An Integrated Control Framework for Torque Vectoring and Active Suspension System

Four-wheel independently driven electric vehicles(FWID-EV)endow a flexible and scalable control framework to improve vehicle performance.This paper integrates the torque vectoring and active suspension system(ASS)to enhance the vehicle’s longitudinal and vertical motion control performance.While the nonlinear characteristic of the tire model leads to a relatively heavier computational burden.To facilitate the controller design and ease the load,a half-vehicle dynamics system is built and simplified to the linear-time-varying(LTV)model.Then a model predictive controller is developed by formulating the objective function by comprehensively considering the safety,energy-saving and comfort requirements.The in-wheel motor efficiency and the power loss of tire slip are treated as optimization indices in this work to reduce energy consumption.Finally,the effectiveness of the proposed controller is verified through the rapid-control-prototype(RCP)test.The results demonstrate the enhancement of the energy-saving as well as comfort on the basis of vehicle stability.

Automatic Miscalibration Detection and Correction of LiDAR and Camera Using Motion Cues

This paper aims to develop an automatic miscalibration detection and correction framework to maintain accurate calibration of LiDAR and camera for autonomous vehicle after the sensor drift.First,a monitoring algorithm that can continuously detect the miscalibration in each frame is designed,leveraging the rotational motion each individual sensor observes.Then,as sensor drift occurs,the projection constraints between visual feature points and LiDAR 3-D points are used to compute the scaled camera motion,which is further utilized to align the drifted LiDAR scan with the camera image.Finally,the proposed method is sufficiently compared with two representative approaches in the online experiments with varying levels of random drift,then the method is further extended to the offline calibration experiment and is demonstrated by a comparison with two existing benchmark methods.

Energy-Optimal Braking Control Using a Double-Layer Scheme for Trajectory Planning and Tracking of Connected Electric Vehicles

Most researches focus on the regenerative braking system design in vehicle components control and braking torque distribution,few combine the connected vehicle technologies into braking velocity planning.If the braking intention is accessed by the vehicle-to-everything communication,the electric vehicles(EVs)could plan the braking velocity for recovering more vehicle kinetic energy.Therefore,this paper presents an energy-optimal braking strategy(EOBS)to improve the energy efficiency of EVs with the consideration of shared braking intention.First,a double-layer control scheme is formulated.In the upper-layer,an energy-optimal braking problem with accessed braking intention is formulated and solved by the distance-based dynamic programming algorithm,which could derive the energy-optimal braking trajectory.In the lower-layer,the nonlinear time-varying vehicle longitudinal dynamics is transformed to the linear time-varying system,then an efficient model predictive controller is designed and solved by quadratic programming algorithm to track the original energy-optimal braking trajectory while ensuring braking comfort and safety.Several simulations are conducted by jointing MATLAB and CarSim,the results demonstrated the proposed EOBS achieves prominent regeneration energy improvement than the regular constant deceleration braking strategy.Finally,the energy-optimal braking mechanism of EVs is investigated based on the analysis of braking deceleration,battery charging power,and motor efficiency,which could be a guide to real-time control.

Combined Estimation of Vehicle Dynamic State and Inertial Parameter for Electric Vehicles Based on Dual Central Difference Kalman Filter Method

Distributed drive electric vehicles(DDEVs)possess great advantages in the viewpoint of fuel consumption,environment protection and traffic mobility.Whereas the effects of inertial parameter variation in DDEV control system become much more pronounced due to the drastic reduction of vehicle weights and body size,and inertial parameter has seldom been tackled and systematically estimated.This paper presents a dual central difference Kalman filter(DCDKF)where two Kalman filters run in parallel to simultaneously estimate vehicle different dynamic states and inertial parameters,such as vehicle sideslip angle,vehicle mass,vehicle yaw moment of inertia,the distance from the front axle to centre of gravity.The proposed estimation method only integrates and utilizes real-time measurements of hub torque information and other in-vehicle sensors from standard DDEVs.The four-wheel nonlinear vehicle dynamics estimation model considering payload variations,Pacejka tire model,wheel and motor dynamics model is developed,the observability of the DCDKF observer is analysed and derived via Lie derivative and differential geometry theory.To address system nonlinearities in vehicle dynamics estimation,the DCDKF and dual extended Kalman filter(DEKF)are also investigated and compared.Simulation with various maneuvers are carried out to verify the effectiveness of the proposed method using Matlab/Simulink-CarsimR.The results show that the proposed DCDKF method can effectively estimate vehicle dynamic states and inertial parameters despite the existence of payload variations and variable driving conditions.This research provides a boot-strapping procedure which can performs optimal estimation to estimate simultaneously vehicle system state and inertial parameter with high accuracy and real-time ability.

A single-longitudinal-mode continuous-wave Ho-(3＋)：YVO4 laser at 2.05 μm pumped by a Tm-fibre laser

We present a single-longitudinal-mode continuous-wave Ho^3＋：YVO4 laser at 2.05 μm pumped by a Tm-doped fibre laser. Use of a cavity etalon enables spectral selectivity for single-mode operation. The highest power achieved in the single longitudinal mode at 2052.5 nm is 282 mW at a slope efficiency of 6.9%, corresponding to an optical conversion efficiency of 3.0%. These features demonstrate that this single-longitudinal-mode Ho：YVO4 laser is suitable for use as a seed laser in some Lidar systems（e.g., coherent Lidar or differential absorption Lidar）. To the best of our knowledge, this is the first report on such a single-longitudinal-mode Ho：YVO4 laser at 2.05 μm.

Comparison of combined laparoscopic ureterolithotomy and flexible ureteroscopy with percutaneous nephrolithotomy for removing large impacted upper ureteral stones with concurrent renal stones

Objectives:The present study compared the safety and efficacy of combined laparoscopic ureterolithotomy(LU)and flexible ureteroscopy with percutaneous nephrolithotomy(PCNL)for removing large impacted upper ureteral stones with concurrent renal stones.Methods:This study included 52 patients who underwent combined LU and retrograde flexible ureteroscopy for removing renal stones(group A)or PCNL(group B)for removing large upper impacted ureteral stones and concurrent renal stones at our department from January 2014 to December 2016.Patient demographics,stone characteristics,and procedure-related parameters including stone-free rate,operation time,hospital stay after surgery,mean decrease in hemoglobin levels,visual analog scale(VAS)score,auxiliary procedure rate,and complication rate were compared between groups A and B.Results:Results of this study showed that both procedures were effective for removing large impacted upper ureteral stones with concurrent renal stones.The stone-free rate after a single procedure was 95.7%in group A and 89.7%in group B(p?0.62).The operation time was longer in group A than in group B(112.2±23.3 min versus 96.2±16.4 min,p?0.006).However,no significant difference was observed between the two groups with respect to the length of hospital stay after the surgery(5 days versus 6 days,p?0.06).The decrease in hemoglobin levels was significantly higher in group B than in group A(0.64±0.36 g/dL versus1.44±0.65 g/dL,p<0.0001).The mean VAS scores obtained at 24 hours(2.91±1.08 versus 5.10±1.01,p<0.0001)and 48 hours after the surgery(1.09±0.73 versus 2.28±0.96,p<0.0001)were significantly higher for group B than for group A.Moreover,the auxiliary procedure rate was higher in group B than in group A(6.9%versus 0%).Conclusion:These results indicate that both combined LU and flexible ureteroscopy and PCNL are suitable for removing large impacted upper ureteral stones with concurrent renal stones and are associated with a high rate of patients being stone free afterwards.Despite the longer operation time,the combined laparoscopic and endourological procedure may be associated with less postoperative pain and fewer major complications.However,the choice of treatment depends on the preferences of surgeons and patients.

Management of major vascular injury in laparoscopic urology

Objective:During the past three decades,laparoscopy has played a significant role in the management of urological disorders.This study aims to standardize the management of major vascular injury,which is a life-threatening complication in the laparoscopic urological procedures.Methods:A total of 8210 patients with the urological disorder,who underwent laparoscopic surgery at Sir Run Run Shaw Hospital from January 2000 to December 2018,were included in this retrospective study.Patients’data of the laparoscopic major vascular injury were collected and analyzed,and the basic principles of the procedure were summarized.Results:A total of 15(0.18%)cases of major vascular injury were found among the 8210 patients,and 2 of them were converted to open surgery.Although the type of laparoscopic surgery,causes,and management of major vascular injury among the patients were diverse,the main management strategies of major vascular injury in laparoscopic surgery were to keep the vision clear,control bleeding rapidly by clamping and compression,make full preparation for possibly needed liquid resuscitation,and try best to repair under laparoscope.If necessary,converse to open surgery.Conclusion:Although the reported incidence of major vascular injury in laparoscopic urological surgery is extremely low,such injury can result in high morbidity and mortality.It is important to rapidly identify the cause and strictly follow the standardized management for better outcomes.

Aldehyde oxidase mediated enantioselective metabolic health risk of dinotefuran

Chiral pollutants often pose significant differential environmental health risks.In this study,the biotransformation of chiral dinotefuran(DIN)and its enantioselective metabolic toxicity mechanisms have been systemically investigated.Firstly,reversedphase chromatography-high resolution mass spectrometry was developed to quantify the content of DIN R/S chiral enantiomer with pg level sensitivity,revealing a lower elimination rate constant(K_(e))of S-DIN(0.730 h^(-1))than R-DIN(0.746 h^(-1)).Secondly,the interaction mechanism between DIN metabolism and important endogenous bioactive molecules,such as aldehyde oxidase(AOX)and neurotransmitters,was revealed.The DIN nitro-group was converted into a guanidine group by the reducing site of nearby flavin adenine dinucleotide(FAD)in AOX with the preferred higher affinity of S-configuration.Meanwhile,the endogenous tryptophan(Trp)aldehyde metabolic intermediate,5-hydroxyindoleacetaldehyde(5-HIAL),provides a persistent electron donor for DIN reduction via the oxidation-catalyzed site in AOX,resulting in remarkable up-regulation of monoamine neurotransmitters such as serotonin and dopamine.Thirdly,the higher level of neurotransmitters further mediated dysregulation of oxylipin homeostasis via the serotonergic pathway,where S-DIN exhibited more pronounced liver lipid damage and environmental health risk with the accumulated lipid biomarkers,oxidized triglyceride(OxTG)and oxidized sphingomyelin(OxSM).This study elucidates the AOX-mediated enantioselectivity metabolic pathway of DIN,providing a new analytical method for chiral pollutants and paves the way for their health risk assessments.

An experimental demonstration of long-haul public-channel key distribution using matched superlattice physical unclonable function pairs

In a perfect security case of symmetric encryption,the secure key is generated from a true random number generator and cannot be reused.Moreover,it has the same code length as the total message.Furthermore,we require the secure key to be distributed by employing unconditionally secure methods.Apart from quantum secure direct communication(QSDC)that directly achieves the confidential transmission of secure information over a quantum channel without key distribution procedure[1–3],secure key generation and secure key distribution(SKD)are the two most remarkable challenges restricting the efficiency and security of a cryptosystem[4]in conventional secure communication systems.

Robust Cooperative Control of Multiple Autonomous Vehicles for Platoon Formation Considering Parameter Uncertainties

This paper proposes a robust cooperative control strategy for multiple autonomous vehicles to achieve safe and efficient platoon formation,and it analyzes the effects of vehicle stability boundaries and parameter uncertainties.The cooperative vehicle control framework is composed of the upper planning level and lower tracking control level.In the planning level,the trajectory of each vehicle is generated by using the multi-objective flocking algorithm to form the platoon.The parameters of the flocking algorithm are optimized to prevent the vehicle speed and yaw rate from going beyond their limits.In the lower level,to realize the stable platoon formation,a lumped disturbance observer is designed to gain the stable-state reference,and a distributed robust model predictive controller is proposed to achieve the offset-free trajectory tracking while downsizing the effects of parameter uncertainties.The simulation results show the proposed cooperative control strategy can achieve safe and efficient platoon formation.

Metabolic profile of chiral cobalt oxide nanoparticles in vitro and in vivo

In this study,we investigated the in vivo behaviors of chiral cobalt oxide nanoparticles(Co_(3)O_(4) NPs)stabilized with D-or L-cysteine(denoted D-or L-NPs,respectively),as representative chiral metal oxide NPs.Chiral Co_(3)O_(4) NPs exerted no observable cytotoxicity within the tested dose range.Both D-NPs and L-NPs were internalized by dendritic cells through caveola-dependent endocytosis,and L-NPs entered the cells faster than D-NPs.Significantly,a metabolic analysis indicated that chiral L-NPs had the same effect on the level of bile acids in the liver as D-NPs,which is attributed to the almost equal amount of farnesoid X receptor(FXR)induced by the chiral NPs.This study suggests that low chiroptical activity nanomaterials would not affect the metabolism and kinetics under physiological conditions even if there is some difference in their transport.

纸质图书和数字图书增值税税率差异比较

本文通过比较全球35个国家的图书增值税税率,发现图书增值税平均税率远低于增值税标准税率,纸质图书增值税平均税率低于数字图书增值税平均税率。随着信息技术的快速发展,数字图书已成为图书出版的重要组成部分,近年来一些国家相继降低数字图书增值税税率。为了促进知识经济发展,本文建议我国也应进一步降低图书增值税税率,统一纸质图书和数字图书增值税税率,并明确新兴出版物税目。

Stable trajectory planning and energyefficience control allocation of lane change maneuver for autonomous electric vehicle

Purpose–The purpose of this paper is to investigate problems in performing stable lane changes and tofind a solution to reduce energy consumption of autonomous electric vehicles.Design/methodology/approach–An optimization algorithm,model predictive control(MPC)and Karush–Kuhn–Tucker(KKT)conditions are adopted to resolve the problems of obtaining optimal lane time,tracking dynamic reference and energy-efficient allocation.In this paper,the dynamic constraints of vehicles during lane change arefirst established based on the longitudinal and lateral force coupling characteristics and the nominal reference trajectory.Then,by optimizing the lane change time,the yaw rate and lateral acceleration that connect with the lane change time are limed.Furthermore,to assure the dynamic properties of autonomous vehicles,the real system inputs under the restraints are obtained by using the MPC method.Based on the gained inputs and the efficient map of brushless direct-current in-wheel motors(BLDC IWMs),the nonlinear cost function which combines vehicle dynamic and energy consumption is given and the KKT-based method is adopted.Findings–The effectiveness of the proposed control system is verified by numerical simulations.Consequently,the proposed control system can successfully achieve stable trajectory planning,which means that the yaw rate and longitudinal and lateral acceleration of vehicle are within stability boundaries,which accomplishes accurate tracking control and decreases obvious energy consumption.Originality/value–This paper proposes a solution to simultaneously satisfy stable lane change maneuvering and reduction of energy consumption for autonomous electric vehicles.Different from previous path planning researches in which only the geometric constraints are involved,this paper considers vehicle dynamics,and stability boundaries are established in path planning to ensure the feasibility of the generated reference path.

Biomimetic nanoporous aerogels from branched aramid nanofibers combining high heat insulation and compressive strength

Materials combining efficient thermal insulation and high mechanical properties are needed in many areas of technology.Various aerogels provide a convenient design framework for thermal insulators,but they are often brittle.Furthermore,the spectrum of advanced properties is constantly expanding while requirements to the degree of control of the three‐dimensional gel‐forming network is con-stantly increasing.Here,we report on biomimetic aramid nanofibers aerogels with the structure replicating articular cartilage,prepared by supercritical drying of 3D networks held together by hydrogen bonds.Owing to the branching morphology of the nanofibers,the three‐dimensional nanoscale networks with extensive percolation and high interconnectivity can be obtained.The aerogels showed high porosity with an average open pore size of 21.5 nm and corre-spondingly low specific density of 0.0081 g/cm3.The aerogels also possess a high compressive strength of 825 kPa at a strain of 80%.Due to the unique aramid chemistry of the parent nanofibers,aramid aerogels combine low thermal con-ductivity of 0.026 W/m·K with high thermal stability up to 530°C,which is unusually high for polymeric and composite materials of any type,opening a broad range of applications from electronics to space travel.

A BIE-BASED DtN-FEM FOR FLUID-SOLID INTERACTION PROBLEMS

In this paper, we are concerned with the coupling of finite element methods and bound- ary integral equation methods solving the classical fluid-solid interaction problem in two dimensions. The original transmission problem is reduced to an equivalent nonlocal bound- ary value problem via introducing a Dirichlet-to-Neumann mapping by the direct boundary integral equation method. We show the existence and uniqueness of the solution for the corresponding variational equation. Numerical results based on the finite element method coupled with the standard Galerkin boundary element method, the fast multipole method and the NystrSm method for approximating the DtN mapping are provided to illustrate the efficiency and accuracy of the numerical schemes.