By using the hierarchical controller approach, a new solution for the control problem related to trajectory tracking in a differential drive wheeled mobile robot (DDWMR) is presented in this paper. For this aim, the dynamics of the three subsystems composing a DDWMR, i.e., the mechanical structure (differential drive type), the actuators (DC motors), and the power stage (DC/DC Buck power converters), are taken into account. The proposed hierarchical switched controller has three levels: the high level corresponds to a kinematic control for the mechanical structure; the medium level includes two controls based on differential flatness for the actuators; and the low level is linked to two cascade switched controls based on sliding modes and PI control for the power stage. The hierarchical switched controller was experimentally implemented on a DDWMR prototype via MATLAB-Simulink along with a DS1104 board. With the intention of assessing the performance of the switched controller, experimental results associated with a hierarchical average controller recently reported in literature are also presented here. The experimental results show the robustness of both controllers when parametric uncertainties are applied. However, the performance achieved with the switched controller introduced in the present paper is better than, or at least similar to, performance achieved with the average controller reported in literature.

A sensorless control based on the exact tracking error dynamics passive output feedback (ETEDPOF) methodology is proposed for executing the angular velocity trajectory tracking task on the “full-bridge Buck inverter–DC motor” system. When such a methodology is applied to the system, the tracking task is achieved by considering only the current sensing and by using some reference trajectories for the system. The reference trajectories are obtained by exploiting the flatness property associated with the mathematical model of the “full-bridge Buck inverter–DC motor” system. Experimental tests are developed for different desired angular velocity trajectories. With the aim of obtaining the experimental results in closed-loop, a “full-bridge Buck inverter–DC motor” prototype, Matlab-Simulink, and a DS1104 board from dSPACE are employed. The experimental results show the effectiveness of the proposed control.

This work addresses the control problem related to the bidirectional velocity of a DC motor feeded by a DC/DC Buck converter–inverter as power amplifier. While various power electronic topologies have been proposed in literature, this research focuses on one that was previously disregarded due to its delivery of pulse width modulated voltage signals instead of smooth voltage signals to the DC motor. However, in the present paper it is demonstrated that by appropriately controlling the power electronic converter it is indeed possible to deliver the desired smooth voltage signals to the motor. Moreover, the proposed control strategy is robust, employing multiple proportional-integral loops, and a sliding mode controller. A formal proof of asymptotic stability is provided and the robustness is verified through experimental validation.

By designing a robust control, for the first time in literature, the tracking task associated with the MIMO DC/DC Boost converter-inverter-DC motor system is solved. Such robustness is achieved through the exploitation of the differential flatness property related to the system and by a suitable design of auxiliary controls. With the aim of verifying the performance of the robust control, a platform of the system along with MATLAB-Simulink and a DS1104 board are used. The experimental results show the good performance of the system in closed-loop even when electrical abrupt changes are considered in some parameters of the Boost converter and when a mechanical load perturbation is applied.

Quantum entanglement lies at the heart of quantum information and quantum metrology. In quantum metrology, with a colossal amount of quantum Fisher information (QFI), entangled systems can be ameliorated to be a better resource scheme. However, noisy channels affect the QFI substantially. This research work seeks to investigate how QFI of N-qubit Greenberger-Horne-Zeilinger (GHZ) state is affected when subjected to decoherence channels: bit-phase flip (BPF) and generalize amplitude damping (GAD) channels, which can be induced experimentally. We determine the evolution under these channels, deduce the eigenvalues, and then derive the QFI. We found that when there is no interaction with the environment, the Heisenberg limit can be achieved via rotations along the z direction. It has been shown that in BPF channel, the maximal mean QFI of the N-qubit GHZ state ( $${\bar{F}}_{max}$$F ¯ m a x ) dwindles as decoherence rate (p _B ) increases due to flow of information from the system to the environment, until p _B = 0.5, then revives to form a symmetric around p _B = 0.5. Thus, p _B > 0.5 leads to a situation where more noise yields more efficiency. We found that in GAD channel, at finite temperature, QFIs decay more rapidly than at zero temperature. Our results also reveal that QFI can be enhanced by adjusting the temperature of the environment.