Control System

Abstract

To provide a control system that significantly reduces labor of setting a phase control voltage for a radiation element array, when compared with conventional ones.SOLUTION: A control system 1 includes: a plurality of antenna elements 30 that emit signals by electromagnetic waves; a phase shifter 20 that changes a signal phase entering the antenna elements 30; and a phase shifter controller 40 that determines a parameter to control the phase shifter 20. The phase shifter controller 40 includes a set value generation part 41 which preliminarily learns so that a signal indicating a target beam shape which is a target shape of a beam emitted by the plurality of antenna elements 30 is included in the input data and a set value of forming the target beam shape by the plurality of antenna elements 30 is included in output data.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a control system. [Background technology]

[0002] There is an optical coupler that inputs optical signals from multiple optical input lines and outputs an optical signal that is internally combined. Non-Patent Document 1 discloses a technology in which M-channel optical input lines are combined with a 1-channel optical output line by a first-stage optical coupler, the 1-channel optical output line is branched into 3-channel optical output lines by an optical distributor, the 2-channel optical output lines after the branching are combined with the 1-channel optical output line by a second-stage optical coupler, and the optical output intensity after the combination is observed with a photodiode, thereby estimating the phase relationship of the input optical signals. It is known that when the phases of the optical signals input to each optical input line are all aligned, the output of the photodiode becomes maximum. Thus, by checking the maximum value of the photodiode output in advance, it is possible to determine whether the phase relationship of each current input signal is completely in phase. Then, based on whether the phase relationship is completely in phase, a parameter for correcting (controlling) the phase relationship can be estimated.

[0003] A system in which M channel optical input lines are each connected to a different phase shifter and optical emitting element (OPA (Optical Phased Array) antenna element), and the beam emitted from an optical emitting element array (OPA antenna) can be controlled by controlling the phase of the light input to the optical emitting element with each phase shifter, is called an OPA. The shape of the beam emitted from the OPA is determined by the phase of the signal input to each optical input line. The control voltage to determine the phase was set manually by an operator by observing the shape (beam form) of the beam emitted from the OPA with a camera to obtain the desired beam form. This setting process was repeated as many times as the number of desired beam forms, and when in use, the control voltage setting value corresponding to the desired beam form was given to the phase controller. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Tin Komljenovic and Paolo Pintus, “On-chip calibration and control of optical phased arrays”, Optics Express, Vol.26, No.3, 3199, 2018. Summary of the Invention [Problem to be solved by the invention]

[0005] However, when a beamform is formed by emitting signals from multiple radiating element arrays, such as an OPA, the setting of the control voltage to determine the phase is largely dependent on the operator's experience and takes time. Furthermore, the work of setting the control voltage of the radiating element array increases as the number of desired beamforms increases. Furthermore, a beamform corresponding to a control voltage that has not been set cannot basically be generated, and even if the environmental temperature or the emission wavelength of the laser diode during the setting work is different, the same beamform cannot be generated from the radiating element array, even with the same control voltage.

[0006] The present invention has been made in consideration of the above-mentioned points, and has an object to provide a control system that significantly reduces the labor required for setting a phase control voltage for a radiating element array compared to the conventional art. [Means for solving the problem]

[0007] The control system of claim 1 of the present invention comprises a plurality of radiating elements that radiate signals by electromagnetic waves, a phase shifter that changes the phase of a signal input to each of the radiating elements, and a phase shifter controller that determines parameters for controlling the phase shifter, wherein the phase shifter controller includes a setting value generation unit that has been pre-trained so that input data includes a signal indicating a target beam shape, which is a target shape of a beam radiated by the plurality of radiating elements, and output data includes a setting value that forms the target beam shape by the plurality of radiating elements.

[0008] The control system of claim 2 of the present invention is the control system of claim 1, wherein the setting value generation unit uses a signal indicating a beam shape formed by a plurality of the radiating elements as at least a part of the input data, uses a plurality of the setting values ​​when the beam shape that becomes the input data is formed as at least a part of the teacher data, and is pre-trained based on at least a portion of the error between the output data and the teacher data, or so that the output data and the teacher data match, using a learning dataset which is a collection of pairs of the input data and the teacher data.

[0009] The control system of claim 3 of the present invention is the control system of claim 2, wherein the signal indicating the beam shape contained in the input data is a signal indicating the beam shape when multiple setting values ​​contained in the teacher data are randomly generated.

[0010] The control system of claim 4 of the present invention is the control system of claim 3, wherein the signal indicating the beam shape contained in the input data is a signal indicating the beam shape when multiple setting values ​​contained in the teacher data are randomly generated within a limited range.

[0011] The control system of claim 5 of the present invention is any one of the control systems of claims 1 to 4, wherein the radiating element is a light radiating element that radiates light into space as the electromagnetic wave, and the setting value generation unit has been trained in advance so that a setting value that causes a target light beam shape to be formed as the target beam shape by a plurality of the light radiating elements is included in the output.

[0012] The control system of claim 6 of the present invention is the control system of claim 5, wherein the input data includes at least one of the temperature of a location that affects the shape of the beam, the wavelength of the light source of the light, the emission intensity of the light source, and the polarization direction of the light.

[0013] The control system of claim 7 of the present invention is the control system of claim 6, wherein the temperature of the location that affects the shape of the beam is at least one of the temperature of the light source, a temperature related to the light emitting element, a temperature related to a phase shifter that shifts the phase of the light, and the temperature of the environment in which the light emitting element is present. Effect of the Invention

[0014] According to the present invention, it is possible to provide a control system that significantly reduces the labor required for setting a phase control voltage for a radiating element array, as compared to the conventional art. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a diagram illustrating a conventional method for setting a control voltage. [Diagram 2] 1 is a diagram illustrating an example of the configuration of a light beam control system according to an embodiment of the present invention. [Diagram 3] 11 is a diagram illustrating an example of creating a learning data set for training a setting value generating unit. FIG. [Figure 4] 11 is a diagram illustrating a learning method of the setting value generating unit using a learning data set. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Before describing the embodiments of the present invention in detail, the background to how the embodiments of the present invention were arrived at will be described.

[0017] Figure 1 is a diagram explaining a conventional method for setting control voltages. The shape of the beam radiated from a multiple radiating element array such as an OPA is determined by the phase of the signal input to each radiating element array. Figure 1 illustrates an OPA antenna as the radiating element array. Light from a laser diode (LD), each of whose phases has been changed by a phase shifter (PS), is input to the OPA antenna.

[0018] In the preparation stage, the PS control voltage for determining the amount of phase shift by the phase shifter was set manually on a table by an operator by observing the beam form (FFP: Far Field Pattern) of the beam emitted from the radiating element array with an observation device such as a camera to obtain the desired beam form. This setting work was repeated as many times as the number of desired beam forms. Then, in the use stage, the setting value of the control voltage corresponding to the desired beam form was read from the table and given to the phase shifter.

[0019] However, when a beamform is formed by radiating signals from a multiple radiating element array, such as an OPA antenna, the task of setting the control voltage depends largely on the operator's experience and is time-consuming. The labor required for the setting task increases as the number of radiating elements increases. Furthermore, the labor required for setting the control voltage for the radiating element array increases as the number of desired beamforms increases.

[0020] Furthermore, it is basically difficult to generate a beam form corresponding to a control voltage that has not been set, and even if the environmental temperature during the setting work or the emission wavelength or emission intensity of the laser diode is different, the same beam form cannot be generated from the radiating element array even with the same control voltage. Also, since the emission wavelength or emission intensity of the laser diode varies depending on the temperature, the same beam form cannot be generated from the radiating element array if the temperature is different even with the same control voltage. In other words, the conventional setting method is not robust against fluctuations in temperature, emission wavelength, emission intensity, etc.

[0021] When creating the table, it is possible to obtain an approximate formula for the relationship between the FFP and the control voltage once the relationship between the FFP and the control voltage has been grasped to some extent. However, FFP shapes are diverse, and it is practically difficult to establish an approximate formula that can comprehensively compensate for fluctuations in the environmental temperature and emission wavelength.

[0022] In view of the above, the present inventors have conducted extensive research into a technique that can significantly reduce the amount of work required to set a phase control voltage for a radiating element array, as compared to the conventional technique. As a result, the present inventors have devised a technique that can significantly reduce the amount of work required to set a phase control voltage for a radiating element array, as described below.

[0023] Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same or equivalent components and parts are given the same reference numerals. In addition, the dimensional ratios of the drawings are exaggerated for the convenience of explanation and may differ from the actual ratios.

[0024] Fig. 2 is a diagram showing an example of the configuration of a light beam control system according to this embodiment. The light beam control system 1 shown in Fig. 2 is an example of a control system of the present invention. The light beam control system 1 includes a laser diode 10, a phase shifter 20, an antenna element 30, and a phase shifter controller 40.

[0025] A laser diode 10 outputs light (hereinafter referred to as an optical signal) with a predetermined intensity and frequency. The optical signal output from the laser diode 10 is divided into multiple parts and input to a phase shifter 20. The phase shifter may also be called a phase controller, a phase modulator, a phase shifter, or the like.

[0026] The phase shifter 20 changes the phase of the optical signal output from the laser diode 10 by a predetermined amount. In the example of Fig. 2, the optical signal output from the laser diode 10 is distributed into M lines. The phases of the optical signals output from the phase shifters 20 are φ1 to φ M and the optical signals are input to the antenna elements 30, respectively.

[0027] The antenna element 30 is an example of a radiating element of the present invention. A plurality of antenna elements 30 arranged in a row constitutes a radiating element array. The antenna element 30 can change the direction (azimuth, angle) and shape of the beam radiated from the antenna element 30 based on the phase relationship of the input optical signal. That is, the antenna element 30 functions as an optical scanner. This is called an optical phased array or optical phased array (OPA) type optical scanner.

[0028] The phase shifter controller 40 determines a parameter for controlling the phase shifter 20. The parameter for controlling the phase shifter 20 is a control voltage corresponding to the amount of change in the phase of the phase shifter 20. Since there are M phase shifters 20, there are also M parameters determined by the phase shifter controller 40. The parameter for controlling the phase shifter 20 may be, for example, a current or a power other than the control voltage. Furthermore, since the parameter depends on the specifications of the phase shifter 20, any parameter that can change the phase is not limited to voltage, current, and power, and may be used.

[0029] The phase shifter controller 40 includes a set value generating unit 41 that has been trained in advance so that input data includes a signal indicating a target beam shape, which is a target shape of a beam radiated by the antenna elements 30, and output data includes a set value for forming the target beam shape by the multiple antenna elements 30. Note that while the target beam shape in Fig. 2 is a beam with one peak, the target beam shape may also be a beam shape with two or more peaks. When the target beam shape is a beam shape with two or more peaks, the heights of the peaks may all be the same or different.

[0030] The set value generating unit 41 is trained in advance using any learning method, for example, a deep neural network (DNN). The set value generating unit 41 may use a broad machine learning technique, for example, a support vector machine (SVM) technique. The input data of the set value generating unit 41 may include information on the temperature measured by the thermometer 50, the emission wavelength of the laser diode 10, and the emission intensity of the laser diode 10, in addition to the target beam shape. The temperature measured by the thermometer 50 may be the temperature of the antenna element 30 itself, the temperature around the antenna element 30, or the temperature at a predetermined position on the substrate on which the antenna element 30 is provided. The temperature measured by the thermometer 50 may also be the temperature of the phase shifter 20. Furthermore, the temperature measured by the thermometer 50 is not limited to the temperature related to the antenna element 30 or the phase shifter 20, but may be the temperature of other components constituting the OPA, or the overall temperature of the optical beam control system shown in FIG. 2, such as the temperature of the chip or substrate on which the OPA is mounted, or the temperature of the environment in which the OPA exists. That is, any temperature that affects the relationship between the parameters of the phase shifter 20 and the beam shape is subject to the temperature measurement by the thermometer 50. The temperature information input to the set value generating unit 41 may be any one of the above-mentioned ones or may be a combination of them.

[0031] An example of creating training data for training the setting value generating unit 41 is shown. In this embodiment, the training data is also referred to as a training data set. FIG. 3 is a diagram for explaining an example of creating a training data set for training the setting value generating unit 41. FIG. 3 shows an example in which there are M phase shifters 20 and M antenna elements 30. Note that the training data set may be created by an information processing device not included in the optical beam control system 1.

[0032] The phase shifter controller 40 generates M random parameters (voltages) and outputs the voltages V PS_1 , V PS_2 , , ,V PS_M Apply a voltage V PS_1 , V PS_2 , , ,VPS_M Putting these together gives the voltage V PS_m Here, the phase shifter controller 40 may be any one that can generate M random parameters within the rated range of the phase shifter 20. Then, the phase shifter 20 is supplied with a voltage V PS_m The shape of the beam (FFP) emitted from the antenna element 30 when is applied is observed by a camera.

[0033] Since the parameters generated by the phase shifter controller 40 are random, the shape of the beam emitted from the antenna element 30 is not regular, and it is highly likely that the beam will have an unpredictable and irregular shape. PS_m and the shape of the beam emitted from the antenna element 30 (FFP) are combined to form one learning data set. By repeating this process N times, N learning data sets are obtained. The number N can be, for example, several thousand to several tens of thousands, or even more.

[0034] When generating the learning data set, the temperature T measured by the thermometer 50 and the emission wavelength λ and emission intensity D of the laser diode 10 may be changed. By changing the temperature T and the emission wavelength λ and emission intensity D of the laser diode 10 N times, N data sets {V PS_m ,λ,T,D,FFP} n The data set is V PS_m , λ, T, D, FFP are not necessarily all necessary, and V PS_m , λ, T, D, or FFP. The temperature T of the data set may be two or more types.

[0035] Next, a learning method of the setting value generating unit 41 using the generated learning data set will be described. Fig. 4 is a diagram for explaining the learning method of the setting value generating unit 41 using the learning data set.

[0036] In a training dataset, λ n , T n , D n , FFP nis input to the set value generating unit 41, and the set value generating unit 41 outputs the voltage value V PS_m The predicted value of V PS_m ’ This predicted value V PS_m ’ and the voltage value V in the learning data set PS_m The set value generating unit 41 is trained so that the error between the set value V and the predicted value V is reduced. PS_m ’ and the voltage value V PS_m The setting value generating unit 41 is trained using the training data set so that the values ​​match each other.

[0037] The set value generating unit 41 according to the present embodiment is able to handle various beam shapes to be output by learning using beam shapes based on parameters generated randomly in this way. If the set value generating unit 41 is trained using only specific regular beam shapes, for example beam shapes that protrude only in a specific range, it will only be able to handle specific regular beam shapes. In addition, trial and error by an operator is required to find parameters for obtaining a specific regular beam shape, and it is difficult to prepare a large amount of data set for learning.

[0038] In contrast to this, in the present embodiment, the setting value generation unit 41 is trained using a data set generated using randomly generated parameters, making it possible to accommodate a wider range of shapes compared to training using a specific, regular beam shape.

[0039] When creating a learning data set for training the setting value generating unit 41, parameters that are empirically impossible in past setting operations may be excluded, and the learning data set may be created using only parameters that are randomly generated within the possible range. Also, parameters that are empirically known in past setting operations to radiate a beam with a regular shape may be appropriately incorporated when creating the learning data set.

[0040] 2, the set value generating unit 41 is made to learn in order to determine the shape of the beam from the antenna element 30 functioning as an optical phased array or OPA type optical scanner, but the present invention is not limited to this example. The technology used in the control system 1 according to the embodiment of the present invention can be applied to a phased array type scanner that emits electromagnetic waves including optical or radio wave bands.

[0041] For example, the technology used in the control system 1 according to the embodiment of the present invention can be applied to control of the beam form by an antenna element that radiates radio waves. When the antenna element radiates radio waves, a training data set can be created in the same manner as described above by detecting the beam form using a receiving antenna array.

[0042] As described above, the control system 1 according to an embodiment of the present invention trains the setting value generation unit 41 so that the input data contains a signal indicating a target beam shape, which is the target shape of the beam radiated by the multiple antenna elements 30, and the output data contains setting values ​​for forming the target beam shape by the multiple antenna elements 30.

[0043] That is, in the preparation stage, the control system 1 according to the embodiment of the present invention does not require an operator to manually set the phase shifter 20, and the set value generating unit 41 is trained using DNN or the like. Therefore, according to the embodiment of the present invention, a control system 1 is provided that significantly reduces the labor required for setting the phase control voltage for the radiating element array compared to the conventional case.

[0044] In addition, the control system 1 according to this embodiment has the setting value generation unit 41 trained using DNN or the like, thereby making it possible to realize a robust phase shifter controller 40 even when there are fluctuations in temperature or the wavelength or intensity of the light source. [Explanation of symbols]

[0045] 1. Control System 10 Laser Diode 20 Phase Shifter 30 Antenna elements 40 Phase shifter controller 41 Setting value generator 50 thermometer

Claims

1. A plurality of radiating elements for radiating signals by electromagnetic waves; a phase shifter for changing a phase of a signal input to each of the radiating elements; a phase shifter controller for determining parameters for controlling the phase shifter; Equipped with The phase shifter controller includes a set value generating unit that is pre-trained so that a signal indicating a target beam shape, which is a target shape of a beam radiated by the plurality of radiating elements, is included in input data, and a set value for forming the target beam shape by the plurality of radiating elements is included in output data; The set value generating unit A signal indicating a beam shape formed by a plurality of the radiating elements is at least a part of the input data; The plurality of setting values ​​when the beam shape that is the input data is formed are at least a part of teacher data, The method is performed in advance using a learning data set that is a set of pairs of the input data and the teacher data, based on at least a part of an error between the output data and the teacher data, or so that the output data and the teacher data match, A control system, wherein the signal indicating the beam shape included in the input data is a signal indicating a beam shape when multiple setting values ​​included in the teacher data are randomly generated.

2. The control system according to claim 1 , wherein the signal indicating the beam shape included in the input data is a signal indicating a beam shape when a plurality of setting values ​​included in the teacher data are randomly generated within a limited range.

3. The radiating element is a light radiating element that radiates light as the electromagnetic wave into space, 3. The control system according to claim 1, wherein the set value generating unit is pre-trained so that an output of the set value generating unit includes a set value that causes a target light beam shape to be formed as the target beam shape by the plurality of light emitting elements.

4. The control system according to claim 3 , wherein the input data includes at least one of a temperature of a location that affects the shape of the beam, a wavelength of a light source of the light, an emission intensity of the light source, and a polarization direction of the light.

5. The control system of claim 4, wherein the temperature of the location that affects the shape of the beam is at least one of a temperature of the light source, a temperature associated with the light emitting element, a temperature associated with a phase shifter that shifts the phase of the light, and a temperature of the environment in which the light emitting element is located.

6. The control system of claim 1, wherein the set value is a value of a voltage applied to the phase shifter.

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