Optimal design of hand-carrying rocker-bogie mechanism for stair climbing

Hee Seung Hong,서태원,김동목,Sun Ho Kim,김종원 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.1

Transporting heavy packages while climbing stairs can be a very difficult or dangerous task. In situations where this task is frequently required such as construction sites, workers would use equipment such as a back rack for convenience, but still it becomes a difficult task as the weight increases. In this paper, we propose a stair climbing hand-carrying cart based on the rocker-bogie mechanism. We conduct an optimal design of the kinematic variables of the rocker-bogie mechanism for stable stair climbing using Taguchi methodology. Fluctuations and a tilted angle during stair climbing are considered to formulate the objective function. Three different shapes of typical stairs are selected as user conditions to determine a robust optimal solution. The results are verified by experiments using a testing set-up of three stair profiles, and the experimental results are compared with simulation. We expect that the results of this research can be applied to stair climbing robot design.

Optimal design of toggle-linkage mechanism for clamping applications

Park, Sumin,Bae, Jangho,Jeon, Youngjae,Chu, Kyungsung,Bak, Jeongae,Seo, TaeWon,Kim, Jongwon Elsevier 2018 Mechanism and machine theory Vol.120 No.-

<P><B>Abstract</B></P> <P>Finger clamp units (FCU) are widely used in industries to clamp flat-shape materials such as steel plates by using a toggle-linkage mechanism. Generally, in toggle-linkage mechanisms, a near singular configuration is used to obtain a high clamping force. Because the high force characteristics in a singular configuration change dramatically for a near singular workspace, the thickness of the plate is limited for a specific toggle-linkage mechanism. In this study, the design of a FCU is optimized such that a single FCU is used for plates with different thicknesses. First, various linkage alternatives are investigated to determine the mechanism that is more useful for a toggle linkage. Second, the design is optimized to ensure a high clamping force in a pre-defined range of plate thickness. Verification experiments are performed based on the simulation results. We expect that the proposed toggle-linkage mechanism can be used for various clamping applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Toggle-link mechanism for a large clamping force in a wide range of motion is proposed. </LI> <LI> Single degree-of-freedom closed-chain mechanism alternatives are analyzed. </LI> <LI> Two modified mechanism alternatives are selected to be a candidate of optimum. </LI> <LI> Optimization problem is defined to guarantee high clamping force in pre-defined range. </LI> <LI> Prototype experiment is performed to verify the optimal configuration and parameters. </LI> </UL> </P>

Mechanical characteristics and experimental research of a flexible rope-sheave hoisting mechanism

Shufeng Tang,Renjie Huang,Guoqing Zhao 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.7

Owing to such advantages as long transmission distances and compact structures, flexible rope-sheave lifting mechanisms are important for applications in disaster relief, emergency treatment, high-altitude operations, and robot transmission. Despite their long research history and wide range of applications, the mechanical properties of the interactions between flexible ropes and sheaves have been investigated by few studies, most of which rely on experience and experimental test results for design. The present study developed a mathematical model for the mechanical characteristics of a hoisting mechanism that was composed of a sheave with gear teeth, pressure wheels, and a flexible rope. The critical value for the hoisting mechanism’s slippage was analyzed, and the parameters that affected the lifting performance, such as the sheave groove angle and gear teeth, were simulated and optimized. The results were consistent with the experimental test data. The optimized rope-sheave lifting mechanism was further applied to the design and development of rope-climbing robots, and its lifting performance was experimentally tested. The research results presented in this paper described the mechanical characteristics of the flexible rope-sheave lifting mechanism, combined the mechanical model with the optimized design, and verified them through experiments;this provided guidance for more precise and quantitative applications of flexible rope-sheaves.

A Novel Region Decision Method with Mesh Adaptive Direct Search Applied to Optimal FEA-Based Design of Interior PM Generator

Dongsu Lee,Byung Kwan Son,Jong-Wook Kim,Sang-Yong Jung 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.4

Optimizing the design of large-scale electric machines based on nonlinear finite element analysis (FEA) requires longer computation time than other applications of FEA, mainly due to the huge size of the machines. This paper addresses a new region decision method (RDM) with mesh adaptive direct search (MADS) for the optimal design of wind generators in order to reduce the computation time. The validity of the proposed algorithm is evaluated using Rastrigin and Goldstein-Price benchmark function. Moreover, the algorithm is employed for the optimal design of a 5.6MW interior permanent magnet synchronous generator to minimize the torque ripple. Additionally, mechanical stress analysis as well as electromagnetic field analysis have been implemented to prevent breakdown caused by large centrifugal forces of the modified design.

Optimal design of micro-nano displacement driving mechanism for obtaining mechanical properties of micro structure

Biao Wang,Yan Huang,Yonghong Wang,Peizheng Yan,Qiaosheng Pan 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.5

The mechanical structures of micro-electro-mechanical systems (MEMS) are composed of different types of microstructures, and their mechanical properties are very important for the realisation and reliability of the system performance. One of the key problems in measuring the mechanical properties is the design and implementation of micro-nano displacement driving mechanisms. This paper describes a mechanism that adopts a two-level loading strategy, fast approach, and precise bending displacement loading structures, and has a theoretical analysis and optimal design based on optimal targets of resistance and displacement. The results show that the relative error is 6.98 % for the fast-approaching structure experiment and its optimal simulation and 4.26 % for the precise bending displacement loading structure (PBLS) experiment and its optimal simulation. The optimised micro-nano displacement loading mechanism can achieve optimal output performance under existing constraints.

Design and dimension optimization of cutter disassembly mechanism for shield tunneling machine

Yi-Min Xia,Mei Yang,Zhiyong Ji,Lianhui Jia,Zixiong Zhou,Dun Wu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.7

This study focuses on configuration and dimension optimization of cutter disassembly mechanism. Firstly, a cutter disassembly mechanism configuration is proposed with four components and simple actions, based on the theory of inventive problem solving (TRIZ) contradiction solutions. Furthermore, a comprehensive dimension optimization strategy was developed, including non-dimensional normalization model, kinematic performance atlases and fuzzy comprehensive evaluation method. Then, the optimal relative dimension of crucial parameters was obtained. Combined with the assembly relationship between components, dimension of all parameters was designed for cutter disassembly mechanism. The locking and disassembling process simulation was provided to illustrate the feasibility of the mechanism. The results show that the angular velocity is very smooth and the locking and disassembling actions are realizable without interference for optimized cutter disassembly mechanism. The effectiveness of the configuration and dimension optimization method is validated.

부스터를 이용한 자유도 초정밀 위치결정 3 기구의 최적설계

한석영(Seog Young Han),이병주(Byung-Ju Yi),김선정(Seon Jung Kim),김종오(Jong O Kim),정구봉(Goo Bong Chung) 한국생산제조학회 2005 한국생산제조학회지 Vol.14 No.6

Ultra-precision positioning systems basically require high natural frequency and sufficient workspace. To cope with this requirement, flexure hinge mechanisms have been proposed. However, previous designs are hard to satisfy the functional requirements of the system due to difficulty in modeling and optimizing process applying an independent axiomatic design. Therefore, this paper proposes a new design and design-order based on semi-coupled axiomatic design. A planar 3 DOF parallel type micro mechanism is chosen as an exemplary device. Based on preliminary kinematic analysis and dynamic modeling of the system, an optimal design has been carried out. To check the effectiveness of the optimal parameters obtained from theoretical approach, simulation is performed by FEM. The simulation result shows that a natural frequency of 200.53㎐ and a workspace of 200㎛ × 200㎛ can be ensured, which is in very close agreement with the specified goal of design.

공리적 설계를 이용한 공간형 3자유도 기구의 최적설계

한석영(Seog Young Han),이병주(Byung-Ju Yi),김종오(Jong O Kim),정구봉(Goo Bong Chung),윤상준(Sang-Jun Yoon) 한국생산제조학회 2005 한국공작기계학회 추계학술대회논문집 Vol.2005 No.-

Ultra-precision positioning systems basically require high natural frequency and sufficient workspace. To cope with this requirement, flexure hinge mechanisms have been proposed. However, previous designs are hard to satisfy the functional requirements of the system due to difficulty in modeling and optimization process applying the independent axiomatic design. Therefore, this paper suggests a new design and design-order based on semi-coupled, axiomatic design. A spatial 3-DOF parallel type micro mechanism is chosen as an exemplary device. Based on preliminary kinematic analysis and dynamic modeling of the system, an optimal design is conducted. To check the effectiveness of the optimal parameters obtained by theoretical approach, simulation is performed by FEM.

Parametric Design Optimization of a Tail Mechanism Based on Tri-Wheels for Curved Spoke-Based Stair-Climbing Robots

JeongPil Shin,YoungHwan Kim,Dong-Yoon Kim,Gil Ho Yoon,TaeWon Seo 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.7

Overcoming stairs is an important requirement for mobile robots. Therefore, many studies have been conducted to develop robots with novel stair-climbing mechanisms. A curved-spoke-based stair-climbing robot has been developed to overcome stairs, but had some limitations during stair climbing, such as damage caused by friction with the edge of the stair and impact during locomotion. In a previous study, several tail mechanisms were suggested to solve these problems, and the tri-wheel tail mechanism showed remarkable performance improvements. However, the previous study used only one step size of 300 ×160 mm2. Therefore, in this study, a robust optimal design of the tri-wheel tail mechanism using the Taguchi method is conducted to achieve outstanding performance improvements even for stairs of various sizes and different climbing speeds as user conditions. The design of simulations of the tri-wheel tail mechanisms are performed via orthogonal arrays using a commercial dynamic simulation software tool. The objective function is to minimize the minimum required friction coefficient for a mobile robot to climb stairs without slip. The performance improvements are verified experimentally using a measurable performance index. Thus, these findings can be used to design stair-climbing mobile robots.

Generalized Modeling Method for Compliant Mechanisms considering Rigid-body Deformations

Y. M. Choi(최영만),H. H. Lim(임현호) Korean Society for Precision Engineering 2021 한국정밀공학회 학술발표대회 논문집 Vol.2021 No.11월

The multi-rigid-body matrix method (MRBMM) is a generalized modeling method for obtaining the displacement, stress, and modal information of a compliant mechanism without performing inner-force analysis. MRBMM discretizes a compliant mechanism into flexible hinges and rigid bodies to implement a mass-spring model. The method designs the multi-body spring mechanism using coordinate transformations in a matrix form. In MRBMM, the deformations of the element assumed to be a rigid body are ignored. In some cases, such as displacement amplification mechanisms, non-negligible deformation occurs even in elements other than the flexible hinge. In this paper, we present a multi-compliant-body matrix-method that considers a rigid body as a compliant element, while retaining the generalized framework of the MRBMM. In the MCBMM, a rigid body in the MRBMM is segmented into a certain number of body nodes and flexure hinges. For bridge type displacement amplification mechanism, MCBMM yields the most accurate amplification ratio among several previous modeling methods. Finally, we confirmed that the MCBMM shows improved accuracy in estimating static and dynamic performances of compliant mechanism through an example of XY positioning mechanism with a double-lever mechanism.