No abstract

Direct force control (DFC) with the advantages of simple structure, fast force response, superior control performance, is developed from direct torque control (DTC). So, it is attracting more attention, increasingly becoming a research hot in the control field. It is a valuable research to improve the operation stability of PMLSM by the direct force control. In this paper, based on DFC principle analysis, the force control and flux control theory of DFC is studied according to the mathematical model of PMLSM. The structure and implementation method of DFC is analyzed, and then the DFC system simulation model for PMLSM is built by Matlab/Simulink. The simulation results show the feasibility of the simulation model, with good static and dynamic performance.

Permanent magnet linear synchronous motors (PMLSMs) is the best driving motor for rope-less hoist system because of the advantages of simple structure, small volume, high force, unlimited hoisting height and speed. In this paper, the finite element method (FEM) is adopted to design a PMLSM with 16-pole 15-slot as a unit for rope-less hoist system. Through the FEM analysis, the EMF constant Ke and the force constant Kf of unit motor were got. Then a direct driving elevator prototype drove by the proposed PMLSM was built. Experimental results show the stable operation performance of the experimental device, having good prospects for the development and application.

The five-octave mill stochastic dynamics model was established, and then constructed the virtual rolling force excitation, converted random excitation into the rolling force deterministic harmonic excitation by taking advantage of pseudo-excitation method, finally the variance and power spectral density dynamic random changes in the roll gap was Obtained . The results show that the emergence degree of rolled-strip oscillation marks is proportional to random rolling force power spectral density, and in over the five-octave frequency, the roll gap’s dynamic variance no longer change.

The stochastic excitation power spectral density (PSD) model and ARMA time series model are established based on the stochastic rolling force acquisition data, which is processed into stationary, normal and zero mean from a aluminum hot strip tandem mill. Characteristics of rolling force ARMA time series models are discussed by means of random process theory. The rolling forces PSD function of facilitating engineering application is obtained by utilizing Levenberg-Marquardt combined with generalized global planning algorithm, and the stochastic excitation model is established. It provides the basis for the prediction of rolling force.