Lei Zhaoming

Design for wireless networked control systems with time-delay and data packet dropout

The paper presents a model of a class of wireless network systems with delay and data dropout. The optimal state estimator is designed for the system by using time-varying Kalman filter on the basis of the presented model. Then, a design approach to feedback control of optimal state is presented. And the separation principle of state feedback controller and state observer is guaranteed by carrying the additional information in data packet. Finally, the stability of closed-loop NCSs is proven by applying MJLS theory.

The research of manufacturing execution system modeling based on colored Petri nets

Manufacturing execution system (MES) is defined as a system towards the level of workshop management between the schemed management system on the upper level and industrial control on the bottom level. MES is aimed at the workshops. Moreover, the workshops, acting as the manufacturing center of the enterprises, are not only the executor of production tasks, but also the feed backer of production information. Furthermore, they are distributing center of living manufacturing information. Consequently, the management of workshops, logistics management, and information integration on the level of workshops are key points in the industrially information integration. But MES is the complex DEDS (Discrete event dynamic system), there are many random factors and unstructured problems in it. Therefore it cannot be depicted by accurate formalization methods. Petri nets is the graphic modeling tool, and it can accurately depict the relation in events such as Sequence, Concurrent, Synchronization, etc. So it is the powerful tool for modeling and analyzing DEDS. Colored Petri nets is a kind of high level net system which is adopted for modeling DEDS by this paper. It can greatly reduce the complexity of system model and analyzing the performance of model, and solve the problem of model such as Deadlock, conflict, etc.

Virtual Obstacle Based Approach to Path Planning of Mobile Robot with Nonholonomic Constraints

The nonholonomic constraint in path planning is described by setting virtual obstacles. Virtual obstacles are supposed to limit the motion direction and posture in the directions that the robots or vehicles cannot move under nonholonomic constraints. The results of path planning based on virtual obstacle are kinematics traceable. And the parking posture and parallel parking in path planning of mobile robot are solved.

Research of system stability with network existing in feedback and foreward channel

This paper mainly studies the stability in the state prediction based networked control system. Considering linear control system connected with network not only between the sensor and controller, also between the controller and actuator, the controller is designed to reduce the network bandwidth in condition of keeping the system in stability. System modeling, stability analysis, controller design and simulation of the state prediction based networked control system are studied. And simulation results show the validity of the proposed controller design method.

Design of state predication controller in discrete networked control system

Networked control system (NCS) is distributed feedback control system which has the advantage of greater flexibility with respect to traditional control systems. Also, it allows for reduced wiring, as well as a lower installation cost. It also permits greater agility in diagnosis and maintenance procedures. Therefor, some problem such as time delay, data package loss, may occur in the network. Transmission, which can make the analysis to NCS a difficult task. Because the classical control theory can not be directly applied to NCS controller design. Whereafter, a delay compensation arithmetic is studied to reduce or eliminate the influence of the network transmission to the control computing. Also, the necessary and sufficient conditions for this kind of NCS stability are derivated. It is proved that networked delay can be compensated by state prediction arithmetic by the use of simulation.

Study and implementation of Precision Time Protocol with C

It is an important field of research to achieve precise time synchronization with precision time protocol in network. This paper mainly studies the kernel mechanism of synchronizing the clock between the host and slave devices with PTP, on which base the system is designed and realized through software simulation with the programming tool C#. The precision of synchronization reaches one millisecond. And simulation results show the validity of the proposed controller design method.

Media access control manner with QoS for control network

Control network takes responsibility for data communication in the networked control system (NCS), so the media access control of network is the key to guaranteeing the efficiency of the system. The paper presents a novel variable priority token passing data communication manner for the media access control in control network. The theoretical analysis, mathematical analysis and experiments are given on after the other. Comparison from experiments shows high efficiency and advantage of the presented manner than that of CSMA/CD and standard token-passing.

On Closed-loop Property of State-space Model Based Multi-horizon Predictive Control System

The closed-loop property of the state-space model base multi-horizon predictive control system with feedback correction is studied. It adopts finite horizon performance index, feedback correction and adopts multi-prediction horizon to deal with outputs with different settling time. The analysis to the closed-loop system shows that it is equivalent to a certain kind of pole-placement algorithm. Also, the condition for zero steady error is given.

Stability Analysis and State Predictor Design of the NCS with Data Packet Dropout

In view of the NCS with data packet dropout, according to which information controller update, this paper compare two different solution, and give each a stability condition in the form of LMI. proposes a method to design controller which based on state prediction. With data-packet dropouts rate constant, set up a dynamical system model for NCS and analyze the exponentially stability of NCS. Also simulation examples are given to illustrate the validity of the results.

A Design Method of Sliding Mode Controller Based on Disturbance Observer

In this paper, a design method of sliding controller with the disturbance observer is proposed for the existence of disturbance and parameter perturbation in electromechanical servo system, switch function, gain and control function are given, At the same time, stability analysis is made by means of the Lyapunov function. The sliding controller designed by the method has a lower switch gain , so chattering of sliding mode is reduced greatly. Moreover, the disturbance is compensated quickly. Simulations verified that the proposed control method has the better dynamic performance and the robust capability, and also that it has a decided advantage over the conventional sliding control in the suppression of chattering.