FMCW LiDAR and scanning method for it

Abstract

FMCW LiDAR comprising a transceiver, a beam modifier, a scanner, and a controller, wherein the transceiver has multiple terminals arranged at least along a first direction; wherein the transceiver is configured to emit a detection light at a predetermined time sequence and to receive an echo of the detection light reflected from an object; wherein the beam modifier is configured to collimate the detection light and converge the echo onto the transceiver; wherein the scanner is configured to rotate about an axis to reflect the detection light from the beam modifier into a target space and to reflect the echo back to the beam modifier; wherein the controller is electrically connected to the scanner and configured to control the scanner to switch between multiple scanning modes;The scanner exhibits different rotational speeds and / or vibration amplitudes in different scanning modes. Terminals adjacent in time emit the detection light within the same predetermined time interval.

Description

[0001] The present application claims priority over Chinese patent application No. 202211597331.9, filed on December 12, 2022, the contents of which are hereby incorporated in their entirety by reference. TECHNICAL AREA

[0002] The present disclosure relates to the field of LiDAR technology, in particular FMCW LiDARs and scanning methods for FMCW LiDARs. BACKGROUND

[0003] A frequency-modulated continuous-wave (FMCW) LiDAR emits a frequency-modulated continuous-wave laser as detection light. A frequency shift can occur between an echo signal reflected from an object (e.g., an obstacle or barrier) and the corresponding light signal. By measuring this frequency shift, the object's distance and velocity can be determined. Typically, FMCW LiDARs use scanning mirrors. The laser beam emitted by the laser is deflected by the rotating scanning mirror, enabling scanning within a specific field of view (FOV).

[0004] The detection light beams exit the LiDAR at different angles. The greater the distance from the LiDAR, the greater the distance between detection light beams at different angles. This leads to a reduction in the LiDAR's resolution for distant targets. The number of points representing distant targets in the point cloud is very small or even zero. For example, if a tire (e.g., with a width of approximately 195 mm and a diameter of approximately 800 mm) is lying on the road surface 250 m away on a highway, and the point cloud resolution is less than 0.2° in both the horizontal and vertical directions, the tire can form a maximum of two points in the point cloud. However, these two points are insufficient for target classification and detection. The probability of detecting the tire is low.

[0005] Furthermore, the scanning speed of the mirror can be increased to enlarge the field of view (FOV). When light reflected from a distant target reaches the LiDAR, the mirror has already rotated a certain angle. The focus position, after the echo radiation has been focused by the optical components, can shift. This shift angle can be referred to as the delay angle. The faster the mirror rotates, the larger the delay angle can be. This can reduce the energy of the echo radiation. The signal-to-noise ratio and the long-range measurement capability can also be reduced. Therefore, the long-range measurement capability of the FMCW LiDAR can be negatively correlated with the scanning speed. For example, at a fixed scanning frequency, the measurement range decreases as the field of view increases. SUMMARY

[0006] In a first aspect, the present disclosure provides an FMCW LiDAR. The FMCW LiDAR comprises a transmit / receive device, a beamforming device, a scanning device, and a control device. The transmit / receive device includes multiple (e.g., a plurality of) ports arranged at least along a first direction. The transmit / receive device is configured to emit a detection light in a predetermined time sequence and to receive an echo of the detection light reflected from an object. The beamforming device is configured to collimate the detection light and converge the echo onto the transmit / receive device. The scanning device is configured to rotate about at least one axis to reflect the detection light from the beamforming device to a target space and to reflect the echo back to the beamforming device.The control device is electrically connected to the scanning device and is designed to control the scanning device by switching between multiple (e.g., a plurality of) scanning modes. The scanning device exhibits different rotational speeds and / or vibration amplitudes in different scanning modes. Terminals adjacent in time emit the detection light at a predetermined time interval.

[0007] Optionally, the multiple connections are designed to emit the detection light sequentially within the specified time interval.

[0008] Optionally, the multiple connections are divided into several (e.g., a multitude of) groups, and the respective groups of connections emit the detection light sequentially within the specified time interval.

[0009] Optionally, the scanning device has a first axis, which rotates around it to reflect the detection light at different angles in a first plane. The first axis is parallel to the first direction, and the first plane is perpendicular to the first direction.

[0010] Optionally, the vibration amplitude of the scanning device corresponds to a range for the field of view angle of the FMCW LiDAR in the first plane.

[0011] Optionally, the rotational speed of the scanning device is related to a range for the field of view angle (FOV angle) of the FMCW LiDAR in the first plane in the current scanning mode, a maximum measurement range, a scanning period, a focal length of the beam shaping device and the mode field diameter of the connections.

[0012] Optionally, the rotational speed of the scanning device in different scanning modes fulfills the following relationship: 2zωc⋅f=4z⋅HFOWc⋅T <DFaser2 where z represents the maximum measurement range of the FMCW-LiDAR, ω represents an optical angular velocity of the scanning device, c represents the speed of light, f represents the focal length of the beam shaping device, HFOV represents the range for the field of view angle of the FMCW-LiDAR in the first plane in the current scanning mode, T represents the scanning period, and Dfiber represents the mode field diameter of the connections.

[0013] Optionally, the multiple scanning modes include at least a first scanning mode and a second scanning mode. The scanning device has a first rotational speed and a first vibration amplitude in the first scanning mode, and a second rotational speed and a second vibration amplitude in the second scanning mode. The first rotational speed is greater than the second rotational speed, and the first vibration amplitude is greater than the second vibration amplitude.

[0014] Optionally, the control device is also designed to switch the scanning mode based on one or more of a detection area, a detection result, or a detection scene.

[0015] Optionally, the control device is designed to switch the scanning mode based on one or more of the following schemes: switching to the second scanning mode when the movement speed of the FMCW LiDAR exceeds the speed threshold; switching to the first scanning mode when the movement speed of the FMCW LiDAR falls below the speed threshold; switching to the second scanning mode when the distance between an object and the FMCW LiDAR exceeds a predetermined distance threshold or when the number of point clouds obtained by detecting an object with the FMCW LiDAR is lower than a predetermined point count threshold; alternating switching between the first and second scanning modes based on a predetermined period.

[0016] Optionally, the transmit / receive device also includes a beam splitter module and an isolation module. The beam splitter module is coupled to a light source of the FMCW LiDAR and is designed to split the light signal into a local oscillator light and the detection light. The isolation module is designed to receive and output the detection light, receive the echo radiation, and separate one optical path of the echo radiation from one optical path of the detection light.

[0017] Optionally, the FMCW LiDAR also includes a detector device coupled to the transmit / receive device. The detector device is designed to receive the local oscillator light and the echo radiation and convert a light signal into an electrical signal.

[0018] Optionally, the FMCW-LiDAR also includes a data processor designed to sample the electrical signal output by the detector device, with the sampling start times differing in different sampling modes and the sampling duration remaining the same in different sampling modes.

[0019] Optionally, the sampling start time is related to the maximum measurement range of the FMCW LiDAR in a corresponding sampling mode.

[0020] Optionally, the control device is also designed to switch between different scanning modes when the scanning device is in a 0° position.

[0021] Optionally, the scanning device includes a reflective mirror and a drive module designed to drive the reflective mirror to rotate around its axis. The control device is connected to the drive module and is designed to control a current / voltage from the drive module, based on the scanning modes, to change the rotational speed and / or vibration amplitude of the reflective mirror.

[0022] Optionally, the drive module includes a resonant motor comprising a rotor and a stator, the rotor rotating about the axis between an equilibrium position and a maximum oscillation amplitude. The rotor includes a magnetic ring, the magnetic ring comprising multiple (e.g., a plurality) pairs of magnets distributed along a circumferential direction. The stator includes a coil assembly and a restoring element, the coil assembly comprising multiple (e.g., a plurality) winding coils distributed along the circumferential direction of the magnetic ring; the restoring element being designed to return the rotor to the equilibrium position about the axis.

[0023] In a second aspect, the present disclosure also provides a scanning method for an FMCW LiDAR, wherein the FMCW LiDAR comprises a transmit / receive device, a scanning device, and a control device. The transmit / receive device comprises several terminals arranged at least along the first direction, and the scanning method comprises the following steps: emitting the detection light through the terminals; collimating the detection light by a beam-shaping device; reflecting and emitting the detection light to a target space by the scanning device; and controlling the scanning device to switch between several scanning modes by the control device. The scanning device has different rotational speeds and / or oscillation amplitudes in different scanning modes. The terminals adjacent in time emit the detection light at the same predetermined time interval.

[0024] Optionally, the multiple connections can emit the detection light sequentially at the specified time interval.

[0025] Optionally, the multiple connections are divided into several groups, with the respective groups of connections emitting the detection light sequentially within the specified time interval.

[0026] Optionally, the connector is also designed to receive the echo radiation of the detection light reflected from an object. The scanning device reflects the echo radiation to the beam shaping device, while the beam shaping device focuses the echo radiation towards the connector.

[0027] Optionally, the rotational speed of the scanning device is related to a range for the field of view (FOV) of the FMCW LiDAR in the first plane in the current scanning mode, a maximum measurement range, a scanning period, a focal length of the beam shaping device and the mode field diameter of the connections.

[0028] Optionally, the rotational speed of the scanning device in different scanning modes fulfills the following relationship: 2zωc⋅f=4z⋅HFOWc⋅T <DFaser2 where z represents the maximum measurement range of the FMCW-LiDAR, ω represents an optical angular velocity of the scanning device, c represents the speed of light, f represents the focal length of the beam shaping device, HFOV represents the range for the field of view angle of the FMCW-LiDAR in the first plane in the current scanning mode, T represents the scanning period, and Dfiber represents the mode field diameter of the connections.

[0029] Optionally, the multiple scanning modes include a first scanning mode and a second scanning mode, wherein in the first scanning mode the scanning device has a first rotational speed and a first vibration amplitude, and in the second scanning mode it has a second rotational speed and a second vibration amplitude. The first rotational speed is greater than the second rotational speed, and the first vibration amplitude is greater than the second vibration amplitude.

[0030] Optionally, the step of switching the scanning device between multiple scanning modes includes switching the scanning mode based on one or more of a detection area, a detection result, or a detection scene.

[0031] Optionally, the predefined condition includes one or more of the following: switching to the second sampling mode when the movement speed of the FMCW LiDAR exceeds the speed threshold; switching to the first sampling mode when the movement speed of the FMCW LiDAR falls below the speed threshold; switching to the second sampling mode when the distance between an object and the FMCW LiDAR exceeds a predefined distance threshold or when the number of point clouds obtained by detecting an object with the FMCW LiDAR is lower than a predefined point count threshold; alternating between the first and second sampling modes based on a predefined period.

[0032] Optionally, the scanning method also includes scanning the electrical signal output by the detector, wherein the scanning start times differ in different scanning modes, the scanning duration is the same in different scanning modes, and the scanning start time is related to a maximum measurement range of the FMCW-LiDAR in a corresponding scanning mode.

[0033] Optionally, the step of controlling the scanning device to switch between the multiple scanning modes includes switching between different scanning modes when the scanning device is in a 0° position.

[0034] In a third aspect, the present disclosure provides a LiDAR. The LiDAR comprises a transceiver, a beam modifier, a scanner, and a controller. The transceiver includes a plurality of terminals arranged along a first direction. The transceiver is configured to emit a detection light based on a predetermined time sequence and to receive an echo of the detection light reflected from an object. The beam modifier is configured to collimate the detection light and focus the echo onto the transceiver. The scanner is configured to rotate about an axis to reflect the detection light from the beam modifier to a target space and to reflect the echo back to the beam modifier.The control unit is electrically connected to the probe and is designed to control the probe to switch between a variety of scanning modes, wherein the probe has different rotational speeds or oscillation amplitudes in different scanning modes, and wherein the temporally adjacent terminals are designed to emit the detection light in a predetermined time interval.

[0035] Optionally, the numerous connections are designed to emit the detection light sequentially at the specified time interval.

[0036] Optionally, the multitude of connections is divided into several groups, with one connection in each of the several groups designed to emit the detection light sequentially at the specified time interval.

[0037] Optionally, the scanner includes a first axis and is designed to rotate around the first axis to reflect the detection light at different angles in a first plane, with the first axis running parallel to the first direction and the first plane being perpendicular to the first direction.

[0038] Optionally, a vibration amplitude of the sensor corresponds to a range of field of view angles (FOV angles) of the LiDAR in the first plane.

[0039] Optionally, the rotational speed of the scanner is related to a range for the field of view (FOV) of the FMCW LiDAR in the first plane in the current scanning mode, a maximum measurement range, a scanning period, a focal length of the beam shaper and the mode field diameter of the connections.

[0040] Optionally, the speed of the scanner can be adjusted in different scanning modes: 2zωc⋅f=4z⋅HFOWc⋅T <DFaser2 where z represents the maximum measurement range of the FMCW LiDAR, ω represents an optical angular velocity of the scanner, c represents the speed of light, f represents the focal length of the beam shaper, HFOV represents the range for the field of view angle of the LiDAR in the first plane in the current scanning mode, T represents the scanning period, and Dfiber represents the mode field diameter of the connections.

[0041] Optionally, the multiple scanning modes include a first scanning mode and a second scanning mode, wherein in the first scanning mode the scanner has a first rotational speed and a first vibration amplitude, and in the second scanning mode it has a second rotational speed and a second vibration amplitude, wherein the first rotational speed is greater than the second rotational speed and the first vibration amplitude is greater than the second vibration amplitude.

[0042] Optionally, the control is also designed to switch between the multiple scanning modes based on at least one detection area, detection result, or detection scene.

[0043] Optionally, the controller is also designed to switch between multiple scanning modes based on at least one of the following schemes: switching to the second scanning mode when the LiDAR's movement speed exceeds a speed threshold; switching to the first scanning mode when the movement speed falls below the speed threshold; switching to the second scanning mode when the distance between the object and the LiDAR exceeds a predefined distance threshold; switching to the second scanning mode when the number of point clouds determined by obstacle detection with the LiDAR is lower than a predefined point count threshold; or alternating between the first and second scanning modes based on a predefined period.

[0044] Optionally, the transceiver also includes a beam splitter and an isolator. The beam splitter is coupled to a light source of the LiDAR and is designed to split a light signal into a local oscillator light and the detection light; and the isolator is designed to receive and output the detection light, receive the echo radiation, and separate one optical path of the echo radiation from one optical path of the detection light.

[0045] Optionally, the LiDAR also includes a detector coupled to the transmitter / receiver, the detector being designed to receive the local oscillator light and echo radiation and convert a light signal into an electrical signal.

[0046] Optionally, it also includes a data processor designed to sample the electrical signal output by the detector, with the sampling start times differing in different sampling modes and the sampling duration remaining the same in different sampling modes.

[0047] Optionally, the scan start time is related to the maximum measurement range of the LiDAR in a corresponding scan mode.

[0048] Optionally, the control is also designed to switch between different scanning modes when the scanner is in a 0° position.

[0049] Optionally, the scanning device includes a reflective mirror; and a driver designed to drive the reflective mirror to rotate about the axis, the controller being connected to the driver and designed to control a current or voltage of the driver based on the scanning modes to change at least one of a rotational speed or vibration amplitude of the reflective mirror.

[0050] Optionally, the driver includes a resonant motor comprising a rotor and a stator, with the rotor designed to rotate around the axis between an equilibrium position and a maximum vibration amplitude.

[0051] Optionally, the rotor includes a magnet ring comprising a plurality of magnet pairs distributed along a circumferential direction; and the stator includes a coil assembly and a restoring element, wherein the coil assembly comprises a plurality of winding coils distributed along the circumferential direction of the magnet ring, and wherein the restoring element is designed to return the rotor to the equilibrium position about the axis.

[0052] Optionally, it also includes a data processor designed to sample the electrical signal output by the detector, with the sampling start times differing in different sampling modes and the sampling duration remaining the same in different sampling modes.

[0053] In a fourth aspect, the present disclosure provides an end device comprising: a LiDAR, as described in the embodiments above, and a connecting piece designed to connect the LiDAR and the end device.

[0054] Optionally, the terminal device can include a car, a drone, or a robot.

[0055] In some embodiments, terminals of the transmit / receive device that are adjacent in time sequence send the detection light at the same predetermined time interval; and the scanning device of the FMCW-LiDAR is switched between different scanning modes by changing the rotational speed and / or the vibration amplitude of the scanning device, so that the FMCW-LiDAR can switch between different scanning modes based on different detection requirements and thus achieve different detection effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The accompanying drawings, which form part of this disclosure, serve to enhance understanding of the disclosure. The examples and their descriptions serve to illustrate this disclosure and do not constitute any impermissible limitations of this disclosure. The drawings include: Fig. Figure 1 shows a front view of an exemplary FMCW LiDAR according to some embodiments of the present disclosure. Fig. Figure 2 shows a top view of the exemplary FMCW LiDAR according to some embodiments of the present disclosure. Fig. Figure 3 shows an exemplary scanning curve of the detection beam of the exemplary FMCW LiDAR according to some embodiments of the present disclosure. Fig. Figure 4 shows an exemplary schematic diagram to illustrate the generation of a delay angle of the LiDAR according to some embodiments of the present disclosure. Fig. Figure 5A shows an exemplary first scanning mode of the scanning device according to some embodiments of the present disclosure. Fig. Figure 5B shows an exemplary second scanning mode of the scanning device according to some embodiments of the present disclosure. Fig. Figure 6 shows a diagram illustrating an exemplary structure of an FMCW LiDAR according to some embodiments of the present disclosure. Fig. Figure 7 shows an example with a sampling start time and duration in the first sampling mode and in the second sampling mode according to some embodiments of the present disclosure. Fig. Figure 8 shows an exemplary deviation between a target angle and an actual angle when switching between scanning modes according to some embodiments of the present disclosure. Fig. Figure 9 shows an exemplary deviation between the target angle and the actual angle when switching scanning modes according to some embodiments of the present disclosure. Fig. Figure 10 shows a schematic diagram illustrating an exemplary resonance motor according to some embodiments of the present disclosure. Fig. Figure 11 shows an example normalized curve of the sampling rate in a sampling mode with a large field of view (FOV). Fig. Figure 12 shows an example normalized curve of the sampling rate in a sampling mode with a small field of view (FOV). Fig. Figure 13 shows an exemplary scanning method for FMCW-LiDAR according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0057] Some exemplary embodiments are described below. The described embodiments can be modified in various ways without deviating from the meaning or scope of the present disclosure, as would be obvious to those skilled in the art. Accordingly, the drawings and descriptions are to be regarded as illustrative and not as limiting.

[0058] In the description of this disclosure, it must be understood that the orientation or position relationships represented by terms such as "central," "longitudinal," "transverse," "length," "width," "thickness," "above," "below," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," "clockwise," "counterclockwise," and the like are based on the orientation or position relationships shown in the accompanying drawings and are used only to facilitate and simplify the description of this disclosure, rather than to indicate or suggest that the devices or elements shown must be specifically oriented or designed or operated in a specific orientation. Therefore, such terms should not be interpreted as limiting the scope of this disclosure.Furthermore, terms such as "first" and "second" are used for descriptive purposes only and are not intended to indicate or suggest the relative importance or implicitly the number of technical features presented. Accordingly, the features defined as "first" and "second" may expressly or implicitly include one or more of the features. In the description of this disclosure, "multiple" means two or more, unless expressly and specifically defined otherwise.

[0059] In the description of this disclosure, it should be noted that, unless expressly stated and defined otherwise, terms such as "installation," "coupling," and "connection" are to be understood broadly, for example, as a fixed connection, detachable connection, or integral connection; or a mechanical connection, electrical connection, or intercommunication; or as a direct connection or indirect connection via an interposed medium; or internal communication between two elements or interaction between two elements. For those skilled in the art, the specific meanings of such terms herein may be interpreted in light of the specific circumstances.

[0060] Unless explicitly stated and defined otherwise, a first feature located "on" or "below" a second feature can include direct contact between the first and second features or contact via another intervening feature that does not constitute direct contact. Furthermore, if a first feature is "on," "above," or "above" a second feature, this can cover the case where the first feature is directly above or diagonally above the second feature, or simply indicate that the level of the first feature is higher than that of the second feature. If a first feature is "below," "under," or "below" a second feature, this can cover the case where the first feature is directly below or diagonally below the second feature, or simply indicate that the level of the first feature is lower than that of the second feature.

[0061] The present disclosure provides many different embodiments or examples. For the sake of simplicity, the parts and arrangements in some examples are described below. They serve only as examples and are not intended to limit the present disclosure. Furthermore, the present disclosure may repeat a reference number and / or reference letter in different examples, such repetition serving for simplification and clarity and not establishing any relationship between the various embodiments and / or arrangements described. In addition, the present disclosure provides examples of various method and material examples, but those skilled in the art may also consider applying other methods and / or using other materials.

[0062] Some embodiments of the present disclosure are described below with reference to the drawings. It should be noted that the embodiments described here serve only for the purpose of illustration and explanation and do not limit the present disclosure.

[0063] The present disclosure provides an FMCW LiDAR. The scanning mode of the FMCW LiDAR can be set. The FMCW LiDAR can comprise a transmit / receive device, a beamforming device, a scanning device, and a control device. The transmit / receive device can have multiple (e.g., a plurality of) ports arranged at least along a first direction. The transmit / receive device can emit a detection light in a predetermined time sequence. The transmit / receive device can receive an echo of the detection light reflected by an object. The beamforming device can collimate the detection light and focus the echo onto the transmit / receive device. The scanning device can rotate about at least one axis.The scanning device can reflect the detection light from the beam-shaping device to a target space and reflect the echo radiation back to the beam-shaping device. The control device can be electrically connected to the scanning device. The control device is electrically connected to the scanning device and is configured to control the scanning device to switch between several (e.g., a plurality of) scanning modes. The scanning device exhibits different rotational speeds and / or oscillation amplitudes in different scanning modes. Terminals with adjacent or consecutive transmission times in a time sequence can transmit the detection light at the same predetermined time interval. For simplicity, such terminals are referred to in this disclosure as "time-adjacent terminals."The scanning device of the FMCW LiDAR can be switched between different scanning modes by changing the rotational speed and / or the vibration amplitude of the scanning device. In the present disclosure, the complexity of controlling the light source and the transmit / receive device of the LiDAR can be reduced. Different detection effects can be achieved.

[0064] Some embodiments of the present disclosure are described in detail below.

[0065] Fig. Figure 1 shows a front view of an exemplary FMCW LiDAR according to some embodiments of the present disclosure. The paper direction is parallel to the direction of the vertical FOV of the LiDAR. Fig. Figure 2 shows a top view of the exemplary FMCW LiDAR according to some embodiments of the present disclosure. The paper direction is parallel to the direction of the horizontal FOV of the LiDAR.

[0066] Referring to Fig. 1 and Fig. 2 The FMCW LiDAR 10 comprises a transmit / receive device 11, a beamforming device 12, a scanning device 13, and a control device 14. The transmit / receive device 11 comprises several ports (e.g., port 11-1, port 11-2, ..., port 11-n, as shown in Fig. (shown in 1). The multiple connections are at least along a first direction (e.g., arrow D in Fig. 1) arranged and each can be used to detect the light L (e.g., the detection light L1, L2, ..., Ln, as shown in Fig. (1 shown) send in a predetermined time sequence. The detection light L can be emitted in the same predetermined time interval between temporally adjacent terminals.

[0067] The beam shaping device 12 can comprise a lens or a group of lenses. For example, further referring to Fig. 1. The multiple connections can be arranged at different positions on a focal plane of the beam-shaping device 12. The emitted detection light L1, L2, ..., Ln falls on the beam-shaping device; and the detection light falls on the scanning device 13 after it has been collimated by the beam-shaping device. The scanning device 13 can rotate about at least one axis. For example, further referring to Fig. 1 and Fig. 2. The scanning device 13 can rotate about the first axis (e.g. axis OO in Fig. 1 and Fig. 2) Rotate back and forth in a direction indicated by arrow R. The scanning device 13 may have a reflective surface; and the detection light L from the beam shaping device 12 may be reflected into a target space (e.g., the space around the FMCW LiDAR 10).

[0068] In some embodiments, the FMCW-LiDAR 10 may further comprise one or more other components, such as a light source, a detector, a signal processing circuit, or the like. For example, further referring to Fig. 1. The terminals 11-1 to 11-n of the transmit / receive device 11 are coupled to one or more lasers. The terminals receive the detection light emitted by the laser and emit the detection light. The detection light can fall on an object where diffuse reflection occurs. A portion of the detection light can return to the FMCW LiDAR 10 as echo radiation. The detector is designed to receive the local oscillator light and the echo radiation and convert a light signal into an electrical signal. The signal processing circuit can receive and process the electrical signal. Distance and velocity information of the object can be determined.

[0069] In some embodiments, further referring to Fig. 2. The scanning device 13 can rotate about the axis OO. If the scanning device 13 is at different angles, the detection light L1, L2, ..., Ln can be reflected in different directions in a plane perpendicular to the axis OO. Since Fig. Figure 2 shows a top view, and the projections of the detection light L1, L2, ..., Ln coincide in the drawings. The timestamps t1, t2, t3, and t4 represent four different times in time. The scanning device 13 reflects the detection light L1, L2, ..., Ln in different directions in the plane perpendicular to the axis OO to different timestamps t1, t2, t3, and t4.

[0070] Fig. Figure 3 shows an exemplary scanning curve of the detection light beam of the exemplary FMCW LiDAR, which corresponds to some embodiments of the present disclosure. The exemplary scanning curve represents a possible change in the scanning angle over time in the plane perpendicular to the axis OO of the scanning device 13. In some embodiments, the scanning device 13 can rotate in two directions about the axis OO. The scanning device 13 can rotate at a constant speed between maximum vibration amplitudes in the two directions.

[0071] In some embodiments, the multiple terminals of the FMCW-LiDAR 10 can operate in an isochronous transmission mode. For example, terminals adjacent in time can emit the detection light L at the same predetermined time interval. Furthermore, with reference to Fig. The intervals between timestamps t1 to t2, t2 to t3, and t3 to t4 are equal. The arrow pointing to timestamp t1 represents a light beam emitted after the detection light L sent to timestamp t1 has passed through the beam-shaping device 12 and the scanning device 13. The arrow at timestamp t2 represents a light beam emitted after the detection light L sent to timestamp t2 has passed through the beam-shaping device 12 and the scanning device 13, and so on. One possible scanning path of the FMCW LiDAR is shown in Fig. Figure 3 shows that in the plane perpendicular to the OO axis, the scanning angle of the LiDAR's detection light varies linearly with time between the maximum angles in the two directions (shown as ±45° in the Fig. 3) In this way, scanning with uniform angular resolution can be achieved. Additionally, terminals adjacent in time can emit the detection light at the same predefined time interval. Different terminals can be switched within the predefined time interval. This reduces the difficulty in controlling the light source and the transmitter / receiver.

[0072] In some embodiments, the scanning device 13 can operate in multiple scanning modes. The scanning device 13 can exhibit different vibration amplitudes and / or rotational speeds when operating in different scanning modes. For example, further referring to Fig. 1. The FMCW LiDAR 10 can include a control device 14. The control device can be electrically connected to the scanning device. The control device 14 can control the scanning device 13 to switch between the multiple scanning modes.

[0073] The detection light can be reflected to different angular ranges by controlling different vibration amplitudes of the scanning device, provided that the temporally adjacent terminals emit the detection light within the same predefined time interval. The LiDAR can exhibit different FOV angle ranges in different scanning modes. By controlling the different rotational speeds of the scanning device, the angular difference between two detection beams emitted in close succession can be altered. The LiDAR can exhibit different angular resolutions in different scanning modes.

[0074] In some embodiments, the frame rate of the FMCW LiDAR can be the same in different scanning modes. For example, the time required for the scanning device 13 to rotate from the maximum vibration amplitude in one direction to the maximum vibration amplitude in another direction can be the same in different scanning modes. Within the same rotation period, the greater the vibration amplitude of the scanning device, the higher its rotational speed can be.

[0075] In some embodiments, the multiple terminals can emit the detection light sequentially at a predetermined time interval. For example, only one terminal emits the detection light at any given time. By rotating the scanning device, the detection light emitted sequentially by the multiple terminals can be reflected at different angles. If the scanning device rotates at a constant speed, the LiDAR's field of view (FOV) can be scanned with uniform angular resolution.

[0076] In some embodiments, the multiple ports can be divided into several groups. The ports belonging to a group can emit light simultaneously. The respective groups of ports can sequentially emit detection light at a predetermined time interval. For example, the multiple ports in a group can emit the detection light simultaneously. The detection light can be emitted at different angles after passing through the beam-shaping device and the scanning device. Detection can be performed simultaneously at several corresponding angles. The fields of view (FOVs) corresponding to the emission angles of the detection light emitted by different groups of ports can be combined by rotating the scanning device. The detection efficiency of the LiDAR can be improved.

[0077] In some embodiments, the multiple ports can be arranged in a first direction D in a plane containing the paper plane. The first direction D is parallel to the direction of the vertical FOV of the FMCW LiDAR. The multiple ports can be arranged on a focal plane of the beam-shaping device 12 along the first direction D. After passing through the beam-shaping device 12, the detection light emitted by each port can correspond to a detection orientation of the vertical FOV of the LiDAR, as indicated by the detection light arrows L1, L2, ..., Ln in the figure. Fig. 1 shown.

[0078] The sum of the detection orientations of the n connections forms the FOV in the vertical plane (“VFOV”) of the FMCW-LiDAR 10, such as that defined by the detection light L1 and Ln in Fig. 1 defined FOV.

[0079] In some embodiments, the axis OO of the scanning device 13 runs parallel to the first direction D. By rotating the scanning device 13 about the axis OO, the vibration amplitude of the scanning device 13 corresponds to the FOV in the first plane of the FMCW LiDAR. The scanning FOV in the horizontal plane (“HFOV”) of the FMCW LiDAR 10 can be determined, e.g., the FOV indicated by the arrows corresponding to t1 and t4 in Fig. 2 is defined.

[0080] In some embodiments, further referring to Fig. 1 and Fig. 2. The VFOV of the FMCW-LiDAR 10 can be obtained by arranging the multiple connections along the first direction D (e.g., the first direction D is the vertical direction). The HFOV of the FMCW-LiDAR 10 can be determined by rotating the scanning device 13 about the axis OO. The definition of the direction in the above description is only exemplary, and the first direction D can be changed when the embodiments are implemented. For example, the first direction D can be set in the horizontal plane. The HFOV of the FMCW-LiDAR 10 can be determined by arranging the multiple connections along the first direction D (e.g., the horizontal direction as the first direction D), while the VFOV of the FMCW-LiDAR 10 can be determined (obtained) by rotating the scanning device 13 about the axis OO.

[0081] In some embodiments, the FMCW LiDAR may include other scanning devices; or the scanning device may have a second axis that is not parallel to the first direction. The detection light may be deflected in a second plane that is not parallel to the first plane. For example, the second axis of the scanning device may be perpendicular to the first direction; or the LiDAR may include a second scanning device with a second axis. The second axis may be parallel to the direction of the LiDAR's horizontal field of view (FOV). The scanning device may rotate about the second axis. The detection light may be scanned at various angles in the vertical direction. This allows the LiDAR's VFOV to be larger than the sum of the detection orientations of the n ports mentioned above.

[0082] In some embodiments, the vibration amplitude of the scanning device 13 can correspond to a range for the field of view (FOV) angle of the FMCW LiDAR in the first plane. When the scanning device 13 rotates by an angle θ, the detection light rotates by an optical angle 2θ. The range for the FMCW LiDAR's FOV angle in the first plane is twice the maximum angular difference resulting from the vibration amplitudes when the scanning device 13 rotates in two directions. The vibration amplitude of the scanning device 13 can be determined based on the FOV angle required by the FMCW LiDAR in the first plane.

[0083] In some embodiments, the axis of the scanning device 13 can be vertical, while the first plane can be a horizontal plane. The maximum vibration amplitude of the scanning device 13 can be determined from the size of the HFOV of the FMCW LiDAR in scanning mode. The difference between the maximum rotation angles of the scanning device 13 in two directions can cause the detection light to be deflected by an angle of the HFOV.

[0084] In some embodiments, the connection can be echo radiation E (e.g., echo radiation E1, ..., echo radiation En, as in Fig. (shown in Figure 1) receives the detection light L reflected from an object. For example, the FMCW LiDAR can be a LiDAR with a coaxial optical path; and the FMCW LiDAR connector can emit light and receive echo radiation.

[0085] Fig. Figure 4 shows an exemplary schematic diagram illustrating the generation of a LiDAR delay angle according to some embodiments of the present disclosure. Typically, the FOV of the LiDAR can be increased by increasing the scanning speed of the LiDAR. When the echo radiation is reflected from a distant object and falls on the LiDAR, the scanning device may already have rotated by a certain angle. For example, with reference to Fig. 4. A shift in the focus position of the echo radiation occurs after it has converged from the optical components. This shift can represent a delay angle (e.g., angle θ in ). Fig. 4) The faster the rotational speed of the scanning device, the larger the possible delay angle. This can reduce the energy of the echo radiation received by the ports. The signal-to-noise ratio and long-range detection capability can also be reduced. The long-range detection capability of FMCW LiDAR can be negatively correlated with the scanning speed. At a given scanning frequency, the measurement range can be shorter the larger the field of view (FOV).

[0086] Optionally, the rotational speed of the scanning device is related to a range for the field of view (FOV) of the FMCW LiDAR in the first plane in the current scanning mode, a maximum measurement range, a scanning period, a focal length of the beam shaping device and the mode field diameter of the connections.

[0087] In some embodiments, the connections can be designed as optical fiber connections or waveguide connections.

[0088] In some embodiments, the frame rate of the LiDAR can be constant in different scanning modes. For example, the sampling time of one period can be fixed.

[0089] Fig. Figure 5A shows an exemplary first scanning mode of the scanning device according to some embodiments of the present disclosure. Fig. Figure 5B shows an exemplary second scanning mode of the scanning device according to some embodiments of the present disclosure.

[0090] Further referring to Fig. 3. The sampling time T is set for one period, where T represents the period of the triangular wave. Within the time T, the scanning device can sample the HFOV twice in different directions. The optical angular velocity during the rotation of the scanning device can be represented as ω = 2HFOV / T. For example, with reference to Fig. 5A and Fig. 5B The delay angle θ generated by rotating the scanning device must satisfy θ = 2zω / c, where z represents a target distance and ω represents the optical angular velocity of the scanning device. If θ*f > Dfiber / 2 (e.g., f represents a focal length of the lens, and Dfiber represents a mode field diameter of the transmit / receive device terminals), the focus of the echo radiation may deviate outside the mode field of the terminal. The coupling efficiency may be reduced.

[0091] In some embodiments, the rotational speed of the scanning device satisfies the following relationship for different scanning modes: 2zωc⋅f=4z⋅HFOWc⋅T <DFaser2 z represents the maximum measurement range of the FMCW LiDAR, ω represents the optical angular velocity of the scanning device, c represents the speed of light, and f represents the focal length of the beam shaping device. HFOV represents the range for the FOV angle of the FMCW LiDAR in the first plane in the current scanning mode. T represents the scanning period, and Dfiber represents the mode field diameter of the ports. By combining the focal length f of the LiDAR's optical system and the mode field diameter Dfiber of the ports, the maximum measurement range z at a given field of view (FOV) can be determined.

[0092] In some embodiments, the multiple scanning modes can include at least a first scanning mode and a second scanning mode. In the first scanning mode, the scanning device has a first rotational speed and a first vibration amplitude. In the second scanning mode, the scanning device has a second rotational speed and a second vibration amplitude. The first rotational speed can be greater than the second rotational speed, and the first vibration amplitude can be greater than the second vibration amplitude.

[0093] Further referring to Fig. 5A and Fig. 5B The scanning device 13 oscillates about the axis OO with a first oscillation amplitude θ1 in a first scanning mode. The scanning device 13 oscillates about the axis OO with a second oscillation amplitude θ2, where θ1 is greater than θ2. In some embodiments, the scanning device 13 can perform a reciprocating scan (e.g., the scanning device moves back and forth). The scanning device 13 can oscillate about ±12θ1 and ±12θ2 The FMCW LiDAR 10 moves back and forth in two directions around the axis OO. In the first scanning mode, the HFOV of the FMCW LiDAR 10, corresponding to the first oscillation amplitude θ1, is 2θ1. The arrows indicated at timestamps t1 and t5 correspond to the directions of the reflected detection light when the scanning device 13 is in its maximum oscillation positions in both directions in the first scanning mode. In the second scanning mode, the HFOV of the FMCW LiDAR 10, corresponding to the first oscillation amplitude θ2, is 2θ2.

[0094] In some embodiments, referring to Fig. 5A and Fig. 5B allows the temporally adjacent terminals to emit the detection light within the same predetermined time interval. If the scanning device 13 has a large rotational range (e.g., the rotational range can be related to the vibration amplitude), the scanning speed can be high, and the angle between two detection light beams emitted sequentially after reflection by the scanning device 13 can be increased. The range for the total angle within which each detection light beam can be deflected can also be increased. Scanning with a large angular range and low angular resolution can be performed.In contrast, if the scanning device 13 has a small rotation range, the scanning speed can be slow, and the angle between two detection light beams emitted successively after reflection by the scanning device can be reduced. The range for the overall angle within which each detection light beam can be deflected can also be reduced. A small angular range and high angular resolution can be achieved. For example, further referring to... Fig. In the first scanning mode (5A), the first oscillation amplitude θ1 of the scanning device 13 is large, and the rotational speed is high. Detection of a large field of view (FOV) can be achieved. Additionally, the angle between the detection light beams emitted at adjacent (e.g., successive) time points after reflection by the scanning device 13 is large. Thus, the detection resolution of the scanning device 13 can be low (e.g., the distance between the arrows of the detection light in the Fig. 5A is large); and the detection mode of the scanning device 13 may be suitable for detecting objects at short distances. For example, further referring to Fig. In the second scanning mode (5B), the second rotation range θ2 of the scanning device 13 is small, while the rotational speed is large. This allows for the detection of a small field of view (FOV). Furthermore, the angle between the detection light beams emitted at adjacent times after reflection by the scanning device 13 is small. Therefore, the detection resolution can be high, and this detection mode is suitable for detecting objects at long distances.

[0095] In the present disclosure, it is easy for those skilled in the art to understand that the size of the FOV can be a relative concept. Different FOVs can be determined based on the scanning requirements of the LiDAR. For example, the HFOV can be 120° and 90° or 90° and 60°. In addition, three or more scanning modes can be specified if required. For example, the three scanning modes corresponding to FOVs of 120°, 90°, and 30° can be specified.

[0096] In some embodiments, the measuring range in the first scanning mode may be smaller than the measuring range in the second scanning mode.

[0097] In some embodiments, different scanning modes can have different vibration amplitudes and different rotational speeds, which is not limited in the present disclosure. For example, different scanning modes can have different vibration amplitudes but the same rotational speed. As another example, different scanning modes can have the same vibration amplitude but different rotational speeds. Furthermore, the predetermined time interval for emitting the detection light can be changed as needed via the multiple terminals.

[0098] The scanning device 13 can operate in various scanning modes, such as first scanning mode, second scanning mode, or the like. In some embodiments, the control device 14 can control the scanning device 13 to switch between different scanning modes based on various schemes. For example, the control device 14 can control the scanning device 13 to switch between different scanning modes based on one or more factors such as detection area, detection result, detection scene, or the like. For example, the control device 14 can switch between scanning modes based on one or more of the following schemes: The scanning device can be switched to second scanning mode when the movement speed of the FMCW LiDAR exceeds a speed threshold.The scanning device can switch to the first scanning mode when the movement speed falls below the speed threshold. The scanning device can switch to the second scanning mode when the distance between an object and the FMCW LiDAR exceeds a predefined distance threshold. The scanning device can also switch to the second scanning mode when the number of point clouds generated by object detection by the FMCW LiDAR is lower than a predefined point count threshold. The scanning device can also alternate between the first and second scanning modes based on a predefined period.

[0099] In some embodiments, if the FMCW LiDAR's speed exceeds the speed threshold (e.g., in a high-speed scenario), the scanning device can switch to the second scanning mode. This increases the LiDAR's measurement range, enabling high-resolution scanning and detection of distant objects. If the FMCW LiDAR's speed is below the speed threshold, a medium- to low-speed scenario (e.g., in an urban setting) is possible, in which case the scanning device can switch to the first scan mode. For short-range objects, low-resolution scanning and detection are possible. Typically, the LiDAR can be mounted on the vehicle. The LiDAR's speed can be determined by measuring the vehicle's speed.Furthermore, the speed of movement of the LiDAR can also be determined based on the point cloud measured by the LiDAR, which is not limited in the present disclosure.

[0100] In some embodiments, the FMCW LiDAR can perform a scan in the first scan mode and then switch to the second scan mode. For example, the FMCW LiDAR can switch to the second scan mode if it detects that the distance between the object and the FMCW LiDAR exceeds the predetermined distance threshold. As another example, the FMCW LiDAR can switch to the second scan mode if the number of point clouds generated by the object detection by the FMCW LiDAR is lower than the predetermined point count threshold. For example, the first scan mode can initially be used to scan and detect a large field of view (FOV) area outside the LiDAR. Based on the detection results, if the detected object is at a distance exceeding the predetermined distance threshold (e.g.,(An object is located at a great distance) can be switched to the second scanning mode to improve the LiDAR's resolution and perform fine far-field detection. As another example, the number of point clouds acquired during object detection by the LiDAR can be determined. If the number of point clouds is lower than the intended point threshold, the objects cannot be detected in the first scanning mode. The FMCW LiDAR can switch to the second scanning mode to detect the objects with high resolution. In the present disclosure, the number of point clouds acquired through object detection can be increased, thus improving the object detection capability.

[0101] In some embodiments, the LiDAR can alternately switch between the first and second scanning modes. In some embodiments, the LiDAR can perform one scan in the first scanning mode, then one scan in the second scanning mode, and then continue a scanning pattern of the first and second scanning modes. In some embodiments, the LiDAR can perform N scans in the first scanning mode, followed by M scans in the second scanning mode, where N > M and N and M are positive integers.

[0102] In some embodiments, the transmit / receive device may further comprise a beam splitter module and an isolation module. The beam splitter module may be coupled to a light source of the FMCW LiDAR. The beam splitter module can receive a light signal from the light source and split the light signal into local oscillator light and detection light. The isolation module can receive and output the detection light, receive the echo radiation, and separate a light path of the echo radiation from a light path of the detection light.

[0103] In some embodiments, the FMCW LiDAR may include a detector device and a transmit / receive device. The detector device may be coupled to the transmit / receive device. The detector device can receive the local oscillator light and the echo radiation. The detector device can convert the light signal into an electrical signal.

[0104] In some embodiments, the FMCW LiDAR may include a data processor. The data processor can sample the electrical signal output by a detector.

[0105] Fig. Figure 6 shows a diagram illustrating an example structure of the FMCW-LiDAR 10 according to some embodiments of the present disclosure. The FMCW-LiDAR 10 can comprise a beam-shaping device and a scanning device, which are arranged in the Fig. 6 are not shown.

[0106] Referring to Fig. Figure 6 of the FMCW LiDAR 10 comprises a light source 15 and a transmit / receive device (not marked in the drawing). The transmit / receive device includes a beam splitter module 16 and an isolation module 17. The light source 15 can emit a light signal in the form of a frequency-modulated continuous wave. The beam splitter module 16 is coupled to the light source. The beam splitter module 16 can split the light signal into local oscillator light and the detection light L, while the isolation module 17 can receive and output the detection light L. The isolation module 17 can receive the echo radiation E and separate the optical path of the echo light from the optical path of the detection light.

[0107] For example, referring further to Fig. 6, the beam splitter module 16 comprises several beam splitter units, the number of beam splitter units corresponding to the number of connections of the transmit / receive device 11, as shown in Fig. The 6 beam splitter units 161, ..., 16n shown. The isolation module 17 comprises several isolation units, the number of which can also correspond to the number of connections of the transmit / receive device 11, such as isolation unit 171, ..., isolation unit 17n, as shown in Fig. Figure 6 shows a one-to-one correspondence between the beam splitter units, the isolation units, and the terminals. The laser emitted by the light source 15 can be switched between several paths, such as path 1, ..., path n, as shown in the drawings, and the light signal in each path enters one of the beam splitter units. For example, beam splitter unit 161 receives light signal 1 and splits it into a local oscillator light V1 and a detection light L1. The detection light L1 falls on a corresponding isolation unit 171 in the isolation module 17.

[0108] In some embodiments, the isolation unit comprises a first end, a second end, and a third end. The first end is coupled to the beam splitter unit and can receive the detection light. The second end is coupled to terminals of the transmit / receive device and can output the detection light and receive the echo radiation. The third end can output the echo radiation. The isolation units of the isolation module 17 separate the optical path of the echo radiation E from the optical path of the detection light L.

[0109] In some embodiments, further referring to Fig. 6. The light signal emitted by the light source 15 is split into two parts by the beam splitter module. One small part is the local oscillator light; and the other part is the detection light, which is emitted into the surrounding area. A coaxial light path is used in the LiDAR. A detection light signal is emitted from a specific port of the transmit / receive device and reflected by the object to generate an echo signal. The echo signal is received by the same port. The echo signal is separated from the detection light signal by the isolation element.

[0110] The beam splitter unit 161, the insulating unit 171, and the connector 11-1 are described above as examples. Other beam splitter units, insulating units, and connectors are identical and are not described again here.

[0111] In some embodiments, the beam splitter unit may include a coupler. The isolation unit may include a circulator, a polarization beam splitter, or the like.

[0112] For example, referring further to Fig. 6. The FMCW LiDAR 10 can include a detector device (not marked in the drawings). The detector device comprises a frequency mixer module 18 and a photoelectric converter module 19. The frequency mixer module 18 is coupled to the beam splitter module 16 and the isolation module 17, respectively. The frequency mixer module 18 can receive the local oscillator light and the echo radiation and operate the beat frequency on the local oscillator light and the echo radiation to obtain a beat frequency signal. The photoelectric converter module 19 is coupled to the frequency mixer module 18. The photoelectric converter module 19 can receive the beat frequency signal and convert the light signal into an electrical signal.

[0113] The frequency mixer module 18, for example, comprises n frequency mixers. The frequency mixer module 18 can operate the beat frequency on the local oscillator light and the echo radiation in each path to generate a beat frequency signal. The detection module 19 comprises n photodetectors. The n photodetectors can receive the beat frequency signal in each path and perform a photoelectric conversion to obtain the electrical signal.

[0114] Further referring to Fig. 6 The FMCW-LiDAR 10 also includes a data processor 20. The data processor 20 can sample an electrical signal output by the detector.

[0115] At timestamp t1, terminal 11-1 of the transmit / receive device 11 is switched on. Terminal 11-1 can begin emitting the detection light L1 (e.g., an FMCW signal) and cease emitting the detection light L1 at timestamp t2 when it switches to another terminal (e.g., terminal 11-2). At that time, terminal 11-2 can begin emitting the detection light L2 (e.g., an FMCW signal), or something similar. Furthermore, it is readily apparent to those skilled in the art that it is not limited to emitting the detection light via only one terminal at any given time, and that multiple terminals can be controlled to simultaneously emit detection light and receive echo radiation. The position sequence of the connections for emitting the detection light is not limited to 11-1~11-n, but can be flexibly configured by experts based on the detection requirements of FMCW LiDAR.

[0116] The FMCW-LiDAR 10 can perform sampling based on the isochronous trigger mode. For example, the time interval from the trigger time for port 11-1 to the trigger time for port 11-2 can be set in different sampling modes. Due to the large amount of data that can be processed based on the distance principle of the FMCW-LiDAR 10, a lower limit t is imposed on the required data processing time for acquiring a single detection point. The parameter t is much larger than the delay time for echoes from a distance of 500 m. The interval of the switching times of the transmit / receive device ports is t. The maximum point frequency of the channels can be determined.

[0117] In some embodiments, the data processor 20 can sample an electrical signal output by the detector. The sampling start time in different sampling modes can be different, and the sampling durations in different sampling modes can be the same.

[0118] In some embodiments, the scan start time depends on the maximum measurement range of the FMCW LiDAR in the corresponding scan mode. The FMCW LiDAR can emit a continuous wave signal. Within the operating window of the transmit / receive device port, the FMCW LiDAR can emit light continuously or intermittently. When reflected by objects, a continuous echo signal is received by the LiDAR, and it takes until the reflected echo of the last transmitted light signal finally returns to the LiDAR. To reduce the data processing load, the beat frequency signal can be collected for a specific period, with the scan start time corresponding to the delay time of the echo from the furthest distance. At this point, even the echo reflected by an object at the furthest distance has already reached the LiDAR; however, the echo reflected by the object at a closer distance still exists.

[0119] Fig. Figure 7 shows an example with a sampling start time and duration in the first sampling mode and in the second sampling mode according to some embodiments of the present disclosure. Referring to Fig. Section 7 presents (a) examples of the first sampling mode with a large FOV (e.g., with a short measurement range) and (b) examples of the second sampling mode with a small FOV (e.g., with a long measurement range). In the first sampling mode, sampling is started at timestamp Δt1, and the sampling duration is δ, the length of which is determined based on the processing power, power consumption, and signal-to-noise ratio of the LiDAR. In the second sampling mode, sampling is started at timestamp Δt2, and the sampling duration is δ, where Δt1 < Δt2, and the sampling duration δ is the same in both sampling modes.

[0120] In some embodiments, the control device can control the LiDAR to switch the scanning mode based on the command to switch the scanning mode.

[0121] Fig. Figure 8 shows an exemplary deviation between a target angle and an actual angle during arbitrary switching of scanning modes according to some embodiments of the present disclosure. If the scanning mode is switched at any time, significant angular jitter can be caused in the scanning device during the switching process. For example, with reference to Fig. 8. The scanning mode of the scanning device switches during the rotation process. The actual angle may deviate from the expected value. The point cloud may jitter and cause confusion. This can reduce the detection accuracy.

[0122] In some embodiments, the control device can determine the angle of the scanning device based on the command to switch the scanning mode. For example, the control device can determine whether the scanning device is in the 0° position (e.g., the zero point position on the y-axis). Fig. 8).

[0123] In some embodiments, the control device can determine whether the scanning mode should be switched based on the angle of the scanning device. For example, if the scanning device deviates from the 0° position, the scanning mode cannot be switched. If the scanning device is in the 0° position, the scanning mode can be switched based on a scanning mode switch command. During the back-and-forth rotation of a scanning device, the direction of the driving force acting on the scanning device differs when the scanning device rotates at a positive angle compared to when the scanning device rotates at a negative angle, with the direction of the driving force reversing at the 0° position. The scanning mode can be switched in parallel with the reversal of the driving force. Jitter caused by the change in the scanning device's trajectory can be avoided or reduced. Fig. Figure 9 shows an exemplary deviation between the target angle and the actual angle when switching between scanning modes according to some embodiments of the present disclosure. The example effect is shown in Fig. Figure 9 shows the scanning FOV being switched between 30° and 90°. Using the above method, the actual angle of the scanning device essentially matches the target angle.

[0124] In some embodiments, the scanning device 13 may include a reflecting mirror and a drive module. The drive module can drive the reflecting mirror to rotate about the axis OO. The control device 14 is connected to the drive module. The control device 14 can control a current / voltage of the drive module based on the scanning mode to change the rotational speed and / or the oscillation amplitude of the reflecting device. The drive module may include a resonant motor, such as a voice coil motor. The resonant motor may include a rotor and a stator. The rotor rotates about the axis between an equilibrium position and the maximum oscillation amplitude.

[0125] For an existing voice coil motor, a mechanical model of the voice coil motor can be simplified to a second-order system of mass (m) and damping (c), and the transfer function from the driving force to the angle can be formulated as follows: A(x)F(x)=1ms2+cs where A represents an angle, F a driving force, and s an operating frequency. The damping factor is primarily determined by the frictional force of a bearing. Typically, the damping in the motor can be reduced as much as possible. With low damping, the gain of the transfer function A(x) / F(x) is inversely proportional to the square of the frequency. For example, with increasing frequency, the dynamic gain of a conventional voice coil motor can decrease rapidly. If the frequency is fixed and the scanning field of view (FOV) is to be increased, the acceleration rate in the scanning process increases with the increase in FOV. The required driving current also increases. The motor's current consumption is proportional to the square of the driving current. In the present disclosure, a high current consumption can be achieved.

[0126] To keep the power consumption within an acceptable range when switching between different sampling modes, some embodiments of the present disclosure provide a resonant motor.

[0127] Fig. Figure 10 shows a schematic diagram of a resonance motor 30 according to some embodiments of the present disclosure. For example, further referring to Fig. 10, the resonant motor 30 comprises a rotor 31 and a stator. The stator includes a coil assembly 32 and a return element 33.

[0128] The rotor 31 includes a magnetic ring. The magnetic ring contains several pairs of magnets arranged circumferentially. For example, further referring to Fig. 10, each pair of magnets comprises magnetic poles, which are indicated by different shades of gray (e.g., white and black), and different shades of gray indicate different polarities (e.g., 31-1 and 31-2 in Fig. 10) The coil assembly 32 comprises several winding coils 32-1 distributed circumferentially around the magnet ring. In some embodiments, the restoring element 33 comprises two stator magnet poles arranged radially on opposite sides of the rotor 31, the restoring element returning the rotor 31 to its equilibrium position about the axis. In particular, the axis of the rotor 31 is perpendicular to a line connecting the two stator magnet poles contained in the restoring element 33.

[0129] Fig. Figure 10 shows the rotor 31 in the equilibrium position, in which the restoring element 33 has a polarity opposite to that of the rotor 31's magnet, which is directly opposite the restoring element 33. During operation of the resonant motor 30, a current is supplied to the coil assembly 32, and the magnetic field of the rotor 31 interacts with the current in the coil assembly 32 to generate a drive torque that causes the rotor 31 to rotate from the equilibrium position in the direction of maximum oscillation amplitude. When the rotor 31 is moved from the in Fig. If the rotor 31 deviates from the equilibrium position shown in 10, it is pulled back into the equilibrium position by the attractive force generated between the magnets of the restoring element 33 and the rotor 31 with opposite polarity.

[0130] It should be noted that the expert is aware that the in Fig. Figure 10 shows that the rotor 31 is located outside the coil assembly 32. However, in some embodiments, the rotor 31 can also be arranged inside the coil assembly 32.

[0131] To minimize power consumption during scanning with a large field of view (FOV), the size of the restoring element and its distance from the rotor are adjusted so that the motor operates at its resonant frequency during FOV scanning. By introducing magnetic energy storage, generated by the magnets of the restoring element and the rotor with opposite polarities, a high gain can be achieved at the resonant frequency. Low power consumption can be achieved during FOV scanning at a specific frequency. The larger the angle between the plane in which the rotor and stator are located (e.g., the angle of the mirror) and the line connecting the two magnetic poles of the stator, the greater the restoring force acting on the rotor. The normalized curve of the restoring force is shown in Fig. 11 shown.

[0132] To improve long-range measurement capability and angular resolution, the rotational speed and oscillation amplitude of the scanning device can be reduced to decrease the field of view (FOV). At this point, the angle between the plane containing the rotor and coil assembly and the line connecting the two magnetic poles of the stator is very small. The restoring force is close to zero. Magnetic energy storage plays a negligible role, similar to the reciprocating operating mode of a conventional voice coil motor, which is accelerated and decelerated by a drive current. In this case, the current consumption can be proportional to the square of the current. However, if the oscillation amplitude is small, the rotational speed of a moving part (e.g., a mirror) can be low, and combined with the low moment of inertia, the required drive current can be small. The current consumption is also low.

[0133] When scanning with a large field of view (FOV), the moving part rotates through a larger angle, increasing the restoring force. The magnetic field between the rotor and the restoring element generates a restoring torque, providing the moving part with additional driving force. This enables high-speed scanning with a large FOV while consuming minimal power.

[0134] The normalized curve of the sampling rate is in Fig. Figure 12 illustrates this. After rotating in the positive direction for a certain period of time, it switches to rotating in the negative direction. By using the scanning device with the technical solution of the present disclosure, uniform scanning under different FOVs can be achieved.

[0135] In some embodiments, further referring to Fig. In section 10, the rotor 31 is arranged outside the coil assembly 32. The distance between the rotor 31 and the restoring element 33 can be small. The restoring force can be increased, while the power consumption can be reduced during high-speed scanning with a large field of view.

[0136] Fig. Figure 13 shows an exemplary scanning method for FMCW LiDAR according to some embodiments of the present disclosure. Referring to Fig. For example, in Section 13, the present disclosure provides a scanning method 200 for an FMCW LiDAR. The FMCW LiDAR comprises a transmit / receive device, a scan device, and a control device. The transmit / receive device includes multiple terminals arranged at least along a first direction. The FMCW LiDAR can be used in conjunction with Fig. The FMCW LiDAR described in 1-12 is used. The procedure is described below with reference to Fig. 13 described in more detail.

[0137] In step S201, a detection light is emitted from the terminals.

[0138] In step S202, the detection light is collimated by a beam shaping device.

[0139] In step S203, the detection light is reflected by the scanning device and emitted into a target space.

[0140] In step S204, the scanning device is switched between several scanning modes by the control device, whereby the scanning device has different rotational speeds and / or vibration amplitudes in different scanning modes.

[0141] In some embodiments, the temporally adjacent terminals can emit the detection light in the same predetermined time interval.

[0142] In some embodiments, the multiple terminals can emit the detection light sequentially within the specified time interval.

[0143] In some embodiments, the multiple terminals can be divided into several groups, with the respective groups of terminals emitting the detection light sequentially within the specified time interval.

[0144] In some embodiments, the terminals can further receive an echo of the detection light reflected from an object. The scanning device can reflect the echo to the beam shaping device, which can then converge the echo to the terminal.

[0145] In some embodiments, the rotational speed of the scanning device is related to a range for the FOV angle of the FMCW LiDAR in the current scanning mode, a maximum measurement range, a scanning period, a focal length of the beam shaping device, and the mode field diameter of the terminals.

[0146] In some embodiments, the rotational speed of the scanning device can satisfy the following relationship in different scanning modes: 2zωc⋅f=4z⋅HFOWc⋅T <DFaser2 z represents the maximum measurement range of the FMCW LiDAR, ω represents an optical angular velocity representing the scanning device, c represents the speed of light, f represents the focal length of the beam shaping device, HFOV represents the range for the FOV angle of the FMCW LiDAR in the first plane in the current scanning mode, T represents the scanning period, and Dfiber represents the mode field diameter of the connections.

[0147] In some embodiments, the multiple scanning modes can include at least a first scanning mode and a second scanning mode. In the first scanning mode, the scanning device has a first rotational speed and a first vibration amplitude. In the second scanning mode, it has a second rotational speed and a second vibration amplitude. The first rotational speed can be greater than the second. The first vibration amplitude can be greater than the second vibration amplitude.

[0148] In some embodiments, the step of switching the scanning device between the multiple scanning modes may include switching the scanning mode based on one or more of a detection area, a detection result, or a detection scene.

[0149] In some embodiments, the predefined condition may include one or more of the following: switching to the second sampling mode when the movement speed of the FMCW LiDAR exceeds the speed threshold; switching to the first sampling mode when the movement speed falls below the speed threshold; switching to the second sampling mode when a distance between an object and the FMCW LiDAR exceeds a predefined distance threshold or when the number of point clouds obtained by detecting an object with the FMCW LiDAR is below a predefined point count threshold; or alternating switching between the first and second sampling modes based on a predefined period.

[0150] In some embodiments, the scanning method may further include scanning the electrical signal output by the detector device. Scan start times may differ in various scanning modes. Scan durations are the same in different scanning modes. The scan start time depends on the maximum measurement range of the FMCW LiDAR in the respective scanning mode.

[0151] In some embodiments, the step of switching the scanning device between the multiple scanning modes includes: switching between different scanning modes when the scanning device is in a 0° position.

[0152] It is understood that each device, module, or unit in the embodiments of this disclosure may comprise, in whole or in part, one or more physical components. For example, a device, module, or unit may be implemented as a processor, a controller, a computer, or any type of hardware component. As another example, a device, module, or unit may comprise one or more hardware components and one or more software components. For example, the module may comprise a processor (e.g., a digital signal processor, a microcontroller, a field-programmable gate array, a central processing unit, an application-specific integrated circuit, or the like) and a computer program, wherein, when the computer program is executed on the processor, the function of the module can be realized. The computer program may be stored in a memory (e.g.,a random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory, register, hard disk, removable hard disk or storage medium of any other form) or on a server.

[0153] For example, a transmit / receive device may include a transmit / receive unit, a transmit / receive circuit, or similar. A beam shaping device may include a beam shaper, a beam shaping circuit, or similar. A scanning device may include a scanner or similar. The scanner may, for example, be a rotating mirror, an oscillating mirror, a swiveling mirror, a vibrating mirror, or similar. A control device may include a controller, a control circuit, or similar. A beam splitter module / unit may include a beam splitter, a beam splitting hardware component, or similar. An isolation module may include an isolator, a ring modulator, a polarization beam splitter, or similar. The beam splitter module and the isolation module may be implemented as the same components, such as a ring modulator, a polarization beam splitter, or similar.A frequency mixer module may include a frequency mixer, a frequency mixer circuit, a coupler, or similar components. A photoelectric converter module may include a photoelectric converter, a photoelectric converter circuit, or similar components. A data processor module may include a processor, a processor circuit, or similar components for data processing. A detector device may include a detector, a detector circuit, photodetectors, or similar components. A drive module may include a driver, a resonant motor (e.g., a voice coil motor), or similar components. The number of components in the above device, module, or unit may be one or more. For example, the detector device may include one or more detectors.

[0154] In this disclosure, the terms “a”, “an”, “one”, and “the” are to be understood as singular or plural forms, unless expressly stated otherwise in the context. For example, unless expressly stated otherwise in the context, “a transmitter / receiver” may refer to a single transmitter / receiver or to a multitude of transmitters / receivers.

[0155] The terms "or" and "and / or" in this disclosure describe a relationship of association between associated objects and represent a non-exclusive inclusion. For example, each of "A and / or B" and "A or B" can include: only "A" exists, only "B" exists, and "A" and "B" both exist, where "A" and "B" can be singular or plural. As another example, each of "A, B and / or C" and "A, B or C" can include: only "A" exists, only "B" exists, only "C" exists, "A" and "B" both exist, "A" and "C" both exist, "B" and "C" both exist, and "A," "B," and "C" all exist, where "A," "B," and "C" can be singular or plural. Additionally, the symbol " / " here indicates that the associated objects before and after the sign are in an "or" relationship. In the present revelation, the term “at least one of A or B” has an equivalent meaning to “A or B”, as described above.The term “at least one of A, B or C” has an equivalent meaning to “A, B or C”, as described above.

[0156] The term “several” in this revelation refers to a number of two or more. For example, several objects may comprise two objects or more than two objects. The term “at least one” in this revelation refers to a number of one or more. For example, at least one object may comprise one object, two objects, ten objects, or the like.

[0157] Finally, it should be noted that the above description relates only to exemplary embodiments of the present disclosure and is not intended to limit this disclosure. Although detailed descriptions have been provided for the aforementioned embodiments, those skilled in the art may still modify the technical solutions described in the aforementioned embodiments or make equivalent changes to some of the technical features. Any modifications, equivalent changes, improvements, or the like made in the spirit and principle of the present disclosure should be included within the scope of protection of the present disclosure. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] CH 202211597331.9

[0001]

Claims

[1] FMCW LiDAR, including: a transmitting / receiving device with a plurality of terminals arranged at least along a first direction and designed to emit a detection light at predetermined time sequences and to receive an echo of the detection light reflected by an obstacle; a beam shaping device designed to collimate the detection light and converge the echo radiation onto the transmit / receive device; a scanning device designed to rotate about at least one axis in order to reflect the detection light from the beam shaping device into a target space and to reflect the echo radiation back to the beam shaping device; and a control device which is electrically connected to the scanning device and is designed to control the scanning device to switch between several scanning modes, wherein the scanning device has different rotational speeds and / or vibration amplitudes in different scanning modes; the temporally adjacent connections are designed to emit the detection light within a specified time interval. [2] FMCW LiDAR according to claim 1, wherein the plurality of connections is designed to emit the detection light sequentially in the specified time interval. [3] FMCW-LiDAR according to claim 1, wherein the plurality of connections is divided into a plurality of groups and the respective groups of connections emit the detection light sequentially in the specified time interval. [4] FMCW-LiDAR according to claim 2 or 3, wherein the scanning device has a first axis and the scanner rotates about the first axis to reflect the detection light at different angles in a first plane, wherein the first axis is parallel to the first direction and the first plane is perpendicular to the first direction. [5] FMCW LiDAR according to claim 4, wherein the vibration amplitude of the sensor corresponds to a range for the field of view angle (FOV angle) of the FMCW LiDAR in the first plane. [6] FMCW-LiDAR according to claim 4, wherein the rotational speed of the scanning device is related to a range for the field of view angle (FOV angle) of the FMCW-LiDAR in the first plane in the current scanning mode, a maximum measurement range, a scanning period, a focal length of the beam shaping device and the mode field diameter of the connections. [7] FMCW LiDAR according to claim 6, wherein the rotational speed of the scanning device in different scanning modes satisfies the following relationship: 2zωc⋅f=4z⋅HFOWc⋅T <DFaser2 where z represents the maximum measurement range of the FMCW-LiDAR, ω represents an optical angular velocity of the scanning device, c represents the speed of light, f represents the focal length of the beam shaping device, HFOV represents the range for the field of view angle of the FMCW-LiDAR in the first plane in the current scanning mode, T represents the scanning period, and Dfiber represents the mode field diameter of the connections. [8] FMCW-LiDAR according to one of claims 1 to 3, wherein the multiple scanning modes comprise a first scanning mode and a second scanning mode, the scanning device in the first scanning mode has a first rotational speed and a first vibration amplitude, and the scanning device in the second scanning mode has a second rotational speed and a second vibration amplitude, wherein the first rotational speed is greater than the second rotational speed and the first vibration amplitude is greater than the second vibration amplitude. [9] FMCW LiDAR according to claim 8, wherein the controller is further configured to switch the scanning mode based on one or more of a detection area, a detection result or a detection scene. [10] FMCW LiDAR according to claim 9, wherein the controller is designed to switch the sampling mode based on one or more of the following schemes: Switch to the second sampling mode when the movement speed of the FMCW LiDAR exceeds a speed threshold; switch to the first sampling mode when the movement speed falls below the speed threshold; Switch to the second scanning mode when the distance between an obstacle and the FMCW LiDAR exceeds a predetermined distance threshold, or when the number of point clouds determined by the FMCW LiDAR's detection of an obstacle is less than a predetermined point count threshold; Alternating switching between the first sampling mode and the second sampling mode based on a predetermined period. [11] FMCW LiDAR according to any one of claims 1 to 3, wherein the transmitter / receiver further comprises a beam splitter module and an isolation module, wherein the beam splitter module is coupled to a light source of the FMCW LiDAR and is designed to split a light signal into a local oscillator light and the detection light; and wherein the isolation module is designed to receive or output the detection light and to receive the echo radiation and to separate a light path of the echo radiation from a light path of the detection light. [12] FMCW-LiDAR according to one of claims 1 to 3, further comprising a detector device coupled to the transmitter / receiver, wherein the detector device is designed to receive the local oscillator light and the echo radiation and to convert a light signal into an electrical signal. [13] FMCW-LiDAR according to claim 12, further comprising a data processor designed to sample the electrical signal output by the detector device, wherein sampling start times are different in different sampling modes and the duration of sampling is the same in different sampling modes. [14] FMCW-LiDAR according to claim 13, wherein the sampling start time is related to a maximum measurement range of the FMCW-LiDAR in a corresponding sampling mode. [15] FMCW LiDAR according to any one of claims 1 to 3, wherein the control is further configured to switch between different scanning modes when the scanning device is in a 0° position. [16] FMCW LiDAR according to any one of claims 1 to 3, wherein the scanning device comprises: a reflective mirror; and a drive module designed to drive the reflecting mirror to rotate around the axis; wherein the control device is connected to the drive module and is designed to control a current / voltage of the drive module based on the scanning modes, and to change a rotational speed and / or vibration amplitude of the reflection mirror. [17] FMCW-LiDAR according to claim 16, wherein the drive module comprises a resonant motor, the resonant motor comprising a rotor and a stator and the rotor being designed to rotate about the axis between an equilibrium position and a maximum vibration amplitude, wherein the rotor comprises a magnetic ring, wherein the magnetic ring comprises a plurality of magnet pairs distributed along a circumferential direction; and wherein the stator comprises a coil assembly and a restoring element, wherein the coil assembly comprises a plurality of winding coils distributed along the circumferential direction of the magnet ring, and wherein the restoring element is designed to return the rotor to the equilibrium position about the axis. [18] Scanning method for an FMCW LiDAR, wherein the FMCW LiDAR comprises a transmitter / receiver, a scanning device and a controller, wherein the transmitter / receiver has multiple terminals arranged at least along the first direction, wherein the scanning method comprises: Emitting the detection light through the terminals; Collimating the detection light using a beam shaping device; Reflecting and emitting the detection light into a target space by the scanning device; Control of the scanning device for switching between a multitude of scanning modes by the control device, wherein the scanning device has different rotational speeds and / or vibration amplitudes in different scanning modes, where the temporally adjacent connections emit the detection light in the same predetermined time interval. [19] Scanning method according to claim 18, wherein the plurality of connections sends the detection light sequentially in the specified time interval. [20] Scanning method according to claim 18, wherein the plurality of connections is divided into a plurality of groups and the respective groups of connections emit the detection light sequentially in the specified time interval. [21] Scanning method according to claim 18, wherein the connection is further configured to receive echo radiation of the detection light reflected by an obstacle, wherein the scanning device reflects the echo radiation to the beam shaping device and the beam shaping device converges the echo radiation to the connection. [22] Scanning method according to claim 21, wherein the rotational speed of the scanning device is related to a range for the field of view angle (FOV angle) of the FMCW LiDAR in the current scanning mode, a maximum measurement range, a scanning period, a focal length of the beam shaping device and the mode field diameter of the connections. [23] Sampling method according to any one of claims 18 to 22, wherein the rotational speed of the scanning device in different scanning modes satisfies the following relationship: 2zωc⋅f=4z⋅HFOWc⋅T <DFaser2 where z represents the maximum measurement range of the FMCW-LiDAR, ω represents an optical angular velocity of the scanning device, c represents the speed of light, f represents the focal length of the beam shaping device, HFOV represents the range for the field of view angle of the FMCW-LiDAR in the first plane in the current scanning mode, T represents the scanning period, and Dfiber represents the mode field diameter of the connections. [24] Sampling method according to one of claims 18 to 22, wherein the plurality of sampling modes comprises a first sampling mode and a second sampling mode, the sampling device in the first sampling mode has a first rotational speed and a first vibration amplitude and the sampling device in the second sampling mode has a second rotational speed and a second vibration amplitude, wherein the first rotational speed is greater than the second rotational speed and the first vibration amplitude is greater than the second vibration amplitude. [25] Sampling method according to claim 24, wherein the step of switching the scanning device between a plurality of scanning modes comprises switching the scanning mode based on one or more of a detection area, a detection result or a detection scene. [26] Sampling method according to claim 25, wherein the specified condition comprises one or more of the following: Switch to the second sampling mode when the movement speed of the FMCW LiDAR exceeds a speed threshold; switch to the first sampling mode when the movement speed falls below the speed threshold; Switch to the second scanning mode when the distance between an obstacle and the FMCW LiDAR exceeds a predetermined distance threshold, or when the number of point clouds determined by the FMCW LiDAR's detection of an obstacle is less than a predetermined point count threshold; Alternating switching between the first sampling mode and the second sampling mode based on a predetermined period. [27] Sampling method according to one of claims 18 to 22, further comprising sampling the electrical signal output by the detector device, wherein the sampling start times are different in different sampling modes, the duration of the sampling is the same in different sampling modes and the sampling start time is related to a maximum measurement range of the FMCW-LiDAR in a corresponding sampling mode. [28] Sampling method according to any one of claims 18 to 22, wherein the step of controlling the scanning device to switch between the plurality of scanning modes includes switching between different scanning modes when the scanning device is in a 0° position.

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