The e-puck robot is equipped with 3D accelerometer placed as illustrated here:

Next figure is the data acquisition when taking the e-puck and putting it back on a table making a circular mouvement in YZ plan direction (on the horizontal axis you have the sample number, on the vertical axis the values acquired on the three axis):

Next figure is the data acquisition with a 3D random movement (on the horizontal axis you have the sample number, on the vertical axis the values acquired on the three axis):

When the robot moves, the steppers motors perform a given number of steps per seconds. At each step there is a strong micro-acceleration and micro-deceleration of the robot. Next figure shows the acceleration measured by the accelerometer and due to the stepper motor when moving at 70steps/s. Sampling is made at 7kHz. On the X axis there is the sample number.