scholarly journals A Comparative Study of Formation Control at the Earth-Moon L₂ Libration Point

2021 ◽  
Author(s):  
Waqas A. Manzoor
Keyword(s):  
Formation Control ◽  
Controller Design ◽  
Libration Point ◽  
Control Strategies ◽  
Control Input ◽  
Control Methods ◽  
Space Applications ◽  
Affine Systems ◽  
The Earth ◽  
And Control

This thesis examines the performance of control methods that fall under the optimal, predictive and adaptive classifications, subjected to sensor/actuator faults, and presents approaches to apply them to non-affine systems utilizing single thruster and solar sail actuator configurations. The system of interest consists of a leader-follower satellite formation near the L2 point of the Earth-Moon system. The control methods studied here include those which are emerging in the space systems literature, and are evaluated in terms of their transient and steady state responses, and control input variation. Numerical simulation of faults affecting both sensor and propulsion actuator systems are conducted, along with an experiment to validate the results in a laboratory environment. The observed behavioral characteristics in the simulations match those demonstrated in the experiment. Alternative representations of dynamics were explored for controller design of non-affine systems. The research presented herein provides support for the usage of the proposed control strategies in future space applications.

scholarly journals A Comparative Study of Formation Control at the Earth-Moon L₂ Libration Point

2021 ◽  
Author(s):  
Waqas A. Manzoor
Keyword(s):  
Formation Control ◽  
Controller Design ◽  
Libration Point ◽  
Control Strategies ◽  
Control Input ◽  
Control Methods ◽  
Space Applications ◽  
Affine Systems ◽  
The Earth ◽  
And Control

This thesis examines the performance of control methods that fall under the optimal, predictive and adaptive classifications, subjected to sensor/actuator faults, and presents approaches to apply them to non-affine systems utilizing single thruster and solar sail actuator configurations. The system of interest consists of a leader-follower satellite formation near the L2 point of the Earth-Moon system. The control methods studied here include those which are emerging in the space systems literature, and are evaluated in terms of their transient and steady state responses, and control input variation. Numerical simulation of faults affecting both sensor and propulsion actuator systems are conducted, along with an experiment to validate the results in a laboratory environment. The observed behavioral characteristics in the simulations match those demonstrated in the experiment. Alternative representations of dynamics were explored for controller design of non-affine systems. The research presented herein provides support for the usage of the proposed control strategies in future space applications.

On the Use of Actively Controlled Auxiliary Bearings in Magnetic Bearing Systems

2008 ◽  
Author(s):  
Iain S. Cade ◽  
M. Necip Sahinkaya ◽  
Clifford R. Burrows ◽  
Patrick S. Keogh
Keyword(s):  
Controller Design ◽  
Control Strategies ◽  
Frictional Heating ◽  
Magnetic Bearing ◽  
Contact Forces ◽  
Active Magnetic Bearing ◽  
Physical Limit ◽  
Drop Tests ◽  
Auxiliary Bearing ◽  
And Control

Auxiliary bearings are used to prevent rotor/stator contact in active magnetic bearing systems. They are sacrificial components providing a physical limit on the rotor displacement. During rotor/auxiliary bearing contact significant forces normal to the contact zone may occur. Furthermore, rotor slip and rub can lead to localized frictional heating. Linear control strategies may also become ineffective or induce instability due to changes in rotordynamic characteristics during contact periods. This work considers the concept of using actively controlled auxiliary bearings in magnetic bearing systems. Auxiliary bearing controller design is focused on attenuating bearing vibration resulting from contact and reducing the contact forces. Controller optimization is based on the H∞ norm with appropriate weighting functions applied to the error and control signals. The controller is assessed using a simulated rotor/magnetic bearing system. Comparison of the performance of an actively controlled auxiliary bearing is made with that of a resiliently mounted auxiliary bearing. Rotor drop tests, repeated contact tests, and sudden rotor unbalance resulting in trapped contact modes, are considered.

A Comparative, Experimental Study of Model Suitability to Describe Vehicle Rollover Dynamics for Control Design

2005 ◽  
Author(s):  
John T. Cameron ◽  
Sean Brennan
Keyword(s):  
Experimental Validation ◽  
Controller Design ◽  
Experimental Testing ◽  
Control Strategies ◽  
Control Design ◽  
Experimental Results ◽  
Dynamics And Control ◽  
Vehicle Rollover ◽  
And Control ◽  
Future Work

This work presents results of an initial investigation into models and control strategies suitable to prevent vehicle rollover due to untripped driving maneuvers. Outside of industry, the study of vehicle rollover inclusive of both experimental validation and practical controller design is limited. The researcher interested in initiating study on rollover dynamics and control is left with the challenging task of identifying suitable vehicle models from the literature, comparing these models with experimental results, and determining suitable parameters for the models. This work addresses these issues via experimental testing of published models. Parameter estimation data based on model fits is presented, with commentary given on the validity of different methods. Experimental results are then presented and compared to the output predicted by the various models in both the time and frequency domain in order to provide a foundation for future work.

Decentralized Robust Vibration Control of Smart Structures with Parameter Uncertainties

2011 ◽  
Vol 22 (2) ◽  
pp. 137-147 ◽  
Author(s):  
Jian-Ping Jiang ◽  
Dong-Xu Li
Keyword(s):  
Vibration Control ◽  
Controller Design ◽  
Damping Ratio ◽  
External Disturbance ◽  
Composite Panel ◽  
Linear Matrix ◽  
Control Input ◽  
Parameter Uncertainties ◽  
Modal Damping ◽  
And Control

This study deals with decentralized robust vibration control of a smart composite panel with parameter uncertainties. The composite panel with four collocated piezoelectric actuators and velocity sensors is modeled using finite element method, and then the size of the model is reduced in the state space using Modal Hankel Singular Value. The parameter uncertainties presented by natural frequencies and modal damping ratios are considered in controller design process. To suppress the vibration induced by external disturbance, a decentralized robust H∞ controller is developed using linear matrix inequality techniques. Numerical simulation for the smart panel is performed in order to investigate the effectiveness of decentralized vibration control (DVC). When the system is subjected to an initial displacement field or distributed white noise disturbance, numerical results show that the DVC system is very effective. Although there are 20% parameter uncertainties for modal frequencies, damping ratio, and control input, the decentralized controller can effectively suppress the vibration excited by the external disturbance. Furthermore, the decentralized controller composed of four three-order systems can be practically implemented well.

Operation of Microgrid and Control Strategies

2019 ◽  
pp. 434-449
Author(s):  
Suma Deepthi Veeraganti ◽  
Ramchandra Nittala
Keyword(s):  
Electric Power ◽  
Rural Areas ◽  
Control Strategies ◽  
Electric Power Industry ◽  
Power Industry ◽  
Current Control ◽  
Frequency Regulation ◽  
Control Methods ◽  
Islanded Mode ◽  
And Control

Microgrids are the most innovative area in the electric power industry today. A microgrid can operate in grid-connected or islanded mode. In islanded mode, microgrids can provide electricity to the rural areas with lower cost and minimum power losses. Several methods have been proposed in the literature for the successful operation of a microgrid. This chapter presents an overview of the major challenges and their possible solutions for planning, operation, and control of islanded operation of a microgrid. Microgrids are the most innovative area in the electric power industry today. Moreover, microgrids provide local voltage and frequency regulation support and improve reliability and power capacity of the grid. The most popular among the control strategies based on droop characteristics, in addition a central controller is described within a hierarchical control scheme to optimize the operation of the microgrid during interconnected operation. Microgrid control methods, including PQ control, droop control, voltage/frequency control, and current control methods are formulated.

Operation of Microgrid and Control Strategies

2022 ◽  
pp. 111-126
Author(s):  
Suma Deepthi Veeraganti ◽  
Ramchandra Nittala
Keyword(s):  
Electric Power ◽  
Rural Areas ◽  
Control Strategies ◽  
Electric Power Industry ◽  
Power Industry ◽  
Current Control ◽  
Frequency Regulation ◽  
Control Methods ◽  
Islanded Mode ◽  
And Control

Microgrids are the most innovative area in the electric power industry today. A microgrid can operate in grid-connected or islanded mode. In islanded mode, microgrids can provide electricity to the rural areas with lower cost and minimum power losses. Several methods have been proposed in the literature for the successful operation of a microgrid. This chapter presents an overview of the major challenges and their possible solutions for planning, operation, and control of islanded operation of a microgrid. Microgrids are the most innovative area in the electric power industry today. Moreover, microgrids provide local voltage and frequency regulation support and improve reliability and power capacity of the grid. The most popular among the control strategies based on droop characteristics, in addition a central controller is described within a hierarchical control scheme to optimize the operation of the microgrid during interconnected operation. Microgrid control methods, including PQ control, droop control, voltage/frequency control, and current control methods are formulated.

Reduction of Consumed Energy and Control Input Variance in Machine Tool Feed Drives by Contouring Control

2009 ◽  
Vol 3 (4) ◽  
pp. 401-407 ◽  
Author(s):  
Naoki Uchiyama ◽  
◽  
Takaya Nakamura ◽  
Kazuo Yamazaki ◽  
Keyword(s):  
Controller Design ◽  
Electricity Consumption ◽  
Contour Error ◽  
Control Input ◽  
Control Performance ◽  
Feed Drives ◽  
Controller Gain ◽  
Contouring Control ◽  
And Control ◽  
Better Than

Contouring control has been widely studied to reduce contour error, defined as error components orthogonal to desired contour curves. Its effectiveness has, however, to the best of our knowledge, only been verified through comparative experiments using industrial non-contouring (independent axial) controllers or conventional contouring controllers such as the cross-coupling controller. Because control performance depends largely on controller gain, these comparisons have problems in showing the effectiveness of contouring control, meaning that similar control performance could be attained if non-contouring controller gain were appropriately assigned. This paper presents contouring controller design for biaxial feed drives that reduces controller gain, rather than contour error, better than conventional independent axial controllers. The contouring controller is shown in experiments to effectively reduce control input variance and electricity consumption on average by 4.5%.

The Coordinated Control Strategies of Voltage Stability Based on Expert Rules

2013 ◽  
Vol 732-733 ◽  
pp. 772-777
Author(s):  
Fei Zhang ◽  
Chun Lin Guo ◽  
Ling Yun Jiang ◽  
Lin Yang ◽  
Jian Zhang
Keyword(s):  
Voltage Stability ◽  
Control Strategies ◽  
Coordinated Control ◽  
Control Methods ◽  
Stability Problems ◽  
Process Characteristics ◽  
Control Rules ◽  
Facts Devices ◽  
And Control ◽  
Better Than

According to the process characteristics and control methods of different voltage stability problems, the paper researches control rules and strategies of the voltage stability, then sets up controllers of FACTS devices on a simulation platform, and puts forward the coordinated control strategies of voltage stability problems based on expert rules. The simulation studies have shown that control effects of multiple FACTS devices are significantly better than a single device, and the coordinated control methods based on the expert rules is more conducive to improving voltage stability.

scholarly journals Combining Distributed Consensus with Robust H∞-Control for Satellite Formation Flying

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 319
Author(s):  
Julian Scharnagl ◽  
Florian Kempf ◽  
Klaus Schilling
Keyword(s):  
Distributed Control ◽  
Formation Control ◽  
Control Method ◽  
Special Focus ◽  
Control Methods ◽  
Consensus Approach ◽  
Distributed Consensus ◽  
Space Applications ◽  
Multi Agent ◽  
Common Goals

Control methods that guarantee stability in the presence of uncertainties are mandatory in space applications. Further, distributed control approaches are beneficial in terms of scalability and to achieve common goals, especially in multi-agent setups like formation control. This paper presents a combination of robust H ∞ control and distributed control using the consensus approach by deriving a distributed consensus-based generalized plant description that can be used in H ∞ synthesis. Special focus was set towards space applications, namely SFF. The presented results show the applicability of the developed distributed robust control method to a simple, though realistic space scenario, namely a spaceborne distributed telescope. By using this approach, an arbitrary number of satellites/agents can be controlled towards an arbitrary formation geometry. Because of the combination with robust H ∞ control, the presented method satisfies the high stability and robustness demands as found e.g., in space applications.

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