JSAE Exposition 2017: Advances in electric power steering

Development trends of coordinated control for autonomous driving and fail-safe operation

2017/07/03

Summary

JSAE
Exposition 2017
JSAE Exposition 2017   The sight of the whole venue

  Major suppliers displayed autonomous driving support systems at the JSAE Automotive Engineering Exposition 2017 (organized by Society of Automotive Engineers of Japan, Inc.) held in May, 2017. The exhibitions showcased cooperative controls for the various systems vehicles are constituted of.

  As the development of autonomous driving systems is accelerating, further improvement in the safety function of electric power steering (EPS) is becoming essential. Whereas traditional power steering only assisted manual steering effort, functions for controlling the steering angle vehicle behavior are being added, and there is growing demand for other new features including precision control, reliability, and response in the case of failure.

  For advanced driver assistance systems (ADASs) like lane departure warning and lane keep assist, cooperative control with functions including the steering, drive, and brake systems is becoming increasingly important. At the same time, advances continue to be made for Steer-by-Wire technology that replaces mechanical regulation for electric regulation in steering operation. Meanwhile, as development of advanced ADAS and autonomous driving technology progresses, system failures are becoming a greater area of concern than before, as control and assist becomes ineffective due to electrical short-circuits, errors, or system failures. There is a possibility for enormous damage to occur if an electrical error occurs when the EPS is operating to avoid danger.

  Fail-safe operation technology is beginning to be introduced to cope with problems and malfunctions that accompany the high performance and complexity of such control systems. EPS are equipped with an electromechanical control system that is incorporates an ECU and a motor in the steering mechanism. A redundant, dual system design for both ECUs and motors makes it possible to maintain a vehicle's movement and stop it safely even if one of the systems fails.

  At this exhibition, Bosch and Denso exhibited EPSs with fail-safe operation and used panels and demo units to illustrate the safety features of its system, which is composed of a dual circuit ECU and motor. NSK also exhibited an EPS with a redundant design for the motor, ECU, and torque sensor. NTN showcased a mechanical clutch unit (MCU) for next-generation steering that has been adopted for the Nissan Skyline's Steer-by-Wire system. JTEKT presented an ADAS-compliant roadmap for Steer-by-Wire systems and an auxiliary power supply system that has enhanced redundancy and power backup and supports equipping EPS in large-size vehicles. SHOWA had a display showing the cooperative control of its power steering and suspension.

Related reports:
Analysis Report by Component : Power Steering (Japanese Market)
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Analysis Report by Component : Brake (Japanese Market)
Analysis report: Brakes (E.U. and U.S. market)