This paper investigates the steady-state availability of a repairable series-parallel system with redundant dependency.The different types of components and repairmen are taken into account,the failure rate of the ope...This paper investigates the steady-state availability of a repairable series-parallel system with redundant dependency.The different types of components and repairmen are taken into account,the failure rate of the operating component varies as the number of other failed components and the repair rate of the failed component is constant in each parallel redundant subsystem.To quantify the redundant dependency,a modified failure dependence function is introduced to determine the failure rate of the components in each subsystem.Markov theory and matrix analysis method are used to get the steady-state probability vector of each subsystem and the steady-state availability of the entire system.A numerical example is presented to illustrate the obtained results and to analyze the effect of redundant dependency class on the system availability.展开更多
It is an urgent problem for robots to operate complex tasks with some unknown motion mechanisms caused by the strong coupling of force and motion. However, humans can perform complex tasks well due to their natural ev...It is an urgent problem for robots to operate complex tasks with some unknown motion mechanisms caused by the strong coupling of force and motion. However, humans can perform complex tasks well due to their natural evolution and postnatal training. A novel biomimetic control method based on a human motion mechanism with high movement adaptability is proposed in this paper. The core is to present a novel variable-parameter compliance controller based on human operation mechanisms with an action-planning method derived from optimization by human motion, and the main contribution is to change the parameters of compliance controller according to human operating intention synchronized with humanoid motion;this change could establish a humanoid map between the force and motion for a seven degree-of-freedom redundant manipulator to deal with the unknown motion mechanism in complex tasks, so the redundant manipulator can operate complex tasks with high performance. Sufficient experiments were performed, and the results validated the effectiveness of the proposed algorithm.展开更多
Redundant robotic arm models as a control object discussed.Background of computational intelligence IT on soft computing optimizer of knowledge base in smart robotic manipulators introduced.Soft computing optimizer is...Redundant robotic arm models as a control object discussed.Background of computational intelligence IT on soft computing optimizer of knowledge base in smart robotic manipulators introduced.Soft computing optimizer is the sophisticated computational intelligence toolkit of deep machine learning SW platform with optimal fuzzy neural network structure.The methods for development and design technology of control systems based on soft computing introduced in this Part 1 allow one to implement the principle of design an optimal intelligent control systems with a maximum reliability and controllability level of a complex control object under conditions of uncertainty in the source data,and in the presence of stochastic noises of various physical and statistical characters.The knowledge bases formed with the application of soft computing optimizer produce robust control laws for the schedule of time dependent coefficient gains of conventional PID controllers for a wide range of external perturbations and are maximally insensitive to random variations of the structure of control object.The robustness is achieved by application a vector fitness function for genetic algorithm,whose one component describes the physical principle of minimum production of generalized entropy both in the control object and the control system,and the other components describe conventional control objective functionals such as minimum control error,etc.The application of soft computing technologies(Part I)for the development a robust intelligent control system that solving the problem of precision positioning redundant(3DOF and 7 DOF)manipulators considered.Application of quantum soft computing in robust intelligent control of smart manipulators in Part II described.展开更多
A super redundant serpentine manipulator has slender structure and multiple degrees of freedom.It can travel through narrow spaces and move in complex spaces.This manipulator is composed of many modules that can form ...A super redundant serpentine manipulator has slender structure and multiple degrees of freedom.It can travel through narrow spaces and move in complex spaces.This manipulator is composed of many modules that can form different lengths of robot arms for different application sites.The increase in degrees of freedom causes the inverse kinematics of redundant manipulator to be typical and immensely increases the calculation load in the joint space.This paper presents an integrated optimization method to solve the path planning for obstacle avoidance and discrete trajectory tracking of a super redundant manipulator.In this integrated optimization,path planning is established on a Bezier curve,and particle swarm optimization is adopted to adjust the control points of the Bezier curve with the kinematic constraints of manipulator.A feasible obstacle avoidance path is obtained along with a discrete trajectory tracking by using a follow-the-leader strategy.The relative distance between each two discrete path points is limited to reduce the fitting error of the connecting rigid links to the smooth curve.Simulation results show that this integrated optimization method can rapidly search for the appropriate trajectory to guide the manipulator in obtaining the target while achieving obstacle avoidance and meeting joint constraints.The proposed algorithm is suitable for 3D space obstacle avoidance and multitarget path tracking.展开更多
Since traditional fault tolerance methods of electronic systems are based on redundant fault tolerance technique,and their structures are fixed when circuits are designed,the self-adaptive ability is limited.In order ...Since traditional fault tolerance methods of electronic systems are based on redundant fault tolerance technique,and their structures are fixed when circuits are designed,the self-adaptive ability is limited.In order to solve these problems,a novel circuit self-adaptive design technique based on evolvable hardware(EHW)is proposed.It features robustness,self-organization and self-adaption.It can be adapted to a complex environment through dynamic configuration of the circuit.In this paper,the proposed technique simulated.The consumption of hardware resources and the number of convergence iterations researched.The effectiveness and superiority of the proposed technique are verified.The designed circuit has the ability of resistible redundant-state interference(RRSI).The proposed technique has a broad application prospect,and it has great significance.展开更多
The parallel spindle heads with high rotational capability are demanded in the area of multi-axis machine tools and 3D printers.This paper focuses on designing a class of 2R1T(R:Rotation;T:Translation)parallel spindle...The parallel spindle heads with high rotational capability are demanded in the area of multi-axis machine tools and 3D printers.This paper focuses on designing a class of 2R1T(R:Rotation;T:Translation)parallel spindle heads and the corresponding collaborative 5-axis manipulators with 2-dimension(2D)large rotational angles.In order to construct 2D rotational degrees of freedom(DOFs),a platform with 2D revolute joints is proposed first.Based on the constraint screw theory,the feasible limbs that can be connected in the platform are synthesized.In order to provide constant rotational axis for the platform,a class of redundant limbs are designed.A class of redundant 2R1T parallel spindle heads is obtained by connecting the redundant limbs with the platform and the redundant characteristics are verified by the modified Grübler-Kutzbach criterion.The corresponding 5-axis collaborative manipulators are presented by constructing a 2-DOF series translational bottom moving platform.The inverse kinematics and the orientation workspace as well as the decoupling characteristics of this type of 2R1T parallel spindle heads are analyzed.The results show that these manipulators have large 2D rotational angles than the traditional A3/Z3 heads and can be potentially used in the application of multi-axis machine tools and the 3D printers.展开更多
Starting from the characteristics of fruit picking,the characteristics of fruit picking robot manipulators and the research state at home and abroad are reviewed.The analysis summarizes the difficulties in fruit picki...Starting from the characteristics of fruit picking,the characteristics of fruit picking robot manipulators and the research state at home and abroad are reviewed.The analysis summarizes the difficulties in fruit picking robotic arm research.Aiming at the configuration of the manipulator,the structure and characteristics of the manipulator with redundant degrees of freedom are introduced,and the feasibility of the redundant mechanism is demonstrated through the current research state of the manipulator.展开更多
为解决波达方向(Direction Of Arrival,DOA)估计方法在阵元失效条件下性能下降甚至失效的问题,本文提出一种基于Toeplitz协方差矩阵重构的DOA估计方法.首先,提出了一种失效阵元检测方法,并根据阵列的鲁棒性将失效阵元分为冗余阵元失效...为解决波达方向(Direction Of Arrival,DOA)估计方法在阵元失效条件下性能下降甚至失效的问题,本文提出一种基于Toeplitz协方差矩阵重构的DOA估计方法.首先,提出了一种失效阵元检测方法,并根据阵列的鲁棒性将失效阵元分为冗余阵元失效和非冗余阵元失效两种情况.然后,分别针对两种失效场景提出相应DOA估计方法:一是冗余阵元失效,利用阵列冗余度,结合差联合阵列对失效阵元进行填充;二是非冗余阵元失效,利用阵列冗余度进行填充后仍存在空洞,结合矩阵填充理论,用迹范数代替秩范数进行凸松弛以恢复协方差矩阵,进而实现对虚拟阵元空洞的填充,恢复阵列自由度.相对于稀疏类算法,有效消除了模型失配的影响.最后,基于子空间方法进行DOA估计.理论和仿真结果表明,相对于现有方法,本文方法有效避免了阵元失效的影响,提高了估计精度.展开更多
With the advancements in nuclear energy,methods that can accurately obtain the spatial information of radioactive sources have become essential for nuclear energy safety.Coded aperture imaging technology is widely use...With the advancements in nuclear energy,methods that can accurately obtain the spatial information of radioactive sources have become essential for nuclear energy safety.Coded aperture imaging technology is widely used because it provides two-dimensional distribution information of radioactive sources.The coded array is a major component of a coded aperture gamma camera,and it affects the key performance parameters of the camera.Currently,commonly used coded arrays such as uniformly redundant arrays(URAs)and modified uniformly redundant arrays(MURAs)have prime numbers of rows or columns and may lead to wastage of detector pixels.A 16×16 coded array was designed on the basis of an existing 16×16 multi-pixel position-sensitive cadmium zinc telluride detector.The digital signal-to-noise(SNR)ratio of the point spread function at the center of the array is 25.67.Furthermore,Monte Carlo camera models and experimental devices based on rank-13 MURA and rank-16 URA have been constructed.With the same angular resolution,the field size of view under rank-16 URA is 1.53 times that of under rank-13 MURA.Simulations(Am-241,Co-57,Ir-192,Cs-137)and experiments(Co-57)are conducted to compare the imaging performance between rank-16 URA and rank-13 MURA.The contrast-to-noise ratio of the reconstructed image of the rank-16 array is great and only slightly lower than that of rank-13 MURA.However,as the photon energy increases,the gap becomes almost negligible.展开更多
基金supported in part by the Natural Science Foundation of Hebei Province under Grant No.A2018203088the National Natural Science Foundation of China under Grant No.11601469the Science Research Project of Education Department of Hebei Province under Grant No.ZD2017079。
文摘This paper investigates the steady-state availability of a repairable series-parallel system with redundant dependency.The different types of components and repairmen are taken into account,the failure rate of the operating component varies as the number of other failed components and the repair rate of the failed component is constant in each parallel redundant subsystem.To quantify the redundant dependency,a modified failure dependence function is introduced to determine the failure rate of the components in each subsystem.Markov theory and matrix analysis method are used to get the steady-state probability vector of each subsystem and the steady-state availability of the entire system.A numerical example is presented to illustrate the obtained results and to analyze the effect of redundant dependency class on the system availability.
基金This work was supported by the National Key Research and Development Program of China(Grant No.2018YFB1305300)the Key Program of the National Natural Science Foundation of China(Grant Nos.61733001,U1713215)the National Natural Science Foundation of China(Grant Nos.61573063,61873039).
文摘It is an urgent problem for robots to operate complex tasks with some unknown motion mechanisms caused by the strong coupling of force and motion. However, humans can perform complex tasks well due to their natural evolution and postnatal training. A novel biomimetic control method based on a human motion mechanism with high movement adaptability is proposed in this paper. The core is to present a novel variable-parameter compliance controller based on human operation mechanisms with an action-planning method derived from optimization by human motion, and the main contribution is to change the parameters of compliance controller according to human operating intention synchronized with humanoid motion;this change could establish a humanoid map between the force and motion for a seven degree-of-freedom redundant manipulator to deal with the unknown motion mechanism in complex tasks, so the redundant manipulator can operate complex tasks with high performance. Sufficient experiments were performed, and the results validated the effectiveness of the proposed algorithm.
文摘Redundant robotic arm models as a control object discussed.Background of computational intelligence IT on soft computing optimizer of knowledge base in smart robotic manipulators introduced.Soft computing optimizer is the sophisticated computational intelligence toolkit of deep machine learning SW platform with optimal fuzzy neural network structure.The methods for development and design technology of control systems based on soft computing introduced in this Part 1 allow one to implement the principle of design an optimal intelligent control systems with a maximum reliability and controllability level of a complex control object under conditions of uncertainty in the source data,and in the presence of stochastic noises of various physical and statistical characters.The knowledge bases formed with the application of soft computing optimizer produce robust control laws for the schedule of time dependent coefficient gains of conventional PID controllers for a wide range of external perturbations and are maximally insensitive to random variations of the structure of control object.The robustness is achieved by application a vector fitness function for genetic algorithm,whose one component describes the physical principle of minimum production of generalized entropy both in the control object and the control system,and the other components describe conventional control objective functionals such as minimum control error,etc.The application of soft computing technologies(Part I)for the development a robust intelligent control system that solving the problem of precision positioning redundant(3DOF and 7 DOF)manipulators considered.Application of quantum soft computing in robust intelligent control of smart manipulators in Part II described.
基金Supported by National Natural Science Foundation of China(Grant No.61733017)Foundation of State Key Laboratory of Robotics of China(Grant No.2018O13)Shanghai Pujiang Program of China(Grant No.18PJD018).
文摘A super redundant serpentine manipulator has slender structure and multiple degrees of freedom.It can travel through narrow spaces and move in complex spaces.This manipulator is composed of many modules that can form different lengths of robot arms for different application sites.The increase in degrees of freedom causes the inverse kinematics of redundant manipulator to be typical and immensely increases the calculation load in the joint space.This paper presents an integrated optimization method to solve the path planning for obstacle avoidance and discrete trajectory tracking of a super redundant manipulator.In this integrated optimization,path planning is established on a Bezier curve,and particle swarm optimization is adopted to adjust the control points of the Bezier curve with the kinematic constraints of manipulator.A feasible obstacle avoidance path is obtained along with a discrete trajectory tracking by using a follow-the-leader strategy.The relative distance between each two discrete path points is limited to reduce the fitting error of the connecting rigid links to the smooth curve.Simulation results show that this integrated optimization method can rapidly search for the appropriate trajectory to guide the manipulator in obtaining the target while achieving obstacle avoidance and meeting joint constraints.The proposed algorithm is suitable for 3D space obstacle avoidance and multitarget path tracking.
基金This work was supported by National Natural Science Foundation of China(Nos.61271153 and 61372039).
文摘Since traditional fault tolerance methods of electronic systems are based on redundant fault tolerance technique,and their structures are fixed when circuits are designed,the self-adaptive ability is limited.In order to solve these problems,a novel circuit self-adaptive design technique based on evolvable hardware(EHW)is proposed.It features robustness,self-organization and self-adaption.It can be adapted to a complex environment through dynamic configuration of the circuit.In this paper,the proposed technique simulated.The consumption of hardware resources and the number of convergence iterations researched.The effectiveness and superiority of the proposed technique are verified.The designed circuit has the ability of resistible redundant-state interference(RRSI).The proposed technique has a broad application prospect,and it has great significance.
基金The authors gratefully acknowledge the financial support of the National Nature Science Foundation of China(Grant Nos.51975039 and 51675037)the Fundamental Research Funds for the Central Universities(Grant No.2018JBZ007).
文摘The parallel spindle heads with high rotational capability are demanded in the area of multi-axis machine tools and 3D printers.This paper focuses on designing a class of 2R1T(R:Rotation;T:Translation)parallel spindle heads and the corresponding collaborative 5-axis manipulators with 2-dimension(2D)large rotational angles.In order to construct 2D rotational degrees of freedom(DOFs),a platform with 2D revolute joints is proposed first.Based on the constraint screw theory,the feasible limbs that can be connected in the platform are synthesized.In order to provide constant rotational axis for the platform,a class of redundant limbs are designed.A class of redundant 2R1T parallel spindle heads is obtained by connecting the redundant limbs with the platform and the redundant characteristics are verified by the modified Grübler-Kutzbach criterion.The corresponding 5-axis collaborative manipulators are presented by constructing a 2-DOF series translational bottom moving platform.The inverse kinematics and the orientation workspace as well as the decoupling characteristics of this type of 2R1T parallel spindle heads are analyzed.The results show that these manipulators have large 2D rotational angles than the traditional A3/Z3 heads and can be potentially used in the application of multi-axis machine tools and the 3D printers.
基金National Natural Science Foundation of China(51305402)。
文摘Starting from the characteristics of fruit picking,the characteristics of fruit picking robot manipulators and the research state at home and abroad are reviewed.The analysis summarizes the difficulties in fruit picking robotic arm research.Aiming at the configuration of the manipulator,the structure and characteristics of the manipulator with redundant degrees of freedom are introduced,and the feasibility of the redundant mechanism is demonstrated through the current research state of the manipulator.
文摘为解决波达方向(Direction Of Arrival,DOA)估计方法在阵元失效条件下性能下降甚至失效的问题,本文提出一种基于Toeplitz协方差矩阵重构的DOA估计方法.首先,提出了一种失效阵元检测方法,并根据阵列的鲁棒性将失效阵元分为冗余阵元失效和非冗余阵元失效两种情况.然后,分别针对两种失效场景提出相应DOA估计方法:一是冗余阵元失效,利用阵列冗余度,结合差联合阵列对失效阵元进行填充;二是非冗余阵元失效,利用阵列冗余度进行填充后仍存在空洞,结合矩阵填充理论,用迹范数代替秩范数进行凸松弛以恢复协方差矩阵,进而实现对虚拟阵元空洞的填充,恢复阵列自由度.相对于稀疏类算法,有效消除了模型失配的影响.最后,基于子空间方法进行DOA估计.理论和仿真结果表明,相对于现有方法,本文方法有效避免了阵元失效的影响,提高了估计精度.
基金supported by the National Natural Science Foundation of China(No.11675078)the Primary Research and Development Plan of Jiangsu Province(No.BE2017729)the Foundation of Graduate Innovation Center in NUAA(No.kfjj20190614)。
文摘With the advancements in nuclear energy,methods that can accurately obtain the spatial information of radioactive sources have become essential for nuclear energy safety.Coded aperture imaging technology is widely used because it provides two-dimensional distribution information of radioactive sources.The coded array is a major component of a coded aperture gamma camera,and it affects the key performance parameters of the camera.Currently,commonly used coded arrays such as uniformly redundant arrays(URAs)and modified uniformly redundant arrays(MURAs)have prime numbers of rows or columns and may lead to wastage of detector pixels.A 16×16 coded array was designed on the basis of an existing 16×16 multi-pixel position-sensitive cadmium zinc telluride detector.The digital signal-to-noise(SNR)ratio of the point spread function at the center of the array is 25.67.Furthermore,Monte Carlo camera models and experimental devices based on rank-13 MURA and rank-16 URA have been constructed.With the same angular resolution,the field size of view under rank-16 URA is 1.53 times that of under rank-13 MURA.Simulations(Am-241,Co-57,Ir-192,Cs-137)and experiments(Co-57)are conducted to compare the imaging performance between rank-16 URA and rank-13 MURA.The contrast-to-noise ratio of the reconstructed image of the rank-16 array is great and only slightly lower than that of rank-13 MURA.However,as the photon energy increases,the gap becomes almost negligible.