Dimensional Synthesis Of Spherical Four Bar Crank Slider Mechanism

The dimensional synthesis of spatial linkage mechanism (which contains function synthesis, path synthesis and rigid-body guidance synthesis) is an important part of linkage design. The design of linkage mechanism comparing with planar linkage, there are less study on the spatial linkage mechanism. So, the method about the dimensional synthesis of spherical four bar crank slider mechanism is studied deeply and systematically in this dissertation, and the expert system is established as wellFunction synthesis of spherical four bar crank slider mechanismFirstly, the mathematical model of spherical four bar crank slider mechanism is established and the output function is derived as well. Based on the Fourier series theory, the relationship between output function and the basic dimensional type can be found. Then by putting the harmonic characteristic components and associated basic dimensional type of spherical four bar crank slider mechanism together, a variable step size numerical atlas database of the spherical four bar crank slider mechanism is created; Secondly, by using the fuzzy identification method, the best suitable basic dimensional type of spherical four bar crank slider mechanism for prescribed output function is obtained. Thus, the function synthesis of spherical four bar crank slider mechanism is realized by using this method.Path synthesis of spherical four bar crank slider mechanismFirstly, the mathematical model of spherical four bar crank slider mechanism is established and the coupler curve is determined as well. Then based on the Fourier series theory and the geometric properties of one dimensional and two dimensional Fourier series theory, the three dimensional Fourier series can be established. Thus, the geometric meaning of spherical four bar crank slider mechanism can be expressed in the Fourier series form, the problem about the mathematic representation of the coupler curve is solved; Secondly, based on the Fourier series theory, the harmonic component of the coupler curve can be obtained. Then, the relationship between the harmonic component of the coupler curve and the harmonic component of the dimensional type can be discovered. In order to eliminate the effects of scale, rotation and state angle input, the process of normalization is applied. By putting the basic dimensional type of spherical four bar crank slider mechanism and the corresponding harmonic component together, a variable step size numerical atlas database is established. Based on the Fourier expression of the coupler curve, the position of coupler point, real size and installing dimensions of spherical four bar crank slider mechanism can be calculated. Thus, the path synthesis of spherical four bar crank slider mechanism is realized by using this method. Rigid-body guidance synthesis of spherical four bar crank slider mechanismBased on the mathematical model of spherical four bar crank slider mechanism, the position output and the rotation angle output of spherical four bar crank slider mechanism are derived. Based on the Fourier series theory, the harmonic component of position output and rotation angle output can be obtained. Then a variable step size numerical atlas database is established. Finally, based on the theoretical formulas and the numerical atlas database, the Rigid-body guidance synthesis of spherical four bar crank slider mechanism can be realized.Generally speaking, based on the Fourier series theory and the storage of computer, this paper proposes a method for the dimensional synthesis of spherical four bar crank slider mechanism.