Solution region synthesis methodology of planar eight-bar linkage for four specified positions of a 4R chain

The solution region methodology for solving the problem of four-bar linkage synthesis with four specified positions was extended to solve the problem of eight-bar linkage synthesis. The processes to build solution regions for synthesizing different types of eight-bar linkages are described, and the methods of building solution regions are divided into five types. First, the synthesis equation is derived, and the curve expressed by the synthesis equation is called the solution curve. Second, the process to build the spatial solution regions from the solution curves is detailed, and a new defect identification method is developed for building the spatial feasible solution region, which is a set of linkage solutions meeting four positions and excluding defects. Finally, linkage solutions that do not meet practical engineering requirements are eliminated from the spatial feasible solution region to obtain the useful spatial solution region. The examples demonstrate the feasibility of the proposed method. The proposed synthesis methodology is simple and easy to program, and provides reference for four specified position synthesis of other multi-bar linkages.

A Single Actuator Mechanism for Airfoil Shape Morphing

Presented in this paper is a single actuator mechanism for airfoil shape morphing. The said mechanism is designed as a linkage array that is driven by one actuator to provide multiple output points along the entire airfoil shape. This mechanism consists of two components, namely the shape adaptation linkage (SAL) and the connector linkage. Each connector is made up of a passive camber connector (PCC) or an active camber connector (ACC). The PCC conditions the output of an SAL while the ACC serves to create the camber morphing effect. The design method is proposed with three steps: Camber Mapping, Shape Adaptation Linkage Synthesis, and Connector Synthesis. The proposed method has been applied to design a number of NACA airfoils with camber morphing to demonstrate the effectiveness.

Towards the appropriate synthesis of the four-bar linkage

Uncertainties are an inherent element in all mechanisms, arising from the manufacturing and assembly process or even from the operation of the device. In terms of synthesis routines for mechanisms, uncertainties are generally neglected since they are difficult to account for. In this work, the concept of appropriate design is utilized to develop routines that can more easily account for uncertainties in the geometrical parameters. These routines have been developed for linkages, specifically the four-bar linkage, and are capable of synthesizing the complete set of design solutions, referred to as allowable regions, for a set of desired coupler curve characteristics. The description of the desired coupler curve may contain any number of precision points and (or) trajectories. Several problems are solved in this work, including obtaining a representation of the coupler curve corresponding to a set of design parameters containing uncertainties, and synthesizing the appropriate designs for multiple descriptions of desired coupler curves. The results are quite promising and show great potential for using the appropriate design methodology for linkage synthesis.

THE SYNTHESIS OF THE PLANAR LINKAGES WITH SYMMETRICAL CONFIGURATIONS

The mechanisms that employ symmetrical configurations can be found in the steering mechanisms, double open refrigerator, roof boxes, and double open windows, among others. They are useful for some special applications with kinematic symmetry. There have been studies about the linkage synthesis, especially in the research of planar closed chains, from as early as 1960s. However, no study has focused on the symmetry of planar linkages. Thus, the purpose of this paper is to present a methodology to synthesize the configurations of planar linkages. The systematic methodology can be divided into structure synthesis, configuration synthesis and results produced from three major processes. Finally, four suitable results of up to six-bar linkages can be obtained, for example. The four results include one four-bar linkage and three six-bar linkages.