IMU Integration with VB3i - IMU03/YAW03
Required Equipment
- VB3i (works with all VB3i units)
- IMU03
- RLCAB005-CS – VBOX - IMU connecting cable
- RLCAB001 / RLCAB066-2 – VB3i PC connection cable
- VBOX Setup
- VBOX Manager (optional)
- RLCAB069L / RLCAB015L / RLACS182L - vehicle CAN bus cable (optional for wheel speeds)
Setup
Hardware
- Fit the VBOX 3i into the test vehicle, and mount the IMU as described here.
- Fit VBOX 3i GPS, GPS/GLONASS antenna to centre of vehicles roof. Connect antenna to VBOX 3i.
- Measure the relative position from the top centre of the GPS antenna* to the top centre of the IMU (see mounting section for more detail) and enter these distances in the highlighted box below. Measurements need to be made in all 3-axis, X, Y and Z.
*When using a twin antenna system, these measurements must be taken from the main antenna (A). - IMU04 – Connect CAN/KF port to VBOX 3i V3-V5 25W D analogue input port using RLCAB119 cable.
IMU03 – Connect either port on IMU to VBOX RL CAN port using RLCAB005-CS cable. - After IMU is connected, apply power to VB3i.
- Enable IMU integration using either VBOX Manager or VBOX Setup.
VBOX 3i and IMU03
Configuration
VBOX Setup Software
- Ensure IMU04 is connected via RLCAB119, and the VBOX 3i is powered on.
- Connect VBOX 3i to PC using RLCAB001 or RLCAB066-2 cable (RS232 or USB).
- Open VBOX Setup and connect to VBOX 3i by selecting COM Port.
- Select the 'GPS' menu and the 'Settings' tab, ensure that 'GPS Optimisation' is set to 'High dynamics'.
- Select the 'Logging' menu and ensure that 'Log rate' is set to '100 Hz'.
- Select the 'IMU' menu and tick 'Enable IMU integration'.
- Enter the distances measured between the IMU and antenna A, more information on this can be found here.
- If you would like to translate the data from the IMU location to another point on the vehicle where all measurements will be made, enter the x,y,z offset values from the required translation point to the IMU, more information on this can be found here.
- If using IMU04, Internal IMU Attitude channels (Head_imu, Pitch_imu, Roll_imu, Pos.Qual., Lng_Jerk, Lat_Jerk and Head_imu2) will automatically be set to log. If IMU Attitude data is required to be displayed as a Live Serial data display then the user must tick the channels for 'Send over serial'.
- If using IMU04, Serial IMU channels (x accel, y accel, z accel, temp, pitch rate, roll rate and yaw rate) will also automatically be set to log. If Serial IMU data is required to be displayed as a Live Serial data display then the user must tick the channels for 'Send over serial'.
- Select 'Write to unit' to upload settings to VB3i.
- Perform initialisation and full calibration procedure before commencing testing.
VBOX Manager
- Ensure IMU04/03 is connected, and the VBOX 3i is powered on.
- Connect VBOX Manager to the VBOX.
- Enter the 'SETUP' menu of VBOX Manager.
- Select 'IMU-INS' and then click on the 'IMU Integration' menu.
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- Scroll to 'Enable' and select. Once the 'OK' confirmation screen has cleared, 'Enabled' will be displayed.
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- Scroll to the 'Roof Mount' menu and ensure it is 'Disabled'.
- Select 'Ant to IMU Offset' and enter the distances measured between the IMU and antenna A, more information on this can be found here.
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- If you would like to translate the data from the IMU location to another point on the vehicle where all measurements will be made, Select 'IMU to Ref. Offset' and enter the distances measured between the required translation point and the IMU, more information on this can be found here.
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- Internal IMU Attitude channels (Head_imu, Pitch_imu, Roll_imu, Pos.Qual., Lng_Jerk, Lat_Jerk and Head_imu2) will automatically be set to log. If IMU Attitude data is required to be displayed as a Live Serial data display (with VBOX Test Suite), then the user must enter VBOX Setup Software and tick the channels for 'Send over serial'.
- Perform initialisation and full calibration procedure before commencing testing.
- If the IMU is not mounted on a flat surface, perform 'Pitch/Roll Offset' calibration.
This will zero the Pitch_imu and Roll_imu channels. Angle offset calibration must be performed after the IMU Kalman filter calibration has been completed, and the vehicle is static on a level surface.
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- If ADAS testing is being conducted, ensure the 'ADAS Mode' menu shows 'Enabled'.
This setting changes the rate at which the Kalman filter takes a GPS positional sample to improve the positional performance of the filter. Whilst this is beneficial to ADAS testing, it slightly decreases the accuracy of the filtered speed and therefore shouldn't be selected when undertaking speed-based testing such as brake stops.
Note: Option not available with IMU03.
Initialisation
When using IMU integration, an initialisation phase is required when the IMU is first connected to the VBOX after being set up. This will be run through automatically after the VBOX has successfully gained satellite lock. When the IMU LED on VB3i front panel has turned a flashing green, the initialisation is complete. Note, if you are using a VB3i-V1, which has no IMU LED, read the LED indicators section below for LED behaviour.
| IMU03 LED | Colour | Description |
|---|---|---|
| Power | Red | IMU03 / YAW 03 is connected to a live power source. |
| Coms | Blue | Serial or CAN data communications are active. |