Review of Closed-Loop Brain–Machine Interface Systems From a Control Perspective

In recent years, brain–machine interface (BMI) technology has made great progress in controlling external devices and restoring motor function for people with disabilities. To better optimize BMI system performance, in this article, we summarize and describe a universal closed-loop BMI system framework and review the latest developments over the past ten years from a control perspective. First, the basic BMI systems with open-loop and closed-loop structures are introduced in chronological order. Second, the units of the universal closed-loop BMI system, i.e., the decoder, encoder, and auxiliary controller, are reviewed and summarized in terms of principles, categories, and algorithms. Finally, from research and practical perspectives, the importance of biomimetic brain models, great challenges, and future developments are discussed based on current progress. With this analysis of the universal closed-loop framework, this review can provide necessary theoretical guidance for the research and development of BMI systems.