An external force estimation device is configured to estimate an external force acting on a motor. The external force estimation device includes a processor. The processor is configured to: calculate an output torque of the motor by using a value of a current supplied to the motor; estimate an inertia torque of the motor by using rotational position information of the motor; estimate a first friction torque of the motor by using the rotational position information of the motor; perform temperature-based correction for the first friction torque by using temperature information of the motor; and estimate the external force by subtracting the inertia torque and the first friction torque after the temperature-based correction from the output torque.

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 bicycle crankarm the bicycle transmission side that has a main body length measured along a length from a crankset's crankarm rotation axis to a pedal axis. The crankarm has at least one stress/strain detector oriented along the length direction at a fixed distance, measured from the center of the stress/strain detector to the rotation axis of the crankarm, such that the ratio of the distance and the length is in the range between 0.45-0.65.

A bicycle crankarm the bicycle transmission side that has a main body length measured along a length from a crankset's crankarm rotation axis to a pedal axis. The crankarm has at least one stress/strain detector oriented along the length direction at a fixed distance, measured from the center of the stress/strain detector to the rotation axis of the crankarm, such that the ratio of the distance and the length is in the range between 0.45-0.65.

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 device for measuring horological shakes, including a structure carrying an articulated mechanism with a compliant mechanism having a linear force/stroke characteristic connecting a first fixed element to a second element capable of moving linearly under the effect of an actuator manoeuvring same in a contactless manner in both directions, and a position sensor determining the position of the second element in a direction, and a load sensor determining the variation in the axial pushing or pulling load of the second element carrying a gripper clamping a mobile component, and/or the variation in the gradient of this load, generating a signal for triggering the position measurement during each sudden change in gradient of the load in each direction of running, to determine the shake of the mobile component, by comparing the positions measured during the sudden changes in gradient during the outward and return strokes.

A device for measuring horological shakes, including a structure carrying an articulated mechanism with a compliant mechanism having a linear force/stroke characteristic connecting a first fixed element to a second element capable of moving linearly under the effect of an actuator manoeuvring same in a contactless manner in both directions, and a position sensor determining the position of the second element in a direction, and a load sensor determining the variation in the axial pushing or pulling load of the second element carrying a gripper clamping a mobile component, and/or the variation in the gradient of this load, generating a signal for triggering the position measurement during each sudden change in gradient of the load in each direction of running, to determine the shake of the mobile component, by comparing the positions measured during the sudden changes in gradient during the outward and return strokes.

Drive shaft monitoring system has a first and second coded disc. The first and second coded disc are provided with multiple slots or recesses evenly distributed in circumferential direction thereof. The drive shaft monitoring system includes at least two independent light sensor assemblies arranged in connection with the slots or recesses of the first and second coded disc.

This disclosure presents a dimensionless relationship between a fluid flow rate, a viscosity, and a brake horsepower (BHP) in a pump operation and a method that uses the dimensionless relationship to predict a BHP for viscous performance of a pump from water performance specifications. Using the dimensionless relationship, i.e., K-R number, the methods determine a BHP correlation that allows the prediction of the BHP specification to satisfy a pump performance metric at any given speed, flow rate, and viscosity. This prediction can be calculated from water performance specifications without physically testing the pump in the viscous implementation environment.

This disclosure presents a dimensionless relationship between a fluid flow rate, a viscosity, and a brake horsepower (BHP) in a pump operation and a method that uses the dimensionless relationship to predict a BHP for viscous performance of a pump from water performance specifications. Using the dimensionless relationship, i.e., K-R number, the methods determine a BHP correlation that allows the prediction of the BHP specification to satisfy a pump performance metric at any given speed, flow rate, and viscosity. This prediction can be calculated from water performance specifications without physically testing the pump in the viscous implementation environment.