VCSEL Multi-Spot Laser Imaging for Vehicle Dynamics Correction
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Solution Overview
Problem
Existing vehicle dynamics sensors face measurement errors due to vehicle orientation changes, particularly roll and pitch movements, which compromise the accuracy of speed measurements using self-mixing interference sensors.
Innovation Solution
A laser diode-based, VCSEL-based multi-spot laser imaging system that directs multiple laser beams onto a reference surface, such as a road, with an imaging system to measure spot locations and separations, allowing for the correction of systematic errors in ground speed measurements by determining pitch and roll angles and incorporating these into a rotation matrix for improved accuracy and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single laser beam self-mixing sensor is used for ground speed measurement, then the device complexity is low, but the measurement precision deteriorates due to vehicle roll and pitch movements
Solution Approach 1:
The patent divides a single laser beam into multiple parallel beams using a beam splitting element. Each beam independently measures the road surface position, and by analyzing the relative positions of multiple measurement points, the system calculates vehicle roll and pitch angles to correct ground speed measurement errors, thereby improving measurement precision without requiring multiple separate sensors
Solution Approach 2:
The single laser beam system is made multi-functional by adding a beam splitting element that enables both direct ground speed measurement and indirect orientation measurement (roll and pitch angles) simultaneously. The same laser source serves dual purposes: measuring vehicle speed and measuring vehicle orientation, thus improving measurement precision while avoiding the complexity of separate sensor systems
2Measurement precision
If multiple laser beams are used to correct for vehicle orientation, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
A beam splitting element is introduced as an intermediary component that takes a single laser beam and divides it into multiple parallel beams. This intermediary device enables the system to obtain multiple measurement points for calculating vehicle orientation, improving measurement precision while avoiding the need for multiple independent laser sources and their associated control systems
Solution Approach 2:
The patent creates multiple copies of the laser beam path by using a beam splitting element to generate parallel beams that follow identical optical paths to the road surface. Each beam creates a corresponding measurement point, and these copied measurement paths provide the data needed for orientation correction, improving precision without proportionally increasing system complexity
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
The system significantly enhances the absolute accuracy and reliability of ground speed measurements by correcting for vehicle dynamics, reducing measurement errors and providing detailed information on vehicle orientation and loading status, while also monitoring for laser failures and environmental conditions.
Implementation Method 1
laser self-mixing interference (SMI) can be used for speed and distance measurements
Implementation Method 2
A compact imaging system including an imaging matrix sensor such as a CCD or CMOS camera measures locations, separations or distances of individual laser spots
Implementation Method 3
laser self-mixing interference (SMI) can be used for speed and distance measurements
Data Source
AI summary
The invention is related to a laser diode based multiple beam laser spot imaging system for characterization of vehicle dynamics. A laser diode based, preferably VCSEL based laser imaging system is utilized to characterize the vehicle dynamics. One or more laser beams are directed to the road surface. A compact imaging system including an imaging matrix sensor such as a CCD or CMOS camera measures locations or separations of individual laser spots. Loading status of vehicles and vehicles' pitch and roll angle can be characterized by analyzing the change of laser spot locations or separations.