Application of Hardware-in-the-Loop Simulation for the Development and Testing of Advanced Control Systems for Joint Wear Simulators

Hardware-in-the-loop (HIL) simulation is an advanced technique for developing and testing complex real-time control systems. This paper presents the benefits of HIL simulation to develop, test and validate advanced control algorithms used in an artificial joint wear simulator for the tribological testing of prostheses. A benchtop HIL setup is created for experimentation, controller verification, and validation purposes, allowing different control strategies to be tested rapidly in a safe environment. The HIL simulation attempts to replicate similar joint motion and loading conditions of that of the spinal wear simulator. The simulator contains a four-bar link powered by electromechanical actuators. As a result, the implant articulates with an angular motion specified in the international standards, ISO-18192-1, that defines fixed sinusoid motion and load profiles for wear testing of both lumbar and cervical disc implants. Using a PID controller, a velocity-based position control algorithm was developed to interface with the benchtop setup that performs HIL simulation. The simulation results strongly support the efficacy of the test setup using HIL simulation to verify and validate the accuracy and robustness of the prospective controller before its deployment into the spinal wear simulator. This method of testing controllers enables a wide range of possibilities to test advanced control algorithms that can potentially utilize real-world data of patients performing daily living activities that place adverse demands on the artificial joint.