Hil test of the ECU of NI veristand booster car

Figure 1 Hil System integration

The combination of Ni Veristand and NI pxi platform satisfies the needs of users for the functions of I/O, computing power, signal simulation and data analysis, and is completely open and modular. "–enrico Corti, Alma Automotive.

Challenges：

Based on commercial off-the-shelf (COTS) hardware, a modular hardware in-loop (HIL) test system is developed for the real-time simulation of the engine and vehicle to reduce the number of physical tests required in the embedded software verification process.

Solution:

Based on NI Veristand real time test software and NI PXI hardware test system provides users with the required computing power, can use field Programmable gate Array (FPGA) hardware to achieve high-speed control, and various I/O can not only ensure that the Hil system can meet the current needs, It can also be extended to meet future application requirements.

Alma Automotive is a company based in northern Italy that provides customized solutions for automotive calibration, control, and testing. Alma Automotive provides pure software (model or model-based analysis) or integrated hardware and software solutions based on customer needs. Eldor Company provides automotive electronic components such as coils, sensor systems and electronic control units (ECU).

Because Hil systems can be used to automate and standardize tests, they are the standard for ECU testing. Most Hil systems available on the market offer standard features that cannot be extended or customized, and the Eldor company has chosen the Hil solution proposed by Alma Motor because the hardware and software of the program are open and tailored to their needs.

The Hil system simulates a device controlled by the ECU, and all actual signals entering the ECU must be replaced by signals from the Hil test system. Because the goal is to test the ECU function, the simulation must be run in real time. The model must respond accurately to the ECU command to test the entire embedded control system. For certain types of signals, it is difficult to reproduce a correct base, because high frequency signals need to be synchronized with the instantaneous position of the crankshaft. Typical examples include cylinder pressure, accelerometers, ion currents, and inlet pressure signals.

There are many Hil systems available on the market at present. The main disadvantage of most systems is the lack of tools to customize the underlying function libraries provided by HIL vendors, which are difficult to access to the underlying (like FPGA) functions, so these systems do not meet customer needs.

The combination of Ni Veristand and NI pxi platform satisfies the needs of users for I/O, computing ability, signal simulation and data analysis, and is completely open and modular. The two key factors that determine the success of this application are the ability to create complex FPGA code using the NI LabVIEW FPGA module and the creation of a custom device to output camshaft, crankshaft, inlet valve, sensor current, and cylinder pressure signals.

The Hil system (Figure 1), presented by the Alma Automotive Company, integrates the following hardware and software components:

A complete engine/vehicle (motorcycle)/driver model developed with PXI real time controller, the step time of the controller is 500µs, the single core CPU load is 20%;

A high-bandwidth signal generator implemented with a custom device used to generate model-based crankshaft, camshaft, inlet, cylinder pressure and ion current signals and to obtain all ECU output instructions, including ignition, injection, H-bridge, and interrupt lights. The custom device is implemented with a 7852R board card.

A custom I/O signal Conditioning board designed and produced by the Alma Automotive company converts the ECU analog output signal to TTL digital signal and, if necessary, enhances the analog output signal of PXI 6723 (variable reluctance signal, VRS).

A custom actuator and sensor fault insertion unit (FIU) designed and manufactured by the Alma Automotive Company and an external junction box that can provide 96-channel signals.

Vehicle simulation mode can be used for open-loop (user driven vehicle) or closed loop simulation (driver follows vehicle speed track). The dynamometer mode can also simulate the running condition of the test-bed. The engine uses multivariable torque graphs to model the output torque, air/fuel ratio and other parameters of the engine. These outputs are sent to custom devices to produce high-frequency signals, such as inlet pressure signals. Engine torque is used to provide vehicle and transmission model, power transmission system components. Engine and vehicle speed are calculated based on engine torque, clutch position, insertion gear, tyre operating condition and actual load on the front and rear wheels.

The driver model controls the steering wheel, brakes, clutches and gears through the torque based control logic, while the dynamometer model calculates the torque provided to keep the engine running at the required speed and load conditions. There is also a heat exchange model to evaluate the coolant temperature of the engine, and the electrical system sub model allows the user to simulate the battery voltage level during the initiator and start-up period.

The core of the system is the NI Veristand custom device plug-in designed by the Alma Automotive Company. The plug-in is an engine I/O subsystem simulator, which can produce a dual-channel vrs/Hall sensor signal, after the signal conditioning peak voltage peak up to 120V, based on the angle of the configurable waveform and 4-channel wheel signal. It also obtains 12 channels of conditioning high voltage ECU excitation signal, 16-channel universal high voltage ECU output signal, such as on/off, frequency and Pwm;8 channel is conditioning to 120V peak Peak range of analog input signal. Figure 2 shows the Setup interface for this custom device. The tooth number of the sensor wheel and the type of the sensor wheel are fully configurable.

Fig. 2 Custom Crankshaft reference signal Generator equipment

The FIU, developed by Alma Automotive, is also based on FPGA, which uses FPGA to handle more than 400 signals that require the operation of switches. The certainty of FPGA allows security features to be set in the system, including user-defined fault timeout, global FIU disabling, and overcurrent monitoring on the fault bus. The FIU operation, which is first closed, is used to prevent ambiguous state in the fault channel through a user configurable load release delay.

FIU, developed by Alma Automotive, can handle 64 channels with a maximum current limit of 2 A and access to four common fault buses. Open-circuit GND, VCC, and Vbatt can be used as power supplies. The feedback information of the switch state can be obtained by 320 LEDs.

The user can connect both the actual load and the emulation load. When the actual load is used, such as the section valve, the simulation system will read the feedback sensor, such as the gas valve potentiometer information and supply model. When using the simulation load, such as the virtual section valve, the feedback signal is generated by the emulator, such as the analog output channel, and sent to the ECU. The switch between the actual load and the simulation load is done by moving the jumper on the external junction box.

The system successfully connected with the target ECU, figure 3 shows a typical NI Veristand interface for Hil testing.

Figure 3 Hil test Control Panel

Users can use the existing methods and the test mode of the platform to focus on verifying all ECU software and hardware features. Easy to use and configure, users can directly reconfigure the system without requesting customer support. NI PXI platform is suitable for integration with third party custom development boards.

It is important that the hardware and software of the Hil test system be updated as needed. Because NI PXI hardware is modular and based on the COTS component, it can be easily upgraded, which ensures that the system will also function in the future and ensure that the technology is in the lead. With its open architecture and easy integration with LabVIEW and other development software, NI Veristand provides the flexibility necessary to meet any challenges that may arise as the test requirements change.