ABSTRACT
Firstly we need to simplify the driving system reasonably to build a theoretical model of hydraulic cylinders’ movement. The present researches related to the driving system of shield are mostly based on four-region system which simplifies the driving system by dividing the cylinders into four sections, namely top region, bottom region, left region and right region [6], as showed in Figure 1. During the excavation of shield, it will drive straightly when all the cylinders in four regions work together; it will
1 INTRODUCTION
Nowadays, the existing control strategies of shield rectification are mostly based on the operators’ judgments after the analysis of the measured date [1]. With the continuous development of computer technology, more and more researchers start to focus on the work of auto-rectification of shield machine. In the procedure of this, analyzing the earth pressure around the shield and establishing an accurate theoretical model of shield during excavation is an important process [2, 3]. We think that analyzing the relationship between the stroke length of cylinder and the attitude angle of shield through studying the theoretical model is helpful to establish the model. Unfortunately, it is extraordinary difficult to establish an accurate mathematical model in traditional ways because of the heavy load, dynamic load and offset load characteristics presented by the shield machine during excavation [1, 2, 3]. In order to solve this problem, finite elements methods are involved by many researchers to simulate the driving process of shield, which is helpful in establishing the theoretical model [1, 4, 5].
