VBOX 3i User Guide
Page 34 of 46
28/08/2013
Hardware Set Up
1. Setup the VBOX 3i in the vehicle as you would normally.
2. A laptop or Q1 connected to the VBOX 3i is required for the setup of the IMU to view the live X-accel and Y-accel values.
3. Position the vehicle on flat ground with the engine off but the ignition on to allow the VBOX 3i to remain powered. This prevents engine vibration creating
erroneous IMU readings during IMU setup.
4. The IMU should be placed along the centreline of the vehicle and fixed in position to prevent it from moving around while the vehicle is in motion.
Use a mounting procedure that allows small movement in the X and Y planes in order align the IMU perfectly.
If available a tilt table can be used to accurately align the IMU to ensure the Kalman filter uses IMU data that is as accurately aligned with the vehicle.
5. Adjust the position of the IMU while observing the resulting change of the IMU X-accel and Y-accel values on a live display in VBOX Tools.
By changing the position of the IMU in Pitch and Roll it should be possible to achieve values of X-accel and Y-accel very close to zero.
For the best possible IMU integration results the IMU should be aligned so that the X and Y-accel values are 0g +/-0.01g
NB
: The IMU accelerations where chosen as the main setup input as using the X-accel and Y-accel values assumes that the IMU sensors are aligned as close to
zero as possible and any errors introduced by sensor alignment will be small for the range of angles the IMU is likely to encounter.
NB:
Positive Pitch equates to a positive Longitudinal Acceleration, Positive Roll angle equates to a positive Lateral Acceleration.
