Multi-LiDAR Trailer Angle Measurement System
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Solution Overview
Problem
Existing methods for measuring trailer angles in semi-trailers are inaccurate for large angles, as the laser light emitted by a single LiDAR may not reach the reflective surface when the trailer angle is greater than ±40°, leading to unreliable measurements.
Innovation Solution
The implementation of at least one LiDAR on each side of the tractor's rear part, with a reflector having a reflective surface on the trailer, allows for the emission and reception of laser light, enabling accurate trailer angle calculation based on corresponding laser point clouds from multiple LiDARs, ensuring measurement accuracy even for large angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single LiDAR is used for trailer angle measurement, then the device complexity is reduced, but the measurement precision deteriorates for large trailer angles
Solution Approach 1:
The measurement system is segmented into multiple LiDAR units distributed at different positions (front, rear, left, right sides of the tractor). Each LiDAR independently measures the trailer angle from its specific viewpoint, and the final result is obtained by fusing these segmented measurements, thereby maintaining high precision across all angle ranges while keeping each individual sensor simple.
Solution Approach 2:
Multiple LiDAR measurement results are merged through data fusion algorithms to produce a comprehensive trailer angle measurement. By combining the measurements from different positions, the system overcomes the limitations of single-point measurement and achieves high accuracy across the full range of trailer angles, resolving the contradiction between device simplicity and measurement precision.
2Measurement precision
If multiple LiDARs are deployed at different positions, then the measurement precision for large angles is improved, but the device complexity increases
Solution Approach 1:
Each LiDAR unit serves multiple functions: it can measure trailer angle, detect obstacles, and provide spatial positioning information. This multi-functionality justifies the deployment of multiple sensors, as they perform various measurement tasks simultaneously, thereby improving overall system efficiency and reducing the need for additional specialized components.
Solution Approach 2:
The system transitions from single-point measurement to multi-dimensional measurement by placing LiDARs at multiple spatial positions (front, rear, left, right). This dimensional expansion enables the system to capture trailer angle information from multiple perspectives, significantly improving measurement precision for large angles while the distributed architecture actually reduces overall system complexity by eliminating the need for complex mechanical measurement mechanisms.
3Device complexity
If LiDARs are placed only at the rear of the tractor, then the device complexity is minimized, but the adaptability to large trailer angles deteriorates
Solution Approach 1:
The LiDAR distribution follows an asymmetric pattern optimized for trailer angle measurement, with LiDARs positioned at the front, rear, and both sides of the tractor. This asymmetric arrangement ensures that at least one LiDAR maintains a favorable measurement angle regardless of the trailer's deflection direction, greatly enhancing the system's adaptability to large trailer angles while maintaining reasonable structural simplicity.
Solution Approach 2:
LiDARs are pre-positioned at multiple locations on the tractor before operation, creating a distributed measurement network that is already optimized for various trailer configurations. This preliminary arrangement ensures that when the trailer deflects to any angle, the measurement capability is immediately available without requiring additional mechanical adjustments or reconfigurations, thus improving adaptability while keeping the system simple.
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
This solution ensures fast and accurate measurement of trailer angles, improving accuracy by utilizing multiple LiDARs to calculate the angle based on received laser point clouds, which enhances the reliability of measurements across a wider range of angles.
Implementation Method 1
controlling the LiDAR provided on each of the two sides of the rear part of the tractor to emit laser light
Implementation Method 2
the reflective surface of the reflector reflects the laser light emitted by the LiDAR
Data Source
AI summary
The present disclosure provides a method, an apparatus and a vehicle for trailer angle measurement, applied in a semi-trailer including a tractor and a trailer. At least one LiDAR is provided on each of two sides of a rear part of the tractor. A reflector with a reflective surface is fixedly provided at a front part of the trailer, and the reflective surface faces the LiDARs. The method includes: controlling the LiDARs to emit laser light, such that the reflective surface of the reflector reflects the laser light; controlling each of the LiDARs to receive a corresponding laser point cloud reflected by the reflector; and calculating a trailer angle based on the corresponding laser point clouds. The method and apparatus can increase the range of trailer angle measurement, such that the trailer angle can be measured even if the trailer angle is relatively large.