Today, I'd like to share a very interesting topic - how do gyroscopes work?

Especially when seeing the XV7118BB gyroscope, I couldn't help but want to delve deeper into its working principle, shock resistance, and its applications in industry and autonomous driving. To understand how it works, we first need to understand what is a Gyroscope?

A gyroscope sensor is a device specifically designed to measure angular velocity.

Angular velocity refers to the change in an object's rotation angle per unit time, usually expressed in °/s or °/h. This sensor can detect the tilt or turning angle of an object within one second, making it very useful for position correction.

For example, in DSLR cameras, the gyroscope sensor captures the angular velocity of lens shake and adjusts the lens direction accordingly to ensure stable images.

Of course, the applications of gyroscope sensors are very extensive. Besides DSLR cameras, they are also used in vehicle navigation systems, especially when GNSS signals are unavailable, such as in tunnels or between tall buildings.

In these situations, the vehicle's position can be estimated using the number of tire rotations and the gyroscope sensor. Additionally, gyroscope sensors are used in electronic stability control, side airbags, automated guided vehicles (AGVs), drones, robotic vacuum cleaners, and construction machinery. It plays a key role in determining direction of travel and distance traveled.

How does a gyroscope sensor work?

Working Principle: Based on the inverse piezoelectric effect and Coriolis force.

When a power supply voltage is applied to the sensor's double-trapezoidal structure made of quartz material, the drive arms vibrate. Once rotational motion is applied to the sensor, it can detect angular velocity. The rotational motion causes a driving force to be generated perpendicular to the driving vibration direction, which in turn causes the sensing arms to bend and vibrate in opposite directions. This vibration is converted into an electrical signal via the piezoelectric effect, with its amplitude proportional to the angular velocity. The electrical signals generated by the upper and lower sensing arms are differentially added, doubling the amplitude based on the angular velocity.

Gyroscope sensors have very strong shock resistance. Even when subjected to shock, the sensor does not output any signal. This is because a shock causes the upper and lower sensing arms to bend and vibrate in the same direction. The electrical signals generated due to the piezoelectric effect have amplitudes proportional to the acceleration in the bending direction and are in phase. When these in-phase signals are differentially summed, the electrical signals generated by the impact cancel each other out.

Therefore, even if the sensor is subjected to shock, no noise is generated, and the detection of angular velocity is unaffected.

The Importance of Gyroscope Shock Resistance

In application scenarios such as industry and autonomous driving, gyroscopes need to operate in various complex environments. External shocks, vibrations, and temperature changes can all affect the measurement accuracy of the gyroscope. Therefore, shock resistance is one of the important performance indicators of a gyroscope.

How is Gyroscope Shock Resistance Achieved?

1.  Mechanical Design: Optimizing the mechanical structure of the gyroscope to improve its shock resistance.

2.  Electronic Design: Designing high-precision electronic circuits to reduce the impact of external interference on measurement results.

3.  Software Algorithms: Designing advanced algorithms to perform real-time correction of measurement data, improving measurement accuracy.

Advantages of XV7118BB Gyroscope

-   SPI / I2C Serial Interface

-   Angular Rate Output (16-bit / 24-bit)

-   Excellent Temperature Bias Stability

-   Operating Temperature Range: -40°C to +85°C

-   Built-in Temperature Sensor

-   Built-in Selectable Digital Filter

Suggested Applications

-   Vibration Protection and Attitude Control for Industrial Applications, etc.

-   Autonomous Driving Equipment, such as AGVs and Lawn Mowers