A variety of sensors and positioning methods have been developed over the years. Most methods rely on active sensors (such as sonars or lasers) which have range and power restrictions, or rely on computationally complex (and often slow) methods such as recovering position from stereo or optical flow. This paper describes a system that can determine a robot’s position and orientation, in all six...

The HAUSAT-2 is a 30kg class nanosatellite which is stabilized by 3-axis active control method. Its main mission objectives are to provide studying the scope of activity and ecology of animals using Animal Tracking System (ATS) and collecting the space information data of mission orbit from Electric Plasma Probe (EPP) as a space science payload. 2-axes sun sensors, 3-axes magnetometer, and star...

This paper discusses the pointing control system for NASA’s Space Infra-Red Telescope Facility (SIRTF). After an introduction to the SIRTF mission and telescope, an overview is given of the pointing control hardware, pointing control architecture, pointing requirements and capability, attitude constraints and commanding, attitude observers and required calibrations.

One of the main control challenges of National Aeronautics and Space Administration’s proposed Asteroid Redirect Mission (ARM) is to stabilize and control the attitude of the spacecraft-asteroid combination in the presence of large uncertainty in the physical model of a captured asteroid. We present a new robust nonlinear tracking control law that guarantees global exponential convergence of th...

The study sought to explain remedial learners’ attitude towards English language using three variables: gender, age and locus of control. Three properly validated instruments were used to collect data on the relevant variables from 385 remedial English learners randomly selected from 5 remedial education centers in Ibadan, Nigeria. Data analysis involved the use of multiple regression to explai...

-This study explores the personality traits, perceived personal control, behavioral biases, culture, and socio-demographics in determining individual equity investor’s risk assumption attitude. The study uses a survey approach to collect responses from small equity investors. A conceptual model is developed and hypotheses are tested through structure equation model (SEM). The result identifies ...

This paper addresses attitude coordination control for spacecraft formation with multiple delays. A distributed angular velocity input law is firstly constructed for attitude synchronization and tracking under multiple communication delays. Introducing virtual auxiliary systems makes it possible to integrate the angular velocity input law with the true true control torque, and asymptotic stabil...

This paper proposes an adaptive sliding backstepping control law for quadcopter attitude control. By employing adaptive elements in the sliding mode control formulation the proposed control law avoids a priori knowledge of the upper bounds on the uncertainty. The controller we propose can be used for systems that are in strict feedback form with matched uncertainties. Numerical simulations show...

This paper examines an optimal spacecraft attitude control problem in the presence of complicated attitude forbidden and mandatary zones. The objective is to design an optimal reorientation trajectory for a rigid body spacecraft under constraints, which is originally formulated as a nonlinear programming problem. The attitude forbidden zones are considered to prevent the light-sensitive instrum...

In this paper, motivated by recent developments of velocity-free spacecraft (SC) attitude control techniques and behavioral-based SC formation control a decentralized control algorithm for attitude coordination of SC formation without angular velocity feedback is presented. Asymptotic stability of the SC formation is guaranteed by using Lyapunov analysis and LaSalle’s theorem. The advantage of ...