Robust Control Application In Electromechanical Actuator

This dissertation mainly investigates some robust control strategies of the electromechanical actuator which is supposed to be activated by the sinusoidal permanent magnet synchronous motor (PMSM) and limited angle torque motor (LATM). Considering that electromechanical actuator (EMA) has the feature of being sensitive to the parameter perturbation and load disturbance, being poor in rigidity etc., deep research has been done to the principle and design method of the EMA control system by using the robust control theories.The main work of this dissertation includes:1. The structure and principle of two different types of EMA are systematically presented. The load characteristics and mechanical characteristics are analyzed with emphasis on the influence of the hinge torque on their dynamics and static characteristics. On the basis of these, the structures of the actuator loop with their feedback types are studied.2. Mathematical models of the EMA activated by PMSM and LATM are established. Furthermore, vector control methods to PMSM are studied with the result that the current vector decouple is actually an approximate static linear decouple control, viz. an incomplete decouple.3. The robust H∞ control are systematically studied, with the thoroughdiscussion of the method to convert the robust H∞ control problem with the parameter uncertainty to a standard H∞ control to be solved and general robust H∞ control problem under the mismatched disturbance is also proved.4. Robust control methods of EMA are studied. Pointing to the problem of conservative in the H∞ robust control, three types 2-DOF robust control strategiesof different structure are proposed to enhance the dynamic performance of the system on the premise that the robust performance of the system are ensured. Simulation results are shown to prove this.5. Standard H2/H∞ and robust H2 / H∞ mixed control problems aresystematically analyzed by the method of linear matrix inequation. Design method of the optimum guaranteed performance control rule as well as the one which satisfies the given disturbance attenuation degree and performance constraints are discussed6. Design method of the electromechanical actuator controller based on the robust mixed H2/H* control theory is studied, taking advantage of the priority of thelinear matrix inequation in solving the problems of the multiobject control, the robust mixed H2/H* control problem of the electromechanical actuator under thecondition of parameter perturbation and external disturbance can be transformed to the solving of the linear matrix inequation. Good simulation results are obtained by the appropriate choose of the state variance, definition of the external disturbance parameter, and adjustment of the coefficients parameter matrix.7. Two different methods of PMSM vector location estimation are proposed with the corresponding simulation results. The principle and method for determining the rotor initial position is introduced. Moreover, an improved method is proposed for the phase current reconfiguration on the basis of the direct current circuit.8. Driver hardware of the EMA is designed, with the schematic diagram of the corresponding components. At the same time, principle and producing method of the SVPWM used in the system are analyzed and discussed.