WO2023106743A1 - Frictional force quantification system - Google Patents

Abstract

A frictional force quantification system according to an embodiment accumulates arrows so as to display frictional force at every moment frictional force is generated, and standardizes the magnitude and direction of the frictional force according to a criterion. In addition, the frictional force quantification system sets a frictional force representative value so as to quantify and display major frictional forces of a section supported on the ground during running and various sport movements. In addition, the frictional force quantification system displays the maximum value and average value of measured frictional forces with different colors so that the magnitude and generation position of a frictional force can be more visibly and intuitively identified.

Description

Friction force quantification system

The present disclosure relates to a system for quantifying frictional force, and more specifically, to a system for quantifying and expressing the main frictional force of a section supported on the ground during various sports activities such as running.

Unless otherwise indicated herein, material described in this section is not prior art to the claims in this application, and inclusion in this section is not an admission that it is prior art.

Friction is one of the important factors in sports. Friction is a force that opposes the motion of objects, and occurs on surfaces where two objects come into contact. The magnitude of the frictional force acts opposite to the direction of motion and depends on the surface roughness of the object and the weight of the object. The key to performance is to use the friction force well when an athlete on snow or ice speeds up, stops, or changes direction or turns.

In the case of a skier, heat is generated by friction between the bottom of the ski and the snow. This heat melts the snow and the skis glide well. It is for a similar reason that synthetic plastics are mainly used as ski materials. Synthetic plastic skis have a lower thermal conductivity than metal skis, so they can melt more snow relatively, allowing them to achieve higher speeds.

It is no exaggeration to say that curling, an ice event with a unique combination of stone and broom, is also a game where friction determines victory or defeat. Curling players have to send stones farther or closer depending on their strategy, and in this process, they use brooms to control friction. When the ice is melted by the frictional heat generated by rubbing the ice sheet with a broom, the stone extends farther.

In the case of short track, which is one of the representative ice skating events that compete for speed in 0.001 second increments, it is important for athletes to reduce friction to maintain speed even when going around a curved section. Short track athletes increase the centripetal force, a force opposite to the centrifugal force, by moving their hands in the direction of rotation to overcome the centrifugal force that tries to bounce out of the curve. In addition, a representative example of utilizing frictional force in sports is a skate blade. Skate blades are thin and sharp. The pressure increases as the force applied per contact surface increases or the area to which the force is applied becomes narrower, and as the pressure increases, the ice turns into a water state. When a person's weight is placed on a sharp skate blade, the ice on the contact surface instantly melts into water. The water acts as a lubricant between the skate blade and the ice sheet, reducing friction and increasing speed. Dutch speed skaters mainly use clap skates. As soon as the body moves forward after tiring the ice, the blade separates from the heel of the skate and the skate blade stays on the ice even when the foot is removed, so friction between the blade and the ice occurs. It reduces the load and allows the athlete to maintain speed while relieving physical strain. Utilizing these clap skates, the Netherlands emerged as a speed skating powerhouse. The fingertips are wrapped with smooth epoxy resin to reduce friction even in the gloves worn by short track athletes. Through this, short track athletes wear gloves to prevent falling by leaning their bodies sideways when going around a curved section. In this way, accurate measurement and control of frictional force is very helpful in improving athletic performance, but there is no system and measurement index for accurately measuring frictional force generated during exercise.

The frictional force quantification system according to the embodiment displays the frictional force at every moment when the frictional force is generated by accumulating arrows, and standardizes the size and direction of the frictional force according to a standard. In addition, by setting representative values of frictional force, the main frictional force of the section supported on the ground during running and various sports activities is quantified and expressed.

In addition, the maximum value and the average value of the measured frictional force are displayed in different colors, so that the size and location of the frictional force can be more visually and intuitively grasped.

A system for quantifying frictional force according to an embodiment includes a camera for photographing motion of an analysis object including a player; A reflective marker attached to the foot to generate three-dimensional coordinates; a calculation module for calculating frictional force using the direction and magnitude of the applied force based on the shape of the sole indicated by each reflective marker; An analysis module that analyzes the calculated frictional force according to the location and magnitude of the frictional force; and an output module outputting a display including arrows and colors corresponding to the location and magnitude of the analyzed frictional force. includes

The frictional force quantification system as described above accurately measures the magnitude and location of the frictional force generated on the ground during various sports activities including walking and running, and simplifies the representative value (maximum value, average value) and 8 directions, so that it can be used in various sports activities. The frictional force generated can be quantified.

By quantifying the location and magnitude of the friction force that greatly affects sports motion and performance, the efficiency and performance of sports motion can be improved. can be used to prevent

The effects of the present invention are not limited to the above effects, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the configuration of the invention described in the claims.

1 is a diagram showing the configuration of a system for quantifying frictional force according to an embodiment;

2 is a view showing a camera and a ground reaction force device according to an embodiment;

3 is a diagram showing requirements for calculating frictional force in a system for quantifying frictional force according to an embodiment;

4 is a diagram showing a direction of quantifying frictional force and a final output of quantifying frictional force according to an embodiment;

5 is a view showing an example of frictional force analysis output of a frictional force quantification system according to an embodiment;

6 is a view showing an embodiment of measuring ground reaction force;

7 is a view showing an embodiment in which the landing section and the propulsion section are divided according to the form of the ground reaction force while the feet are supported on the ground.

A system for quantifying frictional force according to an embodiment includes a camera for photographing motion of an analysis object including a player; A reflective marker attached to the foot to generate three-dimensional coordinates; a calculation module for calculating frictional force using the direction and magnitude of the applied force based on the shape of the sole indicated by each reflective marker; An analysis module that analyzes the calculated frictional force according to the location and magnitude of the frictional force; and an output module outputting a display including arrows and colors corresponding to the location and magnitude of the analyzed frictional force. includes

Advantages and features of the present invention, and methods for achieving them, will become clear with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only the present embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs It is provided to fully inform the holder of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals designate like elements throughout the specification.

In describing the embodiments of the present invention, if it is determined that a detailed description of a known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the embodiments of the present invention, which may vary according to the intention or custom of a user or operator. Therefore, the definition should be made based on the contents throughout this specification.

1 is a diagram showing the configuration of a system for quantifying frictional force according to an embodiment.

Referring to FIG. 1 , the frictional force quantification system according to the embodiment includes a camera 10, a reflective marker 100, a ground reaction force 200, a calculation module 300, an analysis module 400, and an output module 500. can be configured to include The term 'module' used in this specification should be interpreted as including software, hardware, or a combination thereof, depending on the context in which the term is used. For example, the software may be machine language, firmware, embedded code, and application software. As another example, the hardware may be a circuit, processor, computer, integrated circuit, integrated circuit core, sensor, micro-electro-mechanical system (MEMS), passive device, or combination thereof.

The camera 100 photographs the movement of an analysis object such as a player whose frictional force is to be measured. As shown in (a) of FIG. 2, the frictional force quantification system according to the embodiment includes two or more infrared cameras and sets a sampling rate of at least 100 Hz to capture motion.

The reflective marker 100 is attached to the foot to generate three-dimensional coordinates and measures the direction and magnitude of the force applied to the attached area. In the embodiment, the reflection marker 100 may be in the form of a sphere having a diameter of 1 cm to 2 cm, and sensing components of force constituting frictional force such as a motion measuring sensor, a muscle force measuring sensor, a speed measuring sensor, and an acceleration measuring sensor. It can be composed of the sensors necessary for

The ground reaction force device 200 senses forces acting on the human body during motion including impact force, propulsion force, and ground reaction force. As shown in (b) of FIG. 2 , the ground reaction force device 200 of the frictional force quantification system according to the embodiment is a device that can measure force applied when the body moves, such as walking or running. For example, in athletics, the force at the start and running time can be precisely measured, and in the baseball game, the pressure when the foot is stepped on during pitching and batting can be measured. In the embodiment, the ground reaction force may be measured by setting the sampling rate of the ground reaction force device 200 to at least 1000 Hz or more. In the embodiment, an infrared camera is installed around where sports motions such as running are performed, and the motion is induced so that the supporting foot is positioned on the ground reaction force. Thereafter, the frictional force is calculated by obtaining the 3D positional coordinates of the six reflective markers shown in FIG. 3 (b) attached to the feet or shoes.

The calculation module 300 calculates the position of the foot with each reflective marker and calculates the frictional force using the direction and magnitude of the applied force based on the shape of the foot. In the embodiment, the calculation module 300 calculates the magnitude of the frictional force as the magnitude of the horizontal force compared to the vertical force pressing the ground vertically. In an embodiment, the calculation module 300 may receive data sensed by the ground reaction force 200 and calculate the frictional force by using a force component according to the direction of the ground reaction force. Components of the force according to the direction of the ground reaction force may include left and right ground reaction force Fx, front and rear ground reaction force Fy, and vertical ground reaction force Fz. The magnitude of the frictional force is calculated as the magnitude of the horizontal ground reaction force relative to the vertical ground reaction force that presses the ground vertically according to Equation 1.

Equation 1

RCOF=Horizontal GRF(Fx, Fy)/Vertical GRF(Fz)

Horizontal GRF=sqrt((Fx) ² +(Fy) ² )

GRF: ground reaction forces,

RCOF: Required coefficient of friction

3 is a diagram showing requirements for calculating frictional force in a system for quantifying frictional force according to an embodiment. In the embodiment, the calculation module 300 calculates the frictional force by calculating the three-dimensional ground reaction force (Fx; left and right ground reaction force, Fy: front and rear ground reaction force, Fz: vertical ground reaction force) shown in FIG. 3 (a) and FIG. ), the direction of the frictional force can be set to the direction of the segmental position of the foot and the direction of the horizontal ground reaction force. Also, in the embodiment, the calculation module 300 may display the magnitude of the applied frictional force as a friction coefficient (horizontal force versus vertical force).

The analysis module 400 analyzes the calculated frictional force according to the applied position and magnitude of the frictional force. For example, as shown in (c) of FIG. 4, the analysis module 400 classifies the direction of the frictional force into 8 directions to generate a frictional force expression section, and the position and size of the maximum frictional force and average frictional force applied to the expression section , analyze the direction. In the embodiment, the expression section may include a landing section for absorbing impact and a propulsion section for applying propulsive force.

The output module 500 outputs a visual display including arrows and colors corresponding to the location and magnitude of the analyzed frictional force. The output module 500 may set a representative value of the frictional force that can be calculated at every moment in the section supported on the ground and display the set representative value. Referring to FIG. 4 , the output module 500 according to the embodiment displays the landing zone D and the tracking distance E along with the friction force quantification index, and also displays a picture F corresponding to the operation at the moment of friction force analysis. can be printed together.

Referring to FIG. 4, the frictional force quantification system according to the embodiment matches the direction of the arrow to the direction of frictional force, the length of the arrow to the magnitude of frictional force, and the starting point of the arrow to the point of force applied to the ground. It is possible to indicate the section supporting the . In addition, the maximum value and the average value of the frictional force may be output in different colors. For example, the maximum value of the frictional force may be output in red and the average value in blue. The meaning of matching the arrow color, character, arrow direction, and length displayed by the output module according to the embodiment shown in FIG. 4 is as follows. (B) PL 1.5 requires (requires) maximum (red) frictional force (friction coefficient) of 1.5 times the vertical force in the PL direction (in the direction of 45 degrees outside the back of the right foot) in the landing section (B), which is the shock absorbing section. is the meaning (B) PL 1.0 requires an average (blue) frictional force (friction coefficient) of 1.0 times the vertical force in the AM-PL direction (45 degrees outward from the back of the right foot) in the landing section (B), which is the shock absorbing section (required) do) can be interpreted as (P) A 2.5 means that a maximum (red) frictional force (friction coefficient) of 2.5 times the vertical force is required (required) in the A direction (front direction based on the right foot) in the propulsion section (P). (P) A 1.5 means that an average (blue) friction force (friction coefficient) of 1.5 times the vertical force is required (required) in the A direction (front direction based on the right foot) in the landing section (P), which is the shock absorbing section. can be interpreted

5 is a diagram showing an example of an output of frictional force analysis of a system for quantifying frictional force according to an embodiment.

Referring to FIG. 5 , the system for quantifying frictional force according to the embodiment segments the photographed motion, extracts the coordinates of the location where the force is applied, maps the extracted coordinates to each point P, and calculates the horizontal ground reaction force at each point. and the vertical ground reaction force can be represented by an arrow.

6 is a diagram showing an embodiment of measuring ground reaction force.

Referring to FIG. 6 , in the embodiment, the ground reaction force may be measured in three dimensions at every moment (0.001 second), and the measured ground reaction force may be converted into a graph over time and displayed.

7 is a view showing an embodiment in which a landing section and a propulsion section are divided according to the form of ground reaction force while the feet are supported on the ground.

Referring to FIG. 7 , the analysis module of the frictional force quantification system according to the embodiment generates a graph of frictional force change over time, and divides the frictional force presenting section into a landing section and a propulsion section in the generated graph and analyzes it. In the embodiment, friction change graphs of various motions including running, jumping, and rotation may be generated and analyzed.

The frictional force quantification system according to the embodiment expresses the frictional force at every moment by accumulating arrows, standardizes the magnitude and direction of the frictional force according to standards, and sets and displays the representative value of the frictional force, thereby determining the magnitude and location of the frictional force generated during sports motion. By accurately measuring and designing sporting goods such as shoes and gloves based on the measurement results, players' performance can be greatly improved.

By accurately measuring the location and magnitude of the frictional force that greatly affects sports motion and performance, it is possible to more accurately analyze the training process and results of athletes. Through this, accurate training feedback can be presented to help improve performance and improve individual players' capabilities.

In addition, by accurately measuring the magnitude and location of the frictional force generated on the ground during various sports activities, including walking and running, and simplifying the representative value (maximum value, average value) and 8 directions, the frictional force generated in various sports activities is quantified. can make it

By quantifying the location and magnitude of the friction force that greatly affects sports motion and performance, the efficiency and performance of sports motion can be improved. can be used to prevent

The disclosed content is only an example, and can be variously modified and implemented by those skilled in the art without departing from the subject matter of the claim claimed in the claims, so the protection scope of the disclosed content is limited to the specific not limited to the examples.

The frictional force quantification system accurately measures the magnitude and location of the frictional force generated on the ground during various sports activities, including walking and running, and simplifies the representative value (maximum value, average value) and 8 directions to determine the frictional force generated in various sports activities. can be quantified.

By quantifying the location and magnitude of the friction force that greatly affects sports motion and performance, the efficiency and performance of sports motion can be improved. can be used to prevent

Claims (7)

In the friction force quantification system, A camera that records the movement of analysis objects including players; A reflective marker attached to the foot to generate three-dimensional coordinates and to measure the direction and magnitude of the applied force; a calculation module that calculates the position of the foot with each reflective marker and calculates the frictional force generated within the sole of the foot in contact with the ground using the direction and magnitude of the applied force; An analysis module that analyzes the calculated frictional force according to the location and magnitude of the frictional force; an output module outputting a display including arrows and colors corresponding to the location and magnitude of the analyzed frictional force; Friction force quantification system comprising a. 2. The system of claim 1, wherein the frictional force quantification system A ground reaction force sensing force acting on the human body during motion including impact force, propulsion force, and ground reaction force; Frictional force quantification system, characterized in that it further comprises. According to claim 1, The calculation module; silver The magnitude of the frictional force is calculated as the magnitude of the horizontal force compared to the vertical force that presses the ground vertically Frictional force quantification system, characterized in that to do. The method of claim 1, further comprising: the output module; silver A friction force quantification system characterized by setting a representative value of frictional force that can be calculated at every moment in a section supported on the ground and displaying the set representative value. The method of claim 1, wherein the analysis module; silver A frictional force quantification system characterized in that the direction of the frictional force is classified into 8 directions to create an expression section, and to analyze the position, magnitude, and direction of the maximum frictional force and average frictional force applied to the expression section. The method of claim 5, wherein the expression section A friction force quantification system comprising a landing section for absorbing shock and a propulsion section for applying propulsive force. According to claim 1, The calculation module; silver A system for quantifying frictional force, characterized in that the magnitude of the applied frictional force is standardized by body weight.

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