The need for in-vehicle microcontrollers is growing as automobiles become more computerized. Electronic control technology using these microcontrollers generates powerful solutions to address various challenges the automobile industry currently faces, including safety improvements, comfort enhancements, and environmental load reductions. Additionally, as the proliferation of next-generation automobiles using electrical power sources, such as EVs or HEVs, gains widespread momentum, those working on in-vehicle system development are seeking out more advanced electronic control technologies. This is leading to the demand for higher level in-vehicle microcontrollers. To quickly meet these market needs, many semiconductor manufacturers are developing in-vehicle control systems to adapt to cutting-edge technology. Renesas Electronics is leading this movement. Renesas Electronics develops strategic products to supply microcontrollers for in-vehicle device makers in a timely manner and is opening up the in-vehicle microcontroller market.
“We would like to be one step ahead of our users—the automobile and in-vehicle device manufacturers,” said Hideki Kagawa, Chief Engineer in the Automobile System Management and Automobile Advanced System Technology Departments at Renesas Electronics. “We unearth the problems our users will face before they get there and would like to be the first to offer them solutions. To make this happen, it would be beneficial for automobile or in-vehicle device manufacturers to have a testing environment for microcontroller-mounted devices. However, automobile systems are comprised of sophisticated components, and it’s not easy for a microcontroller supplier to have the exact same development environment as its customers.”
Renesas Electronics developed the HILS system, using LabVIEW software and a PXI modular system (Figure 1), to solve this problem.
Running a Maximum of 16 Virtual CPUs
Renesas Electronics deployed this system based on NI hardware and software because the company was already using real-time motor controls for new technology verification for its RH850 family of automotive microcontrollers. This technology is used for motor control, which is the power source of EVs and HEVs. Most motor control microcontrollers have a dedicated piece of motor control hardware mounted on the fringe of the CPU to achieve precise control.
“If we can suppress power consumption while increasing performance by introducing virtual CPU technology, we can actualize versatile hardware that can respond to all sorts of motor control requests just through software changes alone,” said Kagawa.
Virtual CPU technology uses one physical CPU as multiple virtual CPUs. By virtualizing the CPU and performing parallel data processing, the CPU is more streamlined and performance can be enhanced without an unnecessary increase in power consumption.
Developers use a multicore architecture with four mounted CPU cores, in which each physical CPU runs as four virtual CPUs (Figure 2). Thus, they can perform parallel processing using up to 16 virtual CPUs. The objective is to thoroughly optimize this architecture for advanced real-time control through feedback from the motor controls with sophisticated real-time capabilities.
“To optimize the microcontroller’s architecture, we need to control actual motors like our users do to identify what functionalities and capabilities are required. That’s why we thought the HILS system was necessary,” said Kagawa.
Hagiwara Electric stepped forward to develop the HILS system that Renesas Electronics needed. Hagiwara is a distributor of the company’s products and is experienced with prototype development of built-in microcontroller systems for automobiles. In addition to selling electric devices and IT equipment, Hagiwara Electric is also a National Instruments Alliance Partner.
A Compact and Affordable HILS System
A HILS system validates an actual device by interlocking it with a virtual model and reproducing the operating conditions of the entire system. Hagiwara Electric provided a full-vehicle HILS system (Figure 3) that creates a reproduction of the full array of automotive movements using virtual models. This system powers the states of various systems used in an automobile while the car is in motion to be reproduced. Thus, users can now validate the behavior of in-vehicle electronic systems such as electric control units (ECUs) when the vehicle is in motion without an actual car. Many automobile manufacturers are already incorporating such systems into the development of their ECUs.
Motor Model Implemented on the FPGA
This full-vehicle HILS system offers virtual models of vehicles equipped with a hybrid engine that is a combination of a diesel engine and a motor driving system. The system combines the technology from many companies including Hagiwara Electric, National Instruments Japan, Neorium Technology, and Mac Systems.
A vehicle model developed by Neorium Technology, a company that sells automotive simulation software and develops simulation systems, and a motor model jointly developed by National Instruments Japan and JSOL Corporation, are implemented on the NI PXI modular hardware.
The hardware combines the NI PXIe-1071 chassis, which contains a total of three components—the NI PXIe-8133 controller, the NI PXI-7841R FPGA module, and the NI PXI-7854R FPGA module. The monitor connected to the controller displays the measured data related to the vehicle and motor control output conditions.
The vehicle modes and motor models are implemented on the controller and the NI PXI-7854R module, respectively. Developers achieved high accuracy in a simulation using dedicated hardware with FPGA technology for high-speed processing of the motor models. Mac Systems, a company experienced in measurements and test system development, integrated the hardware and software for the system.
Once the system was done, Hagiwara Electric made some tweaks to optimize it to meet the requirements.
Using the FPGA, developers at Renesas Electronics made a prototype of a microcontroller with a new architecture. They incorporated this on an evaluation board and installed a multicore real-time OS from eSOL Co. Ltd. on top of it, which helped the motor control application get up and running. They connected this evaluation board to the HILS system via an extension I/O board and interface boxes to evaluate the new motor control technology.
“We will be able to produce a value-added in-vehicle microcontroller by leveraging a technology developed using this full-vehicle HILS system. Please look forward to our future product offerings,” said Kagawa.
The LabVIEW software platform encompasses a wide range of system development techniques, from real-time OS and Windows-based application development to FPGA development. The NI PXI platform is a flexible modular system that can be configured to include all the functionalities needed. With a graphical system development platform combining these two components, even unprecedented systems can be built at a much faster pace. It is also possible to rapidly construct a development environment or system that meets continuously emerging standards. Many engineers are under pressure to develop revolutionary and value-added technology and products. Incorporating an advanced development platform such as this one will help speed things up.
Article first published on "Tech-On!”. Reproduced with the permission of Nikkei Business Publications, Inc.
Renesas Electronics Corporation