Optical passive rotary laser radar and control method
By adopting an optical passive design in 360° rotating lidar, optical transmission between the array waveguide grating chip and the frequency modulated continuous wave radar chip is solved, and the system reliability and measurement accuracy are improved.
Patent Information
- Application Number
- CN202411862402.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-17
- Publication Date
- 2025-05-06
AI Technical Summary
The existing 360° rotating lidar has low reliability due to brush wear and poor electrical contact problems.
The optical passive rotary lidar design is adopted to transmit signal light and reflected light through the electrical connection between the array waveguide grating chip and the frequency modulated continuous wave radar chip.
It greatly improves the stability and reliability of the lidar, avoids brush wear and poor electrical contact problems, and enhances the durability and measurement accuracy of the system.
Smart Images
Figure CN119936836A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of laser radar technology, and in particular to an optical passive rotating laser radar and a control method thereof. Background Art
[0002] The 360° rotating LiDAR system is an advanced and critical sensing technology that has been widely used in many fields in recent years, including autonomous driving, robot navigation, geographic information systems, and environmental monitoring. The basic working principle of this system is to accurately measure the distance between the object and the sensor by emitting a laser beam and receiving the light signal reflected from the surrounding objects.
[0003] The LiDAR system contains a laser transmitter that emits laser pulses at a specific frequency. The laser and receiver are usually mounted on a rotating platform, which can achieve 360° full-range scanning. When the laser pulse is emitted, it will be reflected when it encounters surrounding objects. The reflected light signal is received by the photodetector, and the system measures the time interval from the laser emission to the reception of the reflected signal, and uses the speed of light to calculate the distance between the object and the sensor. By repeating this process continuously, LiDAR can quickly obtain a large number of data points and then build a high-precision three-dimensional environment model.
[0004] In the current 360° rotating LiDAR design, the commonly used solution is to integrate multi-channel transmitting (Tx) and receiving (Rx) optoelectronic chips, lenses and some control circuits on the same rotating platform to achieve continuous rotation around the axis. Although this integrated design has certain advantages in improving the compactness and functionality of the system, all its electrical connections rely on crimped brushes for signal transmission. This method significantly increases the number of connection points when the number of channels increases, thereby increasing the complexity of the system. This not only makes the contact surface easy to wear, oxidize or be contaminated, but also causes poor contact and signal attenuation problems, affecting the performance and reliability of the LiDAR.
[0005] In summary, the current 360° rotating laser radar needs to use brushes to electrically connect the devices on the rotating module. Long-term use will cause brush wear and poor electrical contact, resulting in reduced reliability of the 360° rotating laser radar. Summary of the invention
[0006] In view of this, the present invention provides an optical passive rotating laser radar and a control method to solve or partially solve the technical problem of low reliability of existing 360° rotating laser radars.
[0007] The technical solution proposed by the present invention is as follows:
[0008] A first aspect of the present invention provides an optical passive rotating laser radar, comprising a rotating module and a fixed module, wherein the rotating module and the fixed module are arranged separately and the rotating module can rotate relative to the fixed module on a preset rotating plane;
[0009] The rotating module includes an arrayed waveguide grating chip, a first optical path adjustment component and a second optical path adjustment component, and the fixed module includes a tunable laser, a frequency modulated continuous wave radar chip and a third optical path adjustment component;
[0010] Tunable lasers are used to output signal lights of several different wavelengths;
[0011] The frequency modulated continuous wave radar chip is used to output the signal light output by the tunable laser to the arrayed waveguide grating chip through the second optical path adjustment component and the third optical path adjustment component;
[0012] The second optical path adjustment component and the third optical path adjustment component are used to cooperate with each other to converge the signal light output by the frequency modulated continuous wave radar chip to the incident port of the arrayed waveguide grating chip;
[0013] The arrayed waveguide grating chip is used to output signal lights of different wavelengths to the first optical path adjustment component through different output ports. The signal lights of different wavelengths respectively scan different target areas after passing through the first optical path adjustment component, receive reflected light returned from the target area through the first optical path adjustment component, and output the reflected light to the second optical path adjustment component. The reflected light passes through the second optical path adjustment component and the third optical path adjustment component in turn and then enters the frequency modulated continuous wave radar chip. The frequency modulated continuous wave radar chip calculates the object distances of different target areas according to the received reflected light.
[0014] An optical passive rotating laser radar of the present invention uses an array waveguide grating chip and a first optical path adjustment component in a rotating module to scan different target areas with signal lights of different wavelengths and receive returned reflected light, and transmits the signal light and reflected light between the array waveguide grating chip and the frequency modulated continuous wave radar chip through the second optical path adjustment component and the third optical path adjustment component. The array waveguide grating chip in the rotating module and the frequency modulated continuous wave radar chip in the fixed module do not need to be electrically connected, thereby avoiding brush wear and poor electrical contact problems in long-term use, thereby greatly improving the stability and reliability of the laser radar in long-term operation.
[0015] In an optional embodiment, the first optical path adjustment component includes a first collimating lens, the output port of the array waveguide grating chip is located on the focal plane of the first collimating lens, and the first collimating lens is used to converge the signal light output by the array waveguide grating chip into a parallel light beam, and to converge the reflected light returned from the target area to the output port of the array waveguide grating chip.
[0016] In this way, the output port of the arrayed waveguide grating chip is located on the focal plane of the first collimating lens, which can effectively converge the signal light into a parallel light beam, and at the same time converge the reflected light to the output port of the arrayed waveguide grating chip, thereby improving the collimation efficiency of the light beam and the stability of the optical path, thereby improving the overall performance of the optical passive rotating lidar.
[0017] In an optional embodiment, the second optical path adjustment component includes a second collimating lens, and the third optical path adjustment component includes a third collimating lens; the second collimating lens is used to converge the signal light emitted through the third collimating lens to the incident port of the array waveguide grating chip, and to converge the reflected light output through the array waveguide grating chip into a parallel light beam and then output it to the third collimating lens; the third collimating lens is used to converge the parallel light beam emitted through the second collimating lens to the receiving end of the frequency modulated continuous wave radar chip, and to converge the signal light output from the frequency modulated continuous wave radar chip into a parallel light beam and then output it to the second collimating lens.
[0018] In this manner, the transmission of the signal light and the reflected light in the rotating module and the fixed module is achieved through the cooperation of the second collimating lens and the third collimating lens, thereby reducing the loss of the light beam during the transmission process.
[0019] In an optional implementation, the arrayed waveguide grating chip, the second collimating lens, the third collimating lens and the frequency modulated continuous wave radar chip are sequentially arranged along a rotation axis perpendicular to a preset rotation plane.
[0020] In this way, the arrayed waveguide grating chip, the second collimating lens, the third collimating lens and the frequency-modulated continuous wave radar chip are arranged in sequence on the rotating axis. This layout can effectively utilize space, eliminates the need to deflect the light, simplifies the optical path design, and reduces the volume and weight of the optical passive rotating laser radar.
[0021] In an optional implementation, two first optical path adjustment components are provided, and the two first optical path adjustment components are respectively installed on two opposite sides of the arrayed waveguide grating chip.
[0022] In this manner, first optical path adjustment components are provided on opposite sides of the arrayed waveguide grating chip to achieve signal light output in two directions, balance the center of gravity of the system during rotation, reduce vibration, and improve mechanical stability.
[0023] In an optional implementation, the signal light output by the tunable laser is signal light of different wavelength bands with a wavelength interval of 0.4 nm or 0.3 nm.
[0024] In this manner, the wavelength interval of the signal light is set to 0.4 nm or 0.3 nm, thereby reducing the wavelength range required to be output by the tunable laser, thereby reducing the cost of the selected tunable laser.
[0025] In an optional implementation, the number of wavelength bands of the signal light is 126.
[0026] In this method, the signal light has 126 wavelength bands, which can be used for fine spectrum segmentation, thus improving the accuracy and reliability of the measurement.
[0027] In an optional implementation, the rotation angle of the rotating module is 360°.
[0028] In this way, the optical passive rotating laser radar can achieve full-angle scanning, which improves the monitoring range of the optical passive rotating laser radar and enables it to be used in a wider range of application scenarios.
[0029] In an optional implementation, both the arrayed waveguide grating chip and the frequency modulated continuous wave radar chip are photonic integrated circuit chips.
[0030] In this way, the overall volume and weight of the optical passive rotating lidar can be reduced.
[0031] The second aspect of the present invention provides a control method for an optical passive rotating laser radar, which is applied to the optical passive rotating laser radar according to the first aspect of the present invention and any one of the first aspects, comprising:
[0032] Controlling the tunable laser to output a plurality of signal lights of different wavelengths in sequence based on a time sequence;
[0033] Controlling the rotating module to rotate relative to the fixed module on a preset rotating plane so that signal lights of different wavelengths scan different target areas respectively;
[0034] The reflected light returned from the target area is received by the frequency-modulated continuous wave radar chip, and the distance of objects in different target areas is calculated based on the frequency difference between the reflected light and the corresponding signal light. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] In order to more clearly express the technical solutions of the embodiments of the present invention, the drawings required for describing the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0036] Figure 1 It is a structural block diagram of an optical passive rotating laser radar in an embodiment of the present invention;
[0037] Figure 2 Flow chart of a control method for an optical passive rotating laser radar in an embodiment of the present invention.
[0038] Reference numerals:
[0039] 1-rotating module; 2-fixed module; 11-arrayed waveguide grating chip; 12-first optical path adjustment component; 13-second optical path adjustment component; 21-third optical path adjustment component; 22-frequency modulated continuous wave radar chip; 23-tunable laser. DETAILED DESCRIPTION
[0040] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. 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.
[0041] In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.
[0042] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0043] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
[0044] In the current 360° rotating LiDAR design, the commonly used solution is to integrate multi-channel transmitting (Tx) and receiving (Rx) optoelectronic chips, lenses and some control circuits on the same rotating platform to achieve continuous rotation around the axis. Although this integrated design has certain advantages in improving the compactness and functionality of the system, it brings two major engineering challenges.
[0045] First, all electrical connections rely on crimped brushes for signal transmission. This method significantly increases the number of connection points as the number of channels increases, which in turn increases the complexity of the system. This not only makes the contact surface prone to wear, oxidation or contamination, but also causes poor contact and signal attenuation problems, affecting the performance and reliability of the lidar. Therefore, research on more robust connection solutions, such as brushless electrical connection technology, has become the key to improving system reliability.
[0046] Secondly, due to the large number of integrated components, the overall weight of the rotating platform increases significantly, which has a negative impact on the dynamic response and long-term stability of the rotating system. The rotating platform may cause mechanical fatigue and vibration during rotation, further affecting the accuracy of laser ranging and the stability of data acquisition. Therefore, optimizing the component layout and using lightweight materials and advanced manufacturing processes to reduce the weight of the rotating platform have become issues that need to be urgently addressed in the design.
[0047] In summary, although the 360° rotating lidar has certain advantages in integration, in-depth research and innovation are still needed in the reliability of electrical connections and weight management of the rotating platform to improve its overall performance and feasibility of practical application.
[0048] like Figure 1 As shown, an embodiment of the present invention provides an optical passive rotating laser radar, including a rotating module 1 and a fixed module 2, wherein the rotating module 1 and the fixed module 2 are arranged separately and the rotating module 1 can rotate relative to the fixed module 2 on a preset rotation plane.
[0049] Specifically, the rotating module 1 is arranged on a rotating platform, and the rotating platform is controlled by a computer to rotate, thereby driving various components in the rotating module 1 to rotate.
[0050] The rotating module 1 includes an arrayed waveguide grating chip 11 , a first optical path adjustment component 12 and a second optical path adjustment component 13 , and the fixing module 2 includes a tunable laser 23 , a frequency modulated continuous wave radar chip 22 and a third optical path adjustment component 21 .
[0051] Arrayed Waveguide Grating (AWG) chip and Frequency Modulated Continuous Wave Laser Radar (FMCW) chip are both photonic integrated circuit (PIC) chips. Photonic integrated circuit chips are small in size and low in weight, which can reduce the overall size and weight of optical passive rotating laser radar.
[0052] The arrayed waveguide grating chip 11 is the core component of the optical passive rotating laser radar, which has an input port and multiple output ports, and can achieve selective output of different input wavelengths. Signal lights of different wavelengths are emitted through the corresponding output ports, and the emission points are located on the focal plane of the first optical path adjustment component 12. After being collimated by the first optical path adjustment component 12, the signal lights are directed to different directions, thereby scanning different target areas.
[0053] The tunable laser 23 is used to output signal lights of several different wavelengths.
[0054] The tunable laser 23 is responsible for emitting laser beams of different wavelengths, namely, signal light. The arrayed waveguide grating chip 11 will frequency modulate the emitted laser beams, and scan different target areas through signal lights of different wavelengths.
[0055] Specifically, the tunable laser 23 emits a beam of signal light, and the wavelength of the signal light can be precisely tuned by electronic control. In one example, the wavelength interval is designed to be 0.4nm, and the output signal light is divided into 128 bands according to the wavelength, meeting the requirements of dense wavelength division multiplexing communication, so that the wavelength range covered by 128 channels is 51.2nm, and the signal light of each band is emitted through the output port corresponding to the arrayed waveguide grating chip 11.
[0056] The frequency modulated continuous wave radar chip 22 is used to output the signal light output by the tunable laser 23 to the arrayed waveguide grating chip 11 through the second optical path adjustment component 13 and the third optical path adjustment component 21 .
[0057] The second optical path adjustment component 13 and the third optical path adjustment component 21 are used to cooperate with each other to converge the signal light output by the FMCW radar chip 22 to the incident port of the arrayed waveguide grating chip 11 .
[0058] The tuned signal light is emitted to the second optical path adjustment component 13 through the frequency modulated continuous wave radar chip 22 , and is respectively collimated and converged by the second optical path adjustment component 13 and the third optical path adjustment component 21 , and then transmitted to the incident port of the arrayed waveguide grating chip 11 .
[0059] The first optical path adjustment component 12, the second optical path adjustment component 13 and the third optical path adjustment component 21 can all adopt a single convex lens or a single meniscus lens, or a combination of multiple convex lenses and meniscus lenses.
[0060] The arrayed waveguide grating chip 11 is used to output signal lights of different wavelengths to the first optical path adjustment component 12 through different output ports. The signal lights of different wavelengths scan different target areas respectively after passing through the first optical path adjustment component 12, receive reflected light returned from the target area through the first optical path adjustment component 12, and output the reflected light to the second optical path adjustment component 13. The reflected light passes through the second optical path adjustment component 13 and the third optical path adjustment component 21 in turn and then enters the frequency modulated continuous wave radar chip 22. The frequency modulated continuous wave radar chip 22 calculates the object distances of different target areas according to the received reflected light.
[0061] Specifically, when the signal light output by the array waveguide grating chip 11 encounters an object in the surrounding environment, part of the light will be reflected back by the object, and the reflected light still maintains the collimated direction, returns to the first optical path adjustment component 12 and is received through the same output port of the array waveguide grating chip 11. The reflected light is received coaxially with the signal light to ensure the integrity of the signal quality.
[0062] The reflected light passes through the second optical path adjustment component 13 and the third optical path adjustment component 21 and enters the frequency modulated continuous wave radar chip 22 for processing, and the integrity and transmission efficiency of the optical signal are ensured through the passive optical design.
[0063] Since the frequency of the signal light output by the tunable laser 23 changes with time (usually linearly), when the signal light is reflected by an object and returns, the FMCW radar chip 22 compares the received reflected light with the signal light and analyzes the frequency difference between the two. The object distance is calculated based on the frequency difference. According to the principle of FMCW, the relationship between the frequency difference and the target distance is:
[0064]
[0065] Where c is the speed of light, K f is the slope of the frequency modulation (i.e., the rate at which the frequency changes over time). Δf represents the frequency difference between the reflected light and the signal light. By measuring the frequency difference, the FMCW radar chip 22 can calculate the distance of the target object in real time and perform three-dimensional modeling based on the strength and time difference of the return signal.
[0066] Furthermore, the FMCW radar chip 22 performs real-time analysis on the reflected light of each wavelength to calculate the target distance and relative speed. After each round of scanning, the FMCW radar chip 22 aggregates the accumulated data points to generate a high-resolution three-dimensional point cloud map, which displays the distribution of objects in the environment through a computer.
[0067] An optical passive rotating laser radar according to an embodiment of the present invention uses an arrayed waveguide grating chip 11 and a first optical path adjustment component 12 in a rotating module 1 to scan different target areas with signal lights of different wavelengths and receive returned reflected light, and transmits the signal light and reflected light between the arrayed waveguide grating chip 11 and the frequency modulated continuous wave radar chip 22 through the second optical path adjustment component 13 and the third optical path adjustment component 21. The arrayed waveguide grating chip 11 in the rotating module 1 and the frequency modulated continuous wave radar chip 22 of the fixed module 2 do not need to be electrically connected, thereby avoiding brush wear and poor electrical contact problems during long-term use, thereby greatly improving the stability and reliability of the laser radar in long-term operation.
[0068] In an optional embodiment, the first optical path adjustment component 12 includes a first collimating lens, and the output port of the array waveguide grating chip 11 is located on the focal plane of the first collimating lens. The first collimating lens is used to converge the signal light output by the array waveguide grating chip 11 into a parallel light beam, and to converge the reflected light returned from the target area to the output port of the array waveguide grating chip 11.
[0069] Specifically, the first collimating lens is a high-precision convex lens or a meniscus lens, and the light emitted from or received by the output port of the arrayed waveguide grating chip 11 needs to pass through the first collimating lens.
[0070] The light emitted from the output port of the arrayed waveguide grating chip 11 is converted from a dispersed light beam to a parallel light beam after passing through the first collimating lens, which can ensure that the emission direction of the optical signal has extremely high accuracy, and can also effectively reduce the beam divergence angle and improve the detection range.
[0071] At the same time, the signal light corresponding to each wavelength can be irradiated in different directions after being collimated by the lens, achieving 360° all-round coverage.
[0072] When the laser beam is reflected back by the object, the reflected light signal passes through the first collimating lens and is received by the same output port of the arrayed waveguide grating chip 11. The reflected light and the signal light are received coaxially to ensure the integrity of the signal quality.
[0073] In this way, the output port of the arrayed waveguide grating chip 11 is located on the focal plane of the first collimating lens, which can effectively converge the signal light into a parallel light beam, and at the same time converge the reflected light to the output port of the arrayed waveguide grating chip 11, thereby improving the collimation efficiency of the light beam and the stability of the optical path, thereby improving the overall performance of the optical passive rotating laser radar.
[0074] In an optional embodiment, the second optical path adjustment component 13 includes a second collimating lens, and the third optical path adjustment component 21 includes a third collimating lens; the second collimating lens is used to converge the signal light emitted through the third collimating lens to the incident port of the array waveguide grating chip 11, and to converge the reflected light output through the array waveguide grating chip 11 into a parallel light beam and then output it to the third collimating lens; the third collimating lens is used to converge the parallel light beam emitted through the second collimating lens to the receiving end of the frequency modulated continuous wave radar chip 22, and to converge the signal light output from the frequency modulated continuous wave radar chip 22 into a parallel light beam and then output it to the second collimating lens.
[0075] Specifically, the second collimating lens and the third collimating lens adopt high-precision convex lens or meniscus lens. Through the cooperation of the second collimating lens and the third collimating lens, the transmission of signal light and reflected light in the rotating module 1 and the fixed module 2 is realized, reducing the loss of light beam during transmission.
[0076] In an optional implementation, the arrayed waveguide grating chip 11, the second collimating lens, the third collimating lens and the frequency modulated continuous wave radar chip 22 are sequentially arranged along a rotation axis perpendicular to a preset rotation plane.
[0077] Specifically, the rotating module 1 rotates around the rotating axis on the rotating platform, so on the rotating axis, the center points of the array waveguide grating chip 11, the second collimating lens, the third collimating lens and the frequency modulated continuous wave radar chip 22 are relatively unchanged. Based on this, the optical path transmission between the array waveguide grating chip 11 and the frequency modulated continuous wave radar chip 22 is not affected while the rotating module 1 rotates.
[0078] At the same time, the arrayed waveguide grating chip 11, the second collimating lens, the third collimating lens and the frequency-modulated continuous wave radar chip 22 are arranged in sequence on the rotating axis. This layout can effectively utilize space, eliminates the need to deflect light, simplifies the optical path design, and reduces the volume and weight of the optical passive rotating laser radar.
[0079] In an optional implementation, two first optical path adjustment components 12 are provided, and the two first optical path adjustment components 12 are respectively installed on two opposite sides of the arrayed waveguide grating chip 11 .
[0080] Specifically, the first optical path adjustment components 12 on the opposite sides of the arrayed waveguide grating chip 11 rotate around the rotation axis at the same time. For example, the two first optical path adjustment components 12 are respectively installed on the left and right sides of the arrayed waveguide grating chip 11, or the two first optical path adjustment components 12 are respectively installed on the front and rear sides of the arrayed waveguide grating chip 11. Such an arrangement can balance the center of gravity of the rotating module 1 during rotation, reduce vibration, and improve mechanical stability.
[0081] At the same time, the design can further flexibly adjust the component layout to adapt to different application scenarios and needs.
[0082] In an optional implementation, the signal light output by the tunable laser 23 is signal light of different wavelength bands with a wavelength interval of 0.4 nm or 0.3 nm.
[0083] Specifically, the wavelength interval of the signal light does not need to be too large, but in optical communication, a wavelength interval of 50 or 100 GHz (i.e., 0.4 or 0.8 nm) is usually used in the C band for dense wavelength division multiplexing communication. The signal light band can be set to 126 according to the number of output ports of the arrayed waveguide grating chip 11. Calculated at an interval of 0.4 nm, the wavelength range corresponding to 128 channels is only 51.2 nm, which is usually coverable for a single tunable laser 23. In addition, in order to reduce the system cost, it can be considered to appropriately reduce the wavelength interval to 0.3 nm, thereby reducing the wavelength range to 40 nm, thereby achieving compatibility with a lower-cost tunable laser 23, allowing the use of a lower-cost tunable laser 23, and still maintaining high-precision environmental perception capabilities, thereby reducing the cost of the selected tunable laser 23.
[0084] In addition, due to the narrow wavelength range, the dispersion effect of the lens is weak in a small range, so the dispersion will not significantly affect the signal quality. This further improves the optical performance and measurement accuracy of the lidar.
[0085] In an optional embodiment, the rotation angle of the rotating module 1 is 360°.
[0086] Specifically, the rotating module 1 is arranged on a rotating platform, and the rotating platform can be driven to rotate by a motor, and its rotation angle is 360°, so that the optical passive rotating laser radar can achieve full-angle scanning, thereby improving the monitoring range of the optical passive rotating laser radar and enabling it to be applied to a wider range of application scenarios.
[0087] The embodiment of the present invention further provides a control method for an optical passive rotating laser radar, which is applied to the optical passive rotating laser radar in any of the above embodiments, such as Figure 2 As shown, the control method includes:
[0088] Step S201, controlling the tunable laser 23 to output a plurality of signal lights of different wavelengths in sequence based on a time sequence;
[0089] Step S202, controlling the rotating module 1 to rotate relative to the fixed module 2 on a preset rotating plane, so that the signal lights of different wavelengths scan different target areas respectively;
[0090] Step S203 , receiving the reflected light returned from the target area by the FMCW radar chip 22 , and calculating the object distances of different target areas based on the frequency difference between the reflected light and the corresponding signal light.
[0091] The control method of the optical passive rotating laser radar can be executed in a computer device. By controlling the rotation speed of the rotating module 1 and the output laser frequency of the tunable laser 23, each round of rotation can enable signal lights of different wavelengths to scan specific target areas respectively, thereby realizing the measurement of the distance to the object.
[0092] The passive optical rotating laser radar and control method of the embodiment of the present invention adopts passive optical components and photonic integrated circuit technology to avoid electrical connection, thereby greatly improving the durability, stability and detection accuracy of the system. The passive optical rotating laser radar has the following advantages:
[0093] 1. In the rotating module 1, the arrayed waveguide grating chip 11 and the first optical path adjustment component 12 are used to scan different target areas with signal lights of different wavelengths and receive the returned reflected light, and the signal light and the reflected light are transmitted between the arrayed waveguide grating chip 11 and the frequency modulated continuous wave radar chip 22 through the second optical path adjustment component 13 and the third optical path adjustment component 21. The arrayed waveguide grating chip 11 in the rotating module 1 and the frequency modulated continuous wave radar chip 22 of the fixed module 2 do not need to be electrically connected, avoiding the problem of brush wear and poor electrical contact in long-term use, greatly improving the stability and reliability of the system in long-term operation. It also reduces the inertial force generated during high-speed rotation and reduces component loss.
[0094] 2. Through optical lenses and coaxial transmission such as the first optical path adjustment component 12, the second optical path adjustment component 13 and the third optical path adjustment component 21, the signal docking between the rotating module 1 and the fixed module 2 no longer relies on complex electrical connections, and the optical signal can be transmitted losslessly, reducing the loss and interference in the signal transmission, thereby improving the measurement performance of the system.
[0095] 3. The wavelength interval is appropriately reduced to 0.3nm, so that the wavelength range is reduced to 40nm, which can reduce the cost of the selected tunable laser 23. In addition, due to the narrow wavelength range, the dispersion effect of the lens is weak in a small range, so the dispersion will not significantly affect the signal quality. This further improves the optical performance and measurement accuracy of the laser radar.
[0096] 4. The two first optical path adjustment components 12 are respectively installed on the opposite sides of the arrayed waveguide grating chip 11, which can balance the center of gravity of the rotating module 1 during rotation, reduce vibration, and improve mechanical stability. At the same time, the design can further flexibly adjust the component layout to adapt to different application scenarios and needs.
[0097] The optical passive rotating laser radar and control method of the embodiment of the present invention not only improves the reliability of the laser radar, but also enhances the performance and application potential of the laser radar, providing new ideas and directions for future laser detection technology. Through the innovative application of passive optical design and photonic integrated circuits, the stability and reliability of the 360° mechanical rotating laser radar can be greatly improved. In the future, with the further development of photonic integrated circuit chip technology and the reduction of costs, this design is expected to be more widely used in multiple fields such as autonomous driving, drone navigation, and urban planning. At the same time, the integration of frequency modulated continuous wave radar technology will further improve the measurement accuracy and environmental perception capabilities of the laser radar, laying a solid technical foundation for achieving more intelligent and safe autonomous driving.
[0098] Although example embodiments and their advantages have been described in detail, those skilled in the art may make various changes, substitutions and modifications to these embodiments without departing from the spirit and defined scope of the present invention, and such modifications and variations are all within the defined scope.
Claims
1. An optical passive rotating laser radar, characterized in that: It comprises a rotating module and a fixed module, wherein the rotating module and the fixed module are arranged separately and the rotating module can rotate relative to the fixed module on a preset rotating plane; The rotating module includes an arrayed waveguide grating chip, a first optical path adjustment component and a second optical path adjustment component, and the fixed module includes a tunable laser, a frequency modulated continuous wave radar chip and a third optical path adjustment component; The tunable laser is used to output signal lights of several different wavelengths; The frequency modulated continuous wave radar chip is used to output the signal light output by the tunable laser to the arrayed waveguide grating chip through the second optical path adjustment component and the third optical path adjustment component; The second optical path adjustment component and the third optical path adjustment component are used to cooperate with each other to converge the signal light output by the frequency modulated continuous wave radar chip to the incident port of the arrayed waveguide grating chip; The arrayed waveguide grating chip is used to output signal lights of different wavelengths to the first optical path adjustment component through different output ports. The signal lights of different wavelengths respectively scan different target areas after passing through the first optical path adjustment component, receive reflected light returned from the target area through the first optical path adjustment component, and output the reflected light to the second optical path adjustment component. The reflected light passes through the second optical path adjustment component and the third optical path adjustment component in sequence and then enters the frequency modulated continuous wave radar chip. The frequency modulated continuous wave radar chip calculates the object distances of different target areas according to the received reflected light.
2. The optical passive rotating laser radar according to claim 1, characterized in that: The first optical path adjustment component includes a first collimating lens, the output port of the array waveguide grating chip is located on the focal plane of the first collimating lens, and the first collimating lens is used to converge the signal light output by the array waveguide grating chip into a parallel light beam, and to converge the reflected light returned from the target area to the output port of the array waveguide grating chip.
3. The optical passive rotating laser radar according to claim 1, characterized in that: The second optical path adjustment component includes a second collimating lens, and the third optical path adjustment component includes a third collimating lens; The second collimating lens is used to converge the signal light emitted by the third collimating lens to the incident port of the arrayed waveguide grating chip, and to converge the reflected light output by the arrayed waveguide grating chip into a parallel light beam and then output it to the third collimating lens; The third collimating lens is used to converge the parallel light beam emitted by the second collimating lens to the receiving end of the FMCW radar chip, and converge the signal light output by the FMCW radar chip into a parallel light beam and then output it to the second collimating lens.
4. The optical passive rotating laser radar according to claim 3, characterized in that: The arrayed waveguide grating chip, the second collimating lens, the third collimating lens and the frequency modulated continuous wave radar chip are arranged in sequence along a rotation axis perpendicular to the preset rotation plane.
5. The optical passive rotating laser radar according to claim 1, characterized in that: Two first optical path adjustment components are provided, and the two first optical path adjustment components are respectively installed on two opposite sides of the arrayed waveguide grating chip.
6. The optical passive rotating laser radar according to claim 1, characterized in that: The signal light output by the tunable laser is signal light of different wavelength bands with a wavelength interval of 0.4nm or 0.3nm.
7. The optical passive rotating laser radar according to claim 6, characterized in that: The signal light has 126 wavelength bands.
8. The optical passive rotating laser radar according to claim 1, characterized in that: The rotation angle of the rotating module is 360°.
9. The optical passive rotating laser radar according to claim 1, characterized in that: The arrayed waveguide grating chip and the frequency modulated continuous wave radar chip are both photonic integrated circuit chips.
10. A control method for an optical passive rotating laser radar, applied to the optical passive rotating laser radar according to any one of claims 1 to 9, characterized in that: include: Controlling the tunable laser to output a plurality of signal lights of different wavelengths in sequence based on a time sequence; Controlling the rotating module to rotate relative to the fixed module on a preset rotating plane so that signal lights of different wavelengths scan different target areas respectively; The reflected light returned from the target area is received by the frequency-modulated continuous wave radar chip, and the distance of objects in different target areas is calculated based on the frequency difference between the reflected light and the corresponding signal light.