Electric Power Steering
The Power Steering Control Module (PSCM) is activated when the control module receives 15 supply via the ignition. This is to diagnose certain functions and at the same time prepare to start the electric motor. When the motor is then started, the control module immediately activates the system's electric motor so that the power steering is activated.
The following is measured when the driver turns the wheel:
- steering angle
- the vehicle speed
- engine status (engine running)
- power supply mode.
These input signals, together with the internal signals (electric motor speed, temperature in the control module, power consumption of the electric motor etc) are used by the control module to control and diagnose the electric power steering. This gives optimal power steering adaptation.
The control module controls the power consumption of the electric motor using the internal power stage. For efficient control of the electric motor, a pulse width modulated supply is used. By controlling the pulse ratio, the control module is able to regulate the output of the electric motor and therefore the speed which indirectly adjusts the torque in the power steering system. Principally the control module continuously monitors the following:
- Power consumption for electric motor
- RPM for the electric motor
- Temperature in the control module
- Friction in the steering gear
This means that the system is regulated constantly so that the correct torque is used. The functionality of the system can also be diagnosed efficiently.