Design and Control Concept for Reconfigurable Architecture

Abstract

Shape-control in an architectural context is expected to provide unique opportunities for buildings with enhanced functionality, flexibility, energy performance, and occupants comfort. An architectural concept is proposed which consists of a parallel arrangement of planar n-bar mechanisms formulating its skeleton structure and a membrane material stretched over it to define the building envelope. Overall shape changes involve coordinated motion of the individual planar mechanisms. Each linkage is equipped with one motion actuator as well as brakes installed on every joint. Reconfigurations of the building are based on the “effective 4-bar (E4B)” concept allowing stepwise adjustments. Each intermediate step involves the selective locking of (n − 4) joints on each closed-loop linkage effectively reducing it to a single degrees-of-freedom (DOF) 4-bar mechanism, the configuration of which can be adjusted using the available motion actuator. A reconfiguration of the mechanism can be realized through alternative control sequences and an optimal one can be selected based on specific criteria. The paper reports the fundamental design and control concepts. A simulation and an experimental study are presented to demonstrate the implementation of the general reconfiguration approach and examine relevant issues.

Design, motion planning and control of a reconfigurable hybrid structure

“…When the Jacobian matrices drop rank the mechanism encounters a singularity [45]. Singularities may create anomalies to the intended operation of a linkage and need to be considered in motion planning.…”

“…The basic reconfiguration control procedure based on the E4B concept has already been implemented and tested using simulations and experiments as described in [45,48,49] using a small-scale prototype. During the experiments, a single stepper motor actuator was used and electromagnetic brakes (spring loaded, fail-safe) were installed at the rest of the joints.…”

“…wind conditions). In order to select between alternative reconfiguration sequences, motion planning may also incorporate an optimization procedure [45]. The controller is supplied with reconfiguration sequence information from the motion planning routine.…”

“…The reconfigurable structure presented herein builds upon adaptable architecture concepts as well as approaches to motion planning and control of multibody systems previously developed by the authors [43][44][45]. The proposed structural system consists of hinge-connected beams and a secondary system of struts and cables, as described in the following section.…”

On the morphology of reconfigurable hybrid structures based on the effective 4-bar mechanism

“…The authors had been engaged in the conceptual development of an adaptable structure of spatial hinge connected beams and three planar secondary members rotated at a relative angle of 120°, on the transverse plane of the primary members [20]. Relevant motion planning principles of such linkage systems have been conceived based on a basic planar 7-bar system, which was experimentally tested in small scale [21]. In parallel, a planar 9-bar hybrid system has been investigated in its static and kinetic behaviour on the basis of a structure, supported and controlled through a secondary system of struts and continuous cables with variable length.…”