The Generation and Measurement of Arbitrarily Directed Forces and Moments: the Project of a Multicomponent Calibration Device Based on a Hexapod Structure

摘要

In the metrology of the mechanical quantities of force and torque, standard machines are used that allow these components to be generated in a given direction. For force in most cases this is the vertical, for torque both the horizontal or the vertical directions are in use. In contrast to this realization, for some applications it is necessary to generate forces or moments in arbitrary directions. Moreover, the standard machines generate only one main component and in addition small disturbing components. But it is often desired to have a superposition of forces and moments without a main component. The present work describes a new method of generating and measuring arbitrary directed forces and moments using a set of six drives on one side of the machine and six force transducers on the other. Both the drives and the force transducers are arranged in a hexapod structure. A theoretical overview is followed by a description of the general design of the machine. Some optimization procedures show the dependence on the chosen geometry of the load decomposition into the six forces. Due to the limited stiffness of the transducers and the structural parts of the machine, the set of equations describing the system must be found by a process of iteration. Some considerations relating to the practical realization conclude the paper.