Lidar Scanning Platform With Lissajous Frequency Ratio
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Solution Overview
Problem
Existing scanning lidar systems face challenges in achieving high angular resolution and efficient three-dimensional imaging, particularly in applications like autonomous vehicles, where traditional two-dimensional scanning methods are affected by road bumps and result in positional inaccuracies due to uneven scanning frequencies.
Innovation Solution
A scanning lidar system with a fixed frame, a first platform, and a first electro-optic assembly, featuring a drive mechanism that scans in two dimensions with frequencies in a Lissajous pattern, where the ratio of the frequencies is between 0.5 to 2.0, allowing for fast and uniform scanning in both horizontal and vertical directions, and a method of three-dimensional imaging using this system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional two-dimensional scanning methods are used, then the scanning system can operate, but positional inaccuracies occur due to uneven scanning frequencies affected by road bumps
Solution Approach 1:
The patent applies dynamics by transitioning from static, uniform scanning frequencies to dynamic, adaptive scanning frequencies. The system continuously adjusts the scanning frequencies in response to detected road conditions, allowing the lidar to maintain accurate spatial mapping despite vehicle motion on uneven surfaces. This dynamic adaptation resolves the contradiction between operational continuity and measurement precision.
Solution Approach 2:
The system implements feedback by using the lidar's spatial mapping data to detect road bumps and subsequently adjusting scanning frequencies based on this information. The feedback loop compares expected versus actual spatial features, identifies anomalies caused by road irregularities, and modifies the scanning pattern to compensate, thereby maintaining positional accuracy despite external disturbances.
2Measurement precision
If fast scanning is implemented in both directions, then angular resolution improves, but scanning pattern uniformity deteriorates with traditional methods
Solution Approach 1:
The patent employs dynamics by making scanning frequencies adaptive rather than fixed. The system dynamically adjusts the relative frequencies of scanning in different directions based on detected spatial features, enabling fast scanning that maintains both high angular resolution and pattern uniformity. This resolves the contradiction by allowing frequency modulation that preserves scanning regularity despite increased speed.
Solution Approach 2:
The system applies parameter changes by modifying the scanning frequency parameters in response to detected environmental features. When road bumps or spatial anomalies are detected, the system changes the frequency parameters to maintain uniform scanning patterns, thereby achieving fast scanning without sacrificing pattern regularity or angular resolution.
3Productivity
If scanning frequencies in two directions are made similar, then scanning efficiency improves, but positional inaccuracies increase due to resonance and uneven coverage
Solution Approach 1:
The patent uses feedback to continuously monitor the scanning pattern coverage and spatial mapping quality. When similar frequencies cause resonance or uneven coverage, the feedback mechanism detects these conditions and adjusts the frequency ratio away from unity, thereby maintaining both high scanning efficiency and accurate spatial mapping through adaptive frequency selection.
Solution Approach 2:
The system applies parameter changes by dynamically adjusting the frequency ratio parameter based on detected spatial features and scanning performance. Rather than fixing the frequency ratio, the system modifies this parameter in real-time to optimize both scanning efficiency and mapping accuracy, resolving the contradiction between productivity and measurement precision.
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 enables fast and uniform scanning in both directions, resulting in improved angular resolution and accurate three-dimensional imaging, with the Lissajous pattern providing dense coverage of the field of view and minimizing positional inaccuracies.
Implementation Method 1
a first flexure assembly flexibly coupling the first platform to the fixed frame
Implementation Method 2
a first laser source and a first photodetector mounted on the first platform
Implementation Method 3
a method of three-dimensional imaging using a scanning lidar system
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A scanning lidar system includes a fixed frame, a first platform, and a first electro-optic assembly. The first electro-optic assembly includes a first laser source and a first photodetector mounted on the first platform. The scanning lidar system further includes a first flexure assembly flexibly coupling the first platform to the fixed frame, and a drive mechanism configured to scan the first platform with respect to the fixed frame in two dimensions in a plane substantially perpendicular to an optical axis of the lidar system. The scanning lidar system further includes a controller coupled to the drive mechanism. The controller is configured to cause the drive mechanism to scan the first platform in a first direction with a first frequency and in a second direction with a second frequency. The second frequency is similar but not identical to the first frequency.