The mechanical characteristics of the electro-hydraulic servo system in thecentrifuge field are analyzed. The hydraulic pressure law in the centrifuge field indicates theexistence of the centrifuge hydraulic pressure....The mechanical characteristics of the electro-hydraulic servo system in thecentrifuge field are analyzed. The hydraulic pressure law in the centrifuge field indicates theexistence of the centrifuge hydraulic pressure. The mechanical characteristics of the slide-valveand the dual nozzle flapper valve are studied, and it is found that the centrifuge field can notonly increase the driving force or moment of the function units, but also decrease the stability ofthe components. Finally by applying Gauss minimum constraint principle, the dynamic model of theelectro-hydraulic vibrator in the centrifuge field is established, and the mechanical restriction ofthe system is also presented. The study will be helpful for the realization of the combinedvibration and centrifuge test system.展开更多
Dynamic modeling of a parallel manipulator（PM） is an important issue. A complete PM system is actually composed of multiple physical domains. As PMs are widely used in various fields, the importance of modeling the ...Dynamic modeling of a parallel manipulator（PM） is an important issue. A complete PM system is actually composed of multiple physical domains. As PMs are widely used in various fields, the importance of modeling the global dynamic model of the PM system becomes increasingly prominent. Currently there lacks further research in global dynamic modeling. A unified modeling approach for the multi-energy domains PM system is proposed based on bond graph and a global dynamic model of the 3-UPS/S parallel stabilized platform involving mechanical and electrical-hydraulic elements is built. Firstly, the screw bond graph theory is improved based on the screw theory, the modular joint model is modeled and the normalized dynamic model of the mechanism is established. Secondly, combined with the electro-hydraulic servo system model built by traditional bond graph, the global dynamic model of the system is obtained, and then the motion, force and power of any element can be obtained directly. Lastly, the experiments and simulations of the driving forces, pressure and flow are performed, and the results show that, the theoretical calculation results of the driving forces are in accord with the experimental ones, and the pressure and flow of the first limb and the third limb are symmetry with each other. The results are reasonable and verify the correctness and effectiveness of the model and the method. The proposed dynamic modeling method provides a reference for modeling of other multi-energy domains system which contains complex PM.展开更多
针对液驱并联机构多维力加载系统非线性、时变和强耦合的系统特性,提出一种改进PID控制策略以提高系统输出精度。通过构建多维力加载系统动力学模型与液压动力元件模型,分析研究耦合力产生机理。将多维力加载时受系统自身结构影响的各...针对液驱并联机构多维力加载系统非线性、时变和强耦合的系统特性,提出一种改进PID控制策略以提高系统输出精度。通过构建多维力加载系统动力学模型与液压动力元件模型,分析研究耦合力产生机理。将多维力加载时受系统自身结构影响的各通道间耦合力与系统参数摄动等非线性因素视为干扰,采用模糊控制对PID参数进行实时调整,抑制系统非线性干扰以提高跟踪精度;考虑到传统经验法或专家知识库的模糊推理对PID控制参数调整不够精细,提出一种模糊PID与小脑模型神经网络(cerebellar model articulation controller,CMAC)并行的控制策略,利用其自适应能力与快速学习非线性函数能力对模糊PID控制过程进行学习和插补。研究结果表明:与PID控制器相比,CMAC-模糊PID控制器能够有效地解决液驱并联机构多维力加载系统复杂的跟踪问题。展开更多
This article, in order to precisely impose friction on aircraft and weapon actuation systems, presents a new friction loading method characteristic of ＂torque-zero velocity＂ switching control with an electro-hydraul...This article, in order to precisely impose friction on aircraft and weapon actuation systems, presents a new friction loading method characteristic of ＂torque-zero velocity＂ switching control with an electro-hydraulic load simulator. As the general Stribeck friction model has little related to static friction, it proposes a ＂torque-zero velocity＂ switcher, in which a zero-velocity controller is developed to load the static friction and a torque controller the kinetic friction. With the help of mathematical modeling, this article designs a ＂torque-zero velocity＂ switching controller and, correspondingly, provides a ＂dual-threshold judgment＂ algorithm. Simulation results indicate that the proposed method can be successfully used to carry out the static and kinetic friction simulation with an electro-hydraulic load simulator.展开更多
分析了电液伺服加载和板簧加载的工作原理与特点,搭建了试验平台,并分别对两种加载方式进行了试验研究.理论分析和试验结果均表明:以板簧加载为代表的机械加载,结构简单、成本较低,但加载精度低,灵活性差,仅能实现近似线性的简单加载规...分析了电液伺服加载和板簧加载的工作原理与特点,搭建了试验平台,并分别对两种加载方式进行了试验研究.理论分析和试验结果均表明:以板簧加载为代表的机械加载,结构简单、成本较低,但加载精度低,灵活性差,仅能实现近似线性的简单加载规律;电液伺服加载结构复杂,但能够实现多种加载规律,可模拟导弹舵机的真实负载状态.采用基于小脑模型神经网络(cerebellar model articulation controller,CMAC)的复合控制方法能够有效抑制多余力,提高加载精度.展开更多
基金This Project is supported by National Natural Science Foundation of China(No.19672047) and NSAF Foundation of China(No.10276032).
文摘The mechanical characteristics of the electro-hydraulic servo system in thecentrifuge field are analyzed. The hydraulic pressure law in the centrifuge field indicates theexistence of the centrifuge hydraulic pressure. The mechanical characteristics of the slide-valveand the dual nozzle flapper valve are studied, and it is found that the centrifuge field can notonly increase the driving force or moment of the function units, but also decrease the stability ofthe components. Finally by applying Gauss minimum constraint principle, the dynamic model of theelectro-hydraulic vibrator in the centrifuge field is established, and the mechanical restriction ofthe system is also presented. The study will be helpful for the realization of the combinedvibration and centrifuge test system.
基金Supported by National Natural Science Foundation of China(Grant Nos.51275438,51405421)Hebei Provincial Natural Science Foundation of China(Grant No.E2015203101)
文摘Dynamic modeling of a parallel manipulator（PM） is an important issue. A complete PM system is actually composed of multiple physical domains. As PMs are widely used in various fields, the importance of modeling the global dynamic model of the PM system becomes increasingly prominent. Currently there lacks further research in global dynamic modeling. A unified modeling approach for the multi-energy domains PM system is proposed based on bond graph and a global dynamic model of the 3-UPS/S parallel stabilized platform involving mechanical and electrical-hydraulic elements is built. Firstly, the screw bond graph theory is improved based on the screw theory, the modular joint model is modeled and the normalized dynamic model of the mechanism is established. Secondly, combined with the electro-hydraulic servo system model built by traditional bond graph, the global dynamic model of the system is obtained, and then the motion, force and power of any element can be obtained directly. Lastly, the experiments and simulations of the driving forces, pressure and flow are performed, and the results show that, the theoretical calculation results of the driving forces are in accord with the experimental ones, and the pressure and flow of the first limb and the third limb are symmetry with each other. The results are reasonable and verify the correctness and effectiveness of the model and the method. The proposed dynamic modeling method provides a reference for modeling of other multi-energy domains system which contains complex PM.
文摘针对液驱并联机构多维力加载系统非线性、时变和强耦合的系统特性,提出一种改进PID控制策略以提高系统输出精度。通过构建多维力加载系统动力学模型与液压动力元件模型,分析研究耦合力产生机理。将多维力加载时受系统自身结构影响的各通道间耦合力与系统参数摄动等非线性因素视为干扰,采用模糊控制对PID参数进行实时调整,抑制系统非线性干扰以提高跟踪精度;考虑到传统经验法或专家知识库的模糊推理对PID控制参数调整不够精细,提出一种模糊PID与小脑模型神经网络(cerebellar model articulation controller,CMAC)并行的控制策略,利用其自适应能力与快速学习非线性函数能力对模糊PID控制过程进行学习和插补。研究结果表明:与PID控制器相比,CMAC-模糊PID控制器能够有效地解决液驱并联机构多维力加载系统复杂的跟踪问题。
基金National Natural Science Foundation of China （50825502）
文摘This article, in order to precisely impose friction on aircraft and weapon actuation systems, presents a new friction loading method characteristic of ＂torque-zero velocity＂ switching control with an electro-hydraulic load simulator. As the general Stribeck friction model has little related to static friction, it proposes a ＂torque-zero velocity＂ switcher, in which a zero-velocity controller is developed to load the static friction and a torque controller the kinetic friction. With the help of mathematical modeling, this article designs a ＂torque-zero velocity＂ switching controller and, correspondingly, provides a ＂dual-threshold judgment＂ algorithm. Simulation results indicate that the proposed method can be successfully used to carry out the static and kinetic friction simulation with an electro-hydraulic load simulator.
文摘分析了电液伺服加载和板簧加载的工作原理与特点,搭建了试验平台,并分别对两种加载方式进行了试验研究.理论分析和试验结果均表明:以板簧加载为代表的机械加载,结构简单、成本较低,但加载精度低,灵活性差,仅能实现近似线性的简单加载规律;电液伺服加载结构复杂,但能够实现多种加载规律,可模拟导弹舵机的真实负载状态.采用基于小脑模型神经网络(cerebellar model articulation controller,CMAC)的复合控制方法能够有效抑制多余力,提高加载精度.
