Intelligent production is an important development direction in intelligent manufacturing,with intelligent factories playing a crucial role in promoting intelligent production.Flexible job shops,as the main form of in...Intelligent production is an important development direction in intelligent manufacturing,with intelligent factories playing a crucial role in promoting intelligent production.Flexible job shops,as the main form of intelligent factories,constantly face dynamic disturbances during the production process,including machine failures and urgent orders.This paper discusses the basic models and research methods of job shop scheduling,emphasizing the important role of dynamic job shop scheduling and its response schemes in future research.A multi-objective flexible job shop dynamic scheduling mathematical model is established,highlighting its complex and multi-constraint characteristics under different interferences.A classification discussion is conducted on the dynamic response methods and optimization objectives under machine failures,emergency orders,fuzzy completion times,and mixed dynamic events.The development process of traditional scheduling rules and intelligent methods in dynamic scheduling are also analyzed.Finally,based on the current development status of job shop scheduling and the requirements of intelligent manufacturing,the future development trends of dynamic scheduling in flexible job shops are proposed.展开更多
Based on the discussion of functions, components, control structure and network computing architecture of generic shop floor control (GSFC) in computer integrated manufacturing system (CIMS), the internal integrati...Based on the discussion of functions, components, control structure and network computing architecture of generic shop floor control (GSFC) in computer integrated manufacturing system (CIMS), the internal integration between components of GSFC and the external integration between GSFC and the other components of CIMS are studied. The integration models on the aspects of function, information, processing and interface are put forward. The integration models and the methods are implemented and applied in CIMS projects successfully.展开更多
A robot intelligent path planning system RIPPS is developed, which can be utilized for a robot off line programming tool. The system consists of three parts: geometric modeler, kinematic modeler and path planer. The...A robot intelligent path planning system RIPPS is developed, which can be utilized for a robot off line programming tool. The system consists of three parts: geometric modeler, kinematic modeler and path planer. The geometric modeler is used to construct the robot working environment cluttered with obstacles and the robot kinematic modeler to define robot manipulators by the input parameters. Giving robot start and the goal configurations, the path planer can produce a quasi optimal path. By transforming obstacles into the C space to form C obstacles, the path searching is performed in C space. The planning simulations are performed on a SGI workstation, the future research is to implement the planer on a commercial robot manipulators.展开更多
This paper deals with fuzzy intelligent position control of electro-hydraulic activated robotic excavator for the control of boom, arm and bucket axes. Intelligent control systems are required to overcome unde- sirabl...This paper deals with fuzzy intelligent position control of electro-hydraulic activated robotic excavator for the control of boom, arm and bucket axes. Intelligent control systems are required to overcome unde- sirable stick-slip motion, limit cycles and oscillations. Models of electro-hydraulic servo controlled front end loader excavators are highly nonlinear. The nonlinear model accounts for fluid flow rate of valve, pump hydraulics, and friction forces. The friction forces are modelled by Coulomb, viscous and Stribeck function. Interval Type-2 Fuzzy Logic Controller （IT2FLC） is used to study the time-domain position responses of axes in the presence of external applied load. It has the ability to control the position of each of the three axes with minimum actuator position errors. Models presented are accurate and study the dynamics of the actuator and load. To improve the transient behaviour of the robotic excavator, we elim- inated iitter of the bucket movement in the presence of nonlinearities.展开更多
In underground mining, machine design is predominantly dictated by mine conditions and individual customer desires. In partnership with Foresight Energy, J. H. Fletcher & Company was tasked to design and manufactu...In underground mining, machine design is predominantly dictated by mine conditions and individual customer desires. In partnership with Foresight Energy, J. H. Fletcher & Company was tasked to design and manufacture a new roof bolting machine with six independent drilling apparatus on board capable of drilling and bolting the roof and ribs with material handling. The objective was to produce a machine capable of drilling and installing six bolts simultaneously with a limited number of operators. The goal of the mine is to decrease the time to bolt a cut to improve the safety level of the current roof bolting method, improve efficiency and to improve the bottom line cost of entry development. The customer wanted four drills at the front of the machine dedicated to installing roof bolts and then another two drills behind them dedicated to rib bolts. This dictated the requirement of latched controls, which would allow the operator to start drilling one hole and then latch the controls to be able to move on to the next.The result of the design is a machine with a single platform and six independent masts with drillheads:four masts strictly for drilling and installing roof bolts on the front of the platform and two masts on the back of the platform for rib bolts. The controls at each operator's station include a latch control for drilling. The six-head roof bolter allows fewer operators to drill and install roof and rib bolts, which in turn lowers the miners' roof exposure per cut. This design reduces the operator's exposure from the inherent pinch points and rotary hazards once he has engaged the latch drilling. Therefore, the machine will help to decrease the time to bolt a cut, improving productivity while enhancing the ability to operate the machine safely.展开更多
To obtain the near optimal path for the mobile robots in the present of the obstacles, where the robots are subject to both the nonholonomic constraints and the bound to the curvature of the path, a simple planning i...To obtain the near optimal path for the mobile robots in the present of the obstacles, where the robots are subject to both the nonholonomic constraints and the bound to the curvature of the path, a simple planning is applied by the heuristic searching method in which Reeds and Shepp’s shortest paths are chosen as heuristic functions. It has performed well in simulation of mobile robots moving in a cluttered environment.展开更多
Group distance coding is suitable for secret communication covered by printed documents. However there is no effective method against it. The study found that the hiding method will make group distances of text lines ...Group distance coding is suitable for secret communication covered by printed documents. However there is no effective method against it. The study found that the hiding method will make group distances of text lines coverage on specified values, and make variances of group distances among N-Window text lines become small. Inspired by the discovery, the research brings out a Support Vector Machine （SVM） based steganalysis algorithm. To avoid the disturbance of large difference among words length from same line, the research only reserves samples whose occurrence-frequencies are ± 10dB of the maximum frequency. The results show that the correct rate of the SVM classifier is higher than 90%.展开更多
A mathematical model of electromechanical coupling system for a planar inertial vibrating machine is built by setting up dynamical equations of discrete systems with a matrix methodology proposed. The substance of the...A mathematical model of electromechanical coupling system for a planar inertial vibrating machine is built by setting up dynamical equations of discrete systems with a matrix methodology proposed. The substance of the transient behavior of the machine is unveiled by analyzing the results of the computer simulation to the model, and new methods are presented for diminishing the transient amplitude of the vibrating machine and improving the transient behavior. The reliable mathematical model is provided for intelligent control of the transient behavior of the equipment.展开更多
基金supported by the National Key Research and Development Program Project(No.2021YFB3301300).
文摘Intelligent production is an important development direction in intelligent manufacturing,with intelligent factories playing a crucial role in promoting intelligent production.Flexible job shops,as the main form of intelligent factories,constantly face dynamic disturbances during the production process,including machine failures and urgent orders.This paper discusses the basic models and research methods of job shop scheduling,emphasizing the important role of dynamic job shop scheduling and its response schemes in future research.A multi-objective flexible job shop dynamic scheduling mathematical model is established,highlighting its complex and multi-constraint characteristics under different interferences.A classification discussion is conducted on the dynamic response methods and optimization objectives under machine failures,emergency orders,fuzzy completion times,and mixed dynamic events.The development process of traditional scheduling rules and intelligent methods in dynamic scheduling are also analyzed.Finally,based on the current development status of job shop scheduling and the requirements of intelligent manufacturing,the future development trends of dynamic scheduling in flexible job shops are proposed.
文摘Based on the discussion of functions, components, control structure and network computing architecture of generic shop floor control (GSFC) in computer integrated manufacturing system (CIMS), the internal integration between components of GSFC and the external integration between GSFC and the other components of CIMS are studied. The integration models on the aspects of function, information, processing and interface are put forward. The integration models and the methods are implemented and applied in CIMS projects successfully.
文摘A robot intelligent path planning system RIPPS is developed, which can be utilized for a robot off line programming tool. The system consists of three parts: geometric modeler, kinematic modeler and path planer. The geometric modeler is used to construct the robot working environment cluttered with obstacles and the robot kinematic modeler to define robot manipulators by the input parameters. Giving robot start and the goal configurations, the path planer can produce a quasi optimal path. By transforming obstacles into the C space to form C obstacles, the path searching is performed in C space. The planning simulations are performed on a SGI workstation, the future research is to implement the planer on a commercial robot manipulators.
文摘This paper deals with fuzzy intelligent position control of electro-hydraulic activated robotic excavator for the control of boom, arm and bucket axes. Intelligent control systems are required to overcome unde- sirable stick-slip motion, limit cycles and oscillations. Models of electro-hydraulic servo controlled front end loader excavators are highly nonlinear. The nonlinear model accounts for fluid flow rate of valve, pump hydraulics, and friction forces. The friction forces are modelled by Coulomb, viscous and Stribeck function. Interval Type-2 Fuzzy Logic Controller （IT2FLC） is used to study the time-domain position responses of axes in the presence of external applied load. It has the ability to control the position of each of the three axes with minimum actuator position errors. Models presented are accurate and study the dynamics of the actuator and load. To improve the transient behaviour of the robotic excavator, we elim- inated iitter of the bucket movement in the presence of nonlinearities.
文摘In underground mining, machine design is predominantly dictated by mine conditions and individual customer desires. In partnership with Foresight Energy, J. H. Fletcher & Company was tasked to design and manufacture a new roof bolting machine with six independent drilling apparatus on board capable of drilling and bolting the roof and ribs with material handling. The objective was to produce a machine capable of drilling and installing six bolts simultaneously with a limited number of operators. The goal of the mine is to decrease the time to bolt a cut to improve the safety level of the current roof bolting method, improve efficiency and to improve the bottom line cost of entry development. The customer wanted four drills at the front of the machine dedicated to installing roof bolts and then another two drills behind them dedicated to rib bolts. This dictated the requirement of latched controls, which would allow the operator to start drilling one hole and then latch the controls to be able to move on to the next.The result of the design is a machine with a single platform and six independent masts with drillheads:four masts strictly for drilling and installing roof bolts on the front of the platform and two masts on the back of the platform for rib bolts. The controls at each operator's station include a latch control for drilling. The six-head roof bolter allows fewer operators to drill and install roof and rib bolts, which in turn lowers the miners' roof exposure per cut. This design reduces the operator's exposure from the inherent pinch points and rotary hazards once he has engaged the latch drilling. Therefore, the machine will help to decrease the time to bolt a cut, improving productivity while enhancing the ability to operate the machine safely.
文摘To obtain the near optimal path for the mobile robots in the present of the obstacles, where the robots are subject to both the nonholonomic constraints and the bound to the curvature of the path, a simple planning is applied by the heuristic searching method in which Reeds and Shepp’s shortest paths are chosen as heuristic functions. It has performed well in simulation of mobile robots moving in a cluttered environment.
基金the National Natural Science Foundation of China under Grant No.61170269,No.61170272,No.61202082,No.61003285,and the Fundamental Research Funds for the Central Universities under Grant No.BUPT2013RC0308,No.BUPT2013RC0311
文摘Group distance coding is suitable for secret communication covered by printed documents. However there is no effective method against it. The study found that the hiding method will make group distances of text lines coverage on specified values, and make variances of group distances among N-Window text lines become small. Inspired by the discovery, the research brings out a Support Vector Machine （SVM） based steganalysis algorithm. To avoid the disturbance of large difference among words length from same line, the research only reserves samples whose occurrence-frequencies are ± 10dB of the maximum frequency. The results show that the correct rate of the SVM classifier is higher than 90%.
文摘A mathematical model of electromechanical coupling system for a planar inertial vibrating machine is built by setting up dynamical equations of discrete systems with a matrix methodology proposed. The substance of the transient behavior of the machine is unveiled by analyzing the results of the computer simulation to the model, and new methods are presented for diminishing the transient amplitude of the vibrating machine and improving the transient behavior. The reliable mathematical model is provided for intelligent control of the transient behavior of the equipment.
