This paper proposes a separated trajectory tracking controller for fishing ships at sea state level 6 to solve the trajectory tracking problem of a fishing ship in a 6-level sea state,and to adapt to different working...This paper proposes a separated trajectory tracking controller for fishing ships at sea state level 6 to solve the trajectory tracking problem of a fishing ship in a 6-level sea state,and to adapt to different working environments and safety requirements.The nonlinear feedback method is used to improve the closed-loop gain shaping algorithm.By introducing the sine function,the problem of excessive control energy of the system can be effectively solved.Moreover,an integral separation design is used to solve the influence of the integral term in conventional PID controllers on the transient performance of the system.In this paper,a common 32.98 m large fiberglass reinforced plastic(FRP)trawler is adopted for simulation research at the winds scale of Beaufort No.7.The results show that the track error is smaller than 3.5 m.The method is safe,feasible,concise and effective and has popularization value in the direction of fishing ship trajectory tracking control.This method can be used to improve the level of informatization and intelligence of fishing ships.展开更多
By manipulating the phase map of a wavefront of light using a spatial light modulator,the scattered light can be sharply focused on a specific target.Several iterative optimization algo-rithrns for obtaining the optim...By manipulating the phase map of a wavefront of light using a spatial light modulator,the scattered light can be sharply focused on a specific target.Several iterative optimization algo-rithrns for obtaining the optimumn phase map have been explored.However,there has not been a comparative study on the performance of these algorithms.In this paper,six optimization algorithms for wavefront shaping inchuding continuous sequential,partitioning algorithm,transmission matrix estimation method,particle swarm optimization,genetic algorithm(GA),and simulated annealing(SA)are discussed and compared based on their efficiency when introduced with various measurement noise levels.展开更多
Rotor clearance is necessary for the safe operation of twin-screw compressors,and it has a major impact on the performance of twin-screw compressors.The purpose of this study was to obtain a rotor tooth profile with r...Rotor clearance is necessary for the safe operation of twin-screw compressors,and it has a major impact on the performance of twin-screw compressors.The purpose of this study was to obtain a rotor tooth profile with reasonable meshing clearance on the rotor end surface,so that the clearance on the rotor contact line would be uniform and the rotor could be smoothly meshed.Under ideal conditions,the rotor of a screw compressor should have no clearance or interference.However,owing to assembly errors,thermal compression,stress deformation,and other factors,a rotor without backlash modification will inevitably produce interference during operation.A new design method based on the Alpha shape solution was proposed to achieve an efficient and high-precision design of the clearance of the twin-screw rotor profile.This method avoids the complex analytical calculations in the traditional envelope principle.The best approximation of the points on the rotor conjugate motion sweeping surface in the points is illuminated using a specific color.The sweeping surface of the screw rotor single-tooth profile is roughly scanned to capture the base point set of the sweeping surface boundary points.The chord length and tilt angle of each interval are calculated using the value of the base point set to adjust the position,phase,and magnification of each interval sweeping surface.Finally,the data point set is converted to the same coordinate system to generate the conjugated rotor profile.An example was used to verify the feasibility and adaptability of this method.Based on the equidistant profile method,the clearance between male and female rotors of a screw compressor was obtained under actual operation conditions.Therefore,this study provides a basis for the meshing clearance design in the machining of twin-screw compressor rotors.展开更多
A new adaptive beam intensity shaping technique based on the combination of a 19-element piezo-electricity deformable mirror （DM） and a global genetic algorithm is presented. This technique can adaptively adjust the...A new adaptive beam intensity shaping technique based on the combination of a 19-element piezo-electricity deformable mirror （DM） and a global genetic algorithm is presented. This technique can adaptively adjust the voltages of the 19 actuators on the DM to reduce the difference between the target beam shape and the actual beam shape. Numerical simulations and experimental results show that within the stroke range of the DM, this technique can be well used to create the given beam intensity profiles on the focal plane.展开更多
Methods for identifying sub-regional material parameters of concrete damsusing incomplete rnodal data are presented. With the measurements of the first frequency andincomplete mode shape, identification methods were b...Methods for identifying sub-regional material parameters of concrete damsusing incomplete rnodal data are presented. With the measurements of the first frequency andincomplete mode shape, identification methods were built by both the output error approach and theminimum deviation approach. The minimum deviation approach was introduced as physical constraints tothe output error approach, allowing the output error-minimum deviation coupled approach to bedeveloped. The simulated annealing-simplex shape algorithm was applied to solve the identificationmodels. Numerical simulations were carried out with noisy incomplete measurements to illustrate therobustness of the methods.展开更多
基金supported by Liaoning Provincial Department of Education 2023 Basic Research Projects for Universities and Colleges(Grant No.JYTQN2023131)Liaoning Provincial Science and Technology Program:Cooperative Control and Recognition of Unmanned Vessels for Fishing Vessel Operation Scenarios(Grant No.600024003)Liaoning Provincial Department of Education Scientific Research Funding Project(Grant No.LJKZ0726).
文摘This paper proposes a separated trajectory tracking controller for fishing ships at sea state level 6 to solve the trajectory tracking problem of a fishing ship in a 6-level sea state,and to adapt to different working environments and safety requirements.The nonlinear feedback method is used to improve the closed-loop gain shaping algorithm.By introducing the sine function,the problem of excessive control energy of the system can be effectively solved.Moreover,an integral separation design is used to solve the influence of the integral term in conventional PID controllers on the transient performance of the system.In this paper,a common 32.98 m large fiberglass reinforced plastic(FRP)trawler is adopted for simulation research at the winds scale of Beaufort No.7.The results show that the track error is smaller than 3.5 m.The method is safe,feasible,concise and effective and has popularization value in the direction of fishing ship trajectory tracking control.This method can be used to improve the level of informatization and intelligence of fishing ships.
文摘By manipulating the phase map of a wavefront of light using a spatial light modulator,the scattered light can be sharply focused on a specific target.Several iterative optimization algo-rithrns for obtaining the optimumn phase map have been explored.However,there has not been a comparative study on the performance of these algorithms.In this paper,six optimization algorithms for wavefront shaping inchuding continuous sequential,partitioning algorithm,transmission matrix estimation method,particle swarm optimization,genetic algorithm(GA),and simulated annealing(SA)are discussed and compared based on their efficiency when introduced with various measurement noise levels.
文摘Rotor clearance is necessary for the safe operation of twin-screw compressors,and it has a major impact on the performance of twin-screw compressors.The purpose of this study was to obtain a rotor tooth profile with reasonable meshing clearance on the rotor end surface,so that the clearance on the rotor contact line would be uniform and the rotor could be smoothly meshed.Under ideal conditions,the rotor of a screw compressor should have no clearance or interference.However,owing to assembly errors,thermal compression,stress deformation,and other factors,a rotor without backlash modification will inevitably produce interference during operation.A new design method based on the Alpha shape solution was proposed to achieve an efficient and high-precision design of the clearance of the twin-screw rotor profile.This method avoids the complex analytical calculations in the traditional envelope principle.The best approximation of the points on the rotor conjugate motion sweeping surface in the points is illuminated using a specific color.The sweeping surface of the screw rotor single-tooth profile is roughly scanned to capture the base point set of the sweeping surface boundary points.The chord length and tilt angle of each interval are calculated using the value of the base point set to adjust the position,phase,and magnification of each interval sweeping surface.Finally,the data point set is converted to the same coordinate system to generate the conjugated rotor profile.An example was used to verify the feasibility and adaptability of this method.Based on the equidistant profile method,the clearance between male and female rotors of a screw compressor was obtained under actual operation conditions.Therefore,this study provides a basis for the meshing clearance design in the machining of twin-screw compressor rotors.
基金the National"863"Project under Grant No.Aosk003.
文摘A new adaptive beam intensity shaping technique based on the combination of a 19-element piezo-electricity deformable mirror （DM） and a global genetic algorithm is presented. This technique can adaptively adjust the voltages of the 19 actuators on the DM to reduce the difference between the target beam shape and the actual beam shape. Numerical simulations and experimental results show that within the stroke range of the DM, this technique can be well used to create the given beam intensity profiles on the focal plane.
文摘Methods for identifying sub-regional material parameters of concrete damsusing incomplete rnodal data are presented. With the measurements of the first frequency andincomplete mode shape, identification methods were built by both the output error approach and theminimum deviation approach. The minimum deviation approach was introduced as physical constraints tothe output error approach, allowing the output error-minimum deviation coupled approach to bedeveloped. The simulated annealing-simplex shape algorithm was applied to solve the identificationmodels. Numerical simulations were carried out with noisy incomplete measurements to illustrate therobustness of the methods.
