Design, motion planning and control of a reconfigurable hybrid structure

Abstract

Compared to traditional fixed-shaped structures, reconfigurable structures may provide various advantages with regard to space utilization, building form optimization and energy efficiency. The purpose of this study is to present the development and kinematic behavior of a reconfigurable hybrid structure. Hinge-connected beam members, stabilized through a secondary system of struts and continuous diagonal cables compose planar n-bar mechanisms arranged in parallel to formulate the spatial reconfigurable structure. The transformability of the system is based on the application of the ‘effective 4-bar’ concept using a sequence of 1-DOF motion steps through selectively locking (n−4) joints of the primary members and modification of the cables’ length. Different intermediate configurations depend on the motion planning, in order to adjust the system’s joints to the desired values during the motion steps involved in the respective transformation sequence. The proposed control system includes position sensors installed on the individual joints to provide feedback information, two motion actuators located at the structural supports, as well as brakes installed on each individual joint. The control system manages the operation of the motion actuators and the brakes to realize the reconfiguration sequences through tensioning the cables. The paper reports the structure’s design concept, motion planning and control. The implementation of the structural reconfiguration approach and related kinematics issues are investigated through a simulation example.