Responder and positioning system

Abstract

To prevent the influence of a multipath.SOLUTION: A responder 100 receives a question wave Pt from an interrogator 200, and transmits a response wave Pr to the interrogator 200. The responder comprises: at least one antenna element 101 that receives the question wave Pt; time-series information conversion units 111 to 114 that measure the orthogonal phase amplitude of the question wave Pt received by the antenna element 101, and convert the orthogonal phase amplitude into time-series information; a storage unit 102 that stores the time-series information; and a transmission control unit 103 that controls the antenna element 101 to transmit the response wave Pr on the basis of the time-series information stored in the storage unit 102. The transmission control unit 103 reads out the time-series information in the order reverse to the order according to which the information is stored in the storage unit 102, and generates the response wave Pr.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a transponder and a positioning system. [Background technology]

[0002] Conventionally, various transponders have been used that receive an interrogation wave from an interrogator and transmit a response wave to the interrogator. For example, Patent Document 1 discloses a transponder that communicates with an interrogator by a retrodirective method. In the transponder of Patent Document 1, a received IF signal obtained by down-converting a received RF signal, which is a received wave, is input to a carrier regenerator to generate a carrier wave, and a transmission IF signal, which is a response wave, is generated by a modulator using the generated carrier wave. At this time, the frequency ω of the transmission IF signal is RFr and the frequency of the received RF signal, ω RFt The relationship between ω RFr =-ω RFt In other words, it is possible to generate a conjugate wave of the carrier wave, that is, a radio wave that travels in the opposite direction to the direction in which the received wave arrived. This enables retrodirective communication between the interrogator and the responder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-68089 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the transponder disclosed in Patent Document 1, when receiving an interrogation wave from an interrogator, if there is an object on the path that reflects the interrogation wave, delay spread occurs due to the effect of multipath, dulling the received waveform and affecting reception accuracy. Also, in a conventional general transponder, the received signals are returned while maintaining the order in which they were received, so that, for example, due to multipath, a component corresponding to the direct wave of a later transmitted signal may be returned to the transmitter before the reflected wave of an earlier transmitted signal. [Means for solving the problem]

[0005] In order to solve the above problem, a transponder of the present invention is a transponder that receives a query wave from an interrogator and transmits a response wave to the interrogator, and includes at least one antenna element that receives the query wave, a time series information conversion unit that measures a quadrature phase amplitude of the query wave received by the antenna element and converts the quadrature phase amplitude into time series information, a memory unit that stores the time series information, and a transmission control unit that controls the transmission of the response wave from the antenna element based on the time series information stored in the memory unit, and is characterized in that the transmission control unit reads out the time series information in a reverse order to the order stored in the memory unit to generate the response wave. [Brief description of the drawings]

[0006] [Figure 1] FIG. 2 is a diagram illustrating an example of use of a responder according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram illustrating a configuration of a responder according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a diagram showing the modem and reference signal generator of the transponder in FIG. 2. [Figure 4] 3 is a flowchart showing a process of generating a response wave in the transponder of FIG. 2. [Diagram 5] 3 is a flowchart showing an operation flow of an embodiment of a positioning system including the transponder of FIG. 2; [Figure 6] 3 is a diagram showing the configuration of a robot arm that is an embodiment of a positioning system including the transponder of FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] First, the present invention will be briefly described. In order to solve the above problem, a first aspect of the present invention provides a transponder that receives a query wave from an interrogator and transmits a response wave to the interrogator, the transponder comprising: at least one antenna element that receives the query wave; a time series information conversion unit that measures a quadrature phase amplitude of the query wave received by the antenna element and converts the quadrature phase amplitude into time series information; a memory unit that stores the time series information; and a transmission control unit that controls the transmission of the response wave from the antenna element based on the time series information stored in the memory unit, wherein the transmission control unit generates the response wave by reading out the time series information in a reverse order to the order stored in the memory unit.

[0008] According to this aspect, the response wave is generated by reading out the time series information in the reverse order to the order of the time series information of the interrogation wave stored in the memory unit. That is, the time-reversed wave of the received interrogation wave is transmitted as the response wave. Therefore, by aligning the path of the response wave with the path of the interrogation wave and transmitting the time-reversed wave of the interrogation wave as the response wave, the response wave can be received by the interrogator in a state where the effect of multipath is suppressed.

[0009] A second aspect of the present invention is a responder that is dependent on the first aspect and is characterized in that it includes a reception time determination unit that determines a reference time, which is the time when the antenna element receives a specific signal pattern included in the query wave, based on the time series information stored in the memory unit, and the transmission control unit controls the response wave to be transmitted after a predetermined holding time has elapsed from the reference time.

[0010] According to this aspect, a reply wave is transmitted after a predetermined hold time has elapsed from a reference time, which is the time when the antenna element receives a specific signal pattern included in the interrogation wave, and therefore, a reply wave to the interrogation wave can be suitably transmitted from, for example, a specific one of the multiple transponders.

[0011] The third aspect of the present invention is a responder that is dependent on the first aspect and is characterized in that it comprises a plurality of the antenna elements, the antenna elements being arranged at predetermined intervals along the receiving surface of the responder.

[0012] According to this aspect, the antenna elements are arranged at predetermined intervals along the receiving surface of the transponder, so that the transmission direction of the interrogation wave can be ascertained from the order in which the interrogation wave is received by the array of antenna elements.

[0013] A responder according to a fourth aspect of the present invention is an aspect dependent on the first aspect, and is characterized in that the time series information conversion unit comprises a modulator / demodulator having a first bidirectional mixer, a second bidirectional mixer, and a bidirectional amplifier connected to the antenna element, the first bidirectional mixer, and the second bidirectional mixer, a shifter for shifting a phase by π / 2, a reference signal generator having a local oscillator connected to the first bidirectional mixer and connected to the second bidirectional mixer via the shifter, A / D and D / A converters connected to the first bidirectional mixer and the second bidirectional mixer, and a frequency divider connected to the A / D and D / A converters.

[0014] According to this aspect, the time series information conversion unit includes a first bidirectional mixer, a second bidirectional mixer, a modulator / demodulator having a bidirectional amplifier connected to the antenna element and the first and two bidirectional mixers, a shifter for shifting the phase by π / 2, a reference signal generator having a local oscillator connected to the first bidirectional mixer and connected to the second bidirectional mixer via the shifter, A / D and D / A converters connected to the first and two bidirectional mixers, and a frequency divider connected to the A / D and D / A converters. With this configuration, the quadrature phase amplitude of the interrogation wave can be suitably converted into time series information.

[0015] A positioning system of a fifth aspect of the present invention comprises a responder of any one of the first to fourth aspects, the interrogator, a distance calculation unit that calculates a distance from the interrogator to the responder, and a position measurement unit that measures a position of the responder, wherein the interrogator outputs the interrogation wave including a specific signal pattern, the distance calculation unit calculates the distance from the interrogator to the responder based on a difference between a time when the interrogation wave is transmitted from the interrogator and a time when the interrogator receives the reply wave transmitted from the responder, and a predetermined holding time, and the position measurement unit measures the position of the responder based on the distance.

[0016] According to this aspect, the interrogator outputs an interrogation wave including a specific signal pattern, the distance calculation unit calculates the distance from the interrogator to the transponder based on the difference between the time when the interrogation wave is transmitted from the interrogator and the time when the interrogator receives the reply wave transmitted from the transponder and the predetermined holding time, and the position measurement unit measures the position of the transponder based on the distance. With this configuration, the position of the transponder can be measured accurately.

[0017] A sixth aspect of the positioning system of the present invention is an aspect dependent on the fifth aspect, and is characterized in that it comprises a mechanical body having a movable part and a fixed part, the interrogator being provided on the fixed part, and the responder being provided on the movable part.

[0018] According to this aspect, the interrogator is provided on the fixed part, and the responder is provided on the movable part. With this configuration, the position of the responder provided on the movable part can be accurately measured.

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. A responder 100 of the present invention is a responder that receives a query wave Pt from an interrogator 200 and transmits a response wave Pr to the interrogator 200 (see FIG. 2). First, an example of use of the responder 100 of one embodiment of the present invention will be described with reference to FIG. 1.

[0020] 1, when the responder 100 receives a query wave Pt from the interrogator 200, it receives a direct wave that reaches the responder 100 directly from the interrogator 200, and a reflected wave that reaches the responder 100 after being reflected by an object O from the interrogator 200. In addition, in Fig. 1, the direct wave is designated as direct wave Pt1, the reflected wave that reaches the responder 100 after being reflected only by object O1 is designated as reflected wave Pt2, the reflected wave that reaches the responder 100 after being reflected only by object O2 is designated as reflected wave Pt3, and the reflected wave that reaches the responder 100 after being reflected by both objects O1 and O2 is designated as reflected wave Pt4.

[0021] Generally, the reflected wave transmitted from the interrogator 200 arrives at the transponder 100 later than the direct wave. Furthermore, the same is true when the reply wave Pr transmitted back from the transponder 100 to the interrogator 200 is received by the interrogator 200. For this reason, the radio waves propagated along different paths arrive at different times, or in other words, the components of the direct wave and the components of the reflected wave are mixed, causing the received waveform to become dull, resulting in the so-called multipath effect. In order to suppress such a multipath effect, in addition to reversing the signs of the carrier frequencies of the interrogation wave Pt and the reply wave Pr, there is a method of generating and transmitting a time-reversed wave, which is a conjugate wave in which the phase and complex amplitude of the received radio wave that changes over time are completely time-reversed.

[0022] Therefore, the details of the responder 100 according to an embodiment of the present invention will be described below with reference to Fig. 2 to Fig. 4. First, with reference to Fig. 2, the operation of the responder 100 when it receives a query wave Pt will be described together with the configuration of the responder 100. Fig. 2 shows both the manner in which the responder 100 receives the query wave Pt with a wavelength λ and the manner in which the responder 100 transmits a response wave Pr with a wavelength λ. In detail, the responder 100 receives the query wave Pt from a direction inclined at an angle Θ with respect to the Z direction in Fig. 2, which is perpendicular to the receiving surface of the antenna element 101, by using an array antenna in which the receiving surface of the antenna element 101 is arranged in a plane in the X direction in Fig. 2 and the Y direction perpendicular to the X direction, and the responder 100 transmits the response wave Pr in the opposite direction to the receiving direction.

[0023] The interrogation wave Pt is an electric wave (electromagnetic wave) having a waveform modulated by an appropriate method with various information such as ID (IDENTIFICATION) information, which is an identification number for identifying the responder 100 that receives it, and synchronization information. The modulation method can be selected from phase modulation, amplitude modulation, orthogonal frequency division multiplexing, etc. The carrier waves used as the interrogation wave Pt and the response wave Pr can be microwaves, millimeter waves, terahertz waves, etc.

[0024] The antenna element 101 has the function of receiving the interrogation wave Pt, and a plurality of them are arranged at regular intervals in one dimension (for example, the X direction in FIG. 2) or two dimensions (for example, the X direction in FIG. 2 and the Y direction intersecting the X direction) to form an array antenna. Note that the transponder 100 of this embodiment has an array antenna in which the antenna elements 101 are arranged two-dimensionally, but for ease of explanation, FIG. 2 considers the interrogation wave Pt and the response wave Pr inclined only in the X direction with respect to the Z direction. Here, generally, a patch antenna is mounted on a substrate as an array, and an electric field amplitude distribution A oscillating on the surface of the array antenna is T (x i , t) can be expressed by the following equation (1).

[0025]

number

[0026] where k T is the wave vector of the interrogation wave Pt. i is a vector that points from the origin of the coordinate axis to the position of the ith antenna. ω is the carrier angular frequency of the interrogation wave Pt. The phase difference φ is the difference between the phase of the interrogation wave Pt and the phase of the LO signal, which is a signal output by the local oscillator 112b described later, at the position of the bidirectional mixers 111b and 111c. If the phase of the interrogation wave Pt is modulated, this phase difference φ includes the modulation phase. Although polarization dependency is not particularly mentioned here, a dual-polarized antenna that can independently receive polarization components in two orthogonal directions can also be used if necessary.

[0027] As shown in Fig. 2 and Fig. 3, the modem 111 is connected to each of the antenna elements 101. As shown in Fig. 3, the modem 111 has a bidirectional amplifier 111a and bidirectional mixers 111b and 111c. The modem 111 amplifies an electric signal output from the antenna element 101 by the bidirectional amplifier 111a, and then branches the signal and inputs it to the bidirectional mixers 111b and 111c. As shown in Fig. 3, the bidirectional mixers 111b and 111c are connected to the path 104, and as shown in Fig. 2, the path 104 is connected to the A / D and D / A converter 113.

[0028] 3, the reference signal generator 112 is composed of a local oscillator 112b and a ±π / 2 shifter 112a. The local oscillator 112b has a frequency ω LO The signal oscillates at and branches into two transmission lines 112c. One signal becomes an in-phase LO signal as is, and the other signal becomes an LO signal with a quadrature phase after being delayed by a phase of π / 2 by the ±π / 2 shifter 112a. The signal is then connected with equal-length wiring to prevent phase differences, and distributed to all bidirectional mixers (bidirectional mixers 111b and 111c).

[0029] With this configuration, all bidirectional mixers perform quadrature demodulation with the same phase, and the amplitude A of two orthogonal phase components is obtained as a baseband signal. I (x i ,t), A Q (x i ,t). Hereinafter, the set of both amplitudes will be called "quadrature phase amplitudes." This action is shown using the following equations (2) and (3). Note that in the following equations (2) and (3), ω LO In actual operation, terms including LO Only the terms not including , are left and input to the A / D converter (A / D and D / A converter 113).

[0030]

number

[0031]

number

[0032] Here, the A / D converter (A / D and D / A converter 113) A / D converts the baseband signal in synchronization with a frequency-divided signal of the LO signal that is frequency-divided by a frequency divider 114 connected to the A / D and D / A converter 113 as shown in Fig. 2, and outputs the converted signal to the memory unit 102 shown in Fig. 2. The memory unit 102 increments the write address in synchronization with the frequency-divided signal, and records the signal output by the A / D converter (A / D and D / A converter 113) in chronological order as quadrature phase amplitude data.

[0033] The reception time discriminator 105 shown in Fig. 2 monitors the pattern of data in the memory unit 102. When the identification number of the target transponder 100 is added to the interrogation wave Pt by, for example, phase modulation and transmitted, the data from symbols Sj to Sj+3 in Fig. 2 is stored in the memory unit 102. Here, when the identification number of the transmitted interrogation wave Pt matches the identification number of the transponder 100, the transponder transmits a trigger signal to the transmission controller shown in Fig. 2 at that point in time.

[0034] When the transmission controller 103 detects a trigger signal, it inverts the sign in the ±π / 2 shifter 112a of the reference signal generator 112 to generate a conjugate LO signal that is a time-reversed LO signal. When expressed on an IQ plane, which is a plane defined by an in-phase axis and a quadrature axis, it becomes a wave that rotates in the opposite direction compared to when it was received. At the same time, it decrements the read address of the memory unit 102 in the opposite direction (t2 direction in FIG. 2) to when it was written (t1 direction in FIG. 2), and sequentially reads out the quadrature phase amplitude data and outputs it to the D / A converter (A / D and D / A converter 113).

[0035] The D / A converter (A / D and D / A converter 113) converts the time series data into an analog signal and outputs it to the modem 111. The modem 111 then mixes the output from the D / A converter (A / D and D / A converter 113) with a conjugate LO signal, outputs it to the antenna element 101 through the bidirectional amplifier 111a, and returns the response wave Pr to the interrogator 200. Here, the electric field amplitude distribution A when the response wave Pr is generated is R (x i ,t) is the quadrature phase amplitude A I (x i ,t), A Q (x i , t), it can be expressed by the following equation (4).

[0036]

number

[0037] Here, the sign inversion in the ±π / 2 shifter 112a causes the quadrature component sin(ω LO As a result of this series of processing, the wave vector k of the output response wave Pr is R is the wave vector k at the time of receiving the interrogation wave Pt T It propagates in the opposite direction to

[0038] Strictly speaking, when comparing equation (1) and equation (4), a phase difference of 2φ occurs, and the holding time from the time when the interrogation wave Pt is received to the time when the reply wave Pr starts to be transmitted (holding time t h ) generates an error. If there is a demand for correcting this, a method of correcting it by adjusting the quadrature phase amplitude data stored in the memory unit 102 can be considered. Alternatively, a phase shifter may be provided immediately after the output of the local oscillator 112b for correction. The generated response wave Pr is split into multiple paths 104, each of which propagates in the opposite direction to the interrogation wave Pt, that is, traveling in the opposite direction along the same route, but the same time delay occurs on the outgoing path and the return path, and as a result, they arrive at the interrogator 200 at the same time. As a result, the interrogator 200 can acquire the response wave Pr with suppressed delay spread.

[0039] In this embodiment, the quadrature component obtained by mixing from the query wave Pt is stored as is in the memory unit 102, but instead, the sign of this component may be inverted and stored. In that case, however, the sign of the ±π / 2 shifter 112a is not inverted, and the quadrature component of the opposite sign is read out to generate the response wave Pr. With this method, the formula (4) becomes equivalent, and substantially the same effect as in this embodiment can be obtained.

[0040] As described above, the transponder 100 of this embodiment, which receives the interrogation wave Pt from the interrogator 200 and transmits the reply wave Pr to the interrogator 200, includes a plurality of antenna elements 101 that receive the interrogation wave Pt. In the transponder 100 of this embodiment, a time series information conversion unit is configured with the modem 111, the reference signal generator 112, the A / D and D / A converter 113, and the frequency divider 114 connected to the A / D and D / A converter. The time series information conversion unit measures the quadrature phase amplitude of the interrogation wave Pt received by the antenna elements 101, and converts the quadrature phase amplitude into time series information.

[0041] As described above, the transponder 100 of the present embodiment includes the memory unit 102 that stores time series information, and the transmission control unit 105 that controls the transmission of the response wave Pr from the antenna element 101 based on the time series information stored in the memory unit 102. As described above, the transmission control unit 105 reads out the time series information in the reverse order to the order stored in the memory unit 102 to generate the response wave Pr. With this configuration, the transponder 100 of the present embodiment transmits the time-reversed wave of the received query wave Pt as the response wave Pr. Therefore, the transponder 100 of the present embodiment can cause the interrogator 200 to receive the response wave Pr in a state in which the effect of multipath is suppressed by aligning the path of the response wave Pr with the path of the query wave Pt and transmitting the time-reversed wave of the query wave Pt as the response wave Pr.

[0042] The process of generating the response wave Pr in the transponder 100 of this embodiment will now be described with reference to the flowchart of Fig. 4. First, in step S110, the transponder 100 receives the query wave Pt by the antenna element 101. Next, in step S120, the time-series information converter measures the quadrature phase amplitude of the query wave Pt, and in step S130, converts the quadrature phase amplitude into time-series information. Next, in step S140, the time-series information is stored in the memory unit 102. Then, in step S150, under the control of the transmission controller 105, the time-series information is read out in the reverse order to that stored in the memory unit 102, and the response wave Pr is generated.

[0043] As described above, the transponder 100 of this embodiment includes a plurality of antenna elements 101. In the transponder 100 of this embodiment, the plurality of antenna elements 101 are arranged at a predetermined interval along the receiving surface of the transponder 100. With this configuration, the transponder 100 of this embodiment can determine the transmission direction of the query wave Pt from the order in which the query wave Pt is received by the array of antenna elements 101. By determining the transmission direction of the query wave Pt, the transponder 100 can transmit the response wave Pr in the reverse order to the order in which the query wave Pt is received. However, this configuration is not limited to this. For example, in a configuration in which a directional antenna is provided as the antenna element 101, at least one antenna element 101 may be provided.

[0044] 3, in the responder 100 of this embodiment, the time series information conversion unit includes a modem 111 having a bidirectional mixer 111b as a first bidirectional mixer, a bidirectional mixer 111c as a second bidirectional mixer, and a bidirectional amplifier 111a connected to the antenna element 101 and the bidirectional mixers 111b and 111c. The time series information conversion unit includes a ±π / 2 shifter 112a which is a shifter for shifting the phase by π / 2, and a reference signal generator 112 having a local oscillator 112b connected to the bidirectional mixer 111b and connected to the bidirectional mixer 111c via the ±π / 2 shifter 112a. The time series information conversion unit further includes an A / D and D / A converter 113 connected to the bidirectional mixers 111b and 111c, and a frequency divider 114 connected to the A / D and D / A converter 113. With this configuration, the quadrature phase amplitude of the interrogation wave Pt can be suitably converted into time-series information.

[0045] 2, the transponder 100 of this embodiment includes a reception time determination unit 105 that determines a reference time, which is the time when the antenna element 101 receives a specific signal pattern, such as an identification number, included in the query wave Pt, based on the time series information stored in the memory unit 102. Here, the transmission control unit 103 is configured to be capable of controlling the transmission of the response wave Pr after a predetermined holding time has elapsed from the reference time. Therefore, the transponder 100 of this embodiment can preferably transmit the response wave Pr in response to the query wave Pt from, for example, a specific one of the multiple transponders 100.

[0046] Next, an embodiment of a positioning system 1 using the transponder 100 of this embodiment will be described with reference to Fig. 5. In the positioning system 1 of this embodiment, the interrogator 200 modulates a signal including the identification number of the target transponder 100 in a predetermined manner, generates an interrogation wave Pt, and transmits it to the transponder 100.

[0047] Like the transponder 100 of this embodiment, the interrogator 200 of the positioning system 1 of this embodiment also generates directional waves using an array antenna in which multiple antenna elements 101 are arranged at predetermined intervals along the receiving surface of the transponder 100. When the position of the desired transponder 100 is unknown, it is preferable for the interrogator 200 to scan the direction of the directional wave and retain information on the direction at the time when the response wave Pr is returned.

[0048] Through the above operation, the transponder 100 stores the quadrature amplitude of the interrogation wave Pt as time-series information in the memory unit 102. If necessary, the information in the memory unit 102 may be modified or added prior to the transmission of the reply wave Pr, and noise generated during the transmission and reception process may be removed. When the transponder 100 detects its own station identification number, it transmits the reply wave Pr by reading out the quadrature amplitude from the memory unit 102 in the reverse chronological order of the time-series information. There is a holding time t from the time when reception of the interrogation wave Pt is completed to the time when transmission of the reply wave Pr begins. h However, a delay function may be added as necessary.

[0049] In the positioning system 1 of this embodiment, the interrogator 200 is provided with a distance calculation unit 201 that calculates the distance from the interrogator 200 to the transponder 100, and a position measurement unit 202 that measures the position of the transponder 100. There is no particular limitation on the locations where the distance calculation unit 201 and the position measurement unit 202 are provided, and they may be provided in the transponder 100, or may be provided in a location separate from the interrogator 200 and the transponder 100. When the interrogator 200 determines that reception of the reply wave Pr is complete, it calculates the time between the transmission completion time of the interrogation wave Pt and the reception start time of the reply wave Pr, and the holding time t h from propagation time t p and calculates the distance from the interrogator 200 to the transponder 100. The position of the transponder 100 is calculated from the transmission direction of the interrogation wave Pt and the distance from the interrogator 200 to the transponder 100. Note that when both the interrogator 200 and the transponder 100 are stationary, the propagation time t p and the propagation time t of the response wave Pr p is equal to

[0050] As described above, the positioning system 1 of this embodiment includes the transponder 100, the interrogator 200, a distance calculation unit 201 that calculates the distance from the interrogator 200 to the transponder 100, and a position measurement unit 202 that measures the position of the transponder 100. Here, the interrogator 200 outputs a query wave Pt that includes a specific signal pattern such as an identification number. The distance calculation unit 201 calculates the difference between the time when the interrogator 200 transmits the query wave Pt and the time when the interrogator 200 receives the reply wave Pr transmitted from the transponder 100, as well as a predetermined hold time t h , the distance from the interrogator 200 to the responder 100 is calculated based on the distance. The position measurement unit 202 then measures the position of the responder 100 based on the distance.

[0051] The positioning system 1 of the present embodiment, being configured as described above, can accurately measure the position of the responder 100. When there are multiple interrogators 200, the position of the responder 100 can be measured by the multiple interrogators 200 even if the interrogators 200 do not have directionality, and when there is only one interrogator 200, the position of the responder 100 can be measured as long as the interrogator 200 has directionality. Furthermore, when there is only one interrogator 200, the position of the responder 100 can be measured even if the interrogator 200 does not have directionality, as long as the moving direction of the responder 100 is only one direction.

[0052] Next, an embodiment of a positioning system 1 different from the positioning system 1 shown in FIG. 5, which uses the responder 100 of this embodiment, will be described with reference to FIG. 6. In this embodiment, an articulated robot 10 is installed in the center of the positioning system 1, and the responder 100 is attached to the arm tip 10a. A control device (not shown) is built into the articulated robot 10, and calculates the position of the responder 100 in a multipoint positioning manner from the distance to the responder 100 measured by communicating with eight interrogators 200 (interrogator 200a, interrogator 200b, interrogator 200c, interrogator 200d, interrogator 200e, interrogator 200f, interrogator 200g, interrogator 200h). In this embodiment, each interrogator 200 and the control device are electrically connected by wired communication, but they may be connected by wireless communication.

[0053] Interrogators 200a, 200b, 200c, 200d, 200e, 200f, 200g, and 200h are arranged around the articulated robot 10, have a function of returning a response wave Pr equivalent to that of the transponder 100, and are also capable of measuring the distance between the interrogators 200. By collecting distance information between the interrogators 200 in advance in the control device, an absolute coordinate system within the positioning system 1 can be set, and the position coordinates of all the interrogators 200 can be calculated.

[0054] Since the interrogators 200 can also measure the distance from the responder 100, the position of the responder 100 can also be calculated in the absolute coordinate system. Here, eight interrogators 200 are provided, but if the three-dimensional position of the responder 100 is to be measured, it is sufficient to find unknown variables in three mutually perpendicular axis directions. For this reason, if the interrogators 200 are not all on the same plane, the position of the responder 100 can be calculated with at least four interrogators 200. Furthermore, if all the interrogators 200 are provided outside the movement range of the responder 100, the position of the responder 100 can be calculated with three interrogators 200.

[0055] In the positioning system 1 of this embodiment, an appropriate interrogator 200 can be selected depending on the wireless communication situation. Furthermore, by attaching the transponder 100 to joints other than the arm tip 10a, the positions and movements of the joints and arms of the articulated robot 10 can be measured. Furthermore, in a usage scene targeting a workpiece, the transponder 100 can be attached to a tray on which the workpiece is placed, so that the position of the workpiece can be measured. Furthermore, by operating each motor in the articulated robot 10 and the transport mechanism of the workpiece tray based on information regarding these positions, and at the same time having the transponder 100 track the transmission direction of the interrogation wave Pt, it becomes possible to control a plurality of mechanisms in a coordinated manner.

[0056] The positioning in the absolute coordinate system described above is also effective for setting the initial position, i.e., teaching, which is necessary before the operation of the articulated robot 10. In the conventional articulated robot 10, an encoder is provided at each joint to detect the rotation direction of the joint and the arm, and the final coordinate of the arm tip 10a is estimated. However, as the number of joints increases, the measurement error of the encoder accumulates, and furthermore, the arm and the joints are deflected due to their own weight, which may cause a large deviation from the actual position of the arm tip 10a. In order to improve this, it was necessary to increase the rigidity of the arm itself and the holding force of the reducer. On the other hand, by using the positioning system 1 of this embodiment, even if the initial state of each encoder, etc. is unknown, it is possible to grasp the state of the articulated robot 10 by, for example, attaching the transponder 100 to each part of the articulated robot 10 and measuring the position of the transponder 100 by transmitting the interrogation wave Pt from the interrogator 200.

[0057] Explaining the positioning system 1 of the present embodiment in another way, as shown in FIG. 6, the positioning system 1 of the present embodiment includes a mechanical body 12 having a multi-joint robot 10 as a movable part having an arm, joints, etc., and a fixed part 11 on which the multi-joint robot 10 is installed. The interrogator 200 is provided on the fixed part 11, and the responder 100 is provided on an arm tip part 10a of the multi-joint robot 10 as a movable part. The positioning system 1 of the present embodiment is configured in this way, and can accurately measure the position of the responder 100 provided on the movable part. However, the present embodiment is not limited to this configuration, and depending on the device configuration of the mechanical body 12, for example, the responder 100 may be provided on the fixed part 11, and the interrogator 200 may be provided on the movable part.

[0058] The present invention is not limited to the above-mentioned embodiment, and can be realized in various configurations without departing from the spirit of the present invention. The technical features in the embodiment corresponding to the technical features in each aspect described in the Summary of the Invention can be replaced or combined as appropriate to solve some or all of the above-mentioned problems or to achieve some or all of the above-mentioned effects. In addition, if the technical feature is not described as essential in this specification, it can be deleted as appropriate. For example, instead of an array antenna having multiple antenna elements, a configuration having one directional antenna element such as a parabolic antenna may be used. The present invention can be applied to the control and automatic driving of automatic guided vehicles in factories. [Explanation of symbols]

[0059] 1...positioning system, 10...articulated robot (movable part), 10a...arm tip, 11...fixed part, 12...mechanical body, 100...responder, 101...antenna element, 102...memory unit, 103...transmission controller, 104...path, 105...reception time discriminator, 111...modulator / demodulator (time series information conversion unit), 111a...bidirectional amplifier, 111b...bidirectional mixer (first bidirectional mixer), 111c...bidirectional mixer (second bidirectional mixer) 112...reference signal generator (time series information conversion section), 112a...±π / 2 shifter, 112b...local oscillator, 112c...transmission line, 113...A / D and D / A converter (time series information conversion section), 114...frequency divider (time series information conversion section), 200...interrogator, 200a...interrogator, 200b...interrogator, 200c...interrogator, 200d...interrogator, 200e...interrogator, 200f...interrogator, 200g...interrogator, 200h...interrogator

Claims

1. A responder that receives an interrogation wave from an interrogator and transmits a response wave to the interrogator, at least one antenna element for receiving the interrogation wave; a time-series information converter that measures a quadrature amplitude of the interrogation wave received by the antenna element and converts the quadrature amplitude into time-series information; A storage unit that stores the time-series information; a transmission control unit that controls the transmission of the response wave from the antenna element based on the time-series information stored in the storage unit; Equipped with The responder, wherein the transmission control unit reads out the time series information in a reverse order to the order stored in the memory unit and generates the reply wave.

2. 2. The responder according to claim 1, a reception time determination unit that determines a reference time, which is a time when the antenna element receives a specific signal pattern included in the interrogation wave, based on the time series information stored in the storage unit, The transponder, wherein the transmission control unit controls the transponder so as to transmit the reply wave after a predetermined holding time has elapsed from the reference time.

3. 2. The responder according to claim 1, A plurality of the antenna elements are provided, A transponder, wherein the antenna elements are arranged at predetermined intervals along a receiving surface of the transponder.

4. 2. The responder according to claim 1, The time series information conversion unit a modulator / demodulator including a first bidirectional mixer, a second bidirectional mixer, and a bidirectional amplifier connected to the antenna element, the first bidirectional mixer, and the second bidirectional mixer; a reference signal generator including a shifter for shifting a phase by π / 2 and a local oscillator connected to the first bidirectional mixer and connected to the second bidirectional mixer via the shifter; an A / D and D / A converter connected to the first bidirectional mixer and the second bidirectional mixer; a frequency divider connected to the A / D and D / A converters; A responder comprising:

5. A responder according to any one of claims 1 to 4, The interrogator; a distance calculation unit that calculates a distance from the interrogator to the responder; a position measurement unit that measures the position of the transponder; Equipped with The interrogator outputs the interrogation wave including a specific signal pattern, the distance calculation unit calculates a distance from the interrogator to the transponder based on a difference between a time when the interrogator transmits the interrogation wave and a time when the interrogator receives the response wave transmitted from the transponder, and a predetermined holding time; A positioning system, wherein the position measurement unit measures the position of the transponder based on the distance.

6. 6. The positioning system according to claim 5, A mechanical body having a movable part and a fixed part, the interrogator is provided on the fixed part, A positioning system, wherein the responder is provided on the movable part.

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