Design of Compliant Universal Joint With Linear Stiffness

This paper presents a new compliant universal joint using four identical generic sheet flexures (short sheets) and a long wire beam. The compliant joint is compact and in mirror symmetry, and is robust to axial buckling in bi-direction. The compliance matrix of the generic sheet, including a straight sheet and an elliptical-arc-fillet (EAF) sheet, is improved at first. Then a normalization-based analytical model of the universal joint is derived, followed by mobility identification of the joint. The relationships between the straight-sheet joint's compliance and the length, width and thickness of the sheet are analysed quickly using the analytical model. The linear finite element analysis (FEA) is further applied to verify the analytical model for different joints. Given different geometrical parameters of the EAF sheet, their effects on the parasitic motion and the maximum deformation of the joint are elaborated. Nonlinear FEA is used to analyse nonlinearities of the joint consisting of straight sheets and a round wire beam, including the large deformation, load-dependent effect, and axial anti-buckling. Experimental results verify the accuracy of the derived analytical models and confirm the successful design of the proposed universal joint.

The revolute outputs effected by the clearances of joints which are caused by the inaccurate precision of processing and error of assembly are analyzed at first, then in order to illustrate the problem the simulation of a kind of parallel mechanism named 3-PRUR is also done in Pro/E and Adams software. At last a kind of compliant revolute joint called split tube flexural pivots based on the principle of elastic material deformation is raised up to solve the problem above. Its feasibility of replacing the traditional revolute pair is analyzed after compliant revolute joint been designed and simulated in ANSYS software.

This work presents a novel miniature contact-aided compliant joint mechanism that can be integrated into millimeter-sized manual or robotic surgical instruments. The design aims to address the trade-off between notched-tube compliant joints' range of motion and stiffness, while also ensuring a compact form factor. The mechanism is constructed from a nitinol tube with asymmetric cutouts and is actuated in bending by a cable. The innovative feature of this design is the incorporation of a contact aid into the notched-tube topology, which acts to both increase the stiffness of the joint and change the shape that it undertakes during bending. Using finite element modeling (FEM) techniques, we present a sensitivity analysis investigating how the performance of this contact-aided compliant mechanism (CCM) is affected by its geometry, and derive a kinematics and statics model for the joint. The FEM simulations and the kinematic and static models are compared to experimental results. The design and modeling presented in this study can be used to develop new miniature dexterous instruments, with a particular emphasis on applications in minimally invasive neurosurgery.

Compliant joints are widely used in the structural design of 3D-printed continuum robots as their monolithic structure can greatly simplify the assembly process. However, some highly flexible compliant joints, such as the leaf-spring joints, still suffer from unstable rotation centers when interfered by external forces, which greatly reduces the motion stability of the constructed continuum robots. To cope with this problem, we propose a topology-optimization-based method in this paper to achieve efficient structural design of the complaint joints in continuum robots. With our method, the rotation stability of compliant joints can be improved without causing stress concentration problems. Experiments were also carried out to evaluate the bending performance of the 3D-printed continuum robots equipped with optimized compliant joints. Results demonstrated that, compared to continuum robots with the conventional leaf-spring joints, the optimized robots showed much less twisting deformation caused by out-of-plane loads, which exhibited the high rotation stability of the optimized joints. In future work, the proposed method can be further developed to achieve optimization of other mechanical properties of the compliant joints in continuum robots.

Basic needs of food, shelter and employment are currently not being provided by a robust economy that far too often bypasses those most in need. Center City Philadelphia is both vibrant and bleak, and like most cities it is constantly vacillating between progress and regression. Pangburn's Philadelphia Farmhouse is designed for immigrant, migrant and transitory residents, giving them the opportunity to live in a supportive communal environment that grows and harvests crops from the vertical fields within a new city infrastructure. Pangburn's Philadelphia Farmhouse presents a holistic approach to housing that incorporates living and growing into a single structure. It incorporates traditional greenhouse growing techniques as well as Controlled Environment Agriculture. Designed to address homelessness and food insecurity, the Philadelphia Farmhouse reveals a new city infrastructure. The Philadelphia Farmhouse creates a new type of architecture that addresses some of a greatest problems-lack of affordable housing, food insecurity and the underlying unstable employment economy.

The topic of this paper concentrates on robots and their new role in the architectural process from the early stage of conceptualization to the final stage of its materialization.By presenting a theoretical framework and an applied case study, this paper tries to initiate the discussion of redefining the status of the robotic machine in architecture.Besides being a regular tool among other digital fabrication tools, the robot and the ability of the architect to technically manipulate them, bears the potential of further reconnecting and intertwining the process behind design and fabrication.Operational and structural processes are being modified and points of focus shifted.Digital design connected by customized robotic machines to digital fabrication has the capability to result in a new type of architecture.

This research proposes that mass timber panels can not only enable a new type of architecture that is sustainable, but that also sounds better. As mass timber construction often exposes the wood structure, and these panels are carefully constructed in factory settings, these panels have the potential to be built so that the acoustically absorptive, reflective, or sound scattering acoustic properties of surfaces can be integrated into the constructive logic and architectural aesthetic of the building. This paper specifically investigates the potentials of the sound scattering performance of cross laminated timber (CLT) panels. Through design, simulation, and prototyping various surface designs are investigated.

espanolTrabajos de prospeccion arqueologica realizados en la parte alta de los valles de Palpa, en la vertiente occidental de los Andes, nos han permitido identificar y registrar un importante numero de asentamientos pertenecientes a la culturaParacas, de manera especial, aquellos pertenecientes a las epocas Paracas Medio (550 a 350 a.C.) y Paracas Tardio (350 a 200 a.C.), entre los que destacan varios sitios bastante grandes que presentan construcciones de piedra que conforman estructuras arquitectonicas en forma de flor. Se trata de construcciones en donde se pueden distinguir patios hundidos de forma de media luna o de forma circular, alrededor de los cuales se disponen recintos en forma de «D» que presentan pequenas terrazas delante del muro recto.Recientes excavaciones en area realizadas en Cutamalla, uno de los asentamientos mas grandes y mejor conservados de la zona, nos han permitido documentar con detalle este tipo de estructuras arquitectonicas, y conocer sus rasgos formales y constructivos, su filiacion cultural, asi como las actividades que se realizaban en ellas.Todos los datos indican que las estructuras arquitectonicas en forma de flor constituyen un nuevo patron arquitectonico Paracas Tardio, cuya distribucion se limita a una parte de la sierra de Lucanas, Ayacucho, y que, hasta el momento, viene a ser unico en toda la sierra sur del Peru. EnglishDuring our archaeological surveys in the upper reaches of the Palpa valleys, at the western slope of the Andes, we identified and registered a large number of settlements of the Paracas culture, most of them dating to the Middle Paracas(550-350 BC) and Late Paracas (350-200 BC) period. Of special interest are several large sites with stone buildings with circular ground plans, similar to the shape of a flower. The center of these architectural complexes consists of acircular or crescent shaped sunken patio, around which are arranged D-shaped enclosures with small terraces in front of the straight wall.Through our large scale excavations in Cutamalla, one of the largest and best preserved settlements in the area, we were able to document in detail this new type of architecture and to define its formal and constructive features, as well as its cultural affiliation and the activities carried out within the structures.All the data recovered so far indicate that these circular structures have to be considered as a new architectural type of the Late Paracas period. The distribution of this new architectural pattern is limited to a part of the highlands of Lucanas, Ayacucho, and, as far as we know, seems to be unique in the southern highlands of Peru.

The antiferroelectric phase is observed on compounds with a new type of architecture: Chiral non-symmetric dimesogens. In this paper, we briefly report their synthesis. Then, we present a detailed analysis of the mesomorphic behaviour, involving many ways of investigations: DSC measurements and optical microscopy, electrooptic properties, pitch measurements and X-Ray scattering. We show that these compounds display a very rich polymorphism, including SA, SC*α, SC*, SC*FI and SC*A phases.

In recent years Pd(II) and Pt(II) cases have been reported wherein metals in square planar complexes were used as nucleophilic partners to construct supramolecular assemblies with electrophilic molecules like σ-hole and π-hole donors. The formation of such assemblies is based on the nucleophilicity and accessibility of the dz2 orbital (in group-10 elements) in the square-planar complexes. This opens new avenues in inorganic chemistry and crystal engineering as it enriches the current toolbox of noncovalent interactions and supramolecular synthons thus allowing the design of new types of architectures in the solid state. This manuscript reports a comprehensive theoretical study characterizing π-hole⋯dz2[MII] (M = group 10 element) interactions from an energetic point of view. Several computational tools based on the topology of the electron density are used. Examined systems had been identified by considering structures in the Cambridge Structural Database where this interaction was used to construct supramolecular assemblies. Several aromatic rings have been used, varying from π-basic to π-acid rings by adjusting the number of fluorine substituents. Moreover, the influence of metal⋯metal interactions on the nucleophilicity of the dz2 orbital has been studied using MEP surface analysis. The π-hole energies are moderately strong (from -5 to -10 kcal mol-1) and the crucial role of dispersion forces is revealed.

In embedded systems a processor core must be designed with low power consumption, low cost and small silicon area in mind since program code often resides in on-chip ROM. To obtain small code size, not only the amount of instruction-level parallelism can be restricted by instruction sets, but also the encoding cost can be reduced by restricting the access to register files. However, communication among register files has to be supported by hardware, e.g. buses and wires, and compilers. In this paper, we propose a new type of architecture by limiting the encoding range to a subset of registers in a register file on the one hand, and keeping the overlap among different ranges on the other hand in order to support communication between all the functional units. We also propose the annotated conflict graph approach for modeling the range constraints in this architecture, which can be applied in combination with any scheduler. However, to overcome the phase coupling between address range assignment and scheduling in code generation, in this paper the address range constraints are transformed and integrated with the existing timing, resource and register file constraints. Constraint analysis techniques [9] are adapted to prune the search spaces based on those constraints. Results show that we can reduce code size up to 24.58% by applying our technique.

Put me on the map, give my industrial city a second chance, make me the centrefold of the Sunday supplements, the cover of in-flight magazines, the backdrop for fashion shoots, give me an iconic landmark, give me – architectural – shock and awe. Charles Jencks, Iconic Buildings: The Power of Enigma (2004), 18. Introduction Political agencies' recent embrace of what has come to be known as ‘iconic’ architecture can be understood as a continuation of longstanding attempts to mobilize major building projects, first, to materialize wider discourses of major social change, and second, to generate surplus value from urban space. The desire to commission sufficiently persuasive and socially resonant architectural forms with which to attract various forms of mobile capital – especially from the private sector and tourism – while at the same time symbolizing an upward trajectory for a place, has seen iconic architecture incorporated enthusiastically into UK cultural policy strategies. The ‘visually consumable’ (Urry 2002) nature of such attention- grabbing buildings, allied to a hope that iconic forms will help create instantly recognizable ‘brand images’ for places, has led Charles Jencks to claim a renewed function for statement architecture. He has observed that in ‘the last ten years a new type of architecture has emerged. Driven by social forces, the demand for instant fame and economic growth, the expressive landmark has challenged the previous tradition of the architectural monument’ (2004: 7).

This thesis explores the fundamentals of a new class of parallel mechanisms called parallel mechanisms with configurable platforms as well as the design and analysis of parallel robots that are based on those mechanisms. Pure parallel robots are formed by two rigid links, the base and the end-effector, connected in parallel by independent serial chains, called legs. The novel concept behind parallel robots with configurable platforms is that the rigid end-effector is replaced by a closed-loop chain, the configurable platform. Some of the links of this closed-loop chain are attached to the legs so its configuration can be fully controlled from the actuators located on the base. The use of a closed-loop chain instead of a rigid end-effector allows the robot to interact with the environment using multiple contact points on the platform. This results in a robot that can combine motion and grasping capabilities into a structure that provides an inherent high structural stiffness. All the actuators are grounded on the base requiring no additional motor at the end-effector location to provide the grasping. High-speed pick-and-place robots and haptic interfaces are examples of devices that can benefit from this new type of architecture.

After a brief reminder about advantages and problems related to the application of large displacement elastic joints in robotic structures, this paper outlines an approach for quantifying the joint's performance in terms of selective compliance (i.e. capability of providing low stiffness along a single desired direction). Local and global performance indexes are proposed which can be used to discern which joint best suits the application requirements. The approach is validated by comparing two beam-like flexures and two novel compliant joints with non trivial morphology.

Beam flexures are frequently used to design large-range Compliant Parallel Mechanisms (CPMs). But geometric nonlinearities induced by axial forces bring challenges to the design and modeling, especially for multi-degree-of-freedom CPMs. This paper presents a nonlinear modeling approach for the proposed 3-prismatic-prismatic-revolute planar CPM based on the beam constraint model. The load-displacement relations of three flexure joints involved in the CPM are derived. Then the force equilibrium conditions and geometric compatibility equations of the end-effector are combined to build the iterative nonlinear model. By giving different inputs, the nonlinear stiffness model and kinetostatic model are established. Based on the developed models, the characteristics of stiffness and actuation forces for the prescribed workspace are investigated. Finally, finite element analyses and experiments are carried out to validate the developed models, and the main reasons for the experimental errors are discussed. The proposed approach can be extended to the modeling of other CPMs, and the obtained model can be further used to guide the design or optimize geometric parameters.