Mode transitions in a 6 kW laboratory Hall-effect thruster were induced by varying the magnetic field intensity while holding all other operating parameters constant. Ultrafast imaging, discharge current, and thrust measurements were used to characterize the change in discharge channel current density and thruster performance through mode transitions. The modes are described here as global osci...

This research describes a Hardware in the Loop Simulator (HILS) that was developed to enhance the quality of attitude data received from autopilots. The described system aided in adjusting the contribution of individual IMU sensors and thereby improved the accuracy of IMU data. The HILS system outlined in this research is a gimbaled platform equipped with four stepper motors and two optical sha...

For a fixed-wing Unmanned Aerial Vehicle (UAV) equipped with a gimbaled camera, we consider the problem of tracking a visual target while simultaneously bringing the UAV to orbit on a circular trajectory centered above the target. To achieve this kind of loitering behavior, we propose a feedback control method that is inspired by image-based visual servoing and makes use of a backstepping techn...

Real-time tracking of moving tumors is one of today’s challenges in radiation therapy. This work investigates the tracking performance of VERO, a novel treatment device with gimbaled linear accelerator, especially designed for four dimensional image guided radiotherapy. It is found that the significant impact of organ motion on dose distribution can be overcome by combining a polynomial predict...

For a certain configuration of ablative pulsed plasma thruster, changing the initial energy is an effective way to optimize performance thruster. Different supply methods will not only affect macro discharge characteristics and system but also micro in channel, equivalent parameters circuit, conversion efficiency so on. In this study, characteristics, ablation motion thruster under different ar...

Hall thruster is a kind of plasma optics device, which used mainly in space propulsion. To study the influence magnetic field on performance 5 kW hall thruster, two-dimensional PIC-MCC model was built. The Bohm diffusion modeled by using Brownian motion instead collision method and near-wall conduction secondary electron emission model. When mass flow rate mg/s, like thrust, efficiency discharg...

Historically, sensor noise has been a key factor in the analysis of system performance for formation flying spacecraft. Since most interesting formation missions require coordination between multiple spacecraft, knowledge of the relative states must be as accurate as possible. This knowledge is typically used to design a trajectory to meet specific criteria, such as minimizing fuel use or maint...

A torsional-type thrust stand has been designed and built to test Pulsed Plasma Thrusters (PPTs) in both single shot and repetitive operatingmodes. Using this stand, momentum per pulse was determined strictly as a function of thrust stand deflection, spring stiffness, and natural frequency. No empirical corrections were required. The accuracy of the method was verified using a swinging impact p...