The complexity of the plant under control is included in testing and development by adding a mathematical representation of all related dynamic systems.
The value of each electrically emulated sensor is controlled by the plant simulation and is read by the embedded system under test (feedback).
The tight development schedules associated with most new automotive, aerospace and defense programs do not allow embedded system testing to wait for a prototype to be available.
Aircraft and land vehicle development programs are using desktop and HIL simulation to perform design, test, and integration in parallel.
HIL simulation is a key step in the process of developing human factors, a method of ensuring usability and system consistency using software ergonomics, human-factors research and design.
For real-time technology, human-factors development is the task of collecting usability data from man-in-the-loop testing for components that will have a human interface.
Sensors communicate the demanded flight response and then apply realistic force feedback to the fly-by-wire controls using motors.
Likewise for problematical points in parameter space that may not be easily reachable with a real plant but must be tested against the hardware in question.
"[2] Since in-vehicle driving tests for evaluating performance and diagnostic functionalities of Engine Management Systems are often time-consuming, expensive and not reproducible, HIL simulators allow developers to validate new hardware and software automotive solutions, respecting quality requirements and time-to-market restrictions.
In a typical HIL Simulator, a dedicated real-time processor executes mathematical models which emulate engine dynamics.
Finally, the Electronic Control Unit (ECU) under test is connected to the system and stimulated by a set of vehicle maneuvers executed by the simulator.
[1][3][4] When testing a new ECU software release for example, experiments can be performed in open loop and therefore several engine dynamic models are no longer required.
[5] Since complexity of models processing is dumped, a full-size HIL system is reduced into a portable device composed of a signal generator, an I/O board, and a console containing the actuators (external loads) to be connected to the ECU.
In recent years, HIL for power systems has been used for verifying the stability, operation, and fault tolerance of large-scale electrical grids.
[8] These types of simulation platforms enable the evaluation and testing of large-scale power systems in a realistic emulated environment.
As a result, many errors are found that have to be solved during the commissioning, with the risks of personal injuries, damaging equipment and delays.