Gyro sensors - What is Gyro Sensors?

Gyro sensors
Gyro Sensor Types
Vibration Gyro Sensors
How Angular Velocity Sensing Works in Vibration Gyro Sensors
Gyro Sensor Applications
Sample applications

Gyro sensors

Gyro sensors, also known as angular rate sensors or angular velocity sensors, are devices that sense angular velocity.

Angular velocity

In simple terms, angular velocity is the change in rotational angle per unit of time.
Angular velocity is generally expressed in deg/s (degrees per second).

Gyro Sensor Types

Gyro sensors come in a variety of types. Here, different types are plotted by size and performance.

In recent years vibration gyro sensors have found their way into mirrorless / SLR cameras, vehicle electronic stability control (anti-skid) systems and among other things.

Epson Gyro products

Vibration Gyro Sensors

Vibration gyro sensors sense angular velocity from the Coriolis force applied to a vibrating element. For this reason, the accuracy with which angular velocity is measured differs significantly depending on element material and structural differences. Here, we briefly describe the main types of elements used in vibration gyro sensors.

Types of elements used in vibration gyro sensors

Vibration gyro sensor manufacturers are using a variety of materials and structures in an effort to devise compact, high-accuracy gyro sensors that have good characteristics, including:
- scale factor
- temperature-frequency coefficient
- compact size
- shock resistance
- stability
- noise characteristics

	Material	Sample Structure
Piezoelectric transducer	Crystal
Silicon transducer	Silicon	Si MEMS NOTE: Every company uses a different structure.

Piezoelectric transducer
Material	Sample Structure
Crystal

Silicon transducer
Material	Sample Structure
Silicon	Si MEMS NOTE: Every company uses a different structure.

How Angular Velocity Sensing Works in Vibration Gyro Sensors

Vibration gyro sensors sense angular velocity from the Coriolis force applied to a vibrating object.
Here, we explain how this works, using as an example Epson 's double-T structure crystal element.

1. Normally, a drive arm vibrates in a certain direction.

2. Direction of rotation

3. When the gyro is rotated, the Coriolis force acts on the drive arms, producing vertical vibration.

4. The stationary part bends due to vertical drive arm vibration, producing a sensing motion in the sensing arms.

5. The motion of a pair of sensing arms produces a potential difference from which angular velocity is sensed. The angular velocity is converted to, and output as, an electrical signal.