华北理工大学硕士学位论文
- II -
Abstract
The linkage mechanism is widely used in various types of machinery and
instruments due to its advantages such as large bearing capacity, low wear, long life, and
meeting the requirements of various laws of movement. The subject comprehensively
used mechanism theory, computer technology, software programming, etc., and carried
out the scale synthesis and design results of the planar link mechanism according to the
actual requirements such as the stroke speed ratio coefficient K, the corresponding
movement law of the two side links, and the expected trajectory.
In-depth research was made on the optimization design of the crank rocker
mechanism and the offset crank slider mechanism according to the stroke speed ratio
coefficient K. The values and mathematical relationships of the relevant parameters of
type I and II crank rocker mechanisms and offset crank slider mechanisms were deduced,
and a mathematical model for solving the minimum transmission angle
was
constructed. A 3d surface diagram was drawn. It can quickly complete the design of the
crank rocker mechanism / offset crank slider mechanism that realizes the rocker swing
angle / slider stroke and stroke speed ratio coefficient and the best force transmission
performance.
The design problem of the crank rocker mechanism that realizes the corresponding
movement law of two side links was studied, the theoretical derivation was established,
the mathematical model of optimal design was established, the selection and
determination of the number of design variables were discussed in depth, drawn and
analyzed the 3d surface graph and 2d contour map of the deviation of the joystick angle.
The modeling and analysis of the secondary optimization that optimizes the force
transmission performance within a small range were studied. It can quickly complete the
design of optimal reproduction of the movement law of the side link of the crank rocker
mechanism and the optimization design of the force transmission performance to control
the deviation of the movement law within a small range.
The optimized synthesis of the desired trajectory of the hinge four-bar mechanism,
the double-crank hinge five-bar mechanism, and the single-loop hinge six-bar mechanism
were studied respectively. The meaning of the harmonic characteristic parameters of the
coupler curve, the extraction algorithm and the influencing parameters were studied in
depth, and the mathematical equations for solving the dimensions of each mechanism
were derived. With the smallest difference in amplitude between the expected trajectory
and the harmonic characteristic parameter of the point P trajectory on the coupler as the
optimization target, the mechanism synthesis with the best transmission characteristics at
any point trajectory can be performed.
In addition, kinematic equations were established for all the above-mentioned
mechanisms, and the real-time dynamic simulation and kinematic analysis of the
mechanisms were achieved with Matlab.With the help of GUI technology, the entire
content was organically integrated, and a user-friendly computer-aided design system
was written. The design requirements were entered through human-computer interaction
to quickly complete the synthesis and visualization of a more convenient method and
means for the design of the planar link mechanism.
Figure43; Table9; Reference55
Keywords:
linkage mechanism，Matlab，harmonic characteristic parameter method，kinematics
analysis，mechanism synthesis
Chinese books catalog:TH112
