TATA Motors Builds HIL Test System for Hybrid Vehicle Simulation Using NI Tools

About Tata Motors

TATA Motors is India’s largest automobile company. It is the leader in commercial vehicles in each segment and among the top in passenger vehicles, with award-winning products in the compact, midsize car, and utility vehicle segments. It is also the world’s fifth largest truck manufacturer and fourth largest bus manufacturer.

As part of the Advanced Integration Team for TATA Motors, our responsibility is to validate the integration of major electronic components in a vehicle, such as electronic control units (ECUs) and instrument clusters. This responsibility also includes responding to and resolving reported field failures and providing feedback to the respective teams. In a broader perspective, the Advanced Integration Team serves as a bridge between the design phase of vehicle development and final deployment of the vehicle.

Application Specifics

The objective of our project was to build a universal test setup that could easily be customized to test any ECU with minimal effort. The system also needed to be scalable to cater to multiple ECUs simultaneously and flexible enough to interact with different ECUs on occasion.

For one of the upcoming parallel hybrid vehicles, we decided to integrate all the ECUs and electronic components in a lab environment and validate the integration using a hardware-in-the-loop (HIL) test. We wanted to cater to all probable field scenarios and rectify issues before assembling the first physical prototype. The results of the integration test could significantly help with the selection of ECU software and the evaluation of options from multiple vendors with multiple functionalities.

When we initially conceptualized the vehicle design, we isolated four major ECU components and devised the test plan per the requirements. At that point, we decided on a non-NI HIL system to meet our test needs. We later procured that system. During the same period, we were using a PXI system from NI to perform HIL testing of one particular ECU for a different vehicle, and we really liked the modularity of the PXI technology. We considered the benefits of the PXI platform and invested in a real-time PXI system from NI that we could use for our future requirements.

As the vehicle design evolved over the next few months, the number of major ECUs increased from four to six. We were short channels in the non-NI HIL system, which was tailor-made for our initial requirement of four ECUs. At that point, we migrated to the real-time NI PXI system and started working with NI VeriStand software.

We added a few modules to meet our channel requirements. By spending some time with NI VeriStand, we were able to build the test software for six ECUs in less than two months.

System Architecture

Multiple plant models simultaneously executed within the NI VeriStand engine, which communicated with the respective ECUs through physical I/O over a controller area network (CAN) network. The ECUs in turn communicated with each other through a shared CAN network. We integrated some physical components with the setup, including the exhaust gas recirculation valve, motors, and electrical loads.

In most cases, the model I/O mapped to the hardware I/O. However, certain non-standard signals, such as the cam and crank, required in-line processing. W e used the NI LabVIEW FPGA Module and NI reconfigurable I/O (RIO) technology to integrate high-speed data capture and signal processing for these signals into NI VeriStand, which offered us immense flexibility.

During the test, we simulated drive conditions and monitored the CAN network for error frames and diagnostic messages from various ECUs. These frames served as an indicator of the quality of integration and helped us identify potential failures. We also isolated ECU firmware issues. We sent feedback from these tests to the design team and, in some cases, to component suppliers.

Key Benefits

The HIL test system based on NI products helped us address concerns with our previous setup and also enhanced our productivity in many ways. Some of the main benefits include:

• Scalability: We needed scalable test systems for the projects assigned to our team, and PXI helped us achieve this. System channel requirements could increase with time, making a tailor-made solution a hindrance. The ability to easily add modules to a PXI chassis made the upgrade process quite simple, and we were able to future-proof our system to a great extent.
• Flexibility: We wanted to create a system that we could reuse to test ECUs for other vehicle models in the future. Our test system included generic hardware modules and customizable software for flexibility. We can use the same setup for a different set of ECUs with just two changes: building a new NI VeriStand project with new plant models and rewiring the physical connections with the new set of ECUs.
• Productivity: There were times when we did not have the physical ECUs for testing. In those cases, we could use the ECU simulation model instead and map the plant model. The ease of mapping hardware I/O with the model I/O and parameters greatly increased productivity. I solely worked on the NI VeriStand project and was able to build the software in less than a month.
• Hardware Quality: Compared to our alternate system, the PXI hardware was superior in terms of quality and reliability. Also, the option to program FPGAs helped us achieve near-perfect system responses.

Why We Choose the NI HIL Platform

With NI modular hardware and extensible software, we built a future-proof, reliable, and adaptable HIL test system. The ability to customize the system on our own made us confident in the test results and continued support from NI helped us achieve our objectives faster.

Author Information:

Sanjay Mane
TATA Motors