A survey on fractional order control techniques for unmanned aerial and ground vehicles

In recent years, numerous applications of science and engineering for modeling and control of unmanned aerial vehicles (UAVs) and unmanned ground vehicles (UGVs) systems based on fractional calculus have been realized. The extra fractional order derivative terms allow to optimizing the performance of the systems. The review presented in this paper focuses on the control problems of the UAVs and UGVs that have been addressed by the fractional order techniques over the last decade

Introducing PHAEDRA: a new spectral code for simulations of relativistic magnetospheres

We describe a new scheme for evolving the equations of force-free electrodynamics, the vanishing-inertia limit of magnetohydrodynamics. This pseudospectral code uses global orthogonal basis function expansions to take accurate spatial derivatives, allowing the use of an unstaggered mesh and the complete force-free current density. The method has low numerical dissipation and diffusion outside of singular current sheets. We present a range of one- and two-dimensional tests, and demonstrate convergence to both smooth and discontinuous analytic solutions. As a first application, we revisit the aligned rotator problem, obtaining a steady solution with resistivity localised in the equatorial current sheet outside the light cylinder.Comment: 23 pages, 18 figures, accepted for publication in MNRA

Regenerating the academic workforce: the careers, intentions and motivations of higher degree research students in Australia

Abstract The main findings of this report are based on the outcomes from the National Research Student Survey (NRSS) conducted in June 2010 across 38 of the 39 universities in Australia. In total 11,710 Higher Degree by Research students (those enrolled in PhD and masters by research degrees, also referred to simply as ‘research students’ in this report) responded to the NRSS, providing a 25.5 per cent response rate across the country. These response numbers represent the largest collection of survey responses from research students ever undertaken in Australia. The report primarily explores the career intentions and motivations of these students. It provides particular emphasis on the interests of Higher Degree by Research (HDR) students (referred to in this report as ‘research students’) in following an academic career on completion of their degree and the support they have received in terms of preparation for university teaching during their candidature. In the context of growing student enrolments and the large numbers of predicted retirements associated with an ageing academic workforce there is a need to examine the career intentions of research students. This report explores the extent to which the current cohort of research students may be a source of replenishment for the academic profession in the context of an ageing academic workforce. It is important to remember that the traditional notion of an academic being someone who has made a linear transition from school to university, to a HDR and on to academia is outdated. Research students come to the HDR from a diverse variety of professional backgrounds and have equally diverse aspirations for their careers after gaining their qualification. Some research students m y already be working in universities in an academic capacity. Many intend to use their research degree as a springboard to a career outside of the university sector. Others undertake a research degree out of interest in the subject matter and simply for the pleasure of studying at an advanced level. Nevertheless, those research students who aspire to an academic career do represent an important source of future academics. The findings of this report raise a number of crucial issues relating to the research degree in Australian universities, the career aspirations of research students and potential issues for the future of the academic workforce over the coming decade. Recommended Citation Edwards, Daniel; Bexley, Emmaline; and Richardson, Sarah, "Regenerating the academic workforce: the careers, intentions and motivations of higher degree research students in Australia: findings of the National Research Student Survey (NRSS)" (2011). http://research.acer.edu.au/higher_education/2

State feedback based fractional order control scheme for linear servo cart system

Fractional order control schemes are being actively investigated for various systems. Fractional order concept is incorporated in integral (I), proportional integral (PI), proportional derivative (PD) or proportional integral derivative (PID) controller to investigate the performance of different state variables of the system. These techniques are often used for the purpose of technology transfer but very scanty research has so far been conducted using state space approach. The current investigation is initiated to observe the effect of fractional order controller using state space approach for the system's performance while tracking the position and regulating the speed of a linear servo cart system. Integer order controller based on proportional derivative (PD) approach is also shown for comparison. Simulation responses are presented and analyzed, in this investigation. The superiority of state space approach based fractional order controller is shown in the results. The paper contains a literature review on several control techniques used to control position and speed of a servo-cart system. An over view of mathematical modeling of servo cart system and a description of a proposed fractional controller is presented in this paper. A brief description of integer order control scheme is also presented. Simulated results are compared and discussed for both fractional order controller and integer order controller at the end of this paper