Users Report Vol. 118

Electronic Control Components Division
Denso Corporation

Committed to Realization of Safe and Secure Mobility Society in Consideration of New Needs Such as Automated Driving
UC-win/Road to be Utilized for Developing a Simulator that Allows Bodily Sensation of Performance of 2-Drive EPS

Denso Corporation
Location: Kariya-shi, Aichi
Services: Development and assessment of
electronic components that compose EPS in
DENSO Corporation, which provides a wide
range of systems, products and services
from the automotive area as
its core to industrial and consumer products

Mr. Naoki Nakane, Director of
Electric Control Eng. Planning
Department, Electronic Control
Components Division
Mr. Kazumi Arimoto, Manager of
Technology Section 4, Electric
Control Engineering Department
Mr. Hideki Amakusa, Project
Assistant Manager, Electric Control
Engineering Department

"EPS (Electric Power Steering), which is a mechanism to allow a vehicle to turn a corner, is a function to make the wheel operation lighter. The 2-Drive EPS we have developed offers safe and secure steering that prepares against an emergency. When it came to how to make this appeal to potential users widely, we thought of getting them to feel its bodily sensations using a simulator. Then we got into contacts with Forum8."

Power steering supports the driver's steering action by reducing the effort required to turn the steering wheel. Mounted in almost every vehicle, the mainstream of this equipment is EPS that directly uses the electric motor power for assisting steerage in recent years, with its advantage of realizing low fuel consumption compared with hydraulic systems. On the other hand, it is required for EPS to have high reliability due to the important function of steering; moreover, even when a problem occurs in EPS, it needs to have a function to maintain assistance for a certain period of time (fail-safe operation). In order to respond to such needs, DENSO Corporation developed 2-Drive EPS for the first time in the world. Mr. Naoki Nakane, Director of Electric Control Eng. Planning Department, Electronic Control Components Division, DENSO Corporation remembers that they hit upon an idea of using a simulator to allow their technological strength to get recognized widely as well as its product characteristics.

Our user this issue picks up is DENSO Corporation, which boasts accumulated technologies over years with the automotive products as its core, and provision of advanced and diversified systems, products, and services for automotive, industrial and consumer products based on its technologies. We specially focus on people in charge of planning, development and assessment from a technological point of view in Electronic Control Components Division that takes responsibility of developing products that compose 2-Drive EPS, as part of aiming at ensuring safety and security, and achieving a society with highly qualified mobility of the next generation.

Before 2-Drive EPS shifted into mass production in 2015, DENSO explored effective approaches to have the advantages of outcome of the Company's development to be widely recognized. In 2013, they developed a simple simulator using "UC-win/Road", FORUM8's three-dimensional (3D) real-time VR, which had already been introduced in other division. They tested it by having a limited number of customers to experience it, getting a positive impression as a result. Consequently, they introduced UC-win/Road on a full scale in the following year (2014). Since then, they upgrade functions and scenario of the simulator every year and use it effectively in domestic and international exhibitions and so on.

 Diverse Business Expansion and the Roles of Division

DENSO Corporation spun off from Toyota Motor Corporation to be independent in 1949. It was founded as Nippondenso Co., Ltd., a manufacturer of automotive-electric components. Since then, the Company has been committed to research and development of technology and products to pursue "world-first", improving the assessment system for realizing high qualification, and fostering diverse human resources. Above all, they have expanded their business contents to the following areas: 1) Automotive business, which covers a wide range of products and systems with main categories of powertrain control-, electronic-, thermal-, and information & safety systems, and small motors as the core; 2) Consumer products including housing facilities with its core such as heat-pump water heaters and air conditioners, 3) Industrial products such as industrial robots, factory automation products, and automatic identification products; and 4) New business fields to apply the technologies developed in automotive products. With these changes as the backdrop, the Company altered its name as it is now in 1996.

On the other hand, DENSO has business units to deal with individual product areas, and several business groups, each of which comprises 3 or 4 business units by category. One of them is the Information & Safety Systems Business Group. Aiming at realization of highly qualified mobility society without traffic accidents, the Group targets development of technologies for ensuring confidence and safety including automated driving technology.

Positioned as a semi-business unit that forms the above Business Group, Electronic Control Components Division takes charge of technological development on electric and electronic products that compose EPS. Within the Division are Departments specializing in particular roles by function. Among them, Electric Control Engineering Planning Department, of which Director is Mr. Nakane, not only performs product development of the concerned area but also examines business strategy in consideration of the future technological trend.

In contrast, Electric Control Engineering Department performs detailed designing for mass-production of the developed products etc. This time, Mr. Kazumi Arimoto, Manager of Technology Section 4, Electric Control Engineering Department took charge of constructing a simulator for feeling bodily sensations of 2-Drive EPS. Section 4 assessed the developed products from various angles through diverse EMC tests and environmental tests, as a preceding step before mass-producing them. In addition, Mr. Hideki Amakusa, Project Assistant Manager who took part in developing the scenario and simulator using UC-win/Road, is working on the product tests using devices that imitate actual cars in Technology Section 4.

DENSO is expanding as a global automotive component manufacturer, currently having about 200 group companies in 38 countries in the world in addition to its domestic bases, with about 150,000 employees altogether.

"2-Drive EPS" exhibited in DENSO Gallery

 Developed 2-Drive EPS to Clear Hurdles by Making the Best Use of Advantages of EPS

Mr. Nakane begins by saying, "The basic EPS system contains steps from operating the steering wheel to moving the tires." According to him, the mission of Electronic Control Components Division includes three elements: 1) Based on signals such as of a torque sensor, 2) ECU (Electronic Control Unit) calculates the optimum motor output (assist force), and 3) Drives the motor based on the command value from ECU.

In the latter half of the 1980's, since EPS was mounted for the first time in light vehicles with small engine output (Kei car), EPS has been replacing hydraulic power steering that was the mainstream gradually. Since oil pressure is generated using engine output, it is always generated while turning on the engine. It takes piping space as well as produces waste oil. In contrast, EPS is excellent in mountability and contributes to improvement in fuel efficiency since it assists electrically only when needed. It also has an advantage of operating a wheel lightly during engine stop. These have made EPS spread rapidly since about 2000.

Just as similar to the other electric products mounted in the vehicle, EPS is composed of a large number of electronic components. Though very rare, the likelihood that a problem occurs is not zero. Moreover, if there is anything unusual to power steering, it may happen that the steering wheel rapidly becomes hard to turn sharply, leading to a traffic accident. Therefore, it has been urged to take some sort of countermeasures. It is the above-mentioned 2-Drive EPS that DENSO developed as its solution for the first time in the world. This has 2 independent drives of the electronic circuit and coil of the motor. The assist force is divided into them to support each other. If a fault should occur to one of the drives, the other drive instantly continues to assist the function of turning a corner. It is so designed to maintain traveling that is safe, secure, and smooth.

Click to enlarge the image. Click to enlarge the image.
1. Traveling in an urban area with a traditional
EPS (driving smoothly with light steering wheel)
2. A problem occurs with traditional EPS
(hard to drive with heavy wheel)
Click to enlarge the image. Click to enlarge the image.
3. A problem occurs with 2-Drive EPS (driving
just as usual with light wheel)
4. A problem occurs with 2-Drive EPS during
automated driving
(capable of maintaining automated driving)
VR images of the EPS drive simulator: appealing the product value of 2-Drive EPS using bodily
sensation of a series of simulation scenes

  Process of Developing DS Capable of Bodily Sensing the Effect of 2-Drive EPS

"No matter how much we say in words that (a vehicle mounting 2-Drive EPS) will be safe, it is hard to communicate the pleasure (brought about by that) (to other people) without actually experiencing it."

Though they commercialized 2-Drive EPS in advance, partly because their competitors seemed to follow them, they wanted to have its advantages to be recognized early on widely. In addition, as for EPS, they also wanted to release the restrictions due to its business form of "Tier 2" (subcontractors) to improve a degree of recognition of the user about their technological capacity. Especially, when a problem occurs with general EPS, it might be possible to understand theoretically that steering becomes heavy, but it is hard to imagine how much and what kind of influence it has on driving. In searching for effective solutions for such needs and problems, they thought that the best way was to allow people to experience it by themselves. However, using actual cars was risky, and consequently the place and number of people for the test drive had to be limited. Thus, in order to allow as many as people to experience 2-Drive EPS, they hit upon development of EPS Drive Simulator (DS), says Mr. Arimoto.

In 2013, using UC-win/Road that was used in other section within the company for other purpose, they represented a simple zigzag road with VR by themselves. Disassembling commercial game machines to utilize the parts, they linked the steering wheel mechanism (hardware) with feel close to an actual car with VR data. Having test subjects to drive it, they built up an object that enabled the driver to bodily feel what would happen if there should be any fault to 2-Drive EPS. In their private booth installed at "Tokyo Motor Show 2013" in that year, they had the DS tried by their customers who had business relations with them. It was favorably evaluated more than expected.

Following this, the next year, in 2014, they introduced UC-win/Road on a full scale. Mr. Arimoto and others prepared a scenario, and created VR data for the scene of traveling along an actual townscape. By linking the accelerator, brake, control operation of EPS and so on with cables and operating it "while exchanging data in an analogue way," (by Mr. Arimoto), they produced DS in-house, which enabled bodily feeling to tell the difference between usual EPS and 2-Drive EPS when a problem occurs. It was used in new product exhibition within the Company and so on.

Since 2015, they introduced CAN (Controller Area Network), changing the form to that of exchanging different kinds of data on the sides of UC-win/Road and DS. As a result, the development period was shortened and specification change became easier. Moreover, linking diverse information caused variations of simulation to expand. In addition, in the same year, mass-production of 2-Drive EPS started. It became possible to open DS to public on the center stage. The DS was exhibited in the motor shows held at Tokyo as well as Frankfurt, German. Along with this, a version with English guidance for international events was created, in which the car travel on the right lane along townscapes of Europe and United States of America.

Since then, they upgraded the VR version every year with Mr. Amakusa as the core person by trial and error as to what kind of scenario could allow the user to easily understand it. In 2016, they prepared a scenario on the assumption that some faults should occur to EPS while traveling on an expressway by automated driving. Its outcome was made open to public in The World Congress on Intelligent Transport Systems 2016 Melbourne.

Further this year, they created VR by mixing the scenes of traveling on general roads in urban areas and on expressways. The DS mounting the latest version was exhibited in the Automotive Engineering Exposition in Yokohama (in May) and Nagoya (in June).

EPS Drive simulator exhibited in an exhibition

 Evaluation on EPS DS, and Expectation Towards New Possibilities

"The manufactures of B to B (business-to-business), we have few opportunities of hearing real voices of end users." However, by obtaining direct reaction from the test subjects who experienced bodily sensations of the DS, the motivation of the concerned people should get higher, leading to quality improvement. In addition, since Mr. Nakane had been posted overseas until last year and took the guiding role in the Frankfurt Motor Show 2015, he thought that the DS should not only be understood by general users with ease but also give an impact on their domestic and international competitors.

Mr. Amakusa, who saw the images created with UC-win/Road for the first time in the 2014 version of their DS, remembers that his first impression was like "how amazing the screen images are!" Since then, images made progressions every year along with version upgrades. Relative to its backdrop, he mentions the full support by FORUM8, with the viewpoint of him working on producing the DS since 2016.

On the other hand, partly because there are some restrictions to using actual vehicles only for the test in the process of assessing the products, they are examining a shift to assessment using simulation. To realize this, it is critical for the DS itself to realize reality in various terms more highly. Mr. Arimoto expects new possibilities for utilizing the DS in the product assessment process in the future, in consideration of response to automated driving and advanced driving support, connected cars, electric vehicles etc., which are hot topics in the automotive product area.

Written by Takashi Ikeno
(Up&Coming '17 Summer issue)