Digital competence is an essential skill for pre-service teachers, and self-regulation is an important factor in this competence. However, lack of emotional support often affects development of students' digital competence. Therefore, an emotional support-embedded robot-based self-regulated learning (ES-RSRL) system was developed. This ES-RSRL approach was proposed to promote learners' self-regulation and enhance pre-service teachers' digital learning resource development competencies. To evaluate the effectiveness of this approach, 54 pre-service teachers majoring in the arts were recruited, with 27 (10 males and 17 females) assigned to the experimental group using the ES-RSRL approach, and 27 (12 males and 15 females) assigned to the control group using the traditional Robot-based Self-Regulated Learning (C-RSRL) approach. The results showed that the ES-RSRL approach significantly improved pre-service teachers' digital learning resource development competencies, enhancing their extrinsic motivation and self-regulation. The interviews further revealed that the ES-RSRL approach not only enhanced students' learning efficiency. Therefore, we present an in-depth discussion on future research, and offer suggestions for researchers and teachers interested in using robots in educational environments.