Liu Guo-ping

The Computer Simulation and Real-Time Stabilization Control for the Inverted Pendulum System Based on LQR

The paper established mathematical model of inverted pendulum system, based on the elaborate mechanical analysis. According linear quadratic optimal control theory, the paper put forward an Linear Quadratic Regulator(LQR) for the system. The simulation result shows that the inverted pendulum system with the state feedback matrix can realize the pendulum angle and the carriage position stabilization control. In addition, the real-time control of the pendulum has been accomplished successfully based on the real-time control model built in Simulink. The result of real-time control experiment is simular to the simulation, which also validated the correctness of the theoretical analysis and the rightness of the computer simulation. In addition, comparison analysis between the simulation and real-time control experiment is carried out.

Color image encryption algorithm with realitypreserving fractional discrete cosine transform and spatiotemporal chaotic mapping

A color image encryption scheme is proposed based on a reality-preserving fractional discrete cosine transform (RPFrDCT) and spatiotemporal chaotic mapping. The scrambling and diffusion operations are carried out after the RPFrDCT and make three components of image affect each other. The main advantages of this scheme are the real-valued output, the nonlinear manipulation, the high sensitiveness and high robustness to the cipher keys. Experimental results demonstrate that the proposed encryption scheme is feasible and effective.

Controller Design for Constant Air Pressure

Air supply is very important in coal mine, but it is difficult to maintain proper air pressure for reason of non-linear and large time-delay of air supplying system. A hybrid controller combined Fuzzy-PID and Smith predictive model is proposed after careful analysis, the controller can compensate large delay time and change the big delay time into small one, can adjust PID parameters online by Fuzzy logic. simulation indicates that its tracking precision and converging speed are high, ability of fitting model mismatch is strong, practical results demonstrate that it works better than segment PID, Variation of air pressure is limited into a range of ±2KPa.