Introduction to Recently Developed HIL Methods: Impulse Response Functions and Non-simultaneous Iterative Hybrid Simulation/Testing

Abstract

Complex mechanical systems usually consist of subsystems that interact dynamically with each other. If the subsystems are separated from each other and partly exist as numerical model and as real hardware, then one speaks of hardware in the loop (HIL), cyber-physical or hybrid systems. In this presentation, two recently developed methods for the coupling of experimental and numerical subsystems into an overall system are presented. In both methods, no explicit mathematical models are required and the task of parameter identification is completely omitted. In the first method, the hardware is characterized with impulse response functions. This leads to a linearized description of the component around an operating point. In addition to the presentation of the basic idea, some examples (e.g. rubber bearings) are shown. This method can be used for an ?as it is? representation of existing constructions in numerical time integration. In the second approach (non-simultaneous iterative hybrid simulation/testing), the test bench and the numerical simulation are driven repeatedly in a loop. After each loop, the compatibility conditions are checked. If they are fulfilled, both systems behave according to the cutting force principle as if they were actually coupled. No dynamics are neglected and nonlinearities are mapped. The data exchange is not critical, a communication via EMail would be possible. In addition to the basic idea, a wheel suspension is shown as an example, in which the shock absorber is present as hardware.