Dynamic torquemeter calibration of bicycle ergometers

Bicycle ergometers as widely used in both clinical testing and exercise physiology studies are mechanical, hydraulic, or electromechanical devices. They are thus subject to change and error, creating a need for repeated calibration. We have developed a compact inexpensive torquemeter that permits dynamic calibration of the entire range of an ergometer. The torquemeter continuously measures the input torque at the pedal shaft of the ergometer and thus includes all work done in the drivetrain. It also permits adjustment of electrically braked ergometers to a specified torque using internal adjustments to give correct scale readings. The torquemeter depends on a high carbon steel torsion spring whose ends are rotated in angular deflection by increasing applied torque. Relative rotation is sensed through a multiturn potentiometer, the resistance of which is measured externally through a slip ring contact.