Unified mechanism synthesis method of a planar four-bar linkage for path generation employing a spring-connected arbitrarily sized rectangular block model

Kim, Bum Seok; Yoo, Hong Hee

doi:10.1007/s11044-013-9371-x

Cited by 13 publications

(3 citation statements)

References 7 publications

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“…As explained below, continuous variables cause major issues even though they cannot be avoided for efficient calculations. Besides aforementioned studies, other relevant studies were reported. However, realistic problems appearing in engineering applications could not be solved until recently because of the discrete‐type DOF (degree of freedom) constraint, which is something a rigid body mechanism must satisfy.…”

Section: Introductionmentioning

confidence: 99%

Topology optimization of vehicle rear suspension mechanisms

Kim

Kang

et al. 2017

Numerical Meth Engineering

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As suspensions critically affect the ride and handling performance of vehicles, considerable efforts have been made to improve their design by an optimization method. In this paper, we propose a topology optimization-based method for suspension synthesis by using a 3-dimensional model constructed with nonlinear bars and zero-length springs that discretize the 3-dimensional space between the chassis frame and a vehicle wheel. For optimization, bar cross-sections and spring stiffness values are used as design variables alongside the nodal positions of bar elements as shape optimization variables to simultaneously optimize the topology and shape. To verify the proposed approach, 2 types of design problems were solved: recovering known suspension mechanisms for a given set of wheel trajectories and synthesizing unknown suspension mechanisms that satisfy several design constraints typically used in the automobile industry. Through these examples, possibilities to design new and advanced suspensions by the proposed optimization method are clearly demonstrated. in a reasonable amount of time. Therefore, we hope to set up the topology optimization problem for suspension synthesis by using a numerically efficient gradient-based optimizer.Although there is no study or report that uses the topology optimization method for 3-dimensional vehicle suspension systems, there were earlier studies that dealt with planar linkage mechanisms by topology optimization. To synthesize 3-dimensional suspension systems, a recently proposed energy-based formulation developed for planar mechanisms 5 will be expanded by first reviewing earlier studies that discussed issues and difficulties with rigid body mechanism synthesis using the topology optimization method.Kawamoto 6 proposed a ground model consisting of nonlinear bar elements for the topology optimization-based synthesis of planar linkage mechanisms. An alternative modeling method is to use spring-connected rigid blocks (SBs). 7-9 Whether bar elements or spring-connected rigid blocks are used to make a ground model, mechanism layout determinations, which are discrete in nature, are expressed in terms of continuous design variables since a gradient-based optimizer cannot be used otherwise. As explained below, continuous variables cause major issues even though they cannot be avoided for efficient calculations. Besides aforementioned studies, other relevant studies 10-16 were reported. However, realistic problems appearing in engineering applications could not be solved until recently because of the discrete-type DOF (degree of freedom) constraint, which is something a rigid body mechanism must satisfy. This is not easy to express in the differentiable form when continuous design variables are used to develop a gradient-based topology optimization method. If a mechanism with a single input and a single output is to be synthesized, its DOF should be exactly 1. It is only recently that the DOF issue has been resolved by Kim and Kim 5 for the planar linkage mechanism synthesis by showing th...

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Section: Introductionmentioning

confidence: 99%

Topology optimization of vehicle rear suspension mechanisms

Kim

Kang

et al. 2017

Numerical Meth Engineering

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“…2(a). The SBM was also used to synthesize generalized four-bar mechanisms [27][28][29], but general planar mechanisms were not considered. It is emphasized that while the SBM was used as a reference model for our study, a completely-different model should be developed in order to be able to synthesize mechanisms having general joints at different locations.…”

Section: Introductionmentioning

confidence: 99%

Topology optimization of planar linkage systems involving general joint types

Kang

Kim

2016

Mechanism and Machine Theory

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“…In this paper, a unified synthesis method that can solve planar four-bar linkage body guidance synthesis problems is proposed. Employing the spring-connected block model [15,16] with which path and function generation problems could be solved successfully, an optimization problem is formulated to solve the body guidance problem. The optimization problem is to minimize the difference between the desired and generated orientations of the coupler link while the difference between the desired and generated paths of a coupler point is constrained to be less than a certain value.…”

Section: Introductionmentioning

confidence: 99%