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

## TL;DR

This paper introduces a new fuzzy logic-based controller for spinal joint wear simulators, improving control accuracy and adaptability for realistic simulation scenarios.

## Contribution

A novel Fuzzy-PI control algorithm is developed and validated for joint wear simulators, enhancing displacement control and adaptability.

## Key findings

- The Fuzzy-PI controller outperformed conventional PI controllers at higher frequencies and with daily-living profiles.
- The Fuzzy-PI controller met ISO tolerance criteria and demonstrated real-time adaptive tuning capabilities.
- Testing on the Leeds spine wear simulator confirmed improved emulation of physiological dynamics.

## Abstract

Wear simulation aims to assess wear rates and their dependence on factors like load, kinematics, temperature, and implant orientation. Despite its significance, there is 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, this study aimed to improve displacement control, augmenting the traditional proportional–integral (PI) tuning approach. The implementation and evaluation of a novel Fuzzy-PI control algorithm were conducted on the Leeds spine wear simulator. This study also included the testing of dailyliving (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 1 Hz, 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 more accurate emulation of real-world physiological dynamics.