A Hybrid Control Study of Bearingless Induction Motor

The bearingless motor combined technical characteristics of motor and magnetic bearings. It can simultaneously implemented electromagnet torque control and suspension control all in the motor .Since there are two sets of windings wound on the stator of bearingless motor, two sets of power circuit hardware and controller are required. In the case of most conventional structures, each terminal controller calculate references by themselves and transmits a torque/positon interactively. However, the latency issues of data delivery latency affecting the decoupling between the air-gap flux.The paper proposed the structure for a torque/positon hybrid control through network, torque/positon is transmitted from each terminal controller to a central controller. Then the central controller calculates references that are feedback to the terminal. The delay time is eliminated. In the paper, the hybrid control of bearingless induction motor is realized with the digital system based on the TMS320F2812.

A Survey on Mobility-Assisted Data Collection in Wireless Sensor Networks

Collecting data from spatially distributed sensor nodes is a generic form of sensor network applications. Multihop forwarding has been broadly used for this purpose, but it could be inefficient in terms of energy consumption.A downside of this approach is an increased data delivery latency, and thus we should optimize the motion of data mule so that we can minimize the latency. In this paper, we survey the existing work on the mobility-assisted data collection by classifying them into three categories based on the mobility exploited: the random mobility, the predictable mobility, and the controlled mobility. We also highlight several open problems on this topic.