Explore the vast range of titles available.

Classical straight-line mechanisms are one of the most interesting, both from a theoretical and practical point of view. In many cases, those mechanisms frequently produce a nearly straight trajectory rather than one perfectly straight. In compliant form, those mechanisms can produce even better results. Compliant mechanism joints' deformability allows engineers to make further modifications. These modifications may improve the mechanism's ability to follow a straight path even further. This paper will provide an analysis of different hinge sizes, thicknesses, shapes, and overall geometrical characteristics. Their influence on the straightness of the mechanism trajectory will be analyzed and quantified.

Classical straight-line mechanisms are one of the most interesting, both from a theoretical and practical point of view. In many cases, those mechanisms frequently produce a nearly straight trajectory rather than one perfectly straight. In compliant form, those mechanisms can produce even better results. Compliant mechanism joints' deformability allows engineers to make further modifications. These modifications may improve the mechanism's ability to follow a straight path even further. This paper will provide an analysis of different hinge sizes, thicknesses, shapes, and overall geometrical characteristics. Their influence on the straightness of the mechanism trajectory will be analyzed and quantified.

This paper investigates how the electromechanical response of MEMS/NEMS devices changes when the geometrical characteristics of their embedded flexural hinges are modified. The research is dedicated particularly to MEMS/NEMS devices which are actuated by means of rotary comb-drives. The electromechanical behavior of a chosen rotary device is assessed by studying the rotation of the end effector, the motion of the comb-drive mobile fingers, the actuator’s maximum operating voltage, and the stress sustained by the flexure when the flexure’s shape, length, and width change. The results are compared with the behavior of a standard revolute joint. Outcomes demonstrate that a linear flexible beam cannot perfectly replace the revolute joint as it induces a translation that strongly facilitates the pull-in phenomenon and significantly increases the risk of ruptures of the comb-drives. On the other hand, results show how curved beams provide a motion that better resembles the revolute motion, preserving the structural integrity of the device and avoiding the pull-in phenomenon. Finally, results also show that the end effector motion approaches most precisely the revolute motion when a fine tuning of the beam’s length and width is performed.

Innovative designs such as morphing wings and terrain adaptive landing systems are examples of biomimicry and innovations inspired by nature, which are actively being investigated by aerospace designers. Morphing wing designs based on Variable Geometry Truss Manipulators (VGTMs) and articulated helicopter robotic landing gear (RLG) have drawn a great deal of attention from industry. Compliant mechanisms have become increasingly popular due to their advantages over conventional rigid-body systems, and the research team led by the second author at Toronto Metropolitan University (TMU) has set their long-term goal to be exploiting these systems in the above aerospace applications. To gain a deeper insight into the design and optimization of compliant mechanisms and their potential application as alternatives to VGTM and RLG systems, this study conducted a thorough analysis of the design of flexible hinges, and single-, four-, and multi-bar configurations as a part of more complex, flexible mechanisms. The investigation highlighted the flexibility and compliance of mechanisms incorporating circular flexure hinges (CFHs), showcasing their capacity to withstand forces and moments. Despite a discrepancy between the results obtained from previously published Pseudo-Rigid-Body Model (PRBM) equations and FEM-based analyses, the mechanisms exhibited predictable linear behavior and acceptable fatigue testing results, affirming their suitability for diverse applications. While including additional linkages perpendicular to the applied force direction in a compliant mechanism with N vertical linkages led to improved factors of safety, the associated increase in system weight necessitates careful consideration. It is shown herein that, in this case, adding one vertical bar increased the safety factor by 100N percent. The present study also addressed solutions for the precise modeling of CFHs through the derivation of an empirical polynomial torsional stiffness/compliance equation related to geometric dimensions and material properties. The effectiveness of the presented empirical polynomial compliance equation was validated against FEA results, revealing a generally accurate prediction with an average error of 1.74%. It is expected that the present investigation will open new avenues to higher precision in the design of CFHs, ensuring reliability and efficiency in various practical applications, and enhancing the optimization design of compliant mechanisms comprised of such hinges. A specific focus was put on ABS plastic and aluminum alloy 7075, as they are the materials of choice for non-load-bearing and load-bearing structural components, respectively.

Compliant mechanisms are often used in combination with piezoelectric drivers in the design of high-precision linear stages. Numerous hinge designs have been developed due to varying requirements for stiffness and flexibility in different areas of the compliant mechanism frame. Their geometry was traditionally limited mostly to 2D shapes due to limitations of typically used manufacturing processes: electrical discharge machining and stamping. Novel additive manufacturing technologies could allow more complex shapes that could result in better performance. The objective of this paper was to minimize internal losses of the stage caused by unwanted material deformation to maximize efficiency and therefore, the displacement of the linear stage. For this purpose, finite element method simulation was used for the preliminary improvement of geometry, which was afterward confirmed with experimental results. The design of a compliant mechanism with perforated hinges achieved promising results in terms of efficiency improvement.

The use of pressure-actuated cellular structures (PACS) is an effective approach for the application of compliant mechanisms. Analogous to the model in nature, the Venus flytrap, they are made of discrete pressure-activated rows and can be deformed with high stiffness at a high deformation rate. In previous work, a new innovative approach in their integral textile-based manufacturing has been demonstrated based on the weaving technique. In this work, the theoretical and experimental work on the further development of PACS from simple single-row to double-row PACS with antagonistic deformation capability is presented. Supported by experimental investigations, the necessary adaptations in the design of the textile preform and the polymer composite design are presented and concretized. Based on the results of pre-simulations of the deformation capacity of the new PACS, their performance was evaluated, the results of which are presented.

This paper presents a novel origami-based portable deployable canopy system developed using fiber reinforced plastics. A modular system composed of multiple developable strips is proposed to provide a one degree-of-freedom deployment motion from a flat-folded state to a fully deployed state. Each strip is comprised of panels with embedded compliant hinges whose pattern is created in a planar configuration through the laying out of prepreg composite sheets and multi-step curing. The design process of a canopy using this system is demonstrated herein. To capture the complex behaviors and functionality, the design process involves developing different analytical models for each step starting with a simplified model and ending with a refined model. In this case, we defined a parametric design family from rigid origami theory and determined preliminary design parameters through a multi-objective optimization (MOO) scheme in order to balance performance against manufacturing constraints. We then applied geometric nonlinear analyses to assess the kinematic behaviors of the folding actions and also the buckling behavior of the structure in its deployed state. The analyses indicated the need for stability improvement, provided using tension elements. The structure was divided into developable parts that can be manufactured in a planar state. With a total mass of 27 kg, the system can be carried by two or three persons and deployed within a minute.

In order to solve the inherent contradiction of high precision and large working range in the traditional parallel positioning stage, a novel parallel precision stage with large working range based on optimized flexible hinge was studied. Firstly, a new structure parameter Ps was proposed, and its influence on the rotation stiffness was analyzed by comparing the commonly used flexible hinges. The factors that could enlarge the rotation ability were summarized, and the cylindrical flexible hinge with large working range was optimized. Then the cylindrical flexible hinge was used to constructed a novel parallel precision positioning stage, which could realize both of high resolution and large working range by taking use of the step and continuous motion of the piezoelectric actuators. The experiment results show that the resolution of translation is 0.09 μm, and the rotation resolution are 0.8 μrad, 0.9 μrad and 1.0 μrad, respectively. While the working range of the parallel stage could achieve 120 mm for translation, and 6.18°, 6.74° and 6.58°, respectively for each axis of rotation. All of the basic research contents is helpful for further study of the control laws of the compliant parallel mechanism.