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RSS2012 Vol. 31, No. 3
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2012, 31(3): 345-349.
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Abstract:
Lubrication is related to the adhesive power(Wa) of lubricating fluid on solid surface.In this paper,the surface tension(γL) and the contact angle(θ) of the different HCT bloods on three bio-titanium alloys(TA2,TC4,TLM) surface which have different roughness through the experiment is summarized.The lubrication and action mechanism of the blood to the biological titanium alloy surface has also been studied.The experimental results showed that the bigger the blood's HCT,the better the lubrication to the alloy surface is,and the rougher alloy surfaces,the better lubrication of the blood on their surface at the micron range of Rais.The lubrication of the blood to TLM titanium alloys is the best,and that to TA2 titanium is the worst,and that to TC4 titanium is moderate.
Lubrication is related to the adhesive power(Wa) of lubricating fluid on solid surface.In this paper,the surface tension(γL) and the contact angle(θ) of the different HCT bloods on three bio-titanium alloys(TA2,TC4,TLM) surface which have different roughness through the experiment is summarized.The lubrication and action mechanism of the blood to the biological titanium alloy surface has also been studied.The experimental results showed that the bigger the blood's HCT,the better the lubrication to the alloy surface is,and the rougher alloy surfaces,the better lubrication of the blood on their surface at the micron range of Rais.The lubrication of the blood to TLM titanium alloys is the best,and that to TA2 titanium is the worst,and that to TC4 titanium is moderate.
2012, 31(3): 350-352.
Abstract:
Underwater launching aircraft is a new unmanned aircraft which is carried,launched by an underwater vehicle,then moves in and exit the water,and flies in air eventually.For the hood separation of underwater launching aircraft,we proposed a separation design approach using circumferential and radial collocated cutting blasting considering the requirements of reliability and security.The mathematical model of the hood separation is established to calculate the hood separation characteristics and to predict the trajectory of separated bodies.The present study provides the necessary theoretical basis to the design of underwater launching aircraft.
Underwater launching aircraft is a new unmanned aircraft which is carried,launched by an underwater vehicle,then moves in and exit the water,and flies in air eventually.For the hood separation of underwater launching aircraft,we proposed a separation design approach using circumferential and radial collocated cutting blasting considering the requirements of reliability and security.The mathematical model of the hood separation is established to calculate the hood separation characteristics and to predict the trajectory of separated bodies.The present study provides the necessary theoretical basis to the design of underwater launching aircraft.
2012, 31(3): 353-358.
Abstract:
Aimed at the assembly sequence planning problem,a discrete electromangnetism-like mechanism algorithm is proposed.Firstly,a connector-based conception is introduced,and according to the attributes of connectors,directions of assembly and assembly tools,the similarity matrix is constructed.Then the objective function founded on maximum similarity is defined.By redefining the distance and movement of solutions,initiating the memorable mechanism,the calculating formulas of charge and force are improved and discretized to solve the assembly sequence planning problem.
Aimed at the assembly sequence planning problem,a discrete electromangnetism-like mechanism algorithm is proposed.Firstly,a connector-based conception is introduced,and according to the attributes of connectors,directions of assembly and assembly tools,the similarity matrix is constructed.Then the objective function founded on maximum similarity is defined.By redefining the distance and movement of solutions,initiating the memorable mechanism,the calculating formulas of charge and force are improved and discretized to solve the assembly sequence planning problem.
2012, 31(3): 359-362.
Abstract:
The existing quad-rotor helicopter control systems have problems of weak robustness and low control precision,in this paper,PD(proportion-differentiation) control algorithm is proposed based on the existing models to improve the robustness.Firstly,a model for the quad-rotor helicopter is established and the principle of quad-rotor helicopter flight controlling is described.Then,quad-rotor helicopter control system is designed according to the principle of quad-rotor helicopter flight,the design of control system includes the design of hardware module and control codes.PD control algorithm is employed in helicopter attitude feedback control.Finally,the principle of quad-rotor helicopter flight and the performance of the control system based on PD algorithm are validated by experiments on "micro-shadow" I and "micro-shadow" II prototypes,the results show that the robustness of the quad-rotor helicopter control system based on PD algorithm is improved.
The existing quad-rotor helicopter control systems have problems of weak robustness and low control precision,in this paper,PD(proportion-differentiation) control algorithm is proposed based on the existing models to improve the robustness.Firstly,a model for the quad-rotor helicopter is established and the principle of quad-rotor helicopter flight controlling is described.Then,quad-rotor helicopter control system is designed according to the principle of quad-rotor helicopter flight,the design of control system includes the design of hardware module and control codes.PD control algorithm is employed in helicopter attitude feedback control.Finally,the principle of quad-rotor helicopter flight and the performance of the control system based on PD algorithm are validated by experiments on "micro-shadow" I and "micro-shadow" II prototypes,the results show that the robustness of the quad-rotor helicopter control system based on PD algorithm is improved.
2012, 31(3): 363-366.
Abstract:
The three dimensional mixed-mode surface cracks usually occurrs in engineering complicated structure,and to study on the three dimensional mixed-mode surface cracks is useful to perfect assess technique of three dimensional damage tolerance.In this paper,S-FEM is applied to solve stress intensity factors for inclined mixed mode surface cracks in finite body.The effect of inclination angles and crack shape on the mixed mode fracture solution was discussed in detail.It is shown that mode I stress intensity factors decreased in magnitude along the whole crack front as the inclination angle increases.Mode II and mode III stress intensity factors,on the other hand,increased initially as the inclination angle increases and then decreased for higher inclination angles.It is also shown that maximum stress intensity factors of a surface crack usually appear at the deepest point of the crack,or a certain point along crack front near the free surface depending on the aspect ratio of the crack.The results can be referred for mixed mode damage tolerance analysis of 3-D structure in engineering.
The three dimensional mixed-mode surface cracks usually occurrs in engineering complicated structure,and to study on the three dimensional mixed-mode surface cracks is useful to perfect assess technique of three dimensional damage tolerance.In this paper,S-FEM is applied to solve stress intensity factors for inclined mixed mode surface cracks in finite body.The effect of inclination angles and crack shape on the mixed mode fracture solution was discussed in detail.It is shown that mode I stress intensity factors decreased in magnitude along the whole crack front as the inclination angle increases.Mode II and mode III stress intensity factors,on the other hand,increased initially as the inclination angle increases and then decreased for higher inclination angles.It is also shown that maximum stress intensity factors of a surface crack usually appear at the deepest point of the crack,or a certain point along crack front near the free surface depending on the aspect ratio of the crack.The results can be referred for mixed mode damage tolerance analysis of 3-D structure in engineering.
2012, 31(3): 367-372.
Abstract:
The nonlinear dynamics model of the crankshaft system including 6 linkages,6 pistons and one propeller is established with the consideration of alternate moment of inertia of the linkages and pistons,and the coupling effect between torsional and axial vibration.The governing equations represent a strong nonlinear and non autonomous system.By numeric simulation,the response of the system to the initial displacement and velocity,the variable moment of inertia,the pressure applied on the piston,torque and axial force applied on the propeller is analyzed individually.It is found that the variable moment of inertia and coupling effect between torsional and axial vibration is the essential reason for nonlinear vibration of the system.Different exciting factors can not only cause different frequency components,but also different amplitude for the same frequency component.Under the special conditions in the paper,the dynamic characteristics of the system is not influenced distinctively by the actuating torque and axial force applied on the propeller.The sensitivity of the response in different direction to the same exciting factor is clearly different.
The nonlinear dynamics model of the crankshaft system including 6 linkages,6 pistons and one propeller is established with the consideration of alternate moment of inertia of the linkages and pistons,and the coupling effect between torsional and axial vibration.The governing equations represent a strong nonlinear and non autonomous system.By numeric simulation,the response of the system to the initial displacement and velocity,the variable moment of inertia,the pressure applied on the piston,torque and axial force applied on the propeller is analyzed individually.It is found that the variable moment of inertia and coupling effect between torsional and axial vibration is the essential reason for nonlinear vibration of the system.Different exciting factors can not only cause different frequency components,but also different amplitude for the same frequency component.Under the special conditions in the paper,the dynamic characteristics of the system is not influenced distinctively by the actuating torque and axial force applied on the propeller.The sensitivity of the response in different direction to the same exciting factor is clearly different.
2012, 31(3): 373-378.
Abstract:
Optimizing the complicated structures,the traditional design method could lead to local optimal solution,and consume the large amount time of calculation.The response surface method is one of the effective methods to solve this problem.In this paper,the optimization of the bracket structure with the software platform of Altair was described.Parameterized modeling,design of experiments,approximations and optimization were integrated and performed.Main effects of different design variables on the responses were analyzed and an optimization with response surface method was implemented.The data show the optimized structure achieves the design requirements.The design efficiency will be improved.
Optimizing the complicated structures,the traditional design method could lead to local optimal solution,and consume the large amount time of calculation.The response surface method is one of the effective methods to solve this problem.In this paper,the optimization of the bracket structure with the software platform of Altair was described.Parameterized modeling,design of experiments,approximations and optimization were integrated and performed.Main effects of different design variables on the responses were analyzed and an optimization with response surface method was implemented.The data show the optimized structure achieves the design requirements.The design efficiency will be improved.
2012, 31(3): 379-383.
Abstract:
To evaluate the performance of a car,people are ambiguous,they often consider a particular aspect performance of the vehicle is good or not.There is not a good method to compare the different types of vehicles,particular the performance of the vehicle.In this paper,the research work is to get a method to evaluate the performance of the vehicle.By considering the requirements of the user together with car classification,the weighting coefficients of performance of various vehicles were determined,then the evaluation equation for vehicle performance was obtained.Using this method,one can match the interrelated performance of vehicles and known how to improve the vehicle design.
To evaluate the performance of a car,people are ambiguous,they often consider a particular aspect performance of the vehicle is good or not.There is not a good method to compare the different types of vehicles,particular the performance of the vehicle.In this paper,the research work is to get a method to evaluate the performance of the vehicle.By considering the requirements of the user together with car classification,the weighting coefficients of performance of various vehicles were determined,then the evaluation equation for vehicle performance was obtained.Using this method,one can match the interrelated performance of vehicles and known how to improve the vehicle design.
2012, 31(3): 384-387.
Abstract:
Refrigeration has been the key issue for the development of high heat flux laser for a long time,because it is hard for the heat dissipation capability of traditional cooling methods to breakthrough 100 W/cm2.A couple of liquid cooling micro-channel radiators with water as medium are introduced in this paper,and the structure of cold plates based on V-groove is studied mainly.The influences of the inlet velocity,width of the micro-channel and ratio of the channel width to the rib on the heat transfer efficiency are simulated by finite element software.The position of branch manifold is further optimized to improve the uniformity of the maximum surface temperature distribution.It is shown that the heat sink capability of liquid cooling micro-channel radiators with V-groove cold plates could be up to 500 W/cm2.
Refrigeration has been the key issue for the development of high heat flux laser for a long time,because it is hard for the heat dissipation capability of traditional cooling methods to breakthrough 100 W/cm2.A couple of liquid cooling micro-channel radiators with water as medium are introduced in this paper,and the structure of cold plates based on V-groove is studied mainly.The influences of the inlet velocity,width of the micro-channel and ratio of the channel width to the rib on the heat transfer efficiency are simulated by finite element software.The position of branch manifold is further optimized to improve the uniformity of the maximum surface temperature distribution.It is shown that the heat sink capability of liquid cooling micro-channel radiators with V-groove cold plates could be up to 500 W/cm2.
2012, 31(3): 388-391.
Abstract:
In reverse engineering,quality evaluation of class A surfaces is the key segment of auto-body smoothing.Based on the fuzzy analytic hierarchy process(FAHP),in combination with quality requirement of class A surfaces and judgment rules of smoothing engineering,the evaluation rules of class A surfaces are presented in this paper,surfaces evaluation model were built,and the comprehensive system of evaluation is given.At last,taking the quality evaluation of a smoothed auto body rear back as a practical example,a comprehensive evaluation was provided to this model.The result verified that class A surfaces can be evaluated efficiently by FAHP.
In reverse engineering,quality evaluation of class A surfaces is the key segment of auto-body smoothing.Based on the fuzzy analytic hierarchy process(FAHP),in combination with quality requirement of class A surfaces and judgment rules of smoothing engineering,the evaluation rules of class A surfaces are presented in this paper,surfaces evaluation model were built,and the comprehensive system of evaluation is given.At last,taking the quality evaluation of a smoothed auto body rear back as a practical example,a comprehensive evaluation was provided to this model.The result verified that class A surfaces can be evaluated efficiently by FAHP.
2012, 31(3): 392-396.
Abstract:
Polygon effect of saw chain system is a major factor of the unstableness of oil saw chain drive,which will cause impact,dynamic load,noise and dithering of saw chain.A new method is presented in this paper for the dynamics analysis on polygon effect of oil saw chain system.With appropriate simplifications of the oil saw chain system,dynamics on polygon effect of oil saw chain system is analyzed by using difference method of numerical approximation,and a Matlab program is designed accordingly,and then the varying curves of parameters such as speed and dynamic load are obtained in one period.Compared with results obtained by using traditional methods available in textbook,it is shown that the proposed new method is more appropriate for dynamics analysis on polygon effect of oil saw chain system.
Polygon effect of saw chain system is a major factor of the unstableness of oil saw chain drive,which will cause impact,dynamic load,noise and dithering of saw chain.A new method is presented in this paper for the dynamics analysis on polygon effect of oil saw chain system.With appropriate simplifications of the oil saw chain system,dynamics on polygon effect of oil saw chain system is analyzed by using difference method of numerical approximation,and a Matlab program is designed accordingly,and then the varying curves of parameters such as speed and dynamic load are obtained in one period.Compared with results obtained by using traditional methods available in textbook,it is shown that the proposed new method is more appropriate for dynamics analysis on polygon effect of oil saw chain system.
2012, 31(3): 397-401.
Abstract:
For the study of life sciences,bio-manipulation faces such challenges as long time for operator training,low success rate,low efficiency,operation inconsistency and repetition.We believe that automatic bio-manipulation can solve these challenges.We integrate several commercial devices and use the matrix that maps the visual system with the robotic system to derive the error correction equation.We also use the local recurrence and global optimization calibration method to reduce the target point's positioning error.On this basis,using the Kalman filter,we establish the systems' control equations to control the precise positioning of the bio-manipulation probe.Finally,we implement the algorithm theory and integrate the algorithm with the drive modules of other devices,thus establishing a flexible and user-friendly software system.The experimental results show that the algorithm theory and software systems thus integrated can automatically control the probe's accurate motion,the motion accuracy being within one pixel.
For the study of life sciences,bio-manipulation faces such challenges as long time for operator training,low success rate,low efficiency,operation inconsistency and repetition.We believe that automatic bio-manipulation can solve these challenges.We integrate several commercial devices and use the matrix that maps the visual system with the robotic system to derive the error correction equation.We also use the local recurrence and global optimization calibration method to reduce the target point's positioning error.On this basis,using the Kalman filter,we establish the systems' control equations to control the precise positioning of the bio-manipulation probe.Finally,we implement the algorithm theory and integrate the algorithm with the drive modules of other devices,thus establishing a flexible and user-friendly software system.The experimental results show that the algorithm theory and software systems thus integrated can automatically control the probe's accurate motion,the motion accuracy being within one pixel.
2012, 31(3): 402-406.
Abstract:
This paper analyses the needs for dynamic alliance to do its task decomposition and then proposes a fuzzy clustering algorithm which clusters the task from enterprise layer to subprojects in alliance layer.It assigns values to the degrees of closeness of relationship among task modules according to the numbers 1 through 9 T and then creates the adjacency matrices of the modules.It then sets different thresholds to perform the fuzzy clustering of the adjacency matrices.It uses the clustering degree among task modules and the separation degree between them as the values of adaptiveness function to calculate the value of the adaptiveness function at each threshold value.It finally obtains the best scheme of task module decomposition with the best clustering threshold value when the value of the adaptiveness function is maximum.
This paper analyses the needs for dynamic alliance to do its task decomposition and then proposes a fuzzy clustering algorithm which clusters the task from enterprise layer to subprojects in alliance layer.It assigns values to the degrees of closeness of relationship among task modules according to the numbers 1 through 9 T and then creates the adjacency matrices of the modules.It then sets different thresholds to perform the fuzzy clustering of the adjacency matrices.It uses the clustering degree among task modules and the separation degree between them as the values of adaptiveness function to calculate the value of the adaptiveness function at each threshold value.It finally obtains the best scheme of task module decomposition with the best clustering threshold value when the value of the adaptiveness function is maximum.
2012, 31(3): 407-411.
Abstract:
A new kind of wave-tape roller mill is proposed in this paper and the general designing principles of the wave-type roller is discussed.The present study focus on the design of wave-type roller geometrical curve,nip angle and gap changes.Through geometrical calculated,the wave-typeroller geometrical curve function expression is obtained.The changes of wave-type roller nip angle and gap are studied by combining CAD simulation and Matlab curve fitting,it is concluded that wave-type roller nip angle and gap varies along with the cyclical change of wave-type roller rotation,the average nip angle of wave-type roller is smaller than common cylindrical roller nip angle and wave-type roller mill has higher production efficiency than common cylindrical roll crusher.Compared with common cylindrical roll crusher and tube roller mill,wave-type roller mill has its own advantages.
A new kind of wave-tape roller mill is proposed in this paper and the general designing principles of the wave-type roller is discussed.The present study focus on the design of wave-type roller geometrical curve,nip angle and gap changes.Through geometrical calculated,the wave-typeroller geometrical curve function expression is obtained.The changes of wave-type roller nip angle and gap are studied by combining CAD simulation and Matlab curve fitting,it is concluded that wave-type roller nip angle and gap varies along with the cyclical change of wave-type roller rotation,the average nip angle of wave-type roller is smaller than common cylindrical roller nip angle and wave-type roller mill has higher production efficiency than common cylindrical roll crusher.Compared with common cylindrical roll crusher and tube roller mill,wave-type roller mill has its own advantages.
2012, 31(3): 412-416.
Abstract:
It is difficut to analyze the ball end milling process because of the complex multi-physics coupling and the particularity of the ball end milling cutter.A cutting finite model of ball end milling is established in Deform 3D pre-processor.And reliable material model,cutting separation principles,reasonable friction model,appropriate boundary conditions are also used in this model.Then the results comprise the milling force,temperature field and residual stress field.They have shown the effect of cutting speed,cutting depth,feed speed on the temperature and residual stress field.The present results has great reference for further research of ball end milling process and optimization of the machining method.
It is difficut to analyze the ball end milling process because of the complex multi-physics coupling and the particularity of the ball end milling cutter.A cutting finite model of ball end milling is established in Deform 3D pre-processor.And reliable material model,cutting separation principles,reasonable friction model,appropriate boundary conditions are also used in this model.Then the results comprise the milling force,temperature field and residual stress field.They have shown the effect of cutting speed,cutting depth,feed speed on the temperature and residual stress field.The present results has great reference for further research of ball end milling process and optimization of the machining method.
2012, 31(3): 417-423.
Abstract:
With the multiple-attribute decision-making model,we convert the hierarchical structure of multiple-attribute decision making into the Bayesian Network structure from binary state to multiple states,thus reducing the complexity of the hierarchical structure.Then,we calculate the conditional probabilities of the nodes of the Bayesian Network,using the fuzzy relational matrix of the grade field of the fuzzy comprehensive evaluation indexes and the attribute weights.We also analyze the importance of the Bayesian network nodes.Finally,we verify the effectiveness of the multiple-attribute decision-making model by comparing the application example from our research project with the hierarchical analysis method.The comparison results show that our multiple-attribute decision-making model can not only select one optimal scheme and determine its state by calculating the degree of closeness to the ideal solution but also find out the bottleneck that affects the optimal scheme by doing the importance analysis.
With the multiple-attribute decision-making model,we convert the hierarchical structure of multiple-attribute decision making into the Bayesian Network structure from binary state to multiple states,thus reducing the complexity of the hierarchical structure.Then,we calculate the conditional probabilities of the nodes of the Bayesian Network,using the fuzzy relational matrix of the grade field of the fuzzy comprehensive evaluation indexes and the attribute weights.We also analyze the importance of the Bayesian network nodes.Finally,we verify the effectiveness of the multiple-attribute decision-making model by comparing the application example from our research project with the hierarchical analysis method.The comparison results show that our multiple-attribute decision-making model can not only select one optimal scheme and determine its state by calculating the degree of closeness to the ideal solution but also find out the bottleneck that affects the optimal scheme by doing the importance analysis.
2012, 31(3): 424-428.
Abstract:
To improve the access efficiency of medium and small items storage system,shorten storage time and enhance the accuracy of store operations in Automatic Storage and Retrieval System(AS/RS),the Picking Path of two-station carousel was studied and optimized by the particle swarm algorithm.After analyzing the picking process,a mathematical model is proposed to solve the problem of picking path optimization.Aiming at the model,the method is designed based on the particle swarm algorithm and it is proved to be effective.The simulation results proves that the particle swarm algorithm can solve the picking path optimization of two-station carousel fastly,stably and efficiently,thus promote the whole operation efficiency of automated warehouse.
To improve the access efficiency of medium and small items storage system,shorten storage time and enhance the accuracy of store operations in Automatic Storage and Retrieval System(AS/RS),the Picking Path of two-station carousel was studied and optimized by the particle swarm algorithm.After analyzing the picking process,a mathematical model is proposed to solve the problem of picking path optimization.Aiming at the model,the method is designed based on the particle swarm algorithm and it is proved to be effective.The simulation results proves that the particle swarm algorithm can solve the picking path optimization of two-station carousel fastly,stably and efficiently,thus promote the whole operation efficiency of automated warehouse.
2012, 31(3): 429-432.
Abstract:
To obtain production capacity parameters from assembly workshop,a method for the production capacity of aircraft assembly project based on disassembling circumfluence of Petri model was proposed.First,according to definitions of P/T system and assembly station,the Petri model of assembly station was established by mapping `function for key elements.Through original state setting of and assembly Petri net,and a method of solving production capacity based on the view of net circumfluence was discussed.Finally,the application of the aircraft assembly field were introduced,and applied to demonstrate the functionality of this method.
To obtain production capacity parameters from assembly workshop,a method for the production capacity of aircraft assembly project based on disassembling circumfluence of Petri model was proposed.First,according to definitions of P/T system and assembly station,the Petri model of assembly station was established by mapping `function for key elements.Through original state setting of and assembly Petri net,and a method of solving production capacity based on the view of net circumfluence was discussed.Finally,the application of the aircraft assembly field were introduced,and applied to demonstrate the functionality of this method.
2012, 31(3): 433-436.
Abstract:
In this paper a common integrated exciting system is designed for the universal integrated avionics systems,primarily in the system design and management,software development and bus information stream management.Firstly we describe the basic principles which must be followed by the system design,the basic structure and function of the exciting system to be designed.Then we explain the hardware configuration of the system and finally we describe the software design ideas,and give some explanation of the software configuration and design process for each subsystem.Application examples destrated that the designed system in the paper is highly versatile and it can satisfy the needs for various types of simulations.
In this paper a common integrated exciting system is designed for the universal integrated avionics systems,primarily in the system design and management,software development and bus information stream management.Firstly we describe the basic principles which must be followed by the system design,the basic structure and function of the exciting system to be designed.Then we explain the hardware configuration of the system and finally we describe the software design ideas,and give some explanation of the software configuration and design process for each subsystem.Application examples destrated that the designed system in the paper is highly versatile and it can satisfy the needs for various types of simulations.
2012, 31(3): 437-441.
Abstract:
We establish the mathematical model of a multi-wire tension control system and design an adaptive control algorithm for the control of the wire tension.The adaptive control algorithm uses the NLMS(normalized least mean squares) algorithm to perform the adaptive and dynamic correction of the rotational speed of the multi-wire saw with the rotational speed and angle fed back by the tension control motor so as to control the wire tension more accurately.The Matlab simulation results show that our adaptive control algorithm can accurately control the wire tension of the multi-wire saw.
We establish the mathematical model of a multi-wire tension control system and design an adaptive control algorithm for the control of the wire tension.The adaptive control algorithm uses the NLMS(normalized least mean squares) algorithm to perform the adaptive and dynamic correction of the rotational speed of the multi-wire saw with the rotational speed and angle fed back by the tension control motor so as to control the wire tension more accurately.The Matlab simulation results show that our adaptive control algorithm can accurately control the wire tension of the multi-wire saw.
2012, 31(3): 442-445.
Abstract:
Aiming at the city bus characteristics of low speed operation and frequent start and stop conditions,an electro-mechanical braking energy regeneration system was proposed in this paper,which adopted a high-speed flywheel and a battery to recover the braking energy and achieve the secondary traction for the auxiliary start function.The system was designed and the braking simulation validated its feasibility.The experiment results show that the system can effectively recover the braking energy,improve the starting performance of the bus and it will be applied to city bus engineering in the future.
Aiming at the city bus characteristics of low speed operation and frequent start and stop conditions,an electro-mechanical braking energy regeneration system was proposed in this paper,which adopted a high-speed flywheel and a battery to recover the braking energy and achieve the secondary traction for the auxiliary start function.The system was designed and the braking simulation validated its feasibility.The experiment results show that the system can effectively recover the braking energy,improve the starting performance of the bus and it will be applied to city bus engineering in the future.
2012, 31(3): 446-451.
Abstract:
We design a vehicle adaptive cruise control(ACC) system that has active safety,using the finite state machine(FSM) theory and the fuzzy logic control theory.First,we establish the model of the vehicle's power transmission system.Then we simulate the control of the throttle angle and brake pressure of the ACC system.The simulation results show that the ACC system thus designed controlled can make the vehicle automatically switch into the finite state and follow the desired acceleration command and that the ACC system can provide such satisfactory performances as acceleration,vehicle tracking and braking.
We design a vehicle adaptive cruise control(ACC) system that has active safety,using the finite state machine(FSM) theory and the fuzzy logic control theory.First,we establish the model of the vehicle's power transmission system.Then we simulate the control of the throttle angle and brake pressure of the ACC system.The simulation results show that the ACC system thus designed controlled can make the vehicle automatically switch into the finite state and follow the desired acceleration command and that the ACC system can provide such satisfactory performances as acceleration,vehicle tracking and braking.
2012, 31(3): 452-455,460.
Abstract:
Ageing forming is one of best techniques to form high precision panel.This technical characteristic includes large springback and difficult-to-control of precision,so as to be applied in practice.In this paper,the key problems in the ageing forming of integral panel with high ribs are studied.The springback rules is studied through the T-style panels of 2124 aluminium alloy,the springback compensation of mold surface is calculated using a geometrical compensation algorithm.The experimental results is that the error in curved surface is less than 1.0 mm and that in rib of integral panel is less than 0.5 mm.Those results show that the method is feasible and effective.
Ageing forming is one of best techniques to form high precision panel.This technical characteristic includes large springback and difficult-to-control of precision,so as to be applied in practice.In this paper,the key problems in the ageing forming of integral panel with high ribs are studied.The springback rules is studied through the T-style panels of 2124 aluminium alloy,the springback compensation of mold surface is calculated using a geometrical compensation algorithm.The experimental results is that the error in curved surface is less than 1.0 mm and that in rib of integral panel is less than 0.5 mm.Those results show that the method is feasible and effective.
2012, 31(3): 456-460.
Abstract:
The scraper conveyor is heavy machinery which can continuously transport goods.The failure,which occurs in use and run,will seriously affect the production cost and production capacity,so the prediction of scraper reliability is very important to factories,mines and other enterprises.In this paper,the failure factors of scraper parts are classified and discussed,parts are grouped to research the scraper reliability.The age distribution law and the structural stress law of machine parts are studied during operation and service course,and the simulation models of scraper reliability are established undergoing the maintenance.Finally,the scraper reliability is calculated,which will provide a strong basis for enterprises evaluation of production costs and capacity.
The scraper conveyor is heavy machinery which can continuously transport goods.The failure,which occurs in use and run,will seriously affect the production cost and production capacity,so the prediction of scraper reliability is very important to factories,mines and other enterprises.In this paper,the failure factors of scraper parts are classified and discussed,parts are grouped to research the scraper reliability.The age distribution law and the structural stress law of machine parts are studied during operation and service course,and the simulation models of scraper reliability are established undergoing the maintenance.Finally,the scraper reliability is calculated,which will provide a strong basis for enterprises evaluation of production costs and capacity.
2012, 31(3): 461-464,469.
Abstract:
The symmetric composite laminates with thermal residual stress possess bi-stable property.This property makes structures have two stable configurations.The benefit of bi-stable structure is that the stable shapes are operational shapes,and power is needed only to transform the structure from one to another shape.In this paper,the reason of thermal stress formation was simply demonstrated.And the potential energy function with thermal residual stress was established based on the classic laminate theory.Thus,the methodical expression of interpolation function was given,and the bi-stable mechanism of composite laminates was demonstrated in detail.Therefore the numerical simulation of two asymmetric bi-stable composite laminates was carried out using the finite-element package ANSYS.So the mechanism demonstrated was proved to be accredited.
The symmetric composite laminates with thermal residual stress possess bi-stable property.This property makes structures have two stable configurations.The benefit of bi-stable structure is that the stable shapes are operational shapes,and power is needed only to transform the structure from one to another shape.In this paper,the reason of thermal stress formation was simply demonstrated.And the potential energy function with thermal residual stress was established based on the classic laminate theory.Thus,the methodical expression of interpolation function was given,and the bi-stable mechanism of composite laminates was demonstrated in detail.Therefore the numerical simulation of two asymmetric bi-stable composite laminates was carried out using the finite-element package ANSYS.So the mechanism demonstrated was proved to be accredited.
2012, 31(3): 465-469.
Abstract:
In order to improve the kinematic accuracy of a six-axis hybrid machine tool,we study its 3-RPS parallel mechanism,analyze the geometric errors that influence its reachable space and establish its attitude error model.We use the ADAMS virtual prototyping software to construct the kinematics model of the parallel mechanism that includes all parameters of geometric errors and to simulate the effects of the major geometric errors on the kinematic accuracy of the parallel mechanism.According to the simulation results,we evaluate the mapping of all its geometric errors,including those of error source and workspace.
In order to improve the kinematic accuracy of a six-axis hybrid machine tool,we study its 3-RPS parallel mechanism,analyze the geometric errors that influence its reachable space and establish its attitude error model.We use the ADAMS virtual prototyping software to construct the kinematics model of the parallel mechanism that includes all parameters of geometric errors and to simulate the effects of the major geometric errors on the kinematic accuracy of the parallel mechanism.According to the simulation results,we evaluate the mapping of all its geometric errors,including those of error source and workspace.
2012, 31(3): 470-474,479.
Abstract:
The sound generation characteristics for the low-frequency airflow modulators are studied based on the simple sound source theory in this paper.The calculation formulas for three types of airflow modulators,with flexing square hole,rotating square hole and rotating circular hole are deduced,respectively.The sound generation laws for the rotating square hole modulator due to the changes of the duty cycle,gas chamber volume,gas supply pressure and flow rate are calculated based on the simple sound source theory.The simple sound source characteristics of such three modulators are compared.The calculation results show that the distortion of the flexing square hole modulator is the minimum and the highest sound intensity and the minimum distortion can be realized by choosing proper duty cycle.The bigger the gas chamber volume,gas supply pressure and flow rate are,the higher the sound intensity is.but the incremental ratio is decreased and the distortion is augmented at first and then decreased.The comprehensive consideration of these factors is beneficial to the design and optimization of the airflow modulator.
The sound generation characteristics for the low-frequency airflow modulators are studied based on the simple sound source theory in this paper.The calculation formulas for three types of airflow modulators,with flexing square hole,rotating square hole and rotating circular hole are deduced,respectively.The sound generation laws for the rotating square hole modulator due to the changes of the duty cycle,gas chamber volume,gas supply pressure and flow rate are calculated based on the simple sound source theory.The simple sound source characteristics of such three modulators are compared.The calculation results show that the distortion of the flexing square hole modulator is the minimum and the highest sound intensity and the minimum distortion can be realized by choosing proper duty cycle.The bigger the gas chamber volume,gas supply pressure and flow rate are,the higher the sound intensity is.but the incremental ratio is decreased and the distortion is augmented at first and then decreased.The comprehensive consideration of these factors is beneficial to the design and optimization of the airflow modulator.
2012, 31(3): 475-479.
Abstract:
The diagnostic instrument manipulator(DIM) for the instruments pointing and positioning in inertial confinement fusion(ICF) is introduced.The DIM is a 3 degree of freedom(DOF) hybrid manipulator,and its structure and working principle are introduced in this paper.The close-form inverse kinematics of the manipulator's end is presented.Moreover,the error model of the reset accuracy is formulated,based on the relationship between the end's deformation and the gravity center of the inner tube.According to the deviation between the calculation error and measurement error fluctuating within a small range,a compensation coefficient can be found to compensate the accuracy of the original motion.
The diagnostic instrument manipulator(DIM) for the instruments pointing and positioning in inertial confinement fusion(ICF) is introduced.The DIM is a 3 degree of freedom(DOF) hybrid manipulator,and its structure and working principle are introduced in this paper.The close-form inverse kinematics of the manipulator's end is presented.Moreover,the error model of the reset accuracy is formulated,based on the relationship between the end's deformation and the gravity center of the inner tube.According to the deviation between the calculation error and measurement error fluctuating within a small range,a compensation coefficient can be found to compensate the accuracy of the original motion.
2012, 31(3): 480-482,486.
Abstract:
The existing problems of manual electromagnet riveter such as overweight,high recoil shock and operating inconvenience were analyzed.For the purpose of solving the existing problems,a new damping system was presented in this paper based on the energy transition principle.Structural miniaturization design of the riveter was finished in connection with the new damping system.The riveter was divided into three parts: the driver,recoil system and riveter body based on the relative motion of the components at work and its prototype was manufactured.The test result indicated that the new electromagnet riveter was lower in recoil shock and more convenient to use without declining the efficiency in practical application.The miniaturization of electromagnet riveter was achieved.
The existing problems of manual electromagnet riveter such as overweight,high recoil shock and operating inconvenience were analyzed.For the purpose of solving the existing problems,a new damping system was presented in this paper based on the energy transition principle.Structural miniaturization design of the riveter was finished in connection with the new damping system.The riveter was divided into three parts: the driver,recoil system and riveter body based on the relative motion of the components at work and its prototype was manufactured.The test result indicated that the new electromagnet riveter was lower in recoil shock and more convenient to use without declining the efficiency in practical application.The miniaturization of electromagnet riveter was achieved.
2012, 31(3): 483-486.
Abstract:
An autoregressive model-based technique is proposed to detect flange screw-connected joints fault.The AR model can be validated by reference population which is defined as difference signal of normal conditions.The difference signal obtained in other preload conditions is defined as inspection population.The analyses of Euclide distance and Mahalanobis distance between reference population and inspection population indicate that autoregressive model-based geometrical distance is considered as effective index of screw-connected joints fault and it can be used to detect screw-connected joints fault.
An autoregressive model-based technique is proposed to detect flange screw-connected joints fault.The AR model can be validated by reference population which is defined as difference signal of normal conditions.The difference signal obtained in other preload conditions is defined as inspection population.The analyses of Euclide distance and Mahalanobis distance between reference population and inspection population indicate that autoregressive model-based geometrical distance is considered as effective index of screw-connected joints fault and it can be used to detect screw-connected joints fault.
2012, 31(3): 487-491,497.
Abstract:
In this paper,the force transfer path of structure(FTP) is taken as the design variables to obtain the load-carrying factor(LCF) by the integraion of internal force on the force transfer path.As the structure will change,so the LCF is the functional of structural FTP.Then differential equation of the shortest FTP is derived by variational method,and the equation is solved using the Ritz method to obtain the shortest PFT.Compared with the Michell truss theory and continuum structural topology optimization,the proposed method used two-step strategy: first the shortest FTP is obtained by variational method,and then the structural size optimization is conducted to get the minimum quality of the structure.Then a cantilever beam structure is takes the as an example to analyze the shortest FTP of structure under different shapes,and compared with the results obtained by the Michell theory,it proves the validity of the proposed model.In the present study,the optimal structure is obtained by the theoretical analysis without finite element modeling;therefore there is no numerical instability problem.On the other hand,as board-truss structure is used to simulate power transmission form,the current topology optimization research is generalized from a single unit structure to combination units.The present study also makes up the shortage of Michell criteria that it can only optimize the truss structure.
In this paper,the force transfer path of structure(FTP) is taken as the design variables to obtain the load-carrying factor(LCF) by the integraion of internal force on the force transfer path.As the structure will change,so the LCF is the functional of structural FTP.Then differential equation of the shortest FTP is derived by variational method,and the equation is solved using the Ritz method to obtain the shortest PFT.Compared with the Michell truss theory and continuum structural topology optimization,the proposed method used two-step strategy: first the shortest FTP is obtained by variational method,and then the structural size optimization is conducted to get the minimum quality of the structure.Then a cantilever beam structure is takes the as an example to analyze the shortest FTP of structure under different shapes,and compared with the results obtained by the Michell theory,it proves the validity of the proposed model.In the present study,the optimal structure is obtained by the theoretical analysis without finite element modeling;therefore there is no numerical instability problem.On the other hand,as board-truss structure is used to simulate power transmission form,the current topology optimization research is generalized from a single unit structure to combination units.The present study also makes up the shortage of Michell criteria that it can only optimize the truss structure.
2012, 31(3): 492-497.
Abstract:
Focusing on the conflicts among model size,calculation precision and computation speed in the complex vehicle structural modeling and simulation,the effects of vehicle exciting frequency and structural natural frequency cut-off on the structural dynamic response,were investigated in this paper based on the modal response linear cumulating method.Through introducing the concept of threshold value,the calculation method of modal cut-off frequency has been suggested,which is validated by an example of some armored vehicle rigid-flex coupled model.
Focusing on the conflicts among model size,calculation precision and computation speed in the complex vehicle structural modeling and simulation,the effects of vehicle exciting frequency and structural natural frequency cut-off on the structural dynamic response,were investigated in this paper based on the modal response linear cumulating method.Through introducing the concept of threshold value,the calculation method of modal cut-off frequency has been suggested,which is validated by an example of some armored vehicle rigid-flex coupled model.
2012, 31(3): 498-501,506.
Abstract:
In this paper,the transverse vibration equation of a pipe conveying fluid was deduced by the Hamilton's principle.The frequency equation was obtained by Galerkin Method,and expressions of the first four critical flow velocity,pressure and length of simple support were given out.Then,influences of flow velocity,pressure,length of simple support on natural frequencies and flow velocity,pressure on the critical flow velocity were analyzed.Finally,the sensitivity analysis of natural frequencies to flow velocity and pressure was analyzed.The results show: 1) Comparing with influence of length of simple support on natural frequencies,influences of flow velocity,pressure on natural frequencies are smaller;2) the first sensitivity of flow velocity to natural frequencies is higher than the first sensitivity of pressure to natural frequencies.
In this paper,the transverse vibration equation of a pipe conveying fluid was deduced by the Hamilton's principle.The frequency equation was obtained by Galerkin Method,and expressions of the first four critical flow velocity,pressure and length of simple support were given out.Then,influences of flow velocity,pressure,length of simple support on natural frequencies and flow velocity,pressure on the critical flow velocity were analyzed.Finally,the sensitivity analysis of natural frequencies to flow velocity and pressure was analyzed.The results show: 1) Comparing with influence of length of simple support on natural frequencies,influences of flow velocity,pressure on natural frequencies are smaller;2) the first sensitivity of flow velocity to natural frequencies is higher than the first sensitivity of pressure to natural frequencies.
2012, 31(3): 502-506.
Abstract:
Nanoindentation is an important method on measuring mechanical properties of materials at small scale.In this paper,the effectiveness of three representative indentation methods including olive-pharr method,Cheng-Cheng method and Ma method is studied.The accuracy and the effect of machine compliance calibration error are also investigated by means of the finite element analysis.It is concluded that Ma method is the best adaptability,the highest accuracy and the lowest sensitivity for machine compliance.The indentation results of aluminum and steel verifies the above-mentioned conclusions.
Nanoindentation is an important method on measuring mechanical properties of materials at small scale.In this paper,the effectiveness of three representative indentation methods including olive-pharr method,Cheng-Cheng method and Ma method is studied.The accuracy and the effect of machine compliance calibration error are also investigated by means of the finite element analysis.It is concluded that Ma method is the best adaptability,the highest accuracy and the lowest sensitivity for machine compliance.The indentation results of aluminum and steel verifies the above-mentioned conclusions.
2012, 31(3): 507-509,516.
Abstract:
Electromechanical integrated toroidal transmission is a new type of transmission mechanism that uses toroidal drive to integrate machinery,electromagnetism,permanent magnet and control.Based on the magnetic field theory,this paper computes the space distribution of the magnetic field of electromechanical integrated toroidal transmission planetary wheel with the integral method and the coordinate transformation method.It derives the formulas for computing the space distribution of the magnetic field and then does the computation.It also analyzes the factors that influence the space distribution of the magnetic field.
Electromechanical integrated toroidal transmission is a new type of transmission mechanism that uses toroidal drive to integrate machinery,electromagnetism,permanent magnet and control.Based on the magnetic field theory,this paper computes the space distribution of the magnetic field of electromechanical integrated toroidal transmission planetary wheel with the integral method and the coordinate transformation method.It derives the formulas for computing the space distribution of the magnetic field and then does the computation.It also analyzes the factors that influence the space distribution of the magnetic field.
2012, 31(3): 510-516.
Abstract:
In this paper,the six-degree of freedom(6-DOF) motion equations of elastic vibration isolation system were established and the natural frequency formulas have been derived under the elastic orthogonal and oblique supports.The kinetics model of 6-DOF vibration isolation system was built based on Matlab/SimMechanics and the modal simulation tests have been done in Simulink environment.The test results proved that the kinematical simulation tallies with the theoretical derivation.The kinematical model is realized in Matlab and lays the foundations of active control of 6-DOF vibration isolation.
In this paper,the six-degree of freedom(6-DOF) motion equations of elastic vibration isolation system were established and the natural frequency formulas have been derived under the elastic orthogonal and oblique supports.The kinetics model of 6-DOF vibration isolation system was built based on Matlab/SimMechanics and the modal simulation tests have been done in Simulink environment.The test results proved that the kinematical simulation tallies with the theoretical derivation.The kinematical model is realized in Matlab and lays the foundations of active control of 6-DOF vibration isolation.
