A Generalized Performance Sensitivity Synthesis Methodology for Four-Bar Mechanisms

1992 ◽  
Author(s):  
Ming-Yih Lee ◽  
Arthur G. Erdman ◽  
Salaheddine Faik
Keyword(s):  
Solution Space ◽  
Design Solution ◽  
Link Length ◽  
Performance Sensitivity ◽  
Closed Chain ◽  
Synthesis Methodology ◽  
Position Synthesis ◽  
The Relationship ◽  
Accuracy Performance ◽  
Sensitivity Maps

Abstract A generalized accuracy performance synthesis methodology for planar closed chain mechanisms is proposed. The relationship between the sensitivity to variations of link lengths and the location of the moving pivots of four-link mechanisms is investigated for the particular objective of three and four position synthesis. In the three design positions case, sensitivity maps with isosensitivity curves plotted in the design solution space allow the designer to synthesize a planar mechanism with desired sensitivity value or to optimize sensitivity from a set of acceptable design solutions. In the case of four design positions, segments of the Burmester design curves that exhibit specified sensitivity to link length tolerance are identified. A performance sensitivity criterion is used as a convenient and a useful way of discriminating between many possible solutions to a given synthesis problem.

scholarly journals A Smart Wing Rib Structure Suitable for Design for Additive Manufacturing (DfAM) Process

2021 ◽  
pp. 1-21
Author(s):  
Ramona Dogea ◽  
◽  
Xiu T Yan ◽  
Richard Millar ◽  
◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Performance Monitoring ◽  
Equivalent Stress ◽  
Solution Space ◽  
Design Solution ◽  
Smart Devices ◽  
Design For Additive Manufacturing ◽  
Wing Structures ◽  
Rib Structure ◽  
Stress And Deformation

Additive manufacturing has been adopted widely across various industries for producing parts mainly due to their ability to create complex geometries, eliminate material wastage and enable faster production rate, among others. Additive manufacturing has also increased design solution space by enabling exploration of mechatronic solutions for mechanical structures. This includes the integration of smart devices into wing structures to achieve a datadriven predictive maintenance-based system. For this, there is still the need to continuously explore various ways of integrating sensory capability into a mechanical structure during the manufacturing processes to ensure improvement and reliability of aircraft components. The scope of this paper was to analyse different wing rib geometries and the influence of embedding sensory capability via design for additive manufacturing process. In this work, three wing rib geometries with cut-outs and for sensory placement were designed and analysed to estimate their equivalent stress and deformation when such sensory locations are introduced. The results confirm the idea that it is feasible to introduce holding cavities for structural performance monitoring sensors without compromising the structural design requirements. The results also show that deformation and stress are highly dependent on the rib thickness and the insertion of sensory locations

Circuit Rectification for Four Precision Position Synthesis of Stephenson Six-Bar Linkages

1992 ◽  
Author(s):  
John A. Mirth ◽  
Thomas R. Chase
Keyword(s):  
Position Synthesis ◽  
The Relationship ◽  
Final Synthesis

Abstract Circuit rectification ensures that a linkage may reach all precision positions without disassembly. The circuit characteristics of Stephenson six-bar linkages can be established by examining the interaction of the four-bar and five-bar chains within the linkage. Preliminary synthesis of the four-bar chain introduces specific conditions that must be met by the five-bar chain for all of the precision positions to lie on a single circuit. These conditions are based on the relationship between the four-bar coupler curve and the dyads/triads that are generated from the centerpoint curve of the final synthesis step. The travel of the coupler curve between the precision positions is compared with the reach of the final dyad/triad to establish circuit conditions. The circuit conditions are applied to points along the centerpoint curve of the final synthesis step to identify those curve segments which will produce a mechanism with all precision positions on the same circuit.

scholarly journals Macroscopic Fundamental Diagram based Road Network Characteristics Identification and Simulation

2020 ◽  
Vol 165 ◽  
pp. 04051
Author(s):  
Yi Yu ◽  
Liang Wang ◽  
Xianglun Mo ◽  
Yao Yu ◽  
Mei liu
Keyword(s):  
Road Network ◽  
Key Factors ◽  
Link Length ◽  
Fundamental Diagram ◽  
Road Density ◽  
Network Characteristics ◽  
The Road ◽  
Macroscopic Fundamental Diagram ◽  
Flow Equilibrium ◽  
The Relationship

As an inherent property of the road network, macroscopic fundamental diagram (MFD) method can effectively describe the traffic status of the urban roads and identify the relationship among key factors, such as traffic flow and occupancy. Currently, using MFD is easily affected by various network inner factors including topology and road density, so in this paper we propose a method to identify inner characteristic of road network and do a series of comparisons under different scenarios with fixed traffic input circumstance. The differential impact of data collector setting locations are discussed with a aim to reveal the respective location setting suitable for various networks conditions in initial; then road topology and density are designed in road network and simulated MFD performances with flow equilibrium affections. It is shown as the dispersion decreasing of link length or road density of network, the network exhibits better operation efficiency so as to increase the output of link flow and the dissipative ability of the road network. Meanwhile, the equivalent of entrances and exits is proved as another important factor has same impact on MFD.

scholarly journals A Method for Queue Length Estimation in an Urban Street Network Based on Roll Time Occupancy Data

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Dongfang Ma ◽  
Dianhai Wang ◽  
Yiming Bie ◽  
Feng Sun ◽  
Sheng Jin
Keyword(s):  
Queue Length ◽  
Estimation Model ◽  
Link Length ◽  
Urban Street ◽  
City Street ◽  
Lane Width ◽  
Relation Model ◽  
Queue Lengths ◽  
Pass Through ◽  
The Relationship

A method estimating the queue length in city street networks was proposed using the data of roll time occupancy. The key idea of this paper is that when the queue length in front of the queue detector becomes longer, the speeds of the following vehicles to pass through the detector will become smaller, resulting in higher occupancy with constant traffic intensity. Considering the relationship between queue lengths and roll time occupancy affected by many factors, such as link length, lane width, lane number, and bus ratio, twelve different conditions were designed, and the traffic data under different conditions was obtained using VISSIM simulation. Based on the analysis of simulation data, an S-type logistic model was decided to develop for the relationship between queue lengths and roll time occupancy, and the fitting equations were obtained under the twelve simulation situations. The average model for the relationship between queue lengths and roll time occupancy was presented by successive multiple linear regression with the fitting equation parameters and simulation parameters, and the estimation model for queue length was presented through analyzing the equation of the average relation model.

scholarly journals Automated Exploration of Design Solution Space Applying the Generative Design Approach

2019 ◽  
Vol 1 (1) ◽  
pp. 1085-1094 ◽  
Author(s):  
Haibing Li ◽  
Roland Lachmayer
Keyword(s):  
Solution Space ◽  
Complex Problem ◽  
Design Approach ◽  
Design Solution ◽  
Generative Design ◽  
Design Elements ◽  
Design Requirements ◽  
Design Solutions ◽  
Feasible Solutions

AbstractDesign is a complex problem-solving activity that transforms design restrictions and requirements into a set of constraints and explores the feasible solutions to satisfy those constraints. However, design solutions generated by traditional modeling approaches are hardly to deal with such constraints, particularly for the exploration of the possible design solution space to enhance the quality of the design outputs and confront the evolving design requirements. In this regard, the Generative Design Approach (GDA) is considered as an efficient method to explore a large design solution space by transforming the design problem into a configuration problem. Fundamentally, GDA explores and stores all the necessary knowledge through a design skeleton and a set of design elements. Thus, design solution space is easily explored by configuring variable design elements via iterative design processes. Further, the output model is not only a design solution but also a design concept that designers could manipulate to explore unconsidered design configurations. Finally, a crank creation as a running example confirmed that GDA provides concrete aids to enhance the diversity of design solutions.

Solution Region Synthesis Methodology of Spatial 5-SS Linkages for Six Given Positions

2017 ◽  
Vol 9 (4) ◽  
Author(s):  
Jianyou Han ◽  
Guangzhen Cui
Keyword(s):  
Feasible Solution ◽  
Limited Range ◽  
The Other ◽  
Dimensional Synthesis ◽  
Link Length ◽  
End Effector ◽  
Solution Region ◽  
Fixed Solution ◽  
Synthesis Methodology

This paper presents a solution region synthesis methodology to perform the dimensional synthesis of spatial 5-spherical–spherical (SS) linkages for six specified positions of the end-effector. Dimensional synthesis equations for an SS link are formulated. After solving the synthesis equations, the curves of moving and fixed joints can be obtained, and they are called moving and fixed solution curves, respectively. Each point on the curves represents an SS link. Considering the limited range of joints at the first position, we can obtain the feasible solution curves. The link length curves can be obtained based on the feasible solution curves. We determine three SS links by selecting three points meeting the requirements on link length curves. Then, the solution region is built by sorting and adding feasible solution curves and projecting the feasible solution curves on the line. The feasible solution region can be obtained by eliminating defective linkages and linkages that fail to meet the other requirements from the solution region. The validity of the formulas and applicability of the proposed approach is illustrated by example.

Super-Large Gear Measurement Using Laser Tracker and CMM

2014 ◽  
Vol 613 ◽  
pp. 111-117
Author(s):  
Zhao Yao Shi ◽  
Jia Chun Lin ◽  
Chen Guang Pan ◽  
Bai Zhang ◽  
Hu Lin
Keyword(s):  
Full Advantage ◽  
The State ◽  
Laser Tracker ◽  
Measuring Apparatus ◽  
And Topology ◽  
Large Gear ◽  
Manufacturing Accuracy ◽  
Key Techniques ◽  
The Relationship ◽  
Accuracy Performance

As general methods can no longer be used to measure super-large gears, their manufacturing accuracy, performance and quality cant be guaranteed. In this paper, after introducing the characteristics, measuring requirement and the state of arts of inspection of super-large gears, a laser tracker and CMM based measuring technology, proposed by Shi, was presented, and the key techniques were discussed. By taking full advantage of the characteristics of a laser tracker and a coordinate measuring apparatus, the super-large gears positioning problem, which was to determine the relationship between the instrument and workpeice, was solved. Thus, the gears profile, helix, and topology error etc. could be measured. Experiments have been carried out to verify the effectiveness of the method. The results showed that the proposed method could be used to measure super-large gears with the diameters up to 10m.

scholarly journals The Kinematic and Dynamic Modeling and Numerical Calculation of Robots with Complex Mechanisms Based on Lie Group Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-34
Author(s):  
Lu-Han Ma ◽  
Yong-Bo Zhong ◽  
Gong-Dong Wang ◽  
Nan Li
Keyword(s):  
Numerical Calculation ◽  
Lie Group ◽  
Dynamic Models ◽  
Lagrange Equation ◽  
Kinematic Parameter ◽  
Model Complexity ◽  
Calculation Error ◽  
Closed Chain ◽  
Complex Mechanisms ◽  
The Relationship

The kinematic and dynamic models of robots with complex mechanisms such as the closed-chain mechanism and the branch mechanism are often very complex and difficult to be calculated. Aiming at this issue, in this paper, the pose of the component in robots is represented by the Euclidean group and its subgroups with the proposed method. The component’s velocity is derived using the relationship between the Lie group and Lie algebra, and the acceleration and Jacobian matrix are then derived on this basis. The Lagrange equation is expressed by the obtained kinematic parameter expressions. Establishing the model with this method can obtain clear physical meaning and make the expressions uniform and easy to program, which is convenient for computer-aided calculation and parameterization. Calculating by the properties of the Lie group can reduce the calculation and model complexity, especially for calculating the velocity and acceleration, which reduces the calculation error and eases the calculation. Therefore, the proposed modeling and calculation method of kinematics and dynamics of robots is especially suitable for robots with complex mechanisms. As an example, the kinematic and dynamic model of the manipulator developed in our laboratory is established and a working process of it is numerically calculated. Then, the results of the numerical calculation are compared with the results of virtual prototype simulation in ADAMS to verify the correctness.

Analysis and Visualization of the Contact Force Solution Space for Multi-Limbed Mobile Robots With Three Feet Contact

2003 ◽  
Author(s):  
Dennis W. Hong ◽  
Raymond J. Cipra
Keyword(s):  
Contact Force ◽  
Dimensional Space ◽  
Contact Point ◽  
Solution Process ◽  
Solution Space ◽  
Contact Forces ◽  
Static Equilibrium ◽  
Equilibrium Equations ◽  
Force Components ◽  
The Relationship

A new analytical method for determining, describing, and visualizing the solution space for the contact force distribution of multi-limbed robots with three feet in contact with the environment in three-dimensional space is presented. The foot contact forces are first resolved into strategically defined foot contact force components to decouple them for simplifying the solution process, and then the static equilibrium equations are applied to find certain contact force components and the relationship between the others. Using the friction cone equation at each foot contact point and the known contact force components, the problem is transformed into a geometrical one to find the ranges of contact forces and the relationship between them that satisfy the friction constraint. Using geometric properties of the friction cones and by simple manipulation of their conic sections, the whole solution space which satisfies the static equilibrium and friction constraints at each contact point can be found. Two representation schemes, the “force space graph” and the “solution volume representation,” are developed for describing and visualizing the solution space which gives an intuitive visual map of how well the solution space is formed for the given conditions of the system.

Sign in / Sign up

Export Citation Format

Share Document