: The paper continues a series of publications devoted to modern advances in aerodynamic decelerator system technology started recently (Journal of Aircraft, Vol. 38, No. 5, 2001) and addresses the development of a six-degree- of-freedom model of a guided circular parachute. The paper reviews existing circular parachute models and discusses several modeling issues unresolved within the frame of existing approaches or completely ignored so far. These issues include using data obtained in the aerodynamic experiments and computational-fluid-dynamics modeling for both undistorted (uncontrolled) and distorted (controlled) canopy shapes, introducing and computing control derivatives, and providing comparison with the real flight data. The paper provides step-by-step development of the mathematical model of circular parachute that includes the basic equations of motion, analysis and computation of the aerodynamic forces and moments, and investigation with modeling of special modes observed in flight. It then introduces a new application of a two-step aerodynamic parameters identification algorithm that is based on comparison with two types of the air-drop data (uncontrolled set and controlled one). The paper ends with summary of the obtained results and proposes a vital direction for the further elaboration of the developed model.

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Six-Degree-of-Freedom Model of a Controlled Circular Parachute

This paper addresses the development of an autonomous guidance, navigation and control system for a flat solid circular parachute. This effort is a part of the Affordable Guided Airdrop System (AGAS) that integrates a low-cost guidance and control system into fielded cargo air delivery systems. The paper describes the AGAS concept, its architecture and components. It then reviews the literature on circular parachute modeling and introduces a simplified model of a parachute. This model is used to develop and evaluate the performance of a modified bang-bang control system to steer the AGAS along a pre-specified trajectory towards a desired landing point. The synthesis of the optimal control strategy based on Pontryagin's principle of optimality is also presented. The paper is intended to be a summary of the current state of AGAS development. The paper ends with the summary of the future plans in this area.

Performance, Control, and Simulation of the Affordable Guided Airdrop System

Preliminary Consideration of Parameter Identification Analysis from Parachute Aerodynamic Flight Test Data

The work traces a general procedure for the design of a flight simulation tool still representative of the major flight physics of a parachute-payload system along decelerated trajectories. An example of limited complexity simulation models for a payload decelerated by one or more parachutes is given, including details and implementation features usually omitted as the focus of the research in this field is typically on the investigation of mission design issues, rather than addressing general implementation guidelines for the development of a reconfigurable simulation tool. The dynamics of the system are modeled through a simple multibody model that represents the expected behavior of an entry vehicle during the terminal deceleration phase. The simulators are designed according to a comprehensive vision that enforces the simplification of the coupling mechanism between the payload and the parachute, with an adequate level of physical insight still available. The results presented for a realistic case study define the sensitivity of the simulation outputs to the functional complexity of the mathematical model. Far from being an absolute address for the software designer, this paper tries to contribute to the area of interest with some technical considerations and clarifications.

/pdf/parachute-payload-system-flight-dynamics-and-trajectory-r7odkjouhu.pdf

Parachute-Payload System Flight Dynamics and Trajectory Simulation

Reference , A., Flight Mechanics, Vol. 1: "Theory of Flight Paths," Pergamon Press, New York, 1962, Chap. 9, pp. 149-189. solid body inertia tensor ([#]), principal axes, and mass center, there exist an added inertia tensor ([>!]), principal axes, and a center of added mass. Referring to Ibrahim, we find the equivalent external forces and moments exerted on the fluid [Ref. 7, Eqs. (3.46) and (3.47)] are

Added mass and the dynamic stability of parachutes

A computer model of a parachute system based upon a six-degree-of-freedom analysis is described. Its current limitations are discussed and an outline of the analysis and computer program is given. This is followed by a brief description of some comparisons made with real drops and the input data currently considered necessary to simulate the behavior of a real parachute. The paper concludes with a look at possible investigations which could lead to improvements to the model. The program is capable of ready adaptation to cope with a parachute system symmetrical about a plane through its longitudinal axis. The main assumptions are: the payload is rigidly connected; the aerodynamic forces on both canopy and payload aie determined solely by the instantaneous angle of attack of the oncoming airstream; the apparent and included inertias of the system are constants, but are dependent upon the direction of the acceleration. A feature of the model, in addition to those just outlined, is an ability to simulate parachute behavior in a turbulent wind.

Computer Model of a Fully-Deployed Parachute

Journal publisher and ConV2X curator shares vision and insights for scientific communications and scholarly publishing along with market predictions for the digital health and blockchain in healthcare emeging markets and research fields. Biography Tory Cenaj is the Founder and Publisher of Partners in Digital Health (PDH), a forward reaching publishing and communications company. PDH publishes Blockchain in Healthcare Today, the world’s first open access peer reviewed journal disseminating distributed ledger technology research and innovations in healthcare, and Telehealth and Medicine Today, the international open access peer reviewed journal examining the value of telehealth and clinical automation. The portfolio includes the companion Converge2Xcelerate (ConV2X) annual symposium, pitch competition, and PDH Institute. Her leadership experience reflects all facets of healthcare publishing and communications heading a premier MM dollar multispecialty portfolio including digital and international licensing across five continenets. Her industry experience includes leading publication planning, P&amp;L, medical education and clinical trials management. She currently serves as executive advisor to the IEEE SA in telehealth and DCT verticals in addition to her role as publisher. 

Colin Tory

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Computer Model of a Fully-Deployed Parachute

Introduction and Industry Commentary