LiDAR Mirror Frequency Control for Stable Resonant Scanning
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Solution Overview
Problem
The scanning angle of a mirror in LiDAR systems changes due to deviations in its resonance frequency, caused by environmental factors such as temperature, leading to instability in the scanning process.
Innovation Solution
A mirror control method and device that outputs a control signal to adjust the frequency of the mirror based on feedback signals, using a linear closed-loop control algorithm to maintain stable amplitude gain and ensure consistent scanning angles by determining and correcting errors in the actual amplitude gain relative to a preset threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the mirror operates at resonance frequency for stable scanning, then scanning stability is improved, but environmental temperature changes cause resonance frequency deviation leading to scanning angle changes
Solution Approach 1:
The patent implements a feedback control mechanism where the actual amplitude gain of the mirror is detected and compared with a preset threshold. Based on the error between actual and threshold values, the driving frequency is automatically adjusted to maintain the mirror at its resonance frequency, thereby compensating for environmental temperature changes and keeping scanning stable
Solution Approach 2:
The patent dynamically adjusts the driving frequency parameter of the mirror based on detected amplitude gain variations. By changing the frequency parameter in response to environmental conditions, the system maintains optimal resonance conditions and stable scanning performance despite temperature fluctuations
2Reliability
If closed-loop control is implemented to maintain amplitude gain stability, then scanning angle consistency is improved, but system complexity increases
Solution Approach 1:
The system uses feedback control by detecting the feedback signal from the scanning mirror, determining actual amplitude gain, comparing it with a preset threshold, and adjusting the driving frequency based on the error. This closed-loop approach ensures scanning angle consistency while managing complexity through a focused control strategy
Solution Approach 2:
The patent replaces complex mechanical adjustment mechanisms with an electronic control system that adjusts frequency electronically. This substitution reduces mechanical complexity while achieving the same goal of maintaining stable scanning angles through electronic frequency modulation
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 method and device implement closed-loop control of the mirror's amplitude gain, stabilizing the scanning process and maintaining the specified scanning angle, even when the resonance frequency deviates, thereby addressing the instability caused by environmental factors.
Implementation Method 1
combining horizontal scanning and vertical scanning into two-dimensional scanning, and forming a two-dimensional planar array by scanning through specular reflection when a laser beam reaches the vibrating mirror
Implementation Method 2
The mirror is driven by an input single-frequency signal to scan through a simple harmonic motion. The mirror can reach a suitable angle during scanning within a safe gain only when working on resonance frequency
Data Source
AI summary
Embodiments of this application disclose a mirror control method and device and a LiDAR, pertaining to the field of LiDAR. The method includes: outputting a control signal configured to control a mirror to scan; detecting a feedback signal of the scanning mirror; determining an actual amplitude gain of the mirror based on the feedback signal, and determining an error of the actual amplitude gain relative to a preset amplitude gain threshold; and determining a frequency adjustment based on the error, adjusting frequency based on the frequency adjustment, and obtaining an output signal. In the embodiments of this application, stability of a scanning angle of the mirror can be maintained when resonance frequency of the mirror deviates.