A Spatial Mechanism for the Measurement of the Inertia Tensor: Theory and Experimental Results

This paper deals with the problem of measuring the inertia tensor of rigid bodies. An original approach is adopted, different from classical modal analysis techniques. The rigid body is forced by a spatial mechanism to rotate around different axes. Once the mechanism is calibrated, i.e., its inertia and stiffness matrices are known, the inertia tensor of the rigid body may be determined by measuring the frequencies of the small oscillations around the selected axes and then solving a least-squares identification problem. Two prototypes of the spatial mechanism were built. The first was used to perform tests and to measure the inertia tensor of some compressors for domestic refrigeration. The second was constructed to measure the inertia tensor of large mechanical systems.