Method and apparatus for measuring expended energy

Abstract

Measuring expended energy of a moving body by providing at least one first sensor for measuring position data of a first part of the moving body, providing at least one second sensor for measuring relative position data of a second part of the moving body, using the first sensor to make a first measurement of the position of the first part over a period of time and subsequently calculating a global expended energy of the first part relative to a reference frame from the first measurement, using the second sensor to make a second measurement of the position of the second part over said period of time and subsequently calculating a relative expended energy of the second part relative to the first part from the first and second measurements.

1 . A method of measuring expended energy of a moving body, comprising the steps:
 i) providing at least one first sensor for measuring position data and/or orientation data and/or dynamic data of a first part of the moving body;   ii) providing at least one second sensor for measuring relative position data and/or orientation data and/or dynamic data of a second part of the moving body, wherein the second part is moveable relative to the first part and connected to the first part by a first resistive deformable element;   iii) using the at least one first sensor to make a first measurement of the position and/or orientation and/or dynamics of the first part over a period of time and subsequently calculating a global expended energy of the first part relative to a reference frame from the first measurement;   iv) using the at least one second sensor to make a second measurement of the position and/or orientation and/or dynamics of the second part over said period of time and subsequently calculating a relative expended energy of the second part relative to the first part from the first and second measurements, wherein the calculation includes the energy required to deform the first resistive deformable element when moving the second part relative to the first part; and   v) calculating the total expended energy of the moving body by summing the global expended energy with the relative expended energy;
 wherein the at least one first sensor comprises a global positioning system (GPS) sensor and/or an inertial measurement unit and/or a first plurality of reference indicia measurable by an image capture device; and 
   the at least one second sensor comprises an inertial measurement unit and/or a second plurality of reference indicia measurable by an image capture device.   
     
     
         2 . A method according to  claim 1 , further comprising the steps:
 vi) providing at least one nth sensor for measuring relative position data and/or orientation data and/or dynamic data of an nth part of the moving body, wherein the nth part is moveable relative to an ith part, where n>2 and i<n;   vii) using the at least one nth sensor to make an nth measurement of the position and/or orientation and/or dynamics of the nth part over said period of time and subsequently calculating a relative expended energy of the nth part relative to the ith part from the ith and nth measurements; and   wherein the step of calculating the total expended energy of the moving body comprises summing the global expended energy with all calculated relative expended energies for each nth and ith part.   
     
     
         3 . A method according to  claim 2 , wherein the nth part is connected to an ith part by an nth resistive deformable element. 
     
     
         4 . A method according to  claim 2 , wherein each at least one second sensor, and any nth sensor present, is arranged to produce a three-dimensional rotation matrix for each of the second and any nth part. 
     
     
         5 . A method according to  claim 4 , wherein each three-dimensional rotation matrix is updated by the respective sensor periodically. 
     
     
         6 . A method according to  claim 5 , wherein each three-dimensional rotation matrix is updated by the respective sensor 100 times per second. 
     
     
         7 . A method according to  claim 1 , wherein the at least one first sensor is positioned close to the centre of mass of the moving body. 
     
     
         8 . A method according to  claim 1 , wherein the moving body is a human body. 
     
     
         9 . A method according to  claim 8 , wherein step (i) comprises disposing the at least one first sensor on or adjacent a first part of the moving body for measuring position data and/or orientation data and/or dynamic data thereof, and step (ii) comprises disposing the at least one second sensor in a handgrip device held by the hand of the moving body for measuring relative position data and/or orientation data and/or dynamic data thereof, wherein the handgrip device is moveable relative to the first part and connected thereto by the first resistive deformable element. 
     
     
         10 . A method according to  claim 9 , wherein the at least one first sensor is attached to a band that is wearable by a user, and the handgrip device is connected to the band by the first resistive deformable element. 
     
     
         11 . A method according to  claim 10 , wherein the step of calculating relative expended energy of the second part relative to the first part and/or any nth part relative to any ith part, if present, includes using inertial characteristic data associated with the second and any ith part, where the inertial characteristic data includes the relative masses of the body parts and/or the mass moments of inertia of each body part. 
     
     
         12 . A method according to  claim 11 , wherein the inertial characteristic data is obtained, at least partly, from a data table. 
     
     
         13 . A method according to  claim 11 , further comprising the step of running a forward dynamics simulation of the moving body to produce a second calculation of total expended energy, and iteratively improving the simulation using the first calculation of expended energy. 
     
     
         14 . A method according to  claim 2 , wherein the calculated global or relative energy is derived from the integral of a power-time measurement obtained from said first, second and any nth measurement. 
     
     
         15 . A method according to  claim 1 , wherein the first resistive deformable element and any nth resistive deformable element is an elasticated band. 
     
     
         16 . An apparatus for measuring expended energy of a moving body, comprising:
 at least one first sensor for measuring position data and/or orientation data and/or dynamic data of a first part of the moving body;   at least one second sensor for measuring relative position data and/or orientation data and/or dynamic data of a second part of the moving body, wherein the second part is moveable relative to the first part;   a first resistive deformable element for connecting the second part to the first part, wherein the first resistive deformable element is arranged to deform and act to resist deformation when the second part is moved relative to the first part; and   a control unit communicably coupled to the at least one first and second sensors to receive measurement data therefrom;   wherein the at least one first sensor is arranged to make a first measurement of the position and/or orientation and/or dynamics of the first part over a period of time and transmit the first measurement data to the control unit;   the at least one second sensor is arranged to make a second measurement of the position and/or orientation and/or dynamics of the second part over said period of time and transmit the second measurement data to the control unit; and   the control unit is arranged to calculate a global expended energy of the first part relative to a reference frame from the first measurement, calculate a relative expended energy of the second part relative to the first part from the first and second measurements, wherein the calculation of relative expended energy includes the energy required to deform the first resistive deformable element when moving the second part relative to the first part, and calculate the total expended energy of the moving body by summing the global expended energy with the relative expended energy;   wherein the at least one first sensor comprises a global positioning system (GPS) sensor and/or an inertial measurement unit and/or a first plurality of reference indicia measurable by an image capture device; and   the at least one second sensor comprises an inertial measurement unit and/or a second plurality of reference indicia measurable by an image capture device.   
     
     
         17 . An apparatus according to  claim 16 , further comprising an nth resistive deformable element for connecting the nth part to an ith part, wherein the nth resistive deformable element is arranged to deform and act to resist deformation when the nth part is moved relative to the ith part. 
     
     
         18 . An apparatus according to  claim 16 , further comprising at least one nth sensor communicably coupled to the control unit for measuring relative position data and/or orientation data and/or dynamic data of an nth part of the moving body, wherein the nth part is moveable relative to an ith part, where n>2 and i<n;
 wherein the at least one nth sensor is arranged to make an nth measurement of the position and/or orientation and/or dynamics of the nth part over said period of time and transmit the nth measurement to the control unit subsequently calculating a relative expended energy of the nth part relative to the ith part from the ith and nth measurements; and   wherein the step of calculating the total expended energy of the moving body comprises summing the global expended energy with all calculated relative expended energies for each nth and ith part.   
     
     
         19 . An apparatus according to  claim 16 , wherein the sensors are arranged on, or form part of, an item of clothing, and the moving body comprises the wearer of the item of clothing. 
     
     
         20 . An apparatus according to  claim 19 , wherein the sensors are arranged on the item of clothing such that, when worn, the at least one first sensor is arranged to measure position data and/or orientation data and/or dynamic data of the Lumber vertebrae of the wearer, and the at least one second sensor is arranged to measure position data and/or orientation data and/or dynamic data of the Thoracic vertebrae of the wearer. 
     
     
         21 . An apparatus according to  claim 16 , wherein each sensor is connected to at least one other sensor by a cable, wherein the cable is arranged to carry electrical power to the sensors and/or allow the transfer of data between the sensors. 
     
     
         22 . An apparatus according to  claim 16 , further comprising a transmitter communicably coupled to the sensors, wherein measurement data is transmittable to the control unit via the transmitter. 
     
     
         23 . An apparatus according to  claim 16 , wherein the at least one second sensor is on a handgrip device to be held in the hand of a user for measuring relative position data and/or orientation data and/or dynamic data of the hand. 
     
     
         24 . An apparatus according to  claim 23 , wherein the at least one first sensor is attached to a band that is wearable by a user, and the handgrip device is connected to the band by the first resistive deformable element. 
     
     
         25 . An exercise system comprising:
 an apparatus according to  claim 16 ;   a computer system loaded with a game and in communication with the apparatus; and   a display unit communicably coupled to the computer system for displaying the game;   wherein the measurements made by the sensors are used by the computer to control the game, and the calculated total expended energy of the moving body is used as part of the game.   
     
     
         26 . An exercise system according to  claim 25 , wherein the game comprises several stages that are completed upon the total expended energy exceeding a predetermined threshold.