Experimental and Computational Investigation of Closed Loop Flight Control in the Hawkmoth Manduca Sexta

泰森·海德里克博士将研究动物如何通过有限的一组性能不确定的执行器以及具有固有和可变延迟的感觉系统来实现各种稳定的运动行为。具体地说，鹰蛾Manduca sexta的飞行控制将在封闭的自由飞行环境中进行检查，使用计算和实验方法相结合的方法来分析系统，使用工程控制理论。觅食的鹰蛾在它们采蜜的花的前面盘旋，因此必须跟踪花的位置和方向。鹰蛾取食的花朵也往往在微风的扰动下摆动，甚至在S飞蛾在花边盘旋时产生的向下气流的扰动下摆动。因此，天蛾必须发展出一种有效的跟踪行为，这种行为可以在实验室条件下引发，在实验室条件下，天蛾跟踪机械驱动的人造花的运动。这允许在生物相关的整个生物体行为中对系统输入(花的位置)和输出(飞蛾的位置)进行直接的实验操作和测量。此外，众所周知，花的跟踪是基于光学而不是触觉的，并且光学路径受到50到150毫秒或2到6个翅膀跳动的大延迟的影响。飞行中的方位也部分通过光学路径被感知，并受到同样的延迟的影响。这些延迟可能会支配控制器的功能，以至于神经和感觉系统中的限制需要的阻尼超过了单独考虑的生物力学系统所需的阻尼。这些不同因素的影响将通过扩展先前开发的Manduca sexta飞行的动态模拟来评估；该计算模型将用于评估根据给定蛾S的空气动力学和最大肌肉功率输出的物理可能性而推断的飞行控制传递函数。这些结果将建立一种新的系统，用于检查自由行为动物的闭环控制，并将对寻求将控制理论应用于各种规模的生物系统的研究人员感兴趣。这项拟议的研究产生的更广泛的影响包括让高中生和本科生通过实验室协助的方式接触到动手的、实验的生物生物学方法。这项研究的结果将在派S实验室的网站上公布，在国内和国际会议上发表，并发表在科学期刊上。最后，这项研究的结果将应用于微型飞行器的飞行和控制以及其他生物模拟工程努力。

Dr. Tyson Hedrick will study how animals achieve a variety of stable locomotor behaviors with a limited set of actuators of uncertain performance and a sensory system with inherent and variable delays. Specifically, the flight control of the hawkmoth Manduca sexta will be examined in a closed loop, free flight context using a combination of computational and experimental methods to analyze the system using engineering control theory. Feeding hawkmoths hover in front of the flower from which they draw nectar, and therefore must track the position and orientation of the flower. The flowers from which the hawkmoth feeds also tend to oscillate under the perturbation of a slight breeze or even the downward airflow generated by the moth''s own wings as it hovers near the flower. Thus, the hawkmoth has had to develop an effective tracking behavior, which can be elicited under laboratory conditions where the moth tracks the movements of a mechanically actuated artificial flower. This allows direct experimental manipulation and measurement of both the system input (flower position) and output (moth position) in a biologically relevant whole organism behavior. Furthermore, flower tracking is known to have an optical rather than tactile basis, and optic pathways are subject to large delays of 50 to 150 milliseconds, or 2 to 6 wingbeats. Orientation in flight is also partially sensed via optical pathways and is subject to these same delays. These delays may dominate the function of the controller to the extent that limitations in the neural and sensory systems require damping beyond what would be necessary for the biomechanical system considered separately. The influence of these different factors will be evaluated via extension of a dynamic simulation of the flight of Manduca sexta previously developed; this computational model will be used to evaluate the inferred flight control transfer functions in light of what is physically possible given the moth''s aerodynamics and maximum muscle power output. These results will establish a new system for examining closed loop control in freely behaving animals and will be of interest to researchers seeking to apply control theory to biological systems at a variety of scales. The broader impacts resulting from this proposed research include the exposure of high school and undergraduate students to hands-on, experimental approaches in organismal biology by way of laboratory assistanceships. Results from this research will be made available on the PI''s laboratory web site, presented at national and international conferences, and published in scientific journals. Finally, the results of this research will have applications to the flight and control of micro-air vehicles and other bio-mimentic engineering efforts.