Golf swing analysis apparatus and method
A method and integrated golf club apparatus for directly measuring physical parameters of the golf club head motional acceleration swing forces, golf club head face, golf ball impact forces, and subsequent calculations of other metrics useful to a golfer's understanding of the effectiveness of his or her golf swing and impact result in totality. The physical parameters that are directly measured include three dimensional motion force vectors of club head prior to, during and after impact and full impact pressure force profiles across the golf clubface with respect to time. The sensors are connected to electronics which condition, record and store the time varying sensors information electronically, then process and translate the information into one of several forms for delivery to a human interface function.
This patent application is a continuation-in-part application of patent application U.S. Ser. No. 12/287,303, filed Oct. 9, 2008, entitled Golf Swing Analysis Apparatus and Method.
FIELD OF THE INVENTIONThe present invention relates to a method for determining the effectiveness of a golfer's swing and the associated golf club head time varying force metrics before, during and after impact between a golf club head and a golf ball. More specifically, the present invention relates to an integrated golf club capable of autonomous direct measurement and information storage of three dimensional motional acceleration forces of the club head during the swing, and complete club head and ball impact time varying force profiles across the entire club head face.
BACKGROUND OF THE INVENTIONFor several decades, external systems separate from a golf club, or attaching sensors to a golf club, have been used to gather and infer information about the effectiveness of a golfer's swing. One of the most common external systems relates to using high speed cameras to determine metrics about a golfer's swing. Some of these systems estimate club head speed and ball speed and spin after the ball leaves the club. However, the true forces introduced in the clubface and the club/ball impact information are estimates based upon indirect calculations of force inferred from optical images.
The approach of using prior art golf club attachments can identify to an unacceptable approximate degree the impact area on the clubface. However, the precise location cannot be achieved because of the removable nature of the sensors and the lack of relationship of time varying force profiles of each sensor which is needed for a full energy impact analysis.
An example of such an external system is U.S. Pat. No. 4,136,387 to Sullivan et al., for a Golf Club Impact And Golf Ball Launching Monitoring System. Sullivan discloses a system that uses external electro-optical sensors to measure the location of a plurality of spots on the surface of the golf club head or the golf ball, each at two points in time. For the golf club head measurement the two points in time are just before ball impact; for the two points in time for the golf ball, it is after impact. This device does not offer an integrated golf club and does not allow for direct force measurements of the time varying spatial and force profiles across the clubface and club head accelerations' forces for accurate force dynamics associated with the club swing and clubface/ball impact.
Another example of an external system is the Patent Application Publication U.S. 2008/0020867 A1 to Manwaring for a method of determining a golfer's golf club head orientation and impact location for a golf swing. The system uses an optical CMOS imaging system to measure angular velocity of the golf club, linear velocity of the golf club, and ball launch properties. Then, through iterative calculations using the mass of the golf club and the ball, the device makes determinations as to club head orientation and clubface impact. This publication does not offer an integrated golf club and does not allow for direct force measurements of the time varying spatial and force profiles across the clubface and club head accelerations' forces for accurate force dynamics associated with the club swing and clubface/ball impact.
Another example of an external system is shown in U.S. Pat. No. 7,329,193 B2 to Plank, Jr. who claims a portable golf swing analyzing system separate from the golf club based on infrared sensors and ultrasonic sensors. This publication does not offer an integrated golf club and does not allow for direct force measurements of the time varying spatial and force profiles across the clubface and club head accelerations' forces for accurate force dynamics associated with the club swing and clubface/ball impact.
An example of attaching sensors to a golf club is shown in U.S. Pat. No. 4,898,389 to Plutt, who claims a self contained device for indicating the area of impact on the face of the club and the ball, and a means for an attachable and detachable sensor or sensor array that overlies the face of the club. Plutt's device does not provide for an imbedded impact sensor array in the clubface that functions in conjunction with internal three dimensional g-force sensors to provide a superset of time varying spatial force impact contours of the clubface with club head acceleration force parameters that can be calibrated for highly accurate spatial and force measurement. Plutt's device is susceptible to location inaccuracy due to the removable constraint of the sensors and is susceptible to sensor damage since the sensors come in direct contact with the ball.
Another example of attaching sensors to a golf club is shown in U.S. Pat. No. 7,264,555 B2 to Lee et al. which claims a diagnostic golf club system that utilizes a golf club with strain gauges or other swing load measuring means attached to the golf club shaft to determine swing characteristics. This device does not utilize sensors embedded with in the club head.
Another example of attaching sensors to a golf club is U.S. Pat. No. 5,792,000 to Weber et al. which claims a swing analysis system that analyzes sensors placed on the shaft of the golf club. This device does not utilize sensors embedded within the club head.
The prior art disclosures all fail to offer a fully integrated golf club capable of autonomously making time varying direct force measurements with regards to three dimensional motional forces of the club head before, during and after golf club head/ball impact, and making direct time varying force measurements across the clubface surface. Accordingly, none of the prior art aggregates all of these direct measurements with respect to a single time line allowing a large number of metrics to be calculated.
SUMMARY OF THE INVENTIONThe present invention is an integrated golf club that measures directly and stores time varying forces during the golf club swing in the time span around the point of golf club head and ball impact. Two categories of time varying forces are being measured in real time simultaneously with different mechanisms.
The first category of measured forces includes three dimensional motional acceleration forces on the club head during the club swing from a point in time before the initial club/ball impact until a point in time after club head and ball separation has taken place. The relationship between force and acceleration is {right arrow over (F)}(t)=mch{right arrow over (a)}(t) where {right arrow over (F)}(t) is the time varying force vector, mch is the known mass of the club head and {right arrow over (a)}(t) is the time varying acceleration vector experienced by a given acceleration force sensor. The three dimensional axial domain of the acceleration force vectors has its origin at the center of gravity and the axial domain is orientated with one axis referenced normal to the club head face. The mechanism used to measure this category of motional forces is a three dimensional g-force acceleration sensor or sensors.
The second category of force measurements includes the impact pressure forces that occur across the golf club head face for the duration of clubface and ball impact. This time varying pressure force is a scalar pressure profile normal to the clubface that is a result of the impact force and location of the ball on the clubface. The relationship between pressure and force is P(t)={right arrow over (F)}normal-to-A(t)A where P(t) is the time varying pressure experienced by a given pressure force sensor, {right arrow over (F)}normal-to-A(t) is the time varying vector component of the force vector that is normal to the surface of the pressure force sensor and also the clubface, and A is the surface area of a given pressure force sensor. The axial reference domain is the same for the g-force sensors described above. The mechanism to measure this category of pressure forces is an array or pressure force sensors embedded in the clubface that are measuring time varying impact pressure forces across the clubface during the entire duration of club head face and ball impact.
Both categories of dynamic direct vector measurements are related with a single time line and a single shared physical domain allowing a large number highly accurate golf club swing, club/ball impact and club head to ball orientation metrics to be realized. To achieve this aggregate of direct physical measurements, the golf club head has embedded within it at least one acceleration three dimensional g-force sensor and at least one, but preferably a plurality of impact pressure force sensors geometrically distributed in the club head face. From the aggregate related measurements of these two measurement systems associated with a single time line and a defined spatial relationship to each other and to the club head physical structure, the following metrics are either directly measured or directly calculated (If a metric calculation requires an assumption, such as ball surface condition and hence friction coefficient, its is stated as an estimate):
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- 1. Time varying pressure or force profile across the golf clubface;
- 2. Location of impact of clubface and ball on clubface;
- 3. Duration in time of club head face and ball impact;
- 4. Maximum pressure or force measured on clubface;
- 5. Total energy transferred from club to ball;
- 6. Time varying three dimensional motional acceleration and associated force vectors on club head before, during and after club head face and ball impact;
- 7. Radial acceleration forces on club for estimation of club head velocity;
- 8. Three dimensional deceleration force vectors of club head during the club/ball impact;
- 9. Force vector components that are transferred to ball launch and ball spin;
- 10. Estimated percent of total energy components transferred to ball trajectory and ball spin;
- 11. Club head orientation with respect to ball from before club head/ball impact, during ball impact and after impact;
- 12. Orientation of ball spin referenced to club head face;
- 13. Estimation of ball launch velocity;
- 14. Estimation of ball spin velocity;
- 15. Impact error offset on clubface which is a distance from actual impact location to optimum impact location;
- 16. Club head orientation percentage error from optimum in relation to club head/ball impact (This could be described as a error for each of three vectors describing forces on club head from ball) and;
- 17. Measure of torque and angular momentum of the club head as caused by the event of club head/ball impact.
The sensors are connected to electrical analog and digital circuitry, also embedded in the club head, that condition the signals from the sensors, samples the signals from all sensors simultaneously, converts to a digital format, attaches a time stamp to each group of simultaneous sensor measurements, and then stores the data in memory. The process of sampling sensors simultaneously is sequentially repeated at a fast rate so that all forces' profile points from each sensor are relatively smooth with respect to time. The minimum sampling rate is the “Nyquist rate” of the highest significant and pertinent frequency domain component of the sensors' time wave for any of the sensors.
Thus, the present invention encompasses a variety of options for the golfer to receive and interpret the information of swing, impact and orientation metrics or a subset of total metrics available. The human interface function can be either integrated into the club or a separate human interface module that the golf club communicates with either through wires or wirelessly. The human interface function can be all or any subset of audible, visual, temperature or vibration signals for human interpretation.
A further advantage of the present invention is that in its preferred embodiment, the integrated club communicates with an external human interface apparatus through a wireless connection. The wireless connection could be Bluetooth™, Zigbee™, Wifi or any number of standardized or non standardized radio frequency communication links. There are many possible implementations for the human interface apparatus that support both visual and audio content for human interpretation. Some examples are: laptop computer, palmtop computer, PDA, smart phone, or a thick or thin client video audio custom device. For purposes of descriptive clarity, the preferred embodiment will use a wireless Bluetooth™ data link, and the human interface apparatus is a laptop computer.
Therefore, the preferred embodiment the integrated golf club, in addition to the previous described electronics, also has data formatting for wireless transport using Bluetooth™ transceiver protocols. The data, once transferred over the wireless link to the laptop computer, are processed and formatted into visual and or audio content with a proprietary software program specific for this invention. Examples of user selectable information formats and content could be:
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- 1. a dialog window showing a graphical representation of the clubface using a color force representation of the maximum force gradient achieved conveying the area of impact of the ball and along the side the graphic could show text describing key metrics such as maximum force achieved, radial acceleration of club at impact (related to club head velocity) and total energy transferred to the ball;
- 2. a motion video of the time varying nature of the forces on the clubface;
- 3. a three dimensional graphic showing force vectors on club head from ball;
- 4. an audio response which verbally speaks to the golfer telling him/her the desired metrics;
- 5. a video showing time varying acceleration vectors of the golf club head during the swing and through impact; or
- 6. numerous other combinations of audio and visual user defined.
Still yet another advantage of the present invention provides for the integrated golf club that can be battery operated, or have batteries that are rechargeable or replaceable.
The above and other features of the present invention will become more apparent upon reading the following detailed description in conjunction with the accompanying drawings, in which:
The present invention comprises an integrated golf club that measures directly and stores time varying forces during the golf club swing in the time span from before the golf club head and ball impact, to a point in time after club head and ball separation. Two categories of physical parameters are being measured in real time simultaneously with different mechanisms that both convert directly to time varying force vectors. The force vectors from each measurement mechanism are interdependent in time and fixed spatial relation to one another as the club head transitions through all of the different dynamic forces during a golf swing, ball impact and after impact.
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The non-conducting monolith material 15 with embedded pressure sensors 30 can be pressure fit between the outer layer 13 and the inner layer 14. The outer layer 13 and the inner layer 14 can be connected to the club head housing 16 with conventional club head construction techniques utilizing weld seams. Some techniques might include Aluminum MIG (Metal Inert Gas) welding for aluminum to aluminum connection and brazing for aluminum to titanium connections. The clubface layers 13 and 14 can be titanium or comparable metal or alloy and the club head housing components can be an aluminum alloy.
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- 1. Total energy transferred from club to ball;
- 2. Time varying three dimensional motional acceleration and associated force vectors on club head before, during and after club head face and ball impact;
- 3. Radial acceleration forces on the club for an estimation of club head velocity;
- 4. Three dimensional deceleration force vectors of club head during the club/ball impact;
Although specific embodiments of the invention have been disclosed, those having ordinary skill in the art will understand that changes can be made to the specific embodiments without departing form the spirit and scope of the invention. The scope of the invention is not to be restricted, therefore, to the specific embodiments. Furthermore, it is intended that the appended claims cover any and all such applications, modifications, and embodiments within the scope of the present invention.
Claims
1. A golf club head comprising at least one internal three dimensional motional acceleration force sensor, and at least one internal impact pressure force sensor.
2. The golf club head of claim 1, further comprising a golf club head face, wherein said at least one internal impact pressure force sensor is embedded in a monolith within said face.
3. The golf club head of claim 1, further comprising electronic circuitry internal to said head, and connected to said sensors.
4. A golf club comprising, in combination, a golf club shaft and a golf club head, the head further comprising at least one internal three dimensional motional acceleration force sensor, and at least one internal impact pressure force sensor.
5. The combination of a golf club and a human interface interactive with said club, said club comprising
- a golf club shaft;
- a golf club head connected to said shaft wherein said head comprises at least one internal three dimensional motional acceleration force sensor, and at least one internal impact pressure force sensor;
- electronic circuitry internal to said head and connected to said sensors wherein the said circuitry captures golf swing dynamics data from said sensors relative to said golf club striking a golf ball; and
- means of transmitting said data to said human interface.
6. The golf club and human interface combination of claim 5, wherein the human interface further comprises a group consisting of audio, visual, thermal and vibratory signals.
7. A golf club having a head comprising at least one internal three dimensional acceleration force sensor for measuring motional forces of said head relative to the striking of a golf ball.
8. A method of capturing golf swing dynamics data from swinging a golf club and transmitting said data to a human interface, the steps comprising:
- providing a golf club having a golf club shaft, and a golf club head connected to said shaft, such that said head has at least one internal three dimensional motional acceleration force sensor;
- connecting said sensor to electronic circuitry internal to said head wherein the said circuitry captures golf swing dynamics data from said sensor relative to swinging said golf club; and
- providing means for transmitting said data to said human interface.
9. The method of claim 8, wherein said club head further comprises a club head face, said steps further comprising:
- providing at least one impact pressure force sensor embedded within said face of said golf club head;
- connecting said circuitry to both types of sensors wherein the said circuitry captures golf swing dynamics data from said sensors relative to striking a golf ball with the said golf club, and;
- providing means for transmitting said data to said human interface.
10. The method of claim 9, said steps further comprising providing means for storing of said data after the transmission of said data.
11. The method of claim 9, said steps further comprising providing means for calibrating said at least one pressure force sensor relative to its location within said face.
12. A golf club comprising, in combination,
- a golf club head;
- a shaft connected to said head;
- at least one internal acceleration force sensor having spatial dimensionality comprising at least one dimension, and;
- electronic circuitry comprising data collection and processing means for display through a human interface.
13. The golf club of claim 12, comprising two internal acceleration force sensors having at least one dimension of spatial measurement.
14. The golf club of claim 12, wherein said human interface is disposed on said shaft.
15. A golf club comprising an attachable and detachable system having at least one club head attachment module external to said club head wherein the said attachment module comprises one or more acceleration g-force sensors, and electronics for wired or wireless transmission of sensor data to a receiver module human interface.
Type: Application
Filed: Dec 24, 2008
Publication Date: Apr 15, 2010
Inventors: Roger Davenport (Ft. Lauderdale, FL), Paul Reynolds (Mountain View, CA)
Application Number: 12/317,435
International Classification: A63B 69/36 (20060101);