Modern software package application for kinematic analysis of planar linkages in the course «Mechanism and machine theory»

Russian higher education system needs to be modernized concerning educational programs in view of transition to the Bachelor’s and Master’s degree system; it is because of differences in academic term of baccalaureate. Nowadays Russian baccalaureate engineering programs are based on typical programs of five-year term being developed in the USSR. Students must acquire all the necessary information within four years instead of five years. At the same time, they should obtain sufficient professional scope and skills for solving industrial problems, as well as skills for generating new ideas. Thereupon, university teachers should pay attention to the methods that can be used for educational courses improvement. “Mechanism and machine theory” is a significant course in mechanical engineering. Kinematics of planar linkages is one of the sections of this subject. The traditional approaches in solving of kinematic problems are based on graphical methods such as a method of kinematic diagrams or a method of velocities and accelerations of vector polygons. However, for solving applied problems these methods are not appropriate at present. Simulation via special software packages is more worthwhile than graphic methods for simulation of mechanisms kinematics. The paper shows the result of special software “Universal Mechanism” (“UM”) application for making kinematic analysis of the mechanism. The kinematic analysis was carried out for four mechanisms: the slider-crank mechanism, the inversion of slider-crank mechanism, the crank-and-rocker mechanism and the six-link mechanism composed of a crank, two couplers, the rocker and a slider. With the help of the software “UM” it was carried out as follows: simulation of links and kinematic pairs of mechanisms, generation of mechanisms animation, and kinematic analysis. The kinematic parameters (velocities, accelerations of particles and links, trajectories of particles) were generated by the software automatically. The result is shown in two ways in the article. The first type is the graphics of kinematic parameters vs. time, for example a plot of absolute velocity of a particle in the middle of a coupler vs. time or a plot of angular acceleration of a rocker vs. time, or a plot of a particle trajectory. Several examples of different plots are presented in the article. The second type is a representation of velocity and acceleration vectors. The vectors are marked on the links of the mechanisms. When animating mechanisms in the “UM”, the modulus of vectors and their directions are changed. The plots and the vectors made by the “UM” are the analogues of graphical methods of kinematics. The kinematic analysis presented in the article was performed for two variants. The first variant is kinematics of the mechanism with a constant angular velocity of the cranks. The second variant is kinematics of the six-link mechanism with an inconstant angular velocity of the crank. The result presented in the article proves the necessity of wide application of “UM” and other types of special software of mechanical simulation in educational engineering. The authors give some recommendations on introduction of the “UM” and other complexes in the educational process.

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