The Sensor - Fiat TIPO Bedienungsanleitung

The engine current uptake ranges from 1 A to 80 A. The maximum current uptake occurs when
evasive manoeuvres are made with high steering wheel rotation speeds.
The motor has been designed to provide the torque required. In other words it has been designed to
help the user according to the effort required at the steering wheel.
The wheels offer different resistance to the steering column depending on whether they are on ice or
asphalt, for example.
As a result the motor provides torque in accordance with that required.
The Electric Steering Node controls every single (three phase) winding by controlling the current.
As the rotor has permanent magnets, it tends to move towards and reach the centre of the magnetic
field.
The Electric Steering Node controls the position of the rotor via the signals sent to it by the Hall-effect
semiconductors.
The exact position of the rotor is used by the control unit to drive the current (activation) through the
relevant coils and to maintain the engine torque.
The activation of the individual coil is carried out using the FET bridge illustrated above with a working
frequency of 18 kHz using the PWM (Pulse Width Modulation) method for each individual coil.
The diagram illustrates how, when the current is supplied to one winding, it is requested in another,
whilst in the third winding no current flows through. On switching, the current flows passing through
the coils change.
The synchronised, self-switching motor always operates at the required torque determined by the
force exerted by the user on the steering wheel and, as the torque request increases, the value of the
current passing through the windings increases proportionally: this value will be around zero when no
torque is requested from the engine.

The sensor

The sensor that measures torque and position is fitted on a single casing secured to the geared motor
casting, whilst the input and output shafts are free to rotate, driving the moving measurement parts.
As stated previously, the sensor has two functions: it measures the torque and the position of the
output shaft.
When measuring the torque, it can be compared to a potentiometer where the resistive support is
secured to the output shaft and the cursor is secured to the input shaft. The twisting moment on the
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FIAT TIPO -6- 0.0
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