ELSEVIER Measurement 16 (1995) 241-254 Measurement Measurement of the inertia tensor: An experimental proposal * A. Gentile, L. Mangialardi, G. Mantriota*, A. Trentadue Department of Industrial Design and Production, Polytechnic of Bari, Hale Japigia 182, 70126 Bari, Italy Abstract The presence of robots in advanced automated processes relies on the use of end-effectors capable of picking up and manipulating objects with different geometrical and mechanical characteristics. The position of the centre of mass and the inertia tensor are some of the parameters necessary for the design of gripping devices and especially for a dynamic study of manipulation. This paper describes the experimental setup used to measure the inertia tensor and the position of the centre of mass of unpredefined objects. The unit employed is equipped with transducers and accelerometers, and is capable of recording the dynamic response of an unpredefined object to a known motion. The data are acquired by means of a multiprogrammer and are then processed by a personal computer. The computer thus provides the components of the principal tensor of inertia, the direction cosines of the principal reference frame with respect to a predefined barycentric system, and the position of the centre of mass. After defining the measurement set the experimental unit relied on, the paper goes on to present the expressions for the measurement errors made in estimating the parameters considered. Keywords: Inertia tensor determination; Centre of mass; Measurement error 1. Introduction The more widespread use of robots in new automated processes calls for a specific study of the gripping devices employed, and of their control in consideration of the different types of objects to be handled [ 1,2]. The dynamic study of any object to be picked up or handled relies on the inertial properties of that object, namely its mass and inertia tensor. Our department is currently studying the use of robots in automated postal services, especially in some parcel sorting procedures. Generally parallelepipedal in shape, postal parcels have widely varying sizes and are considerably dishomogeneous. Hence, the determination of the characteristic parameters of the robot, and especially of the dextrous gripping devices, calls for an experimental investigation on a random sample where both the medium and the maximum values of the geometrical and inertial properties of the parcels may be determined. In the study of automated processes, such an investigation is instrumental in estimating the magnitude of dynamic stresses exerted on manipulated objects. * Research supported by Progetto Finalizzato C.N.R. "Robotica" (C.N.R. 91.01970.PF67). * Corresponding author. 0263-2241/95/$09.50 (E) 1995 Elsevier Science B.V. All rights reserved SSDI 0263-224 1 (94) 00030-B