Electrical assisted power steering

Electromechanical power steering systems are increasingly replacing the hydraulic steering systems. On the  one hand, they form the basis for central assistance functions. On the other hand energy-efficient systems must be used to reduce the electrical power consumption of a modern vehicle.

The main advantages of the electromechanical power steering system in contrast to the hydraulic steering system are:

• Weight savings by eliminating the hydraulic system
• Reduced noise
• Improved control characteristics
• Simplified installation
• Simplified maintenance
• Reduced energy consumption

The electromechanical power steering system generates when needed - and only then - high steering assist forces from the 12-V power supply. For this purpose, a permanent-magnet DC shunt motor is used, which is located directly on the steering column. As an input signal the steering torque sensor records the torque applied by the driver on the steering wheel. For this input value a driving situation-oriented steering power is generated taking other environment variables into account, too.