Systems, methods and apparatus for calibrating differential air pressure devices

Abstract

Methods, apparatus, and systems for calibrating differential air pressure systems are described. The methods, apparatus, and systems may be adapted for physical training of an individual, e.g. as a training tool to improve performance or as a physical therapy tool for rehabilitation or strengthening. The differential air pressure systems comprise a chamber for receiving at least a portion of a user's body. In one embodiment, a method for calibrating a differential air pressure system for predicting effective body weight of a user versus system pressure is described. In certain variations, the methods, apparatus and systems may comprise adjusting pressure in the system until one or more force values are reached. The methods described herein may comprise determining a relationship between body weight force and pressure, allowing the user to set a pressure or a parameter correlated with pressure to achieve a desired effective body weight.

1 . A method for applying pressure to a portion of an individual's body comprising:
 receiving a portion of the individual's body in an pressurizable chamber;   producing a pressure inside the chamber;   increasing the chamber pressure to a predetermined threshold system pressure;   sensing the individual's weight in the chamber at at least two pressures different from the threshold system pressure; and   generating a pressure and weight relationship for the individual based at least in part on the individual's sensed weight in the chamber at the at least two pressures.   
     
     
         2 . The method of  claim 1 , further comprising regulating the pressure in the chamber according to the pressure and weight relationship for the individual. 
     
     
         3 . The method of  claim 1 , wherein during the increasing step a flexible portion of the pressurizable chamber expands in response to the increasing chamber pressure. 
     
     
         4 . The method of  claim 1 , further comprising: inflating a soft shell portion of the pressurizable chamber at least partially surrounding the portion of the individual's body in response to increasing the chamber pressure to the predetermined threshold system pressure. 
     
     
         5 . The method of  claim 1 , further comprising offloading the individual's weight in the chamber by increasing the chamber pressure above the predetermined threshold system pressure. 
     
     
         6 . The method of  claim 1 , the generating step further comprising: adjusting the generated relationship with test data of various subjects. 
     
     
         7 . A system for applying pressure to a portion of an individual's body comprising:
 a pressurizable chamber configured to receive a portion of an individual's body and to apply pressure to the portion during exercise;   a weight sensor connected to the apparatus for measuring the weight of the individual within the pressurizable chamber and electronically communicating the measured weight to a processor;   a pressure sensor connected to the pressurizable chamber for measuring the pressure within the pressurizable chamber and electronically communicating the measured pressure to the processor, the processor configured to pressurize the chamber to a predetermined threshold system pressure, receive output from the weight sensor at at least two pressure values different from the threshold system pressure, and generate a measured weight and pressure relationship for the individual.   
     
     
         8 . The system of  claim 7 , wherein the processor is further configured to regulate the system pressure according to the measured weight and pressure relationship for the individual. 
     
     
         9 . The system of  claim 7 , wherein the processor is further configured to unweight the individual in the chamber according to the measured weight and pressure relationship for the individual. 
     
     
         10 . The system of  claim 7 , wherein the processor is further configured to adjust the measured weight and pressure relationship with test data for various subjects. 
     
     
         11 . The system of  claim 7 , wherein the weight sensor is further configured to continuously measure the individual's weight while pressure increases in the chamber. 
     
     
         12 . The system of  claim 7 , wherein the weight sensor is further configured to continuously measure the individual's weight during exercise in the chamber. 
     
     
         13 . A method for calibrating a differential pressure system comprising:
 receiving a portion of the individual's body in an expandable pressurizable chamber;   producing a pressure inside a chamber;   sensing the individual's weight in the chamber at at least two different pressures; and   generating a pressure and weight relationship for the individual from the sensed weight at the two pressures; and   refining the pressure and weight relationship for the individual.   
     
     
         14 . The method of  claim 13 , wherein refining the pressure and weight relationship comprises measuring the weight experienced by the user at additional pressure points and adjusting the relationship based on the additional measured weight at the additional pressure points. 
     
     
         15 . The method of  claim 13 , wherein refining the pressure and weight relationship further comprising increasing the range of pressures over which weight is measured. 
     
     
         16 . The method of  claim 13 , further comprising generating a pressure and operation parameter relationship for pressure in the system and an operation parameter of a device connected to the differential pressure system. 
     
     
         17 . The method of  claim 16 , wherein the operation parameter is an incline of a treadmill in the chamber. 
     
     
         18 . The method of  claim 13 , further comprising scaling the generated pressure and weight relationship with test data from various subjects. 
     
     
         19 . The method of  claim 13 , further comprising repeating the performance of one or more of the steps of calibrating the differential pressure system pressure system while the individual is operating an exercise device in the chamber. 
     
     
         20 . The method of  claim 13 , wherein the refining step comprises sensing and recording weight experienced by the individual at more than two pressure points.