Parts with high-quality freeform surfaces have been widely used in industries,which require strict quality control during the manufacturing process.Among all the industrial inspection methods,contact measurement with ...Parts with high-quality freeform surfaces have been widely used in industries,which require strict quality control during the manufacturing process.Among all the industrial inspection methods,contact measurement with coordinate measuring machines or computer numerical control machine tool is a fundamental technique due to its high accuracy,robustness,and universality.In this paper,the existing research in the contact measurement field is systematically reviewed.First,different configurations of the measuring machines are introduced in detail,which may have influence on the corresponding sampling and inspection path generation criteria.Then,the entire inspection pipeline is divided into two stages,namely the pre-inspection and post-inspection stages.The typical methods of each sub-stage are systematically overviewed and classified,including sampling,accessibility analysis,inspection path generation,probe tip radius compensation,surface reconstruction,and uncertainty analysis.Apart from those classical research,the applications of the emerging deep learning technique in some specific tasks of measurement are introduced.Furthermore,some potential and promising trends are provided for future investigation.展开更多
In this paper,the problem of guaranteed cost control and anti-windup design is studied for a class of switched systems with actuator saturation.The switching strategy and anti-windup compensator are designed to ensure...In this paper,the problem of guaranteed cost control and anti-windup design is studied for a class of switched systems with actuator saturation.The switching strategy and anti-windup compensator are designed to ensure the asymptotic stability of the closed-loop system and to obtain the minimum upper bound of the cost function.Some sufficient conditions for the existence of an anti-windup compensator of guaranteed cost are given by using the multiple Lyapunov functions method.On this basis,the minimum upper bound of the cost function is determined by solving the optimisation problem under the constraint of linear matrix inequality(LMI).Finally,a numerical example is given to verify the effectiveness of the proposed method.展开更多
For nonlinear continuous-time switched systems,the problem ofhowto overcome the controller vulnerability is studied when the saturating actuator is considered.The sufficient condition of non-fragile stabilisation of t...For nonlinear continuous-time switched systems,the problem ofhowto overcome the controller vulnerability is studied when the saturating actuator is considered.The sufficient condition of non-fragile stabilisation of the system is derived by using the method of multiple Lyapunov functions.Then,a switching law and the non-fragile state feedback controllers are designed such that the closed-loop system can be asymptotically stabilised at the origin.Finally,when some scalar parameters of the closed-loop system are given,the design issue of the non-fragile state feedback controllers and the switching law,which aim at enlarging the estimation of domain of attraction for closed-loop system,is transformed into a convex optimisation issue with linear matrix inequalities(LMI)constraints,and a numerical example is given to verify the effectiveness of the proposed method.展开更多
Nitric oxide(NO),γ-aminobutyric acid(GABA),and mannose(MAS)could be important regulators of plant growth and adaptation to water stress.The application of sodium nitroprusside(SNP,a NO donor),GABA,and MAS improved pl...Nitric oxide(NO),γ-aminobutyric acid(GABA),and mannose(MAS)could be important regulators of plant growth and adaptation to water stress.The application of sodium nitroprusside(SNP,a NO donor),GABA,and MAS improved plant growth under watersufficient conditions and effectively mitigated water stress damage to white clover.The metabonomic analysis showed that both SNP and GABA application resulted in a significant increase in myo-inositol content;the accumulation of mannose was commonly regulated by SNP and MAS;GABA and MAS induced the accumulation of aspartic acid,quinic acid,trehalose,and glycerol under water deficit.In addition,citric acid was uniquely up-regulated by SNP associated with tricarboxylic acid(TCA)cycle under water stress.GABAspecially induced the accumulation of GABA,glycine,methionine,and aconitic acid related to GABA shunt,amino acids metabolism,and TCA cycle in response to water stress.MAS uniquely enhanced the accumulation of asparagine,galactose,and D-pinitol in association with amino acids and sugars metabolism under water stress.SNP-,GABA-,and MAS-induced changes of metabolic profiles and associated metabolic pathways could contribute to enhanced stress tolerance via involvement in the TCA cycle for energy supply,osmotic adjustment,antioxidant defense,and signal transduction for stress defense in white clover.展开更多
To improve the efficiency and consistency of machined microlens array using single-point diamond turning technology,a theoretical model of surface form error is proposed in this paper.Then,a compensation method for th...To improve the efficiency and consistency of machined microlens array using single-point diamond turning technology,a theoretical model of surface form error is proposed in this paper.Then,a compensation method for this model is studied.In the proposed tool equivalent tilt angle model,the microlens array is regarded as a freeform surface.The corresponding curvature radius of the surface at each cutting point along the cutting direction is calculated by establishing a slow slide servo cutting model.In the spatial form error model,the assumption is that surface form error has a linear relationship with z-axis maximum speed vz.An empirical linear equation is obtained and verified,with a maximum deviation of 0.4μm.Then,after machining,the surface form error is measured and processed using on-machine measurement.The theoretical and measured surface form errors are consistent.The surface form error is compensated in the machining program.The peak-to-valley value is reduced from 5.4 to 0.6μm after compensation.Findings show that the single-point diamond turning and compensation method for the microlens array presented in this paper can predict the surface form error and significantly improve machining accuracy and consistency.展开更多
基金partially supported by the Natural Science Foundation of Shanghai(Grant No.22ZR1435200)the National Natural Science Foundation of China(Grant No.52075337)the Open Research Fund of State Key Laboratory of Digital Manufacturing and Equipment Technology,HUST(Grant No.DMETKF2022010)。
文摘Parts with high-quality freeform surfaces have been widely used in industries,which require strict quality control during the manufacturing process.Among all the industrial inspection methods,contact measurement with coordinate measuring machines or computer numerical control machine tool is a fundamental technique due to its high accuracy,robustness,and universality.In this paper,the existing research in the contact measurement field is systematically reviewed.First,different configurations of the measuring machines are introduced in detail,which may have influence on the corresponding sampling and inspection path generation criteria.Then,the entire inspection pipeline is divided into two stages,namely the pre-inspection and post-inspection stages.The typical methods of each sub-stage are systematically overviewed and classified,including sampling,accessibility analysis,inspection path generation,probe tip radius compensation,surface reconstruction,and uncertainty analysis.Apart from those classical research,the applications of the emerging deep learning technique in some specific tasks of measurement are introduced.Furthermore,some potential and promising trends are provided for future investigation.
基金the Natural Science Foundation of Liaoning Province of China[grant numbers 2020-MS-283 and 20180551014]the Scientific Research Fund of Education Department of Liaoning Province of China[grant number L2019016].
文摘In this paper,the problem of guaranteed cost control and anti-windup design is studied for a class of switched systems with actuator saturation.The switching strategy and anti-windup compensator are designed to ensure the asymptotic stability of the closed-loop system and to obtain the minimum upper bound of the cost function.Some sufficient conditions for the existence of an anti-windup compensator of guaranteed cost are given by using the multiple Lyapunov functions method.On this basis,the minimum upper bound of the cost function is determined by solving the optimisation problem under the constraint of linear matrix inequality(LMI).Finally,a numerical example is given to verify the effectiveness of the proposed method.
基金the Natural Science Foundation of Liaoning Province of China[2020-MS-283]the Scientific Research Fund of Education Department of Liaoning Province of China[L2019016]the Natural Science Foundation of Liaoning Province of China[20180551014].
文摘For nonlinear continuous-time switched systems,the problem ofhowto overcome the controller vulnerability is studied when the saturating actuator is considered.The sufficient condition of non-fragile stabilisation of the system is derived by using the method of multiple Lyapunov functions.Then,a switching law and the non-fragile state feedback controllers are designed such that the closed-loop system can be asymptotically stabilised at the origin.Finally,when some scalar parameters of the closed-loop system are given,the design issue of the non-fragile state feedback controllers and the switching law,which aim at enlarging the estimation of domain of attraction for closed-loop system,is transformed into a convex optimisation issue with linear matrix inequalities(LMI)constraints,and a numerical example is given to verify the effectiveness of the proposed method.
基金supported by the earmarked fund for Modern Agro-industry Technology Research System(No.CARS-34)the International Cooperation Project of Sichuan(Grant No.2018HH0067)the National Natural Science Foundation of China(Grant No.31702182)
文摘Nitric oxide(NO),γ-aminobutyric acid(GABA),and mannose(MAS)could be important regulators of plant growth and adaptation to water stress.The application of sodium nitroprusside(SNP,a NO donor),GABA,and MAS improved plant growth under watersufficient conditions and effectively mitigated water stress damage to white clover.The metabonomic analysis showed that both SNP and GABA application resulted in a significant increase in myo-inositol content;the accumulation of mannose was commonly regulated by SNP and MAS;GABA and MAS induced the accumulation of aspartic acid,quinic acid,trehalose,and glycerol under water deficit.In addition,citric acid was uniquely up-regulated by SNP associated with tricarboxylic acid(TCA)cycle under water stress.GABAspecially induced the accumulation of GABA,glycine,methionine,and aconitic acid related to GABA shunt,amino acids metabolism,and TCA cycle in response to water stress.MAS uniquely enhanced the accumulation of asparagine,galactose,and D-pinitol in association with amino acids and sugars metabolism under water stress.SNP-,GABA-,and MAS-induced changes of metabolic profiles and associated metabolic pathways could contribute to enhanced stress tolerance via involvement in the TCA cycle for energy supply,osmotic adjustment,antioxidant defense,and signal transduction for stress defense in white clover.
基金the National Natural Science Foundation of China(Grant No.52075332)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA25040000,XDA25040200,and XDA25040202).
文摘To improve the efficiency and consistency of machined microlens array using single-point diamond turning technology,a theoretical model of surface form error is proposed in this paper.Then,a compensation method for this model is studied.In the proposed tool equivalent tilt angle model,the microlens array is regarded as a freeform surface.The corresponding curvature radius of the surface at each cutting point along the cutting direction is calculated by establishing a slow slide servo cutting model.In the spatial form error model,the assumption is that surface form error has a linear relationship with z-axis maximum speed vz.An empirical linear equation is obtained and verified,with a maximum deviation of 0.4μm.Then,after machining,the surface form error is measured and processed using on-machine measurement.The theoretical and measured surface form errors are consistent.The surface form error is compensated in the machining program.The peak-to-valley value is reduced from 5.4 to 0.6μm after compensation.Findings show that the single-point diamond turning and compensation method for the microlens array presented in this paper can predict the surface form error and significantly improve machining accuracy and consistency.
