Automatic Control Techniques For A Treadmill

Abstract

A treadmill includes a moveable belt and a controller configured to cause the belt to move in accordance with a target speed. The controller is further configured to receive information indicative of a current gradient of the belt and to automatically adjust the value of the target speed in dependence on the current gradient of the belt.

What is claimed is: 
     
         1 . A treadmill comprising:
 a moveable belt; and   a controller configured to:
 cause the belt to move in accordance with a target speed, 
 receive information indicative of a current gradient of the belt, and 
 automatically adjust the value of the target speed in dependence on the current gradient of the belt. 
   
     
     
         2 . The treadmill of  claim 1 , wherein the controller is configured to receive an input speed for the belt and to automatically adjust the value of the target speed in dependence on the input speed and the current gradient of the belt. 
     
     
         3 . The treadmill of  claim 2 , wherein the controller is configured such that, when the current gradient of the belt is greater than zero, the controller is configured to automatically adjust the value of the target speed such that the target speed is less than the input speed. 
     
     
         4 . The treadmill of  claim 3 , wherein the controller is configured such that, when the current gradient of the belt is zero, the controller is configured to automatically set the target speed equal to the input speed. 
     
     
         5 . The treadmill of  claim 3 , wherein the controller is configured such that, when the current gradient of the belt is less than zero, the controller is configured to automatically set the target speed equal to the input speed. 
     
     
         6 . The treadmill of  claim 2 , wherein the controller is configured to receive information indicative of a change in the input speed and to automatically adjust the target speed in dependence on the input speed, the change in the input speed, and the current gradient of the belt. 
     
     
         7 . The treadmill of  claim 1 , further comprising:
 a motor,   wherein the belt is driven by the motor, and   wherein the controller is configured to cause the motor to generate torque as required to cause the belt to move in accordance with the target speed.   
     
     
         8 . The treadmill of  claim 1 , wherein the controller is configured to receive an input gradient for the belt and to cause the belt to move from a first position to a second position in which the belt is tilted at the input gradient. 
     
     
         9 . The treadmill of  claim 8 , further comprising:
 a tilt sensor configured to sense the current gradient of the belt,   wherein the controller is configured to receive information indicative of the current gradient of the belt from the tilt sensor, and   wherein the controller is configured to automatically adjust the value of the target speed in dependence on the current gradient of the belt, even when the current gradient of the belt is different from the input tilt angle.   
     
     
         10 . The treadmill of  claim 8 , further comprising:
 a linear actuator,   wherein the controller is configured to cause the linear actuator to extend or retract as required to move the belt from the first position to the second position.   
     
     
         11 . The treadmill of  claim 1 , wherein the controller is configured compare the current gradient of the belt to a predefined gradient limit and to automatically adjust the value of the target speed in dependence on the lowest value of the current gradient and the predefined gradient limit. 
     
     
         12 . The treadmill of  claim 1 , wherein the controller is configured to automatically adjust the value of the target speed by dividing the target speed by a grade adjusted speed (GAS) factor,
 wherein, when the current gradient of the belt is greater than or equal to 0% and less than or equal to 10%, the GAS factor is calculated according to the following equation:   
       
         
           
             
               
                 
                   
                     
                       
                         G 
                         ⁢ 
                         A 
                         ⁢ 
                         S 
                         ⁢ 
                             
                         factor 
                       
                         
                       = 
                         
                       
                         
                           a 
                             
                           · 
                             
                           
                             gradient 
                             2 
                           
                         
                           
                         + 
                           
                         
                           b 
                             
                           · 
                             
                           gradient 
                         
                           
                         + 
                           
                         1 
                       
                     
                     , 
                   
                 
                 
                   
                     ( 
                     1 
                     ) 
                   
                 
               
             
           
         
         wherein, when the current gradient of the belt is greater than 10%, the GAS factor is calculated according to equation (2): 
       
       
         
           
             
               
                 
                   
                     
                       
                         G 
                         ⁢ 
                         A 
                         ⁢ 
                         S 
                         ⁢ 
                             
                         factor 
                       
                         
                       = 
                         
                       
                         
                           a 
                             
                           · 
                             
                           
                             gradient 
                             2 
                           
                         
                           
                         + 
                           
                         
                           b 
                             
                           · 
                             
                           gradient 
                         
                           
                         + 
                           
                         1 
                       
                     
                     , 
                         
                     and 
                   
                 
                 
                   
                     ( 
                     2 
                     ) 
                   
                 
               
             
           
         
         wherein 0.001≤a≤0.002 and 0.01≤b≤0.03. 
       
     
     
         13 . The treadmill of  claim 1 , wherein the controller is further configured to automatically adjust the value of the target speed in dependence on a distance of a user on the treadmill from a predefined target position on the treadmill. 
     
     
         14 . The treadmill of  claim 1 , wherein the controller is configured to:
 cause the belt to move to a position in which the belt is tilted at a target gradient, and   automatically adjust the value of the target gradient in dependence on the time derivative of the target speed of the belt and the gravitational acceleration constant.   
     
     
         15 . A treadmill comprising:
 a moveable belt; and   a controller configured to cause the belt to move in accordance with a target speed and a target gradient and to receive information indicative of a current gradient of the belt, the controller comprising a grade adjusted speed (GAS) module configured to calculate a grade adjusted speed for the belt in dependence on the current gradient of the belt and the target speed of the belt, the controller being configured to automatically adjust the target speed of the belt in dependence on the grade adjusted speed calculated by the GAS module.   
     
     
         16 . The treadmill of  claim 15 , wherein the controller further comprises a free run module configured to calculate an adjusted target speed for the belt in dependence on a previous target speed of the belt and a distance of a user on the treadmill from a predefined target position on the treadmill, wherein the GAS module is configured to calculate a grade adjusted speed for the belt in dependence on the current gradient of the belt and the adjusted target speed for the belt, and wherein the controller is configured to automatically adjust the target speed of the belt in dependence on the adjusted target speed calculated by the free run module and the grade adjusted speed calculated by the GAS module. 
     
     
         17 . The treadmill of  claim 15 , wherein the controller further comprises a simulated inertial module configured to calculate an adjusted gradient angle for the belt in dependence on the time derivative of the target speed, the gravitational acceleration constant, and the target speed or the grade adjusted speed for the belt, and wherein the controller is configured to automatically adjust the target gradient of the belt in dependence on the adjusted target gradient calculated by the simulated inertial module. 
     
     
         18 . A computer-implemented method for controlling a treadmill, the method comprising:
 driving, by a controller, a motor of the treadmill in accordance with a target speed, the motor being operatively coupled to a moveable belt of the treadmill;   receiving, by the controller, a change in a gradient of the belt;   computing, by the controller, an adjusted value for the target speed of the motor based on the change in the gradient of the belt; and   automatically adjusting, by the controller, the target speed of the motor in accordance with the adjusted value for the target speed.