Dynamic Modeling And Parameters Estimation Of Slider-Crank Mechanism

Taking a slider-crank mechanism as an example that is used widely in packaging mechanical systems, the model of kinematics and dynamics are established, and computer simulation and parameter estimation of the slider-crank mechanism are researched. The purpose of the thesis is to further study the kinetic disciplinarian and dynamic characteristic of the mechanism, which establishes a solid foundation for dynamic design of slider-crank mechanism.Matrix method is an advanced method of modeling the dynamic of planar multi-rigid-body systems, which has been widely used nowadays. Matrix method belongs to the absolute coordinate method. In describing position of rigid bodies, Cartesian coordinates of mass centers with respect to the system is used; in describing orientations of rigid bodies, rotation angles of rigid bodies with respect to the system is adopted. The angles are real coordinates of rigid bodies in rotating, viz., the first derivatives of the rotation angles are angle velocities and the second derivatives the angle accelerations. On the basis of analyzing the Lagrange equation and Hamilton principle, the thesis establishes the dynamic equation of the slider-crank mechanism, followed by the improvement of which in representing the dynamic equation of the system directly using displacements, velocities and acceleration of the slider. Then, numerical simulation and dynamic simulation on the slider-crank mechanism are performed, respectively, by two software: MATLAB and ADAMS. The both simulation results indicate that the dynamic equations are reliable to describe kinetic disciplinarian and dynamic characteristics of the slider-crank mechanism. At last, the kinetic disciplinarian and dynamic characteristics of the slider-crank mechanism are studied by experiments, and the results confirmed correction of suggested dynamic equation.For the uncertain parameters in the slider-crank mechanism, the thesis takes the representative friction coefficient between the slider and its sliding plane and mass of the crank as estimated examples. Least-squares method is one of the widely used methods for solving parameters estimation problems, which could reduce the influence of the noise measurement and also has better robust in resisting the noise and disturbance. The discrete recursive estimation method of the least-squares is adopted, which obtains the real values of the friction coefficient and the mass of the crank by less times of iteration. Numerical results show the proposed method is effective for manipulating the problems with uncertain parameters and can be popularized and applied in other mechanism.