International Journal of System Control and Information Processing (7 papers in press)
Cross-layer Transmission Design in a Class of Delay-Aware Two-User Interference Networks
by Muhu Li, Ping Wang, Chao Wang, Fuqiang Liu, Yusheng Ji
Abstract: This paper investigates the transmission design problem in a class of two-user interference networks where each source sends two types of delay-sensitive message to its destination. The first type is generated periodically with fixed rate and is desired to be delivered immediately with sufficiently high reliability. The second type, generated randomly, can be placed in queues but the average queueing delay should be finite. Each user applies point-to-point Gaussian random codes to transmit information, using constrained instantaneous and average powers. We utilize the Lyapunov optimization theory to construct a cross-layer transmission strategy, which can adapt to both the channel state information (CSI) at the physical layer and the queue state information at the media access control layer. Our results show that the proposed strategy can achieve a better tradeoff among power consumption, transmission reliability, and queueing delay, compared with the conventional CSI-based transmission design.
Keywords: Wireless interference networks; cross-layer transmission design; power allocation; Lyapunov optimization.
Application of Multi-objective Mathematical Programming Technique for Contractor Selection
by Srikumar Acharya, Ankita Nanda
Abstract: In this paper, a multi-objective mathematical model is formulated for contractor selection problem, which is solved taking into consideration various attributes for supplying goods for a University mess in the hostel. For better mathematical model formulation factors like, past performance, financial status, product return policy, time factors etc. of contractors are considered. In order to illustrate the methodology a case 0f one University is considered. A mathematical model is also formulated by considering the data of the mess of the University. Finally, it is solved to select appropriate contractors using fuzzy programming method.
Keywords: Fuzzy Programming Method; Contractor Selection; Multi-Objective Programming Problem.
Nonlinear power control of Variable Speed Wind Turbines above rated wind speed
by Miaomiao Ma
Abstract: This paper proposes a triple-step nonlinear control scheme for variable speed wind turbines above the rated wind speed to maintain the output power at the rated value. The controller design procedure is divided into three parts: steady-state-like control; feedforward control based on reference dynamics; and state dependent feedback control. The gains of controller are state-dependent and parameter-varying. The simulation results for a NREL-offshore-baseline 5 MW wind turbine system show the efficiency of the proposed nonlinear controller.
Keywords: Variable speed wind turbine; pitch control; nonlinear control; rated power.
Finite-time Control for Fuzzy Networked Systems with State Delay and Network-induced Delay
by Hejun Yao
Abstract: To investigate the finite-time stabilization control problem for a class of nonlinear networked systems, a T-S fuzzy model is employed to represent the nonlinear controlled plant with state delay and time varying network induced delay. Based on the Lyapunov stability theory and linear matrix inequality approach, a finite-time stabilization sufficient condition is obtained. Then, a state feedback fuzzy controller which can make the network systems finite-time stable is designed. Finally, a numerical example is given to demonstrate the application and effectiveness of the proposed method.
Keywords: Networked control systems; T-S model; Stochastic delays; Linear matrix inequality.
Networked Mobile Robot Leader-Follower Trajectory Tracking Control with delays
by Jian Feng, Xiang Qiu, WenAn Zhang
Abstract: We consider the leader-follower trajectory tracking control problem for networked mobile robots. The leader and follower communicate with each via communication network and the network-induced delays are considered. Firstly, an uncertain system model is presented to describe the leader-follower trajectory tracking control system with delays, where the dynamics induced by the uncertain part of the delay is described by the model uncertainties. Secondly, an extended state observer (ESO) is designed to estimate the uncertainty of the trajectory tracking control system, and then the uncertainties induced by the delays are compensated by the ESO using dynamic linearization compensation. In this way, the effects of the network induced delays are removed and the linear active disturbance rejection control (LADRC) method is thus implemented to achieve the objective of high performance trajectory tracking control. Finally, an illustrative example is presented to show the effectiveness and superiority of the proposed method.
Keywords: mobile robot; trajectory tracking; networked systems; delay; linear active disturbance rejection control.
SEMG-Based Research of Upper Body Muscle Fatigue during Manual Material Handling
by Na Yu
Abstract: The upper body muscles frequently contract during manual material handling tasks, and muscle fatigue could arise during the repetitive contraction. To explore the muscle fatigue within arm, shoulder and back during material handling, 11 male graduate students were chosen as subjects to simulate furniture boards handling task. In the experiment, the vertical lifting distance, set 3 levels, was the single test variable. Through analyzing normalized average electromyography (Normalized AEMG) and mean power frequency (MPF) of the electromyography signal collected during the experiment, found that the biceps brachii muscle the most relaxed, and the multifidus muscle the most fatigable. In order to reduce waist muscle load , it is suggest that operators increase their use of arm strength during material handling, optimizing work posture.
Keywords: Muscle fatigue; Material handling; sEMG; work posture.
Design of Neural Network based MRAC
by Dixit Sethi, Swati Sharma, Jagdish Kumar, Rintu Khanna
Abstract: Journal presents the comparison of Conventional-MRAC (Model Reference Adaptive Controller), Advanced-MRAC and Neural Network based MRAC (NN-MRAC) scheme. The MIT Rule and Lyapunov Rule are used for the design of controller parameter adaptation laws. The main research is on how to adapt the control actions more effectively to solve the problem of disturbances and non-linearities. Conventional-MRAC alone is unable to handle nonlinearities and disturbances of the plant and to provide a stable and controlled output, we augment an NN controller, in parallel with MRAC controller, to compensate the nonlinearities and disturbances present in the plant and this scheme is called as NN-MRAC scheme. All methods are applied with analytical detail to a chosen (SISO) second-order inherently unstable system named Inverted Pendulum with the application of some uncertainties and disturbances. It is clearly seen from the computer simulation results that NN-MRAC system improves the performance of the system effectively.
Keywords: Model Reference Adaptive Controller (MRAC); Advanced-MRAC(AMRAC); Neural Network based MRAC(NN-MRAC); MIT Rule; Lyapunov Rule; and PID; Multilayer Backpropagation Neural Network (MBPNN).