Beam-based Compliant Mechanisms (CMs) are increasingly studied and implemented in precision engineering. Straight beams with uniform cross section are the basic modules in several design concepts, which can be deemed as standard CMs. Their behavioral analysis can be addressed with a large variety of techniques, including the Euler–Bernoulli beam theory, the Pseudo-Rigid Body (PRB) method, the beam constraint model and the discretization-based methods. This variety is unquestionably reduced when considering nonstandard CMs, namely design problems involving special geometries, such as curve/spline beams, variable section beams, nontrivial shapes and contact pairs. The 3D Finite Element Analysis (FEA) provides accurate results but its high computational cost makes it inappropriate for optimization purposes. This work compares the potentialities of computationally efficient modeling techniques (1D FEA, PRB method and chained-beam constraint model), focusing on their applicability in nonstandard planar problems. The cross-axis flexural pivot is used as a benchmark in this research due to its high configurable behavior and wide range of applications. In parallel, as an attempt to provide an easy-to-use environment for CM analysis and design, a multi-purpose tool comprising Matlab and a set of modern Computer-Aided Design/Engineering packages is presented. The framework can implement different solvers depending on the adopted behavioral models. Summary tables are reported to guide the designers in the selection of the most appropriate technique and software framework. Lastly, efficient design procedures that allow to configure nonstandard beam-based CMs with prescribed behavior are examined with two design examples.

An Overview of Procedures and Tools for Designing Nonstandard Beam-Based Compliant Mechanisms

A pseudo-rigid body model based on finite displacements and strain energy

Design and modelling of an anti-buckling compliant universal joint with a compact configuration

A generalized pseudo-rigid-body PPRR model for both straight and circular beams in compliant mechanisms

In the operations of the banana postharvesting process, the design and development related to the dehanding machine, the cutting and crushing machine of bunch stalks, and the fiber extraction machine of bunch stalks are in the initial stages. In addition, with the development of society and urbanization, the aging populations in hilly and mountainous areas, where bananas are planted, are becoming a more and more serious problem. The basic physical characteristic parameters of banana bunches, banana hands, and bunch stalks are the basis for studying their biomechanical properties and designing and developing the corresponding mechanical equipment. We measured the diameter, thickness of rind, curvature, density, moisture content, diameter of vascular bundle, weight of bunch stalk, and axial distance and circumferential angle of Brazilian and plantain banana hands using experiments and statistical analysis. Through the combination of physical experiments and numerical statistics, we obtained the value range and changing law of the physical characteristic parameters of banana bunches.

https://www.mdpi.com/2077-0472/11/4/362/pdf

Research on the Physical Characteristic Parameters of Banana Bunches for the Design and Development of Postharvesting Machinery and Equipment

A CPRBM-based method for large-deflection analysis of contact-aided compliant mechanisms considering beam-to-beam contacts

At present, there are few reports on the profiling mechanism that can achieve surface envelope profiling along the surface of a shaft whose radius is constantly changing. Existing profiling mechanisms cannot achieve this function. To this end, a novel deployable arc profiling mechanism is presented in this paper. The mechanism can realize centering deployment along the shaft with a changing radius. The radius of the deployable arc can be adapted to the continuous change of shaft radius, and its surface can always maintain the arc shape for surface envelope profiling. The mechanism is mainly composed of compound cams. Each cam contains multiple grooves, and each groove connects to an arc support linkage. The arc support linkage is controlled by the compound motion of cams in different layers. The pitch curve of each groove is designed by applying the method of relative motion and inverse solution and obtained various parameter equations of the mechanism. The feasibility of this mechanism is verified by analysis, experiment, and application test. The results show that the proposed deployable arc profiling mechanism can achieve the design purpose and the profiling accuracy is kept above 96.425%.

https://www.mdpi.com/2073-8994/11/8/958/pdf

Design and Experiment of Symmetrical Shape Deployable Arc Profiling Mechanism Based on Composite Multi-Cam Structure

The invention discloses a variable diameter impacting inserting cutting type banana combing device. The device comprises a soft blade, a hard blade, a cutter disk, a cutter set synchronous control mechanism, a power source and a torsional elastic fixing circular hoop. When the device works, under the driving of the power source, an annular wrapping structure capable of wrapping banana spike stalksis driven by the cutter set synchronous control mechanism to gather together inward or expand outward in the horizontal direction, an artificial or mechanical mode is adopted to move the banana spikestalks in the center downward so that the annular wrapping structure closely wrapping the banana spike stalks can cut banana comb stalks along the banana spike stalks, and stalk removing and combingwhich are conducted on a whole bunch of bananas comb by comb are achieved; the joint effects of torsional deformation of the torsional elastic fixing circular hoop and a deformation mechanism, the size of the annular wrapping structure capable of wrapping the banana spike stalks is adjusted, and the purpose of self-adaption variable diameter combing for the banana spike stalks is achieved. The device has the advantages that the whole structure is light, the device can be moved conveniently, the operation is safe and saves labor and the like, and is applicable to mechanical banana combing.

Variable diameter impacting inserting cutting type banana combing device

The invention discloses an inserting and cutting type banana combing device capable of surrounding banana stems in a self-adaptive manner. The inserting and cutting type banana combing device comprises a machine frame, a power source, a cutter head, a gear set, connecting rods, a plurality of linear guide rails, L-shaped sliding blocks, springs, hard blade mounting frames, hard blades and soft blades, wherein the gear set is arranged between the cutter head and the table board of the machine frame, and consists of a driving gear and a driven gear; the linear guide rails are annularly arrayed on the cutter head; each L-shaped sliding block is mounted on the corresponding linear guide rail in a sliding manner; each connecting rod is arranged between every two linear guide rails; one ends ofthe connecting rods are hinged to the edge of a center hole of the driven gear, and the other end of the corresponding connecting rod is hinged to the horizontal edge of the corresponding L-shaped sliding block; each hard blade mounting frame is connected with the corresponding L-shaped sliding block through bolts; the springs sleeve the bolts; each hard blade is mounted on the corresponding hardblade mounting frame; each soft blade group is riveted to the outer side of the corresponding hard blade; and every two soft blade groups are riveted to form an annular enveloping structure which canenvelope the banana spike rods. The inserting and cutting type banana combing device disclosed by the invention has the advantages of being light and small in integral structure, convenient to move, safe and labor-saving to operate, self-adaptive to the banana spikes and rods and the like.

Inserting and cutting type banana combing device capable of surrounding banana stems in self-adaptive manner

The invention discloses a variable-diameter self-adaptive rotary cutting type banana bunch cutter. The variable-diameter self-adaptive rotary cutting type banana bunch cutter comprises double-edged internal cutting blades, double-edged external cutting blades, an internal annular blade carrier, an external annular blade carrier, connecting parts, two-section connecting link mechanisms and A-shapeddrag link mechanisms, wherein the internal annular blade carrier and the external annular blade carrier have the same center of circle; a plurality of double-edged internal cutting blades are mountedon the internal annular blade carrier and form an internal annular envelope structure; a plurality of double-edged external cutting blades are mounted on the external annular blade carrier and form an external annular envelope structure; the double-edged internal cutting blades and the double-edged external cutting blades are in staggered arrangement; every two double-edged external cutting blades are connected by the connecting parts; the double-edged internal cutting blades are connected with the corresponding connecting parts by pins; the two-section connecting link mechanisms are movablyhinged with the outer sides of the double-edged external cutting blades; two ends of the bottom parts of the A-shaped drag link mechanisms are hinged with the external annular blade carrier; and the top ends of the A-shaped drag link mechanisms are hinged with the hinge parts of two sections of connecting links of the two-section connecting link mechanisms. The variable-diameter self-adaptive rotary cutting type banana bunch cutter has the advantages of compact structure, light mass, convenient moving, safety in operation, labor saving and the like.

Mo Jiasi

Papers

A CPRBM-based method for large-deflection analysis of contact-aided compliant mechanisms considering beam-to-beam contacts

Design and Experiment of Symmetrical Shape Deployable Arc Profiling Mechanism Based on Composite Multi-Cam Structure

Variable diameter impacting inserting cutting type banana combing device

Inserting and cutting type banana combing device capable of surrounding banana stems in self-adaptive manner

Variable-diameter self-adaptive rotary cutting type banana bunch cutter