Origami-inspired metamorphous structures can adjust their shapes and mechanical behaviors according to operational requirements. However, they are typically composed of nonrigid origami, where required facet deformation complicates actuation and makes them highly material dependent. In this study, we present a type of origami metamorphous structure composed of modular bistable units, each of which is a rigid origami. The elasticity within the origami creases and switching of mountain and valley crease lines enable it to have bistability. The resultant metamorphous structure has multistability, allowing it to switch among multifarious configurations with programmable profiles. This concept was validated by potential energy analysis and experiments. Using this concept, we developed a robotic limb capable of both lifting and gripping through configuration changes. Furthermore, we used the origami units to construct a metamaterial whose properties could change with the variation of configurations. These examples demonstrate the concept’s remarkable versatility and potential for many applications.

Capturing noncooperative targets in space has great prospects for aerospace application. In this work, the knuckle unit of a large-scale reconfigurable space multifingered hand (LSRSMFH) for multitask requirements is studied. A plurality of knuckle units is connected in series to form a finger of the LSRSMFH. First, the lockable spherical (lS) joint, a new metamorphic joint that can function as a Hooke (lS₁) or spherical (lS₂) joint and is driven by shape memory alloy (SMA) material, is proposed. Based on the lS joint, this paper presents a new metamorphic parallel mechanism (MPM) (i.e., 3RRlS MPM), which has four configurations, namely, 3RRlS₁, 3RRlS₂, 2RRlS₁-RRlS₂, and 2RRlS₂-RRlS₁ configuration. The degree-of-freedom (DOF), overconstraint, and parasitic motion of the 3RRlS MPM are analyzed using screw theory, of which the DOF can be changed from 1 to 3. The 3RRlS₁ configuration has a virtual constraint, and the 3RRlS₂ configuration has parasitic motions. The results indicate that the mechanism motion screws can qualitatively represent the mechanism parasitic motions, and it is verified by deriving the kinematic equation of the 3RRlS MPM based on its spatial geometric conditions, the workspace of the 3RRlS MPM is further solved. The kinematic analysis indicates that the 3RRlS MPM can realize the folding, capturing, and reconfiguring conditions of the LSRSMFH.

Composite ultra-thin boom can be folded elastically. Moreover, such booms are able to self-deploy by releasing stored strain energy, which can be applied in deployable antenna, solar sail, and optical telescopes. Surrogate models for imperfection-sensitive quantities of interest and multi-objective optimization are developed for the design of a new N-shape cross-section composite ultra-thin deployable boom. The proposed optimal design method integrates four general steps: (1) design of experiments, wherein the sampling designs of the N boom are created on the basis of the two-factor five-level full factorial design of experiments method; (2) efficient computational analyses of each design sample, wherein the post-buckling behavior of the N boom are analyzed under three different axial directions using nonlinear finite element ABAQUS/Explicit solver; (3) establishing the surrogate models of bending stiffness around the x-and y-axes and torsional stiffness around the z-axis by response surface method (RSM); (4) performing the multi-objective optimization design using modified non-dominated sorting genetic algorithm to realize the optimal design. The bending stiffness around the x-and y-axes and the torsional stiffness around the z-axis are set as the objectives, mass is set as the constraint, and the bonded web height and the central angle of the middle tape spring of the N boom are set as the variables. The typical surrogate modeling method can be applied to different problems in structural and material design.