JP6767009B2 - Motion analysis system - Google Patents

Description

The present invention relates to a motion analysis system capable of detecting the load and the position of a foot of a subject exercising in a wide place such as a stadium.

Generally, when analyzing the load of the foot applied when the subject is running and its position, a method of having the subject exercise on a belt orbiting the force plate and detecting the load applied from the subject and the position of the foot. Is used (Patent Document 1, Patent Document 2, etc.).

Such an analysis device is configured by providing a force plate having a plurality of load cells, an endless belt that circulates on the force plate, and the like, and moves the subject on the endless belt that circulates on the left and right force plates. By asking them to do so, it is possible to detect the load and the position of the foot. By using such an analysis device, it is possible to analyze the exercise state by detecting the load applied to the subject's foot and the position of the foot by having the subject exercise on the belt in a narrow indoor space or the like. There are merits.

However, when using such an analysis device to exercise on the force plate, the exercise is inevitably performed in a narrow indoor space, so that the actual running and exercise state on the land track will change. It will be.

Therefore, it is conceivable to spread a plurality of force plates on an actual land track and have the subject exercise on these force plates to analyze the load applied during exercise and the position of the foot. However, when multiple force plates are laid out in this way, it is necessary to instantly detect the load from all the force plates and calculate the position of the foot, etc., and the adjacent force plates and the force plates Since the boundary part may be trampled, it is necessary to detect the load and calculate the position of the foot from the combination of these two force plates. Therefore, there is a problem that a computer having a high-precision CPU is required.

Japanese Unexamined Patent Publication No. 2016-34577 Japanese Unexamined Patent Publication No. 2015-160018

Therefore, the present invention has been made by paying attention to the above-mentioned problems, and by having a subject exercise on a force plate spread over a plurality of units, it is possible to detect the load applied during the exercise, the position of the foot, and the like. At the same time, it is an object of the present invention to provide a motion analysis system capable of quickly calculating the load and the position of the foot by reducing the amount of calculation.

That is, in order to solve the above problems, the present invention lays a plurality of force plates having load cells along the traveling direction of the subject, and the load of the subject traveling forward on the laid multiple force plates In the motion analysis system for detecting the position, among the plurality of force plates, a tread plate detecting means for detecting the force plate pressed by the subject and a force plate determined to be treaded by the tread plate detecting means. And the output means that outputs the output value of the load cell only from the adjacent force plate in front of the force plate in the traveling direction, and the foot position calculation that calculates the position of the subject's foot from the value output by the output means. It is provided with means and display means for displaying the foot position calculated by the foot position calculation means and the output value of the load cell.

With this configuration, the load etc. is output only from the pressed force plate and the force plate adjacent to it, so that the load and foot position can be calculated quickly based on a small amount of data. Become.

Further, in such an invention, when it is determined that the boundary between the two force plates is pressed at the same time, the output values of all the load cells of the two force plates pressed at the same time are output, and the pressure plates are output. It is determined that the force plate in front of the subject is pressed by the detection means in the direction of travel of the subject .

With this configuration, even when the subject steps on the boundary part of the force plate, the load can be detected from the load cells of the two force plates and the position of the foot can be calculated, and the subject can calculate the position of the foot. You will be able to exercise without being aware of the boundary of the force plate.

Further, the output from the force plate determined to have been treaded by the tread plate detecting means is output by changing the voltage value so as to be different from the output from other force plates, so that the output depends on the magnitude of the voltage value. Determine if the force plate has been treaded.

With this configuration, it becomes possible to determine which force plate is pressed by the magnitude of the voltage value.

According to the present invention, a plurality of force plates having load cells are laid along the traveling direction of the subject, and the load and position of the subject traveling forward on the laid multiple force plates are detected. In the motion analysis system, among the plurality of force plates, the tread plate detecting means for detecting the force plate pressed by the subject, the force plate determined to be treaded by the tread plate detecting means, and the running of the force plate . An output means that outputs the output value of the load cell only from the adjacent force plate in front of the direction, a foot position calculation means that calculates the position of the subject's foot from the value output by the output means, and the foot position calculation. Since the foot position calculated by the means and the display means for displaying the output value of the load cell are provided, the load and the like are output only from the pressed force plate and the force plate adjacent thereto. This makes it possible to quickly calculate the load, the position of the foot, etc. based on a small amount of data.

Overall schematic of the motion analysis system according to the embodiment of the present invention Functional block diagram of the motion analysis system in the same form The figure which shows the method of calculating the position of the foot in the anteroposterior direction of the force plate in the same form. The figure which shows the method of calculating the position of the foot in the left-right direction of the force plate in the same form. The figure which shows the method of calculating the position of a foot when two force plates in the same form are pressed at the same time. The figure which shows the flowchart in the same form

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the motion analysis system 1 of this embodiment uses a plurality of force plates 2 laid on a track of an athletic field and a load cell 21 provided on the force plates 2 of a subject. It is designed so that the load, the position of the foot, etc. can be calculated and displayed on the personal computer 5. Characteristically, when the force plate 2 is stepped on, the force plate 2 or the force plate 2 adjacent thereto can be displayed. Only the load and the like are output to the control unit 4, so that the position of the foot and the like can be calculated with a small amount of calculation. Hereinafter, the motion analysis system 1 according to the embodiment of the present invention will be described.

First, as shown in FIG. 1, the force plates 2 constituting the motion analysis system 1 are two upper and lower metal plates having a square or rectangular shape (the upper metal plate is indicated by a wavy line) and the two. It is configured to have load cells 21 provided near the four corners between the metal plates, and these load cells 21 can be used to detect a load or the like. Here, it is assumed that a total of four force plates 2 are provided at the positions of both hands and feet at the starting point, and 50 force plates 2 are provided along the traveling direction. The load cell 21 of each of these force plates 2 is configured so that when strain is generated by the load, the load on the XYZ axes can be detected by the voltage value that changes due to the strain. As the XYZ axis directions, the traveling direction is the Y axis (horizontal direction in FIG. 1), the direction orthogonal to this in the horizontal plane is the X axis, and the vertical direction is the Z axis. Then, the voltage value output in this way is amplified by the amplifier, and after being A / D converted by the A / D conversion unit 22 in FIG. 2, the component force calculation unit 23 can calculate the 6 component force.

When the component force calculation unit 23 calculates the 6 component force, the loads Fx to Fz and Mx to Mz for each force plate 2 are calculated based on the values output from each load cell 21. First, when calculating the load in the XYZ-axis directions, the loads Fz1 to Fz4 of the four load cells 21 are added in the Z-axis direction, and in the Y-axis direction, the loads Fy1 + Fy4 of the two front and rear load cells 21 arranged along the Y-axis direction. , Fy2 + Fy3 are calculated, and for the X-axis direction, the loads Fx1 + Fx2 and Fx3 + Fx4 of the two load cells 21 arranged in the X-axis direction are calculated. On the other hand, for the moment, the moments Mx, My, and Mz around each axis are calculated with reference to the center of the force plate 2. When calculating this moment, the distance from the center of the force plate 2 to the load cell 21 along the lateral direction (X-axis direction) is a, and the distance to the load cell 21 along the traveling direction (Y-axis direction) is b. In this case, it is calculated using the following equation 1. The final argument numbers "1 to 4" in Fx1 to Fz4 and Mx1 to Mz4 indicate the load and the moment in the numbers in parentheses shown in the load cell 21 in FIG.

<Equation 1>
Mx = b × (Fz1 + Fz2 + Fz3 + Fz4)
My = a × (Fz1 + Fz2 + Fz3 + Fz4)
Mz = b × (Fx12 + Fx34) + a × (Fy14 + Fy23)
a: Distance from the center of the force plate 2 to the load cell 21 in the X-axis direction
b: Distance from the center of the force plate 2 to the load cell 21 in the Y-axis direction

Then, the 6-component force calculated in this way is D / A converted by the D / A conversion unit 24 and output to the centralized relay board 3. Since this centralized relay board 3 is often provided at a position separated from the force plate 2 by several tens of meters to 100 meters or more, if a voltage value is output between them, it will be affected by attenuation and noise on the way. , Inaccurate data will be output. Therefore, here, the current conversion unit 25 is used to convert the voltage value for 6 channels, which is a 6-component force signal output as a voltage value, into a current value, and centralized relay as a signal with little influence of attenuation and noise. Output to board 3. When the cables are output from each force plate 2 toward the centralized relay board 3, a relay station is provided in the middle in order to reduce the number of cables, and the current value is output from there to the centralized relay board 3. It may be.

In the centralized relay board 3, the current value outputs for 6 channels of all the force plates 2 are A / D converted by the A / D converter 31 to obtain a digital signal. In this embodiment, since four force plates 2 are provided at the starting point and 50 force plates 2 are provided along the traveling direction, digital data of 6 × (4 + 50) = 324 can be obtained. Will be obtained.

The tread plate detecting means 32 compares the Fz of the 50 force plates 2 along the traveling direction with the reference value (for example, 50N) in order from the first unit, and first detects that the reference value is exceeded. The force plate 2 is determined to be the "pressed force plate 2". That is, when two force plates 2 are pressed at the same time, it is determined that the force plate 2 having the lower number is pressed. On the other hand, if all the force plates 2 do not exceed the reference value, the previous judgment is inherited, and if all the force plates 2 do not exceed the reference value for a certain period of time (for example, about 5 seconds). It is determined that the first force plate 2 is stepped on.

The output means 33 transmits signals such as a load and a moment, and a number of the pressed force plate 2 only from the force plate 2 determined to be pressed by the tread plate detecting means 32 and the force plate 2 adjacent to the front of the force plate 2. Output. When the number of the force plate 2 is output as a signal, when the Nth force plate 2 is pressed, a voltage value of "-10 + 0.4 × N (V)" is output to 1ch, and each force plate 2 is output. It is possible to determine which force plate 2 is pressed by the voltage value that changes each time. On the other hand, the six values of the load and moment of the Nth force plate 2 are output to channels 2 to 7, and the six values of the load and moment of the (N + 1) th force plate 2 are output to the following channels 8 to 13. Is output. When the last force plate 2 is pressed (when N = 50), 8 to 13 channels are set to "0V". Further, on channels 14 to 37, six values of the load and the moment detected from the four force plates 2 at the starting point are output to the control unit 4 as analog data.

Then, in the control unit 4, the ± 10V voltage value input of 1ch to 37ch from the centralized relay board 3 is A / D converted by the A / D conversion unit 41, and digital data for 37ch is obtained. As a result, the digital data of 324 channels is originally reduced to 37 channels, and the processed data can be significantly reduced. Then, the data of the first channel whose voltage value changes for each number of the pressed force plate 2 is inversely calculated to detect the number of the pressed force plate 2, and the values of 2 to 13 channels are the values of which force plate 2. Judge if it is.

Then, the foot position calculating means 42 calculates the COP (Center Of Pressure), which is the treading position of the pressed force plate 2, by using the value output in this way. When calculating this COP, the output is performed at the coordinates with the start point as the origin.

When calculating this COP, the coordinate position LF and LR of the foot in the front-rear direction are calculated from the equilibrium equation <Equation 2> of the load applied to the load cell 21 in the pressed force plate 2 and the moment in the front-rear direction. This equilibrium formula shows the equilibrium of moments centered on the position of the foot in FIG.

<Equation 2>
PF x LF = PB x LB
L = LF + LB (= 2b)
PF: Total load value in the Z-axis direction of the two front load cells 21 PB: Total load value in the Z-axis direction of the two rear load cells 21 LF: Distance from the foot position to the front load cell 21 LB: Foot position Distance from to the rear load cell 21 L: Distance of the front and rear load cells 21

Of these values, PF and PB are output values from the load cell 21 as shown in FIG. 3, and L is known as the distance between the front and rear load cells 21. Therefore, from these values, the respective force plates are used. It is possible to calculate the position LF and LB of the foot in the front-back direction in 2. Then, based on the number of the force plate 2, the length up to the force plate 2 up to the previous point is added to calculate the distance from the start point.

On the other hand, regarding the position of the foot in the left-right direction on the force plate 2, the coordinate position WR, WL, etc. of the foot in the left-right direction can be obtained from the balance equation <Equation 3> of the load applied to the load cell 21 in the force plate 2 and the moment in the left-right direction. Can be calculated. This equilibrium formula shows the equilibrium of moments centered on the position of the foot in FIG.

<Equation 3>
PL x WL = PR x WR
W = WL + WR (= 2a)
PR: Total load value in the Z-axis direction of the two load cells 21 on the right side PL: Total load value in the Z-axis direction of the two load cells 21 on the left side WR: Distance from the foot position to the load cell 21 on the right side WL: Position of the foot Distance from to the left load cell 21 W: Distance between the left and right load cells 21

Of these values, PR and PL are output values from the load cell 21 as shown in FIG. 4, and W is known as the distance between the left and right load cells 21. Therefore, from these values, each force plate is used. It is possible to calculate the position WR, WL, etc. of the foot in the left-right direction in 2.

On the other hand, as shown in FIG. 5, when the boundary between the front and rear force plates 2 is pressed at the same time, the load is output from the two force plates 2 at the same time, but the pressed two forces are pressed. The foot position (COP) is calculated by regarding the plate 2 as one force plate 2. At this time, the foot position LF and LB in the front-rear direction can be calculated from the moment balance equation <Equation 4>.

<Equation 4>
PFF x LFF + PFR x LFR = PRF x LRF + PRR x LRR
PFF: Total load value in the Z-axis direction of the two front load cells 21 in the front force plate 2 PFR: Total load value in the Z-axis direction of the two rear load cells 21 in the front force plate 2 PRF: Two front in the rear force plate 2 Total load value in the Z-axis direction of the load cell 21 PRR: Total load value in the Z-axis direction of the two rear load cells 21 in the rear force plate 2

Then, the distance from the starting point is calculated by considering the length of the force plate 2 up to just before the pressed force plate 2.

On the other hand, the position of the foot in the left-right direction in FIG. 5 can be similarly obtained by the moment balance equation. When the boundary portion of the left and right force plates 2 is stepped on, the position of the foot is calculated using the following <Equation 5>.

<Equation 5>
PR x WR = PL x WL
PR: Total load value in the Z-axis direction of the four load cells 21 on the right side of the front and rear force plates 2 PL: Total load value in the Z-axis direction of the four load cells 21 on the left side of the front and rear force plates 2

Then, the COP calculated in this way, the values of the loads Fx, Fy, Fz of the pressed force plate 2 and the moments Mx, My, Mz of the pressed force plate 2 are transferred to the personal computer 5 via the USB cable. Output and output to the display using the display means 51.

Next, an operation example of the motion analysis system 1 configured in this way will be described with reference to the flowchart of FIG.

First, when the subject travels from the starting point and the first force plate 2 is pressed, the load is output as a voltage value from the load cell 21 of the first force plate 2. Then, this load value is amplified (step S1) and converted into a digital signal by the A / D converter 22 (step S2). Then, the component force calculation unit 23 is used to calculate the 6 component forces such as the load and the moment (step S3). At this time, as the moment, the moment centered on the XYZ axes centered on the center position of the force plate 2 is calculated. Then, the value is converted into analog data again by the D / A conversion unit 24 (step S4), converted into a current value by the current conversion unit 25 (step S5), and then 6ch data of Fx to Fz and Mx to Mz. Is output toward the centralized relay board 3 (step S6).

On the other hand, in the centralized relay board 3, it is determined which force plate 2 is stepped on by using the reference value (step S7). Here, since the load exceeding the reference value is detected by the first force plate 2, it is determined that "N = the first force plate 2 is stepped on" and the output means 33 is used. The load and moment of the first force plate 2 and the second force plate 2 adjacent to the front of the first force plate 2 are output. As the output voltage value, a voltage value corresponding to the number of the force plate 2 such as "-10 + 0.4 x 1 (V)" is output here (step S8), and the voltage is pressed by this voltage value. The number of the force plate 2 can be determined later.

Then, the control unit 4 A / D-converts this output value (step S9), and the foot position calculating means 42 calculates the COP (step S10). Then, the foot position calculation means 42 calculates the position of the foot at the coordinates with respect to the start point using the above equations 2 to 3, and the above-mentioned load, moment, COP, etc. are displayed on the display means 51 of the personal computer 5. Display and output (step S11).

Similarly, when the subject steps on the Nth force plate 2, the load is output as a voltage value from the load cell 21 of the Nth force plate 2 in the same manner, and this is amplified (step S1). ), Converted to a digital signal by the A / D conversion unit 22 (step S2). Then, the load and moment are calculated using the component force calculation unit 23 (step S3), and the values are converted into analog data again by the D / A conversion unit 24 (step S4). Then, after being converted into a current value by the current conversion unit 25 (step S5), it is output to the centralized relay board 3 as 6ch data of Fx to Fz and Mx to Mz (step S6).

Further, in the centralized relay board 3, it is determined which force plate 2 is stepped on by comparing with the reference value. Here, since the load exceeding the reference value is detected by the Nth force plate 2, the Nth force plate 2 and the (N + 1) th force plate 2 are detected via the output means 33. Outputs loads and moments. The output voltage value is a voltage value corresponding to the number of the force plate 2 such as "-10 + 0.4 x N (V)" (step S8), and the force plate 2 pressed by this voltage value is output. To be able to determine the number of.

Then, the control unit 4 A / D-converts this output value (step S9), and the foot position calculating means 42 calculates the COP (step S10). Then, the foot position calculating means 42 calculates the position of the foot at the coordinates with respect to the start point using the above equations 2 to 3, and when the boundary portion of the force plate 2 is trampled, the equation The position of the foot is calculated using the formulas 4 to 5, and the above-mentioned load, moment, COP, etc. are displayed and output to the display means 51 of the personal computer 5 (step S11).

Hereinafter, the COP is calculated by outputting the load only from the force plate 2 pressed in the same manner and the force plate 2 adjacent thereto.

As described above, according to the above embodiment, a plurality of force plates 2 having the load cells 21 are laid along the traveling direction of the subject, and the load of the subject traveling forward on the laid plurality of force plates 2. in the motion analysis system 1 to detect the or position, of the plurality of force plate 2, the pedaling pressure plate detecting means 32 for detecting a force plate 2 by a subject pedaling pressure is treading by the treading plate detecting means 32 The output means 33 that outputs the output value of the load cell 21 only from the force plate 2 determined to have been used and the adjacent force plate 2 in front of the force plate 2 in the traveling direction, and the value output by the output means 33. Since the foot position calculation means 42 for calculating the foot position of the subject and the display means 51 for displaying the foot position calculated by the foot position calculation means 42 and the output value of the load cell 21 are provided. It will be possible to quickly calculate the load, foot position, etc. based on a small amount of data.

Further, when it is determined that a plurality of force plates 2 are pressed at the same time, the position of the subject's foot is calculated using the output values of all the load cells 21 of the plurality of pressed force plates 2. Therefore, even when the subject steps on the boundary portion of the force plate 2, the load can be detected from the load cells 21 of the two force plates 2 to calculate the position of the foot and the like, and the force plate 2 can be calculated. You will be able to drive without being aware of the boundary part.

Further, a current conversion unit that converts a voltage value, which is an output value from the load cell 21, into a current value is provided, and the current conversion unit 25 converts the output of the load cell 21 into a current value on the tread plate detecting means 32 side. Since the output is made, even if the distance between the force plate 2 and the computer becomes long, by outputting the signal with the current value, the influence of noise and attenuation is reduced and an accurate output value is obtained. You will be able to do it.

Further, the current value converted by the current conversion unit is A / D converted, and the output from the force plate 2 determined to have been treaded by the tread plate detecting means 32 is different from the output from the other force plate 2. Since the voltage value is changed and output to the foot position calculating means 42 as described above, it becomes possible to determine which force plate 2 is pressed by the voltage value.

The present invention is not limited to the above-described embodiment, and can be realized in various embodiments.

For example, in the above embodiment, the case of analyzing the running state of a subject performing athletics has been described as an example, but it can be used for motion analysis of sports in all fields such as gymnastics and ball games. It can also be applied to motor analysis of patients undergoing rehabilitation.

Further, in the above embodiment, the force plates 2 are laid in a straight line, but the force plates 2 may be arranged in a plane so that motion analysis can be performed. In this case, when the boundary portion of each force plate 2 is pressed, the load may be output from the force plate 2 and a plurality of force plates 2 adjacent thereto to calculate the COP.

Further, in the above embodiment, the number of the pressed force plate 2 can be determined by changing the voltage for each force plate 2, but identification information is given to each force plate 2 so that the force plate 2 can be determined. When the pressure is pressed, the identification information may be output together.

Further, in the above embodiment, the COP is calculated by the control unit 4, but the COP may be calculated by the centralized relay board 3 or the personal computer 5.

Further, in the above embodiment, the load, the moment, the position of the foot, etc. are calculated, but the position of the center of gravity may be calculated.

1 Motion analysis system 2 Force plate, 21 load cell, 22 A / D conversion unit, 23 component force calculation unit, 24 D / A conversion unit, 25 current conversion unit 3 Centralized relay board, 31 A / D conversion unit, 32 treading plate Detection means, 33 Output means 4 Control unit, 41 A / D conversion unit, 42 Foot position calculation means 5 PC, 51 Display means

Claims (3)

In a motion analysis system in which a plurality of force plates having load cells are laid along the traveling direction of the subject and the load and position of the subject traveling forward on the laid multiple force plates are detected.
Among the plurality of force plates, a tread plate detecting means for detecting the force plate pressed by the subject and a tread plate detecting means.
An output means that outputs the output value of the load cell only from the force plate determined to be pressed by the tread plate detecting means and the adjacent force plate in front of the force plate in the traveling direction .
A foot position calculation means that calculates the position of the subject's foot from the value output by the output means, and
A display means for displaying the foot position calculated by the foot position calculation means and the output value of the load cell, and
A motion analysis system that is equipped with. When it is determined by the treading plate calculating means that the boundary between the two force plates is treaded at the same time, the output values of all the load cells of the two force plates that are treaded at the same time are output and the treading plate is detected. The motion analysis system according to claim 1, wherein it is determined that the force plate in front of the subject is trampled in the direction of travel of the subject by means. What force by the output from the previous SL treading plate detector force plate that is determined to have been stamping pressure in, and outputs by changing the output differently voltage value from the other force plate by the magnitude of the voltage value The motion analysis system according to claim 1 or 2 , wherein it is possible to determine whether or not the plate has been treaded .

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