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 of calibrating of a differential air pressure system for predicting effective body weight of a user versus system pressure, the method comprising:
 adjusting pressure inside a chamber that surrounds a portion of a user's body until body weight force on the user's body reaches a target force value;   measuring the chamber pressure at the target force value to generate a first (pressure, force) data point; and   using the first (pressure, force) data point with at least one other (pressure, force) data point to determine a relationship between body weight force experienced by the user and pressure in the chamber.   
     
     
         2 . The method of  claim 1 , wherein the target force value is a preset force value. 
     
     
         3 . The method of  claim 1 , wherein one of the at least one other (pressure, force) data point used in determining the relationship is a body weight of the user measured at ambient pressure. 
     
     
         4 . An apparatus to predict effective body weight of a user as a function of system pressure, the apparatus comprising:
 a differential air pressure system comprising a chamber configured to receive and surround at least a portion of a user's body; and   processing logic coupled with the differential air pressure system,   wherein the processing logic is configured to adjust pressure in the chamber until body weight force on the user reaches a target force value, measure the chamber pressure at the target force value to determine a first (pressure, force) data point, and to determine body weight force experienced by the user as a function of pressure in the chamber using the first (pressure, force) data point.   
     
     
         5 . A method of calibrating a differential air pressure system, the method comprising:
 adjusting pressure in a chamber of a differential air pressure system, the chamber surrounding at least a portion of a user's body;   receiving a pain indication supplied by the user as a function of pressure; and   constructing a pressure versus pain relationship for the user.   
     
     
         6 . The method of  claim 5 , wherein the differential air pressure system comprises an exercise machine, and the pressure versus pain relationship is used to control operation of the exercise machine. 
     
     
         7 . The method of  claim 6 , wherein the exercise machine comprises a treadmill, and the pressure versus pain relationship is used to control at least one of a speed of the treadmill and an incline of the treadmill. 
     
     
         8 . The method of  claim 6 , wherein the exercise machine comprises a stepper machine, and the pressure versus pain relationship is used to control a resistance of the stepper machine. 
     
     
         9 . The method of  claim 6 , wherein the exercise machine comprises a stationary bicycle, and the pressure versus pain relationship is used to control a resistance of the stationary bicycle. 
     
     
         10 . An apparatus to predict effective body weight of a user versus system pressure, the apparatus comprising:
 a differential air pressure system comprising a user interface and a chamber configured to receive and surround at least a portion of a user's body; and   a processor coupled with the differential air pressure system, the processor configured to adjust pressure in the chamber, to receive a pain indication from the user via the user interface, and to construct a pain versus chamber pressure relationship for the user.   
     
     
         11 . The apparatus of  claim 10 , wherein the pain versus chamber pressure relationship is used to control operation of an exercise machine included in the differential air pressure system. 
     
     
         12 . A method of calibrating a differential air pressure system for predicting effective body weight of a user versus system pressure, the method comprising:
 surrounding at least a portion of a user's body with a chamber of a differential air pressure system, wherein the differential air pressure system comprises a sensor configured to sense whether the user's body within the chamber is in physical contact with a surface;   adjusting pressure in the chamber until a lift-off pressure is reached, the lift-off pressure being a pressure at which the sensor detects a break in the physical contact between the user's body and the surface; and   using the lift-off pressure to calibrate pressure in the chamber.   
     
     
         13 . The method of  claim 12 , wherein the lift off pressure can be used to determine a chamber pressure required to result in a desired effective body weight for the user. 
     
     
         14 . The method of  claim 12 , wherein the lift off pressure used to determine a maximum safety chamber pressure for the user to prevent lift off during usage. 
     
     
         15 . An apparatus to predict effective body weight of a user versus system pressure, the apparatus comprising:
 a differential air pressure system that includes a chamber to receive and surround at least a portion of a user's body and a sensor configured to detect whether the user's body within the chamber is in physical contact with a surface; and   a processor coupled with the differential air pressure system, the processor configured to inflate the chamber of the differential air pressure system, and to measure a lift-off pressure at which the sensor detects that physical contact between the user's body and the surface has been broken.   
     
     
         16 . A method of calibrating a differential air pressure system for predicting effective body weight of a user versus system pressure, the method comprising:
 using gas to pressurize a chamber in a differential air pressure system, the chamber surrounding at least a portion of a user's body; and   using a flow rate of gas into and/or out of the chamber to determine pressure in the chamber.   
     
     
         17 . The method of  claim 16 , comprising using an exhaust valve position or opening to determine pressure in the chamber. 
     
     
         18 . The method of  claim 16 , comprising using voltage and/or current drawn by a blower pumping gas into the chamber to determine a pressure in the chamber. 
     
     
         19 . A method of calibrating a differential air pressure system for predicting effective body weight of a user versus system pressure, the method comprising:
 measuring an effective body weight of a user having at least a portion of the user's body surrounded by a chamber of a differential air pressure system by measuring a startup current and/or voltage of a motor of an exercise machine supporting the user's body within the chamber; and   correlating the effective body weight of the user with pressure in the chamber.   
     
     
         20 . The method of  claim 19 , comprising measuring pressure in the chamber using a flow rate of gas into and/or out of the chamber.