Benjamin Margolis

• Doctor of Philosophy
• Research Assistant at University of California, Davis

Obtaining accurate and timely predictions of the wind through an urban environment is a challenging task, but has wide-ranging implications for the safety and efficiency of autonomous aerial vehicles in future urban airspaces. Prior work relies strongly on global information about the environment, such as a precise map of the city and in-situ wind...

In this paper, we use the calculus of variations to derive a sensitivity analysis for ordinary differential equations with events. This sweeping gradient method (SGM) requires a forward sweep to evaluate the original model and a backwards sweep of the adjoint to compute the sensitivity. The method is applied to canonical optimal control problems wi...

The NASA-funded Pterodactyl Project seeks to advance the current state of the art for atmospheric entry vehicles by developing novel guidance and control technologies for deployable entry vehicles (DEVs). This paper details the efforts of the Pterodactyl team to develop, implement, and evaluate different control hardware effectors on an asymmetric,...

The NASA-funded Pterodactyl project seeks to advance the current state-of-the-art forentry vehicles by developing novel guidance and control technologies for Deployable Entry Vehicles (DEVs). This paper presents the guidance and control design and analysis for a mechanically-deployed DEV with a symmetric aeroshell and aerodynamic control surfaces....

The current state-of-the-art for entry control systems is rooted in heritage entry, descent, and landing (EDL) systems such as Apollo and Mars Science Laboratory. These rigid entry vehicles used Reaction Control System (RCS) thrusters, installed within the backshell, to achieve the desired bank command profile. In recent years, NASA has invested in...

The use of model predictive control (MPC) as a form of inverse dynamics compensation for multi–axis CNC machines, to subdue the inaccuracies incurred by axis inertia and damping, is investigated by both simulation studies and experimental performance analysis using a 3–axis milling machine governed by an open–architecture software controller. The r...

In this paper, we apply a discrete-time Takagi-Sugeno Fuzzy Model (TSFM) based model predictive controller (MPC) to a Martian aerocapture vehicle following an arbitrary trajectory. We compare two baseline controllers: a continuous-time TSFM based parallel distributed controller (PDC) and a finite-horizon linear quadratic regulator (LQR). We evaluat...

In this paper, we present a comparison of three tracking controllers applied to a martian aerocapture vehicle following an arbitrary trajectory: a Takagi-Sugeno Fuzzy Model (TSFM) based discrete-time model predictive controller (MPC), a TSFM based parallel distributed controller (PDC), and a finite-horizon linear quadratic regulator (LQR). The chan...

In this paper, we present a control algorithm for a planetary entry vehicle during an aerocapture maneuver. The proposed algorithm utilizes the model predictive control technique with a Takagi-Sugeno fuzzy model of the vehicle to control the velocity and altitude of the entry vehicle along a specified trajectory using bank angle modulation. A Mars...

Purpose: To review the results of retinal function testing in eyes undergoing panmacular subthreshold diode micropulse laser (SDM) prophylaxis for chronic progressive retinal disease. Setting: A private vitreoretinal subspecialty practice in Ventura, California, USA. Methods: The records of all patients undergoing prophylactic panmacular SDM for...

Purpose: Drug tolerance is the most common cause of treatment failure in neovascular age-related macular degeneration (NAMD). “Low-intensity / high-density” subthreshold diode micropulse laser (SDM) has been reported effective for a number of retinal disorders without adverse effects. It has been proposed that SDM normalizes RPE function. On this b...