Design and Performance of Wheel-mounted MEMS IMU for Vehicular Navigation

In modern cars MEMS gyroscopes and accelerometers provide essential measurements for enhancing the stability and control. Both types of sensors have significant noise at low frequencies, limiting the measurement accuracy especially in low dynamic conditions. In addition, uncompensated accelerometer tilt causes large bias to acceleration estimates. For gyroscopes, physical rotation of the sensor can be used to remove the constant part of the gyro errors and reduce low-frequency noise. In ground vehicles such rotation exists conveniently in wheels. When inertial sensors are attached to wheel, both types of sensors provide information on the rotation, gyroscopes naturally and accelerometers via specific force measurement. In addition, as a result of carouseling, accurate wheel heading, roll and pitch estimation can be estimated with high resolution, and the result is nearly bias-free. Combining the wheel orientation to distance traveled via known radius enables classic dead reckoning mechanization (assuming zero slip) and other vehicle dynamics monitoring systems (considering wheel slip as unknown to be solved). In the paper, we provide details of wheel-mounted inertial system hardware and algorithms and show test results for several system configurations and applications. We discuss future system improvements, in particular, system miniaturization and an energy-harvesting development progress for next-generation inertial systems.