Verification and Validation of Advanced Control Systems for A Spinal Joint Wear Simulator

Abstract

Wear simulation aims to assess wear rates and their dependence on factors like load, kinematics, temperature, and implant orientation. Despite its significance, there's a notable gap in research concerning advancements in simulator control systems and the testing of clinically relevant waveforms. This study addresses this gap by focusing on enhancing the conventional proportional-integral-derivative (PID) controller used in joint simulators through the development of a fuzzy logic-based controller. Leveraging a single-input-multiple-output (SIMO) fuzzy logic control system, the study aimed to improve displacement control, augmenting the traditional Proportional-Integral (PI) tuning approach. Implementation and evaluation of a novel Fuzzy-PI control algorithm were conducted on the Leeds spine wear simulator. The study also included testing of daily-living (DL) profiles, particularly from the hip joint, to broaden the scope of simulation scenarios. While both the conventional PI controller and the Fuzzy-PI controller met ISO tolerance criteria for the spine flexion-extension (FE) profile at 1Hz, the Fuzzy-PI controller demonstrated superior performance at higher frequencies and with DL profiles due to its real-time adaptive tuning capability. The Fuzzy-PI controller represents a significant advancement in joint wear simulation, offering improved control functionalities and a more accurate emulation of real-world physiological dynamics.