This study proposes a collaborative robot-based gait simulation system that reproduces prosthetic knee motion and enables quantitative evaluation of control algorithm performance under controlled conditions. The system generates repetitive gait motions from input hip flexion–extension trajectories derived from normative gait data. To validate the system, we evaluated its repeatability, kinematic reproducibility, and control response. Repeatability was assessed by applying identical input trajectories multiple times and quantifying the resulting output variability in terms of the root mean square error (RMSE) and standard deviation. Kinematic reproducibility was evaluated by comparing the simulated knee joint motion of a passive prosthesis with reference gait data from amputees, based on RMSE values and correlation coefficients. In addition, the response characteristics of a microprocessor-controlled prosthetic knee (MPK) were analyzed under repeated input conditions, and the MPK exhibited consistent Lock/Unlock state transitions throughout the gait cycle. The results demonstrate that the proposed system achieves high repeatability and reliably reproduces both the kinematic behavior and the control responses of prosthetic knees. Therefore, the system can serve as an objective and controlled platform for the preclinical evaluation of prosthetic knee control algorithms.
