JPS60261433A - Stepping inspection apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] "Purpose of invention" (Industrial application field) Concerning testing of human balance function in hospitals, etc.

(Prior art) - A foot test is a method of testing a person's balance function, and it is carried out using a secondary procedure as shown in Figure 8. Shoin).

(1) A radius of 0.5 m divided by 30 degrees on the floor.

Three concentric circles 13 of 1 m and 1.5 m are drawn, and the subject 14 is made to stand with both feet together at the center of these concentric circles.

(2) Next, the subject's eyes were lightly shielded with a piece of cloth to deprive him of his vision.
Extend both upper limbs forward, raise the thighs high in a standing position, but have the patient lightly step on the feet without applying too much force. Step at a normal pace (110 steps in and out per minute) and take 50 or 100 steps. For the footstep test, choose a quiet room with no one-sided light, and do not talk to the test subject during the test, using light or sound stimulation to prevent the test subject from judging changes in his or her body position.

(3) The examiner is referring to the subject who is stepping.

a. Presence or absence of bodily movement, and if so, its direction.

50 Changes in the relative position of the head to the body.

C0 Are the upper limbs on both sides ascending or descending from their original position (forward extension position), or are they biased to the side?

d, Trajectory L of both footprint movements.

(4) When you have completed the commanded number of steps and stopped, stand still at the stopped position and check how many times your body has rotated around its own long axis. The number of times the robot has moved is measured quantitatively by concentric lines drawn on the floor.

When the body unconsciously rotates or moves from its original position due to natural foot stepping, this is called foot deflection, as shown in Figure 8. OR, transition angle AOD, transition. Measure the distance r and objectively describe the nature and degree of foot deviation.

(Problem to be solved by the invention) However, the conventional method has the following problems.

(1) Because all observations are done visually, accurate quantities cannot be determined.

(2) The trajectory of the movement of both footprints is not accurate because it is visually observed by the examiner, and it is difficult to record the progress over a period of 9 hours.

(3) Only the rotation angle, transition angle, and transition distance at the time when the foot pedal is completed are measured, and the time course thereof cannot be quantitatively grasped.

(4) Regarding the measurement of the rotation angle, transition angle, and transition distance at the end of stepping, sufficient accuracy cannot be expected because the measurements are based on concentric circles with 0 and 5 m intervals separated by 30 degrees.

(5) Since there are many subjective elements in general, only an examiner with sufficient knowledge and experience can conduct an accurate examination.

On the other hand, conventional floor reaction force meters or so-called center of gravity oscillation meters have been manufactured. A floor skin dynamometer is a device in which a flat plate called a measuring plate with sufficient rigidity is supported by three or more weight sensors, and outputs an electrical signal proportional to the load applied to the weight sensors. A center of gravity sway meter is a device that calculates the two-dimensional center position of the load distribution on the measurement plate by calculating the output of the floor skin dynamometer, and usually has two outputs in the X direction and Y direction. Outputs an electrical signal proportional to each coordinate value. The point indicated by the output is called the center of gravity.

Some of these devices are commercially available as foot test analysis center of gravity meters. However, this device simply outputs the two-dimensional center position of the load on the measuring plate when stepping on the measuring plate, that is, the center of foot pressure distribution (hereinafter referred to similarly); It is not possible to directly measure the rotation angle, transition angle, transition distance, and transition trajectory, which are measurement items in inspection.

(Purpose of the invention) The objects of the present invention are as follows.

(1) Measurement and recording of rotation angle, transition distance, transition distance, and transition locus, which are measurement items in foot testing, are performed automatically and with high accuracy.

(2) Measure and record the time course of one rotation angle, transition angle, and transition distance, which could not be measured conventionally.

(3) By also recording the center of foot pressure distribution during stepping.

It makes it possible to contrast the sway of the body and the bias of the foot.

(4) After completing the measurement, record the results in a format that makes it easy to analyze them.

"Structure of the Invention" (Means for Solving the Problems) As illustrated in FIG. 1, an apparatus is used which can be broadly divided into a floor reaction force meter section 1, an analysis section 2, and an external device 3.

The floor reaction force meter section 1 includes weight sensors CH1 to four corners of the measurement plate 4.
CH4 is arranged to amplify the output signal of the two weight sensors to a sufficient magnitude.

The analysis section converts the four-point weight signals from the floor reaction force meter section from analog to digital, analyzes them using a microcomputer, and sends the analysis results to an external device (printer).

output to a plotter, personal computer, etc.).

Algorithms for analyzing footstep data can be broadly divided into three types:

(1) Calculate the center of foot pressure distribution from the data at four points.

(2) From changes in the center of foot pressure distribution or changes in total weight,
The state of foot stepping at that moment is judged, and the representative position on the measuring board of the foot that is in contact with the ground when the person temporarily stands on one foot during two-foot stepping is determined.

(3) - From the representative position of the foot for each step, determine the center and direction of the body at that time, and determine the rotation angle, transition angle, and transition distance of the body.

Output the results of the analysis process to an external device.

(Function) The floor reaction force meter section amplifies and outputs the load applied to each weight sensor as an electric signal to a sufficient magnitude when a person on the upper or lower side of the measurement plate steps on the plate.

The analysis section converts each weight signal from the floor reaction force meter section into a digital value using an analog-to-digital converter, and analyzes this. The analysis algorithm will be explained below using FIGS. 2 to 4.

(1) Calculation of the center of foot pressure distribution The center of foot pressure distribution is calculated from the weight data applied to each sensor converted into digital values. As shown in Figure 2, the center of foot pressure distribution P (
The calculation formula for calculating x, y) is given by the following formula.

1: Distance between the sensors in the x-axis and y-axis directions
/input data from the D converter) woi: Calculation of the load applied to the sensor 1 when there is no load on the measuring table is performed for 50 samples per second.

(2) Determining the state of stepping and calculating the representative position of the foot Next, the state of stepping is determined (are you standing on one foot or are you switching steps?) and the switching of the two feet begins. Once you have determined that this is the case, find the representative position of the foot that was in contact with the ground when you were standing on your heel just before that point.

The following methods can be considered for determining the state of foot stepping.

Judgment is made based on the speed of movement of the a0 foot pressure distribution center.

b. Judgment is made based on the change in the total load applied to the measurement plate.

c. Considering a coordinate system fixed to the subject, judgment is made based on the center of foot pressure distribution within this coordinate system.

Here, method a will be explained.

In other words, when the subject steps on the measurement board.

The X coordinate of the constant pressure distribution center, the X coordinate, and the moving speed/degree.

They change as shown in FIGS. 3(a), (b), and (c), respectively. However, FIG. 3 shows a situation where the subject steps while facing the positive direction of the y-axis.

That is, the positive direction of the y-axis is the front of the subject, the negative direction is the rear, the positive direction of the X-axis is the right, and the negative direction is the left.

Generally, the X coordinate of the center of the foot pressure distribution and the graph of the X coordinate are:
It depends on where the subject steps and in which direction. However, the graph of the movement speed of the center of one foot pressure distribution does not change regardless of the position or orientation on the measurement plate. Moreover, the movement speed.

It takes a large value when switching legs, and becomes almost zero during the period of standing on two legs. Therefore, this is used to judge the state of foot stepping. But as it is.

Since there are ups and downs in short periods, filter processing is performed as shown in FIG. 3(d) to create a smooth graph.

After filtering the moving speed, the section where the value is greater than the threshold value is determined to be during switching of feet, and the section where the value is smaller than the threshold value is determined to be the section of standing on one leg. As shown in FIGS. 3(a) and 3(b), the center of the foot pressure distribution corresponding to the minimum value in the one-legged standing section is regarded as the representative position S of the foot in contact with the ground.

(3) Calculating the center position and direction of the body During normal foot stepping, there are few changes in the center position and direction of the body with each step, so as shown in Figure 4, the representative positions of successive feet are The midpoint of the line segment connecting (N) and S(N+1) can be regarded as the center position of the body M(N, N+1), and the direction perpendicular to this line segment can be regarded as the direction of the body D(N, N+1).

However, this alone does not determine the direction. Therefore, in normal stepping, the body direction does not change by more than ±90 degrees during a negative step, so by sequentially tracking from do at the start of one step, the body direction d (N, N + 1) can be determined. I have decided.

From the center position and orientation of the body at that time and the center position and orientation of the body at the start of stepping, the rotation angle AOR(N) of the body at that time is determined as shown in FIG.

N+1), the transition angle AOD (N, N+1), and the transition distance R(N, N+1).

Measure footsteps for a predetermined number of steps, and analyze the obtained data according to the steps (1) to (3) above.

The results are output to an external device.

(Embodiment) FIG. 1 shows a block diagram of an embodiment of the footstep inspection device of the present invention.

This device is roughly divided into a floor reaction force meter section 1, an analysis section 2, and an external device 3.

Although the floor reaction force meter section 1 may have other shapes in principle, it has a shape in which weight sensors CH1 to CH4 are arranged at the four corners of a square measuring plate 4 with a side of 1.5 m. The output signal of each weight sensor is amplified to a sufficient magnitude by an amplifier circuit 5.

The analysis section 2 sequentially takes in the four-point weight signals from the floor reaction force meter section 1 using a multiplexer 6, passes through a sample hold circuit 7, and converts them from analog to digital at a rate of 50 samples per second using an A/D converter 8.

It is analyzed by the microcomputer 9 and the analysis result is sent to the printer 10. Plotter 11. personal computer 12
etc., to an external device 3.

The operating procedure is shown in FIG. 5, the processing procedure for measurement, that is, determining the representative position of the foot, is shown in FIG. 6, and the data analysis method is as explained in the section on the above-mentioned operation. All processing is performed digitally by the microcomputer 9, but some of the processing may also be performed using analog circuits.

An example of outputting and illustrating the results of the analysis process to the plotter 11 is shown in FIG.

"Effect of the invention" This invention provides the following effects.

(1) By automating the measurement and recording of the footstep test, even an inexperienced examiner can easily perform the footstep test.

(2) Measurement results can be kept as objective and easy-to-understand records.

(3) It is possible to accurately measure the trajectory of the footstep, which previously could only be measured visually. In particular, the progress of each step along the trajectory becomes clear.

(4) It is now possible to understand numerically the progress of each step in rotation angle and transition distance, which was previously difficult to understand numerically.

(5) It becomes possible to analyze the movement of the center position of the foot pressure distribution in comparison with the foot deviation.

(6) Since measurement results and analysis results can be transferred to other computers, more advanced analysis or data storage is possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the footstep inspection device of the present invention, FIG. 2 is a diagram illustrating a method for calculating the center of foot pressure distribution in the present invention, and FIG. FIG. 4 is a diagram illustrating a method for determining the determination and representative position of the foot, and FIG. FIG. 5 is a flowchart showing the operation of the apparatus according to the embodiment of the present invention. FIG. 6 is a flowchart showing the procedure for measuring the representative position of the foot in the same example device; FIGS. 7(a) and (b) are diagrams showing an example of the analysis results output to the plotter; FIGS. 8(a) and 8(b) are diagrams showing a conventional measurement method. 1... Floor reaction force meter section, 2... Analysis section, 3... External device. 4...Measuring plate, 9...Microcomputer. 11... Plotter, CH1-CH4... Weight sensor. P: Center of foot pressure distribution, S: Representative position of the foot. L... Line segment, M... Center position of the body, D... Direction of the body. d...body orientation, AOR...body rotation angle. AOD...Body transition angle, R...Body transition distance Patent applicant Sanyo Electric Manufacturing Co., Ltd. 1R Figure 2 Wt Wz P: Foot pressure distribution center χ: Foot pressure distribution center χ coordinate 1 : 1 coordinate of the center of foot pressure distribution 0: Origin WO E: Load applied to weight sensor A when no load wt] Load applied to weight sensor L when the subject is on the measurement table: Distance between weight sensors 3rd Figure 4m (N): Representative position of the N red eye foot (N+1): Representative position of the N red eye foot (AI, N+1): Center position of the body during N-N+1 steps (MO: At the start of the step) body center position) CN, N+1
): Body direction during N-N+1 steps] (N, N+13
: Transition angle of the body between N-N steps (N, N+-IC
Body transition distance during N-NH step Figure 8 (a) Figure 8 (b)

Claims (1)

[Claims] A floor reaction force meter section that supports a measurement plate with three or more weight sensors and outputs an electrical signal proportional to the load applied to each weight sensor, and an output from this floor reaction force meter section. It consists of an analysis section that performs arithmetic processing and an external device that records or separately analyzes the analysis results, and measures the load of the person stepping on the measurement plate.
The floor reaction force meter section outputs the signal, and the analysis section outputs the signal based on this output. Calculate the center of foot pressure distribution, 9 Next, from this center of foot pressure distribution, find the representative position of the foot stepping on the measurement board. 2 Next, from this representative position of the foot, find the center position and direction of the body at that time. Based on this and the orientation of the body up to the moment before the first step, which is tracked sequentially from the start of stepping, the orientation of the body at that time is determined, and from this, the rotation angle of the body due to stepping, J) the transition angle of the body, and the A footstep inspection device characterized in that the transition distance is calculated and each value obtained by one or more analysis sections is recorded or analyzed by the external device.