Innovation drivers for electric power-assisted steering

The article is concerned with the analysis, design, and implementation of an electric power-assisted steering (EPAS) system for passenger cars. Key components of the EPAS system include a torque sensor, electric motor, electronic control unit, and control and diagnostic algorithms implemented in software. The heart of a typical EPAS system consists of a three-phase motor and its associated power electronics drive circuitry. The main functional blocks of the electrical drive system are the vehicle power supply (battery and harness), a filter circuit, a three-phase inverter bridge, and the motor windings. The single-unit integrated design of EPAS can be packaged on the steering column, steering rack, or pinion. The technical and commercial benefits of EPAS are compared with existing technologies. Detailed examples that link control and systems analysis to innovative areas of the design is also focused upon.