Pneumatic artificial muscles(PAMs) have properties similar to biological muscles,which are widely used in robotics as actuators.It is difficult to achieve high-precision position control for robotics system driven by ...Pneumatic artificial muscles(PAMs) have properties similar to biological muscles,which are widely used in robotics as actuators.It is difficult to achieve high-precision position control for robotics system driven by PAMs.A 3-DOF musculoskeletal bionic leg mechanism is presented,which is driven by PAMs for quadruped robots.PAM is used to simulate the compliance of biological muscle.The kinematics of the leg swing is derived,and the foot desired trajectory is planned as the sinusoidal functions.The swing experiments of the musculoskeletal leg mechanism are conducted to analyse the extension and flexion of joints.A proportional integral derivative(PID) algorithm is presented for controlling the flexion/extension of the joint.The trajectory tracking results of joints and the PAM gas pressure are obtained.Experimental results show that the developed leg mechanism exhibits good biological properties.展开更多
A formulation for the coupled analysis of thermo-hydro-mechanical （THM） problems in joints is first presented. The work involves the establishment of equilibrium and mass and energy balance equations. Balance equati...A formulation for the coupled analysis of thermo-hydro-mechanical （THM） problems in joints is first presented. The work involves the establishment of equilibrium and mass and energy balance equations. Balance equations were formulated taking into account two phases： water and air. The joint element developed was implemented in a general purpose finite element computer code for THM analysis of porous media （Code_Bright）. The program was then used to study a number of cases ranging from laboratory tests to large scale in situ tests. A numerical simulation of coupled hydraulic shear tests of rough granite joints is first presented. The tests as well as the model show the coupling between permeability and the deformation of thejoints. The experimental investigation was focused on the effects of suction on the mechanical behaviour of rock joints. Laboratory tests were performed in a direct shear cell equipped with suction control. Suction was imposed using a vapour forced convection circuit connected to the cell and controlled by an air pump. Artificial joints of Lilla claystone were prepared.Joint roughness of varying intensity was created by carving the surfaces in contact in such a manner that rock ridges of different tip angles were formed. These angles ranged from 0° （smooth joint） to 45° （very rough joint profile）. The geometric profiles of the two surfaces in contact were initially positioned in a ＂matching＂ situation. Several tests were performed for different values of suctions （200, 100, and 20 MPa） and for different values of vertical stresses （30, 60, and 150 kPa）. A constitutive model including the effects of suction and joint roughness is proposed to simulate the unsaturated behaviour of rock joints. The new constitutive law was incorporated in the code and experimental results were numerically simulated.展开更多
Some quadruped robots developed recently show better dynamic performance and environmental adaptability than ever, and have been preliminarily applied in the field of emergency disposal, military reconnaissance and in...Some quadruped robots developed recently show better dynamic performance and environmental adaptability than ever, and have been preliminarily applied in the field of emergency disposal, military reconnaissance and infrastructure construction. The development route, mechanisms design, control methods and mobile manipulating approaches of the quadruped robots are surveyed in this article. Firstly, the development route of the quadruped robot is combed, as the references of the forecast of the future work on quadruped robots. Then the bionic structure and the motion control method of the quadruped robot is summarized, the advantages and disadvantages are analyzed in aspects of gait switching, terrain adaption and disturbance resistance. Subsequently, aiming at the mobile manipulation of the quadruped robot, the representative leg-arm collaborative robots and the multi-task-oriented Whole-body Control (WBC) methods are introduced. Finally, the summary and future work of the quadruped robots is given.展开更多
Analyzes the mechanism of overvoltage when contactless tap changer switch which is applied in distributing transformer converted directly.When the device convert the tap off,it employs the way that the SSR is switche...Analyzes the mechanism of overvoltage when contactless tap changer switch which is applied in distributing transformer converted directly.When the device convert the tap off,it employs the way that the SSR is switched on when voltage through zero and switched off when current through zero.But in the experiment we found that overvoltage will occur in the process of changing tap changer.The paper illustrates the mechanism of overvoltage in theory by analyzing the equivalent circuit and using analytic method of transition process.展开更多
Shape memory alloy （SMA） actuator is a potential advanced component for servo- systems of aerospace vehicles and aircraft. This paper presents a joint with two degrees of freedom （DOF） and a mobility range close t...Shape memory alloy （SMA） actuator is a potential advanced component for servo- systems of aerospace vehicles and aircraft. This paper presents a joint with two degrees of freedom （DOF） and a mobility range close to ±60° when driven by SMA triple wires. The fuzzy proportional-integral-derivative （PID）-controlled actuator drive was designed using antagonistic SMA triple wires, and the resistance feedback signal made a closed loop. Experiments showed that, with the driving responding frequency increasing, the overstress became harder to be avoided at the position under the maximum friction force. Furthermore, the hysteresis gap between the heating and cooling paths of the strain-to-resistance curve expanded under this condition. A fuzzy logic control was considered as a solution, and the curves of the wires were then modeled by fitting polynomials so that the measured resistance was used directly to determine the control signal. Accurate control was demonstrated through the step response, and the experimental results showed that under the fuzzy PID-control program, the mean absolute error （MAE） of the rotation angle was about 3.147°. In addition, the investigation of the external interference to the system proved the controllable maximum output.展开更多
为探究短波紫外线(ultraviolet C,UV-C)照射对苹果采后灰霉病的防治效果与抗性诱导机理,以红富士苹果为材料,采用剂量分别为3.5、7.0、10.5 k J/m2的UV-C(280 nm)进行照射,常温条件下放置2 d后接种灰葡萄孢菌,以不经UV-C照射直接接种灰...为探究短波紫外线(ultraviolet C,UV-C)照射对苹果采后灰霉病的防治效果与抗性诱导机理,以红富士苹果为材料,采用剂量分别为3.5、7.0、10.5 k J/m2的UV-C(280 nm)进行照射,常温条件下放置2 d后接种灰葡萄孢菌,以不经UV-C照射直接接种灰葡萄孢菌的果实作为对照。结果表明:照射剂量为3.5 k J/m2和7.0 k J/m2的UV-C照射可显著降低果实灰霉病的发生率,抑制病斑直径的扩展(P<0.01),其中照射剂量为7.0 k J/m2 UV-C处理的效果更好;而照射剂量为10.5 k J/m2的UV-C照射处理在接种后贮藏前期对病害有抑制作用,后期却加快病害发展。3.5 k J/m2和7.0 k J/m2 UV-C处理能诱导苹果果实几丁质酶、β-1,3-葡聚糖酶、过氧化物酶(POD)、多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)等抵御酶活性的提高,诱导酚类物质的合成,进而增强果实的抗病性,其中7.0 k J/m2 UV-C处理诱导效果更明显,与对照差异显著(P<0.01)。10.5 k J/m2 UV-C照射仅在接种后前期诱导POD、PPO、PAL和几丁质酶的活性迅速上升,提高总酚和类黄酮含量,但对β-1,3-葡聚糖酶活性没有诱导作用。展开更多
目的:探讨膝骨关节炎患者体重指数与双下肢力线的关系。方法:2008年7月至2010年6月,收集因膝骨关节炎行全膝关节置换术的膝内翻患者78例,男17例,女61例;年龄41～85岁,平均68.1岁。体重指数采用普通成年人体重指数(body mass index,BMI)...目的:探讨膝骨关节炎患者体重指数与双下肢力线的关系。方法:2008年7月至2010年6月,收集因膝骨关节炎行全膝关节置换术的膝内翻患者78例,男17例,女61例;年龄41～85岁,平均68.1岁。体重指数采用普通成年人体重指数(body mass index,BMI)的分类标准分为3组:正常组,BMI<24.0,男3例,女11例,14例28膝,平均年龄(69.5±4.7)岁;超重组,24.0≤BMI<28.0,男4例,女25例,共29例58膝,平均年龄(66.4±7.9)岁;肥胖组,BMI≥28.0,男10例,女25例,共35例70膝,平均年龄(69.1±8.3)岁。采用躯体X线测量系统测量平卧位和负重位的双下肢力线角度。结果:正常组与超重组患者,平卧位及负重位下肢力线膝内翻角度差异均无统计学意义。肥胖组平卧位膝内翻角度与其他两组差异无统计学意义,负重位膝内翻角度与其他两组差异有统计学意义。体重指数与平卧位和负重位膝内翻角无明显相关性。3组负重位膝内翻角度均大于平卧位。结论:肥胖骨关节炎患者负重位时膝内翻角度增大,提示肥胖是导致下肢力线内翻角度增大的一个重要因素。展开更多
基金Supported by the National Natural Science Foundation of China(No.51375289)Shanghai Municipal National Natural Science Foundation of China(No.13ZR1415500)Innovation Fund of Shanghai Education Commission(No.13YZ020)
文摘Pneumatic artificial muscles(PAMs) have properties similar to biological muscles,which are widely used in robotics as actuators.It is difficult to achieve high-precision position control for robotics system driven by PAMs.A 3-DOF musculoskeletal bionic leg mechanism is presented,which is driven by PAMs for quadruped robots.PAM is used to simulate the compliance of biological muscle.The kinematics of the leg swing is derived,and the foot desired trajectory is planned as the sinusoidal functions.The swing experiments of the musculoskeletal leg mechanism are conducted to analyse the extension and flexion of joints.A proportional integral derivative(PID) algorithm is presented for controlling the flexion/extension of the joint.The trajectory tracking results of joints and the PAM gas pressure are obtained.Experimental results show that the developed leg mechanism exhibits good biological properties.
文摘A formulation for the coupled analysis of thermo-hydro-mechanical （THM） problems in joints is first presented. The work involves the establishment of equilibrium and mass and energy balance equations. Balance equations were formulated taking into account two phases： water and air. The joint element developed was implemented in a general purpose finite element computer code for THM analysis of porous media （Code_Bright）. The program was then used to study a number of cases ranging from laboratory tests to large scale in situ tests. A numerical simulation of coupled hydraulic shear tests of rough granite joints is first presented. The tests as well as the model show the coupling between permeability and the deformation of thejoints. The experimental investigation was focused on the effects of suction on the mechanical behaviour of rock joints. Laboratory tests were performed in a direct shear cell equipped with suction control. Suction was imposed using a vapour forced convection circuit connected to the cell and controlled by an air pump. Artificial joints of Lilla claystone were prepared.Joint roughness of varying intensity was created by carving the surfaces in contact in such a manner that rock ridges of different tip angles were formed. These angles ranged from 0° （smooth joint） to 45° （very rough joint profile）. The geometric profiles of the two surfaces in contact were initially positioned in a ＂matching＂ situation. Several tests were performed for different values of suctions （200, 100, and 20 MPa） and for different values of vertical stresses （30, 60, and 150 kPa）. A constitutive model including the effects of suction and joint roughness is proposed to simulate the unsaturated behaviour of rock joints. The new constitutive law was incorporated in the code and experimental results were numerically simulated.
基金the National Natural Science Founda-tion of China(Grant No.91948201,Grant No.62073191,Grant No.61973135)the Shandong Key R&D Program(No.2019JZZY020317)the Fundamental Research Funds of Shandong University(Grant No.2019GN017).
文摘Some quadruped robots developed recently show better dynamic performance and environmental adaptability than ever, and have been preliminarily applied in the field of emergency disposal, military reconnaissance and infrastructure construction. The development route, mechanisms design, control methods and mobile manipulating approaches of the quadruped robots are surveyed in this article. Firstly, the development route of the quadruped robot is combed, as the references of the forecast of the future work on quadruped robots. Then the bionic structure and the motion control method of the quadruped robot is summarized, the advantages and disadvantages are analyzed in aspects of gait switching, terrain adaption and disturbance resistance. Subsequently, aiming at the mobile manipulation of the quadruped robot, the representative leg-arm collaborative robots and the multi-task-oriented Whole-body Control (WBC) methods are introduced. Finally, the summary and future work of the quadruped robots is given.
基金Harbin science an technology officecontract num ber is 0 0 112 110 98
文摘Analyzes the mechanism of overvoltage when contactless tap changer switch which is applied in distributing transformer converted directly.When the device convert the tap off,it employs the way that the SSR is switched on when voltage through zero and switched off when current through zero.But in the experiment we found that overvoltage will occur in the process of changing tap changer.The paper illustrates the mechanism of overvoltage in theory by analyzing the equivalent circuit and using analytic method of transition process.
基金co-supported by the National Natural Science Foundation of China (61175104)National Science and Technology Support Program of China (2012BA114B01)
文摘Shape memory alloy （SMA） actuator is a potential advanced component for servo- systems of aerospace vehicles and aircraft. This paper presents a joint with two degrees of freedom （DOF） and a mobility range close to ±60° when driven by SMA triple wires. The fuzzy proportional-integral-derivative （PID）-controlled actuator drive was designed using antagonistic SMA triple wires, and the resistance feedback signal made a closed loop. Experiments showed that, with the driving responding frequency increasing, the overstress became harder to be avoided at the position under the maximum friction force. Furthermore, the hysteresis gap between the heating and cooling paths of the strain-to-resistance curve expanded under this condition. A fuzzy logic control was considered as a solution, and the curves of the wires were then modeled by fitting polynomials so that the measured resistance was used directly to determine the control signal. Accurate control was demonstrated through the step response, and the experimental results showed that under the fuzzy PID-control program, the mean absolute error （MAE） of the rotation angle was about 3.147°. In addition, the investigation of the external interference to the system proved the controllable maximum output.
文摘为探究短波紫外线(ultraviolet C,UV-C)照射对苹果采后灰霉病的防治效果与抗性诱导机理,以红富士苹果为材料,采用剂量分别为3.5、7.0、10.5 k J/m2的UV-C(280 nm)进行照射,常温条件下放置2 d后接种灰葡萄孢菌,以不经UV-C照射直接接种灰葡萄孢菌的果实作为对照。结果表明:照射剂量为3.5 k J/m2和7.0 k J/m2的UV-C照射可显著降低果实灰霉病的发生率,抑制病斑直径的扩展(P<0.01),其中照射剂量为7.0 k J/m2 UV-C处理的效果更好;而照射剂量为10.5 k J/m2的UV-C照射处理在接种后贮藏前期对病害有抑制作用,后期却加快病害发展。3.5 k J/m2和7.0 k J/m2 UV-C处理能诱导苹果果实几丁质酶、β-1,3-葡聚糖酶、过氧化物酶(POD)、多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)等抵御酶活性的提高,诱导酚类物质的合成,进而增强果实的抗病性,其中7.0 k J/m2 UV-C处理诱导效果更明显,与对照差异显著(P<0.01)。10.5 k J/m2 UV-C照射仅在接种后前期诱导POD、PPO、PAL和几丁质酶的活性迅速上升,提高总酚和类黄酮含量,但对β-1,3-葡聚糖酶活性没有诱导作用。
文摘目的:探讨膝骨关节炎患者体重指数与双下肢力线的关系。方法:2008年7月至2010年6月,收集因膝骨关节炎行全膝关节置换术的膝内翻患者78例,男17例,女61例;年龄41～85岁,平均68.1岁。体重指数采用普通成年人体重指数(body mass index,BMI)的分类标准分为3组:正常组,BMI<24.0,男3例,女11例,14例28膝,平均年龄(69.5±4.7)岁;超重组,24.0≤BMI<28.0,男4例,女25例,共29例58膝,平均年龄(66.4±7.9)岁;肥胖组,BMI≥28.0,男10例,女25例,共35例70膝,平均年龄(69.1±8.3)岁。采用躯体X线测量系统测量平卧位和负重位的双下肢力线角度。结果:正常组与超重组患者,平卧位及负重位下肢力线膝内翻角度差异均无统计学意义。肥胖组平卧位膝内翻角度与其他两组差异无统计学意义,负重位膝内翻角度与其他两组差异有统计学意义。体重指数与平卧位和负重位膝内翻角无明显相关性。3组负重位膝内翻角度均大于平卧位。结论:肥胖骨关节炎患者负重位时膝内翻角度增大,提示肥胖是导致下肢力线内翻角度增大的一个重要因素。
