Accelerometer-based monitoring of steering wheel angle

Tato bakalářská práce se zabývá návrhem zařízení pro snímání úhlu natočení volantu. Cílem bylo navrhnout základní koncept zařízení využívající data ze tří akcelerometrů a k tomuto zařízení navrhnout základní rekonstrukční algoritmus. V práci jsou postupně rozebrané různé verze rekonstrukčního algoritmu, které v sobě zahrnují i simulaci šumu reálných akcelerometrů. Rekonstrukční algoritmus byl realizován v prostředí MATLAB Simulink. Dále se práce zabývá výběrem vhodných komponent. Jedná se především o výběr akcelerometrů, mikrokontroléru a volbu vhodné komunikační sběrnice pro vzájemnou komunikaci mezi nimi. Následně se práce věnuje vylepšením rekonstrukčního algoritmu a praktické realizace celého zařízení. V závěru porovnáváme výsledky výsledného zařízení se snímačem vestavěným v testovacím volantu.This thesis deals with the design of a device which will be used for measuring the steering wheel angle. Main goal was to design basic concept of device which is using data gathered from three accelerometers in the reconstruction algorithm to get steering wheel angle. Discussion of various reconstruction algorithms (with regards to simulated output noise levels from acceleromater) and final Implementation of reconstruction algorithm (in MATLAB simulink enviroment) is also part of this thesis. Furthermore, thesis deals with the selection of suitable components. Mainly selection of accelerometers, microcontroller and the selection of a suitable communication bus for mutual communication between them. Thesis also deals with design improvements of algorithm and realization of the whole device. In the end, we compare results of measuring device and inner senzor of steering wheel.

Steering Angle Assisted Vehicular Navigation Using Portable Devices in GNSS-Denied Environments

Recently, land vehicle navigation, and especially by the use of low-cost sensors, has been the object of a huge level of research interest. Consumer Portable Devices (CPDs) such as tablets and smartphones are being widely used by many consumers all over the world. CPDs contain sensors (accelerometers, gyroscopes, magnetometer, etc.) that can be used for many land vehicle applications such as navigation. This paper presents a novel approach for estimating steering wheel angles using CPD accelerometers by attaching CPDs to the steering wheel. The land vehicle change of heading is then computed from the estimated steering wheel angle. The calculated change of heading is used to update the navigation filter to aid the onboard Inertial Measurement Unit (IMU) through the use of an Extended Kalman Filter (EKF) in GNSS-denied environments. Four main factors that may affect the steering wheel angle accuracy are considered and modeled during steering angle estimations: static onboard IMU leveling, inclination angle of the steering wheel, vehicle acceleration, and vehicle inclination. In addition, these factors are assessed for their effects on the final result. Therefore, three methods are proposed for steering angle estimation: non-compensated, partially-compensated, and fully-compensated methods. A road experimental test was carried out using a Pixhawk (PX4) navigation system, iPad Air, and the OBD-II interface. The average Root Mean Square Error (RMSE) of the change of heading estimated by the proposed method was 0.033 rad/s. A navigation solution was estimated while changes of heading and forward velocity updates were used to aid the IMU during different GNSS signal outages. The estimated navigation solution is enhanced when applying the proposed updates to the navigation filter by 91% and 97% for 60 s and 120 s of GNSS signal outage, respectively, compared to the IMU standalone solution