Research On Design And Dynamic Performance For Segment Assembly Erector Of Shield Tunnel Machine

The 21st century is the development and utilization of underground space of the century. Shield construction technology has been widely used in railway tunnels, crossing the river tunnels, highway tunnels and urban underground works. Full-face tunnel boring machine is a large-scale underground construction equipment which integrated mechanical, electrical, fluid, light, computer technology, and it is the prerequisite for large-scale development and utilization of underground space.Segment assembly system is the key subsystems of shield machine.As complex structure, high efficient, high-precision for location / detection , complex properties of static and dynamic and large work load, etc, it has yet to be realized to be made all in domestically.Closely to meet the demands to develop a new segment automated assembly machine, supported by the "Eleventh Five-Year" national major scientific and technological projects—full-face boring machine project funding,for the objective to develop shield segment automatic assembly machines integrated system with own intellectual property rights, this article has system studied the key technologies of the hybrid configuration segment assembled robot,including the concept of machine design, integrated architecture, kinematic performance analysis, dynamic performance analysis and stiffness analysis,etc. Based on the above results, a heavy segment assembly prototype machinery for medium and large-diameter shield tunnel construction is developed, and conducted simulation and prototype testing. The work will gradually form a shield of their own intellectual property rights related equipment to replace foreign products, improve the shield machine in the design and manufacture of equipment and reduce the cost of construction is important and so on.In this paper, the main results of research as follows: (1)From the engineering demands, functional requirements and mechanism principles, the selection principle of segment assembling machine is set up, a new machine configuration program of the hybrid construction segment assembled machine whose position and posture are decoupling is proposed. Then the issues of posture mechanism conceptual design boil down to a selection problem for less constrained degree of freedom parallel mechanism with a class of just kinematic chains. Based on Lie groups and differential manifold theory, the basic configuration of posture mechanism is synthesized, and then complete the six-degree-of-freedom hybrid configuration segment assembly machine's conceptual design.(2)Based on Lie group theory, the kinematic model of posture mechanism is build, the inverse postion solution and the speed mapping equations are set up,and Jacobian matrix is obtained. Through the input and output speed law, singularity analysis of posture mechanism is carried, singularity criterion of 3-SPS-1-S mechanism is proposed, and its two singular configuration is gained. To avoid singularity and to enhance the stability of whole machine, a redundant drive 4-SPS-1-S mechanism is derivatived. As kinematics performance evaluation index,the Jacobian condition number and manipulability degree are established. The 3-SPS-1-S and 4-SPS-1-S two parallel mechanism performance analysis is compared, research results show that redundant drive 4-SPS-1-S mechanism has better isotropic and manageability, it is more suitable as profile bodies of segment assembled machine.(3)Based on the Newton-Euler and Lagrange equation, dynamics model of posture mechanism is the established,which lay the theoretical foundation for dynamic performance analysis and implementation of control. In accordance with segment assembled machine characteristics, the use of variable structure control method and control strategy to control its implementation is proposed. Two types of dynamic performance index,including bearing capacity and driven capability,are established to evaluate dynamic performance. The results show that the redundant drive 4-SPS-1-S mechanism has good bearing capacity and drive performance.(4)The global performance indicators,such as Jacobian matrix condition number and the maximum bearing capacity are introduced, and then dimensional synthesis can be boiled down to as follows: under the premise to meet the design task space and various constraints requirements,take the global condition number and the maximum bearing capacity as the objective function , make the multi-objective optimization design model of posture mechanism and determine the optimal scale parameter value. In the choice of optimization method, through improveing the global search, local search and pheromone update rule of ant colony algorithm, the improved ant clony algorithm for solve the continuous optimization problem is established and used in structure parameter optimization. Digital design prototype of segment assembly robot is developed basing on the determined scale parameter and it provides a detailed design program for the construction of the physical prototype.(5)Combination of shield segment assembly robot design, Utilizing virtual work principle and technique of substructure synthesis,simplified analytic model of the segment assembly robots is formulated. The model enables the rigidity distribution of the end-effector within the entire workspace to be quickly estimated in the stage of conceptual design.By means of ANSYS Parametric Design Language (APDL), finite element analysis (FEA) models of this robot are also formulated by taking into account the flexibility of machine frame. Particular attentions are placed upon:①precise FEA formulation of different type of joints, and②the development of an effective modeling strategy for the rapid rigidity estimation associated with different configurations in order to avoid FEA model re-meshing. Compare the stiffness results of analytical model and finite element analysis, the distribution of the two are basically the same,thus verify the analytical model of stiffness has a certain validity of the results expected.(6)The experimental investigation and parameters test is carried out on a segment assembly robot prototype machine. It shows that fairly good match can be achieved between the results of design theory and those obtained via experiments.This article work of creativity is summarized as follows:(1)The selection principle of segment assembly erector has been set up,the hybrid configuration segment assembly erector'configuration program which position and posture are decoupling has been constructed,and the problem of concept design for erector has been come down to the configuration selection problem for a class of less degree of freedom parallel mechanism with a appropriate restricted chain.With kinematic synthesis method based on Lie groups and differential manifold theory, the basic configuration of posture mechanism has been synthesized,and concept design of six degree freedom hybrid configuration segment assembly erector has been completed.(2)To avoid singularity and enhance carrying capacity and stability,based on 3-SPS-1-S type parallel mechanism , 4-SPS-1-S type redundancy-driven mechanism which is to be as posture mechanism has been proposed. The mechanism has such good characteristic as balance and stability, carrying capacity , and stiffness-weight ratio, and position accuracy. (3)The kinematic and dynamic models of segment assembly erector has been set up.With the introduction of kinematic performance index which includes Jacobian condition number and manipulation,and dynamic performance index which include carrying capacity and driving capacity,kinematics and dynamics performance evaluation have been carried for redundant driven posture mechanism of segment assembly erector.(4)Scale synthesis approach considering an integrated kinematics, dynamics performance has been set up.With the objective function such as Jacobian condition number and carrying capacity ,multi-objective optimization design model to determine the optimal value of scale parameter are founded. In the choice of optimization method,the improved ant colony algorithm was used and the optimizaton results more satisfactory.( 5 ) Utilizing virtual work principle and technique of substructure synthesis,simplified analytic model of the 4-SPS-1-S mechanism is formulated. By means of ANSYS Parametric Design Language (APDL), finite element analysis (FEA) models are also formulated by taking into account the flexibility of machine frame,and an effective modeling strategy for the rapid rigidity estimation associated with different configurations in order to avoid FEA model re-meshing.