The control platform of the induction motor （IM） with low costs is developed by using DSP MC56F8013 with a good performance/price rtaio. The control algorithm for the speed sensorless IM is studied based on the stat...
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The control platform of the induction motor （IM） with low costs is developed by using DSP MC56F8013 with a good performance/price rtaio. The control algorithm for the speed sensorless IM is studied based on the stator flux orientation （SFO）. The algorithm structure is simple to be implemented and cannot be influenced by motor parameters, The improved stator flux estimation is used to compensate errors caused by the low pass filter （LPF）. A new speed regulator is designed to ensure the system working with the maximal torque in the transient state. The system simulation and the prototype experiment are made. Results show that the con- trol system has good dynamic and static performance.
This paper describes novel multi-electrode systems that can autonomously position recording electrodes inside cortical tissue so as to isolate and then maintain optimal extracellular signal recording quality without h...
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ISBN:
(纸本)9781424400393
This paper describes novel multi-electrode systems that can autonomously position recording electrodes inside cortical tissue so as to isolate and then maintain optimal extracellular signal recording quality without human intervention. Autonomous microdrives can be used to improve the quality and efficiency of acute recordings that are needed for basic research in neurophysiology. They also offer the potential to increase the longevity and quality of chronic recordings and will serve as the front end of neuroprosthetic systems that aid the handicapped. We first describe the autonomous positioning algorithm, and its implementation as a finite state machine. We have deployed the algorithm on both conventional acute recording micro-drives and a novel miniature robot microdrive. Experimental results in monkey cortex are presented.
This paper introduces briefly the principles of container CT inspection system, and illustrates the composition of the PID control subsystem. It also introduces the control algorithm of PID controller and the method o...
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This paper introduces briefly the principles of container CT inspection system, and illustrates the composition of the PID control subsystem. It also introduces the control algorithm of PID controller and the method of adjusting PID parameters in detail. It is proved that the rapid response and the high accuracy of locating for the inspection system can be met by using PID controller with appropriate PID parameters.
Experimental results are presented on successful application of delayed-feedback control algorithms for tracking unstable steady states and periodic orbits of electrochemical dissolution systems. Time-delay autosynchr...
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Experimental results are presented on successful application of delayed-feedback control algorithms for tracking unstable steady states and periodic orbits of electrochemical dissolution systems. Time-delay autosynchronization and delay optimization with a descent gradient method were applied for stationary states and periodic orbits, respectively. These tracking algorithms are utilized in constructing experimental bifurcation diagrams of the studied electrochemical systems in which Hopf, saddle-node, saddle-loop, and period-doubling bifurcations take place. (c) 2006 American Institute of Physics.
The control algorithm of an active rectifier is presented in this paper. This kind of an active rectifier, produced by A.D. EMO - Ohrid, R. Macedonia, is used as a battery in all substations. The control algorithm con...
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The control algorithm of an active rectifier is presented in this paper. This kind of an active rectifier, produced by A.D. EMO - Ohrid, R. Macedonia, is used as a battery in all substations. The control algorithm contains main program, several subprograms and three interrupt routines. Also, the active rectifier, as an industrial product is presented, as well as the innovations, in comparison to the Siemens one. This algorithm has been tested in a laboratory and the results show its efficiency.
The linear quadratic regulator (LQR) control algorithm is at the heart of many modem control design methods. There have been numerous publications dealing with LQR control and earthquake engineering. However, very few...
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The linear quadratic regulator (LQR) control algorithm is at the heart of many modem control design methods. There have been numerous publications dealing with LQR control and earthquake engineering. However, very few papers discuss the hysteretic loops produced by the LQR control force, although in the earthquake engineering field, hysteretic loops have been the key part of seismic designs. This paper shows the importance of investigating the hysteretic loops produced by the LQR control force for seismic response, and proposes a method to reproduce the hysteretic loops with a much simpler algorithm. The investigation was carried out on a cable-stayed bridge model controlled either by the LQR algorithm, viscous damper, or the proposed method. The results show that the proposed method is capable of reducing seismic response better than the viscous damper case and is similar to the LQR case. The practical applicability of the proposed method is also investigated by using a variable-orifice oil damper as the controlling device. The proposed method needs only displacement response at the device location, and therefore fewer sensors are needed than for the LQR algorithm. Copyright (c) 2005 John Wiley & Sons, Ltd.
The effect of feedback flow control on the wake of a circular cylinder at a Reynolds number of 100 is investigated in direct numerical simulation. The control approach uses a low-dimensional model based on proper orth...
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The effect of feedback flow control on the wake of a circular cylinder at a Reynolds number of 100 is investigated in direct numerical simulation. The control approach uses a low-dimensional model based on proper orthogonal decomposition (POD). The controller applies linear proportional, and differential feedback to the estimate of the first POD mode. The range of validity of the POD model is explored in detail. Actuation is implemented as displacement of the cylinder normal to the flow. It is demonstrated that the threshold peak amplitude below which the control actuation ceases to be effective is in the order of 5% of the cylinder diameter. The closed-loop feedback simulations explore the effect of both fixed-phase and variable-phase feedback on the wake. Whereas fixed-phase feedback is effective in reducing drag and unsteady lift, it fails to stabilize this state once the low drag state has been reached. Variable-phase feedback, however, achieves the same drag and unsteady lift reductions while being able to stabilize the flow in the low drag state. In the low drag state, the neat wake is entirely steady, whereas the far wake exhibits vortex shedding at a reduced intensity. A drag reduction of 15% of the drag was achieved, and the unsteady lift force was lowered by 90%.
Objective: To outline a roadmap to the artificial pancreas (AP) comprising a subcutaneous (sc) glucose monitor, a control algorithm, and an insulin pump delivering sc insulin. Research design and methods: A literature...
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Objective: To outline a roadmap to the artificial pancreas (AP) comprising a subcutaneous (sc) glucose monitor, a control algorithm, and an insulin pump delivering sc insulin. Research design and methods: A literature review, personal views, and material from the Juvenile Diabetes Research Foundation have been used to prepare the roadmap. Results: The roadmap identifies sensor reliability but not sensor accuracy as the critical roadblock, which can be addressed by advanced control algorithms combined with safety critical features. It is argued that incremental rather than perfect glucose control should be the objective of the first generation of the AP. Overnight glucose control is more easily achieved than postmeal control and could be the first aim for a commercial AP. Glycated haemoglobin and the risk of hypoglycaemia will remain the primary efficacy and safety measures being accompanied by complementary measures of variability of glucose excursions. Research priorities include the development of AP prototypes incorporating existing glucose monitors with focus on evaluation at home over short- and long-term periods. Conclusions: The AP promises to revolutionise insulin treatment. Building on technological progress in glucose sensing, the true potential of the AP needs to be assessed by building prototypes and evaluations in home settings. (c) 2006 Elsevier Ireland Ltd. All rights reserved.
Recent global efforts to resolve environmental issues are required in sheet metal forming. For this reason, some research projects have been focused on unlubricated processes as well as on the use of volatile lubrican...
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Recent global efforts to resolve environmental issues are required in sheet metal forming. For this reason, some research projects have been focused on unlubricated processes as well as on the use of volatile lubricants. However, low formability due to poor lubrication conditions is still a matter of concern. In this study, in order to improve the friction conditions, a new algorithm for controlling blank holding force (BHF) and punch speed (SPD) was proposed. The concept is to separate the wrinkle eliminating process from drawing process. That is, the process proceeds with an extremely low BHF until a wrinkle sufficiently grows, and the wrinkle is eliminated by BHF loading without punch penetration. Its effectiveness was investigated by finite element (FE) simulation, in which two blank models (0.5 mm and 1.0 mm thickness) were used. As a result, the maximum forming forces decreased by 5.33% (0.5 mm) and 1.55% (1.0 mm) compared with those of the uncontrolled model at a constant minimum BHF. In addition, a thinner blank sheet is better for the algorithm on the basis of the result that cup height decreases and thickness distribution increases in the case of 0.5 mm thickness.
Experimental results are presented on the active control of a backward-facing step flow revealing some features observed in combustion chambers. These experiments were performed under nonreactive conditions, and the e...
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Experimental results are presented on the active control of a backward-facing step flow revealing some features observed in combustion chambers. These experiments were performed under nonreactive conditions, and the effect of the pressure fluctuations induced by the unsteady heat release was simulated by an external acoustic excitation produced by two loudspeakers placed far downstream from the step., This excitation signal was delivered by a generator or by a hot-wire probe placed in the shear layer. The latter configuration reproduces some aspects of the actual coupling that have been observed with combustion instabilities. This preexcited flow was then controlled using six synthetic jets located on the vertical side of the step. The control loop uses an recursive least-mean-square autoadaptive algorithm applied to a signal from either a microphone or a hot-wire probe placed downstream of the step edge. The influence of the external acoustic excitationon the flow organization and the effect of the control loop are described. Without excitation, the control algorithm is not able to reduce the natural unsteady phenomena. However, it does damp the shear-layer pressure or velocity fluctuations intensified by an external excitation and bring the flow close to its natural feature. The efficiency of the control depends on the frequency of the external excitation, the signal used in the control loop, and the phase shift between the velocity and the pressure signals in the shear layer.
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