What is HIL
Hardware-in-the-Loop, or hardware and software simulation, is an approach to testing the software of electronic systems by connecting them to a simulator of adjacent systems or environments.
For example, to work out the algorithms of the chassis release system, a special computer is connected to the control unit with an accurate programming model of the chassis and an accurate simulation of signals from the chassis. For the control unit, this looks like a regular operation with a real unit.
HIL is to a device like a flight simulator for a pilot. HIL spoofs signals by tricking the “senses”, trains and tests “skills”, algorithms and scripts.
All systems interact with real signals and in real time. Today, simulators of control units and objects, sensors, environment, related systems and controllers, the whole system are created in this way. Control units, hydraulic and electric drives, communication and navigation systems, radars, autopilot systems, etc. are tested.
HIL and prototyping in R&D
HIL is also used for product prototyping. The mock-up models and “imitates” the behavior of the product itself (which is still being developed) when interacting with the environment. The HIL system simulates the environment of the product.
HIL simulators can be used on both sides, which allows you to smoothly, as products and algorithms are ready, move from two-sided simulation to testing real systems.
Test earlier, safer, cheaper
HIL tests begin long before the product, related systems or landfill is ready. In advance, in laboratory conditions, you can see the behavior of the system and better prepare for field tests. In HIL mode, thousands of semi-natural tests are performed in a short time - without endangering people and equipment.
HIL for software debugging and improvement
The results of HIL's experiments provide feedback to embedded software developers and help them implement, fix, and improve bold innovations. HIL helps you reproduce an experiment, test hypotheses, and gather statistics. At the same time, unlike computer simulation, work is carried out with real devices and signals - and in real time.
HIL platform National Instruments
National Instruments' platform builds on over 40 years of experience in automated measurements and testing of the latest electronic devices, electromechanical systems, automatic control systems, bench tests and scientific experiments.
The platform has collected the best practices for solving problems in aviation and space, energy, automotive, shipbuilding, railway transport, medical instrumentation, and nuclear physics. Today it is an example of a solid, yet open and dynamically developing platform for responding to new engineering challenges.
A typical HIL system includes a test object, data acquisition equipment, and a software model that receives, processes, and outputs signals to simulate real-world scenarios.
The execution of the model must take place in hard real time, which in modern devices means a time scale and delay in units of microseconds. Hardware for software and hardware simulation is based on real-time processors and FPGAs, as well as special software such as NI VeriStand.
Data acquisition equipment , as a rule, also includes special solutions for switching and signal conditioning and additional devices. So, it is typical to use external powerful amplifiers, load simulators, devices for simulating a break and introducing other malfunctions.
Rigging or cable solutions for convenient and reliable connections take a special place in large systems designed to test different units.
Software for automation of tests , analysis and storage of results, special communication protocols, loads, simulation of faults, etc. complement the functionality of the system.
NI PXI and NI CompactRIO
The NI PXI and NI CompactRIO are modular FPGA instrumentation systems that run a real-time or Windows operating system. Devices and devices of these formats provide work with thousands of signals and sensors and act as both measuring complexes and simulators of systems in real time.
As a rule, the composition of the system is selected from ready-made modules.
NI SLSC (Switch, Load, and Signal Conditioning) is a modular signal conditioning system designed specifically for HIL applications and open to the user. SLSC allows you to expand the signal ranges of PXI and CompactRIO, add the necessary special termination, while maintaining the conciseness and modularity of the system.
NI HIL Simulator
The NI HIL Simulator systems are system templates for common HIL tasks, pre-configured based on industry best practices. Such complexes already contain the necessary infrastructure and system elements, and remain flexible and open to the user.
NI VeriStand - Software Core for HIL
NI VeriStand is a real-time testing software package. VeriStand provides an environment for executing and manipulating models, generating input signals, collecting, processing and storing data.
VeriStand facilitates HIL-related tasks. Thus, the transition from software simulation to real I / O channels occurs by changing several channel settings.
The VeriStand architecture separates the real-time engine and the operator's workstation, providing both determinism of execution and customization of the interface and software for organizing tests during operation.
VeriStand supports a variety of models including AMESim, NI MATRIXx SystemBuild, Dymola, MapleSim, ITI SimulationX, and is expandable with LabVIEW, ANSI C / C ++, ASAM XIL, and more.
The MathWorks Products
The openness of the National Instruments platform, its flexibility allows you to choose the software packages necessary for the best solution to the problem. Models created in MathWorks Simulink, Simscape, and StateFlow easily integrate into VeriStand for HIL execution on National Instruments hardware or for joint parallel execution.
National Instruments and The MathWorks Inc. are actively collaborating to provide users with the best hardware and software simulation tools.
FPGA and Real-Time Programming
The LabVIEW graphical programming environment for engineers and scientists makes it easy to solve any measurement, data acquisition, and test challenge. National Instruments' hardware control is most often programmed in LabVIEW.
The LabVIEW Real-Time and LabVIEW FPGA Modules make it easy to program real-time controllers and FPGA devices, without the complexity of traditional tools like VHDL and Verilog. The LabVIEW Control Design and Simulation Module and Model Interface Toolkit make it easy to create models and integrate third-party models.
Data analysis in DIAdem
DIAdem helps you store, search, visualize, and analyze large amounts of measurement and simulation data from tests, both as part of the VeriStand interface and in a standalone application.
Tests with NI TestStand
The NI TestStand test management environment allows you to organize sequential and conditional execution of tests and scripts, save results and reports, and other non-specific test tasks.