This paper describes planar motion modeling for an unmanned surface vehicle (USV), including a comparative evaluation of several experimentally identified models over wide range speeds and planing conditions. The identification objective is to determine model that sufficiently rich enable effective model‐based control design trajectory optimization, simple allow parameter identification, general describe variety hullforms actuator configurations. We focus, however, on specific platform:...

This paper is concerned with time-optimal path planning for a constant-speed unmanned aerial vehicle flying at constant altitude in steady uniform winds. The modeled as particle moving air-relative speed and symmetric bounds on turn rate. It known from the necessary conditions optimality that extremal paths comprise only straight segments maximum-rate turns. An essential observation turns correspond to trochoidal segments, observed an Earth-fixed inertial frame. path-planning problem...

This paper presents a comparison of three model-based algorithms to estimate the wind vector from quadrotor motion, based on increasingly refined models. The vehicle motion models are kinematic particle model, dynamic and rigid-body model. These were characterized using results wind-tunnel experiments flight tests. frequency response characteristics each model then examined determine range fluctuations captured with Analysis shows that bandwidth wind-sensing algorithm increases fidelity...

The purpose of this paper is to show that the method controlled Lagrangians and its Hamiltonian counterpart (based on notion passivity) are equivalent under rather general hypotheses. We study particular case simple mechanical control systems (where underlying Lagrangian kinetic minus potential energy) subject controls external forces in some detail. equivalence makes use almost Poisson structures (Poisson brackets may fail satisfy Jacobi identity) side, which a class gyroscopic side.

This paper describes analysis of steady motions for underwater gliders, a type highly efficient vehicle which uses gravity propulsion. Underwater gliders are winged vehicles locomote by modulating their buoyancy and attitude. Several have been developed proven worth as long-distance, long-duration ocean sampling platforms. so because they spend much flight time in stable, motion. Wings-level gliding has well studied, but turning is more subtle. presents an approximate analytical expression...

Because of the relatively high flapping frequency associated with hovering insects and wing micro-air vehicles (FWMAVs), dynamic stability analysis typically involves direct averaging time-periodic dynamics over a cycle. However, application theorem may lead to false conclusions about FWMAVs. Higher-order techniques be needed understand flight analyze its stability. We use second-order five in response high-amplitude, high-frequency, periodic motion. discuss applicability versus for these insects.

This paper describes an underwater glider motion control system intended to enhance locomotive efficiency by reducing the energy expended vehicle guidance. In previous work, authors derived approximate analytical expression for steady turning applying regular perturbation theory a realistic model. The analysis results suggested use of well-known time-optimal path planning procedure developed Dubins car, often-used model wheeled mobile robot. For gliders operating at their most efficient...

In this paper, we present a nonlinear dynamic model for the motion of rigid vehicle in dense fluid flow that comprises steady, nonuniform component and an unsteady, uniform component. developing basic equations, is assumed to be inviscid, but containing initial vorticity; further rotational effects may then incorporated by modifying angular rate used viscous force moment model. The equations capture important flow-related forces moments are absent simpler models. presented terms both...

We present a model-based approach to wind velocity profiling using motion perturbations of multirotor unmanned aircraft system (UAS) in both hovering and steady ascending flight. A state estimation framework was adapted set closed-loop rigid body models identified for an off-the-shelf quadrotor. The quadrotor used were characterized flight conditions ranging between 0 2 m/s. obtained identification algorithms determine model structures estimate parameters. measurement method validated...

This paper provides an overview of flight-test system identification methods applied in the Virginia Tech Nonlinear Systems Laboratory that focus on modeling small, inexpensive, fixed-wing aircraft controlled by a ground-based pilot. The general approach is outlined with details provided facilities, experiment design methods, instrumentation systems, operations, data processing techniques, and model enabling small flight dynamics development. Specific challenges are overcome, including...

High-fidelity yet compact nonlinear flight dynamic models for multirotor aircraft are derived from blade-element and momentum theory use in control, estimation, simulation, performance applications. The aim is to obtain that valid over a wide range of conditions identifiable experimental data. Through first- second-order Taylor series approximations, linear simplified also obtained, which can be more readily used control law estimator design. turn reveal physical principles underlying...

Understanding wind conditions is critical for the NASA Advanced Air Mobility (AAM) mission. The types of aircraft, and region atmosphere they operate in, make them highly susceptible to effects. We demonstrate feasibility using lidar measure dynamics AAM Wind vector measurements from two Doppler lidars dual-Doppler techniques are compared with in situ a ground-based sonic anemometer small uninhabited aircraft systems (sUAS). Both beams intersected directly above were compared. resulting root...

This paper presents a novel extended Kalman filter (EKF)-based nonlinear predictor—the predictor (EKP)—and compares its performance with two linear predictors, the Smith (SP) and (KP). A motivating application is telerobotic operation using predictive display that requires knowledge of robot pose despite time delays at input output. The provides mathematical formulation EKP, as well demonstrates their use for simulated flight small, fixed-wing uncrewed air vehicle. EKP performs comparably to...

Abstract Unmanned aerial vehicles (UAVs) are an important tool to track the long‐distance movement of plant pathogens above crop fields. Here, we describe use a control strategy (coordination via speed modulation) synchronize two autonomous UAVs during aerobiological sampling potato late blight pathogen, Phytophthora infestans . The shared position coordinates wireless mesh network and modulated their speeds so that they were properly phased within orbits. Three coordinated experiments...

This paper describes system identification of a nonlinear flight dynamic model for small, low-cost, fixed-wing unmanned aircraft with limited instrumentation system. Unique challenges include greater sensitivity to atmospheric disturbances and degraded data quality. Methods are presented improve the fidelity identified model, including use vortex lattice method supplement flight-test synthesis from distinct maneuvers. The parameter estimation strategy is based on time-domain formulation...

We present two reduced-dimensional, noncanonical Hamiltonian models for a neutrally buoyant underwater vehicle coupled to an internal moving mass. It is expected that these will be useful in designing nonlinear control laws gliders as well spacecraft, atmospheric re-entry vehicles, and other vehicles which use mass actuators. To illustrate, we investigate stability of steady motion using potential shaping feedback with actuator.