Pavement Profiler Sensor Array for Unevenness Measurement
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Solution Overview
Problem
Current reference profilers for validating road roughness measurements are inadequate due to coarse horizontal distance increments, sensitivity differences with highway-speed laser-based profiling systems, bias errors on textured surfaces, and insensitivity to megatexture, leading to anomalous readings and contractual issues.
Innovation Solution
A method and apparatus using a sensor support frame with an array of sensors to measure pavement surface unevenness by taking precise distance measurements at multiple positions, calculating surface profiles, and generating a sequence of profiles with known relative positions and alignments to accurately assess surface unevenness, including microtexture, macrotexture, and megatexture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If current reference profilers use coarse horizontal distance increments (>240 mm), then device complexity is reduced, but measurement precision deteriorates causing localised roughness features to be missed
Solution Approach 1:
The profiler divides the measurement task into multiple segments by using an array of sensors spaced at fine intervals (e.g., 25 mm). Each sensor independently measures height at its specific location, and the combined data provides comprehensive coverage of both coarse and fine roughness features, resolving the contradiction between device simplicity and measurement precision.
Solution Approach 2:
The invention transitions from single-point measurement to multi-point distributed measurement by arranging sensors in a spatial array. This dimensional expansion from one measurement point to multiple simultaneous measurement points enables capture of localised roughness features while maintaining manageable device complexity through modular sensor array design.
2Ease of operation
If current reference profilers use traditional sensor arrays, then ease of operation is maintained, but measurement precision deteriorates due to sensitivity differences with highway-speed laser-based systems
Solution Approach 1:
The invention changes the critical parameter of sensor spacing from coarse (>240 mm) to fine (e.g., 25 mm) intervals. This parameter modification aligns the reference profiler's measurement resolution with highway-speed laser-based systems, eliminating sensitivity differences while preserving ease of operation through automated data processing.
3Device complexity
If current reference profilers use traditional measurement ranges, then device complexity is reduced, but measurement precision deteriorates due to insensitivity to megatexture (50-500 mm wavelength)
Solution Approach 1:
The invention implements a dynamic measurement approach where the sensor array configuration and data processing algorithms adapt to capture different texture ranges. The fine sensor spacing enables detection of megatexture features (50-500 mm wavelength) while the system maintains the ability to measure microtexture and macrotexture, providing comprehensive texture measurement capability.
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 solution provides accurate and reliable measurements of pavement surface unevenness, reducing errors and improving agreement between different measurement systems, effectively addressing the limitations of current profilers and ensuring precise validation of road roughness data.
Implementation Method 1
an array of laser-based distance measuring sensors attached to the frame and directed downwards
Data Source
AI summary
Measuring the unevenness of a pavement surface. A frame carrying an array of sensors is transported above the pavement surface. At a first position, the distance of each sensor is measured from respective first points on the pavement surface. The measurements are repeated for subsequent positions. Calculations from the measurements determine any change in tilt. The measurements and calculations are used to derive a measure of the unevenness of the pavement surface.