Extended Kalman Filter on SE(3) for Geometric Control of a Quadrotor UAV

An extended Kalman filter (EKF) is developed on the special Euclidean group, SE(3) for geometric control of a quadrotor UAV. It is obtained by performing an extensive linearization on SE(3) to estimate the state of the quadrotor from noisy measurements. Proposed estimator considers all the coupling effects between rotational and translational dynamics, and it is developed in a coordinate-free fashion. The desirable features of the proposed EKF are illustrated by numerical examples and experimental results for several scenarios. The proposed estimation scheme on SE(3) has been unprecedented and these results can be particularly useful for aggressive maneuvers in GPS denied environments or in situations where parts of onboard sensors fail.Comment: arXiv admin note: text overlap with arXiv:1304.6765, arXiv:1411.298

Attitude Dynamics and Passive Control of a Thrusting, Spinning Spacecraft with Fuel Sloshing

We use Kane’s method to present the equations of motion of a spinning spacecraft with three momentum wheels, a nutation damper, and a spherical pendulum. The spherical pendulum is adopted as a simple mechanical equivalent of fuel sloshing in partially-filled tanks. The proposed model is an extension of the existing model in the literature. We verify and validate our model for two cases: flat spin and a simple reorientation maneuver. Numerical simulations are in agreement with existing results in the literature. Errors in proper orientation of a desired velocity vector of a thrusting, spinning spacecraft are caused by thrust misalignment of various kind. We use a trapezoidal thrust scheme to reduce the error in a spacecraft with fuel sloshing. Equations of motion of the system are derived using Kane’s method accounting time-vary moment of inertia, torque and mass with planar and spherical pendulums models of fuel slosh that are the most accurate mechanical equivalent models available in the literature. Comparison between the Star 48B thrust scheme and proposed trapezoidal thrust scheme are proposed with optimizing the trapezoidal thrust scheme in order to minimize the average velocity pointing error. Simulation results for an existing simple thrusting rigid body model confirm the accuracy of our model

Geometric stabilization of a quadrotor UAV with a payload connected by flexible cable

Abstract — This paper deals with dynamics and control of a quadrotor UAV with a payload that is connected via a flexible cable, which is modeled as a system of serially-connected links. It is shown that a coordinate-free form of equations of motion can be derived for an arbitrary number of links according to Lagrangian mechanics on a manifold. A geometric nonlinear control system is also presented to asymptotically stabilize the position of the quadrotor while aligning the links to the vertical direction. These results will be particularly useful for aggressive load transportation that involves deformation of the cable. The desirable properties are illustrated by a numerical example and a preliminary experimental result. I

Investigation of the Effects of the Reinforcement of Civil Society and Administrative Amendments on Good Governance as well as the Reduction of Administrative Corruption (the Case of the Tax Office of the City of Arak)

The author of the present study has tried to investigate the effects of reinforcement of civil society and administrative amendments on good governance as well as the reduction of administrative corruption. The population of this study is comprised of the entire employees of the tax office of the city of Arak. In terms of purpose, the present research is considered as an applied study while in terms of methods, it is considered as an objective study and hence, for the purpose of the collection of the required research data the author has practiced several library studies in addition to using a questionnaire form that was distributed among 205 employees. The former questionnaire was found to be of sufficient validity and reliability. It is worthy of mentioning that the research hypotheses of the present study have been analyzed through the application of the LISREL software. Results of the study have shown that: 1) reinforcement of the civil society has a positive effect on good governance; 2) reinforcement of the civil society is of positive effects on the reduction of administrative corruption; 3) Administrative amendment has a positive effect on goof governance; 4) administrative amendment has a positive effect on the reduction of administrative corruption; 5) good governance has a positive effect on the reduction of administrative corruption