Author Center
Editor Work
Peer Review
Editorial Entry
Email Alert
RSS2018 Vol. 37, No. 5
Display Method:
2018, 37(5): 657-662.
doi: 10.13433/j.cnki.1003-8728.2018.0501
PDF 914KB
Abstract:
A method of distinguishing motifs of moving chain elements is proposed to analyze the constitutive elements of kinematic chains with multiple joints, and study isomorphism identification of mechanical synthesis and optimization which can effectively describe information of multiple joints and components in the kinematic chain. In fact, there is the same train of thought for simple joints and multiple joints on value added matrix. Compared with traditional vertex adjacency matrix and transformation adjacency matrix, the value-added matrix has the characteristics of more information, convenience and easily-construction. The isomorphism of the kinematic chain is identified with computer to calculate the eigenvalue and eigenvector of the value-added matrix, in which the method has the characteristics of accuracy and simplicity. A quick and efficient way is provided by value-added matrix to describe various types of kinematic chains.
A method of distinguishing motifs of moving chain elements is proposed to analyze the constitutive elements of kinematic chains with multiple joints, and study isomorphism identification of mechanical synthesis and optimization which can effectively describe information of multiple joints and components in the kinematic chain. In fact, there is the same train of thought for simple joints and multiple joints on value added matrix. Compared with traditional vertex adjacency matrix and transformation adjacency matrix, the value-added matrix has the characteristics of more information, convenience and easily-construction. The isomorphism of the kinematic chain is identified with computer to calculate the eigenvalue and eigenvector of the value-added matrix, in which the method has the characteristics of accuracy and simplicity. A quick and efficient way is provided by value-added matrix to describe various types of kinematic chains.
2018, 37(5): 663-668.
doi: 10.13433/j.cnki.1003-8728.2018.0502
Abstract:
To improve the efficiency of turbine blades and output power of turbine generators, a method for modifying blade and optimizing design was put forward. Firstly, the blade modification was in progress by remodeling the guide roller type lines and turbine airfoil profiles respectively, and matching guide rollers and turbine groups with different blade profiles. Then, the flow field analysis was conducted to investigate the effects of the different structures of guide rollers on the turbine performance. In this way, the high efficiency and large torque impeller combinations would be selected. Moreover, the combination of BP neural network and Fmincon function and genetic algorithm method was adopted to conduct optimized analysis. Specifically, the optimized results indicated that the efficiency of single stage turbine increased by 4.74%. The maximum work efficiency increased from 64.824% to 79.4%, which improved about 14.6%. The ideal output power had improved by 274.7 W.
To improve the efficiency of turbine blades and output power of turbine generators, a method for modifying blade and optimizing design was put forward. Firstly, the blade modification was in progress by remodeling the guide roller type lines and turbine airfoil profiles respectively, and matching guide rollers and turbine groups with different blade profiles. Then, the flow field analysis was conducted to investigate the effects of the different structures of guide rollers on the turbine performance. In this way, the high efficiency and large torque impeller combinations would be selected. Moreover, the combination of BP neural network and Fmincon function and genetic algorithm method was adopted to conduct optimized analysis. Specifically, the optimized results indicated that the efficiency of single stage turbine increased by 4.74%. The maximum work efficiency increased from 64.824% to 79.4%, which improved about 14.6%. The ideal output power had improved by 274.7 W.
2018, 37(5): 669-674.
doi: 10.13433/j.cnki.1003-8728.2018.0503
Abstract:
A new closed loop adaptive control system of GA-RBF neural network is designed to solve the problem of incomplete information and external disturbance of multilink robot arm model system. The system uses radial basis function (RBF) neural network to approximate and compensate the system model errors and external disturbance. Based on the computed torque method of manipulator, it realizes trajectory tracking control; based on genetic algorithm (GA) and the online optimization of RBF network weights, it ensures that the manipulator control system can get stable in a shorter period of time, to achieve high precision tracking trajectory, and improves the performance of trajectory tracking. The effectiveness of the proposed method is verified by the results of MATLAB simulation.
A new closed loop adaptive control system of GA-RBF neural network is designed to solve the problem of incomplete information and external disturbance of multilink robot arm model system. The system uses radial basis function (RBF) neural network to approximate and compensate the system model errors and external disturbance. Based on the computed torque method of manipulator, it realizes trajectory tracking control; based on genetic algorithm (GA) and the online optimization of RBF network weights, it ensures that the manipulator control system can get stable in a shorter period of time, to achieve high precision tracking trajectory, and improves the performance of trajectory tracking. The effectiveness of the proposed method is verified by the results of MATLAB simulation.
2018, 37(5): 675-682.
doi: 10.13433/j.cnki.1003-8728.2018.0504
Abstract:
A truss structure topology optimization feature-line(axis of the turss) extraction method is proposed for the problem of the two-dimensional truss structure topology optimization manufacturing. The continuum structure is optimized based on the evolutionary structural optimization method (ESO). The center point coordinates of the topological area are extracted according to the truss topology optimization result. The topological area is divided based on the truss linear characteristics and then the topological area feature-line mathematical model is established. The truss nodes are determined and combined with the feature-line mathematical model and then the radius of the nodes merging area is introduced to establish the truss nodes position quadratic optimization mathematical model. Finally, the truss topology optimization result(feature-line) oriented to manufacturing is extracted based on the optimal truss node position. Three classical examples are used to verify the effectiveness of the feature-line extraction method.
A truss structure topology optimization feature-line(axis of the turss) extraction method is proposed for the problem of the two-dimensional truss structure topology optimization manufacturing. The continuum structure is optimized based on the evolutionary structural optimization method (ESO). The center point coordinates of the topological area are extracted according to the truss topology optimization result. The topological area is divided based on the truss linear characteristics and then the topological area feature-line mathematical model is established. The truss nodes are determined and combined with the feature-line mathematical model and then the radius of the nodes merging area is introduced to establish the truss nodes position quadratic optimization mathematical model. Finally, the truss topology optimization result(feature-line) oriented to manufacturing is extracted based on the optimal truss node position. Three classical examples are used to verify the effectiveness of the feature-line extraction method.
2018, 37(5): 683-689.
doi: 10.13433/j.cnki.1003-8728.2018.0505
Abstract:
In order to replace labor with machines to handle the water logging problems caused by the blockage, and improve the intelligence of machines under the unstructured environment, in this paper we design a dredge wheeled robot with adaptive diameter, and propose a plumbing robot oriented model based on the theory of Coexisting-cooperative-cognitive robot. By building three sensory systems of vision, proximity and tactile, the end actuator of the robot performs the adaptive path planning at the optimal moving speed and improves the efficiency of the pipeline dredging. The simulation results show that the multimodal perception model of pipeline dredge robot has certain feasibility and practicability.
In order to replace labor with machines to handle the water logging problems caused by the blockage, and improve the intelligence of machines under the unstructured environment, in this paper we design a dredge wheeled robot with adaptive diameter, and propose a plumbing robot oriented model based on the theory of Coexisting-cooperative-cognitive robot. By building three sensory systems of vision, proximity and tactile, the end actuator of the robot performs the adaptive path planning at the optimal moving speed and improves the efficiency of the pipeline dredging. The simulation results show that the multimodal perception model of pipeline dredge robot has certain feasibility and practicability.
2018, 37(5): 690-697.
doi: 10.13433/j.cnki.1003-8728.2018.0506
Abstract:
In order to solve the problem that multiple performance indicators of adaptive cruise control (ACC) system are uncoordinated and imperfect, a ACC algorithm based on model predictive control and optimal control is proposed by considering the performance indicators and the driving and braking abilities of vehicle. According to longitudinal kinematic characteristics between the host vehicle and the vehicle in front, the discrete system state space expression is established and a saturated function is introduced. The weighted sum of squares of the output variables is defined as the objective function for the coordinate multiple performance indicators. Finally, the problem of solving the objective function is transformed into a one-dimensional extremum problem. The simulation results verify the effectiveness of the proposed algorithms in safe inter-vehicle distance maintenance and the feasibility of coordinating multi-performance indicators.
In order to solve the problem that multiple performance indicators of adaptive cruise control (ACC) system are uncoordinated and imperfect, a ACC algorithm based on model predictive control and optimal control is proposed by considering the performance indicators and the driving and braking abilities of vehicle. According to longitudinal kinematic characteristics between the host vehicle and the vehicle in front, the discrete system state space expression is established and a saturated function is introduced. The weighted sum of squares of the output variables is defined as the objective function for the coordinate multiple performance indicators. Finally, the problem of solving the objective function is transformed into a one-dimensional extremum problem. The simulation results verify the effectiveness of the proposed algorithms in safe inter-vehicle distance maintenance and the feasibility of coordinating multi-performance indicators.
2018, 37(5): 698-703.
doi: 10.13433/j.cnki.1003-8728.2018.0507
Abstract:
In order to enhance the loading performance and efficiency of a thin coal seam shearer, the discrete element simulation model of its cutting unit was constructed based on the PRO/E, EDEM, MATLAB. The complicated coal rock cutting process of the shearer was simulated; the corresponding loading rate was obtained. The law of influence of traction speed, roller speed and cutting depth on the shearer's loading rate was studied based on the single factor analysis method. The various factors of influence on the shearer's loading rate were studied with the multi-factor analysis method, and the optimal design parameters of the loading performance were obtained. The study results show that, based on the actual working conditions, the optimal design scheme of the new thin coal seam shearer for enhancing its coal loading performance is:the cutting depth of the drum is 700 mm; the traction speed is 9 m/min; the roller speed is 58 r/min; the loading rate is 26% higher than before optimization. The results provide a new method for the research and optimization of coal loading performance of the shearer's drum.
In order to enhance the loading performance and efficiency of a thin coal seam shearer, the discrete element simulation model of its cutting unit was constructed based on the PRO/E, EDEM, MATLAB. The complicated coal rock cutting process of the shearer was simulated; the corresponding loading rate was obtained. The law of influence of traction speed, roller speed and cutting depth on the shearer's loading rate was studied based on the single factor analysis method. The various factors of influence on the shearer's loading rate were studied with the multi-factor analysis method, and the optimal design parameters of the loading performance were obtained. The study results show that, based on the actual working conditions, the optimal design scheme of the new thin coal seam shearer for enhancing its coal loading performance is:the cutting depth of the drum is 700 mm; the traction speed is 9 m/min; the roller speed is 58 r/min; the loading rate is 26% higher than before optimization. The results provide a new method for the research and optimization of coal loading performance of the shearer's drum.
2018, 37(5): 704-708.
doi: 10.13433/j.cnki.1003-8728.2018.0508
Abstract:
A series of molecular dynamics simulations has been performed to study the surface deformation behavior and piles generation process of Fe3Al scratched by an atomic force microscopy probe. A scratching test is carried out to examine the generation of piles and its effects on surface appearance of a groove. Simulation results show that the generation of piles is a two-stage process. At the growing stage, the height of piles increases continuously. At the stable stage, the height of piles rarely changes. Some atoms gradually depart into two pieces with the movement of tip, which adhere to tip at the back. Additional scratching tests are carried out to examine the effects of scratch depth and scratch velocity on the generation of piles. The test results show that the height of piles increase with the increase of scratch depth, while the scratch velocity do not change the deformation behavior of substrate. The greater scratch velocity, however, can advance the entering of the stable stage.
A series of molecular dynamics simulations has been performed to study the surface deformation behavior and piles generation process of Fe3Al scratched by an atomic force microscopy probe. A scratching test is carried out to examine the generation of piles and its effects on surface appearance of a groove. Simulation results show that the generation of piles is a two-stage process. At the growing stage, the height of piles increases continuously. At the stable stage, the height of piles rarely changes. Some atoms gradually depart into two pieces with the movement of tip, which adhere to tip at the back. Additional scratching tests are carried out to examine the effects of scratch depth and scratch velocity on the generation of piles. The test results show that the height of piles increase with the increase of scratch depth, while the scratch velocity do not change the deformation behavior of substrate. The greater scratch velocity, however, can advance the entering of the stable stage.
2018, 37(5): 709-714.
doi: 10.13433/j.cnki.1003-8728.2018.0509
Abstract:
This paper proposes a structural design about 3-PRC compliant parallel micromanipulator integrated with a novel secondary lever amplification mechanism driven by piezoelectric actuator, which can realize translate motion along X/Y/Z axis, and the theoretical amplification ratio and the finite element simulation analysis magnification ratio of the secondary lever amplification mechanism are 8.772 and 8.245, respectively. The kinematics mathematical models are established with vector method, and the forward solution, inverse solution and Jacobian matrix are also derived at first. Then, the workspace of the stage is obtained by MATLAB and decoupling characteristics are analyzed and validated by finite element method. The result showed that the coupling error of the mechanism is small, and this 3-PRC micromanipulator can achieve micro/nano level motion with three degrees of freedom (mechanics).
This paper proposes a structural design about 3-PRC compliant parallel micromanipulator integrated with a novel secondary lever amplification mechanism driven by piezoelectric actuator, which can realize translate motion along X/Y/Z axis, and the theoretical amplification ratio and the finite element simulation analysis magnification ratio of the secondary lever amplification mechanism are 8.772 and 8.245, respectively. The kinematics mathematical models are established with vector method, and the forward solution, inverse solution and Jacobian matrix are also derived at first. Then, the workspace of the stage is obtained by MATLAB and decoupling characteristics are analyzed and validated by finite element method. The result showed that the coupling error of the mechanism is small, and this 3-PRC micromanipulator can achieve micro/nano level motion with three degrees of freedom (mechanics).
2018, 37(5): 715-720.
doi: 10.13433/j.cnki.1003-8728.2018.0510
Abstract:
In view of the influence of joint geometric error on the motion and accuracy of a heavy-load manipulator, using PID neurons with multiple input and multiple output optimization characteristics, a multi-objective heavy-load manipulator error optimization method based on PID neurons is put forward. The key factor of precision manipulator's error is studied and the relationship between load mapping and manipulator's multi-precision output target is analyzed. Then, the relationship between PID controller and neural network and the transfer relationship for the heavy-load manipulator's movement precision are explored. The mathematical model between simultaneously derived manipulator pose, velocity and acceleration and joint geometry error is established. Finally, the trend of influence of the manipulator's joint error on the movement accuracy is studied and simulated with the SCARA software. The simulation results show that the influence of joint geometric errors on the heavy manipulator can be effectively reduced with the multi-objective optimization method based on the PID neural network, and the rationality of the method is verified.
In view of the influence of joint geometric error on the motion and accuracy of a heavy-load manipulator, using PID neurons with multiple input and multiple output optimization characteristics, a multi-objective heavy-load manipulator error optimization method based on PID neurons is put forward. The key factor of precision manipulator's error is studied and the relationship between load mapping and manipulator's multi-precision output target is analyzed. Then, the relationship between PID controller and neural network and the transfer relationship for the heavy-load manipulator's movement precision are explored. The mathematical model between simultaneously derived manipulator pose, velocity and acceleration and joint geometry error is established. Finally, the trend of influence of the manipulator's joint error on the movement accuracy is studied and simulated with the SCARA software. The simulation results show that the influence of joint geometric errors on the heavy manipulator can be effectively reduced with the multi-objective optimization method based on the PID neural network, and the rationality of the method is verified.
2018, 37(5): 721-728.
doi: 10.13433/j.cnki.1003-8728.2018.0511
Abstract:
To solve the difficulties of discrete surface processing, the cutting path plan for discrete surface was discussed. The generating algorithms of cutting contact points and cutting location points were proposed. The two kinds of velocity interpolation algorithms for cutting location points were compared. A cutting contact points generation method based on the Zernike polynomials using local points data fitting and a Z-direction cutting tools geometry compensation method were proposed. In order to verify the accuracy of the cutting path plan, the MATLAB software was used in simulation of toric spectacle lenses. The cutting path plan and processing experiments for both toric spectacle lenses and progressive-addition lenses proved that discrete surface can be successfully and accurately machined by the proposed method without whole surface points data fitting.
To solve the difficulties of discrete surface processing, the cutting path plan for discrete surface was discussed. The generating algorithms of cutting contact points and cutting location points were proposed. The two kinds of velocity interpolation algorithms for cutting location points were compared. A cutting contact points generation method based on the Zernike polynomials using local points data fitting and a Z-direction cutting tools geometry compensation method were proposed. In order to verify the accuracy of the cutting path plan, the MATLAB software was used in simulation of toric spectacle lenses. The cutting path plan and processing experiments for both toric spectacle lenses and progressive-addition lenses proved that discrete surface can be successfully and accurately machined by the proposed method without whole surface points data fitting.
2018, 37(5): 729-735.
doi: 10.13433/j.cnki.1003-8728.2018.0512
Abstract:
For large holes with significant curvature change in scattered point clouds, the reverse engineering software usually has failure. In order to build up a complete point cloud model with a higher accuracy of hole repairing, an improved radial basis function (RBF) networks algorithm was exploited, where the rival penalized competitive learning (RPCL) algorithm was combined with the fuzzy clustering means (FCM) to perfect the traditional RBF networks, and the hybrid RPCL-FCM-RBF algorithm was then examined by applying it to two different scattered point clouds from scanned objects:a bucket of an excavator and a car. The experimental results indicate that the suggested method shows better hole-filling performance than the software and that the proposed algorithm has a superior prediction capability compared with the conventional RBF algorithm. The favorable fidelity and efficiency make it a promising candidate for many practical applications.
For large holes with significant curvature change in scattered point clouds, the reverse engineering software usually has failure. In order to build up a complete point cloud model with a higher accuracy of hole repairing, an improved radial basis function (RBF) networks algorithm was exploited, where the rival penalized competitive learning (RPCL) algorithm was combined with the fuzzy clustering means (FCM) to perfect the traditional RBF networks, and the hybrid RPCL-FCM-RBF algorithm was then examined by applying it to two different scattered point clouds from scanned objects:a bucket of an excavator and a car. The experimental results indicate that the suggested method shows better hole-filling performance than the software and that the proposed algorithm has a superior prediction capability compared with the conventional RBF algorithm. The favorable fidelity and efficiency make it a promising candidate for many practical applications.
2018, 37(5): 736-741.
doi: 10.13433/j.cnki.1003-8728.2018.0513
Abstract:
The cantilever is widely used in fiber Bragg grating (FBG) sensors for its excellent mechanics response characteristics. However, the FBGs are packaged in the most existing cantilever surfaces ofcantilever sensors. These sensors cannot survive in the deep water without high-pressure resistance and sea-water corrosion resistance. The new FBG sensor with cantilever structure is developed to monitor the force under the deep water. In order to resist the corrosion and pressure, the FBG was packaged inside the cantilever that is made by anticorrosion material. It is shown that it works properly at a pressure of 30 MPa, pressure sensitivity of -3.79 pm/MPa, force sensitivity of 2.79 pm/N and temperature sensitivity of 30.93 pm/℃. The wavelength change is well linearly to the temperature and pressure change, and all linearly dependent coefficients are higher than 0.99. The further environmental compensation is feasible. According to the computer simulations, test results and sensitivity analysis, the error from the package craft and test conditions is obtained.
The cantilever is widely used in fiber Bragg grating (FBG) sensors for its excellent mechanics response characteristics. However, the FBGs are packaged in the most existing cantilever surfaces ofcantilever sensors. These sensors cannot survive in the deep water without high-pressure resistance and sea-water corrosion resistance. The new FBG sensor with cantilever structure is developed to monitor the force under the deep water. In order to resist the corrosion and pressure, the FBG was packaged inside the cantilever that is made by anticorrosion material. It is shown that it works properly at a pressure of 30 MPa, pressure sensitivity of -3.79 pm/MPa, force sensitivity of 2.79 pm/N and temperature sensitivity of 30.93 pm/℃. The wavelength change is well linearly to the temperature and pressure change, and all linearly dependent coefficients are higher than 0.99. The further environmental compensation is feasible. According to the computer simulations, test results and sensitivity analysis, the error from the package craft and test conditions is obtained.
2018, 37(5): 742-746.
doi: 10.13433/j.cnki.1003-8728.2018.0514
Abstract:
In order to solve the problem that the penetration fuse circuit subjected to a large overload shock will produce circuit vibration noise, the mathematic model between the penetrating impact vibration excitation and the circuit vibration noise response has been established in the paper. And a noise elimination method based on wavelet analysis has been proposed. The method in the paper uses the wavelet transform to analyze the impact exciting signal of the penetration fuse and uses the Gaussian function to fit the output vibration noise response signal of circuit. Then the correlation function between these two signals can be established. The output noise processing algorithm of circuit is designed for vibration excitation based on this. The simulation results show that the algorithm has obvious de-noising effect on the noise of the penetration fuse circuit caused by impact vibration.
In order to solve the problem that the penetration fuse circuit subjected to a large overload shock will produce circuit vibration noise, the mathematic model between the penetrating impact vibration excitation and the circuit vibration noise response has been established in the paper. And a noise elimination method based on wavelet analysis has been proposed. The method in the paper uses the wavelet transform to analyze the impact exciting signal of the penetration fuse and uses the Gaussian function to fit the output vibration noise response signal of circuit. Then the correlation function between these two signals can be established. The output noise processing algorithm of circuit is designed for vibration excitation based on this. The simulation results show that the algorithm has obvious de-noising effect on the noise of the penetration fuse circuit caused by impact vibration.
2018, 37(5): 747-752.
doi: 10.13433/j.cnki.1003-8728.2018.0515
Abstract:
To optimize the layout design of aircraft cockpit, research on operating of hand was conducted. Firstly, correlation between display device and control device in the cockpit was analyzed. Secondly, for the purpose of reducing length of hand operating route, layout optimization of cockpit man-machine interface was analyzed. Then, the mode of layout optimization based on hand operating comfort was established on the basis of geometry model of human hand and hand Kane dynamic model. Finally, simulation of hand operating route on man-machine interface was analyzed through practical case. Human hand operating gesture in the cockpit was simulated in the CATIA and joint angle data was obtained; Result was validated through CATIA module of comfort evaluation. The theoretical analysis and simulation results show that relatively important equipment should be arranged at the area that hand operation comfort is high, and length of hand operating route should be shorten as far as possible in the process of layout design. The model can improve the operating efficiency of driver and provide reference of cockpit layout design.
To optimize the layout design of aircraft cockpit, research on operating of hand was conducted. Firstly, correlation between display device and control device in the cockpit was analyzed. Secondly, for the purpose of reducing length of hand operating route, layout optimization of cockpit man-machine interface was analyzed. Then, the mode of layout optimization based on hand operating comfort was established on the basis of geometry model of human hand and hand Kane dynamic model. Finally, simulation of hand operating route on man-machine interface was analyzed through practical case. Human hand operating gesture in the cockpit was simulated in the CATIA and joint angle data was obtained; Result was validated through CATIA module of comfort evaluation. The theoretical analysis and simulation results show that relatively important equipment should be arranged at the area that hand operation comfort is high, and length of hand operating route should be shorten as far as possible in the process of layout design. The model can improve the operating efficiency of driver and provide reference of cockpit layout design.
2018, 37(5): 753-759.
doi: 10.13433/j.cnki.1003-8728.20180032
Abstract:
A kind of dynamic mixer with extrusion sheave and stirring impeller is designed to achieve uniform mixed performance for the short mixing time and different high viscosity liquids in vacuum state. The structure principle and mechanism about mixer are introduced. Mixture multiphase model, RNG κ-ε model and PISO algorithm are adopted in FLUENT software to obtain the simulation result for different outlet location of mixer premixed pipe, blades number, impeller speed. The results show that there are different mixing performance when the premixed pipe outlet location is changed, the mixer has its best mixing performance if the blades number is sixteen. The mixing performance has good effect as the rotational speed is increased at the same time, but the mixing performance will have steady state when it obtains certain speed. On this basis, the secondary shear effect from impeller and turbulence function of moving parts for flow field in mixer can accelerate liquid mix, according to the velocity vector of liquid particle, the distribution of flow streamline and the cloud chart of turbulent intensity contours. We choose Epoxy resin (E51) and the corresponding curing agent to mix for a mould, and the hardness of the production was tested. The experimental results show that this dynamic mixer has reliable mixing performance.
A kind of dynamic mixer with extrusion sheave and stirring impeller is designed to achieve uniform mixed performance for the short mixing time and different high viscosity liquids in vacuum state. The structure principle and mechanism about mixer are introduced. Mixture multiphase model, RNG κ-ε model and PISO algorithm are adopted in FLUENT software to obtain the simulation result for different outlet location of mixer premixed pipe, blades number, impeller speed. The results show that there are different mixing performance when the premixed pipe outlet location is changed, the mixer has its best mixing performance if the blades number is sixteen. The mixing performance has good effect as the rotational speed is increased at the same time, but the mixing performance will have steady state when it obtains certain speed. On this basis, the secondary shear effect from impeller and turbulence function of moving parts for flow field in mixer can accelerate liquid mix, according to the velocity vector of liquid particle, the distribution of flow streamline and the cloud chart of turbulent intensity contours. We choose Epoxy resin (E51) and the corresponding curing agent to mix for a mould, and the hardness of the production was tested. The experimental results show that this dynamic mixer has reliable mixing performance.
2018, 37(5): 760-766.
doi: 10.13433/j.cnki.1003-8728.20180073
Abstract:
In view of the existing high closure, difficult secondary development, complex structure, upgrade technology and other defects of industrial robot control system, a configurable modular industry robot motion control system is constructed based on LinuxCNC in this paper. On the premise of ensuring the stable operation of the robot, through the integration of real-time RTAI patch, robot control algorithm is programmed to real-time plan the robot motion control system. In order to verify the modular system architecture design can adapt to the operation requirements of different robot systems, a prototype system of industrial robot is used to verify the effectiveness and feasibility of the robot motion control system. According to the drive equipment and system requirements, the NC configuration file and communication configuration file is completed. The feasibility of the motion control system is verified by analyzing and processing the experimental data.
In view of the existing high closure, difficult secondary development, complex structure, upgrade technology and other defects of industrial robot control system, a configurable modular industry robot motion control system is constructed based on LinuxCNC in this paper. On the premise of ensuring the stable operation of the robot, through the integration of real-time RTAI patch, robot control algorithm is programmed to real-time plan the robot motion control system. In order to verify the modular system architecture design can adapt to the operation requirements of different robot systems, a prototype system of industrial robot is used to verify the effectiveness and feasibility of the robot motion control system. According to the drive equipment and system requirements, the NC configuration file and communication configuration file is completed. The feasibility of the motion control system is verified by analyzing and processing the experimental data.
2018, 37(5): 767-773.
doi: 10.13433/j.cnki.1003-8728.2018.0516
Abstract:
Aiming at the interference suppression assembly process of armature component, the elasto-plastic analyses are performed with computer simulation software ANSYS Workbench. The maximum equivalent stress and maximum press-mounting force on the interference suppression assembly of armature component are obtained. The influence rules of the interference value, friction coefficient and form error on the maximum equivalent stress and maximum press-mounting force are further studied for the interference suppression assemblies of armature components, then the rational scopes of interference values of armature components, and then the rational scopes of interference suppression curves of armature components are determined. The 18 kinds of armature components selected randomly were assembled with the press-mounting device developed. Comparing the computer simulation results with the experimental, the feasibility of the computer simulation method was verified. The analyzing results provide a theoretical basis for the press-mounting quality judgment of the interference suppression assembly of armature component.
Aiming at the interference suppression assembly process of armature component, the elasto-plastic analyses are performed with computer simulation software ANSYS Workbench. The maximum equivalent stress and maximum press-mounting force on the interference suppression assembly of armature component are obtained. The influence rules of the interference value, friction coefficient and form error on the maximum equivalent stress and maximum press-mounting force are further studied for the interference suppression assemblies of armature components, then the rational scopes of interference values of armature components, and then the rational scopes of interference suppression curves of armature components are determined. The 18 kinds of armature components selected randomly were assembled with the press-mounting device developed. Comparing the computer simulation results with the experimental, the feasibility of the computer simulation method was verified. The analyzing results provide a theoretical basis for the press-mounting quality judgment of the interference suppression assembly of armature component.
2018, 37(5): 774-780.
doi: 10.13433/j.cnki.1003-8728.2018.0517
Abstract:
A stochastic simulation method is proposed to analyze the quality robustness of a product whose quality index Y is influenced by aleatory and epistemic uncertainties. The epistemic uncertainty is characterized by the evidence theory, and then a random sampling method based on the random set theory is proposed for the epistemic uncertainty so that its random samples can be obtained according to its mass function. The aleatory uncertainty is directly sampled according to its probability distribution function, and it is not necessary for the aleatory uncertainty to be transformed into other types of uncertainty. By means of uncertainty analysis and computer simulation based on the above two random sampling methods, the uncertainty distribution of quality index Y is quantified by three statistical magnitudes of Y such as the width of mathematical expectation interval, the midpoint of expectation interval and the standard deviation of the subinterval midpoints. The above three statistical magnitudes are proposed as the evaluation indices of the quality robustness. For quality index Y with different characteristics, three different robust design criteria are put forward so that the robustness evaluation indices can be optimized. Finally, two typical examples prove that the proposed indices and criteria are rational and practical.
A stochastic simulation method is proposed to analyze the quality robustness of a product whose quality index Y is influenced by aleatory and epistemic uncertainties. The epistemic uncertainty is characterized by the evidence theory, and then a random sampling method based on the random set theory is proposed for the epistemic uncertainty so that its random samples can be obtained according to its mass function. The aleatory uncertainty is directly sampled according to its probability distribution function, and it is not necessary for the aleatory uncertainty to be transformed into other types of uncertainty. By means of uncertainty analysis and computer simulation based on the above two random sampling methods, the uncertainty distribution of quality index Y is quantified by three statistical magnitudes of Y such as the width of mathematical expectation interval, the midpoint of expectation interval and the standard deviation of the subinterval midpoints. The above three statistical magnitudes are proposed as the evaluation indices of the quality robustness. For quality index Y with different characteristics, three different robust design criteria are put forward so that the robustness evaluation indices can be optimized. Finally, two typical examples prove that the proposed indices and criteria are rational and practical.
2018, 37(5): 781-786.
doi: 10.13433/j.cnki.1003-8728.2018.0518
Abstract:
The imbalance test and control methods of a vehicle driveline system are studied, and the imbalance testing process is established. In the vehicle, the order separation method is used to determine the transmission gear, and the phase stabilization method is used to determine the balancing rotation speed in the first time. Then, the balance test mass and location are analyzed. The method is verified by the test data. Through analysis and calculation, it is pointed out that the imbalance mass of equivalent plane is mainly composed of component imbalance, assembly and cross-talking factors. The force vector synthesis shows that it can effectively improve the NVH problem of driveline imbalance with an equal angle bolt hole, control the composite flange run-out (CFRO) and match the light point and the heavy point. The measurement result shows that the control method is very effective.
The imbalance test and control methods of a vehicle driveline system are studied, and the imbalance testing process is established. In the vehicle, the order separation method is used to determine the transmission gear, and the phase stabilization method is used to determine the balancing rotation speed in the first time. Then, the balance test mass and location are analyzed. The method is verified by the test data. Through analysis and calculation, it is pointed out that the imbalance mass of equivalent plane is mainly composed of component imbalance, assembly and cross-talking factors. The force vector synthesis shows that it can effectively improve the NVH problem of driveline imbalance with an equal angle bolt hole, control the composite flange run-out (CFRO) and match the light point and the heavy point. The measurement result shows that the control method is very effective.
2018, 37(5): 787-791.
doi: 10.13433/j.cnki.1003-8728.2018.0519
Abstract:
An micro ablation model for C/C composites was built coupling the level set method with the diffusion equation to simulate the morphology evolution of C/C composites under high temperature condition. Surface morphology evolution during ablation was calculated. The cylindrical convex morphology resulted from calculation showed a good agreement with the surface morphologies of C/C composites after ablation experiment, indicating the reliability of the built model. On this basis, the effect of the gas diffusion and inhomogeneous oxidation reaction on the morphology evolutions of fibers and matrix were analyzed to support further studies on micro ablation mechanism of C/C composites.
An micro ablation model for C/C composites was built coupling the level set method with the diffusion equation to simulate the morphology evolution of C/C composites under high temperature condition. Surface morphology evolution during ablation was calculated. The cylindrical convex morphology resulted from calculation showed a good agreement with the surface morphologies of C/C composites after ablation experiment, indicating the reliability of the built model. On this basis, the effect of the gas diffusion and inhomogeneous oxidation reaction on the morphology evolutions of fibers and matrix were analyzed to support further studies on micro ablation mechanism of C/C composites.
2018, 37(5): 792-796.
doi: 10.13433/j.cnki.1003-8728.2018.0520
Abstract:
To explore the bonding effect of the polydimethylsiloxane(PDMS)substrate handled with different bonding time and bonding pressure after different process parameters of the plasma treatment. The three factor-four level-orthogonal tests and contrast tests was designed. The experimental results indicate that the sequence of the factors which organized by their influence is of:air flow rate > treatment time > radio frequency (RF)power. The parameters to get rapid irreversible bonding (Bonding 5 min) is:400 W, 2.5 L/min, 2 min. Under the middle or high RF power (300 W or higher), the bonding effects can meet the requirement with 10 h bonding. Under the low RF power (200 W or lower), the bonding effect can not meet the requirement after 24 hours. The bonding effect is significantly improved when the bonding pressure is more than 0.4 MPa.
To explore the bonding effect of the polydimethylsiloxane(PDMS)substrate handled with different bonding time and bonding pressure after different process parameters of the plasma treatment. The three factor-four level-orthogonal tests and contrast tests was designed. The experimental results indicate that the sequence of the factors which organized by their influence is of:air flow rate > treatment time > radio frequency (RF)power. The parameters to get rapid irreversible bonding (Bonding 5 min) is:400 W, 2.5 L/min, 2 min. Under the middle or high RF power (300 W or higher), the bonding effects can meet the requirement with 10 h bonding. Under the low RF power (200 W or lower), the bonding effect can not meet the requirement after 24 hours. The bonding effect is significantly improved when the bonding pressure is more than 0.4 MPa.
2018, 37(5): 797-803.
doi: 10.13433/j.cnki.1003-8728.2018.0521
Abstract:
In order to improve the machining accuracy and efficiency of the leading and the trailing edges(LTE) of aircraft engines blade, the existing problems in grinding of the current aircraft engines blade edges were analyzed, combined with the current requirements of machining technology for LTE and the motion control algorithms of computer numerical control(CNC) belt grinding machine, considering the influence of the grinding elements such as particle size, contact force, belt speed and feed rate, the tool trajectories are optimized, a grinding technology of the blade edges is put forward. Finally, the aircraft engines blades were subjected to actual grinding experiments. The experimental results show that the grinding method can obviously improve the machining precision and the surface roughness of the blade.
In order to improve the machining accuracy and efficiency of the leading and the trailing edges(LTE) of aircraft engines blade, the existing problems in grinding of the current aircraft engines blade edges were analyzed, combined with the current requirements of machining technology for LTE and the motion control algorithms of computer numerical control(CNC) belt grinding machine, considering the influence of the grinding elements such as particle size, contact force, belt speed and feed rate, the tool trajectories are optimized, a grinding technology of the blade edges is put forward. Finally, the aircraft engines blades were subjected to actual grinding experiments. The experimental results show that the grinding method can obviously improve the machining precision and the surface roughness of the blade.
2018, 37(5): 804-809.
doi: 10.13433/j.cnki.1003-8728.2018.0522
Abstract:
Clearance fit is a kind of common mechanical connection in engineering, it usually introduces uncertain connection stiffness. A parameter correction method with bushing element is proposed in the paper and a set of stiffness coefficients which suits for the finite element analysis of gas cylinder and its bracket assembly with gap feature is obtained. Firstly, the finite element model of gas cylinder and its bracket assembly is built, the bolt fastener and clearance fit are simulated by multi-point constraint element and bushing element, respectively. Secondly, the modeling method of the assembly is modified and the agreement between the modal analysis results and the test results with the original given stiffness coefficients of bushing element is verified. Finally, the stiffness coefficients are corrected with the adaptive response surface optimization method and their rationality is verified. The corrected coefficients are applied to the design of a new bracket. The analytical frequency results agree well with the test frequency results and the maximum deviation is less than 4.5%. Therefore, the veracity of the corrected coefficients and generality of the correction method are verified. A helpful reference is offered for the design and analysis of the similar structure.
Clearance fit is a kind of common mechanical connection in engineering, it usually introduces uncertain connection stiffness. A parameter correction method with bushing element is proposed in the paper and a set of stiffness coefficients which suits for the finite element analysis of gas cylinder and its bracket assembly with gap feature is obtained. Firstly, the finite element model of gas cylinder and its bracket assembly is built, the bolt fastener and clearance fit are simulated by multi-point constraint element and bushing element, respectively. Secondly, the modeling method of the assembly is modified and the agreement between the modal analysis results and the test results with the original given stiffness coefficients of bushing element is verified. Finally, the stiffness coefficients are corrected with the adaptive response surface optimization method and their rationality is verified. The corrected coefficients are applied to the design of a new bracket. The analytical frequency results agree well with the test frequency results and the maximum deviation is less than 4.5%. Therefore, the veracity of the corrected coefficients and generality of the correction method are verified. A helpful reference is offered for the design and analysis of the similar structure.
2018, 37(5): 810-815.
doi: 10.13433/j.cnki.1003-8728.2018.0523
Abstract:
To solve the tip diameter measurement of existing assembly clearance, easy clashing appearance, difficulty in fixation of aero-engine high pressure turbine rotor (HPTR) blades, a new process method is proposed by taking the adjacent left and right blade tips as the support reaction force points which externally support the measuring blade to eliminate the radial clearance. External support measurement device for HPTR blades is designed, and on the condition of high pressure turbine without dividing the rear baffle, the rotor blades are externally supported and fixed. The tip diameter measurement experiment for HPTR Blades is carried out and the measurement system accuracy is analyzed, whose the accuracy is 0.04 mm to meet the present measurement reqirement, which will lay an important foundation for developing the high precision tip diameter measuement instruments for aero-engine HPTR blades.
To solve the tip diameter measurement of existing assembly clearance, easy clashing appearance, difficulty in fixation of aero-engine high pressure turbine rotor (HPTR) blades, a new process method is proposed by taking the adjacent left and right blade tips as the support reaction force points which externally support the measuring blade to eliminate the radial clearance. External support measurement device for HPTR blades is designed, and on the condition of high pressure turbine without dividing the rear baffle, the rotor blades are externally supported and fixed. The tip diameter measurement experiment for HPTR Blades is carried out and the measurement system accuracy is analyzed, whose the accuracy is 0.04 mm to meet the present measurement reqirement, which will lay an important foundation for developing the high precision tip diameter measuement instruments for aero-engine HPTR blades.
2018, 37(5): 816-820.
doi: 10.13433/j.cnki.1003-8728.20180021
Abstract:
The method of natural mesh and refined model for structural analysis is considered based on experimental data. Natural mesh method is employed to build a wing-body FEM model, which results in a relative error 7.46% of wing-tip displacement. The relative error between analysis and test results which are within 10% takes up about 80% of whole points on upper panel of outer wing; whereas, it takes up about 70% on upper panel of central wing. Shell elements are mainly used to establish a refined model for a full-scale aircraft, which obtains the relative error 1.87% of wing-tip displacement. The relative error between analysis and test results which are with 10% takes up over 80% on upper panels of central and outer wing. The results show that the refined model can accurately simulate the stiffness, load distribution and global stress/strain response. Therefore, the refined model could also be used to predict zones of interest for more detailed analysis, and provide the failure boundarys.
The method of natural mesh and refined model for structural analysis is considered based on experimental data. Natural mesh method is employed to build a wing-body FEM model, which results in a relative error 7.46% of wing-tip displacement. The relative error between analysis and test results which are within 10% takes up about 80% of whole points on upper panel of outer wing; whereas, it takes up about 70% on upper panel of central wing. Shell elements are mainly used to establish a refined model for a full-scale aircraft, which obtains the relative error 1.87% of wing-tip displacement. The relative error between analysis and test results which are with 10% takes up over 80% on upper panels of central and outer wing. The results show that the refined model can accurately simulate the stiffness, load distribution and global stress/strain response. Therefore, the refined model could also be used to predict zones of interest for more detailed analysis, and provide the failure boundarys.
