Infrared proximity sensors in high-end automotive applications - Testing and validation of an optical position detection mechanism for an innovative gear selector design

This Master Thesis presents the study and evaluation of a position detection mechanism based on infrared (IR) proximity sensors, applied to a gear selector lever in a high-end vehicle. Starting from an overview of the growing role of electronics in the modern automotive field and the strict functional safety requirements imposed by standards such as ISO 26262, the work focuses on the analysis of an innovative selector design, implemented to satisfy extremely high quality, elegance and ergonomics expectations. The gear selector under consideration is featured by a reverse L-shape, with two directions of movement required to select four different driving modes (P-R-N-D). Moreover, four unstable lever states are added in order to implement warning pop-up messages in case of incorrect shifter use. The thesis investigates how the specific mechanical design of the gear lever affects the choice and performance of position transduction technologies; among several solutions, a system based on four IR proximity sensors (VCNL4030X01) was realized by the external supplier. The transduction mechanism is based on four reflective ramps, one for each proximity sensor, perfectly aligned with the lever positions to be detected, so that each position correspond to a particular range of sensor’s output values. An in-depth physical analysis of the sensors’ operation, supported by dedicated bench testing with custom setups, was carried out to characterize the response of the system under different conditions, trying to reproduce in-vehicle real-world scenarios. Through extensive data collection and statistical evaluation, key vulnerabilities related to stable and unstable positions distinguishability were identified. These findings enabled the proposal of mechanical, logic and procedural improvements, discussed with both the internal development team and the supplier, to improve the reliability of the system. As an outcome, the presented testing procedure has been adopted by the supplier for future validation campaigns to complete the component’s qualification process, through prolonged temperature, vibration and durability performance assessments. The methodology developed demonstrates the importance of an interdisciplinary approach combining physics-based understanding, experimental validation and collaborative problem solving for the design of a reliable automotive component, compliant with safety regulations.are development and characterization of a proximity sensor for automotive applications