JPH04354938A - Center of gravity movement detector - Google Patents

Abstract

PURPOSE:To determine a correct center of gravity moving trace of a person to be trained by reducing effect of vertical vibration associated with the movement of the center of gravity in a movement function training device which is adapted to move a floor surface askew. CONSTITUTION:A floor reaction meter having a plurality of load cells is supported rotatably on a fixed frame through an internal frame member and a external frame member. Free ends of a plurality of stretching means are retained on the rear of the floor reaction meter and the stretching means are stretched or reduced selectively to obtained an inclined surface optionally. Outputs Pi of load cells are sent to an arithmetic means, and first, the sum SIGMAPi of the outputs is determined (step 101). At this stage, noises are overlapped by vibration, and hence, the SIGMAPi is not constant. Then, 1/4SIGMAPi is calculated (step 102: the number of load cells used for computation is set at 4). A subtraction is performed from the outputs of the load cells (step 103). Thus, noises caused by vibration are removed. Thereafter, the center of gravity of a person to be trained is calculated based on a correction signal obtained (step 104).

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a device for detecting the movement of the center of gravity, and more specifically, the present invention relates to a device for detecting the movement of the center of gravity of a person standing on the floor by artificially applying a tilting motion or a horizontal movement motion to the floor surface, and detecting the movement trajectory of the center of gravity of a person standing on the floor. This relates to a device for

0002

[Prior Art] As society ages, the number of people with paralyzed or impaired physical functions due to diseases such as stroke is increasing, or reflecting a high stress society, people in their prime age have impaired motor functions due to stroke, etc. The number of people with disabilities in physical functions, particularly motor and balance functions, is increasing due to a variety of factors, including an increase in the number of people with motor function impairments due to traffic accidents.

[0003] Among these disorders of motor function and balance function, mild disorders can be recovered by training, and various devices for functional recovery training are provided. Conventional devices of this type tilt the floor surface alternately in the left-right direction or in the front-back direction, or move the floor surface continuously without track, and although they are inexpensive, they are difficult to use in daily life. The drawback was that it was not possible to perform complex movements in accordance with the current situation with a single device.

On the other hand, it is being carried out at the laboratory level to quantitatively understand the degree of functional recovery of trainees and to utilize this information in subsequent training. In other words, the data of the trainee is compared with that of a healthy person, and subsequent training is planned in a planned manner. In this case, a method is mainly used to obtain the trajectory of the center of gravity through the feet of the trainee in a standing position, and a floor reaction force meter is used as the detection means. Conventional floor reaction force meters work well when installed horizontally and stably, but have the disadvantage that load detection becomes inaccurate on inclined or moving surfaces.

[0005] Therefore, the inventors of the present application developed a dynamic balance function training device as a device that can freely combine complex movements such as tilting and moving, and can also detect loads on inclined surfaces and moving surfaces. Equipment (Patent Application Hei 1-216840
No.) was proposed first. This device has an outer frame rotatably latched to a fixed frame, and an inner frame rotatably latched to the outer frame and having a rotation axis coplanar and orthogonal to the rotation axis of the outer frame,
A floor reaction force meter equipped with a plurality of load cells is arranged within this inner frame. This device has a plurality of telescoping means, one end of which is fixed to a fixed frame and the other end of which is locked to an inner frame (i.e., a floor reaction force meter), and by selectively expanding and contracting the telescoping means. , it is possible to create any slope.

[0006]

[Problems to be Solved by the Invention] However, in the conventional functional training device as described above, the center of gravity of the trainee is determined by calculating the outputs from the plurality of load detection means (load cells) of the floor reaction force meter. However, there were the following problems when analyzing the output signal of the load cell.

That is, the floor surface of the functional training device connected to the free end of the extensible means is expressed as a damped vibration system in which a spring with a spring constant k and a dashpot with a viscous resistance coefficient η are connected in parallel, as shown in FIG. movement of the floor surface (tilting movement, etc.)
If this is done, vertical vibrations will occur on the floor surface. Therefore, as shown in FIG. 6, the output of each load cell R placed on the floor contains a component due to vibration in addition to the normal signal related to the movement of the center of gravity. In other words, when the center of gravity of a trainee with mass M moves, if the load on one load cell decreases, the load on another load cell increases by that amount, and the sum of the loads detected by all load cells remains constant. It should be. However, in the damped vibration system as described above, the acceleration component of the vibration motion is applied to the load cell until the vibration is damped, and the sum of the outputs of each load cell is not constant with respect to the time axis. However, even if one attempts to directly calculate the center of gravity from the output (or amplified signal) of each load cell as in the past, it is not possible to obtain an accurate center of gravity trajectory.

[0008] The present invention has been made in view of the above-mentioned points, and in carrying out functional recovery training for disabled persons by moving the floor surface connected to the free end of the extensible means.
It is an object of the present invention to provide a center of gravity movement detection device that can accurately determine the locus of the center of gravity of a trainee.

[0009]

[Means for Solving the Problems] The center of gravity movement detecting device of the present invention comprises a plane connected to the free end of an extensible means, and a plurality of load detecting means arranged on the plane. In order to achieve the above object, an attenuation signal obtained by attenuating a signal corresponding to the sum of the output signals of the load detection means at a predetermined rate is subtracted from the output signal of each of the load detection means, and the subtracted correction is performed. It is equipped with a calculation means for calculating the center of gravity based on the signal.

0010

[Operation] Signal processing according to the present invention will be explained with reference to FIG. 1 showing a signal processing flowchart in a functional training device (center of gravity movement detecting device) of an embodiment described later. First, find the sum ΣPi of the outputs Pi from each load cell placed on the floor connected to the free end of the expandable means (
Step 101). As shown in the figure, this ΣPi is obtained by superimposing the waveform of the damped vibration accompanying the tilting motion of the floor surface on the signal of the normal movement of the center of gravity. Next, ΣPi
x 1/4 (step 102; the value 1/4 is not limited, but is determined according to the number of load cells used in the calculation. Here, four load cells are calculated for one floor reaction force meter. ), 1/4ΣPi is subtracted from the output Pi of each load cell (step 103). As a result, unnecessary vibration waveforms (the waveform of load cell 1 is shown in the figure) are removed from the output signals of each load cell, and the asymmetry of the output signals from each load cell is improved. In other words, if the center of gravity, which was located near load cell 8, moves to near load cell 1, the waveforms of the output signals of load cells 1 and 8 will become almost symmetrical with respect to the time axis, and from the output of each load cell, 1/4ΣPi The correction signal obtained by subtracting Wi (wi for the sake of explanation) is close to the theoretical value.

Therefore, by calculating the center of gravity based on this correction signal Wi (step 104), it is possible to obtain an accurate locus of the center of gravity that is not affected by vibrations in the vertical direction. To calculate the center of gravity, set the coordinates of the center of gravity to (x, y)
, the coordinates of the placement position of each load cell are (xi, yi)
It is calculated as follows. x={Σ(Wi xi )}/ΣWi y={Σ(Wi yi )}/ΣWi...Formula 1 By performing this center of gravity calculation over time, the locus of the center of gravity of the trainee can be found. In the example of FIG. 1, the center of gravity of the trainee's left foot hardly moves in the X-axis direction, but moves largely in the Y-axis direction.

0012

[Embodiment] FIG. 4 shows a functional training device (
FIG. 2 is a schematic perspective view showing the configuration of a gravity center movement detection device. In the figure, an inner frame member 201 is rotatably locked to an outer frame 202 around a rotating shaft 204.
02 is a rotation axis 2 that is on the same plane as the rotation axis 204 of the inner frame 201 and orthogonal to the rotation axis 204 of the inner frame 201 (intersection point P).
It is locked to a fixed frame 203 so as to be rotatable about 05.

A floor reaction force meter 100 having an upper plate, a supporting plate (not shown), and eight load cells 1 to 8 sandwiched between the two plates is arranged in the inner frame 201. Each of the load cells 1 to 8 is arranged along two opposing sides of the floor reaction force meter 100.
Four pieces are arranged at equal pitches. Further, each of the load cells 1 to 8 is connected to a calculation means 9 that includes a display means and a printing means 10.

The expansion and contraction means 206 and 207 are the floor reaction force meter 10
They are arranged in areas A and B divided into two by the inner frame rotation axis 204 of 0, one end is fixed to the fixed frame 203, and the other end is locked to the inner frame 201 (i.e., the floor reaction force meter). The height in the vertical direction is variable by a motor (not shown). The expansion and contraction means 206 and 207 are also connected to the calculation means 9, and the expansion and contraction operations are controlled by the calculation means 9.

Next, the operation of the apparatus shown in FIG. 4 will be explained. First, in the initial stage, the inner frame 201 and the outer frame 202 are held on the same horizontal plane. Next, for example, the expansion and contraction means 2
06 and 207 are alternately moved up and down, the inner frame 201 rotates about the rotating shaft 204, and the floor surface is inclined in the left-right direction (in the direction of areas A and B) in the drawing. Furthermore, if the expansion/contraction means 206 and 207 are moved up and down simultaneously, the areas A and B will move up and down with respect to the areas C and D, and the floor surface will be inclined in the longitudinal direction of the paper. Furthermore, it is also possible to tilt in the diagonal lines V and W directions by holding either one of the expansion and contraction means 206 and 207 at a middle position and making the other expand and contract. By selectively expanding and contracting the expansion and contraction means 206 and 207 in this manner, it becomes possible to arbitrarily incline the floor surface. Although not shown in FIG. 1, the floor surface can also be moved horizontally by moving the fixed frame 203 together with a prime mover.

Now, by moving the floor surface as described above, the center of gravity of the trainee moves, but please refer to FIGS. 2 and 3 for the processing of the output signals from each load cell 1 to 8. I will explain. In Figure 2, each load cell (
For simplicity, the output signals from four load cells 1 to 4 are shown in the figure) are sent to arithmetic means and amplifiers 11 and 11 respectively.
~ 14, the analog signal is further converted into a digital signal by the A/D converter 15, and then sent to the CPU 16 of the calculation means.
sent to.

The CPU 16 performs calculations according to the flowchart explained in FIG. First, the sum ΣPi of the digitally converted output signals is determined (step 1
01), and 1/4ΣPi is further calculated (step 102). Next, from the output signal of each load cell, 1/
4ΣPi are each subtracted (step 103). As shown in FIG. 3, the asymmetry of the output signal Pi of each load cell is improved in the correction signal (=Wi) obtained by subtracting this 1/4ΣPi, and ΣWi becomes approximately constant. That is, from the output signal of each load cell, 1/
By subtracting 4ΣPi, the vertical force applied to the floor surface when the trainee moves the center of gravity (=M (mass) x a
(acceleration)) is removed, and a signal resulting from normal center of gravity movement is extracted. Next, this correction signal W
Based on i, the center of gravity is calculated using Equation 1 described above (step 104). This calculation is performed over time, and the locus of the movement of the center of gravity is displayed on the monitor, and various analyzes are performed from the correction signal Wi as necessary.

In this embodiment, except for the signal processing system, a device similar to the functional training device proposed by the applicant in Japanese Patent Application No. 1-216840 is used.
The device itself for realizing horizontal movement is not limited to the device of the above embodiment. For example, even in a device that repeats tilting motion only in the front-rear direction (or left-right direction), by performing the signal processing described above, it is possible to reduce the effects of vertical vibrations that occur with the motion, and to achieve accurate Analysis becomes possible.

Further, in the above explanation, a functional training device used for functional recovery of humans was described, but the center of gravity movement detection device of the present invention is suitable for testing the motor function of animals, machines (robots), etc. Needless to say, it can also be used for

[0020]

[Effects of the Invention] As described above, in the center of gravity movement detection device of the present invention, the output signal of each load detection means is corrected by a specific calculation, and the center of gravity is calculated based on the corrected output signal. Therefore, the influence of vibration in the vertical direction accompanying the movement of the center of gravity is reduced, and it becomes possible to obtain an accurate trajectory of the movement of the center of gravity. If the center of gravity movement detection device of the present invention is applied to a functional training device for people with motor dysfunction, it is possible to accurately analyze the motor function of the trainee, which is very useful in conducting planned training. .

[Brief explanation of drawings]

FIG. 1 is a flowchart showing a signal processing process of a gravity center movement detecting device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of a signal processing system of the gravity center movement detecting device according to the embodiment of the present invention.

FIG. 3 is a conceptual diagram showing signal waveforms in the gravity center movement detection device according to the embodiment of the present invention.

FIG. 4 is a schematic perspective view showing the configuration of a center of gravity movement detecting device according to an embodiment of the present invention.

FIG. 5 is a conceptual diagram for explaining vibration in the vertical direction due to movement of the center of gravity.

FIG. 6 is a conceptual diagram showing signal waveforms in a conventional device.

[Explanation of symbols]

1, 2, 3, 4, 5, 6, 7, 8 Load cell 9
Calculating means 10 Printing means 11, 12, 13, 14 Amplifier 15 A/D converter 16 CPU 17 Display section 100 Floor reaction force meter 201 Inner frame 202 Outer frame 203 Fixed frame 204 Inner frame rotation axis 205 Outer frame rotation axis 206, 207 Expanding means

Claims (1)

[Claims] 1. A flat surface connected to a free end of the telescoping means, and a plurality of load detection means disposed on the flat surface,
In the center of gravity movement detection device for detecting movement of the center of gravity of an object on a plane, an attenuated signal obtained by attenuating a signal corresponding to the sum of the output signals of the load detection means at a predetermined rate is obtained from each output signal of the load detection means. A center of gravity movement detecting device comprising: arithmetic means for calculating a center of gravity based on the subtracted correction signal.