EP3555807A1 - A method, an arrangement and a measuring apparatus for measuring sliding of a ski - Google Patents
A method, an arrangement and a measuring apparatus for measuring sliding of a skiInfo
- Publication number
- EP3555807A1 EP3555807A1 EP17828941.9A EP17828941A EP3555807A1 EP 3555807 A1 EP3555807 A1 EP 3555807A1 EP 17828941 A EP17828941 A EP 17828941A EP 3555807 A1 EP3555807 A1 EP 3555807A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- ski
- sliding
- acceleration
- measurement apparatus
- signal processing
- 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.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N19/00—Investigating materials by mechanical methods
- G01N19/02—Measuring coefficient of friction between materials
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
- G06V40/20—Movements or behaviour, e.g. gesture recognition
- G06V40/23—Recognition of whole body movements, e.g. for sport training
Definitions
- the invention relates to a measuring method, a measuring device and a measuring arrangement by which a skier can assess how his or her skis are sliding.
- the invention also relates to a server utilised in the measuring arrangement and also to computer programs in the measuring device and in the server.
- Soles of skies are commonly manufactured from ultra-high molecular polyethylene.
- the under-surface of the ski can be manipulated and optimized for maximal sliding properties. Other features affecting the sliding are different patterning of the under-surface of the skis and utilized waxes.
- the waxing chemicals on the under- surface of the ski may be micro-machined by several techniques for improving sliding of the skis.
- a velocity of the skier can be measured for example by timing gates utilizing a light emitter and receiver, RF emitter and receiver, a Dop- pler measurement system, or a GPS based measurement system.
- the above-mentioned setups can provide information regarding time used to glide a certain distance. This distance is often about 100 m and the distance most often at least has a downward part.
- a test skier normally starts the test by standing still.
- the measurement system detects an acceleration phase and also a sliding phase with higher velocity.
- the test depicted above can only give a rough mean glide velocity value which could differ significantly from a sliding situation in a racing situation.
- an inertial sensor such as an accelerometer or a gyroscope
- Streaming data from the sensor is then collected and partitioned into periods of the skier's periodical movement.
- the data of each period is transformed into a data representation that allows a comparison between consecutive periods.
- the movement period that is due to pushing the poles in the snow contributes to the propulsion of the skier in the direction of movement of the skier.
- the time the poles are in the snow is put in relation to the time of the total period between two consecutive pole pushes. This measurement result gives a measure of how much of the movement period is ac- tually used for propulsing the skier forward.
- WO 2016/174612 is disclosed a measurement system utilized in downhill skiing.
- the depicted measuring method comprises gearing the athlete with a wearable magnetometer sensor unit and 3D acceleration sensor.
- 3D acceleration sensor is configured to obtain speed and a speed drift at a point passage and at the beginning and end of a race.
- EP 3000396 is disclosed a skiing performance measuring method where a 3D accelerometer is utilized. It discusses about deceleration signal when the foot of the skier is pushed against the snow. The depicted velocity signal depicts how quickly velocity v is falling to a value zero (or near zero). From the depicted velocity curve it can be assessed how well the ski suits the skier. Numerous different parameters directly or indirectly affect the ski-snow friction that has to be taken into account when optimizing the glide in cross-country skis. A measurement method to choose a ski pair with the lowest possible friction coefficient is not known, however. Summary of the invention
- the object of the invention is to introduce a new measuring method, measuring device and measuring system, by means of which a sliding index depicting a friction between a ski and the snow can be defined both in cross-country skiing and in downhill skiing.
- the objects of the invention are attained with a measuring method, measuring device, and measuring arrangement, where changes of the velocity of a ski are measured by a 3D acceleration sensor.
- the measurement data discloses consecutively acceleration and deceleration periods that compose one measurement cy- cle that depicts skier's periodical movements in a skiing event. Each measurement cycle discloses an acceleration period and a deceleration period. From momentary acceleration and deceleration measurement is calculated a momentary velocity of the ski. Measurement data of several measurement cycles are then averaged so that the defined graph depicts an averaged velocity graph of the ski under test. In cross-country skiing the sliding index of the tested ski pair can be deduced from negative slope of the averaged velocity graph. In downhill skiing the sliding index of the tested ski pair can be deduced from positive slope of the averaged velocity graph.
- An advantage of the invention is that a cross-country skier or a downhill skier can accomplish sliding tests by himself or herself.
- the measuring method according to the invention defining a sliding index between a ski and the snow in which method:
- a sliding measurement apparatus attached to a ski or an ankle of a skier measures acceleration of the ski during a skiing event
- the sliding measurement apparatus saves the measured acceleration data to a signal processing unit or to a cloud service or to the memory of the sliding meas- urement apparatus - the signal processing unit or cloud service or the sliding measurement apparatus defines from the measured acceleration data a velocity graph and/or an acceleration graph
- the signal processing unit or cloud service or the sliding measurement apparatus defines from the velocity graph or the acceleration graph cycle times of repeated skiing movements
- the signal processing unit or cloud service or the sliding measurement apparatus saves velocity path graphs and/or acceleration path graphs of the defined cycle times
- the ski performance measuring arrangement comprises:
- a sliding measurement apparatus attached to a ski or an ankle or foot or shoe of a skier comprising:
- a signal processing unit or cloud service configured to:
- the sliding measurement apparatus attached to a ski or an ankle comprising:
- - a processor configured to control measuring
- an accelerometer configured to measure accelerations and deceleration of the ski during a skiing event
- - a memory configured to store acceleration, deceleration and processed velocity measurement data
- a transmitter configured to transmit the measured acceleration and deceleration data to a signal processing unit or to a cloud service
- a receiver configured to receive control commands during measuring state, is characterized in that the sliding measurement apparatus is configured to:
- the indicated sliding indexes of the different ski pairs are configured to be utilized in selecting a best sliding ski pair in prevailing weather conditions.
- the computer program according to the invention for defining a glide index of a ski comprising:
- - code means for defining from measurement data an acceleration graph and a velocity graph
- - code means for saving the acceleration path graph of the defined cycle time is characterised in that computer program further comprises:
- - code means for defining a sliding index from the selected angle of gradient that depicts friction between the ski pair and the snow
- - code means for indicating sliding indexes of the different ski pairs to be utilized in selecting a best sliding ski pair in prevailing weather conditions.
- a measuring device is attached to an ankle or a ski of a skier.
- the measuring device has been equipped advantageously with an accelerometer.
- the measuring device may comprise also some other sensors such as GPS, temperature sensor, pressure sensor, and magnetic sensor.
- GPS GPS, temperature sensor, pressure sensor, and magnetic sensor.
- the measuring device may comprise also some other sensors such as GPS, temperature sensor, pressure sensor, and magnetic sensor.
- a momentary velocity of the skis can be calculated from the acceleration and deceleration measurement results.
- the ski-snow friction can be defined from a portion of the velocity graph depicting decreasing velocity of the skis.
- the ski-snow friction can be defined from a portion of the velocity graph depicting increasing velocity of the skis.
- ski-snow friction i.e. the sliding friction
- a sliding index because by it can be expressed by differences in sliding between different ski pairs.
- Figure 1 shows an exemplary skiing event where the skier utilizes sliding index measurement apparatus according to the invention
- Figure 2a shows as an example a first embodiment of the measurement arrangement according to the invention
- Figure 2b shows as an example a second embodiment of the measurement arrangement according to the invention
- Figure 2c shows as an example a third embodiment of the measurement arrangement according to the invention
- Figure 3 shows exemplary main elements of a server utilized in the cloud service
- Figure 4a shows an exemplary velocity graph of a ski
- Figure 4b shows an exemplary acceleration and deceleration graph of several skiing moment cycles
- Figure 4c shows an exemplary averaged acceleration graph of several skiing moment cycles
- Figure 4d shows an exemplary averaged velocity graph wherefrom a glide index slope is defined from a negative velocity gradient
- Figure 4e shows an exemplary averaged velocity graph wherefrom a glide index slope is defined from a positive velocity gradient
- Figure 5 shows as an exemplary flowchart main steps of the method utilized to define a glide index depicting friction between a ski and the snow.
- the embodiments in the following description are given as examples only and someone skilled in the art can carry out the basic idea of the invention also in some other way than what is described in the description. Although the description may refer to a certain embodiment or embodiments in several places, this does not mean that the reference would be directed towards only one described embod- iment or that the described feature would be usable only in one described embodiment. The individual features of two or more embodiments may be combined and new embodiments of the invention may thus be provided.
- a gliding index can be defined for certain point or short length of the skiing track. It can be compared to other gliding indexes defined on the same point or area.
- the gliding index defined can also be compared to gliding indexes defined at different times, let's say in the morning and in the afternoon, at different temperatures, in any different skiing conditions, such as under the direct sun or shadow and differ- ent locations over the skiing track, for example similar flat area or just by comparing uphill and downhill parts of the skiing track.
- Figure 1 shows an exemplary skiing event where a cross-country skier 1 uses an apparatus 3 or 3A that advantageously may be utilized to define a sliding index of the skis 2 that the skier 1 uses.
- the sliding index to be defined is proportional to friction between skis 2 and the snow.
- the sliding index measurement system utilizes velocity, acceleration and in one advantageous embodiment also elevation data from a sliding measurement appa- ratus 3 or 3A attached to a skier's 1 ankle, shoe, or ski 2.
- the sliding measurement apparatus 3 or 3A comprises advantageously at least an accelerometer.
- sensors such as a GPS, temperature sensor, pressure sensor, and magnetic sensor may advantageously be integrated to the sliding measure- ment apparatus 3 or 3A according to the invention.
- skier 1 In a cross-country skiing event the skier 1 increases or maintains his/her skiing speed by making a step or kick effort with the ski 2 against the snow track and/or pushing by ski poles.
- the ski effort movements are naturally cyclic. So the effort movements cause skier's 1 velocity to accelerate and decelerate cyclically.
- the deceleration is caused by many different parameters such as air resistance, friction between the skis 2, and snow and altitude or elevation change.
- the air resistance and altitude variation may in a test situation be kept essentially constant. Therefore the friction between the skis 2 and the snow may advantageously be defined from an averaged velocity graph that is calculated from momentary acceleration and deceleration signals that the sliding measurement apparatus 3 or 3A measures.
- the friction between skis 2 and the snow may be called a sliding index because it relates to a prevailing sliding condition of the skis.
- the sliding measurement apparatus 3 or 3A transmits acceleration, deceleration and elevation measurement results to an external signal processing unit 4 and/or to a cloud service 6 (shown in Figures 2a- 2c).
- the signal processing unit 4 or the cloud service 6 processes from the received measurement data a sliding index according to the invention.
- the signal processing unit 4 is girded onto the waist of the skier 1 .
- the signal processing unit 4 is not carried by the skier 1 .
- the signal processing unit may be in a container or in a car or on the side of the skiing track for example.
- the defined sliding index may be delivered as an audio signal so that the cross-country skier 1 gets the defined sliding index value during skiing for example via an earpiece.
- the audio signal may be transmitted advantageously from the signal processing unit 4 either directly to the earpiece or via the sliding measurement apparatus 3 or 3A.
- the defined sliding index is transmitted to display device on the wrist of the skier, on the ski, or on the ski pole.
- the sliding index measurement system 20A gives the following benefits.
- the invention enables easy and simple comparison for different cross-country ski pairs, skiing waxes, and also skiers.
- the invention also makes it possible that a glide test can be accomplished by a skier 1 himself or herself and no reference tester or supporting person is needed.
- One other benefit is that the glide test can be accomplished without any special technical arrangements such as timing gates or Doppler measurement systems that are commonly utilized in the prior art test arrangements.
- FIG. 2a shows one advantageous ski performance measurement arrangement embodiment 20A according to the invention.
- the ski performance measurement arrangement 20A advantageously comprises a sliding measurement apparatus 3 or 3A, a signal processing unit 4, and an auxiliary display unit 5.
- the sliding measurement apparatus 3 or 3A carried by the skier 1 or assembled on a ski 2 advantageously comprises an energy source such as a battery or an accumulator.
- the electric components in the sliding measurement apparatus 3 or 3A get energy they need for their function from the battery.
- the accelerometer is advantageously a 3D accelerometer.
- Measurement data from the 3D accelerometer is processed in a measuring event in the processor of the sliding measurement apparatus 3.
- the processor is connected also to a memory.
- the memory is used for storing the computer programs needed in processing the acceleration and deceleration measurement data. All the measurement results during testing are advantageously stored at least temporarily in the memory.
- the processor is also connected to data transfer components such as a transmit- ter and a receiver. With the aid of these data transfer components a data transfer connection may be established to a signal processing unit 4 or to a cloud service 6 belonging to the ski performance measurement arrangement 20A.
- the data transfer components advantageously support at least one data transfer method. Some advantageous transfer methods usable in data transfer are infrared technology (IR), Bluetooth ® technology, ZigBee ® technology, UWB technology, WLAN technology, and various time or code division data transfer technologies used in common cellular networks.
- Acceleration and deceleration measurement data stored in the memory of the sliding measurement apparatus 3 are transferred via the transmitter and the wireless data transfer connection to the signal processing unit 4 and/or to the cloud service 6 that are capable of defining a sliding index according to the invention from the measurement data.
- the signal processing unit 4 may advantageously be a smart phone, tablet or laptop computer.
- the basic electronic elements such as a processor, memory, receiver, transmitter, user interface and battery and their mutual electrical connections in the smart phone, tablet or laptop computer are well known.
- the signal processing unit 4 may transmit via the transmitter control commands to the sliding measurement apparatus 3 or 3A and receive measurement data from the sliding measurement apparatus 3 or 3A.
- the processor of the signal processing unit 4 may advantageously define the sliding index from the received measurement data.
- the signal processing unit 4 comprises a display on which the defined sliding index may be shown.
- the signal processing unit 4 may receive the defined sliding index from the cloud service 6.
- the defined sliding index according to the invention from the signal processing unit 4 or from the cloud service 6 may advantageously be shown on an auxiliary display unit 5 when the signal processing unit 4 has transmitted it to the auxiliary display unit 5.
- the display unit 5 comprises advantageously a processor, memory, receiver, battery, and display.
- the display unit 5 advantageously receives the defined sliding index according to the invention from the signal processing unit 4 or from the cloud service 6.
- the sliding measurement apparatus 3 may advantageously comprise also other measuring sensors than the above-mentioned 3D accelerometer.
- the other sensors can be either a part of the sliding measurement apparatus 3 or 3A or they may be separate sensors on a skier's 1 body or on the ski 2.
- the measuring data from these sensors is advantageously transferred to the sliding measurement apparatus 3 either via a wired or a wireless data transfer connection.
- sensors measuring physiological properties of the skier 1 may also be included in the ski performance measurement arrangement 20A according to the invention (not shown in Figure 2a). Examples of such sensors are a sensor measuring body temperature, a sensor measuring breathing functions, a sensor measuring muscle movements, a sensor monitoring heart rate.
- the signal processing unit 4 or cloud service 6 may advantageously process also the data from these auxiliary measuring sensors and store it for later use. In one advantageous embodiment at least some of the other measured parameters may be shown for example on the auxiliary display unit 5.
- Figure 2b shows another advantageous ski performance measurement arrange- ment embodiment 20B according to the invention.
- the second embodiment differs from the first embodiment in that the display unit 5 in Figure 2a has been embedded into the signal processing unit 4A.
- Figure 2c shows a third advantageous ski performance measurement arrange- ment embodiment 20C according to the invention.
- functional elements from the signal processing unit 4 and display unit 5 of Figure 2a have been embedded into the sliding measurement apparatus 3B.
- the sliding index according to the invention is processed from the measurement results that are stored in the memory of the sliding measurement appa- ratus 3B.
- the apparatus does not have a display. But it may use another auxiliary display or mobile device or computer with a display which is has a connection to a cloud service.
- the sliding measurement apparatus 3B comprises transmitter and receiver that are capable to receive command messages and to transmit measurement results via one known cellular communications system such as 2G, 3G, 4G, 5G network, Bluetooth, Wi-Fi, or any known RF radio link.
- one known cellular communications system such as 2G, 3G, 4G, 5G network, Bluetooth, Wi-Fi, or any known RF radio link.
- the sliding measurement apparatus 3B also comprises a user interface and dis- play for receiving instructions and displaying test results.
- FIG. 3 shows the functional main parts of an exemplary server 60 that is utilized in the cloud service 6.
- the server 60 comprises a processor or processor means
- a data storing arrangement 62 such as a memory unit or memory means, wherein computer-readable information or programs or user information can be stored, has been connected to the processor means.
- the memory means
- the server 60 also comprises an interface element 64 which comprises an input or input means 66 for receiving measurement data via a data communications network from the sliding measurement apparatus 3 or 3A. The measurement information received with the input means 66 is transferred to be processed by the processor means 61 of the server 60.
- the interface element 64 of the server 60 also comprises an output or output means 65, with which sliding index information is transferred from the processing means of the server 60 via a telecommunication network either to the sliding measurement apparatus 3, 3A or to a signal processing unit 4, 4A.
- the server 60 advantageously also comprises a user interface 63, which compris- es means for receiving information from the signal processing unit 4, 4A.
- the user interface 63 may comprise a keyboard, a touch screen, a microphone, and a speaker.
- the processor means 61 , the memory means 62, the interface element 64, and the user interface 63 are electrically joined together to systematically execute received and/or stored data in accordance with predetermined and essentially preprogrammed operational sequences.
- Such operational sequences include the operations and operational sequences described in connection with Figure 5 and utilised in implementing the sliding index determination according to the invention.
- the detailed implementation of the logical units of the server in Figure 3 is prior art to one skilled in the art.
- Figure 4a shows an exemplary velocity graph 40 of a cross-country skier 1 of Figure 1 . It can be seen that the velocity of the skier changes cyclically.
- cycle time period measured from one maximum velocity value to the next maximum velocity value is marked by a reference number 41 .
- cycle time periods 41 between consecutive velocity maximums may essentially have a constant value.
- Figure 4b shows an exemplary acceleration and deceleration graph 42 of a crosscountry skier 1 that corresponds to the velocity behaviour that has been shown in Figure 4a.
- the shown measurement data discloses consecutively acceleration (having a positive slope in Figure 4b) and deceleration periods (having a negative slope in Figure 4b).
- the cycle time periods depict skier's periodical movements in a skiing event.
- Each time period cycle 41 discloses an acceleration period and a deceleration period.
- the shown acceleration and deceleration values in Figure 4b are actually meas- ured by the sliding measurement apparatus 3, 3A or 3B according to the invention.
- Some exemplary portions of the acceleration path graph 42 are defined by letters a-b, c-d, and e-f and three exemplary deceleration phases of three consecutive cycles 41 are depicted. From the actual momentary acceleration and deceleration values is then calculated a momentary velocity 40 of the skier that is shown in Figure 4a.
- Figure 4c shows as an example how the acceleration and deceleration data of several, for example 2-10, measurement cycles 41 can be combined and then av- eraged so that the defined graph depicts an averaged acceleration path graph 43 of the ski pair under test.
- the averaged acceleration path graph can be calculated for example by using periods a-c, c-e, or alternatively periods b-d and d-f of Figure 4b.
- periods starting from the maximum acceleration time point are utilized.
- the second alternative cyclic time periods starting from the zero crossing time point are utilized.
- Figure 4d shows as an example how velocity data of several time period cycles 41 can be combined and then averaged so that the defined graph 40A depicts an averaged velocity of the ski pair under test.
- Figure 4d discloses also defined averaged acceleration graph 43A. A zero crossing point 45 of the averaged acceleration graph 43A is shown.
- the sliding index of the tested ski pair can be deduced from a negative slope of the averaged velocity graph 40A advantageously as follows.
- the zero crossing point 45 on the averaged acceleration path graph 43A can be used as a starting point to calculate the velocity path graph 40A and a gradient 44 of the averaged velocity graph 40A can be drawn related to that point. It is obvious that any other timing points in the averaged acceleration path graph 43A may be used for calculating the corresponding velocity path graph.
- the angle of the defined gradient 44 on the averaged velocity path graph 40A depends on the deceleration values after point 45 on the averaged acceleration path graph 43A.
- the deceleration values around the above-mentioned zero crossing point 45 depend on the friction between the ski pair and the snow. So from the angle of the gradient 44 defined from the averaged velocity path graph 40A can be defined a sliding index that depends on the ski-snow friction of the tested ski pair.
- a sliding index can be defined from the gradient 44 as fol- lows. If the gradient angle between a horizontal axis x-axis and gradient with - sign due a clockwise direction from the horizontal axis is 0 degrees, then the sliding index is advantageously 100. If the gradient angle is -84 degrees, then the sliding index is advantageously 1 . The values of gradient angles between 0 - -84 degrees can be linearly or non-linearly pointed to sliding index that is between 100 - 1 .
- Figure 4e shows as an example how from measurement data of several measurement cycles 41 measured in downhill skiing the sliding index of the tested ski pair can be deduced from positive slope of the averaged velocity graph 43B.
- Figure 4e discloses also defined averaged acceleration graph 43B.
- a zero crossing point 46 is shown in an acceleration portion of the averaged acceleration graph 43B.
- the sliding index of the tested ski pair can be deduced from a positive slope of the averaged velocity graph 40B advantageously as follows.
- the zero crossing point 46 on the averaged acceleration path graph 43B can be used as a starting point to calculate the velocity path graph 40B and a gradient 47 of the averaged velocity graph 40B can be drawn related to that point. It is obvious that any other timing points in the averaged acceleration path graph 43B may be used for calculating the corresponding velocity path graph.
- the angle of the defined gradient 47 on the averaged velocity path graph 40B de- pends on the acceleration values after point 46 on the averaged acceleration path graph 43B.
- the acceleration values after the above-mentioned zero crossing point 46 depend on friction between the ski pair and the snow and possible slope of the downhill and its acceleration effect on the skis. So the angle of the gradient 47 defined from the averaged velocity path graph 40A can be utilized as one parameter when a sliding index is defined.
- a sliding index can be defined from the gradient 47 as follows. If the gradient angle between a horizontal axis x-axis and gradient with +sign due a anticlockwise direction from the horizontal axis is 0 degrees, then the sliding index is advantageously 1 . If the gradient angle is 84 degrees, then the sliding index is advantageously 100. The values of gradient angles between 0 - +84 degrees can be linearly or non-linearly pointed to sliding index that is between 1 and 100. It is possible to use any kind of suitable scaling and calculation tables to define a practical sliding index.
- Figure 5 shows as an exemplary flowchart the functional main steps of the method of defining a sliding index of a ski pair.
- step 50 the skier starts the skiing test.
- the skier can give a starting command to the sliding measurement apparatus 3, 3A or 3B in several ways.
- One alternative is to give the test starting command by utilizing the user interface of the signal processing unit 4.
- the signal processing unit 4 transmits the starting command ad- vantageously via a wireless connection to the sliding measurement apparatus 3 or 3A.
- Another alternative is to activate the sliding measurement apparatus 3B by utilizing the user interface embedded into the sliding measurement apparatus 3B.
- an accelerometer measures continuously momentary acceleration or deceleration values.
- the measured acceleration or deceleration values are advantageously transmitted either to the signal processing unit 4 or to the cloud service 6 for further processing.
- Measurement data transmission may be either real time or the measurement data may be transmitted after the ski test.
- the measured acceleration and deceleration values are processed directly in the sliding measurement apparatus 3B.
- the defined measurement result may advantageously be transmitted to the cloud service 6 after a ski pair test.
- a momentary velocity value of the skier is integrated from the momentary acceleration and deceleration values that have been measured in the test period underway.
- a velocity path graph 40 shown in Figure 4a may be defined.
- cycle time periods are defined from velocity path graph 40.
- step 53 one raw cycle time period at a time is selected.
- a cycle time period which deviates more than a predetermined variation threshold, advantageously may be discarded.
- step 54 the velocity cycle path graph data of an accepted cycle time period is saved.
- the velocity path graph data may be saved in the memory of the signal processing unit 4, in a cloud service 6 or in the memory of the sliding measurement apparatus 3, 3A or 3B.
- the measured acceleration and deceleration path graph of the accepted cycle time period may be saved.
- step 55 it is checked if all measured cycle time periods are either stored in the memory or have been discarded in step 53. If the result of the check 55 is that there are unverified cycle time periods left, the process returns to step 53. If the result of the check 55 is that all cycle time periods have been verified, the process proceeds to step 56.
- step 56 an averaged velocity path graph 40A or 40B is calculated.
- an averaged acceleration path graph 43A or 43B is calculated.
- the calculated path graphs are then saved in the memory of the signal processing unit 4, in the cloud service 6 or in the memory of the sliding measurement apparatus 3B.
- step 57 is first defined a gradient 44 or 47 either on the decreasing velocity slope portion of the velocity path graph 40A or on the increasing velocity slope portion of the velocity path graph 40B.
- an angle of the defined gradient 44 or 47 is defined.
- step 58 the defined angle of gradient is converted to a sliding index according to the invention.
- the sliding index definition process ends in step 59 where the defined sliding in- dex of the tested ski pair is saved in the memory of the signal processing unit 4, in the cloud service 6 or in the memory of the sliding measurement apparatus 3B.
- the skier can compare the sliding indexes of the different ski pairs and select the best sliding ski pair for that particular weather and for the snow circumstances.
- All the process steps presented above in Figures 5 can be implemented with computer program commands, which are executed in a suitable special-purpose or general-purpose processor.
- the computer program commands can be stored in a computer-readable media, such as a data disk or a memory, from where the processor can retrieve said computer program commands and implement them.
- the references to computer-readable media can for example also contain special components, such as programmable USB Flash memories, logic arrays (FPLA), application-specific integrated circuits (ASIC), and signal processors (DSP).
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Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FI20165975A FI127357B (en) | 2016-12-16 | 2016-12-16 | Method, arrangement and measuring device for measuring ski slip |
PCT/FI2017/050877 WO2018109269A1 (en) | 2016-12-16 | 2017-12-12 | A method, an arrangement and a measuring apparatus for measuring sliding of a ski |
Publications (1)
Publication Number | Publication Date |
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EP3555807A1 true EP3555807A1 (en) | 2019-10-23 |
Family
ID=60957334
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP17828941.9A Withdrawn EP3555807A1 (en) | 2016-12-16 | 2017-12-12 | A method, an arrangement and a measuring apparatus for measuring sliding of a ski |
Country Status (3)
Country | Link |
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EP (1) | EP3555807A1 (en) |
FI (1) | FI127357B (en) |
WO (1) | WO2018109269A1 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN114589693B (en) * | 2022-03-02 | 2024-07-09 | 东北大学 | Robot for measuring translational friction coefficient between snowboard and snowboard surface |
SE2230426A1 (en) * | 2022-12-19 | 2024-06-20 | Anders Mannelqvist | Roller ski for measuring the added power and force of the roller skier |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE537845C2 (en) | 2013-07-18 | 2015-11-03 | Wememove Ab | Method and system for determining performance indicators for periodic movements |
DE102014014017A1 (en) | 2014-09-26 | 2016-03-31 | HS Innovation GmbH | Portable motion analysis system |
US20180292429A1 (en) | 2015-04-28 | 2018-10-11 | Ecole Polytechnique Federale De Lausanne (Epfl) | High Precision Trajectory and Speed Sensor and Measuring Method |
-
2016
- 2016-12-16 FI FI20165975A patent/FI127357B/en not_active IP Right Cessation
-
2017
- 2017-12-12 WO PCT/FI2017/050877 patent/WO2018109269A1/en unknown
- 2017-12-12 EP EP17828941.9A patent/EP3555807A1/en not_active Withdrawn
Also Published As
Publication number | Publication date |
---|---|
WO2018109269A1 (en) | 2018-06-21 |
FI127357B (en) | 2018-04-13 |
FI20165975A (en) | 2018-04-13 |
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