KangYoung Lee - Research Engineer, Control System Verification Team, Hyundai Autron Co., Ltd
Beomseop Kim - Part Leader, Control System Verification Team, Hyundai Autron Co., Ltd.
Cars in the past were equipped with simple electrical and electronic devices, such as an ignition and battery recharger. The scope of application for electronic devices has expanded, however. Today, more and more electronic devices control the overall systems of a car, including the engine, chassis, and other convenience features. New electric and electronic control technologies continue to pour into the market. These new devices have led to the development of a next-generation device control architecture structure equipped with integrated body unit (IBU), integrated central control unit (ICU), and driver area unit (DAU). These integrate with the previous convenience management system architecture that includes body control module (BCM), SMartKey (SMK), smart junction box (SJB), driver door module (DDM), and tire pressure monitoring system (TPMS). The emergence of new devices has created a demand to verify the reliability of the control of the newly developed next-generation architecture. However, the conventional hardware-in-the-loop (HIL) system is designed to verify the ability of the previous architecture’s control capabilities, and cannot verify the next-generation architecture.
The development discussed here pertains to a new improved version of HIL system from the conventional BCM verification equipment and for the verification of the automation of the next-generation architecture controller, namely the IBU controller integrated with some BCM, SMK, and TPMS capabilities.
Limits of the Conventional HIL System
The conventional HIL system was developed to verify single BCM units. It can simulate high/low active-type switch through digital output, simulate multifunction switch and analog sensors through analog output, measure the signal emitted by the controller through analog input, and simulate the CAN communication environment through vector equipment. However, it cannot verify an IBU due to lack of SMK antenna searching environment and RF transmission environment for TPMS.
Developing and Linking an SMK Evaluation Environment
To simulate the antennas in Interior 1, Interior 2, Driver Side, Assist Side, Trunk, and Bumper, we designed a board to contain relay circuits in each antenna line and a smart key(fob) in antenna search area. The relay circuit control of the digital output can connect the IBU LF signal line of the desired area with the circuit of the antenna line. This means the LF signal can reach the antenna and search for a fob. A fob within an antenna’s search area responds with RF, completing the controller's fob search. In other words, all of the circuits except the desired one is open and unable to receive any signal, and only the connected antenna can perform a fob search, which helps the controller recognize the location of the fob.
We developed the new system so its digital output could control the antenna circuit board’s relays, which makes it possible to link the new system easily with conventional HIL systems by adding more circuit boards and assigning additional digital outputs without additional software development.
To create a verification environment for a tire pressure monitoring system (TPMS), we need the new system to count the wheel pulse continuously in accordance with the vehicle speed (wheel speed). For this, we developed a program for TPMS to operate continuously as a background process.
The FPGA board keeps counting the wheel pulse in relation to the vehicle speed, and transmits RF send timing to RFSG as interrupt requests in accordance with the tooth count. Upon receiving a request, RFSG sends an RF signal to IBU consisting of various information such as TPMS manufacturer, ID, pressure, and temperature. The IBU determines whether the air pressure of the tire is normal or abnormal and sends a warning display CAN signal to the cluster.
In addition, we developed the system to allow wheel pulse count and RF transmission to operate in accordance with the vehicle speed (wheel speed) to create an environment for automatic position learning to determine if a tire is in an abnormal position, and for automatic learning capability that determines the validity of RF signals. Users can run this program individually and control it through TCP/IP when linked with an automation program. Figure 2 shows the program’s GUI.
Software and Hardware
The software for the new HIL system contains a main program written in C# for the test case and result handling and equipment management. The program calls out VIs as needed in accordance with each test case’s test step and returns the result. Called VIs are the plug-in type, which we can easily develop and operate as long as the interface fits the VIs that act as a parent. Some of the types of plug-in VIs include DAQ.vi for digital I/O and analog I/O simulation and measurement, CAN.vi for CAN simulation and measurement, TPMS.vi for the simulation of RF signal for the evaluation of TPMS, Serial.vi for RS232 communication with power supply and controller, and GPIB.vi to control the digital multimeter. We can use these VIs to control different devices such as measurement hardware and lights. Figure 4 shows the structure.
The HIL system includes two racks connected with the MXI communication method, which we can thus control as one PXI. They come with a signal conditioning board developed to accommodate a car controller. Figure 5 shows the structure of the racks.
Equipment Operation Test Result
Once we finished developing the new HIL system, we created an evaluation environment to test the new system with an IBU that Hyundai-Kia Motors is creating. We used 15,000 cases that were developed based on the company’s specifications to perform the verification. The test took 40 hours. After the verification, the HIL system discovered the same eight flaws that were discovered through a manual verification. We got the same result when the new system was tested again with an updated IBU software.
Effects of HIL System Development and Future Plans
We developed a new HIL system with SMK and TPMS capabilities, on top of the conventional BCM single-unit evaluation capability, so we could evaluate the IBU next-generation architecture controller. We conducted two automated tests on the new HIL system which confirmed its reliability and level of completion.
We have seen benefits since developing this new system. Once we delivered the HIL system to Hyundai-Kia Motors, together with the test cases designed based on their specification requirements, the system generated about $94million in sales. Additionally, we applied hardware and software standardization to the HIL system, which reduced the development period of an HIL system from six months to only one month. This is the period required for the purchase and creation of actual hardware.
The HIL system may not only facilitate increased development quality through repeated and malignant tests that were impossible through manual tests, but may shorten the development period of new vehicles by drastically reducing the time required for verification during development of the vehicle controller.
The paradigm for automobiles is now shifting from a mere means of transportation to a smart living space. This shift in paradigm also entails diverse customer demands. New features such as an advanced driver assistance system (ADAS), automatic driving, connected cars, and augmented reality are taking the stage. These features come to life through cooperative control with other controllers. We now require stronger system-level verification as this type of cooperative control helps each system’s influence expand into other systems’ territories. In other words, we now need verifications on system environments, not on single unit environments. We are scheduled in the future to use this technology and NI products that are easily expandable to develop a new HIL system that can verify not only a single controller unit but an integrated verification of electronic control systems.
Research Engineer, Control System Verification Team, Hyundai Autron Co., Ltd