The wireless body sensor network (WBSN) technologies are one of the essential technologies of the Internet of things (IoT) growths of the healthcare paradigm, where every patient is monitored through a group of small-powered and lightweight sensor nodes. Thus, energy consumption is a major issue in WBSN. The major causes of energy wastage in WBSN are collisions and retransmission process. However, the major cause of the collision happened when two sensors are attempting to transmit data at exactly the same time and same frequency, and the major cause of the retransmission process happened when the collision takes place or data does not received properly due to channel fading. In this paper, we proposed a cognitive cooperative communication with two master nodes, namely, as two cognitive master nodes (TCMN), which can eliminate the collision and reduce the retransmission process. First, a complete study of a scheme is investigated in terms of network architecture. Second, a mathematical model of the link and outage probability of the proposed protocol are derived. Third, the end-to-end delay, throughput, and energy consumption are analyzed and investigated. The simulation and numerical results show that the TCMN can do system performance under general conditions with respect to direct transmission mode (DTM) and existing work.

Torque Sharing Function (TSF) approach can be considered a promising method to solve the torque ripple issue in switched reluctance motors (SRMs) drives at low and medium speed ranges. However, at the high-speed operation of the machine, the actual phase current fails to track the reference current profile. This limitation primarily occurs over the demagnetization period of each phase current. Consequently, each phase torque will also fail to track its corresponding reference torque created by the TSF strategy. As a result, of the torque tracking error, a considerable torque ripple will be produced. To address this issue, a novel hybrid TSF is proposed in this research article. The hybrid TSF can adapt during the real-time operation relying on the current (and thus the torque) tracking capability during the magnetization period, which is much higher than during the demagnetization period. At each electrical cycle, the rising part of the incoming phase torque reference is re-profiled to mirror the declining part of the actual torque of the outgoing phases. And therefore, the torque tracking error can be compensated, and a remarkable torque ripple suppression will be attained. Additionally, within the hybrid TSF, an overlap angle controller is also proposed in this work and participated in high-speed operation. The controller keeps monitoring the error between the commanded torque and the actual average torque of the machine, and by adjusting the overlap angle in real-time, the error can be further compensated. Thus, further torque tracking capability is attained. A set of simulation results are presented and favorably compared with other traditional TSF approaches to demonstrate the feasibility and validity of the proposed hybrid TSF.

Torque sharing function (TSF) is an efficient torque ripple minimization approach in switched reluctance motor (SRM) drives in low and medium speed ranges. In this paper an optimized TSF is presented to enhance the torque profile of SRM over an extended speed range while maintaining an acceptable value of the average output torque. A secondary objective is to minimize the RMS phase current also included in the optimization problem. The control variables are the switch-on angle and the overlap angle. An improved version of the ant colony optimization (ACO) based procedure is employed in this work. Additionally, a highly trusted SRM model is built using finite element method (FEM), this model is then adopted by the optimizer to accurately select the optimal values of the control variables. Simulation is carried out on 4 kW, 1500 rpm, four-phase 8/6 SRM.

Due to their advantages, switched reluctance motors (SRMs) are interesting solutions for electric vehicle (EV) propulsion. However, they have the main drawback of high torque ripple. This paper develops a universal torque control (UTC) technique for SRM that can fulfill all vehicle requirements under a wide range of speeds. The developed UTC involves two different control techniques. It utilizes the direct instantaneous torque control (DITC) strategy in a low speed region, and the average torque control (ATC) strategy in high speeds. The selection of DITC and ATC is made based on their performance regarding torque ripple, torque/current ratio, and efficiency. Moreover, a novel transition control between the two control techniques is introduced. The results show the ability of the proposed UTC to achieve vehicle requirements while obtaining all the benefits of torque control over the possible range of speeds. The proposed UTC provides the best performance regarding minimum torque ripple, maximum torque/current ratio, and maximum efficiency over the whole speed range. The transition control achieves a smooth operation without any disturbances. The transition control helps to simplify the overall control algorithm, aiming to have a feasible and practical UTC without a complicated control structure.