JPH02504113A - Ball position determination device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Eni top l fillet stalk 1 , [Industrial application field] The present invention relates to a pole position detection device, and in particular, to a pole position detection device, in particular when a ball, such as a tennis ball, is This invention relates to a device that detects the position of a drop when it falls on the surface of a court near the inn.

[Conventional technology]

This is a well-known problem for which several solutions have already been proposed. For example, the United States The system disclosed in Patent No. 3.883.860 and Patent No. 4.299.384 When contact occurs between the sensor conductors exposed on the coating surface, It uses a ball with conductive fibers that closes the circuit. But this Their system has the following problems. The balls used in this system are conventional Tennis balls that have been used since and color, surface quality, coefficient of friction and moment of inertia The quality of the surface near the line should also be different for the court. It is necessary to make them different. Moreover, the above circuit is made of aluminum made of tennis rackets or any other electrical conductor, or by falling off the ball. conductive fibers that straddle the sensor conductors on the It needs to be able to be closed even if it is closed.

Additionally, U.S. Patent No. 3.774.194 and U.S. Patent No. 4.664.376 are A system for electromagnetic detection using buried detection coils is shown.

The former patent uses a radio frequency bridge circuit, of which the "arm" One consists of a buried coil, and the circuit is connected to the radio frequency emitted by this buried coil. Detecting a tennis ball containing a tuned resonant electrical circuit.

The latter patent publication discloses an embedded coil that is part of the oscillator's resonator.

The frequency and cue value of this oscillator are essentially the same as when a ball of non-zero permeability is nearby. If there is, it will change.

Conventional configurations have the disadvantage of being sensitive to external influences, and also have the disadvantage of being sensitive to external influences. whether the ball touched the line if it was exactly "parakeet" or "out" is extremely difficult to determine. Rather, the above system simply connects the sensing coil to It only detects whether the ball is near.Furthermore, U.S. Pat. The balls described in No. 194 have essentially different physical properties than normal balls, e.g. For example, they have moments of inertia that require different eigenaxes.

To determine if the ball is "in" or "out", use the calculation ergorizle Therefore, it is necessary to process it. Ball as shown in U.S. Pat. No. 4,664,376 Measuring the presence of in the vicinity will be inaccurate for reasons that will be shown later.

It is an object of the invention to overcome at least one or more of the drawbacks mentioned above.

Summary of the invention According to one form of the invention, the ball position determination device is provided with a transmitter coil and a receiver under the playing surface. coils, these two coils being adjacent to each other under a selected portion of the playing court. They are arranged in a row.

Preferably, each coil is placed next to each other in an overlapping manner.

Two receiving coils allow the receiving coil to cancel signals received from distant field sources. is preferably adjacent to the transmitter coil.

Preferably, the receiving coil substantially cancels out the signals received from the receiving coil.

In the electromagnetic interrogation device of the present invention, a transmitting coil is placed near the court line and below the surface of the court. and a receiving coil are arranged.

The axis of each of these coils is parallel to the coat line, and from these coils The signal is used to detect balls of material with non-zero magnetic permeability.

Some of the latex rubber "filler" additives commonly used in tennis balls Preferably, the ball is replaced with powder particles of a magnetic material with high magnetic permeability, such as ferrite. stomach.

Preferably, the ball is made of latex rubber “filled” which is commonly found in tennis balls. Additives for "Filler" are used for high permeability magnetic materials such as ferrite. Replaced with powder particles.

Preferably, the alternating magnetic field is applied for between 2 microseconds and 200 microseconds through the transmitter coil. Transmitter means are provided for transmitting at a transmission period selected within the range of The ball is received by a receiving coil or group of receiving coils from the ball, and the ball is Reradiate the signal with effect.

Preferably, the signal induced in the receiving coil is synchronously demodulated by detector means. and the low frequency range is filtered. The reference phase of the synchronous demodulator is based on the magnetic field component. or the phase of the magnetic permeability of the ball. You can choose whether to make it at right angles. Then the low frequency filter above and processed for final “in” or “out” evaluation.

Preferably, a plurality of individual receiver coils are provided, each coil being connected to a tennis court. occupies a selected long length of the line below the playing surface as a , this length is formed into an elongated piece on the order of meters. These mentioned above The receiving coil preferably has a proportion of adjacent ends below the length of the coat line. The ends are placed side by side so that they overlap the coil.

This transmitter coil is preferably similarly segmented and extends the length of the line. stomach.

The system described here is capable of solving multiple pre-existing problems. Ru.

First, physical differences; Balls and courts can be made so that they are physically indistinguishable from the standard.

Second, a false trigger occurs when a detectable object crosses a line other than the ball. , can be minimized.

Third, reduced susceptibility to far-field generated electromagnetic interference (E, M, sex.

Both the quadrature and in-phase signals are equally susceptible to electromagnetic interference. That's it However, any significant signal in the quadrature channel represents an erroneous signal. If further, Far magnetic fields are canceled while near fields are not canceled. , if the receive coil circuit is configured, the system is disabled in the far field. can be relatively insensitive to electromagnetic interference compared to systems containing unprotected coils. Ru.

Fourth, accuracy; may include means for determining with reasonable accuracy whether a line has been touched in a given case; . This is not just a magnitude comparison to a fixed value, but rather a percentage or This can be accomplished by the process algorithm part that requires the comparison.

Furthermore, the sensitivity of the same length of the court line but different spaces across the line The ratio or comparison between data from different receive coil circuits having Best to have some. Using data from two different coil signals The final “in”/out evaluation is based on coil depth or ball allowing it to be relatively independent of the magnetic permeability.

Brief description of the drawing To facilitate understanding of the present invention, the following diagrams will be explained.

FIG. 1 shows one transmitter coil, far field and balance according to a preferred embodiment of the invention. At its ends, the arrangement of two receiver coil circuits with equal sensitivity is This is a diagram showing.

FIG. 2 is a plan view of the arrangement of FIG. 1.

FIG. 3 is a schematic diagram showing the circuit configuration in the embodiment of FIGS. 1 and 2. FIG.

In addition, FIG. 4 shows an embedded coil having the configurations shown in FIGS. 1, 2, and 3. A graph showing the waveforms obtained from balls with different trajectories hitting the court on the system. It is f.

Referring to the drawings, a transmitting coil 1 and a receiving coil 2.3 are shown. reception Coil 2.3 is indicated by arrow 4.5.6 for receiver coil 2, For loop 3, wind clockwise and counterclockwise as shown by arrow 7.8. Two independent receiver coil circuits with connected windings. That is, coil 2 effectively consists of three series windings 9.1゛0.11, one with a dia. At the top of the gram, the winding 10 is wound clockwise, and at the middle, it is wound counterclockwise. At the bottom of the diagram, there is a series of clockwise windings.

The coil 3 effectively consists of two series windings 12.13, one winding 1 2 is wound clockwise in the top half of the diagram, and in the benthic part of the diagram; A series of windings 13 are wound clockwise.

The size and number of turns in each winding are induced into each coil from the far field at the transmit frequency. The selected signal is selected such that the detected signal is substantially canceled or becomes zero. to this This substantially reduces the level of electromagnetic interference within the coil circuit. In this specification Therefore, "far field" means a field at least 10 times the width of the coil from the receiver coil. This refers to the magnetic field generated by the earth.

In order to successfully release the above, consider the effect of the spatial impedance of the transfer coil. I have to put it in. For example, if the coil is displaced symmetrically around the diagram, coil 3, each winding having the same number of turns, will act as a transfer coil drive. Balanced to far field regardless of dynamic impedance. On the other hand, the same In one dimension, the windings of coil 2, outer coils 9 and 11 relative to inner coil 10 The number of times the transfer coil 1 is driven depends on the drive impedance of the transfer coil 1. against ball 25 The sensitivity of the receiving coil is highest at both ends of the receiving coil.

To make the sensitivity more uniform, the windings of each coil can be changed as indicated by reference numeral 14. need to be divided.

The signal generated by oscillator 15 is amplified via amplifier 16 and received by coils 2 and 3. When the signal is received, it is amplified by the amplifier 17, then tuned to the transfer frequency, and then A low-pass filter can then be applied. The reference phase of tuned detection is the magnetic permeability of the ball. Both components, one almost in phase with the magnetic flux and one in phase quadrature with respect to the ball's permeability. A tuned detector, a low-pass filter 18, and a quadrature phase shifter 20 are used. It is shown as a tuned detector and low pass filter 19 for quadrature.

The stationary background signal is subtracted at 21.22 and is a function of the change in the coil's magnetic environment. A signal with an intensity of is obtained. The in-phase component is used for further processing, and the quadrature The phase component is useful not only for identifying electromagnetic interference, but also for identifying aluminum It has a different reaction-resistance ratio than balls made from rubber tennis rackets, metal chains on tennis courts, etc. It can also be used for purposes of identification, such as identifying substances possessed.

Data from the receive coil pair is processed by a local microprocessor 25; The processed information reaches a central microprocessor indicated at 28. Similar reception/ A continuous processing circuit is used for coil 2. And the corresponding data is reference number 26 ．． As shown at 27, a common local microprocessor 25 is reached.

Therefore, by introducing the concept of having a transmitting coil and a receiving coil, firstly, The receiver coil is designed to be less susceptible to electromagnetic interference from distant sources or distant areas. can be matched and the accepted signals are checked for resistance and recoil factors However, it is also possible to perform practical identification by accepting only signals within a limited range. It is.

Balls, especially tennis balls, are characterized by their characteristics and ball handling - rebound characteristics. before, so that the properties remain exactly the same except that the ball is essentially magnetically permeable. A small amount of foam mixed into the rubber mixture replaces the same weight of the filler that was in the It has

The reason for using two receiver coils is that if only one receiver coil (e.g. 3), if the tennis ball falls along the lateral border of this coil If you keep the exact position, what should be detected will not appear, therefore this Another separate coil is required to detect the position of the ball.

Of course, the second receiver coil is essentially immune to electromagnetic interference from far-field sources. It must be wound in such a way that it is disabled, but unlike the first coil coil 2 accomplishes this.

Coils arranged as specifically shown in Figure 2 can be of any length, but 23, which would be expected to be located approximately below each line.

Each receive coil is "dead" for the transmit region, i.e. any receive coil The net signal induced by the transmitter coil in the transmitter coil is is substantially minimized due to the selected geometry of. This is a high stability tolerance Power supply for relatively simple electronic components that do not require a large dynamic range. It has air conductivity.

Next, let's discuss how to explain the judgment of ``parakeet'' or ``out.'' . This involves making decisions about a number of different bounce locations, making appropriate decisions about the mark, then store this in the memory of the microprocessor, then the known When the position where the signal is not detected is to be determined, it involves comparing this with the introducing signal.

When a large signal is present at right angles to either coil of the receive coil pair, all signals are Check whether the ball is “in” or “out” by judging whether the varnished ball is “in” or “out.” When the system cannot determine whether the Not done.

FIG. 4 illustrates four waveforms at the output of the low pass filter. Figures 1 and 1 The ball hits the court with different trajectories on the direct-buried coil system with the configuration shown in Figure 2. The background is subtracted from the matching elements. The dotted line is from coil 2 The solid line represents the response and is for coil 3.

The "in"/"out" edge is the boundary between the two windings of the circuit of coil 3, i.e. the second Assuming that it is directly above the center of the figure, in each case the ball's projection is at the bottom of the page. from to the top where the bottom is on the “in” side and the top is on the r out j side. Assume that

The trajectory of the ball from a "high lob" where the ball hits the court almost vertically, exactly When you reach the center of the coil system, the ball is "in" and slightly above the center. , the ball is just "out", but in Figures 4(a) and 4(b), respectively. It is illustrated.

A fast shot where the ball approaches the court almost horizontally and hits the court, grazing the net. The waveforms according to the trajectory of the cut are shown in FIGS. 4(c) and 4(d), and (C) Diagram shows that the ball's "footprint" corresponds to the "in"/"out" edge. Figure 4(d) shows that the ball is just ``out''. ”.

Many algorithms are employed to determine whether the ball is "in" or "out." can be done. Any accurate algorithm spans a range of possible waveforms. Compare waveforms with a waveform dictionary or make a certain ratio or comparison of mutual signal values, i.e., to a constant value. Requires either an algorithm that does not perform magnitude comparisons.

For example, some of these latter algorithms determine the value of . Here, S2 and S3 are the low voltage with stationary signals taken from coils 2 and 3. It is a passing signal, and "ABS (S3J means the absolute value of S3, and K is constant.

If this value is less than a certain value, the ball is considered "out". It will be done. Otherwise, the ball is considered "in" as long as certain other criteria are also met. It will be done. Compare the data of one coil circuit of a pair with the data of the other coil circuit , results are obtained that are relatively independent of the coil voluminousness below the surface and the ball permeability. It will be done.

Also, check that the data is within a certain constraint for further discrimination purposes. This is desirable. For example, if the ball is not created by an obviously impossible trajectory, A signal with a pulse waveform that is too large or too small cannot be accepted. Requires.

If the ball lands near the line near the end of the receiving coil pair and one of the ball's trajectory part of the sensitive band of the receiving coil pair required for accurate determination of ball position. If the coil pair in question and the ball traverse that co By considering data from coil pairs adjacent to the coil pair, the ball is ” or “out”.

For simplicity and high accuracy, adjacent receive coil pairs should be overlapped and placed near the line. For all regions near the coil, all ball positions in the region near the coil are both induce a substantial signal in one coil that can be used to determine The above determination must be made in order to determine whether the Must be.

A central microprocessor to which processed data from each coil pair is sent alerts Once received, the central microprocessor determines where the ball 24 has traversed. Ball 24 selects or combines data from all nearby coil pairs and Make the first decision as to whether the player is out or not.

Due to the presence of magnetically permeable rods in tennis courts with metal reinforced rods, The magnetic field in the vicinity of the rod is thus substantially altered. Furthermore, near the above rod The response to a traversing ball is different from that of the corresponding ball trajectory from the rod. different.

To avoid this undesirable situation, metals made of e.g. A screen may be inserted between the rod and the coil.

The strength of the magnetic field generated by the conducting coil due to the presence of the above screen is and closer to the windings compared to when no screen is present. The area away from the winding is relatively weak.

To make the magnetic field more uniform over the sensing band, the windings are flat spirals. The number of turns per unit length increases from the center of the winding to the outer circumference. I have to let it happen. This also applies to each receiver coil winding and similar external Must be distributed in a diffused manner.

international search report AIIN S τ Fujie P = Attachment: α Buddha LS Shidanko Pressure Fugogolko 50% flGJ N), KT AtJ 88 0 22915 4375289 1) E 2732543 FR2398355GB 2001 250US 41i64376 MIIO! 11/83 E P 95467 +08301904

Claims (18)

[Claims] 1. Includes a transmitting coil and a receiving coil under the playing surface, and these two coils are connected to the playing surface. placed in a mutually adjacent arrangement under selected portions of the play court. Features: Ball position determination device. 2. The respective coils are arranged in an adjacent arrangement because they overlap. The position of the receiving coil is substantially zero relative to the transmitted magnetic field from the transmitting coil. 2. The pole position determination device according to claim 1, wherein 3. The receive coil has a shape that substantially self-phases the signals received from the far magnetic field source. Pole position according to claim 1 or 2, characterized in that it is adapted to perform killing. Judgment device. 4. Two receiving coils are arranged adjacent to the transmitting coil. A pole position determination device according to any one of claims 1 to 3. 5. The receiving coil has a first portion wound in a clockwise direction and a first portion wound in a counterclockwise direction. a second portion wound in the direction of the far field electromagnetic source. Claim 1, characterized in that it substantially self-cancels any signal received from the The ball position determining device according to any one of item 3. 6. Two receiving coils are arranged adjacent to the transmitting coil; The first one has a part wrapped in a clockwise direction and a part wrapped in a counterclockwise direction. The second receiving coil can be rotated clockwise or counterclockwise. between the two parts wound in either direction and the first part; a third part wound in the opposite circumferential direction than the two parts; and the boundary between the portions of the first coil is When viewed in the same plane as the boundary between any of the parts of the coil of The ball position determining device according to any one of claims 1 to 5, characterized in that: Place. 7. The transmitting coil is of elongated proportions and extends substantially below a line on the playing surface. and the receiving coil is in each case symmetrical with respect to the transmitting coil. and extending substantially the same dimensions and substantially coincident with the transmitting coil. The ball position determining device according to any one of claims 1 to 6, characterized in that: Place. 8. transmitting means adapted to generate an alternating electromagnetic signal coupled to said transmitting coil; a transmitting coil and a corresponding receiving coil; now detects signals regenerated by magnetic permeability in a near magnetic field close to both sides of the According to any one of claims 1 to 7, characterized in that a detection means is provided. pole position determination device. 9. The detection means detects a signal detected with respect to a signal transmitted by the transmitting coil. Any one of claims 1 to 8, characterized in that it includes means for performing synchronous demodulation of The pole position determination device described in one. 10. 5. The detector means includes a synchronous demodulator connected to a low pass filter. The pole position determining device according to any one of items 1 to 9. 11. The detector means further comprises processing means for determining pole position; Determine the ratio or comparison between the amplitudes of the signals received at each receiver coil circuit of each pair. Claim 1, which includes an algorithm including means for performing processing for determining The ball position determination device according to any one of Item 10. 12. The transmitted magnetic field is substantially sinusoidal, and the synchronous detector has a pole of It is selected to be in phase or quadrature with the magnetic permeability, and the synchronous detection The output device has a reactive to resistive ratio that is different from Paul's reactive to resistive ratio. including means for making a discrimination to reject false signals arising from substances having a ratio of A pole position determination device according to any one of claims 1 to 11. . 13. a microprocessor as part of said processing means; The sensor uses constraint parameters for determining and determining the apparent trajectory of the pole. Claims 1 to 12 include software algorithms that include data. The pole position determination device according to any one of the above. 14. Test whether the pole crosses near either end of either coil pair. making a determination to determine whether the issued and processed poll signal is indicative; A microprocessor containing software algorithms for each coil pair. a central microprocessor to which the processing data of the central microprocessor is transmitted; The processor selects data from all coil pairs that the pole has crossed nearby. or combined to produce a final determination of whether the pole was in or out. A pole position determination device according to claim 14, wherein the pole position determining device is configured as follows. 15. Each turn at the end of the receiving and transmitting coil circuit is widened and the widened The resulting windings are substantially spatially separated from a single strand of coil circuit. or each turn of said coil circuit is grouped together in more than one group. However, said groups are substantially spatially separated from each other and said spatial separation is The distance is that the sensitivity to the ball at the end of the court is near the center of the receiving coil pair. chosen not to be substantially higher than that of the corresponding pole position with respect to the line. The pole position according to any one of claims 1 to 14 defined Position determination device. 16. A metal screen is placed below said coil, and each winding of each coil is , is wound in a flat spiral shape, and the number of turns per unit length is from the center of each winding to The geometrical and conductor density increases from the outer periphery to the magnetic field. is selected so that it is reasonably uniform over the coil sensitivity zone. The pole position determining device according to any one of the first to fifteenth terms of the desired range. 17. Claim No. 1, which includes a tennis pole containing a substance that imparts substantial magnetic permeability. The pole position determining device according to any one of items 1 to 16. 18. Paul described and illustrated herein with respect to embodiments substantially as described above; Position determination device.