Inertial Sensor

Accelerometer: The accelerometer measures how fast the sensor changes its motion (accelerates) along the X axis, the Y axis, and/or the Z axis. These axis are determined by the orientation of the Inertial Sensor. For example, one orientation could have a robot’s X axis as its forward and backwards motion, its Y axis as its side to side motion, and its Z axis as its up and down motion (such as the robot lifting itself up off the field on a hanging bar).

Gyroscope: The gyroscope, rather than measuring linear motion along the 3 axis, it measures the rotational motion around the three axis. The sensor measures this rotation when the internal electronics creates a fixed reference point. As the sensor rotates away from this reference point it changes the output signal.

It takes a short period of time for a gyroscope to establish its reference point. This is commonly called the initialization or startup time.