The design method of a 6-axis force robot's transducer based on the Stewartplatform is detailed. For this purpose, the sensitivity isotropy evaluation criteria of thetransducer are defined, and by the aid of compu...The design method of a 6-axis force robot's transducer based on the Stewartplatform is detailed. For this purpose, the sensitivity isotropy evaluation criteria of thetransducer are defined, and by the aid of computer, the relationships between the criteria and theparameters of all the transducers based on the Stewart platform are investigated within thegeometric model of the solution space, which can provide the theoretical background for the optimalconstruction design of the 6-axis force transducer related to the sensitivity isotropy.展开更多
The current research of wheel force transducer （WFT） mainly focuses on test signal processing and decoupling methods based on signal itself, while the WFT structure optimization research related to decreasing the ma...The current research of wheel force transducer （WFT） mainly focuses on test signal processing and decoupling methods based on signal itself, while the WFT structure optimization research related to decreasing the mass and increase the natural frequency and comprehen- sive sensitivity is not enough. In order to improve the WFT test accuracy, a structure optimization method based on natural frequency and comprehensive sensitivity indicators is put forward. The WPT with 8-beam elastic body is used for the finite element modeling （FEM）, in which the fol- lowing variations are taken into consideration： the con- nection type of elastic body with modified rim, the number of connection holes, and the respects of strain beam including the shape, the cross sectional area and the length, etc.. The test results shows that the natural frequency of the connecting block type is increased by 65.5% compared with the connecting seat type of elastic body ＆ modified rim, and the main channel sensitivity is improved as well. The results show that the connecting block type will achieve the best comprehensive performance when the number of connecting holes between the elastic body and the modified rim is 20. And the thinner and longer strain beam with smaller cross section area is preferable within the scope of elastic body mechanical strength. This research proposes a novel structure optimization method for WFT which contributes to improve the measurement performance of WFT.展开更多
To solve the difficulty of generating an ideal Bessel beam,an simplified annular transducer model is proposed to study the axial acoustic radiation force(ARF)and the corresponding negative ARF(pulling force)exerted on...To solve the difficulty of generating an ideal Bessel beam,an simplified annular transducer model is proposed to study the axial acoustic radiation force(ARF)and the corresponding negative ARF(pulling force)exerted on centered elastic spheres for acoustic-vortex(AV)beams of arbitrary orders.Based on the theory of acoustic scattering,the axial distributions of the velocity potential and the ARF for AV beams of different orders generated by the annular transducers with different physical sizes are simulated.It is proved that the pulling force can be generated by AV beams of arbitrary orders with multiple axial regions.The pulling force is more likely to exert on the sphere with a smaller k0a(product of the wave number and the radius)for the AV beam with a bigger topological charge due to the strengthened off-axis acoustic scattering.The pulling force decreases with the increase of the axial distance for the sphere with a bigger k0a.More pulling force areas with wider axial regions can be formed by AV beams using a bigger-sized annular transducer.The theoretical results demonstrate the feasibility of generating the pulling force along the axes of AV beams using the experimentally applicable circular array of planar transducers,and suggest application potentials for multi-position stable object manipulations in biomedical engineering.展开更多
Quantitative characterization of the mechanical properties of materials in micro-/nano-scale using depth-sensing indentation technique demands high performance of nanoindentation instruments in use. In this paper, the...Quantitative characterization of the mechanical properties of materials in micro-/nano-scale using depth-sensing indentation technique demands high performance of nanoindentation instruments in use. In this paper, the efforts to calibrate the capacitive force transducer of a commercial nanoindentation instrument are presented, where the quasi-static characteristic of the force transducer has been calibrated by a precise compensation balance with a resolution of ~1 nN. To investigate the dynamic response of the transducer, an electrostatic MEMS (Micro-Electro-Mechanical System) based on nano-force transfer standard with nano-Newton (10-9 Newton) resolution and a bandwidth up to 6 kHz have been employed. Preliminary experimental results indicate that 1) the force transducer under calibration has a probing force uncertainty less than 300 nN (1σ) in the calibration range of 1 mN;2) the transient duration at contact points amounts to 10 seconds;3) the overshoot of engagement is pre-load dependent.展开更多
The monitoring of cutting force in a vibration cutting process has a great significance in the popularization of ultrasonic vibration cutting technology. A new monitoring method of which the cutting force of ultrasoni...The monitoring of cutting force in a vibration cutting process has a great significance in the popularization of ultrasonic vibration cutting technology. A new monitoring method of which the cutting force of ultrasonic elliptic vibration cutting is monitored using the electrical properties of transducer was proposed by studying on the relationship of cutting force, transducer electric impedance and load. A measurement system was designed for the electrical properties of transducer. The feasibility of cutting force monitoring method based on the electrical properties of piezoelectric transducer was proved by the cutting experiments.展开更多
This paper presents a calculation method, and composition of a five-component force test device, to resolve the requirement for solid rocket motor multi-component force test. It compares the difference between two cla...This paper presents a calculation method, and composition of a five-component force test device, to resolve the requirement for solid rocket motor multi-component force test. It compares the difference between two classical algorithms, and summarizes the structure and practical usage of the solid rocket motor multi-component force using soft connection structure measurement. The decoupling method of test data is described, and a reasonable research method for solid rocket motor multi-component force is also given in this paper.展开更多
This paper considers the design of EMAT （Electro-Magnetic Acoustic Transducer） based on numerical simulation. The EMAT consists of an exiting coil and two permanent magnets, which transmits the ultrasonic wave by th...This paper considers the design of EMAT （Electro-Magnetic Acoustic Transducer） based on numerical simulation. The EMAT consists of an exiting coil and two permanent magnets, which transmits the ultrasonic wave by the Lorentz force between the eddy current and the static magnetic field by the magnets. From the experimental result on self-prepared EMATs, the intensity and the directivity of the transmitted wave depend on the widths of the coil and the magnets. By means of EEM analysis the authors attempt to determine the optimal values of the above widths such that both the intensity and the directivity achieve the maximum or allowable performance.展开更多
Agricultural machinery typically requires lower limb actuation forces for operations such as treadling,pedaling and tractor based.However,limited systems exist for assessment of such forces that have ergonomic influen...Agricultural machinery typically requires lower limb actuation forces for operations such as treadling,pedaling and tractor based.However,limited systems exist for assessment of such forces that have ergonomic influence.This study,therefore developed and evaluated a single board computer integrated foot transducer(IFT)and autonomous data logging and visualization systemtomonitor dynamic lower limb exerted forces.The systemconsists of custom developed load sensors sandwiched into foot shaped units that fit operator's both feet.Stamped forces at crank angles for operations typical to pedaling while at height(above ground level)for operation representing typical treadling operations were recorded on-board amemory card and displayed on a liquid crystal display.Evaluations were conducted by imposing external loads that significantly increased(p b 0.05)the foot exerted forces.Force trends were periodic with peaks of 73,85,110.5 and 145.4 N for left foot and 41,50,131.7 and 145.4 N for right foot at loads of 10,30,50 and 70 N,respectively during pedaling operations.Similarly,the left lower actuation limb exerted forces of 139,249 and 255 N at 5,10 and 15 N of imposed loads,respectively during treadling operation.System was also evaluated for tractor operations and exerted forces ranged from 92 to 164 and 107–176 N for clutch pedal engagement at lower to higher tractor speeds on farm and tarmacadam roads,respectively.Similarly,for brake pedal engagement,such forces ranged from106 to 173 and 120–204 N on farm and tarmacadamroads.These forces varied significantly at different forward speeds.Results suggest potential of such system for foot exerted force assessments typical to agricultural machinery systems in real field.Designsmay be evaluated or reconsidered tominimizemusculoskeletal disorder risks during prolonged operations.Work-rest schedules protocols can be developed by ergonomists for safe,efficient and comfortable operations.展开更多
基金This project is supported by National 863 plan(No.512-9804-02)Robotics Laboratory,Chinese Academy of Sciences Foundation, China
文摘The design method of a 6-axis force robot's transducer based on the Stewartplatform is detailed. For this purpose, the sensitivity isotropy evaluation criteria of thetransducer are defined, and by the aid of computer, the relationships between the criteria and theparameters of all the transducers based on the Stewart platform are investigated within thegeometric model of the solution space, which can provide the theoretical background for the optimalconstruction design of the 6-axis force transducer related to the sensitivity isotropy.
基金Supported by Anhui Provincal Natural Science Foundation of China (Grant No. 1608085ME109)National Natural Science Foundation of China (Grant Nos. 51675005, 51105001)State Key Laboratory of Automotive Safety and Energy, Tsinghua University, China (Grant No. KF14022)
文摘The current research of wheel force transducer （WFT） mainly focuses on test signal processing and decoupling methods based on signal itself, while the WFT structure optimization research related to decreasing the mass and increase the natural frequency and comprehen- sive sensitivity is not enough. In order to improve the WFT test accuracy, a structure optimization method based on natural frequency and comprehensive sensitivity indicators is put forward. The WPT with 8-beam elastic body is used for the finite element modeling （FEM）, in which the fol- lowing variations are taken into consideration： the con- nection type of elastic body with modified rim, the number of connection holes, and the respects of strain beam including the shape, the cross sectional area and the length, etc.. The test results shows that the natural frequency of the connecting block type is increased by 65.5% compared with the connecting seat type of elastic body ＆ modified rim, and the main channel sensitivity is improved as well. The results show that the connecting block type will achieve the best comprehensive performance when the number of connecting holes between the elastic body and the modified rim is 20. And the thinner and longer strain beam with smaller cross section area is preferable within the scope of elastic body mechanical strength. This research proposes a novel structure optimization method for WFT which contributes to improve the measurement performance of WFT.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11934009,11974187,and 11604156).
文摘To solve the difficulty of generating an ideal Bessel beam,an simplified annular transducer model is proposed to study the axial acoustic radiation force(ARF)and the corresponding negative ARF(pulling force)exerted on centered elastic spheres for acoustic-vortex(AV)beams of arbitrary orders.Based on the theory of acoustic scattering,the axial distributions of the velocity potential and the ARF for AV beams of different orders generated by the annular transducers with different physical sizes are simulated.It is proved that the pulling force can be generated by AV beams of arbitrary orders with multiple axial regions.The pulling force is more likely to exert on the sphere with a smaller k0a(product of the wave number and the radius)for the AV beam with a bigger topological charge due to the strengthened off-axis acoustic scattering.The pulling force decreases with the increase of the axial distance for the sphere with a bigger k0a.More pulling force areas with wider axial regions can be formed by AV beams using a bigger-sized annular transducer.The theoretical results demonstrate the feasibility of generating the pulling force along the axes of AV beams using the experimentally applicable circular array of planar transducers,and suggest application potentials for multi-position stable object manipulations in biomedical engineering.
文摘Quantitative characterization of the mechanical properties of materials in micro-/nano-scale using depth-sensing indentation technique demands high performance of nanoindentation instruments in use. In this paper, the efforts to calibrate the capacitive force transducer of a commercial nanoindentation instrument are presented, where the quasi-static characteristic of the force transducer has been calibrated by a precise compensation balance with a resolution of ~1 nN. To investigate the dynamic response of the transducer, an electrostatic MEMS (Micro-Electro-Mechanical System) based on nano-force transfer standard with nano-Newton (10-9 Newton) resolution and a bandwidth up to 6 kHz have been employed. Preliminary experimental results indicate that 1) the force transducer under calibration has a probing force uncertainty less than 300 nN (1σ) in the calibration range of 1 mN;2) the transient duration at contact points amounts to 10 seconds;3) the overshoot of engagement is pre-load dependent.
文摘The monitoring of cutting force in a vibration cutting process has a great significance in the popularization of ultrasonic vibration cutting technology. A new monitoring method of which the cutting force of ultrasonic elliptic vibration cutting is monitored using the electrical properties of transducer was proposed by studying on the relationship of cutting force, transducer electric impedance and load. A measurement system was designed for the electrical properties of transducer. The feasibility of cutting force monitoring method based on the electrical properties of piezoelectric transducer was proved by the cutting experiments.
文摘This paper presents a calculation method, and composition of a five-component force test device, to resolve the requirement for solid rocket motor multi-component force test. It compares the difference between two classical algorithms, and summarizes the structure and practical usage of the solid rocket motor multi-component force using soft connection structure measurement. The decoupling method of test data is described, and a reasonable research method for solid rocket motor multi-component force is also given in this paper.
文摘This paper considers the design of EMAT （Electro-Magnetic Acoustic Transducer） based on numerical simulation. The EMAT consists of an exiting coil and two permanent magnets, which transmits the ultrasonic wave by the Lorentz force between the eddy current and the static magnetic field by the magnets. From the experimental result on self-prepared EMATs, the intensity and the directivity of the transmitted wave depend on the widths of the coil and the magnets. By means of EEM analysis the authors attempt to determine the optimal values of the above widths such that both the intensity and the directivity achieve the maximum or allowable performance.
文摘Agricultural machinery typically requires lower limb actuation forces for operations such as treadling,pedaling and tractor based.However,limited systems exist for assessment of such forces that have ergonomic influence.This study,therefore developed and evaluated a single board computer integrated foot transducer(IFT)and autonomous data logging and visualization systemtomonitor dynamic lower limb exerted forces.The systemconsists of custom developed load sensors sandwiched into foot shaped units that fit operator's both feet.Stamped forces at crank angles for operations typical to pedaling while at height(above ground level)for operation representing typical treadling operations were recorded on-board amemory card and displayed on a liquid crystal display.Evaluations were conducted by imposing external loads that significantly increased(p b 0.05)the foot exerted forces.Force trends were periodic with peaks of 73,85,110.5 and 145.4 N for left foot and 41,50,131.7 and 145.4 N for right foot at loads of 10,30,50 and 70 N,respectively during pedaling operations.Similarly,the left lower actuation limb exerted forces of 139,249 and 255 N at 5,10 and 15 N of imposed loads,respectively during treadling operation.System was also evaluated for tractor operations and exerted forces ranged from 92 to 164 and 107–176 N for clutch pedal engagement at lower to higher tractor speeds on farm and tarmacadam roads,respectively.Similarly,for brake pedal engagement,such forces ranged from106 to 173 and 120–204 N on farm and tarmacadamroads.These forces varied significantly at different forward speeds.Results suggest potential of such system for foot exerted force assessments typical to agricultural machinery systems in real field.Designsmay be evaluated or reconsidered tominimizemusculoskeletal disorder risks during prolonged operations.Work-rest schedules protocols can be developed by ergonomists for safe,efficient and comfortable operations.
