HU177615B - Arrangement for the automatic telemetry at the ski-jump - Google Patents

Abstract

The automatic Weifcenmessung for ski jumping with MeBinduktions * loop and permanent magnet to the disadvantages of the currently common visual method sov / ie the currently known, but in practice have not become effective automatic method eliminate. Required is a measurement accuracy of 0.5 0 m. The parts, which must be attached to the skis or jumpers themselves, should be maintenance-free and should not exceed a mass of 15 g. Environmental influences must not impair the function of the system. According to the invention, the area of the landing area is covered with MeBinduktionsschleifen at intervals of 0.50 m. They are laid at right angles to the direction of flight under the snow or under the mat covering. On the jump ki a permanent magnet is attached. After completion of the jumpers' flight phase, signals are induced in the binding loops. An electronic circuit detects the-MeBinduktionsschleife in which a signal was first induced as a measure of the cracked width. A control induction loop is used to check the system and to optimize the gain of the o ...... iZliSitZ measuring induction loop amplifiers.

Description

The present invention relates to an arrangement for automatic distance measurement at a ski jump. The arrangement applies to all ski jumpers.

For a ski jump, the jump distance is the distance between the edge of the jump table (jump position) and the landing site. The latter has so far been visually determined for all ramps, ie judges on one side of the slope. According to the rules, the judges are so far apart that they each observe a three-meter section.

The distance is measured when both skis are completely exposed to the snow or carpet. The position of the ski bindings or the center line of the two bindings when the telemark reaches the ground is then observed. Measurements of up to four meters can occur with this visual determination. The main reasons for this are:

- as the ski jump speed is approximately 100 km / h on the main landing, due to the inertia of the human eye, the exact position of the landing cannot be determined

- when jumping, often the different light and weather conditions make it difficult to accurately locate the landing;

.— Competitors may intentionally assist or disadvantage a ski jumper.

It is also disadvantageous that many people are required to visually determine the jump distance. The consequence of this is that, in practice, the jumping distance is usually only approximated, as in most cases there are not enough judges available.

In addition to the visual method that has been used hitherto, there are also some methods that can be used to perform distance measurement with greater accuracy and without subjectivity. These include:

- radiation barrier method;

- ultrasonic distance measuring systems (echolotelv);

- a laser barrier measuring system with pulse recording by induction loop 10;

- laser infrared measuring system with slope sensors:

- direct inductive menader system with simple encoders;

—Radar ESM system (ESM = Electronic Ski Jump Distance Measurement Equipment).

These procedures are briefly described below:

In the beam barrier method, beam paths (optically or acoustically) are located at defined distances along the slope, in which the beam direction is perpendicular to the direction of the jump. Very low rays are interrupted when the ski jumper reaches the main. The distance determined depends strongly on the way the jumping ground is caught. Environmental factors can also adversely affect reliability (snowfall, fog, backlight, icing, noise). In addition, the maintenance costs are quite high.

In an ultrasonic distance measuring system (echolot principle), the time of landing is indicated by a transmitter. This is where the distance measurement starts. The practical application of this method is unknown. In snowfall and fog, damping of ultrasonic waves is disadvantageous. Wind noise can also interfere. Interfering sound can completely prevent operation. The reflective properties of a sportswear can also be very different. Jumpers must carry a beacon to indicate the time of landing.

Laser Barrier Measurement System With Pulse Capture by Induction Loop (Falun / Sweden, 1974), laser infrared barriers are located at defined distances along the slope. The direction of the beam is perpendicular to the direction of the jump. The devices are located directly above the snow, thus interrupting the beam when jumping to the ground. A suitable transducer, when the ski reaches the ground, provides an electromagnetic signal pulse, which is detected by an induction loop covering the entire downhill section of the slope and initiates the timing. The time that elapses before the next laser barrier is interrupted is recorded. They then determine the amount of time that will elapse before the next laser barrier is interrupted. Because the distance between the laser barriers is known, the landing position can be calculated by assuming that speed and posture do not change. It is a disadvantage that errors in speed and posture can occur, and the laser bars must always be adjusted to different snow heights. A further major disadvantage of this procedure is that the jumpers have to carry a costly transmitter with them. Deliberate external interference is also possible.

With the laser infrared measuring system, slope sensors are equipped with an infrared laser transmitter on the ski jumper's shoes, which is approximately 3 to 10 " ⁶ sec at the moment of landing. emits a pulse of long length perpendicular to the direction of the jump to one side. This beam reaches the sensor rails at a height of about 1 meter along the downhill slope, and controls a series of infrared sensors according to the beam width. An electronic circuit then determines the center of the affected range and specifies the length of the jump.

This system also has several disadvantages:

- adjust the sensor rails to the change in snow height;

- the sensor rails are fully exposed to the weather;

- place a small device on the skis or shoes that produces the laser pulses; jumpers require a cable connection between the battery, the starter contact, and the laser pulse transmitter.

The direct inductive meander system with simple encoders on the track has not yet been tested. The contact on the shoe shortens an inductance at the moment of landing. The hopper is provided with a meander-shaped cable loop running transversely back and forth to the path and supplied with a current of approximately 70 Hz. Between two adjacent wires, in the middle are simple wires, which are normally free of current. If the equilibrium is disrupted by touching the inductivity upon landing, a signal is generated in the middle conductors. An electrical circuit then determines the location of the landing. The difficulty with this solution is that a large number of test leads (middle leads) must be kept free of power for a long period of time despite all possible external influences. The jumper must carry a contact and a coil.

The radar-ESM system uses a beacon, a push-button, and a radar reflector, which are used to mount the ski jumper, to determine the point of capture. Two CW radar devices measure the distance at the bottom of the barn. They are mounted on the right and left sides of the runway at a height of about 10 meters at the height of the rock table. Another radar device, mounted directly on the rock table, measures the distance in the upper range.

The main disadvantages of this solution are:

- ski jumpers must be equipped with special equipment;

- high costs;

- costly maintenance of jumper equipment.

Information on the above procedures is from K. Kriselmeyer, M. Bolkart, K. H. Schmall, Elektronische Sprungweitenmessung, Voraussetzung - Stand Ausblick, Verlag, W. Steinbrück Baden-Baden (1976).

In summary, the above-described variants of automatic distance measurement have the following disadvantages:

- the skipper is carrying on the skis or in his own private gear equipment which is relatively heavy to be maintained and which impedes the athlete;

The known methods have a relatively high interference sensitivity to environmental influences and external manipulation;

- the equipment required is quite expensive.

It is an object of the present invention to provide an arrangement for automatic distance measurement at a ski jump that performs its function well, requires no major maintenance, is free of all subjectivity, is insensitive to environmental influences and is inexpensive.

The proposed layout takes a whole new approach to the task at hand. In the variants known so far, the base is that the ski jumper arrives at a very flat angle to the slope plane. Therefore, to determine the location of the landing, it has so far been necessary to produce a limited signal at the time of the ground capture, taken with a receiver and evaluated appropriately. The jumper had to carry a relatively heavy transmitter to provide the required signal strength. As a result, efforts have been made to increase the sensitivity of the receiver equipment or to find new, more favorable transmission principles. Meanwhile, it has not been recognized that by exploiting the features of ski jumping, the 177615 acids offer entirely new possibilities for automatic distance measurement arrangements.

The proposed arrangement is based on inductive measuring loops (receiving antennas) known per se over the entire surface of the hopper landing area. They are placed under the snow or carpet, preferably at a distance of 0.5 meters, perpendicular to the expected flight direction. A suitable signal amplifier is connected to each induction measuring loop. The skis are fitted with a known small rod-shaped permanent magnet prior to bonding. Athletes determine which ski to mount the permanent magnet on. When the ski jumper arrives, the distance between the permanent magnet on the ski and the induction measuring loop will be so small that an electrical signal is induced. These signals are fed through amplifiers and signal wires to a central unit. Amplifiers are located in close proximity to the outputs of the induction measuring loops.

The central unit is assigned a storage location for each signal. An electronic logic circuit determines the storage location to which the signal first arrived by querying the container. Each induction gauge loop, and thus each storage location, is assigned a specific distance, measured from the edge of the rocking table. Because the induction measuring loop is spaced every 0.5 meters, it can be measured with an accuracy of 0.5 meters. The jump distance determined in this way can be immediately displayed with numeric display units and printed on suitable printers. The procedure described is applicable up to a maximum snow depth of 0.8 meters.

The different snow heights require that the amplification of the induction loop amplifiers be varied or optimally adjusted. This can, among other things, prevent the induction of signals in several induction measuring loops at the same time. Examination of the soil trapping technique shows that the diver first lands on the back end of the skis and only then on the ski nose, resulting in a high relative speed of the ski nose. Therefore, care should be taken to place the permanent magnet on the skis relatively far before the bonding, since in this way the distance between the permanent magnet and the induction gauge loops can be reduced rapidly before the completion of the flight phase. The low weight of the permanent magnet, about 12 grams, does not hinder it.

A control induction loop (transmitting antenna) is used to set the optimum gain of the inductive loop loop amplifiers (manual or automatic) and to test the operation of most distance measuring equipment. This is located at the edge of the jumping slope, on the snow or carpet, approximately perpendicular to the induction measuring loops. The control induction loop is powered by electrical signals such that the signals induced in the induction measuring loops are similar to those generated by a permanent magnet. During the verification process, the gain is varied in specific steps until the amplitude of the amplified signals of the induction measuring loops corresponds to a preset value. The gain thus determined is maintained until the next test.

The advantages of the invention are as follows:

- simple construction of the whole distance measuring device;

- high accuracy in measuring the distance traveled;

- reliable operation;

- low maintenance costs;

- low interference sensitivity to environmental influences and external manipulation;

- low weight of the jump device;

- relatively low purchase and installation costs.

The invention will now be described in more detail with reference to an exemplary embodiment and a drawing.

In the drawing, Fig. 1 is a jumping slope of a skipping rope with an automatic distance measurement arrangement, and Fig. 2 is a skipping rope with a permanent magnet placed thereon and an enlarged magnet.

Fig. 1 shows the slope 1 and the rocking table 2. In the arrival area, at the locations x _t , x ₂ , ..., x _n, the induction measuring loops 3 are arranged which are connected via the amplifier 5 to a central unit consisting of a logic unit, a printer and a display. The control induction loop 4 fed through the power amplifier 6 covers all the induction loops.

The induction measuring loops consist of a single thread that spans the entire required landing path width. The outgoing and return wires are parallel and are 0.2 meters apart. The loops are positioned transversely to the downhill slope so that the plane of the loop is parallel to the snow surface. Preferably, the induction measuring loops consist of an insulated litze wire of sufficient mechanical strength. To avoid the risk of accident, the induction measuring loops must be placed under the carpet when jumping on a carpet, and under the snow when jumping on a snow or, if a net is used, in its eyes. The induction measuring loops must always be positioned so that they do not endanger the ski jumpers in any way.

Care should be taken to ensure that the upstream and downstream wires of the induction measuring loops are always assigned to the correct amplifier input. The signal wires from the induction loops to the amplifier, as well as the wires connecting the amplifier to the central unit, are shielded.

The amplifiers have a symmetrical input. Their properties are as follows:

- major suppression of single phase signals;

- a bandwidth of 20 Hz to 40 Hz;

- 50 Hz closing filter;

- automatic optimum gain adjustment in the range 1 · 10 ^{3 to} 150 · 10 ³ ;

- threshold switches.

The signals of each measuring point are routed through the input circuits of a standard interface to the storage units of the central unit. From there, they are placed in a step register, which outputs signals in series. The number of incremental steps required to move the first loaded storage location to the output represents the amount of jumped distance. The corresponding incremental strokes are counted by a counter preset to a distance corresponding to the distance of the first induction loops.

Since the permanent magnet is placed before the bond, the result of the distance measurement must be reduced electronically accordingly. The result is then displayed in a numeric display unit and printed using printers.

The control induction loop also consists of a single strand and is made of insulated litze wire. The distance between the wires is kept by a plastic film strip at 0.2 meters. When not in use, the control loop 5 is stored, preferably due to its length (all induction loops must pass), on a reel. The control induction loop is extended to the snow or carpet before the jumps to check the distance measuring device 10 and optimize the amplification of the induction loop loops. The control loop is powered by a sinusoidal current from a generator in the frequency range of 20 Hz to 40 Hz and approximately 3 amps. 15

Figure 2 shows the location of the permanent magnet on the ski. Preferably, the permanent magnet is glued or screwed to the web using a flange sleeve or a rubber jacket. The permanent magnet, together with the clamps, weighs approximately 12 grams and measures 8 x 20 by 15 mm. The magnetic polarity must always be set the same during installation.

Claims (3)

Patent claims Arrangement for automatic distance measurement at a ski jump, comprising a permanent magnet and an induction loop, characterized in that the ski preferably has a permanent magnet on the ski and an induction loop, preferably perpendicular to the flight direction of the ski jump on the downhill slope (1). (3) are arranged to which variable gain amplifiers (5) are connected, which amplifiers (5) are connected to a central unit consisting of a logic unit, a printer and a display. An embodiment of the arrangement according to claim 1, characterized in that a control induction loop (4), which is arranged perpendicular to the induction measuring loops (3) on the snow or carpet cover, is preferably provided for adjusting the amplifiers (5) of the induction measuring loops. An embodiment of the arrangement according to claim 1 or 2, characterized in that the control induction loop (4) is located at the edge of the downward slope (1) of the ski jumping rope.