The paper reviews the current state of development of a CAD facility for the design and evaluation of industrial process control systems. The facility is generalised to support multiple control systems and to coordina...
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The paper reviews the current state of development of a CAD facility for the design and evaluation of industrial process control systems. The facility is generalised to support multiple control systems and to coordinate their operations. The individual control systems may involve compensation for interaction, disturbance and time delay. The design procedures use least-squares analysis for identification, dynamic programming for control system design and simulation for evaluation of performance. The facility permits a systematic approach for building sets of hierarchical controllers with the objective of supervising the operation of complex processes. Design studies relating to real plant data are presented.
It is expected that soon there will be a significant number of unmanned aerial vehicles (UAVs) operating side-by-side with manned civil aircraft in national airspace systems. To be able to integrate UAVs safely with c...
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It is expected that soon there will be a significant number of unmanned aerial vehicles (UAVs) operating side-by-side with manned civil aircraft in national airspace systems. To be able to integrate UAVs safely with civil traffic, a number of challenges must be overcome first. This study investigates situational awareness of UAVs' autonomous taxiing in an aerodrome environment. The research work is based on a real outdoor experimental data collected at the Walney Island Airport, the UK. It aims to further develop and test UAVs' autonomous taxiing in a challenging outdoor environment. To address various practical issues arising from the outdoor aerodrome such as camera vibration, taxiway feature extraction, and unknown obstacles, the authors develop an integrated approach that combines the Bayesian-network based semantic segmentation with a self-learning method to enhance situational awareness of UAVs. Detailed analysis of the outdoor experimental data shows that the integrated method developed in this study improves the robustness of situational awareness for autonomous taxiing.
In the work presented here, we study a cooperative control problem for a network of uninhabited air vehicles (UAVs) where it is assumed that after deployment a set of tasks is given to a group of UAVs and the UAVs mus...
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In the work presented here, we study a cooperative control problem for a network of uninhabited air vehicles (UAVs) where it is assumed that after deployment a set of tasks is given to a group of UAVs and the UAVs must cooperate to decide which UAV should process each task. The cooperation must occur during real-time operation due to a need to repeatedly process each task, in spite of imperfect communications (e.g., messages with random but bounded delays), and the possibility that tasks "pop-up." We show how to view this as a cooperative scheduling problem, and how to derive bounds on mission-level performance metrics. Simulations are used to compare the approach with a noncooperative strategy and to provide design guidelines for the cooperative scheduler.
The compatibility of AC propulsion systems with coded train detection and on-board speed code reception systems is always a concern. A review of an automatic train control system commissioned for Greater Cairo Metro S...
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The compatibility of AC propulsion systems with coded train detection and on-board speed code reception systems is always a concern. A review of an automatic train control system commissioned for Greater Cairo Metro System is presented. The compatibility of track-to-train transmission with the inverter-controlled AC drive and the 750 V DC third-rail power supply is also examined.
An implementation of vector control for induction motors is presented, where there is no need for information concerning the rotor flux position and matrix transformations. It shows how the stator reference phase curr...
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An implementation of vector control for induction motors is presented, where there is no need for information concerning the rotor flux position and matrix transformations. It shows how the stator reference phase currents can be generated and changed in real time from digitally stored sinewaves, so to achieve independent control of torque at constant rotor flux. Experimental evaluation of the new scheme is made for sudden changes in the load torque and for the step changes of the speed reference signal. The arrangement of a DC load system enabling sudden changes in load torque is also described.
Cape Town City Council is responsible for the supply of electricity to the city area. To achieve this, the council owns and operates thermal and pumped-storage power stations and extensive HV transmission and LV distr...
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Cape Town City Council is responsible for the supply of electricity to the city area. To achieve this, the council owns and operates thermal and pumped-storage power stations and extensive HV transmission and LV distribution networks. Power is also purchased from the national supply authority. Prior to the introduction of the control system described in this paper limited supervisory control and data acquisition facilities existed to provide some degree of remote control for the network. In addition to duties associated with supervision of both the HV and LV networks, the control centre operators were also responsible for energy management involving generator scheduling and control, and load-shedding when required. To assist the operators in their extensive and onereous duties a new computer-based control centre has been developed and was commissioned in 1984. Because of the unusual mix of power sources special software had to be developed for energy management purposes. Descriptions are given of the functional and practical aspects of the control centre, and of associated hardware and software facilities and also some commissioning experiences.
Tailoring cloud support for each autonomous-driving application would require maintaining multiple infrastructures, potentially resulting in low resource utilization, low performance, and high management overhead. To ...
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Tailoring cloud support for each autonomous-driving application would require maintaining multiple infrastructures, potentially resulting in low resource utilization, low performance, and high management overhead. To address this problem, the authors present a unified cloud infrastructure with Spark for distributed computing, Alluxio for distributed storage, and OpenCL to exploit heterogeneous computing resources for enhanced performance and energy efficiency.
Photovoltaic (PV) emulator (PVE) is a non-linear power supply that produces a similar output to that of the PV module. It requires a closed-loop controller such as the proportional-integral (PI) and fuzzy logic contro...
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Photovoltaic (PV) emulator (PVE) is a non-linear power supply that produces a similar output to that of the PV module. It requires a closed-loop controller such as the proportional-integral (PI) and fuzzy logic controllers to operate properly. The PI controller has a low-computational burden and is not robust since the transient response varies under different load conditions. Although the fuzzy logic controller is robust, it requires high-computation capability. This study proposed an alternative approach called the shift controller for the PVE to easily compute and maintain a fast transient response under various load conditions. The performance of the proposed shift controller for the PVE is compared with the performance of the PVEs using the PI and fuzzy logic controllers, respectively. The controllers are simulated using MATLAB/Simulink and implemented using dSPACE ds1104 for experimental validation. The results show that the proposed shift controller computes up to 18 times faster than the fuzzy logic controller. The proposed controller also responds faster to load change than the PI controller.
Self tuning is an important new branch of control which is attracting increasing theoretical and practical interest. The objective of self tuning is to control systems with unknown constant or slowly varying parameter...
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Self tuning is an important new branch of control which is attracting increasing theoretical and practical interest. The objective of self tuning is to control systems with unknown constant or slowly varying parameters, so theoretical interest is concerned with the stability, performance and convergence of the recursive algorithms involved, while practical interest derives from its potential as a simple controller commissioning tool, both as a method for controlling time-varying or nonlinear plant over a range of operating points, and for dealing with batch problems where the plant or materials vary over successive batches. This paper summarises and expands previous work on the design of self-tuning controllers. It discusses the closed-loop properties of various classes of self tuner, convergence concepts and results, and some of the technical problems involved with implementing self tuners on small computers or microprocessors.
The paper is concerned with the investigation of a multiserver computer-controlled queuing system with preemptive priorities and feedback. A formula for the generating function of the state probabilities of the system...
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The paper is concerned with the investigation of a multiserver computer-controlled queuing system with preemptive priorities and feedback. A formula for the generating function of the state probabilities of the system is derived and a method using the transition probabilities of a Markov chain for determining the first waiting-time distribution in the system is presented.
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