讲座时间：2016年6月16日上午10:00
讲座地点：新主楼E706
讲座题目：Analytical Solutions for the Flight-Direction Angle for Energy-Conserved Planar Spacecraft Motion
报告简介：This seminar will present a fundamental discussion of planar motion of a spacecraft within an arbitrary potential field. The spacecraft will be additionally subject to an external force wherein the applied thrust-acceleration is constrained to remain normal to the velocity vector. The system is thus non-conservative but since the thrust force is non-working, the total energy is a conserved quantity. Under this setting, a major result of fundamental importance will be demonstrated: that the flight direction angle (more precisely, the sine of the angle between the position and velocity vectors) is shown to always satisfy a linear first-order differential equation with variable coefficients that depend upon the underlying potential function. As a consequence, an analytical solution for the flight direction angle can be obtained directly in terms of the spacecraft’s distance from the center of the gravitational field for a significant number of special cases for the potential function. In the case of J2-perturbed spacecraft motion within equatorial orbits, the problem is reduced to that of solving an incomplete elliptic integral. Another important implication of the main result established here is that motion problems subject to velocity-normal thrusting can always be reduced to the study of equivalent single degree-of-freedom conservative systems with an effective potential function. The seminar concludes with various examples of both academic and practical interest including the study of bounded two-body Keplerian orbits and their hodograph interpretation.
Maruthi R. Akella教授简介：Dr. Maruthi Akella is a professor of Aerospace Engineering and Engineering Mechanics at the University of Texas at Austin where he holds the Myron L. Begeman Fellowship in Engineering. He received his PhD in Aerospace Engineering from Texas A&M University and prior to joining the UT Austin faculty, he was a postdoctoral fellow with the Yale University Center for Systems Science. Dr. Akella’s research program encompasses control theoretic investigations of nonlinear and coordinated systems, vision-based sensing for state estimation, and development of integrated human and autonomous multivehicle systems. He is the directing the Controls Lab for Distributed and Uncertain Systems (C-DUS Lab) at UT Austin. Dr. Akella currently serves as Technical Editor for the IEEE Transactions on Aerospace and Electronic Systems (T-AES). He is also an Associate Editor for the Journal of Guidance, Control, and Dynamics (JGCD) and the Journal of the Astronautical Sciences (JAS). For his far-reaching contributions to the field of attitude estimation and control, Dr. Akella was presented the prestigious Mechanics and Control of Flight Award by the American Institute of Aeronautics and Astronautics (AIAA). He also received the Judith A. Resnik Award from the IEEE Aerospace and Electronic Systems Society for his fundamental contributions to the adaptive control of space systems. Dr. Akella is a Fellow of the American Astronautical Society (AAS), an Associate Fellow of the AIAA, and an IEEE Senior Member.
发布人：杜晓婷
