This article will examine the gyroscope and exactly what is the difference in the number of axis. The truth is there are not really 6 axis in a 6 axis gyroscope, it is just 3 axis with 2 types of sensors.

The Basics: What is a gyro?

A gyro is an electronic device that senses angular velocity. Vibration sensors are used to detect angular velocity from the Coriolis force applied to a vibrating element. They are also known as angular velocity sensors or rate sensors.

The devices that make use of this technology include; aircraft, race cars, motor boats, robots, video games, radio controlled toys, digital cameras and the most common use for the gyro is in your smartphone. These sensors provide stability and direction by sensing motion caused by vibrations. There are many applications of gyro sensors. In navigation systems, it can be used to sense angular velocity produced by the sensor’s movements. These angles are detected through an integration operation by a CPU. You are able to read them using an application. The use of gyros are widespread and even can be applied in athletics to determine a runner’s motion capability.Quadcopters primarily used a 3 axis gyro but the introduction of 6 axis gyros made them more stable.

finger
Close-up of inside a gyro.

How gyros work.

When your device rotates in a certain direction, the gyro sensors sense the motion on the drive arm. When the gyro rotates, the Coriolis force will act on the drive arm to produce a vertical vibration. This triggers the stationary part to bend making the sensing arm detect motion. The angular velocity is therefore determined by the motion of sensing arms. It is then converted and emitted as an electric signal.

There are many applications of gyro sensors. In navigation systems, it can be used to sense angular velocity produced by the sensor’s movements. These angles are detected through an integration operation by a CPU. You are able to read them using an application. The use of gyros are widespread and even can be applied in athletics to determine a runner’s motion capability.

Vibrations caused by external factors can also be sensed by the gyro. It senses the vibrations then transmits the data to a CPU. The vibrations are converted into electric signals that can be read by the computer. The remote operator can correct the orientation or balance of his/her object. This is also used in cameras for correcting shaky footage (electronic image stabilization) and also is how your quadcopter can counteract wind and other interference.

6 axis gyro
InvenSense have a 6 axis gyro that is adopted in many quadcopters, most of the teardowns I have done use these 6 axis gyros. The coloured X,Y and Z are the 3 axis and the black arrows represent the accelerometer.

3 axis Vs 6 axis gyros.

The main difference between a 3 axis and 6 axis gyro is that the latter has 3 accelerometers in addition to the three  standard orientation sensors. The pitch, yaw and roll sensors will navigate your 3 axis copter well but the added feature makes the 6 axis more resistant to altitude displacement.

The accelerometers compensate for any unwanted acceleration or simply movement in the three dimensions. This ensures the quadcopter can fly freely without interference by wind, going too high or falling to the ground. Any user learning to operate remote aircraft can easily make sharp turns by applying the rudder and roll features in the 6 axis too.

The other advantage of a 6 axis quadcopter is that combining the six sensors can detect both unusual attitude and a fall. By centralizing the pitch controls and applying throttle, the 6 axis quad comes to a stable hover. This will help bring it to desired height if it’s flying too high or reposition it to an upright position if it’s flying facing an opposite side like upside down. Even if your quad tumbles while reducing altitude, you just have to increase the throttle before it touches down to make it stable. (Im sure we have all done that before).

I hope this overview has helped your knowledge of the term 6 axis gyro and you now are more informed on a key term and functions of your multirotor. We have a range of affordable quads, hexas and a few octas in our multirotor section, so if you are looking for a new flying gyro have a browse through our range.

Know more than me about gyros?

Share your knowledge below and I will enhance the article with your ideas and critiques.

Leave a Reply

Notify me of
avatar
Phoghat
Phoghat

Thanks. Nice clearly written article

TiagoTiago
TiagoTiago
And a 9 axis “gyro”, is the same thing, but with the addition of a 3 axis magnetometer (compass). The reason the magnetometer doesn’t just replace the accelerometer or the actual gyro is actually 2 reasons; one is that they are slower, when the device turns, the rotation detected by the magnetometer trails behind, and if it rotates one way and then back the other way fast it might not measure it accurately, sorta like a low-pass filter; and the other reason is like the accelerometer, they are only capable of being used to detect a direction but not all… Read more »
anon 49
anon 49

Thanks, helped alot 🙂

wpDiscuz