Road Surface Laser Sensing for Low-Speed Grip Detection
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Solution Overview
Problem
Existing systems for estimating tire grip on the road surface are ineffective at low speeds or when a vehicle is parked, leading to potential safety hazards due to delayed or inaccurate detection of road conditions.
Innovation Solution
A motor vehicle equipped with an optical sensor system using single-photon avalanche diodes and a control unit to detect road surface conditions by analyzing laser signals reflected from the road, including mirror-like and diffuse reflections, to determine the grip coefficient accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If capacitive, piezoelectric or optical sensors are used to detect road surface conditions, then temperature and humidity measures can be obtained, but the detection is only effective at high travel speeds close to the grip limit
Solution Approach 1:
The patent replaces traditional capacitive, piezoelectric or optical sensors that rely on temperature and humidity measures with a laser-based detection system. The system uses a laser emitter to project laser beams onto the road surface and detectors to analyze the reflected light properties, thereby substituting mechanical/thermal sensing with optical sensing that works effectively at all vehicle speeds including low speeds and stationary conditions.
Solution Approach 2:
The invention changes the detection parameter from temperature and humidity to optical properties of reflected laser light. By measuring the intensity, polarization state, and other optical characteristics of light reflected from the road surface, the system can determine road surface conditions (dry, wet, icy, snowy) without being dependent on vehicle speed or thermal properties of the environment.
2Device complexity
If grip coefficient estimation is performed only at high travel speeds, then the system can operate with simpler sensors, but the detection of potential danger is delayed or inconsistent with actual grip conditions
Solution Approach 1:
The laser-based detection system enables preliminary detection of road surface conditions before the vehicle reaches high speeds or before hazardous situations develop. The system can detect changes in road surface conditions in advance, allowing the vehicle control system to prepare appropriate responses before the vehicle actually encounters grip-limiting conditions.
Solution Approach 2:
By replacing speed-dependent mechanical sensing with optical sensing, the system achieves timely detection without requiring complex high-speed data processing mechanisms. The optical detection method provides immediate feedback on road surface conditions regardless of vehicle speed, eliminating the delay inherent in systems that only activate at high speeds.
3Speed
If traditional sensors are used for road surface detection, then the system can operate at high speeds, but the detection accuracy decreases at low speeds and when parked
Solution Approach 1:
The patent substitutes traditional sensors that measure temperature and humidity with a laser optical detection system. This substitution enables precise measurement of road surface conditions at all speeds because optical properties of reflected light are independent of vehicle motion. The laser system measures the polarization state and intensity of reflected light, which directly correlate with road surface friction characteristics regardless of vehicle speed.
Solution Approach 2:
The invention changes the measurement parameter from thermal properties (temperature, humidity) to optical properties (light intensity, polarization). This parameter change enables consistent and precise detection of road surface conditions across the entire speed range, including low speeds and stationary conditions where thermal sensors are ineffective.
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 and timely detection of road surface conditions, enhancing driving safety at low speeds and when the vehicle is stationary, by processing laser signal intensities and polarizations to identify conditions such as wet, icy, or snow-covered surfaces.
Implementation Method 1
an emitter (15) configured to emit a laser signal (R) towards a road surface (16)
Implementation Method 2
one or more single-photon avalanche diodes (11a, 11b, 11c) configured to detect laser signals (S, T, U) reflected by the road surface (16)
Implementation Method 3
the laser beams (S, T) are polarised in a plane (P) and in a plane (Q)
Implementation Method 4
one or more single-photon avalanche diodes (11a, 11b, 11c) configured to detect laser signals (S, T, U)
Data Source
AI summary
A motor vehicle comprising a body defining a passenger compartment, a plurality of wheels; and a sensor designed to detect a parameter associated with a superficial condition of a road surface; the sensor comprises, in turn, an emitter configured to emit a first laser signal towards a road surface; and one or more single-photon avalanche diodes configured to detect a second laser signal corresponding to the reflection of the first laser signal against said road surface.