For any two n-th order polynomials a(s) and b(s), the Hurwitz stability of their convex combination is necessary and sufficient for the existence of a polynomial c(s) such that c(s)/a(s) and c(s)/b(s) are both strictl...
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In this paper a non-linear fuzzy autopilot for ship track-keeping is presented. The proposed autopilot has four inputs (actual and desired heading, rate of change of heading and offset from the desired path) and one o...
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In this paper a non-linear fuzzy autopilot for ship track-keeping is presented. The proposed autopilot has four inputs (actual and desired heading, rate of change of heading and offset from the desired path) and one output (command rudder angle). The track-keeping problem is decomposed into two subtasks: (i) followthe desired heading, and (ii) bring the ship onto the desired path and keep tracking. Internally, the autopilot consists of two autopilots that fulfil these tasks simultaneously. The proposed control scheme has been verified using a non-linear model of a Mariner-class vessel and steering mechanism under the influence of wave and current disturbances. Results presented show how such a control strategy enables improved tracking performance.
A design approach of the initial state of the repetitive controller is proposed in this paper. The approach makes full use of the feature of the digital controller and optimizes the transient response without perplexi...
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A design approach of the initial state of the repetitive controller is proposed in this paper. The approach makes full use of the feature of the digital controller and optimizes the transient response without perplexing the controller. A numerical example is presented to illustrate the validity of the approach.
A design approach of the initial state of the repetitive controller is proposed in this paper. The approach makes full use of the feature of the digital controller and optimizes the transient response without perplexi...
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A design approach of the initial state of the repetitive controller is proposed in this paper. The approach makes full use of the feature of the digital controller and optimizes the transient response without perplexing the controller. A numerical example is presented to illustrate the validity of the approach.
A 3-phase, 30 kVA, 4 pole, 1800 rpm superconducting generator is built and tested. The field winding of the rotor is a racetrack type with NbTi superconducting wire. The rotor is composed of two dampers and a liquid h...
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A 3-phase, 30 kVA, 4 pole, 1800 rpm superconducting generator is built and tested. The field winding of the rotor is a racetrack type with NbTi superconducting wire. The rotor is composed of two dampers and a liquid h...
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A 3-phase, 30 kVA, 4 pole, 1800 rpm superconducting generator is built and tested. The field winding of the rotor is a racetrack type with NbTi superconducting wire. The rotor is composed of two dampers and a liquid helium container in which the field poles reside. The space between the outermost damper and the container is vacuum insulated. To continuously transfer the liquid helium from the stationary dewar into the rotor and return the helium gas conversely, a special coupling is installed. The stationary coupling is connected to the rotor through a ferrofluid seal. The open circuit characteristic (OCC) and short circuit characteristic (SCC) are obtained. Also, the test results under the light load (up to 3.6 kW) are given. From the design stage, 2-D FE analysis coupled with the external circuit has been performed. The external circuit includes the end winding resistance and reactance as well as two dampers. When compared with the test data, the FE analysis results show a very good agreement.
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