| Advanced manufacturing and heavy industry are one of the standards that reflect the country's overall national strength,and the high-performance CNC machine tool industry plays a pivotal role in this.The CNC machine tool industry has a good application prospect in the fields of aerospace,railway,automobile,national defense and military,and has far-reaching influence.In this paper,a new five-degree-of-freedom hybrid machine tool mechanism is designed for the large-scale industrial complex slender overall structural parts with high rigidity,fast response speed and strong bearing capacity.The basis of the hybrid machine tool mechanism is designed.The theory is analyzed and its main research contents are summarized as follows:The configuration of the new five-degree-of-freedom hybrid machine tool is designed and introduced.Based on the screw theory,the mechanism of realizing the five-degree-of-freedom motion mode of the new hybrid machine tool mechanism is studied,and the correctness of the theoretical analysis is verified.Based on the screw theory,the driving input of the mechanism is selected and the singularity of the mechanism is analyzed.Kinematics analysis was performed on the new five-degree-of-freedom hybrid machine mechanism.The analytic vector method is used to solve the position inverse equation of the hybrid mechanism.The input displacement of each drive is obtained under the condition of the known dynamic platform pose and the tool nose point coordinates.The mechanism is derived by the motion influence coefficient method.The order motion influence coefficient Jacobian matrix and the second-order motion influence coefficient Hessian matrix are used to establish the kinematics model of the hybrid mechanism.The numerical search method is used to analyze the workingspace of the machine tool mechanism.Dynamics analysis of a new 5-DOF hybrid machine tool mechanism was carried out.Based on the virtual work principle of the virtual energy advantage of the machine tool mechanism as a whole,the dynamic model of the new five-degree-of-freedom hybrid machine tool mechanism is established.The simulation calculation of the machine tool mechanism is carried out by MATLAB and ADAMS software,and the results verify the correctness of the theoretical analysis of the machine tool mechanism dynamics.A processing example is given to solve the kinematics variation law of the driving rods in the process of machining.The correctness and rationality of machine tool mechanism are proved.The stiffness and static analysis of the parallel mechanism of a new 5-DOF hybrid machine tool are carried out.The static balance equation of the parallel mechanism is established by analyzing the force of the machine tool mechanism;the deformation of each branch chain under the action of constraint/couple and driving force screw is analyzed by using the principle of small deformation superposition and force screw quantity,and then the overall flexibility and stiffness matrix of the mechanism can be obtained;the relationship between the deformation of each bar and the deformation of the dynamic platform is analyzed,and the deformation of the dynamic platform is established.Static stiffness model of hybrid machine tool mechanism;By combining with an example,theoretical calculation is carried out with MATLAB,and the curve of elastic deformation of parallel mechanism(3-RPR+R)&UPS is obtained. |
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