Elastomer-Mounted Polygon Mirror for LiDAR Rotor Stability
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Solution Overview
Problem
LiDAR systems face issues due to the mismatch in coefficients of thermal expansion (CTE) between glass-based polygon mirrors and metal-based motor rotor bodies, leading to stress, wobbling, and potential damage from temperature variations, shock, and vibration, which affect the system's performance.
Innovation Solution
Incorporating an elastomer piece with a clamping mechanism to absorb stress and apply compression forces, optimizing the material and dimensions to mitigate CTE mismatch and reduce the likelihood of glass fracturing, while ensuring proper mechanical stability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a glass-based polygon mirror is directly mounted to a metal-based motor rotor body, then the mechanical connection is simple and device complexity is reduced, but the mismatch in coefficients of thermal expansion causes stress, wobbling, and potential damage under temperature variations and vibration
Solution Approach 1:
An elastomer mounting structure is introduced as an intermediary component between the glass-based polygon mirror and the metal-based motor rotor body. This elastomer structure absorbs differential thermal expansion and vibration, preventing stress concentration and mirror damage while maintaining a relatively simple overall mounting configuration.
Solution Approach 2:
The mounting structure uses a composite approach by combining glass (polygon mirror), elastomer (mounting structure), and metal (motor rotor body) materials. This multi-material construction allows each material to发挥 its advantageous properties: glass for optical reflection, elastomer for shock absorption and thermal expansion accommodation, and metal for structural support and motor integration.
2Stability of the object's composition
If the polygon mirror is firmly clamped to the motor rotor body to eliminate wobbling, then stability is improved, but stress concentration increases and may cause glass fracturing
Solution Approach 1:
The elastomer mounting structure changes the mechanical parameters of the connection by providing compliant, stress-distributing contact surfaces. The elastomer's viscoelastic properties allow it to deform under load, distributing clamping forces evenly across the mirror mounting surfaces and avoiding stress concentration that would lead to glass fracturing.
Solution Approach 2:
The elastomer material serves as a cushioning element that is pre-installed between the mirror and motor rotor body. It absorbs and dissipates shock and vibration energy before it can be transmitted to the glass mirror, preventing impact-induced fracturing while maintaining operational stability.
3Reliability
If the mounting structure is designed to accommodate thermal expansion differences, then reliability under temperature variation is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The elastomer mounting structure is specifically designed to accommodate thermal expansion differences between the glass mirror and metal motor rotor body. The elastomer's high elastic modulus and Poisson's ratio allow it to expand and contract with temperature changes while maintaining secure mechanical contact, effectively absorbing differential thermal expansion without requiring complex compensation mechanisms.
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 effectively reduces wobbling and enhances the stability and reliability of the polygon mirror, improving the LiDAR system's performance under varying environmental conditions by compensating for CTE mismatch and absorbing shock and vibration.
Implementation Method 1
an elastomer piece configured to absorb the stress caused by the various environmental conditions (e.g., temperature variation, vibration, and shock)
Implementation Method 2
fastening mechanisms configured to apply proper compression forces to the elastomer piece. The fastening mechanisms may be fine-tuned to apply desired compression force to different portions of the elastomer pieces
Data Source
AI summary
A rotatable optical reflector device of a Light Detection and Ranging (LiDAR) scanning system used in a motor vehicle is disclosed. The rotatable optical reflector device comprises a glass-based optical reflector including a plurality of reflective surfaces and a flange. The rotatable optical reflector device further comprises a metal-based motor rotor body at least partially disposed in an inner opening of the glass-based optical reflector. The rotatable optical reflector device further comprises an elastomer piece having a first surface and a second surface. The first surface of the elastomer piece is in contact with a second mounting surface of the flange. The rotatable optical reflector device further comprises a clamping mechanism compressing the elastomer piece at the second surface of the elastomer piece, wherein movement of the metal-based motor rotor body causes the glass-based optical reflector to optically scan light in a field-of-view of the LiDAR scanning system.