| Construction crane is very important in various fields of national economic construction,and telescopic boom crane which is one kind of construction crane has many desirable advantages such as stability,mobility,flexibility and high efficiency.With the progress of science and technology,crane develops towards intelligence,large size,and lightweight.The volume and weight of hoisting load is larger,and the crane work environment is becoming more and more complex.In order to reduce mistakes and accidents during the work,it is necessary to make a detailed hoisting plan before the crane hoist work.By applying virtual reality to simulate the hoisting project is the development trend.However,in crane virtual reality system there are few precise simulation research achievements by applying kinematics and dynamitic,there are no research in simulating heavy load swing and the geometric non-linearity of super long boom which are caused by crane compound movement.This dissertation takes telescopic boom crane as research object,and researches the application of kinematic,dynamic and large deformation in virtual reality.The main contents are summarized as follows:Based on the Lagrange method,the kinematic and dynamitic models of telescopic boom crane hoisting load are established.Firstly,the kinematic and dynamitic models of simple pendulum and multi-linkage crane,which is from simple to complex and from fixed length to variable length wire rope,are established.The crane working conditions contain luffing,rotation,and load lifting,and from these working conditions,single movement or compound movement is simulated by above models.The analyzed results show that the swing of heavy object is very observe,the impact of compound movement must be considered.The equations of the model are succinct and convenient to be solved.As a result,these equations of the model can simulate the swing of heavy load in virtual reality system.The kinematic and dynamic models of telescopic boom crane are established based on multi-rigid body system theory.Six subsystem models of crane are established by applying multi body system dynamic theory,such as carriage car body sub model,carriage car frame sub model,and upper carriage rotary platform sub model,telescopic boom frame sub system,hook sub model,and ground stress sub model.All these models are tested by ADAMS.Compared with multi-stage rod or multi deformable body models,wire rope simulated by applying Algebraic constraint equation has less degree of freedoms and computation and can improve computational efficiency.The dissertation researches the fast computation method of telescopic boom crane deformation based on geometrical non linear theory of space beam.Firstly,the telescopic boom crane is simplified model by using beam element finite element method.And by applying polynomial fitting method,the fitting formulas are obtained,which can describe heavy load,angle of boom frame luffing,and length of boom frame these three variables and horizontal displacement of each node of boom,vertical displacement,and deformation rotation angle.The fitting formulas realize the fast accurate computation of deformation and stress,and can reduce computation amount.The fitting formulas finally solve the problem that is massive computation speed through the finite element method cannot satisfy the real-time interactive of virtual device.Based on the research of heavy load swing model and the fast computation of large deformation of crane and by applying telescopic boom crane virtual system,the simulation is accomplished considering large deformation of kinematic and dynamic of telescopic boom crane virtual simulation system.Compared the parameter and action sequence between two kind of crane virtual simulation system,the swing of heavy load and deformation of boom frame can affect the formulation of the hoisting proposals,and the system can supply reference for more reality simulation of crane virtual reality.The research results indicate that the virtual simulation models of telescopic boom crane which consider load lifting,luffing of boom frame,revolution,telescope,swing of heavy load,and large deformation can reflect the fact more reality.The research is significant in formulating and simulating the large hoisting scheme of crane and can supply the reference for accomplishing the whole hoisting work intelligentization,high-speed,economization,and safety. |
