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An efficient monitoring and control system for solar photovoltaic modules, which combines the use of a non-linear MPPT backstepping controller with a custom wireless sensor network (WSN) has been developed. The infrastructure consists of a wireless smart photovoltaic system (WSPS) and a wireless centralized control system (WCC). The data of sensing, coordination and control is handled by using a WSN based on IEEE 802.15.4 technology in beacon enable mode and with guaranteed time slot. This assures the data transmission and a synchronous acquisition, which are critical elements in a wireless photovoltaic monitoring system. All measured data is gathered by an autonomous, compact and low-cost sensor node installed in each PV module, and it is transferred to the coordinator node. The power consumption of the sensor node represents only 0.25% of the power delivered by the photovoltaic module. A backstepping controller to track the Maximum Power Point (MPP) by means of a buck-boost converter derives the reference parameters to return to each PV module accordingly. The wireless solution uses low latency techniques to achieve a real-time monitoring and a stable performance of the controller. The centralized control identifies all the network nodes and significantly simplifies the maintenance operations. Experimental validation shows the robustness against interference and security in the wireless data transmission and confirms the feasibility of the proposed wireless sensor system in tracking the maximum power transfer under different weather conditions, achieving an efficiency over the 99% in the MPPT.

The design, monitoring, and control of photovoltaic (PV) systems are complex tasks that are often handled together, and they are made even more difficult by introducing features such as real-time, sensor-based operation, wireless communication, and multiple sensor nodes. This paper proposes an integrated approach to handle these tasks, in order to achieve a system efficient in tracking the maximum power and injecting the energy from the PV modules to the grid in the correct way. Control is performed by means of an adaptive Lyapunov maximum power point tracking (MPPT) algorithm for the DC/DC converters and a proportional integral (PI) control for the inverters, which are applied to the system using low latency wireless technology. The system solution exploits a low-cost wireless multi-sensor architecture installed in each DC/DC converter and in each inverter and equipped with voltage, current, irradiance, and temperature sensors. A host node provides effective control, management, and coordination of two relatively independent wireless sensor systems. Experimental validation shows that the controllers ensure maximum power transfer to the grid, injecting low harmonic distortion current, thus guaranteeing the robustness and stability of the system. The results verified that the MPPT efficiency is over 99%, even under perturbations and using wireless communication. Moreover, the converters’ efficiency remains high, i.e., for the DC/DC converter a mean value of 95.5% and for the inverter 93.3%.

This paper presents a new mechanism for the management of mobile nodes fully compatible with IEEE 802.15.4 standard in non-beacon enabled mode. The proposed solution overcomes the problem related to the high association time of mobile nodes in this standard where continuous associations affect the activity time. A static structure supports the mobile nodes, and the procedure allows both data transmission from a mobile node and data reception from the static nodes with minimal activity time and high communication reliability. The approach reduces power consumption and packet loss. Experimental results have been measured on a network composed by a static structure of various hierarchical levels with multiple mobile nodes moving freely, and confirm the suitability of the proposed low activity mechanism.

This paper presents a wireless fault detection system for industrial motors that combines vibration, motor current and temperature analysis, thus improving the detection of mechanical faults. The design also considers the time of detection and further possible actions, which are also important for the early detection of possible malfunctions, and thus for avoiding irreversible damage to the motor. The remote motor condition monitoring is implemented through a wireless sensor network (WSN) based on the IEEE 802.15.4 standard. The deployed network uses the beacon-enabled mode to synchronize several sensor nodes with the coordinator node, and the guaranteed time slot mechanism provides data monitoring with a predetermined latency. A graphic user interface offers remote access to motor conditions and real-time monitoring of several parameters. The developed wireless sensor node exhibits very low power consumption since it has been optimized both in terms of hardware and software. The result is a low cost, highly reliable and compact design, achieving a high degree of autonomy of more than two years with just one 3.3 V/2600 mAh battery. Laboratory and field tests confirm the feasibility of the wireless system.

This paper presents a study about hardware attacking and clock signal vulnerability. It considers a particular type of attack on the clock signal in the I2C protocol, and proposes the design of a new sensor for detecting and defending against this type of perturbation. The analysis of the attack and the defense is validated by means of a configurable experimental platform that emulates a differential drive robot. A set of experimental results confirm the interest of the studied vulnerabilities and the efficiency of the proposed sensor in defending against this type of situation.

This paper presents a study on various types of attacks on the security of a robotic system. The work focuses on hardware attacks, and particularly considers vulnerable features of the I2C protocol. An analysis of the effects of these attacks, when they are applied on a differential driving mobile robot that aims to track a path, is presented. The paper shows how, with such actions, it is possible to modify the behavior of the robot without leaving traces of the attack and also maintaining the system without any damage.