Recent developments in hardware-in-the-loop testing

Future applications of mechatronic systems will be characterized by a high degree of digitization enabling the integration of numerous innovative functions. The validation and reliability analysis of such complex systems often requires the realization of cost intensive full system prototypes and the evaluation of field tests. Innovative technologies are therefore integrated slowly in industrial sectors that focus on system reliability. Hence, there is a strong interest in a reliability orientated development and test process for complex mechatronic systems.The integration of real-time simulations in test environments allows efficient development and verification of the individual components of a mechatronic system in many cases. Currently, this especially applies for the test-driven development of embedded control units and their corresponding software. A reduced number of field tests, the automated run of test procedures and the application of error injection methods can be achieved by the widely used Hardware-in-the-Loop (HIL) technique. In signal level HIL tests, an existing control unit is connected to a virtual real-time simulation of the residual system. If however the device under test includes a mechanical or power electrical interface, the coupling of the test object to a virtual residual system requires the application of a mechanical or power electrical HIL interface. Current activities aim for this extension of In-the-Loop technologies for the validation of mechanical and power electronic subsystems.This paper highlights the potential of combined signal level, mechanical level and power electrical HIL tests for the validation of complex mechatronic systems in an early phase of design. The paper also points out the key topics of test-driven development, real-time simulation and the realization of hybrid test environments by means of mechanical and power electrical HIL interfaces.