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Article
Publication date: 29 July 2014

Hou Liqiang, Cai Yuanli, Zhang Rongzhi, Li Hengnian and Li Jisheng

A multi-disciplinary robust design optimization method for micro Mars entry probe (no more than 0.8 m in diameter) is proposed. The purpose of this paper is to design a Mars entry…

194

Abstract

Purpose

A multi-disciplinary robust design optimization method for micro Mars entry probe (no more than 0.8 m in diameter) is proposed. The purpose of this paper is to design a Mars entry probe, not only the geometric configuration, but the trajectory and thermal protection system (TPS). In the design optimization, the uncertainties of atmospheric and aerodynamic parameters are taken into account. The probability distribution information of the uncertainties are supposed to be unknown in the design. To ensure accuracy levels, time-consuming numerical models are coupled in the optimization. Multi-fidelity approach is designed for model management to balance the computational cost and accuracy.

Design/methodology/approach

Uncertainties which cannot defined by usual Gaussian probability distribution are modeled with degree of belief, and optimized through with multiple-objective optimization method. The optimization objectives are set to be the thermal performance of the probe TPS and the corresponding belief values. Robust Pareto front is obtained by an improved multi-objective density estimator algorithm. Multi-fidelity management is performed with an Artificial Neural Network (ANN) surrogate model. Analytical model is used first, and then with the improvement of accuracy, rather complex numerical models are activated. ANN updates the database during the optimization, and makes the solutions finally converge to a high-level accuracy.

Findings

The optimization method provides a way for conducting complex design optimization involving multi-discipline and multi-fidelity models. Uncertainty effects are analyzed and optimized through multi-disciplinary robust design. Because of the micro size, and uncertain impacts of aerodynamic and atmospheric parameters, simulation results show the performance trade-off by the uncertainties. Therefore an effective robust design is necessary for micro entry probe, particularly when details of model parameter are not available.

Originality/value

The optimization is performed through a new developed multi-objective density estimator algorithm. Affinity propagation algorithm partitions adaptively the samples by passing and analyzing messages between data points. Local principle component techniques are employed to resample and reproduce new individuals in each cluster. A strategy similar to NSGA-II selects data with better performance, and converges to the Pareto front. Models with different fidelity levels are incorporated in the multi-disciplinary design via ANN surrogate model. Database of aerodynamic coefficients is updated in an online manner. The computational time is greatly reduced while keeping nearly the same accuracy level of high fidelity model.

Details

Engineering Computations, vol. 31 no. 6
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 2 May 2017

Wenjing Zhu, Dexin Zhang, Jihe Wang and Xiaowei Shao

The purpose of this paper is to present a novel high-precision relative navigation method for tight formation-keeping based on thrust on-line identification.

175

Abstract

Purpose

The purpose of this paper is to present a novel high-precision relative navigation method for tight formation-keeping based on thrust on-line identification.

Design/methodology/approach

Considering that thrust acceleration cannot be measured directly, an on-line identification method of thrust acceleration is explored via the estimated acceleration of major space perturbation and the inter-satellite relative states obtained from space-borne acceleration sensors; then, an effective identification model is designed to reconstruct thrust acceleration. Based on the identified thrust acceleration, relative orbit dynamics for tight formation-keeping is established. Further, using global positioning system (GPS) measurement information, a modified extended Kalman filter (EKF) is suggested to obtain the inter-satellite relative position and relative velocity.

Findings

Compared with the normal EKF and the adaptive robust EKF, the proposed modified EKF has better estimation accuracy in radial and along-track directions because of accurate compensation of thrust acceleration. Meanwhile, high-precision relative navigation results depend on high-precision acceleration sensors. Finally, simulation studies on a chief-deputy formation flying control system are performed to verify the effectiveness and superiority of the proposed relative navigation algorithm.

Social implications

This paper provides a reference in solving the problem of high-precision relative navigation in tight formation-keeping application.

Originality/value

This paper proposes a novel on-line identification method for thrust acceleration and shows that thrust identification-based modified EKF is more efficient in relative navigation for tight formation-keeping.

Details

Aircraft Engineering and Aerospace Technology, vol. 89 no. 3
Type: Research Article
ISSN: 1748-8842

Keywords

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Article
Publication date: 16 July 2021

M.N.N. Rodrigo, Srinath Perera, Sepani Senaratne and Xiaohua Jin

Blockchain as an emerging technology has increased the interests within various industries because of its salient features. A potential application of blockchain for embodied…

663

Abstract

Purpose

Blockchain as an emerging technology has increased the interests within various industries because of its salient features. A potential application of blockchain for embodied carbon (EC) estimating is being explored. Though there are several databases/tools to estimate EC, the accuracy of estimates prepared using them is affected due to several limitations. As a solution, a prototype blockchain-based EC (BEC) Estimator for distributed supply chain-based EC estimating has been introduced. The data models and user flow diagram that lead to development of a BEC Estimator are developed and evaluated in this study.

Design/methodology/approach

A case study approach assisted in developing the data models and user flow diagram for the BEC Estimator. A Delphi-based expert forum was used to evaluate and produce the refined data models and user flow diagram.

Findings

The BEC Estimator adopts a waterfall model, a system development lifecycle model, in developing the application. The phases, system analysis and system design, consisting the development of the data models and user flow diagram for the BEC Estimator are discussed.

Originality/value

Estimating EC accurately plays an important role in construction. The BEC Estimator uses the supply chain based embodied carbon estimating method to estimate EC accurately. This paper demonstrates the data models and user flow diagram developed for the BEC Estimator.

Details

Engineering, Construction and Architectural Management, vol. 29 no. 9
Type: Research Article
ISSN: 0969-9988

Keywords

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