Purpose

Reducing fuel consumption of unmanned aerial vehicles (UAVs) during transient operation is a cornerstone to achieve environment-friendly operations. The purpose of this paper is to develop a control scheme that improves the fuel economy of a turbojet in its full operating envelope.

Design/methodology/approach

A novel direct-thrust linear quadratic integral (LQI) approach, comprised by an optimal observer/controller satisfying specified performance parameters, is presented. The thrust estimator, based in a Wiener model, is validated with the experimental data of a micro-turbojet. Model uncertainty is characterized by analyzing variations between the identified model and measured data. The resulting uncertainty range is used to verify closed-loop stability with the circle criterion. The proposed controller provides stable responses with the specified performance in the whole operating range, even with after considering plant nonlinearities. Finally, the direct-thrust LQI is compared with a standard thrust controller to assess fuel economy and performance.

Findings

The direct-thrust LQI approach reduced the fuel consumption by 2.1090% in the most realistic scenario. The controllers were also evaluated using the environmental effect parameter (EEP) and transient-thrust-specific fuel consumption (T-TSFC). These novel metrics are proposed to evaluate the environmental impact during transient-thrust operations. The direct-thrust LQI approach has a more efficient fuel consumption according to these metrics. The results also show that isolating the thrust dynamics within the feedback loop has an important impact in fuel economy. Controllers were also evaluated using the EEP and T-TSFC. These novel metrics are proposed to evaluate the environmental impact during transient-thrust operations. The direct-thrust LQI approach has a more efficient fuel consumption according to these metrics. The results also show that isolating the thrust dynamics within the feedback loop has an important impact in fuel economy.

Originality/value

This study shows the design of an effective direct-thrust control approach that minimizes fuel consumption, ensures stable responses for the full operation range, allows isolating the thrust dynamics when designing the controller and is compatible with classical robustness and performance metrics. Finally, the study shows that a simple controller can reduce the fuel consumption of the turbojet during transient operation in scenarios that approximate realistic operating conditions.

中文翻译：

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全包线油耗最小化的涡轮喷气直推控制方案

目的

降低无人机在瞬态运行期间的油耗是实现环保运行的基石。本文的目的是开发一种控制方案，以提高涡轮喷气发动机在其完整运行范围内的燃油经济性。

设计/方法/方法

提出了一种新颖的直接推力线性二次积分 (LQI) 方法，该方法由满足指定性能参数的最佳观测器/控制器组成。基于维纳模型的推力估计器通过微型涡轮喷气发动机的实验数据进行了验证。模型不确定性的特征在于分析识别模型和测量数据之间的变化。由此产生的不确定性范围用于验证圆标准的闭环稳定性。所提出的控制器在整个操作范围内提供具有指定性能的稳定响应，即使在考虑工厂非线性之后也是如此。最后，将直接推力 LQI 与标准推力控制器进行比较，以评估燃油经济性和性能。

发现

在最现实的情况下，直接推力 LQI 方法将油耗降低了 2.1090%。还使用环境影响参数 (EEP) 和瞬态推力特定燃料消耗 (T-TSFC) 对控制器进行了评估。提出这些新颖的指标来评估瞬态推力操作期间的环境影响。根据这些指标，直接推力 LQI 方法具有更有效的燃料消耗。结果还表明，在反馈回路内隔离推力动力学对燃油经济性有重要影响。还使用 EEP 和 T-TSFC 对控制器进行了评估。提出这些新颖的指标来评估瞬态推力操作期间的环境影响。根据这些指标，直接推力 LQI 方法具有更有效的燃料消耗。

原创性/价值

该研究展示了一种有效的直接推力控制方法的设计，该方法可最大限度地减少燃料消耗，确保在整个操作范围内稳定响应，允许在设计控制器时隔离推力动态，并且与经典的稳健性和性能指标兼容。最后，研究表明，在接近现实运行条件的情况下，一个简单的控制器可以在瞬态运行期间降低涡轮喷气发动机的燃料消耗。