Special features of processes of switching of thyristor AC bridges, as a part of a high-power thyristor controlled phase shifter (TCPS), are considered. Influence of mutual magnetic coupling of secondary windings of a...
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ISBN:
(纸本)9781467367196
Special features of processes of switching of thyristor AC bridges, as a part of a high-power thyristor controlled phase shifter (TCPS), are considered. Influence of mutual magnetic coupling of secondary windings of an excitation transformer on an interval of safety switching of a thyristor switch of TCPS is experimentally discovered and theoretically justified. Results of experiments, confirming presence of an effect of serial switching of secondary windings of an excitation transformer in an interval of slow (long period) switching and an effect of acceleration of a process of switching in an interval of fast (shot period) switching, are presented.
This research presents a time-of-arrival control algorithm designed to account for the effects of steady-state wind and time-variant terminal constraints. The algorithm is based upon previous research into a control a...
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ISBN:
(数字)9781624106095
ISBN:
(纸本)9781624106095
This research presents a time-of-arrival control algorithm designed to account for the effects of steady-state wind and time-variant terminal constraints. The algorithm is based upon previous research into a control algorithm framework which assumed a ground-fixed reference trajectory in order to improve arrival time performance. This research utilizes a different method to estimate the time to complete a turn with non-zero wind. The arrival time estimate in this paper is based on the principles of aircraft navigation assuming a constant bank angle turn. The performance of the controller was evaluated using a fighter-like aircraft model traveling at 846 ft/s. Static end point simulation results showed the controller was able to achieve less than one second of arrival time error for wind speeds less than 300 ft/s when a feasible arrival time was selected. The moving target results showed the aircraft could perform multiple passes of a target moving at 150 ft/s regardless of direction but could only compensate for a target traveling at 30 ft/s during all non-cooperative scenarios.
Complex mineral raw materials processing is an essential operation in modern industry. Innovative technologies help in constant improving of the efficiency and performance. The paper presents a design of electromagnet...
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Complex mineral raw materials processing is an essential operation in modern industry. Innovative technologies help in constant improving of the efficiency and performance. The paper presents a design of electromagnetic mill, its technological structure and control system. In comparison to conventional solutions, the electromagnetic mill is a fully automated system. It operates in more effective way. The proper selection of the physical and process parameters of the system is crucial for efficiency of the process. The device stands out because of its low energy consumption. The air stream ratio model has been presented for the dry grinding and classification unit with the electromagnetic mill. The concept of the grinding system is described along with indirect measurement methodology. Supervisory control algorithm based on the model structure is derived. (C) 2017, IFAC (International Federation of Automatic control) Hosting by Elsevier Ltd. All rights reserved.
This paper illustrates a proof of concept in coupling decision-making with traditional control algorithms for aerospace applications. Autonomy software sometimes requires augmenting conventional control algorithms wit...
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ISBN:
(数字)9781624106095
ISBN:
(纸本)9781624106095
This paper illustrates a proof of concept in coupling decision-making with traditional control algorithms for aerospace applications. Autonomy software sometimes requires augmenting conventional control algorithms with arbitrary logic code, rendering stability analysis difficult or impossible. With rigorous convergence results elusive, an alternative is to improve decision-making to the extent possible to maintain the aircraft's overall safety. To illustrate, we introduce a pitch control system that uses a system monitor (cognition) to cluster modules of similar intent to decide on a malfunctioning module's invalidity based on the pilot's intent.
In this paper, a 3-leg voltage source inverter (VSI) based Distribution Static Compensator (DSTATCOM) is used for load compensation in 3-phase 3-wire distribution system. The control algorithm is based on Synchronous ...
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ISBN:
(纸本)9781479940400
In this paper, a 3-leg voltage source inverter (VSI) based Distribution Static Compensator (DSTATCOM) is used for load compensation in 3-phase 3-wire distribution system. The control algorithm is based on Synchronous Reference Frame (SRF) algorithm. This algorithm is used for extracting the reference source currents for power factor correction, load balancing and harmonic reduction. Tuning of PI (Proportional Integral) controller is done using trial and error method and also by Zeigler-Nichols (Z-N) method. Simulations are performed for various load conditions such as a reactive linear load, an unbalanced load and non-linear load. Power factor correction mode (PFC) for DSTA TCOM is tested in MA TLAB environment using SIMULINK and SimPower system toolbox.
This paper presents some results on a remote hands-on activity for aerospace education performed at the French Air Force Academy. For this purpose, a Parrot Mambo Fly minidrone is studied and flew to illustrate and co...
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ISBN:
(数字)9781624106095
ISBN:
(纸本)9781624106095
This paper presents some results on a remote hands-on activity for aerospace education performed at the French Air Force Academy. For this purpose, a Parrot Mambo Fly minidrone is studied and flew to illustrate and connect skills developed through a stability and control course for aerospace undergraduate cadets. The activity, conducted outside of the classrooms, consists of a theoretical approach where the cadets analyze the system and calculate an adapted controller to improve the performance. After a series of simulations, an actual flight is remotely performed. Despite the absence of physical interaction with the material, the results show that a high level of engagement of the cadets is preserved thanks to the protocol used during this activity. These results are also compared to a more theoretical approach including only a set of simulations.
As Cyber-Physical Systems (CPS) become more integrated into everyday life, the security of these systems must also be considered during their development due to their ever increasing importance. With the increase of p...
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ISBN:
(数字)9781624107115
ISBN:
(纸本)9781624107115
As Cyber-Physical Systems (CPS) become more integrated into everyday life, the security of these systems must also be considered during their development due to their ever increasing importance. With the increase of physical components in the system, more autonomous control requirements, and increased dependence on proper functionality, verifying system safety and correct operation becomes increasingly difficult. CPS have become more complex through the combination of additional hardware and more interconnected software resulting in many different layers, each one requiring individual security solutions. One example of such a safety-critical CPS embedded system is the Flight control System (FCS) of an Unmanned Aerial System (UAS). An FCS consists of many complex sensors that provide aircraft state information to a central processor, the autopilot, which executes the programmed flight control firmware. Developers of an FCS are dependent on a varying supply chain for the sensors and processors in use, and the trusted delivery of their verified firmware updates to the end user cannot always be guaranteed. Over time, sensor data can become less reliable as sensors can deteriorate resulting in eventual failure. These factors lead to system vulnerabilities from various types of cyber-attacks and physical faults of the sensors on a UAS. Statistical techniques are analyzed for their effectiveness in detecting when specified sensor values begin to exhibit a variance from other trusted sources. A real-time functional run-time assurance architecture and associated detection techniques has been developed to detect such cyber-attacks and sensor data faults in a UAS FCS. The results are demonstrated using an FPGA-based Hardware-in-the-loop Simulation testbed for simulating attacks and the attack detection algorithms to provide the user with information regarding these sensor attacks.
In this paper, an advanced control algorithm in single-phase active rectifier for reduction of grid current harmonics is presented. In addition to PI current controller, three advanced types of controllers are investi...
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ISBN:
(纸本)9781538678909
In this paper, an advanced control algorithm in single-phase active rectifier for reduction of grid current harmonics is presented. In addition to PI current controller, three advanced types of controllers are investigated: resonant, discrete cosine transforms (DCT) and repetitive controller. These controllers are able to effectively reduce harmonics, caused by periodic disturbances. A simulation model has been built to test the proposed algorithms. Simulation results confirm significant improvement in grid current harmonic content, achieved by these advanced current controllers. Analysis of memory usage and computing power requirements is also provided.
The present work deals with the design and validation of a formation flight control algorithm able to manage five aircraft simulated using a linear model representative of a a medium altitude, long endurance unmanned ...
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ISBN:
(数字)9781624107047
ISBN:
(纸本)9781624107047
The present work deals with the design and validation of a formation flight control algorithm able to manage five aircraft simulated using a linear model representative of a a medium altitude, long endurance unmanned airplane. The proposed approach is based on the artificial potential field and it is validated both in bi-dimensional and three-dimensional spaces. Even though the aircraft models are time-invariant, the external environment is simulated to be time-variant. In fact, within the simulation it is possible to simulate intruders, or object moving with its own dynamics, and no-fly zones.
Most noise shaping (NS) SAR ADCs still use the same control algorithm as Nyquist SAR ADC. Noticing the slow-varying input under oversampling, this paper proposed a new algorithm named quantization-error-matched RLSB-f...
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ISBN:
(纸本)9798350361766;9798350361759
Most noise shaping (NS) SAR ADCs still use the same control algorithm as Nyquist SAR ADC. Noticing the slow-varying input under oversampling, this paper proposed a new algorithm named quantization-error-matched RLSB-first to improve the switching efficiency. Compared with the VCM-based algorithm, the proposed algorithm saves 87.3% switching power consumption in a 1st order NS SAR under an OSR of 25. Simulated under a 55nm CMOS process, the NS SAR ADC based on the proposed algorithm achieves an SNDR of 87.2dB with a 20kHz signal bandwidth. Operating at 2.8kS/s sampling rate, it consumes 12.1 mu W power, corresponding to a Schreier FoM of 179.4dB.
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