Hierarchical variable structure control for aerospace systems

Legacy description not available</p

Variable structure switched gain stabilisation for systems with saturation non-linearities

Legacy description not available</p

Improved performance of industrial servo-drive systems by saw shaft torque feedback

Legacy description not available</p

Towards determination of critical speeds of a rotating shaft with eccentric sleeves: equations of motion

A primary problem in the turbine industry is associated with the mitigation of bending vibration modes of high-speed rotating shafts. This is especially pertinent at speeds approaching the critical frequencies. Here, a shaft, complete with eccentric sleeves at the free ends, is designed and developed, with a view to passively control critical speeds and vibration induced bending. In this article, using the Extended Hamiltonâ??s principle, the equations of motion (axial, torsional, inplane and out-of-plane bending) for a rotating flexible shaft are derived; considering non-constant rotating speed, Coriolis and centrifugal forces, with the associated boundary conditions due to the eccentric sleeves and torsional springs in angular deformations of lateral vibrations in bending. The numerical dynamic analysis showed that considering the sleeves as flexible only had a small effect upon the first critical speed of the shaft. Therefore, rigid body modelling of the sleeves is sufficient to capture the essential dynamics of the system. The derived equations of motion with the associated boundary conditions show that in the case of constant rotating speed, the eccentric sleeves are coupling xy-bending with xz-bending and also torsion. Also the derived equations of motion and the associated boundary conditions in the case of non-constant rotating speed are essentially nonlinear due to inertia terms. This work is essential to the advance of linear and nonlinear dynamic analysis of the system by means of determination of normal modes and critical speeds of the shaft. © Springer International Publishing Switzerland 2015.</p

Regenerative braking for all-electric and hybrid electric vehicles

Legacy description not available</p

Coprime factorisation techniques for multi-axis motion control

Legacy description not available</p

Improved tracking control of industrial servo-drive system by saw torque feedback

This paper provides a comparative, systematic analysis of conventional and non-conventional velocity control algorithms for a two-inertia mechanical system. T he assessment criterion is based on the integral of time multiplied by absolute error performance index, normalized as a function of the mechanical parameters, allowing a direct comparison between simple proportional-integral and more complex control schemes. Tuning methods for extended control structures are presented and performances evaluated using the dynamics of a commonly employed proportional-integral controller as a benchmark for assessment. It has been shown that the required controller complexity to provide good performance is directly related the mechanical system parameters and is most critical when the load inertia is smaller than that of the motor. Extended structures incorporating a torque feedback signal derived from a low cost, surface acoustic wave transducer are presented and shown to significantly improve the tracking performance of the classical proportional-integral controller.</p

Extracting underlying trend and predicting power usage via joint SSA and sparse binary programming

This paper proposes a novel methodology for extracting the underlying trend and predicting the power usage through a joint singular spectrum analysis (SSA) and sparse binary programming approach. The underlying trend is approximated by the sum of a part of SSA components, in which the total number of the SSA components in the sum is minimized subject to a specification on the maximum absolute difference between the original signal and the approximated underlying trend. As the selection of the SSA components is binary, this selection problem is to minimize the L0 norm of the selection vector subject to the L? norm constraint on the difference between the original signal and the approximated underlying trend as well as the binary valued constraint on the elements of the selection vector. This problem is actually a sparse binary programming problem. To solve this problem, first the corresponding continuous valued sparse optimization problem is solved. That is, to solve the same problem without the consideration of the binary valued constraint. This problem can be approximated by a linear programming problem when the isometry condition is satisfied, and the solution of the linear programming problem can be obtained via existing simplex methods or interior point methods. By applying the binary quantization to the obtained solution of the linear programming problem, the approximated solution of the original sparse binary programming problem is obtained. Unlike previously reported techniques that require a pre-cursor model or parameter specifications, the proposed method is completely adaptive. Experiment results show that our proposed method is very effective and efficient for extracting the underlying trend and predicting the power usage. © 2013 IEEE</p

Simulation and experimental validation of induction machine dynamics driving multi-inertial loads

Legacy description not available</p

Simulation of a scheduling control scheme for domestic central heating systems in the UK

Gas fired space heating is responsible for 24 of the UK's energy consumption [1] and 14% of the UK's CO2 emissions [2]. This paper provides a brief overview of current domestic heating installation practice in the UK and introduces a novel simulation technique. Finally, the paper demonstrates that communicating radiator valves when used in conjunction with a reverse modulation control technique, represent an opportunity to achieve a reduction of 86.1kg of CO2 emissions per household per annum for an average UK household.</p