Study On Some Key Technologies Of A Five-Axis Hybrid Machine Tool

The research on PMT(Parallel Machine Tool) involves mechanical engineering, electronics, automation, computer, sensor and so on. In this paper, combining closely with the need of the development of the new numerical machining furnishes, some key technology of a new typed hybrid machine tool are systematically analyzed. A 2-DOF(Degree-Of-Freedom) parallel translational mechanism and a 2- DOF spherical five-bar mechanism are used to realize the translational and rotational degree of freedom of the PMT and a new type synthesis of a new typed five-axis hybrid machine tool is given. The kinematics of the PMT is analyzed and the analytic expression of forward and inverse solution to position for the PMT is obtained. The Jacobian matrix of velocity of the PMT is obtained by using screw theory and the asymmetry of the matrix is analyzed. Based on two critical index: the ability of realizing the location and orientation and dexterity measures, the dimensional synthesis of the translational mechanism is designed. To get the mapping relationship between the influencing factors and the end error of the PMT, the kinematics equation are differentiated. The analytic expression of the geometric error of the PMT is obtained by using the superposition theorem and comprehensively considering the influencing factor. By comprehensively considering the three evaluation indicators: comprehensive error sensitivity, absolute error sensitivity and error tropy sensitivity, the influence of the influencing factor effecting on the end effector is analyzed. The force Jacobian matrix is established by using principle of virtual work and considering the decoupling character of the PMT. The bearing capacity of the PMT is analyzed by using the singular value of the force Jacobian matrix. The briefly expression of flexibility is obtained without regard for minute influence factors and catching hold of the principal contradiction. Based on the above, the flexibility of the PMT is analyzed. The kinematics of the PMT is simulated by using OpenGL based on VC++.