Yin J.,Nanhang Jincheng College |
Yin J.,Nanjing University of Aeronautics and Astronautics |
Luo F.,Nanjing University of Aeronautics and Astronautics
Zhongguo Jixie Gongcheng/China Mechanical Engineering | Year: 2014
To solve the problem that the motion time calculated from acceleration and deceleration control before interpolation control in CNC system, on the basis of continuous time velocity profiles and the principles of displacement equivalent transformation, an algorithm for the generation of periodic discrete velocity profiles was proposed, whose motion time fited into an integral number of interpolation periods. The feedrate computational formulae for each interpolation period of different acceleration and deceleration phases were deduced in detail in cases where both start speed and end speed were any desired positive real number. The proposed method did not need variant interpolation periods and it was easy to apply in traditional servo motion control system. The interpolation instance shows it is able to generate such velocity profile that the constant speed is strictly equal to instruction speed and guarantees the velocity at the segment terminal to be the specified speed. In addition, it has high motion efficiency and interpolation accuracy. ©, 2014, China Mechanical Engineering Magazine Office. All right reserved.
Hufenqiao,Nanhang Jincheng College |
Bin J.,Nanjing University of Aeronautics and Astronautics
2011 International Conference on Electric Information and Control Engineering, ICEICE 2011 - Proceedings | Year: 2011
This paper considers the problem of actuator fault diagnosis for a class of systems with two kinds of uncertaintiesunstructured uncertainty and structured one. To detect the unknown fault signals, the observer is designed for a system augmented by a dynamical model of the fault signals. It is well-known that sliding mode observers designed for systems with matched uncertainty require an upper bound to be known exactly. To remove this requirement, a novel sliding mode observer is proposed. The novelty lies in the mechanism introduced to update the sliding mode observer gain for counteracting uncertainty. As a result, the knowledge of its upper bound is not required. It is proved that the observer can guarantee the state estimation error convergent asymptotically. Finally, a simulation study of an aircraft system is presented to show the effectiveness of the proposed scheme. © 2011 IEEE.
Zhao C.,Nanhang Jincheng College |
Chen S.,Jiangsu University |
Wang J.,Jiangsu University
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2015
The objective of this research was to supply theoretical bases for design and optimization of stiffness and damping parameters of active suspension system based on LQG control. Taking linear and nonlinear half car models with 4-degrees of freedom (DOF) as research examples respectively, influences of the above two parameters on active suspension system were analyzed through theoretical derivation and numerical simulation. Theoretical derivation about the linear model showed that the Ricatti Equation's solution of the active suspension system based on LQG had nothing to do with stiffness and damping parameters. Result came as that the time domain response of the active suspension system had nothing to do with stiffness and damping parameters. Numerical simulation about the linear model revealed that each integral force made up with stiffness force, damping one and active control one were independent of the other and invariable when stiffness and damping parameters were changed, and the global damping characteristics of the active control obviously became negative from positive with its parallel damping parameter increasing. As for the nonlinear car model in general, three steps, including linearizing the control system, designing LQG controller for the linearized control system, and de-linearizing in control implement, were executed to achieve the LQG controller for the nonlinear active suspension system. The design process showed that the integral forces were not influenced by stiffness and damping parameters, because their force actions were counteracted in the above linearizing and de-linearizing steps. Thus, the above results about the linear active suspension system were also true when the active suspension system was with nonlinear stiffness and damping characteristics. © 2015, Chinese Society of Agricultural Machinery. All right reserved.
Wang J.,Hohai University |
Wang J.,Nanhang Jincheng College |
Shen J.,Hohai University |
Zhang A.,Hohai University
International Conference on Internet Technology and Applications, ITAP 2010 - Proceedings | Year: 2010
This paper defines the concept of water pollution emergencies, and studies the life cycle of such cases. Taking blue-green algae in Taihu Lake as an example, it analyses the jia effects of water pollution emergencies on employment, as well as the indirect impact through three aspects which are industrial restructuring, technical progress and economic changes on employment. Then the paper holds the opinion that the effectiveness of water pollution impacts on employment will be well influenced by residents' response capacity, information dissemination, and other factors. ©2010 IEEE.
Li H.,Nanjing University of Aeronautics and Astronautics |
Zhou J.,Nanjing University of Aeronautics and Astronautics |
Tan J.,Nanhang Jincheng College |
Wang F.,Nanjing University of Aeronautics and Astronautics
Shuju Caiji Yu Chuli/Journal of Data Acquisition and Processing | Year: 2014
A multi-objective particle swarm optimization (MOPSO) with an initial non-inferior solution from maximizing directivities of conformal antenna array is proposed to get Pareto optimal solutions for desired multi-beam and low sidelobes. The proposed algorithm first uses multi-objective decomposition strategy to get a non-inferior solution by the weighted linear combination of multiple single-beam optimal solution. Then, the local search strategy based on the particle space and target space constraints at the same time in MOPSO is designed to achieve optimization of multi-beam and sidelobes. Results indicate that the approach can effectively get Pareto optimal solutions for multi-beam forming with low sidelobes of the satellite conformal array antenna.