This paper discusses the control of the compensation voltages in dynamic voltage restorers (DVR). On analyzing the power circuit of a DVR system, control limitations and control targets are presented for the compensat...
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This paper discusses the control of the compensation voltages in dynamic voltage restorers (DVR). On analyzing the power circuit of a DVR system, control limitations and control targets are presented for the compensation voltage control. Based on the preceded power stage analysis, a novel controller for the compensation voltages in DVRs is proposed by a feedforward control scheme. This paper also discusses the time delay problems in the control system of DVRs. Digital control systems inevitably have control delay due to its the sampling of signal, the switching frequency of an inverter, and the signal delay due to sensor itself. The total signal delay is considerable in real implementation and it endanger the system stability. This paper analyzes the relationship among the control delay, closed loop damping factor, and the output filter parameters of DVR inverters. Based on the control system analysis, a guideline is proposed to design the appropriate output filter parameters and the inverter switching frequency for DVRs. The proposed theory is verified by an experimental DVR system, which is controlled in full digital manner.
Nowadays having the most energy efficiency is desirable in its own right from both economical and environmental points of *** power management is a system level solution for reducing the consumed energy with putting o...
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Nowadays having the most energy efficiency is desirable in its own right from both economical and environmental points of *** power management is a system level solution for reducing the consumed energy with putting off unused parts of the system and putting them on in an efficient *** Emotional Learning Algorithm has been introduced to show the effect of emotions as well known stimuli in the quick and almost satisfying decision making in *** remarkable properties of emotional learning,low computational complexity and fast training,and its simplicity in multi objective problems has made it a powerful methodology in real time control and decision systems,where the gradient based methods and evolutionary algorithms are hard to be used due to their high computational *** the emotional approach has been successfully used to obtain multiple objectives in prediction problems of real world *** first we introduce methods of dynamic power management and then a new method based on BELBIC would be *** simulation results show that this method has a high efficiency in various systems.
Achieving energy-efficient dynamic walking has become one of the main subjects of research on robotic bipedal locomotion. Approaches based on passive-dynamic walkers can accomplish bipedal locomotion. However, passive...
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Achieving energy-efficient dynamic walking has become one of the main subjects of research on robotic bipedal locomotion. Approaches based on passive-dynamic walkers can accomplish bipedal locomotion. However, passive dynamic walking has only been studied with the legs, and the effect of an upper body has not been clarified. This paper investigates the effect of an upper body on the efficiency and stability of dynamic bipedal locomotion based on observations. We first investigated a suitable upper body, which was a simple 1-link torso with a bisecting hip mechanism that would not destroy natural dynamics of the biped model. Second, we analyzed the robot's driving mechanism and chose underactuated virtual passive dynamic walking as the method for generating an efficient dynamic gait. We confirmed that efficient dynamic walking was possible with a specific resistance of 0.01 and investigated the effect of the physical parameters of the upper body through numerical simulations.
A new parallel grasper mechanism having 3-DOF spherical motions is proposed. The mechanism consists of one parallel four-bar chain and four serial sub-chains that are connected in parallel to the four-bar chain. Parti...
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A new parallel grasper mechanism having 3-DOF spherical motions is proposed. The mechanism consists of one parallel four-bar chain and four serial sub-chains that are connected in parallel to the four-bar chain. Particularly, all joint axes of the mechanism are placed to have a common intersection point securing that all joint motion spaces of the mechanism are confined within the 3-DOF spherical motion spaces. Thus, the mechanism can not only grasp irregular shaped objects by changing configuration of its four-bar chain, but also exhibit 3 DOF spherical motions after grasping. The position analysis and kinematic analysis of the mechanism are performed. Also, its kinematic characteristics are investigated through simulation in aspects of three kinematic design indices. Lastly, a prototype was developed and tested through motion tracking and grasping experiments.
The complex ocean environment leads to low contrast in underwater images and poor target visibility. In addition, the detected objects have multi-scale properties and clustering issues, making marine object detection ...
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In order to improve the speed tracking control performance of Permanent magnet synchronous motors (PMSM) with uncertainties and disturbances, an uncertainty and disturbance estimator (UDE)-based PID-type sliding mode ...
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In order to improve the speed tracking control performance of Permanent magnet synchronous motors (PMSM) with uncertainties and disturbances, an uncertainty and disturbance estimator (UDE)-based PID-type sliding mode control (SMC) approach is proposed. The proposed controller consists of two parts, the reference model, and the UDE-based sliding mode controller. The reference signals of the actual system are generated by a reference model, whose controller is designed by using a nonsingular terminal sliding mode control (NTSMC), and then employed in the UDE-based controller design. The UDE is used to estimate the uncertainties and disturbances of the system, and an UDE-based SMC algorithm is then developed. It can be proved that the resulting closed-loop system is ultimately bounded. Finally, simulation results are given to illustrate that the proposed control scheme achieves good dynamic performance and strong robustness.
Dynamic voltage restorer (DVR)s are known as effective and economic means to compensate for voltage sags and swells. This paper proposes a novel method to generate reference waves synchronized with the grid whether or...
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Dynamic voltage restorer (DVR)s are known as effective and economic means to compensate for voltage sags and swells. This paper proposes a novel method to generate reference waves synchronized with the grid whether or not the line voltages are distorted by a fault. The proposed reference wave generator (RWG) looks for the normal voltage waveforms in the grid from the corrupted line voltages and synthesizes the expected positive sequence reference waves for DVRs. There is no transient problem on the generated reference waves when the line voltages are distorted by faults. Experimental results verified the proposed theory very well.
This paper studies the resilient consensus problem with time-varying adversary attacks and asynchronous events. In the synchronous or asynchronous update case, all the nodes or only a fraction of nodes update their st...
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ISBN:
(数字)9781728113982
ISBN:
(纸本)9781728113999
This paper studies the resilient consensus problem with time-varying adversary attacks and asynchronous events. In the synchronous or asynchronous update case, all the nodes or only a fraction of nodes update their states at each time step, respectively. For the synchronous update case, the nodes under attack are time-varying but do not change after some finite time;for the asynchronous update case, the nodes under attack are time-invariant. For both cases, a resilient consensus can be reached exponentially fast under a network topology condition inspired by the notion of the scrambling matrix and an explicit expression for the convergence rate is provided. Numerical examples are given to validate the theoretical results and to compare the performance with an existing algorithm.
The interactive evolutionary multi-task optimization approach assisted by surrogate models has proven successful in enhancing individualized recommendation performance. However, in light of the dynamically changing us...
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ISBN:
(数字)9798350308365
ISBN:
(纸本)9798350308372
The interactive evolutionary multi-task optimization approach assisted by surrogate models has proven successful in enhancing individualized recommendation performance. However, in light of the dynamically changing user preferences, it becomes imperative to further develop more powerful knowledge sharing strategy to improve the interactive multi-task optimization efficiency. A probability model-assisted search space alignment among multiple tasks method is proposed for knowledge transfer across multi-task environment. Additionally, a diversity maintaining mechanism of the transferred population is proposed to improve the quality and diversity of the initial population in a preference varied multi-task environment. The research demonstrates the effectiveness of the proposed approach in achieving effective knowledge transfer across multi-task environmen. Furthermore, the utilization of a high-quality initial population not only enhances the evolutionary search efficiency of the algorithm but also significantly improves the accuracy, diversity., and novelty of personalized recommendation.
The real-time map plays a vital role in the Internet of Vehicles (IoV) navigation. Compared with the existing map review, the real-time map review method is based on crowdsensing enabling faster data updates and short...
The real-time map plays a vital role in the Internet of Vehicles (IoV) navigation. Compared with the existing map review, the real-time map review method is based on crowdsensing enabling faster data updates and shortening the map period from map collection to service. However, the crowdsensing method requires frequent interaction between the vehicle and nearby devices or servers, increasing the risk of user privacy leakage. How to ensure the privacy of users is a challenge in the real-time map review. Starting from the typical architecture of IoV and combining the core idea of zero-trust “never trust, continuous verification”, IoV-ZT conceptual model architecture is designed. This paper proposes a based on linkable ring signature map review scheme for zero-trust autonomous vehicles (LRSMR). In the LRSMR, a linkable ring signature based on the SM2 digital signature algorithm is used to protect user identity privacy and ensures while ensuring signature linkability by hiding the identity of the actual signer in the ring. Through the requirement for user credit, the reliability of the review data is improved. At the same time, the distribution of rewards increases users' motivation. At last, the security analysis indicates that the LRSMR satisfies correctness, unforgeability, unconditional anonymity, linkability and nonslanderability. The simulation results illustrate that the LRSMR is efficient in terms of communication overhead and computation cost.
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