CMMI-EPSRC: Enhanced Control Methods for Aerial and Space Vehicles Equipped with Limited Force Actuators

University Of Louisville Research Foundation Inc, Louisville KY

Investigators

Abstract

This research was funded under the NSF Directorate for Engineering - UKRI Engineering and Physical Sciences Research Council Lead Agency Opportunity (ENG-EPSRC), NSF 20-510. This grant will fund research that enables improved design of aerial and space vehicles, such as drones, missiles, rockets, and planetary landers, while ensuring desired flight performance, thereby promoting the progress of science and securing the national defense. Propellers and thrusters used by aerial and space vehicles to control their flight path are limited in the forces they can produce. If the vehicle’s flight control system requests forces that exceed such limits, a consequence may be undesirable flight performance that hinders the mission. To avoid this, engineers presently exploit over-sized thrusters at the expense of increased vehicle weight and cost. In contrast, the control methods developed in this project allow vehicles to be designed with smaller-sized actuators while safeguarding against unstable flight behavior. Applications include Martian landers and ascent vehicles that need to be lightweight in order to reduce costs of production and energy consumption, yet require flight control systems that can compensate for unpredictable environmental forces that otherwise prevent the vehicles from following a desired trajectory. Integrated research, teaching, and outreach activities will be carried out through affiliations with university institutes and external centers that foster multidisciplinary collaboration among engineering and other STEM departments, and through collaborations with scholarly organizations that serve currently underrepresented populations. Unique opportunities for broader impact will result from jointly organized workshops and cross-border mentorship of graduate students by researchers in the United States and the United Kingdom. Engagement with industry and federal research agencies will allow knowledge transfer and possible technology commercialization. This research aims to make fundamental contributions to the application of anti-windup compensation theory to nonlinear systems governed by rigid body dynamics, and to problems of actuator control allocation and actuator quantization that naturally arise in such systems. It achieves this outcome by purposely exploiting the particular nonlinear structure of rigid body dynamics and by enhancing anti-windup compensation design methods for linear systems in order to handle prolonged periods of actuator saturation. The outcomes from the research will yield new realistic control architectures that ensure stability across a wide range of flight conditions, with rigorous performance guarantees also when saturated control signals exist, even when nonlinear dynamics are prevalent. Simulations of high-fidelity lander and ascent vehicle models, as well as experiments with quadcopters, will be used to demonstrate the design methods and validate the theoretical performance predictions. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.