Power measurement device for a bike trainer

Abstract

Systems and methods for accurately measuring power output of a cyclist using a bike trainer that may be operated by a user for stationary riding when coupled to a conventional bicycle. The systems utilize a power output equation that models power due to resistance of a fan of the bike trainer as well as power due to kinetic energy of the fan. The systems account for operating conditions that affect the power measurements so that more accurate measurements can be provided, thereby improving the training experience of the user. Operating conditions include mechanical drag, temperature, humidity, and atmospheric pressure and/or altitude. The power output equation is dependent on the angular velocity of the fan of the bike trainer and the measured or received operating conditions.

1 . A power measurement device for a bike trainer, the bike trainer being usable as a training device when coupled to a conventional bicycle, the bike trainer comprising a fan rotatably coupled to the bicycle through a freewheel mechanism, the power measurement device comprising:
 a velocity sensor operative to obtain measurements indicative of the angular velocity of the fan; and   a power console unit operative to receive measurements from the velocity sensor and, based on the received measurements, to calculate an output power of a user operating the bike trainer dependent an operating condition of the bike trainer and the kinetic energy of the fan.   
     
     
         2 . The power measurement device of  claim 1 , wherein the power console unit is operative to receive measurements from the velocity sensor wirelessly. 
     
     
         3 . The power measurement device of  claim 1 , wherein the power console unit further comprises a display operative to display the calculated output power. 
     
     
         4 . The power measurement device of  claim 1 , wherein the power console unit comprises a sensor operative to sense one or more operating conditions of the bike trainer, and wherein the power console unit is operative to receive signals from the sensor, and to modify the output power calculation dependent on the received signals. 
     
     
         5 . The power measurement device of  claim 4 , wherein the sensor comprises one of a temperature sensor, a humidity sensor, and an air pressure sensor. 
     
     
         6 . The power measurement device of  claim 1 , wherein the operating condition includes temperature, atmospheric pressure, or humidity. 
     
     
         7 . The power measurement device of  claim 1 , wherein the operating condition includes mechanical drag of the bike trainer. 
     
     
         8 . The power measurement device of  claim 7 , wherein the mechanical drag of the bike trainer is determined by measuring the time required for the fan to spin down from a first angular velocity to a second, lower angular velocity. 
     
     
         9 . The power measurement device of  claim 1 , wherein the operating condition includes atmospheric pressure, and wherein the power console unit comprises an input device operative to allow a user to input an altitude value. 
     
     
         10 . The power measurement device of  claim 1 , wherein the power console unit comprises an input device operative to allow a user to input one or more operating conditions of the bike trainer. 
     
     
         11 . The power measurement device of  claim 10 , wherein the input device is operative to allow a user to input an altitude value of the bike trainer, and wherein the power console unit is operative to calculate the output power of the bike trainer dependent upon the altitude value. 
     
     
         12 . The power measurement device of  claim 1 , further comprising at least two sensors operative to sense two or more operating conditions of the bike trainer, wherein the power console unit is operative to calculate the output power of the bike trainer by utilizing a power equation that is modified dependent on the sensed operating conditions. 
     
     
         13 . The power measurement device of  claim 12 , wherein the power equation takes into account both power due to air resistance of the fan and due to the kinetic energy of the fan. 
     
     
         14 . A power measurement device for a bike trainer, the bike trainer being usable as a training device when coupled to a conventional bicycle having its rear wheel removed, the bicycle including a frame that includes rear dropouts, the bike trainer comprising:
 a frame;   a first drive member rotatably mounted on a first side of the frame on a laterally extending first axle, the first axle being configured for selective coupling with the rear dropouts of the bicycle;   a freewheel mechanism including a first portion engaged with the first drive member, the freewheel mechanism further including a second portion engaged with a sprocket configured to interface with a chain of the bicycle when the bicycle is coupled to the bike trainer, wherein the freewheel mechanism is operative to disengage the first portion from the second portion when the first portion rotates faster than the second portion in a forward direction;   a second drive member rotatably mounted on a first side of the frame on a laterally extending second axle;   a flexible drive member in driving engagement with and extending between the first drive member and the second drive member; and   a fan rotatably mounted on the second axle on a second side of the frame opposite the first side;   the power measurement device comprising:   a velocity sensor operative to obtain measurements indicative of the angular velocity of the fan; and   a power console unit operative to receive measurements from the velocity sensor and, based on the measurements, to calculate an output power of a user operating the bike trainer dependent on an operating condition of the bike trainer and the kinetic energy of the fan.   
     
     
         15 . The power measurement device of  claim 14 , wherein the power console unit further comprises a display operative to display the calculated output power to a user. 
     
     
         16 . The power measurement device of  claim 14 , wherein the power console unit comprises a sensor operative to sense one or more operating conditions of the bike trainer, and wherein the power console unit is operative to receive signals from the sensor, and to modify the output power calculation dependent on the received signals. 
     
     
         17 . The power measurement device of  claim 16 , wherein the sensor comprises one of a temperature sensor and a humidity sensor. 
     
     
         18 . The power measurement device of  claim 14 , wherein the operating condition includes temperature, atmospheric pressure, or humidity. 
     
     
         19 . The power measurement device of  claim 14 , wherein the operating condition include mechanical drag of the bike trainer 
     
     
         20 . The power measurement device of  claim 14 , wherein the power console unit comprises an input device operative to allow a user to input one or more operating conditions of the bike trainer. 
     
     
         21 . The power measurement device of  claim 14 , further comprising at least two sensors operative to sense two or more operating conditions of the bike trainer, wherein the power console unit is operative to calculate the output power of the bike trainer by utilizing a power equation that is modified dependent on the sensed operating conditions. 
     
     
         22 . The power measurement device of  claim 21 , wherein the power equation takes into account both power due to resistance of the fan and due to the kinetic energy of the fan. 
     
     
         23 . A method for measuring the power output of a user operating a bike trainer, the bike trainer being usable as a training device when coupled to a conventional bicycle, the bike trainer comprising a fan rotatably coupled to the bicycle through a freewheel mechanism, the method comprising:
 measuring the angular velocity of the fan as a user operates the bike trainer; and   calculating an output power of the user operating the bike trainer dependent on an operating condition of the bike trainer and the kinetic energy of the fan.   
     
     
         24 . The method of  claim 23 , further comprising receiving the angular velocity measurements at a power console unit wirelessly. 
     
     
         25 . The method of  claim 23 , further comprising displaying the calculated output power. 
     
     
         26 . The method of  claim 23 , further comprising sensing one or more operating conditions of the bike trainer, and modifying the output power calculation dependent on the one or more sensed operating conditions. 
     
     
         27 . The method of  claim 26 , wherein sensing one or more of the operating conditions comprises sensing temperature, sensing humidity, or sensing air pressure. 
     
     
         28 . The method of  claim 23 , further comprising determining the mechanical drag of the bike trainer by measuring the time required for the fan to spin down from a first angular velocity to a second, lower angular velocity. 
     
     
         29 . The method of  claim 23 , further comprising receiving input from the user indicative of one or more operating conditions of the bike trainer. 
     
     
         30 . The method of  claim 23 , further comprising sensing one or more operating conditions of the bike trainer, and calculating the output power by utilizing a power equation that is modified dependent on the sensed operating conditions.