attention Consistency Loss (ACL) to explicitly align shallow structural awareness with deep global dependencies. It simultaneously captures structural sensitivity and cross-regional correlations, facilitating the effective fusion of local structural information with global semantics, thereby balancing accuracy, robustness, and computational efficiency. We conducted extensive experiments on AffectNet, RAF-DB, and their subsets containing occlusion and pose variations, achieving accuracy rates of 68.12%, 66.68%, and 88.87% on the AffectNet-7, AffectNet-8, and RAF-DB datasets, respectively. The experimental results demonstrate that FER-SDAM achieves a critical balance between accuracy and efficiency, delivering highly competitive recognition performance while maintaining low computational overhead, making it an ideal solution for real-time deployment in service robots.