CA2104761A1 - Electronic device to improve a golf swing - Google Patents
Electronic device to improve a golf swingInfo
- Publication number
- CA2104761A1 CA2104761A1 CA 2104761 CA2104761A CA2104761A1 CA 2104761 A1 CA2104761 A1 CA 2104761A1 CA 2104761 CA2104761 CA 2104761 CA 2104761 A CA2104761 A CA 2104761A CA 2104761 A1 CA2104761 A1 CA 2104761A1
- Authority
- CA
- Canada
- Prior art keywords
- golf club
- value
- speed
- club head
- stored
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Landscapes
- Golf Clubs (AREA)
Abstract
ELECTRONIC DEVICE TO IMPROVE A GOLF SWING
ABSTRACT OF THE DISCLOSURE:
An apparatus to measure the speed of a golf club head during a detected golf club swing is provided. The intent is that, with practice, the user will have a consistent speed of swing, whereby the user may then be assured of a constant and predictable result from striking a golf ball with any golf club. The apparatus provides means for generating and receiving a radar signal, so that signals reflected from the golf club head when it is in a controlled path beforethe apparatus will be received, which signals are subjected to doppler shift. A
mixer is provided to determine the doppler shift, with the output being an audiosignal which is amplified. The resultant audio signal is analyzed to determine the period between any two consecutive similarly directed zero-crossings of the output signal, and upon application of algorithmic calculations and/or analysis which identifies specific signal characteristics and/or changes in specific signal characteristics, further signal processing of a binary stream indicative of the audio signal will be carried out to provide specific information as to the speedof the golf club head on any given swing being measured. Cumulative results may be stored whereby consistency of the swing may be determined, and club for distance or distance for club determinations may be made when a consistent swing has been established.
ABSTRACT OF THE DISCLOSURE:
An apparatus to measure the speed of a golf club head during a detected golf club swing is provided. The intent is that, with practice, the user will have a consistent speed of swing, whereby the user may then be assured of a constant and predictable result from striking a golf ball with any golf club. The apparatus provides means for generating and receiving a radar signal, so that signals reflected from the golf club head when it is in a controlled path beforethe apparatus will be received, which signals are subjected to doppler shift. A
mixer is provided to determine the doppler shift, with the output being an audiosignal which is amplified. The resultant audio signal is analyzed to determine the period between any two consecutive similarly directed zero-crossings of the output signal, and upon application of algorithmic calculations and/or analysis which identifies specific signal characteristics and/or changes in specific signal characteristics, further signal processing of a binary stream indicative of the audio signal will be carried out to provide specific information as to the speedof the golf club head on any given swing being measured. Cumulative results may be stored whereby consistency of the swing may be determined, and club for distance or distance for club determinations may be made when a consistent swing has been established.
Description
21047~1 ELECTRC)NIC DEVICE TO IMPROVE A GOLF SWING
FIELD OF THR INVENTION:
This invention relates to devices for improving golf club swings and more particularly to such devices that measure the speed of the golf club head during a portion of the swing.
Even more particularly, the present invention is directed to a device that uses radar to measure 5 the club head speed. Further, the device of the present invention can be used during an actual game of golf.
BACKGROUND OF THE ~NVENTION:
The game of golf is many centuries old and has changed very little during that time, at 10 least in terms of the fundamental object of the game and the mechanics and the physics of the physical aspect of the game. The game still uses a small relatively hard ball that is driven from a tee area towards and ultimately into a hole -- one of eighteen holes that make up a typical golf course. The distance from the tee to any given hole is considerable -- often from slightly less than 100 yards to a distance of in excess of 500 yards on some larger courses.
15 It can be seen that given the considerable distance that a ball must travel, theTe is a great deal of room for error in hitting the ball. The challenge Gf the game of golf is to drive the golf ball this great distance while still keeping the golf ball on its desired path, which is usually a relatively straight path. In order to do this, it is necessary to swing the golf club very quickly, although in a controlled and accurate manner, such that the head of the golf club will be 20 travelling at a high rate of speed when it impacts the golf ball. It is important that this speed be relatively maximized in order to drive the ball as far as possible, especially when driving the golf ball from the tee using a wood. Further, it is important that the speed of the club head be relatively consistent in order to produce a controlled golf shot It has been found that by maintaining a consistent swing of a golf club, a consistent shot results and fewer errors are 25 realized. A consistent swing, as such, implies that the speed of the golf club head is relatively constant from shot to shot.
210~76~
~ urther, it is desirable that a golfer's swing be consistent from club to club, at least as much as possible.
In order to drive a golf ball different distances, clubs of different lies are used, with the 5 lie being the angle of the face of the golf club head with respect to vertical. The clubs that are for driving a ball the farthest are the woods, which have a large wooden head and a shallow angle club face so that the ball is driven generally forwardly but only slightly in an upward direction. Clubs used for driving the ball medium or short distances have a smaller head, and are usually the irons. Each iron is configured so that the longer distance you wish to drive the 10 ball the longer the shaft of the iron is, and the more close to perpendicular the club face is angled at; and conversely, the shorter one wishes to drive the ball the shorter the club is, and the more severely angled the club face is. This allows for a reasonably consistent swing --consistent in terms of form and club head speed -- to be used to achieve different distances of driving the golf ball by allowing the mechanics and geometry of the club being used to 15 determine the distance that the ball will travel. Allowing a golfer to use a reasonably consistent swing to achieve different lengths of drives, except for fairly or very short hits, is highly advantageous in that once a golfer learns to swing properly it is relatively easy to hit the golf ball roughly a desired distance.
It has been found that in order to produce a proper and consistent golf swing --20 consistent in the terms of speed and also angle and height of the club head when it impacts theball -- it is ohen undesirable to swing as hard as possible, except possibly in the case of a v ery experienced golfer such as a professional. Most golfers produce a more consistent golf swing -- consistent in terms of using the same swing mechanics from one swing to the next as much as possible -- if they swing hard but not too hard It therefore follows that, in general, and at 25 least for each particular club that is used if not for all types of clubs, there is an optimum, or at least desired speed that the club head would reach as it impacts the ball, at least for any given golfer. If the club head is reaching a speed greater than the desired speed, then most likely the golfer is trying to swing too hard which will disturb the mechanics of the swing and resultingly the ball will probably not be hit in a straight and proper path, as desired. Further, 30 if the ball is hit at a lower speed then it is an indication that the golfer is doing one of two , . , ' - :' ~' '' . ~' ,' ' . : ~ ' 210~761 things. Firstly, the golfer may just be s-vinging more easily which may or may not be desirable. Secondly, the golfer may have perfonned the mechanics of the swing incorrectly thus resulting in an improper swing, which is of course undesirable. In any case, the speed of the club head as it impacts the ball is generally a fairly good indicator of whether a proper 5 swing was achieved, or it is at least a necessary component of a proper swing.Various devices have been developed to analyze a golfer's swing by recording andindicating various factors such as speed, angle, height and so on of a club head immediately before and immediately after impact with a golf ball. Generally speaking, most of these devices require a special practice hitting surface with sensors of some description within the 10 hitting surface or located on or at the practice area. In any event, this means that most prior art devices can only be used during practice sessions and cannot be used on a golf course, especially during an actual golf game. It would be highly beneficial to also be able to analyze one's golf swing during an actual golf game in addition to monitoring one's golf swing during practice, especially if it is monitored in the same manner during both actual play and practice 15 and the results indicated to the golfer are the same in each case, This provides a continuity in feedback between practice and actual games which cannot be accomplished by using the prior art devices presently available.
It is also obvious that it is desirable to be able to hit a golf ball as far as possible in order to reach the green in as few strokes as possible. Resultingly, all golfers endeavour to 2n improve their swing both in terms of proper mechanics and how hard the ball is hit. In order to learn to hit a ball harder it is useful to know how hard a ball has been hit and therefore how fast the golf head is moving at or near the ball impact zone.
It has been determined for experienced golfers who have learned the proper mechanics of a golf swing, that by concentrating on trying to improve the speed of the club head through 25 the ball impact zone, a better golf shot is usually accomplished, and the ball travels further.
PRIOR ART:
U.S. Patent 4,163,941 to LINN JR., discloses a Video Speed Analyzer of Golf ClubSwing or the Like, wherein a pair of colour television cameras are used to record the path of 30 a golf club swing. The velocity of the club head is subsequently calculated. This analyzer is 21~47~1 fairly complicated and apparently quite costly. Fu~ther, it could not realistically be used for analyzing a golf swing during actual play on a golf course.
U.S. Patent 4,304,406 to CROMARTY discloses a Golf Training and Practice Apparatus that employs infrared light sensors within a special platform to detect the swing of a golf club 5 head. The sensors allow for information to be recorded about the golf club head path, the face angle of the golf club head and also the relative weight on each of the golfers feet during various portions of the swing. The resulting information is displayed on a video screen. The Cromarty device does not appear to be concerned with measuring the speed of the club head;
however, it appears that it would be possible to provide such information from the calculated ]0 values generated and used by the device, with modification and adaptation to the device. Such a device could not be used in a real golf game situation.
U.S. Patent 4,306,722 to RUSNAK discloses a Golf Swing Training Apparatus that indicates the face angle of the club at impact with the ball. The golf club is provided with a light-reflective surface in order to accomplish this. Light is reflected off this surface and the 15 angle that the club face is oriented at will cause the light to be reflected to a different part of the sensor, thus allowing the club face angle to be determined. This means Ihat the golf club being used for training in association with the device is not generally a golf club that could be used in a real golf game situation.
U.S. Patent 4,146,230 to FOSTER discloses an Electronic Golf Club Trainer with Golf 20 Club Head Selection that discloses the speed of the golf club head, the distance the ball would have travelled depending on the club being used, whether the ball was impacted centrally or off-centre, and whether the club head struck the ball straight or at an angle. This device uses a strike mat having an array of photo switches underneath. Light is shone from a projector lamp above so that the shadow of the golf club head actuates the photo switches as it passes 25 over them. The time nt which the golf club head passes over each photo switch can be recorded. From these recorded times, the various parameters can be calculated. This device is meant only as a practice device, and obviously could not be used on a golf course in a real golf game situation.
.
-U.S. Patent 4,254,~56 to RUSNAK discloses a Golf Swing Training Apparatus that can indicate lateral club position and angular position of the club face and also speed of the club head, both before and after impact with a golf ball. A group of photo sensors or photo transistors are embedded within a base and are used to detect the shadow of a golf club head 5 immediately before and after it impacts a golf ball. The times at which the sensors are shadowed by the head of the golf club can be used to calculate the various parameters as necessary. As with other prior art devices described above, this device is not one which could be used in a real golf game situation.
U.S. Patent 4,542,906 to TAKASE et al discloses a Computer Aided Golf Training 10 Device for detecting movement of a golf ball and golf club head. Movement of the golf club head immediately before impact with the ball is detected by the deformation of a pair of fibre optic elements which transmit light from a light source to a pair of photo detectors. The golf club head slightly deforms the optical fibres, which causes a change in the light transmission characteristics thereof and resultingly changes the amount of light reaching the photo detectors.
15 The time between when the first optical fibre is deforrned and when the second optical fibre is deformed can be used to determine the club head speed. The path of the ball aftet it is hit is detetmined by an arrangement of lights and photo cells, which record the vertical portion of the path of the ball and also the time it takes the ball to travel between two points. From this, the initial speed of the ball can be calculated and subsequently an estimate of the path of 20 the ball can be calculated. Once again, this is not applicable to a real golf game situation.
U.S. Patent 4,451,043 to OGAWA e~ al discloses a Golf Trainer that senses a golf club swing and arithmetically calculates the velocity of the club head, the distance travelled by the ball and the offset angle of the face of the club head. There are three magnetic sensors buried in a protective mat. These magnetic sensors sense the presence of a club head as it passes over 25 the mat. The differences in the times that the club reaches each sensor are used to calculate the various outputs. This means that either special clubs must be used, or a very sensitive device that is subject to excessive outside disturbances -- which would result in false readings -- is used; and in any event, there is no relevance of the device to a real golf game situation.
Finally, U.S. Patent 4,630,829 to WHITE discloses a compact Golf Swing Training and Practice Device that uses a light supply and a plurality of light sensors, typically photo detectors, to sense the movement of a golf club head during a swing. A micro-processor is used to calculate the golf club head speed and the swing time of a golf stroke. The information may be displayed on a digital display or printed out on a printer. While this prior art device can be used without the aid of a practice mat, it can not realistically be used during a game of golf.
SUMMARY OF THE INVENTION:
The present invention provides an apparatus for measuring the speed of a golf club head during the bottom portion of a golf club swing, which is the area around the golf ball -- usually known as the impact zone -- by transmitting radar signals toward the area that the club head will pass through, receiving the reflected signals from the club head and measuring the doppler shift in the signals to calculate the speed of the club head. The speed of the club head can be displayed directly or can be displayed in other manners such as estimated distance travelled for the ball that is hit, percentage of a target club head speed, and so on.
8RIEF DESCRIPTI~N OF THE DRAVVINGS:
This invention is described hereafter with particular reference to the accompanying drawings, provided for illustration only but not so as to limit the invention described and its manner of operation, and in which:
Figure I is a block diagram schematic of the circuitry of the apparatus of the present invention;
Figure 2 is a representation of the manner of operation of the present invention; and Figure 3 shows a simplified but typical resultant audio signal utilized in the apparatus of the present invention for golf club head speed determination.
DETAILED DE~CRlPTlON OF THE PREFERRED EMBODIMENTS:
The apparatus of the present invtntion is to be used for measuring the club head speed of a golf club during a swing of the golf club. A consistent swing of a golf club is the key to hitting a golf ball properly, irrespective of the type of club used. A consistent swing for any 5 particular golfer is of relatively constant angular velocity -- at least through the impact zone -- and for any given club would have a consistent club head speed Longer golf clubs, such as the woods, or lower numbered irons, would have higher club head speeds than the shorter irons, for a given angular velocity club swing. Different distances of golf ball travel are achieved through this difference in golf club head speed and additionally through the face of 10 each type of golf club being of a particular lie In this manner, it is possible to use a consistent swing to hit a golf ball a variety of distances, from perhaps about 100 yards to about 250 yards for an average competent golfer In some circumstances, such as hitting a golf ball a distance below 100 yards, or in an extreme downhill or uphill lie, it may be that the swing speed will be slowed Such circumstances may particularly include approach shots to the green, and 15 finesse shots on the fairway or on approach to the green The apparatus of the present invention measures the speed of the club head and indicates the speed to the user The club head speed values can be stored for later viewing, and also a representative value (approximately the average value) of these stored speeds can be calculated and stored Further, the distance that a ball would travel given the golf club head 20 speed and also knowing the type of club used, such as a 1 wood driver, can be displayed The stored value for a swing speed can also be used to select a club for an approximate given distance In order to use the apparatus of the present invention to measure club head speed, the device is placed about two or three feet behind the area of the golf ball to be hit so that the 25 club does not make contact with the apparatus The apparatus emits radar signals toward the area of the golf ball These radar signals are interrupted by the head of a golf club during a swing, and are reflected back to the apparatus. Due to the reflection from the moving golf club the radar signals received by the apparatus are shifted in frequency, and are used to calculate the speed of the golf club head using known Doppler shift calculation algorithms 210~761 In use, the apparatus of the present invention can be used to measure the club head speed of any type of golf club. However, in order to store any results to be used in the calculation of distance for golf club selection, it is imperative that a I wood driver be used.
Distances that a golf ball would be hit by other clubs are calculated relative to the distance the ball would be hit by a 1 wood driver.
The apparatus of the present invention will now be discussed in detail with reference to Figure 1, which is a block circuit diagram. A radar freguency oscillator 20 generates a signal having a predetermined radar frequency, preferably in the "X" band, with the frequency being 10.525 GHz. The signal is fed from the radar frequency oscillator 20 to a radar transmitting antenna 22, which transmits radar signals at the predetermined radar frequency in a controlled path directed outwardly from the apparatus, toward the golf ball to be hit, when the apparatus is in use.
A radar receiving antenna 24 receives any radar signals that have been transmitted from the radar transmitter and subsequently reflected from the golf club head when the golf club head is in the controlled path, which of course occurs during a swing of the golf club.
A reflected signal received by the radar receiving antenna 24 is then fed to a second input port 30 of a mixer 26. The structure incorporating the radar receiving antenna 24, the mixer 26, the second input port 30 of the mixer 26, and an electrically conductive feedstrip 27, may conveniently be such as that disclosed in U.S. Patent 4t571,593 to Martinson, one of the present inventors. The mixer 26 also receives directly the predetermined radar frequency signal from the radar frequency oscillator 20 at its first input port 28. The mixer produces a signal that is the resultant audio frequency signal which is the resultant signal from the mixing of the signals received through the first input port 28 and the second input port 30.
The resultant audio frequency signal is output from the mixer at its output port 30 and is received by a high gain low noise audio amplifier means 32, which typically has a gain of between about 50 dB and about 80 dB. The audio amplifier means 32 has predetermined audio band pass characteristics such that there is a -3 dB point at about 1 K~lz and at about 5 KHz.
The audio amplifier means thus produces an audio signal output which is relatively flat in a predetermined audio frequency range between about 1 Kllz and about 5 KHz. Typically, the audio amplifier means 32 comprises an initial audio amplifier 34, a band pass filter 36 -- which ,;
may be a distributed filter having several discrete filter components at various places throughout an audio amplifier network --, and a final gain stage audio amplifier 38. Moreover, the audio amplifier is typically a high gain low noise amplifier, having a gain of 50 dB to B0 dB
The audio signal output from the audio amplifier means 32 is received by a comparator circuit means 40. The comparator circuit means 40 converts this output signal -- which is an oscillating wave form -- into a digital signal stream, wherein the digital signal stream is representative of the zero crossings of the output signal from the audio amplifier means 32.
The digital signal stream comprises a plurality of periods, with each period being between two consecutive similar edges that are representative of two consecutive similarly directed zero crossings of the output signal from the audio amplifier means.
The audio signal output from the audio amplifier means is also received by a trigger means 42 that uses this audio signal output to produce a trigger signal in response to a predetermined change in the signal characteristic of the audio signal output from the audio amplifier means 32. In the preferred embodiment, the trigger means 42 is a trigger circuit.
The trigger circuit includes an amplitude change detector that detects a predetermined change in the amplitude of the audio signal output from the audio amplifier means. When there is no golf club head moving through the controlled path of the transmitted radar signals, the amplitude of this audio signal output is very low with respect to a reference noise level. The presence of a moving golf club head in the controlled path will produce an audio signal output of approximately a known amplitude and the amplitude change detector can be set to detect a predetermined change in amplitude accordingly. When the amplitude change detector detects such a predetermined change in amplitude of the audio signal output, it produces a signal, which is fed into a second input 48 of a microprocessor means 44. The first input 46 of the microprocessor means 44 receives the digital signal stream from the comparator circuit means 40.
Applicant now refers to Figures 2 and 3 for an understanding of the signals that are being handled by the circllits of the present invention:
21~47~
Having regard to the discussion immediately above, it should be noted that, in general, the radar transmitting antenna 22 and the radar receiving antenna 24 are usually the same antenna, for compactness of the physical unit that embodies the present invention.
Accordingly, the physical unit is such that it may be carried in a pocket, or a small pouch in S the golf bag of the user. The unit weighs, at best, less than 400 grams including the battery.
Moreover, in keeping with usual mixer technology, the first and second input ports 28 and 30 to the mixer 26, from the RF oscillator 20 and the receiving antenna 24, respectively, are generally the same physical connection via the feedstrip 2~ to the mixer 26.
As shown in Figure 2, a physical golf speed measuring device 100 may be placed on the ground in the vicinity of the impact zone where a golf club will strike a golf ball. In the usual circumstances, a golf ball 102 is placed on a tee 104, although the golf ball 102 may be sitting on the ground such as the fairway being played on. The golfer usually addresses the ball 102 by setting his feet in the general vicinity beside the ball, and establishing his body, hands, and arms, and the position of the golf club, in a physical arrangement that is comfortable and will result in a consistent swing. Often times, the hands are slightly forward of the golf ball, or may be positioned beside it or behind it, depending on lhe golfer and the nature of the stroke to be made. In any event, it is usual for the golfer to establish his position with thP golf club 106 next to the golf ball 102, and then to withdraw the club slowly away from the ball before beginning his down swing when the club travels through the impact zone at a relatively high speed -- the speed which is to be determined by the apparatus of the present invention. Figure 2 represents the golf club 106 in a couple of positions during either the backswing or the downswing. The backswing is slow, and is suggested by arrow 108; whereas the downswing is fast and is suggested by arrow l l0.
As radar signals are transmitted from the device 100, they impact upon the golf club 106, if it is in the controlled path 112 of the signals being transmitted from the device 100.
The physical device is designed so that when it is placed on the ground behind the golf ball, the path 112 of transmission of the radar signals from the device is directed forwardly and slightly upwardly, so as to create a signal envelope in the area of the impact zone. The strength of the radar signal being transmitted from the receiver is very low, so that it will have been effectively dissipated only a few meters from the apparatus; but it is sufficiently strong 210~761 and the sensitivity of the receiving circuits of the apparatus is such that reflected signals from the golf club in the meter or so distance in front of the device which defines the impact zone will be received and discriminated by the device.
As noted, a resultant audio frequency signal comes from the output port of the mixer 5 as a consequence of the mixing of the radar frequency signal at the first input port -- a signal of constant frequency -- together with the reflected doppler signal received by the receiving antenna. Obviously, the frequency of the received signal exhibits a doppler shift, and the frequency of the received signal is a varying signal so that the period of each cycle of the received signal may differ slightly from the period of the preceding or following cycles.
Accordingly, it is possible to determine when the signals which demonstrate the golf club head speed through the impact zone are signals that are indicative of a real golf swing, and not a backswing or some other disturbance, by determining the frequency range within which such resultant audio signals are meaningful. For golf swings in the range of, say, above 55 mph up to, say, 125 mph, the resultant audio signal for X-band radiation at 10.525 GHz, 15 these values will typically be in the range of from about 1.7 KHz to about 4.0 KHz.
In any event, as noted in Figure 3, the present invention functions by determining the periods between consecutive similar edges of the resultant audio signal. Thus, for example, consecutive upwardly directed zero-crossings of the audio signal that is output from the audio amplifier may be determined; they are the zero-crossings indicated at 1, 2, 3, . . . N-l, N, and 20 N~l. Those zero-crossings define "N" periods, and each period has its own time span tl, t2, tN l, and tN.
Ultimately, the speed of the golf club head 106 as it passes through the impact zone will be determined by measurement of the '~" periods of the signal at output port 40 from the mixer 26. However, since the microprocessor is a digital device rather than an analog device, 25 it is clear that the output signal must first be converted into a digital signal stream, as noted above, so that the digital signal stream is thereby representative of each of the zero-crossings and the periods between them, where each period is thereby representative of two consecutive similarly directed zero-crossings of the output signal from the audio amplifier, as noted in Figure 3.
21047~1 "N" periods between "N+l" consecutive similar edges of the digital signal stream will be measured by the microprocessor. The value of each period is stored as a corresponding binary value in computer memory. Preferably, the number of periods measured and stored ("N") is greater than 20 and less than 120, usually in range of from 30 to 70. These binary S values may be initially stored in a second area of computer memory.
In any event, whether the binary values are initially stored in a second area of memory in microprocessor 44 as shown at 54, or they are directly fed to a first area of computer memory 52, it is clear that the stored binary value of each period relates to the speed of the head of the golf club 106 as it travels along the arc of travel 114 between any two points in 10 that arc. Information relating to the speed of the golf club head, which information is derived from the corresponding binary values of the periods of digital signal stream output from the comparator circuit 40, will be displayed at display means 46. The display means 46 may conveniently comprise a liquid crystal display, and in any event there may be displayed dynamic information which relates to the speed of the golf club head during a detected golf 15 club swing.
More conveniently, the differences between consecutive binary values are calculated and compared to a threshold value. If "Y" differences, which would be the number of differences between "Y+l" consecutive binary values, are each below a threshold value, then the binary values received subsequently in that second area of memory are transferred to a first area of 20 computer memory. Preferably, "Y" is in the range of from 3 to 10.
Generally, a filtering algorithm within the microprocessor 44 is used to derive a representative value from the stored '~" consecutive binary values. The representative value relates to the speed of the golf club head during the detected golf club swing. The filtering algorithm is similar to numerical averaging, but additionally will filter out any values that 25 appear to be not properly representative of the speed of the golf club head.
Once a representative value is calculated, it may be stored in a third area of computer memory indicated at 56. Indeed, the "M" most recently derived of the representative values are stored in temporally correct sequence in this third area 56 of computer memory, wherein "M" is a positive integer equal to or greater than 2. "M" is typically in the range of 7 to 14, 30 and the value of l0 is typically used.
,. .
The representative value relat~s to the speed of the golf club head during the swing, and may be a calculation of the actual speed of the golf club head, or in any event it is a numeric value related thereto. The speed value typically displayed in either miles per hour (mph) or kilometers per hour (kph).
As noted, the display of values is at display means 46. The "N" stored binary values are used to calculate information relating to the speed of the golf club head; and that information is typically the speed value, but alternatively it may be the approximate distance a typical golf ball would travel when struck by a golf club head moving at the speed represented by the representative value. The distance is typically expressed in yards. This approximate distance is determined by multiplying the representative value by a specific parameter, wherein the value of the specific parameter is dependent on the type of golf club used. The specific parameters range from 1.0 for a I wood driver to 0.60 for a pitching wedge golf club.
The "M" derived representative values stored in the third area 56 of computer memory may be used to selectively calculate a moving average golf club head speed value that is exemplary of a typical swing of a golf club. It is a "moving" average since the 10 most recent representative values are stored in the third area of computer memory. Further, the apparatus can selectively display the moving average golf club head speed and also store this moving average golf club head speed in a fourth area 58 of computer memory, for future display by the display means 46.
Still further, a certain form of "moving" average can be determined, which is referred to as a user-specific average speed value. This user-specific average speed value is determined in a similar manner to the "moving" average. The apparatus of the present invention can easily be adapted for use hy more than one user, and thus each "moving" average could be specifically stored as a user-specific average speed value for any given user.
` When a I wood driver is used, the moving average golf club head speed value to be stored may then be used for calculation of distance travelled by a golf ball. The basic reason for this is that the user-specific average speed of a I wood driver then gives a reference point for calculating the distances that other golf clubs would hit a golf ball. Specific parameters for such other clubs can be used to calculate the distance a golf ball would travel using any .
particular club, given a derived moving average golf club head speed value for a particular user-specific average speed.
Put in other words, when the given golf club to derive the user-specific average speed value is a I wood drivcr, then a weighted club parameter may be chosen for other clubs in 5 keeping with observed standards relating the distance a golf ball flies when struck by a 1 wood driver to the distance that the golf ball will travel when struck by any of the other clubs travelling essentially at the same speed. This provides a weighted club parameter for the other clubs, so that a determination of distance for any club, or club for any distance, may be made.
The determination of the correct club for any given distance is made by entering the 10 approximate distance into the apparatus. This approximate distance is entered into a fifth area 60 of computer memory, and the specific parameter and the moving average golf club head speed value may be used in comparison to the entered approximate distance value to determine the suggested club. The approximate distance entered into the fifth area of computer memory is chosen from a default set of values from 200 yards to 100 yards, in decrements of 10 yards.
15 For making that determination, the specific parameters for various clubs may, as noted above, range from 1.0 for a 1 wood driver to 0.60 for a pitching wedge.
In a further refinement of the triggering, whereby a trigger signal is issued only when the amplitude change detector detects a predetermined change in amplitude, there may be another condition established before the representative value which relates to the speed of the 20 golf club head is determined. That further condition can be that a determination of the representative value will only be made if more than one-half of the '~" consecutive binary values are within a specified range.
Of course, the present invention will also discriminate against backswings -- or even very low speed downswings. Thus, when the golfer makes his backswing, or for example a 25 slow speed downswing to confirm his set position as to the relative position of his hands and feet, and the club, with respect to the ball, it is desirable that no speed be registered or the moving average be recalculated. This is simply accomplished by first referring the digital data stream to a first go-nogo determination algorithm which will simply make a rough calculation as to the speed of the golf club head. If that speed is below a predetermined value -- say, 30 roughly about 35 mph -- then no further signal calculations will be made The apparatus then .~............ . .
210~761 returns to a rest mode and awaits a further digital signal stream which is indicative of the next swing of the golf club.
Finally, in an alternative embodiment of the present invention, there is a trigger means that is part of the microprocessor 44. In this case, the trigger means comprises means to deterrnine the absolute value of the difference between pairs of consecutive stored binary values of the "N" periods. The microprocessor compares the absolute values of the differences to a preset comparison value. A counter 62 is incremented if the absolute value of the difference is equal to or less than the preset comparison value. The counter is decremented if the absolute value of the difference is greater than the preset comparison value. When the counter reaches a predetermined number, with that predetermined number preferably being greater than or equal to 5, then the trigger means triggers the microprocessor 44 so as to use a filtering algorithm to derive a representative value from the stored "N" consecutive binary values.
When the triggering of the filter algorithm to derive the representative value from the stored "N" consecutive binary values occurs, then as described in detail above, the representative value will relate to the speed of the golf club head during the detected golf club swing. This means that the determination will not be made until the counter reaches a predetermined number, meaning that in any given sequence there must be considerably more increments made to the counter than decrements. Such conditions will only occur when the absolute value of the difference between any consecutive pair of stored binary values is within a very narrow range. That means that the apparatus of the present invention will, by these triggering means, eliminate spurious signals which may come, for example, as a consequence of setting the ball on a tee, or any motion related to determining the set position for the feet of the golfer, and so on.
Otherwise, the action of the apparatus in determining the speed of the golf club head, and the various conditions which must pre-exist before such deterrnination can be made, are as described above.
It should also be noted that the apparatus of the present invention can, with appropriate modifications as to expected speed values, and with appropriate mounting, be used for other sports implements. For example1 a baseball bat, or a tennis racquet or other racquet used for 210~7~1 court sports, may be swung through the controlled path of the radar signal transmitted from the apparatus. That means, however, that the apparatus will probably not be used in real game situations. However, it might be used in batting practice for a baseball player, or by a teaching professional teaching racquet sports, and so on. Thus, the apparatus of the present invention S is versatile. Moreover, because it is battery powered, has low power consumption, and is portable such as by being carried in the pocket, the speed measuring apparatus of the present invention may find nearly unlimited sports-related uses.
Thus, whereas the above discussion and the following claims are particularly directed to devices for measuring the speed of a golf club head, it is clear that without departing from 10 the spirit and scope of the claims otherwise, the device can be used for other sports-related purposes.
b:2082~19312082.193.~p~/Au8.23,931~m w:6446 . .
FIELD OF THR INVENTION:
This invention relates to devices for improving golf club swings and more particularly to such devices that measure the speed of the golf club head during a portion of the swing.
Even more particularly, the present invention is directed to a device that uses radar to measure 5 the club head speed. Further, the device of the present invention can be used during an actual game of golf.
BACKGROUND OF THE ~NVENTION:
The game of golf is many centuries old and has changed very little during that time, at 10 least in terms of the fundamental object of the game and the mechanics and the physics of the physical aspect of the game. The game still uses a small relatively hard ball that is driven from a tee area towards and ultimately into a hole -- one of eighteen holes that make up a typical golf course. The distance from the tee to any given hole is considerable -- often from slightly less than 100 yards to a distance of in excess of 500 yards on some larger courses.
15 It can be seen that given the considerable distance that a ball must travel, theTe is a great deal of room for error in hitting the ball. The challenge Gf the game of golf is to drive the golf ball this great distance while still keeping the golf ball on its desired path, which is usually a relatively straight path. In order to do this, it is necessary to swing the golf club very quickly, although in a controlled and accurate manner, such that the head of the golf club will be 20 travelling at a high rate of speed when it impacts the golf ball. It is important that this speed be relatively maximized in order to drive the ball as far as possible, especially when driving the golf ball from the tee using a wood. Further, it is important that the speed of the club head be relatively consistent in order to produce a controlled golf shot It has been found that by maintaining a consistent swing of a golf club, a consistent shot results and fewer errors are 25 realized. A consistent swing, as such, implies that the speed of the golf club head is relatively constant from shot to shot.
210~76~
~ urther, it is desirable that a golfer's swing be consistent from club to club, at least as much as possible.
In order to drive a golf ball different distances, clubs of different lies are used, with the 5 lie being the angle of the face of the golf club head with respect to vertical. The clubs that are for driving a ball the farthest are the woods, which have a large wooden head and a shallow angle club face so that the ball is driven generally forwardly but only slightly in an upward direction. Clubs used for driving the ball medium or short distances have a smaller head, and are usually the irons. Each iron is configured so that the longer distance you wish to drive the 10 ball the longer the shaft of the iron is, and the more close to perpendicular the club face is angled at; and conversely, the shorter one wishes to drive the ball the shorter the club is, and the more severely angled the club face is. This allows for a reasonably consistent swing --consistent in terms of form and club head speed -- to be used to achieve different distances of driving the golf ball by allowing the mechanics and geometry of the club being used to 15 determine the distance that the ball will travel. Allowing a golfer to use a reasonably consistent swing to achieve different lengths of drives, except for fairly or very short hits, is highly advantageous in that once a golfer learns to swing properly it is relatively easy to hit the golf ball roughly a desired distance.
It has been found that in order to produce a proper and consistent golf swing --20 consistent in the terms of speed and also angle and height of the club head when it impacts theball -- it is ohen undesirable to swing as hard as possible, except possibly in the case of a v ery experienced golfer such as a professional. Most golfers produce a more consistent golf swing -- consistent in terms of using the same swing mechanics from one swing to the next as much as possible -- if they swing hard but not too hard It therefore follows that, in general, and at 25 least for each particular club that is used if not for all types of clubs, there is an optimum, or at least desired speed that the club head would reach as it impacts the ball, at least for any given golfer. If the club head is reaching a speed greater than the desired speed, then most likely the golfer is trying to swing too hard which will disturb the mechanics of the swing and resultingly the ball will probably not be hit in a straight and proper path, as desired. Further, 30 if the ball is hit at a lower speed then it is an indication that the golfer is doing one of two , . , ' - :' ~' '' . ~' ,' ' . : ~ ' 210~761 things. Firstly, the golfer may just be s-vinging more easily which may or may not be desirable. Secondly, the golfer may have perfonned the mechanics of the swing incorrectly thus resulting in an improper swing, which is of course undesirable. In any case, the speed of the club head as it impacts the ball is generally a fairly good indicator of whether a proper 5 swing was achieved, or it is at least a necessary component of a proper swing.Various devices have been developed to analyze a golfer's swing by recording andindicating various factors such as speed, angle, height and so on of a club head immediately before and immediately after impact with a golf ball. Generally speaking, most of these devices require a special practice hitting surface with sensors of some description within the 10 hitting surface or located on or at the practice area. In any event, this means that most prior art devices can only be used during practice sessions and cannot be used on a golf course, especially during an actual golf game. It would be highly beneficial to also be able to analyze one's golf swing during an actual golf game in addition to monitoring one's golf swing during practice, especially if it is monitored in the same manner during both actual play and practice 15 and the results indicated to the golfer are the same in each case, This provides a continuity in feedback between practice and actual games which cannot be accomplished by using the prior art devices presently available.
It is also obvious that it is desirable to be able to hit a golf ball as far as possible in order to reach the green in as few strokes as possible. Resultingly, all golfers endeavour to 2n improve their swing both in terms of proper mechanics and how hard the ball is hit. In order to learn to hit a ball harder it is useful to know how hard a ball has been hit and therefore how fast the golf head is moving at or near the ball impact zone.
It has been determined for experienced golfers who have learned the proper mechanics of a golf swing, that by concentrating on trying to improve the speed of the club head through 25 the ball impact zone, a better golf shot is usually accomplished, and the ball travels further.
PRIOR ART:
U.S. Patent 4,163,941 to LINN JR., discloses a Video Speed Analyzer of Golf ClubSwing or the Like, wherein a pair of colour television cameras are used to record the path of 30 a golf club swing. The velocity of the club head is subsequently calculated. This analyzer is 21~47~1 fairly complicated and apparently quite costly. Fu~ther, it could not realistically be used for analyzing a golf swing during actual play on a golf course.
U.S. Patent 4,304,406 to CROMARTY discloses a Golf Training and Practice Apparatus that employs infrared light sensors within a special platform to detect the swing of a golf club 5 head. The sensors allow for information to be recorded about the golf club head path, the face angle of the golf club head and also the relative weight on each of the golfers feet during various portions of the swing. The resulting information is displayed on a video screen. The Cromarty device does not appear to be concerned with measuring the speed of the club head;
however, it appears that it would be possible to provide such information from the calculated ]0 values generated and used by the device, with modification and adaptation to the device. Such a device could not be used in a real golf game situation.
U.S. Patent 4,306,722 to RUSNAK discloses a Golf Swing Training Apparatus that indicates the face angle of the club at impact with the ball. The golf club is provided with a light-reflective surface in order to accomplish this. Light is reflected off this surface and the 15 angle that the club face is oriented at will cause the light to be reflected to a different part of the sensor, thus allowing the club face angle to be determined. This means Ihat the golf club being used for training in association with the device is not generally a golf club that could be used in a real golf game situation.
U.S. Patent 4,146,230 to FOSTER discloses an Electronic Golf Club Trainer with Golf 20 Club Head Selection that discloses the speed of the golf club head, the distance the ball would have travelled depending on the club being used, whether the ball was impacted centrally or off-centre, and whether the club head struck the ball straight or at an angle. This device uses a strike mat having an array of photo switches underneath. Light is shone from a projector lamp above so that the shadow of the golf club head actuates the photo switches as it passes 25 over them. The time nt which the golf club head passes over each photo switch can be recorded. From these recorded times, the various parameters can be calculated. This device is meant only as a practice device, and obviously could not be used on a golf course in a real golf game situation.
.
-U.S. Patent 4,254,~56 to RUSNAK discloses a Golf Swing Training Apparatus that can indicate lateral club position and angular position of the club face and also speed of the club head, both before and after impact with a golf ball. A group of photo sensors or photo transistors are embedded within a base and are used to detect the shadow of a golf club head 5 immediately before and after it impacts a golf ball. The times at which the sensors are shadowed by the head of the golf club can be used to calculate the various parameters as necessary. As with other prior art devices described above, this device is not one which could be used in a real golf game situation.
U.S. Patent 4,542,906 to TAKASE et al discloses a Computer Aided Golf Training 10 Device for detecting movement of a golf ball and golf club head. Movement of the golf club head immediately before impact with the ball is detected by the deformation of a pair of fibre optic elements which transmit light from a light source to a pair of photo detectors. The golf club head slightly deforms the optical fibres, which causes a change in the light transmission characteristics thereof and resultingly changes the amount of light reaching the photo detectors.
15 The time between when the first optical fibre is deforrned and when the second optical fibre is deformed can be used to determine the club head speed. The path of the ball aftet it is hit is detetmined by an arrangement of lights and photo cells, which record the vertical portion of the path of the ball and also the time it takes the ball to travel between two points. From this, the initial speed of the ball can be calculated and subsequently an estimate of the path of 20 the ball can be calculated. Once again, this is not applicable to a real golf game situation.
U.S. Patent 4,451,043 to OGAWA e~ al discloses a Golf Trainer that senses a golf club swing and arithmetically calculates the velocity of the club head, the distance travelled by the ball and the offset angle of the face of the club head. There are three magnetic sensors buried in a protective mat. These magnetic sensors sense the presence of a club head as it passes over 25 the mat. The differences in the times that the club reaches each sensor are used to calculate the various outputs. This means that either special clubs must be used, or a very sensitive device that is subject to excessive outside disturbances -- which would result in false readings -- is used; and in any event, there is no relevance of the device to a real golf game situation.
Finally, U.S. Patent 4,630,829 to WHITE discloses a compact Golf Swing Training and Practice Device that uses a light supply and a plurality of light sensors, typically photo detectors, to sense the movement of a golf club head during a swing. A micro-processor is used to calculate the golf club head speed and the swing time of a golf stroke. The information may be displayed on a digital display or printed out on a printer. While this prior art device can be used without the aid of a practice mat, it can not realistically be used during a game of golf.
SUMMARY OF THE INVENTION:
The present invention provides an apparatus for measuring the speed of a golf club head during the bottom portion of a golf club swing, which is the area around the golf ball -- usually known as the impact zone -- by transmitting radar signals toward the area that the club head will pass through, receiving the reflected signals from the club head and measuring the doppler shift in the signals to calculate the speed of the club head. The speed of the club head can be displayed directly or can be displayed in other manners such as estimated distance travelled for the ball that is hit, percentage of a target club head speed, and so on.
8RIEF DESCRIPTI~N OF THE DRAVVINGS:
This invention is described hereafter with particular reference to the accompanying drawings, provided for illustration only but not so as to limit the invention described and its manner of operation, and in which:
Figure I is a block diagram schematic of the circuitry of the apparatus of the present invention;
Figure 2 is a representation of the manner of operation of the present invention; and Figure 3 shows a simplified but typical resultant audio signal utilized in the apparatus of the present invention for golf club head speed determination.
DETAILED DE~CRlPTlON OF THE PREFERRED EMBODIMENTS:
The apparatus of the present invtntion is to be used for measuring the club head speed of a golf club during a swing of the golf club. A consistent swing of a golf club is the key to hitting a golf ball properly, irrespective of the type of club used. A consistent swing for any 5 particular golfer is of relatively constant angular velocity -- at least through the impact zone -- and for any given club would have a consistent club head speed Longer golf clubs, such as the woods, or lower numbered irons, would have higher club head speeds than the shorter irons, for a given angular velocity club swing. Different distances of golf ball travel are achieved through this difference in golf club head speed and additionally through the face of 10 each type of golf club being of a particular lie In this manner, it is possible to use a consistent swing to hit a golf ball a variety of distances, from perhaps about 100 yards to about 250 yards for an average competent golfer In some circumstances, such as hitting a golf ball a distance below 100 yards, or in an extreme downhill or uphill lie, it may be that the swing speed will be slowed Such circumstances may particularly include approach shots to the green, and 15 finesse shots on the fairway or on approach to the green The apparatus of the present invention measures the speed of the club head and indicates the speed to the user The club head speed values can be stored for later viewing, and also a representative value (approximately the average value) of these stored speeds can be calculated and stored Further, the distance that a ball would travel given the golf club head 20 speed and also knowing the type of club used, such as a 1 wood driver, can be displayed The stored value for a swing speed can also be used to select a club for an approximate given distance In order to use the apparatus of the present invention to measure club head speed, the device is placed about two or three feet behind the area of the golf ball to be hit so that the 25 club does not make contact with the apparatus The apparatus emits radar signals toward the area of the golf ball These radar signals are interrupted by the head of a golf club during a swing, and are reflected back to the apparatus. Due to the reflection from the moving golf club the radar signals received by the apparatus are shifted in frequency, and are used to calculate the speed of the golf club head using known Doppler shift calculation algorithms 210~761 In use, the apparatus of the present invention can be used to measure the club head speed of any type of golf club. However, in order to store any results to be used in the calculation of distance for golf club selection, it is imperative that a I wood driver be used.
Distances that a golf ball would be hit by other clubs are calculated relative to the distance the ball would be hit by a 1 wood driver.
The apparatus of the present invention will now be discussed in detail with reference to Figure 1, which is a block circuit diagram. A radar freguency oscillator 20 generates a signal having a predetermined radar frequency, preferably in the "X" band, with the frequency being 10.525 GHz. The signal is fed from the radar frequency oscillator 20 to a radar transmitting antenna 22, which transmits radar signals at the predetermined radar frequency in a controlled path directed outwardly from the apparatus, toward the golf ball to be hit, when the apparatus is in use.
A radar receiving antenna 24 receives any radar signals that have been transmitted from the radar transmitter and subsequently reflected from the golf club head when the golf club head is in the controlled path, which of course occurs during a swing of the golf club.
A reflected signal received by the radar receiving antenna 24 is then fed to a second input port 30 of a mixer 26. The structure incorporating the radar receiving antenna 24, the mixer 26, the second input port 30 of the mixer 26, and an electrically conductive feedstrip 27, may conveniently be such as that disclosed in U.S. Patent 4t571,593 to Martinson, one of the present inventors. The mixer 26 also receives directly the predetermined radar frequency signal from the radar frequency oscillator 20 at its first input port 28. The mixer produces a signal that is the resultant audio frequency signal which is the resultant signal from the mixing of the signals received through the first input port 28 and the second input port 30.
The resultant audio frequency signal is output from the mixer at its output port 30 and is received by a high gain low noise audio amplifier means 32, which typically has a gain of between about 50 dB and about 80 dB. The audio amplifier means 32 has predetermined audio band pass characteristics such that there is a -3 dB point at about 1 K~lz and at about 5 KHz.
The audio amplifier means thus produces an audio signal output which is relatively flat in a predetermined audio frequency range between about 1 Kllz and about 5 KHz. Typically, the audio amplifier means 32 comprises an initial audio amplifier 34, a band pass filter 36 -- which ,;
may be a distributed filter having several discrete filter components at various places throughout an audio amplifier network --, and a final gain stage audio amplifier 38. Moreover, the audio amplifier is typically a high gain low noise amplifier, having a gain of 50 dB to B0 dB
The audio signal output from the audio amplifier means 32 is received by a comparator circuit means 40. The comparator circuit means 40 converts this output signal -- which is an oscillating wave form -- into a digital signal stream, wherein the digital signal stream is representative of the zero crossings of the output signal from the audio amplifier means 32.
The digital signal stream comprises a plurality of periods, with each period being between two consecutive similar edges that are representative of two consecutive similarly directed zero crossings of the output signal from the audio amplifier means.
The audio signal output from the audio amplifier means is also received by a trigger means 42 that uses this audio signal output to produce a trigger signal in response to a predetermined change in the signal characteristic of the audio signal output from the audio amplifier means 32. In the preferred embodiment, the trigger means 42 is a trigger circuit.
The trigger circuit includes an amplitude change detector that detects a predetermined change in the amplitude of the audio signal output from the audio amplifier means. When there is no golf club head moving through the controlled path of the transmitted radar signals, the amplitude of this audio signal output is very low with respect to a reference noise level. The presence of a moving golf club head in the controlled path will produce an audio signal output of approximately a known amplitude and the amplitude change detector can be set to detect a predetermined change in amplitude accordingly. When the amplitude change detector detects such a predetermined change in amplitude of the audio signal output, it produces a signal, which is fed into a second input 48 of a microprocessor means 44. The first input 46 of the microprocessor means 44 receives the digital signal stream from the comparator circuit means 40.
Applicant now refers to Figures 2 and 3 for an understanding of the signals that are being handled by the circllits of the present invention:
21~47~
Having regard to the discussion immediately above, it should be noted that, in general, the radar transmitting antenna 22 and the radar receiving antenna 24 are usually the same antenna, for compactness of the physical unit that embodies the present invention.
Accordingly, the physical unit is such that it may be carried in a pocket, or a small pouch in S the golf bag of the user. The unit weighs, at best, less than 400 grams including the battery.
Moreover, in keeping with usual mixer technology, the first and second input ports 28 and 30 to the mixer 26, from the RF oscillator 20 and the receiving antenna 24, respectively, are generally the same physical connection via the feedstrip 2~ to the mixer 26.
As shown in Figure 2, a physical golf speed measuring device 100 may be placed on the ground in the vicinity of the impact zone where a golf club will strike a golf ball. In the usual circumstances, a golf ball 102 is placed on a tee 104, although the golf ball 102 may be sitting on the ground such as the fairway being played on. The golfer usually addresses the ball 102 by setting his feet in the general vicinity beside the ball, and establishing his body, hands, and arms, and the position of the golf club, in a physical arrangement that is comfortable and will result in a consistent swing. Often times, the hands are slightly forward of the golf ball, or may be positioned beside it or behind it, depending on lhe golfer and the nature of the stroke to be made. In any event, it is usual for the golfer to establish his position with thP golf club 106 next to the golf ball 102, and then to withdraw the club slowly away from the ball before beginning his down swing when the club travels through the impact zone at a relatively high speed -- the speed which is to be determined by the apparatus of the present invention. Figure 2 represents the golf club 106 in a couple of positions during either the backswing or the downswing. The backswing is slow, and is suggested by arrow 108; whereas the downswing is fast and is suggested by arrow l l0.
As radar signals are transmitted from the device 100, they impact upon the golf club 106, if it is in the controlled path 112 of the signals being transmitted from the device 100.
The physical device is designed so that when it is placed on the ground behind the golf ball, the path 112 of transmission of the radar signals from the device is directed forwardly and slightly upwardly, so as to create a signal envelope in the area of the impact zone. The strength of the radar signal being transmitted from the receiver is very low, so that it will have been effectively dissipated only a few meters from the apparatus; but it is sufficiently strong 210~761 and the sensitivity of the receiving circuits of the apparatus is such that reflected signals from the golf club in the meter or so distance in front of the device which defines the impact zone will be received and discriminated by the device.
As noted, a resultant audio frequency signal comes from the output port of the mixer 5 as a consequence of the mixing of the radar frequency signal at the first input port -- a signal of constant frequency -- together with the reflected doppler signal received by the receiving antenna. Obviously, the frequency of the received signal exhibits a doppler shift, and the frequency of the received signal is a varying signal so that the period of each cycle of the received signal may differ slightly from the period of the preceding or following cycles.
Accordingly, it is possible to determine when the signals which demonstrate the golf club head speed through the impact zone are signals that are indicative of a real golf swing, and not a backswing or some other disturbance, by determining the frequency range within which such resultant audio signals are meaningful. For golf swings in the range of, say, above 55 mph up to, say, 125 mph, the resultant audio signal for X-band radiation at 10.525 GHz, 15 these values will typically be in the range of from about 1.7 KHz to about 4.0 KHz.
In any event, as noted in Figure 3, the present invention functions by determining the periods between consecutive similar edges of the resultant audio signal. Thus, for example, consecutive upwardly directed zero-crossings of the audio signal that is output from the audio amplifier may be determined; they are the zero-crossings indicated at 1, 2, 3, . . . N-l, N, and 20 N~l. Those zero-crossings define "N" periods, and each period has its own time span tl, t2, tN l, and tN.
Ultimately, the speed of the golf club head 106 as it passes through the impact zone will be determined by measurement of the '~" periods of the signal at output port 40 from the mixer 26. However, since the microprocessor is a digital device rather than an analog device, 25 it is clear that the output signal must first be converted into a digital signal stream, as noted above, so that the digital signal stream is thereby representative of each of the zero-crossings and the periods between them, where each period is thereby representative of two consecutive similarly directed zero-crossings of the output signal from the audio amplifier, as noted in Figure 3.
21047~1 "N" periods between "N+l" consecutive similar edges of the digital signal stream will be measured by the microprocessor. The value of each period is stored as a corresponding binary value in computer memory. Preferably, the number of periods measured and stored ("N") is greater than 20 and less than 120, usually in range of from 30 to 70. These binary S values may be initially stored in a second area of computer memory.
In any event, whether the binary values are initially stored in a second area of memory in microprocessor 44 as shown at 54, or they are directly fed to a first area of computer memory 52, it is clear that the stored binary value of each period relates to the speed of the head of the golf club 106 as it travels along the arc of travel 114 between any two points in 10 that arc. Information relating to the speed of the golf club head, which information is derived from the corresponding binary values of the periods of digital signal stream output from the comparator circuit 40, will be displayed at display means 46. The display means 46 may conveniently comprise a liquid crystal display, and in any event there may be displayed dynamic information which relates to the speed of the golf club head during a detected golf 15 club swing.
More conveniently, the differences between consecutive binary values are calculated and compared to a threshold value. If "Y" differences, which would be the number of differences between "Y+l" consecutive binary values, are each below a threshold value, then the binary values received subsequently in that second area of memory are transferred to a first area of 20 computer memory. Preferably, "Y" is in the range of from 3 to 10.
Generally, a filtering algorithm within the microprocessor 44 is used to derive a representative value from the stored '~" consecutive binary values. The representative value relates to the speed of the golf club head during the detected golf club swing. The filtering algorithm is similar to numerical averaging, but additionally will filter out any values that 25 appear to be not properly representative of the speed of the golf club head.
Once a representative value is calculated, it may be stored in a third area of computer memory indicated at 56. Indeed, the "M" most recently derived of the representative values are stored in temporally correct sequence in this third area 56 of computer memory, wherein "M" is a positive integer equal to or greater than 2. "M" is typically in the range of 7 to 14, 30 and the value of l0 is typically used.
,. .
The representative value relat~s to the speed of the golf club head during the swing, and may be a calculation of the actual speed of the golf club head, or in any event it is a numeric value related thereto. The speed value typically displayed in either miles per hour (mph) or kilometers per hour (kph).
As noted, the display of values is at display means 46. The "N" stored binary values are used to calculate information relating to the speed of the golf club head; and that information is typically the speed value, but alternatively it may be the approximate distance a typical golf ball would travel when struck by a golf club head moving at the speed represented by the representative value. The distance is typically expressed in yards. This approximate distance is determined by multiplying the representative value by a specific parameter, wherein the value of the specific parameter is dependent on the type of golf club used. The specific parameters range from 1.0 for a I wood driver to 0.60 for a pitching wedge golf club.
The "M" derived representative values stored in the third area 56 of computer memory may be used to selectively calculate a moving average golf club head speed value that is exemplary of a typical swing of a golf club. It is a "moving" average since the 10 most recent representative values are stored in the third area of computer memory. Further, the apparatus can selectively display the moving average golf club head speed and also store this moving average golf club head speed in a fourth area 58 of computer memory, for future display by the display means 46.
Still further, a certain form of "moving" average can be determined, which is referred to as a user-specific average speed value. This user-specific average speed value is determined in a similar manner to the "moving" average. The apparatus of the present invention can easily be adapted for use hy more than one user, and thus each "moving" average could be specifically stored as a user-specific average speed value for any given user.
` When a I wood driver is used, the moving average golf club head speed value to be stored may then be used for calculation of distance travelled by a golf ball. The basic reason for this is that the user-specific average speed of a I wood driver then gives a reference point for calculating the distances that other golf clubs would hit a golf ball. Specific parameters for such other clubs can be used to calculate the distance a golf ball would travel using any .
particular club, given a derived moving average golf club head speed value for a particular user-specific average speed.
Put in other words, when the given golf club to derive the user-specific average speed value is a I wood drivcr, then a weighted club parameter may be chosen for other clubs in 5 keeping with observed standards relating the distance a golf ball flies when struck by a 1 wood driver to the distance that the golf ball will travel when struck by any of the other clubs travelling essentially at the same speed. This provides a weighted club parameter for the other clubs, so that a determination of distance for any club, or club for any distance, may be made.
The determination of the correct club for any given distance is made by entering the 10 approximate distance into the apparatus. This approximate distance is entered into a fifth area 60 of computer memory, and the specific parameter and the moving average golf club head speed value may be used in comparison to the entered approximate distance value to determine the suggested club. The approximate distance entered into the fifth area of computer memory is chosen from a default set of values from 200 yards to 100 yards, in decrements of 10 yards.
15 For making that determination, the specific parameters for various clubs may, as noted above, range from 1.0 for a 1 wood driver to 0.60 for a pitching wedge.
In a further refinement of the triggering, whereby a trigger signal is issued only when the amplitude change detector detects a predetermined change in amplitude, there may be another condition established before the representative value which relates to the speed of the 20 golf club head is determined. That further condition can be that a determination of the representative value will only be made if more than one-half of the '~" consecutive binary values are within a specified range.
Of course, the present invention will also discriminate against backswings -- or even very low speed downswings. Thus, when the golfer makes his backswing, or for example a 25 slow speed downswing to confirm his set position as to the relative position of his hands and feet, and the club, with respect to the ball, it is desirable that no speed be registered or the moving average be recalculated. This is simply accomplished by first referring the digital data stream to a first go-nogo determination algorithm which will simply make a rough calculation as to the speed of the golf club head. If that speed is below a predetermined value -- say, 30 roughly about 35 mph -- then no further signal calculations will be made The apparatus then .~............ . .
210~761 returns to a rest mode and awaits a further digital signal stream which is indicative of the next swing of the golf club.
Finally, in an alternative embodiment of the present invention, there is a trigger means that is part of the microprocessor 44. In this case, the trigger means comprises means to deterrnine the absolute value of the difference between pairs of consecutive stored binary values of the "N" periods. The microprocessor compares the absolute values of the differences to a preset comparison value. A counter 62 is incremented if the absolute value of the difference is equal to or less than the preset comparison value. The counter is decremented if the absolute value of the difference is greater than the preset comparison value. When the counter reaches a predetermined number, with that predetermined number preferably being greater than or equal to 5, then the trigger means triggers the microprocessor 44 so as to use a filtering algorithm to derive a representative value from the stored "N" consecutive binary values.
When the triggering of the filter algorithm to derive the representative value from the stored "N" consecutive binary values occurs, then as described in detail above, the representative value will relate to the speed of the golf club head during the detected golf club swing. This means that the determination will not be made until the counter reaches a predetermined number, meaning that in any given sequence there must be considerably more increments made to the counter than decrements. Such conditions will only occur when the absolute value of the difference between any consecutive pair of stored binary values is within a very narrow range. That means that the apparatus of the present invention will, by these triggering means, eliminate spurious signals which may come, for example, as a consequence of setting the ball on a tee, or any motion related to determining the set position for the feet of the golfer, and so on.
Otherwise, the action of the apparatus in determining the speed of the golf club head, and the various conditions which must pre-exist before such deterrnination can be made, are as described above.
It should also be noted that the apparatus of the present invention can, with appropriate modifications as to expected speed values, and with appropriate mounting, be used for other sports implements. For example1 a baseball bat, or a tennis racquet or other racquet used for 210~7~1 court sports, may be swung through the controlled path of the radar signal transmitted from the apparatus. That means, however, that the apparatus will probably not be used in real game situations. However, it might be used in batting practice for a baseball player, or by a teaching professional teaching racquet sports, and so on. Thus, the apparatus of the present invention S is versatile. Moreover, because it is battery powered, has low power consumption, and is portable such as by being carried in the pocket, the speed measuring apparatus of the present invention may find nearly unlimited sports-related uses.
Thus, whereas the above discussion and the following claims are particularly directed to devices for measuring the speed of a golf club head, it is clear that without departing from 10 the spirit and scope of the claims otherwise, the device can be used for other sports-related purposes.
b:2082~19312082.193.~p~/Au8.23,931~m w:6446 . .
Claims (48)
1. An apparatus for measuring the speed of a golf club head during a detected golf club swing, comprising:
a radar frequency oscillator that generates a signal having a predetermined radar frequency;
a radar transmitting antenna;
a radar signal transmitter that transmits radar signals at said predetermined radar frequency in a controlled path directed outwardly from said apparatus;
a radar receiving antenna for receiving radar signals that have been transmittedfrom said radar signal transmitter and subsequently reflected from said golf club head when in said controlled path;
a mixer having first and second input ports and an output port, wherein said first input port receives a signal having said predetermined frequency from said oscillator, wherein said second input port is a radar signal input that receives said reflected radar signals, and wherein the signal from said mixer output port is the resultant audio frequency signal from the mixing of the signals delivered to said mixer at said first and second input ports thereof;
means to feed a signal from said radar receiving antenna to said radar signal input port of said mixer;
audio amplifier means having predetermined audio band pass characteristics connected to the output port of said mixer, wherein said audio amplifier means has an audio signal output in a predetermined audio frequency range;
comparator circuit means for converting the output signal from said audio amplifier means into a digital signal stream, wherein said digital signal stream is representative of zero-crossings of said output signal from said audio amplifier means and wherein said digital signal stream comprises a plurality of periods, each period being between two consecutive similar edges that are representative of two consecutive similarly directed zero-crossings of said output signal from said audio amplifier means;
trigger means that produces a trigger signal in response to a predetermined change in signal characteristic of said audio amplifier output signal;
microprocessor means having a first input, wherein said first input receives said digital signal stream from said comparator circuit;
wherein the "N" periods between "N+1" consecutive similar edges of said digital signal stream are measured by said microprocessor and the value of each period is stored as a corresponding binary value in a first area of computer memory, and wherein each of said stored binary values relates to the speed of the head of the golf club along its arc of travel between two points in that arc; and display means wherein said "N" stored binary values are used to calculate a display value relating to the speed of the golf club head during said detected golf club swing to a user of said apparatus.
a radar frequency oscillator that generates a signal having a predetermined radar frequency;
a radar transmitting antenna;
a radar signal transmitter that transmits radar signals at said predetermined radar frequency in a controlled path directed outwardly from said apparatus;
a radar receiving antenna for receiving radar signals that have been transmittedfrom said radar signal transmitter and subsequently reflected from said golf club head when in said controlled path;
a mixer having first and second input ports and an output port, wherein said first input port receives a signal having said predetermined frequency from said oscillator, wherein said second input port is a radar signal input that receives said reflected radar signals, and wherein the signal from said mixer output port is the resultant audio frequency signal from the mixing of the signals delivered to said mixer at said first and second input ports thereof;
means to feed a signal from said radar receiving antenna to said radar signal input port of said mixer;
audio amplifier means having predetermined audio band pass characteristics connected to the output port of said mixer, wherein said audio amplifier means has an audio signal output in a predetermined audio frequency range;
comparator circuit means for converting the output signal from said audio amplifier means into a digital signal stream, wherein said digital signal stream is representative of zero-crossings of said output signal from said audio amplifier means and wherein said digital signal stream comprises a plurality of periods, each period being between two consecutive similar edges that are representative of two consecutive similarly directed zero-crossings of said output signal from said audio amplifier means;
trigger means that produces a trigger signal in response to a predetermined change in signal characteristic of said audio amplifier output signal;
microprocessor means having a first input, wherein said first input receives said digital signal stream from said comparator circuit;
wherein the "N" periods between "N+1" consecutive similar edges of said digital signal stream are measured by said microprocessor and the value of each period is stored as a corresponding binary value in a first area of computer memory, and wherein each of said stored binary values relates to the speed of the head of the golf club along its arc of travel between two points in that arc; and display means wherein said "N" stored binary values are used to calculate a display value relating to the speed of the golf club head during said detected golf club swing to a user of said apparatus.
2. The apparatus of claim 1, wherein said radar transmitting antenna and said radar receiving antenna are a single antenna.
3, The apparatus of claim 2, wherein said first and second mixer input ports are the same input port.
4. The apparatus of claim 2, wherein said trigger means is a trigger circuit.
5. The apparatus of claim 4, wherein said microprocessor means has a second input;
wherein said trigger circuit includes an amplitude change detector that detects a predetermined change in amplitude of said audio signal output from said audio amplifier, wherein said trigger circuit produces a trigger signal when said amplitude change detector detects said predetermined change in amplitude, which trigger signal is fed to said second input of said microprocessor; and wherein, when said trigger signal is produced, storage of said "N"
consecutive binary values begins and said microprocessor uses a filtering algorithm to derive a representative value from said stored "N" consecutive binary values, which representative value relates to the speed of said golf club head during said detected golf club swing.
wherein said trigger circuit includes an amplitude change detector that detects a predetermined change in amplitude of said audio signal output from said audio amplifier, wherein said trigger circuit produces a trigger signal when said amplitude change detector detects said predetermined change in amplitude, which trigger signal is fed to said second input of said microprocessor; and wherein, when said trigger signal is produced, storage of said "N"
consecutive binary values begins and said microprocessor uses a filtering algorithm to derive a representative value from said stored "N" consecutive binary values, which representative value relates to the speed of said golf club head during said detected golf club swing.
6. The apparatus of claim 5, wherein said apparatus uses said representative value to calculate a speed value of the speed of the golf club head, and wherein said display means displays said speed value.
7. The apparatus of claim 1, wherein the number of periods measured and stored is greater than 20.
8. The apparatus of claim 3, wherein the number of periods measured and stored is in the range of from 20 to 120.
9. The apparatus of claim 5, wherein the number of periods measured and stored is in the range of from 30 to 70.
10. The apparatus of claim 9, wherein the periods between consecutive similar edges of said digital signal stream are measured by said microprocessor and initially stored as binary values in a second area of computer memory, and wherein when each of the Y differences between Y + 1 consecutive binary values is below a threshold amount, said binary values are transferred to said first area of memory.
11, The apparatus of claim 10, wherein Y is in the range of from 3 to 10.
12. The apparatus of claim 5, wherein said representative value may be stored in a third area of computer memory.
13. The apparatus of claim 12, wherein the "M" most recently derived of said representative values are stored in temporally correct sequence in said third area of computer memory, and wherein "M" is a positive integer equal to or greater than 2.
14. The apparatus of claim 13, wherein "M" is in the range of 7 to 14.
15. The apparatus of claim 13, wherein said "M" derived representative values stored in said third area of computer memory are used to selectively calculate a moving average golf club head speed value that is exemplary of a typical swing of said golf club.
16. The apparatus of claim 15, wherein said apparatus can selectively display said moving average golf club head speed value.
17. The apparatus of claim 16, wherein said moving average golf club head speed value is stored in a fourth area of computer memory so as to provide a user-specific average speed value for a given club.
18. The apparatus of claim 17, wherein, when said given club is a 1 wood driver, said user-specific average speed value may provide a weighted club parameter for other clubs, whereby distance for any club or club for any distance determinations may be made for that user.
19. The apparatus of claim 5, wherein said representative value is used to determine the approximate distance a typical golf ball would travel when struck by said golf club head moving at the speed represented by said representative value.
20. The apparatus of claim 19, wherein said approximate distance is determined by multiplying said representative value by a specific parameter, and wherein the value of said specific parameter is dependent on the type of golf club used.
21. The apparatus of claim 20, wherein said specific parameters range from 1.0 for a 1 wood driver to 0.60 for a pitching wedge.
22. The apparatus of claim 5, wherein said representative value is derived only if more than one-half of said "N" consecutive binary values are within a specified range.
23. The apparatus of claim 2, wherein said predetermined audio frequency range is between about 1 KHz and about 5 KHz.
24. The apparatus of claim 2, wherein said audio band pass characteristics of said audio amplifier means are such that there is a -3 dB point at about 1 kHz and at about 5 kHz.
25. The apparatus of claim 2, wherein said audio amplifier means is a high gain low noise amplifier.
26. The apparatus of claim 25, wherein said audio amplifier means has a gain of between about 50 dB and about 80 dB.
27. The apparatus of claim 2, wherein said trigger means is found in said microprocessor, and comprises means to determine the absolute value of the difference between pairs of consecutive stored values and compares said absolute value of the difference to a preset comparison value, wherein a counter is incremented if said absolute value of the difference is equal to or less than said preset comparison value, and wherein said counter is decremented if said absolute value of the difference is greater than said preset comparison value; and wherein when said counter reaches a predetermined number, said microprocessor uses a filtering algorithm to derive a representative value from said stored "N" consecutive binary values, which representative value relates to the speed of said golf club head during said detected golf club swing.
28. The apparatus of claim 27, wherein said predetermined number is an integer greater than or equal to 5.
29. The apparatus of claim 27, wherein said apparatus uses said representative value to calculate a speed value of the speed of the golf club head, and wherein said display means displays said speed value.
30. The apparatus of claim 27, wherein the number of periods measured and stored is greater than 20.
31. The apparatus of claim 27, wherein the number of periods measured and stored is in the range of from 20 to 120.
32. The apparatus of claim 28, wherein the number of periods measured and stored is in the range of from 30 to 70.
33. The apparatus of claim 31, wherein said representative value may be stored in a third area of computer memory.
34. The apparatus of claim 33, wherein the "M" most recently derived of said representative values are stored in temporally correct sequence in said third area of computer memory, and wherein "M" is a positive integer equal to or greater than 2.
35. The apparatus of claim 34, wherein "M" is in the range of 7 to 14.
36. The apparatus of claim 34, wherein said "M" derived representative values stored in said third area of computer memory are used to selectively calculate a moving average golf club head speed value that is exemplary of a typical swing of said golf club.
37. The apparatus of claim 36, wherein said apparatus can selectively display said moving average golf club head speed value.
38. The apparatus of claim 37, wherein said moving average golf club head speed value is stored in a fourth area of computer memory so as to provide a user-specific average speed value for a given club.
39. The apparatus of claim 38, wherein, when said given club is a 1 wood driver, said user-specific average speed value may provide a weighted club parameter for other clubs, whereby distance for any club or club for any distance determinations may be made for that user.
40. The apparatus of claim 29, wherein said representative value is used to determine the approximate distance a typical golf ball would travel when struck by said golf club head moving at the speed represented by said representative value.
41. The apparatus of claim 40, wherein said approximate distance is determined by multiplying said representative value by a specific parameter, and wherein the value of said specific parameter is dependent on the type of golf club used.
42. The apparatus of claim 41, wherein said specific parameters range from 1.0 for a 1 wood driver to 0.60 for a pitching wedge.
43. The apparatus of claim 27, wherein said representative value is derived only if more than one-half of said "N" consecutive binary values are within a specified range.
44. The apparatus of claim 18, wherein when a club for any distance determination is to be made, the approximate distance may be entered into a fifth area of the computer memory so that said approximate distance and a weighted club parameter may be used for a determination of a suggested club for the approximate distance.
45. The apparatus of claim 44, wherein said approximate distance entered in said fifth area of said computer memory is chosen from a default set of values from 200 yards to 100 yards, in decrements of 10 yards.
46. The apparatus of claim 39, wherein when a club for any distance determination is to be made, the approximate distance may be entered into a fifth area of the computer memory so that said approximate distance and a weighted club parameter may be used for a determination of a suggested club for the approximate distance.
47. The apparatus of claim 46, wherein said approximate distance entered in said fifth area of said computer memory is chosen from a default set of values from 200 yards to 100 yards, in decrements of 10 yards.
48. The apparatus of claim 2, wherein said microprocessor has a go-nogo determination algorithm to which said digital signal stream is referred when it is received by said microprocessor; and wherein said go-nogo determination algorithm with make a rough calculation as to the speed of the golf club head; means to issue a go-nogo signal when the result of said rough calculation as to the speed of the golf club head is below a predetermined value, whereby no further signal measuring steps will be taken.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US93916392A | 1992-09-02 | 1992-09-02 | |
| US07/939,163 | 1992-09-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2104761A1 true CA2104761A1 (en) | 1994-03-03 |
Family
ID=25472653
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2104761 Abandoned CA2104761A1 (en) | 1992-09-02 | 1993-08-24 | Electronic device to improve a golf swing |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2104761A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001038898A1 (en) * | 1999-11-22 | 2001-05-31 | Sportvision, Inc. | System for determining information about a golf club and/or a golf ball |
| US6292130B1 (en) | 1999-04-09 | 2001-09-18 | Sportvision, Inc. | System for determining the speed and/or timing of an object |
-
1993
- 1993-08-24 CA CA 2104761 patent/CA2104761A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6292130B1 (en) | 1999-04-09 | 2001-09-18 | Sportvision, Inc. | System for determining the speed and/or timing of an object |
| WO2001038898A1 (en) * | 1999-11-22 | 2001-05-31 | Sportvision, Inc. | System for determining information about a golf club and/or a golf ball |
| US6456232B1 (en) * | 1999-11-22 | 2002-09-24 | Sportvision, Inc. | System for determining information about a golf club and/or a golf ball |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US20020173365A1 (en) | System and method for controlling conditions in putting as a part of a golf game | |
| US4858922A (en) | Method and apparatus for determining the velocity and path of travel of a ball | |
| US8007367B2 (en) | Miniature radar for measuring club head speed and tempo | |
| US6148271A (en) | Speed, spin rate, and curve measuring device | |
| US5209483A (en) | Transducing and analyzing forces for instrumented sporting devices and the like | |
| US5401026A (en) | Method and apparatus for determining parameters of the motion of an object | |
| US10201739B2 (en) | Systems and methods for measuring and/or analyzing swing information | |
| US5700204A (en) | Projectile motion parameter determination device using successive approximation and high measurement angle speed sensor | |
| US5221082A (en) | Enhanced golf simulation system | |
| CA1329430C (en) | Electronic athletic equipment | |
| US6565449B2 (en) | Athletic ball impact measurement and display device | |
| US5131660A (en) | Putter | |
| US5984810A (en) | System for training a pitcher to pitch a baseball | |
| US4872687A (en) | Putting tutor | |
| EP2875504B1 (en) | Putting stroke analysis device | |
| US6371862B1 (en) | Game apparatus and method | |
| WO1999036859A1 (en) | A time of motion, speed, and trajectory height measuring device | |
| US20090137333A1 (en) | Golf putter assembly | |
| US20060029916A1 (en) | Golf putter for, system and method of training a golf player | |
| JP2000500229A (en) | Apparatus for measuring at least one physical parameter related to a propulsion ball under propulsion | |
| US20030017882A1 (en) | Sport apparatus with impact sensing and display | |
| CN87107996A (en) | The device of Measuring Object movement velocity | |
| US5082276A (en) | Distance measuring golf putting apparatus | |
| US20160271477A1 (en) | Correlating ball speed with putter speed | |
| US5788583A (en) | System for predicting the distance which will be imparted to a golf ball by a putting swing, and method for using same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |