Ji Zhicheng

Model Reference Fuzzy Adaptive Control of Permanent Magnet Synchronous Motor

Permanent magnet synchronous motors (PMSM) are widely used in industrial drives due to their simple structure, high efficiency and high factor. Variable speed system of PMSM based on vector has owed an important position where has seriously requirement for celerity and precision. Firstly, the controlling characteristics and working principles of PMSM are analyzed, and the PMSM precision mathematical models are established based on the dq reference coordinates by strict analysis and calculation. The fuzzy model reference adaptive control method uses the fuzzy basis function expansion to represent the unknown parameters and change the identification problem from identifying the original unknown parameters to identifying the coefficients of fuzzy basis function expansion. The stability and convergence properties of the controller are ensured. The results of the simulation based on Matlab and dSPACE experiment show the fuzzy adaptive speed controller has high control and parameter track performance.

Finite-Time Stability Analysis for a Class of Continuous Switched Descriptor Systems

Finite-time stability has more practical application values than the classical Lyapunov asymptotic stability over a fixed finite-time interval. The problems of finite-time stability and finite-time boundedness for a class of continuous switched descriptor systems are considered in this paper. Based on the average dwell time approach and the multiple Lyapunov functions technique, the concepts of finite-time stability and boundedness are extended to continuous switched descriptor systems. In addition, sufficient conditions for the existence of state feedback controllers in terms of linear matrix inequalities (LMIs) are obtained with arbitrary switching rules, which guarantee that the switched descriptor system is finite-time stable and finite-time bounded, respectively. Finally, two numerical examples are presented to illustrate the reasonableness and effectiveness of the proposed results.

Fuzzy adaptive control for Wind Energy Conversion System based on model reference

Considering wind power generation system with variable-speed squirrel-cage induction generators (SGIG), a Model Reference Fuzzy Adaptive (MRFA) controller was proposed for harvesting the maximum power from wind, The designed MRFA controller was established by embedding fuzzy controller into model reference adaptive control framework, substituting complicated traditional adaptive rules with the fuzzy inverse model. The simplified control model was applied to the Wind Energy Conversion System (WECS) and the simulation was well done. The simulation results show that the proposed controller has the advantages of shortening the time for system adjustment and quickening the response speed, higher anti -interference ability and adaptability to parameter varation than conventional PID controllers.

Steganalysis for Quantization Index Module Hiding Scheme Based on Guassian Distribution

Quantization index module is a normal type of information hiding scheme, but the Steganalysis methods are not accuracy enough to detect them. A novel steganalysis method is proposed on the basis of center limitation theorem. One concise statistics is constructed to detect this kind of steganagraphy algorithms. A DCT-based image steganographic method which is recently advanced as resisting statistical attack is studied and the experimental results indicate that this technology is applicable for the detection of the quantization index module embedding algorithm.

Simulation Study on Tracking Control of Mobile Robot Based on Cascaded Adaptive Approach

Considering a general kinematical case of mobile robot, with an offset from intersection of rear wheel axis and symmetry axis, new error dynamics are derived. Using cascaded system approach, a tracking controller is constructed. The re-exponential convergence of tracking error dynamics, in combination of closed-loop controller, is guaranteed by means of cascaded system theory. Additionally, extending the result into dynamics model by adaptive approach. Simulation study validate the effectiveness and feasibility of the proposed controller both in kinematics and dynamics models.

The Integrated Design of Control and Scheduling for Networked Control System

Based on existent results on control network performance and scheduling in protocol layer, the paper analyzes the scheduling algorithm of networked control systems in application layer, and structure multi-task networked control systems for scheduling simulation in virtual platform. In addition, this paper explores technologies for integration of control and scheduling design. The influence of sampling period to NCS is discussed. Based on control and network scheduling, an optimized model and sampling period selection algorithm are proposed. An example shows that the algorithm satisfies performance requirement for NCS, optimizes network scheduling, and improves network efficiency.

Dynamic Scheduling and Robust Control Co-Design for Networked Control Systems

A dynamic scheduling strategy based on network running situation is proposed to allocate network bandwidth by adjusting the sample periods of control systems sharing CAN resource in the networked control systems. Then the NCS is a vary-sample period system which is modeled as a class of discrete switched systems when network-induced delay and data-packet dropout exist. Based on the model, the approach of robust controller design is studied. Finally, a group of simulations validate the effectiveness of the control and scheduling co-design method.

On Fuzzy Controller of Three-level DC/DC Inverter

Taking BUCK Three-level DC/DC inverter for example, the fuzzy controller of Three-level DC/DC inverter is designed. The proposed controller is implemented with two control loops. The outer loop is voltage loop with fuzzy controller and pure integral, generates the command inductor current. The inner loop is current loop with PI controller. The simulation results verify the effectiveness of the algorithm.

Simulation Modeling Research of Permanent Magnet Synchronous Motor Control System

Based on the mathematical model of permanent magnet synchronous motor (PMSM), a novel method of modeling PMSM control system has been proposed. The control system adopts the double loops method. In the system, a PI controller is adopted in the speed loop and a PWM current controller is adopted in the current loop. After that, the simulink results of the power losses in IGBTs in different carry frequencies are compared. The simulink results show the validity of the modeling method. This novel method offers a new thought way for designing and debugging actual motors.