This is a brief introduction of Hardware In the Loop Simulation. More precisely, the HIL in this film means CONTROLLER HIL. Sometimes it is also called CHIL. There are controller/power/mechanical level HILs for different simulated parts of the system. CHIL is one of these useful tools for controller test, especially for control algorithm verification in controller development, test, and commissioning. Many companies provide very useful CHIL tools, e.g. dSPACE, Opal-RT, Speedgoat, Typhoon HIL, ETAS etc.