The objective of this study is to optimize the joint structure and control method of a wearable exoskeleton-based training device that can reduce physical burden while improving human motor performance. In particular, the study focuses on knee joint motion and aims to establish a practical design methodology by integrating ergonomics and robotics.

In this year, a preliminary investigation was first conducted on prosthetic leg design, with special attention to human compatibility, structural stability, and motion-following capability. The survey showed that multi-link mechanisms are widely used in prosthetic systems because they can better reproduce biologically similar joint trajectories while improving stability during motion and ground contact. Based on these findings, a four-bar linkage mechanism was introduced into the connection structure of the knee and foot sections of the training device, and the arrangement of the links was optimized. In addition, a five-bar linkage mechanism was also designed and examined in order to explore the possibility of achieving higher adaptability and motion performance. As a result, the introduction of both four-bar and five-bar linkage mechanisms improved the stability of the coupling behavior in the foot section compared with the previous structure. In particular, the optimized link arrangement contributed to better motion tracking, reduced unwanted displacement, and enhanced mechanical support during movement. These results indicate that adopting multi-link structures is effective for improving the structural stability and motion compatibility of the device. On the other hand, it also became clear that the increase in structural complexity made load-force control more difficult. Because the force transmission path becomes more complicated in a multi-link mechanism, it is harder to apply the desired training load accurately and consistently. This suggests that while mechanical stability can be enhanced through link-based design, the control system must also be improved to ensure precise and coordinated load application.

Overall, this study demonstrated the effectiveness of introducing multi-link mechanisms into the training device design and clarified both the advantages and the remaining challenges. Future work will focus on developing solutions to the control difficulty caused by the more complex linkage structure, and on establishing an integrated optimization method that considers both mechanism design and control system design simultaneously.