Papers by Author: Gui Tao Sun

Abstract: In order to achieve the switching function of the force and position, the force control is executed when the hydraulic cylinder contacts with the mechanical objects, the position control is executed when the hydraulic cylinder is far away from the mechanical objects. This paper respectively established force control model and position control model. The position control adopts the PID algorithm and the force control adopts the fuzzy algorithm. In order to solve the jump and jitter of the parameters when force-position switching, this paper puts forward a fuzzy switching adaptive control strategy. Fuzzy switching ensures the smooth transition of the two control models, the results of simulations show that fuzzy switching not only ensures the system’s rapidity but also shows excellent robustness against variations of system parameters and external disturbances.

Abstract: In order to improve the dynamic characteristics of crossbeam of heavy NC gantry moving boring & milling machine, the ribbed slab structure of beam were analyzed and optimized with the finite element analysis software, and the comprehensive optimization method of the number, size and layout of ribbed slab were putted forward based on the classification of ribbed slab structure. According to the result of the finite element analysis, the internal type and horizontal spacing of ribbed slab are optimized to get the best number, spacing, thickness and height of ribbed slab; Under the required intensity, stiffness and stability conditions materials are distributed reasonably to reduce beam weight which make little deformation and the uniform stress distribution. The comprehensive optimization method study has reference value for ribbed slab structure design.

Abstract: Lubricant viscosity is one of the key parameters in hydrostatic bearing research. In order to solve the load capacity of hydrostatic bearing in the heavy equipment, viscosity-temperature equation of lubricant film is established, and the viscosity-temperature curve is fitted by B-Spline curve. Finite volume method is used on numerical simulation of pressure field of heavy hydrostatic bearing in constant and variable viscosity respectively and in different rotational velocity, whereafter, viscosity influence on load capacity of heavy hydrostatic bearing is discussed. The results show that, viscosity impose a minor influence on cavity pressure of hydrostatic bearing when rational velocity is low; whereas, when rational velocity is high, especially to the heavy hydrostatic bearing which with high liner velocity influence of viscosity changing must be taken into account in calculation. Numerical simulation results reflect the pressure distributing state of bearing veritably; furthermore, these provide theoretical basis for hydrostatic bearing design and lectotype in practical application.