How The Sensor Resolver Works

A sensor resolver is an electromechanical device widely used in various applications to measure the angle of a rotating shaft. It functions similarly to a transformer, with its primary role being to convert the mechanical angle of a rotor into an electrical signal that can be interpreted by a control system. Here's a basic outline of how a sensor resolver works:

1. Structure: A resolver typically consists of a rotor and a stator. The rotor is connected to the rotating shaft whose angle is to be measured. The stator surrounds the rotor and usually contains windings.

2. Excitation: The primary winding on the stator is excited with an AC signal, commonly referred to as the reference signal. This signal is typically a high-frequency sine wave.

3. Induction: As the rotor turns, it changes the magnetic coupling between itself and the stator's windings. This change affects the electromagnetic field within the device.

4. Output Signals: The resolver has two secondary windings on the stator, oriented perpendicularly to each other. As the rotor rotates, the varying magnetic field induces voltages in these secondary windings. These voltages vary sinusoidally, with their amplitude and phase dependent on the angle of the rotor.

5. Signal Conversion: The voltages from the secondary windings are then processed to calculate the angle of the rotor. This is done by comparing the phase of the output signals to the phase of the reference input signal. The resulting phase difference is directly proportional to the mechanical angle of the rotor.

6. Angle Determination: By using trigonometric relationships (sine and cosine functions related to the angle), the exact angular position of the rotor can be calculated from the phase differences.

Resolvers are prized for their durability and accuracy, making them ideal for harsh environments or applications where precise angular measurements are crucial, such as in aerospace, automotive, and industrial robotics. They are also favored for their ability to function at high temperatures and under mechanical stress, unlike some electronic sensors.