Intelligent robust control design of a precise positioning system

This paper addresses an intelligent uncertainty function to improve the robust stability and performance of H _∞ controlled system in terms of reduced conservatism. The system is identified, output performance and control signal requirements are controlled by proper selection of performance and control weighting functions. Adaptive Neuro Fuzzy Inference System (ANFIS) learns the uncertainty bounds of model uncertainty that results from unmodeled dynamics and parameter variations, then the developed uncertainty weighting function will be included in the synthesis of the H _∞ controller. ν-gap measure is utilized to validate the intelligent identified uncertainty bounds and measure the stability of the designed H _∞ controlled system as well. Experimental results on a servo motion system reveal the advantages of combining intelligent uncertainty identification and robust control. Improved performance is achieved. The proposed approach also allows for iterative experiment design.     

A Process Pattern Model for Tackling and Improving Big Data Quality

Data seldom create value by themselves. They need to be linked and combined from multiple sources, which can often come with variable data quality. The task of improving data quality is a recurring challenge. In this paper, we use a case study of a large telecom company to develop a generic process pattern model for improving data quality. The process pattern model is defined as a proven series of activities, aimed at improving the data quality given a certain context, a particular objective, and a specific set of initial conditions. Four different patterns are derived to deal with the variations in data quality of datasets. Instead of having to find the way to improve the quality of big data for each situation, the process model provides data users with generic patterns, which can be used as a reference model to improve big data quality.     

Lithium-Ion Desolvation Induced by Nitrate Additives Reveals New Insights into High Performance Lithium Batteries

Electrolyte additives have been widely used to address critical issues in current metal (ion) battery technologies. While their functions as solid electrolyte interface forming agents are reasonably well-understood, their interactions in the liquid electrolyte environment remain rather elusive. This lack of knowledge represents a significant bottleneck that hinders the development of improved electrolyte systems. Here, the key role of additives in promoting cation (e.g., Li⁺) desolvation is unraveled. In particular, nitrate anions (NO₃⁻) are found to incorporate into the solvation shells, change the local environment of cations (e.g., Li⁺) as well as their coordination in the electrolytes. The combination of these effects leads to effective Li⁺ desolvation and enhanced battery performance. Remarkably, the inexpensive NaNO₃ can successfully substitute the widely used LiNO₃ offering superior long-term stability of Li⁺ (de-)intercalation at the graphite anode and suppressed polysulfide shuttle effect at the sulfur cathode, while enhancing the performance of lithium–sulfur full batteries (initial capacity of 1153 mAh g⁻¹ at 0.25C) with Coulombic efficiency of ≈100% over 300 cycles. This work provides important new insights into the unexplored effects of additives and paves the way to developing improved electrolytes for electrochemical energy storage applications.     

Characteristics of practical control for point-to-point (PTP) positioning systems: Effect of design parameters and actuator saturation on positioning performance

In this study, a nominal characteristic trajectory following (NCTF) controller for point-to-point (PTP) positioning systems is introduced and its performance is evaluated. The NCTF controller consists of a nominal characteristic trajectory (NCT) and a compensator. The objective of the NCTF controller is to make the object motion follow the NCT and end at its origin. Therefore, the NCT is used as an intended object motion and the compensator is used to make the motion of the controlled object follow the NCT. The NCTF controller is designed based on a simple open-loop experiment of the object and no information except the NCT is necessary for controller design. The effectiveness of the NCTF controller is evaluated and discussed through simulations and experiments using an experimental rotary positioning system. The effect of the design parameters on the robustness of the NCTF controller to inertia and friction variations is evaluated and the influence of saturation on the positioning performance is examined. Moreover, the effects of the saturation on the positioning performance and robustness are compared with those of conventional PID ones. It is proved that the NCTF controller is much more accurate and robust to inertia and friction variations than the PID controllers, even if the saturation occurs.     

Phase Inversion Strategy to Flexible Freestanding Electrode: Critical Coupling of Binders and Electrolytes for High Performance Li–S Battery

Development of flexible and freestanding electrode is attracting great attention in lithium–sulfur (Li–S) batteries, but the severe capacity fading caused by the lithium polysulfides (PSs) shuttle effect remains challenging. Herein, a completely new polymeric binder of polyethersulfone is introduced. Not only it enables massive production of flexible/current‐free electrode by a novel concept of “phase‐inversion” approach but also the resultant polymeric networks can effectively trap the soluble polysulfides within the electrode, owing to the higher hydrophilicity and stronger affinity properties than the routine polyvinylidene fluoride. Coupling with polysulfide‐based electrolyte, the Li–S cell shows a higher capacity of 1141 mAh g^?1, a lower polarization of 192 mV, and a more stable capacity retention with 100% Coulombic efficiency over 100 cycles at 0.25C. The advantages of favored binder and electrolyte are further demonstrated in lithium‐ion sulfur full battery with lithiated graphite anode, which demonstrates much improved performance than those previously reported. This work not only introduces a novel strategy for flexible freestanding electrodes but also enlightens the importance of coupling electrodes and electrolytes to higher performances for Li–S battery.     

Interfacial and Interphasial Chemistry of Electrolyte Components to Invoke High-Performance Antimony Anodes and Non-Flammable Lithium-Ion Batteries

Electrolytes play a pivotal role to determine the electrode performances in lithium-ion batteries (LIBs). However, understanding the function of electrolyte components at the molecular scale remains elusive (e.g., salts, solvents, and additives), particularly how they arrange themselves and affect properties of the bulk, liquid-solid interfaces, and electrolyte decomposition, rendering a bottleneck for improving the electrolytes. Herein, the function of electrolyte components is thoroughly studied, from Li⁺ solvation structure in the bulk electrolyte, Li⁺ (de-)solvation behaviors at the electrolyte-solid interfaces, until the formation of solid electrolyte interphase (i.e., SEI) layer on the electrodes. Furthermore, a detailed model by taking into account the effects of solvent, additive, lithium salt, and concentration on the electrochemical properties of the Li⁺-solvent-anion complex to elucidate the electrode performances are depicted. As the ultimate benefit of this study, a completely new non-flammable ether-based electrolyte and stabilizing the promising antimony (Sb) anodes can be designed. Remarkably, a high-performance Sb anode that is superior to previous reports is obtained. This study provides a graphical model to unravel interfacial and interphasial behaviors of electrolyte components in LIBs, which is also significant for developing other metal-ion batteries.