JP3963179B2 - Positioning device - Google Patents

Description

  The present invention uses a radio wave transmitter that transmits radio waves and an antenna device that receives radio waves from the radio wave transmitter, detects the direction of arrival of radio waves detected by the antenna device, and uses the direction of arrival of radio waves to The present invention relates to a positioning device that obtains the positional relationship between a transmitter and an antenna.

  2. Description of the Related Art Conventionally, a self-propelled device that automatically operates in the direction of arrival of radio waves from a radio wave transmitter carried by a person in an automated guided vehicle or a shopping cart has been proposed (see, for example, Patent Document 1). That is, the self-propelled device automatically operates toward the direction of arrival of radio waves from the radio wave transmitter, and the signal strength for detecting the direction of radio wave arrival is saturated when the distance between the radio wave transmitter and the self-propelled device becomes small. It is described that the self-propelled device is prevented from colliding with an operator having a radio wave transmitter by using the self-propelled device to stop.

Further, in Patent Document 1, it is possible to electronically control the reception directivity in view of the fact that it is difficult to reduce the size and weight when the unidirectional antenna is mechanically rotated to know the direction of arrival of radio waves. It has been proposed to use an electronically controlled array antenna. As an electronically controlled array antenna, non-excitation elements are arranged at equiangular intervals around an excitation element that is a monopole, and the directivity characteristics are changed by changing the reactance value of the variable reactance connected to the non-excitation element. Use what you want.
Japanese Patent Laying-Open No. 2003-177820 (paragraph 0007, FIG. 12)

  On the other hand, an automated guided vehicle used in a factory is known to have map information in an area where the automated guided vehicle travels and travels to reach a target position using the map information. In this type of automatic guided vehicle, map information cannot be used unless the self-location is known within the self-propelled area. In addition, an automated guided vehicle used in a factory requires a relatively high accuracy to detect its own position because a path that can be passed is relatively narrow.

  That is, it is required to detect the self-position of the self-propelled device with relatively high accuracy instead of directing the self-propelled device in the direction in which the radio wave reception intensity is the highest as in the technique described in Patent Document 1. The

  The present invention has been made in view of the above reasons, and an object of the present invention is to provide a positioning device that can detect the relative position between a radio wave transmitter and an antenna device with high accuracy.

The invention of claim 1 comprises a radio wave transmitter that transmits radio waves and an electronic scanning antenna that includes a plurality of parasite elements and changes the reception directivity by switching the load state of the parasite elements. An in-plane including an antenna device for detecting the arrival direction of a radio wave in an antenna coordinate system, which is a three-dimensional polar coordinate set with an antenna as a starting point, and one reference axis of the antenna coordinate system and a radio wave transmitter and a position calculating means for calculating the relative position of the radio transmitters and the antenna in the antenna coordinate system from the arrival direction by using the known information the distance between the antenna and the radio transmitter in the axial direction of the reference axis at an antenna The apparatus includes a first angle formed by a straight line connecting the origin of the antenna coordinate system and the radio wave transmitter with respect to the reference axis, and the reference axis and the radio wave generator. And a second angle formed by the plane including the detector with respect to the other reference axis of the antenna coordinate system at the same time as the arrival direction, and reception for each load state when the load state of the electronic scanning antenna is changed over time A neural network that inputs a vector composed of components of a correlation matrix obtained from intensity and outputs four output values corresponding to the sine and cosine of the first angle and the sine and cosine of the second angle, respectively ; Features.

  According to this configuration, since the relative position between the radio wave transmitter and the antenna is calculated using the arrival direction of the radio wave from the radio wave transmitter and the known information, the radio wave transmitter can be obtained by accurately obtaining the arrival direction of the radio wave. The relative position between the antenna and the antenna can be detected with high accuracy.

In addition, since two directions can be simultaneously measured with respect to the three-dimensional polar coordinates, the relative position in the three-dimensional space can be determined for a short time even when the radio wave transmitter and the antenna move relatively in the three-dimensional space. It becomes possible to calculate by. That is, the position can be tracked almost in real time even with relative movement.

In addition, the output values corresponding to the first angle and the second angle are output using a plurality of reception intensities when the reception directivity is changed by changing the load state of the parasitic element with time. By using the neural network, output values corresponding to the first angle and the second angle can be obtained simultaneously. In addition, by learning the neural network according to the usage environment, the relative position between the radio wave transmitter and the antenna can be accurately determined even when the antenna receives not only the direct wave but also the indirect wave from the radio wave transmitter. It becomes possible to ask well.

In particular, since the neural network is configured to output simultaneously four kinds of output values of the sine and cosine of the first angle and the sine and cosine of the second angle, the first information is obtained by combining the four kinds of information. The angle and the second angle can be obtained, and the accuracy and reliability of the result are higher than when the first angle and the second angle are obtained only by the neural network.

According to a second aspect of the present invention, in the first aspect of the invention, the antenna device includes a measuring unit that measures a distance between the antenna and the radio wave transmitter in the axial direction of the reference axis.

  According to this configuration, the distance obtained by the measuring means can be used as the known information, and it is not necessary to provide the known information necessary for obtaining the relative position between the radio wave transmitter and the antenna in advance. Less time is required.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a reference axis that is fixedly set in a space including the radio wave transmitter and the antenna device and that is parallel to the reference axis of the antenna coordinate system is provided. The position detecting means includes a direction detecting means for detecting the direction of another reference axis in the absolute coordinate system, and the position calculating means is based on the coordinate position in the absolute coordinate system of the radio wave transmitter obtained separately and the direction obtained by the direction detecting means. Then, the position of the antenna relative to the radio wave transmitter is obtained in the absolute coordinate system by performing coordinate conversion from the antenna coordinate system to the absolute coordinate system.

  According to this configuration, the position of the antenna in the absolute coordinate system can be obtained.

According to a fourth aspect of the present invention, in the third aspect of the invention, there is provided an inclination preventing means for keeping the reference axis of the antenna coordinate system parallel to one reference axis of the absolute coordinate system.

  According to this configuration, since the tilt prevention unit prevents the tilt of the antenna with respect to the absolute coordinate system, the arrival direction of the radio wave can be accurately obtained.

According to the invention of claim 5, in the invention of claim 3 , an inclination sensor for detecting an inclination angle of the reference axis of the antenna coordinate system relative to one reference axis of the absolute coordinate system, and an inclination angle detected by the inclination sensor And a correction calculation means for correcting the arrival direction of the radio wave from the radio wave transmitter.

  According to this configuration, even when the antenna is inclined with respect to the absolute coordinate system, the arrival direction of the radio wave from the radio wave transmitter can be accurately obtained by the correction calculation.

According to the configuration of the present invention, the relative direction between the radio wave transmitter and the antenna is calculated using the arrival direction of the radio wave from the radio wave transmitter and the known information. There is an advantage that the relative position between the transmitter and the antenna can be accurately detected. In addition, the sine and cosine of the first angle and the sine and cosine of the second angle are obtained by using a plurality of reception intensities when the reception directivity is changed by changing the load state of the parasitic element with time. Since the four output values corresponding to are obtained simultaneously, the accuracy and reliability of the results are higher than when the first angle and the second angle are obtained using only the neural network.

  As shown in FIG. 1, the embodiment described below uses a radio wave transmitter 1 installed at a fixed position and an antenna device 2 that detects the direction of arrival of radio waves from the radio wave transmitter 1. And the relative position of the antenna device 2 are calculated. In order to simplify the explanation, the radio wave transmitter 1 is arranged at a high place, and the antenna device 2 changes the relative height Lv with respect to the radio wave transmitter 1 in a region where the radio wave from the radio wave transmitter 1 can be received. It shall move without. This example corresponds to the case where the antenna device 2 is provided in an automatic guided vehicle that travels on the ground in a factory.

  First, a description will be given of a case where the relative position between the radio wave transmitter 1 and the antenna device 2 is obtained in an antenna coordinate system (coordinate system in which coordinate axes are expressed in lower case letters) where the origin is set to the antenna 21 provided in the antenna device 2. If the antenna 21 does not tilt with respect to the horizontal plane in the antenna coordinate system, the radio wave in the z-axis direction is within a plane including the z-axis, the radio wave transmitter 1 and the antenna 21 that are one reference axis of the antenna coordinate system. The distance between the transmitter 1 and the antenna 21 is the above-described relative height Lv and is known information. Therefore, if the arrival direction of the radio wave from the radio wave transmitter 1 to the antenna 21 is known, the distance Lh in the horizontal plane between the radio wave transmitter 1 and the antenna 21 can be obtained. Here, if the arrival direction φ of the radio wave is obtained as an angle with respect to the z axis, the distance Lh is Lh = Lv · tan φ. If the antenna device 2 moves in a plane parallel to the horizontal plane, this relationship is established regardless of the directions of the x axis and the y axis.

  On the other hand, when used in an automated guided vehicle, if the direction of the automated guided vehicle changes in the space where the automated guided vehicle travels, the plane including the z axis, the radio wave transmitter 1 and the antenna 21 in the antenna coordinate system becomes x. The angle θ with respect to the axis changes, and the direction changes even if the position of the automatic guided vehicle in the absolute coordinate system (the coordinate system in which the coordinate axes are capitalized) set in the space where the automatic guided vehicle travels does not change As a result, the reception state at the antenna 21 changes. Therefore, if the position of the automated guided vehicle in the absolute coordinate system is to be detected, the three-dimensional position of the radio wave transmitter 1 in the antenna coordinate system is obtained by obtaining the angle θ as the arrival direction of the radio wave, and further the absolute coordinate system Coordinate conversion between the antenna and the antenna coordinate system is required. Further, the coordinate position of the radio wave transmitter 1 in the absolute coordinate system is also necessary. When the condition is constrained so that the z-axis of the antenna coordinate system is parallel to the Z-axis of the absolute coordinate system, the x-axis (or y-axis) in the antenna coordinate system and the X-axis (or Y-axis) in the absolute coordinate system If the angle between the two is known, the antenna coordinate system can be transformed into an absolute coordinate system. That is, since the position of the radio wave transmitter 1 in the absolute coordinate system can be separately given as known information, if the direction in which the automatic guided vehicle travels (corresponding to the x axis or the y axis) in the absolute coordinate system is known, the antenna Using the three-dimensional position of the radio wave transmitter 1 in the coordinate system, the position of the antenna 21 in the absolute coordinate system can be specified. Various known techniques can be used as the technique for obtaining the direction in which the automatic guided vehicle travels.

  The above-described example is based on the precondition that the z-axis in the antenna coordinate system is parallel to the Z-axis in the absolute coordinate system. However, as in the case where the automatic guided vehicle moves on an inclined surface, the z-axis in the antenna coordinate system is When tilted with respect to the Z axis of the absolute coordinate system, it is necessary to detect not only the traveling direction of the automatic guided vehicle but also the tilt. For example, if the automatic guided vehicle travels in the y-axis direction, it is necessary to detect a pitch that is an inclination angle around the x-axis and a roll that is an inclination angle around the y-axis. . Since the direction in which the automated guided vehicle travels in the absolute coordinate system is an inclination angle around the z axis, it corresponds to yaw. From this, when the pitch, roll, and yaw are obtained, the coordinate conversion from the antenna coordinate system to the absolute coordinate system is performed. Can be said to be perfect.

  In summary, the following three types of cases can be classified. That is, as a first case, when the distance Lv between the radio wave transmitter 1 and the antenna 21 in the z-axis direction is known information, to obtain the distance Lh in the horizontal plane between the radio wave transmitter 1 and the antenna 21, It is only necessary to know the arrival direction φ of the radio wave arriving at the antenna 21 from the radio wave transmitter 1 with respect to the z axis in the antenna coordinate system. As a second case, when the z-axis in the antenna coordinate system is parallel to the Z-axis in the absolute coordinate system, the position of the antenna 21 in the absolute coordinate system can be obtained by the radio wave coming from the radio wave transmitter 1 to the antenna 21. Not only the arrival direction φ with respect to the z axis in the antenna coordinate system but also the arrival direction θ with respect to the x axis and the x axis (or y axis) in the antenna coordinate system with respect to the X axis (or Y axis) in the absolute coordinate system. The yaw that is the angle to make is necessary. In the third case, the z-axis in the antenna coordinate system may be inclined with respect to the Z-axis in the absolute coordinate system, and the radio wave transmitter 1 is used to obtain the position of the antenna 21 in the absolute coordinate system. The arrival directions φ and θ with respect to the z axis and the x axis in the antenna coordinate system of the radio wave arriving at the antenna 21 and the pitch, roll, and yaw of the antenna coordinate system with respect to the absolute coordinate system are obtained.

  As described above, the antenna device 2 is required to have a function of detecting the arrival direction φ (or φ, θ) of the radio wave to the antenna 21. Therefore, an electronically controlled array antenna (that is, an electronic scanning antenna) that can change the reception directivity is used as the antenna 21. As this kind of electronic scanning antenna, one using the principle of phased array is known. Generally, the antenna 21 based on the principle of phased array has a large amount of calculation for calculating the direction of arrival of radio waves from the radio wave transmitter 1. Become.

  Therefore, as shown in FIG. 2 (a), the antenna 21 is an electronic scanning antenna in which a plurality of parasite elements 21b whose reactance can be switched are arranged around the radiating element 21a at equal intervals (six in the illustrated example). (Hereinafter referred to as “parasite load switching antenna”). In FIG. 2, the radiating element 21a and the parasitic element 21b are indicated by ellipses. However, the figure does not represent the actual element shape, and various element shapes are used for the radiating element 21a and the parasitic element 21b. Can do. For example, the radiating element 21a and the parasitic element 21b can be formed in a post shape or a planar pattern on a printed wiring board.

  As shown in FIG. 2B, the parasitic element 21b has two terminals like the radiating element 21a, and by selecting whether one terminal is opened or grounded via the switch element 21c, The reactance can be changed in two stages. The distance between the radiating element 21a and the parasitic element 21b is set to be slightly shorter than, for example, one half of the wavelength used, and the switching element 21c switches between whether the parasitic element 21b is opened or grounded. It is possible to change the reception directivity around the element 21a. Therefore, when the antenna 21 is used, the switch element 21c provided in each parasitic element 21b is cyclically controlled so that only one of the six parasitic elements 21b is sequentially grounded. The time required for grounding the switch element 21c connected to each parasitic element 21b once (that is, one switching cycle) switches the reception state when the radio wave from the radio wave transmitter 1 is received by the antenna 21. It is set to a short time that does not change within the period.

In order to obtain the three-dimensional position of the radio wave transmitter 1 in the antenna coordinate system using the parasite load switching type antenna, first, the received output x _i (t) obtained at the radiating element 21a when the parasite element 21b is sequentially grounded. A correlation matrix Rxx shown in Equation 2 is generated using a received vector [x (t)] shown in Equation 1 having (i = 1, 2,..., 6) as components. Here, each reception output x _i (t) has a real part and an imaginary part. [X] indicates that x is a vector. Note that the reception output x _i (t), which is a component of the reception vector [x (t)], is not obtained at the same time, but is considered to be obtained at the same time because the switching cycle is short. .

However, E [[x]] represents an ensemble average. There are two methods for evaluating the correlation matrix Rxx and obtaining the direction of arrival of radio waves in the antenna coordinate system: a method using a learned neural network and a method using an evaluation function called an interferometer.

In the case of using a neural network, as shown in FIG. 3, the preprocessing means 22 is provided in the preceding stage of the neural network 23, and the preprocessing means 22 obtains the correlation matrix Rxx from the received vector x (t). Among the components of the correlation matrix Rxx, a vector [b] having the component shown in Equation 3 is generated, and this vector [b] is normalized. The vector [b] has a component in which a real part Re (r _ij ) and an imaginary part Im (r _ij ) are arranged in order with respect to the component on the right side of the main diagonal of the correlation matrix Rxx.

The neural network 23 is an RBF neural network having an input layer, an intermediate layer, and an output layer, and the neurons in the intermediate layer of the neural network 23 are set as shown in Equation 4.

Since the values to be obtained by the neural network 23 are the arrival directions φ and θ of the radio wave shown in FIG. 1, for example, the neural network 23 has two types of output values f ₁ ([x]) and f ₂ ([[ x]), and f ₁ ([x]) = φ, f ₂ ([x]) = θ, and the automatic guided vehicle is set at a plurality of teaching points where (φ, θ) is known. The learning is taught to the neural network 23 by using the received vector [x (t)] obtained by moving. By learning with teaching, the parameters x _j , σ _j ² , and ω _{mj in Equation 5} are learned, and the arrival directions φ and θ at locations other than the teaching point can be obtained. When the neural network 23 learns, regardless of whether the radio wave received by the antenna 21 is a direct wave or an indirect wave from the radio wave transmitter 1, the arrival direction of the radio wave is set to the learned parameters x _j , σ _j ² , and ω _mj. Since φ and θ are folded, the direction of arrival φ and θ is estimated if the indirect wave is stationary even in an environment where the indirect wave exists and does not change with time in the region where the automated guided vehicle travels. be able to.

The neural network 23 does not output two types of output values of the arrival directions φ and θ, but outputs four types f ₁ ([x]) and f ₂ ( [X]), f ₃ ([x]), f ₄ ([x]) output values, and f ₁ ([x]) = cos φ, f ₂ ([x]) = sin φ, f ₃ ([x]) = cos θ, f ₄ ([x]) = sin θ. In this case, for example, each parameter x _j , σ _j ² , and ω _{mj in Equation} 6 may be learned at the teaching point.

If the configuration in which the sine and cosine are respectively output for the arrival directions φ and θ from the neural network 23 is adopted, the arrival directions φ and θ can be obtained by the following equations, as compared with the case where only two types of output values are used. By using a lot of information, the accuracy of obtaining the direction of arrival is increased. I in the following equation is an imaginary unit.
φ = arg {f ₁ ([x]) + if ₂ ([x])}
θ = arg {f ₃ ([x]) + if ₄ ([x])}
As is clear from the above description, when four types of output values cosφ, sinφ, cosθ, and sinθ are output from the neural network 23, it is necessary to perform an operation for obtaining the arrival directions φ and θ separately from the neural network 23. Therefore, the calculation of the above equation is performed using the position calculation means 24 provided at the subsequent stage of the neural network 23 to calculate the arrival directions φ and θ.

  On the other hand, when the arrival directions φ and θ are obtained using an evaluation function called an interferometer, as shown in FIG. 4, an evaluation calculation means 25 for obtaining an evaluation function instead of the neural network 23 shown in FIG. A table 26 in which vector values called steering vectors obtained from the output of the antenna 21 are associated with the arrival directions φ and θ of radio waves is used.

The steering vector is obtained based on an actual measurement value or a theoretical value, and the reception output x (t when the signal vector [s (t)] arrives from the arrival direction (φ, θ) with respect to the reception antenna 21. ) Means [a (φ, θ)] obtained by the following equation.
x (t) = [(U + YZ) ⁻¹ [y _o ]] ^T [a (φ, θ)] [s (t)]
Here, U is a unit matrix, Y is a mutual admittance matrix, Z is an impedance matrix, and [y ₀ ] is a first column vector of the mutual admittance matrix Y. The above equation regards the received output x (t) as a combination of the outputs of the antennas comprising the respective pairs of the radiating element 21a and each parasitic element 21b, and the steering vector [a (φ, θ)] is radiated It can be said that this is a vector having the output of each antenna composed of a pair of element 21a and each parasitic element 21b as a component.

In the configuration shown in FIG. 4, as in the case of using the neural network 23 shown in FIG. 3, the preprocessing means 22 obtains the correlation matrix Rxx from the received vector [x (t)], and the correlation matrix Rxx is evaluated. It becomes an input to the calculation means 25. The evaluation calculation means 25 uses a plurality of steering vectors [a (φ, θ)] obtained in advance for a known direction of arrival (φ, θ) and stored in the table 26, and the evaluation function P _intr shown in _Equation 7 below. Find (φ, θ). The denominator of the evaluation function P _intr (φ, θ) corresponds to the distance between each component of the correlation matrix Rxx and the steering vector [a (φ, θ)] stored in the table 26, and the evaluation function P _intr ( φ, θ) are distributed as shown in FIG. 5, for example, with respect to the arrival directions φ, θ of radio waves from the radio wave transmitter 1. Here, the arrival direction (φ, θ) corresponding to the steering vector [a (φ, θ)] that maximizes the evaluation function P _intr (φ, θ) is the arrival direction φ, It can be regarded as θ.

  In the above-described technique, the two angles φ and θ shown in FIG. 1 are obtained as the arrival directions of radio waves. However, when only the distance Lh shown in FIG. 1 is obtained, only the angle φ needs to be obtained. Therefore, the configuration relating to the angle θ may be omitted. The distance Lh is calculated by the position calculator 24 provided at the subsequent stage of the neural network 23 or the evaluation calculator 25. Here, the distance Lv between the antenna 21 and the radio wave transmitter 1 in the z-axis direction of the antenna coordinate system is the distance h1 from the reference plane such as the floor surface orthogonal to the z-axis to the antenna 21 and the radio wave from the same reference plane. The difference | h2−h1 | from the known distance h2 to the transmitter 1 is used. That is, since it is only necessary to know the distance h1 from the reference plane to the antenna 21, the distance h1 from the reference plane to the antenna 21 is kept constant, or the distance between the reference plane and the antenna 21 is measured using a distance measuring sensor.

  As the distance measuring sensor, a known sensor can be used. For example, a distance measuring sensor configured to intermittently transmit ultrasonic waves toward the floor and convert time from transmission of ultrasonic waves to reception into distance, A distance measuring sensor configured to irradiate the floor with a light beam such as a laser and convert the change in the light receiving position by a position sensor such as PSD to a distance by triangulation, and intensity-modulating the light irradiated to the floor In addition, a distance measuring sensor or the like configured to convert the phase difference of intensity modulation between the irradiated light and the received light into a distance can be used. That is, since the distance measuring sensor measures the distance between the radio wave transmitter 1 and the antenna 21 in the z-axis direction which is one reference axis of the antenna coordinate system, the measuring means 27 for obtaining known information to be given to the position calculating means 24. Function as.

  In the above example, the floor surface is illustrated as the reference surface. However, when the radio wave transmitter 1 is attached to the ceiling surface orthogonal to the z axis, the ceiling surface to which the radio wave transmitter 1 is attached is the reference surface. Then, the distance from the antenna 21 to the ceiling surface can be obtained by the distance measuring sensor, and this distance can be used as the distance Lv.

  When the two angles φ and θ shown in FIG. 1 are used, the three-dimensional position of the radio wave transmitter 1 in the antenna coordinate system can be obtained by using it together with the distance Lv. Therefore, if the coordinate conversion is performed from the antenna coordinate system to the absolute coordinate system, the position of the antenna 21 in the absolute coordinate system can be known using the coordinate position of the radio wave transmitter 1 in the known absolute coordinate system. The coordinate position of the radio wave transmitter 1 in the absolute coordinate system is given to the radio wave transmitter 1 in advance and transferred to the antenna device 2 or the installation position of the radio wave transmitter 1 is held as map information in the antenna device 2. deep. Hereinafter, a technique for obtaining the position of the antenna 21 in the absolute coordinate system will be described.

  As described above, when the z-axis of the antenna coordinate system and the Z-axis of the absolute coordinate system are parallel, it is only necessary to obtain the yaw of the antenna coordinate system with respect to the absolute coordinate system, so the reference set in the XY plane of the absolute coordinate system An azimuth sensor as the azimuth detecting means 28 for detecting the azimuth may be provided, and the direction of the antenna 21 with respect to the reference azimuth obtained by the azimuth sensor may be detected. For example, the reference azimuth can be, for example, north obtained by geomagnetism. Now, assuming that the positive direction of the X axis in the absolute coordinate system is the reference azimuth and the angle is to the left around the origin, in the azimuth sensor, the x axis of the antenna coordinate system is relative to the X axis of the absolute coordinate system. Since the angle θ ′ can be obtained, the direction of the radio wave transmitter 1 in the absolute coordinate system becomes θ + θ ′ by using the arrival direction θ of the radio wave obtained from the output of the antenna 21. That is, the azimuth detecting means 28 gives known information to the position calculating means 24 together with the measuring means 27.

  However, in order for this relationship to be established, the condition that the x-axis and the Z-axis are parallel to each other must be satisfied. Normally, with respect to the XY plane of the absolute coordinate system as the automated guided vehicle travels. Since the antenna 21 is tilted, the reception conditions change when the antenna 21 is tilted, and the arrival directions φ and θ of radio waves cannot be accurately obtained even using the neural network 23 and the evaluation calculation means 25 described above. Accordingly, the tilt angle of the antenna 21 with respect to the absolute coordinate system is detected by the tilt sensor, and a drive device capable of adjusting the tilt angle of the antenna 21 with respect to the XY plane of the absolute coordinate system is provided, and the tilt angle (that is, pitch and roll) is set. It is desirable to perform feedback control so as to be kept at zero. A gyro sensor can be used as the tilt sensor, and a high-speed response can be expected if an electrostrictive element using a piezo effect is used as the driving device. However, when the inclination is relatively small, the correction calculation of the arrival direction of the radio wave can be performed according to the inclination angle. Therefore, the correction calculation means is provided and the correction calculation of the arrival direction of the radio wave is performed using the output of the inclination sensor. You may do it.

  In order to prevent the antenna 21 from tilting with respect to the XY plane, in addition to the configuration in which the drive device is controlled based on the detection result of the tilt sensor, a predetermined inertial mass is given to the antenna 21 to You may employ | adopt the structure supported with an elastic body like a spring. With such a configuration, even when acceleration is applied, such as when an automated guided vehicle climbs over a step, the acceleration acting on the antenna 21 can be relaxed and the inclination of the antenna 21 can be suppressed. In short, a tilt prevention means for preventing the antenna 21 from tilting with respect to the XY plane of the absolute coordinate system is provided, or a correction calculation for the tilt angle is performed.

  The radio wave transmitter 1 described above can be used as long as it transmits radio waves that can be received by the antenna 21 in the area where the automatic guided vehicle travels. It is possible to use radio waves from a fixed station provided for data communication like an access point of a certain wireless LAN. In this case, it is desirable to use the antenna 21 not only for detecting the position of the radio wave transmitter 1 but also as an antenna for data communication. When the antenna 21 is used for both position detection and data communication, an operation of alternately repeating the position detection period and the data communication period in a short cycle may be performed. Since the antenna 21 uses a parasite load switching type antenna, the reception directivity can be controlled, and the radio wave transmitter 1 is used during the data communication period based on the position of the radio wave transmitter 1 detected during the position detection period. If the reactance of the parasitic element is controlled so as to give the reception directivity in the direction in which data exists, noise coming from an unnecessary direction during data communication can be suppressed, and the occurrence of communication errors in data communication can be reduced. be able to.

  The contents of data communication include the control instruction to the automatic guided vehicle, the report of the operation state from the automatic guided vehicle, and transmission of the coordinate position of the radio wave transmitter 1 in the absolute coordinate system. It is possible to grasp the exact position of traveling using the map information. That is, the automatic guided vehicle can travel autonomously using the map information without attaching a tape or the like for guiding the travel route to the floor surface.

  In the example described above, only one radio wave transmitter 1 has been described. However, in the section where the automatic guided vehicle travels, in practice, a plurality of radio wave transmitters 1 are often arranged. That is, the antenna device 2 receives radio waves from a plurality of radio wave transmitters 1 at the same time. In recent years, radio waves used for various other purposes are also included in the frequency band used for data communication such as wireless LAN, so that the antenna device 2 also receives radio waves from other than the radio wave transmitter 1.

  Therefore, each radio wave transmitter 1 is assigned a unique ID (identifier), and the radio wave transmitter 1 transmits a packet with each ID. The antenna device 2 recognizes the ID included in the packet not only at the time of data communication but also at the time of position detection, and detects the position of the radio wave transmitter 1 for each ID. In this way, by using the ID of the radio wave transmitter 1, errors in position detection due to unnecessary radio waves can be suppressed. When radio waves from a plurality of radio wave transmitters 1 can be received simultaneously, the position of the center of gravity is obtained for the position of the antenna 21 obtained based on the radio waves from each radio wave transmitter 1, or a weighting operation (for example, By calculating the position by a weighted average proportional to the received intensity), the position detection accuracy can be improved as compared with the case where the position is determined only for one radio wave transmitter 1. .

  As a technique for reducing the reception of unnecessary radio waves by the antenna 21, it is conceivable to impart directivity to the radio waves transmitted from the radio wave transmitter 1. In general, the route on which the automated guided vehicle travels is a single line except for a branch point or an intersection. Therefore, when the radio wave transmitter 1 is disposed above the traveling route of the automatic guided vehicle and the radio wave transmitter 1 transmits radio waves. If directivity is given to the direction along the travel route, the probability of indirect waves can be greatly reduced, and the antenna device 2 can perform position detection based on direct waves. The accuracy of position detection can be increased as compared with the case where directivity is not given to the radio wave from the radio wave transmitter 1.

  As described above, when the antenna device 2 is provided as a position detecting unit for detecting the position of the automatic guided vehicle in the absolute coordinate system, the automatic guided vehicle is provided with another position detecting unit (a distance to an encoder or an object for detecting a travel distance). It is desirable to mount a laser radar that measures the frequency of the light source and to complement each other. That is, even in a situation where the position cannot be accurately detected by any of the position detection means, the position can be detected by another position detection means. For example, when the rate of change of the position obtained by receiving the radio wave from the radio wave transmitter 1 by the antenna device 2 is equal to or greater than a specified threshold (that is, when the position fluctuates above the specified value within a predetermined short time) ), Or when the rate of change in radio wave reception intensity at the antenna device 2 suddenly changes, it is estimated that there is an obstacle between the radio wave transmitter 1 and the antenna 21, and the position detected by the antenna device 2 is determined. The position detected by other position detection means is used instead. Alternatively, the accuracy of position detection can be increased by applying fuzzy logic or the like to the positions obtained by a plurality of position detection means.

  When the automated guided vehicle actually travels autonomously, it is necessary for the antenna device 2 to receive the direct wave from the radio wave transmitter 1 in the initial state. It is necessary to perform calibration at the position. In addition, after calibration, the antenna 21 (automated guided vehicle) is moved to the teaching point with the antenna 21 held so as not to tilt with respect to the XY plane of the absolute coordinate system, and a direct wave is received. The neural network 23 is learned or the table 26 is set (indirect waves may be present but direct waves can be received).

  In the configuration example described above, the case where the radio wave transmitter 1 is fixed at a fixed position and the antenna device 2 is provided in the automatic guided vehicle has been described. However, the antenna device 2 is fixed at a fixed position and the radio wave transmitter 1 is fixed. Even if the configuration mounted on the automatic guided vehicle is adopted, the position of the automatic guided vehicle in the absolute coordinate system can be detected. In this case, since the antenna 21 is fixed at a fixed position, one coordinate axis of the antenna coordinate system can be made to coincide with a reference azimuth (for example, a positive direction in the X-axis direction) set in the absolute coordinate system. The position of the automatic guided vehicle in the absolute coordinate system can be detected without using a sensor. If the influence of the indirect wave as described above is allowed, the radio wave transmitter 1 may be non-directional, and the pitch of the automatic guided vehicle and the inclination of the roll hardly affect the position detection. On the other hand, a device for preventing the tilt of the antenna 21 and a correction calculation for the tilt are not necessary.

  However, since the position of the automatic guided vehicle is detected by the antenna device 2, it is necessary to notify the position detected by the antenna device 2 to the automatic guided vehicle equipped with the radio wave transmitter 1 by data communication. Therefore, the communication speed of data communication between the radio wave transmitter 1 and the antenna device 2 is determined in consideration of the traveling speed of the automatic guided vehicle, and is required to be relatively high.

  In each of the configuration examples described above, one of the radio wave transmitter 1 and the antenna device 2 is fixed at a fixed position and detects the position of the automatic guided vehicle in the absolute coordinate system. If the other automatic guided vehicle travels following any one of the automatic guided vehicles, the radio wave transmitter 1 is provided in the leading automatic guided vehicle and the automatic guided vehicle follows. The antenna device 2 may be provided in Here, in order to simplify the description, it is assumed that there are two automatic guided vehicles, the radio wave transmitter 1 is mounted on one side, and the antenna device 2 is mounted on the other side.

  In this case, the automatic guided vehicle provided with the antenna device 2 has a distance defined relative to the automatic guided vehicle provided with the radio wave transmitter 1 based on the position of the radio wave transmitter 1 in the antenna coordinate system obtained by the antenna device 2. A travel control means comprising a microcomputer in which a program is set so as to follow the vehicle at intervals and at a specified angle is provided. If the automatic guided vehicle including the radio wave transmitter 1 is caused to travel based on some information, the automatic guided vehicle including the antenna device 2 travels following the automatic guided vehicle including the radio wave transmitter 1.

  As described above, the automatic guided vehicle provided with the radio wave transmitter 1 and the automatic guided vehicle provided with the antenna device 2 may be provided separately, but in this combination, the master-slave relationship is always constant. Therefore, if the antenna 21 is used for both transmission and reception, and the transmission circuit and the reception circuit are connected to the antenna 21 via the antenna switch, the switching of the antenna switch causes switching of the automatic guided vehicle. The master-detail relationship can be changed.

  By adopting such a configuration, a plurality of automatic guided vehicles can know the relative positions of other automatic guided vehicles. In addition, if the position of any automatic guided vehicle in the absolute coordinate system is known, it is possible to know the absolute positions of other automatic guided vehicles. As a result, a plurality of automatic guided vehicles can operate so as to cooperate with each other using position information of other automatic guided vehicles, and a plurality of automatic guided vehicles can be operated in a coordinated manner. However, it is necessary to define the contents of cooperation separately.

  As the antenna 21, other array antennas can be used besides the above-described parasite load switching type antenna. Moreover, although the case where the automatic guided vehicle travels autonomously has been described as an example, the above-described technical idea can be applied to other moving bodies. The above-described preprocessing means 22, position calculating means 24, evaluation calculating means 25, and table 26 can be easily realized by a microcomputer. The neural network 23 may be configured by software simulation using a microcomputer, but is preferably configured by dedicated hardware.

It is principle explanatory drawing of embodiment of this invention. An example of the antenna used for the above is shown, (a) is a schematic configuration diagram, (b) is a principle explanatory diagram of the parasite element. It is a block diagram which shows an example of the antenna apparatus used for the same as the above. It is a block diagram which shows the other structural example . FIG. 5 is a diagram illustrating an operation example of the antenna device illustrated in FIG. 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radio wave transmitter 2 Antenna apparatus 21 Antenna 21a Radiating element 21b Parasite element 23 Neural network 24 Position calculating means 25 Evaluation calculating means 26 Table 27 Measuring means 28 Direction detection means

Claims (5)

A radio wave transmitter that transmits radio waves and an electronic scanning antenna that has a plurality of parasite elements and changes the reception directivity by switching the load state of the parasite elements, and has an antenna that receives radio waves from the radio wave transmitter An axial direction of the reference axis in a plane including an antenna device for detecting the arrival direction of a radio wave in an antenna coordinate system, which is a three-dimensional polar coordinate set as an origin, and one reference axis and a radio wave transmitter of the antenna coordinate system Position calculating means for calculating a relative position between the radio wave transmitter and the antenna in the antenna coordinate system from the direction of arrival using the distance between the antenna and the radio wave transmitter in the known information, and the antenna device includes the antenna coordinate system A first angle formed by a straight line connecting the origin and the radio wave transmitter with respect to the reference axis, and a plane including the reference axis and the radio wave transmitter. A correlation matrix obtained by simultaneously measuring the second angle formed with respect to the other reference axis of the antenna coordinate system as the direction of arrival, and obtaining the received intensity for each load state when the load state of the electronic scanning antenna is changed over time And a neural network that outputs four output values respectively corresponding to the sine and cosine of the first angle and the sine and cosine of the second angle . The positioning apparatus according to claim 1, wherein the antenna apparatus includes a measuring unit that measures a distance between the antenna and the radio wave transmitter in the axial direction of the reference axis. An azimuth detecting means for detecting the azimuth of another reference axis in an absolute coordinate system having a reference axis that is fixedly set in a space including the radio wave transmitter and the antenna device and that is parallel to the reference axis of the antenna coordinate system And the position calculating means performs radio wave transmission by performing coordinate conversion from the antenna coordinate system to the absolute coordinate system based on the coordinate position in the absolute coordinate system of the radio wave transmitter obtained separately and the direction obtained by the direction detecting means. 3. The positioning device according to claim 1, wherein the position of the antenna with respect to the device is obtained in an absolute coordinate system . 4. A positioning apparatus according to claim 3, further comprising tilt prevention means for keeping the reference axis of the antenna coordinate system parallel to one reference axis of the absolute coordinate system . An inclination sensor that detects an inclination angle of the reference axis of the antenna coordinate system with respect to one reference axis of the absolute coordinate system, and a correction calculation of the arrival direction of the radio wave from the radio wave transmitter according to the inclination angle detected by the inclination sensor positioning equipment according to claim 3, characterized in that it comprises a correction arithmetic means for performing.

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