In order to improve the frequency response and anti-interference characteristics of the smart electromechanical actuator(EMA)system,and aiming at the force fighting problem when multiple actuators work synchronously,a...In order to improve the frequency response and anti-interference characteristics of the smart electromechanical actuator(EMA)system,and aiming at the force fighting problem when multiple actuators work synchronously,a multi input multi output(MIMO)position difference cross coupling control coordinated strategy based on double‑closed-loop load feedforward control is proposed and designed.In this strategy,the singular value method of return difference matrix is used to design the parameter range that meets the requirements of system stability margin,and the sensitivity function and the H_(∞)norm theory are used to design and determine the optimal solution in the obtained parameter stability region,so that the multi actuator system has excellent synchronization,stability and anti-interference.At the same time,the mathematical model of the integrated smart EMA system is established.According to the requirements of point-to-point control,the controller of double-loop control and load feedforward compensation is determined and designed to improve the frequency response and anti-interference ability of single actuator.Finally,the 270 V high-voltage smart EMA system experimental platform is built,and the frequency response,load feedforward compensation and coordinated control experiments are carried out to verify the correctness of the position difference cross coupling control strategy and the rationality of the parameter design,so that the system can reach the servo control indexes of bandwidth 6 Hz,the maximum output force 20000 N and the synchronization error≤0.1 mm,which effectively solves the problem of force fighting.展开更多
Due to low carrying capacity and short life of current ring reducer,we proposed a new planetary gearing with internal gear ring,which consisted of two stages.One was an involute planetary drive and the other was an N-...Due to low carrying capacity and short life of current ring reducer,we proposed a new planetary gearing with internal gear ring,which consisted of two stages.One was an involute planetary drive and the other was an N-type planetary drive with small teeth difference.The kinematic calculation was conducted based on the analysis of structural composition and working principle.Formulas of backlash calculation for the new planetary gearing were derived by using probabilistic theory and the analytical model was created at the same time.Then,main factors that affect the systematic backlash were introduced and the effects of manufacture error,misaligments and roller bearing parameters on the distribution of backlash were presented.The influence of gear backlash on systematic return difference was performed based on the backlash mathematic model proposed.The results show that the backlash is a little large,of which the backlash of bearing takes a greater part than two gearing stages.So we presented some practical methods to reduce the systematic backlash.展开更多
The transformation of Chengdu Tianfu New Area,a state-level new district,from the first site of constructing the“Park City”to the representative of the“Park City”,contains a unique path of“Chinese Style Governanc...The transformation of Chengdu Tianfu New Area,a state-level new district,from the first site of constructing the“Park City”to the representative of the“Park City”,contains a unique path of“Chinese Style Governance”.To expand the diverse paths of constructing megacities,the current research references the nudge theory of behavioral science,adopts the extended case method,and takes Chengdu Tianfu New Area as a typical case to summarize the“nudge”path of“Party City”construction.The study found that the government achieves the lock-in effect by the priming mechanism and uses the nudge strategy of improving environment and guiding public opinion,thereby helping the people make free choices.It realizes the framework effect by the salience mechanism and uses the strategies of highlighting key information and optimizing information delivery methods,which directly affects the behavior of the public.It achieves the commitment effect by the comparison mechanism,including the horizontal comparison and vertical comparison strategies,and gradually realizes the policy goals.It realizes the social norm effect by the imitation mechanism and uses the strategies of creating peer pressure and playing celebrity effect,which in turn influence people’s choices.With the help of the“nudging”mechanism,the construction of the park city has realized the interactive cycle of“government output-citizen feedback”and achieved the goal of“making great change through small actions”.As a new behavioral intervention tool,“nudging”provides an alternative explanation for the construction of the park city in Tianfu New Area and opens up new ideas for the construction of megacities.This study concludes that the construction of megacities can achieve the goal of“common return”through different ways and provides practical inspiration for future urban construction.展开更多
基金supported by the National Natural Science Foundation of China(No.52077100)the Aviation Science Foundation(No.201958052001)
文摘In order to improve the frequency response and anti-interference characteristics of the smart electromechanical actuator(EMA)system,and aiming at the force fighting problem when multiple actuators work synchronously,a multi input multi output(MIMO)position difference cross coupling control coordinated strategy based on double‑closed-loop load feedforward control is proposed and designed.In this strategy,the singular value method of return difference matrix is used to design the parameter range that meets the requirements of system stability margin,and the sensitivity function and the H_(∞)norm theory are used to design and determine the optimal solution in the obtained parameter stability region,so that the multi actuator system has excellent synchronization,stability and anti-interference.At the same time,the mathematical model of the integrated smart EMA system is established.According to the requirements of point-to-point control,the controller of double-loop control and load feedforward compensation is determined and designed to improve the frequency response and anti-interference ability of single actuator.Finally,the 270 V high-voltage smart EMA system experimental platform is built,and the frequency response,load feedforward compensation and coordinated control experiments are carried out to verify the correctness of the position difference cross coupling control strategy and the rationality of the parameter design,so that the system can reach the servo control indexes of bandwidth 6 Hz,the maximum output force 20000 N and the synchronization error≤0.1 mm,which effectively solves the problem of force fighting.
基金Funded by Key Technology R&D Program of Chongqing(No. 2008AC3087)Science & Technology Project of Chongqing Education Committee(No. KJ091414)
文摘Due to low carrying capacity and short life of current ring reducer,we proposed a new planetary gearing with internal gear ring,which consisted of two stages.One was an involute planetary drive and the other was an N-type planetary drive with small teeth difference.The kinematic calculation was conducted based on the analysis of structural composition and working principle.Formulas of backlash calculation for the new planetary gearing were derived by using probabilistic theory and the analytical model was created at the same time.Then,main factors that affect the systematic backlash were introduced and the effects of manufacture error,misaligments and roller bearing parameters on the distribution of backlash were presented.The influence of gear backlash on systematic return difference was performed based on the backlash mathematic model proposed.The results show that the backlash is a little large,of which the backlash of bearing takes a greater part than two gearing stages.So we presented some practical methods to reduce the systematic backlash.
基金supported by General Project of National Social Science Fund[Grant number.22BZZ077],Study on Efficiency Improvement Mechanism of Rural Relative Poverty Governance Driven by Big Data.
文摘The transformation of Chengdu Tianfu New Area,a state-level new district,from the first site of constructing the“Park City”to the representative of the“Park City”,contains a unique path of“Chinese Style Governance”.To expand the diverse paths of constructing megacities,the current research references the nudge theory of behavioral science,adopts the extended case method,and takes Chengdu Tianfu New Area as a typical case to summarize the“nudge”path of“Party City”construction.The study found that the government achieves the lock-in effect by the priming mechanism and uses the nudge strategy of improving environment and guiding public opinion,thereby helping the people make free choices.It realizes the framework effect by the salience mechanism and uses the strategies of highlighting key information and optimizing information delivery methods,which directly affects the behavior of the public.It achieves the commitment effect by the comparison mechanism,including the horizontal comparison and vertical comparison strategies,and gradually realizes the policy goals.It realizes the social norm effect by the imitation mechanism and uses the strategies of creating peer pressure and playing celebrity effect,which in turn influence people’s choices.With the help of the“nudging”mechanism,the construction of the park city has realized the interactive cycle of“government output-citizen feedback”and achieved the goal of“making great change through small actions”.As a new behavioral intervention tool,“nudging”provides an alternative explanation for the construction of the park city in Tianfu New Area and opens up new ideas for the construction of megacities.This study concludes that the construction of megacities can achieve the goal of“common return”through different ways and provides practical inspiration for future urban construction.
