LiDAR Resonator Dynamic Force Equilibrium for Low-Vibration Scanning
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Solution Overview
Problem
Current LiDAR systems face reliability issues due to stepper motors used for laser scanning, which are unreliable over long periods and under harsh conditions, leading to noise and vibration, and high-resolution scans are time-consuming, making them impractical for real-time autonomous vehicle operations.
Innovation Solution
A LiDAR resonator with a spring fork mechanism having balanced masses and a voice coil to induce alternating magnetic forces, achieving dynamic force equilibrium, reducing noise and vibration by ensuring out-of-phase resonance, thus stabilizing the scanning mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stepper motors are used to rotate and aim the laser transmitter, then the LiDAR system can achieve laser scanning capability, but the system becomes unreliable over long periods and under harsh environmental conditions
Solution Approach 1:
The patent replaces the traditional stepper motor mechanical scanning system with a resonant mechanical scanning system. The resonant scanner uses a vibrating fork mechanism that oscillates at its natural resonant frequency, eliminating the need for stepper motors and their associated control electronics. This substitution of mechanical principles (resonance vs. stepped rotation) directly improves reliability while reducing device complexity.
Solution Approach 2:
The patent employs mechanical vibration at the resonant frequency of the scanning mechanism to achieve continuous laser scanning. The vibrating fork is driven into resonance, creating predictable oscillatory motion that scans the laser beam across the field of view. This vibration-based approach replaces the incremental stepping mechanism, providing more reliable operation under harsh conditions.
2Measurement precision
If high resolution scans are performed at long distances, then spatial resolution is improved, but the scanning time becomes overly time consuming
Solution Approach 1:
The resonant scanning mechanism operates continuously at its resonant frequency, maintaining constant oscillatory motion to scan the laser beam. This continuous action eliminates the start-stop nature of stepper motor systems, allowing high-resolution scanning to be performed more quickly and efficiently, thereby reducing the time loss associated with scanning.
Solution Approach 2:
The patent utilizes periodic oscillation at the resonant frequency of the scanning mechanism to achieve repeated scanning cycles. This periodic action at optimized frequencies allows the system to rapidly acquire high-resolution depth maps by efficiently covering the entire field of view through resonant vibrations, reducing overall scanning time.
3Speed
If the spring fork mechanism resonates at high frequency, then scanning speed is improved, but noise and vibration increase
Solution Approach 1:
The patent incorporates counterweights on the vibrating fork structure to balance the oscillating masses. These counterweights generate opposing forces that cancel out the harmful vibrations and noise produced during resonant scanning. By applying counterbalancing forces, the system can maintain high scanning speeds through resonant operation while minimizing the harmful noise and vibration that would otherwise be generated.
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 LiDAR resonator achieves reduced noise and vibration, improved operational efficiency, and lower power consumption by maintaining balanced forces, enabling stable and efficient high-resolution scanning for autonomous vehicle applications.
Implementation Method 1
a voice coil, mounted to the first tine, configured to generate an alternating magnetic force at the resonant frequency
Implementation Method 2
the spring fork mechanism is configured to resonate at a resonant frequency
Data Source
AI summary
A LiDAR resonator with dynamic force equilibrium that includes a spring fork mechanism having a first tine and a second tine with the same stiffness as the first tine, wherein the spring fork mechanism is configured to resonate at a resonant frequency, an optical module, mounted to the first tine, for transmitting a light pulse and receiving a reflection of the light pulse, a voice coil, also mounted to the first tine, for generating an alternating magnetic field at the resonant frequency, a counterweight, mounted to the second tine, having a mass and CG equal to a mass and CG of the combined optical module and the voice coil, and a signal source for coupling an alternating current signal at the resonant frequency to the voice coil such that the voice coil is operative to generate an alternating magnetic force at the resonant frequency between the voice coil and the counterweight.