A trajectory generator based on vehicle kinematics model was presented and an integrated navigation simulation system was designed.Considering that the tight relation between vehicle motion and topography,a new trajec...A trajectory generator based on vehicle kinematics model was presented and an integrated navigation simulation system was designed.Considering that the tight relation between vehicle motion and topography,a new trajectory generator for vehicle was proposed for more actual simulation.Firstly,a vehicle kinematics model was built based on conversion of attitude vector in different coordinate systems.Then,the principle of common trajectory generators was analyzed.Besides,combining the vehicle kinematics model with the principle of dead reckoning,a new vehicle trajectory generator was presented,which can provide process parameters of carrier anytime and achieve simulation of typical actions of running vehicle.Moreover,IMU(inertial measurement unit) elements were simulated,including accelerometer and gyroscope.After setting up the simulation conditions,the integrated navigation simulation system was verified by final performance test.The result proves the validity and flexibility of this design.展开更多
A novel 6-PSS flexible parallel mechanism was presented,which employed wide-range flexure hinges as passive joints.The proposed mechanism features micron level positioning accuracy over cubic centimeter scale workspac...A novel 6-PSS flexible parallel mechanism was presented,which employed wide-range flexure hinges as passive joints.The proposed mechanism features micron level positioning accuracy over cubic centimeter scale workspace.A three-layer back-propagation(BP) neural network was utilized to the kinematics analysis,in which learning samples containing 1 280 groups of data based on stiffness-matrix method were used to train the BP model.The kinematics performance was accurately calculated by using the constructed BP model with 19 hidden nodes.Compared with the stiffness model,the simulation and numerical results validate that BP model can achieve millisecond level computation time and micron level calculation accuracy.The concept and approach outlined can be extended to a variety of applications.展开更多
The intracontinental subduction of a>200-km-long section of the Tajik-Tarim lithosphere beneath the Pamir Mountains is proposed to explain nearly 30 km of shortening in the Tajik fold-thrust belt and the Pamir upli...The intracontinental subduction of a>200-km-long section of the Tajik-Tarim lithosphere beneath the Pamir Mountains is proposed to explain nearly 30 km of shortening in the Tajik fold-thrust belt and the Pamir uplift.Seismic imaging revealed that the upper slab was scraped and that the lower slab had subducted to a depth of>150 km.These features constitute the tectonic complexity of the Pamirs,as well as the thermal subduction mechanism involved,which remains poorly understood.Hence,in this study,high-resolution three-dimensional(3D)kinematic modeling is applied to investigate the thermal structure and geometry of the subducting slab beneath the Pamirs.The modeled slab configuration reveals distinct along-strike variations,with a steeply dipping slab beneath the southern Pamirs,a more gently inclined slab beneath the northern Pamirs,and apparent upper slab termination at shallow depths beneath the Pamirs.The thermal field reveals a cold slab core after delamination,with temperatures ranging from 400℃to 800℃,enveloped by a hotter mantle reaching~1400℃.The occurrence of intermediate-depth earthquakes aligns primarily with colder slab regions,particularly near the slab tear-off below the southwestern Pamirs,indicating a strong correlation between slab temperature and seismicity.In contrast,the northern Pamirs exhibit reduced seismicity at depth,which is likely associated with thermal weakening and delamination.The central Pamirs show a significant thermal anomaly caused by a concave slab,where the coldest crust does not descend deeply,further suggesting crustal detachment or mechanical failure.The lateral asymmetry in slab temperature possibly explains the mechanism of lateral tearing and differential slab-mantle coupling.展开更多
An instantaneous emission model was developed to model and predict the real driving emissions of the low-speed vehicles. The emission database used in the model was measured by using portable emission measurement syst...An instantaneous emission model was developed to model and predict the real driving emissions of the low-speed vehicles. The emission database used in the model was measured by using portable emission measurement system （PEMS） under actual traffic conditions in the rural area, and the characteristics of the emission data were determined in relation to the driving kinematics （speed and acceleration） of the low-speed vehicle. The input of the emission model is driving cycle, and the model requires instantaneous vehicle speed and acceleration levels as input variables and uses them to interpolate the pollutant emission rate maps to calculate the transient pollutant emission rates, which will be accumulated to calculate the total emissions released during the whole driving cycle. And the vehicle fuel consumption was determined through the carbon balance method. The model predicted the emissions and fuel consumption of an in-use low-speed vehicle type model, which agreed well with the measured data.展开更多
Backswimmers exhibit a high degree of mobility in water,and their different motion patterns have important implications for the design of micro-biomimetic underwater robots.This paper used three-dimensional high-speed...Backswimmers exhibit a high degree of mobility in water,and their different motion patterns have important implications for the design of micro-biomimetic underwater robots.This paper used three-dimensional high-speed cameras to extract the key points on the hind legs.The hind leg motion laws and the deformation laws of the setae were obtained in four motion patterns:rapid forward,cruising,in-motion turning,and in-place turning.The motion laws of each joint on the hind leg are modeled using a Fourier series.A kinematic model of hind legs was established based on the DH method,and the motion characteristics of hind legs under different motion patterns were analyzed.This paper provides basic data and theoretical models for micro-biomimetic robots.展开更多
The design and analysis of continuum robots have consistently been a prominent research focus in the field of mechanics.However,portable continuum robots with minimal spatial occupancy,which have great potential for a...The design and analysis of continuum robots have consistently been a prominent research focus in the field of mechanics.However,portable continuum robots with minimal spatial occupancy,which have great potential for applications such as search and rescue,are scarcely available.This paper presents a novel helical-coiled multi-segment flexible continuum robot featuring helical deployment and compact design,with an integrated framework for structural design,kinematic modeling,and experimental validation.The design of the helical-coiled multi-segment flexible continuum robot for unstructured environment detection,including a flexible body,an actuation module,a feed module,and a sensing module,is presented systematically.Kinematic models of both single-and multisegment continuum robots were established based on the constant curvature model to analyze the parameter mapping relationship from the end-effector position and orientation to the driving inputs.Furthermore,the feedforward motion of the robot was examined,and an uncoiling strategy based on S-curve compensation was employed to complete the kinematic analysis.Finally,the accuracy of the kinematic model considering the active uncoiling feed motion was validated through experimental analysis,demonstrating the motion characteristics of the continuum robot.Altogether,this study provides a framework for the design and analysis of helical-coiled continuum robots.展开更多
The stress-strain curves and microstructure properties of superalloy GH4169 was tested by thermal simulation experiment with different parameters,which were deformation temperature and strain rate and strain and origi...The stress-strain curves and microstructure properties of superalloy GH4169 was tested by thermal simulation experiment with different parameters,which were deformation temperature and strain rate and strain and original grain size.The influence of technology parameters on crystal grain size of dynamic recrystallization（DRC）was analyzed.The kinematics model of superalloy GH4169 was established,in which the relation between grain size of dynamic recrystallization and function Z（Zener-Hollomon）and parameters was described.The dynamics model of superalloy GH4169 was put forward,which described the relation between the quantity of dynamic recrystallization and function Z and parameters.The research results showed that the grain size of dynamic recrystallization increased with increasing the temperature and decreasing the strain rate.And the grain size of DRC bore no relationship to original grain size.And the quantity of dynamic recrystallization decreased with increasing the original grain size.展开更多
Hole drilling or contour milling for the large and complex workpieces such as automobile panels and aircraft fuselages makes a high combined demand on machining accuracy,stiffness and workspace of machining equipment....Hole drilling or contour milling for the large and complex workpieces such as automobile panels and aircraft fuselages makes a high combined demand on machining accuracy,stiffness and workspace of machining equipment.Therefore,a 5-DOF(degrees of freedom)parallel kinematic machine(PKM)with redundant constraints is proposed.Based on the kinematics analysis of the parallel mechanism using intermediate variables,the kinematics problems of the PKM are solved through equivalent kinematics model.The structural stiffness matrix method is adopted to model the stiffness of the parallel mechanism of the PKM,where the stiffness of each joint and branch component is obtained by stiffness formula and finite element analysis.And the stiffness model of the parallel mechanism is improved by correction coefficient matrix,each element of which is constructed as a polynomial function of three independent end variables of the parallel mechanism.The terminal stiffness matrices obtained by simulation result are used to determine the coefficients of polynomial function by least square fitting to describe the correction coefficient over the workspace of the parallel mechanism quantitatively.The experiment results prove that the modification method can greatly improve the stiffness model of the parallel mechanism.To enhance the machining accuracy of the PKM,the proposed kinematics model and the improved stiffness model are utilized to optimize the working stiffness of parallel machine by searching the best relative position of parallel machine and workpiece.A plate workpiece taken as example is examined in the case study section,which demonstrates the effectiveness of optimization method.展开更多
Accurate modeling and simulation of autonomous underwater vehicle （AUV） is essential for autonomous control and maneuverability research. In this paper, a mini AUV- ＂MAUV-Ⅱ＂ was researched and the nonlinear mathe...Accurate modeling and simulation of autonomous underwater vehicle （AUV） is essential for autonomous control and maneuverability research. In this paper, a mini AUV- ＂MAUV-Ⅱ＂ was researched and the nonlinear mathematic model of the AUV in spatial motion was derived based on momentum theorem. The forces acting on AUV were resolved to several modules which were expressed in matrix form. Based on the motion model and combined with virtual reality technology, a motion simulation system was constructed. Considering the characteristic of ＂MAUV-Ⅱ ＂, the heading control and depth control were simulated by adopting S-surface control method. A long distance traveling simulation experiment based on target planning was also done. The simulation results show that the ＂MAUV-Ⅱ＂ has good spatial maneuverability, and verify the feasibility and reliability of control software.展开更多
A deep-sea Manned Submarine Vehicle （MSV） is usually required to move at a low forward speed and a low rotational speed when it executes investigation tasks. In this condition, the motion is in large drift angles, a...A deep-sea Manned Submarine Vehicle （MSV） is usually required to move at a low forward speed and a low rotational speed when it executes investigation tasks. In this condition, the motion is in large drift angles, and the maneuverability hydrodynamic forces cannot be expressed properly in the conventional mathematical model of submersible motion. In this paper, firstly, a general equation of MSV with six-freedom motion is presented, and the numerical simulation of descent/ascent motion and helix motion is conducted to reveal the general maneuver characteristics of MSV. Secondly, according to the data of captive model tests of large drift angles of MSV, the regression analysis of position hydrodynamic forces and rotation hydrodynamic forces is carried out, and the results of regression analysis of maneuverability hydrody- namic characteristics are analyzed to reveal the special maneuver characteristics. Thirdly, a special new mathematical model of MSV with the whole range of drift angles motion is presented, which can be used to predict hydrodynamic performance of motion in the 0° - 180° range of drift angles. The results are applied to the design of maneuverability hydrodynamic forces, development of control system and simulator of a practical MSV.展开更多
Counter-rotating electrochemical machining(CRECM)is a novel electrochemical machining(ECM)method,which can be used to machine convex structures with complex shapes on the outer surface of casings.In this study,the evo...Counter-rotating electrochemical machining(CRECM)is a novel electrochemical machining(ECM)method,which can be used to machine convex structures with complex shapes on the outer surface of casings.In this study,the evolution of the convex structure during CRECM is studied.The complex motion form of CRECM is replaced by an equivalent kinematic model,in which the movement of the cathode tool is realized by matrix equations.The trajectory of the cathode tool center satisfies the Archimedes spiral equation,and the feed depth in adjacent cycles is a constant.The simulation results show that the variations of five quality indexes for the convex structure:as machining time increases,the height increases linearly,and the width reduces linearly,the fillets at the top and root fit the rational function,and the inclination angle of the convex satisfies the exponential function.The current density distributions with different rotation angles is investigated.Owing to the differential distribution of current density on workpiece surface,the convex is manufactured with the cathode window transferring into and out of the processing area.Experimental results agree very well with the simulation,which indicates that the proposed model is effective for prediction the evolution of the convex structure in CRECM.展开更多
A method used to detect anomaly and estimate the state of vehicle in driving was proposed.The kinematics model of the vehicle was constructed and nonholonomic constraint conditions were added,which refer to that once ...A method used to detect anomaly and estimate the state of vehicle in driving was proposed.The kinematics model of the vehicle was constructed and nonholonomic constraint conditions were added,which refer to that once the vehicle encounters the faults that could not be controlled,the constraint conditions are violated.Estimation equations of the velocity errors of the vehicle were given out to estimate the velocity errors of side and forward.So the stability of the whole vehicle could be judged by the velocity errors of the vehicle.Conclusions were validated through the vehicle experiment.This method is based on GPS/INS integrated navigation system,and can provide foundation for fault detections in unmanned autonomous vehicles.展开更多
A new parameter identification method is proposed to solve the slippage problem when tracked mobile robots execute turning motions.Such motion is divided into two states in this paper:pivot turning and coupled turning...A new parameter identification method is proposed to solve the slippage problem when tracked mobile robots execute turning motions.Such motion is divided into two states in this paper:pivot turning and coupled turning between angular velocity and linear velocity.In the processing of pivot turning,the slippage parameters could be obtained by measuring the end point in a square path.In the process of coupled turning,the slippage parameters could be calculated by measuring the perimeter of a circular path and the linear distance between the start and end points.The identification results showed that slippage parameters were affected by velocity.Therefore,a fuzzy rule base was established with the basis on the identification data,and a fuzzy controller was applied to motion control and dead reckoning.This method effectively compensated for errors resulting in unequal tension between the left and right tracks,structural dimensions and slippage.The results demonstrated that the accuracy of robot positioning and control could be substantially improved on a rigid floor.展开更多
The complicated topographies of the deep sea pose significant challenges for the core drilling with the Jiaolong submersible manipulator.To address this problem,we proposed a core-drilling kinematic model and evaluate...The complicated topographies of the deep sea pose significant challenges for the core drilling with the Jiaolong submersible manipulator.To address this problem,we proposed a core-drilling kinematic model and evaluated the core-drilling behavior of the submersible manipulator by comprehensively considering the uncertain posture of the Jiaolong submersible.First,we established a forward kinematic model for the core-drilling task in deep sea,which satisfied the requirement of gravitational-direction core drilling.Based on the forward kinematic equations,we then built a double-redundancy inverse kinematic model,which was able to determine the required motion trajectories of six active joints according to the desired core-drilling trajectory.The core-drilling workspaces and the motions of the Jiaolong submersible manipulator were assessed with several calculation examples.The established forward and inverse kinematic models are constructed with clear analytic equations,and thus are directly applicable to the Jiaolong submersible manipulator-based core-drilling task.展开更多
A method of 3 D kinematics simulation of robot fighting platform （RFP） in virtual environment is proposed with the aim of enhancing vision telepresence. Based on the theory of space coordinate transformation, kinema...A method of 3 D kinematics simulation of robot fighting platform （RFP） in virtual environment is proposed with the aim of enhancing vision telepresence. Based on the theory of space coordinate transformation, kinematics equat!ons of RFP are formulated; followed by applying a method of modeling using 3DMAX software to build an RFP＇s 3D geometric model before a 3D kinematics simulation system of RFP is completed based on virtual reality technology and Open Inventor VC ＋ ＋. Test results have indicated that this system can perform RFP＇s kinematics simulation in virtual environment. It can also imitate RFP＇s motion states and environmental features well. Moreover, not only can better real-time performances and interactions be achieved but also operator＇s vision telepresence be enhanced, therefore this approach may help lay the foundation for the realization of RFP＇s teleoperation with vision telepresence.展开更多
A new kind of eight-wheel lunar rover is developed, which is a complex closed-chain system and has good capabilities of climbing slope, surmounting obstacles and adapting to uneven terrain. In this paper, the mechanic...A new kind of eight-wheel lunar rover is developed, which is a complex closed-chain system and has good capabilities of climbing slope, surmounting obstacles and adapting to uneven terrain. In this paper, the mechanical structure of the novel eight-wheel lunar rover is introduced, forward and inverse kinematic models of the rover are established according to the closed-chain coordinate transformation and instantaneous coincidence coordinate. Based on structural characteristics, its kinetic characteristics are analyzed. Wheel slippages are separated and calculated, and a method for closed-loop control modification using wheel slip estimation during the model establishment is proposed. The results can be applied to the motion control of lunar rover.展开更多
This paper presents a new approach for modeling the human body by considering the motion state and the shape of whole body. The body model consists of a skeleton kinematic model and a surface model. The former is used...This paper presents a new approach for modeling the human body by considering the motion state and the shape of whole body. The body model consists of a skeleton kinematic model and a surface model. The former is used to determine the posture of the body,and the latter is used to generate the body shape according to the given posture. The body surface is reconstructed with multi-segment B-spline surfaces based on the 3D scan data from a real human body.Using only a few joints parameters and the original surface scan data, the various body postures and the shape can be generated easily. The model has a strong potential of being used for ergonomic design,garment design, virtual reality environment, as well as creating human animation, etc.展开更多
The anisotropic continuum stored energy density (ACSED) functional is applied for accurate constitutive modeling of biological tissues and finite element implementation without the isochoric—volumetric split, the ani...The anisotropic continuum stored energy density (ACSED) functional is applied for accurate constitutive modeling of biological tissues and finite element implementation without the isochoric—volumetric split, the anisotropic—isotropic split, or the anisotropic invariant split. Related stress and elasticity tensors in the reference and current configurations are worked out. A new kinematic model is derived based on the tangent Poisson’s ratio as a cubic polynomial function of stretch. The ACSED model, along with the kinematic model, accurately fits uniaxial extension test data for compressible human skin, bovine articular cartilage, and human aorta samples.展开更多
A rock-drilling jumbo is the main piece of tunneling equipment used in the energy and infrastructure industries in various countries.The positioning accuracy of its drilling boom greatly affects tunneling efficiency a...A rock-drilling jumbo is the main piece of tunneling equipment used in the energy and infrastructure industries in various countries.The positioning accuracy of its drilling boom greatly affects tunneling efficiency and section-forming quality of mine roadways and engineering tunnels.In order to improve the drilling-positioning accuracy of a three-boom drilling jumbo,we established a kinematics model of the multi-degree-of-freedom(multi-DOF)multi-boom system,using the improved Denavit-Hartenberg(D-H)method,and obtained the mapping relationship between the end position and the amount of motion of each joint.The error of the inverse kinematics calculation for the drilling boom is estimated by an analytical method and a global search algorithm based on particle swarm optimization(PSO)for a straight blasting hole and an inclined blasting hole.On this basis,we propose a back-propagation(BP)neural network optimized by an improved sparrow search algorithm(ISSA)to predict the positioning error of the drilling booms of a three-boom drilling jumbo.In order to verify the accuracy of the proposed error compensation model,we built an automatic-control test platform for the boom,and carried out a positioning error compensation test on the boom.The results show that the average drilling-positioning error was reduced from 9.79 to 5.92 cm,and the error was reduced by 39.5%.Therefore,the proposed method effectively reduces the positioning error of the drilling boom,and improves the accuracy and efficiency of rock drilling.展开更多
Long-bone fractures are common complaints in orthopedic surgery.In recent years,significant progress has been made in robot-assisted fracture-reduction techniques.As a key medical device for diverse fracture morpholog...Long-bone fractures are common complaints in orthopedic surgery.In recent years,significant progress has been made in robot-assisted fracture-reduction techniques.As a key medical device for diverse fracture morphologies and sites,the design of the reduction robot has a profound impact on the reduction outcomes.However,existing reduction robots have practical limitations and cannot simultaneously satisfy clinical requirements in terms of workspace,force/torque,and structural stiffness.To overcome these problems,we first analyze the potential placement areas and performance requirements of reduction robots according to clinical application scenarios.Subsequently,a 3UPS/S-3P hybrid configuration with decoupled rotational and translational degrees of freedom(DOFs)is proposed,and a kinematic model is derived to achieve the motion characteristics of the remote center of motion(RCM).Furthermore,the structural design of a hybrid reduction robot with an integrated distal clamp and proximal fixator was completed,and a mechanical prototype was constructed.The results of the performance evaluations and static analysis demonstrate that the proposed reduction robot has acceptable workspace,force,and torque performance and excellent structural stiffness.Two clinical case simulations further demonstrated the clinical feasibility of the robot.Finally,preliminary experiments on bone models demonstrated the potential effectiveness of the proposed reduction robot in lower-limb fracture reduction.展开更多
基金Projects(90820302, 60805027, 61175064) supported by the National Natural Science Foundation of ChinaProject(2011ssxt231) supported by the Master Degree Thesis Innovation Project Foundation of Central South University, China+1 种基金Project(200805330005) supported by the Research Fund for the Doctoral Program of Higher Education, ChinaProject(2011FJ4043) supported by the Academician Foundation of Hunan Province, China
文摘A trajectory generator based on vehicle kinematics model was presented and an integrated navigation simulation system was designed.Considering that the tight relation between vehicle motion and topography,a new trajectory generator for vehicle was proposed for more actual simulation.Firstly,a vehicle kinematics model was built based on conversion of attitude vector in different coordinate systems.Then,the principle of common trajectory generators was analyzed.Besides,combining the vehicle kinematics model with the principle of dead reckoning,a new vehicle trajectory generator was presented,which can provide process parameters of carrier anytime and achieve simulation of typical actions of running vehicle.Moreover,IMU(inertial measurement unit) elements were simulated,including accelerometer and gyroscope.After setting up the simulation conditions,the integrated navigation simulation system was verified by final performance test.The result proves the validity and flexibility of this design.
基金Project(2002AA422260) supported by the National High Technology Research and Development Program of ChinaProject(2011-6) supported by CAST-HIT Joint Program,ChinaProject supported by Harbin Institute of Technology (HIT) Overseas Talents Introduction Program,China
文摘A novel 6-PSS flexible parallel mechanism was presented,which employed wide-range flexure hinges as passive joints.The proposed mechanism features micron level positioning accuracy over cubic centimeter scale workspace.A three-layer back-propagation(BP) neural network was utilized to the kinematics analysis,in which learning samples containing 1 280 groups of data based on stiffness-matrix method were used to train the BP model.The kinematics performance was accurately calculated by using the constructed BP model with 19 hidden nodes.Compared with the stiffness model,the simulation and numerical results validate that BP model can achieve millisecond level computation time and micron level calculation accuracy.The concept and approach outlined can be extended to a variety of applications.
基金the Chinese Academy of Sciences Pioneer Hundred Talents Program and the Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0708)supported by a MEXT(Ministry of Education,Culture,Sports,Science and Technology)KAKENHI(Grants-in-Aid for Scientific Research)grant(Grant No.21H05203)Kobe University Strategic International Collaborative Research Grant(Type B Fostering Joint Research).
文摘The intracontinental subduction of a>200-km-long section of the Tajik-Tarim lithosphere beneath the Pamir Mountains is proposed to explain nearly 30 km of shortening in the Tajik fold-thrust belt and the Pamir uplift.Seismic imaging revealed that the upper slab was scraped and that the lower slab had subducted to a depth of>150 km.These features constitute the tectonic complexity of the Pamirs,as well as the thermal subduction mechanism involved,which remains poorly understood.Hence,in this study,high-resolution three-dimensional(3D)kinematic modeling is applied to investigate the thermal structure and geometry of the subducting slab beneath the Pamirs.The modeled slab configuration reveals distinct along-strike variations,with a steeply dipping slab beneath the southern Pamirs,a more gently inclined slab beneath the northern Pamirs,and apparent upper slab termination at shallow depths beneath the Pamirs.The thermal field reveals a cold slab core after delamination,with temperatures ranging from 400℃to 800℃,enveloped by a hotter mantle reaching~1400℃.The occurrence of intermediate-depth earthquakes aligns primarily with colder slab regions,particularly near the slab tear-off below the southwestern Pamirs,indicating a strong correlation between slab temperature and seismicity.In contrast,the northern Pamirs exhibit reduced seismicity at depth,which is likely associated with thermal weakening and delamination.The central Pamirs show a significant thermal anomaly caused by a concave slab,where the coldest crust does not descend deeply,further suggesting crustal detachment or mechanical failure.The lateral asymmetry in slab temperature possibly explains the mechanism of lateral tearing and differential slab-mantle coupling.
基金supported by the State Environmental Protection Department of Public Welfare Projects(201409013)the National Natural Science Foundation of China(No.51576016 and No.41275133)
文摘An instantaneous emission model was developed to model and predict the real driving emissions of the low-speed vehicles. The emission database used in the model was measured by using portable emission measurement system （PEMS） under actual traffic conditions in the rural area, and the characteristics of the emission data were determined in relation to the driving kinematics （speed and acceleration） of the low-speed vehicle. The input of the emission model is driving cycle, and the model requires instantaneous vehicle speed and acceleration levels as input variables and uses them to interpolate the pollutant emission rate maps to calculate the transient pollutant emission rates, which will be accumulated to calculate the total emissions released during the whole driving cycle. And the vehicle fuel consumption was determined through the carbon balance method. The model predicted the emissions and fuel consumption of an in-use low-speed vehicle type model, which agreed well with the measured data.
基金supported by the National Natural Science Foundation of China(52475307)the Shandong Provincial Natural Science Foundation(ZR2023ME041).
文摘Backswimmers exhibit a high degree of mobility in water,and their different motion patterns have important implications for the design of micro-biomimetic underwater robots.This paper used three-dimensional high-speed cameras to extract the key points on the hind legs.The hind leg motion laws and the deformation laws of the setae were obtained in four motion patterns:rapid forward,cruising,in-motion turning,and in-place turning.The motion laws of each joint on the hind leg are modeled using a Fourier series.A kinematic model of hind legs was established based on the DH method,and the motion characteristics of hind legs under different motion patterns were analyzed.This paper provides basic data and theoretical models for micro-biomimetic robots.
基金Supported by National Natural Science Foundation of China(Grant Nos.52305003,52175019)National Key R&D Program of China(Grant No.2023YFD2001100)+2 种基金Beijing Natural Science Foundation(Grant No.L222038)Beijing Nova Programme Interdisciplinary Cooperation Project(Grant No.20240484699)Project“Vice President of Science and Technology”of Changping District of Beijing.
文摘The design and analysis of continuum robots have consistently been a prominent research focus in the field of mechanics.However,portable continuum robots with minimal spatial occupancy,which have great potential for applications such as search and rescue,are scarcely available.This paper presents a novel helical-coiled multi-segment flexible continuum robot featuring helical deployment and compact design,with an integrated framework for structural design,kinematic modeling,and experimental validation.The design of the helical-coiled multi-segment flexible continuum robot for unstructured environment detection,including a flexible body,an actuation module,a feed module,and a sensing module,is presented systematically.Kinematic models of both single-and multisegment continuum robots were established based on the constant curvature model to analyze the parameter mapping relationship from the end-effector position and orientation to the driving inputs.Furthermore,the feedforward motion of the robot was examined,and an uncoiling strategy based on S-curve compensation was employed to complete the kinematic analysis.Finally,the accuracy of the kinematic model considering the active uncoiling feed motion was validated through experimental analysis,demonstrating the motion characteristics of the continuum robot.Altogether,this study provides a framework for the design and analysis of helical-coiled continuum robots.
基金Item Sponsored by National Natural Science Foundation of China(50834008)
文摘The stress-strain curves and microstructure properties of superalloy GH4169 was tested by thermal simulation experiment with different parameters,which were deformation temperature and strain rate and strain and original grain size.The influence of technology parameters on crystal grain size of dynamic recrystallization（DRC）was analyzed.The kinematics model of superalloy GH4169 was established,in which the relation between grain size of dynamic recrystallization and function Z（Zener-Hollomon）and parameters was described.The dynamics model of superalloy GH4169 was put forward,which described the relation between the quantity of dynamic recrystallization and function Z and parameters.The research results showed that the grain size of dynamic recrystallization increased with increasing the temperature and decreasing the strain rate.And the grain size of DRC bore no relationship to original grain size.And the quantity of dynamic recrystallization decreased with increasing the original grain size.
文摘Hole drilling or contour milling for the large and complex workpieces such as automobile panels and aircraft fuselages makes a high combined demand on machining accuracy,stiffness and workspace of machining equipment.Therefore,a 5-DOF(degrees of freedom)parallel kinematic machine(PKM)with redundant constraints is proposed.Based on the kinematics analysis of the parallel mechanism using intermediate variables,the kinematics problems of the PKM are solved through equivalent kinematics model.The structural stiffness matrix method is adopted to model the stiffness of the parallel mechanism of the PKM,where the stiffness of each joint and branch component is obtained by stiffness formula and finite element analysis.And the stiffness model of the parallel mechanism is improved by correction coefficient matrix,each element of which is constructed as a polynomial function of three independent end variables of the parallel mechanism.The terminal stiffness matrices obtained by simulation result are used to determine the coefficients of polynomial function by least square fitting to describe the correction coefficient over the workspace of the parallel mechanism quantitatively.The experiment results prove that the modification method can greatly improve the stiffness model of the parallel mechanism.To enhance the machining accuracy of the PKM,the proposed kinematics model and the improved stiffness model are utilized to optimize the working stiffness of parallel machine by searching the best relative position of parallel machine and workpiece.A plate workpiece taken as example is examined in the case study section,which demonstrates the effectiveness of optimization method.
基金Supported by National Natural Science Foundation under Grant No.50879014
文摘Accurate modeling and simulation of autonomous underwater vehicle （AUV） is essential for autonomous control and maneuverability research. In this paper, a mini AUV- ＂MAUV-Ⅱ＂ was researched and the nonlinear mathematic model of the AUV in spatial motion was derived based on momentum theorem. The forces acting on AUV were resolved to several modules which were expressed in matrix form. Based on the motion model and combined with virtual reality technology, a motion simulation system was constructed. Considering the characteristic of ＂MAUV-Ⅱ ＂, the heading control and depth control were simulated by adopting S-surface control method. A long distance traveling simulation experiment based on target planning was also done. The simulation results show that the ＂MAUV-Ⅱ＂ has good spatial maneuverability, and verify the feasibility and reliability of control software.
基金supported by the National High Technology Research and Development Program of China(863 Program, Grant No.2002AA401002)
文摘A deep-sea Manned Submarine Vehicle （MSV） is usually required to move at a low forward speed and a low rotational speed when it executes investigation tasks. In this condition, the motion is in large drift angles, and the maneuverability hydrodynamic forces cannot be expressed properly in the conventional mathematical model of submersible motion. In this paper, firstly, a general equation of MSV with six-freedom motion is presented, and the numerical simulation of descent/ascent motion and helix motion is conducted to reveal the general maneuver characteristics of MSV. Secondly, according to the data of captive model tests of large drift angles of MSV, the regression analysis of position hydrodynamic forces and rotation hydrodynamic forces is carried out, and the results of regression analysis of maneuverability hydrody- namic characteristics are analyzed to reveal the special maneuver characteristics. Thirdly, a special new mathematical model of MSV with the whole range of drift angles motion is presented, which can be used to predict hydrodynamic performance of motion in the 0° - 180° range of drift angles. The results are applied to the design of maneuverability hydrodynamic forces, development of control system and simulator of a practical MSV.
基金the financial support provided by National Natural Science Foundation of China(51805259)Natural Science Foundation of Jiangsu Province of China(No.BK20180431)+1 种基金Postdoctoral Science Foundation of China(No.2019M661833)Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology and Young Elite Scientists Sponsorship Program by CAST。
文摘Counter-rotating electrochemical machining(CRECM)is a novel electrochemical machining(ECM)method,which can be used to machine convex structures with complex shapes on the outer surface of casings.In this study,the evolution of the convex structure during CRECM is studied.The complex motion form of CRECM is replaced by an equivalent kinematic model,in which the movement of the cathode tool is realized by matrix equations.The trajectory of the cathode tool center satisfies the Archimedes spiral equation,and the feed depth in adjacent cycles is a constant.The simulation results show that the variations of five quality indexes for the convex structure:as machining time increases,the height increases linearly,and the width reduces linearly,the fillets at the top and root fit the rational function,and the inclination angle of the convex satisfies the exponential function.The current density distributions with different rotation angles is investigated.Owing to the differential distribution of current density on workpiece surface,the convex is manufactured with the cathode window transferring into and out of the processing area.Experimental results agree very well with the simulation,which indicates that the proposed model is effective for prediction the evolution of the convex structure in CRECM.
基金Projects(90820302,60805027) supported by the National Natural Science Foundation of ChinaProject(200805330005) supported by Research Fund for Doctoral Program of Higher Education of China+1 种基金Projects(2009FJ4030) supported by Academician Foundation of Hunan Province,ChinaProject supported by the Freedom Explore Program of Central South University,China
文摘A method used to detect anomaly and estimate the state of vehicle in driving was proposed.The kinematics model of the vehicle was constructed and nonholonomic constraint conditions were added,which refer to that once the vehicle encounters the faults that could not be controlled,the constraint conditions are violated.Estimation equations of the velocity errors of the vehicle were given out to estimate the velocity errors of side and forward.So the stability of the whole vehicle could be judged by the velocity errors of the vehicle.Conclusions were validated through the vehicle experiment.This method is based on GPS/INS integrated navigation system,and can provide foundation for fault detections in unmanned autonomous vehicles.
文摘A new parameter identification method is proposed to solve the slippage problem when tracked mobile robots execute turning motions.Such motion is divided into two states in this paper:pivot turning and coupled turning between angular velocity and linear velocity.In the processing of pivot turning,the slippage parameters could be obtained by measuring the end point in a square path.In the process of coupled turning,the slippage parameters could be calculated by measuring the perimeter of a circular path and the linear distance between the start and end points.The identification results showed that slippage parameters were affected by velocity.Therefore,a fuzzy rule base was established with the basis on the identification data,and a fuzzy controller was applied to motion control and dead reckoning.This method effectively compensated for errors resulting in unequal tension between the left and right tracks,structural dimensions and slippage.The results demonstrated that the accuracy of robot positioning and control could be substantially improved on a rigid floor.
基金the National Natural Science Foundation of China(No.52175018)the Key R&D Program of Shandong Province(Major Scientific and Technological Innovation Project)(No.2019JZZY010802),China.
文摘The complicated topographies of the deep sea pose significant challenges for the core drilling with the Jiaolong submersible manipulator.To address this problem,we proposed a core-drilling kinematic model and evaluated the core-drilling behavior of the submersible manipulator by comprehensively considering the uncertain posture of the Jiaolong submersible.First,we established a forward kinematic model for the core-drilling task in deep sea,which satisfied the requirement of gravitational-direction core drilling.Based on the forward kinematic equations,we then built a double-redundancy inverse kinematic model,which was able to determine the required motion trajectories of six active joints according to the desired core-drilling trajectory.The core-drilling workspaces and the motions of the Jiaolong submersible manipulator were assessed with several calculation examples.The established forward and inverse kinematic models are constructed with clear analytic equations,and thus are directly applicable to the Jiaolong submersible manipulator-based core-drilling task.
基金Sponsored by Independent Research Projects of State Key Laboratory (ZDKT08-05)
文摘A method of 3 D kinematics simulation of robot fighting platform （RFP） in virtual environment is proposed with the aim of enhancing vision telepresence. Based on the theory of space coordinate transformation, kinematics equat!ons of RFP are formulated; followed by applying a method of modeling using 3DMAX software to build an RFP＇s 3D geometric model before a 3D kinematics simulation system of RFP is completed based on virtual reality technology and Open Inventor VC ＋ ＋. Test results have indicated that this system can perform RFP＇s kinematics simulation in virtual environment. It can also imitate RFP＇s motion states and environmental features well. Moreover, not only can better real-time performances and interactions be achieved but also operator＇s vision telepresence be enhanced, therefore this approach may help lay the foundation for the realization of RFP＇s teleoperation with vision telepresence.
基金Sponsored by the National Natural Science Foundation of China(Grant No.50975059)the National High-Tech Research and Development Program of China(863 Program)(Grant No.2006AA04Z231)+1 种基金the College Discipline Innovation Wisdom Plan(Grant No.B07018)Development Program of the Excellent Youth Scholars of Harbin Institute of Technology(Grant No.CACZ98504837)
文摘A new kind of eight-wheel lunar rover is developed, which is a complex closed-chain system and has good capabilities of climbing slope, surmounting obstacles and adapting to uneven terrain. In this paper, the mechanical structure of the novel eight-wheel lunar rover is introduced, forward and inverse kinematic models of the rover are established according to the closed-chain coordinate transformation and instantaneous coincidence coordinate. Based on structural characteristics, its kinetic characteristics are analyzed. Wheel slippages are separated and calculated, and a method for closed-loop control modification using wheel slip estimation during the model establishment is proposed. The results can be applied to the motion control of lunar rover.
基金This work was funded by the Science & Technology Development Fund of Shanghai, China( No. 005111081)
文摘This paper presents a new approach for modeling the human body by considering the motion state and the shape of whole body. The body model consists of a skeleton kinematic model and a surface model. The former is used to determine the posture of the body,and the latter is used to generate the body shape according to the given posture. The body surface is reconstructed with multi-segment B-spline surfaces based on the 3D scan data from a real human body.Using only a few joints parameters and the original surface scan data, the various body postures and the shape can be generated easily. The model has a strong potential of being used for ergonomic design,garment design, virtual reality environment, as well as creating human animation, etc.
文摘The anisotropic continuum stored energy density (ACSED) functional is applied for accurate constitutive modeling of biological tissues and finite element implementation without the isochoric—volumetric split, the anisotropic—isotropic split, or the anisotropic invariant split. Related stress and elasticity tensors in the reference and current configurations are worked out. A new kinematic model is derived based on the tangent Poisson’s ratio as a cubic polynomial function of stretch. The ACSED model, along with the kinematic model, accurately fits uniaxial extension test data for compressible human skin, bovine articular cartilage, and human aorta samples.
基金National Natural Science Foundation of China(No.12472038)Natural Science Foundation of Jiangsu Province(No.BK20230688)+2 种基金Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.22KJB440004)Key Research and Development Program of Xuzhou(No.KC22404)Research Fund for Doctoral Degree Teachers of Jiangsu Normal University of China(No.22XFRS011).
文摘A rock-drilling jumbo is the main piece of tunneling equipment used in the energy and infrastructure industries in various countries.The positioning accuracy of its drilling boom greatly affects tunneling efficiency and section-forming quality of mine roadways and engineering tunnels.In order to improve the drilling-positioning accuracy of a three-boom drilling jumbo,we established a kinematics model of the multi-degree-of-freedom(multi-DOF)multi-boom system,using the improved Denavit-Hartenberg(D-H)method,and obtained the mapping relationship between the end position and the amount of motion of each joint.The error of the inverse kinematics calculation for the drilling boom is estimated by an analytical method and a global search algorithm based on particle swarm optimization(PSO)for a straight blasting hole and an inclined blasting hole.On this basis,we propose a back-propagation(BP)neural network optimized by an improved sparrow search algorithm(ISSA)to predict the positioning error of the drilling booms of a three-boom drilling jumbo.In order to verify the accuracy of the proposed error compensation model,we built an automatic-control test platform for the boom,and carried out a positioning error compensation test on the boom.The results show that the average drilling-positioning error was reduced from 9.79 to 5.92 cm,and the error was reduced by 39.5%.Therefore,the proposed method effectively reduces the positioning error of the drilling boom,and improves the accuracy and efficiency of rock drilling.
基金Supported by National Natural Science Foundation of China(Grant Nos.52405001,52175001,62373010,82472537)China Postdoctoral Science Foundation(Grant No.2024M760166)+2 种基金Postdoctoral Fellowship Program of CPSF(Grant No.GZC20230186)Shenzhen Municipal Science,Technology,and Innovation Commission(Grant No.SGDX20220530111005036)Beijing Natural Science Foundation(Grant Nos.3222002,3232004,L222061).
文摘Long-bone fractures are common complaints in orthopedic surgery.In recent years,significant progress has been made in robot-assisted fracture-reduction techniques.As a key medical device for diverse fracture morphologies and sites,the design of the reduction robot has a profound impact on the reduction outcomes.However,existing reduction robots have practical limitations and cannot simultaneously satisfy clinical requirements in terms of workspace,force/torque,and structural stiffness.To overcome these problems,we first analyze the potential placement areas and performance requirements of reduction robots according to clinical application scenarios.Subsequently,a 3UPS/S-3P hybrid configuration with decoupled rotational and translational degrees of freedom(DOFs)is proposed,and a kinematic model is derived to achieve the motion characteristics of the remote center of motion(RCM).Furthermore,the structural design of a hybrid reduction robot with an integrated distal clamp and proximal fixator was completed,and a mechanical prototype was constructed.The results of the performance evaluations and static analysis demonstrate that the proposed reduction robot has acceptable workspace,force,and torque performance and excellent structural stiffness.Two clinical case simulations further demonstrated the clinical feasibility of the robot.Finally,preliminary experiments on bone models demonstrated the potential effectiveness of the proposed reduction robot in lower-limb fracture reduction.
