CN220305497U - Scanner of LiDAR system - Google Patents

Abstract

A scanner of a LiDAR system comprising: a mirror configured to redirect the optical signal emitted by the optical emitter; a first axis scanning system configured to rotate the mirror about a first axis and relative to the optical emitter, which controls a first emission angle of the light signal from the LiDAR system into a field of view of the LiDAR system; and a second axis scanning system configured to rotate the mirror about the second axis and relative to the optical emitter, which controls a second emission angle of the light signal from the LiDAR system into the field of view. The first axis scanning system is configured to rotate the reflective surface of the mirror at least 22.5 degrees in a positive rotational direction and in a negative rotational direction relative to a center position of the mirror.

Description

Scanner of LiDAR system

Technical Field

The present disclosure relates generally to light detection and ranging (light detection and ranging, "LiDAR") technology, and more particularly, to scanners of LiDAR systems.

Background

Light detection and ranging ("LiDAR") systems measure properties of their surroundings (e.g., shape of a target, profile of a target, distance to a target, etc.) by illuminating a target with pulsed laser light and measuring reflected pulses with a sensor. The difference in laser return time and wavelength can then be used to digitally, three-dimensional ("3D") represent the surrounding environment. LiDAR technology may be used in a variety of applications, including autonomous vehicles, advanced driver assistance systems, mapping, security, surveying, robotics, geology and soil science, agriculture, unmanned aerial vehicles, on-board obstacle detection (e.g., obstacle detection systems for aircraft), and the like. Depending on the application and the associated field of view (FOV), multiple channels or laser beams may be used to produce an image of the desired resolution. LiDAR systems with a greater number of channels can generally generate a greater number of pixels.

In conventional multi-channel LiDAR devices, an optical transmitter is paired with an optical receiver to form multiple "channels". In operation, the transmitters of the individual channels emit optical (e.g., laser) illumination signals into the environment of the device, and the receivers of the individual channels detect the portion of the return signal reflected back to the receivers by the surrounding environment. In this way, each channel provides a "point" measurement of the environment, which may be aggregated with the point measurements provided by the other channel(s) to form a "point cloud" of measurements of the environment.

Advantageously, the measurements collected by any LiDAR channel can be used, among other things, to determine the distance (i.e., the "range") from the device to a surface in the environment that reflects the transmitted optical signal of the channel back to the receiver of the channel. The distance to the surface may be determined based on a time of flight (TOF) of the channel signal (e.g., the time elapsed from the transmission of an optical (e.g., illumination) signal by the transmitter to the receipt of a return signal reflected by the surface by the receiver).

In some examples, liDAR measurements may also be used to determine the reflectivity of a surface that reflects an optical (e.g., illumination) signal. The reflectivity of a surface may be determined based on the strength of the return signal, which generally depends not only on the reflectivity of the surface, but also on the distance to the surface, the glancing angle of the transmitted signal relative to the surface, the power level of the transmitter of the channel, the alignment of the transmitter and receiver of the channel, and other factors.

Disclosure of Invention

In view of the technical problem of how to provide a more efficient LiDAR system, a scanner of a LiDAR system is provided, comprising: a mirror having a reflective surface configured to redirect the optical signal emitted by the optical emitter; a first axis scanning system configured to rotate the reflective surface of the mirror about a first axis and relative to the optical emitter, the first axis scanning system controlling a first emission angle of the light signal from the LiDAR system into a field of view of the LiDAR system; and a second axis scanning system configured to rotate the reflective surface of the mirror about the second axis and relative to the optical emitter, the second axis scanning system controlling a second emission angle of the light signal from the LiDAR system into a field of view of the LiDAR system. The first axis scanning system is configured to rotate the reflective surface of the mirror at least 22.5 degrees in a positive rotational direction and 22.5 degrees in a negative rotational direction relative to a center position of the reflective surface of the mirror.

The scanner of the LiDAR system according to the above-described solution eliminates the need for a typical rotary motor, thus reducing the need for bearings or other friction-causing mechanisms. This allows for reduced cost, wear and energy required to drive the LIDAR system.

Drawings

The accompanying drawings, which are included as part of the present specification, illustrate the presently preferred embodiments and together with the general description given above and the detailed description of the preferred embodiments given below serve to explain and teach the principles described herein.

FIG. 1 shows a diagram of a LiDAR system according to some embodiments.

FIG. 2A shows a diagram illustrating the operation of a LiDAR system according to some embodiments.

FIG. 2B shows a diagram of the optical components of a channel of a LiDAR system according to some embodiments.

Fig. 3A illustrates a side view of a first axis of an exemplary scanning mirror system, according to some embodiments. Fig. 3B illustrates an isometric view of a first axis of the exemplary scanning mirror system of fig. 3A.

Fig. 4A illustrates an isometric view of a second axis of an exemplary scanning mirror system, according to some embodiments. Fig. 4B illustrates a side view of a second axis of the exemplary scanning mirror system of fig. 4A.

Fig. 5 illustrates another embodiment of a scanning mirror system.

Fig. 6A, 6B, and 6C illustrate various views of an exemplary fast axis of a scanning mirror system according to some embodiments.

Fig. 6D illustrates another embodiment of a first axis of an exemplary scanning mirror system.

FIG. 7 illustrates operation of an exemplary scanning mirror in accordance with some embodiments.

Fig. 8 illustrates a side view of a scanning mirror system having the first axis of fig. 3A-3B and the second axis of fig. 4A-4B.

Fig. 9 illustrates a side view of the scanning mirror system of fig. 5.

Fig. 10 illustrates a perspective view of another embodiment of a scanning mirror system.

FIG. 11 illustrates a cross-sectional view of another embodiment of a second axis of an exemplary scanning mirror system.

FIG. 12 illustrates a perspective view of the scanning mirror system of FIG. 11, according to some embodiments.

FIG. 13 illustrates a side view of the scanning mirror system of FIG. 11, according to some embodiments.

Fig. 14 illustrates another perspective view of the scanning mirror system of fig. 11, in accordance with some embodiments.

Fig. 15 provides an example of raster scanning to illustrate movement of the scanning mirror mechanism.

Fig. 16A is a graph of angle of an exemplary trace (as described above) as a function of time. Fig. 16B is a graph of the angle of an exemplary laser trace of an experimental setup of a scanning mirror system.

Fig. 17A-17B illustrate two views of an exemplary scanning pattern of an exemplary scanning mirror.

FIG. 18 illustrates a block diagram of a computing device/information handling system in accordance with some embodiments.

While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. The disclosure is not to be construed as limited to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure.

Detailed Description

Various exemplary embodiments of scanners, 3D point cloud measurement systems, and methods of a LiDAR system are disclosed herein. An exemplary measurement system may include a scanning mirror system (e.g., rather than a rotating assembly). The scanning mirror(s) may have a first axis and a second axis. As used herein, a first axis may be referred to as a "fast" axis and a second axis may be referred to as a "slow" axis. The scanning mirror mechanism may be controlled to emit and detect photons to produce a 3D point cloud.

Terminology

Measurement results, dimensions, amounts, etc. may be presented herein in a range format. The description of the range format is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the utility model. Accordingly, the description of a range should be considered to specifically disclose all possible sub-ranges and individual values within the range. For example, a description of a range such as 10 to 20 meters should be considered to have specifically disclosed sub-ranges such as 10 to 11 meters, 10 to 12 meters, 10 to 13 meters, 10 to 14 meters, 11 to 12 meters, 11 to 13 meters, etc.

Furthermore, connections between components or systems in the figures are not intended to be limited to direct connections. Rather, data or signals between these components may be modified, reformatted, or otherwise changed by intermediate components. Furthermore, additional or fewer connections may be used. The terms "coupled," "connected," or "communicatively coupled" should be understood to include a direct connection, an indirect connection through one or more intermediary devices, a wireless connection, and the like.

Reference in the specification to "one embodiment," "a preferred embodiment," "an embodiment," "some embodiments," or "embodiments" means that a particular feature, structure, characteristic, or function described in connection with the embodiments is included in at least one embodiment of the utility model, and may be in more than one embodiment. Furthermore, the appearances of the above-identified phrases in various places in the specification are not necessarily all referring to the same embodiment or embodiments.

Certain terminology is used in various locations throughout the specification for purposes of illustration only and is not to be construed as limiting. The service, function or resource is not limited to a single service, function or resource; the use of these terms may refer to a set of related services, functions, or resources that may be distributed or aggregated.

Furthermore, one skilled in the art will recognize that: (1) certain steps may optionally be performed; (2) steps may not be limited to the particular order set forth herein; (3) certain steps may be performed in a different order; and (4) certain steps may be performed simultaneously or concurrently.

The term "about", the phrase "about equal to" and other similar phrases (e.g., "X has a value of about Y" or "X is about equal to Y") as used in the specification and claims should be understood to mean that one value (X) is within a predetermined range of another value (Y). The predetermined range may be plus or minus 20%, 10%, 5%, 3%, 1%, 0.1% or less than 0.1% unless otherwise indicated.

The indefinite articles "a" and "an" as used in the specification and claims should be understood to mean "at least one" unless explicitly indicated to the contrary. The phrase "and/or" as used in the specification and claims should be understood to mean "either or both" of the elements so combined, i.e., elements that in some cases exist in combination and in other cases exist separately. The listing of "and/or" elements should be construed in the same manner, i.e., "one or more of the elements so combined. In addition to the elements specifically identified in the "and/or" clause, other elements may optionally be present, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to "a and/or B" when used in conjunction with an open language such as "comprising" may refer in one embodiment to a alone (optionally including elements other than B); in another embodiment, only B (optionally including elements other than a); in yet another embodiment, both a and B are referred to (optionally including other elements).

As used in the specification and claims, "or" should be understood to have the same meaning as "and/or" as defined above. For example, when items are separated in a list, "or" and/or "should be construed as inclusive, i.e., including at least one of a plurality or a series of elements, but also including more than one, and optionally, additional unlisted items. Only terms explicitly indicated to the contrary, such as "only one" or "exactly one", or when used in a claim, "consisting of" will mean comprising exactly one element of a plurality or list of elements. In general, when an exclusive term precedes the term "or," such as "either," "one of," "only one of," or "exactly one of," the term "or" is used only to be interpreted as indicating an exclusive substitution (i.e., "one or the other, but not both"). As used in the claims, "consisting essentially of.

As used in the specification and claims, the phrase "at least one" with respect to a list of one or more elements is to be understood as meaning at least one element selected from any one or more elements of the list, but not necessarily including at least one of the individual elements specifically listed in the list, and not excluding any combination of elements in the list. This definition also allows that elements may optionally be present other than those specifically identified in the list of elements to which the phrase "at least one" refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, "at least one of a and B" (or equivalently, "at least one of a or B," or equivalently, "at least one of a and/or B") may refer, in one embodiment, to at least one, optionally including more than one, a, without the presence of B (and optionally including elements other than B); in another embodiment, at least one, optionally including more than one B, without a being present (and optionally including elements other than a); in yet another embodiment, it means at least one a, optionally including more than one a, and at least one B, optionally including more than one B (and optionally including other elements).

The use of "including," "comprising," "having," "containing," "involving," and variations thereof herein, is meant to encompass the items listed thereafter and additional items.

Use of ordinal terms such as "first," "second," "third," etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed. Ordinal terms are used merely as labels to distinguish one claim element having a particular name from another element having the same name (but for use of the ordinal term) to distinguish the claim elements.

Some examples of LiDAR systems

Light detection and ranging ("LiDAR") systems may be used to measure the shape and profile of the environment surrounding the system. LiDAR systems may be applied to many applications including autonomous navigation and mapping of surfaces in the air. Typically, liDAR systems emit pulses of light (e.g., illumination) such as laser pulses, which are then reflected by objects within the environment in which the system operates. The time (i.e., time of flight) from when each pulse is transmitted to when it is received can be measured to determine the distance between the LiDAR system and the object that reflected the pulse. The science of LiDAR systems is based on the physical properties of light and optics.

In LiDAR systems, light may be emitted from a fast emitting laser. The laser light passes through the medium and reflects from surface points in the environment (e.g., surfaces of buildings, branches, vehicles, etc.). The reflected light energy returns to the LiDAR detector where it can be recorded and used to map the environment.

FIG. 1 depicts the operation of the mid-range and long-range portions of an exemplary LiDAR system 100 according to some embodiments. In the example of FIG. 1, liDAR system 100 includes LiDAR device 102, which may include a transmitter 104 configured to generate and transmit an emitted light signal 110, a receiver 106 configured to detect a return light signal 114, and a control and data acquisition module 108. The transmitter 104 may include a light source (e.g., a laser), electrical components operable to activate ("drive") and deactivate the light source in response to an electrical control signal, and optical components adapted to shape and redirect light emitted by the light source. The receiver 106 may include an optical detector (e.g., a photodiode) and optical components adapted to shape the return light signals 114 and direct these signals to the detector. In some implementations, one or more optical components (e.g., lenses, mirrors, etc.) may be shared by the transmitter and the receiver. LiDAR device 102 may be referred to as a LiDAR transceiver or "channel. In operation, a transmitted optical signal 110 propagates through the medium and is reflected from object(s) 112, whereby a return optical signal 114 propagates through the medium and is received by receiver 106.

The control and data acquisition module 108 may be adapted to control the optical emission of the transmitter 104 and may record data derived from the return optical signal 114 detected by the receiver 106. In some embodiments, the control and data acquisition module 108 is further adapted to control the power level at which the transmitter 104 operates when emitting light. For example, the transmitter 104 may be configured to operate at a plurality of different power levels, and the control and data acquisition module 108 may select the power level at which the transmitter 104 operates at any given time. Any suitable technique may be used to control the power level at which the transmitter 104 operates. In some variations, the control and data acquisition module 108 may be adapted to determine (e.g., measure) a particular characteristic of the return optical signal 114 detected by the receiver 106. For example, the control and data acquisition module 108 may be configured to measure the intensity of the return light signal 114 using any suitable technique.

LiDAR device 102 may include one or more optical lenses and/or mirrors (not shown) to send and shape emitted light signals 110 and/or redirect and shape return light signals 114. For example, the transmitter 104 may emit a laser beam having a particular sequence of pulses. The design elements of the receiver 106 may include its horizontal field of view (hereinafter, "FOV") and its vertical FOV. Those skilled in the art will recognize that the FOV parameters effectively define the viewable area associated with a particular LiDAR device 102. More generally, the horizontal FOV and vertical FOV of the LiDAR system 100 may be defined by a single LiDAR device (e.g., sensor), or may be associated with multiple configurable sensors (which may be exclusive LiDAR sensors, or may have different types of sensors). The FOV may be considered a scanning area for LiDAR system 100. A scanning mirror may be used to obtain the scan FOV.

In some implementations, the LiDAR system 100 may also include or may be electronically coupled to a data analysis and interpretation module 109, which may be adapted to receive output from the control and data acquisition module 108 (e.g., via connection 116), and further perform data analysis functions on, for example, return signal data. Connection 116 may be implemented using wireless or contactless communication technology.

FIG. 2A illustrates the operation of the mid-range and long-range portion(s) of LiDAR system 202 according to some embodiments. In the example of fig. 2A, two return optical signals 203 and 205 are shown, corresponding to a mid-range return signal and a long-range return signal. The laser beams generally tend to diverge as they pass through the medium. Due to the beam divergence of the laser light, a single laser emission may hit multiple objects located at different distances from the LiDAR system 202, thereby producing multiple return signals 203, 205. The LiDAR system 202 may analyze the plurality of return signals 203, 205 and report one of the return signals 203, 205 (e.g., the strongest return signal, the last return signal, etc.) or more than one (e.g., all) of the return signals 203, 205. In the illustrative example shown in FIG. 2A, the LiDAR system 202 emits a laser beam in the direction of the mid-range wall 204 and the long-range wall 208. As shown, a majority of the emitted beam hits the middle-range wall 204 at region 206, thereby generating (e.g., middle-range) return signal 203, while another portion of the emitted beam hits the long-range wall 208 at region 210, thereby generating (e.g., long-range) return signal 205. Return signal 203 may have a shorter TOF and stronger received signal strength than return signal 205. In both single-return and multi-return LiDAR systems 202, it is important that each return signal 203, 205 be accurately associated with the transmitted (e.g., illuminated) light signal so that accurate TOF can be calculated.

Some embodiments of LiDAR systems may capture distance data in a (e.g., single-plane) two-dimensional (2D) point cloud. These LiDAR systems may be used for industrial applications, or for surveying, mapping, autonomous navigation, and other uses. Some embodiments of these systems rely on the use of a single laser emitter/detector pair in combination with a moving mirror to effect scanning across at least one plane. The mirror may reflect emitted light from a transmitter (e.g., a laser diode) and/or may reflect return light to a detector. The use of movable mirrors in this manner may enable LiDAR systems to achieve 60-360 degree azimuthal (horizontal) field of view while simplifying both system design and manufacturability. In some embodiments, the movable mirror may be a vibrating mirror that scans in at least one direction (e.g., horizontal or vertical) by vibrating on an axis. The vibrations may provide the LiDAR system with a 10-180 degree (e.g., 60 to 120 degrees, 70 degrees, 90 degrees, or 120 degrees) field of view in the direction of the vibration scan via the mirror. Many applications require more data than just a single (e.g., 2D) plane. However, the 2D point cloud may be extended to form a 3D point cloud, where multiple 2D point clouds are used, each pointing at a different elevation (i.e., vertical) angle. Design elements of the receiver of the LiDAR system 202 may include a horizontal FOV and a vertical FOV.

FIG. 2B depicts a set of optical components 250 of LiDAR device 102 of LiDAR system 100 according to some embodiments. In the example of FIG. 2B, liDAR device 102 uses a single emitter 252/detector 262 pair in combination with a fixed mirror 254 and a movable mirror 256 to effectively scan across a plane. The distance measurements obtained by such a system may effectively be two-dimensional (e.g., planar), and the captured distance points may be rendered as a 2D (e.g., monoplane) point cloud. In some embodiments, but not by way of limitation, the movable mirror 256 may vibrate at a very fast speed (e.g., thousands of cycles per minute).

The emitted laser light signal 251 may be directed to a fixed mirror 254, which may reflect the emitted laser light signal 251 to a movable mirror 256. When the movable mirror 256 moves (e.g., vibrates), the emitted laser signal 251 may reflect off of the object 258 in its propagation path. The reflected return signal 253 can be coupled to a detector 262 via a movable mirror 256 and a fixed mirror 254. Design elements of LiDAR system 202 include a horizontal FOV and a vertical FOV, which define a scanning area.

Some implementations of scanning mirror mechanisms for LiDAR systems Embodiments of the invention

The scanning mirror is used to control where photons are transmitted and detected in order to create a 3D point cloud. This eliminates the need for a typical rotary motor, thus reducing the need for bearings or other friction-inducing mechanisms. This allows for reduced cost, wear and energy required to drive the LIDAR system.

The mirror is electromagnetically rotationally vibrated to control rotation of the mirror in one or more axes. The scanning mirror mechanism includes mirrors, magnets, coils, structures, position/rotation sensors, and flexures (flexures). The flexure may be made of thin metal or parallel wire strands (e.g., non-twisted parallel wires) that are structurally fixed at both ends and allow for twisting with the mirror and mirror mechanism.

Fig. 3A-3B illustrate a first (or fast) axis 300 of an exemplary scanning mirror system. The fast axis 300 may include a scanning mirror 302, a flexure 304, a magnet 306, one or two coils 308, and a sensor 310. The coil 308 may be a copper wound coil.

Fig. 3B illustrates the winding direction of the coil 308. Sensor 310 may be a hall effect sensor. The fast (or first) axis may be configured to operate at the resonant frequency of the mechanism (including flexure 304, mirror 302, and magnet 306). In various implementations, the resonant frequency of the mechanism may be a frequency in the range of 40-1000 Hz. The flexure 304 is secured (e.g., mounted, glued, etc.) to the mirror 302, and the magnet 306 is secured (e.g., mounted, glued, etc.) to the flexure 304.

The flexure 304 may be a sheet of metal (e.g., spring steel) or a bundle of metal wires (e.g., parallel or twisted wires) designed to twist at a particular frequency depending on the mass of the mirror 302 and magnet 306 and the tension of the flexure 304. In some implementations, the curved member 304 can have a thickness of about 0.004 inches, or in the case of parallel wire bundles, a diameter of about 0.008 inches. There are various ways to tension the flexure(s) 304, including, for example, a small shaft in a cylinder with an off-axis shaft that rotates to create tension; a lever mechanism including tightening a screw against a surface to create tension and/or resiliently flexing a flexure holder to mount a spring and return the spring to a tensioning mechanism. The fast axis flexure 304 of a scanning mirror system with a wire harness may provide greater reliability (relative to sheet metal) by resisting breakage as the mirror 302 rotates through multiple cycles. The flexure 304 may provide improved robustness, particularly when the system is subjected to lateral impact, providing improved impact resistance. In some embodiments, bushings are used to secure the coupling between the flexure 304 and other components of the scanning mirror system.

The first shaft 300 may be controlled by two coils 308 in series facing each other. This allows the magnet 306, which is connected to the flexure 304, to move as a pendulum, thus rotationally vibrating the mirror 302, and by facing each other, the coil 308 equalizes the magnetic field between the coils, which allows the hall effect sensor 310 to detect only the position of the magnet 306, not the magnetic field of the coil. The hall effect sensor(s) 310 and the magnet(s) 306 may be used to determine the rotational position of the mirror 302. Other sensors, such as photodiodes, may also be used in various implementations.

Fig. 4A illustrates a second (or slow) axis 400 of an exemplary scanning mirror system. The slow axis may include a tensioning mechanism 402 (e.g., an off-axis cam mechanism), a flexure 404, and a support 406. The bends 404 may be made of spring steel or parallel wire bundles. In some implementations, the curved member 404 can have a thickness of about 0.004 inches or about 0.008 inches. The mirror 302 may be disposed in a support 406.

Fig. 4B illustrates a slow axis 400 of an exemplary scanning mirror system without the mirror 302 to illustrate components behind the mirror 302. The system may include one or more magnets 408 and one or more coils 410 on a second (or slow) shaft 400. The system may also include one or more hall effect sensors 412 for the second (or slow) shaft 400.

The second (or slow) axis 400 may not be controlled at the resonant frequency of the component. The second (or slow) axis 400 may be driven in a determined order to create a scan pattern (refer to the example scan patterns of fig. 17A-17B). Slow axis 400 may be 90 ° relative to fast axis 300 and may include component(s) of fast axis 300. The slow axis 400 may be controlled to synchronize with the fast axis 300. The slow axis 400 may be driven at a frequency in the range of 1-30 Hz. For the second (or slow) axis 400, various exemplary implementations exist.

In a first implementation, the moving parts of the slow axis 400 (which have a greater design and lower rotational travel capability) may include the structure (support 406), magnets 408 on each side of the support 406, parts of the fast axis (e.g., mirror 302, flexure 304, and magnet 306), and flexures 404 (which may also be ropes or shafts) connected to each side of the support 406 on their axes of rotation. Near each standoff magnet 408 there is a fixed copper wound coil 410 (2 total). These coils 410 may be driven in series to rotationally vibrate the support 406 and its components.

In another implementation, the moving parts of the slow axis 400 (which have a smaller design and a larger rotational travel) include a structure (support 406), moving parts of the fast axis (e.g., mirror 302, flexure 304, and magnet 306), flexures 404 connected to each side of support 406 on the rotational axis of support 406 (these flexures may also be ropes or shafts), and copper wound coils on one side of the support. Around the copper wound coil there is a fixed magnet, which allows it to rotate in either direction depending on the direction of the current flow.

Fig. 5 illustrates an exemplary scanning mirror system 500 that can include a fast axis component, a slow axis component, a mirror 302, a bracket 502, and a yoke 504. The fast axis component includes a tensioner 506 and a coil 508. The slow shaft component includes a tensioner 510, a sensor 512 (e.g., a hall effect sensor), a magnet 514 (e.g., for sensing rotation), a coil 516 (e.g., copper wrap), a magnet 518, and a flexure 520. The exemplary flexure 520 may be made of beryllium copper (BeCu). In some implementations, the curve 520 may be approximately 0.003 inches. In some embodiments, the bends 520 may be or include parallel wire bundles. The diameter of the beam may be about 0.008 inches. In operation, an electrical signal (e.g., voltage and/or current) may be applied to the slow axis coil 516 to control rotation of the coil, which drives rotation of the slow axis (e.g., vertical axis in fig. 5) of the scanning mechanism.

Fig. 6A-6C illustrate various views of an exemplary fast axis 600 for a scanning mirror system. The example fast axis 600 may include a single coil 602, a flexure 604, a magnet 606, and a sensor 608 (e.g., a hall effect sensor). The flexure 604 may be made of spring steel (e.g., approximately 0.004 inches thick). Alternatively, the bends 404 may be or include parallel wire bundles (e.g., bundles having a diameter of about 0.008 inches). One or more spacers 610 or bushings may be included between the flexure 604 and the mirror 302. The hall effect sensor 608 may sense the magnetic body 606 and the magnetic field from the coil 602. A controller coupled to the coil 602 may be configured to send a signal to turn off the coil 602 during the time the hall effect sensor 608 is used to sense the magnet. In some cases, this may occur in a time period on the order of microseconds to nanoseconds. In some implementations, the coil-generated magnetic field may be subtracted from the estimates based on test and experimental calculations. The resonant frequency of the fast axis may depend on the stiffness of the flexure 604 and the total mass and total moment of inertia of the mirror 302, spacer 610, magnet 606, flexure 604, and adhesive.

Fig. 6D illustrates an exemplary scanning mirror system fast axis 650 with a single coil according to another embodiment. The fast axis 650 may include a single coil 652, a flexure 654, a magnet 660, and a sensor 658 (e.g., a hall effect sensor). The bend 654 may be made of spring steel (e.g., about 0.004 inches thick). Alternatively, the bends 654 may be or include parallel wire bundles (e.g., bundles having diameters of approximately 0.004-0.008 inches).

The hall effect sensor 658 can sense the magnetic body 660 and the magnetic field from the coil 652. A controller coupled to the coil 652 may be configured to send a signal to turn off the coil 652 during the time the hall effect sensor 658 is used to sense the magnet. In some cases, this may occur in a time period on the order of microseconds to nanoseconds. In some implementations, the controller may compensate for the presence of the coil-generated magnetic field by subtracting the estimated effect of the coil-generated magnetic field from the measurement sensed by the hall effect sensor 658. The estimation of the effect of the magnetic field generated by the coil may be based on measurements of the magnetic field generated by the coil recorded during the test and/or experimental calculations. The resonant frequency of the fast axis may depend on the stiffness of the flexure 654 and the total mass and total moment of inertia of the mirror 662, magnet 606, flexure 654 and adhesive.

In contrast to the fast axis 600, the hall effect sensor 658 of the fast axis 650 is located within the coil 652. Thus, the hall effect sensor 658 does not sense the magnetic field generated by the power of the feed coil 652. In contrast, the hall effect sensor 658 senses the change in the magnetic field generated by the magnet 660 without sensing the effect of the magnetic field generated by the coil. Instead, the hall sensor 608 of the fast axis 600 is positioned primarily above the coil 602.

Fig. 7 illustrates the operation of an exemplary scanning mirror 302. During operation, the stationary laser 702 is disposed in position a at a 45 ° angle relative to the mirror 302. As an example, if scanning mirror 302 is moved 30 ° (e.g., from position a to position B or position C), laser beam 704 reflected by mirror 302 is moved 60 ° to obtain a field of view of 120 °. In some implementations, the scanning mirror 302 may be moved approximately 22.5 ° (for the 90 ° view) depending on development and application.

Fig. 8 illustrates a side view of a scanning mirror system, wherein a fast axis 300 and a slow axis 400 are illustrated in fig. 3A-4B. One example size 802 of a scanning mirror system is between about 1 to 1.5 inches (e.g., 1.3869 inches (35.23 mm)).

Fig. 9 illustrates a side view of the scanning mirror system 500 (of fig. 5). A first example size 902 of the scanning mirror system is about 1 to 1.1 inches (e.g., 1.0216 inches) and a second example size 904 is about 1.5 to 2 inches (e.g., 1.6186 inches).

As described above, an electrical signal may be applied to (e.g., conducted through) the slow axis coil 516 to control the rotation of the coil, which drives the rotation of the slow axis (e.g., the vertical axis in fig. 9) of the scanning mechanism. Any suitable circuitry may be used to apply an electrical signal to the slow axis coil 516 (e.g., to provide power to the coil 516). In some implementations, the metal wire may be coupled to the positive and negative terminals of the coil to conduct current to and from the coil. However, the scanning mechanism may subject such wires to frequent and significant vibrations and/or torque, which may cause the wires to fail at a relatively high rate.

In some implementations, to reduce reliance on loose wires, portions of the scanning mechanism may be used to conduct electrical signals to the slow axis coil 516 and/or from the slow axis coil 516 (e.g., to provide power to the coil 516). For example, electrical signals may be conducted along electrical path 530 to slow axis coil 516 and from slow axis coil 516. Referring to fig. 9, the driver circuit may provide a slow axis drive signal at node 532. Node 532 may be electrically coupled to coil 516 at node 534 via portion 520b of slow axis flexure 520. The driver signal may propagate through the coil 516 as shown in fig. 9. Coil 516 may be electrically coupled to node 536 via any suitable electrical coupling (e.g., flexible coupling, resilient electrical contact, etc.), and node 536 may be coupled to node 538 via any suitable electrical coupling (e.g., wire or trace). Node 538 may be coupled to ground through portion 520a of slow axis flexure 520.

Referring to fig. 10, in some embodiments, a scanning mirror system 1000 includes a fast axis component, a slow axis component, and a scanning mirror 302. The fast axis component may include a flexure 1004b, a magnet, one or two coils (e.g., wound coils), and one or two sensors (e.g., hall effect sensors). The fast axis may be configured to operate (e.g., vibrate) at a resonant frequency of the scanning mirror mechanism or a portion thereof (e.g., the portion comprising the flexure 1004b, the mirror 302, and the fast axis magnet).

In the example of fig. 10, the curved member 1004b includes two or more wires. The wires may be arranged in bundles such that the wires are substantially parallel to each other. Any suitable strapping device may be used to strap the wires including, but not limited to, cable jackets, combs, flexible wraps, strapping wires, and the like. Flexure 1004B may be coupled to yoke 1064 by any suitable coupling device. In some embodiments, the ends of the flexure 1004b are mechanically coupled to the yoke 1064 by a bushing 1050, the bushing 1050 may be configured to prevent lateral movement of the flexure 1004b relative to the bracket 1006 and/or to help isolate the yoke from vibrations of the fast axis while still allowing the flexure 1004b to move (e.g., bend and/or twist) in response to movement of the fast axis magnet. The magnet may be coupled (e.g., secured) to the flexure 1004b by any suitable device, adhesive, or other coupling mechanism. As described above, depending on the mass of the mirror 302, the mass of the fast axis magnet, the mass of the curved member 1004b, and/or the tension of the curved member 1004b, the curved member 1004b may be designed to move (e.g., bend and/or twist) at a particular frequency. In some implementations, the curved member 1004b can have a thickness of about 0.004-0.008 inches. The curved member 1004b can be tensioned by any suitable tensioning mechanism.

Still referring to fig. 10, the slow axis component may include a flexure 1004a, one or more magnets, one or more sensors (e.g., hall effect sensors), and a bracket 1006. In some implementations, the slow axis is not controlled to move (e.g., vibrate) at the resonant frequency of the scanning mirror system 1000 or a portion thereof. The slow axes may be driven in a determined order to create a scan pattern (refer to the example scan patterns of fig. 17A-17B). The orientation of the slow axis may be 90 ° relative to the orientation of the fast axis. In some embodiments, the slow axis and the fast axis share one or more components. The slow axis may be controlled to be synchronous with the fast axis. The slow axis may be driven at a frequency in the range of 1-30 Hz.

In the example of fig. 10, the curved member 1004a includes two or more wires. The wires may be arranged in bundles such that the wires are substantially parallel to each other. Any suitable strapping device may be used to strap the wires including, but not limited to, cable jackets, combs, flexible wraps, strapping wires, and the like. The curved member 1004a can be mechanically coupled to the bracket 1006 by any suitable coupling device. In some embodiments, the ends of the curved member 1004a are mechanically coupled to the bracket 1006 by a ring 1052, which ring 1052 may be configured to prevent the curved member 1004a from moving laterally relative to the bracket 1006 while still allowing the curved member 1004a to move (e.g., bend and/or twist).

In some implementations, the curved member 1004a can have a thickness of about 0.004-0.008 inches. In some embodiments, the curved member 1004a can be tensioned by the bracket 1006. For example, the curved member 1004a can be installed in the bracket 1006 by resiliently bending the ends 1054 of the bracket toward each other and placing the curved member 1004a in the bracket, with the ring 1052 fixed relative to the bracket 1006. The ends 1054 of the bracket may then be released so that the spring force of the bracket applies tension to the curved member 1004a during operation. This technique for applying tension to the flexure may be referred to herein as "bow tensioning" because the bracket may create an elastic force that applies tension to the flexure in much the same way as a bow applies to a string of a bow. Any suitable mechanism and/or technique may be used to control the motion of the slow axis, including but not limited to the mechanisms and techniques described above.

Fig. 11-14 illustrate an exemplary scanning mirror system slow axis 1100 according to another embodiment. Slow axis 1100 may be referred to herein as a "closed loop controlled slow axis". In some embodiments, the slow axis 1100 uses a shaft 1132 and bearings 1134 instead of flexures to control the rotation of the scanning mirror on the slow axis. Rotation of the shaft 1132 may be controlled by the magnet 1108 (e.g., north/south magnet).

The slow shaft 1100 may include a holder 1106, a magnet 1108, two coils 1110, a sensor 1112, a magnet 1114, a magnet holder 1130, a shaft 1132, a bearing 1134, a washer 1136, and a plate 1150. Coil 1110 may be an air coil. The sensor 1112 may be a hall effect sensor that may sense the deflection of the magnet 1114 (e.g., as described above). One end of shaft 1132 may be pressed into magnet holder 1130. The other end of shaft 1132 may be pressed into holder 1106. The bearing 1134 may be a sleeve bearing (e.g., a plastic sleeve bearing). The gasket 1136 may be a thrust gasket (e.g., a plastic thrust gasket). Plate 1150 may be or include steel.

When the slow axis 1100 is powered (e.g., when power is applied to the coil 1110), the coil can control the angular rotation of the magnet 1108, and thereby the angular rotation of the shaft 1132 and deflection of the scan mirror. The bearings 1134 and thrust washers 1136 may dampen noise and/or vibration caused by the motion of the slow shaft 1100.

Plate 1150 may block the magnetic fields generated by magnet 1108 and coil 1110 so that those magnetic fields do not interfere with the magnet(s) of the fast axis or otherwise affect the operation of the fast axis. In addition, plate 1150 may provide a contact surface for thrust washer 1136. In some embodiments, there may be a magnetic attraction force between plate 1150 and magnet 1108, which may attract magnet 1108 toward plate 1150, thereby positioning slow shaft 1100.

Referring to fig. 13, in some embodiments, the slow shaft 1100 may include a rod 1140 (e.g., a steel rod) that may be located above and below the shaft 1132 and the magnet 1108. When the coil 1110 is not energized, the magnetic force between the magnet 1108 and the rod 1140 may return the slow axis to its centered position.

In some embodiments, slow shaft 1100 may provide strong vibration damping via bearing 1134 and washer 1136. Slow axis 1100 may be highly robust and/or resilient to shock and/or vibration.

The slow axis of the scanning mirror system may be configured to follow a pattern. In some implementations, the pattern may be similar to a Raster scan (see https:// en. Wikipedia. Org/wiki/master_scan). Fig. 15 provides an example of raster scanning to illustrate movement of the scanning mirror mechanism. For example, the horizontal trace corresponds to the fast axis and the vertical trace corresponds to the slow axis. In some implementations, the scanning mirror system may be configured to follow a reverse scan pattern return (see fig. 17A-17B) rather than a vertical retrace back to the top as shown by the raster scan.

Fig. 16A is a graph of angle of an exemplary trace (as described above) as a function of time. A first sub-curve 1602 indicates the horizontal position of the trace; the second sub-curve 1604 indicates the vertical position of the trace; the third sub-curve 1606 represents the row number.

Fig. 16B is a graph of the angle of an exemplary laser trace of an experimental setup of a scanning mirror system.

Fig. 17A to 17B illustrate two views of an exemplary scanning mode for scanning a mirror.

Other embodiments

In an embodiment, aspects of the technology described herein may be directed to or implemented on an information handling system/computing system. For purposes of this disclosure, a computing system may include any instrumentality or aggregate of instrumentalities operable to compute, determine, classify, process, transmit, receive, retrieve, originate, route, switch, store, display, communicate, manifest, detect, record, reproduce, handle, or utilize any form of information, intelligence, or data for business, scientific, control, or other purposes. For example, the computing system may be a personal computer (e.g., a laptop computer), a tablet computer, a tablet, a personal digital assistant (personal digital assistant, PDA), a smart phone, a smart watch, a smart package, a server (e.g., a blade server or a rack server), a network storage device, or any other suitable device, and may vary in size, shape, performance, functionality, and price. The computing system may include random access memory (random access memory, RAM), one or more processing resources, such as a central processing unit (central processing unit, CPU) or hardware or software control logic, ROM, and/or other types of memory. Additional components of the computing system may include one or more disk drives, one or more network ports for communicating with external devices as well as various input and output (I/O) devices, such as a keyboard, a mouse, a touch screen, and/or a video display. The computing system may also include one or more buses operable to transmit communications between the various hardware components.

Fig. 18 depicts a simplified block diagram of a computing device/information handling system (or computing system) according to an embodiment of the present disclosure. It will be appreciated that the functionality illustrated by system 1800 may support various embodiments of an information handling system, although it should be understood that an information handling system may be configured differently and include different components.

As shown in fig. 18, the system 1800 includes one or more central processing units (central processing unit, CPU) 1801 that provide computing resources and control the computer. CPU 1801 may be implemented with a microprocessor or the like and may also include one or more graphics processing units (graphics processing unit, GPU) 1817 and/or floating point coprocessors for mathematical calculations. The system 1800 may also include a system memory 1802, which may be in the form of random-access memory (RAM), read-only memory (ROM), or both.

As shown in fig. 18, a plurality of controllers and peripheral devices may also be provided. The input controller 1803 represents an interface to various input device(s) 1804 such as a keyboard, mouse, or stylus. There may also be a scanner controller 1805 in communication with the scanner 1806. The system 1800 may also include a storage controller 1807 for interfacing with one or more storage devices 1808, each storage device 1808 including a storage medium such as magnetic tape or disk, or an optical medium that may be used to record programs of instructions for operating systems, entities, and applications, which may include implementations of programs that implement aspects of the techniques described herein. According to some implementations, the storage device(s) 1808 may also be used to store data for processing or data to be processed. The system 1800 may also include a display controller 1809 for providing an interface to a display device 1811, which may be a Cathode Ray Tube (CRT), thin film transistor (thin film transistor, TFT) display, or other type of display. The computing system 1800 may also include an automotive signal controller 1812 for communicating with an automotive system 1813. The communication controller 1814 can interface with one or more communication devices 1815, which enables the system 1800 to connect to remote devices through any of a variety of networks including the internet, cloud resources (e.g., ethernet cloud, fibre channel over ethernet (Fiber Channel over Ethernet, FCoE)/data center bridging (Data Center Bridging, DCB) cloud, etc.), local area networks (local area network, LAN), wide area networks (wide area network, WAN), storage area networks (storage area network, SAN), or through any suitable electromagnetic carrier wave signals including infrared signals.

In the illustrated system, all of the major system components may be connected to a bus 1816, which may represent more than one physical bus. However, the various system components may or may not be in physical proximity to each other. For example, the input data and/or the output data may be remotely transmitted from one physical location to another. Additionally, programs that implement aspects of some embodiments may be accessed from a remote location (e.g., a server) over a network. Such data and/or programs may be transmitted by any of a variety of machine-readable media, including, but not limited to: magnetic media such as hard disks, floppy disks, and magnetic tape; optical media such as CD-ROM and holographic devices; a magneto-optical medium; and hardware devices that are specially configured to store or store and perform program code, such as application specific integrated circuits (application specific integrated circuits, ASICs), programmable logic devices (programmable logic devices, PLDs), flash memory devices, and ROM and RAM devices. Some embodiments may be encoded on one or more non-transitory computer-readable media having instructions for one or more processors or processing units to cause steps to be performed. It should be noted that one or more non-transitory computer-readable media should include both volatile and nonvolatile memory. It should be noted that alternative implementations are possible, including hardware implementations or software/hardware implementations. The hardware-implemented functions may be implemented using ASIC(s), programmable arrays, digital signal processing circuits, or the like. Accordingly, the term "apparatus" in any claim is intended to cover both software and hardware implementations. Similarly, the term "computer readable medium" as used herein includes software and/or hardware having a program of instructions thereon, or a combination thereof. In view of these implementation alternatives, it should be appreciated that the figures and accompanying description provide the functional information necessary for one skilled in the art to write program code (i.e., software) and/or fabricate circuits (i.e., hardware) to perform the required processing.

It should be noted that some embodiments may also relate to a computer product with a non-transitory tangible computer-readable medium having computer code thereon for performing various computer-implemented tasks. The media and computer code may be those specially designed and constructed for the purposes of the technology described herein, or they may be of the kind known or available to those having skill in the relevant arts. Examples of tangible computer readable media include, but are not limited to: magnetic media such as hard disks, floppy disks, and magnetic tape; optical media such as CD-ROM and holographic devices; a magneto-optical medium; and hardware devices that are specially configured to store or store and execute program code, such as Application Specific Integrated Circuits (ASICs), programmable Logic Devices (PLDs), flash memory devices, and ROM and RAM devices. Examples of computer code include machine code, such as produced by a compiler, and files containing higher level code that are executed by a computer using an interpreter. Some implementations may be implemented in whole or in part as machine-executable instructions, which may be in program modules that are executed by a processing device. Examples of program modules include libraries, programs, routines, objects, components, and data structures. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.

Those skilled in the art will recognize that no computing system or programming language is critical to the practice of the techniques described herein. Those skilled in the art will also recognize that the various elements described above may be physically and/or functionally separated into sub-modules or combined together.

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of features specific to particular implementations. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Similarly, although operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In some cases, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

Specific embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. For example, the actions recited in the claims can be performed in a different order and still achieve desirable results. As one example, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some implementations, multitasking and parallel processing may be advantageous. Other steps or stages may be provided or may be removed from the process. Accordingly, other implementations are within the scope of the following claims.

Having thus described several aspects of at least one embodiment of this utility model, it is to be appreciated various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of the utility model. Accordingly, the foregoing description and drawings are by way of example only.

Claims (14)

1. A scanner of a LiDAR system, the scanner comprising:

a mirror having a reflective surface configured to redirect the optical signal emitted by the optical emitter;

A first axis scanning system configured to rotate the reflective surface of the mirror about a first axis and relative to the optical emitter, the first axis scanning system controlling a first emission angle of the light signal from the LiDAR system into a field of view of the LiDAR system; and

a second axis scanning system comprising a mount configured to rotate the mount and the reflective surface of the mirror about a second axis and relative to the optical emitter, the second axis scanning system controlling a second emission angle of the light signal from the LiDAR system into the field of view of the LiDAR system,

wherein the first axis scanning system is configured to rotate the reflective surface of the mirror in a positive rotational direction and a negative rotational direction relative to a center position of the reflective surface of the mirror.

2. The scanner of the LiDAR system of claim 1, wherein the optical emitter comprises a laser.

3. The scanner of the LiDAR system of claim 1, wherein the first emission angle is a horizontal emission angle.

4. The scanner of the LiDAR system of claim 3, wherein rotating the reflective surface of the mirror about the first axis changes a horizontal angle of incidence between the reflective surface and a laser signal propagation path from the optical emitter to the reflective surface.

5. The scanner of the LiDAR system of claim 3, wherein the second emission angle is a perpendicular emission angle.

6. The scanner of the LiDAR system of claim 5, wherein rotating the reflective surface of the mirror about the second axis changes a normal angle of incidence between the reflective surface and a laser signal propagation path from the optical emitter to the reflective surface.

7. The scanner of the LiDAR system of claim 1, wherein rotating the reflective surface of the mirror relative to the center position of the reflective surface of the mirror by 22.5 degrees in the positive rotation direction and by 22.5 degrees in the negative rotation direction causes a 90 degree field of view to be scanned.

8. The scanner of the LiDAR system of claim 1, wherein the first axis scanning system is configured to rotate the reflective surface of the mirror at least 30 degrees in the positive rotation direction and 30 degrees in the negative rotation direction relative to the center position of the reflective surface of the mirror.

9. The scanner of the LiDAR system of claim 8, wherein the first axis scanning system is configured to scan a 120 degree field of view by rotating the reflective surface of the mirror at least 30 degrees in the positive rotation direction and 30 degrees in the negative rotation direction.

10. The scanner of the LiDAR system of claim 1, wherein the mirror is flexibly connected to the stand by one or more flexures.

11. The scanner of the LiDAR system of claim 10, wherein the bracket is flexibly connected to a yoke.

12. The scanner of the LiDAR system of claim 1, wherein the first axis scanning system comprises a magnet disposed below a central portion of the mirror.

13. The scanner of the LiDAR system of claim 1, wherein the first axis scanning system is configured to rotate the reflective surface of the mirror at a frequency having a range between 5Hz and 1000Hz, and the second axis scanning system is configured to rotate the reflective surface of the mirror at a frequency having a range between 0.01Hz and 30 Hz.

14. The scanner of the LiDAR system of claim 1, wherein the first axis scanning system is configured to rotate the reflective surface of the mirror at least 22.5 degrees in the positive rotation direction and 22.5 degrees in the negative rotation direction relative to a center position of the reflective surface of the mirror.