In this paper,we propose a fully Soft Bionic Grasping Device(SBGD),which has advantages in automatically adjusting the grasping range,variable stiffness,and controllable bending shape.This device consists of soft grip...In this paper,we propose a fully Soft Bionic Grasping Device(SBGD),which has advantages in automatically adjusting the grasping range,variable stiffness,and controllable bending shape.This device consists of soft gripper structures and a soft bionic bracket structure.We adopt the local thin-walled design in the soft gripper structures.This design improves the grippers’bending efficiency,and imitate human finger’s segmental bending function.In addition,this work also proposes a pneumatic soft bionic bracket structure,which not only can fix grippers,but also can automatically adjust the grasping space by imitating the human adjacent fingers’opening and closing movements.Due to the above advantages,the SBGD can grasp larger or smaller objects than the regular grasping devices.Particularly,to grasp small objects reliably,we further present a new Pinching Grasping(PG)method.The great performance of the fully SBGD is verified by experiments.This work will promote innovative development of the soft bionic grasping robots,and greatly meet the applications of dexterous grasping multi-size and multi-shape objects.展开更多
In this paper,a numerical simulation model of the flow field in a gearbox with an oil volume adjusting device is established for the first time to study its influence on the lubrication characteristics of a high-speed...In this paper,a numerical simulation model of the flow field in a gearbox with an oil volume adjusting device is established for the first time to study its influence on the lubrication characteristics of a high-speed electric multiple unit(EMU)gearbox.The moving particle semi-implicit(MPS)method is used to numerically simulate the internal flow field of the gearbox of the high-speed EMU under working conditions.The effects of the velocity of the high-speed EMU,the immersion depth,and the oil sump temperature on the power loss of the gears and the lubricant quantity of each bearing are studied and provide an effective tool for the quantitative evaluation of the lubrication characteristics of the gearbox.The lubrication characteristics of the gearbox under different working conditions are studied when the oil volume adjusting device is closed and opened.The results show that the oil volume adjusting device mainly changes the amount of lubricant stirred by the output gear by changing the flow rate of lubricant from the cavity pinion(Cavity P)to the cavity gear(Cavity G),and thus affects the power loss of gears and the lubricant quantity of each bearing.展开更多
The separate-layer injection in different interlayers and the injection of the same-molecular-weight polymer so- lution in a layer are necessary in the polymer flooding process because of heterogeneous multilayer sand...The separate-layer injection in different interlayers and the injection of the same-molecular-weight polymer so- lution in a layer are necessary in the polymer flooding process because of heterogeneous multilayer sandstone reservoirs in EOR projects. To alleviate the matching problems between the layer permeability and the injected polymer molecular weight, a molecular weight adjusting device with porous medium was designed on the basis of mechanical degradation principle. In terms of four variables （polymer concentration, pore diameter, length of shear component and flow rate ）, the theological behavior of hydrolyzed polyacrylamide （HPAM） solu- tion flowing through the device was investigated in detail. The change of these variables is able to control the shear rate of HPAM solutions through ceramic foam, and achieve the desired degree of shear degradation and the final theological parameters-viscosity loss, viscoelasticity and pressure drop. Therefore, a linear relationship between viscosity loss and shearing rate was established so as to obtain the targeted viscosity easily. Field tests in the Daqing Oil Field showed that the polymer molecular weight could drop 20% to 50%. In a word, the results could guide the industrial application of the novel device and the further study of polymer degradation flowing through the porous medium.展开更多
A bilayer model with ohmic anode contact and injection limited cathode contact has been proposed to calculate the recombination efficiency and recombination zone width of the device. The effects of the thickness of ho...A bilayer model with ohmic anode contact and injection limited cathode contact has been proposed to calculate the recombination efficiency and recombination zone width of the device. The effects of the thickness of hole transport layer and the barriers of organic/organic interface on the combination efficiency and recombination width have been discussed. It is found that： （1） When the electrons are blocked fully and the holes are not blocked significantly at the organic/organic interface, for a given Lh/L, the recombination efficiency increases with increasing the applied voltage, but at a higher applied voltage, the recombination efficiency decreases with increasing Lh/L; （2） The recombination efficiency increases with increasing applied voltage and Hh＇, and when applied voltage and Hh＇ exceed some value, the recombination efficiency appears as a plateau; （3） The recombination width decreases with increasing the applied voltage and Lh/L. This model might explain the relative experiment phenomena.展开更多
An oscillating buoy wave power device (OD) is a device extracting wave power by an oscillating buoy. Being excited by waves, the buoy heaves up and down to convert wave energy into electricity by means of a mechanical...An oscillating buoy wave power device (OD) is a device extracting wave power by an oscillating buoy. Being excited by waves, the buoy heaves up and down to convert wave energy into electricity by means of a mechanical or hydraulic device. Compared with an Oscillating Water Column (OWC) wave power device, the OD has the same capture width ratio as the OWC does, but much higher secondary conversion efficiency. Moreover, the chamber of the OWC, which is the most expensive and difficult part to be built, is not necessary for the OD, so it is easier to construct an OD. In this paper, a numerical calculation is conducted for an optimal design of the OD firstly, then a model of the device is built and, a model test is carried out in a wave tank. The results show that the total efficiency of the OD is much higher than that of the OWC and that the OD is a promising wave power device.展开更多
Dynamic infrared scene simulation is for discovering and solving the problems encountered in designing, developing and manufacturing infrared imaging guidance weapons. The infrared scene simulation is explored by usin...Dynamic infrared scene simulation is for discovering and solving the problems encountered in designing, developing and manufacturing infrared imaging guidance weapons. The infrared scene simulation is explored by using the digital grayscale modulation method. The infrared image modulation model of a digital micro-mirror device （DMD） is established and then the infrared scene simulator prototype which is based on DMD grayscale modulation is developed. To evaluate its main parameters such as resolution, contrast, minimum temperature difference, gray scale, various DMD subsystems such as signal decoding, image normalization, synchronization drive, pulse width modulation （PWM） and DMD chips are designed. The infrared scene simulator is tested on a certain infrared missile seeker. The test results show preliminarily that the infrared scene simulator has high gray scale, small geometrical distortion and highly resolvable imaging resolution and contrast and yields high-fidelity images, thus being able to meet the requirements for the infrared scene simulation inside a laboratory.展开更多
Due to the well condition and the un-expected imbalance movement of the pumping unit in use, the energy consumes a lot. The existing balancing equipment cannot adjust and monitor the pumping units in real time. Theref...Due to the well condition and the un-expected imbalance movement of the pumping unit in use, the energy consumes a lot. The existing balancing equipment cannot adjust and monitor the pumping units in real time. Therefore this paper introduces the new adaptive balancing equipment—fan-shaped adaptive balancing intelligent device, projects a design of such control system based on PLC, and determines the principle of the control system, the execution software and the design flow. Site commissioning effect on Daqing Oilfield shows this fan-shaped adaptive balancing intelligent device can effectively adjust and monitor the pumping unit in real time, the balance even adjusts from 0.787 to 0.901, and integrated energy saving rate is 14.2%. It is approved that this control device is professionally designed, with strong compatibility, and high reliability.展开更多
The distribution of velocity is one of the basic issues in river dynamics.Based on the experimental data measured by ADV in the flume of State Key Hydraulics Laboratory (SKHL),this paper analyzed the ver- tical distri...The distribution of velocity is one of the basic issues in river dynamics.Based on the experimental data measured by ADV in the flume of State Key Hydraulics Laboratory (SKHL),this paper analyzed the ver- tical distribution of point velocity and the varying law of turbulence intensity in straight mobile compound chan- nel with an asymmetric floodplain.Above certain relative height,the streamwise point velocity follows the loga- rithmic distribution.Below the location,the velocity varies linearly approxim...展开更多
Based on the analysis of forces acting on non-cohesive sediment particle under non-equilibrium con- dition,a vectorial equation of coarse particle movement on arbitrarily riverbed and the mathematical model used to si...Based on the analysis of forces acting on non-cohesive sediment particle under non-equilibrium con- dition,a vectorial equation of coarse particle movement on arbitrarily riverbed and the mathematical model used to simulate river width adjust are developed,some flume experiments for the time evolution of straight river channel are done.展开更多
Major advancements have been made in the field of prosthetics, but devices remain largely out of reach for the amputee population domiciled in the developing nations, which makes up 80% of the entire amputee populatio...Major advancements have been made in the field of prosthetics, but devices remain largely out of reach for the amputee population domiciled in the developing nations, which makes up 80% of the entire amputee population of the world. The amputees are left to contend with low function prosthetics that do not mimic the behavior of the natural lost limb, with the long-term use of such devices leading to physical injury to the user. This work was aimed at developing a low-cost ankle-foot prosthesis that affords the user the opportunity to manually alter the stiffness of the ankle, as well storing energy in a forefoot section to aid push-off in late stance. In this paper, the design and results of structural analysis performed on critical parts of the prosthesis are presented, as well as the future direction of the work.展开更多
In order to address the issues of narrow seeding adjustment range and low accuracy of grain placement in the existing rice seeders,a mechanically and pneumatically adjustable precision hole-type seeder is designed.It ...In order to address the issues of narrow seeding adjustment range and low accuracy of grain placement in the existing rice seeders,a mechanically and pneumatically adjustable precision hole-type seeder is designed.It is primarily composed of a seeding disk,air chamber,seed box,and seed discharge device.The design incorporates a symmetrical structure with dual disks and dual casings,enabling both single-sided and double-sided single-row and synchronized seeding.Based on theoretical analysis of seed charging,seed protection,and seed release,the following parameters were determined:seeding disk diameter of 192 mm,suction hole diameter of 1.48-1.52 mm,suction hole spacing of 3.04-9.41 mm,type hole distribution circle radius of about 62.1-77.0 mm,type hole diameter of 9 mm,stirrer plate length of 4.705-9.410 mm,and stirrer plate inclination angle of 0°-30°.Using a coupled simulation method of EDEM-Fluent,the impact of different type hole distributions,stirrer plate lengths,and inclination angles on seeding performance was analyzed.The results indicate that the main and secondary influencing factors on seed charging qualification rate are type hole diameter,stirrer plate inclination angle,and stirrer plate length.The optimal performance is achieved with a type hole diameter of 6 mm,stirrer plate length of 5 mm,and stirrer plate inclination angle of 10°,resulting in a seed charging qualification rate of 71.42%.Furthermore,Fluent software was utilized to analyze the influence of different suction hole spacings,diameters,and air chamber radii on seeding performance.The results revealed that the suction of rice seeds by the hole can be better realized with a suction hole spacing of 6 mm,a suction hole diameter of 1.5 mm,and an air chamber radius of 62 mm,at which the average negative pressure in the suction hole center was about 2824.56 Pa.A bench test and a field test were further performed on the device.The results showed that increasing the number of type holes and suction holes can contribute to more stable regulation of the seeding amount.The optimal single-sided seed metering could achieve a maximum qualified rate of 82.5%,a missing rate of 12.5%,and a repeating rate of 5%;while the optimal double-sided seed metering could obtain a maximum qualified rate,missing rate,and repeating rate of 72.5%,15%,and 12.5%,respectively.This adjustable precision seeder can meet the requirements of precision sowing of Huanghuazhan rice varieties,and the research findings can provide reference for the structural optimization of precision rice seeders.展开更多
基金This work was funded by the National Natural Science Foundation of Chinaunder Grant 62073305the Fundamental Research Funds for the Central Universities,China University of Geosciences(Wuhan)(Nos.CUG170610 and CUGGC02).
文摘In this paper,we propose a fully Soft Bionic Grasping Device(SBGD),which has advantages in automatically adjusting the grasping range,variable stiffness,and controllable bending shape.This device consists of soft gripper structures and a soft bionic bracket structure.We adopt the local thin-walled design in the soft gripper structures.This design improves the grippers’bending efficiency,and imitate human finger’s segmental bending function.In addition,this work also proposes a pneumatic soft bionic bracket structure,which not only can fix grippers,but also can automatically adjust the grasping space by imitating the human adjacent fingers’opening and closing movements.Due to the above advantages,the SBGD can grasp larger or smaller objects than the regular grasping devices.Particularly,to grasp small objects reliably,we further present a new Pinching Grasping(PG)method.The great performance of the fully SBGD is verified by experiments.This work will promote innovative development of the soft bionic grasping robots,and greatly meet the applications of dexterous grasping multi-size and multi-shape objects.
基金supported by the Natural Science Foundation of Sichuan Province,China(Nos.2022NSFSC0034 and 2022NSFSC1901)the National Railway Group Science and Technology Program(No.N2021J028)+1 种基金the Independent Research and Development Projects of State Key Laboratory of Heavy Duty AC Drive Electric Locomotive Systems Integration(No.R111720H01385)the Independent Research and Development Projects of State Key Laboratory of Traction Power(No.2022TPL-T02),China。
文摘In this paper,a numerical simulation model of the flow field in a gearbox with an oil volume adjusting device is established for the first time to study its influence on the lubrication characteristics of a high-speed electric multiple unit(EMU)gearbox.The moving particle semi-implicit(MPS)method is used to numerically simulate the internal flow field of the gearbox of the high-speed EMU under working conditions.The effects of the velocity of the high-speed EMU,the immersion depth,and the oil sump temperature on the power loss of the gears and the lubricant quantity of each bearing are studied and provide an effective tool for the quantitative evaluation of the lubrication characteristics of the gearbox.The lubrication characteristics of the gearbox under different working conditions are studied when the oil volume adjusting device is closed and opened.The results show that the oil volume adjusting device mainly changes the amount of lubricant stirred by the output gear by changing the flow rate of lubricant from the cavity pinion(Cavity P)to the cavity gear(Cavity G),and thus affects the power loss of gears and the lubricant quantity of each bearing.
基金Supported by the Program for Yangtse River Scholars and Innovative Research Terms in Universities(IRT0936)the National Basic Research Program of China(2009CB219905+2 种基金2009CB219907)the Daqing Oilfield Co.Ltd
文摘The separate-layer injection in different interlayers and the injection of the same-molecular-weight polymer so- lution in a layer are necessary in the polymer flooding process because of heterogeneous multilayer sandstone reservoirs in EOR projects. To alleviate the matching problems between the layer permeability and the injected polymer molecular weight, a molecular weight adjusting device with porous medium was designed on the basis of mechanical degradation principle. In terms of four variables （polymer concentration, pore diameter, length of shear component and flow rate ）, the theological behavior of hydrolyzed polyacrylamide （HPAM） solu- tion flowing through the device was investigated in detail. The change of these variables is able to control the shear rate of HPAM solutions through ceramic foam, and achieve the desired degree of shear degradation and the final theological parameters-viscosity loss, viscoelasticity and pressure drop. Therefore, a linear relationship between viscosity loss and shearing rate was established so as to obtain the targeted viscosity easily. Field tests in the Daqing Oil Field showed that the polymer molecular weight could drop 20% to 50%. In a word, the results could guide the industrial application of the novel device and the further study of polymer degradation flowing through the porous medium.
基金Excellent Youth Foundation of Hunan Province(03JJY1008) Science Foundation for Post-doctorate of China(2004035083)
文摘A bilayer model with ohmic anode contact and injection limited cathode contact has been proposed to calculate the recombination efficiency and recombination zone width of the device. The effects of the thickness of hole transport layer and the barriers of organic/organic interface on the combination efficiency and recombination width have been discussed. It is found that： （1） When the electrons are blocked fully and the holes are not blocked significantly at the organic/organic interface, for a given Lh/L, the recombination efficiency increases with increasing the applied voltage, but at a higher applied voltage, the recombination efficiency decreases with increasing Lh/L; （2） The recombination efficiency increases with increasing applied voltage and Hh＇, and when applied voltage and Hh＇ exceed some value, the recombination efficiency appears as a plateau; （3） The recombination width decreases with increasing the applied voltage and Lh/L. This model might explain the relative experiment phenomena.
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.59979025),the High Tech Research and Development(863)Program(Grant No.2001AA516010)and the Science&Technology Program of Guangdong(C32004)
文摘An oscillating buoy wave power device (OD) is a device extracting wave power by an oscillating buoy. Being excited by waves, the buoy heaves up and down to convert wave energy into electricity by means of a mechanical or hydraulic device. Compared with an Oscillating Water Column (OWC) wave power device, the OD has the same capture width ratio as the OWC does, but much higher secondary conversion efficiency. Moreover, the chamber of the OWC, which is the most expensive and difficult part to be built, is not necessary for the OD, so it is easier to construct an OD. In this paper, a numerical calculation is conducted for an optimal design of the OD firstly, then a model of the device is built and, a model test is carried out in a wave tank. The results show that the total efficiency of the OD is much higher than that of the OWC and that the OD is a promising wave power device.
基金co-supported by China Postdoctoral Science Foundation (20090461314)
文摘Dynamic infrared scene simulation is for discovering and solving the problems encountered in designing, developing and manufacturing infrared imaging guidance weapons. The infrared scene simulation is explored by using the digital grayscale modulation method. The infrared image modulation model of a digital micro-mirror device （DMD） is established and then the infrared scene simulator prototype which is based on DMD grayscale modulation is developed. To evaluate its main parameters such as resolution, contrast, minimum temperature difference, gray scale, various DMD subsystems such as signal decoding, image normalization, synchronization drive, pulse width modulation （PWM） and DMD chips are designed. The infrared scene simulator is tested on a certain infrared missile seeker. The test results show preliminarily that the infrared scene simulator has high gray scale, small geometrical distortion and highly resolvable imaging resolution and contrast and yields high-fidelity images, thus being able to meet the requirements for the infrared scene simulation inside a laboratory.
文摘Due to the well condition and the un-expected imbalance movement of the pumping unit in use, the energy consumes a lot. The existing balancing equipment cannot adjust and monitor the pumping units in real time. Therefore this paper introduces the new adaptive balancing equipment—fan-shaped adaptive balancing intelligent device, projects a design of such control system based on PLC, and determines the principle of the control system, the execution software and the design flow. Site commissioning effect on Daqing Oilfield shows this fan-shaped adaptive balancing intelligent device can effectively adjust and monitor the pumping unit in real time, the balance even adjusts from 0.787 to 0.901, and integrated energy saving rate is 14.2%. It is approved that this control device is professionally designed, with strong compatibility, and high reliability.
基金Supported by Key Project of Chinese.Ministry of Education (03134)
文摘The distribution of velocity is one of the basic issues in river dynamics.Based on the experimental data measured by ADV in the flume of State Key Hydraulics Laboratory (SKHL),this paper analyzed the ver- tical distribution of point velocity and the varying law of turbulence intensity in straight mobile compound chan- nel with an asymmetric floodplain.Above certain relative height,the streamwise point velocity follows the loga- rithmic distribution.Below the location,the velocity varies linearly approxim...
基金Supported by National Natural Science Fund (50279024,50479029)Open Fund of State Key Laboratory of High Speed Flow,Sichuan University (200301)
文摘Based on the analysis of forces acting on non-cohesive sediment particle under non-equilibrium con- dition,a vectorial equation of coarse particle movement on arbitrarily riverbed and the mathematical model used to simulate river width adjust are developed,some flume experiments for the time evolution of straight river channel are done.
文摘Major advancements have been made in the field of prosthetics, but devices remain largely out of reach for the amputee population domiciled in the developing nations, which makes up 80% of the entire amputee population of the world. The amputees are left to contend with low function prosthetics that do not mimic the behavior of the natural lost limb, with the long-term use of such devices leading to physical injury to the user. This work was aimed at developing a low-cost ankle-foot prosthesis that affords the user the opportunity to manually alter the stiffness of the ankle, as well storing energy in a forefoot section to aid push-off in late stance. In this paper, the design and results of structural analysis performed on critical parts of the prosthesis are presented, as well as the future direction of the work.
基金supported by the Outstanding Young and Middle-aged Science and Technology Innovation Team Program of Colleges and Universities of Hubei Province(Grant No.T201934)the Development and Application of Rice and Camellia Fruit Mechanized Short Board Machine(Grant No.HBSNYT202208).
文摘In order to address the issues of narrow seeding adjustment range and low accuracy of grain placement in the existing rice seeders,a mechanically and pneumatically adjustable precision hole-type seeder is designed.It is primarily composed of a seeding disk,air chamber,seed box,and seed discharge device.The design incorporates a symmetrical structure with dual disks and dual casings,enabling both single-sided and double-sided single-row and synchronized seeding.Based on theoretical analysis of seed charging,seed protection,and seed release,the following parameters were determined:seeding disk diameter of 192 mm,suction hole diameter of 1.48-1.52 mm,suction hole spacing of 3.04-9.41 mm,type hole distribution circle radius of about 62.1-77.0 mm,type hole diameter of 9 mm,stirrer plate length of 4.705-9.410 mm,and stirrer plate inclination angle of 0°-30°.Using a coupled simulation method of EDEM-Fluent,the impact of different type hole distributions,stirrer plate lengths,and inclination angles on seeding performance was analyzed.The results indicate that the main and secondary influencing factors on seed charging qualification rate are type hole diameter,stirrer plate inclination angle,and stirrer plate length.The optimal performance is achieved with a type hole diameter of 6 mm,stirrer plate length of 5 mm,and stirrer plate inclination angle of 10°,resulting in a seed charging qualification rate of 71.42%.Furthermore,Fluent software was utilized to analyze the influence of different suction hole spacings,diameters,and air chamber radii on seeding performance.The results revealed that the suction of rice seeds by the hole can be better realized with a suction hole spacing of 6 mm,a suction hole diameter of 1.5 mm,and an air chamber radius of 62 mm,at which the average negative pressure in the suction hole center was about 2824.56 Pa.A bench test and a field test were further performed on the device.The results showed that increasing the number of type holes and suction holes can contribute to more stable regulation of the seeding amount.The optimal single-sided seed metering could achieve a maximum qualified rate of 82.5%,a missing rate of 12.5%,and a repeating rate of 5%;while the optimal double-sided seed metering could obtain a maximum qualified rate,missing rate,and repeating rate of 72.5%,15%,and 12.5%,respectively.This adjustable precision seeder can meet the requirements of precision sowing of Huanghuazhan rice varieties,and the research findings can provide reference for the structural optimization of precision rice seeders.
