two-motor steer-by-wire steering system prototypes

Seiko has produced a "Double Link Arm Steering Steering System (DPASS)" that is operated by the direct rotation of the front wheel steering rods by the rotational force of the two motors, and at the 40th Tokyo Motor Show (October 2007) From the 27th to the 11th of November, the exhibition was held. The system combines Seiko's Multi-sensing Hub Unit with two motors to contribute to increased active safety.

The multi-sensor hub developed by the company can detect 3-way load from the road surface (lateral force: force applied to the tire during cornering, front-rear force: force applied to the tire during acceleration and deceleration, up and down force: tire contact with the road surface The force can be controlled to the optimum state even if the road conditions change, so that the vehicle can be driven in the direction the driver wants.

Most of the original steer-by-wire systems used a conventional rack-driven EPS (electric power steering wheel) drive mechanism. The DPASS of this trial is different, and the left and right wheels are separately operated by arms (steering arms) that protrude at right angles to the motor rotating shaft. In this way, even if the steering shaft is not mentioned, even the rack and pinion can be omitted, so that the mechanism can be greatly simplified and the space efficiency can be improved compared with the original. Thanks to the two motors, there is also a fault protection function, which can be operated by another motor when one of the motors fails.

JTEKT, which previously exhibited the largest number of wire-steering steering systems among bearing manufacturers, also exhibited a wire-steering steering system using a rack-driven EPS mechanism. It seems that the development competition of the wire-controlled steering system will become increasingly fierce in the future.