Galvano mirror scanner

Abstract

Disclosed is a galvano mirror scanner capable of minimizing a stop section of a mirror by generating a driving waveform for driving a driving motor in consideration of inertia caused by the rotation of the mirror. The disclosed galvano mirror scanner comprises: a mirror; a driving motor for rotating a rotary shaft connected to the mirror; and a motor control unit for generating a driving waveform for driving the driving motor in consideration of the inertia caused by the rotation of the mirror.

Description

Galvano mirror scanner

[0001] The present invention relates to a galvanic mirror scanner capable of minimizing the stopping section of a mirror by generating a driving waveform for driving a driving motor while taking into account the inertia according to the rotation of the mirror.

[0002]

[0003] Recently, as vehicles become more intelligent, research on autonomous vehicles and advanced driver assistance systems (ADAS) is actively being conducted.

[0004] Figure 1 is a drawing showing an example of the detection range of various sensors applied to a vehicle.

[0005] To implement autonomous vehicles or vehicle driver assistance systems, various sensors are essential. These sensors include radar, lidar, cameras, and ultrasonic sensors, as illustrated in Figure 1. In particular, lidar, while somewhat less accurate in object identification, is installed at the front and rear of most autonomous vehicles due to its ability to obtain accurate distance information.

[0006] Meanwhile, in the case of a lidar mounted on a vehicle, it includes a transmitter that generates light and transmits it to an object, a receiver that receives light reflected from the object, and a signal processor that processes signals from the light from the transmitter and receiver. Of course, the transmitter, receiver, and signal processor are provided within a housing, and a transparent window cover is installed in the housing to allow light to enter and exit.

[0007] In particular, methods for scanning light in the transmitter of the rider include mechanical scan, MEMS mirror scan, and galvano scan.

[0008] In the case of the mechanical scanning method, it is easy to increase the detection distance by increasing the size of the mirror using a motor, but the volume is large.

[0009] In the case of the MEMS mirror scan method, the optical paths of the transmitter and receiver do not share the MEMS mirror due to limitations in the mirror size, so the scanning angle is limited. Because the scanning angle is small, the MEMS mirror scan method is expensive because it must apply multiple MEMS configurations, and optical distortion occurs because post optics are applied in the front. In addition, the MEMS mirror scan method is vulnerable to optical noise because the receiver has a wide field of view, and the optical system configuration of the transmitter inevitably becomes complicated due to limitations in the mirror size.

[0010] Meanwhile, the galvano scan method uses a galvanometer scanner and allows for a wider scanning angle than the MEMS mirror scan method.

[0011] Figure 2 is a diagram illustrating the driving waveform of a galvano mirror scanner according to the prior art. Here, the driving waveform may refer to the voltage value of the driving motor that rotates the galvano mirror.

[0012] Referring to Fig. 2, the driving waveform of a galvano mirror scanner according to the prior art can be broadly classified into three sections. Section Ⅰ is a forward voltage increase section for forward rotation of the galvano mirror, and Section Ⅲ is a reverse voltage increase section for reverse rotation of the galvano mirror.

[0013] Section Ⅱ is a voltage maintenance section where the rotation direction of the galvano mirror is changed and the rotation of the galvano mirror is temporarily stopped in Section Ⅱ. Therefore, during this section, no actual scanning operation is performed and object detection may be temporarily stopped, which may increase the possibility of a vehicle accident.

[0014] Therefore, development of a galvano mirror scanner capable of minimizing the stopping section of the galvano mirror is required.

[0015]

[0016] The present invention aims to provide a galvanic mirror scanner capable of minimizing the stopping section of a mirror by generating a driving waveform for driving a driving motor while taking into account the inertia according to the rotation of the mirror.

[0017]

[0018] A galvano mirror scanner according to an embodiment of the present invention,

[0019] A mirror; a drive motor for rotating a rotational axis connected to the mirror; and a motor control unit for generating a drive waveform for driving the drive motor by considering inertia according to rotation of the mirror.

[0020] In a galvano mirror scanner according to an embodiment of the present invention, the driving waveform may be a voltage value waveform of the driving motor that rotates the mirror, and may be a waveform in which the voltage value slope decreases from the beginning of the one-way rotation section of the mirror to the end of the one-way rotation section.

[0021] In a galvano mirror scanner according to an embodiment of the present invention, when the average rotational angular velocity of the mirror during one cycle (T) is referred to as a reference velocity, and a voltage value that makes the reference velocity be referred to as a reference voltage, the rotation section may include at least one acceleration section and at least one deceleration section, and the voltage value may be set so that the acceleration section has a slope greater than the slope of the reference voltage, and the voltage value may be set so that the deceleration section has a slope less than the slope of the reference voltage.

[0022] In a galvano mirror scanner according to an embodiment of the present invention, the rotation section further includes a constant velocity section in which a voltage value is set to have a slope equal to the slope of the reference voltage, and the constant velocity section can be formed between the acceleration section and the deceleration section.

[0023] In the galvano mirror scanner according to an embodiment of the present invention, the driving waveform can be configured in a linear form.

[0024] In a galvano mirror scanner according to an embodiment of the present invention, the driving waveform may be configured in a nonlinear form in the remaining section excluding the constant velocity section.

[0025] In the galvano mirror scanner according to an embodiment of the present invention, the driving waveform may have a nonlinear form in which the slope of the voltage value increases in the acceleration section, and a nonlinear form in which the slope of the voltage value decreases in the deceleration section.

[0026]

[0027] According to a galvanic mirror scanner according to an embodiment of the present invention, the motor control unit generates a driving waveform in which the voltage value is set so that the voltage value gradient becomes smaller from the beginning to the end of the rotation period, thereby reducing the effect of inertia due to the mirror rotation at the point where the rotation direction of the mirror changes, thereby minimizing the mirror pause period. Accordingly, the scanning pause period can be minimized, thereby reducing the possibility of a vehicle accident.

[0028]

[0029] Figure 1 is a drawing showing an example of the detection range of various sensors applied to a vehicle.

[0030] Fig. 2 is a drawing showing the driving waveform of a galvano mirror scanner according to the prior art.

[0031] FIG. 3 is a block diagram illustrating the configuration of a lidar including a galvano mirror scanner according to one embodiment of the present invention.

[0032] FIG. 4 is a drawing illustrating a galvano mirror scanner according to one embodiment of the present invention.

[0033] FIG. 5 is a diagram illustrating a first driving waveform generated by a motor control unit of a galvano mirror scanner according to one embodiment of the present invention.

[0034] FIG. 6 is a diagram illustrating a second driving waveform generated by a motor control unit of a galvano mirror scanner according to one embodiment of the present invention.

[0035] FIG. 7 is a diagram illustrating a computing device according to an embodiment of the present invention.

[0036]

[0037] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0038] The terminology used in the present invention is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In the present invention, it should be understood that the terms such as "comprise" or "have" are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. Hereinafter, a galvano mirror scanner according to an embodiment of the present invention will be described with reference to the drawings.

[0039]

[0040] FIG. 3 is a block diagram illustrating the configuration of a lidar including a galvano mirror scanner according to one embodiment of the present invention.

[0041] According to one embodiment of the present invention, a lidar is a sensor device capable of generating information about an object (OB) outside a vehicle using laser light. According to one embodiment of the present invention, the lidar may be implemented as a motorized device. In the case of a motorized device, it rotates by a motor and can detect objects (OB) around the vehicle.

[0042] In addition, a lidar according to one embodiment of the present invention can detect an object (OB) based on a TOF (Time of Flight) method or a phase-shift method using laser light, and can detect the position of the detected object (OB), the distance to the detected object (OB), the relative speed, etc.

[0043] Additionally, a lidar according to one embodiment of the present invention may be positioned at an appropriate location on the vehicle to detect an object (OB) located in front, behind, or to the side of the vehicle. At this time, the vehicle may be an autonomous vehicle or equipped with an Advanced Driver Assistance System (ADAS), and information detected by the lidar according to one embodiment of the present invention may be used to perform autonomous driving operations or driver assistance operations.

[0044] Specifically, a rider according to one embodiment of the present invention may include a transmitter (100), a receiver (200), and a signal processing unit (300), as illustrated in FIG. 3.

[0045] The transmitter (100) generates laser light and transmits it to an object (OB). The transmitter (100) includes a light source (110) that generates laser light and a galvanic mirror scanner (120) that scans the laser light incident from the light source (110) at various angles.

[0046] The light source unit (110) can generate laser lights of the same wavelength or different wavelengths. For example, the light source unit (110) can generate laser lights having a specific wavelength or having a variable wavelength in the wavelength range of 250 nm to 11 μm, and can be implemented using a small, low-power semiconductor laser diode, but is not limited thereto. The galvano mirror scanner (120) will be described below with reference to FIGS. 4 and 5.

[0047] The receiving unit (200) receives light reflected from the object (OB). For example, the receiving unit (200) may convert light reflected from the object (OB) into an electrical signal (e.g., current) using a photoelectric conversion element such as a photodiode. At this time, the measurement angle of the receiving unit (200) may be referred to as a FOV (Field Of View).

[0048] The signal processing unit (300) processes signals regarding light from the transmitter (100) and the receiver (200). The signal processing unit (300) may include a processor that is electrically connected to the transmitter (100) and the receiver (200), processes the received signals, and generates data regarding the object (OB) based on the processed signals. At this time, the signal processing unit (300) may collect and process data according to the corresponding light to calculate the distance between objects (OB), etc.

[0049] For example, the signal processing unit (300) can convert the output detected by the receiving unit (200) into a voltage, amplify it, and then convert the amplified signal into a digital signal using an analog to digital converter (ADC). In addition, the signal processing unit (300) can perform signal processing on the changed data using a time-of-flight (TOF) method, a phase-shift method, etc. to detect the distance, shape, etc. of an object (OB).

[0050] At this time, the TOF method is a method of measuring the distance from an object (OB) by measuring the time it takes for a pulse signal reflected from an object (OB) within the detection range to arrive at the receiver (200) after a laser pulse signal is emitted from the transmitter (100).

[0051] In addition, the phase-shift method is a method of calculating the corresponding time and distance by measuring the phase change of the signal reflected back from an object (OB) within the detection range after emitting a laser beam that is continuously modulated with a specific frequency from the transmitter (100).

[0052]

[0053] FIG. 4 is a diagram illustrating a galvano mirror scanner according to one embodiment of the present invention, FIG. 5 is a diagram illustrating a first driving waveform generated by a motor control unit of a galvano mirror scanner according to one embodiment of the present invention, and FIG. 6 is a diagram illustrating a second driving waveform generated by a motor control unit of a galvano mirror scanner according to one embodiment of the present invention.

[0054] As illustrated in FIG. 4, a galvanometer mirror scanner (120) according to one embodiment of the present invention includes a mirror (121) connected to a rotation shaft (122), and a drive motor (123) that rotates the rotation shaft (122) to adjust the angle of the mirror (121). That is, the galvanometer scanner (120) can be used as a means for deflecting the angle of laser light to control its optical path. The galvanometer scanner (120) is controlled by the drive motor (123) so that the mirror (121) rotates within a certain angular range.

[0055] At this time, the motor control unit (124) can minimize the stopping section of the mirror by generating a driving waveform such as FIG. 5 or FIG. 6 to drive the driving motor (123) in consideration of the inertia according to the rotation of the mirror (121). At this time, the driving waveform can mean the voltage value of the driving motor (123) that rotates the galvano mirror (121).

[0056] In FIGS. 5 and 6, the time interval 0 to 1 / 2T is a forward (e.g., clockwise) rotation interval of the mirror (121), the time interval 1 / 2T to 1T is a reverse (e.g., counterclockwise) rotation interval of the mirror (121), and T is a period in which the mirror (121) performs forward / reverse rotation at a predetermined angle.

[0057] Each rotation section is divided into at least two sub-sections, and each sub-section can be composed of at least one acceleration section and at least one deceleration section. And, optionally, at least one constant velocity section can be further included. FIG. 5 and FIG. 6 illustrate a case where the forward rotation section (0 to 1 / 2T) and the reverse rotation section (1 / 2T to 1T) are each composed of one acceleration section (A1, A4), one constant velocity section (A2, A5), and one deceleration section (A3, A6). A virtual straight line L1 is a reference speed of the forward rotation section, and a virtual straight line L2 is a reference speed of the reverse rotation section. The reference speed is the average rotation angular speed during one cycle T time, and the reference speeds L1 and L2 are straight lines that differ only in sign (+,-) but have the same magnitude. The voltage value that makes the reference speed is called the reference voltage.

[0058] In Fig. 5 (a), the change in voltage value over time is illustrated as a first driving waveform. The motor control unit (124) sets the voltage value to have a slope greater than the slope of the reference voltage at the beginning of each rotation section (acceleration section), and sets the voltage value to have a slope less than the slope of the reference voltage at the end of the rotation section (deceleration section). Optionally, a constant-velocity section can be set, and the voltage value is set to have the same slope as the slope of the reference voltage in the constant-velocity section. The constant-velocity section is formed between the acceleration section and the deceleration section.

[0059] In Fig. 5 (b), the voltage value change of Fig. 5 (a) is converted into a voltage value slope and depicted. From the slope perspective, the motor control unit (124) sets the voltage value so that the voltage value slope decreases from the beginning to the end of each rotation section. (Regardless of sign)

[0060] Figure 6 illustrates the change in voltage value over time as a second driving waveform. While the driving waveform of Figure 5 is linear throughout the entire section, the driving waveform of Figure 6 is nonlinear in the remaining sections except for the constant velocity sections (A2, A5). Specifically, in the acceleration sections (A1, A4) of the second driving waveform, the voltage value has a nonlinear form with an increasing slope, and in the deceleration sections (A3, A6), it has a nonlinear form with a decreasing slope.

[0061]

[0062] According to the galvanic mirror scanner according to the embodiment of the present invention as described above, the motor control unit (124) generates a driving waveform in which the voltage value is set so that the voltage value gradient becomes smaller from the beginning to the end of the rotation section, thereby reducing the effect of inertia according to the rotation of the mirror (121) at the point where the rotation direction of the mirror (121) is changed, thereby minimizing the temporary stop section of the mirror (121). Accordingly, the scanning stop section can be minimized, thereby reducing the possibility of a vehicle accident occurring.

[0063]

[0064] Fig. 7 is a diagram illustrating a computing device according to an embodiment of the present invention. The computing device (TN100) of Fig. 7 may be a hardware configuration of the motor control unit (124) described herein.

[0065] In the embodiment of FIG. 7, the computing device (TN100) may include at least one processor (TN110), a transceiver (TN120), and a memory (TN130). In addition, the computing device (TN100) may further include a storage device (TN140), an input interface device (TN150), an output interface device (TN160), and the like. The components included in the computing device (TN100) may be connected by a bus (TN170) to communicate with each other.

[0066] The processor (TN110) can execute program commands stored in at least one of the memory (TN130) and the storage device (TN140). The processor (TN110) may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor in which methods according to embodiments of the present invention are performed. The processor (TN110) may be configured to implement procedures, functions, methods, etc. described in relation to embodiments of the present invention. The processor (TN110) may control each component of the computing device (TN100).

[0067] The memory (TN130) and the storage device (TN140) can each store various information related to the operation of the processor (TN110). The memory (TN130) and the storage device (TN140) can each be configured with at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory (TN130) can be configured with at least one of a read-only memory (ROM) and a random access memory (RAM).

[0068] The transceiver (TN120) can transmit or receive wired or wireless signals. The transceiver (TN120) can be connected to a network to perform communication.

[0069] Meanwhile, the present invention can also be implemented as a computer program. The present invention can be implemented as a computer program stored on a computer-readable recording medium, combined with hardware.

[0070] Methods according to embodiments of the present invention may be implemented in the form of readable programs via various computer means and recorded on a computer-readable recording medium. Here, the recording medium may include program commands, data files, data structures, etc., singly or in combination.

[0071] The program commands recorded on the recording medium may be specially designed and configured for the present invention or may be known and available to those skilled in the art of computer software.

[0072] For example, recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CDROMs and DVDs, magneto-optical media such as floptical disks, and hardware devices specifically configured to store and execute program instructions such as ROMs, RAMs, and flash memories.

[0073] Examples of program instructions may include machine language, such as that produced by a compiler, as well as high-level languages ​​that can be executed by a computer using an interpreter, etc.

[0074] Such hardware devices may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

[0075]

[0076] Above, one embodiment of the present invention has been described, but a person having ordinary skill in the art will be able to modify and change the present invention in various ways by adding, changing, deleting or adding components, etc., within the scope that does not depart from the spirit of the present invention described in the claims, and this will also be considered to be included within the scope of the rights of the present invention.

Claims

1. Mirror; A driving motor that rotates a rotation axis connected to the above mirror; A motor control unit that generates a driving waveform for driving the driving motor by considering the inertia according to the rotation of the mirror; A galvano mirror scanner, including:

2. In claim 1, The above driving waveform is a voltage value waveform of the driving motor that rotates the mirror, and is a galvanic mirror scanner in which the voltage value slope becomes smaller as it goes from the beginning of the one-way rotation section of the mirror to the end of the one-way rotation section.

3. In claim 2, When the average rotational angular velocity of the above mirror during one cycle (T) is referred to as the reference velocity, and the voltage value that makes the above reference velocity be referred to as the reference voltage, The above rotation section includes at least one acceleration section and at least one deceleration section, A galvanic mirror scanner, wherein the voltage value of the acceleration section is set to have a slope greater than the slope of the reference voltage, and the voltage value of the deceleration section is set to have a slope less than the slope of the reference voltage.

4. In claim 3, A galvanic mirror scanner, wherein the rotation section further includes a constant velocity section in which a voltage value is set to have a slope equal to the slope of the reference voltage, and the constant velocity section is formed between the acceleration section and the deceleration section.

5. In claim 4, The above driving waveform is a galvanic mirror scanner configured in a linear form.

6. In claim 4, A galvanic mirror scanner in which the above driving waveform is configured in a nonlinear form in the remaining sections excluding the above constant velocity section.

7. In claim 6, A galvanic mirror scanner, wherein the above driving waveform has a nonlinear form in which the slope of the voltage value increases in the acceleration section and a nonlinear form in which the slope of the voltage value decreases in the deceleration section.

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