A First Experience with Multidimensional Contact Real-Time Hybrid Substructuring: Toward Testing of Foot Prostheses

Real-time hybrid substructuring (RTHS) is a promising approach to investigate the influence of foot prostheses on the gait pattern in versatile situations, while avoiding the necessity to model the prosthesis and its ground interaction. A numerical gait simulation is coupled in real-time to a prosthesis prototype on a test rig using sensors and actuators. However, synchronization errors make such experiments prone to instabilities. Thus, methods are required to ensure robust and stable RTHS experiments. In previous work, we developed promising methods using a one-dimensional contact RTHS experiment. In this contribution, we show our first experience with multidimensional contact RTHS in order to take the next step to enable foot prosthesis RTHS experiments. We present the design of a simplified planar foot prosthesis RTHS setup. Furthermore, we show the first results of a virtual RTHS test, where test stability is ensured through the application of normalized passivity control (NPC). From these results, we conclude that our approach is promising to extend our previously developed methods to the multidimensional case.