Increase of elevator speed brings about amplified vibrations of high-speed elevator. In order to reduce the horizontal vibrations of high-speed elevator, a new type of hydraulic active guide roller system based on fuz...Increase of elevator speed brings about amplified vibrations of high-speed elevator. In order to reduce the horizontal vibrations of high-speed elevator, a new type of hydraulic active guide roller system based on fuzzy logic controller is developed. First the working principle of the hydraulic guide system is introduced, then the dynamic model of the horizontal vibrations for elevator cage with active guide roller system and the mathematical model of the hydraulic system are given. A fuzzy logic controller for the hydraulic system is designed to control the hydraulic actuator. To improve the control performance, preview compensation for the controller is provided. Finally, simulation and experiments are executed to verify the hydraulic active guide roller system and the control strategy. Both the simulation and experimental results indicate that the hydraulic active guide roller system can reduce the horizontal vibrations of the elevator effectively and has better effects than the passive one, and the fuzzy logic controller with preview compensation can give superior control performance.展开更多
An inside-cushion structure with sidestep and taper-shaped plungers is studied to address the problems of high impact and vibration in high-speed hydraulic cylinders.First,the three stages of cushion processes are dis...An inside-cushion structure with sidestep and taper-shaped plungers is studied to address the problems of high impact and vibration in high-speed hydraulic cylinders.First,the three stages of cushion processes are discussed according to the varying flow area as the piston moves.Then,to establish a precise mathematical model,the states of the flow field are estimated in terms of the Reynolds number.Accordingly,the simulation model parameterized against measured data is developed and verified by experiment.Last,the average velocity,peak cushion pressure,and terminal velocity are defined to evaluate cushion performance.According to these optimized objectives,the non-linear programming by quadratic Lagrange(NLPQL)algorithm is applied to optimize the structure parameters.The optimization results indicate that the peak cushion pressure is reduced by 28%and terminal velocity is reduced by 21%without reduction of average velocity.展开更多
The aerodynamic braking is a clean and non-adhesion braking, and can be used to provide extra braking force during high-speed emergency braking. The research of aerodynamic braking has attracted more and more attentio...The aerodynamic braking is a clean and non-adhesion braking, and can be used to provide extra braking force during high-speed emergency braking. The research of aerodynamic braking has attracted more and more attentions in recent years. However, most researchers in this field focus on aerodynamic effects and seldom on issues of position control of the aerodynamic braking board. The purpose of this paper is to explore position control optimization of the braking board in an aerodynamic braking prototype. The mathematical models of the hydraulic drive unit in the aerodynamic braking system are analyzed in detail, and the simulation models are established. Three control functions--constant, linear, and quadratic--are explored. Two kinds of criteria, including the position steady-state error and the acceleration of the piston rod, are used to evaluate system performance. Simulation results show that the position steady state-error is reduced from around 12-2 mm by applying a linear instead of a constant function, while the acceleration is reduced from 25,71-3.70 m/s2 with a quadratic control function. Use of the quadratic control function is shown to improve system performance. Experimental results obtained by measuring the position response of the piston rod on a test-bench also suggest a reduced position error and smooth movement of the piston rod. This implies that the acceleration is smaller when using the quadratic function, thus verifying the effectiveness of control schemes to improve to system performance. This paper proposes an effective and easily implemented control scheme that improves the position response of hydraulic cylinders during position control.展开更多
With the widespread application of the computer and microelectronic technology in the industry,digitization becomes the inevitable developing trend of the hydraulic technology.Digitization of the hydraulic components ...With the widespread application of the computer and microelectronic technology in the industry,digitization becomes the inevitable developing trend of the hydraulic technology.Digitization of the hydraulic components is critical in the digital hydraulic technology.High-speed on-of valves(HSVs)which convert a train of input pulses into the fast and accurate switching between the on and of states belong to widely used basic digital hydraulic elements.In some ways,the characteristics of the HSVs determine the performance of the digital hydraulic systems.This paper discusses the development of HSVs and their applications.First,the HSVs with innovative structures which is classifed into direct drive valves and pilot operated valves are discussed,with the emphasis on their performance.Then,an overview of HSVs with intelligent materials is presented with considering of the switching frequency and fow capacity.Finally,the applications of the HSVs are reviewed,including digital hydraulic components with the integration of the HSVs and digital hydraulic systems controlled by the HSVs.展开更多
文摘Increase of elevator speed brings about amplified vibrations of high-speed elevator. In order to reduce the horizontal vibrations of high-speed elevator, a new type of hydraulic active guide roller system based on fuzzy logic controller is developed. First the working principle of the hydraulic guide system is introduced, then the dynamic model of the horizontal vibrations for elevator cage with active guide roller system and the mathematical model of the hydraulic system are given. A fuzzy logic controller for the hydraulic system is designed to control the hydraulic actuator. To improve the control performance, preview compensation for the controller is provided. Finally, simulation and experiments are executed to verify the hydraulic active guide roller system and the control strategy. Both the simulation and experimental results indicate that the hydraulic active guide roller system can reduce the horizontal vibrations of the elevator effectively and has better effects than the passive one, and the fuzzy logic controller with preview compensation can give superior control performance.
基金National Natural Science Foundation of China(51705152)Jiangxi Provincial Natural Science Foundation(20161BAB206150+2 种基金20161BAB216133)Jiangxi Provincial Key R&D Program(20171BBG70040)Innovation Fund Designated for Graduate Students of Jiangxi Province(YC2018-S246)。
文摘An inside-cushion structure with sidestep and taper-shaped plungers is studied to address the problems of high impact and vibration in high-speed hydraulic cylinders.First,the three stages of cushion processes are discussed according to the varying flow area as the piston moves.Then,to establish a precise mathematical model,the states of the flow field are estimated in terms of the Reynolds number.Accordingly,the simulation model parameterized against measured data is developed and verified by experiment.Last,the average velocity,peak cushion pressure,and terminal velocity are defined to evaluate cushion performance.According to these optimized objectives,the non-linear programming by quadratic Lagrange(NLPQL)algorithm is applied to optimize the structure parameters.The optimization results indicate that the peak cushion pressure is reduced by 28%and terminal velocity is reduced by 21%without reduction of average velocity.
基金supported by National Natural Science Foundation of China(Grant No.61004077)Fundamental Research Funds for the Central Universities of China(Grant No.2860219022)Foundation of Traction Power State Key Laboratory of Southwest Jiaotong University,China(Grant No.TPL1308)
文摘The aerodynamic braking is a clean and non-adhesion braking, and can be used to provide extra braking force during high-speed emergency braking. The research of aerodynamic braking has attracted more and more attentions in recent years. However, most researchers in this field focus on aerodynamic effects and seldom on issues of position control of the aerodynamic braking board. The purpose of this paper is to explore position control optimization of the braking board in an aerodynamic braking prototype. The mathematical models of the hydraulic drive unit in the aerodynamic braking system are analyzed in detail, and the simulation models are established. Three control functions--constant, linear, and quadratic--are explored. Two kinds of criteria, including the position steady-state error and the acceleration of the piston rod, are used to evaluate system performance. Simulation results show that the position steady state-error is reduced from around 12-2 mm by applying a linear instead of a constant function, while the acceleration is reduced from 25,71-3.70 m/s2 with a quadratic control function. Use of the quadratic control function is shown to improve system performance. Experimental results obtained by measuring the position response of the piston rod on a test-bench also suggest a reduced position error and smooth movement of the piston rod. This implies that the acceleration is smaller when using the quadratic function, thus verifying the effectiveness of control schemes to improve to system performance. This paper proposes an effective and easily implemented control scheme that improves the position response of hydraulic cylinders during position control.
基金Supported by Key Technologies Research and Development Program of China(Grant No.2019YFB2004502)National Natural Science Foundation of China(Grant Nos.51805350,51775362)Postdoctoral Science Foundation of China(Grant No.2019M651073).
文摘With the widespread application of the computer and microelectronic technology in the industry,digitization becomes the inevitable developing trend of the hydraulic technology.Digitization of the hydraulic components is critical in the digital hydraulic technology.High-speed on-of valves(HSVs)which convert a train of input pulses into the fast and accurate switching between the on and of states belong to widely used basic digital hydraulic elements.In some ways,the characteristics of the HSVs determine the performance of the digital hydraulic systems.This paper discusses the development of HSVs and their applications.First,the HSVs with innovative structures which is classifed into direct drive valves and pilot operated valves are discussed,with the emphasis on their performance.Then,an overview of HSVs with intelligent materials is presented with considering of the switching frequency and fow capacity.Finally,the applications of the HSVs are reviewed,including digital hydraulic components with the integration of the HSVs and digital hydraulic systems controlled by the HSVs.
