Daniel A. Matz
Bio: Daniel A. Matz is an academic researcher from Georgia Institute of Technology. The author has contributed to research in topics: Performance-based navigation & Landing performance. The author has an hindex of 1, co-authored 2 publications receiving 79 citations.
TL;DR: This assessment has shown that negligible propellant mass fraction benefits are seen for reducing the three-sigma position dispersion at the end of the hypersonic guidance phase (parachute deployment) below approximately 3 km.
Abstract: Landing site selection is a compromise between safety concerns associated with the site’s terrain and scientific interest. Therefore, technologies enabling pinpoint landing performance (sub-100-m accuracies) on the surface of Mars are of interest to increase the number of accessible sites for in situ research, as well as allow placement of vehicles nearby prepositioned assets. A survey of the performance of guidance, navigation, and control technologies that could allow pinpoint landing to occur at Mars was performed. This assessment has shown that negligible propellant mass fraction benefits are seen for reducing the three-sigma position dispersion at the end of the hypersonic guidance phase (parachute deployment) below approximately 3 km. Four different propulsive terminal descent guidancealgorithms were examined. Of these four, a near propellant-optimal analytic guidance law showed promisefortheconceptualdesignofpinpointlandingvehicles.Theexistenceofapropellantoptimumwithregardto theinitiationtimeofthepropulsiveterminaldescentwasshowntoexistforvarious flightconditions.Subsonicguided parachutes were shown to provide marginal performance benefits, due to the timeline associated with descent through the thin Mars atmosphere. This investigation also demonstrates that navigation is a limiting technology for Mars pinpoint landing, with landed performance being largely driven by navigation sensor and map tie accuracy.
••01 Jan 2015
TL;DR: A new algorithm employing simpli ed rotational dynamics and a numeric predictor to minimize a rotational energy metric is proposed, and a Monte Carlo analysis of a drogue failure scenario is used to compare the performance of the algorithms.
Abstract: The Orion Multi-Purpose Crew Vehicle is susceptible to ipping apex forward between drogue parachute release and main parachute in ation. A smart drogue release algorithm is required to select a drogue release condition that will not result in an apex forward main parachute deployment. The baseline algorithm is simple and elegant, but does not perform as well as desired in drogue failure cases. A simple modi cation to the baseline algorithm can improve performance, but can also sometimes fail to identify a good release condition. A new algorithm employing simpli ed rotational dynamics and a numeric predictor to minimize a rotational energy metric is proposed. A Monte Carlo analysis of a drogue failure scenario is used to compare the performance of the algorithms. The numeric predictor prevents more of the cases from ipping apex forward, and also results in an improvement in the capsule attitude at main bag extraction. The sensitivity of the numeric predictor to aerodynamic dispersions, errors in the navigated state, and execution rate is investigated, showing little degradation in performance.
TL;DR: A convexification of the control constraints that is proven to be lossless enables the use of interior point methods of convex optimization to obtain optimal solutions of the original nonconvex optimal control problem.
Abstract: Planetary soft landing is one of the benchmark problems of optimal control theory and is gaining renewed interest due to the increased focus on the exploration of planets in the solar system, such as Mars. The soft landing problem with all relevant constraints can be posed as a finite-horizon optimal control problem with state and control constraints. The real-time generation of fuel-optimal paths to a prescribed location on a planet's surface is a challenging problem due to the constraints on the fuel, the control inputs, and the states. The main difficulty in solving this constrained problem is the existence of nonconvex constraints on the control input, which are due to a nonzero lower bound on the control input magnitude and a nonconvex constraint on its direction. This paper introduces a convexification of the control constraints that is proven to be lossless; i.e., an optimal solution of the soft landing problem can be obtained via solution of the proposed convex relaxation of the problem. The lossless convexification enables the use of interior point methods of convex optimization to obtain optimal solutions of the original nonconvex optimal control problem.
TL;DR: This paper presents a new onboard-implementable, real-time convex optimization-based powered-descent guidance algorithm for planetary pinpoint landing developed for onboard use and flight-tested on a terrestrial rocket with the NASA Jet Propulsion Laboratory and the NASA Flight Opportunities Program in 2013.
Abstract: This paper presents a new onboard-implementable, real-time convex optimization-based powered-descent guidance algorithm for planetary pinpoint landing. Earlier work provided the theoretical basis of convexification, the equivalent representation of the fuel-optimal pinpoint landing trajectory optimization problem with nonconvex control constraints as a convex optimization problem. Once the trajectory optimization problem is convexified, interior-point method algorithms can be used to solve the problem to global optimality. Though having this guarantee of convergence motivated earlier convexification results, there were no real-time interior point method algorithms available for the computation of optimal trajectories on flight computers. This paper presents the first such algorithm developed for onboard use and flight-tested on a terrestrial rocket with the NASA Jet Propulsion Laboratory and the NASA Flight Opportunities Program in 2013. First, earlier convexification results are summarized and the result...
TL;DR: In this article, the problem of powered descent guidance and control for autonomous precision landing for next-generation planetary missions is addressed within the model predictive control framework by representing the dynamics of the rigid body in a uniform gravity field via a piecewise affine system taking advantage of the unit dual-quaternion parameterization.
Abstract: The problem of powered descent guidance and control for autonomous precision landing for next-generation planetary missions is addressed. The precision landing algorithm aims to trace a fuel-optimal trajectory while keeping geometrical constraints such as the line of sight to the target site. The design of an autonomous control algorithm managing such mission scenarios is challenging due to fact that critical geometrical constraints are coupled with the translational and rotational motions of the lander spacecraft, leading to a complex motion-planning problem. This problem is approached within the model predictive control framework by representing the dynamics of the rigid body in a uniform gravity field via a piecewise affine system taking advantage of the unit dual-quaternion parameterization. Such a parameterization in turn enables a six-degree-of-freedom motion planning in a unified framework while also admitting a quadratic cost on the required control commands to minimize propellant consumption. A n...
••19 Sep 2016
TL;DR: In this article, the NRC report provides a systematic and thorough ranking of the future technology needs for NASA, it does not discuss in detail the technical aspects of the prioritized technologies (which clearly lie beyond its scope).
Abstract: In early 2011, NASA’s Office of the Chief Technologist (OCT) released a set of technology roadmaps with the aim of fostering the development of concepts and cross-cutting technologies addressing NASA’s needs for the 2011–2021 decade and beyond. In an attempt to engage the external technical community and enhance the development program in light of scarce resources, NASA reached out to the National Research Council (NRC) to review the program’s objectives and prioritize its list of technologies. In January 2012, the NRC released its report entitled “Restoring NASA's Technological Edge and Paving the Way for a New Era in Space.” While the NRC report provides a systematic and thorough ranking of the future technology needs for NASA, it does not discuss in detail the technical aspects of the prioritized technologies (which clearly lie beyond its scope). This chapter, building upon the NRC report and an earlier assessment of NASA’s needs in terms of guidance, navigation, and control technologies, aims at providing such technical details for a selected number of high-priority technologies in the autonomous systems area. Specifically, this chapter focuses on technology area TA04 “Robotics, Tele-Robotics, and Autonomous Systems” and discusses in some detail the technical aspects and challenges associated with three high-priority TA04 technologies: “Relative Guidance Algorithms,” “Extreme Terrain Mobility,” and “Small Body/Microgravity Mobility.” The result is a unified presentation of key autonomy challenges for next-generation space missions.
TL;DR: In this paper, the authors systematically summarized the past development and current state-of-the-art of Mars entry guidance and control technologies and analyzed the advantages and disadvantages of various existing methods.
Abstract: The Mars atmospheric entry phase plays a vital role in the whole Mars exploration mission-cycle. It largely determines the success of the entire Mars mission. In order to achieve a pin-point Mars landing, advanced entry guidance and control is essential. This paper systematically summarizes the past development and current state-of-art of Mars entry guidance and control technologies. More specifically, the Mars entry process and main technical challenges are first introduced. Second, the guidance and control technologies adopted in the past successful Mars landing mission are reviewed in detail. Next, current state-of-art and recent developments of guidance and control for Mars atmospheric entry are summarized at length. The advantages and disadvantages of the various existing methods are analyzed. Lastly, supposing future Mars pin-point landing missions as the potential project application goals, a more comprehensive outlook and prospect for the next-generation Mars entry guidance and control technologies are described.