Papers by Keyword: Nonlinear

Abstract: Because resistance of two-dimensional position sensitive detector's (PSD) photo surface is not absolute uniformity that its output is nonlinear. It is this feature enables the PSD difficult to measure small displacement. In order to solve this problem, BP neural network is proposed to solve the problem of PSD nonlinear correction after the study of traditional nonlinear correction method; BP neural network would have a strong ability of nonlinear mapping after training, and it can approach arbitrarily contact function by arbitrary precision, and MATLAB neural networking boxes can simulate BP neural network easily. Simulation and verification indicate that the method has a remarkable effect in solving nonlinear problems, and it can meet system requirements.

Abstract: A simplified mathematic model of hydro-pneumatic suspension was set up and the damping characteristic curve of hydro-pneumatic suspension was obtained accordingly. A analysis of the effect of diameter of hydraulic jar, velocity of piston, diameter of damping hole and check valve diameter on damping characteristic of hydro-pneumatic suspension was made. It showed that the major influence factors includes moving speed of piston, diameter of hydraulic jar and diameter of damping hole.

Abstract: The cable tower is the bearing component of long-span suspension bridges, and its structure is very high and bear large force, which determines the stability and is the key of safety control. As for the height of the main tower of a long-span suspension bridge up to 195.3 m, the finite element software ANSYS is used to establish a three-dimensional finite element model (FEM), and the effects of geometric nonlinearity and material nonlinearity on the stability of the main tower are analyzed. The calculation results show that geometrical nonlinearity and material defects have significant influence on the main tower stability, and the nonlinear stability should be considered under wind load in the design calculation.

Abstract: A novel strategy of online force distribution for multi-finger robot hand is developed based on impedance control. The real-time controller system including the finger dynamics and multi-fingers constraints is considered as a nonlinear system. Because when the robot hand grasps the object, the fingertip force is usually changed which could cause the grasp unstable. Our method gains the ability to deal with online grasping force distribution and can satisfy the real-time requirements at the same time. Experiment shows that our method provides the most feasible grasp configurations in real-time performance.

Abstract: This paper discusses the air spring of the lithography mechanic gravity compensation device and the working principle of pneumatic control structure, and introduces the related technical parameter design. Focus on the structure of vibration damping device design and classical control theory.

Abstract: This paper proposed a coordinate positioning method of 5-wire resistive touch screen. The 5-wire resistive touch screen applying a constant current from the four corners of the lower conductive layer, and all current flowing out from upper conductive layer. When positioning touch coordinates, first set initial preset point. Then measure the actual diagonal voltage of the touch point. Use the opposition searching method to calculate the theoretical diagonal voltage about preset and searching point. Take the theoretical minimum error diagonal voltage point as the new preset point and then searching repeatedly so that the touch point can be approached finally. The method solves the problem about nonlinear equations solution and distortion correction of the 5-wire resistive touch screen without the compensation electrode. It can narrow the frame of the 5-wire resistive touch screen and broaden its applications in a small screen.

Abstract: Boiler steam temperature controlled object has characteristics of full scope nonlinear and time-variable, which bring more difficulties in modeling and designing control systems. Adopting Jordan block in broad sense and algebra equivalence transform method, the description of transfer functions paragraphed can be transformed into that of state-space with changeable parameters. The researches on steady robustness of three tipical control systems shows that: to the high order inertia nonlinear and time-variable controlled object described by the same set of transfer functions, the Luenberger function observer established according to its any algebra equivalence state-space description, there exists a solve matrixwith order satisfy the Sylvester matrix equation under some conditions. There presents sufficient conditions to full scope asymptotically stable of three types boiler steam temperature control systems and the regulators’ steady work points. The simulation tests and engineering practices prove the correctness of theoretical analysis and steady robustness of the systems.

Abstract: This paper is concerned with the development of new adaptive nonlinear Kalman estimators which incorporate nonlinear model errors and noise statistical characteristic errors. With the adoption of fictitious noise compensation technique and actual non-divergent computation method, the new filters are aimed at compensating the nonlinear dynamics as well as the system modeling errors by adaptively estimating the noise statistics and unknown parameters. The performance of the proposed adaptive estimators is demonstrated using six-state with varying model parameters as a simulation example.

Abstract: Stochastic system widely exists in natural science, engineering and social system, and the study of stochastic system has become one of important research contents for engineering researchers. Aiming at a kind of stochastic system, i.e., nonlinear and uncertain stochastic systems, we present many widespread theoretical and applied problems in this paper, and summarize and review the main conclusions and ideas of literature related to nonlinear and uncertain stochastic systems. Further, we give some new research topics and directions. We try to provide new methods for the control study of nonlinear and uncertain stochastic systems.

Abstract: In the d-q coordinate system, UPFC mathematical model reveals a nonlinear system with features of a multi-variable, strong coupling, and more interference. In view of these system characteristics, the paper presents a nonlinear overlapping decoupled strategy with better stability and dynamic performance for UPFC control. The control strategy is analyzed and tested with the MATLAB simulative experiments. Simulation results show that the proposed control strategy can quickly and accurately respond to the needs of the power system, and realize real power and reactive power decoupling control effectively. Keywords: Dynamic Modeling, Nonlinear, Decoupling Controller, UPFC, MATLAB