Wireless sensor networks (WSNs) have been widely applied in industrial applications especially since the release of IEEE 802.15.4 standard. By participating in an automobile project in which an IEEE 802.15.4 based sensor and actuator network is deployed to measure and control the vibrations of an automotive system, we need to study many metrics of IEEE 802.15.4 sensor networks (e.g., packet delivery rate,latency and energy consumption) under various sampling rates. In order to provide detailed modeling of hardware and software as well as network behaviors on each sensor node, we conduct plenty of experiments on a SystemC-based WSN simulator IDEA1 which supports the hardware and software co-simulation of sensor nodes with certain flexibility of abstraction level. Compared with the existing works on performance evaluation of IEEE 802.15.4 protocols, the main contributions of this paper are the comprehensive studies of both beacon-enabled and nonbeacon-enabled modes under various parameter settings and the beacon tracking synchronization mechanism in the IEEE 802.15.4 standard which is ignored in most previous works. Additionally, the in-depth analysis of simulation results enables us to find the best parameter configurations to different traffic loads and application requirements which can be used as general experiences for other applications. Prepared using dacauth.cls [Version: 2010/03/27 v2.00] 2 W. DU, ET AL.which is a more powerful node in charge of collecting the sensor data from all nodes. Based on the analysis of collected data, some control actions are executed by the actuator network.In this industrial application, some preliminary designs based on the existing node hardware platforms and network protocols shall be evaluated at first. We need to study many metrics of this sensor network (e.g., packet delivery rate and latency) under various sampling rates and consider the power consumption of sensor nodes since they are wireless communication modules with small size to minimize the impact of measurement hardware on original automobile system. Wireless sensor networks (WSNs) have been widely used in industrial automations [2] since the IEEE 802.15.4 standard has been released [3]. In this paper, we evaluate the performance of IEEE 802.15.4 protocols based on MICAz motes [4] through simulation since it is the most direct and efficient method to perform this study compared with mathematical analysis or experimental testbeds.Many general-purpose network simulators like NS-2 [5] and OMNeT++ [6] have been used in WSN simulations. For example, a Petri-net based simulation model of a wireless mobile ad hoc network is developed in [7]. The simulation model was implemented in terms of a class of extended Petri nets to explicitly represent parallelism of events and processes in the WLAN as a distributed system. Generally, the network simulators have the advantages of extensibility, heterogeneity support and easy-to-use. However, the energy consumption estimation is usually based on some simple assumptions, for examp...

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This article presents IDEA1, a SystemC-based system-level design and simulation framework for WSNs. It allows the performance evaluation (e.g., packet delivery rate, transmission latency and energy consumption) at high level, but with elaborate models of the hardware and software of sensor nodes. Many hardware components are modeled and the IEEE 802.15.4 standard is implemented. IDEA1 uses a clock-based synchronization mechanism to support simulations with cycle accurate communication and approximate time computation. The simulation results have been validated by a testbed of 9 nodes. The average deviation between the IDEA1 simulations and experimental measurements is 4.6%. The performances of IDEA1 have also been compared with NS-2. To provide a similar result (deviation less than 5%) at the same abstraction level, the simulation of IDEA1 is 2 times faster than NS-2. Moreover, with the hardware and software co-simulation feature, IDEA1 provides more detailed modeling of sensor nodes. Finally, IDEA1 is used to study a real-time industrial application in which a wireless sensor and actuator network is deployed on a vehicle to measure and control vibrations. By the simulation, some preliminary designs based on IEEE 802.15.4 protocols and two different hardware platforms are evaluated.

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Many limitations (e.g. complexity, cost, scalability and capability) make the analytical methods and physical testbeds improper to evaluate the performances of wireless sensor networks (WSNs). Simulations can provide a good approximation at lower cost and in less time. Hence, a number of simulation tools for WSN have been developed in the past few years. However, different tools may emphasize on different features. For example, besides the general network simulators, some SystemC-based simulators have been developed recently in order to realize the hardware/software (HW/SW) co-design of the node at the system-level that also takes into account its network performances. So it is necessary to study the existing WSN simulators and to distinguish their different features. In this paper, we propose a taxonomy that categorizes the existing simulation tools into four classes according to their modeling methodologies and their target applications. In order to prove that the proposed taxonomy is reasonable and comprehensive, we use it to make a survey of the existing simulation tools. This study is intended to be broad enough to cover all the important existing simulation tools. The goal of this paper is to analyze the WSN simulation tools and help the WSN designers find an appropriate simulator.

Induction motors (IM) have been a fundamental part of industrial applications for over a century and the number of their applications continues to expand. A significant amount of the world’s total energy expense is consumed by this kind of motor. Hence, it is very important to increase the energy efficiency of these machines. Due to its good performance, field-oriented control (FOC) is the most common strategy to control IM. FOC requires references for stator current and rotor magnetic fluxes. For velocity regulation, a velocity reference is used instead of a stator current reference. However, at motor start-up or when a change of torque is required, it would be convenient for these references to be variable in order to reduce energy consumption. In this work, it is shown that this is indeed the case, and a technique to find optimal time-variable references for stator currents and magnetic rotor fluxes to reduce energy consumption is proposed. It is shown that, depending on the mechanical load, an energy reduction of 20–45% can be achieved.