JP2004329280A - Floor reaction force estimation device using sole pressure, and estimation system of leg joint moment and leg muscle tension using the device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a floor reaction force estimation device using a sole pressure capable of executing with inexpensive equipment without putting burdens on a patient or a testee and without the restriction of a location, and an estimation system of a leg joint moment and leg muscle tension using the device. <P>SOLUTION: As for the floor reaction force estimation device and the system using the device, the device is for estimating floor reaction force from a pressure applied to the sole while the testee walks and is composed of footwear that the testee puts on to walk, a sensor which reacts to the floor reaction, such as a pressure sensor arranged on the surface of the footwear and an analyzer for analyzing the measured value of the sensor. The sensor is arranged on at least four or more places on the surface of the footwear. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

その係数を重回帰分析法を用いて求める。
具体的に、重回帰係数（Ａ_ｉ）及び回帰係数（Ｂ）を求めるための方法を以下に記載する。
【００１４】
▲１▼被験者に上記した履物（１）を履かせて、右足のみを床反力計に乗せ、左足は床の上にあるようにする。このとき、身体の中心線が床反力計と床の境界上になるようにする。
▲２▼被験者には特別な指示は与えず、足位置は固定したままで体重心を上下左右に変化してもらい、床反力を測定する。
▲３▼重回帰分析にて各センサ（２）が測定している等価面積に対応する係数（Ａ_ｉ）を求める。その際、床反力の鉛直方向の力［Ｎ］を従属変数（Ｙ）、６個のセンサ（２）からの足底圧値［ｋｇｆ／ｃｍ^２］を独立変数（Ｘ_ｉ，・・・，Ｘ_ｎ）として用いる。
【００１５】
図５は立脚期に足部にかかる力の矢状面内での様子を示している。尚、図５中の記号は以下の通りである。
Ａ_１Ｘ_１，Ａ_ｉＸ_ｉ：各センサにかかる床反力の鉛直方向成分
Ｎ：床反力の前後成分
ｈ：足首関節軸と各センサまでの垂直距離
ｌ_１，ｌ_ｉ：足首関節軸と各センサまでの水平距離
ｌ_ｇ：足首関節軸と足部の重心との水平距離
ｍ：足部の重量
【００１６】
上記▲３▼で得られたＡ_ｉを用いれば、床からの反力は図４のように各センサの位置に加えられる鉛直方向（Ａ_ｉＸ_ｉ）の合力であるとみなせる。各センサの足首関節に対する位置は既知であるので、足首関節周りのモーメント（Ｍ）は慣性力を無視すれば、次式（ｂ）のように表記できる。

さらに、第２項のＮｈ及び第３項のｍｇｌ_ｇは、第１項に比べて十分小さいと考えられるので無視すれば、次式（ｃ）となる。

なお、足首関節位置から各センサまでの相対位置（ｌ_１，・・・，ｌ_６）はセンサの取り付け位置から定数として決まる。
【００１７】
図５は、上記した重回帰分析にて導出した回帰係数と偏回帰係数を示す一覧表である。
この表はセンサ数６個、全６３通りの組み合わせを示しており、左端より「踵部」、「第１ＭＰ関節部」、「第４ＭＰ関節部」、「母趾部」、「第３趾部」の偏回帰係数、「回帰係数」、精度の高さを示す「Ｒ」値、「センサの数」の順で表記している。尚、この一覧は精度のよい「Ｒ」値の高い降順で表記している。
【００１８】
図５に示すように、センサの数が多いほど精度が高いことが認められる。上位２２通りまでには踵部が必ず含まれた。通常、健常な歩行を行うためには、踵接地が重要であり、精度のよい計測結果を得る為には踵部のセンサが必須であると考えられる。また、センサ数５個の組み合わせの中で踵部を除いた組み合わせ（Ｎｏ．２３）が最下位であったことからも同様に考えられる。
また、上記１０通り中にセンサ数４個の組み合わせが５通り含まれていることから、センサ数は、組み合わせ次第では適当な４箇所のみでも高い精度で床反力を測定可能であると考えられる。
また、上位５通りの組み合わせ結果から、足部を「踵部」、「足弓部」、「中足骨部」、「趾部」の４分割にできるものと考えられる。従って、センサは４分割された各部分に最低１つずつ配置すれば、高い精度をもって床反力を測定することが可能であることが推察される。
従って、本発明においては、圧力センサは履物に少なくとも４箇所以上、具体的には「踵部」、「足弓部」、「中足骨部」、「趾部」の４箇所に最低１つずつ設けることとする。尚、より高い測定精度を求める場合には５箇所以上に設けるとよいが、７箇所以上設けても精度の向上は余り期待できないため、４〜６箇所の範囲内で設定することが好ましい。
【００１９】
本発明に係るシステムにおいては、上記した如く、圧力センサにより被験者の歩行中の床反力及び足関節モーメントを推定した後、被験者の歩行中の膝関節及び／又は股関節の位置を求めるが、この際には以下の２種類の手段のいずれかが用いられる。
先ず、第一の手段について説明する。
第一の手段は、履物（１）に取り付けられて被験者の歩行中の足首の角度を測定する角度測定センサ（４）と、解析装置（２０）に備えられた関節位置推定手段とからなる。関節位置推定手段は、角度測定センサ（４）により測定された被験者の足首角度に基づいて、被験者の歩行中の膝関節位置及び／又は股関節位置を推定する。或いは、膝関節の角度を足首とセンサ（４）で測定してもよい。
角度測定センサ（４）としては、特に限定はされないが、例えばゴニオメータを使用することができる。
関節位置推定手段による膝関節位置及び／又は股関節位置の推定は、予め被験者の体型（足の長さなど）を測定しておき、その体型に合った骨格モデルに対して、測定された足首角度を適用することで行うことができる。
【００２０】
第二の手段は、被験者の歩行時における足の動きをＣＣＤカメラ（５）で撮影し、信号処理をして被験者の歩行中の膝関節位置及び／又は股関節位置を測定する関節位置測定手段からなる。
この測定手段による測定は、被験者の膝や股関節などの特定位置にマーカーを取り付け、カメラで被験者の歩行中における足の動きを球状のマーカーの軌跡を捉えることで行う。
尚、この測定においては、カメラが被験者の膝や股関節の動きを正確に捉えるために、例えば、被験者の側方への延出部を有する車輪付き台車などにＣＣＤカメラを取り付け、被験者が台車を押しながら歩くことで、カメラが被験者の足の動きを側方から被験者と同じ速度で動きながら撮影できるようにすることが好ましい。また、従来から用いられている複数のカメラの情報から３次元動作を計測する方法では、スペースが大きくなりがちであるので、１台のカメラとマーカーの画像としての断面積あるいは直径等の画像の大きさに関わる情報と画像でのマーカーの位置に関する情報からマーカーの方向とマーカーまでの距離を推定し、その情報からマーカーの３次元位置を推定する方法を用いれば、小さいスペースでの計測が可能となる。
【００２１】
上記した２通りのいずれかの手段を用いて求められた被験者の歩行中の膝関節位置及び／又は股関節位置のデータは、解析装置（２０）に入力される。
解析装置（２０）には、各関節（足首関節、膝関節、股関節）の位置データと、前述した床反力の推定値を用いて、被験者の歩行中の各関節のモーメントを推定する関節モーメント推定手段と、得られた関節モーメントの推定値から被験者の筋張力を推定する筋張力推定手段が備えられており、これら各手段によって膝関節及び股関節のモーメント及び筋張力が推定される。尚、足関節位置については、上述した如く圧力センサと足首の相対位置が既知であるため、膝関節位置や股関節位置のように別途推定する必要はない。
【００２２】
以下、解析装置（２０）による関節モーメント及び筋張力の推定方法について具体的に説明する。
推定に際しては、図６に示すような筋骨格モデルが用いられる。
筋骨格モデルは、下肢の関節を駆動する際に支配的な９つの筋肉（▲１▼大腿直筋、▲２▼大殿筋、▲３▼ハムストリング、▲４▼広筋、▲５▼大腿二頭筋短頭、▲６▼腓腹筋、▲７▼ヒラメ筋、▲８▼前頚骨筋、▲９▼腸腰筋）からなる。
この方法は、ある時刻ｔに、この９つの各筋肉に加わる張力を、床反力のデータと、下肢の各関節の位置データ、および人体のパラメータから推定する方法である。
【００２３】
以下に、その推定方法の詳細について、順を追って説明する。
（１）床反力のデータと関節の位置データおよび人体のパラメータ１から、各関節に発生するモーメントを次式１（数１）により計算する。
【数１】

ここで、添字１は足首関節、２は膝関節、３は股関節を示している。またＩ_１，Ｉ_２，Ｉ_３は各々足首関節、膝関節、股関節の慣性モーメント、ｍ_１，ｍ_２，ｍ_３は各々足部（足首から先の部分）、下腿部、大腿部の質量、ｘ_ｇ１，ｙ_ｇ１は足部の質量中心、ｘ_ｇ２，ｙ_ｇ２は下腿部の質量中心、ｘ_ｇ３，ｙ_ｇ３は大腿部の質量中心を表しており、これらを総称して人体パラメータ１という。また、Ｎ_ｘ，Ｎ_ｙは各々床反力の鉛直方向成分及び水平方向成分であり、ｘ_０，ｙ_０は任意の位置に固定した原点座標である。
【００２４】
（２）筋肉の張力にモーメントアームを掛け、それらを符号を考慮して足し算したものが、筋肉により発生する各関節のモーメントであるので、次式２（数２）が成り立つ。
【数２】

【００２５】
（３）上記式２に式１で計算した各関節モーメントを代入すれば、３つの方程式が得られる。モーメントアームは既知であるので、この３つの方程式は、９つの筋張力（未知数）の方程式となる。
（４）９つの未知数を３つの方程式のみから一般に求められないので、３つの方程式を満たし且つ次式３（数３）に示す評価関数Ｅを最小にするように９つの未知数（筋張力）を求める。
【数３】

ここで、Ｆ_{ｉ ｍａｘ}は各筋の最大筋張力である。
また、各筋の最大筋張力は、次式で求められる。
Ｆ_{ｉ ｍａｘ}＝ｆ_ｊＰＣＳＡ_ｊ
ここで、ＰＣＳＡ_ｊは筋肉の生理断面積、ｆ_ｊは筋の収縮速度や筋の伸長・収縮量に関する関数である。
【００２６】
以上の方法により、下肢の関節モーメント及び筋張力を求めることができ、このように得られた筋張力のパターンと筋電位のパターンはよく一致することが確かめられている。
【００２７】
本発明に係るシステムにおいては、以上のような方法により、被験者に負担をかけることなく、狭いスペースで、容易且つ安価に、被験者の歩行中の下肢関節モーメント及び筋張力を推定することができる。
【００２８】
【発明の効果】
以上説明したように、本発明に係る床反力推定装置を用いたシステムによれば、従来の方法、例えば被験者に電極を貼り付け筋電位を測定する方法のように、被験者の身体に負担をかけることがなく、また３次元動作解析システムと複数の床反力計を組み合わせる方法のように、場所の制約を受けたり高価な設備を必要とすることがなく、被験者の下肢関節モーメント及び筋張力を容易且つ正確に把握することができる。
従って、歩行リハビリの現場において患者にとってどのようなリハビリが有効かを指導者が判断するための情報や、スポーツ選手のトレーニングにおいてどの部分の筋肉を重点的に鍛えればよいかなどの情報を取得するために極めて有効な方法となる。
【図面の簡単な説明】
【図１】本発明に係る下肢関節モーメント及び下肢筋張力の推定システムの全体構成を概略的に示したブロック図である。
【図２】本発明に係る足底圧計測装置を示す外観図である。
【図３】圧力センサを取り付けた下敷シートの裏面図である。
【図４】立脚期に足部にかかる力の矢状面内での様子を示す図である。
【図５】重回帰分析にて導出した回帰係数と偏回帰係数を示す一覧表である。
【図６】筋骨格モデルの一例を示す図である。
【符号の説明】
１ 履物
２ 圧力センサ
３ 下敷シート
４ 足首角度測定センサ
５ カメラ
１０ 足底圧計測装置
２０ 解析装置
Ｋ 踵部
Ｐ ショパール関節部
ＭＰ 第１ＭＰ関節部
Ｑ 第４ＭＰ関節部
ＭＬ 母趾部
Ｕ 第３趾部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a floor reaction force estimation device and a system for estimating lower limb joint moment and lower limb muscle tension using the same, and more specifically, does not place a burden on a patient or a subject, is not restricted by a place, and has a large scale. The present invention relates to a floor reaction force estimating apparatus using a sole pressure that does not require a system configuration, and a system for estimating a lower limb joint moment and a lower limb muscle tension using the same.
[0002]
[Prior art]
It is extremely important for an elderly person or a patient having a gait function disorder to perform appropriate gait rehabilitation efficiently in order to restore the gait function again.
Currently, in the field of walking rehabilitation, doctors and physiotherapists provide guidance while watching the patient's symptoms and recovery, but if the muscle tension and joint moment can be quantitatively grasped, This is very valuable information for the instructor to determine whether such rehabilitation is effective.
Such information is very useful not only in rehabilitation but also in training in sports.
[0003]
Currently, methods for obtaining such information include (1) a method of attaching electrodes to a patient or a subject and measuring myoelectric potential (for example, see Patent Document 1), and (2) using a plurality of CCD cameras. A method of obtaining a joint moment by applying a dynamic force balancing formula to a large-scale system combining a three-dimensional motion analysis system and a plurality of floor reaction force meters is known.
[0004]
[Patent Document 1]
JP-A-7-67982 [0005]
[Problems to be solved by the invention]
However, the currently used methods as described above have the following disadvantages.
First, the method (1) imposes a heavy burden on the patient and the subject, and requires a long time for preparation. On the other hand, since the method (2) can be measured only by a large-scale, stationary floor reaction force meter, the place and the number of steps are limited, and the method is very expensive.
Therefore, these methods are difficult to use for daily rehabilitation, and are currently used exclusively for research.
[0006]
The present invention has been made in view of such circumstances, and does not place a burden on patients or subjects, and is not restricted by a place, and can be implemented with inexpensive equipment. It is an object of the present invention to provide a force estimating device and a system for estimating lower limb joint moment and lower limb muscle tension using the same.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 is an apparatus for estimating a floor reaction force from a pressure applied to a sole during walking of a subject, the footwear being worn by the subject while walking, and the pressure being placed on the surface of the footwear. A floor reaction force estimation, comprising: a sensor responsive to a floor reaction force such as a sensor; and an analyzer for analyzing a measurement value of the sensor, wherein the sensors are arranged at least at four or more locations on the surface of the footwear. Equipment related.
The invention according to claim 2 is characterized in that the sensor is arranged at least in a portion corresponding to a heel, an arch, a metatarsal, and a toe of a subject's foot. The present invention relates to a floor reaction force estimation device.
[0008]
The invention according to claim 3 is a sole comprising footwear for walking while the subject wears, and a pressure sensor arranged at at least four places on the surface of the footwear and measuring pressure applied to the sole of the subject during walking. A pressure measuring device and an analyzing device for analyzing a measured value by the sole pressure measuring device, and the analyzing device estimates at least a vertical floor reaction force applied to the sole of the subject during walking from the measured value. A system for estimating a lower limb joint moment using a sole pressure, comprising: floor reaction force estimating means; and ankle joint moment estimating means for estimating an ankle moment of the subject during walking from the measured values. The invention according to claim 4 relates to the floor reaction force estimating means of the analyzer, wherein the floor reaction force estimating means of the vertical direction and the horizontal reaction force applied to the sole of the subject during walking are measured based on the measurement value of the sole pressure measurement device. To find the floor reaction force Estimation system of the lower limb joint moments using plantar pressure according to claim 3, wherein.
[0009]
The invention according to claim 5 is provided with an angle measurement sensor attached to the footwear and measuring an ankle angle of the subject while the subject is walking, and the analyzing device is configured to measure the ankle angle during the walking of the subject based on the measurement value of the angle measurement sensor. Position estimating means for estimating the knee position and / or hip position of the subject, and the subject using the estimated value of the knee position and / or hip position estimated by the joint position estimating means and the estimated value of the floor reaction force 5. A lower limb joint moment estimating system using sole pressure according to claim 4, further comprising a joint moment estimating means for estimating a lower limb joint moment during walking.
According to a sixth aspect of the present invention, there is provided a joint position measuring means for measuring a knee joint position and / or a hip joint position of a subject during walking by photographing a foot movement of the subject during walking with a CCD camera and performing signal processing. The analysis device includes a knee joint and / or hip joint of the subject during walking using the data of the knee joint position and / or hip joint position measured by the joint position measuring means and the estimated value of the floor reaction force. 5. A system for estimating a joint moment of a lower limb using a sole pressure according to claim 4, further comprising joint moment estimating means for estimating a moment.
The invention according to claim 7 includes a muscle tension estimating means for estimating a subject's muscle tension by applying an estimated value obtained by the joint moment estimating means to a musculoskeletal model. The present invention relates to a system for estimating lower limb muscle tension.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a sole pressure measuring device according to the present invention and a system for estimating a lower limb joint moment and a lower limb muscle tension using the same will be described.
FIG. 1 is a block diagram schematically illustrating an entire configuration of a lower limb joint moment and lower limb muscle tension estimating system according to the present invention. The system according to the present invention includes a pressure applied to a sole during walking of a subject. Pressure measuring device (10) for measuring the pressure, and personal means for estimating the floor reaction force, the lower limb joint moment and the lower limb muscle tension by analyzing the measured values of the sole pressure measuring device (10) An analysis device (20) including a computer or the like is provided. The floor reaction force estimating device according to the present invention includes the sole pressure measuring device (10) and the analyzing device (20). Each unit provided in the analyzer (20) of the system according to the present invention is composed of various programs executed by the CPU, but these units may be provided in one analyzer. A plurality of analyzers may be provided separately.
[0011]
In the system according to the present invention, first, the pressure applied to the sole of the subject during walking is measured by the sole pressure measuring device (10).
FIG. 2 is an external view showing a sole pressure measuring device (10) according to the present invention, and FIG. 3 is a back view of an underlay sheet to which a pressure sensor is attached.
The pressure sensor (2) includes a heel (K) and a Chopard joint (P) on the back side (see FIG. 3) of an underlay sheet (3) laid on the surface of footwear (1) according to the size of the subject's foot. ), The first MP joint (MP), the fourth MP joint (Q), the toe (ML), and the vicinity (U) of the third toe using a hook-and-loop fastener.
When the subject walks while wearing the footwear (1), the pressure applied to the sole during walking of the subject is detected by the pressure sensors (2) arranged at six places, and outputs from the sensors are connected by wiring. The pressure value is input to a measuring device (not shown) and converted into a pressure value, and the value is input to an analyzer (20) including a personal computer or the like.
[0012]
The analysis device (20) estimates a floor reaction force and an ankle joint moment during walking of the subject from a measured value of the pressure at each point measured by the pressure sensor (2) using a multiple regression analysis program or the like. It has a force estimating means and an ankle moment estimating means.
In the present invention, the floor reaction force (vertical direction) is estimated from the vertical component force applied to the pressure sensor, instead of directly measuring the floor reaction force with a floor reaction force meter as in the related art. As a result, the floor reaction force can be obtained without being restricted by the place or the number of steps.
In addition, in the analysis device (20), not only the vertical component but also the horizontal component of the floor reaction force is obtained from the measured value of the pressure sensor for use in estimating the joint moment described later. For example, the pressure sensor (2) may be embedded in the footwear (1) obliquely or in a mixture of horizontal and vertical directions in the footwear (1), and the oblique, horizontal, and vertical directions measured by the pressure sensor (2) may be measured. There is a method of decomposing a force into a vertical component and a horizontal component (shear), and multiplying them by a predetermined coefficient to obtain a vertical force and a shear force. Note that the sensor used here is not necessarily limited to a pressure sensor, and any sensor that generates an output due to a floor reaction force can be estimated by applying a multiple regression analysis or the like.
[0013]
Hereinafter, a method of estimating the floor reaction force and the ankle joint moment by the floor reaction force estimating means and the ankle joint moment estimating means of the analysis device (20) will be described.
The vertical component force (Y) of the floor reaction force is the sum of the pressure (X _i ) of each sensor section multiplied by a coefficient (A _i ) corresponding to the effective area to which the pressure is applied, as in the following equation (a). Think there is,

The coefficient is determined using a multiple regression analysis method.
Specifically, a method for obtaining the multiple regression coefficient (A _i ) and the regression coefficient (B) will be described below.
[0014]
{Circle around (1)} The subject puts on the above-mentioned footwear (1), puts only the right foot on the floor reaction force meter, and keeps the left foot on the floor. At this time, the center line of the body is set on the boundary between the floor reaction force meter and the floor.
{Circle around (2)} No special instructions are given to the subject, and the weight center of gravity is changed up, down, left and right with the foot position fixed, and the floor reaction force is measured.
{Circle around (3)} A coefficient (A _i ) corresponding to the equivalent area measured by each sensor (2) is determined by multiple regression analysis. At this time, the vertical force [N] of the floor reaction force is a dependent variable (Y), and the sole pressure value [kgf / cm ² ] from the six sensors (2) is an independent variable (X _i ,...). , X _n ).
[0015]
FIG. 5 shows the state of the force applied to the foot in the sagittal plane during the standing phase. The symbols in FIG. 5 are as follows.
A ₁ X ₁ , A _i X _i : vertical component of floor reaction force applied to each sensor N: front and rear component of floor reaction force h: vertical distance l ₁ , l _i between ankle joint axis and each sensor: ankle joint axis And horizontal distance to each sensor l _g : horizontal distance between the ankle joint axis and the center of gravity of the foot m: weight of the foot
With the A _i obtained above ▲ 3 ▼, regarded as a reaction force from the floor is a resultant of the vertical direction applied to the positions of the sensors (A i _{X i)} as shown in FIG. Since the position of each sensor with respect to the ankle joint is known, the moment (M) around the ankle joint can be expressed as the following equation (b) if the inertial force is ignored.

Furthermore, mgl _g of the second term of Nh and third terms, if ignored because considered sufficiently smaller than the first term, the following equation (c).

Note that the relative position (l ₁ ,..., L ₆ ) from the ankle joint position to each sensor is determined as a constant from the sensor mounting position.
[0017]
FIG. 5 is a list showing regression coefficients and partial regression coefficients derived by the above-described multiple regression analysis.
This table shows a combination of 6 sensors and a total of 63 combinations. From the left end, “heel part”, “first MP joint part”, “fourth MP joint part”, “thumb part”, “third toe part” , A partial regression coefficient, a “regression coefficient”, an “R” value indicating high precision, and a “number of sensors”. Note that this list is described in descending order of high-precision “R” values.
[0018]
As shown in FIG. 5, it is recognized that the greater the number of sensors, the higher the accuracy. The heels were always included in the top 22 ways. Normally, heel contact is important for healthy walking, and a heel sensor is considered to be indispensable for obtaining accurate measurement results. In addition, it can be similarly considered that the combination (No. 23) excluding the heel portion among the combinations of five sensors has the lowest rank.
In addition, since five combinations of four sensors are included in the ten patterns, it is considered that the floor reaction force can be measured with high accuracy at only four appropriate locations depending on the combination of the sensors. .
Also, from the results of the top five combinations, it is considered that the foot can be divided into four parts: a "heel", a "bow", a "metatarsal", and a "toe". Therefore, it is presumed that the floor reaction force can be measured with high accuracy by arranging at least one sensor in each of the four divided parts.
Therefore, in the present invention, at least four pressure sensors are provided in at least four places on the footwear, specifically, at least four places of the "heel", the "bow", the "metatarsal", and the "toe". Shall be provided. When higher measurement accuracy is required, it is preferable to provide at five or more locations. However, even if seven or more locations are provided, improvement in accuracy cannot be expected very much, so it is preferable to set within four to six locations.
[0019]
In the system according to the present invention, as described above, the position of the knee joint and / or the hip joint of the subject while walking is obtained after estimating the floor reaction force and the ankle joint moment of the subject while walking with the pressure sensor. In this case, one of the following two types of means is used.
First, the first means will be described.
The first means comprises an angle measuring sensor (4) attached to the footwear (1) and measuring an ankle angle of the subject during walking, and a joint position estimating means provided in the analyzing device (20). The joint position estimating means estimates a knee position and / or a hip position of the subject during walking based on the ankle angle of the subject measured by the angle measurement sensor (4). Alternatively, the angle of the knee joint may be measured by the ankle and the sensor (4).
The angle measurement sensor (4) is not particularly limited, but for example, a goniometer can be used.
The estimation of the knee joint position and / or the hip joint position by the joint position estimating means is performed by measuring the body shape (eg, the length of the foot) of the subject in advance, and measuring the measured ankle angle with respect to the skeleton model that matches the body shape. Can be performed by applying
[0020]
The second means is a joint position measuring means for photographing the movement of the foot of the subject during walking with a CCD camera (5) and performing signal processing to measure the knee joint position and / or hip position of the subject during walking. Become.
The measurement by the measuring means is performed by attaching a marker to a specific position such as a knee or a hip joint of the subject, and capturing the locus of the spherical marker using a camera to observe the movement of the foot during walking of the subject.
In this measurement, in order for the camera to accurately capture the movement of the subject's knees and hip joints, for example, a CCD camera is attached to a wheeled cart or the like having an extension to the side of the subject, and the subject mounts the cart. By pushing and walking, it is preferable that the camera can capture the movement of the subject's foot while moving from the side at the same speed as the subject. Further, in the method of measuring three-dimensional motion from information of a plurality of cameras which has been conventionally used, a space tends to be large. Therefore, one camera and an image of a cross section or a diameter as an image of a marker are often used. Using a method that estimates the direction of the marker and the distance to the marker from information related to the size and the position of the marker in the image, and estimates the three-dimensional position of the marker from that information, enables measurement in a small space. It becomes.
[0021]
The data of the knee joint position and / or the hip joint position of the subject during walking obtained by using any of the above two means is input to the analysis device (20).
The analysis device (20) uses the position data of each joint (ankle joint, knee joint, hip joint) and the above-described estimated value of the floor reaction force to estimate the moment of each joint during walking of the subject. Estimating means and muscle tension estimating means for estimating the muscle tension of the subject from the obtained joint moment estimated value are provided, and these means estimate the moment and muscle tension of the knee joint and hip joint. As for the position of the ankle joint, the relative position between the pressure sensor and the ankle is known as described above, so that it is not necessary to separately estimate the position of the knee joint or the hip joint.
[0022]
Hereinafter, a method of estimating joint moment and muscle tension by the analysis device (20) will be specifically described.
In the estimation, a musculoskeletal model as shown in FIG. 6 is used.
The musculoskeletal model includes nine dominant muscles (1) rectus femoris, (2) gluteus maximus, (3) hamstring, (4) wide muscle, (5) thigh 2 when driving lower limb joints. (Head short muscle, (6) gastrocnemius, (7) soleus, (8) anterior tibialis, (9) iliopsoas).
This method is a method of estimating the tension applied to each of the nine muscles at a certain time t from floor reaction force data, position data of each joint of a lower limb, and parameters of a human body.
[0023]
Hereinafter, details of the estimation method will be described step by step.
(1) The moment generated at each joint is calculated from the following equation 1 (Equation 1) based on the floor reaction force data, the joint position data, and the parameter 1 of the human body.
(Equation 1)

Here, the subscript 1 indicates an ankle joint, 2 indicates a knee joint, and 3 indicates a hip joint. I ₁ , I ₂ , and I ₃ are the moments of inertia of the ankle joint, the knee joint, and the hip joint, respectively, and m ₁ , m ₂ , and m ₃ are the feet (parts beyond the ankle), the lower leg, and the thigh, respectively. Mass, x _g1 , y _g1 represent the center of mass of the foot, x _g2 , y _g2 represent the center of mass of the lower leg, and x _g3 , y _g3 represent the center of mass of the thigh. These are collectively referred to as the human body. It is called parameter 1. N _x and N _y are the vertical and horizontal components of the floor reaction force, respectively, and x ₀ and y ₀ are the origin coordinates fixed at an arbitrary position.
[0024]
(2) The moment obtained by multiplying the tension of the muscle by the moment arm and adding them in consideration of the sign is the moment of each joint generated by the muscle, the following equation (2) holds.
(Equation 2)

[0025]
(3) By substituting each joint moment calculated by Equation 1 into Equation 2, three equations can be obtained. Since the moment arm is known, these three equations are nine muscle tension (unknown) equations.
(4) Since nine unknowns cannot be generally obtained from only three equations, nine unknowns (muscle tension) are set so as to satisfy the three equations and minimize the evaluation function E shown in the following equation (3). Ask.
[Equation 3]

_{Here, F i max} is the maximum muscle tension of each muscle.
The maximum muscle tension of each muscle is obtained by the following equation.
F _{i max} = f _j PCSA _j
Here, PCSA _j is the physiological cross-sectional area of the muscle, and f _j is a function related to the contraction speed of the muscle and the amount of elongation / contraction of the muscle.
[0026]
By the above method, the joint moment and muscle tension of the lower limb can be obtained, and it has been confirmed that the pattern of the muscle tension thus obtained and the pattern of the myoelectric potential match well.
[0027]
In the system according to the present invention, the lower limb joint moment and the muscle tension of the subject during walking can be easily and inexpensively estimated in a small space without burdening the subject by the above-described method.
[0028]
【The invention's effect】
As described above, according to the system using the floor reaction force estimating device according to the present invention, a load is applied to the body of the subject, as in a conventional method, for example, a method of attaching electrodes to the subject and measuring myoelectric potential. The lower limb joint moment and muscle tension of the subject without the need for space and the need for expensive equipment, unlike the method of combining a three-dimensional motion analysis system with multiple floor reaction force meters. Can be easily and accurately grasped.
Therefore, information for the instructor to determine what kind of rehabilitation is effective for the patient at the site of walking rehabilitation, and information on which part of the muscles should be focused on in training the athlete, etc. are acquired. This is an extremely effective method.
[Brief description of the drawings]
FIG. 1 is a block diagram schematically showing an overall configuration of a lower limb joint moment and lower limb muscle tension estimating system according to the present invention.
FIG. 2 is an external view showing a sole pressure measuring device according to the present invention.
FIG. 3 is a back view of an underlay sheet to which a pressure sensor is attached.
FIG. 4 is a diagram showing a state in a sagittal plane of a force applied to a foot during a standing phase.
FIG. 5 is a table showing regression coefficients and partial regression coefficients derived by multiple regression analysis.
FIG. 6 is a diagram illustrating an example of a musculoskeletal model.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Footwear 2 Pressure sensor 3 Underlay sheet 4 Ankle angle measuring sensor 5 Camera 10 Sole pressure measuring device 20 Analyzer K Heel P Chopard joint MP 1st MP joint Q 4th MP joint ML Thumb U U 3rd toe

Claims (7)

An apparatus for estimating a floor reaction force from a pressure applied to a sole during walking of a subject, the apparatus reacting to footwear for the subject to walk while walking and a floor reaction force such as a pressure sensor disposed on the surface of the footwear. A floor reaction force estimating device, comprising: a sensor that performs measurement; and an analyzing device that analyzes a measurement value of the sensor, wherein the sensor is disposed at least at four or more locations on the surface of the shoe. The floor reaction force estimating device according to claim 1, wherein the sensor is disposed at least at a portion corresponding to a heel, an ankle, a metatarsal, and a toe of a subject's foot. A sole for measuring the pressure applied to the sole during walking of the subject, the sole comprising: footwear for walking while the subject wears the footwear; A floor reaction force estimating means for estimating at least a vertical floor reaction force applied to the sole of the subject during walking from the measurement values, the analysis device comprising: An estimation system for a lower limb joint using a sole pressure, comprising: an ankle moment estimation means for estimating an ankle moment during walking of a subject from a measured value. The floor reaction force estimating means of the analysis device obtains a vertical floor reaction force and a horizontal floor reaction force applied to the sole of the subject during walking from the measurement value of the sole pressure measurement device. The system for estimating a lower limb joint moment using a sole pressure according to claim 3. An angle measuring sensor attached to the footwear to measure an ankle angle of the subject during walking, wherein the analyzing device detects the knee position and / or hip joint of the subject during walking based on the measurement value of the angle measuring sensor. Using a joint position estimating means for estimating a position, an estimated value of the knee joint position and / or hip position estimated by the joint position estimating means, and the estimated value of the floor reaction force, a lower limb joint moment of the subject during walking is calculated. The system for estimating a lower limb joint moment using a sole pressure according to claim 4, further comprising a joint moment estimating means for estimating the joint moment. The apparatus is provided with joint position measuring means for measuring a knee joint position and / or a hip joint position of the subject during walking by photographing the movement of the foot of the subject during walking with a CCD camera and performing signal processing. Joint moment estimating means for estimating a knee joint and / or hip moment of a subject during walking using data of the knee joint position and / or hip position measured by the joint position measuring means and the estimated value of the floor reaction force. The system for estimating a lower limb joint moment using a sole pressure according to claim 4, characterized in that: A lower limb muscle tension estimating system using sole pressure, comprising: a muscle tension estimating means for estimating a subject's muscle tension by applying an estimated value obtained by the joint moment estimating means to a musculoskeletal model.

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