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RSS2013 Vol. 32, No. 3
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2013, 32(3): 313-318.
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Abstract:
The control strategies have essential influences on the dynamic stability of modern wind turbines. Thispaper presents a theoretical investigation on this topic. The investigation is motivated by a vibration measurement of4 wind turbines with capacity of 1. 5 MW in a wind park. The wind turbines always get into a violent axial vibrationabove rated wind speed,which is finally confirmed as an instability event associated with pitch control system. Inthis paper the mechanisms of control strategies influencing the dynamic stability are revealed,and the stability en-hancement by means of time delay in pitch control is ascertained. The results show that the optimum control of rota-tional speed for maximizing energy capture below rated power will improve the dynamic stability suppressing the axi-al unstable vibrations of wind turbines. Above rated wind speed,two control modes can be used to keep the poweroutput equal to rated power. One is fixed speed and variable pitch,and another is variable speed and variablepitch. However the control mode of fixed speed and variable pitch can cause unstable axial vibrations of wind tur-bines, pitch control with variable speed can suppress the unstable vibrations. Additionally an appropriate time delayτ in pitch control can effectively enhance the dynamic stability of wind turbines. The optimum time delay is Topt (Tis the period of the axial vibration of wind turbines).
The control strategies have essential influences on the dynamic stability of modern wind turbines. Thispaper presents a theoretical investigation on this topic. The investigation is motivated by a vibration measurement of4 wind turbines with capacity of 1. 5 MW in a wind park. The wind turbines always get into a violent axial vibrationabove rated wind speed,which is finally confirmed as an instability event associated with pitch control system. Inthis paper the mechanisms of control strategies influencing the dynamic stability are revealed,and the stability en-hancement by means of time delay in pitch control is ascertained. The results show that the optimum control of rota-tional speed for maximizing energy capture below rated power will improve the dynamic stability suppressing the axi-al unstable vibrations of wind turbines. Above rated wind speed,two control modes can be used to keep the poweroutput equal to rated power. One is fixed speed and variable pitch,and another is variable speed and variablepitch. However the control mode of fixed speed and variable pitch can cause unstable axial vibrations of wind tur-bines, pitch control with variable speed can suppress the unstable vibrations. Additionally an appropriate time delayτ in pitch control can effectively enhance the dynamic stability of wind turbines. The optimum time delay is Topt (Tis the period of the axial vibration of wind turbines).
2013, 32(3): 319-323.
Abstract:
Considering the internal dynamic excitation of a spiral bevel gearbox in the synchronization system of aship lift such as stiffness excitation,error excitation and meshing impact excitation,we established the dynamic fi-nite element model of the gearbox that includes meshing spiral bevel gears,transmission shafts,bearings and gear-box houses. The dynamic response of the gearbox is analyzed through using ANSYS, and consequently the displace-ment,speed and acceleration of the gearbox are obtained. Based on SYSNOISE,an acoustic boundary elementmodel of the gearbox is built by using the boundary conditions such as a node's vibration displacement from housingsurface. Then radiation noise prediction is carried out through the direct boundary element method,and the surfaceacoustic pressure contour on the housing surface and the radiation noise at determined field points is obtained. Theresults indicate that the peak values of dynamic response and radiation noise of the gearbox both appear at meshingfrequency and its octave frequencies.
Considering the internal dynamic excitation of a spiral bevel gearbox in the synchronization system of aship lift such as stiffness excitation,error excitation and meshing impact excitation,we established the dynamic fi-nite element model of the gearbox that includes meshing spiral bevel gears,transmission shafts,bearings and gear-box houses. The dynamic response of the gearbox is analyzed through using ANSYS, and consequently the displace-ment,speed and acceleration of the gearbox are obtained. Based on SYSNOISE,an acoustic boundary elementmodel of the gearbox is built by using the boundary conditions such as a node's vibration displacement from housingsurface. Then radiation noise prediction is carried out through the direct boundary element method,and the surfaceacoustic pressure contour on the housing surface and the radiation noise at determined field points is obtained. Theresults indicate that the peak values of dynamic response and radiation noise of the gearbox both appear at meshingfrequency and its octave frequencies.
2013, 32(3): 324-327.
Abstract:
If position tracking relies entirely on the response of the servo control system for target signals,then theacceleration may be too large and exceeds the system's response ability,the mechanical system is subject to vibra-tion and jitter,and the level of control difficulty is high. If the servo control system can calculate and trim themovement trajectories in real time according to the moving target,the servo control system will run more smoothly,the control difficulty is greatly reduced. The servo control system is divided into certain moving target and mobileuncertain target. We propose an algorithm that uses the five-order spline curve to plan the real time trajectory of thecertain moving target. The tracking speed,acceleration and jerk of the control system are continuous in the wholeprocess,which makes the tracking motion smooth. We also propose an algorithm that uses the S curve profile toplan the real time trajectory of the mobile uncertain target so as to achieve the real-time computing of the movingtarget trajectory. This makes the acceleration continuous when switch between multi-segments of the moving uncer-tain target and guarantees the tracking motion smoothness.
If position tracking relies entirely on the response of the servo control system for target signals,then theacceleration may be too large and exceeds the system's response ability,the mechanical system is subject to vibra-tion and jitter,and the level of control difficulty is high. If the servo control system can calculate and trim themovement trajectories in real time according to the moving target,the servo control system will run more smoothly,the control difficulty is greatly reduced. The servo control system is divided into certain moving target and mobileuncertain target. We propose an algorithm that uses the five-order spline curve to plan the real time trajectory of thecertain moving target. The tracking speed,acceleration and jerk of the control system are continuous in the wholeprocess,which makes the tracking motion smooth. We also propose an algorithm that uses the S curve profile toplan the real time trajectory of the mobile uncertain target so as to achieve the real-time computing of the movingtarget trajectory. This makes the acceleration continuous when switch between multi-segments of the moving uncer-tain target and guarantees the tracking motion smoothness.
2013, 32(3): 328-332.
Abstract:
The bearing chamber is an important component in aircraft engine. To understand the oil/air two phaseflow conditions in the bearing chamber is beneficial to improve the lubrication efficiency,working performance andreliability of an aircraft engine. The two phase flow conditions of the different flow patterns can be studied based onthe flow pattern recognition,which is a feasible way to obtain the physical phenomenon of two phase flows in thebearing chamber. Considering the experiment accessibility,recognition ability and the predecessors' works,the K-Means clustering analysis was employed to cluster the oil/air two phase flow pattern in the bearing chamber with thecharacteristic parameters on the wall surface nearby. The dimensionless two phase mixture velocity and the dimen-sionless pressure were chosen as the characteristic parameters for their remarkable difference in the flow pattern.The results of work indicate that the clustering approach is a successful one to identify the flow pattern in the bear-ing chamber. The work supports the physical conditions research, the lubrication design and the heat transfer analy-sis in the bearing chamber based on the flow pattern recognition.
The bearing chamber is an important component in aircraft engine. To understand the oil/air two phaseflow conditions in the bearing chamber is beneficial to improve the lubrication efficiency,working performance andreliability of an aircraft engine. The two phase flow conditions of the different flow patterns can be studied based onthe flow pattern recognition,which is a feasible way to obtain the physical phenomenon of two phase flows in thebearing chamber. Considering the experiment accessibility,recognition ability and the predecessors' works,the K-Means clustering analysis was employed to cluster the oil/air two phase flow pattern in the bearing chamber with thecharacteristic parameters on the wall surface nearby. The dimensionless two phase mixture velocity and the dimen-sionless pressure were chosen as the characteristic parameters for their remarkable difference in the flow pattern.The results of work indicate that the clustering approach is a successful one to identify the flow pattern in the bear-ing chamber. The work supports the physical conditions research, the lubrication design and the heat transfer analy-sis in the bearing chamber based on the flow pattern recognition.
2013, 32(3): 333-336.
Abstract:
In order to shorten the vehicle body design,the interpolation of 3D reconstruction method is widely usedin the vehicle body design. The familiar interpolation method is difficult to express the detail characterization of thereal surface well,and although the surface is smooth,it can't pass initial control points. A method that using of theDihedral angle bisection interpolation build new points on the initial triangles by Delaunay triangulation is proposedin the paper,the method approximate the original surface by interpolation,new surface of interpolation can pass in-itial control points. It suffice vehicle body contour modeling design. The experiments have proved that the methodhas high stability and preserves detail characterization. It is suited to popularize in surface reconstruction, and someother field.
In order to shorten the vehicle body design,the interpolation of 3D reconstruction method is widely usedin the vehicle body design. The familiar interpolation method is difficult to express the detail characterization of thereal surface well,and although the surface is smooth,it can't pass initial control points. A method that using of theDihedral angle bisection interpolation build new points on the initial triangles by Delaunay triangulation is proposedin the paper,the method approximate the original surface by interpolation,new surface of interpolation can pass in-itial control points. It suffice vehicle body contour modeling design. The experiments have proved that the methodhas high stability and preserves detail characterization. It is suited to popularize in surface reconstruction, and someother field.
2013, 32(3): 337-343.
Abstract:
To reflect fuzziness of information in product planning in an effective way,a multi-format information-based analysis approach of customer requirements was proposed. Firstly,decision-makers express their preferencesof the relative importance weights of customer requirements in their preferred formats; Secondly,some transforma-tion functions were used to unify the multi-format information into complementary judgment matrix,and priorities ofcomplementary judgment matrix were resolved by using normalizing rank aggregation method,then the initial impor-tance rating of customer requirements was determined by integrating with the weights of decision-makers; Finally,on the basis of combining the initial importance rating with the correction factor of each customer requirement,theimportance rating of customer requirements was acquired through normalization. An example of PE jaw crusher wasshown to illustrate the feasibility and validity of this approach.
To reflect fuzziness of information in product planning in an effective way,a multi-format information-based analysis approach of customer requirements was proposed. Firstly,decision-makers express their preferencesof the relative importance weights of customer requirements in their preferred formats; Secondly,some transforma-tion functions were used to unify the multi-format information into complementary judgment matrix,and priorities ofcomplementary judgment matrix were resolved by using normalizing rank aggregation method,then the initial impor-tance rating of customer requirements was determined by integrating with the weights of decision-makers; Finally,on the basis of combining the initial importance rating with the correction factor of each customer requirement,theimportance rating of customer requirements was acquired through normalization. An example of PE jaw crusher wasshown to illustrate the feasibility and validity of this approach.
2013, 32(3): 344-347.
Abstract:
Based on the binary interval number theory,a multiple indicator assessment model of fighter air combatcapability has been created,in which the weights are unknown. Evaluation indicators are the most important onesin modern air battles which include mobility,firepower parameters,air combat capability,detection parameters,manipulating coefficient and the voyage coefficient. Using the cosine formula to establish the optimization model ofmulti-attribute evaluation,the size of index segment of the cosine between the various models and the ideal modelare compared; then the air combat capability between flights can be described. The weight of subjectivity and thecalculation process can be reduced in this way. Finally,the model is used to a numerical example to verify the fea-sibility of the model.
Based on the binary interval number theory,a multiple indicator assessment model of fighter air combatcapability has been created,in which the weights are unknown. Evaluation indicators are the most important onesin modern air battles which include mobility,firepower parameters,air combat capability,detection parameters,manipulating coefficient and the voyage coefficient. Using the cosine formula to establish the optimization model ofmulti-attribute evaluation,the size of index segment of the cosine between the various models and the ideal modelare compared; then the air combat capability between flights can be described. The weight of subjectivity and thecalculation process can be reduced in this way. Finally,the model is used to a numerical example to verify the fea-sibility of the model.
2013, 32(3): 348-352.
Abstract:
On the basis of research on engagement principle of spur gear drive,a design method of tooth profilebased on line of action is presented. The mathematical models,including the equation of action line,the equationof the tooth profile for the driving gear,and the equation of the conjugate tooth profile,are established based on themeshing theory. The simulation result of the specific example demonstrates the design method is correct and feasi-ble. The contact ratio of the proposed gear drive is calculated. A comparison study of the contact ratio with the in-volute gear drive is also carried out in this work. It will be better to control the performances of a gear set by specif-ying the shape of action line rather than specifying tooth profiles of mating gear.
On the basis of research on engagement principle of spur gear drive,a design method of tooth profilebased on line of action is presented. The mathematical models,including the equation of action line,the equationof the tooth profile for the driving gear,and the equation of the conjugate tooth profile,are established based on themeshing theory. The simulation result of the specific example demonstrates the design method is correct and feasi-ble. The contact ratio of the proposed gear drive is calculated. A comparison study of the contact ratio with the in-volute gear drive is also carried out in this work. It will be better to control the performances of a gear set by specif-ying the shape of action line rather than specifying tooth profiles of mating gear.
2013, 32(3): 353-357.
Abstract:
A typical airplane fuselage from FS380 to FS500 is utilized to study the influences of different impact condi-tions on fuselage crashworthiness. The finite element model of the fuselage structure is established and the crashworthi-ness characteristics are simulated when v =9.133 m/s under the condition of 0 roll angle, 10�left roll angle,and withhorizontal acceleration separately. The overall deformation and the acceleration history curves at seats are compared. Theresults show that the left roll angle changes the fuselage deformation and the acceleration at seats obviously,while thedeformation of the floors increases and the acceleration at the seats decreases when the horizontal acceleration is consid-ered. A suitable emergence landing conditions can increase the aircraft crashworthiness.
A typical airplane fuselage from FS380 to FS500 is utilized to study the influences of different impact condi-tions on fuselage crashworthiness. The finite element model of the fuselage structure is established and the crashworthi-ness characteristics are simulated when v =9.133 m/s under the condition of 0 roll angle, 10�left roll angle,and withhorizontal acceleration separately. The overall deformation and the acceleration history curves at seats are compared. Theresults show that the left roll angle changes the fuselage deformation and the acceleration at seats obviously,while thedeformation of the floors increases and the acceleration at the seats decreases when the horizontal acceleration is consid-ered. A suitable emergence landing conditions can increase the aircraft crashworthiness.
2013, 32(3): 358-361.
Abstract:
The FEA model of a large-scale canned motor pump rotor is established based on ANSYS. The effects ofgyroscopic effect on the critical rotating speed and the mass unbalance response are investigated by using modalanalysis and harmonic response analysis. The analytical results show that the gyroscopic effect obviously affects crit-ical rotating speed and should be considered in the rotordynamic analysis. The calculated critical rotating speed ishigher than the design value when the gyroscopic effect is considered. The first resonant peak values of mass unbal-ance response in all test points are within the design vibration limit. The vibration amplitudes of the impeller, upperand lower flywheel centres far exceed other test points. These test points are susceptive to vibration and should bemonitored carefully in operation.
The FEA model of a large-scale canned motor pump rotor is established based on ANSYS. The effects ofgyroscopic effect on the critical rotating speed and the mass unbalance response are investigated by using modalanalysis and harmonic response analysis. The analytical results show that the gyroscopic effect obviously affects crit-ical rotating speed and should be considered in the rotordynamic analysis. The calculated critical rotating speed ishigher than the design value when the gyroscopic effect is considered. The first resonant peak values of mass unbal-ance response in all test points are within the design vibration limit. The vibration amplitudes of the impeller, upperand lower flywheel centres far exceed other test points. These test points are susceptive to vibration and should bemonitored carefully in operation.
2013, 32(3): 362-366.
Abstract:
The vacuum cleaning vehicle is a new kind of sweeper which uses negative pressure. Its dust suctionmouth,as a key component of its gas path system,plays an important role in dust-sucking capability,cleaning effi-ciency,reliability and other aspects of the sweeping vehicle. Taking the dust suction mouth as research object,athree-dimensional model of the dust suction mouth was built with UG software. Grid was generated with Gambit soft-ware,and flow field was analyzed with Fluent software. Theeffects of different structures of the dust suction mouthwith curled edges on the dust suction were compared; a dust suction mouth with front curved plate was designed,and simulation of the gas-solid flow motion was completed. The simulation results show that the dust suction mouthwith wide front edge or narrow rear edge or curved front plate has excellent dust suction effects.
The vacuum cleaning vehicle is a new kind of sweeper which uses negative pressure. Its dust suctionmouth,as a key component of its gas path system,plays an important role in dust-sucking capability,cleaning effi-ciency,reliability and other aspects of the sweeping vehicle. Taking the dust suction mouth as research object,athree-dimensional model of the dust suction mouth was built with UG software. Grid was generated with Gambit soft-ware,and flow field was analyzed with Fluent software. Theeffects of different structures of the dust suction mouthwith curled edges on the dust suction were compared; a dust suction mouth with front curved plate was designed,and simulation of the gas-solid flow motion was completed. The simulation results show that the dust suction mouthwith wide front edge or narrow rear edge or curved front plate has excellent dust suction effects.
2013, 32(3): 367-371.
Abstract:
Priority analysis of system failure mode has important significance in reliability design and reliability allo-cation of system. Motorized spindle is one of the most important parts of modern high speed precision machine tool,and its high reliability and longer life spans have been required. The priority analysis of failure modes for the motor-ized spindle has been made by Decision Making Trial and Evaluation Laboratory (DEMATEL) technique,withfully considering the links between the failure modes and effects of the motorized spindle system. And the sugges-tion of failure mode priority to improve reliability of motorized spindle system has been proposed comparing with theconclusion of conventional Risk Priority Number (RPN) method.
Priority analysis of system failure mode has important significance in reliability design and reliability allo-cation of system. Motorized spindle is one of the most important parts of modern high speed precision machine tool,and its high reliability and longer life spans have been required. The priority analysis of failure modes for the motor-ized spindle has been made by Decision Making Trial and Evaluation Laboratory (DEMATEL) technique,withfully considering the links between the failure modes and effects of the motorized spindle system. And the sugges-tion of failure mode priority to improve reliability of motorized spindle system has been proposed comparing with theconclusion of conventional Risk Priority Number (RPN) method.
2013, 32(3): 372-376.
Abstract:
A hybrid algorithm based on Tabu Search (TS) and Mathematical Programming (MP) for Just-in-timeJob-shop Scheduling Problem (JIT-JSP) is introduced in this paper,in which each operation has an earliness and atardiness cost with respect to its due date and the objective is to find a feasible scheduling minimizing the total earli-ness and tardiness costs. During search process,any individual offers the sequence orders in which the operationsshould be scheduled to the machines,and then MP method optimizes the completion times of the operations for thegenerated sequences. In order to reduce computational time,we introduce an excellent neighborhood structurebased on swap and insertion operator. The experimental results finally demonstrate the effectiveness of the proposedhybrid algorithm over a wide range of benchmarks.
A hybrid algorithm based on Tabu Search (TS) and Mathematical Programming (MP) for Just-in-timeJob-shop Scheduling Problem (JIT-JSP) is introduced in this paper,in which each operation has an earliness and atardiness cost with respect to its due date and the objective is to find a feasible scheduling minimizing the total earli-ness and tardiness costs. During search process,any individual offers the sequence orders in which the operationsshould be scheduled to the machines,and then MP method optimizes the completion times of the operations for thegenerated sequences. In order to reduce computational time,we introduce an excellent neighborhood structurebased on swap and insertion operator. The experimental results finally demonstrate the effectiveness of the proposedhybrid algorithm over a wide range of benchmarks.
2013, 32(3): 377-382.
Abstract:
Unsteady computation of 3-D flow field in centrifugal pump is calculated,and static pressure distributionof centrifugal pump is analyzed. The volute and the hydrodynamic radial direction forces on the impeller are investi-gated,and the effect on vibration characteristics and the shaft centerline orbit of centrifugal bump system are ob-tained and analyzed. The calculated result shows that the flow field of centrifugal pump is reasonable,the calculat-ed steady force is close to experimental result,the unsteady forces are related to impeller-tongue interactions; Un-der the action of hydrodynamic forces,the frequencies of hydrodynamic forces and harmonics occur in rotor of thecentrifugal pump.
Unsteady computation of 3-D flow field in centrifugal pump is calculated,and static pressure distributionof centrifugal pump is analyzed. The volute and the hydrodynamic radial direction forces on the impeller are investi-gated,and the effect on vibration characteristics and the shaft centerline orbit of centrifugal bump system are ob-tained and analyzed. The calculated result shows that the flow field of centrifugal pump is reasonable,the calculat-ed steady force is close to experimental result,the unsteady forces are related to impeller-tongue interactions; Un-der the action of hydrodynamic forces,the frequencies of hydrodynamic forces and harmonics occur in rotor of thecentrifugal pump.
2013, 32(3): 383-387.
Abstract:
Based on the cost-benefit analysis,with the evaluation index of annual cost and initial cost,the designand analysis model for powertrain for plug-in hybrid electric vehicle (PHEV) had been established and the parame-ter of PHEV's powertrain had been studied. When the PHEV's all-electric range (AER) is equal to the daily dis-tance,the best average annual cost and the largest reduction in petroleum consumption are achieved. And obtainthe importance of the personal transportation survey for PHEV. Energy storage system (ESS) capacity, the depth ofdischarge and power of ESS can designed based on PHEV's service life,cost,mass and size,and obtain thePHEV's powertrain cost based on power/energy ratio (RP/E) analysis.
Based on the cost-benefit analysis,with the evaluation index of annual cost and initial cost,the designand analysis model for powertrain for plug-in hybrid electric vehicle (PHEV) had been established and the parame-ter of PHEV's powertrain had been studied. When the PHEV's all-electric range (AER) is equal to the daily dis-tance,the best average annual cost and the largest reduction in petroleum consumption are achieved. And obtainthe importance of the personal transportation survey for PHEV. Energy storage system (ESS) capacity, the depth ofdischarge and power of ESS can designed based on PHEV's service life,cost,mass and size,and obtain thePHEV's powertrain cost based on power/energy ratio (RP/E) analysis.
2013, 32(3): 388-394.
Abstract:
In this paper ,the method of liquid-solid two-phase flow is used to simulate with the multiple referenceframe (MRF),the Eulerian multiphase flow model,the RNG k-ε turbulence model in the fluent software , and thecharacteristics of flow field and stirring power of double-layer impellers is analyzed under different conditions in thevertical stirred tank. The results show that different combined impellers have affected the macroscopic flow charac-teristics significantly. When the upper and lower impellers are different,the turbulent kinetic energy of the mixtureis enhanced,circular flow is increased,and the mixing effect is improved,so we choose the double-layer upper-in-clined lower-vertical impeller as the optimal impeller. On analyzing the stirred shaft power,it is concluded that thelarger rotational speed has a larger stirring power, and with particle size increasing, the stirred power increases aftera decrease,and particle volume fraction has a light effect to the stirred power,and the maximum error between thesimulation and experimental results is 15%.
In this paper ,the method of liquid-solid two-phase flow is used to simulate with the multiple referenceframe (MRF),the Eulerian multiphase flow model,the RNG k-ε turbulence model in the fluent software , and thecharacteristics of flow field and stirring power of double-layer impellers is analyzed under different conditions in thevertical stirred tank. The results show that different combined impellers have affected the macroscopic flow charac-teristics significantly. When the upper and lower impellers are different,the turbulent kinetic energy of the mixtureis enhanced,circular flow is increased,and the mixing effect is improved,so we choose the double-layer upper-in-clined lower-vertical impeller as the optimal impeller. On analyzing the stirred shaft power,it is concluded that thelarger rotational speed has a larger stirring power, and with particle size increasing, the stirred power increases aftera decrease,and particle volume fraction has a light effect to the stirred power,and the maximum error between thesimulation and experimental results is 15%.
2013, 32(3): 395-398.
Abstract:
Information about the stability of vibration motions is essential for ensuring the safety designs of a rotor-bearing system and the safe operation. This paper established a new model of a flexible rotor across its critical speedand with transient dynamic deflection,acceleration and damping coefficient change. The critical speed dynamic de-flection curve is obtained with the Newmark-β integral method. The paper simulates the differential equation of crit-ical speed; the simulation results show that the integral method is effective for a flexible rotor to pass its criticalspeed smoothly.
Information about the stability of vibration motions is essential for ensuring the safety designs of a rotor-bearing system and the safe operation. This paper established a new model of a flexible rotor across its critical speedand with transient dynamic deflection,acceleration and damping coefficient change. The critical speed dynamic de-flection curve is obtained with the Newmark-β integral method. The paper simulates the differential equation of crit-ical speed; the simulation results show that the integral method is effective for a flexible rotor to pass its criticalspeed smoothly.
2013, 32(3): 399-404.
Abstract:
In this paper,we present a new printing image registration error detection method based on the DECM(Distant Edge Co-occurrence Matrix). We use printing image information to register errors. Firstly,we collect aprinting image with the CCD camera and convert it from RGB color space to CMYK color space. Secondly,we sep-arate the image into C, M, Y, K color channels and obtain the edge image of each channel. We calculate the trans-lation distance between detecting the edge images (C,M,Y) and the reference edge image (K). The method pro-posed in this paper can easily compute the four-color overprint deviation. The simulation results and experimentalresults have good agreement,indicating that the method is correct and effective.
In this paper,we present a new printing image registration error detection method based on the DECM(Distant Edge Co-occurrence Matrix). We use printing image information to register errors. Firstly,we collect aprinting image with the CCD camera and convert it from RGB color space to CMYK color space. Secondly,we sep-arate the image into C, M, Y, K color channels and obtain the edge image of each channel. We calculate the trans-lation distance between detecting the edge images (C,M,Y) and the reference edge image (K). The method pro-posed in this paper can easily compute the four-color overprint deviation. The simulation results and experimentalresults have good agreement,indicating that the method is correct and effective.
2013, 32(3): 405-409.
Abstract:
The three-dimensional thermo-elastic coupling finite element model (FEM) of a double-leading-shoebrake was established by equaling radiation heat transfer to convective heat transfer. The transient temperaturefield,stress field and deformation field of the brake were numerically simulated several times under the continuousbraking condition and by considering the braking friction torque. The transient temperature,heat stress and thermo-elastic coupling strength change on the internal and external surfaces of the brake were obtained.
The three-dimensional thermo-elastic coupling finite element model (FEM) of a double-leading-shoebrake was established by equaling radiation heat transfer to convective heat transfer. The transient temperaturefield,stress field and deformation field of the brake were numerically simulated several times under the continuousbraking condition and by considering the braking friction torque. The transient temperature,heat stress and thermo-elastic coupling strength change on the internal and external surfaces of the brake were obtained.
2013, 32(3): 410-415.
Abstract:
The use of the wet dual clutch automatic transmission can help a vehicle meet the requirements for itssmooth and fast start. The paper introduces the structure and working principles of the dual clutch automatic trans-mission. The automatic transmission start model is built by using the Matlab/Simulink module; it can start the twoclutches simultaneously. According to different conditions,the clutch start control strategy controls two hydraulicparameters to ensure that the vehicle starts fast and smoothly. The start of the dual clutch automatic transmission issimulated; the simulation results show that the acceleration,impact degree and clutch slipping power are suitablefor starting a vehicle.
The use of the wet dual clutch automatic transmission can help a vehicle meet the requirements for itssmooth and fast start. The paper introduces the structure and working principles of the dual clutch automatic trans-mission. The automatic transmission start model is built by using the Matlab/Simulink module; it can start the twoclutches simultaneously. According to different conditions,the clutch start control strategy controls two hydraulicparameters to ensure that the vehicle starts fast and smoothly. The start of the dual clutch automatic transmission issimulated; the simulation results show that the acceleration,impact degree and clutch slipping power are suitablefor starting a vehicle.
2013, 32(3): 416-420.
Abstract:
Based on the first passage failure principle,the dynamic reliability model of diamondback wing underthe random wind load was established,and then its dynamic reliability sensitivity was analyzed under the same con-dition. Via researching the times with structural dynamic response passing through the safety limit on the load ofrandom vibration, the dynamic reliability model of diamondback wing was obtained. And its dynamic reliability sen-sitivity under wind load was investigated by using the comprehensive analysis technology. The results show that,inconsidering the random wind load only,to increase wing thickness and chord length of back wing or reduce chordlength of front wing and leading edge sweepback can improve the dynamic reliability of diamondback wing underwind load. But it is needed to take synthetically into account the aerodynamic contour and other loads in engineer-ing design.
Based on the first passage failure principle,the dynamic reliability model of diamondback wing underthe random wind load was established,and then its dynamic reliability sensitivity was analyzed under the same con-dition. Via researching the times with structural dynamic response passing through the safety limit on the load ofrandom vibration, the dynamic reliability model of diamondback wing was obtained. And its dynamic reliability sen-sitivity under wind load was investigated by using the comprehensive analysis technology. The results show that,inconsidering the random wind load only,to increase wing thickness and chord length of back wing or reduce chordlength of front wing and leading edge sweepback can improve the dynamic reliability of diamondback wing underwind load. But it is needed to take synthetically into account the aerodynamic contour and other loads in engineer-ing design.
2013, 32(3): 421-425.
Abstract:
An improved algebraic solution is developed to deal with the 4-degree of freedom manipulator USSTROBORTwhich has two coupled axes and two parallel axes. In the basis of considering manipulator constraints,the kinematicalmodel is built in the basis of joint variables by the method of Denavit-Hartenberg,than the forward kinematics and in-verse kinematics solution is obtained by the variables separation method in the way of matrix inverse multiplier. Trajecto-ry planning is based on the cubic polynomial method, using the Matlab Robotics Tool to simulate the robotic arm, whichvalidates that the kinematical model is correct. The curves of angle vs. time and velocity vs. time, acceleration vs. timeof each joint are obtained. The actual movement validates the simulation result and kinematical solution. The kinematicalmodel provides a basis for the design of the controller of USSTROBOT.
An improved algebraic solution is developed to deal with the 4-degree of freedom manipulator USSTROBORTwhich has two coupled axes and two parallel axes. In the basis of considering manipulator constraints,the kinematicalmodel is built in the basis of joint variables by the method of Denavit-Hartenberg,than the forward kinematics and in-verse kinematics solution is obtained by the variables separation method in the way of matrix inverse multiplier. Trajecto-ry planning is based on the cubic polynomial method, using the Matlab Robotics Tool to simulate the robotic arm, whichvalidates that the kinematical model is correct. The curves of angle vs. time and velocity vs. time, acceleration vs. timeof each joint are obtained. The actual movement validates the simulation result and kinematical solution. The kinematicalmodel provides a basis for the design of the controller of USSTROBOT.
2013, 32(3): 426-429.
Abstract:
The variation rules of the velocity,load and dynamic response in the spread process of rudder for an un-derwater vehicle were studied by using computational fluid dynamics method and dynamic mesh techniques, and thefactors affecting the spread of rudder such as high temperature combustible gas in the tail of rudder and underwatervehicle motion speed were also analyzed. The proof testing schemes were designed based on the speed equivalentprinciple and the displacement-time curves and stress-time curves and the relation between the rudder spread timeand the exiting water speed in the spread process of rudder were obtained in the tests. It was concluded that the cal-culation results can provide dependence for the analysis on trajectories of underwater vehicle and rudder structuredesign and material option.
The variation rules of the velocity,load and dynamic response in the spread process of rudder for an un-derwater vehicle were studied by using computational fluid dynamics method and dynamic mesh techniques, and thefactors affecting the spread of rudder such as high temperature combustible gas in the tail of rudder and underwatervehicle motion speed were also analyzed. The proof testing schemes were designed based on the speed equivalentprinciple and the displacement-time curves and stress-time curves and the relation between the rudder spread timeand the exiting water speed in the spread process of rudder were obtained in the tests. It was concluded that the cal-culation results can provide dependence for the analysis on trajectories of underwater vehicle and rudder structuredesign and material option.
2013, 32(3): 430-434.
Abstract:
Parameter transfer is very important in assembly variant design,and building equation is an effectivemethod in realizing parameter transfer. By analyzing characteristics of assembly constraints,expression of assemblysemantics and definition of assembly constraint relation are illustrated. Assembly constraints library base on assem-bly semantics and constraint relations is constructed,of which structure,function and contents are briefly de-scribed. Based on the expression of assembly semantics and definition of assembly constraint relation,the similarityalgorithm of constraint relations is analyzed and studied,the formula of similarity suitable to assembly constraints li-brary is deduced. And automatic generation of dimension constraint is realized in a certain degree. The method isverified and realized by a concrete example.
Parameter transfer is very important in assembly variant design,and building equation is an effectivemethod in realizing parameter transfer. By analyzing characteristics of assembly constraints,expression of assemblysemantics and definition of assembly constraint relation are illustrated. Assembly constraints library base on assem-bly semantics and constraint relations is constructed,of which structure,function and contents are briefly de-scribed. Based on the expression of assembly semantics and definition of assembly constraint relation,the similarityalgorithm of constraint relations is analyzed and studied,the formula of similarity suitable to assembly constraints li-brary is deduced. And automatic generation of dimension constraint is realized in a certain degree. The method isverified and realized by a concrete example.
2013, 32(3): 435-440.
Abstract:
The undulating motion of a biomimetic fish fin can be classified into two modes: 1) the amplitude keepsconstant; 2) the amplitude changes gradually with its position. The study of the two modes can provide useful infor-mation for controlling an artificial fish fin. We build a two-dimensional mathematical model of the undulating motionmodes with the computational fluid dynamics (CFD) technology. With the mathematical model,we compare thepressure contour and average generative force of the two motion modes with the same Re number and kinematical pa-rameters (frequency,wave velocity and average amplitude) and discuss the change in drag coefficient with time.The simulation results show that the undulating motion mode with the constant amplitude of the fish fin generates alarger propulsion force and a higher propulsion stability. Finally,we explain the reasons for the difference betweenpropulsion results of the two modes with the vortex distribution and intensity in the wake.
The undulating motion of a biomimetic fish fin can be classified into two modes: 1) the amplitude keepsconstant; 2) the amplitude changes gradually with its position. The study of the two modes can provide useful infor-mation for controlling an artificial fish fin. We build a two-dimensional mathematical model of the undulating motionmodes with the computational fluid dynamics (CFD) technology. With the mathematical model,we compare thepressure contour and average generative force of the two motion modes with the same Re number and kinematical pa-rameters (frequency,wave velocity and average amplitude) and discuss the change in drag coefficient with time.The simulation results show that the undulating motion mode with the constant amplitude of the fish fin generates alarger propulsion force and a higher propulsion stability. Finally,we explain the reasons for the difference betweenpropulsion results of the two modes with the vortex distribution and intensity in the wake.
2013, 32(3): 441-447.
Abstract:
In order to obtain simulation results,the assumptive process file of part and scheduling files of machinetool tasks were adopted as original data of simulation procedures. The simulation results were recorded. The pro-duction logistics data from running process were analyzed and the running state of single equipment and the interac-tion of multiple sets of were analyzed with the simulation results. The validity of production logistics system modelsof FMS(flexible manufacturing system) and the simulation procedures as well as the effectiveness of planning andsetup of FMS logistics system were verified.
In order to obtain simulation results,the assumptive process file of part and scheduling files of machinetool tasks were adopted as original data of simulation procedures. The simulation results were recorded. The pro-duction logistics data from running process were analyzed and the running state of single equipment and the interac-tion of multiple sets of were analyzed with the simulation results. The validity of production logistics system modelsof FMS(flexible manufacturing system) and the simulation procedures as well as the effectiveness of planning andsetup of FMS logistics system were verified.
2013, 32(3): 448-451,456.
Abstract:
A novel solution for 2D irregular parts nesting with immune genetic algorithm(IGA) was presented,which overcome the shortages of premature constringency and low efficiency existing in genetic algorithms(GA).The immune memory and concentration mechanism of artificial immune system was introduced in global randomsearching of IGA. Vaccination realized individual gene a local adjustment and optimization,and the best individualcould be saved in immune memory library to improve the search speed of algorithm. At the same time the concen-tration mechanism ensured genetic population diversity during crossover and mutation process, expanded the search-ing space,more conducive to the optimal solution of the acquisition. Comparing with the standard genetic algo-rithm,the experimental results by immune genetic algorithm showed that the utilization of material is increased,theeffectiveness has been fairly proved in solving irregular parts nesting problem.
A novel solution for 2D irregular parts nesting with immune genetic algorithm(IGA) was presented,which overcome the shortages of premature constringency and low efficiency existing in genetic algorithms(GA).The immune memory and concentration mechanism of artificial immune system was introduced in global randomsearching of IGA. Vaccination realized individual gene a local adjustment and optimization,and the best individualcould be saved in immune memory library to improve the search speed of algorithm. At the same time the concen-tration mechanism ensured genetic population diversity during crossover and mutation process, expanded the search-ing space,more conducive to the optimal solution of the acquisition. Comparing with the standard genetic algo-rithm,the experimental results by immune genetic algorithm showed that the utilization of material is increased,theeffectiveness has been fairly proved in solving irregular parts nesting problem.
2013, 32(3): 452-456.
Abstract:
Based on the parameters of standard gear contact test bench, a non-standard gear specimen was designed inthis paper. Considering the gear meshing,processing and gluing,a multiple objective function optimization model wasestablished, which aimed to the minimum energy consumption, the shortest fatigue life of test gear and the longest fatiguelife of accompany trial gear. In order to improve the accuracy of computation and operation efficiency,Non-dominatedSorting Genetic Algorithm-Ⅱwas used and the elitist strategy was introduced. Considering the non-standard factor influ-ence on carrying capacity of gear,gear specimen design procedure was discussed and developed. Taking the two testbenches of different center distances in Jinan Shijin group and Newcastle University for examples, the design procedurescorrectness was verified, in which the non-standard gear can be researched on standard testing machine. It was conclu-ded that using standard gear contact test machine to study non-standard gear contact fatigue life is effective.
Based on the parameters of standard gear contact test bench, a non-standard gear specimen was designed inthis paper. Considering the gear meshing,processing and gluing,a multiple objective function optimization model wasestablished, which aimed to the minimum energy consumption, the shortest fatigue life of test gear and the longest fatiguelife of accompany trial gear. In order to improve the accuracy of computation and operation efficiency,Non-dominatedSorting Genetic Algorithm-Ⅱwas used and the elitist strategy was introduced. Considering the non-standard factor influ-ence on carrying capacity of gear,gear specimen design procedure was discussed and developed. Taking the two testbenches of different center distances in Jinan Shijin group and Newcastle University for examples, the design procedurescorrectness was verified, in which the non-standard gear can be researched on standard testing machine. It was conclu-ded that using standard gear contact test machine to study non-standard gear contact fatigue life is effective.
2013, 32(3): 457-461,468.
Abstract:
A new wireless network indoor positioning system was developed based on nRF24L01. The system used ultra-sonic positioned method and was composed of a computer, a main controller and many wireless network nodes. The maincontroller and the wireless network node adopted STC12C5616AD as the core control unit. The main controller transiteddata to host computer for processing through the SCI ports,and then feedback the processed data to position system tocontrol the mobile robot(MR). The system achieved wireless communication among the indoor positioning system,themobile robot and the host computer. Experimental results show that this control method has the advantages of low cost,simple structure, reliable wireless data transmission, strong anti-interference ability and high positioning accuracy.
A new wireless network indoor positioning system was developed based on nRF24L01. The system used ultra-sonic positioned method and was composed of a computer, a main controller and many wireless network nodes. The maincontroller and the wireless network node adopted STC12C5616AD as the core control unit. The main controller transiteddata to host computer for processing through the SCI ports,and then feedback the processed data to position system tocontrol the mobile robot(MR). The system achieved wireless communication among the indoor positioning system,themobile robot and the host computer. Experimental results show that this control method has the advantages of low cost,simple structure, reliable wireless data transmission, strong anti-interference ability and high positioning accuracy.
2013, 32(3): 462-468.
Abstract:
In order to study the complex stress and strain field of composite under biaxial load,a new modified AntColony Optimization (ACO) is proposed in this paper for shape and size optimization of composite cruciform speci-men. Due to the strong dependence of global best value in the iterations and special requirements of specimen de-sign,the ant's move method and pheromone updating strategy were modified,and a classical example was also em-ployed to demonstrate validation and versatility of the modified algorithm. A FEM parametric modeling techniquewas coupled with the modified ACO so as to optimize the geometry of composite cruciform specimen. The optimiza-tion result shows that a uniform strain field is obtained in the test zone and the convergence process of the optimiza-tion is quick.
In order to study the complex stress and strain field of composite under biaxial load,a new modified AntColony Optimization (ACO) is proposed in this paper for shape and size optimization of composite cruciform speci-men. Due to the strong dependence of global best value in the iterations and special requirements of specimen de-sign,the ant's move method and pheromone updating strategy were modified,and a classical example was also em-ployed to demonstrate validation and versatility of the modified algorithm. A FEM parametric modeling techniquewas coupled with the modified ACO so as to optimize the geometry of composite cruciform specimen. The optimiza-tion result shows that a uniform strain field is obtained in the test zone and the convergence process of the optimiza-tion is quick.
