Current Issue : July - September Volume : 2017 Issue Number : 3 Articles : 5 Articles
In this paper, a new arc-surfaced frictional damper (AFD) is proposed and its hysteretic behavior is experimentally studied. Then\nthe device is applied to container crane based on a seesawmechanism.Themajor advantage of the seesawdamping systemis that the\nlong tension cables can be utilized as bracing between the seesawmember and the portal legs to avoid compression and buckling of\nthe cables. A simplified trilinear force-displacementmodel on the basis of experimental results is adopted to represent the hysteretic\nbehavior of AFD. After that, seismic responses of container crane with and without dampers to four earthquakes are studied using\nnonlinear dynamic time-history analysis. Besides this system, a diagonal-brace-AFD system is studied for comparison. A method\nbased on the displacement and energy dissipation ratio is proposed to find the optimum slip force for seesaw damping system.\nPerformance of AFD control system is assessed though various parameters including displacement and maximum portal frame\ndrift angle. Results prove a feasible application of AFD control system to absorb large amounts of seismic energy and significantly\nreduce the structural responses....
The fault tolerant control problem for a DC motor system is investigated in a cloud environment. Packet dropout phenomenon\nintroduced by the limited-capacity communication channel is considered. Actuator faults are taken into consideration and fault\ndiagnosis andfault tolerant controlmethods towards actuator faults areproposedtoenhance the reliability of thewhole cloud-based\nDC motor system. The fault diagnosis unit is then established with purpose of obtaining fault information.When the actuator fault\nis detected by comparing the residual signal with a predefined threshold, a residual matching approach is utilized to locate the fault.\nThe fault can be further estimated by a least-squares filter. Based on the fault estimation, a fault tolerant controller is designed to\nguarantee the stability as well as the control performance of the DC motor system. Simulation result on a DC motor system shows\nthe efficiency of the fault tolerant control method proposed in this paper....
The distributed control architecture becomes more and more important in future gas turbine engine control systems, in which the\nsensors and actuators will be connected to the controllers via a network. Therefore, the control problem of network-enabled highperformance\ndistributed engine control (DEC) has come to play an important role in modern gas turbine control systems, while,\ndue to the properties of the network, the packet dropouts must be considered. This study introduces a distributed control system\narchitecture based on a networked cascade control system (NCCS). Typical turboshaft engine distributed controllers are designed\nbased on the NCCS framework with...
In order to improve the performance of the hydraulic support electro-hydraulic control\nsystem test platform, a self-tuning proportion integration differentiation (PID) controller is proposed\nto imitate the actual pressure of the hydraulic support. To avoid the premature convergence and to\nimprove the convergence velocity for tuning PID parameters, the PID controller is optimized with\na hybrid optimization algorithm integrated with the particle swarm algorithm (PSO) and genetic\nalgorithm (GA). A selection probability and an adaptive cross probability are introduced into the\nPSO to enhance the diversity of particles. The proportional overflow valve is installed to control the\npressure of the pillar cylinder. The data of the control voltage of the proportional relief valve amplifier\nand pillar pressure are collected to acquire the system transfer function. Several simulations with\ndifferent methods are performed on the hydraulic cylinder pressure system. The results demonstrate\nthat the hybrid algorithm for a PID controller has comparatively better global search ability and\nfaster convergence velocity on the pressure control of the hydraulic cylinder. Finally, an experiment\nis conducted to verify the validity of the proposed method....
In this paper, a novel Model Reference Adaptive Control (MRAC)-based hybrid control\nalgorithm is presented for the trajectory tracking of a tri-rotor Unmanned Aerial Vehicle (UAV).\nThe mathematical model of the tri-rotor is based on the Newtonââ?¬â??Euler formula, whereas the\nMRAC-based hybrid controller consists of Fuzzy Proportional Integral Derivative (F-PID) and Fuzzy\nProportional Derivative (F-PD) controllers. MRAC is used as the main controller for the dynamics,\nwhile the parameters of the adaptive controller are fine-tuned by the F-PD controller for the altitude\ncontrol subsystem and the F-PID controller for the attitude control subsystem of the UAV. The stability\nof the system is ensured and proven by Lyapunov stability analysis. The proposed control algorithm\nis tested and verified using computer simulations for the trajectory tracking of the desired path\nas an input. The effectiveness of our proposed algorithm is compared with F-PID and the Fuzzy\nLogic Controller (FLC). Our proposed controller exhibits much less steady state error, quick error\nconvergence in the presence of disturbance or noise, and model uncertainties....
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