Joint torque control of a robotic manipulator requires a close dynamic description model involving the non negligible dynamics of the subsystems making up the system. The mathematical model for joint torque control of the robotic manipulator has been identified as one of the major sources of failures of commercial robots. The manipulator is basically made up of links connected by joints, and the torque that moves the links connected to a joint is produced by the joint actuator and also in practice, the control law is fed into the actuator inputs, therefore the actuator dynamics becomes non negligible dynamics in the dynamic modeling of the manipulator for robust joint torque control. Hence, a complete dynamic model of the manipulator which involves the link dynamics plus actuator dynamics was proposed. This paper focuses on the modeling of a 3DOF articulated manipulator based on independent joint (decentralized) scheme and the determination of the viscous damping coefficient for the joint torque control model. The independent joint model provides closer mathematical description of the manipulator and also enhances robust controller design. Joint damping coefficient B, was determined through experiment based on bode plot of the open loop gain. From the results, it was concluded that joints I and II achieved the best performance when B is 0.001N.m/rad /sec and 0.01N.m/rad /sec respectively.

With the astronomical growth in online presence vis-à-vis the IT industry across the globe, there is an urgent need to evolve cloud based DataCenter architectures that can rapidly accommodate web application integrations which can serve the energy industries, educational sector, finance sector, manufacturing sector, etc. Previous works in DataCenter domain have not investigated on cloud based DataCenter Servercentric characteristics for evaluation studies. This paper then proposed a Reengineered DataCenter (R-DCN) architecture for efficient web application integration. In this regard, attempt was made to address network scalability, efficient and distributed routing, packets traffic control, and network security using analytical formulations and behavioural algorithms having considered some selected architectures. In this work, a simulation experiment was carried out to study six key performance metrics for all the architectures. It was observed that the network throughput, fault-tolerance/network capacity, utilization, latency, service availability, scalability and clustering effects of R-DCN responses with respect to above Key Performance (KPIs) metrics were satisfactory when compared with BCube and DCell architectures. Future work will show a detailed validation using a cloud testbed and CloudSim Simulator.

This research work emphasizes on design of a robust control for a 3DOF robotic manipulator under uncertainties. The plant model was achieved using the independent joint method and the uncertainty problem was addressed by designing a robust controller using H-Infinity synthesis which was compared with PID. This was achieved with algorithms implemented in MATLAB. The H-Infinity controller recorded 0dB, while PID controller recorded 0.117dB and 0.061dB for joints I and II respectively in Complementary Sensitivity (T) graph at low frequencies. H-Infinity controller achieved better disturbance rejection characteristics with sensitivity (S) graph recording peak sensitivity of 0.817dB and 1.79dB at joints I and II respectively than PID controller which achieved 3dB and 1.86dB at joints I and II respectively. H-Infinity controller achieved better noise rejection characteristics with T graph recording lower gains at joints I and II respectively at high frequencies than PID controller which recorded higher gains at joints I and II respectively. Thus, it was concluded that the H-Infinity controller achieved better performance and stability robustness characteristics for the joint torque control than the PID.

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Abstract-The energy demand in the enterprise market segment demands a supply format that accommodates all generation and storage options with active participation by end users in demand response. Basically, with today's high power computing (HPC), a highly reliable, scalable, and cost effective energy solution that will satisfy power demands and improve environmental sustainability will have a broad acceptance. In a typical enterprise data center, power managment is a major challenge impacting server density and the total cost of ownership (COO). Storage uses a significant fraction of the power budget and there are no widely deployed power-saving solutions for enterprise storage systems. This work presents Data Center Networks (DCNs) for efficient power management in the context of SMART Grids. A SMART DCN is modelled with OPNET 14.5 for Network, Process and Node models. Also, an Extended SMART Integration Module in the context of SMART DCN is shown to be more cost effective than the traditional distribution grid in DCNs. The implementation challenges are discussed also. This paper suggests that smartening the grid for DCN will guarantee a sustainable energy future for the enterprise segments.