Components of a Multicopter: Inertial Measurement Unit (IMU)

Components of a Multicopter: Inertial Measurement Unit (IMU)

Multicopters operate through various components including motors or propellers, electronic speed controller and transmitter and receiver, to name a few. This post will look at one of the most important components of multicopters— Inertial Measurement Unit (IMU). If you are looking to buy a drone (professional drones) or unmanned aerial vehicles, make sure that you consider the IMU of the vehicle before purchase.

What is IMU?

IMU or the internal measurement unit, is an electronic sensor device that gauges the orientation, gravitational forces and velocity of a multicopter using two common devices known as the gyroscopes and accelerometers. The measurements recorded by an IMU allow the control system to calculate the varying speeds of an aerial vehicle. Generally, an IMU is a combination of two devices, as mentioned above, a three-axis gyroscope and three-axis accelerometer. Together both the devices embody a 6DOF IMU. Some multicopters utilize an additional three-axis magnetometer that contributes towards a stabilized yaw.

How does it work?

Now you know what an IMU actually is, let’s move onto its function. If you paid attention in your physics class, then you must remember the function of an accelerometer. If you don’t, an accelerometer is a device that measures the acceleration and force of a vehicle; in this case, an aerial vehicle, whereas a gyroscope measures rotational speed or angular velocity of an aerial vehicle.

Now the question arises, why is it important to use both these devices for IMU? The answer is simple: accelerometer gives us the orientation of the aerial vehicle with reference to the earth’s surface. The multicopter motor sometimes vibrates during the flight which can mess up the accelerometer readings. Therefore, for better and accurate results we use both the devices.

Now, another question arises, if a gyroscope can give us accurate measurements, why utilize accelerometer? Gyroscopes are not always perfect in their operation; they glide a lot and therefore provide inaccurate readings sometimes, which is why both devices are used together to measure the accurate orientation.

Why Use a Magnetometer?

As the name suggests, a magnetometer gauges the strength of magnetic fields. This is the device that helps the vehicle determine which way is east and north. Both accelerometer and gyroscope do not accurately measure the yaw movement of an aerial vehicle as they measure the roll and pitch. Therefore a magnetometer is used to measure the accurate yaw movement.

How to Buy an IMU

Most common IMU sensors include 6DOF Sparkfun combo board, 9DOF Sparkfun stick and free IMU. These three sensors can be easily purchased online through Amazon and eBay; however, make sure that you know what type of sensor you want. After you have decided the type of IMU you want, you can easily find the right controller board. Some controller boards are available with built-in sensors. Therefore, do your research before making a purchase.

Many manufacturers and suppliers that offer UAV for sale and Drones for sale provide substantial information about the various components of a specific multicopter. However, not all suppliers provide in-depth information.

Multicopters operate through various components including motors or propellers, electronic speed controller and transmitter and receiver, to name a few. This post will look at one of the most important components of multicopters— Inertial Measurement Unit (IMU). If you are looking to buy a drone (professional drones) or unmanned aerial vehicles, make sure that you consider the IMU of the vehicle before purchase.

What is IMU?

IMU or the internal measurement unit, is an electronic sensor device that gauges the orientation, gravitational forces and velocity of a multicopter using two common devices known as the gyroscopes and accelerometers. The measurements recorded by an IMU allow the control system to calculate the varying speeds of an aerial vehicle. Generally, an IMU is a combination of two devices, as mentioned above, a three-axis gyroscope and three-axis accelerometer. Together both the devices embody a 6DOF IMU. Some multicopters utilize an additional three-axis magnetometer that contributes towards a stabilized yaw.

How does it work?

Now you know what an IMU actually is, let’s move onto its function. If you paid attention in your physics class, then you must remember the function of an accelerometer. If you don’t, an accelerometer is a device that measures the acceleration and force of a vehicle; in this case, an aerial vehicle, whereas a gyroscope measures rotational speed or angular velocity of an aerial vehicle.

Now the question arises, why is it important to use both these devices for IMU? The answer is simple: accelerometer gives us the orientation of the aerial vehicle with reference to the earth’s surface. The multicopter motor sometimes vibrates during the flight which can mess up the accelerometer readings. Therefore, for better and accurate results we use both the devices.

Now, another question arises, if a gyroscope can give us accurate measurements, why utilize accelerometer? Gyroscopes are not always perfect in their operation; they glide a lot and therefore provide inaccurate readings sometimes, which is why both devices are used together to measure the accurate orientation.

Why Use a Magnetometer?

As the name suggests, a magnetometer gauges the strength of magnetic fields. This is the device that helps the vehicle determine which way is east and north. Both accelerometer and gyroscope do not accurately measure the yaw movement of an aerial vehicle as they measure the roll and pitch. Therefore a magnetometer is used to measure the accurate yaw movement.

How to Buy an IMU

Most common IMU sensors include 6DOF Sparkfun combo board, 9DOF Sparkfun stick and free IMU. These three sensors can be easily purchased online through Amazon and eBay; however, make sure that you know what type of sensor you want. After you have decided the type of IMU you want, you can easily find the right controller board. Some controller boards are available with built-in sensors. Therefore, do your research before making a purchase.

Many manufacturers and suppliers that offer UAV for sale and Drones for sale provide substantial information about the various components of a specific multicopter. However, not all suppliers provide in-depth information.