MODELLING OF A ROPE-DRIVEN LEVEL-ADJUSTMENT SYSTEM

摘要

This paper concerns the fields of modelling of complex systems like the level-adjustment system for precious eccentric payloads. An approximate modelling scheme for complex systems is proposed. And the scheme is composed of deducing the system's mathematical model, selecting some typical operating points, calculating the solutions on the sampling points, and establishing a function fitting model. Under the guidance of the approximate modelling scheme, the model of a complex level-adjustment system, composed of a four-rope-driven level-adjustment robot and an eccentric payload, is established. As the system is very complicated, it is decomposed into two simplified 2D subsystems whose mathematical models are deduced with some necessary and feasible assumptions. Although the analytical solution of the mathematical model is hard to obtain, its numerical solution can be calculated with the help of Genetic Algorithm. Hence, some typical sampling points of the subsystem are selected, and an approximate function fitting model of the 2D subsystem is established based on fuzzy systems according to the numerical solutions on the sampling points. Fortunately, the error analysis of the approximate fitting model shows that the precision of the fitting model is satisfied.