Hardware-in-the-loop Labor

Hardware-in-the-loop (HIL) simulation represents an efficient method of testing and validating the functionality of system components in embedded electronic and mechatronic vehicle systems (for example, automotive control devices in an E/E network) at an early stage of their development. It consists of simulating the technical environment (e.g. the vehicle) to the necessary extent and feeding input data to the hardware to be tested. Typically, HIL testing involves bus/restbus, sensor, and vehicle/driving dynamics simulation. In the HIL laboratory at the CARISSMA research centre, new methods are being developed for testing complex safety systems based on environment sensors. The focus is on increasing the depth of testing and the coverage of the test space to allow efficient and consistent testing of automatic drive functions and integral safety concepts. This involves developing and analysing new test methods, for example, in the field of model-based testing, mixed reality and simulation-based sensor stimulation. In the latter case, simulated data is supplied through target simulators for actual environment and environmental sensors, as appropriate to the respective sensor.

Research carried out at the HIL Laboratory looks into methods of testing environmental-sensor-based driving functions. The objective is to perform part of the testing procedure in a laboratory environment, so as to reduce the cost and time expenses of the test. It also enables more attention to be given to safety-critical test cases, than, for instance, in real-life driving tests. One concrete objective is to improve radar target simulators to enable them to differentiate between such targets as lorries, cars, pedestrians, etc. There are also plans to develop a camera simulation system with direct frame transmission to the controller under test. Moreover, a method is being developed to allow benchmark analysis of sensors and data fusion algorithms. In addition, the development of a distributed test environment planned with other laboratories, in which various participants in a simulation are connected via a LAN. The degree of realism varies all the way from pure simulation to real-life vehicles.

Equipement

NI PXI system (NI PXIe-1085)
16 analog inputs
16 analog outputs
8 relay outputs
Wheel speed generator, 4 channels
6 CAN interfaces
4 FlexRay interfaces
2 LIN interfaces
8 PSI5 channels
16 PWM input channels
16 PWM output channels
1 Gb/s Ethernet
Freely programmable FPGA
Frequency generator
Oscilloscope
Resistance simulator, 8 channels
8 voltage measurement channels (-75 – 75V)
8 current measurement channels (0 – 50A)
GPS simulator (NI USRP RIO)

2 NVIDIA Drive PX2
1 dSPACE MicroAutoBox II

4 desktop workstations with Ubuntu as operating system
1 laptop workstation with Windows 7 as operating system
1 HIL system workstation with Windows 7 as operating system

Soldering station
Mains plug
Integrated multimeter
Integrated laboratory power supply unit
Oscilloscope

55“ screen for presentations
Conference table with six places

Example Applications

The HIL system is equipped with all common bus interfaces currently employed in the automotive field (CAN, LIN, FlexRay) with which complex restbus simulations can be generated. The open NI PXI system makes it possible to integrate new future standards in the system, such as BroadR-Reach Ethernet.

The real-time VeriStand (National Instruments) environment enables – by way of MIL and SIL
testing – the integration of software components from different sources (such as MATLAB, Simulink models, C-Code, LabVIEW, etc.); these may be linked to each other in any way or directly connected to the inputs and outputs of the HIL system.

Driving simulation can be employed to help with testing functions that are dependent on the driving situation. In CARISSMA HIL, driving simulation is realised using both CarMaker (IPG Automotive GmbH) software and VTD (VIRES Simulationstechnologie GmbH). Driving simulation generates all the ego vehicle data that is required to drive the subsystem. It supplies the data for test bus simulation, which is transmitted to a controller via CAN, LIN, FlexRay and in future also Automotive-Ethernet. In addition, the data can be used to feed models and software modules on the real-time computer of the HIL system. Conversely, it is also possible to feed the output of the subsystem being tested by way of a closed-loop circuit through the HIL system to the driving simulator and to change the latter’s simulation parameters. All connected components, (e.g. driving simulator, controllers, software modules, sensors, etc.) are interconnected and, where appropriate, configured using the Veristand (National Instruments) software.

The CARISSMA HIL system is fitted with a freely programmable FPGA unit, which, among other things, enables the simulation of proprietary controller interfaces. The FPGA can also be flexibly employed to generate rarely used sensor signals or to expand existing interfaces without the need to provide a dedicated card.

A GPS simulator (NI USRP RIO) is integrated in the CARISSMA HIL system. This enables the testing of the ‘Determine Location’ function with simulated GPS signals, as required, for instance, by navigation systems or other position-dependent assistance and safety functions. The GPS simulator generates the signals of up to 12 satellites, whereby the user is able to define the power level of each simulated satellite. It is also possible to generate separate movement profiles for the satellites. It is also possible to simulate the typical kinds of signal interference occurring with GPS satellites that can lead to positional inaccuracies in terrestrial receivers.