Simultaneous Displacement and Internal Force Prescription in Shape Control of Pin-Jointed Assemblies

Abstract

This paper presents a direct method for controlling nodal displacements, internal bar forces, and simultaneously both nodal displacements and internal bar forces, of a prestressable pin-jointed assembly under load. The method is aimed at static shape control of geometrically sensitive structures through length actuations in selected bars. The paper discusses identification of the most effective bars for actuation so that the desired shape can be obtained, without incurring violation in bar forces, through both a minimal number of actuators and minimum actuation in those actuators. The method can also be used for adjustment of bar forces to either reduce instances of high forces or increase low forces (e.g., in a cable nearing slack).