A Portable device for measuring the cog: Design, error analysis and calibration

The paper is devoted to the design, error estimation and calibration of a portable device for the measurement of the centre of gravity of rigid bodies. The device consists in a simple but effective implementation of the knife edge method. The design of the device including safety considerations is fully described. An error estimation approach is employed in the very early stage of the design to assess the required instrumentation accuracy and the manufacturing tolerances. A calibration of the portable device is performed by means of proper calibrated masses. After calibration, the accuracy of the device corresponds to the target accuracy defined in the a-priori error analysis. The design procedure described in the paper shows a straightforward approach for the design of devices for the measurement of the inertia properties. By such a procedure, it is possible to identify the most critical design areas and make the correct choices in the early stage of the design process. Also, a deep understanding of the measuring process can be gained allowing the definition of an effective calibration procedure.