1. MEMS wheel sensor for vehicle navigation, ESC and adaptive suspension systems
| Oleg Mezentsev | “iSense-SK” LLC |
| September, 2015 |

2. Wheel IMU concept Low-cost MEMS unit
Novel “carousing processing method” for long-term accurate 2D navigation in GNSS harsh environments
“horseshoe” design - balanced and easy to install on a bike/motorbike axle via an additional mounting fixture;
size and volume can be dramatically decreased for specific client applications

3. What is a wheel IMU
Inertial MEMS gyros and accelerometers on the wheel
Battery powered (energy harvesting)
Bluetooth (or similar) data transfer to onboard computer
Rotation of the wheel - free source of constant “calibration”
“Calibration” is a novel carousing algorithm that outputs unbiased heading and roll wheel angles and centripetal accelerations of each wheel where it is installed

4. Real-time prototype

5. Real-time prototype Bluetooth: Stollmann BlueMod+SR
Processor: Atmel SAM4S16B
Embedded software: C/C++ (Rowley CrossWorks)
In-vehicle computer (Android tablet): Java (Android Studio)
Wheel IMU - onboard tablet communication: BT4.0
Wheel IMU raw data is recorded on miсroSD card.

6. Markets for wheel IMU
autonomous vehicular navigation: accurate and yet low-cost addition to INS/GPS/LiDAR/Radar systems
container handling machines operated in harsh GNSS environments; mining and warehouse (storage) machines for improved logistics
raw data from wheel: vehicle ESC; monitoring of expensive tires wear, adaptive suspension

7. Early prototype tests: no ZUPTs, GPS as reference
conditions: driving up to 30 km/hour, 30 minutes. Final 2D error: less than 100 meters
Wheel IMU

8. Early prototype tests: no ZUPTs, GPS as reference
Green - DGPS
Blue - wheel IMU
Red - gyro + odometer
13 minutes run; speed up to 40 km/h
final error: <40 meters

9. Motorcycle traction control? Yes!
Bosch Engineering is actively developing a traction control systems for motorbikes
unbiased wheel heading and roll angles, coupled with centripetal accelerations - essential information for reliable traction control
picture above is from Youtube video “2013 Bosch Motorcycle Traction Control 'Acceleration out of a corner' promotional video” -

10. Radius and center of curvature estimation

11. Why is it better than other systems/methods?
Classical INS/GNSS with vehicle dynamic models: either too expensive for many markets or small accuracy when GNSS is not available
Odometer + vertical gyro: limited accuracy of differential odometers; odometers not always available; quickly growing errors from gyro bias
We propose something new - no one ever explored and came up with a method of significantly improving MEMS sensor performance installing them right on vehicle wheels
New markets and new technology will develop!

12. Contacts
We look for partners, customers, investors and anyone who wants to know and explore more of this new, emerging technology!
Oleg Mezentsev
Jussi Collin