Unsteady shock motion on a NACA0012 aerofoil at low reduced frequencies

Using transonic blowdown windtunnel experiments, the 2D unsteady shock motion on a NACA0012 aerofoil is examined at various frequencies typical for helicopter blades in forward flight. The aerofoil is subjected to freestream velocities oscillating periodically between M = 0.66 and M = 0.77. Unsteady pressure traces and schlieren images are analyzed over a range of low reduced frequencies to provide information on shock location and strength throughout the cycle. Unsteady effects were noticeable even at very low reduced frequencies (down to O(0.01). However, through the range of frequencies investigated, and within experimental error, the unsteady shock location showed no discernible lag compared to the quasi-steady behaviour. On the other hand, significant variations were observed in shock strengths with the upstream running part of the cycle (decreasing Mach number) displaying considerably stronger shocks than during the accelerating part of the cycle. It could be shown that this variation in shock strength is primarily caused by the shock motion modifying the relative shock Mach number. As a result is was possible to use the quasi-steady results to predict the unsteady shock behaviour at the frequencies investigated here (below 0(0.1)).

自适应鲁棒H2控制及其在小型无人直升机航向控制中的应用

提出了一个新的鲁棒控制方法并将其应用到小型无人直升机的航向控制中.给出了直升机的非线性航向动力学模型并进行简化,然后线性化为具有仿射不确定性的线性模型.针对这个线性模型,基于线性矩阵不等式方法提出了具有自适应机制的鲁棒H2反馈控制器.这种设计方法可以降低固定增益控制器所固有的保守性,提高控制效果.数字仿真验证了设计方法的可行性。

基于反馈线性化的无人直升机航向控制

本文着重解决小型无人直升机航向自适应控制问题.通过求非线性函数导数,把原始系统扩展为一个带有伪状态变量的新系统.这种方法不必求解非线性函数的逆,并且降低了计算量.证明了该方法的稳定性.针对实际模型直升机实验平台航向动力学模型,仿真结果表明了该方法的有效性.

基于自调整神经元的无人直升机航向控制方法

直升机航向动力学包含输入非线性、时变参数和主-尾旋翼之间的强耦合,传统的比例积分微分(Proportional integral differential,PID)方法很难达到良好的控制性能。基于以上原因,通过把自调整神经元与滑模控制相结合,提出一种能够解决带有输入非线性的航向自适应控制方法。与常规自适应控制相比,用滑模条件代替误差函数作为目标函数,使控制器在保证闭环稳定性的同时,能够进一步使跟踪误差满足期望精度。证明了该方法的稳定性,针对实际模型直升机试验平台航向动力学模型的仿真结果,以及与传统PID方法的比较都表明了该方法的有效性。

基于主动建模的无人直升机增强LQR控制

为了解决无人直升机控制问题,通过把主动建模与LQR(Linear Quadratic Regulator)控制相结合,提出一种能补偿模型差的控制方法。该方法在悬停状态下,采用简化模型设计LQR控制器,并通过UKF(Un-scented-Kalman-Filter)在线估计简化模型与全状态模型的模型差,使用模型差作为补偿项对LQR控制增强。针对实际直升机动力学模型进行仿真,验证了基于UKF的估计和增强LQR控制的有效性。仿真实验结果证明,基于UKF的主动建模技术能够快速估计状态和参数变化,并且增强LQR控制能够使系统适应模型不确定性。

模型直升机航向自适应保性能控制

提出了一种新的模型直升机航向控制算法。针对具有模型不确定性的直升机航向线性模型,提出了一种具有自适应机制的最优保性能控制器。该控制策略通过引入自适应机制降低固定增益控制器所固有的保守性,并且控制器的反馈增益应用线性矩阵不等式(LMIs)方法解得。理论分析和数字仿真表明所设计的控制器具有良好的鲁棒稳定性能。

小型无人直升机实验平台的设计与实现

高级控制算法对于无人直升机实现高机动性非常重要,但是在实现上也经常受制于鲁棒性和实时性的要求。同时这些控制方法在飞行测试时也会带来高风险。本文介绍了一种自制的安装在机械臂上的直升机作为实验平台去验证控制方法的有效性和可行性,这个平台还能够保证飞行测试的安全性。实验结果显示,能够实现转速跟踪控制以及航向动力学的辨识,并证明平台的有效性。

旋翼飞行机器人故障诊断及容错控制方法研究

无人直升机（Unmanned Helicopter）具有固定翼无人机所不具备的很多优势，它具有垂直起降、空中悬停、协调转弯、前飞、侧飞等多种飞行模态。这种独特的飞行性能决定了它的使用价值：在军用方面，无人直升机既能执行各种非杀伤性任务，又能执行各种软硬杀伤性任务，包括侦察、监视、目标截获、诱饵、攻击、通信中继等；在民用方面，无人直升机在航拍、大气监测、交通监控、资源勘探、电力巡检、森林防火、农业等方面具有广泛的应用前景。但是，直升机自身动力学所固有的高度复杂性和不确定性，导致难以对其实现高性能控制，目前视距范围内遥控仍然是其主要的行为方式，这极大地制约着无人直升机的实际应用。近五年来，将机器人学中的自主行为技术与无人直升机平台相结合，构造全自主型无人直升机系统，即所谓的旋翼飞行机器人（Rotary Wing Flying Robot, RWFR），被认为是一种可行的技术路线；同时，与之相关的自主控制方法也成为移动机器人领域的重要研究方向之一。 自主行为能力包括三个层面的内涵：一是自主、在线的环境理解能力，这里的环境不仅是机器人所处的外部环境，也包括其自身的动力学以及健康状态；二是以环境理解为基础的优化行为自主产生能力；三是控制自身本体实现期望行为的能力。对于旋翼飞行机器人而言，其自身健康状态的自主理解以及与之相关的控制行为产生是至关重要的环节，因为它决定着可靠性。旋翼飞行机器人具有多变量、非线性耦合、柔性结构等多种动力学特性[1]，在飞行过程中会遇到风、发动机振动等多种扰动，其机械部件和控制系统极易出现故障，如果故障不能被有效检测或在有限控制周期内没有被及时处理，旋翼飞行机器人就会因其静不稳定的特点而失去控制，导致机体严重损毁甚至地面人员伤亡。 本论文针对旋翼飞行机器人的自主健康诊断与管理能力开展深入研究，重点研究传感器、执行器、飞机本体故障解耦，各子系统故障的检测、辨识与容错控制，面向在线应用的算法实时性等核心问题，旨在建立具有结构简单、实时性好、针对典型故障可实时进行故障诊断及容错控制的方法体系。论文的具体内容如下： 第1章，对故障诊断及容错控制方法的研究现状进行综述，深入分析并归纳旋翼飞行机器人故障诊断与容错控制中存在的问题和发展方向，引出本文的研究内容和重点。同时，在简要介绍国内外各种旋翼飞行机器人实验平台的基础上，选择一种具有典型性的实验平台进行深入分析，总结了其特点和不足，为研制自己的实验平台系统奠定基础。 第2章，作为论文后续方法研究、仿真及实验验证的基础，首先介绍旋翼飞行机器人的动力学模型，接下来介绍本人参与研制的开放式仿真系统，并着重介绍以作者为主要负责人所设计、研发的40公斤起飞重量级旋翼飞行机器人开放式飞行实验平台—ServoHeli-40。 第3章，以阐述ServoHeli-40旋翼飞行机器人自主飞行控制结构及独立通道控制方法为基础，创新性地提出旋翼飞行机器人容错控制体系结构，并分析该结构中各模块任务及作用。针对传感器和执行器故障之间的耦合问题，提出基于贝叶斯推理的异类故障解耦方法，为独立研究传感器、执行器故障扫清障碍。 第4章，重点研究旋翼飞行机器人传感器故障诊断及容错控制。针对不同故障检测类型和阶段，提出了三种方法。首先针对突变类型的传感器故障采用基于db2的小波变换方法进行检测，对传感器数据进行时频域同时变换，实现实时准确分析；其次应用自适应神经网络方法对故障信号及正常飞行中飞行模态变化进行区分，提高了故障检测的可信性与可靠性；最后以多源传感器信息融合为基础，探索在部分传感器出现故障的情况下提供次优的传感器数据。 第5章，重点研究执行器软性故障的在线估计及控制策略在线重构问题。首先提出旋翼飞行机器人执行器定量软性故障的数学表达方法，深入研究两种自适应UKF方法在执行器软性故障在线估计方面的有效性和可行性；最后，提出一种基于故障参数在线估计的控制策略重构方法。 论文针对所提出的方法，以ServoHeli-40旋翼飞行机器人的实际拟合动力学模型为对象开展了仿真研究，部分内容在ServoHeli-40上进行了实际飞行实验验证。

Non-linear analysis of piezolaminated structures

In the recent years the study of smart structures has attracted significant researchers, due to their potential benefits in a wide range of applications, such as shape control, vibration suppression, noise attenuation and damage detection. The applications in aerospace industry are of great relevance, such as in active control of airplane wings, helicopter blade rotor, space antenna. The use of smart materials, such as piezoelectric materials, in the form of layers or patches embedded and/or surface bonded on laminated composite structures, can provide structures that combine the superior mechanical properties of composite materials and the capability to sense and adapt their static and dynamic response, becoming adaptive structures. The piezoelectric materials have the property of generate electrical charge under mechanical load or deformation, and the reverse, applying an electrical field to the material results in mechanical strain or stresses.

Dorothy Rungeling fonds, 1887-2013, n.d.

Dorothy Rungeling was born in 1911 and raised in Fenwick, Ontario, by her adopted mother, Ethelwyn Wetherald. After graduating high school, she attended Fort Erie business College. She worked briefly in Toronto and then Hamilton, but eventually took a job with Brown Brothers’ Nursery in Pelham to be closer to home. Dorothy pursued many interests, learning to play the violin, saxophone and clarinet. She met her husband Charles at a local dance where she was playing. In 1939, they opened an automobile and farm machinery business in Welland. In their spare time, they were active in skeet and trap shooting, for which Dorothy won many trophies. In the early 1940s, Dorothy developed a passion for horses, training and showing them in addition to teaching riding at the Welland Riding Club, as well as judging at horse shows. By the late 1940s her interest in horses was waning, but she soon after discovered and pursued a new interest: flying. She joined the Welland Flying Club, obtained a flying licence, and in 1949 purchased her first plane. She proceeded to obtain a Commercial Pilot Licence in 1951, an Instructor’s Licence in 1953, and a Senior Commercial Licence in 1954. She participated in many air races in the 1950s, including the All Women’s International Air Races, the Women’s Transcontinental Air Races, and the Canadian Governor-General’s Cup Air Race. Some of the most notable races were the 1954 International Air Race, where Dorothy met with President Batista of Cuba, and the Governor-General’s Cup Air Race, where she won 1st place in 1953 and 1956 (and was the only woman competing). In 1958, she was also the first Canadian woman to solo pilot a helicopter. That same year she obtained her Airline Transport Licence. She also wrote several articles on aviation, contributing to publications such as Canadian Aviation and Air Facts, a U.S. aviation magazine. In addition to these articles, Dorothy authored several books about her life, as well as a selection of poems and articles by Ethelwyn Wetherald. As planes became more expensive, Dorothy spent less time flying, instead pursuing an interest in sailing. She and her husband bought a sailboat and became members of the Niagara-on-the-Lake Sailing Club. In 2003, Dorothy was awarded the Order of Canada for her accomplishments. She also wrote a regular column for the Voice of Pelham in 2012-2013, called A Century in Pelham. Dorothy celebrated her 100th birthday in 2011, and remains an active member of the community.

Article - "Fixed Wing to Whirly Bird"

An article written by Dorothy Rungeling about her experience flying a helicopter for the first time. She is instructed by Bert Ratliff of the Bell Helicopter Corp. in a Bell G2 Trooper.

Commemorative Stamp 2010

A commemorative stamp produced by Canada Post in 2010 in honour of Dorothy Rungeling, "Canada's 1st Woman to Solo a Helicopter".

Estudio de seguimiento de las audiometrías de los años 2009, 2010 y 2011 de los pilotos de las fuerzas militares

La audición es el segundo mecanismo sensorial más importante después de la visión para obtener información durante la operación de una aeronave. Les permite a los pilotos percibir, procesar identificar los sonidos del ambiente que los rodea. Así necesita oír bien tanto en vuelo como en tierra, especialmente entre 500 y 3000 Hz para la recepción del lenguaje hablado y de las señales auditivas. Objetivo: Determinar los cambios progresivos en el tiempo y las frecuencias auditivas que se afectan en las audiometrías de los pilotos militares de las fuerzas militares en los años 2009, 2010 y 2011. Material y Métodos: Se trata de un estudio longitudinal de cohorte en el cual se identificará el comportamiento de las audiometrías de la población de pilotos de las fuerzas militares de Colombia en los años 2009, 2010 y 2011. Se hará una revisión retrospectiva de dichas audiometrías. Para dicho fin se tomó la población de pilotos de fuerzas militares que fueron distribuidos en grupos de pilotos de aeronave de ala fija que corresponden a 47 pilotos y ala rotatoria que son 155. Conclusiones: Se encontró que la frecuencia mas alterada en la población total fue la de 6000 Hz, que en lo pilotos de ala fija las frecuencias más afectadas fueron las de 4000 Hz y la de 6000Hz, la frecuencia más afectada en los pilotos de ala rotatoria fueron las de 4000 Hz, 6000 Hz y 8000 Hz, con lo que se concluye que la exposición en los pilotos afecta las frecuencias altas en las audiometrías. Se observó una relación con el número de horas de vuelo y las alteraciones audiométricas encontrándose una alteración en los pilotos entre 1000 y 4000 horas de vuelo en las frecuencias de 4000 Hz, 6000 Hz y 8000 Hz y una alteración de las todas las frecuencias en aquellos pilotos con más de 5000 horas de vuelo en el año 2009, presentando posterior recuperación en los años posteriores sin poder determinar en este estudio las causas de dicha recuperación. Los pilotos de ala rotatoria presentaron un incremento sostenido en todas las frecuencias en comparación con los pilotos de ala fija.

Controlo populacional do Elefante Africano : a imunocontracepção

A imunocontracepção tem sido proposta como possível ferramenta para controlar populações de elefantes que ultrapassem as capacidades do habitat onde vivem. Até à data a única técnica imunocontraceptiva testada em elefantes selvagens foi a vacina contra a zona pelúcida de elefantes fêmea utilizando zona pelúcida porcina (pZP) numa vacina que induz a formação de anticorpos anti-zona pelúcida e consequente bloqueio do processo de fertilização. A literatura disponível revela que tal vacina tem uma eficácia contraceptiva que varia entre 22% e 100%, pode ser administrada à distância através de um dardo, é segura para animais gestantes, não passa na cadeia alimentar e é reversível, pelo menos a médio prazo. O estudo realizado no âmbito deste trabalho, teve como objectivo avaliar a técnica utilizada para a vacinação com pZP da população de elefantes femêa na Makalali game reserve (Africa do Sul) em relação ao método, tempo, efeitos secundários, e custos envolvidos. Todos os animais foram vacinados apartir de um helicóptero, o processo teve uma duração média por elefante de 2.8 minutos, observou-se efeitos secundários locais em 4 individuos, duas das três manadas evidenciaram alterações comportamentais após a vacinação, e o custo total da operação foi de 3417 dólares americanos.

Patch Scale Nest-Site Selection by Marbled Murrelets (Brachyramphus marmoratus)

The Marbled Murrelet (Brachyramphus marmoratus) is a threatened alcid that nests almost exclusively in old-growth forests along the Pacific coast of North America. Nesting habitat has significant economic importance. Murrelet nests are extremely difficult and costly to find, which adds uncertainty to management and conservation planning. Models based on air photo interpretation of forest cover maps or assessments by low-level helicopter flights are currently used to rank presumed Marbled Murrelet nesting habitat quality in British Columbia. These rankings are assumed to correlate with nest usage and murrelet breeding productivity. Our goal was to find the models that best predict Marbled Murrelet nesting habitat in the ground-accessible portion of the two regions studied. We generated Resource Selection Functions (RSF) using logistic regression models of ground-based forest stand variables gathered at plots around 64 nests, located using radio-telemetry, versus 82 random habitat plots. The RSF scores are proportional to the probability of nests occurring in a forest patch. The best models differed somewhat between the two regions, but include both ground variables at the patch scale (0.2-2.0 ha), such as platform tree density, height and trunk diameter of canopy trees and canopy complexity, and landscape scale variables such as elevation, aspect, and slope. Collecting ground-based habitat selection data would not be cost-effective for widespread use in forestry management; air photo interpretation and low-level aerial surveys are much more efficient methods for ranking habitat suitability on a landscape scale. This study provides one method for ground-truthing the remote methods, an essential step made possible using the numerical RSF scores generated herein.