High alpha feedback control for agile half-loop maneuvers of the F-18 airplane

A nonlinear feedback control law for the F/A-18 airplane that provides time-optimal or agile maneuvering of the half-loop maneuver at high angles of attack is given. The feedback control law was developed using the mathematical approach of singular perturbations, in which the control devices considered were conventional aerodynamic control surfaces and thrusting. The derived nonlinear control law was used to simulate F/A-18 half-loop maneuvers. The simulated results at Mach 0.6 and 0.9 compared well with pilot simulations conducted at NASA

Nonlinear feedback control for high alpha flight

Analytical aerodynamic models are derived from a high alpha 6 DOF wind tunnel model. One detail model requires some interpolation between nonlinear functions of alpha. One analytical model requires no interpolation and as such is a completely continuous model. Flight path optimization is conducted on the basic maneuvers: half-loop, 90 degree pitch-up, and level turn. The optimal control analysis uses the derived analytical model in the equations of motion and is based on both moment and force equations. The maximum principle solution for the half-loop is poststall trajectory performing the half-loop in 13.6 seconds. The agility induced by thrust vectoring capability provided a minimum effect on reducing the maneuver time. By means of thrust vectoring control the 90 degrees pitch-up maneuver can be executed in a small place over a short time interval. The agility capability of thrust vectoring is quite beneficial for pitch-up maneuvers. The level turn results are based currently on only outer layer solutions of singular perturbation. Poststall solutions provide high turn rates but generate higher losses of energy than that of classical sustained solutions

Analytical aerodynamic model of a high alpha research vehicle wind-tunnel model

A 6 DOF analytical aerodynamic model of a high alpha research vehicle is derived. The derivation is based on wind-tunnel model data valid in the altitude-Mach flight envelope centered at 15,000 ft altitude and 0.6 Mach number with Mach range between 0.3 and 0.9. The analytical models of the aerodynamics coefficients are nonlinear functions of alpha with all control variable and other states fixed. Interpolation is required between the parameterized nonlinear functions. The lift and pitching moment coefficients have unsteady flow parts due to the time range of change of angle-of-attack (alpha dot). The analytical models are plotted and compared with their corresponding wind-tunnel data. Piloted simulated maneuvers of the wind-tunnel model are used to evaluate the analytical model. The maneuvers considered are pitch-ups, 360 degree loaded and unloaded rolls, turn reversals, split S's, and level turns. The evaluation finds that (1) the analytical model is a good representation at Mach 0.6, (2) the longitudinal part is good for the Mach range 0.3 to 0.9, and (3) the lateral part is good for Mach numbers between 0.6 and 0.9. The computer simulations show that the storage requirement of the analytical model is about one tenth that of the wind-tunnel model and it runs twice as fast

What Does it Mean to Adopt a Trauma-Informed Approach to Research?: Reflections on a Participatory Project With Young People Seeking Asylum in the UK

Trauma-informed (T-I) approaches to working with vulnerable people have gained popularity in practice but are rarely used in academic research and little is known about the challenges of conducting a T-I approach to participatory research. This paper reflects on our experiences of a participatory peer research project involving unaccompanied young people seeking asylum (16–25 years) during the Covid-19 pandemic. Whilst the project adhered to a robust ethical framework, it became apparent at an early stage in the empirical phase that our methods needed to acknowledge and accommodate the trauma of those involved in the project much more thoughtfully and effectively than our ethical framework suggested. With this in mind, we set about identifying the key elements of a T-I approach to research and how these might add value to research with vulnerable and marginalised populations. Our model of a T-I approach to peer research is framed around five core principles: working reflectively with those with lived experience; contextualising trauma; nurturing trust; showing care; and empowering those involved in and affected by the research

Farmer’s Perspective on the Local Food System and Challenges and Successes of Modern Farming

Moderated panel of local farmers discussing farming in the New South and the local food system

Obtaining Consent in Research involving Children – Understanding the Legal and Ethical Framework

This guidance paper describes the importance of obtaining consent from and on behalf of child participants involved in research. It is Guidance Paper 2 in the series The Ethics of Research Involving Children: Common Questions, Potential Strategies and Useful Guidance. Ethical research considers the international and domestic law, as well as ethical and professional, obligations towards ensuring that participants provide valid consent. Issues around consent are paramount in research ethics applications. The law and ethics of consent are not just about ensuring that the child is fully aware of the implications of his or her involvement in the research and is kept safe (which might necessitate obtaining consent also from adults with parental responsibility); it is equally about ensuring that overly paternalistic approaches to consent are avoided, as such approaches may unintentionally undermine children’s autonomy and prevent children from making decisions and expressing themselves on their own terms. As the ESRC notes in its ethical guidance: “Researchers should consider the ethics implications of silencing and excluding children from research.” Beazley et al. (2009: 370) refer to this as children’s right to be ‘properly researched’ which ‘translates into: children being participants in research, using methods that make it easy for them to express their opinions, views and experiences and being protected from harm.

Confidentiality, Privacy and the Protection of Children’s Data

This guidance paper discusses issues of confidentiality, privacy and data protection in relation to the collection of information from or about children for research. It is Guidance Paper 6 in the series The Ethics of Research Involving Children: Common Questions, Potential Strategies and Useful Guidance