NL1020131C1 - Method and device for measuring and presenting parameters when striking an object to be moved with the aid of an impact tool. - Google Patents

Description

5

Short indication:

Method and device for measuring and presenting parameters when striking an object to be moved with the aid of an impact tool.

The invention relates to a method for measuring parameters when a percussion tool, such as a tennis, badminton, table tennis, or squash racket, cricket bat, hockey stick or the like percussion tool, strikes against a striking face of the percussion tool on a striking surface object to be displaced, such as a ball or puck, wherein at least one sensor system connected to the percussion tool, at least when it comes into contact with the object to be displaced, signals are supplied to a computer which at least calculates the speed of the displaced object therefrom and furthermore the position of its tangent on the face determines which speed and position are presented on one or more presentation devices, such as a panel, sheet or screen.

This method is known from the German "Patentschrift" 34 36 218.

In this known method use is made of strain gauges that can only be stretched in a single direction as sensors, from which the force exerted on site can be calculated as a result of the deformation of the strain gauges, and as a result of this calculation within an (un) certain margin the speed of the object to be moved relative to the percussion tool can be determined. By a geometric arrangement of the sensors on the percussion tool, the position of the contact point can be indicated fairly accurately.

With these values, the player or his coach already has some information about the performance of the player and can draw indications for improving his sporting performance.

Because a number of important values are left out of consideration, such as the speed and acceleration of the percussion tool, the spatial direction of the percussion tool as a function of the direction in which the work to be moved hits the percussion surface of the percussion tool and the angle that the percussion tool relative to takes the point of contact, accurate and optimum information about the performance of the player cannot yet be derived from the known method.

1020131 2

The method according to the invention has for its object to improve that of the type mentioned in the preamble in this respect and is to that end characterized in that the acceleration and the position of the percussion tool during the swinging movement and the collision with the object to be displaced are measured in three transverse superimposed directions, from which measurement the direction and speed of the displaced object and of the percussion tool are accurately determined, for example with a computer or the like, and displayed on a presentation device, wherein, if the measurement is repeated on successive strokes at the the graphic image and / or statistical diagram shown on the presentation device also the time span between the beats and the velocity course during those successive beats are relative;

It is to be noted that European patent application 0.407.631 discloses a method for testing a tennis racket, wherein forces are measured in three directions perpendicular to each other and the results thereof are applied to a computer included in the handle of the racket. .

On the basis of the evaluation of the data of a number of rackets tested in this way, the choice is then made for the purchase of a racket with the best geometry suitable for the player and the best of the construction materials used thereby.

With this known method, giving specific instructions to the player is not primarily thought of.

Preferably, in the method according to the invention for improving the performance of the player, a summary is also given of the number of strokes performed as well as the number of good and bad strokes thereby, for which purpose this preferred method is characterized in that the sensors control both the acceleration and the swing. pick up with the percussion tool in the event of a collision with the ball at the front as well as in the event of a collision at the rear of the percussion tool;

For example, a "paddle" is known per se from American "Patent" 5,816,580, which is provided on each of the two sides with a face that each carries a sensor to be able to record the collision with a bat and to send a signal thereto to a counter . The aim of the game is to hit the ball back with a different side each time. The counter indicates when a mistake has been made and the counterparty has then "scored a point." 1020131 3

This registration therefore has nothing to do with games where a "forehand" or "backhand" stroke must be applied depending on the game position. In a further developed method according to the invention, in addition to acceleration, the magnitude and frequency of the collision in three perpendicular directions are also measured, in order to determine which collision position on the face causes the smallest amplitude of vibrations and thus is most effective.

Reference is made in this connection to the method according to the American patent 6,134,965, in which it is already indicated to determine the vibration caused by the collision of the ball with the interface, in order to, after studying the graphs of a series of strokes, determine the position of be able to display the point of contact on the tangent plane that represents the lowest amplitude in a collision with the ball. In this method, the sensor is placed on the interface, which is designed as a wire tension, with the chance that the sensitive sensor will be hit by a ball, the sensor then being damaged. Moreover, this known method does not involve the use of three-way sensitive acceleration sensors.

The invention further comprises a device for performing the method according to claim 1, comprising an percussion tool, such as a racket, bat or stick., And at least one sensor connected to the percussion tool for issuing measurement signals in the event of an object to be moved with striking face arranged at least on one side of the percussion tool, which according to the invention is provided with a sensor system, the sensor of which is, or sensors are adapted to receive the magnitude of accelerations in three directions perpendicular to each other, which sensor or sensors for issuing recorded signals is or are connected to a computer, directly or indirectly connected to the percussion tool, for determining the desired data, such as speed and direction of the discarded object, accurate indication of the point of contact, number and intensity of the strokes, etc., which data can be displayed on one or more presentation devices, such as a display, paper strip or the like.

It is noted that U.S. Patent 5,351,952 discloses a method for measuring acceleration during the golf game in which the golf stick is provided near the face with an acceleration sensor, one and the other 1020131 4 such that it swings downwards, a high acceleration is measured and when the acceleration is greatest, the face hits the ball, after which the stick still blows with a negative acceleration.

The accelerations experienced by the sensor during each of the 5 successive beats are fed as many signals to a computer which is connected to a presentation device on which the acceleration trend during the swing and collision during those successive beats can be displayed. In this way the player can be accurately informed about the good and the wrong hits, so that the player can change his striking technique in a favorable way.

The mentioned and further features of the invention will be further explained below with reference to the drawing of an example of one of the possible methods and devices according to the invention.

In the drawing represent: fig. 1: a tennis racket drawn in the forehand position provided with a housing arranged on the handle, in which a sensor system is accommodated; Fig. 2: a schematic representation of the electronic processing of the recorded signals; fig. 3: graphic representation of the centripetal forces and the collisions with the ball on the racket; Fig. 4: Graphical representation of the vibrations on the racket with a "good" and "bad" chosen spot.

The tennis racket 1 is provided with a contact surface 2 consisting of a wire covering, which depending on the playing position on the front or rear side 25 can be used for striking away a ball. To this end, the racket undergoes a swinging movement W, drawn here in the position in which the front side of the face is used, and thereby experiences a centripetal force. The magnitudes of the resulting accelerations are recorded in the "X", "Y" and "Z" direction by a sensor system 3, which outputs corresponding signals to a computer, for example a micro-computer incorporated in the handle, which with a signal wire or wirelessly connects to a remotely arranged, (not shown) presentation device, such as a screen, XY writer or the like or to a mini-screen or the like arranged on the racket.

10 201 31.

5

Because the acceleration, particularly in the "Z" direction, can reach a value of 2000 G, while only small accelerations (approx. 2 G) occur for registering the points of contact or changes from "forehand" to "backhand" the preference for these extreme differences is therefore to use separate more or less sensitive sensors aimed at those gears.

Figure 2 shows diagrammatically the electronic way in which the signals from the three of the acceleration sensors, 3x, 3y, 3z, are applied via signal amplifiers 4 and an analog / digital converter 5 to a microprocessor 6, which on the one hand is connected to a storage / memory 7 and 10, on the other hand, with a presentation device, such as a PC 8. With control buttons 9, a choice can be made between the different images to be displayed, for example, after a competition or after a series of strokes.

The recorded signals are converted in the computer so that the following data can be provided on the presentation device: - time period between successive strokes; - racket speed prior to hitting the ball - "fore or backhand" service (yes / no) 20 - max. amplitude of the vibrations -max. acceleration in 'z' direction (measure of the ball speed) - touch point of the ball on the interface of the racket - number of strokes per time unit; -total number of strokes; 25 prompts "in" or "out".

With this data, the player or the trainer can, by analyzing a large number of different game technical qualities, get an impression of the player's game quality and also see which techniques of the game still need adjustments or improvements.

Figure 3 shows diagrammatically both the centripetal forces along the three axes "Cx, Cy, Cz" and the collisions "B", whereby the magnitudes of the accelerations prevailing during those subsequent collisions are clearly visible.

10201 3U

6

Figure 4 clearly shows the difference between a strong vibration-generating stroke when the ball hits an interface at an incorrect position and from a relatively small vibration at a correct position.

It is with the aid of the game data that can be provided with the device according to the invention to combine the data on the "timing" with the data on the acceleration. By measuring the passage of time between successive strokes, all kinds of information / conclusions can be derived based on heuristics. For example, if the player serves 10 and the ball is out, then it will almost certainly be served again within 3 to 5 seconds without any other kind of tennis beating in the meantime. In other words: all kinds of conclusions can be drawn through knowledge of the game (the rules), the type of hits and heuristics. For example, in the aforementioned case it is easy to accurately determine how many first 15 services there were in, what the speed difference was between the first and second services and whether they were aimed at the opponent's “fore or backhand”. (Player A serves, player B receives the ball a tenth second later).

Furthermore, for example, the data recorded on the one hand by one of the sensor systems according to the invention can be attached not only to the percussion wood but also to the wrist or hand of a baseball pitcher, and the calculated angular rotations and accelerations and parameters derived therefrom can be combined with each other .

That way, for example, it can be measured with which type of throws (speed and with what kind of effect) the batter has the most difficulty.

Furthermore, with the device according to the invention, it is without any doubt possible to have the player give game instructions to the player during game or training, for example with an audio signal (so-called "direct teaching")

By applying the methods according to the invention, the athletes can train more efficiently. For example, during training they receive instruction to practice their backhand “service return” extra.

The coaching or training information could also be communicated during the training by means of a speech generation module connected to the computer. Computer and speech generator could work independently of the bat or be integrated into it.

1020131 7

It is self-evident that, when the position of the racket relative to the playing field is also recorded, the place where the ball is contacted with the racket, combined with the point of contact of the ball with the racket, is acceptable precisely where the ball will hit the playing field, it can be calculated, while it can also be deduced from the measured location of the hit point whether it has been hit "in" or not and, for example, whether it is hit with 10 "topspin".

These and other game situations can, thanks to the method according to the invention, be stored in the memory of the computer and made visible on the presentation device at any desired moment, for example for evaluating a training or a competition. - 20 25 1 1020131

Claims (2)

1. The invention relates to a method for measuring and calculating parameters when striking an impact tool at an impact site, such as a tennis, badminton, table tennis, or squash racket, cricket bat, hockey stick or the like. striking an object to be moved, such as a ball, shuttle or puck, wherein at least one sensor system connected to the percussion tool with at least one sensor at least when it comes into contact with the object to be moved, signals are output to a computer which which signals at least calculates the speed 10 of displaced object and furthermore determines the position of the tangent site on the face, which speed and position are presented on one or more presentation devices, such as a panel, sheet or screen, characterized in that the acceleration and the position of the percussion tool during the swinging movement and the collision with the object to be moved is measured in three transverse directions 15 directions, from which measurement the direction and speed of the displaced object and the acceleration of the percussion tool are accurately determined, for example with a computer or the like, and displayed on a presentation device and repeated and displayed by measuring successive strokes by means of a graphical representation and / or statistical diagram which also takes into account the measured time span between the beats and the speed trend during those successive beats; 2. Method as claimed in claim 1, characterized in that the sensors detect the acceleration both the swing with the percussion tool in the event of a collision with the ball at the front as well as in the case of a collision at the rear of the percussion tool; Method for one or more of the preceding claims, characterized in that the number of strokes of the percussion tool are recorded and presented both in the event of a collision with the object to be moved at the rear and in the case of a collision at the front; Method according to claim 1, characterized in that, in addition to the acceleration measurement, the sensor system is sensitive to vibrations in the interface, the signals of the amplitude and frequency of which are transmitted to the computer, from which the position of the tangent point within the interface collided with that at 1020131. causes the lowest amplitude with the object to be moved. 5. Device for performing the method as claimed in claim 1, comprising an percussion tool, such as a racket, bat or stick., And at least one sensor system connected to the percussion tool for issuing measurement signals in the collision of an object to be moved with at least on striking face arranged on one side of the percussion tool, characterized in that the sensor system is the sensor or sensors are adapted to receive the magnitude of accelerations in three directions perpendicular to each other, which sensor system is connected for delivering recorded signals. on a computer also connected to the percussion tool for determining the acceleration of the percussion tool during the collision and the direction and speed of the object to be moved after the collision, the values of which can be displayed on one or more presentation elements, such as screen, paper strip or the like; 6. device for performing the method according to claim 1, comprising an percussion tool, such as a racket, bat or stick, and at least one sensor connected to the percussion tool for issuing measurement signals in the event of an object to be moved colliding with the percussion tool, characterized in that the sensor system is adapted to record the magnitude of accelerations in three directions perpendicular to each other, which sensor system is connected to a signal amplifier and a connecting element is present for transmitting the signals to a computer located at a distance from the percussion tool for determining data, such as speed and / or direction of the object to be moved after collision with the percussion tool, which data can be displayed on one or more presentation devices, such as a screen, XY writer, paper strip or the like; 7. Device as claimed in claim 5 or 6, characterized in that the percussion tool is provided on both the front side and the rear side with an percussion surface and that the sensor system is adapted to deliver the signals associated with accelerations during the swing of the percussion tool and the collision with the object to be moved. Device as claimed in any of the foregoing claims 5-7, characterized in that in the sensor system, of the sensors sensitive to X, Y and Z direction, at least one for high G values and / or at least one for low G values include sensitive sensors. 5 -oooOooo-1020131