Current Issue : April - June Volume : 2016 Issue Number : 2 Articles : 6 Articles
A robust control approach is presented to study the problem of Q-S synchronization between Integer-order and fractionalorder\nchaotic systems with different dimensions. Based on Laplace transformation and stability theory of linear integer-order\ndynamical systems, a new control law is proposed to guarantee the Q-S synchronization between...
This paper presents a continuous-time adaptive control scheme for systems with uncertain nonsymmetrical\ndeadzone nonlinearity located at the output of a plant. An adaptive inverse function\nis developed and used in conjunction with a robust adaptive controller to reduce the effect of\ndeadzone nonlinearity. The deadzone inverse function is also implemented in continuous time,\nand an adaptive update law is designed to estimate the dead zone parameters. The adaptive output\ndead zone inverse controller is smoothly differentiable and is combined with a robust adaptive\nnonlinear controller to ensure robustness and boundedness of all the states of the system as well\nas the output signal. The mismatch between the ideal deadzone inverse function and our proposed\nimplantation is treated as a disturbance that can be upper bounded by a polynomial in the system\nstates. The overall stability of the closed-loop system is proven by using Lyapunov method, and\nsimulations confirm the efficacy of the control methodology....
The state observation problem is tackled for a system of ...
In a gas governor unit, gas pressure vibration often occurs in the tube that connects the diaphragm chamber of the pilot valve to the downstream pipeline. Generally, placing a restriction such as an orifice in the tube can curb the vibration. However, because of the nonlinear flow rate characteristics of an orifice, the gain of the pressure response changes with changing amplitude of the pressure vibration. This paper proposes a method that employs porous materials for improving the characteristics of the gas pressure control system on account of their linear flow rate characteristics. A static flow rate characteristics experiment was performed and the linear flow rate characteristics of the porous materials were confirmed. Then, a series of dynamic pressure response experiments, in which an isothermal chamber replaced the diaphragm chamber, were performed to examine the dynamic characteristics of the porous materials and an orifice. The experimental results revealed that the gain of the pressure response in the isothermal chamber with the porous materials remained unchanged irrespective of changes in the pressure vibration amplitude, and they were in close agreement with the simulation results. They also indicated that the pressure gain of porous materials is smaller than that of an orifice when the amplitude of pressure vibration is small. These results demonstrate that porous materials can be employed instead of an orifice in the gas governor unit in order to improve the unit�s stability....
Automatic aggressive maneuvers with quadcopters are regarded as a highly challenging control problem. The aim is to tackle the\nsingularities that exist in a vertical looping maneuver.Modeling singularities are resolved by writing the equations-of-motion of the\nquadcopter in quaternion form. Physical singularities due to underactuation are resolved by using an energy-based control. Energy based\ncontrol is utilized to overcome the uncontrollability of the quadcopter at physical singular configurations, for instance, when\ncommanding the quadcopter to gain altitude while pitched at 90âË?Ë?.Three looping strategies (circular, cloth oidal, and newly developed\nconstant thrust) are implemented on a nonlinear model of the quadcopter. The three looping strategies are discussed along with\ntheir advantages and limitations....
By data drift, we mean the data received by the controller may be different from that sent by the sensor, or the data received\nby actuator may be different from that sent by the controller.The issues of guaranteed cost control for a class of continuous-time\nnetworked control systems with data drift are investigated. Firstly,with the consideration of data drift between sensor and controller,\na closed-loop model of networked control systems including network factors such as time-delay and data-dropouts is established.\nAnd then, selecting an appropriate Lyapunov function, a guaranteed cost controller in terms of linear matrix inequality (LMI) is\ndesigned to asymptotically stabilize the networked control system with data drift. Finally, simulations are included to demonstrate\nthe theoretical results....
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