Joint power control has advantages of multi-user detection and power control; and it can combat the multi-access interference and the near-far problem. A novel adaptive joint power control algorithm with channel estim...Joint power control has advantages of multi-user detection and power control; and it can combat the multi-access interference and the near-far problem. A novel adaptive joint power control algorithm with channel estimation in a CDMA cellular system was designed. Simulation results show that the algorithm can control the power not only quickly but also precisely with a time change. The method is useful for increasing system capacity.展开更多
To address the problems of torque limit and controller saturation in the control of robot arm joint,an anti-windup control strategy is proposed for a humanoid robot arm,which is based on the integral state prediction ...To address the problems of torque limit and controller saturation in the control of robot arm joint,an anti-windup control strategy is proposed for a humanoid robot arm,which is based on the integral state prediction under the direct torque control system of brushless DC motor. First,the arm joint of the humanoid robot is modelled. Then the speed controller model and the influence of the initial value of the integral element on the system are analyzed. On the basis of the traditional antiwindup controller,an integral state estimator is set up. Under the condition of different load torques and the given speed,the integral steady-state value is estimated. Therefore the accumulation of the speed error terminates when the integrator reaches saturation. Then the predicted integral steady-state value is used as the initial value of the regulator to enter the linear region to make the system achieve the purpose of anti-windup. The simulation results demonstrate that the control strategy for the humanoid robot arm joint based on integral state prediction can play the role of anti-windup and suppress the overshoot of the system effectively. The system has a good dynamic performance.展开更多
Modal analysis is a fundamental and important task for modeling and control of the flexible manipulator. However, almost all of the traditional modal analysis methods view the flexible manipulator as a pure mechanical...Modal analysis is a fundamental and important task for modeling and control of the flexible manipulator. However, almost all of the traditional modal analysis methods view the flexible manipulator as a pure mechanical structure and neglect feedback action of joint controller. In order to study the effects of joint controller on the modal analysis of rotational flexible manipulator, a closed-loop analytical modal analysis method is proposed. Firstly, two exact boundary constraints, namely servo feedback constraint and bending moment constraint, are derived to solve the vibration partial differential equation. It is found that the stiffness and damping gains of joint controller are both included in the boundary conditions, which lead to an unconventional secular term. Secondly, analytical algorithm based on Ritz approach is developed by using Laplace transform and complex modal approach to obtain the natural frequencies and mode shapes. And then, the numerical simulations are performed and the computational results show that joint controller has pronounced influence on the modal parameters： joint controller stiffness reduces the natural frequency, while joint controller damping makes the shape phase non-zero. Furthermore, the validity of the presented conclusion is confirmed through experimental studies. These findings are expected to improve the performance of dynamics simulation systems and model-based controllers.展开更多
A parallel manipulator joint driven by three pneumatic muscles and its posture control strategy are presented. Based on geometric constraints and dynamics, a system model is developed through which some influences on ...A parallel manipulator joint driven by three pneumatic muscles and its posture control strategy are presented. Based on geometric constraints and dynamics, a system model is developed through which some influences on dynamic response and open-loop gain are analyzed including the supply pressure, the initial pressure and the volume of pneumatic muscle. A sliding-mode controller with a nonlinear switching function is applied to control posture, which adopts the combination of a main method that separates control of each muscle and an auxiliary method that postures error evaluation of multiple muscles, especially adopting the segmented and intelligent adjustments of sliding-mode parameters to fit different expected postures and initial states. Experimental results show that this control strategy not only amounts to the steady-state error of 0. 1° without overshoot, but also achieves good trajectory tracking.展开更多
Controlled blasting techniques are used to control overbreak and to aid in the stability of the remaining rock formation. Presplitting is one of the most common methods which is used in many open pit mining and surfac...Controlled blasting techniques are used to control overbreak and to aid in the stability of the remaining rock formation. Presplitting is one of the most common methods which is used in many open pit mining and surface blast design. The purpose of presplitting is to form a fracture plane across which the radial cracks from the production blast cannot travel. The purpose of this study is to investigate of effect of presplitting on the generation of a smooth wall in continuum and jointed rock mass. The 2D distinct element code was used to simulate the presplitting in a rock slope. The blast load history as a function of time was applied to the inner wall of each blasthole. Important parameters that were considered in the analysis were stress tensor and fracturing pattern. The blast loading magnitude and blasthole spacing and jointing pattern were found to be very significant in the final results.展开更多
In the realm of quadruped robot locomotion,compliance control is imperative to handle impacts when negotiating unstructured terrains.At the same time,kinematic tracking accuracy should be guaranteed during locomotion....In the realm of quadruped robot locomotion,compliance control is imperative to handle impacts when negotiating unstructured terrains.At the same time,kinematic tracking accuracy should be guaranteed during locomotion.To meet both demands,ajoint space compliance controller is designed,so that compliance can be achieved in stance phase while position tracking performance can be guaranteed in swing phase.Unlike operational space compliance control,the joint space compliance control method is easy to implement and does not depend on robot dynamics.As for each joint actuator,high performance force control is of great importance for compliance design.Therefore,a nonlinear PI controller based on feedback linearization is proposed for the hydraulic actuator force control.Besides,an outer position loop（compliance loop）is closed for each joint.Experiments are carried out to verify the force controller and compliance of the hydraulic actuator.The robot leg compliance is assessed by a virtual prototyping simulation.展开更多
A set of new current sensing device is used to realize joint torque control based on current measurement in a precision assembly robot's third joint. The output torque's model of the joint's brushless DC m...A set of new current sensing device is used to realize joint torque control based on current measurement in a precision assembly robot's third joint. The output torque's model of the joint's brushless DC motor is founded. Disturbance factors and the compensated effect of the torque's closed loop based on current measurement are analyzed. Related simulations and experiments show that the system has good current tracking and anti-disturbances performance, which improve the force control performance of the robot in assembly.展开更多
The three important historical development stages of China from"standing up","getting rich"to"becoming strong"were analyzed deeply.Regional coordinated development policies and strategies...The three important historical development stages of China from"standing up","getting rich"to"becoming strong"were analyzed deeply.Regional coordinated development policies and strategies have also gone through the"enlightenment stage","development stage"and"mature stage".On this basis,the problems of the coordination of China s regional coordinated development and joint prevention and control for environmental protection in the new era,as well as suggestions for the next step were further analyzed.展开更多
The Oligocene Yacheng Fm contains the most important source rocks that have been confirmed by exploratory wells in the Qiongdongnan Basin.The efficiency of these source rocks is the key to the breakthrough in natural ...The Oligocene Yacheng Fm contains the most important source rocks that have been confirmed by exploratory wells in the Qiongdongnan Basin.The efficiency of these source rocks is the key to the breakthrough in natural gas exploration in the study area.This paper analyzes the hydrocarbon potential of each sag in this basin from the perspective of control of both source rocks and geothermal heat.Two types of source rocks occur in the Yacheng Fm,namely mudstone of transitional facies and mudstone of neritic facies.Both of them are dominated by a kerogen of type-III,followed by type-II.Their organic matter abundances are controlled by the amount of continental clastic input.The mudstone of transitional facies is commonly higher in organic matter abundance,while that of neritic facies is lower.The coal-measure source rocks of transitional facies were mainly formed in such environments as delta plains,coastal plains and barrier tidal flat-marshes.Due to the control of Cenozoic lithosphere extension and influence of neotectonism,the geothermal gradient,terrestrial heat flow value(HFV)and level of thermal evolution are generally high in deep water.The hot setting not only determines the predominance of gas generation in the deep-water sags,but can promote the shallow-buried source rocks in shallow water into oil window to generate oil.In addition to promoting the hydrocarbon generation of source rocks,the high geothermal and high heat flow value can also speed up the cracking of residual hydrocarbons,thus enhancing hydrocarbon generation efficiency and capacity.According to the theory of joint control of source quality and geothermal heat on hydrocarbon generation,we comprehensively evaluate and rank the exploration potentials of major sags in the Qiongdongnan Basin.These sags are divided into 3 types,of which type-I sags including Yanan,Lingshui,Baodao,Ledong and Huaguang are the highest in hydrocarbon exploration potential.展开更多
Technology standard alliance, as vectors of research, development and circulation for technology standard, has already become an important transformation form from laboratory standard to fact standard for all countrie...Technology standard alliance, as vectors of research, development and circulation for technology standard, has already become an important transformation form from laboratory standard to fact standard for all countries. However, during the process of forming the technology standard alliance, it is a focus for members in the alliance to take control over others. How to construct a scientific and reasonable decision model of control over technology standard alliance is closely related to each enterprise member＇s interest. Under the condition that the risk is neutral, the paper explored necessary and sufficient conditions of knowledge sharing and the most endeavor among enterprise members through constructing a decision model of control over technology standard alliance, and put forward that the joint control model was the best decision model for constructing the technology standard alliance.展开更多
Joint prevention and control is a social organization model dealing with the governance of public health and security incidents.The governance models should have the features of multiple subjects co-governing and dist...Joint prevention and control is a social organization model dealing with the governance of public health and security incidents.The governance models should have the features of multiple subjects co-governing and distributed cooperating.Their purposes are to solve and improve the governance efficiency of dealing with public health and security incidents at the executive level.However,there are still many deficiencies in the current data governance and collaborative governance of joint prevention and control systems,which are mainly reflected in incomplete data collection,unimpeded data sharing,inflexible collaborative cooperation,and inadequate collaborative supervision.Therefore,a new innovative governance model is urgently needed.Blockchain technology is suitable for implementing multiparty data sharing and cooperation,and at the same time,it supports penetrating supervision and management.This paper studies the blockchain model for joint governance of public health and security incidents.It focuses on the multiagent collaborative prevention and control governance model,which provides a new opportunity for model innovation in data governance and in cooperative governance.展开更多
Joints are widely used in many kinds of engineering structures, which often leads to the structures to exhibit local nonlinearities, and moreover, they are difficult to model because the complexity of configuration an...Joints are widely used in many kinds of engineering structures, which often leads to the structures to exhibit local nonlinearities, and moreover, they are difficult to model because the complexity of configuration and operating mode. Therefore, parameter identification technique is usually used to model the joints and estimate the model parameters. A novel parameter identification method of nonlinear joints inside a structure is introduced in this paper, by expressing the force transmitted by the joint as a function of its mechanical state and assuming that the other part of the structure is known. In general, the force transmitted by the joints inside a structure and their mechanical state are difficult to measure. To overcome this difficulty, the algorithm of stochastic optimal control is used to identify the force transmitted by the joints and their mechanical state. After that, parameters of the joints can be identified by least squares parameter estimation method. Numerical simulation examples are also given to validate the effectiveness of the proposed method.展开更多
An innovation is conducted on a K190πK rail auto welding machine because of its poor stability in quality of welding joints. A new control system based on a programmable controller is designed to replace the old o...An innovation is conducted on a K190πK rail auto welding machine because of its poor stability in quality of welding joints. A new control system based on a programmable controller is designed to replace the old one. The new control system is of higher accuracy in controlling sequence and good ability in anti disturbance, and is convenient to operate. The comparison tests are carried out. The experimental results show that the quality of welded joints is greatly increased by the improved welding mechine.展开更多
文摘Joint power control has advantages of multi-user detection and power control; and it can combat the multi-access interference and the near-far problem. A novel adaptive joint power control algorithm with channel estimation in a CDMA cellular system was designed. Simulation results show that the algorithm can control the power not only quickly but also precisely with a time change. The method is useful for increasing system capacity.
基金Supported by the National Natural Science Foundation of China(61175090,61703249)Shandong Provincial Natural Science Foundation,China(ZR2017MF045)
文摘To address the problems of torque limit and controller saturation in the control of robot arm joint,an anti-windup control strategy is proposed for a humanoid robot arm,which is based on the integral state prediction under the direct torque control system of brushless DC motor. First,the arm joint of the humanoid robot is modelled. Then the speed controller model and the influence of the initial value of the integral element on the system are analyzed. On the basis of the traditional antiwindup controller,an integral state estimator is set up. Under the condition of different load torques and the given speed,the integral steady-state value is estimated. Therefore the accumulation of the speed error terminates when the integrator reaches saturation. Then the predicted integral steady-state value is used as the initial value of the regulator to enter the linear region to make the system achieve the purpose of anti-windup. The simulation results demonstrate that the control strategy for the humanoid robot arm joint based on integral state prediction can play the role of anti-windup and suppress the overshoot of the system effectively. The system has a good dynamic performance.
基金Supported by National Natural Science Foundation of China(Grant No.51305039)Specialized Research Fund for the Doctoral Program of Higher Education,China(Grant No.20110005120004)+1 种基金Fundamental Research Funds for the Central Universities,China(Grant No.2014PTB-00-01)National Basic Research Program of China(973 Program,Grant No.2013CB733000)
文摘Modal analysis is a fundamental and important task for modeling and control of the flexible manipulator. However, almost all of the traditional modal analysis methods view the flexible manipulator as a pure mechanical structure and neglect feedback action of joint controller. In order to study the effects of joint controller on the modal analysis of rotational flexible manipulator, a closed-loop analytical modal analysis method is proposed. Firstly, two exact boundary constraints, namely servo feedback constraint and bending moment constraint, are derived to solve the vibration partial differential equation. It is found that the stiffness and damping gains of joint controller are both included in the boundary conditions, which lead to an unconventional secular term. Secondly, analytical algorithm based on Ritz approach is developed by using Laplace transform and complex modal approach to obtain the natural frequencies and mode shapes. And then, the numerical simulations are performed and the computational results show that joint controller has pronounced influence on the modal parameters： joint controller stiffness reduces the natural frequency, while joint controller damping makes the shape phase non-zero. Furthermore, the validity of the presented conclusion is confirmed through experimental studies. These findings are expected to improve the performance of dynamics simulation systems and model-based controllers.
基金This project is supported by International Cooperation with Festo.
文摘A parallel manipulator joint driven by three pneumatic muscles and its posture control strategy are presented. Based on geometric constraints and dynamics, a system model is developed through which some influences on dynamic response and open-loop gain are analyzed including the supply pressure, the initial pressure and the volume of pneumatic muscle. A sliding-mode controller with a nonlinear switching function is applied to control posture, which adopts the combination of a main method that separates control of each muscle and an auxiliary method that postures error evaluation of multiple muscles, especially adopting the segmented and intelligent adjustments of sliding-mode parameters to fit different expected postures and initial states. Experimental results show that this control strategy not only amounts to the steady-state error of 0. 1° without overshoot, but also achieves good trajectory tracking.
文摘Controlled blasting techniques are used to control overbreak and to aid in the stability of the remaining rock formation. Presplitting is one of the most common methods which is used in many open pit mining and surface blast design. The purpose of presplitting is to form a fracture plane across which the radial cracks from the production blast cannot travel. The purpose of this study is to investigate of effect of presplitting on the generation of a smooth wall in continuum and jointed rock mass. The 2D distinct element code was used to simulate the presplitting in a rock slope. The blast load history as a function of time was applied to the inner wall of each blasthole. Important parameters that were considered in the analysis were stress tensor and fracturing pattern. The blast loading magnitude and blasthole spacing and jointing pattern were found to be very significant in the final results.
基金Supported by the National High Technology Research and Development Program of China(863 Program)(2011AA041002)
文摘In the realm of quadruped robot locomotion,compliance control is imperative to handle impacts when negotiating unstructured terrains.At the same time,kinematic tracking accuracy should be guaranteed during locomotion.To meet both demands,ajoint space compliance controller is designed,so that compliance can be achieved in stance phase while position tracking performance can be guaranteed in swing phase.Unlike operational space compliance control,the joint space compliance control method is easy to implement and does not depend on robot dynamics.As for each joint actuator,high performance force control is of great importance for compliance design.Therefore,a nonlinear PI controller based on feedback linearization is proposed for the hydraulic actuator force control.Besides,an outer position loop（compliance loop）is closed for each joint.Experiments are carried out to verify the force controller and compliance of the hydraulic actuator.The robot leg compliance is assessed by a virtual prototyping simulation.
基金Supported by the National 863 Scheme of China No.863-512-03-02
文摘A set of new current sensing device is used to realize joint torque control based on current measurement in a precision assembly robot's third joint. The output torque's model of the joint's brushless DC motor is founded. Disturbance factors and the compensated effect of the torque's closed loop based on current measurement are analyzed. Related simulations and experiments show that the system has good current tracking and anti-disturbances performance, which improve the force control performance of the robot in assembly.
基金Supported by National Key Research and Development Plan(2016YFC0208102)Special Project for Transformation of Scientific and Technological Achievements in Jiangsu Province(BA2020001)Special Project for Prevention and Control of Air Pollution from Fixed Sources of Ministry of Ecology and Environment,China in 2020(2020A060).
文摘The three important historical development stages of China from"standing up","getting rich"to"becoming strong"were analyzed deeply.Regional coordinated development policies and strategies have also gone through the"enlightenment stage","development stage"and"mature stage".On this basis,the problems of the coordination of China s regional coordinated development and joint prevention and control for environmental protection in the new era,as well as suggestions for the next step were further analyzed.
基金National Key Basic Research and Development Plan(973 plans)“Basic research on oil and gas formation and distribution in deep water basins in South China Sea”(No.2009CB219400)Special and Significant Project of National Science and Technology“Key technology of marine oil and gas exploration in deep water area”(No.2008ZX05025 and 2011ZX05025)Investigation and Evaluation Project of National Strategic Petroleum Resource Provinces of the Ministry of Land and Resources(No.XQ-2004-05 and XQ-2007-05).
文摘The Oligocene Yacheng Fm contains the most important source rocks that have been confirmed by exploratory wells in the Qiongdongnan Basin.The efficiency of these source rocks is the key to the breakthrough in natural gas exploration in the study area.This paper analyzes the hydrocarbon potential of each sag in this basin from the perspective of control of both source rocks and geothermal heat.Two types of source rocks occur in the Yacheng Fm,namely mudstone of transitional facies and mudstone of neritic facies.Both of them are dominated by a kerogen of type-III,followed by type-II.Their organic matter abundances are controlled by the amount of continental clastic input.The mudstone of transitional facies is commonly higher in organic matter abundance,while that of neritic facies is lower.The coal-measure source rocks of transitional facies were mainly formed in such environments as delta plains,coastal plains and barrier tidal flat-marshes.Due to the control of Cenozoic lithosphere extension and influence of neotectonism,the geothermal gradient,terrestrial heat flow value(HFV)and level of thermal evolution are generally high in deep water.The hot setting not only determines the predominance of gas generation in the deep-water sags,but can promote the shallow-buried source rocks in shallow water into oil window to generate oil.In addition to promoting the hydrocarbon generation of source rocks,the high geothermal and high heat flow value can also speed up the cracking of residual hydrocarbons,thus enhancing hydrocarbon generation efficiency and capacity.According to the theory of joint control of source quality and geothermal heat on hydrocarbon generation,we comprehensively evaluate and rank the exploration potentials of major sags in the Qiongdongnan Basin.These sags are divided into 3 types,of which type-I sags including Yanan,Lingshui,Baodao,Ledong and Huaguang are the highest in hydrocarbon exploration potential.
文摘Technology standard alliance, as vectors of research, development and circulation for technology standard, has already become an important transformation form from laboratory standard to fact standard for all countries. However, during the process of forming the technology standard alliance, it is a focus for members in the alliance to take control over others. How to construct a scientific and reasonable decision model of control over technology standard alliance is closely related to each enterprise member＇s interest. Under the condition that the risk is neutral, the paper explored necessary and sufficient conditions of knowledge sharing and the most endeavor among enterprise members through constructing a decision model of control over technology standard alliance, and put forward that the joint control model was the best decision model for constructing the technology standard alliance.
基金“Shandong Social Science Planning and Research Project”/“Shandong Academy of Social Sciences Innovation Project”(20BCXJ01)Shandong Provincial Major Technology Innovation Projection under Grant 2018CXGC0703.
文摘Joint prevention and control is a social organization model dealing with the governance of public health and security incidents.The governance models should have the features of multiple subjects co-governing and distributed cooperating.Their purposes are to solve and improve the governance efficiency of dealing with public health and security incidents at the executive level.However,there are still many deficiencies in the current data governance and collaborative governance of joint prevention and control systems,which are mainly reflected in incomplete data collection,unimpeded data sharing,inflexible collaborative cooperation,and inadequate collaborative supervision.Therefore,a new innovative governance model is urgently needed.Blockchain technology is suitable for implementing multiparty data sharing and cooperation,and at the same time,it supports penetrating supervision and management.This paper studies the blockchain model for joint governance of public health and security incidents.It focuses on the multiagent collaborative prevention and control governance model,which provides a new opportunity for model innovation in data governance and in cooperative governance.
文摘Joints are widely used in many kinds of engineering structures, which often leads to the structures to exhibit local nonlinearities, and moreover, they are difficult to model because the complexity of configuration and operating mode. Therefore, parameter identification technique is usually used to model the joints and estimate the model parameters. A novel parameter identification method of nonlinear joints inside a structure is introduced in this paper, by expressing the force transmitted by the joint as a function of its mechanical state and assuming that the other part of the structure is known. In general, the force transmitted by the joints inside a structure and their mechanical state are difficult to measure. To overcome this difficulty, the algorithm of stochastic optimal control is used to identify the force transmitted by the joints and their mechanical state. After that, parameters of the joints can be identified by least squares parameter estimation method. Numerical simulation examples are also given to validate the effectiveness of the proposed method.
文摘An innovation is conducted on a K190πK rail auto welding machine because of its poor stability in quality of welding joints. A new control system based on a programmable controller is designed to replace the old one. The new control system is of higher accuracy in controlling sequence and good ability in anti disturbance, and is convenient to operate. The comparison tests are carried out. The experimental results show that the quality of welded joints is greatly increased by the improved welding mechine.
