This paper presents a topological and dimensional kinematic synthesis methodology that can be used to constrain the movement of kinematic planar, spherical, and spatial revolute–revolute dyads (RR dyads). The approach is inspired by a subcategory of origami called rigid origami, which deals with highly overconstrained spatial deployable linkages. An example is the Miura-ori folding pattern used to deploy solar panels in space. In addition to this application, this linkage also provides an interesting way to constrain general RR dyads so that they perform a single DOF motion. Here, these mechanisms are called origami-guided RR chains, and computer aided design models (CAD) of the planar, spherical and spatial type are presented. The dimensional synthesis approach allows us to constrain consecutive links using R or C joints so that the links satisfy two arbitrarily predefined task positions. This leads to what we call the two-configuration synthesis of linkages, and we examine a concrete synthesis procedure for an origami-guided spatial RR chain, which is also built using rapid prototyping. The procedure actually combines the two-configuration synthesis approach with the synthesis of the spatial TS dyad, and the paper provides an outlook on further ways to apply the two-configuration synthesis and also to synthesize the origami-guided RR chains.

The concept presented in this paper describes two new approaches to integrate transfer support functions into wheelchairs. The goal is to relieve caregivers and nurses in their daily task of lifting patients from and to the wheelchair without the need of an additional external lift device, such as commonly used lifting cranes or lifting belts. The contributions of this paper are (i) the design of two different mechanical linkages, which realize two types of transfer motions, (ii) the selection of a passive actuator for weight compensation and simulation of the force induced by it (static design), as well as (iii) the experimental evaluation of the simulation using rapid prototyping functional models of the concepts. The results are two different design concepts, each of which can realize a particular, smooth transfer motion.

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This paper discusses the use of concepts of finite rigid body kinematics as well as kinematic synthesis in non-rigid, engineering folding problems. The exemplary task consists in designing a folding pattern, which allows to fold a circular sheet from a flat unfolded state into a prescribed compact spatial configuration that forms a hexagonal prism. Other two-configuration design problems may be found for instance in space applications where membranes in tensegrity reflector antennas need to be stowed in a spacecraft. The folding motion could be actuated using an appropriately designed linkage mechanism attached to the membrane, which, however, is not considered in this paper. The specific result of this work is a creative but systematic and computational procedure for crease pattern design. The approach is essentially based on the relative kinematics equations of serial kinematic chains and the finite position synthesis of linkage building blocks. These techniques sucessively combine to segment a flat bounded surface, such that it can reach the prescribed spatial configuration.

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