Throughout industrial development, with so many products made and sold, and especially with the need to use the principles of sustainability, the idea of using the already existing systems to their maximum capacity and repairing these systems to extend their life has also emerged. An entire system performance monitoring department was thus implemented. It received the name of the Products Health Management (PHM) department. The production management side showed interest in the advancement and integration of PHM technologies to improve the capabilities of the robotic systems used but not only. The present paper proposes innovative methods for monitoring a hexapod robot when certain errors occur in its kinematic response due to uncertain defects. DLAC criterion was used until now only for frequency shifts in monitoring of systems under vibrations. Using an improved DLAC criterion for errors in path planning or changes in other types of characteristics over a robot is an innovative method to improve PHM.