A power measurement device, which may be mounted to an inside area of a crank arm, includes processing circuitry within a housing. The processing circuitry is coupled with strain gauges mounted on the crank arm, and produces a power value that is wireless transmitted to a separate display that may receive and display power measurements. The housing may include a mounted portion and a cantilever portion where the mounted portion houses the processing circuitry and the cantilever portion houses batteries supply energy for the processing circuitry and other features.

A method for determining an efficiency and/or calibrating a torque of a drivetrain comprises two tests. The drivetrain has a motor-side end at a main shaft connectable to a motor and a generator-side end, with a generator arranged between the ends. In a first test, the motor-side end of the drivetrain is driven. A variable dependent on the main shaft torque is determined at the motor-side end of the drivetrain and an electrical power Pelec is determined at the generator-side end of the drivetrain. In a second test, the generator-side end of the drivetrain is driven and the variable dependent on the main shaft torque is determined at the motor-side end and the electrical power is determined at the generator-side end. An efficiency and/or calibration parameters is/are determined from the electrical power values and the variables dependent on the main shaft torque determined in the first test and second tests.

A method of calibrating a crank arm-mounted power meter includes receiving an angle measurement from a first sensor disposed on a crank arm, the angle measurement corresponding to an angular orientation of the crank arm. A predicted load measurement is then calculated based on the angle measurement and weight data for the crank assembly including the crank arm and stored in memory. A load measurement corresponding to a load on the crank arm is obtained and a zero offset value is then calculated by determining a difference between the predicted load measurement and the load measurement. Power calculation logic for determining power applied to the crank arm is then updated using the zero offset value.

A power measurement assembly mounted within an axle. In a specific example, the axle is a spindle that is interconnects the cranks of a bicycle, exercise, bicycle, or other fitness equipment. The power measurement assembly may include strain gauges connected with an appropriate circuit (e.g., Wheatstone bridge) that provides an output of the force on the axle by a rider pedaling the crank. In the case of an axle, the strain gauges measure the torsion due to the applied torque on the crank. The value is converted to a power value by a processor and that value is then wirelessly transmitted for display. The processor and/or the transmitter may be mounted within the axle. A separate power measurement assembly may be mounted on one of the cranks, which may include its own processor and transmitter or may take advantage of the processor and transmitter within the axle.

The embodiments disclosed herein relate to a bracket for a valve system, having an actuator side of the bracket, defining a first set of one or more holes; a valve side of the bracket, wherein the valve side is opposite the actuator side, and further wherein the valve side defines a second set of one or more holes; a wall connecting the actuator side and the valve side; and a strain gauge mounted to the wall.

A bicycle crank arm apparatus comprises a crank arm having a crank axle mounting portion and a pedal mounting portion. A circuit-mounting structure is disposed between the crank axle mounting portion and the pedal mounting portion, wherein the circuit-mounting structure is configured to detachably mount a measurement board. When a measurement board is mounted to the circuit-mounting structure, the resulting combination forms a bicycle input force processing apparatus.

A method of adjusting the closing force of a door coupled to a door closer assembly having a bias element. The method includes determining the kinetic energy of the door without using the weight or other dimensions of the door. The determined kinetic energy is used to adjust the closing force of an electro-mechanical door closer that includes a spring and a motor. The door includes the use of one, some of, or all of an accelerometer, an angular position sensor, a time to close, a breaking torque, and a controller to identify values a acceleration, velocity, and/or position of the door. The identified values are provided to the controller, which is configured to calculate the kinetic energy of the door. The calculated kinetic energy is used to determine the closing velocity of the door closure to ensure proper operation of the door at the point of installation.

A bicycle trainer compensation algorithm based on multi-groove belts sliding relative to one another includes: determining a load interval and a rotating speed range, recording an external driving torque, a rotating speed, a measured torque and a no-load mechanical loss of the bicycle trainer under conditions of different loads and different rotating speeds, and obtaining a relationship between a mechanical loss of a whole machine and the different rotating speeds, the different loads, and the no-load mechanical loss, fitting a plurality of sets of relationships to obtain an algorithm relation, verifying universality of the algorithm relation, and further fitting to obtain a compensation algorithm relation, and verifying whether a compensation accuracy of the compensation algorithm relation is satisfied within an error requirement.

The present application relates to a method for determining an efficiency and/or for calibrating a torque of a drivetrain (1), in particular a drivetrain (1) of a wind turbine. The method for determining an efficiency and/or for calibrating a torque of a drivetrain (1), in particular of a drivetrain of a wind turbine, is particularly suited for carrying out on a test rig and comprises two tests. The drivetrain has a motor-side end at a main shaft connectable to a motor and a generator-side end, between which ends a generator is arranged. In a first test, the motor-side end of the drivetrain (1) is driven. A variable dependent on the main shaft torque is thereby determined at the motor-side end of the drivetrain (1) and an electrical power P.sub.elec is determined at the generator-side end of the drivetrain (1). In a second test, the generator-side end of the drivetrain (1) is driven and the variable dependent on the main shaft torque is likewise determined at the motor-side end and the electrical power P.sub.elec is determined at the generator-side end. An efficiency and/or calibration parameters is/are determined from the electrical power values and the variables dependent on the main shaft torque determined in the first test and in the second test.

A bicycle trainer compensation algorithm based on multi-groove belts relatively sliding to one another includes: determining a load interval and a rotating speed range, recording an external driving torque, a rotating speed, a measured torque and a no-load mechanical loss of the bicycle trainer under conditions of different loads and different rotating speeds, and obtaining a relationship between a mechanical loss of a whole machine and the rotating speed, the load, and the no-load mechanical loss, fitting a plurality of sets of relationships to obtain an algorithm relation, verifying universality of the algorithm relation, and further fitting to obtain a compensation algorithm relation, and verifying whether a compensation accuracy of the compensation algorithm relation is satisfied within an error requirement.