scholarly journals Feasibility-Based Design Model For Road Vertical Alignment

2021 ◽  
Vol 16 (4) ◽  
pp. 270-296
Author(s):  
Hongzhi Yang ◽  
Xuliang Guo ◽  
Zhenfeng Wang ◽  
Shanshan Hu
Keyword(s):  
Intelligent Design ◽  
Multiple Constraints ◽  
Vertical Alignment ◽  
Empirical Estimation ◽  
Design Constraints ◽  
Design Efficiency ◽  
Multi Objective ◽  
Design Specifications ◽  
Objective Uncertainty ◽  
And Control

Road vertical alignment design is a multi-objective design problem that needs to consider multiple constraints. Intelligent design based on optimization algorithms cannot wholly solve problems, such as multi-objective, uncertainty, and constraint dynamics. The article proposes a model of dynamically transforming design constraints into feasible regions as the design develops, to provide decision information before design actions rather than performing constraint evaluation after the design that reduces the empirical estimation. The design actions are divided into new design actions and modifying design actions, and corresponding feasible regions derived from constraints of design specifications and control elevations are established, respectively. Geometrical equations and program algorithms of feasible regions are described in the graphic environment, which is applied to the vertical alignment design to improve the design efficiency and decision-making level.

Integrated Design and Multi-Objective Optimization of a Single Stage Heat-Pump Turbocompressor

2013 ◽  
Author(s):  
J. Schiffmann
Keyword(s):  
Design Optimization ◽  
High Efficiency ◽  
Integrated Design ◽  
Heat Pumps ◽  
Small Scale ◽  
Multi Objective Optimization ◽  
Design Constraints ◽  
Multi Objective ◽  
Wide Range ◽  
Standard Design

Small scale turbomachines in domestic heat pumps reach high efficiency and provide oil-free solutions which improve heat-exchanger performance and offer major advantages in the design of advanced thermodynamic cycles. An appropriate turbocompressor for domestic air based heat pumps requires the ability to operate on a wide range of inlet pressure, pressure ratios and mass flows, confronting the designer with the necessity to compromise between range and efficiency. Further the design of small-scale direct driven turbomachines is a complex and interdisciplinary task. Textbook design procedures propose to split such systems into subcomponents and to design and optimize each element individually. This common procedure, however, tends to neglect the interactions between the different components leading to suboptimal solutions. The authors propose an approach based on the integrated philosophy for designing and optimizing gas bearing supported, direct driven turbocompressors for applications with challenging requirements with regards to operation range and efficiency. Using previously validated reduced order models for the different components an integrated model of the compressor is implemented and the optimum system found via multi-objective optimization. It is shown that compared to standard design procedure the integrated approach yields an increase of the seasonal compressor efficiency of more than 12 points. Further a design optimization based sensitivity analysis allows to investigate the influence of design constraints determined prior to optimization such as impeller surface roughness, rotor material and impeller force. A relaxation of these constrains yields additional room for improvement. Reduced impeller force improves efficiency due to a smaller thrust bearing mainly, whereas a lighter rotor material improves rotordynamic performance. A hydraulically smoother impeller surface improves the overall efficiency considerably by reducing aerodynamic losses. A combination of the relaxation of the 3 design constraints yields an additional improvement of 6 points compared to the original optimization process. The integrated design and optimization procedure implemented in the case of a complex design problem thus clearly shows its advantages compared to traditional design methods by allowing a truly exhaustive search for optimum solutions throughout the complete design space. It can be used for both design optimization and for design analysis.

scholarly journals Multi-Objective Optimization of Integrated Civilian-Military Scheduling of Medical Supplies for Epidemic Prevention and Control

Healthcare ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 126
Author(s):  
Hai-Feng Ling ◽  
Zheng-Lian Su ◽  
Xun-Lin Jiang ◽  
Yu-Jun Zheng
Keyword(s):  
Prevention And Control ◽  
Large Scale ◽  
Medical Services ◽  
The Novel ◽  
Multi Objective ◽  
Medical Supplies ◽  
Problem Instances ◽  
Novel Coronavirus ◽  
And Control ◽  
Minimum Ratio

In a large-scale epidemic, such as the novel coronavirus pneumonia (COVID-19), there is huge demand for a variety of medical supplies, such as medical masks, ventilators, and sickbeds. Resources from civilian medical services are often not sufficient for fully satisfying all of these demands. Resources from military medical services, which are normally reserved for military use, can be an effective supplement to these demands. In this paper, we formulate a problem of integrated civilian-military scheduling of medical supplies for epidemic prevention and control, the aim of which is to simultaneously maximize the overall satisfaction rate of the medical supplies and minimize the total scheduling cost, while keeping a minimum ratio of medical supplies reservation for military use. We propose a multi-objective water wave optimization (WWO) algorithm in order to efficiently solve this problem. Computational results on a set of problem instances constructed based on real COVID-19 data demonstrate the effectiveness of the proposed method.

The Intelligent Design of the Gear Reducer

2012 ◽  
Vol 522 ◽  
pp. 823-827
Author(s):  
Jian Jiang Fang ◽  
Wen Jun Qi
Keyword(s):  
Intelligent Design ◽  
Object Oriented ◽  
Data Access ◽  
Mechanical Transmission ◽  
Design Efficiency ◽  
Integrated Technology ◽  
Gear Drive ◽  
Object Oriented Technology ◽  
Wide Range ◽  
User Friendly

The gear drive is the wide range of applications and is particularly important as a form of mechanical transmission, but the design process requires large amounts of data access and computation. In the paper, computer integrated technology and object-oriented technology is used to research and develop the intelligent design of Straight gear reducer system with user-friendly interactive platform, easy to use, high design efficiency and reliable data.

scholarly journals Modeling and Control for a Multi-Rope Parallel Suspension Lifting System under Spatial Distributed Tensions and Multiple Constraints

Symmetry ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 412 ◽  
Author(s):  
Naige Wang ◽  
Guohua Cao ◽  
Lu Yan ◽  
Lei Wang
Keyword(s):  
Differential Equations ◽  
Direct Method ◽  
Input Saturation ◽  
System Stability ◽  
Unknown Boundary ◽  
Multiple Constraints ◽  
Modeling And Control ◽  
Position Regulation ◽  
Lifting System ◽  
And Control

The modeling and control of the multi-rope parallel suspension lifting system (MPSLS) are investigated in the presence of different and spatial distributed tensions; unknown boundary disturbances; and multiple constraints, including time varying geometric constraint, input saturation, and output constraint. To describe the system dynamics more accurately, the MPSLS is modelled by a set of partial differential equations and ordinary differential equations (PDEs-ODEs) with multiple constraints, which is a nonhomogeneous and coupled PDEs-ODEs, and makes its control more difficult. Adaptive boundary control is a recommended method for position regulation and vibration degradation of the MPSLS, where adaptation laws and a boundary disturbance observer are formulated to handle system uncertainties. The system stability is rigorously proved by using Lyapunov’s direct method, and the position and vibration eventually diminish to a bounded neighborhood of origin. The original PDEs-ODEs are solved by finite difference method, and the multiple constraints problem is processed simultaneously. Finally, the performance of the proposed control is demonstrated by both the results of ADAMS simulation and numerical calculation.

Aeroelastic Vehicle Sensor Placement for Feedback Control Applications Using Gain Stability

2000 ◽  
Author(s):  
Abdul G. Al-Shehabi ◽  
Brett Newman
Keyword(s):  
Flight Control ◽  
Optimization Method ◽  
Stability Criteria ◽  
Control Loop ◽  
Aircraft Structure ◽  
Design Constraints ◽  
Optimal Approach ◽  
And Control ◽  
Vehicle Sensor ◽  
Structural Mode

Abstract Optimal positions for aeroelastic vehicle feedback sensors, which meet design constraints and control requirements, are difficult to determine. This paper introduces a systematic and optimal approach for choosing sensor locations based on gain stability criteria. A steepest descent optimization method with constraints is used to minimize such objective criteria, which are based on the dipole magnitudes for each aeroelastic mode appearing in a traditional Evans diagram for a scalar control loop. Each dipole magnitude term is multiplied by a weight parameter. Rigid-body augmentation characteristics are implicitly accounted for in the type of input-output pairs utilized and in predefined loop compensation structure. Constraints enforcing minimum phase zeros in the transfer function are also considered. A flexible aircraft structure is used as an example to demonstrate this procedure. Results indicate flight control and structural mode control characteristics can be effectively balanced.

scholarly journals Multi-Objective Optimization of Aircraft Taxiing on the Airport Surface with Consideration to Taxiing Conflicts and the Airport Environment

2019 ◽  
Vol 11 (23) ◽  
pp. 6728 ◽  
Author(s):  
Zhang ◽  
Huang ◽  
Liu ◽  
Li
Keyword(s):  
Fuel Consumption ◽  
High Efficiency ◽  
Optimization Method ◽  
Pollutant Emissions ◽  
Multi Objective Optimization ◽  
Optimization Scheme ◽  
Nsga Ii ◽  
Multi Objective ◽  
International Airport ◽  
And Control

High-efficiency taxiing for safe operations is needed by all types of aircraft in busy airports to reduce congestion and lessen fuel consumption and carbon emissions. This task is a challenge in the operation and control of the airport’s surface. Previous studies on the optimization of aircraft taxiing on airport surfaces have rarely integrated waiting constraints on the taxiway into the multi-objective optimization of taxiing time and fuel emissions. Such studies also rarely combine changes to the airport’s environment (such as airport elevation, field pressure, temperature, etc.) with the multi-objective optimization of aircraft surface taxiing. In this study, a multi-objective optimization method for aircraft taxiing on an airport surface based on the airport’s environment and traffic conflicts is proposed. This study aims to achieve a Pareto optimized taxiing scheme in terms of taxiing time, fuel consumption, and pollutant emissions. This research has the following contents: (1) Previous calculations of aircraft taxiing pathways on the airport’s surface have been based on unimpeded aircraft taxiing. Waiting on the taxiway is excluded from the multi-objective optimization of taxiing time and fuel emissions. In this study, the waiting points were selected, and the speed curve was optimized. A multi-objective optimization scheme under aircraft taxiing obstacles was thus established. (2) On this basis, the fuel flow of different aircraft engines was modified with consideration to the aforementioned environmental airport differences, and a multi-objective optimization scheme for aircraft taxiing under different operating environments was also established. (3) A multi-objective optimization of the taxiing time and fuel consumption of different aircraft types was realized by acquiring their parameters and fuel consumption indexes. A case study based on the Shanghai Pudong International Airport was also performed in the present study. The taxiway from the 35R runway to the 551# stand in the Shanghai Pudong International Airport was optimized by the non-dominant sorting genetic algorithm II (NSGA-II). The taxiing time, fuel consumption, and pollutant emissions at this airport were compared with those of the Kunming Changshui International Airport and Lhasa Gonggar International Airport, which have different airport environments. Our research conclusions will provide the operations and control departments of airports a reference to determine optimal taxiing schemes.

Experimental verification of textured mechanical seal designed using multi-objective optimization

2019 ◽  
Vol 71 (6) ◽  
pp. 766-771 ◽  
Author(s):  
Xiuying Wang ◽  
Michael Khonsari ◽  
Siyuan Li ◽  
Qingwen Dai ◽  
Xiaolei Wang
Keyword(s):  
Leakage Rate ◽  
Free Form ◽  
Optimization Approach ◽  
Multi Objective Optimization ◽  
Mechanical Seals ◽  
Content Type ◽  
Multi Objective ◽  
Load Carrying ◽  
And Control ◽  
Good Agreement

Purpose This study aims to simultaneously enhance the load-carrying capacity and control the leakage rate of mechanical seals by optimizing the texture shape. Design/methodology/approach A multi-objective optimization approach is implemented to determine the optimal “free-form” textures and optimal circular dimples. Experiments are conducted to validate the simulation results. Findings The experimental coefficient of friction (COF) and leakage rate are in good agreement with the calculated results. In addition, the optimal “free-form” texture shows a lower COF and a lower leakage in most cases. Originality/value This work provides a method to optimize the surface texture for a better combination performance of mechanical seals.

scholarly journals A Global Iterations Method for Recreating Railway Vertical Alignment Considering Multiple Constraints

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 121199-121211
Author(s):  
Hao Pu ◽  
Lu Zhao ◽  
Wei Li ◽  
Jian Zhang ◽  
Zhenya Zhang ◽  
...  
Keyword(s):  
Multiple Constraints ◽  
Vertical Alignment
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