Method and Apparatus for Analysis of Gait and to Provide Haptic and Visual Corrective Feedback

Abstract

A system for analysis of user gait and to provide correction in form of haptic and visual feedback. This system comprises a motion and force sensors and a haptic actuator embedded in the user shoe insoles in communication with a smart-phone based analysis application, configured to calculate motion and orientation of the user feet in relation to the value, location and distribution of ground reaction forces measured by sensors located in the shoe insoles and after analysis of said forces and motion, to provide haptic feedback to the user foot instructing about the location (and timing) of pressure the user must apply to achieve an optimal gait.

We claim: 
     
         1 . A system to analyze and correct gait and balance of a selected user by estimating vertical ground reaction force vector applied to the selected user feet and limbs and to provide haptic corrective feedback comprising:
 a motion processing element;   a force processing element; and   a haptic processing element   and wherein said motion, force and haptic processing elements are embedded in the selected user shoe insoles, and are in communication with gait analysis application based in the selected user smart-phone using wireless radio interface, and wherein the motion processing element is configured to estimate timing and phase of gait cycle by analyzing feet motion and to send said estimate as a first information to the gait analysis application, and wherein the force processing element comprising one or more force sensors is configured to estimate value, and location of ground reaction force transferred to the insoles and send said estimate as a second information to the gait analysis application, and wherein based on the first information and the second information the gait analysis application estimates location of the Center of Pressure (COP) applied to the selected user feet, then combining said estimates with the third information containing the selected user physical characteristics, and the forth information containing the selected user calibration parameters, estimates location and movement of the selected user Center of Mass (COM), and wherein after obtaining said estimation in conjunction with the estimation of selected user velocity obtained from the Global Position System (GPS) provides analysis of the selected user gait and the haptic corrective feedback.   
     
     
         2 . The system of  claim 1 , wherein motion processing elements comprises of:
 a three-axis accelerometer;   a three-axis gyroscope;   a three-axis magnetometer;   and wherein the force processing element comprises of:   a multiplicity of force pressure sensors;   and wherein the haptic corrective feedback element comprises a haptic actuator, and wherein said motion, force elements are configured to measure motion of a selected user feet in a three-dimensional (3-D) space and in relation to reaction force vector transferred from a ground to a selected user feet and limbs, and to communicate said motion and forces to gait analysis application, and wherein the haptic corrective feedback processing element is configured to receive a control signals from the gait analysis application, convert said control signals to vibration and to provide said vibration as a stimulus to user feet.   
     
     
         3 . The system of  claim 1 , wherein third information stored in gait analysis application contains physical characteristics comprises selected user: weight and height; distance between tip of grater trochanter (hip) and the center of rotation of knee; and the distance between the center of rotation of knee and the ankle. 
     
     
         4 . The system of  claim 1 , wherein forth information stored in gait analysis application is obtained during static calibration procedures and comprises values of natural orientation of selected user position in 3-dimensional space and location, and distribution of vertical ground reaction force vectors. 
     
     
         5 . The system of  claim 1 , wherein gait analysis application is configured to retrieve motion and force data from selected user shoe insoles and combine said motion and force data with third information containing selected user physical characteristics; process said data to estimate current phase of gait, location of COP and COM, and based on said current measurements and the filtered history of past gait phases, estimate movement of COP and COM for the subsequent gait cycle, then communicate correct timing and location of the pressure point required to achieve optimal balance for the next gait cycle by applying control signal to a haptic actuator embedded in the selected user shoe insoles. 
     
     
         6 . The system of  claim 4 , wherein calibration procedures comprises:
 obtaining three-dimensional orientation of insoles placed in shoes of a selected user while the shoes, without the selected user are placed in a reference position;   obtaining recording of the insoles force sensors values without the selected user;   obtaining recording of three-dimensional orientation of insoles and the insoles force sensors values while the user stands in the shoes in a natural standing position;   and subtracting the insoles three-dimensional value obtained when insoles and shoes are placed in a reference position without the user from the values obtained while the selected stands in the shoes in a natural standing position and store said values as the user calibrated natural position; and subtract the insoles force sensors values obtained when insoles and shoes are placed in a reference position without the user from the values obtained while the selected stands in the shoes in a natural standing position and store said values as the user calibrated force values.   
     
     
         7 . The system of  claim 5 , wherein COP is obtained by performing weighted average of all pressure points over the surface of a foot then weighting said averages over both feet. 
     
     
         8 . The system of  claim 5 , wherein the COM is obtained by performing weighted average of each body segment of selected user in a 3-dimensional space obtained from motion processing element and the third information stored in gait analysis application. 
     
     
         9 . The system of  claim 1 , wherein three-dimensional motion and ground reaction force recorded during motion of a selected user and the GPS coordinates are processed locally by the selected user gait analysis application to provide visual and numerical representation of each phase of gait. 
     
     
         10 . The system of  claim 1 , wherein three-dimensional motion and ground reaction force recorded during the motion of a selected user and the GPS coordinates are transmitted to a remote server for storage or analysis by external recipients or to provide visual and numerical representation of gait. 
     
     
         11 . A method providing haptic and visual feedback intended to improve selected user balance during all phases of gait by analyzing the selected user motion in a three-dimensional space in relation to location, distribution and value of ground reaction forces transmitted to the selected user feet comprising:
 obtaining global and local coordinate system;   obtaining natural gait stance parameters;   obtaining a three-dimensional vectors of feet motion;   obtaining distribution, location and value of ground reaction force;   processing the distribution and location of ground reaction force in relation to motion vectors;   subtracting the natural gait stance parameters from the results 3-dimensional motion vectors and from the location and distribution of ground reaction force obtained during each phase of gait and use said difference to calculate the proper location of Center of Pressure (COP) for the next gait phase and communicate said location to the selected user feet;   obtaining location GPS coordinates;   processing three-dimensional motion vectors to obtain gait timing and phase;   processing of ground reaction forces in relation to gait timing and phase to obtain rotational moment applied to joints;   transmit result of gait analysis and the location GPS coordinates to a remote server using smart-phone cellular radio interface;   providing visual and numerical results of gait characteristics,   and wherein the global and local system coordinates, and three dimensional motion vectors are obtained by analyzing data from: a three-axis magnetometer sensor; a 3-axis accelerometer sensor; and a 3-axis gyroscope sensor, a 3-axis magnetometer sensor, and wherein the value, location and distribution of forces ground reaction force is obtained from multiplicity of force sensors embedded in the insoles, and wherein the timing is derived from the gait analyzer sampling interval, and wherein the instructions of location and distribution COP intended to modify gait phases or balance.   
     
     
         12 . The method of  claim 11 , wherein numerical and visual results of gait and value, location and distribution of ground reaction force transmitted to the feet and joints comprises:
 an identification of the gait cycle phase;   a motion and rotational vectors applied to joints;   an effective gait rate;   an actual location of the COP;   a desired location of the COP;   an actual location of the COM;   a desired location of the COM; and   a difference in symmetry between left and right foot,   
     
     
         13 . The method of  claim 11 , wherein instructions of correct location and distribution of COP intended to modify gait or balance is obtained by analyzing gait phase, it's timing in relation to velocity and ground reaction forces and selected user physical parameters. 
     
     
         14 . The method of  claim 13 , wherein instructions related to change in location of force intended to modify gait is provided in form of haptic vibrations to a toes of selected user feet. 
     
     
         15 . The method of  claim 14 , wherein instructions are provided in a form of varying frequencies and/or vibration amplitudes. 
     
     
         16 . The method of  claim 12 , wherein calibration procedure comprises:
 obtaining global and local coordinates from motion processing element;   obtaining selected user weight;   obtaining orientation of feet in natural stand position;   obtaining location of COP in natural standing position;   obtaining location of COM in natural standing position; and   performing measurements of distribution and location of force applied by feet of a selected user to skiboot insoles in standing position when the selected user is not in motion and the selected user rests in a natural position with body mass equally distributed between both feet;   leans on an inner edges of skis as in left and right turn; and   
       performing measurements of the distribution and the location of force applied to the skiboot insoles during a test run and storing results as a reference parameters. 
     
     
         17 . A non-transitory computer accessible memory medium for storing program instructions pertaining to a system providing haptic and visual feedback of motion and forces transmitted by feet of a selected user to a skiboot insoles, wherein the program instructions execute all of the following:
 maintaining communication with a motion and force processing elements embedded in the skiboot insoles and with a remote server;   obtaining system's global and local coordinates by analyzing data obtained from an accelerometer and magnetometer sensors;   obtaining 3D motion of feet of the selected user by analyzing data obtained from an accelerometer sensor, gyroscope sensor, magnetometer sensor and an atmospheric pressure sensor;   obtaining distribution and location of force applied by feet of the selected user to the skiboot insoles and processing said distribution and location of forces in relation to a 3D motion vectors of the skiboot insoles to derive timing of change in distribution and location of force required to perform successful turn;   providing instructions about timing of change in distribution and location of force required for successful termination of turn by applying control signals to a haptic actuators embedded in the skiboot insoles;   obtaining location GPS coordinates;   transmitting motion, forces and location GPS coordinate data to remote server using smart-phone cellular radio interface;   receiving instruction required for successful termination of turn from a remote terminal and applying said instructions as control signals to the haptic actuators embedded in the skiboot insoles;   performing calibration procedure to obtain reference values of force during static and dynamic test conditions; and   
       providing visual and numerical results of motion and timing of change in the distribution and location of force applied by feet of the selected user to the skiboot insoles. 
     
     
         18 . The non-transitory computer accessible memory medium of claim  19 , wherein results obtained during calibration, dynamic test or a regular runs are collected independently for a left turn and a right turn and sorted into a velocity and a radius bins, then said velocity and radius bins are compared and difference is displayed as difference in symmetry of force distribution.