An improved OPCL method is developed and applied to both small swing and giant rotation synchronization of a two-link mechanism. Transition processes of the two kinds of synchronization are discussed. Comparisons of d...An improved OPCL method is developed and applied to both small swing and giant rotation synchronization of a two-link mechanism. Transition processes of the two kinds of synchronization are discussed. Comparisons of different motion characteristics of the two-link synchronization and the effects of different control parameters on synchronous processes are investigated with numerical simulations.展开更多
Bistatic/multistatic radar has great potential advantages over its monostatic counterpart. However, the separation of a transmitter and a receiver leads to difficulties in locating the target position accurately and g...Bistatic/multistatic radar has great potential advantages over its monostatic counterpart. However, the separation of a transmitter and a receiver leads to difficulties in locating the target position accurately and guaranteeing space-timefrequency synchronization of the transmitter and the receiver.The error model of space-time-frequency synchronization in a motion platform of bistatic/multistatic radar is studied. The relationship between the space synchronization error and the transmitter platform position, receiver platform position, moving state, and beam pointing error, is analyzed. The effect of space synchronization error on target echo power is studied. The target scattering characteristics are restructured by many separate scattering centers of the target in high frequency regions. Based on the scattering centers model of the radar target, this radar target echo model and the simulation method are discussed. The algorithm of bistatic/multistatic radar target echo accurately reflects the scattering characteristics of the radar target, pulse modulation speciality of radar transmitting signals, and spacetime-frequency synchronization error characteristics between the transmitter station and the receiver station. The simulation of bistatic radar is completed in computer, and the results of the simulation validate the feasibility of the method.展开更多
The impulsive synchronization problem of two identical chaotic ratchets is investigated in this paper. We demonstrate that the impulsive method to control directed transport is applicable when there are multiple co-ex...The impulsive synchronization problem of two identical chaotic ratchets is investigated in this paper. We demonstrate that the impulsive method to control directed transport is applicable when there are multiple co-existing attractors in phase space transporting particles in different directions. Numerical simulations are carried out to illustrate the effectiveness of the proposed method.展开更多
A mirror milling system(MMS)comprises two face-to-face five-axis machine tools,one for the cutting spindle and the other for the support tool.Since it is essential to maintain the cutter and support coaxial during the...A mirror milling system(MMS)comprises two face-to-face five-axis machine tools,one for the cutting spindle and the other for the support tool.Since it is essential to maintain the cutter and support coaxial during the cutting process,synchronous motion accuracy is the key index of the MMS.This paper proposed a novel method for measuring and estimating the synchronous motion accuracy of the dual five-axis machine tools.The method simultaneously detects errors in the tool center point(TCP)and tool axis direction(TAD)during synchronous motion.To implement the suggested method,a measurement device,with five high-precision displacement sensors was developed.A kinematic model was then developed to estimate the synchronous motion accuracy from the displacement sensor output.The screw theory was used to obtain the analytical expression of the inverse kinematic model,and the synchronous motion error was compensated and adjusted based on the inverse kinematic model of the dual five-axis machine tools.TCP and TAD quasi-static errors,such as geometric and backlash errors,were first compensated.By adjusting the servo parameters,the dynamic TCP and TAD errors,such as gain mismatch and reversal spike,were also reduced.The proposed method and device were tested in a large MMS,and the measured quasi-static and dynamic errors were all reduced when the compensation and adjustment method was used.Monte Carlo simulations were also used to estimate the uncertainty of the proposed scheme.展开更多
We investigate motion synchronization of dual-cylinder pneumatic servo systems and develop an adaptive robust synchronization controller. The proposed controller incorporates the cross-coupling technology into the int...We investigate motion synchronization of dual-cylinder pneumatic servo systems and develop an adaptive robust synchronization controller. The proposed controller incorporates the cross-coupling technology into the integrated direct/indirect adaptive robust control(DIARC) architecture by feeding back the coupled position errors, which are formed by the trajectory tracking errors of two cylinders and the synchronization error between them. The controller employs an online recursive least squares estimation algorithm to obtain accurate estimates of model parameters for reducing the extent of parametric uncertainties, and uses a robust control law to attenuate the effects of parameter estimation errors, unmodeled dynamics, and disturbances. Therefore, asymptotic convergence to zero of both trajectory tracking and synchronization errors can be guaranteed. Experimental results verify the effectiveness of the proposed controller.展开更多
This paper presents an integrated fuzzy controller design approach to synchronize a dis- similar redundant actuation system of a hydraulic actuator (HA) and an electro-hydrostatic actu- ator (EHA) with system unce...This paper presents an integrated fuzzy controller design approach to synchronize a dis- similar redundant actuation system of a hydraulic actuator (HA) and an electro-hydrostatic actu- ator (EHA) with system uncertainties and disturbances. The motion synchronous control system consists of a trajectory generator, an individual position controller for each actuator, and a fuzzy force tracking controller (FFTC) for both actuators. The trajectory generator provides the desired motion dynamics and designing parameters of the trajectory which are taken according to the dynamic characteristics of the EHA. The position controller consists of a feed-forward controller and a fuzzy position tracking controller (FPTC) and acts as a decoupled controller, improving posi- tion tracking performance with the help of the feed-forward controller and the FPTC. The FFTC acts as a coupled controller and takes into account the inherent coupling effect. The simulation results show that the proposed controller not only eliminates initial force fighting by synchronizing the two actuators, but also improves disturbance rejection performance.展开更多
This paper presents an efficient synchronization control scheme for a high-accuracy synchronous mo- tion system. In particular, an optimal PID controller for individual motion axis is first developed to guarantee sati...This paper presents an efficient synchronization control scheme for a high-accuracy synchronous mo- tion system. In particular, an optimal PID controller for individual motion axis is first developed to guarantee satisfactory tracking performance according to traditional controller tuning strategy. Then, an additional synchronous controller is introduced to generate cross-coupling control action, so that synchronous position error across axes due to system manu- facturing tolerance or disturbance could be suppressed. Experimental results on a positioning system equipped with two permanent-magnet linear motors demonstrate that the synchronization performance with the proposed control scheme could be enhanced.展开更多
Aiming at decreasing the component complexity and cost of flower transplanting machine,an integrated transplanting method for picking and planting flower seedlings was proposed,and a hybrid-driven five-bar parallel me...Aiming at decreasing the component complexity and cost of flower transplanting machine,an integrated transplanting method for picking and planting flower seedlings was proposed,and a hybrid-driven five-bar parallel mechanism was designed.A“beak-shaped”trajectory was designed for integrated transplanting requirements,and meantime,either the posture requirements of transplanting claw were determined.Based on the transplanting trajectory of the mechanism,a corresponding mathematical model for solving the link parameters was established,and then the five-bar mechanism was divided into two bar groups,optimization was conducted in two steps based on genetic algorithm and NSGA-II algorithm.Consequently,the optimal solution of the hybrid-driven five-bar parallel mechanism for flower seedling transplanting was obtained.Compared with similar designs,the trajectory displacement of the proposed mechanism is larger in the condition of smaller link size,which indicates that the mechanism can effectively decrease the machine size.The real-time controllable motor angular acceleration fluctuation is smaller and the commutation times are less,which has the advantage of reducing the difficulty of the mechanism control system.Subsequently,the correctness of the design method is verified by kinematics simulation.Finally,the synchronous linkage motion control methods of the two motors were designed,a transplanting experiment of the prototype was carried out,the picking success rate had reached 90%-93.4%and transplanting success rate was 80.5%-86.9%during experiment,which showed that the integrated operation of picking and planting flower seedlings can be realized by the proposed mechanism.展开更多
基金supported by the Key Project of Science and Technology Research of Ministry of Educationof China (No. 108037)the National Natural Science Foundation of China (No. 10402008 and50535010)
文摘An improved OPCL method is developed and applied to both small swing and giant rotation synchronization of a two-link mechanism. Transition processes of the two kinds of synchronization are discussed. Comparisons of different motion characteristics of the two-link synchronization and the effects of different control parameters on synchronous processes are investigated with numerical simulations.
基金supported by the National Natural Science Foundation of China(61271327)
文摘Bistatic/multistatic radar has great potential advantages over its monostatic counterpart. However, the separation of a transmitter and a receiver leads to difficulties in locating the target position accurately and guaranteeing space-timefrequency synchronization of the transmitter and the receiver.The error model of space-time-frequency synchronization in a motion platform of bistatic/multistatic radar is studied. The relationship between the space synchronization error and the transmitter platform position, receiver platform position, moving state, and beam pointing error, is analyzed. The effect of space synchronization error on target echo power is studied. The target scattering characteristics are restructured by many separate scattering centers of the target in high frequency regions. Based on the scattering centers model of the radar target, this radar target echo model and the simulation method are discussed. The algorithm of bistatic/multistatic radar target echo accurately reflects the scattering characteristics of the radar target, pulse modulation speciality of radar transmitting signals, and spacetime-frequency synchronization error characteristics between the transmitter station and the receiver station. The simulation of bistatic radar is completed in computer, and the results of the simulation validate the feasibility of the method.
基金supported by the National Natural Science Foundation of China (Grant No. 10901073)the Program for Innovative Research Team of Jiangnan University
文摘The impulsive synchronization problem of two identical chaotic ratchets is investigated in this paper. We demonstrate that the impulsive method to control directed transport is applicable when there are multiple co-existing attractors in phase space transporting particles in different directions. Numerical simulations are carried out to illustrate the effectiveness of the proposed method.
基金supported by the National Natural Science Foundation of China(Grant No.51875357)the State Key Program of National Natural Science Foundation of China(Grant No.U21B2081)the National Defense Science and Technology Excellence Youth Foundation(Grant No.2020-JCJQ-ZQ-079)。
文摘A mirror milling system(MMS)comprises two face-to-face five-axis machine tools,one for the cutting spindle and the other for the support tool.Since it is essential to maintain the cutter and support coaxial during the cutting process,synchronous motion accuracy is the key index of the MMS.This paper proposed a novel method for measuring and estimating the synchronous motion accuracy of the dual five-axis machine tools.The method simultaneously detects errors in the tool center point(TCP)and tool axis direction(TAD)during synchronous motion.To implement the suggested method,a measurement device,with five high-precision displacement sensors was developed.A kinematic model was then developed to estimate the synchronous motion accuracy from the displacement sensor output.The screw theory was used to obtain the analytical expression of the inverse kinematic model,and the synchronous motion error was compensated and adjusted based on the inverse kinematic model of the dual five-axis machine tools.TCP and TAD quasi-static errors,such as geometric and backlash errors,were first compensated.By adjusting the servo parameters,the dynamic TCP and TAD errors,such as gain mismatch and reversal spike,were also reduced.The proposed method and device were tested in a large MMS,and the measured quasi-static and dynamic errors were all reduced when the compensation and adjustment method was used.Monte Carlo simulations were also used to estimate the uncertainty of the proposed scheme.
基金supported by the Fundamental Research Funds for the Central Universities,China(No.2014QNA40)the Natural Science Foundation of Jiangsu Province,China(No.BK20140188)
文摘We investigate motion synchronization of dual-cylinder pneumatic servo systems and develop an adaptive robust synchronization controller. The proposed controller incorporates the cross-coupling technology into the integrated direct/indirect adaptive robust control(DIARC) architecture by feeding back the coupled position errors, which are formed by the trajectory tracking errors of two cylinders and the synchronization error between them. The controller employs an online recursive least squares estimation algorithm to obtain accurate estimates of model parameters for reducing the extent of parametric uncertainties, and uses a robust control law to attenuate the effects of parameter estimation errors, unmodeled dynamics, and disturbances. Therefore, asymptotic convergence to zero of both trajectory tracking and synchronization errors can be guaranteed. Experimental results verify the effectiveness of the proposed controller.
基金supported by the National Basic Research Program of China(973 Program)(No.2014CB046402)the National Natural Science Foundation of China(Nos.51575019,51305011)the 111 Program of China
文摘This paper presents an integrated fuzzy controller design approach to synchronize a dis- similar redundant actuation system of a hydraulic actuator (HA) and an electro-hydrostatic actu- ator (EHA) with system uncertainties and disturbances. The motion synchronous control system consists of a trajectory generator, an individual position controller for each actuator, and a fuzzy force tracking controller (FFTC) for both actuators. The trajectory generator provides the desired motion dynamics and designing parameters of the trajectory which are taken according to the dynamic characteristics of the EHA. The position controller consists of a feed-forward controller and a fuzzy position tracking controller (FPTC) and acts as a decoupled controller, improving posi- tion tracking performance with the help of the feed-forward controller and the FPTC. The FFTC acts as a coupled controller and takes into account the inherent coupling effect. The simulation results show that the proposed controller not only eliminates initial force fighting by synchronizing the two actuators, but also improves disturbance rejection performance.
文摘This paper presents an efficient synchronization control scheme for a high-accuracy synchronous mo- tion system. In particular, an optimal PID controller for individual motion axis is first developed to guarantee satisfactory tracking performance according to traditional controller tuning strategy. Then, an additional synchronous controller is introduced to generate cross-coupling control action, so that synchronous position error across axes due to system manu- facturing tolerance or disturbance could be suppressed. Experimental results on a positioning system equipped with two permanent-magnet linear motors demonstrate that the synchronization performance with the proposed control scheme could be enhanced.
基金The research work was financially supported by the National Natural Science Foundation of China(Grant No.51775512,51975536)Key research projects of Zhejiang Province(Grant No.2018C02046)+2 种基金Project funded by China Postdoctoral Science FoundationBasic public welfare research projects of Zhejiang Province(Grant No.LGN19E050002,LGN20E050006)Basic Scientific Research Foundation of Zhejiang Sci-Tech University.
文摘Aiming at decreasing the component complexity and cost of flower transplanting machine,an integrated transplanting method for picking and planting flower seedlings was proposed,and a hybrid-driven five-bar parallel mechanism was designed.A“beak-shaped”trajectory was designed for integrated transplanting requirements,and meantime,either the posture requirements of transplanting claw were determined.Based on the transplanting trajectory of the mechanism,a corresponding mathematical model for solving the link parameters was established,and then the five-bar mechanism was divided into two bar groups,optimization was conducted in two steps based on genetic algorithm and NSGA-II algorithm.Consequently,the optimal solution of the hybrid-driven five-bar parallel mechanism for flower seedling transplanting was obtained.Compared with similar designs,the trajectory displacement of the proposed mechanism is larger in the condition of smaller link size,which indicates that the mechanism can effectively decrease the machine size.The real-time controllable motor angular acceleration fluctuation is smaller and the commutation times are less,which has the advantage of reducing the difficulty of the mechanism control system.Subsequently,the correctness of the design method is verified by kinematics simulation.Finally,the synchronous linkage motion control methods of the two motors were designed,a transplanting experiment of the prototype was carried out,the picking success rate had reached 90%-93.4%and transplanting success rate was 80.5%-86.9%during experiment,which showed that the integrated operation of picking and planting flower seedlings can be realized by the proposed mechanism.