A laser radar based on distributed MEMS

Abstract

A laser radar based on distributed MEMS, including a head unit of a MEMS scanning mirror, a central control subsystem and a transmission device; the head unit of the MEMS scanning mirror and the central control subsystem are connected via a transmission device. Compared with the prior art, the beneficial effects of the present invention are: a coaxial detection structure based on a MEMS scanning mirror is realized, and the detection signal-to-noise ratio of the laser radar is improved. At the same time, by sharing the central control subsystem, the cost and volume of control, laser detection and laser source are reduced, while allowing the central control subsystem to provide a unified view of the head units of all MEMS scanning mirrors, and provide the fused laser radar point cloud data to autonomous driving applications. In addition, the laser radar reflected by the present invention distinguishes between the interference light signals of other surrounding devices, reducing the interference of other operating laser radars and other nearby light sources.

Description

Technical Field

[0001] The present invention belongs to the field of laser radar, and in particular relates to a laser radar based on distributed MEMS. Background Art

[0002] At present, there are three mainstream sensors used to sense the surrounding environment: camera vision sensors, ordinary millimeter-wave radars, and lidars. Camera vision sensors can easily achieve high-resolution images, but they are easily affected by environmental and external factors, and they must rely on powerful algorithms to recognize objects in images. Ordinary millimeter-wave radars have a strong ability to penetrate fog, smoke, and dust, and are all-weather and all-day, but their detection accuracy is very limited due to their wavelength. Compared with camera vision sensors and ordinary millimeter-wave radars, lidars use infrared lasers as light sources, and determine the distance, shape, and size of objects by scanning and detecting the laser reflected from an object to form a high-precision three-dimensional map. However, existing automotive lidars, especially high-resolution lidars, are large in size, which is not conducive to integration with vehicles to provide high-resolution detection of the overall surrounding environment. Summary of the invention

[0003] To solve the above problems, an object of the present invention is to provide a distributed MEMS-based laser radar with a sensor size reduced to a minimum while providing very high-resolution enhanced capabilities for overall environment detection.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a laser radar based on distributed MEMS, comprising a head unit of a MEMS scanning mirror, a central control subsystem and a transmission device; the head unit of the MEMS scanning mirror and the central control subsystem are connected through a transmission device; the transmission device is an optical fiber transmission device or a cable transmission device; the optical fiber transmission device is composed of a collimator, a double-clad optical fiber and a combiner; the combiner is fixedly installed at the end of the double-clad optical fiber; the collimator is installed at the other end of the double-clad optical fiber.

[0005] Furthermore, the double-clad optical fiber consists of a core, an inner cladding, an outer cladding and a protective layer; the core is fixedly installed on the inner side of the inner cladding; the inner cladding is fixedly installed on the inner side of the outer cladding; and the protective layer is wound on the outer cladding.

[0006] Furthermore, the cable transmission device is composed of a receiving lens, a detection board and a receiving cable; the receiving lens and the detection board are connected; one end of the receiving cable is connected to the detection board, and the other end is connected to the central control subsystem.

[0007] Furthermore, the central control subsystem is composed of a laser source, an optical fiber splitter, a MEMS scanning mirror control unit, a reflected laser detection unit and a system control unit; the laser source, the MEMS scanning mirror control unit and the reflected laser detection unit are connected to the system control unit through wires; the laser source and the optical fiber splitter are directly connected through optical fibers.

[0008] Furthermore, the fiber core diameter is 1 micron to 10 microns.

[0009] Furthermore, the number of head units of the MEMS scanning mirror is 2-500.

[0010] Furthermore, the beam combiner is fixedly mounted on a head unit of the MEMS scanning mirror or on a central control subsystem. Preferably, the beam combiner is fixedly mounted on the central control subsystem.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: the laser radar of the present invention mainly includes a head unit of a MEMS scanning mirror and a central control subsystem. A central control subsystem can be connected to the head units of multiple MEMS scanning mirrors and provide control, laser source and reflected laser detection. By sharing the central control subsystem, the cost of control and laser source is reduced, while allowing the central control subsystem to provide a unified view of the head units of all MEMS scanning mirrors and provide fused laser radar point cloud data to autonomous driving applications. The MEMS scanning mirror in the head unit of the MEMS scanning mirror of the laser radar of the present invention has the function of transmitting laser scanning, and acts as a reflector to couple the reflected laser from the scanned object to the receiving optical fiber, realizing a coaxial detection structure based on the MEMS scanning mirror and improving the detection signal-to-noise ratio of the laser radar. The distributed MEMS laser radar of the present invention has a central control subsystem that centrally controls the head units of each MEMS scanning mirror and centrally detects the reflected laser signals of the scanned objects received by the head units of each MEMS scanning mirror. The reflected laser signals of the laser radar of the present invention can be spatially and temporally distinguished from the interfering light signals of other surrounding devices, thereby reducing the interference of other operating laser radars and other nearby light sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0013] Figure 2 It is a schematic diagram of the operation of the head unit of the MEMS scanning mirror of the present invention;

[0014] Figure 3 This is a schematic diagram of the laser radar cable receiving of the present invention;

[0015] Figure 4 A schematic diagram of a head unit of a MEMS scanning mirror of the present invention with a reflective mirror;

[0016] Figure 5 It is a schematic diagram of a cable receiving device with a reflector for a laser radar of the present invention;

[0017] Explanation of reference numerals: laser radar head unit 1, central control subsystem 2, cable transmission device 4, reflector 5, optical fiber transmission device 6, optical fiber 7, system control unit 21, MEMS scanning mirror control unit 22, reflected laser detection unit 23, laser source 24, optical fiber splitter 25, laser source optical fiber 31, receiving optical fiber 32, MEMS control line 33, receiving lens 41, detection board 42, receiving cable 43, fiber core 621, inner cladding 622, outer cladding 623, protective layer 624. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Please see attached Figures 1 to 4 As shown, a laser radar of the present invention includes a head unit 1 of a MEMS scanning mirror, a central control subsystem 2 and a transmission device, wherein the head unit 1 of the MEMS scanning mirror (the head unit of the MEMS mirror includes a MEMS reflector, an optical fiber for a laser source and an optical fiber for reflecting light) and the central control subsystem 2 are connected via the transmission device, and the transmission device is composed of an optical fiber transmission device 6 or a cable transmission device 4, and the optical fiber transmission device 6 is composed of a collimator 61, a double-clad optical fiber 62 (the double-clad optical fiber 62 is composed of a core 621, an inner cladding 622, an outer cladding 623 and a protective layer 62 4, and are sequentially sleeved from the inside to the outside) and a beam combiner 63; the beam combiner 63 is fixedly installed at the end of the double-clad optical fiber 62; the collimator 61 is installed at the other end of the double-clad optical fiber 62; the central control subsystem 2 is composed of a laser source 24, an optical fiber splitter 25, a MEMS scanning mirror control unit 22, a reflected laser detection unit 23 and a system control unit 21, and the laser source 24, the MEMS scanning mirror control unit 22 and the reflected laser detection unit 23 are connected to the system control unit 21 through wires, and the laser source 24 and the optical fiber splitter 25 are directly connected through optical fibers. Specific embodiments

[0020] The laser source 24 in the central control subsystem 2 emits a light source and transmits it to the optical fiber splitter 25. The optical fiber splitter 25 distributes the light source in a certain proportion and then transmits it to the collimator 61 through the fiber core 621 for correction and then projects it into the head unit 1 of the MEMS scanning mirror and reflects it out. When the reflected light hits an obstacle, the light source will return to the original path and re-project it onto the MEMS scanning mirror of the head unit 1 of the MEMS scanning mirror. Since the MEMS scanning mirror of the head unit 1 of the MEMS scanning mirror will rotate during operation, the reflected light source will be transported through the inner cladding of the double-clad optical fiber 62. When the reflected light source is transported to the end of the inner cladding, it will be gathered by the combiner 63 and then transmitted to the reflected laser detection unit 23 for processing. Specific embodiments

[0021] The laser source in the central control subsystem 2 emits a light source and transmits it to the optical fiber splitter 25. The light source is distributed according to a certain proportion by the optical fiber splitter 25 and then transmitted to the collimator 61 through the optical fiber 7 for correction. After that, it is projected onto the MEMS scanning mirror of the head unit 1 of the MEMS scanning mirror and reflected out. When the reflected light hits an obstacle, the reflected light source is transmitted to the detection board 42 for processing through the receiving lens 41. After the processing is completed, it is converted into an electrical signal. Finally, the electrical signal is transmitted to the central control subsystem 2 through the receiving cable 43 for final data processing to complete the entire scanning process. Specific embodiments

[0022] By adding a reflector 5 in the head unit 1 of the MEMS scanning mirror, the light source is reflected by the reflector 5 onto the MEMS scanning lens and then projected out. When the projected light source hits an obstacle, it is reflected back and transmitted to the central control subsystem 2 through the optical fiber transmission device 6 for processing.

[0023] When cable reception is used, the projected light source is reflected back when it hits an obstacle and passes through the receiving lens 41. The receiving lens 41 transmits the reflected light from the obstacle to the detection board 42 for processing. After the processing is completed, it is converted into an electrical signal. Finally, the electrical signal is transmitted to the central control subsystem 2 through the receiving cable 43 for final data processing.

[0024] The central control subsystem of the present invention can control multiple laser radar MEMS head units at the same time. The central control subsystem 2 drives the laser source 24 through electric wires and drives the MEMS scanning mirror to rotate through the MEMS scanning mirror control unit 22.

[0025] The present invention uses a coaxial receiving structure so that the laser radar can detect reflected light in a very narrow field of view angle corresponding to a specific time window to avoid most interference from other light sources.

[0026] The structure of the present invention is particularly suitable for vehicle autonomous driving and other equipment by using a minimally exposed head unit, centralizing and sharing the laser source 24, MEMS scanning mirror control unit 22, reflected laser detection unit 23 and system control unit 21.

[0027] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A laser radar based on distributed MEMS, characterized in that: The invention comprises a head unit of a MEMS scanning mirror, a central control subsystem and a transmission device; the head unit of the MEMS scanning mirror and the central control subsystem are connected via a transmission device; the transmission device is an optical fiber transmission device; the optical fiber transmission device is composed of a collimator, a double-clad optical fiber and a beam combiner; the beam combiner is fixedly mounted at the end of the double-clad optical fiber; the collimator is mounted at the other end of the double-clad optical fiber; the head unit of the MEMS mirror comprises a MEMS reflector, an optical fiber for a laser source and an optical fiber for reflecting light; the double-clad optical fiber is composed of a core, an inner cladding, an outer cladding and a protective layer; the core is fixedly mounted on the inner side of the inner cladding; the inner cladding is fixedly mounted on the inner side of the outer cladding; the protective layer covers the outer cladding; the beam combiner is fixedly mounted on the head unit of the MEMS scanning mirror or on the central control subsystem; the central control subsystem is composed of a laser source, an optical fiber splitter, a MEMS scanning mirror control unit, a reflected laser detection unit and a system control unit; the laser source, MEMS The scanning mirror control unit and the reflected laser detection unit are connected to the system control unit through wires; the laser source and the optical fiber splitter are directly connected through optical fibers; the central control subsystem simultaneously controls the head units of the MEMS scanning mirrors of multiple laser radars; and the central control subsystem drives the laser source through electric wires, and drives the MEMS scanning mirror to rotate through the MEMS scanning mirror control unit. The beam combiner is used to gather the light source when the light source is reflected back when it hits an obstacle after being projected through the fiber core and is transmitted to the end of the inner cladding through the beam combiner.

2. A laser radar based on distributed MEMS according to claim 1, characterized in that The fiber core diameter is 1 micron to 60 microns.

3. The laser radar based on distributed MEMS according to claim 1, characterized in that The number of head units of the MEMS scanning mirror is 2-500.

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