In order to improve the trajectory tracking precision and reduce the synchronization error of a 6-DOF lightweight robot, nonlinear proportion-deviation （N-PD） cross-coupling synchronization control strategy based on...In order to improve the trajectory tracking precision and reduce the synchronization error of a 6-DOF lightweight robot, nonlinear proportion-deviation （N-PD） cross-coupling synchronization control strategy based on adjacent coupling error analysis is presented. The mathematical models of the robot, including kinematic model, dynamic model and spline trajectory planing, are established and verified. Since it is difficult to describe the real-time contour error of the robot for complex trajectory, the adjacent coupling error is analyzed to solve the problem. Combined with nonlinear control and coupling performance of the robot, N-PD cross-coupling synchronization controller is designed and validated by simulation analysis. A servo control experimental system which mainly consists of laser tracking system, the robot mechanical system and EtherCAT based servo control system is constructed. The synchronization error is significantly decreased and the maximum trajectory error is reduced from 0.33 mm to 0.1 mm. The effectiveness of the control algorithm is validated by the experimental results, thus the control strategy can improve the robot＇s trajectory tracking precision significantly.展开更多
The performance-based passive control analysis of the Maxwell dampers between one 10-story and one 6-story adjacent RC frames is conducted in this work.Not only the optimal parameters but also the optimal arrangements...The performance-based passive control analysis of the Maxwell dampers between one 10-story and one 6-story adjacent RC frames is conducted in this work.Not only the optimal parameters but also the optimal arrangements of the Maxwell dampers are proposed based on the optimal target of making the total exceeding probability of the adjacent structures to be minimal.The applicability of the analytical expressions of the Maxwell damper damping parameters under different seismic performance targets are firstly examined and then the preferable damping parameters of the Maxwell dampers are proposed through the extensive parametric studies.Furthermore,the optimal arranging positions and optimal arranging numbers of the Maxwell dampers between the adjacent buildings are derived based on a large number of seismic fragility analyses,as well.The general arranging laws of the Maxwell dampers between the adjacent buildings are generated based on the discussion of the theoretical method through the simplified plane model.The optimal parameters and optimal arrangement of the Maxwell dampers presented make both the adjacent structures have preferable controlled effects under each seismic performance target which can satisfy the requirements of multi-performance seismic resistance of the modern seismic codes.展开更多
Synchronous reluctance motors(SynRM)are widely employed in industrial applications due to their high robustness,low cost,and absence of permanent magnets.In recent years,significant research efforts have focused on im...Synchronous reluctance motors(SynRM)are widely employed in industrial applications due to their high robustness,low cost,and absence of permanent magnets.In recent years,significant research efforts have focused on improving the controllability and efficiency of SynRM.Accurate rotor position information is essential for the controller to generate appropriate current and voltage references corresponding to the desired speed and load torque.Shaft-mounted position sensors are generally undesirable because of their high cost,sensitivity to harsh operating conditions,maintenance requirements,and reduced reliability in environments characterized by high vibration.Consequently,sensorless control techniques that estimate rotor position using measured stator currents and voltages have attracted increasing attention.However,magnetic saturation,parameter nonlinearities,and cross-coupling effects significantly degrade position estimation accuracy and may compromise the stability of sensorless SynRM drives.In this paper,a nonlinear SynRM model is developed using finite element analysis(FEA)to accurately capture magnetic saturation and cross-coupling effects,thereby providing a precise representation of the machine’s electromagnetic behavior under varying load and flux conditions.A series of magnetostatic FEA simulations is performed.To reduce computational complexity,only one motor pole is analyzed by applying anti-periodic boundary conditions along the domain sides and enforcing a zero magnetic vector potential on the external stator boundary.Nonlinear iron material properties are modeled using the appropriate B-H curve.The simulations are carried out by imposing d-and q-axis current components and computing the corresponding flux linkages and electromagnetic torque.Based on these results,both apparent and incremental inductances are extracted and incorporated into the control algorithm.An advanced fictitious flux linkage method combined with a phase-locked loop(PLL)is employed for accurate rotor position estimation.Simulation results confirm that the proposed sensorless control strategy ensures stable operation and high position estimation accuracy over the entire speed range.展开更多
Dynamic response analysis of damper connected adjacent multi-story structures with uncertain parameters is carried out.A formula of the multi degree of freedom(MDOF) for the structure-damper system with stochastic par...Dynamic response analysis of damper connected adjacent multi-story structures with uncertain parameters is carried out.A formula of the multi degree of freedom(MDOF) for the structure-damper system with stochastic parameters is derived.The uncertainties of mass and stiffness are taken into consideration firstly.The ground acceleration is represented by Kanai-Tajimi filtered non-stationary process.The mean square random responses of structural displacement and story drift are chosen as the optimization objective.The variations of mean square responses of top floor displacements and bottom story drifts in neighboring structures with the damper stiffness and damping coefficient are analyzed in detail.Through the parametric study,the acquiring optimum parameters of damper are regarded as numerical results.Then,a reducing order model of the MDOF system for adjacent structures with mean parameters is presented.The explicit expressions for determining optimal parameters of Kelvin model-defined damper which is used to connect adjacent single degree of freedom(SDOF) structures subjected to a white-noise excitation are employed to achieve the appropriate damper parameters,which are called theory results.Through a comparative study,it can be found that the theory values of damper parameters are consistent with the results based on extensive parametric studies.The analytical results can be obtained by using the first natural frequencies and the total mass of the adjacent deterministic structures with mean parameters.The analytical formulas can be used to find appropriate parameters of damper between adjacent structures for engineering applications.The performance of damper is investigated on the basis of mitigations of mean square random responses of inter-story drifts,displacements and accelerations in adjacent structures.The numerical results demonstrate the robustness of coupled building control strategies.展开更多
In conventional cross-coupled controller design,the method usually ignored the inherent characteristic of time-vary-ing parameters and model uncertainties in system.In this paper,a cross-coupled controller(CCC)using a...In conventional cross-coupled controller design,the method usually ignored the inherent characteristic of time-vary-ing parameters and model uncertainties in system.In this paper,a cross-coupled controller(CCC)using an H~∞control scheme has been proposed to reduce the contouring error for an X-Y table.Furthermore,the proposed CCC design,which is a typical Multi-Input Multi-Output(MIMO)system with linear time varying(LTV)characteristics,has been verified as being internally stable.The simulations are carried on Matlab simulink to verify the proposed method,and the results showed that the proposed method can reduce the contouring error significantly compared with the conventional one.展开更多
A new control strategy named adjacent coupling error strategy is proposed to multi-motor drive system. The adjacent coupling error control scheme is developed considering the tracking speed error in one motor and the ...A new control strategy named adjacent coupling error strategy is proposed to multi-motor drive system. The adjacent coupling error control scheme is developed considering the tracking speed error in one motor and the synchronous error among adjacent motors simultaneously. In the strategy, due to non-linear effects of the two mentioned errors to the motion control of motor i, an adaptive fuzzy logic controller is designed to decide the control variable of the motor drive system. The multi-motor drive system is modeled and simulated by SIMULINK. The simulated researches show that the proposed strategy improves the synchronization, stabilization, and convergence of the multi-motor system.展开更多
In order to improve the seismic performance of adjacent buildings,two types of tuned inerter damper(TID)damping systems for adjacent buildings are proposed,which are composed of springs,inerter devices and dampers in ...In order to improve the seismic performance of adjacent buildings,two types of tuned inerter damper(TID)damping systems for adjacent buildings are proposed,which are composed of springs,inerter devices and dampers in serial or in parallel.The dynamic equations of TID adjacent building damping systems were derived,and the H2 norm criterion was used to optimize and adjust them,so that the system had the optimum damping performance under white noise random excitation.Taking TID frequency ratio and damping ratio as optimization parameters,the optimum analytical solutions of the displacement frequency response of the undamped structure under white noise excitation were obtained.The results showed that compared with the classic TMD,TID could obtain a better damping effect in the adjacent buildings.Comparing the TIDs composed of serial or parallel,it was found that the parallel TIDs had more significant advantages in controlling the peak displacement frequency response,while the H2 norm of the displacement frequency response of the damping system under the coupling of serial TID was smaller.Taking the adjacent building composed of two ten-story frame structures as an example,the displacement and energy collection time history analysis of the adjacent building coupled with the optimum design parameter TIDs were carried out.It was found that TID had a better damping effect in the full-time range compared with the classic TMD.This paper also studied the potential power of TID in adjacent buildings,which can be converted into available power resources during earthquakes.展开更多
A control area network （CAN） based multi-motor synchronized motion control system with an advanced synchronized control strategy is proposed. The strategy is to incorporate the adjacent cross-coupling control strate...A control area network （CAN） based multi-motor synchronized motion control system with an advanced synchronized control strategy is proposed. The strategy is to incorporate the adjacent cross-coupling control strategy into the sliding mode control architecture. As illustrated by the four-induction-motor-based experimental results, the multi-motor synchronized motion control system, via the CAN bus, has been successfully implemented. With the employment of the advanced synchronized motion control strategy, the synchronization performance can be significantly improved.展开更多
The synchronous tracking control problem of a hydraulic parallel manipulator with six degrees of freedom (DOF) is complicated since the inclusion of hydraulic elements increases the order of the system.To solve this p...The synchronous tracking control problem of a hydraulic parallel manipulator with six degrees of freedom (DOF) is complicated since the inclusion of hydraulic elements increases the order of the system.To solve this problem,cascade control method with an inner/outer-loop control structure is used,which masks the hydraulic dynamics with the inner-loop so that the designed controller takes into account of both the mechanical dynamics and the hydraulic dynamics of the manipulator.Furthermore,a cross-coupling control approach is introduced to the synchronous tracking control of the manipulator.The position synchronization error is developed by considering motion synchronization between each actuator joint and its adjacent ones based on the synchronous goal.Then,with the feedback of both position error and synchronization error,the tracking is proven to guarantee that both the position errors and synchronization errors asymptotically converge to zero.Moreover,the effectiveness of the proposed approach is verified by the experimental results performed with a 6-DOF hydraulic parallel manipulator.展开更多
A model free intelligent muhivariable fuzzy controller （MFC） designed for modulating the vapor compression cycles in a residential inverter-driven air conditioning is proposed. The novel controller combines a tradit...A model free intelligent muhivariable fuzzy controller （MFC） designed for modulating the vapor compression cycles in a residential inverter-driven air conditioning is proposed. The novel controller combines a traditional fuzzy controller （TFC） and an additional coupling fuzzy controller, the coupling fuzzy controller is introduced to compensate for the unknown cross-coupling effects of this muhivariable system. In order to evaluate the control performance of the MFC, it is digitally implemented in terms of regulating the desired evaporating temperature and superheat. The experimental results show the effectiveness of the MFC for improvement of system performance and energy efficiency.展开更多
A novel acceleration tracking controller is proposed in this paper, for a Spinning Glide Guided Projectile(SGGP) subject to cross-coupling dynamics, external disturbances, and parametric uncertainties. The cross-coupl...A novel acceleration tracking controller is proposed in this paper, for a Spinning Glide Guided Projectile(SGGP) subject to cross-coupling dynamics, external disturbances, and parametric uncertainties. The cross-coupled dynamics for the SGGP are formulated with mismatched and matched uncertainties, and then divided into acceleration and angular rate subsystems via the hierarchical principle. By exploiting the structural property of the SGGP, model-assisted Extended State Observers(ESOs) are designed to estimate online the lumped disturbances in the acceleration and angular rate dynamics. To achieve a rapid response and a strong robustness, integral sliding mode control laws and sigmoid-function-based tracking differentiators are integrated into the ESO-based Trajectory Linearization Control(TLC) framework. It is proven that the acceleration tracking controller can guarantee the ultimate boundedness of the signals in the closed-loop system and make the tracking errors arbitrarily small. The superiority and effectiveness of the proposed control scheme in its decoupling ability, accurate acceleration tracking performance and antidisturbance capability are validated through comparisons and extensive simulations.展开更多
The proper phase difference of traffic signals for adjacent intersections could decrease the time of operational delay. Some theorems show how to minimize the total average delay time for vehicle operating at adjacent...The proper phase difference of traffic signals for adjacent intersections could decrease the time of operational delay. Some theorems show how to minimize the total average delay time for vehicle operating at adjacent intersections under given conditions. If the distance and signal cycles of adjacent intersections satisfy with specific conditions, the total average delay time would achieve zero. If the signal cycles of adjacent intersections and the phase difference of them are co-prime numbers, the total average delay time would be a constant. In general, if signal cycles of adjacent intersections and the phase difference of them are reducible numbers, the minimum total average delay time would be solved by the given algorithm. Numerical experiments have verified the rationality of these theorems.展开更多
It is difficult for the traditional pan-tilt-zoom(PTZ)system driven by electromagnetic motor to meet the growing demand for video surveillance system.The key challenge is high positioning accuracy,high dynamic perform...It is difficult for the traditional pan-tilt-zoom(PTZ)system driven by electromagnetic motor to meet the growing demand for video surveillance system.The key challenge is high positioning accuracy,high dynamic performance and miniaturization of the PTZ system.Here a PTZ system driven by two degree-of-freedom obeliskshaped ultrasonic motor with single stator is presented,and its intelligent control algorithm is studied.The structure and driving mechanism of the presented PTZ system are analyzed by both simulation and experiment.To solve the complex nonlinear factors,e.g.time-variation,dead zone,the fuzzy PID control algorithm and the variable gain cross-coupled control strategy are combined to improve the control performance.The results show that the proposed algorithm has faster response,higher precision than traditional control algorithm,and it also has a good robustness to prevent the effect of interference.展开更多
基金Project(2015AA043003)supported by National High-technology Research and Development Program of ChinaProject(GY2016ZB0068)supported by Application Technology Research and Development Program of Heilongjiang Province,ChinaProject(SKLR201301A03)supported by Self-planned Task of State Key Laboratory of Robotics and System(Harbin Institute of Technology),China
文摘In order to improve the trajectory tracking precision and reduce the synchronization error of a 6-DOF lightweight robot, nonlinear proportion-deviation （N-PD） cross-coupling synchronization control strategy based on adjacent coupling error analysis is presented. The mathematical models of the robot, including kinematic model, dynamic model and spline trajectory planing, are established and verified. Since it is difficult to describe the real-time contour error of the robot for complex trajectory, the adjacent coupling error is analyzed to solve the problem. Combined with nonlinear control and coupling performance of the robot, N-PD cross-coupling synchronization controller is designed and validated by simulation analysis. A servo control experimental system which mainly consists of laser tracking system, the robot mechanical system and EtherCAT based servo control system is constructed. The synchronization error is significantly decreased and the maximum trajectory error is reduced from 0.33 mm to 0.1 mm. The effectiveness of the control algorithm is validated by the experimental results, thus the control strategy can improve the robot＇s trajectory tracking precision significantly.
基金Projects(51408443,51178203)supported by the National Natural Science Foundation of ChinaProject(K201511)supported by the Science Foundation of Wuhan Institute of Technology,China
文摘The performance-based passive control analysis of the Maxwell dampers between one 10-story and one 6-story adjacent RC frames is conducted in this work.Not only the optimal parameters but also the optimal arrangements of the Maxwell dampers are proposed based on the optimal target of making the total exceeding probability of the adjacent structures to be minimal.The applicability of the analytical expressions of the Maxwell damper damping parameters under different seismic performance targets are firstly examined and then the preferable damping parameters of the Maxwell dampers are proposed through the extensive parametric studies.Furthermore,the optimal arranging positions and optimal arranging numbers of the Maxwell dampers between the adjacent buildings are derived based on a large number of seismic fragility analyses,as well.The general arranging laws of the Maxwell dampers between the adjacent buildings are generated based on the discussion of the theoretical method through the simplified plane model.The optimal parameters and optimal arrangement of the Maxwell dampers presented make both the adjacent structures have preferable controlled effects under each seismic performance target which can satisfy the requirements of multi-performance seismic resistance of the modern seismic codes.
文摘Synchronous reluctance motors(SynRM)are widely employed in industrial applications due to their high robustness,low cost,and absence of permanent magnets.In recent years,significant research efforts have focused on improving the controllability and efficiency of SynRM.Accurate rotor position information is essential for the controller to generate appropriate current and voltage references corresponding to the desired speed and load torque.Shaft-mounted position sensors are generally undesirable because of their high cost,sensitivity to harsh operating conditions,maintenance requirements,and reduced reliability in environments characterized by high vibration.Consequently,sensorless control techniques that estimate rotor position using measured stator currents and voltages have attracted increasing attention.However,magnetic saturation,parameter nonlinearities,and cross-coupling effects significantly degrade position estimation accuracy and may compromise the stability of sensorless SynRM drives.In this paper,a nonlinear SynRM model is developed using finite element analysis(FEA)to accurately capture magnetic saturation and cross-coupling effects,thereby providing a precise representation of the machine’s electromagnetic behavior under varying load and flux conditions.A series of magnetostatic FEA simulations is performed.To reduce computational complexity,only one motor pole is analyzed by applying anti-periodic boundary conditions along the domain sides and enforcing a zero magnetic vector potential on the external stator boundary.Nonlinear iron material properties are modeled using the appropriate B-H curve.The simulations are carried out by imposing d-and q-axis current components and computing the corresponding flux linkages and electromagnetic torque.Based on these results,both apparent and incremental inductances are extracted and incorporated into the control algorithm.An advanced fictitious flux linkage method combined with a phase-locked loop(PLL)is employed for accurate rotor position estimation.Simulation results confirm that the proposed sensorless control strategy ensures stable operation and high position estimation accuracy over the entire speed range.
基金supported by the National Natural Science Foundation of China (No. 50778077)the National Science Foundation for Distinguished Young Scholars of China (No. 50925828)
文摘Dynamic response analysis of damper connected adjacent multi-story structures with uncertain parameters is carried out.A formula of the multi degree of freedom(MDOF) for the structure-damper system with stochastic parameters is derived.The uncertainties of mass and stiffness are taken into consideration firstly.The ground acceleration is represented by Kanai-Tajimi filtered non-stationary process.The mean square random responses of structural displacement and story drift are chosen as the optimization objective.The variations of mean square responses of top floor displacements and bottom story drifts in neighboring structures with the damper stiffness and damping coefficient are analyzed in detail.Through the parametric study,the acquiring optimum parameters of damper are regarded as numerical results.Then,a reducing order model of the MDOF system for adjacent structures with mean parameters is presented.The explicit expressions for determining optimal parameters of Kelvin model-defined damper which is used to connect adjacent single degree of freedom(SDOF) structures subjected to a white-noise excitation are employed to achieve the appropriate damper parameters,which are called theory results.Through a comparative study,it can be found that the theory values of damper parameters are consistent with the results based on extensive parametric studies.The analytical results can be obtained by using the first natural frequencies and the total mass of the adjacent deterministic structures with mean parameters.The analytical formulas can be used to find appropriate parameters of damper between adjacent structures for engineering applications.The performance of damper is investigated on the basis of mitigations of mean square random responses of inter-story drifts,displacements and accelerations in adjacent structures.The numerical results demonstrate the robustness of coupled building control strategies.
文摘In conventional cross-coupled controller design,the method usually ignored the inherent characteristic of time-vary-ing parameters and model uncertainties in system.In this paper,a cross-coupled controller(CCC)using an H~∞control scheme has been proposed to reduce the contouring error for an X-Y table.Furthermore,the proposed CCC design,which is a typical Multi-Input Multi-Output(MIMO)system with linear time varying(LTV)characteristics,has been verified as being internally stable.The simulations are carried on Matlab simulink to verify the proposed method,and the results showed that the proposed method can reduce the contouring error significantly compared with the conventional one.
基金National Natural Science Foundation of China (No.60774023)
文摘A new control strategy named adjacent coupling error strategy is proposed to multi-motor drive system. The adjacent coupling error control scheme is developed considering the tracking speed error in one motor and the synchronous error among adjacent motors simultaneously. In the strategy, due to non-linear effects of the two mentioned errors to the motion control of motor i, an adaptive fuzzy logic controller is designed to decide the control variable of the motor drive system. The multi-motor drive system is modeled and simulated by SIMULINK. The simulated researches show that the proposed strategy improves the synchronization, stabilization, and convergence of the multi-motor system.
基金This research was funded by the Natural Science Research Project of Higher Education Institutions in Anhui Province(Grant No.2022AH040045)the Anhui Provincial Natural Science Foundation(Grant No.2008085QE245)the Project of Science and Technology Plan of Department of Housing and Urban-Rural Development of Anhui Province(Grant No.2021-YF22).
文摘In order to improve the seismic performance of adjacent buildings,two types of tuned inerter damper(TID)damping systems for adjacent buildings are proposed,which are composed of springs,inerter devices and dampers in serial or in parallel.The dynamic equations of TID adjacent building damping systems were derived,and the H2 norm criterion was used to optimize and adjust them,so that the system had the optimum damping performance under white noise random excitation.Taking TID frequency ratio and damping ratio as optimization parameters,the optimum analytical solutions of the displacement frequency response of the undamped structure under white noise excitation were obtained.The results showed that compared with the classic TMD,TID could obtain a better damping effect in the adjacent buildings.Comparing the TIDs composed of serial or parallel,it was found that the parallel TIDs had more significant advantages in controlling the peak displacement frequency response,while the H2 norm of the displacement frequency response of the damping system under the coupling of serial TID was smaller.Taking the adjacent building composed of two ten-story frame structures as an example,the displacement and energy collection time history analysis of the adjacent building coupled with the optimum design parameter TIDs were carried out.It was found that TID had a better damping effect in the full-time range compared with the classic TMD.This paper also studied the potential power of TID in adjacent buildings,which can be converted into available power resources during earthquakes.
基金supported by National Natural Science Foundation of China (No. 69774011)
文摘A control area network （CAN） based multi-motor synchronized motion control system with an advanced synchronized control strategy is proposed. The strategy is to incorporate the adjacent cross-coupling control strategy into the sliding mode control architecture. As illustrated by the four-induction-motor-based experimental results, the multi-motor synchronized motion control system, via the CAN bus, has been successfully implemented. With the employment of the advanced synchronized motion control strategy, the synchronization performance can be significantly improved.
基金Project(50375139) supported by the National Natural Science Foundation of ChinaProject(NCET-04-0545) supported by the New Century Excellent Talent Plan of the Ministry of Education of China
文摘The synchronous tracking control problem of a hydraulic parallel manipulator with six degrees of freedom (DOF) is complicated since the inclusion of hydraulic elements increases the order of the system.To solve this problem,cascade control method with an inner/outer-loop control structure is used,which masks the hydraulic dynamics with the inner-loop so that the designed controller takes into account of both the mechanical dynamics and the hydraulic dynamics of the manipulator.Furthermore,a cross-coupling control approach is introduced to the synchronous tracking control of the manipulator.The position synchronization error is developed by considering motion synchronization between each actuator joint and its adjacent ones based on the synchronous goal.Then,with the feedback of both position error and synchronization error,the tracking is proven to guarantee that both the position errors and synchronization errors asymptotically converge to zero.Moreover,the effectiveness of the proposed approach is verified by the experimental results performed with a 6-DOF hydraulic parallel manipulator.
基金This work is supported by the National High Technology Research and Development Program of China (863 Programs, GrantNo. 2007AA05Z224)Knowledge Innovation Project of Chinese Academy of Sciences(Grant No.KGCX2-YW-345)Zhejiang Scientific and Technological Project(Grant No.2009C3113004)
文摘A model free intelligent muhivariable fuzzy controller （MFC） designed for modulating the vapor compression cycles in a residential inverter-driven air conditioning is proposed. The novel controller combines a traditional fuzzy controller （TFC） and an additional coupling fuzzy controller, the coupling fuzzy controller is introduced to compensate for the unknown cross-coupling effects of this muhivariable system. In order to evaluate the control performance of the MFC, it is digitally implemented in terms of regulating the desired evaporating temperature and superheat. The experimental results show the effectiveness of the MFC for improvement of system performance and energy efficiency.
基金supported by the Fundamental Research Funds for the Central University(No.30919011401)。
文摘A novel acceleration tracking controller is proposed in this paper, for a Spinning Glide Guided Projectile(SGGP) subject to cross-coupling dynamics, external disturbances, and parametric uncertainties. The cross-coupled dynamics for the SGGP are formulated with mismatched and matched uncertainties, and then divided into acceleration and angular rate subsystems via the hierarchical principle. By exploiting the structural property of the SGGP, model-assisted Extended State Observers(ESOs) are designed to estimate online the lumped disturbances in the acceleration and angular rate dynamics. To achieve a rapid response and a strong robustness, integral sliding mode control laws and sigmoid-function-based tracking differentiators are integrated into the ESO-based Trajectory Linearization Control(TLC) framework. It is proven that the acceleration tracking controller can guarantee the ultimate boundedness of the signals in the closed-loop system and make the tracking errors arbitrarily small. The superiority and effectiveness of the proposed control scheme in its decoupling ability, accurate acceleration tracking performance and antidisturbance capability are validated through comparisons and extensive simulations.
文摘The proper phase difference of traffic signals for adjacent intersections could decrease the time of operational delay. Some theorems show how to minimize the total average delay time for vehicle operating at adjacent intersections under given conditions. If the distance and signal cycles of adjacent intersections satisfy with specific conditions, the total average delay time would achieve zero. If the signal cycles of adjacent intersections and the phase difference of them are co-prime numbers, the total average delay time would be a constant. In general, if signal cycles of adjacent intersections and the phase difference of them are reducible numbers, the minimum total average delay time would be solved by the given algorithm. Numerical experiments have verified the rationality of these theorems.
基金supported by the National Natural Science Foundation of China (No.51205193)the Research Fund for Doctoral Program of the Ministry of Education(No.20123218120037)
文摘It is difficult for the traditional pan-tilt-zoom(PTZ)system driven by electromagnetic motor to meet the growing demand for video surveillance system.The key challenge is high positioning accuracy,high dynamic performance and miniaturization of the PTZ system.Here a PTZ system driven by two degree-of-freedom obeliskshaped ultrasonic motor with single stator is presented,and its intelligent control algorithm is studied.The structure and driving mechanism of the presented PTZ system are analyzed by both simulation and experiment.To solve the complex nonlinear factors,e.g.time-variation,dead zone,the fuzzy PID control algorithm and the variable gain cross-coupled control strategy are combined to improve the control performance.The results show that the proposed algorithm has faster response,higher precision than traditional control algorithm,and it also has a good robustness to prevent the effect of interference.
