Transactions of Nanjing University of Aeronautics & Astronautics
Volume 34,Issue 1,2017 Table of Contents
2017, 34(1):1-8.
DOI: 10.16356/j.1005-1120.2017.01.001
Abstract:
To satisfy the demand on dynamic performance and load characteristics of piezoelectric actuators in aeronautics and astronautics fields, a novel 2D piezo-nanopositioning stage utilizing a triangle amplifier mechanism is proposed. The stage is driven by piezoelectric rhombic units in both X and Y directions, which is composed of four piezoelectric stacks. Theoretical static model develops the relationships among output force, displacement, static stiffness and the structure parameters of the platform. The experimental results of the prototype show that the output performances in X and Y directions are similar and both of them are within an 8% deviation from the theoretical values. The stroke of the stage reaches 41.6 μm and 42.9 μm in X and Y directions, respectively, and is directly proportional to the amplitude of the input sinusoidal voltage 10 Hz. Moreover, the nano-positioning stage is featured with bidirectional symmetrical output characteristic and millisecond starting characteristic, whose minimum output displacement step is 50 nm.
To satisfy the demand on dynamic performance and load characteristics of piezoelectric actuators in aeronautics and astronautics fields, a novel 2D piezo-nanopositioning stage utilizing a triangle amplifier mechanism is proposed. The stage is driven by piezoelectric rhombic units in both X and Y directions, which is composed of four piezoelectric stacks. Theoretical static model develops the relationships among output force, displacement, static stiffness and the structure parameters of the platform. The experimental results of the prototype show that the output performances in X and Y directions are similar and both of them are within an 8% deviation from the theoretical values. The stroke of the stage reaches 41.6 μm and 42.9 μm in X and Y directions, respectively, and is directly proportional to the amplitude of the input sinusoidal voltage 10 Hz. Moreover, the nano-positioning stage is featured with bidirectional symmetrical output characteristic and millisecond starting characteristic, whose minimum output displacement step is 50 nm.
2017, 34(1):9-14.
DOI: 10.16356/j.1005-1120.2017.01.009
Abstract:
An electroaeroelastic model for wind energy harvesting using piezoelectric generators is presented. The flow field is mapped in detail. The force which the fluid flow exerts on the generator is formulated. The output voltage levels generated from the mechanical strain within the piezoelectric elements are determined. An analytical model is developed with consideration of the interactions between the fluid, solid and electric. Various analytical results are obtained, such as flow velocity contour and pressure contour for the flow, moving trajectories, stress contour and output voltage of the harvester. A prototype is fabricated and tested. The simulation result is close to the experimental result. The model developed in this paper can predict the performance and behavior of different energy harvesters. And it also can be used as a design tool for optimizing the performance of the harvester.
An electroaeroelastic model for wind energy harvesting using piezoelectric generators is presented. The flow field is mapped in detail. The force which the fluid flow exerts on the generator is formulated. The output voltage levels generated from the mechanical strain within the piezoelectric elements are determined. An analytical model is developed with consideration of the interactions between the fluid, solid and electric. Various analytical results are obtained, such as flow velocity contour and pressure contour for the flow, moving trajectories, stress contour and output voltage of the harvester. A prototype is fabricated and tested. The simulation result is close to the experimental result. The model developed in this paper can predict the performance and behavior of different energy harvesters. And it also can be used as a design tool for optimizing the performance of the harvester.
2017, 34(1):15-21.
DOI: 10.16356/j.1005-1120.2017.01.015
Abstract:
Attitude control system is one of the most important subsystems in a spacecraft. As a key actuator, the control moment gyroscope (CMG) mainly determines the performance of attitude control system. Whereas, the control accuracy and output torque smoothness of the CMG depends more on its gimbal servo system. Considering the constraints of size, mass and power consumption for a small satellite, here, a mini-CMG is designed, in which the gimbal servo system is driven by an ultrasonic motor. The good performances of the CMG are obtained by both the ultrasonic motor and the rotary inductosyn. The direct drive of gimbal improves its dynamic performance, with the output bandwidth above 20 Hz. The angular and speed closed-loop control obtains the 0.02 °/s gimbal rate, and the output torque resolution better than 2×10-3 N·m. The ultrasonic motor provides 1.0 N·m self-lock torque during power-off, with 12 arc-second position accuracy.
Attitude control system is one of the most important subsystems in a spacecraft. As a key actuator, the control moment gyroscope (CMG) mainly determines the performance of attitude control system. Whereas, the control accuracy and output torque smoothness of the CMG depends more on its gimbal servo system. Considering the constraints of size, mass and power consumption for a small satellite, here, a mini-CMG is designed, in which the gimbal servo system is driven by an ultrasonic motor. The good performances of the CMG are obtained by both the ultrasonic motor and the rotary inductosyn. The direct drive of gimbal improves its dynamic performance, with the output bandwidth above 20 Hz. The angular and speed closed-loop control obtains the 0.02 °/s gimbal rate, and the output torque resolution better than 2×10-3 N·m. The ultrasonic motor provides 1.0 N·m self-lock torque during power-off, with 12 arc-second position accuracy.
2017, 34(1):22-29.
DOI: 10.16356/j.1005-1120.2017.01.022
Abstract:
To investigate a novel macro and micro driven linear piezoelectric motor composed of an ultrasonic motor with macro movement and a piezoelectric actuator with micro movement, a digital signal processing (DSP) based macro and micro power supply is designed, which fits the new linear piezoelectric motor. The power supply comprises a control circuit, a voltage conversion circuit, an amplifier circuit, a half-bridge module, an optical isolators-drive circuit, etc, where the DSP of TMS320F28335 is used as the controller. When the linear piezoelectric motor working in a macro driven state, the power supply outputs alternating currents with high frequency and high voltage, which drives the linear piezoelectric motor dynamically at an ultrasonic frequency; while working in the micro driven state, the power supply outputs direct currents with high voltage, which drives the linear piezoelectric motor in micro driven statically. Here a prototype of the macro-micro power supply is designed. After a series of experiments on the power supply with and without loads, the results show that the power supply can drive and control the macro micro driven linear piezoelectric motor, and realizes quick and seamless switch between macro and micro drive. In addition, the power supply can drive and control the ultrasonic motor or piezoelectric ceramic micro actuator individually. The power supply achieves the multiple parameters of output signals adjustable simultaneously and exhibits good control characteristics.
To investigate a novel macro and micro driven linear piezoelectric motor composed of an ultrasonic motor with macro movement and a piezoelectric actuator with micro movement, a digital signal processing (DSP) based macro and micro power supply is designed, which fits the new linear piezoelectric motor. The power supply comprises a control circuit, a voltage conversion circuit, an amplifier circuit, a half-bridge module, an optical isolators-drive circuit, etc, where the DSP of TMS320F28335 is used as the controller. When the linear piezoelectric motor working in a macro driven state, the power supply outputs alternating currents with high frequency and high voltage, which drives the linear piezoelectric motor dynamically at an ultrasonic frequency; while working in the micro driven state, the power supply outputs direct currents with high voltage, which drives the linear piezoelectric motor in micro driven statically. Here a prototype of the macro-micro power supply is designed. After a series of experiments on the power supply with and without loads, the results show that the power supply can drive and control the macro micro driven linear piezoelectric motor, and realizes quick and seamless switch between macro and micro drive. In addition, the power supply can drive and control the ultrasonic motor or piezoelectric ceramic micro actuator individually. The power supply achieves the multiple parameters of output signals adjustable simultaneously and exhibits good control characteristics.
2017, 34(1):30-36.
DOI: 10.16356/j.1005-1120.2017.01.030
Abstract:
Rotation modulation technique is generally used to improve the performance of aviation and marine inertial navigation system. Considering of the performance requirements from current aerospace to MEMS micro-nano inertial device, this paper proposedrotary inertial device modulation technology application methods on the satellite.Firstly, taking the advantage ofultrasonic motor, like high resolution, fast response, electromagnetic compatibility, a lowmagnetic, high-precision and appropriate for use on satellite ultrasonic motor modulation turntable was developed. Then, through theoretical modeling and simulations,the rotation modulation technology was verified to improvethe precise of satellite attitude measurementeffectively, equivalent toimprove the accuracy of MEMS gyro over an order of magnitude. This work helpsachieve the application of rotation modulation technology in aerospace and acceleratethe promotion of the MEMS gyro in satellite attitude measurement.
Rotation modulation technique is generally used to improve the performance of aviation and marine inertial navigation system. Considering of the performance requirements from current aerospace to MEMS micro-nano inertial device, this paper proposedrotary inertial device modulation technology application methods on the satellite.Firstly, taking the advantage ofultrasonic motor, like high resolution, fast response, electromagnetic compatibility, a lowmagnetic, high-precision and appropriate for use on satellite ultrasonic motor modulation turntable was developed. Then, through theoretical modeling and simulations,the rotation modulation technology was verified to improvethe precise of satellite attitude measurementeffectively, equivalent toimprove the accuracy of MEMS gyro over an order of magnitude. This work helpsachieve the application of rotation modulation technology in aerospace and acceleratethe promotion of the MEMS gyro in satellite attitude measurement.
2017, 34(1):37-42.
DOI: 10.16356/j.1005-1120.2017.01.037
Abstract:
A release method of microobjects is presented based on the piezoelectric vibration. To achieve an effective release, the piezoelectric vibration is added to overcome adhesion force happened in the microoperation. This technique employs inertia force to overcome adhesion force, thereby achieving 90% repeatability with a releasing accuracy of 4±0.5 μm, which was experimentally quantified through the manipulation of 20-80 μm polystyrene spheres under an optical microscope. Experimental results confirmed that this adhesion control technique was independent of substrate. Theoretical analyses were conducted to understand the releasing mechanism. Therefore, the micromanipulation system proved to be effective for active releasing of micromanipulation. A novel gripper structure with triple finger is devised. In the design, three cantilevers are considered as the end effectors of the fingers, driven by piezoelectric ceramic transducer (PZT). Tungsten tipped probes are used to pick and place the micro objects.
A release method of microobjects is presented based on the piezoelectric vibration. To achieve an effective release, the piezoelectric vibration is added to overcome adhesion force happened in the microoperation. This technique employs inertia force to overcome adhesion force, thereby achieving 90% repeatability with a releasing accuracy of 4±0.5 μm, which was experimentally quantified through the manipulation of 20-80 μm polystyrene spheres under an optical microscope. Experimental results confirmed that this adhesion control technique was independent of substrate. Theoretical analyses were conducted to understand the releasing mechanism. Therefore, the micromanipulation system proved to be effective for active releasing of micromanipulation. A novel gripper structure with triple finger is devised. In the design, three cantilevers are considered as the end effectors of the fingers, driven by piezoelectric ceramic transducer (PZT). Tungsten tipped probes are used to pick and place the micro objects.
2017, 34(1):43-48.
DOI: 10.16356/j.1005-1120.2017.01.043
Abstract:
An optimization design for the cylindrical non-contact piezoelectric actuator is presented after analyzing the acoustic radiation pressure and acoustic viscous force. By adding the specific microstructure on the rotor to alter the near-field sound effect and maximize the use of high intensity acoustic field induced by the stator to drive the rotor, the rotor speed is increased. The finite element analysis of the acoustic field induced by a variety of rotors with different structures is conducted, A prototype is manufactured, the speed-test system for the actuator is built, and the driving characteristics are measured. The results suggest that the rotation speed of the rotor can reach 4 167 r/min, which demonstrates that the driving characteristics of cylindrical non-contact piezoelectric actuator are successfully improved using the optimization method proposed.
An optimization design for the cylindrical non-contact piezoelectric actuator is presented after analyzing the acoustic radiation pressure and acoustic viscous force. By adding the specific microstructure on the rotor to alter the near-field sound effect and maximize the use of high intensity acoustic field induced by the stator to drive the rotor, the rotor speed is increased. The finite element analysis of the acoustic field induced by a variety of rotors with different structures is conducted, A prototype is manufactured, the speed-test system for the actuator is built, and the driving characteristics are measured. The results suggest that the rotation speed of the rotor can reach 4 167 r/min, which demonstrates that the driving characteristics of cylindrical non-contact piezoelectric actuator are successfully improved using the optimization method proposed.
2017, 34(1):49-54.
DOI: 10.16356/j.1005-1120.2017.01.049
Abstract:
The high controllability and high resolution control of linear ultrasonic motors depend on effective control of driving signals. For a good control characteristic, step control which the driver output turned off and on was used. Therefore, a novel dual PWM topology structure ultrasonic motor driver was designed and analyzed. According to the characteristics of the circuits, two kinds of hardware turned off methods named methods A and B were discussed. The differences of the voltage applied on motor by different methods were figured out. Finally, a series of experiments were carried out in the clean room to study the influence of step characteristic by different turn off methods. The experimental results show that the steplength was 230 nm by method A and 125 nm by method B, while cycles of driving signals were 6. The method B has a smaller steplength when cycles are 6. The average steplength varies in non-linear while driving cycles changing. The steplength varies approximately in linear while voltage amplitude changing. Therefore, method B is better to implement step control, because it gets a better control in positioning system.
The high controllability and high resolution control of linear ultrasonic motors depend on effective control of driving signals. For a good control characteristic, step control which the driver output turned off and on was used. Therefore, a novel dual PWM topology structure ultrasonic motor driver was designed and analyzed. According to the characteristics of the circuits, two kinds of hardware turned off methods named methods A and B were discussed. The differences of the voltage applied on motor by different methods were figured out. Finally, a series of experiments were carried out in the clean room to study the influence of step characteristic by different turn off methods. The experimental results show that the steplength was 230 nm by method A and 125 nm by method B, while cycles of driving signals were 6. The method B has a smaller steplength when cycles are 6. The average steplength varies in non-linear while driving cycles changing. The steplength varies approximately in linear while voltage amplitude changing. Therefore, method B is better to implement step control, because it gets a better control in positioning system.
2017, 34(1):55-61.
DOI: 10.16356/j.1005-1120.2017.01.055
Abstract:
Piezoelectric friction-inertial motor is known for its promise for a long-range and high-resolution motion. The movement of the slider/rotor of the motor is achieved by stick-slip effect. We report a relaxor-based-ferroelectric-single-crystal cymbal actuator and a miniature piezoelectric friction-inertial linear motor (abbreviated as PFILM) fabricated with the cymbal actuator. The cymbal actuator is fabricated with a 10 mm diameter disk of 0.70Pb(Mg1/3Nb2/3)O3-0.30PbTiO3 single crystal. The displacement of the cymbal actuator increases almost proportionally from 0 to 23 μm with driving voltage up to 500 V, and the minimal hysteresis is observed. The cymbal-PFILM with 20 mm motion range works under driving voltage frequency of ca. 100 Hz to ca. 5 kHz, the fastest speed is obtained with 3.5 kHz and the no-load speed is 14 mm/s and the maximum thrust force is 98 mN. Compared with a PFILM based on multilayer piezoelectric ceramic, the proposed motor has a larger stroke under DC/quasistatic input voltage in fine motion mode, but a smaller driving force in long-travel mode due to lower resonance frequency.
Piezoelectric friction-inertial motor is known for its promise for a long-range and high-resolution motion. The movement of the slider/rotor of the motor is achieved by stick-slip effect. We report a relaxor-based-ferroelectric-single-crystal cymbal actuator and a miniature piezoelectric friction-inertial linear motor (abbreviated as PFILM) fabricated with the cymbal actuator. The cymbal actuator is fabricated with a 10 mm diameter disk of 0.70Pb(Mg1/3Nb2/3)O3-0.30PbTiO3 single crystal. The displacement of the cymbal actuator increases almost proportionally from 0 to 23 μm with driving voltage up to 500 V, and the minimal hysteresis is observed. The cymbal-PFILM with 20 mm motion range works under driving voltage frequency of ca. 100 Hz to ca. 5 kHz, the fastest speed is obtained with 3.5 kHz and the no-load speed is 14 mm/s and the maximum thrust force is 98 mN. Compared with a PFILM based on multilayer piezoelectric ceramic, the proposed motor has a larger stroke under DC/quasistatic input voltage in fine motion mode, but a smaller driving force in long-travel mode due to lower resonance frequency.
2017, 34(1):62-71.
DOI: 10.16356/j.1005-1120.2017.01.062
Abstract:
Let Fq be a finite field with q=pm elements, where p is an odd prime and m is a positive integer. Here, let D0={(x1,x2)∈Fq2\{(0,0)}:Tr(x1pk1+1+x2pk2+1)=c}, where c∈Fq, Tr is the trace function from Fq to Fp and m/(m, k1) is odd, m/(m, k2) is even. Define a p-ary linear code CD=c(a1,a2):(a1,a2)∈Fq2}, where c(a1,a2)=(Tr(a1x1+a2x2))(x1,x2)∈D. At most three-weight distributions of two classes of linear codes are settled.
Let Fq be a finite field with q=pm elements, where p is an odd prime and m is a positive integer. Here, let D0={(x1,x2)∈Fq2\{(0,0)}:Tr(x1pk1+1+x2pk2+1)=c}, where c∈Fq, Tr is the trace function from Fq to Fp and m/(m, k1) is odd, m/(m, k2) is even. Define a p-ary linear code CD=c(a1,a2):(a1,a2)∈Fq2}, where c(a1,a2)=(Tr(a1x1+a2x2))(x1,x2)∈D. At most three-weight distributions of two classes of linear codes are settled.
2017, 34(1):72-80.
DOI: 10.16356/j.1005-1120.2017.01.072
Abstract:
The process inference cannot be achieved effectively by the traditional expert system, while the ontology and semantic technology could provide better solution to the knowledge acquisition and intelligent inference of expert system. The application mode of ontology and semantic technology on the process parameters recommendation are mainly investigated. Firstly, the content about ontology, semantic web rule language (SWRL) rules and the relative inference engine are introduced. Then, the inference method about process based on ontology technology and the SWRL rule is proposed. The construction method of process ontology base and the writing criterion of SWRL rule are described later. Finally, the results of inference are obtained. The mode raised could offer the reference to the construction of process knowledge base as well as the expert system's reusable process rule library.
The process inference cannot be achieved effectively by the traditional expert system, while the ontology and semantic technology could provide better solution to the knowledge acquisition and intelligent inference of expert system. The application mode of ontology and semantic technology on the process parameters recommendation are mainly investigated. Firstly, the content about ontology, semantic web rule language (SWRL) rules and the relative inference engine are introduced. Then, the inference method about process based on ontology technology and the SWRL rule is proposed. The construction method of process ontology base and the writing criterion of SWRL rule are described later. Finally, the results of inference are obtained. The mode raised could offer the reference to the construction of process knowledge base as well as the expert system's reusable process rule library.
2017, 34(1):81-88.
DOI: 10.16356/j.1005-1120.2017.01.081
Abstract:
Micro-diamond films were prepared on YG6 substrate by hot filament chemical vapor deposition method. An innovative micro-diamond coated tool was used to the lap sapphire wafer. The effect of load, rotating speed, and lapping time on material removal rate(MRR) and surface roughness was investigated. The results showed that the best process parameters were 3 N, 100 r/min and 15 min. The surface quality of sapphire improved significantly after lapping. The coating after lapping adhered well and did not show any peeling. The innovative micro-diamond coated tool was feasible and suitable for the lapping of the single crystal sapphire wafer.
Micro-diamond films were prepared on YG6 substrate by hot filament chemical vapor deposition method. An innovative micro-diamond coated tool was used to the lap sapphire wafer. The effect of load, rotating speed, and lapping time on material removal rate(MRR) and surface roughness was investigated. The results showed that the best process parameters were 3 N, 100 r/min and 15 min. The surface quality of sapphire improved significantly after lapping. The coating after lapping adhered well and did not show any peeling. The innovative micro-diamond coated tool was feasible and suitable for the lapping of the single crystal sapphire wafer.
2017, 34(1):89-96.
DOI: 10.16356/j.1005-1120.2017.089
Abstract:
For the charging station construction of electric vehicle, location selecting is a key issue. There are two problems in location selection of the electric vehicle charging station. One is determining the location of charging station; the other is evaluating the location of charging station. To determine the charging station location, an spatial clustering algorithm is proposed and programmed. The example simulation shows the effectiveness of the spatial clustering algorithm. To evaluate the charging station location, a multi-hierarchical fuzzy method is proposed. Based on the location factors of electric vehicle charging station, the hierarchical evaluation structure of electric vehicle charging station location is constructed, including three levels, 4 first-class factors and 14 second-class factors. The fuzzy multi-hierarchical evaluation model and algorithm are built. The analysis results show that the multi-hierarchical fuzzy method can reasonably complete the electric vehicle charging station location evaluation.
For the charging station construction of electric vehicle, location selecting is a key issue. There are two problems in location selection of the electric vehicle charging station. One is determining the location of charging station; the other is evaluating the location of charging station. To determine the charging station location, an spatial clustering algorithm is proposed and programmed. The example simulation shows the effectiveness of the spatial clustering algorithm. To evaluate the charging station location, a multi-hierarchical fuzzy method is proposed. Based on the location factors of electric vehicle charging station, the hierarchical evaluation structure of electric vehicle charging station location is constructed, including three levels, 4 first-class factors and 14 second-class factors. The fuzzy multi-hierarchical evaluation model and algorithm are built. The analysis results show that the multi-hierarchical fuzzy method can reasonably complete the electric vehicle charging station location evaluation.
2017, 34(1):97-104.
DOI: 10.16356/j.1005-1120.2017.097
Abstract:
The prediction of indentation depth of abrasive grain in hydrophilic fixed-abrasive (FA) lapping is crucial for controlling material removal rate and surface quality of the work-piece being machined. By applying the theory of contact mechanics, a theoretical model of the indentation depth of abrasive grain was developed and the relationships between indentation depth and properties of contact pairs and abrasive back-off were studied. Also, the average surface roughness (Ra) of lapped wafer was approximately calculated according to the obtained indentation depth. To verify the rationality of the proposed model, a series of lapping experiments on lithium niobate (LN) wafers were carried out, whose average surface roughness Ra was measured by atomic force microscope (AFM). The experimental results were coincided with the theoretical predictions, verifying the rationality of the proposed model. It is concluded that the indentation depth of the fixed abrasive was primarily affected by the applied load, wafer micro hardness and pad Young's modulus and so on. Moreover,the larger the applied load, the more significant the back-off of the abrasive grain. The model established in this paper is helpful to the design of FA pad and its machining parameters, and the prediction of Ra as well.
The prediction of indentation depth of abrasive grain in hydrophilic fixed-abrasive (FA) lapping is crucial for controlling material removal rate and surface quality of the work-piece being machined. By applying the theory of contact mechanics, a theoretical model of the indentation depth of abrasive grain was developed and the relationships between indentation depth and properties of contact pairs and abrasive back-off were studied. Also, the average surface roughness (Ra) of lapped wafer was approximately calculated according to the obtained indentation depth. To verify the rationality of the proposed model, a series of lapping experiments on lithium niobate (LN) wafers were carried out, whose average surface roughness Ra was measured by atomic force microscope (AFM). The experimental results were coincided with the theoretical predictions, verifying the rationality of the proposed model. It is concluded that the indentation depth of the fixed abrasive was primarily affected by the applied load, wafer micro hardness and pad Young's modulus and so on. Moreover,the larger the applied load, the more significant the back-off of the abrasive grain. The model established in this paper is helpful to the design of FA pad and its machining parameters, and the prediction of Ra as well.
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