Vehicle-mounted lidar (LiDAR, Light Detection and Ranging) is one of the key perception systems in autonomous vehicles. It measures the distance and shape of surrounding objects by emitting laser pulses and receiving reflected signals from objects, thereby generating a high-precision three-dimensional environment map. Among them, the scanning galvanometer is a key component in vehicle-mounted lidar used to control the direction of the laser beam. It is responsible for adjusting the scanning angle of the laser beam so that it can cover the required field of view, thereby obtaining the three-dimensional point cloud data required for the environment. Compared with cameras and radars, lidar can provide high-resolution spatial perception capabilities under various lighting conditions and therefore plays an irreplaceable role in the development of autonomous driving technology.
Optical components for automotive lidar
Laser emitter: Semiconductor lasers with wavelengths of 905nm or 1550nm are usually used. Lasers with these wavelengths are invisible to the human eye and have high energy, making them suitable for long-distance detection.
Optical lens: used to focus or expand the laser beam to ensure that the laser pulse can cover the required field of view and be effectively transmitted to the target area.
Optical filter (optical filter): used to filter out background noise and only allow laser signals of specific wavelengths to pass through to improve the signal-to-noise ratio.
Photodetector: used to receive reflected laser signals, usually using avalanche photodiodes (APD) or photomultiplier tubes (PMT) to improve sensitivity and detection range
The principle of scanning galvanometer in vehicle-mounted lidar
The scanning galvanometer is usually driven by a high-speed motor or a piezoelectric actuator to change the direction of the laser beam by controlling the angle of the mirror. The galvanometer can achieve a variety of scanning modes, such as linear scanning, zigzag scanning or spiral scanning, to meet different application needs.
1. Linear scanning: Suitable for progressive scanning in horizontal and vertical directions, which can generate high-resolution two-dimensional or three-dimensional images.
2. Zigzag scanning: By continuously adjusting the scanning direction, a larger field of view can be covered.
3. Spiral scanning: used for all-round scanning, suitable for 3D modeling and panoramic imaging.
Advantages of scanning galvanometers
In vehicle-mounted lidar, the scanning galvanometer has the characteristics of high precision, strong flexibility, small size, light weight, and high reliability. The precise angle and direction control of the laser beam ensures high accuracy and high resolution of the detection results. The highly flexible scanning range and mode can adapt to different driving environments and application scenarios. The design for the development of vehicle-mounted lidar is tight.
It is compact and can provide excellent performance without increasing the burden on the system. After optimized design, it can withstand various harsh environments such as extreme temperatures, vibrations and humidity, ensuring the long-term stability and durability of the system.
Therefore, the vehicle-mounted lidar scanning galvanometer is of great significance in the entire vehicle scanning. It not only determines the field of view coverage, resolution and accuracy of the lidar, but also improves the flexibility and response speed of the system. Therefore, the selection of the vehicle-mounted lidar scanning galvanometer needs to pay more attention to its quality and technical conditions, which will directly affect the overall safety and efficiency of the autonomous driving system.
