Global stabilizing state feedback controller for systems containing double integrator and saturation nonlinearity

[[abstract]]In this paper, we present a Lyapunov function for a system (may contain double integrator) with saturating controller. As usual this Lyapunov function is composed of a quadratic term and an integral term. However, instead of using a positive definite quadratic term, a positive semidefinite quadratic term is used. By using this Lyapunov function we show that for a double integrator system it can be globally stabilized by a saturating linear controller, however, for a triple-integrator system the saturating linear controller does not exist, which agrees with the known result.[[conferencetype]]國內[[conferencedate]]19981212~19981212[[iscallforpapers]]Y[[conferencelocation]]臺中, 臺

[[alternative]]The study on 3 dimensional unstructured grid generation with bowyer scheme

[[abstract]]研究發現，三維空間非結構性格點生成法常遇到如遮蔽、空洞、邊界破壞、區域外格體去除等問題。Advancing Front Algorithrn 發生空洞格體機會很大，而遮蔽卻大部份發生在BowyerAlgorithm 法上。邊界破壞，區域外格體則多數發生在Bowyer Scheme 生成法中。本文嘗試以Bowyer Algori thm 建立不同外形。Bowyer Algori thm 程序簡單，並擁有加點機制。文章中藉建立四種外彤，證明Bowyer Algori thm 在三維空間上的可行性。並提出防止遮蔽、空洞，檢查邊界破壞和區域格體去除的方法。由於非結構性網絡的資料結構需求很大，作者採用C ++ 程式語言作為工具，可有效利用電腦資源及便利程序修改。本文結果證明Bowyer Algori thm 能於三維空間中，對任意外形生成網格。其網格可利用於流場計算、射出成形模擬、心臟血管模擬等。[[abstract]]Unstructured Grid Possess the ability to deal with complex configurations. It has been rapidly developed from the time of 80s and now can be used maturely in solving two dimensional flow field. There are totally four kinds of method:Quadtree Method, Sweepline Method, Advancing Algorithm and Bowyer Algorithm. Both the Advancing Front Algorithm and Bowyer Algorithm has a leading development in three dimensional grid generation, while most . of the rest can only handle a few problems, even specified configurations. In this work, Bowyer Algorithm is chosen for its simplicity and recursive mechanism to develop a general program which generates grid for a number of different configurations successfully. Methods for solving problems of hidden, vacant, boundary breaking and removing invalid volumes, which are located outside of the domain, are discussed.[[conferencetype]]國內[[conferencetkucampus]]淡水校園[[conferencedate]]19951217~19951217[[iscallforpapers]]Y[[conferencelocation]]臺北縣, 臺

[[alternative]]Microburst Simulation via DFI Method

[[abstract]]本研究主題之微風暴為造成許多次飛機失 事之主因。微風暴又名低空風切,產生於雷雨 或小塊雨雲之中,對起飛或降落之飛機將產生 極可怕的影響。由資料顯示出當微風暴接近地 面時,其流場結構頗類似於一暫態之渦旋狀環 流,而本文之目的即在於利用正式直接積分法 模擬出微風暴之流場結構,並以現有之噴射氣 流和環狀渦流模式相互比較。計算結果證實本 方法的確能夠在三千英呎以下的高度模擬出微 風暴之流場結構,並由於計算時間不長,仍然可以使用於飛行模擬器上。[[abstract]]Microbursts, suggested as primary causes of many aircraft fatal crashes, are the subject of this study. A microburst, or low-level intense wind shear, is generated by a thunderstorm or a small rain cloud, and presents hazardous conditions for aircraft during take-off and landing maneuvers. Recently released data show that a microburst resembles a transient vortex ring; the purpose of this research is to construct a vortex ring model for a microburst via the Direct Formal Integration (DFI) method and to compare its computed behavior with that of existing turbulent jet and vortex ring models. In addition to improved understanding of the physical nature of microbursts, this model can also be used for flight simulation and pilot training purposes. Results show that this model is also capable of producing microburst-like flow motion at altitudes below 3000ft, and is still efficient and suitable for flight simulation use.[[sponsorship]]中國航空太空學會; 成功大學; 教育部[[conferencetype]]國內[[conferencedate]]19921126~19921126[[booktype]]紙本[[iscallforpapers]]Y[[conferencelocation]]臺南, 臺

[[alternative]]A research of rotation invariant terrain matching method

[[abstract]]This paper provides an anti-rotation terrain matching method. We used two-dimension digital terrain image to perform terrain matching and locate the correct position of the sensed image. This method can be divided into two steps. First, use a two-dimensional Fast Fourier Transform(2DFFT) to do image matching in frequency domain, and find the proper area that contains the sensed image. Second, return to time domain to do an image matching in the previous chosen area. Process in frequency domain can provide better anti-rotation matching ability. We expect this method can provide flying vehicles a way to correct position error.[[conferencetype]]國內[[conferencedate]]19981212~19981212[[iscallforpapers]]Y[[conferencelocation]]臺中, 臺

Inviscid transonic flow simulation on a full span wing with an accelerated procedure

[[conferencetype]]國內[[conferencedate]]19920515~19920517[[iscallforpapers]]Y[[conferencelocation]]南投縣, 臺

The analysis and synthesis of nonlinear three-dimensional guidance laws using phase plane methods in modified polar coordinate

[[abstract]]In this paper, we presents the general three-dimensional guidance laws. With the aid of the modified polar coordinate, the expression of relative dynamics between target and missile becomes simple, and the constructed guidance law is intuitive and naive. Furthermore, a phase plane method is used to analyze the capture condition of the corresponding guidance law. The result is not restricted to time-invariant navigation constant. For a nonmaneuvering target or a maneuvering target but with known acceleration, it can be seen that only range rate divided by range and the rate of the magnitude of the unit vector along line of sight are related to the intercept condition.[[conferencetype]]國內[[conferencedate]]20000411~20000414[[iscallforpapers]]Y[[conferencelocation]]屏東縣, 臺

[[alternative]]Numerical simulation of transonic inviscid flow about three-dimensional configurations

[[abstract]]A fast, conservative finite difference scheme for the full potential equation has been applied to the three- dimensional transonic flows. This scheme employes the standard approximate factorization ( AF2), upwind bias, temporal damping, and a specific .alpha.-sequence acceleration techniques. To achieve faster and more accurate results, an adaptive grid method using the tension and torsion spring analogies is also being developed. The resulting flow field calculations of half-span, full-span wing, and wing-body combination with different Mach numbers, angles of attack, and sideslip angles show the feasibility and validity of the current method.[[sponsorship]]中國航空太空學會; 成功大學航空太空工程研究所; 行政院國家科學委員會工程科技推展中心[[notice]]20130320格式已修正by陸桂英[[conferencetype]]國內[[conferencedate]]19920515~19920517[[booktype]]紙本[[iscallforpapers]]Y[[conferencelocation]]南投縣, 臺

晴空亂流預測參數之探討

[[abstract]]低空風初或微風暴(Low level wind shear, microburst)代表著氣象因素中危害飛行安全最烈的一個現象; 而晴空亂流(Clear Air Turbulence, CAT)則為氣象因素中影響飛行品質最鉅的另一現象。本文根據以往解決低空風切問題之經驗, 首先以三角函數之特定組合模擬三維晴空亂流風場, 發現與Von karman或Dryden風場相較, 此風場簡單好用又不失其真實性; 再以新創之亂流參數T/sub 1/計算風場之參數值, 此參數代表飛機在三維亂流風場之各方向受力狀態, 除可於飛行模擬器中為飛行訓練之用外, 更可於未來雷達科技更趨成熟時,作為雷達遠距量測晴空亂流並及時閃躲之重要參考資料。[[sponsorship]]中國航空太空學會; 逢甲大學; 經濟部航太工業發展推動小組[[notice]]20130320格式已修正by陸桂英[[conferencetype]]國內[[conferencedate]]19981212~19981212[[booktype]]紙本[[iscallforpapers]]Y[[conferencelocation]]臺中, 臺

Dynamic Output Feedback Compensation for Systems with Independent Amplitude and Rate Saturations

[[abstract]]The positive real lemma provides the basis for constructing linear output feedback dynamic compensators for multi-input plants with independent amplitude saturations. Fixed-structure techniques are used to obtain full- and reduced-order feedback compensators along with a guaranteed domain of attraction. These results are then applied to the problem of rate saturation. By using a feedback-type model, rate saturation is modeled as an amplitude saturation. The closed-loop system with amplitude and rate saturation is then treated as a system with independent "amplitude" saturations.[[conferencetype]]國內[[conferencetkucampus]]淡水校園[[conferencedate]]19951217~19951217[[iscallforpapers]]Y[[conferencelocation]]臺北縣, 臺

Bowyer格點技術於飛行安全上之應用

[[abstract]]本文嘗試以Bowyer's Scheme來作為生成網格點之方法, 並應用於數個不同之飛行安全實例上, 一般而言, 飛行安全上肇事的原因可區分為人為、機械與天候三大因素, 而工程技術上可致力者只有機械與天候二者, 本文嘗試針對陣風、積冰、及襟翼開展等三種狀況, 利用已有之流場格點技術, 做一初步之探討。將首先考量飛機受陣風或亂流時之飛行品質變化, 並考慮機翼積冰現象發生後其對機翼原有性能的影響, 以及在飛機起降時若襟翼無法完全伸展時, 機翼的受力分析。期望研究結果能夠在飛安訓練及飛行員了解物理現象方面, 發揮若干正面的作用。[[conferencetype]]國內[[conferencedate]]19981212~19981212[[iscallforpapers]]Y[[conferencelocation]]臺中, 臺