Self-Mixing Laser Sensor for Vehicle Stability Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current electronic stability program (ESP) sensors are unable to explicitly measure vehicle body side slip angle and tire slip angles, which are critical for determining vehicle stability and detecting understeer or oversteer conditions.
Innovation Solution
An optical sensor device using self-mixing laser sensors with multiple laser diodes positioned at different angles along the vehicle measures vehicle dynamics parameters such as side slip angle, tire slip angles, yaw rate, and turn radius, allowing for the detection of understeer or oversteer conditions without the need for additional sensors like steering angle and acceleration sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ESP sensors (steering angle sensor, lateral acceleration sensor, vehicle yaw rate sensor, wheel rotation sensor) are used, then the system can measure basic vehicle dynamics parameters, but the system cannot explicitly measure vehicle body side slip angle and tire slip angles
Solution Approach 1:
The patent replaces mechanical sensors (acceleration sensors, steering angle sensors) with optical laser self-mixing sensors that use light interference patterns to detect vehicle dynamics. The laser sensors measure the Doppler shift of reflected light from the road surface to determine velocity components, from which side slip angle and tire slip angle are calculated, eliminating the need for mechanical measurement devices.
Solution Approach 2:
The laser self-mixing sensor performs multiple measurement functions simultaneously - it measures both longitudinal and lateral velocity components, from which multiple parameters including side slip angle, tire slip angle, yaw rate, and acceleration can be derived. This multi-functional approach replaces multiple specialized sensors with a single optical sensor system.
2Measurement precision
If multiple laser diodes are positioned at different angles to measure multiple velocity components, then precise determination of side slip angle and tire slip angle is achieved, but the device complexity increases
Solution Approach 1:
The measurement function is segmented into multiple laser diodes, each oriented at different angles to detect specific velocity components. By dividing the measurement task across multiple sensors with specialized orientations, the system achieves comprehensive velocity component detection while maintaining modular simplicity in each individual laser device.
Solution Approach 2:
The patent transitions from single-dimensional measurement to multi-dimensional measurement by positioning laser diodes at different spatial angles. This three-dimensional arrangement of laser beams allows simultaneous measurement of longitudinal and lateral velocity components, enabling calculation of slip angles that require multi-axis velocity data.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise determination of vehicle stability parameters, allowing for effective electronic stability control by detecting understeer or oversteer conditions and initiating appropriate interventions, such as brake or torque adjustments, based on yaw rate, turn radius, and tire slip angle analysis.
Implementation Method 1
an optical sensor device for determining vehicle dynamic conditions is provided, comprising a first laser device with at least one laser diode mounted on a vehicle at a first position so that the laser light impinges onto the road surface under an oblique angle
Implementation Method 2
at least one detector for detecting self-mixing oscillations of the laser intensity of the laser diodes
Implementation Method 3
The undulation frequency thereby is proportional to the velocity of the external reflector
Data Source
AI summary
The invention is related to laser diode based self-mixing laser sensors for simplified vehicle stability control. Vehicle's side slip angle, front and rear tire slip angles, yaw rate and lateral acceleration rate are derived explicitly from self-mixing laser sensors. Three criteria based on yaw rate, turn radius and tire slip angle analysis are employed to detect the occurrence of understeer or oversteer, which enables simplified vehicle electronic stability program.