JP2018038656A - Joint torque computing system, cycle computer, and joint torque measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joint torque computing system, a cycle computer and a joint torque measuring method materializing downsizing and measuring a joint torque of lower extremities in a short time.SOLUTION: A joint torque computing system 10 includes a first detection part 11, a second detection part 12, and an arithmetic processing part 14. The arithmetic processing part 14 calculates second joint position information of a knee joint on the basis of rotation position information of a crank 31 acquired from the first detection part 11, length information from a hip joint to the knee joint, length information from the knee joint to an ankle joint, length information from the ankle joint to a pedal shaft 32, first joint position information of the ankle joint, and third joint position information of the hip joint. The arithmetic processing part 14 performs arithmetic processing by inverse dynamics analysis on the basis of tread force information applied to a pedal 33, acquired from the second detection part 12, and one information out of the first, second, and third joint position information, and calculates a joint torque of one joint out of the ankle, knee, and hip joints.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a joint torque calculation system, a cycle computer, and a joint torque measurement method.

Patent Document 1 below discloses a feedback estimation method and apparatus for joint force and joint moment. This estimation method and apparatus are used in the biomechanics field for analyzing human and animal movements based on inverse dynamics. For example, the estimation method and apparatus can estimate the joint torque and force between joints of humans and animals.
Patent Document 2 below discloses musculoskeletal modeling using finite element analysis, process integration, and design optimization. In the disclosed technique, motion data is generated from motion capture data, and an inverse dynamic analysis of the musculoskeletal model is performed from the motion data.

On the other hand, the following Patent Document 3 discloses a pedaling state measuring device. This apparatus can calculate an evaluation index for pedaling skills of a bicycle.
Similarly, regarding a bicycle, Patent Literature 4 below discloses a muscle fatigue determination device, a muscle fatigue determination method, and a muscle fatigue determination program. With this disclosed technique, muscle fatigue information during pedaling of a bicycle can be generated in real time.
Patent Document 5 below discloses a measurement system and method for analyzing the motion trajectory of a knee joint during bicycle cycling.

Japanese Patent No. 4264345 Japanese Unexamined Patent Publication No. 2015-011714 JP 2014-008789 A JP 2006-107093 A Japanese Patent Laying-Open No. 2015-091311

There are a plurality of methods for estimating the joint position of the lower limb of the rider (human) during the pedaling operation of the bicycle as disclosed in each of Patent Documents 3 to 5. However, estimation of the joint position requires a large-scale device such as a motion capture system and takes time.
On the other hand, when a commercially available cycle computer and sensors are mounted on the bicycle, pedaling operations are detected by the sensors, and various types of detected information are displayed on the display screen of the cycle computer. Here, the various information is information such as travel distance, integrated distance, travel speed, cadence, heart rate, calorie consumption, and the like. However, there is no technique for estimating the joint torque of the lower limbs using the sensors.

  In consideration of the above-described facts, the present invention can realize a reduction in size with a simple configuration, and can measure a joint torque of a lower limb joint in a short time, a cycle computer, and a joint torque Provides a measurement method.

The joint torque calculation system according to the first aspect of the present invention includes:
A first detector connected to one end of the crankshaft of the bicycle and detecting a rotational position of a crank that rotates about the crankshaft;
A second detector for detecting a pedal force acting on a pedal connected to the other end of the crank via a crankshaft;
Rotational position information acquired from the first detector, first length information from the hip joint to the knee joint, second length information from the knee joint to the ankle joint, and third length information from the ankle joint to the pedal shaft And the second joint position information of the knee based on the first joint position information of the ankle joint and the third joint position information of the hip joint, the pedaling force information acquired from the second detection unit, and the first joint Based on at least one of the position information, the second joint position information, and the third joint position information, a calculation process by inverse dynamics analysis is performed, and the joint torque of at least one of the ankle joint, the knee joint, and the hip joint is calculated. An arithmetic processing unit to calculate,
Is provided.

  The joint torque calculation system according to the first aspect includes a first detection unit, a second detection unit, and a calculation processing unit. The first detector is connected at one end to the crankshaft of the bicycle and detects the rotational position of the crank that rotates about the crankshaft. A 2nd detection part detects the pedal effort which acts on the pedal connected with the other end part of the crank via the pedal shaft.

The arithmetic processing unit includes the rotational position information acquired from the first detection unit, the first length information to the third length information, the first joint position information of the ankle joint, and the third joint position information of the hip joint. Based on this, the second joint position information of the knee joint is calculated.
Here, the rotational position information is also rotational position information of a pedal shaft that rotates about the crankshaft via the crank. The first length information is the length information from the hip joint to the knee joint, the second length information is the length information from the knee joint to the ankle joint, and the third length information is the length information from the ankle joint to the pedal shaft. is there. The length value of the first length information, the length value of the second length information, and the length value of the third length information are each constant. The third joint position information is position information of the hip joint whose position is fixed.
The first joint position information is position information of the ankle joint, and fluctuates with a change in the posture angle of the pedal. The first joint position information is acquired as, for example, an initial value, or is acquired from an actual measurement value of the pedal posture angle.
The arithmetic processing unit can easily calculate the second joint position information by geometric calculation based on the first joint position information.

When the second joint position information is calculated by geometric calculation, the first joint position information, the second joint position information, and the third joint position information are all specified. In the arithmetic processing unit, based on at least one information of the first joint position information, the second joint position information, and the third joint position information, and the pedaling force information acquired from the second detection unit, an inverse dynamic analysis (musculoskeletal) (Case analysis) is performed.
Accordingly, the arithmetic processing unit calculates joint torque (joint burden) of at least one of the ankle joint, the knee joint, and the hip joint by a simple arithmetic processing without using a large-scale device such as a motion capture system. Can do.

  The joint torque calculation system according to the second aspect of the present invention is the information input unit for inputting at least the first length information, the second length information, and the third length information in the joint torque calculation system according to the first embodiment. And an information output unit that outputs at least a calculation result of the joint torque.

The joint torque calculation system according to the second aspect includes an information input unit and an information output unit. Since at least the first length information, the second length information, and the third length information are input to the information input unit, the second joint position information can be calculated in the arithmetic processing unit by this input.
The information output unit outputs at least the calculation result of the joint torque calculated by the arithmetic processing unit. For example, when the information output unit is equipped with a display function, the user can check the calculation result of the joint torque.

  In the joint torque calculation system according to the third aspect of the present invention, the joint torque calculation system according to the second embodiment further includes a third detection unit that detects a posture angle of the pedal on the pedal shaft, At least one of the first joint position information and the pedal effort information is generated using the acquired angle information.

  The joint torque calculation system according to the third aspect further includes a third detection unit. The third detection unit detects the posture angle of the pedal on the pedal shaft. When the posture angle information is acquired, the arithmetic processing unit can calculate the first joint position information based on the posture angle information and the third length information from the ankle joint to the pedal shaft. For this reason, since the first joint position information can be calculated in real time based on the attitude angle information acquired from the third detection unit, the joint torque can also be calculated in real time.

  In the joint torque calculation system, the first joint position information may be generated based on actual measurement of the joint position of the ankle joint. In this case, since the first joint position information is generated based on the actual measurement of the joint position of the ankle, additional devices such as sensors are eliminated. For example, the third length information from the ankle joint to the pedal shaft is measured using a measure, and this measurement value is used as the first joint position information.

  Furthermore, as the first joint position information, for example, joint position information averaged for each skill level of the user who performs the pedaling operation, for each physique of the user, and the database can be used. Then, the first joint position information is input from the information input unit. For this reason, since there is no additional device, the joint torque calculation system can be further reduced in size.

  In the joint torque calculation system according to the fourth aspect of the present invention, in the joint torque calculation system according to the second aspect or the third aspect, the calculation processing unit is configured to determine the crankshaft of the joint based on the joint torque and the rotational position information. A physical quantity per predetermined rotation angle is calculated, and the magnitude of the physical quantity with respect to the threshold is determined.

In the joint torque calculation system according to the fourth aspect, the calculation processing unit calculates a physical quantity and determines the magnitude of the physical quantity with respect to the threshold value. The physical quantity is calculated as a physical quantity at the joint per predetermined rotation angle of the crankshaft based on the joint torque and the rotational position information. The threshold is arbitrarily set.
For this reason, as a result of determining the magnitude of the physical quantity, for example, the pedaling performance of the user can be measured. Furthermore, based on the measurement result of pedaling performance, the user can confirm the operation state such as positioning and pedaling. Also, a third party can propose an ideal operation state to the user.

  In the joint torque calculation system according to the fifth aspect of the present invention, in the joint torque calculation system according to the fourth aspect, the physical quantity is a joint power derived based on the joint torque and the angular velocity of the joint.

  In the joint torque calculation system according to the fifth aspect, since the physical quantity is the joint power derived based on the joint torque and the angular velocity of the joint, the user's pedaling performance can be quantified.

  In the joint torque calculation system according to the sixth aspect of the present invention, in the joint torque calculation system according to the fifth aspect, the information output unit outputs the joint power.

  In the joint torque calculation system according to the sixth aspect, since the joint power is output from the information output unit, the user can check the joint power.

  In the joint torque calculation system according to the seventh aspect of the present invention, in the joint torque calculation system according to the second aspect or the sixth aspect, the rotational position information is acquired in real time from the first detection unit, and the pedal effort information is acquired from the second detection unit. The calculation processing unit calculates the joint torque in real time, and the information output unit outputs the joint torque in real time.

  In the joint torque calculation system according to the seventh aspect, the joint torque is calculated in real time by the calculation processing unit and output in real time by the information output unit. Therefore, for example, the user can check the joint torque in real time.

  In the joint torque calculation system according to the eighth aspect of the present invention, in the joint torque calculation system according to the sixth aspect, the rotational position information is acquired from the first detection unit in real time, and the treading force information is acquired from the second detection unit in real time. The arithmetic processing unit calculates joint torque and joint power in real time, and the information output unit outputs at least joint power in real time.

  In the joint torque calculation system according to the eighth aspect, the joint torque and the joint power are calculated in real time by the calculation processing unit, and at least the joint power is output in real time by the information output unit. For this reason, for example, the user can confirm at least the joint power in real time.

  In the cycle computer according to the ninth aspect of the present invention, the calculation processing unit of the joint torque calculation system according to any one of the first to eighth aspects is built in the housing.

  In the cycle computer according to the ninth aspect, the arithmetic processing unit is built in the housing. Since the cycle computer is mounted compactly on, for example, a bicycle, the user can check the pedaling performance by calculating joint torque and joint power while the bicycle is running.

The method for measuring joint torque according to the tenth aspect of the present invention comprises:
One end is connected to the crankshaft of the bicycle, and the rotational position of the crank that rotates around the crankshaft is detected to obtain rotational position information,
Detecting pedaling force acting on a pedal connected to the other end of the crank via a pedal shaft to obtain pedaling force information;
Obtaining first length information from the hip joint to the knee joint, second length information from the knee joint to the ankle joint, and third length information from the ankle joint to the pedal shaft;
Obtaining the first joint position information of the ankle joint and the third joint position information of the hip joint;
Based on the rotational position information, the first joint position information, and the third joint position information, the second joint position information of the knee joint is calculated,
Based on the pedaling force information and at least one information of the first joint position information, the second joint position information, and the third joint position information, a calculation process by inverse dynamics analysis is performed, and at least the ankle joint, the knee joint, and the hip joint Calculate the joint torque of one joint.

In the joint torque measurement method according to the tenth aspect, the rotational position of the crank that rotates about the crankshaft of the bicycle is detected, and rotational position information is acquired. On the other hand, the pedal effort applied to the pedal connected to the crankshaft via the crank is detected, and the pedal effort information is acquired. Further, the first length information to the third length information, the first joint position information of the ankle joint, and the third joint position information of the hip joint are acquired.
Here, the rotational position information is also rotational position information of a pedal shaft that rotates about the crankshaft via the crank. The first length information is the length information from the hip joint to the knee joint, the second length information is the length information from the knee joint to the ankle joint, and the third length information is the length information from the ankle joint to the pedal shaft. is there. The length value of the first length information, the length value of the second length information, and the length value of the third length information are each constant. The third joint position information is position information of the hip joint whose position is fixed.
The first joint position information is position information of the ankle joint, and fluctuates with a change in the posture angle of the pedal. The first joint position information is acquired as, for example, an initial value, or is acquired from an actual measurement value of the pedal posture angle.
Based on the first joint position information, the second joint position information can be easily calculated by geometric calculation.

When the second joint position information is calculated by geometric calculation, the first joint position information, the second joint position information, and the third joint position information are all specified. Based on at least one of the first joint position information, the second joint position information, and the third joint position information, and the pedaling force information acquired from the second detection unit, a calculation process based on inverse dynamics analysis is performed.
Accordingly, at least one joint torque of the ankle joint, the knee joint, and the hip joint can be calculated by a simple calculation process without using a large-scale device such as a motion capture system.

  The joint torque measurement method according to the eleventh aspect of the present invention is the joint torque measurement method according to the tenth aspect, wherein the physical quantity per predetermined rotation angle of the crankshaft in the joint is based on the joint torque and the rotational position information. And the magnitude of the physical quantity with respect to the threshold is determined.

In the joint torque measurement method according to the eleventh aspect, the physical quantity is calculated, and the magnitude of the physical quantity with respect to the threshold is determined. The physical quantity is calculated as a physical quantity at the joint per predetermined rotation angle of the crankshaft based on the joint torque and the rotational position information. The threshold is arbitrarily set.
For this reason, as a result of determining the magnitude of the physical quantity, for example, the pedaling performance of the user can be measured. Furthermore, based on the measurement result of pedaling performance, the user can confirm the operation state such as positioning and pedaling. Also, a third party can propose an ideal operation state to the user.

  According to the present invention, there is provided a joint torque calculation system, a cycle computer, and a joint torque measuring method capable of realizing downsizing with a simple configuration and measuring the joint torque of a lower limb joint in a short time. Can be provided.

1 is a schematic configuration diagram of a joint torque calculation system according to an embodiment of the present invention and a bicycle to which the joint torque calculation system is applied. FIG. 2 is a system block diagram of the joint torque calculation system shown in FIG. 1. FIG. 2 is a perspective view of a cycle computer including a calculation processing unit of the joint torque calculation system shown in FIG. 1. It is a schematic diagram which shows the joint positional relationship of a user's leg in the state in which the user got on the bicycle to which the joint torque calculation system shown in FIG. 1 is applied. It is a schematic diagram of the principal part which shows the joint positional relationship of the ankle shown by FIG. 4 in a pedal coordinate system. It is a flowchart explaining the measuring method of the joint torque using the joint torque calculation system which concerns on embodiment. It is a schematic diagram which shows the joint positional relationship of a user's lower leg for every fixed angle of a crank in the state where the user got on the bicycle to which the joint torque calculation system shown in FIG. 1 is applied. It is a measurement figure explaining the treading force information acquired by the 2nd detection part in the joint torque calculation system shown by FIGS. It is a schematic diagram which shows the user's leg corresponding to FIG. 4 explaining the generation source of joint power. (A) is a figure which shows the calculation result of the knee joint torque using the joint torque calculation system which concerns on embodiment, (B) is a figure which shows the calculation result of a hip joint torque. (A) is a figure which shows the calculation result of the knee joint torque using the system which concerns on a comparative example, (B) is a figure which shows the calculation result of a hip joint torque. (A) is a figure which shows the calculation result of the hip joint torque using the joint torque calculation system which concerns on embodiment, (B) is a figure which shows the calculation result of the angular velocity of a hip joint, (C) shows the calculation result of hip joint power. FIG. It is a graph which shows the calculation result of the ratio of each joint power using the joint torque calculation system which concerns on embodiment.

  Hereinafter, a joint torque calculation system, a cycle computer, and a joint torque measurement method according to an embodiment of the present invention will be described with reference to FIGS. Here, in the drawing, the arrow X, arrow Y, and arrow Z that are shown are directions that coincide with the X, Y, and Z axes of the three-dimensional coordinates. Note that the application direction of the present embodiment is not limited.

[Configuration of joint torque calculation system]
(1) Configuration of Bicycle As shown in FIG. 1, a joint torque calculation system 10 according to the present embodiment is applied to a bicycle 20 and is attached to the bicycle 20. The bicycle 20 includes a frame 21 as a skeleton member. The frame 21 is assembled by connecting the top tube 211, the down tube 212, and the seat tube 213 in a substantially triangular shape in a side view, and connecting the seat tube 213, the seat stay 214, and the chain stay 215 in a triangular shape in a side view. It has been. A saddle 22 is attached to the upper portion of the seat tube 213 via a seat post 221 whose height can be adjusted.

  A head tube 23 extending in the vertical direction is connected to the front portion of the frame 21. A handle bar 24 that is rotatable about the axis of the head tube 23 is attached to the upper portion of the head tube 23, and handle grips 241 are provided at both ends of the handle bar 24. One end of a pair of left and right front forks 25 extending in the vertical direction is connected to the lower portion of the head tube 23. A front wheel 26 having a tire 261 mounted on the outer peripheral portion is attached to the other end of the front fork 25. The front wheel 26 is rotatable about the Y axis.

  On the other hand, a rear wheel 28 having a tire 281 mounted on the outer peripheral portion is attached to the rear portion of the frame 21 via a rear gear 27. As with the front wheel 26, the rear wheel 28 is rotatable about the Y axis.

  A front gear 29 is attached to a connecting portion of the down tube 212, the seat tube 213, and the chain stay 215 of the frame 21. The front gear 29 is connected to a crankshaft 30 having the Y-axis direction as the rotation axis direction, and the crankshaft 30 is configured to rotate around the Y-axis in the direction of arrow A about the Y-axis. One end of a crank (crank arm) 31 is connected to the crankshaft 30. A pair of left and right cranks 31 are provided at both ends of the crankshaft 30. One crank 31 is attached to the other crank 31 at a position that is inverted 180 degrees about the crankshaft 30. A pedal shaft 32 is connected to the other end of the crank 31, and a pedal 33 is attached to the pedal shaft 32 so as to be rotatable (or rotatable) in the direction of arrow B.

  A chain 34 is wound between the front gear 29 and the rear gear 27. That is, when the pedaling force of the user 40 is input to the pedal 33, the pedaling force is transmitted to the crankshaft 30 via the pedal shaft 32 and the crank 31 as a rotational force that rotates the crankshaft 30. The rotational force is transmitted to the rear wheel 28 via the front gear 29, the chain 34, and the rear gear 27, and becomes a driving force for running the bicycle 20.

(2) User As shown in FIG. 1, a user 40 rides on the bicycle 20, and the user 40 operates the bicycle 20 to run. Here, the user 40 is a human. In general, in inverse dynamics analysis (musculoskeletal analysis), an object including two or more natural number N links (segments) S and N-1 joints (joints) J that can be regarded as rigid bodies ( The user 40 can be expressed as a measurement object.

More specifically, for example, a human head is expressed as a link S1, and a torso and a waist are expressed as links S2 and S3, respectively. The upper right arm, right forearm, and right hand are represented as links S4, S5, and S6, and the left upper arm, left forearm, and left hand are represented as links S7, S8, and S9, respectively. The right thigh, right lower leg, and right foot are represented as links S10, S11, and S12, and the left thigh, left lower leg, and left foot are represented as links S13, S14, and S15, respectively. That is, the object has 15 (= N) links S1 to S15.
The order of the links S1 to S15 is arranged for convenience in order to simplify the description.

On the other hand, each of link S1 and link S2 is connected by joint J1, and each of link S2 and link S3 is connected by joint J2. Each of the links S2 and S4 is connected by a joint J3, each of the links S4 and S5 is connected by a joint J4, and each of the links S5 and S6 is connected by a joint J5. Each of the links S2 and S7 is connected by a joint J6, each of the links S7 and S8 is connected by a joint J7, and each of the links S8 and S9 is connected by a joint J8.
Similarly, each of the link S3 and the link S10 (hereinafter also referred to as “right thigh S10”) is connected by a joint J9 (hereinafter also referred to as “right hip joint J9”). Each of the link S10 and the link S11 (hereinafter sometimes referred to as “right lower leg S11”) is connected by a joint J10 (hereinafter also referred to as “right knee joint J10”). Each of the link S11 and the link S12 (hereinafter sometimes referred to as “right foot S12”) is connected by a joint J11 (hereinafter sometimes referred to as “right ankle joint J11”).
Further, each of the links S3 and S13 is connected by a joint (left hip joint) J12, each of the links S13 and S14 is connected by a joint (left knee joint) J13, and each of the links S14 and S15 is a joint (left foot). Neck joints) are connected by J14. That is, the object has 14 (= N−1) joints J1 to J14.
The order of the joints J1 to J14 is similarly arranged for convenience.

  Here, all the links S1 to S15 each have three positional degrees of freedom and three speed degrees of freedom in a three-dimensional coordinate system including the X axis, the Y axis, and the Z axis. That is, all the links S1 to S15 have a total of six degrees of freedom. Similarly, all the joints J1 to J14 have a total of six degrees of freedom.

(3) Specific Configuration of Joint Torque Calculation System As shown in FIGS. 1 and 2, the joint torque calculation system 10 includes a first detection unit 11, a second detection unit 12, a third detection unit 13, And an arithmetic processing unit 14. Further, the joint torque calculation system 10 includes an information input unit 15, an information output unit 16, and a power source 17.

The first detector 11 is mounted on, for example, a front gear 29, and a magnetic or optical rotation (rotation number) detection sensor is used for the first detector 11. The first detector 11 can detect the rotational position of the crank 31 that rotates about the crankshaft 30. The rotation position of the crank 31 is detected because the length of the crank 31 in the longitudinal direction, specifically, the dimension from the center of the crankshaft 30 to the center of the pedal shaft 32 is known. Means detection.
The second detection unit 12 is attached to the pedal shaft 32, and a pedal force detection sensor (pedal force meter) is used for the second detection unit 12. The second detection unit 12 detects the magnitude of the pedal force acting on the pedal shaft 32 from the lower limb of the user 40 via the pedal 33 or the magnitude and direction in a two-dimensional coordinate system including at least the X axis and the Z axis. be able to. Further, a pressure sensor attached to the pedal 33 can be used for the second detection unit 12.
The third detection unit 13 is mounted on either the pedal 33 or the pedal shaft 32, and an inertial sensor is used for the third detection unit 13, for example. The third detection unit 13 can detect the posture angle (tilt angle) of the pedal 33 with respect to the pedal shaft 32.

In the present embodiment, the arithmetic processing unit 14 calculates the joint torque of at least one of the right hip joint J9, the right knee joint J10, and the right ankle joint J11 of the lower limb of the user 40. The arithmetic processing unit 14 is constructed by, for example, a microprocessor including at least a central processing unit (CPU) and a storage device.
Since the motion of the user (human) 40 is generated by rotating the joint J, the joint torque (joint moment) is a joint burden, which is a physical quantity indicating the joint burden. The calculation method of the joint torque in the arithmetic processing unit 14 will be described later.

  Similarly, the arithmetic processing unit 14 calculates the joint torque of at least one of the joint (left hip joint) J12, the joint (left knee joint) J13, and the joint (left ankle joint) J14. Since the joint torque calculation method is the same for the left and right, the present embodiment describes a method for calculating the joint torque of the right hip joint J9, right knee joint J10, and right ankle joint J11 on the right side of the lower limb, and the left joint J12. -Description of the calculation method of the joint torque of the joint J14 is omitted.

  Further, the arithmetic processing unit 14 calculates the joint power of at least one of the right hip joint J9, the right knee joint J10, and the right ankle joint J11 on the right side of the lower limb, and at least the joints J12 to J14 on the left side of the lower limb. The joint power of one joint is calculated. Here, the joint power is defined by the product of the joint torque of the joint and the angular velocity of the joint (joint power = joint torque × angular velocity). The calculation method of the joint power in the arithmetic processing unit 14 will be described later.

The information input unit 15 receives at least information necessary for calculating the joint torque. For example, as shown in FIG. 4, the information input unit 15 includes the length L _f of the right thigh S10 from the right hip joint J9 to the right knee joint J10 as the first length information, and the second length information. The length L _l of the right lower leg S11 from the right knee joint J10 to the right ankle joint J11 is input.
In addition, the information input unit 15 receives the length L _ap from the right ankle joint J11 to the center position of the pedal shaft 32 as the third length information. These first length information to third length information are obtained by measuring in advance using a measuring instrument when calculating the joint torque. The first length information to the third length information are input to the information input unit 15 as “user model information” and registered (stored) in a storage device (not shown) of the joint torque calculation system 10.

  Furthermore, the joint position of the right hip joint J9 is input to the information input unit 15 as third joint position information. Since the user 40 sits on the saddle 22 and operates the bicycle 20, the joint position of the right hip joint J9 is handled as a fixed value. Specifically, the geometry of the position of the saddle 22 of the bicycle 20 is measured. For example, the position of 30 mm upward from the upper surface of the saddle 22 at the front and rear intermediate position and the left and right intermediate position of the saddle 22 is the joint of the right hip joint J9. It is assumed to be a position. The third joint position information is input to the information input unit 15 as “user model information” and registered in the storage device of the joint torque calculation system 10.

Further, the joint torque calculation system 10 is configured to include the third detection unit 13 to detect the posture angle of the pedal 33, and based on this posture angle information, the joint position of the right ankle joint J11 is the first joint position information. It is set as the structure calculated as.
On the other hand, instead of the configuration of the third detection unit 13 or in combination with the third detection unit 13, in the joint torque calculation system 10, the first joint position information of the right ankle joint J <b> 11 is input from the information input unit 15. It may be configured as follows. Specifically, first joint position information that is measured using a measuring instrument in advance when calculating the joint torque, is determined by diagnosis for each type of the user 40, and is stored in a database is used.
Here, the type of the user 40 is classified into, for example, a professional road racer level advanced person, an amateur road racer level intermediate person, an advanced person, and a general level beginner other than the intermediate person. When the first joint position information in the database is input as “user model information” from the information input unit 15, it is registered in the storage device of the joint torque calculation system 10.

  1 and 2, the information output unit 16 is configured to include a display device, more specifically, a liquid crystal display or an organic electroluminescence display. . The information output unit 16 is preferably a touch sensor type display device that allows the user 40 to input various information by touching the display and can be used as part of the information input unit 15. The information output unit 16 is configured to display information on at least one of joint torque and joint power calculated by the arithmetic processing unit 14. As a display method, for example, any one of a method of displaying numerical values of joint torque and joint power, and a method of displaying symbols and graphs indicating the magnitudes of joint torque and joint power are employed.

  The first detection unit 11, the second detection unit 12, the third detection unit 13, the arithmetic processing unit 14, the information input unit 15, and the information output unit 16 are each connected to a bus wiring 18. Here, the bus wiring 18 includes one or both of wire such as a cable, and wireless using the international standard IEEE 802.11 standard, IEEE 802.15.1 standard, or the like.

  The power source 17 supplies power to each of the first detection unit 11, the second detection unit 12, the third detection unit 13, the calculation processing unit 14, the information input unit 15, and the information output unit 16. Make it work. For the power source 17, either one or both of a primary battery and a secondary battery are used. The power supply 17 supplies power to the first detection unit 11, the second detection unit 12, and the third detection unit 13, and supplies power to the arithmetic processing unit 14, the information input unit 15, and the information output unit 16. It is good also as a several system with a power supply.

(4) Configuration of Cycle Computer As shown in FIGS. 1 and 3, the cycle computer 19 is attached to the handlebar 24 of the bicycle 20. The cycle computer 19 is a resin-made or light metal hollow hexahedron that is smaller in the height direction (Z-axis direction) than the front-rear direction (X-axis direction) and the left-right direction (Y-axis direction). The housing 190 is provided. The casing 190 incorporates the calculation processing unit 14 of the joint torque calculation system 10 and further includes a power supply 17. A touch sensor type display device that occupies most of the area and is used as each of the information input unit 15 and the information output unit 16 is disposed on the upper surface portion of the housing 190.

  The information output unit 16 shown in FIG. 3 can display at least one information of joint torque and joint power by selecting the menu mode. In addition, the information output unit 16 can display one or more of various information such as travel distance, integrated distance, travel speed, date and time, temperature, humidity, lap time, cadence, heart rate, calorie consumption, and the like. . The information output unit 16 can display a plurality of information at a time.

  On the right side surface of the casing 190 of the cycle computer 19, a power switch 191 for operating the cycle computer 19 (joint torque calculation system 10) to start and stop, and a lap time operation switch 192 are disposed. A menu mode selection switch 193 is disposed on the left side of the housing 190.

  Although not shown, the cycle computer 19 is provided with an interface that can be connected to an external device. Here, the external device is a personal computer, an external monitor, an external printer, or the like. Since the interface is provided, various information can be input from the personal computer to the cycle computer 19 via the interface, for example. Various information can be output to a personal computer, an external monitor, or an external printer via an interface.

[Measuring method of joint torque]
A method for measuring the joint torque using the joint torque calculation system 10 is as follows. In the joint torque measurement method, the joint power is measured after the joint torque is measured.

In the joint torque measurement method, as shown in FIG. 4, the lower limb of the user 40 is handled as a two-dimensional model including the X axis and the Z axis. Here, the relative position between the center position of the crankshaft 30 of the bicycle 20 and the joint position of the right hip joint J9 of the lower limb (joint center position, the same applies hereinafter) is always the same, and from the crankshaft 30 to the right hip joint J9. It is assumed that the length L _hc is constant. By measurement, the joint position of the right hip joint J9 is specified, and the third joint position information is acquired as shown in FIG. 6 (S50). The third joint position information is input from the information input unit 15 of the joint torque calculation system 10 (see FIGS. 1 to 3).

As shown in FIG. 4, it is assumed that the length L _f of the right thigh S10 of the lower limb, the length L _l of the right lower leg S11, and the length L _ap from the right ankle joint J11 to the pedal shaft 32 are constant. From the measurement, the length L _f is specified as the first length information, the length L _l is specified as the second length information, and the length L _ap is specified as the third length information. As shown in FIG. First length information to third length information are acquired. The first length information to the third length information are input from the information input unit 15 (S51).

The rotational position of the crank 31 is detected by the first detector 11 shown in FIGS. As shown in FIG. 4, the crank 31 because it has a fixed length, the length L _c of the center position of the crank shaft 30 to the center position of the pedal shaft 32 is always the same.
For this reason, the rotational position in the two-dimensional coordinate system from the crankshaft 30 to the pedal shaft 32 is calculated by the following equations (1) and (2), where θ is the crank angle formed by the Z-axis and the crank 31. specified by coordinate positions in the axial direction X _p and Z-axis coordinate position Z _p. The rotational position is calculated by the arithmetic processing unit 14 shown in FIGS.


When the rotational position of the pedal shaft 32 is calculated by the above formulas (1) and (2), the rotational position information of the pedal shaft 32 is acquired as shown in FIG. 6 (S52).
Here, it is assumed that the angular velocity of the crank angle θ 1 is constant. The arithmetic processing unit 14 can calculate, for example, the number of pedal rotations per minute, so that the time required for one cycle can be calculated based on the calculation result, and the angular velocity can be calculated. This angular velocity is calculated by the arithmetic processing unit 14.

  The pedaling force acting on the pedal shaft 32 is detected via the pedal 33 by the second detector 12 shown in FIGS. 1 and 2. The second detection unit 12 uses a pedal force detection sensor, specifically a three-component force meter or a six-component force meter, and detects the magnitude and direction of the pedal force in the two-dimensional coordinate system. When the pedal effort is detected, the pedal effort information is acquired as shown in FIG. 6 (S53).

Here, as shown in FIG. 7, pedal force information is acquired every time the crank 31 rotates, for example, 30 degrees, and when the crank 31 rotates once, the pedal force information is acquired 12 times. As shown in FIG. 8, the pedaling force information is the magnitude of the force acting in the X-axis direction at every predetermined rotation angle of the crank 31, where the horizontal axis is the crank angle [deg] and the vertical axis is the pedaling force [N]. And information indicating the magnitude of the force acting in the Z-axis direction.
The data F _x1 and F _z1 are measured values of the force acting in the X-axis direction and the force acting in the Z-axis direction which are precisely measured at every one-hundredth rotation angle by dividing one rotation of the crank 31 into 100. It is. The data F _x2 and F _z2 are obtained by dividing the rotation of the crank 31 into 12 parts using the second detection unit 12 used in the present embodiment, and measuring the X-axis direction at every one-twelfth rotation angle. Is a measured value of the force acting on the Z axis and the force acting in the Z-axis direction.
From both data, the pedaling force measured by the second detector 12 is not significantly different from the precisely measured pedaling force, and the pedaling force information acquired by the second detector 12 is accurate. Note that the number of times the pedal force information is acquired per one rotation of the crank 31 is not limited to 12 times.

Next, the posture angle of the pedal 33 with respect to the pedal shaft 32 is detected by the third detector 13 shown in FIGS. 1 and 2, and the posture angle information of the pedal 33 is acquired as shown in FIG. 6 (S54). ).
As shown in FIG. 4, assuming that the right foot S12 (the shoe) is fixed to the pedal 33, the length L _ap from the right ankle joint J11 to the pedal shaft 32 is always constant. As shown in FIG. 5, when viewed in a two-dimensional coordinate system centered on the pedal 33, the coordinates of the joint position of the right ankle joint J11 relative to the pedal shaft 32 are represented by (a ₁ , a ₂ ).
The joint position of the right ankle joint J11 from the crankshaft 30 is the coordinate position in the X-axis direction calculated by the following expressions (3) and (4), where θ _p is the posture angle formed by the X-axis and the pedal 33. identified by X _a and Z-axis coordinate position Z _a. Coordinates X _a and coordinate position Z _a is calculated by the arithmetic processing unit 14 (S55).


When the joint position of the right ankle joint J11 is calculated based on the above formulas (3) and (4), the first joint position information is acquired (S56).

  On the other hand, the first joint position information can be acquired from the measured values measured in advance or from the information stored in the database (S57). At this time, in the joint torque calculation system 10, the third detection unit 13 that detects the posture angle of the pedal 33 may or may not be provided. The first joint position information is input from the information input unit 15.

Next, as shown in FIG. 6, the joint position of the right knee joint J10 is calculated (S58), and the second joint position information is acquired (S59). As shown in FIG. 4, the joint position of the right knee joint J10 includes the third joint position information of the right hip joint J9, the rotational position information of the pedal shaft 32, the first length information to the third length information, Based on the first joint position information of the right ankle joint J11, the calculation processing unit 14 calculates. Geometric calculation is used for this calculation. When the joint position of the right knee joint J10 is calculated, the joint position of the right knee joint J10 is acquired as the second joint position information based on the calculation result.
Here, the first joint position information of the right ankle joint J11, the second joint position information of the right knee joint J10, and the joint position information of the lower limbs of the third joint position information of the right hip joint J9 are all acquired.

  Note that the joint position of the left joint (left knee joint) J13 of the user 40 is calculated by the joint torque calculation system 10 based on the same procedure, and joint position information is acquired.

  The joint torque calculation system 10 is configured to acquire the second joint position information for each constant rotation angle of the crank 31. Here, the second joint position information is acquired every time the crank 31 rotates 30 degrees, and the second joint position information is acquired twelve times when the crank 31 rotates once, similarly to the number of times the pedal force information is acquired (see FIG. 7). Similarly, the number of acquisition times of the second joint position information per rotation of the crank 31 is not limited to 12 times.

  As shown in FIG. 6, calculation processing by inverse dynamics analysis (musculoskeletal analysis) is performed, and the joint torque of at least one of the right ankle joint J11, the right knee joint J10, and the right hip joint J9 is calculated (S60). ). The joint torque is calculated based on the pedal effort information acquired from the second detection unit 12 and at least one joint position information of the first joint position information, the second joint position information, and the third joint position information. Is calculated by

In inverse dynamics analysis, the Newton Euler method is used to calculate the joint torque.
First, the relationship between the joint reaction force and the joint torque of the right ankle joint J11 of the lower limb system of the user 40 is expressed by the following formulas (5) and (6).

Here, the meanings of the symbols used in each formula are as follows.

By combining the above equations (5) and (6), the following equation (7) representing the joint torque can be obtained for the right ankle joint J11.

  In the inverse dynamic analysis, the calculation is started from the link side of the end portion in contact with the outside of the user 40, here the right foot S12 side, and the joint torque is sequentially calculated toward the trunk of the user 40. According to the Newton Euler method, not only a numerical solution can be obtained, but also an analytical solution can be obtained as shown in the above equation (7).

  That is, the first term on the right side of the equation (7) is an equivalent torque for applying a pedal effort equivalent to the pedal 33 by the moment arm from the right foot joint J11 to the pedal shaft 32. The second term on the right side is a torque for accelerating the gravity center of the right foot S12 against the gravity. The third term on the right side is a torque for realizing a change in the angular momentum of the right foot S12.

Furthermore, the expression (8) representing the joint torque can be obtained for the right knee joint J10 by an inductive technique. Similarly, for the right hip joint J9, Expression (9) representing the joint torque can be obtained.

When the joint torques of the right ankle joint J11, the right knee joint J10, and the right hip joint J9 are calculated, as shown in FIG. 6, the joint torque of each joint of the lower limb system is acquired (S61).
When the joint torque is acquired, the joint torque can be output as a numerical value, a symbol, or a graph in the information output unit 16 shown in FIGS. The information output unit 16 can display the joint torque 12 times in real time in the same manner as the number of times the pedal force information is acquired and the number of times the second joint position information is acquired per rotation of the crank 31, for example. Further, the information output unit 16 can display the joint torque at the corresponding rotational position corresponding to each rotational position of the crank 31.

[Measuring method of joint power]
In the joint torque calculation system 10 according to the present embodiment, as shown in FIG. 6, the joint power is calculated after the joint torque is acquired (S62). As described above, the joint torque of the lower limb system during the pedaling operation of the user 40 in the bicycle 20 is calculated. Here, it is possible to realize pedaling performance indexing by acquiring a meaningful physical quantity for the user 40 from the acquired joint torque information and determining the magnitude of the physical quantity.

More specifically, as shown in FIG. 1, the user 40 transmits power to the pedal 33 of the bicycle 20. The power transmitted to the pedal 33 is transmitted to the chain 34 through the pedal shaft 32, the crank 31, the crankshaft 30, and the front gear 29 in order. This power is further transmitted to the rear wheel 28 via the rear gear 27 and becomes the driving force of the bicycle 20. With reference to FIG. 9, the source of the power transmitted to the pedal 33, that is, the pedal power (propulsion power) can be derived from the equation of motion for the user 40 as shown in the following formula (10).

Here, the meanings of the symbols used in each formula are as follows.

  The first term on the right side of the above formula (10) is the power by the translational motion of the hip joint, here the right hip joint J9. The second term on the right side is the hip joint power of the right hip joint J9, the third term on the right side is the knee joint power of the right knee joint J10, and the fourth term on the right side is the ankle joint power of the right ankle joint J11. That is, joint power is represented by the product of joint torque and angular velocity. The joint power is calculated by the arithmetic processing unit 14 shown in FIGS. 1 to 3, and when this joint power is calculated, the joint power is acquired as shown in FIG. 6 (S63).

Here, the power by translational motion of the hip joint in the first term on the right side is the component in which the user 40 pushes the foot downward through the hip joint using the weight of the upper body, the component that moves the right foot through the movement of the left foot, and the handlebar 24 is pushed strongly. Contains components that transmit force to the lower limbs by pulling back. That is, it is not a power generated purely by the hip joint, but a component other than the lower limb that affects the pedal 33 through the hip joint.
The contribution ratio of the hip joint power to the pedal power is expressed by the following equation (11).

The contribution ratio of power due to the translational movement of the hip joint is not dominant in the pedal power, and as a result of the experiment, it only dominates about 10% of the whole (see FIG. 13).

  The pedal power is a physical quantity that changes from moment to moment because it is the amount of change in energy per unit time. Accordingly, the contribution ratio of each component of the first term on the right side to the fourth term on the right side of the formula (10) with respect to the pedal power changes every moment.

Therefore, the ratio between the average value of the pedal power per predetermined rotation angle (per cycle) of the pedal 33 and the average value of each component is calculated using the following equation (12), and the joint power is quantified ( S64). In Expression (12), the ratio of the average value of the pedal power and the average value of the hip joint power is calculated, and the hip joint power is quantified. Other joint powers can be quantified by the same method. The predetermined rotation angle is an angle during one rotation of the crank 31, for example, an angle of 180 degrees from the top dead center to the bottom dead center of the crank 31, one rotation of the crank 31, or a plurality of rotations of two or more rotations. Used to mean including.

Here, t _cycle is the time required for the pedal 33 to make one rotation.

  Thereafter, the quantified joint power is compared with the threshold value, and the magnitude of the joint power is determined with respect to the threshold value (S65). For example, if it is determined that the right hip joint power is greater than the threshold, the user 40 can recognize that a large hip joint power is generated at the right hip joint J9. If it is determined that the right hip joint power is smaller than the threshold value, the user 40 can recognize that a small joint power is generated in the right hip joint J9. In addition to one side of the lower limb, for example, the difference between the joint power of the right hip joint J9 and the joint power of the joint J12 (left hip joint shown in FIG. 1) can also be determined. The determination is executed in the arithmetic processing unit 14 shown in FIGS. 1 to 3, and the determination result is displayed as a pedaling performance on the information output unit 16 by a numerical value, a symbol, or a graph.

  In addition, the pedaling performance calculates the maximum value and the minimum value of the joint power in one cycle of the pedal 33, and determines the magnitude of the maximum value of the joint power with respect to the threshold and the magnitude of the minimum value with respect to the threshold, respectively. The determination result may be determined by the user 40. In addition, the pedaling performance may be determined by the user 40 by calculating a fluctuation value in one cycle of the pedal 33, determining the magnitude of the fluctuation value of the joint power with respect to the threshold value, and determining the result.

  When these series of procedures are completed, the joint torque measurement method using the joint torque calculation system 10 is completed as shown in FIG.

[Operation and effect of the present embodiment]
As shown in FIGS. 1 and 2, the joint torque calculation system 10 according to the present embodiment includes a first detection unit 11, a second detection unit 12, and a calculation processing unit 14. The first detector 11 is connected at one end to the crankshaft 30 of the bicycle 20 and detects the rotational position of the crank 31 that rotates about the crankshaft 30. The second detection unit 12 detects a pedal force acting on a pedal 33 connected to the other end of the crank 31 via a crankshaft 32.

The arithmetic processing unit 14 includes the rotation position information acquired from the first detection unit 11, the first length information to the third length information, the first joint position information of the right ankle joint J11, and the first hip position J9. Based on the three joint position information, the second joint position information of the right knee joint J10 is calculated.
Here, as shown in FIG. 4, the rotational position information is also rotational position information of the pedal shaft 32 that rotates about the crankshaft 30 via the crank 31. The first length information is the length information from the right hip joint J9 to the right knee joint J10, the second length information is the length information from the right knee joint J10 to the right ankle joint J11, and the third length information is the right ankle joint. This is the length information from J11 to the pedal shaft 32. The length value of the first length information, the length value of the second length information, and the length value of the third length information are each constant. The third joint position information is position information of the right hip joint J9 whose position is fixed. The first joint position information is the position information of the right ankle joint J11, and varies as the posture angle of the pedal 33 changes as shown in FIG.
For example, the first joint position information is acquired as an initial value, or is acquired from an actual measurement value of the posture angle of the pedal 33.
The arithmetic processing unit 14 can easily calculate the second joint position information by geometric calculation based on the first joint position information.

When the second joint position information is calculated by geometric calculation, the first joint position information, the second joint position information, and the third joint position information are all specified. The arithmetic processing unit 14 performs an inverse dynamic analysis based on at least one of the first joint position information, the second joint position information, and the third joint position information, and the pedal effort information acquired from the second detection unit 12. Perform the calculation process by.
Thereby, the arithmetic processing unit 14 calculates the joint torque of at least one of the right ankle joint J11, the right knee joint J12, and the right hip joint J9 by simple arithmetic processing without using a large-scale device such as a motion capture system. Can be calculated. Similarly, the joint torque can be calculated for the joint J14, the joint J13, and the joint J12 on the left side of the lower limb of the user 40.

  Therefore, the joint torque calculation system 10 can be downsized with a simple configuration, and can measure the joint torques of the lower limb joints J9 to J14 in a short time.

FIG. 10A shows the measurement result of the knee joint torque using the joint torque calculation system 10 according to the present embodiment. The horizontal axis is the rotation angle [deg] of the crank 31, and the vertical axis is the knee joint torque [Nm]. The knee joint torque is measured (calculated) every 30 degrees of the rotation angle of the crank 31. That is, twelve knee joint torques are measured in one rotation of the crank 31.
FIG. 11A shows the measurement results of knee joint torque using a large-scale device including a motion capture system. Here, a precise pedal force meter is used, the knee joint torque is measured every 3.6 degrees of the rotation angle of the crank 31, and the knee joint torque is measured 100 times in one rotation of the crank 31.
The measured values of the knee joint torque and the change tendency of the knee joint torque shown in FIG. 10A are almost the same as the measured values of the knee joint torque and the change tendency of the knee joint torque shown in FIG. ing. That is, the accuracy of the measurement result of the knee joint torque using the joint torque calculation system 10 is high, and there is sufficient practicality.

FIG. 10B shows the calculation result of the hip joint torque using the joint torque calculation system 10 according to the present embodiment. The horizontal axis is the rotation angle [deg] of the crank 31, and the vertical axis is the hip joint torque [Nm]. The hip joint torque is calculated every 30 degrees of the rotation angle of the crank 31. That is, twelve hip joint torques are measured in one rotation of the crank 31.
FIG. 11B shows the calculation result of the hip joint torque using the large-scale apparatus. The hip joint torque is calculated every 3.6 degrees of the rotation angle of the crank 31, and 100 hip joint torques are calculated in one rotation of the crank 31.
The calculated value of the hip joint torque and the change tendency of the hip joint torque shown in FIG. 10B are substantially the same as the calculated value of the hip joint torque and the change tendency of the hip joint torque shown in FIG. Also here, the accuracy of the calculation result of the hip joint torque using the joint torque calculation system 10 is high, and there is sufficient practicality.

The joint torque calculation system 10 according to the present embodiment further includes an information input unit 15 and an information output unit 16 as shown in FIGS. Since at least the first length information, the second length information, and the third length information are input to the information input unit 15, the second joint position information can be calculated in the arithmetic processing unit 14 by this input.
On the other hand, the information output unit 16 outputs at least the calculation result of the joint torque calculated by the arithmetic processing unit 14. Since the information output unit 16 is equipped with a display function, the user 40 can visually check the calculation result of the joint torque.

Furthermore, in the joint torque calculation system 10 according to the present embodiment, since the first joint position information is generated based on the actual measurement of the joint position of the right ankle joint J11, additional devices such as sensors are eliminated. For example, as shown in FIGS. 4 and 5, the third length information (length L _ap ) from the right ankle joint J11 to the pedal shaft 32 is measured using a measure, and this measured value is the first joint position. Information.
In addition, as the first joint position information, for example, joint position information averaged for each skill level of the user 40 performing the pedaling operation, each physique of the user 40, and the like and made into a database can be used. And 1st joint position information is input from the information input part 15 shown by FIGS. 1-3. For this reason, the joint torque calculation system 10 can be further reduced in size because there is no additional device.

Further, the joint torque calculation system 10 according to the present embodiment further includes a third detection unit 13 as shown in FIGS. 1 and 2. The third detector 13 detects the posture angle of the pedal 33 on the pedal shaft 32. When the posture angle information of the pedal 33 is acquired, as shown in FIGS. 4 and 5, the posture angle information and the third length information (length L _ap ) from the right ankle joint J11 to the pedal shaft 32 are obtained. Based on the above, the arithmetic processing unit 14 can calculate the first joint position information.
For this reason, since the first joint position information can be calculated in real time based on the attitude angle information acquired from the third detection unit 13, the joint torque can also be calculated in real time. For example, 12 joint torques per rotation of the crank 31 can be calculated in real time.
Moreover, since the 3rd detection part 13 is a very small apparatus (parts), such as an inertial sensor, size reduction of the joint torque calculation system 10 is realizable. For example, since a commercially available inertial sensor can be used as the third detection unit 13, the manufacturing cost of the joint torque calculation system 10 can also be reduced.

Further, in the joint torque calculation system 10 according to the present embodiment, the calculation processing unit 14 calculates a physical quantity (see FIG. 9) and determines the magnitude of the physical quantity with respect to the threshold value. The physical quantity is calculated as a physical quantity in the joint per predetermined rotation angle of the crank 31 based on the joint torque and the rotational position information. The threshold is arbitrarily set.
For this reason, as a result of determining the magnitude of the physical quantity, for example, the pedaling skill of the user 40 can be measured. In addition, based on the measurement results of pedaling skills, the operation state of the bicycle such as positioning and pedaling can be confirmed by the user 40 itself, and a third party can propose an ideal operation state to the user 40. Become.

  Further, in the joint torque calculation system 10 according to the present embodiment, as shown in FIG. 9, since the physical quantity is the joint power derived based on the joint torque and the angular velocity of the joint, the pedaling performance of the user 40 Can be quantified.

FIG. 12A shows the calculation result of the hip joint torque using the joint torque calculation system 10 according to the present embodiment. The horizontal axis is the rotation angle [deg] of the crank 31, and the vertical axis is the hip joint torque [Nm / W]. Data to which reference numeral 40 (1) is attached is a calculation result of hip joint torque of a user 40 who is an advanced user (the same applies to FIGS. 12A to 12C). The data to which reference numeral 40 (2) is attached is the calculation result of the hip joint torque of the intermediate user 40 (the same applies to FIGS. 12A to 12C).
The hip joint torque of the advanced person is approximately twice as large as the hip joint torque of the intermediate person when the crank angle is around 90 degrees.

  FIG. 12B shows the calculation result of the angular velocity of the hip joint. The horizontal axis represents the rotation angle [deg] of the crank 31, and the vertical axis represents the angular velocity [deg / sec] of the hip joint. Since the angular velocity is determined geometrically, there is little difference in angular velocity regardless of the skills of advanced and intermediate players.

FIG. 12C shows a calculation result of the hip joint power. The horizontal axis is the rotation angle [deg] of the crank 31, and the vertical axis is the hip joint power.
In the advanced player, the peak of the hip joint torque is matched with the peak of the angular velocity of the hip joint having a crank angle of around 90 degrees, so the hip joint power is extremely large. The hip joint power of advanced players is about twice as high as that of intermediate players.

FIG. 13 is a graph showing the calculation results of the ratio of each joint power of the lower limbs. The horizontal axis indicates the power by rotation including the ankle joint power, the knee joint power, and the hip joint power and the power by the translational motion of the hip joint from the left side to the right side. The vertical axis represents the ratio [%] of each joint power. Data with reference numerals 40 (11) and 40 (12) are the calculation results of the joint powers of the two advanced players. Data with reference numerals 40 (21), 40 (22), and 40 (23) are the calculation results of the joint powers of the three intermediate players. The data with reference numerals 40 (31), 40 (32), and 40 (33) are the calculation results of the joint powers of the three beginners.
In advanced players, the knee joint power ratio is lower than in intermediate and beginners, so the burden on knee joints is low. Moreover, since the ratio of the hip joint power is higher in the advanced person than in the intermediate and beginners, the burden ratio of the hip joint is high.

Furthermore, in the joint torque calculation system 10 according to the present embodiment, the joint power calculated by the calculation processing unit 14 is output from the information output unit 16 shown in FIGS. In the arithmetic processing unit 14, for example, as illustrated in FIG. 12C, the hip joint power is calculated as one physical quantity, and the calculation result is displayed from the information output unit 16 as a numerical value, a symbol, a graph, or the like. Further, in the arithmetic processing unit 14, for example, as shown in FIG. 13, the ratio of each joint power is calculated as a physical quantity, and the calculation result is displayed from the information output unit 16 as a graph.
For this reason, the pedaling performances of the advanced, intermediate, and beginner can be clearly and clearly recognized by the visual observation of the user 40.

  In the joint torque calculation system 10 according to the present embodiment, the joint torque is calculated in real time by the calculation processing unit 14 and output in real time by the information output unit 16. For example, 12 joint torques can be displayed every 30 degrees of the rotation angle of the crank 31. For this reason, for example, the user 40 can confirm the joint torque visually in real time.

  Furthermore, in the joint torque calculation system 10 according to the present embodiment, the joint torque and the joint power are calculated in real time by the calculation processing unit 14, and at least the joint power is output in real time by the information output unit 16. For this reason, for example, the user can confirm at least the joint power by visual observation in real time.

  As shown in FIG. 3, in the cycle computer 19 according to the present embodiment, the arithmetic processing unit 14 is built in the housing 190. Since the cycle computer 19 is mounted compactly on the bicycle 20, for example, the joint torque and joint power are calculated while the bicycle 20 is running, and the user 40 can visually confirm the pedaling performance.

  In the cycle computer 19, the joint torque calculation result (joint torque information), joint power is stored in a storage device (not shown) built in the arithmetic processing unit 14 or a storage device external to the arithmetic processing unit 14. The calculation result (joint power information) can be stored. These pieces of information can be transferred to an external computer (for example, a notebook personal computer or a portable terminal) via the interface of the cycle computer 19. Thereby, the pedaling performance can be analyzed using the external computer while the bicycle 20 is traveling or after traveling.

  Further, as shown in FIG. 6, in the joint torque measuring method according to the present embodiment, first, the rotational position of the crank 31 that rotates around the crankshaft 30 of the bicycle 20 shown in FIGS. 1 and 4 is detected. Then, rotational position information is acquired (S52). On the other hand, the pedal effort acting on the pedal shaft 32 connected to the crankshaft 30 via the crank 31 is detected, and the pedal effort information is acquired (S53). Further, the first length information to the third length information are acquired (S51), and the first joint position information of the right ankle joint J11 is acquired (S56 or S57). In addition, each acquisition order of rotation position information, 1st length information-3rd length information, and 1st joint position information is not ask | required.

Here, the rotational position information is also rotational position information of the pedal shaft 32 that rotates about the crankshaft 30 via the crank 31. For example, on the right side of the lower limb, the first length information is the length information from the right hip joint J9 to the right knee joint J10, the second length information is the length information from the right knee joint J10 to the right ankle joint J11, and the third length. The length information is length information from the ankle joint J11 to the pedal shaft 32. The value of the length L _f of the first length information, the value of the length L _l of the second length information, and the value of the length L _ap of the third length information are constant. The third joint position information is position information of the right hip joint J9 whose position is fixed. The first joint position information is the position information of the right ankle joint J11 and fluctuates as the posture angle of the pedal 33 changes. Based on the first joint position information, the second joint position information (position information of the right knee joint J10) can be easily calculated by geometric calculation.

When the second joint position information is calculated by geometric calculation, the first joint position information, the second joint position information, and the third joint position information are all specified. Based on at least one information of the first joint position information, the second joint position information, and the third joint position information, and the pedaling force information acquired from the second detection unit 12 shown in FIGS. 1 and 2, the reverse power Arithmetic processing by academic analysis is performed.
Accordingly, at least one joint torque of the right ankle joint J11, the right knee joint J10, and the right hip joint J9 can be calculated by a simple calculation process without using a large-scale device such as a motion capture system.
Therefore, in the joint torque measurement method, the size can be reduced with a simple configuration, and the joint torque of the lower limb joint can be measured in a short time.

In the joint torque measurement method according to the present embodiment, the physical quantity is calculated, and the magnitude of the physical quantity with respect to the threshold is determined. The physical quantity is calculated as a physical quantity in the joints J9 to J14 per predetermined rotation angle of the crank 31 based on the joint torque and the rotational position information. The threshold is arbitrarily set.
For this reason, as a result of determining the magnitude of the physical quantity, for example, the pedaling performance (pedaling skill) of the user 40 can be measured. Further, based on the measurement result of pedaling performance, it is possible for the user 40 to propose optimal positioning, optimal pedaling, and the like.

[Other Embodiments]
Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention.
For example, in the above-described embodiment, the present invention is applied to the measurement (calculation) of the joint torque and joint power of the user's lower limb riding on a bicycle. You may apply to the measurement of torque or joint power.
In the above embodiment, the user is a human, but the present invention is applied to, for example, a humanoid robot having links and joints equivalent to those of humans, and a robot having links and joints equivalent to lower limbs. can do. Of course, the present invention can also be applied to measurement of animal joint torque and joint power.
Furthermore, in the above-described embodiment, an example in which the information output unit is applied to a display device has been described. However, the information output unit may be an audio output device, or a display device and an audio output device may be mixed. . Specifically, the voice output device is configured to notify the user who is operating the bicycle of joint torque and joint power by voice.

  DESCRIPTION OF SYMBOLS 10 ... Joint torque calculation system, 11 ... 1st detection part, 12 ... 2nd detection part, 13 ... 3rd detection part, 14 ... Calculation processing part, 15 ... Information input part, 16 ... Information output part, 19 ... Cycle computer , 20 ... bicycle, 30 ... crankshaft, 31 ... crank, 32 ... pedal shaft, 33 ... pedal, 40 ... user, S1-S15 ... link (segment). J1 to J14: Joints.

Claims (11)

A first detector that is connected to a crankshaft of a bicycle and that detects a rotational position of a crank that rotates about the crankshaft;
A second detector for detecting a pedal force acting on a pedal connected to the other end of the crank via a pedal shaft;
The rotational position information acquired from the first detection unit, the first length information from the hip joint to the knee joint, the second length information from the knee joint to the ankle joint, and the first length information from the ankle joint to the pedal shaft. Based on the three length information, the first joint position information of the ankle joint, and the third joint position information of the hip joint, the second joint position information of the knee joint is calculated and acquired from the second detection unit Based on the pedaling force information and at least one of the first joint position information, the second joint position information, and the third joint position information, performing an arithmetic process by inverse dynamics analysis, An arithmetic processing unit for calculating a joint torque of at least one of the knee joint and the hip joint;
Joint torque calculation system with An information input unit for inputting at least the first length information, the second length information, and the third length information;
An information output unit for outputting at least the calculation result of the joint torque;
The joint torque calculation system according to claim 1, further comprising: A third detector for detecting a posture angle of the pedal on the pedal shaft;
The joint torque calculation system according to claim 2, wherein at least one of the first joint position information and the pedal effort information is generated using angle information acquired from the third detection unit. The arithmetic processing unit includes:
Based on the joint torque and the rotational position information, a physical quantity per predetermined rotation angle of the crankshaft is calculated in the joint;
The joint torque calculation system according to claim 2 or 3, wherein the magnitude of the physical quantity with respect to a threshold is determined. The joint torque calculation system according to claim 4, wherein the physical quantity is joint power derived based on the joint torque and an angular velocity of the joint. The joint torque calculation system according to claim 5, wherein the information output unit outputs the joint power. The rotational position information is acquired from the first detection unit in real time,
The pedal effort information is acquired in real time from the second detection unit,
The arithmetic processing unit calculates the joint torque in real time,
The joint torque calculation system according to claim 2, wherein the information output unit outputs the joint torque in real time. The rotational position information is acquired from the first detection unit in real time,
The pedal effort information is acquired in real time from the second detection unit,
The arithmetic processing unit calculates the joint torque and the joint power in real time,
The joint torque calculation system according to claim 6, wherein the information output unit outputs at least the joint power in real time.   A cycle computer in which the arithmetic processing unit according to any one of claims 1 to 8 is built in a housing. One end of the bicycle is connected to the crankshaft, and the rotational position of the crank that rotates around the crankshaft is detected to obtain rotational position information.
Detecting pedaling force information acting on a pedal connected to the other end of the crank via a pedal shaft to obtain pedaling force information;
Obtaining first length information from the hip joint to the knee joint, second length information from the knee joint to the ankle joint, and third length information from the ankle joint to the pedal shaft;
Obtaining first joint position information of the ankle joint and third joint position information of the hip joint;
Based on the rotational position information, the first joint position information, and the third joint position information, the second joint position information of the knee joint is calculated,
Based on the pedaling force information and at least one information of the first joint position information, the second joint position information, and the third joint position information, a calculation process by inverse dynamics analysis is performed, and the ankle joint, A joint torque measuring method for calculating a joint torque of at least one of the knee joint and the hip joint. Based on the joint torque and the rotational position information, a physical quantity per predetermined rotation angle of the crankshaft is calculated in the joint;
The method for measuring joint torque according to claim 10, wherein the magnitude of the physical quantity with respect to a threshold is determined.