Research On Problems Of DC Servo Motor Control In Network Environment

Network control system, as a new type of distributed and intelligentized control system, has got the comprehensive attention and support of scholars. Network control system has many advantages such as simple structure, high reliability, good flexibility and resource sharing. DC servo motor is widely used in industrial production, vehicle, household appliances and other areas. DC servo motor has many characteristics such as strong sensitivity, effective implementation and short response time. At present, the researches of network control system and the traditional control ways of DC servo motor have already acquired abundant achievement, but the research on the combination of the two is not enough. So it has important practical application of significance to introduce the network control structure to the traditional DC motor control system and research the problems of transfer delay and data packet dropout. This paper has selected DC servo motor as the study object to set up the model of network control system and given the design method of controller, observer and filter from theory when transfer delay and packet dropout exist at the same time. The main contents are as following:(1) For the influence of fixed short time delay and packet dropout in the network control system of DC servo motor, a state feedback H_∞ controller design is studied. Assume transfer delay is a constant which is less than one sampling period and packet dropout obeys Bernoulli binary sequence with known probability. When the system adopts the zero-input strategy and the states are measurable, a state feedback H_∞ controller is designed to ensure that the closed-loop system achieves mean square exponential stability and prescribed H_∞ performance. Based on Lyapunov stability theory, the sufficient condition of the existing of the controller is given in terms of linear matrix inequalities. Finally, the parameters of the controller are obtained by solving the linear matrix inequalities.(2) For the influence of fixed short time delay and packet dropout in the network control system of DC servo motor, an observer-based H_∞ controller design is studied. Assume transfer delay is a constant which is less than one sampling period and missing measurement data satisfies Bernoulli distributed sequence with known probability. When the system adopts the hold-input strategy and the states are unmeasurable, an observer-based H_∞ controller is designed to ensure that the closed-loop system achieves mean square exponential stability and prescribed H_∞ performance. Based on Lyapunov stability theory, the sufficient condition of the existing of the observer and controller is given in terms of linear matrix inequalities. Finally, the parameters of the observer and controller are obtained by solving the linear matrix inequalities.(3) For the influence of uncertain short time delay and packet dropout in the network control system of DC servo motor, an observer-based H_∞ controller design is studied. The uncertainty of transfer delay can be modeled as the uncertainty of system parameters and packet dropout obeys Bernoulli binary sequence with known probability. When the system adopts the hold-input strategy and the states are unmeasurable, an observer-based H_∞ controller is designed to ensure that the closed-loop system achieves mean square exponential stability and prescribed H_∞ performance. Based on Lyapunov stability theory, the sufficient condition of the existing of controller is given in terms of linear matrix inequalities. Finally, by solving the linear matrix inequalities, we can obtain the parameters of the observer and controller.(4) For the influence of random one step time delay and packet dropout in the network control system of DC servo motor, the H_∞ filter design is studied. A new mathematical model is used to describe such a network control system with transfer delay and missing measurement data at the same time. According to this model, a H_∞ filter is designed to ensure that the closed-loop system achieves mean square exponential stability and prescribed H_∞ performance. Based on Lyapunov stability theory, the sufficient condition of the existing of the filter is given in terms of linear matrix inequalities. Finally, by solving the linear matrix inequalities, we can obtain the parameters of the filter.