{{short description|Technique used in the development and testing of complex real-time embedded systems}}
'''Hardware-in-the-loop''' ('''HIL''') '''[[simulation]]''', or '''HWIL''', or '''HITL''', is a technique that is used in the development and testing of complex real-time [[embedded systems]]. HIL simulation provides an effective testing [[platform (computing)|platform]] by adding the complexity of the process-actuator system, known as a [[Plant (control theory)|plant]], to the test platform. The complexity of the plant under control is included in testing and development by adding a [[Representation (mathematics)|mathematical representation]] of all related [[dynamic systems]]. These mathematical representations are referred to as the "plant simulation". The embedded system to be tested interacts with this plant simulation.
